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<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">Front. Cell. Infect. Microbiol.</journal-id>
<journal-title>Frontiers in Cellular and Infection Microbiology</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Cell. Infect. Microbiol.</abbrev-journal-title>
<issn pub-type="epub">2235-2988</issn>
<publisher>
<publisher-name>Frontiers Media S.A.</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.3389/fcimb.2023.1211899</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Cellular and Infection Microbiology</subject>
<subj-group>
<subject>Original Research</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Skin microbiome profile in people living with HIV/AIDS in Cameroon</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname>Ogai</surname>
<given-names>Kazuhiro</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/501923"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Nana</surname>
<given-names>Benderli Christine</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/2308701"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Lloyd</surname>
<given-names>Yukie Michelle</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Arios</surname>
<given-names>John Paul</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/2341645"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Jiyarom</surname>
<given-names>Boonyanudh</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/1518130"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Awanakam</surname>
<given-names>Honore</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Esemu</surname>
<given-names>Livo Forgu</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/2430234"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Hori</surname>
<given-names>Aki</given-names>
</name>
<xref ref-type="aff" rid="aff8">
<sup>8</sup>
</xref>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Matsuoka</surname>
<given-names>Ayaka</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Nainu</surname>
<given-names>Firzan</given-names>
</name>
<xref ref-type="aff" rid="aff8">
<sup>8</sup>
</xref>
<xref ref-type="aff" rid="aff9">
<sup>9</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/893663"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Megnekou</surname>
<given-names>Rosette</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/1150580"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname>Leke</surname>
<given-names>Rose Gana Fomban</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
</contrib>
<contrib contrib-type="author" corresp="yes">
<name>
<surname>Ekali</surname>
<given-names>Gabriel Loni</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="author-notes" rid="fn001">
<sup>*</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/764165"/>
</contrib>
<contrib contrib-type="author" corresp="yes">
<name>
<surname>Okamoto</surname>
<given-names>Shigefumi</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
<xref ref-type="aff" rid="aff10">
<sup>10</sup>
</xref>
<xref ref-type="aff" rid="aff11">
<sup>11</sup>
</xref>
<xref ref-type="author-notes" rid="fn001">
<sup>*</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/574938"/>
</contrib>
<contrib contrib-type="author" corresp="yes">
<name>
<surname>Kuraishi</surname>
<given-names>Takayuki</given-names>
</name>
<xref ref-type="aff" rid="aff8">
<sup>8</sup>
</xref>
<xref ref-type="author-notes" rid="fn001">
<sup>*</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/755976"/>
</contrib>
</contrib-group>
<aff id="aff1">
<sup>1</sup>
<institution>AI Hospital/Macro Signal Dynamics Research and Development Center (ai@ku), Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University</institution>, <addr-line>Kanazawa</addr-line>, <country>Japan</country>
</aff>
<aff id="aff2">
<sup>2</sup>
<institution>Department of Bio-engineering Nursing, Graduate School of Nursing, Ishikawa Prefectural Nursing University</institution>, <addr-line>Kahoku</addr-line>, <country>Japan</country>
</aff>
<aff id="aff3">
<sup>3</sup>
<institution>Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University</institution>, <addr-line>Kanazawa</addr-line>, <country>Japan</country>
</aff>
<aff id="aff4">
<sup>4</sup>
<institution>Biotechnology Center, University of Yaound&#xe9; I</institution>, <addr-line>Yaound&#xe9;</addr-line>, <country>Cameroon</country>
</aff>
<aff id="aff5">
<sup>5</sup>
<institution>Department of Animal Biology and Physiology of the Faculty of Science, University of Yaound&#xe9; I</institution>, <addr-line>Yaound&#xe9;</addr-line>, <country>Cameroon</country>
</aff>
<aff id="aff6">
<sup>6</sup>
<institution>Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa</institution>, <addr-line>Honolulu, HI</addr-line>, <country>United States</country>
</aff>
<aff id="aff7">
<sup>7</sup>
<institution>Institute of Medical Research and Medicinal Plant Studies, University of Yaound&#xe9; I</institution>, <addr-line>Yaound&#xe9;</addr-line>, <country>Cameroon</country>
</aff>
<aff id="aff8">
<sup>8</sup>
<institution>Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University</institution>, <addr-line>Kanazawa</addr-line>, <country>Japan</country>
</aff>
<aff id="aff9">
<sup>9</sup>
<institution>Department of Pharmacy, Faculty of Pharmacy, Hasanuddin University</institution>, <addr-line>Makassar</addr-line>, <country>Indonesia</country>
</aff>
<aff id="aff10">
<sup>10</sup>
<institution>Advanced Health Care Science Research Unit, Institute for Frontier Science Initiative, Kanazawa University</institution>, <addr-line>Kanazawa</addr-line>, <country>Japan</country>
</aff>
<aff id="aff11">
<sup>11</sup>
<institution>Division of Health Sciences, Graduate School of Medicine, Osaka University</institution>, <addr-line>Suita</addr-line>, <country>Japan</country>
</aff>
<author-notes>
<fn fn-type="edited-by">
<p>Edited by: Carlo Contini, University of Ferrara, Italy</p>
</fn>
<fn fn-type="edited-by">
<p>Reviewed by: Fengping Liu, Jiangnan University, China; Indrashis Podder, College of Medicine &amp; Sagore Dutta Hospital, India</p>
</fn>
<fn fn-type="corresp" id="fn001">
<p>*Correspondence: Gabriel Loni Ekali, <email xlink:href="mailto:eloni2000@yahoo.com">eloni2000@yahoo.com</email>; Shigefumi Okamoto, <email xlink:href="mailto:sokamoto@sahs.med.osaka-u.ac.jp">sokamoto@sahs.med.osaka-u.ac.jp</email>; Takayuki Kuraishi, <email xlink:href="mailto:tkuraishi@staff.kanazawa-u.ac.jp">tkuraishi@staff.kanazawa-u.ac.jp</email>
</p>
</fn>
</author-notes>
<pub-date pub-type="epub">
<day>31</day>
<month>10</month>
<year>2023</year>
</pub-date>
<pub-date pub-type="collection">
<year>2023</year>
</pub-date>
<volume>13</volume>
<elocation-id>1211899</elocation-id>
<history>
<date date-type="received">
<day>25</day>
<month>04</month>
<year>2023</year>
</date>
<date date-type="accepted">
<day>10</day>
<month>10</month>
<year>2023</year>
</date>
</history>
<permissions>
<copyright-statement>Copyright &#xa9; 2023 Ogai, Nana, Lloyd, Arios, Jiyarom, Awanakam, Esemu, Hori, Matsuoka, Nainu, Megnekou, Leke, Ekali, Okamoto and Kuraishi</copyright-statement>
<copyright-year>2023</copyright-year>
<copyright-holder>Ogai, Nana, Lloyd, Arios, Jiyarom, Awanakam, Esemu, Hori, Matsuoka, Nainu, Megnekou, Leke, Ekali, Okamoto and Kuraishi</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/">
<p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.</p>
</license>
</permissions>
<abstract>
<p>The presence of pathogens and the state of diseases, particularly skin diseases, may alter the composition of human skin microbiome. HIV infection has been reported to impair gut microbiome that leads to severe consequences. However, with cutaneous manifestations, that can be life-threatening, due to the opportunistic pathogens, little is known whether HIV infection might influence the skin microbiome and affect the skin homeostasis. This study catalogued the profile of skin microbiome of healthy Cameroonians, at three different skin sites, and compared them to the HIV-infected individuals. Taking advantage on the use of molecular assay coupled with next-generation sequencing, this study revealed that alpha-diversity of the skin microbiome was higher and beta-diversity was altered significantly in the HIV-infected Cameroonians than in the healthy ones. The relative abundance of skin microbes such as <italic>Micrococcus</italic> and <italic>Kocuria</italic> species was higher and <italic>Cutibacterium</italic> species was significantly lower in HIV-infected people, indicating an early change in the human skin microbiome in response to the HIV infection. This phenotypical shift was not related to the number of CD4 T cell count thus the cause remains to be identified. Overall, these data may offer an important lead on the role of skin microbiome in the determination of cutaneous disease state and the discovery of safe pharmacological preparations to treat microbial-related skin disorders.</p>
</abstract>
<kwd-group>
<kwd>skin microbiome</kwd>
<kwd>AIDS</kwd>
<kwd>HIV</kwd>
<kwd>Cameroon</kwd>
<kwd>
<italic>Cutibacterium</italic>
</kwd>
</kwd-group>
<counts>
<fig-count count="4"/>
<table-count count="4"/>
<equation-count count="0"/>
<ref-count count="47"/>
<page-count count="10"/>
<word-count count="3836"/>
</counts>
<custom-meta-wrap>
<custom-meta>
<meta-name>section-in-acceptance</meta-name>
<meta-value>Microbiome in Health and Disease</meta-value>
</custom-meta>
</custom-meta-wrap>
</article-meta>
</front>
<body>
<sec id="s1" sec-type="intro">
<label>1</label>
<title>Introduction</title>
<p>Skin is one of the most important innate immunological barriers available in humans. Together with the skin microbiome, this outer layer of protective elements have been known to play a vital role in a human&#x2019;s life (<xref ref-type="bibr" rid="B40">Segre, 2006</xref>). In fact, impairment of the skin microbiome has been suggested to be closely associated with the occurrence of several dermatological conditions (<xref ref-type="bibr" rid="B18">Fredricks, 2001</xref>; <xref ref-type="bibr" rid="B15">Dethlefsen et&#xa0;al., 2007</xref>; <xref ref-type="bibr" rid="B28">Lunjani et&#xa0;al., 2019</xref>). Dysbiosis of the skin microbiome is involved in the occurrence of several dermatological disorders (<xref ref-type="bibr" rid="B36">Prescott et&#xa0;al., 2017</xref>) such as acne, atopic dermatitis, psoriasis, rosacea, and seborrheic dermatitis (<xref ref-type="bibr" rid="B8">Byrd et&#xa0;al., 2018</xref>). Recently, it has been reported that skin microbiota composition is subject to alteration in response to pharmacotherapeutic interventions e.g., the application of systemic antimicrobial drugs (<xref ref-type="bibr" rid="B2">Bayal et&#xa0;al., 2019</xref>). Thus, identifying factors that affect skin microbiota is crucial as they are important for maintaining skin homeostasis, thereby controlling human health.</p>
<p>Human immunodeficiency virus (HIV) infection can cause serious immune dysfunctions in the affected patients, which might modify the dynamic state of the human microbiome (<xref ref-type="bibr" rid="B42">Williams et&#xa0;al., 2016</xref>; <xref ref-type="bibr" rid="B13">D&#x2019;Angelo et&#xa0;al., 2017</xref>). Over the years, HIV infection can progressively develop into acquired immune deficiency syndrome (AIDS) which leads to a more severe condition or even the death of the infected patients (<xref ref-type="bibr" rid="B14">Deeks et&#xa0;al., 2015</xref>). Almost a million people succumbed from AIDS each year, especially in developing countries, such as the ones located in Africa (<xref ref-type="bibr" rid="B14">Deeks et&#xa0;al., 2015</xref>; <xref ref-type="bibr" rid="B43">World Health Organization, 2022</xref>). In Cameroon, for example, HIV infection has been listed as the leading cause of all deaths and remains a threatening public health issue (<xref ref-type="bibr" rid="B29">Mbuagbaw et&#xa0;al., 2016</xref>). Of all HIV-related signatures, opportunistic dermatological infections such as prurigo, Kaposi&#x2019;s sarcoma (KS), and other skin lesions are commonly observed in the AIDS patients (<xref ref-type="bibr" rid="B14">Deeks et&#xa0;al., 2015</xref>), implicating potential disturbances in the composition of skin microbiome. Although much focus has been given to study the skin-related disorders, research investigating the tripartite relationship between the immune-deficient status of the HIV-infected patient, the occurrence of dermatological conditions, and the composition of the skin microbiome remains underrepresented.</p>
<p>With the development of modern and advanced tools, human microbiome research has progressed exponentially (<xref ref-type="bibr" rid="B33">NIH Human Microbiome Portfolio Analysis Team, 2019</xref>). In relation to the alteration of microbiome under HIV-infected and/or AIDS-affected situations, several studies have been reported on gut (<xref ref-type="bibr" rid="B16">Dillon et&#xa0;al., 2016</xref>; <xref ref-type="bibr" rid="B30">Monaco et&#xa0;al., 2016</xref>), oral (<xref ref-type="bibr" rid="B45">Zhang et&#xa0;al., 2015</xref>; <xref ref-type="bibr" rid="B1">Ali et&#xa0;al., 2021</xref>; <xref ref-type="bibr" rid="B26">Li et&#xa0;al., 2021a</xref>), serum (<xref ref-type="bibr" rid="B1">Ali et&#xa0;al., 2021</xref>), and lung microbiome (<xref ref-type="bibr" rid="B47">Zhu et&#xa0;al., 2022</xref>). However, taking the topic of skin microbiome into account, to the best of our knowledge, no study has been reported on the skin microbiome in AIDS patients nor in HIV infected individuals without AIDS and how this may be associated to the presence of dermatological infections. In this study, we are seeking to characterize the composition of skin microbiota in HIV-infected patients, who may or may not have developed AIDS, to assess the presence of a dysbiosis due to immune suppression and how this dysbiosis is associated to the presence of skin conditions like prurigo or KS. Our findings shall provide important insights for further research to decipher the relationship between the patient&#x2019;s skin microbiota and the development of opportunistic infections of the skin.</p>
</sec>
<sec id="s2" sec-type="materials|methods">
<label>2</label>
<title>Materials and methods</title>
<sec id="s2_1">
<label>2.1</label>
<title>Ethical considerations</title>
<p>This study was approved by the National Ethics Committee of Cameroon (approval no. 2018/06/1045/CE/CNERSH/SP), the hospital where the research was conducted, and the Medical Ethics Committee of Kanazawa University, where the next generation sequencing (NGS) was performed (approval no. 894). All research was performed in accordance with the Declaration of Helsinki. All participants were informed by a written document about the research, and written informed consent was obtained from all participants.</p>
</sec>
<sec id="s2_2">
<label>2.2</label>
<title>Study design and settings</title>
<p>This was a part of a cross-sectional study conducted in an HIV-clinic of the Efoulan District Hospital in Yaound&#xe9;, Cameroon, and in a single university in Japan. The inclusion criterion was being aged 21&#x2013;65 years, because (1) the age of adulthood in Cameroon is 21 years old and thus it is deemed necessary to be 21 years old or older to understand and consent to this research, and (2) the skin microbiome of older people (older than ~65 years old) is reported to be affected by aging itself (<xref ref-type="bibr" rid="B31">Nagase et&#xa0;al., 2020</xref>) and thus several studies limit the age of participants being younger than or equal to 65 years old (<xref ref-type="bibr" rid="B10">Carrieri et&#xa0;al., 2021</xref>; <xref ref-type="bibr" rid="B27">Li et&#xa0;al., 2021b</xref>). The exclusion criteria were those who (1) had oral/topical antibiotics 1 week prior to the study, (2) were pregnant, or (3) were in a critical situation such as severe pneumonia, sepsis, pulmonary tuberculosis, toxoplasmosis, cryptococcosis, and meningoencephalitis. The participants were requested not to (1) take a bath or shower or (2) use emollients/creams on the sampling site, after midnight of the day of sampling (<xref ref-type="bibr" rid="B32">Nakatsuji et&#xa0;al., 2017</xref>), as these may alter the bacterial composition and interfere DNA extraction. Those who did not follow the instruction requested by the researchers were excluded.</p>
</sec>
<sec id="s2_3">
<label>2.3</label>
<title>Sample collection</title>
<p>Skin swabs were collected as described previously (<xref ref-type="bibr" rid="B3">Benderli et&#xa0;al., 2019</xref>; <xref ref-type="bibr" rid="B35">Ogai et&#xa0;al., 2022</xref>). In brief, Puritan HydraFlock Sterile Flocked Swab (25-3306-H; Puritan Medical Products Co., ME, USA) was presoaked in normal saline (S5815; Teknova, CA, USA) with 0.1% Tween 20 (28353-14; Nacalai Tesque, Inc., Kyoto, Japan) solution. Swabbing was then performed in a 5 &#xd7; 5 cm<sup>2</sup> on designated positions or in the entire area of KS. After swabbing, each swab head was cut and placed in a 1.5 mL microcentrifuge tube, carried in a cooler box with ice, and stored at -30&#xb0;C until DNA extraction. To minimize sample degradation, DNA extraction was done in the same day of sampling.</p>
</sec>
<sec id="s2_4">
<label>2.4</label>
<title>DNA extraction</title>
<p>DNA from the swab head was performed as described previously (<xref ref-type="bibr" rid="B34">Ogai et&#xa0;al., 2018</xref>; <xref ref-type="bibr" rid="B3">Benderli et&#xa0;al., 2019</xref>; <xref ref-type="bibr" rid="B35">Ogai et&#xa0;al., 2022</xref>). Briefly, the swab heads were processed with the Kaneka Easy DNA Extraction Kit version 2 (KN-T110005; Kaneka Corp., Tokyo, Japan), followed by the enzymatic DNA extraction process with QIAamp DNA Mini Kit (51304; Qiagen N.V., Venlo, The Netherlands). The extracted DNA samples were stored at -30&#xb0;C until NGS preparation.</p>
</sec>
<sec id="s2_5">
<label>2.5</label>
<title>NGS</title>
<p>The extracted DNA samples, along with the negative control (DNA extracted with swab head only) and positive control (DNA extracted from the ZymoBIOMICS Microbial Community Standard [D6300; Zymo Research Corp., Irvine, CA, USA]), were dedicated to the NGS analysis as described previously (<xref ref-type="bibr" rid="B35">Ogai et&#xa0;al., 2022</xref>). The same amount of the 16S rRNA gene from each sample was used to amplify the V3-V4 hypervariable region (<xref ref-type="bibr" rid="B11">Castelino et&#xa0;al., 2017</xref>; <xref ref-type="bibr" rid="B44">Zeeuwen et&#xa0;al., 2017</xref>; <xref ref-type="bibr" rid="B34">Ogai et&#xa0;al., 2018</xref>). After indexing with the Nextera XT Index Kit version 2 (FC-131-2001 to 2004; Illumina, Inc., San Diego, CA, USA), the library solution was loaded onto the MiSeq System (SY-410-1003; Illumina) with MiSeq Reagent Kit (version 3, 600 cycles; MS-102-3003; Illumina) and 15% PhiX Control (version 3; FC-110-3001; Illumina). The data from negative and positive controls are shown in <xref ref-type="supplementary-material" rid="SM1">
<bold>Supplementary Figure S1</bold>
</xref>.</p>
</sec>
<sec id="s2_6">
<label>2.6</label>
<title>Sequence analysis</title>
<p>The sequence analysis was done according to the Qiime2 instruction (<xref ref-type="bibr" rid="B6">Bolyen et&#xa0;al., 2019</xref>). Briefly, the raw fastq sequences were first quality-filtered and chimera-eliminated by DADA2 plugin (<xref ref-type="bibr" rid="B9">Callahan et&#xa0;al., 2016</xref>). Prior to analysis, the samples whose sequencing depth were &lt;5,000 were discarded. For taxonomic classification of amplicon sequence variants (ASVs), q2-feature-classifier plugin (<xref ref-type="bibr" rid="B4">Bokulich et&#xa0;al., 2018</xref>) was used to construct the na&#xef;ve Bayes classifier with the Silva database (version 138) (<xref ref-type="bibr" rid="B37">Quast et&#xa0;al., 2013</xref>). Beta diversity was calculated based on the Bray&#x2013;Curtis distance followed by principal coordinate analysis by using q2-diversity plugin. Alpha diversity indices [observed ASVs, Faith&#x2019;s phylogenetic diversity (PD), and Shannon index] were calculated by the q2-diversity plugin with the rarefaction at 5,000 depth of sequences.</p>
</sec>
<sec id="s2_7">
<label>2.7</label>
<title>Statistical analysis</title>
<p>All statistical analyses were performed using R statistical software (<xref ref-type="bibr" rid="B38">R Core Team, 2020</xref>) version 4.2.2. The data were expressed as means &#xb1; standard deviation or n (%) where appropriate. The boxplot denotes the 25th, 50th, and 75th percentile boxes with 25th percentile - 1.5 &#xd7; IQR to 75th percentile + 1.5 &#xd7; IQR whiskers. The relative abundance between the HIV-positive and HIV-negative population was compared by using the linear models for differential abundance analysis method (LinDA) (<xref ref-type="bibr" rid="B46">Zhou et&#xa0;al., 2022</xref>) with incorporating age and sex as covariates. For multiple comparisons of bacterial abundance, Benjamini-Hochberg&#x2019;s false discovery rate control was employed. The significant differences in beta diversity between the two groups was assessed by a permutational analysis of variance with 9,999 permutations by adonis2 function of car package (<xref ref-type="bibr" rid="B17">Fox and Weisberg, 2018</xref>) of R software. Alpha diversity between the two groups were compared by using Mann&#x2013;Whitney <italic>U</italic> test. For correlation analysis, Spearman&#x2019;s correlation coefficient was used. <italic>P</italic>-values &lt; 0.05 was considered statistically significant.</p>
</sec>
</sec>
<sec id="s3" sec-type="results">
<label>3</label>
<title>Results</title>
<sec id="s3_1">
<label>3.1</label>
<title>16S rRNA-Based metagenomic analysis of skin microbes between the healthy and HIV-infected Cameroonians</title>
<p>This study first analyzed the relative abundance and prevalence of skin-resident microbes collected from healthy Cameroonians and the ones infected with HIV: Healthy (n = 26) and HIV-infected (n = 43). The demographic information is described in <xref ref-type="table" rid="T1">
<bold>Table&#xa0;1</bold>
</xref>. Data of 16S rRNA gene sequencing analysis of skin swabs from healthy Cameroonians were overlapped with our previous study (<xref ref-type="bibr" rid="B35">Ogai et&#xa0;al., 2022</xref>). However, we applied ASV-based analysis to compare microbiome difference in higher resolution.</p>
<table-wrap id="T1" position="float">
<label>Table&#xa0;1</label>
<caption>
<p>Demographic data.</p>
</caption>
<table frame="hsides">
<thead>
<tr>
<th valign="top" align="left"/>
<th valign="top" align="left">HIV<sup>-</sup> (<italic>n</italic> = 26)</th>
<th valign="top" align="left">HIV<sup>+</sup> (<italic>n</italic> = 43)</th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">Sex, female, <italic>n</italic> (%)</td>
<td valign="top" align="left">20 (76.9)</td>
<td valign="top" align="left">34 (79.1)</td>
</tr>
<tr>
<td valign="top" align="left">Age, y, mean &#xb1; SD</td>
<td valign="top" align="left">31.2 &#xb1; 8.4</td>
<td valign="top" align="left">40.0 &#xb1; 9.3</td>
</tr>
<tr>
<td valign="top" align="left">BMI, mean &#xb1; SD</td>
<td valign="top" align="left">26.4 &#xb1; 4.1</td>
<td valign="top" align="left">25.4 &#xb1; 6.3</td>
</tr>
<tr>
<td valign="top" align="left">Time since HIV diagnosis, month, mean (min &#x2013; max)</td>
<td valign="top" align="left">&#x2013;</td>
<td valign="top" align="left">56.7 (12 &#x2013; 200)</td>
</tr>
<tr>
<td valign="top" align="left">CD4 count, cells/&#x3bc;L, mean &#xb1; SD</td>
<td valign="top" align="left">&#x2013;</td>
<td valign="top" align="left">456.4 &#xb1; 301.5</td>
</tr>
<tr>
<td valign="top" align="left">HIV medication (ART), <italic>n</italic> (%)</td>
<td valign="top" align="left">&#x2013;</td>
<td valign="top" align="left">41 (95.3)</td>
</tr>
<tr>
<td valign="top" align="left">Time on ART, month, mean (min &#x2013; max)</td>
<td valign="top" align="left">&#x2013;</td>
<td valign="top" align="left">24.8 (0 &#x2013; 96)</td>
</tr>
<tr>
<td valign="top" align="left">ART Regimen, <italic>n</italic> (%)<break/>&#x2003;TDF+3TC+EFV<break/>&#x2003;Others<break/>&#x2003;Unknown</td>
<td valign="top" align="left">
<break/>-<break/>-<break/>-</td>
<td valign="top" align="left">
<break/>33 (76.7)<break/>7 (16.3)<break/>3 (7.0)</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn>
<p>BMI, body mass index; CD4, cluster of differentiation 4; HIV, human immunodeficiency virus; ART, antiretroviral therapy; TDF, Tenofovir disoproxil fumarate; 3TC, Lamivudine; EFV, efavirenz.</p>
</fn>
</table-wrap-foot>
</table-wrap>
<p>
<xref ref-type="fig" rid="f1">
<bold>Figure&#xa0;1</bold>
</xref> shows a comparison of the skin microbiome compositions between healthy Cameroonians and their HIV-infected counterparts in the three skin sites: forehead, right forearm, and the mid-upper back. The composition of skin microbiome of all samples are shown in <xref ref-type="supplementary-material" rid="SM1">
<bold>Supplementary Figure S2</bold>
</xref>. The microbiome of the Cameroonian skin samples, in the presence or absence of HIV infection, can be classified into more than 20 genera that primarily belong to three phyla: Actinobacteria, Firmicutes, and Proteobacteria. At the genus level, most obtained sequences were <italic>Staphylococcus</italic>, <italic>Cutibacterium</italic>, <italic>Micrococcus</italic>, <italic>Corynebacterium</italic>, <italic>Kocuria</italic>, and, to a lesser extent, <italic>Acinetobacter</italic> and <italic>Streptococcus</italic> (<xref ref-type="fig" rid="f1">
<bold>Figure&#xa0;1</bold>
</xref>). In the samples collected from the surface of KS, the main bacterial genera were common, but their proportions were more diverse (<xref ref-type="supplementary-material" rid="SM1">
<bold>Supplementary Figure S3</bold>
</xref>).</p>
<fig id="f1" position="float">
<label>Figure&#xa0;1</label>
<caption>
<p>Relative abundance of skin microbiome (top 20). Neg, negative; pos, positive.</p>
</caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcimb-13-1211899-g001.tif"/>
</fig>
<p>The microbial differences between the HIV-positive and HIV-negative participants were further confirmed by the beta diversity analysis using the Bray&#x2013;Curtis distance. The principal component analysis of beta diversity showed that the skin samples (forehead, forearm, and back skin) obtained from HIV-infected Cameroonian constituted significantly different clusters from healthy Cameroonian participants (<xref ref-type="fig" rid="f2">
<bold>Figure&#xa0;2</bold>
</xref>). This result suggests that there is a difference of microbiome profiles between healthy and HIV-infected people.</p>
<fig id="f2" position="float">
<label>Figure&#xa0;2</label>
<caption>
<p>Principal coordinate analysis of beta diversity (Bray&#x2013;Curtis distance) for <bold>(A)</bold> forehead, <bold>(B)</bold> forearm, and <bold>(C)</bold> back skin. PC, principal coordinate; <italic>P</italic>
<sub>PERM</sub>, <italic>P</italic>-value of the permutational analysis of variance.</p>
</caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcimb-13-1211899-g002.tif"/>
</fig>
<p>ASV-based analysis showed that the genus or species of <italic>Micrococcus</italic> (ASV1, ASV9), <italic>Kocuria marina</italic> (ASV7), <italic>Pseudomonas</italic> (ASV15), <italic>Staphylococcus</italic> (ASV17) were significantly higher in all or some parts of skin sites of the HIV-infected Cameroonians in comparison to their healthy counterparts (<xref ref-type="fig" rid="f3">
<bold>Figure&#xa0;3</bold>
</xref>; <xref ref-type="table" rid="T2">
<bold>Table&#xa0;2</bold>
</xref>). In contrast, the genus or species of <italic>Cutibacterium</italic> (ASV3), <italic>Staphylococcus</italic> (ASV2, ASV4, ASV30), <italic>Corynebacterium tuberculostearicum</italic> (ASV12), <italic>Corynebacterium</italic> (ASV28), <italic>Delftia</italic> (ASV24), <italic>Stenotrophomonas</italic> (ASV44) were significantly lower in the HIV-infected Cameroonians (<xref ref-type="fig" rid="f3">
<bold>Figure&#xa0;3</bold>
</xref>; <xref ref-type="table" rid="T3">
<bold>Table&#xa0;3</bold>
</xref>).</p>
<fig id="f3" position="float">
<label>Figure&#xa0;3</label>
<caption>
<p>Volcano plots for relative abundance of amplicon sequence variances (ASVs) on <bold>(A)</bold> forehead, <bold>(B)</bold> forearm, and <bold>(C)</bold> back skin. The horizontal axes denote the logarithm of relative fold change (based on HIV-negative) to base 2, and the vertical axes denote the negative of logarithm of adjusted <italic>P</italic>-values to base 10. The ASVs that have <italic>P</italic> &lt; 0.05 were orange colored.</p>
</caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcimb-13-1211899-g003.tif"/>
</fig>
<table-wrap id="T2" position="float">
<label>Table&#xa0;2</label>
<caption>
<p>Amplicon sequence variances (ASVs) that showed significant increase in HIV<sup>+</sup> population.</p>
</caption>
<table frame="hsides">
<thead>
<tr>
<th valign="top" colspan="6" align="left">Increase in HIV<sup>+</sup> population</th>
</tr>
<tr>
<th valign="top" align="left">ASV ID</th>
<th valign="top" align="left">Genus (+species)</th>
<th valign="top" align="center">All position</th>
<th valign="top" align="center">Forehead</th>
<th valign="top" align="center">Forearm</th>
<th valign="top" align="center">Back skin</th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">ASV1</td>
<td valign="top" align="left">
<italic>Micrococcus</italic>
</td>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">ASV7</td>
<td valign="top" align="left">
<italic>Kocuria marina</italic>
</td>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center"/>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center">&#x2191;</td>
</tr>
<tr>
<td valign="top" align="left">ASV9</td>
<td valign="top" align="left">
<italic>Micrococcus</italic>
</td>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center"/>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">ASV15</td>
<td valign="top" align="left">
<italic>Pseudomonas</italic>
</td>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center">&#x2191;</td>
</tr>
<tr>
<td valign="top" align="left">ASV17</td>
<td valign="top" align="left">
<italic>Staphylococcus</italic>
</td>
<td valign="top" align="center">&#x2191;</td>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn>
<p>Only ASVs that passed (1) prevalence &gt; 50% and (2) abundance &gt; 0.25% were analyzed.</p>
</fn>
<fn>
<p>In the order of mean abundance.</p>
</fn>
<fn>
<p>Significancy was tested by a linear regression framework for differential abundance analysis (LinDA) with adjusted P-values by Benjamini-Hochberg&#x2019;s false discovery rate control.</p>
</fn>
<fn>
<p>All linear regression tests were adjusted for age and sex.</p>
</fn>
<fn>
<p>&#x201c;All position&#x201d; means the position term was incorporated into the covariance term of the linear regression test.</p>
</fn>
<fn>
<p>&#x2191;, significant increase. Raw statistics are shown in <xref ref-type="supplementary-material" rid="SM1">
<bold>Supplementary Table S1</bold>
</xref>.</p>
</fn>
</table-wrap-foot>
</table-wrap>
<table-wrap id="T3" position="float">
<label>Table&#xa0;3</label>
<caption>
<p>Amplicon sequence variances (ASVs) that showed significant decrease in HIV<sup>+</sup> population.</p>
</caption>
<table frame="hsides">
<thead>
<tr>
<th valign="top" colspan="6" align="left">Decrease in HIV<sup>+</sup> population</th>
</tr>
<tr>
<th valign="top" align="left">ASV ID</th>
<th valign="top" align="left">Genus (+species)</th>
<th valign="top" align="center">All position</th>
<th valign="top" align="center">Forehead</th>
<th valign="top" align="center">Forearm</th>
<th valign="top" align="center">Back skin</th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">ASV3</td>
<td valign="top" align="left">
<italic>Cutibacterium</italic>
</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center"/>
<td valign="top" align="center">&#x2193;</td>
</tr>
<tr>
<td valign="top" align="left">ASV4</td>
<td valign="top" align="left">
<italic>Staphylococcus</italic>
</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">ASV2</td>
<td valign="top" align="left">
<italic>Staphylococcus</italic>
</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">ASV12</td>
<td valign="top" align="left">
<italic>Corynebacterium</italic>
<break/>
<italic>tuberculostearicum</italic>
</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">ASV30</td>
<td valign="top" align="left">
<italic>Staphylococcus</italic>
</td>
<td valign="top" align="center"/>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">ASV24</td>
<td valign="top" align="left">
<italic>Delftia</italic>
</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">ASV44</td>
<td valign="top" align="left">
<italic>Stenotrophomonas</italic>
</td>
<td valign="top" align="center"/>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center"/>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">ASV28</td>
<td valign="top" align="left">
<italic>Corynebacterium</italic>
</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center">&#x2193;</td>
<td valign="top" align="center"/>
<td valign="top" align="center">&#x2193;</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn>
<p>Only ASVs that passed (1) prevalence &gt; 50% and (2) abundance &gt; 0.25% were analyzed.</p>
</fn>
<fn>
<p>In the order of mean abundance.</p>
</fn>
<fn>
<p>Significancy was tested by a linear regression framework for differential abundance analysis (LinDA) with adjusted P-values by Benjamini-Hochberg&#x2019;s false discovery rate control.</p>
</fn>
<fn>
<p>All linear regression test was adjusted for age and sex.</p>
</fn>
<fn>
<p>&#x201c;All position&#x201d; means the position term was incorporated into the covariance term of the linear regression test.</p>
</fn>
<fn>
<p>&#x2193;, significant decrease. Raw statistics are shown in <xref ref-type="supplementary-material" rid="SM1">
<bold>Supplementary Table S1</bold>
</xref>.</p>
</fn>
</table-wrap-foot>
</table-wrap>
<p>Overall, these findings indicated that HIV infection does affect the composition of skin microbiome in the Cameroonians.</p>
</sec>
<sec id="s3_2">
<label>3.2</label>
<title>Higher alpha diversity in HIV-infected Cameroonians</title>
<p>We calculated the alpha diversity metrics of the skin microbiome between healthy Cameroonians and the HIV-infected individuals in the forehead, forearm and the back skin, namely the number of observed ASVs, Faith&#x2019;s PD, and Shannon index (<xref ref-type="fig" rid="f4">
<bold>Figure&#xa0;4</bold>
</xref>). HIV-infected Cameroonians have a much diverse skin-resident flora at the forehead and the back, with a significantly higher alpha diversity metrices. However, no significant difference in the skin microbiome diversity of the forearm skin between both groups. These findings suggest that HIV-infected people have more diverse bacterial species than their healthy counterparts in some parts of their skin.</p>
<fig id="f4" position="float">
<label>Figure&#xa0;4</label>
<caption>
<p>Alpha diversity metrices. ASVs, amplicon sequence variances; PD, phylogenetic diversity. **<italic>P</italic> &lt; 0.01, ***<italic>P</italic> &lt; 0.001.</p>
</caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcimb-13-1211899-g004.tif"/>
</fig>
</sec>
<sec id="s3_3">
<label>3.3</label>
<title>Irrelevant correlation of CD4+ T cells count with bacterial species abundance</title>
<p>The close correlation of CD4 T cells count with the progressiveness of HIV status has been widely suggested (<xref ref-type="bibr" rid="B14">Deeks et&#xa0;al., 2015</xref>; <xref ref-type="bibr" rid="B21">Kestens and Mandy, 2017</xref>). To investigate whether the number of CD4 T cells is likely correlated with the discrepancies of skin microbe composition observed in this study, an experiment to determine the CD4 T cell count was carried out. As revealed in <xref ref-type="table" rid="T4">
<bold>Table&#xa0;4</bold>
</xref>, we observed that there is no correlation between the number of CD4 T cell count with the abundance of bacterial species recovered from the skin samples of HIV-infected Cameroonians.</p>
<table-wrap id="T4" position="float">
<label>Table&#xa0;4</label>
<caption>
<p>Spearman&#x2019;s correlation coefficients between the CD4<sup>+</sup> cell number and the relative abundance of each amplicon sequence variance (ASV).</p>
</caption>
<table frame="hsides">
<thead>
<tr>
<th valign="top" align="center">ASV ID</th>
<th valign="top" align="center">Forehead</th>
<th valign="top" align="center">Forearm</th>
<th valign="top" align="center">Back skin</th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">ASV3 (<italic>Cutibacterium</italic> sp.)</td>
<td valign="top" align="center">-0.32</td>
<td valign="top" align="center">&#x2014;</td>
<td valign="top" align="center">&#x2014;</td>
</tr>
<tr>
<td valign="top" align="left">ASV7 (<italic>Kocuria marina</italic>)</td>
<td valign="top" align="center">-0.13</td>
<td valign="top" align="center">&#x2014;</td>
<td valign="top" align="center">&#x2014;</td>
</tr>
<tr>
<td valign="top" align="left">ASV22 (<italic>Weissella</italic> sp.)</td>
<td valign="top" align="center">-0.03</td>
<td valign="top" align="center">&#x2014;</td>
<td valign="top" align="center">&#x2014;</td>
</tr>
<tr>
<td valign="top" align="left">ASV25 (<italic>Acinetobacter_haemolyticus</italic>)</td>
<td valign="top" align="center">0.24</td>
<td valign="top" align="center">0.38</td>
<td valign="top" align="center">&#x2014;</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn>
<p>Only significant (P &lt; 0.05) correlation coefficients are displayed: no significant correlation is denoted as &#x2014;.</p>
</fn>
</table-wrap-foot>
</table-wrap>
</sec>
</sec>
<sec id="s4" sec-type="discussion">
<label>4</label>
<title>Discussion</title>
<p>In this study, we carried out comprehensive analysis of the skin microbiome profile of healthy Cameroonians, at three different skin sites: forehead, right forearm, and the mid-upper back, and compared them to the ones infected with HIV. Taking advantage of the NGS method and ASV-based bioinformatic analysis, we assessed the dynamic variations of Cameroonians skin microbiome and ascertain whether topological elements might play distinctive roles in the skin microbiome diversity in the event of HIV infection. Our ASV-based analysis indicated that, in HIV-infected Cameroonians, the relative number of some bacteria increased and some decreased. Furthermore, our results clearly showed that the alpha-diversity of the skin microbiome was greater, and beta-diversity was distinct from healthy counterparts. These findings collectively suggest that HIV infection affects human skin microbiome.</p>
<p>To inspect the compositional difference in detail, we observed that the relative abundance of <italic>Cutibacterium</italic> species (spp.) was significantly lower in the HIV-infected Cameroonians than their healthy counterparts. In our previous study, we confirmed that <italic>Cutibacterium</italic> spp. was less observed in the skin of healthy Cameroonians than in that of healthy Japanese people (<xref ref-type="bibr" rid="B35">Ogai et&#xa0;al., 2022</xref>), probably due to the less sebum-rich ecological nature of Cameroonians skin that might support <italic>Cutibacterium</italic> spp. growth. It is important to note that the role of <italic>Cutibacterium</italic> spp. in the cutaneous homeostasis and skin health has been reported (<xref ref-type="bibr" rid="B5">Bolla et&#xa0;al., 2020</xref>; <xref ref-type="bibr" rid="B12">Claesen et&#xa0;al., 2020</xref>; <xref ref-type="bibr" rid="B39">Rozas et&#xa0;al., 2021</xref>). Hence, although the cause of <italic>Cutibacterium</italic> spp. decline remains to be identified, this finding is particularly interesting because HIV infection may further reduce the already low levels of <italic>Cutibacterium</italic> spp., which may adversely affect to the skin homeostasis and lead to undesirable phenotypes observed during the state of disease.</p>
<p>It is widely known that the skin microbiome can be modified by the skin-related diseases such as atopic dermatitis and psoriasis. For example, higher <italic>Staphylococcus aureus</italic> and <italic>Corynebacterium</italic> is reported in atopic dermatitis (<xref ref-type="bibr" rid="B24">Kobayashi et&#xa0;al., 2015</xref>), and colonization of <italic>Staphylococcus</italic>, <italic>Streptococcus</italic>, <italic>Finegoldia</italic>, and <italic>Corynebacterium</italic> is reported to be involved in psoriasis (<xref ref-type="bibr" rid="B20">Hsu et&#xa0;al., 2020</xref>). On the other hand, changes in skin microbiome of HIV<sup>+</sup> patients (<xref ref-type="fig" rid="f1">
<bold>Figure&#xa0;1</bold>
</xref>; <xref ref-type="table" rid="T2">
<bold>Tables&#xa0;2</bold>
</xref>, <xref ref-type="table" rid="T3">
<bold>3</bold>
</xref>) are different from those found in major skin diseases, highlighting the uniqueness of skin microbiome under HIV infection. However, there are emerging interest in skin &#x201c;mycobiome&#x201d; in recent years, and it is reported that <italic>Malassezia</italic> and <italic>Candida</italic> fungi are involved in psoriasis (<xref ref-type="bibr" rid="B19">Gupta et&#xa0;al., 2022</xref>). Analysing fungal composition, or mycobiome, of HIV patients&#x2019; skin might also give new insights about HIV-related changes in skin microorganisms.</p>
<p>The composition of skin microbiome can be affected by several intrinsic factors, such as aging, sex, and racial differences (<xref ref-type="bibr" rid="B41">Wilantho et&#xa0;al., 2017</xref>; <xref ref-type="bibr" rid="B22">Khmaladze et&#xa0;al., 2020</xref>; <xref ref-type="bibr" rid="B7">Boxberger et&#xa0;al., 2021</xref>; <xref ref-type="bibr" rid="B23">Kim et&#xa0;al., 2021</xref>). Additionally, extrinsic factors such as hygiene, lifestyle, climate and/or geographical differences are also stated to be accountable for variations in the skin microbiome profile (<xref ref-type="bibr" rid="B25">Lehtimaki et&#xa0;al., 2017</xref>; <xref ref-type="bibr" rid="B22">Khmaladze et&#xa0;al., 2020</xref>; <xref ref-type="bibr" rid="B7">Boxberger et&#xa0;al., 2021</xref>). We previously showed that Cameroonian people have significantly higher alpha diversity in skin microbiome than Japanese people do, which has been attributed to both intrinsic and extrinsic factors (<xref ref-type="bibr" rid="B35">Ogai et&#xa0;al., 2022</xref>). In this study, we observed that the alpha diversity was significantly higher in the HIV-positive individuals. Given that the participants in this study resided in the close region (Yaound&#xe9; city) of the country, and sex and age are not so different (young- to middle- aged), it is speculated that HIV infection itself, other than environmental and innate factors, influences the diversity of the skin microbiota. Further studies would be desired whether increased alpha-diversity indicates the likelihood of opportunistic skin infection. Moreover, the cause for such differences shall be an interesting venue for future research. Is it the result of HIV infection? How might HIV infection alter the number of bacterial species? Since we found that there is no correlation between the number of CD4 T cell count with the abundance of bacterial species recovered from the skin samples of HIV-infected Cameroonians (<xref ref-type="table" rid="T4">
<bold>Table&#xa0;4</bold>
</xref>), we consider that difference in the cellular adaptive immune status, at least the CD4 T cells, might not the primary cause for the different skin microbiome.</p>
<p>Another important question is whether the observed skin microbiome distinction alters the landscape of skin homeostasis in HIV-infected people, such as the integrity of skin structure and skin opportunistic infections. Such information might provide insights on how skin microbiome modulates its physiology and how those interactions may influence the patients state during the course of HIV infection. This, in the end, may provide important leads in the discovery of effective pharmacological preparations to manage microbial-related disorders in the skin.</p>
<p>Through this study, we could obtain the changes of skin microbiome in HIV patients. Although we need further studies to look into the relationship between the microbial changes and skin condition and immunological status, information of skin microbiome could be used for predicting and preventing the opportunistic infection of the skin in HIV patients.</p>
</sec>
<sec id="s5" sec-type="conclusions">
<label>5</label>
<title>Conclusion</title>
<p>In this study, we have shown the distinct skin microbiome between HIV-positive and HIV-negative Cameroonian people. This study may provide a brief but fundamental information to better understand skin symptoms and crosstalk between skin and body via the skin microbiome under the influence of HIV infection.</p>
</sec>
<sec id="s6" sec-type="data-availability">
<title>Data availability statement</title>
<p>The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found below: <ext-link ext-link-type="uri" xlink:href="https://www.ddbj.nig.ac.jp/">https://www.ddbj.nig.ac.jp/</ext-link>, DRA011596 and DRA016187.</p>
</sec>
<sec id="s7" sec-type="ethics-statement">
<title>Ethics statement</title>
<p>The studies involving humans were approved by National Ethics Committee of Cameroon (approval no. 2018/06/1045/CE/CNERSH/SP) Medical Ethics Committee of Kanazawa University (approval no. 894). The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.</p>
</sec>
<sec id="s8" sec-type="author-contributions">
<title>Author contributions</title>
<p>Conceptualization: GE, SO, and TK. Methodology: KO, YL, AH, AM, SO, and TK. Software: KO. Validation: KO, BN, AM, FN, and TK. Formal analysis: KO, BN, and AM. Investigation: KO, BN, YL, JA, BJ, HA, LE, AH, AM, GL, and TK. Resources: BN, HA, LE, RM, RL, and GL. Data curation: KO, AM, FN, and TK. Writing&#x2014;original draft preparation: KO, FN, and TK. Writing&#x2014;review and editing: KO, FN, and TK. Visualization: KO and AM. Supervision: RM, RL, GL, SO, and TK. Project administration: GL, SO, and TK. Funding acquisition: KO, YL, GL, SO, and TK. All authors have read and agreed to the published version of the manuscript.</p>
</sec>
</body>
<back>
<sec id="s9" sec-type="funding-information">
<title>Funding</title>
<p>This research was supported by the Japan Society for the Promotion of Science KAKENHI (17H04428, 19KK0243, and 21H03221 to SO), Kanazawa University Sakigake Project (to SO), Kanazawa University Overseas Research Support for Young Scientists (to KO), and Takeda Science Foundation Research Grant (to TK).</p>
</sec>
<ack>
<title>Acknowledgments</title>
<p>We thank the staff of the Efoulan district hospital for their collaboration and support, especially Dr. Akame, the HIV clinic coordinator. We also thank the researchers and laboratory staff at the Biotechnology Centre, University of Yaound&#xe9; I, Cameroon, for processing and archiving the samples. We appreciate all the participants of this study for their time and contribution.</p>
</ack>
<sec id="s10" sec-type="COI-statement">
<title>Conflict of interest</title>
<p>KO belongs to the Department of Bio-engineering Nursing, which was funded by Saraya Co., Ltd. Osaka, Japan, from April 1, 2023. The funder was not involved in any stage of this study, and thus does not constitute any conflict of interest on this study.</p>
<p>The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
<sec id="s11" sec-type="disclaimer">
<title>Publisher&#x2019;s note</title>
<p>All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.</p>
</sec>
<sec id="s12" sec-type="supplementary-material">
<title>Supplementary material</title>
<p>The Supplementary Material for this article can be found online at: <ext-link ext-link-type="uri" xlink:href="https://www.frontiersin.org/articles/10.3389/fcimb.2023.1211899/full#supplementary-material">https://www.frontiersin.org/articles/10.3389/fcimb.2023.1211899/full#supplementary-material</ext-link>
</p>
<supplementary-material xlink:href="DataSheet_1.docx" id="SM1" mimetype="application/vnd.openxmlformats-officedocument.wordprocessingml.document"/>
<supplementary-material xlink:href="Table_1.xlsx" id="ST1" mimetype="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"/>
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