In pediatric populations, the presence of this microorganism is strongly linked to hospital environments where moisture, invasive devices and repeated airway manipulation support its persistence. A review that compiled 86 pediatric cases attributed to Ralstonia species found that R. pickettii accounted for 81.4%, exceeding R. mannitolilytica (15.1%) and R. insidiosa (3.4%) (2). This pattern is consistent with clinical ecology studies that have documented its presence in hospital water systems, contaminated solutions and respiratory equipment, confirming its preference for humid, nutrient-poor environments (12). Environmental and clinical investigations have reported recovery rates of up to 10% from respiratory samples and hospital devices, reinforcing its ability to persist in healthcare settings (13). Outside the pediatric context, low but recurrent isolation has been reported in blood cultures from units with frequent invasive manipulation, suggesting environmental circulation in complex clinical environments (14). These findings indicate that high-complexity pediatric services, particularly those relying on intensive respiratory support, represent the settings where exposure to Ralstonia is most likely (15, 16).

Studies in tracheostomized children provide additional insight into its epidemiological behavior. These cohorts show exogenous acquisition in respiratory cultures obtained after the procedure, even when initial samples were negative, demonstrating the presence of active environmental reservoirs in ventilatory equipment exposed to continuous humidity (17). This observation aligns with changes documented in respiratory microbiota during prolonged ventilation, where colonization reflects the microbiological characteristics of the environment rather than the patient's baseline flora (18).

Reports in neonates offer key information on more severe presentations associated with this microorganism. In several episodes of early-onset sepsis, blood culture isolation was linked to exposure to clinical products that were later shown to be contaminated, predominantly affecting premature infants with immunological immaturity and dependence on invasive devices (19, 20). This pattern is consistent with a neonatal outbreak in which five very preterm infants were colonized after endotracheal instillation of contaminated saline; the investigation demonstrated intrinsic contamination in up to 65% of vials, highlighting the organism's ability to withstand manufacturing processes and spread through standardized clinical products (21). Additional evidence from high-humidity environments, such as burn units, shows that R. pickettii can appear in open wounds manipulated with moist materials, although at low frequencies, reinforcing its link to hydrated surfaces and materials (22). These scenarios illustrate the difficulty of early reservoir identification in neonatal units, where multiple inputs can function as silent vectors of transmission (23).

In neonatal care, the relationship between infection and invasive devices is a consistent finding. Recent manipulation of catheters, respiratory circuits or infusion systems often precedes clinical deterioration, supporting their role as vectors of transmission (24, 25). This evidence is reinforced by a multicenter pediatric outbreak in which 34 patients, most of them children, acquired R. pickettii through contaminated saline used in irrigation and humidification procedures; molecular analysis confirmed clonal identity among cases, establishing this as one of the largest outbreaks associated with the genus (26). The importance of humid devices as reservoirs is further supported by a prematurity-associated outbreak caused by R. mannitolilytica, where reused humidifiers allowed bacterial persistence in internal cartridges and tubing, demonstrating that heating and humidification systems can harbor environmental bacilli despite standard cleaning procedures (27). These findings are consistent with cohorts showing that respiratory circuits can function as persistent reservoirs capable of sustaining colonization for weeks (28).

From an environmental perspective, Ralstonia species exhibit notable survival in low-nutrient aqueous solutions and can form biofilms that resist standard cleaning procedures, which explains the prolonged duration of outbreaks involving respiratory and humidification equipment used in pediatrics (2). Microbiological studies confirm that these organisms establish dense, highly resistant biofilms on plastic surfaces, water distribution systems and equipment exposed to prolonged moisture, even after repeated disinfection cycles (12). In settings where contaminated reservoirs are integrated into centralized humidification or internal water distribution systems, spread can extend to general hospitalization areas outside critical care (29). Prolonged viability has also been demonstrated under environmental conditions that resemble devices routinely used in children, supporting its potential to sustain nosocomial transmission despite standard cleaning and maintenance protocols (30).

The ability of Ralstonia pickettii to persist in clinical environments is supported by its affinity for water systems, capacity to form biofilm and genomic features that promote tolerance to disinfectants and stress conditions. Its presence has been documented in water networks, presumed sterile solutions, humidifiers and complex medical devices, facilitated by mechanisms that include chlorhexidine resistance, passage through 0.2 μm filters and a repertoire of environmental adaptation genes (2, 31–33). This stability is reflected in outbreaks linked to intravenous solutions, heparin, irrigation fluids and contaminated production water, where the organism has demonstrated the ability to bypass filtration systems and persist across entire industrial batches (7, 21, 27, 34–37). These characteristics explain why outbreaks associated with contaminated solutions arise both from manufacturing failures and from prolonged accumulation within storage tanks or distribution systems, leading to transmission through irrigation procedures, nebulization or clinical rinsing solutions (38, 39). Detection of the microorganism in moisture-prone points of water networks and on surfaces of extracorporeal devices confirms that residual humidity can act as a persistent reservoir even outside pharmaceutical products (40, 41).

In devices containing internal water circuits, the combination of stagnant water, structural defects and repeated handling promotes surface colonization and dispersion to vascular or respiratory lines. In pediatric ECMO units, genomic concordance between environmental and clinical isolates confirmed this route, illustrating that even equipment subjected to routine checks can act as reservoirs when residual moisture persists (33, 42). Similar outbreaks have been reported in humidification systems and extracorporeal devices, where internal biofilm accumulation enabled recurrent contamination despite standardized cleaning procedures (27, 35, 37, 41). Additional cases have been linked to heparinized syringes and vascular solutions in which intrinsic contamination introduced the organism directly into the bloodstream, even when aseptic technique was appropriate (7, 43).

Respiratory devices represent another important route. In ventilated neonates and tracheostomized children, tubing, humidifiers and valves have been shown to transfer environmental bacteria into the lower airway, particularly in the presence of vulnerable stomas or repeated interventions. The detection of exogenous colonization by Pseudomonas pickettii, now recognized as Ralstonia pickettii, in patients with no compatible baseline flora confirms that respiratory equipment can serve as a direct bridge between the environment and the host (17, 28, 44). This risk has appeared in outbreaks involving contaminated endotracheal instillation solutions, which introduced the organism into the airway and facilitated spread through ventilatory circuits (26). High-flow systems and humidification equipment have also harbored persistent biofilm, with documented transmission between devices and patients even after disinfection protocols were applied (27, 37, 45). The presence of environmental nonfermenting organisms in intensive care settings and high-humidity environments supports the ease with which these bacteria spread through aerosols or wet surfaces, favoring cross-colonization events (8, 22, 46, 47).

In immunocompromised patients, exposure to contaminated intravenous solutions or irrigation systems can lead to rapid progression to sepsis, particularly when long-term catheters are in place (48). Transmission has also been linked to peritoneal solutions, urinary irrigation systems and previously colonized catheters, where accumulated biofilm allows reinoculation of the bloodstream or mucosal surfaces in vulnerable hosts (49). Environmental introduction can also manifest as clinical colonization without a clear epidemiological link, highlighting the influence of host susceptibility in infection expression (50–52). The identification of Ralstonia in the intestinal microbiota of hospitalized patients suggests that the host may become a secondary reservoir, contributing to environmental circulation and complicating infection control (53).

Confirmation of these transmission routes depends on accurate diagnostic tools. MALDI-TOF combined with genomic sequencing allows differentiation of true outbreaks from pseudobreaks, reconstruction of transmission chains and attribution of origin to medical products, water systems, devices or the host, which is essential for pathogens with multiple potential reservoirs (2, 54). These techniques have demonstrated clonal relationships between clinical and environmental isolates across outbreaks and have ruled out erroneous sources through comparative analysis of genomic profiles and pulsed-field patterns, improving accuracy in identifying environmental reservoirs and failures in manufacturing or reprocessing (38). The available evidence indicates that transmission of R. pickettii in clinical environments arises from the convergence of water reservoirs, colonized devices and host susceptibility, a scenario that requires ongoing environmental surveillance and integrated control strategies.

The pathogenicity of Ralstonia pickettii results from a coordinated set of cellular and molecular mechanisms that support environmental persistence, adhesion to abiotic surfaces and human epithelium, tissue colonization and activation of host inflammatory pathways.

Clinical manifestations of infections caused by Ralstonia species vary by age, immune status and mode of acquisition. Reported cases range from critically ill neonates to adolescents with severe central nervous system involvement, producing a broad clinical spectrum summarized in Table 1.

Identification of Ralstonia species in pediatric settings remains difficult because of their close phenotypic similarity to other non-fermenting Gram-negative bacilli and the limited resolution of routine diagnostic systems. Conventional platforms such as API 20NE, RapID NF Plus and VITEK 2 often produce inconsistent results that classify isolates as Alcaligenes, Comamonas, Pseudomonas or unrelated organisms. These errors become more frequent when growth is slow or scant, which reinforces early assumptions of contamination and delays microbiological confirmation (25, 27, 34, 72–74).

Similar limitations occur in respiratory samples from children, particularly in cystic fibrosis, where complex microbiota and heterogeneous tissue compromise culture yield and lead to discrepancies with molecular testing. Ralstonia may be detected by sequencing without growing in culture because of low biomass, overgrowth by dominant flora or irregular distribution within lung tissue (16, 29, 61).

Reduced biochemical profiles and the use of limited identification panels further contribute to misclassification, as documented in outbreaks where isolates were misidentified due to incomplete sugar panels or restricted discriminatory capacity of automated systems (38, 46, 50). Taxonomic proximity to the Burkholderia cepacia complex, Pandoraea, Achromobacter and Stenotrophomonas explains the frequent misidentification of R. pickettii, R. mannitolilytica and R. insidiosa. These species share overlapping biochemical profiles and similar behavior on conventional and selective media, including growth on agar formulated for BCC or failure to grow on media intended for these species. This produces both false positives and false negatives and complicates interpretation in children with chronic respiratory disease (51, 75–77).

Historical nomenclature such as Burkholderia pickettii adds further ambiguity in blood cultures and catheter samples, making it harder to distinguish infection, colonization and contamination and contributing to diagnostic delays in multiple pediatric outbreaks (15, 23, 52, 78, 79). Surveillance studies have shown that Ralstonia can coexist with other structurally similar nonfermenters, which leads to misassignment in laboratories with outdated databases (80).

Molecular methods improve diagnostic precision but have limitations when used alone. The 16S rRNA gene shows more than 98% identity across Ralstonia species, which reduces discriminatory capacity and explains ambiguous reads and culture-sequencing discrepancies in low-biomass samples. Species-specific PCRs may miss recently described species or closely related phylogroups that appear only in broad Burkholderia-Ralstonia-Pandoraea assays, creating false negatives in laboratories reliant on narrow panels and necessitating genotypic confirmation (16, 61, 72, 73, 81). This issue has been documented in outbreaks where VITEK 2 misidentified R. mannitolilytica as R. pickettii, corrected only after 16S sequencing or updated MALDI-TOF analysis, demonstrating that automated systems can fail at both genus and species levels (45, 50). Heterogeneous antimicrobial susceptibility patterns among related isolates add confusion and limit the utility of phenotypic profiles for inferring clonality (38, 46).

The ability of Ralstonia to contaminate solutions, equipment, respiratory devices, sterile-labelled vials and hospital water systems creates pseudobacteremias and false outbreaks that closely resemble true infection. Its capacity to pass through 0.2 µm filters, persist within resistant biofilms and survive at low bacterial loads explains initial negative cultures followed by later positive results that appear clinically meaningful (27, 34, 37, 47, 74). In several events, cultures of unopened vials confirmed intrinsic contamination of the product while patients remained clinically stable, which prolonged uncertainty around the clinical relevance of isolates and led to either unnecessary interventions or delayed identification of the true source (47, 78). Similar findings have been reported in Vapotherm devices, where reappearance of Ralstonia after disinfection and without clinical use indicated that biofilm maturity determines cleaning effectiveness and can generate false negative results following reprocessing (37). In individual cases, single positive catheter cultures or isolated blood cultures were dismissed as contamination despite compatible clinical findings, illustrating that low-level isolation remains a persistent source of diagnostic error (14, 45, 49, 52, 66).

The evidence shows that diagnostic accuracy depends on integrating phenotypic and molecular tools with careful clinical evaluation. The absence of standardized procedures for prolonged culture, variable interpretation of selective media, incomplete or outdated laboratory databases, contamination-related outbreaks, and overlapping biochemical patterns challenge the ability of laboratories to distinguish contamination, colonization and true infection. These factors support the need for combined approaches that minimize false positives and false negatives and strengthen surveillance and clinical management in pediatric practice (15, 70, 78, 82).

Available studies show that Ralstonia species display a susceptibility profile marked by intrinsic resistance to many beta lactams and aminoglycosides, variable activity of fluoroquinolones and trimethoprim sulfamethoxazole, and the presence of mechanisms such as chromosomal OXA beta lactamases, efflux pumps and qnr genes (83, 84). Descriptive series report consistent resistance to ceftazidime, cefepime, piperacillin tazobactam and aztreonam, with inconsistent carbapenem activity influenced by local antimicrobial pressure (85). In pediatric settings, Ralstonia is uncommon but follows patterns similar to other nonfermenters, with in-creasing aztreonam resistance and partial fluoroquinolone activity (86). Detection of ESBL and AmpC in expanded microbiological analyses further limits the usefulness of cephalosporins for empirical therapy (86). These observations parallel reports from settings such as cystic fibrosis and burn units, where multidrug resistant phenotypes predominate (22, 40, 80).

Clinical reports reinforce this heterogeneity. One R. mannitolilytica isolate showed extensive resistance to cephalosporins, carbapenems and aminoglycosides, with activity restricted to levofloxacin, trimethoprim sulfamethoxazole and tigecycline (83). In contrast, a case of R. pickettii meningitis showed broad susceptibility and a favorable response to ceftriaxone (58). In a neonatal cohort, resistance to imipenem and meropenem was accompanied by preserved activity only for ciprofloxacin (60). Recurrent infections linked to catheters or dialysis systems showed progressive resistance and biofilm formation, contributing to therapeutic failure until device removal (9, 49). These recurrences have also been associated with polyclonal infections, which explain inter isolate variability even within the same patient (45, 66).

Outbreak investigations provide additional insight into susceptibility patterns. In a hemodialysis unit, R. mannitolilytica showed uniform resistance to third generation cephalosporins, piperacillin tazobactam and meropenem, attributed to expression of OXA 22 and OXA 60, with variable fluoroquinolone and trimethoprim sulfamethoxazole activity (35). During epidemics linked to contaminated water or solutions, R. pickettii displayed heterogeneous susceptibility between biotypes, although regimens such as ceftazidime with ciprofloxacin or combinations including tobramycin were effective when the contaminated source was eliminated (36). Its persistence in aqueous environments and ability to pass through 0.2 µm filters highlight the importance of environmental control alongside targeted therapy (49).

Reported resistance rates include approximately 17% for ciprofloxacin, 26% for trimethoprim sulfamethoxazole, 30 to 40% for third generation cephalosporins, 45% for piperacillin tazobactam, 60% for aztreonam, more than 60% for aminoglycosides and up to 38% for imipenem. These figures reflect a restricted therapeutic spectrum influenced by OXA 60 expression (5). Clinical response does not always correlate with in vitro activity, and catheter or source removal is often required for resolution (7).

Despite these limitations, some agents retain value in selected cases, including ciprofloxacin, levofloxacin, trimethoprim sulfa-methoxazole and, in defined situations, tigecycline (60, 83, 84). Favorable ceftriaxone response in a pediatric meningitis case should not be generalized without microbiological support (58). Treatment should always follow the individual susceptibility profile, avoiding empirical use of third generation cephalosporins or carbapenems in children without strong microbiological justification. Accurate diagnosis, reliable susceptibility testing and proper source management, including removal of contaminated devices, form the most effective strategy to improve outcomes in pediatric Ralstonia infections.

Pediatric outbreaks caused by Ralstonia species share a central feature: intrinsic contamination of hospital supplies, particularly distilled water and aqueous chlorhexidine solutions used in neonatal and intensive care units (18, 87). The organism persists in water based environments and forms biofilm within distribution systems and preparation containers, which allows silent trans-mission across multiple units without clear spatial linkage (87). This dynamic explains clusters of positive blood cultures emerging across different wards within short intervals, often without clear clinical signs of sepsis, which complicates early detection and delays institutional response (87).

Local preparation of antiseptic solutions has been identified as a critical vulnerability. In several outbreaks, distilled water processed through contaminated resins and large batch preparation of chlorhexidine facilitated dissemination of the same clonal strain across pediatric areas (87, 88). This risk is heightened in neonatal units, where immature immunity and frequent use of invasive devices create conditions favorable for colonization and infection. Fulminant sepsis in an extremely premature infant illustrates this vulnerability, even when a specific environmental source is not immediately identified (57). Coexistence of asymptomatic colonization and absence of clear clinical criteria in many infants further contributes to underdiagnosis and hinders active surveillance (88).

Outbreak investigations show that combining antimicrobial susceptibility profiles with genotypic tools such as RAPD has been essential to confirm clonal relationships and reconstruct transmission routes. Correlation between molecular profiles and susceptibility patterns linked patient blood cultures directly to contaminated batches of chlorhexidine and distilled water prepared in hospital pharmacy settings (87, 88). This evidence supported a focused response aimed at the true source based on consistent microbiological data.

The most effective interventions included immediate replacement of contaminated solutions, adoption of safer purification methods such as reverse osmosis, use of single dose chlorhexidine presentations, review of pharmacy and nursing procedures and expansion of surveillance in affected units (18, 87, 88). These measures-controlled outbreaks and prevented recurrence, reinforcing the importance of prevention strategies centered on identifying and correcting contamination sources.

In resource-limited settings, Ralstonia pickettii assumes particular epidemiological relevance, as structural conditions favor both its emergence and persistence. Multiple outbreaks have shown that local preparation of solutions, reliance on hospital water systems with irregular control, and limited traceability of medical supplies increase the risk of intrinsic contamination and sustained exposure (10, 87, 88). In these contexts, detection is often delayed, since advanced microbiological identification is not routinely available and early events may be misinterpreted as isolated contamination or transient colonization (4). Consequently, outbreaks may spread silently across critical care units before being recognized, with substantial clinical impact on vulnerable populations, especially pediatric and immunocompromised patients (11, 26). These experiences suggest that, beyond its intrinsically low virulence, R. pickettii behaves as an emerging pathogen in systems with structural limitations, where microbiological surveillance, environmental control, and regulatory response face operational barriers that delay effective containment.