Web of Science (WOS) is a highly utilized scholarly database containing over 12,000 influential journals (Wu et al., 2021b) and widely acknowledged as the most comprehensive and reliable database for bibliometric analysis compared to other resources, such as Scopus and PubMed (Sun et al., 2022). Previous studies have shown that Web of Science Core Collection database (WOSCC) is the most suitable repository for bibliometric studies among those that fulfill the requirements for global-level analysis (Deng et al., 2020; Yeung, 2019). In the current study, the relevant literature was searched and exported on 17 January 2024. The time period considered was 1 January 2000 to 31 December 2023, when selected papers and review papers were downloaded. Meeting Abstract, Early Access, Book Chapters, Editorial Material, Proceeding Paper, Letter, Correction, Note and News Item were excluded. The language restriction was English. A total of 4,873 articles were retrieved, among which 1,163 were excluded. The remaining 3,710 articles were exported in plain text with the file name “download_txt” (Figure 1).

The database advanced search entry is set as the following: TS = (“TDM” OR “Drug Monitoring” OR “Monitoring Drug” OR “Therapeutic Drug Monitoring” OR “Drug Monitoring Therapeutic” OR “Monitoring Therapeutic Drug” OR “target concentration intervention” OR “target concentration strategy” OR “model-based precision dosing”) AND TS = (“Anti-Bacterial Agents” OR “Agents Anti-Bacterial” OR “Anti Bacterial Agents” OR “Antibacterial Agents” OR “Agents Antibacterial” OR “Antibacterial Agent” OR “Agent Antibacterial” OR “Anti-Bacterial Compounds” OR “Anti Bacterial Compounds” OR “Compounds Anti-Bacterial” OR “Anti-Bacterial Agent” OR “Agent Anti-Bacterial” OR “Anti Bacterial Agent” OR “Anti-Bacterial Compound” OR “Anti Bacterial Compound” OR “Compound Anti-Bacterial” OR “Bacteriocidal Agents” OR “Agents Bacteriocidal” OR “Bacteriocidal Agent” OR “Agent Bacteriocidal” OR “bactericide” OR “Anti-Mycobacterial Agents” OR “bacteriocines” OR “Agents Anti-Mycobacterial” OR “Anti Mycobacterial Agents” OR “Anti-Mycobacterial Agent” OR “Agent Anti-Mycobacterial” OR “Anti Mycobacterial Agent” OR “Antimycobacterial Agent” OR “Agent Antimycobacterial” OR “Antimycobacterial Agents” OR “Agents Antimycobacterial” OR “Antibiotic” OR “Antibiotics” OR “Infections” OR “Infection” OR “meropenem” OR “vancomycin” OR “piperacillin” OR “ceftazidime” OR “cefepime” OR “gentamicin” OR “tazobactam” OR “piperacillin-tazobactam” OR “ciprofloxacin” OR “amikacin” OR “ceftriaxone” OR “daptomycin” OR “ertapenem” OR “imipenem” OR “moxifloxacin” OR “voriconazole” OR “colistin” OR “flucloxacillin” OR “tobramycin” OR “clarithromycin” OR “amoxicillin” OR “levofloxacin” OR “cilastatin” OR “polymyxin-b” OR “teicoplanin” OR “trimethoprim-sulfamethoxazole” OR “adriamycin” OR “amphotericin-b” OR “ampicillin” OR “cefotaxime” OR “carbapenems” OR “caspofungin” OR “ceftaroline fosamil” OR “cefazolin”).

CiteSpace is a web-based Java application for analysis and visualization of co-citation networks (Chen, 2004). CiteSpace research uses information contained in the articles to evaluate and predict future developments in the field (Liu et al., 2019). The main distinguishing feature of CiteSpace is the use of a diverse, time-phased and dynamic visualization language for citation analysis, showing evolution of the field on a knowledge map of the citation network through a clever spatial layout (Chen et al., 2010). The automatic identification of research frontiers with citation node literature and co-citation clustering as the knowledge base reflects the interpretability of the graph. In this study, CiteSpace 6.3.R1 (Advanced) was used to analyze and visualize the research hotspots and evolution of antimicrobial drugs in TDM since the twenty-first century and predict future trends in the field.

VOSviewer presents a means to construct author or journal maps based on citation data or keyword maps based on co-occurrence data (Wu et al., 2022). The program provides a viewer that enables detailed examination of bibliometric maps. VOSviewer can display maps in numerous ways that highlight different aspects (van Eck and Waltman, 2010), including network, coverage, and density maps, with each focusing on a distinct dimension. The features of VOSviewer are particularly well suited for displaying large bibliometric charts in an understandable format (van Eck and Waltman, 2010). We initially analyzed the major journals, co-cited journals, and co-occurring keywords according to the WOS data using VOSviewer 1.6.20 and subsequently created related network and density maps. The structure of scientific research, research hotspots, and development trends in this field were identified through relevant analyses.

A total of 3,710 relevant papers published between 2000 and 2023 were collected, the number of articles related to antimicrobial drugs and TDM showed a clear upward trend, indicating that this topic continues to attract considerable research attention (Figure 2). Among these, the maximum number of 453 articles were published in 2023.

All the included studies were summarized according to study type and population type, as shown in Figure 3. The number of prospective articles (n = 108) was less than that of retrospective articles (n = 292), both of which focus more on critically ill patients and children (Figure 3A). There are more PK articles (n = 406) than PK/PD articles (n = 151) (Figure 3C), and more articles on safety (n = 109) than efficacy (n = 77) (Figure 3D).

As shown in Figure 4, we screened the top 25 specific drug species from all the keywords. Vancomycin (n = 606), voriconazole (n = 355), meropenem (n = 182), posaconazole (n = 138), gentamicin (n = 133), itraconazole (n = 98), piperacillin (n = 97), amikacin (n = 88), fluconazole (n = 81), and teicoplanin (n = 80) were among the top drug-related keywords.

The countries studied in this field geographically span six continents, notably: North America (USA, Canada), Asia (China, Japan, Korea, India, Iran), Oceania (Australia), Europe (France, Italy, Netherlands, Germany, England, Belgium, Switzerland, Spain, Sweden, Austria), South America (Brazil), and Africa (Egypt), as shown in Figure 5A.

As shown in Figure 5B, the tree wheel history represents the record of published articles from a given country. Different colors of the tree wheel represent the corresponding time and the overall size reflects the number of publications originating from the country. The United States, France, England, and Germany are displayed as purple outer rings, which are characterized by a high degree of centrality (≥0.1) and often considered to be important turning points leading to revolutionary discoveries. Figure 5C displays the number of articles per country/region for the top twenty countries. The United States had the highest number of publications (n = 794), followed by China (n = 406), Australia (n = 363), France (n = 346), Italy (n = 310), Japan (n = 303), the Netherlands (n = 301), Germany (n = 283), and England (n = 212), among others.

We further observed the network of institutional collaborations on the topic of TDM of antimicrobial drugs (Figure 6A). Among the top 20 institutions (Figure 6B), the highest number of publications was produced by the University of Queensland (n = 173), followed by Institut National de la Sante et de la Recherche Medicale (Inserm) (n = 160), Royal Brisbane & Women’s Hospital, the Paris City University (n = 137), Universite Paris Cite (n = 130), Assistance Publique Hopitaux Paris (APHP) (n = 125), NSW Health (n = 115), etc.

In Figure 7, a time series graph was created based on the number of agency publications. Institut National de la Sante et de la Recherche Medicale (France), University of Queensland (Australia), and CHU de Nimes (France), the number of publications from these three institutions is constantly increasing, and there will still be sustained output in this field in the future.

A total of 3,710 articles published in 819 journals were identified. The names of the top 10 journals in terms of number of publications are presented in Table 1. Therapeutic Drug Monitoring had the highest publication rate, followed by Antimicrobial Agents and Chemotherapy, Journal of Antimicrobial Chemotherapy, International Journal of Antimicrobial Agents, and Antibiotics-Basel. Among the top 10 journals, six belonged to JCR Q1.

In the analysis of co-cited journals, 21 had more than 1,000 co-citations out of 12,733 journals. Table 2 displays the top 10 journal names in terms of number of cited papers. Antimicrobial Agents and Chemotherapy had the highest number of co-citations, two of which had an IF ≥ 5, with six journals belonging to JCR Q1.

The Journal biplot overlay depicts the distribution of topics in academic journals, with citing journals displayed on the left and cited journals on the right (Figure 8). The different colored paths indicate the citation relationship. Two green and one yellow citation paths were mainly identified. Citing journals are known as ‘research frontiers’ and cited journals as ‘knowledge bases’. As shown in Figure 8, articles published in Molecular/Biology/Immunology journals primarily cited articles from Molecular/Biology/Genetics journals while articles published in Medicine/Medical/Clinical journals mainly cited articles from Molecular/Biology/Genetics and Health/Nursing/Medicine journals.

Keyword co-occurrence analysis revealed a total of 9,180 keywords, with 1,232 keywords co-occurring ≥5 times that were utilized to generate a keyword co-occurrence map (Figure 9).

In the network analysis diagram, keywords were divided into five clusters, with high correlations within each cluster (Figure 9). The largest clusters, shown in red, comprised 456 terms with a co-occurrence of ≥300 and were related to therapeutic drug monitoring, pharmacokinetics, vancomycin, pharmacodynamics, antibiotics and critically-ill patients. The second cluster is green and contains 220 terms with 7 co-occurrences ≥100, from highest to lowest being voriconazole, safety, management, invasive fungal-infections, posaconazole and aspergillosis. The third cluster is yellow, which contains 155 terms, with 6 co-occurrences ≥100, from highest to lowest being plasma, human plasma, performance liquid-chromatography, serum, quantification, validation. The fourth cluster is pink and contains a total of 108 terms, with 6 co-occurrences ≥30, which in descending order are hiv, treatment failure, antiretroviral therapy, indinavir and ritonavir. The fifth cluster is blue and contains 84 terms, with 4 co-occurrences ≥30, from highest to lowest being infection, tuberculosis, mycobacterium-tuberculosis, and cord factor.

To demonstrate the changes in research hotspots during different time periods, we divided the included literature into four periods, Figure 10 shows the top 20 hotness rankings of keywords and the changes of rankings during different time periods. Vancomycin has seen an increase in its ranking across the four time periods, eventually overtaking voriconazole in the 2012–2017 period. Additionally, since the 2012–2017 period, critically ill patients entered the top 5.

Our analysis of co-cited references revealed that the top 10 were cited a total of 1,053 co-citations and two (Abdul-Aziz et al., 2020; Rybak et al., 2020; Abdul-Aziz et al., 2020; Rybak et al., 2020) had ≥100 co-citations (Table 3). The most co-cited reference was published by Abdul-Aziz MH in Intensive Care Medicine in 2020 (Abdul-Aziz et al., 2020).

The co-cited literature was analyzed for keyword clustering (Figure 11). Different colors represent the clusters to which different co-cited studies belong and the same colors indicate a close relationship between different co-cited studies. In terms of the connecting lines between clusters, the initial direction (depicted in blue) evolved from the direction of red arrows. As shown in the figure, keyword clustering resulted in division of the co-cited studies into nine categories. The first three clusters were voriconazole, posaconazole and vancomycin.

CiteSpace co-citation burst analysis was used, with the burst duration of co-cited studies set to a minimum of 2 years. A total of 446 co-citations showed bursts and the studies with the strongest citation bursts were selected (Figure 12). Overall, 24% (6/25) of references showed citation bursts in 2008, followed by 16% (4/25) in 2015. In 2021–2023, “Antimicrobial therapeutic drug monitoring in critically ill adult patients: a Position Paper” (Abdul-Aziz et al., 2020) published in Intensive Care Medicine by Abdul-Aziz MH, was the most explosive (strength = 71.86), consistent with results of the co-citation literature analysis. As shown in Table 4, the top 25 co-cited literatures were analyzed according to the dynamics and intensity of the burst, and the research hotspots were identified by analyzing the time trends.