Introduction
Healthcare-associated infections (HAIs) impose substantial physical, social, and economic burdens on hospitalized patients. Most HAIs originate from the patient’s endogenous flora; however, a substantial proportion result from contamination within the healthcare environment Reference Kanamori, Rutala and Weber1 . Over the past decades, it has become increasingly evident that fomites, including patient care items and environmental surfaces, are frequently contaminated and can serve as reservoirs or sources of pathogens Reference Kanamori, Rutala and Weber1 . Outbreaks caused by fomites can be effectively prevented through the implementation of appropriate infection prevention practices, such as proper hand hygiene and adequate disinfection of hospital surfaces Reference Kanamori, Rutala and Weber1,Reference Weber, Rutala and Sickbert-Bennett2 . Germicides, including antiseptics (germicides applied to the skin or mucous membranes to reduce microbial flora) and disinfectants (germicides applied to inanimate objects to reduce/eliminate pathogens), play a pivotal role in preventing such outbreaks Reference Weber, Rutala and Sickbert-Bennett2 . However, germicides themselves can become contaminated and serve as a source of outbreaks Reference Weber, Rutala and Sickbert-Bennett2 . We previously reviewed outbreaks linked to contaminated antiseptics and disinfectants in 2007, identifying 58 reports published from 1958 to 2005 Reference Weber, Rutala and Sickbert-Bennett2 . Many of these incidents were caused by user errors, including the use of expired products, over-dilution of antiseptics and disinfectants, dilution with tap water, refilling small-volume dispensers from large-volume stock containers, and improper selection of the appropriate product. In the last 20 years since that review numerous regulations and guidelines have been established for the proper use of antiseptics and disinfectants Reference Rutala and Weber3 ; however, many additional outbreaks resulting from contaminated antiseptics and disinfectants have been published. In this study, we conducted a literature review of outbreaks and pseudo-outbreaks linked to contaminated antiseptics and disinfectants reported after 2006 aiming to clarify the reasons for the continued occurrence of these outbreaks by presenting their characteristics and to propose new prevention strategies.
Materials and methods
This scoping review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) (Supplementary material). We searched the published literature (January 2006–June 2024) via the PubMed database using the following Medical Subject Heading (MeSH) and keywords: (hospital OR hospitals OR hospital units OR nursing homes OR ambulatory care facilities OR ambulatory care OR dental facilities OR assisted living facilities OR healthcare settings OR patient) AND (outbreak OR disease outbreak OR healthcare-associated infection OR nosocomial OR cross infection) AND (germicide OR antiseptics OR disinfectants OR alcohols OR chlorhexidine OR iodine OR iodophors OR quaternary ammonium compounds OR triclosan OR glutaral OR glutaraldehyde OR formaldehyde OR phenol OR phenols OR phenolics) AND contamination. Identified articles were initially screened based on their title and abstract for potential inclusion. Pseudo-outbreaks, defined as the recovery of the same organism from the cultures of patients who are neither infected nor colonized with the organism, were included. Articles addressing outbreaks caused by contaminated pharmaceuticals other than disinfectants, such as contact lens solutions, those addressing outbreaks resulting from contamination of endoscopes and ultrasound probes, those occurred in non-medical setting (e.g., prisons), articles not involving human infections, non-English-language articles, and review articles were excluded. Eligible articles were then assessed through full-text review. Additionally, we identified further relevant articles by reviewing the reference lists of review articles identified through our literature search, that described outbreaks associated with contaminated antiseptics and disinfectants.
Results
Overview
A total of 2,307 publications were identified through our PubMed literature search, of which 2,212 included abstracts (Figure 1). After excluding duplicates, 2,210 references were screened based on titles and abstracts, resulting in the exclusion of 2,163 references. The remaining 47 articles underwent full-text review. Of these, twenty articles reporting cases of contamination that did not describe the type of contaminated antiseptics or disinfectant were excluded. No additional article identified through the review of reference list of two relevant review articles Reference Yoon, Kim, Lim and Kang4,Reference Häfliger, Atkinson and Marschall5 . Ultimately, the remaining 27 articles were included in this review.
Figure 1. Flow chart of the review process.
Twenty-one distinct outbreaks and 4 pseudo-outbreaks were reported in 23 and 4 articles, respectively, associated with contaminated antiseptics and disinfectants globally from 2006 to 2023 (Table 1 and 2). The number of publications increased after 2020 (Figure 2). All outbreaks and pseudo-outbreaks were caused by bacteria; none by viruses, fungi or parasites. Outbreaks occurred in all six World Health Organization (WHO) regions, except for the South-East Asian Region. Four outbreaks (19%) occurred in intensive care units (ICU) Reference Bilgin, Altınkanat Gelmez and Bayrakdar6–Reference Becker, Berger and Feldner9 , two each (10%) in hematology wards Reference Lanini, D’Arezzo and Puro10,Reference Fanci, Bartolozzi and Sergi11 and dialysis wards Reference Vázquez Castellanos, Copado Villagrana, Torres Mendoza, Gallegos Durazo, González Plascencia and Mejía-Zárate12,Reference Lo Cascio, Bonora and Zorzi13 , one each (5%) in an oncology ward Reference Heo, Kim, Jeong, Bae, Jin and Lee14 , a pediatric oncology and hematology ward Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15 , a neonatal ICU Reference Molina-Cabrillana, Santana-Reyes, González-García, Bordes-Benítez and Horcajada16 , or an oriental medical clinic Reference Koh, Song and Kang17 . Five each (24%) outbreaks occurred across multiple wards within a single hospital Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18–Reference Dolan, Littlehorn and Glodé22 , and occurred across multiple hospitals Reference Lo Cascio, Bonora and Zorzi13,Reference Leong, Lagana and Carter23–Reference de Frutos, López-Urrutia and Domínguez-Gil28 .
Table1. Outbreaks due to contaminated antiseptics and disinfectants
Abbreviations; CHG, chlorhexidine; CLABSI, central line-associated bloodstream infection; CRBSI, catheter-related blood stream infection; ICU, intensive care unit; MDR, multidrug resistant; NA, not available; QAC, quaternary ammonium compounds; SCT, stem cell transplantation; SSTI, skin and soft tissue infection; VAP, ventilator-associated pneumonia.
Table 2. Pseudo-outbreaks due to contaminated antiseptics and disinfectants
Abbreviations; CHG, chlorhexidine; MDR, multidrug resistant; NA, not available; QAC, quaternary ammonium compounds.
Figure 2. Trend of outbreaks and pseudo-outbreaks associated with contaminated antiseptics and disinfectants by 5-year period of publication.
In 17 out of the 21 outbreaks (81%), contaminated antiseptics caused infections through their direct use on patients. Seven (41%) were attributed to contamination of chlorhexidine (CHG) Reference Bilgin, Altınkanat Gelmez and Bayrakdar6–Reference dos Santos Saalfeld, Shinohara and dos Anjos Szczerepa8,Reference Al Zunitan, Aldawood and El-Saed21,Reference Leong, Lagana and Carter23 , quaternary ammonium compounds (QAC) Reference Kutty, Moody and Gullion26 or octanidine Reference Becker, Berger and Feldner9 mouthwash, which were used for oral hygiene care aimed at preventing ventilator-associated pneumonia in intubated patients. Six outbreaks resulted in skin and soft tissue infections or catheter-related infections in patients from contaminated CHG (n = 5) or alcohol-based skin antiseptic (n = 1) that were then used for preoperative skin preparation Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18,Reference Dolan, Littlehorn and Glodé22 and surgical wound care Reference Clara, Staneloni and Salazar19 , procedural skin preparation prior to vascular Reference Heo, Kim, Jeong, Bae, Jin and Lee14,Reference Merino, Bouarich and Pita25,Reference Fernández, Adrio, Martínez Cereijo, Martínez Monzonis, El-Diasty and Alvarez Escudero27,Reference de Frutos, López-Urrutia and Domínguez-Gil28 , peritoneal Reference Wong, Wong and Chen24 , or urinary Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18 catheter insertion and maintenance, or for obtaining blood cultures Reference Merino, Bouarich and Pita25,Reference Fernández, Adrio, Martínez Cereijo, Martínez Monzonis, El-Diasty and Alvarez Escudero27,Reference de Frutos, López-Urrutia and Domínguez-Gil28 . In two outbreaks (14%), infections occurred indirectly in patients through the hands of healthcare personnel who became contaminated by washing their hands with contaminated antiseptic soap Reference Lanini, D’Arezzo and Puro10,Reference Fanci, Bartolozzi and Sergi11 . In three out of the 21 outbreaks (14%), contaminated disinfectants indirectly caused infections in patients by contaminating surfaces in patients’ rooms and medication preparation rooms Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15 , or via central venous catheters for dialysis Reference Lo Cascio, Bonora and Zorzi13 or physical therapy devices Reference Koh, Song and Kang17 . A median of 13 individuals (range: 3–256) developed infection and a median of 0 individual (range: 0–29) died because of these outbreaks.
Of the four pseudo-outbreaks, one was reported in a neonatal ICU Reference Song, Kwak and Um29 and multiple wards within a single hospital Reference Ko30 in South Korea, one in a hematology ward in France Reference Siebor, Llanes and Lafon31 , and one in an ICU in Germany Reference Günther, Merle, Frank, Gaida and Mutters32 . Two instances were attributed to contamination of CHG skin antiseptics used during blood drawing Reference Song, Kwak and Um29,Reference Ko30 , while the remaining two resulted from contamination of the blood culture bottles placed on contaminated trays from a contaminated disinfectant Reference Siebor, Llanes and Lafon31,Reference Günther, Merle, Frank, Gaida and Mutters32 . A median of 24 patients (range: 19–40) were misdiagnosed with bacteremia and subsequently received unnecessary antimicrobial treatment.
Type of contaminated antiseptics/disinfectant and associated bacteria
Among the twenty-one outbreaks, seventeen (81%) were linked to low-level disinfectants including CHG, QAC, and diluted (1%) glutaraldehyde Reference Rutala and Weber3 (Table 1). Contaminated CHG was the most frequently reported source of outbreaks, accounting for 12 out of 21 instances (57%). Of these, more than half (8 out of 12 outbreaks, 67%) were associated with Burkholderia spp., while the remaining outbreaks included three (25%) by Achromobacter spp. and one (8%) by S. marcescens. The contaminated CHG solutions were used at various concentrations, ranging from a 0.12% mouthwash Reference Zurita, Mejia and Zapata7,Reference dos Santos Saalfeld, Shinohara and dos Anjos Szczerepa8 to a 4% soap solution applied to surgical wounds Reference Clara, Staneloni and Salazar19 . Burkholderia cepacia and S. marcescens contaminated 2% solutions Reference Bilgin, Altınkanat Gelmez and Bayrakdar6,Reference Fernández, Adrio, Martínez Cereijo, Martínez Monzonis, El-Diasty and Alvarez Escudero27,Reference de Frutos, López-Urrutia and Domínguez-Gil28 , while Achromobacter spp. contaminated a 4% solution Reference Clara, Staneloni and Salazar19 . Outbreaks due to contaminated QAC were the second most common, accounting for 4 out of 21 outbreaks (19%). Two (50%) were caused by contamination of didecyl-dimethyl-ammonium chloride solutions with Achromobacter sp. Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15 and Burkholderia cenocepacia Reference Lo Cascio, Bonora and Zorzi13 , respectively. One each (25%) was caused by contamination of a benzalkonium chloride solution with Achromobacter spp. Reference Vázquez Castellanos, Copado Villagrana, Torres Mendoza, Gallegos Durazo, González Plascencia and Mejía-Zárate12 and an antiseptic mouthwash solution containing cetylpyridinium chloride with B. cenocepacia Reference Kutty, Moody and Gullion26 .
In most of the articles reviewed in this study, it was not specified whether the contaminated antiseptic and disinfectant solutions were aqueous or alcohol-based. However, at least one outbreak (5%) was linked to alcohol pledgets packaged with 70% isopropyl alcohol contaminated with Bacillus cereus Reference Dolan, Littlehorn and Glodé22 . The remaining three (14%) were linked to other antiseptics: two were associated with triclosan-containing soap contaminated with Pseudomonas aeruginosa Reference Lanini, D’Arezzo and Puro10,Reference Fanci, Bartolozzi and Sergi11 , and one was associated with octenidine mouthwash contaminated with B. cepacia complex Reference Becker, Berger and Feldner9 .
Of the four pseudo-outbreaks, two (50%) were associated with 0.5% CHG solutions contaminated with Burkholderia spp. Reference Song, Kwak and Um29,Reference Ko30 (Table 2). One (25%) was linked to 0.25% QAC solutions contaminated with Achromobacter xylosoxidans, Comamonas testosteroni, Pseudomonas fluorescens, Stenotrophomonas maltophilia Reference Siebor, Llanes and Lafon31 . The remaining one (25%) was attributed to glucoprotamin, a newer active compound for disinfectant Reference Meinke, Meyer, Frei, Passweg and Widmer33 , contaminated with A. xylosoxidans Reference Günther, Merle, Frank, Gaida and Mutters32 . No reports of outbreaks or pseudo-outbreaks associated with contaminated iodine or iodophors were identified.
Of the 21 outbreaks and 4 pseudo-outbreaks, 11 (52%) and 2 (50%), respectively, provided data on the susceptibility of the causative bacteria. Of these, one associated with a pseudo-outbreak Reference Song, Kwak and Um29 was classified as multidrug-resistant Reference Magiorakos, Srinivasan and Carey34 . Of the 25 outbreaks/pseudo-outbreaks, fifteen (60%) applied pulsed field gel electrophoresis Reference Bilgin, Altınkanat Gelmez and Bayrakdar6,Reference Lanini, D’Arezzo and Puro10,Reference Lo Cascio, Bonora and Zorzi13–Reference Koh, Song and Kang17,Reference Lee, Han, Kim, Song, Lee and Kwon20,Reference Dolan, Littlehorn and Glodé22,Reference Kutty, Moody and Gullion26,Reference Fernández, Adrio, Martínez Cereijo, Martínez Monzonis, El-Diasty and Alvarez Escudero27,Reference Song, Kwak and Um29–Reference Günther, Merle, Frank, Gaida and Mutters32 , eight (32%) applied conventional PCR methods Reference dos Santos Saalfeld, Shinohara and dos Anjos Szczerepa8,Reference Lanini, D’Arezzo and Puro10,Reference Fanci, Bartolozzi and Sergi11,Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15,Reference Koh, Song and Kang17,Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18,Reference Dolan, Littlehorn and Glodé22,Reference Kutty, Moody and Gullion26,Reference Günther, Merle, Frank, Gaida and Mutters32 , three each (12%) applied multilocus sequence typing Reference Zurita, Mejia and Zapata7,Reference Lanini, D’Arezzo and Puro10,Reference Clara, Staneloni and Salazar19 and whole genome sequencing (WGS)-based typing Reference Becker, Berger and Feldner9,Reference Leong, Lagana and Carter23,Reference Wong, Wong and Chen24 , and one (4%) applied matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based typing Reference Fernández, Adrio, Martínez Cereijo, Martínez Monzonis, El-Diasty and Alvarez Escudero27 for typing the causative microorganism.
Intrinsic and extrinsic contamination
Contamination of the antiseptic used in 13 out of 21 (62%) outbreaks and in 2 out of 4 (50%) pseudo-outbreaks occurred during manufacturing or transport (intrinsic contamination) Reference Weber, Rutala and Sickbert-Bennett2 (Table 1 and 2). All five outbreaks involving multiple hospitals were caused by intrinsically contaminated products Reference Lo Cascio, Bonora and Zorzi13,Reference Leong, Lagana and Carter23–Reference Kutty, Moody and Gullion26 . Of the outbreaks identified in this review, the largest was attributed to the intrinsically contaminated 0.05% CHG solution with B. cepacia complex Reference Wong, Wong and Chen24 . This solution, used for the care of peritoneal dialysis catheter exit sites, caused catheter-related infections in 256 patients across multiple hospital in Hong Kong and resulted in four deaths. The outbreak associated with the largest number of deaths (n = 29) was caused by the intrinsically contaminated 0.2% CHG mouthwash in multiple wards in a single hospital in Saudi Arabia Reference Al Zunitan, Aldawood and El-Saed21 . After the cause was identified, the contaminated product was removed or recalled in all cases. In 13 out of 15 (87%) instances, the authorities or the manufacturer were notified, and the notification led to prohibition on the use of the product Reference Merino, Bouarich and Pita25,Reference Fernández, Adrio, Martínez Cereijo, Martínez Monzonis, El-Diasty and Alvarez Escudero27,Reference de Frutos, López-Urrutia and Domínguez-Gil28 , manufacturer prohibited from manufacturing Reference Dolan, Littlehorn and Glodé22 , and reclassification of CHG skin antiseptic as pharmaceutical products Reference Wong, Wong and Chen24 . There was no mention of notifications to authorities or the manufacturer in the remaining two outbreaks Reference Bilgin, Altınkanat Gelmez and Bayrakdar6,Reference Lo Cascio, Bonora and Zorzi13 . Only two cases (13%) described the mechanism of product contamination: one attributed to contamination of the water used in the manufacturing process Reference Leong, Lagana and Carter23 and the other due to contamination of the semi-automated packing machine Reference Wong, Wong and Chen24 .
Contamination of the antiseptics and disinfectants used in 7 out of 21 (33%) outbreaks Reference Lanini, D’Arezzo and Puro10,Reference Fanci, Bartolozzi and Sergi11,Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15–Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18,Reference Lee, Han, Kim, Song, Lee and Kwon20 and in 2 out of 4 (50%) pseudo-outbreaks occurred during manipulation or use in medical facilities (extrinsic contamination) Reference Weber, Rutala and Sickbert-Bennett2 . In the remaining one outbreak, it was not specified whether the contamination of the antiseptic was intrinsic or extrinsic Reference Heo, Kim, Jeong, Bae, Jin and Lee14 . All of the instances due to extrinsic contamination of antiseptics and disinfectants were associated with improper practices, including failure to follow appropriate dilution methods or concentrations for disinfectants Reference Koh, Song and Kang17 , using tap water or non-sterile water for dilution Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15,Reference Koh, Song and Kang17,Reference Lee, Han, Kim, Song, Lee and Kwon20 , leaving prepared disinfectants for extended periods Reference Molina-Cabrillana, Santana-Reyes, González-García, Bordes-Benítez and Horcajada16,Reference Koh, Song and Kang17 , refilling small-volume dispensers from large-volume containers Reference Lanini, D’Arezzo and Puro10,Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15,Reference Molina-Cabrillana, Santana-Reyes, González-García, Bordes-Benítez and Horcajada16,Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18 , improper dispenser maintenance Reference Siebor, Llanes and Lafon31,Reference Günther, Merle, Frank, Gaida and Mutters32 , and selection of inappropriate products, such as triclosan in human hygiene products Reference Lanini, D’Arezzo and Puro10,Reference Fanci, Bartolozzi and Sergi11 . Several authorities, including the United States Food and Drug Administration and the European Chemicals Agency, have banned triclosan in human hygiene products due to insufficient evidence of its safety and efficacy in reducing infections Reference Halden, Lindeman and Aiello35 . Of the nine outbreaks and pseudo-outbreaks due to extrinsic contamination, five (56%) presumably caused by contamination of water, either tap water Reference Fanci, Bartolozzi and Sergi11,Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15–Reference Koh, Song and Kang17 or non-sterile purified water from purification system Reference Lee, Han, Kim, Song, Lee and Kwon20 . In two of these instances, interventions involved using sterile water to prepare disinfectant solutions Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15,Reference Lee, Han, Kim, Song, Lee and Kwon20 , and in one instance, interventions included replacing taps, installation of the water filters, and hyperchlorination of water network were taken Reference Fanci, Bartolozzi and Sergi11 . In two instances each, the dispensers were disinfected or replaced Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18,Reference Günther, Merle, Frank, Gaida and Mutters32 , and the containers of disinfectant solution and atomizers were removed Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15,Reference Molina-Cabrillana, Santana-Reyes, González-García, Bordes-Benítez and Horcajada16 . In one instance, the use of a solution prepared in the hospital laboratory was prohibited Reference Lee, Han, Kim, Song, Lee and Kwon20 . In an outbreak caused by contaminated CHG solution used for skin antisepsis to clean wounds and abrasions, and as a disinfectant prior to urinary catheterization, interventions were implemented to replace the solution with pre-made solutions to clean wounds and sterile water for urinary chaterization Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18 . In an outbreak caused by contaminated soap dispenser, interventions were implemented to use soap-dispenser provided with disposable cartridges and to prioritize the use alcohol-based handrub Reference Lanini, D’Arezzo and Puro10 .
Discussion
Our review revealed that numerous bacterial outbreaks and pseudo-outbreaks associated with contaminated antiseptics and disinfectants have been increasingly reported in healthcare institutions worldwide since 2006. More outbreaks and pseudo-outbreaks have likely occurred than those reported in the literature, as suggested by the higher number of product recalls due to microbial contamination Reference States Food and Administration36 . Most of the reported outbreaks were due to the direct use of contaminated mouthwashes and skin antiseptics on patients, leading to a substantial number of infections including ventilator-associated pneumonia, skin and soft tissue infections or catheter-related infections which resulted in 55 fatalities. Sixty-two percent of the outbreaks were attributed to intrinsically contaminated antiseptics or disinfectants, while 38% were attributed to extrinsically contaminated ones. Most outbreaks were resolved by removing the contaminated products and implementing changes in the preparation, storage, usage, or application procedures after the source of contamination was identified.
Most outbreaks were attributed to contamination of CHG being the most frequently reported, followed by QAC. Outbreaks associated with CHG have shown an increasing trend compared to the 32% (13/41) reported in our previous review in 2007Reference Weber, Rutala and Sickbert-Bennett 2 . CHG and QAC have seen increasing application in various medical settings over the years. CHG is commonly used as an antiseptic for pre-operative skin antiseptic, skin antisepsis in ICUs, as well as oral care and patient bathing, and QAC is utilized as disinfectant for medical devices and surfaces, due to their safety and tolerability Reference Van den Poel, Saegeman and Schuermans37,Reference Boyce38 . CHG and QAC demonstrate broad-spectrum germicidal activity; however, the most common pathogens responsible for outbreaks identified in this study, Burkholderia spp., Achromobacter spp., and S. marcescens, may exhibit reduced susceptibility to CHG and QAC, and are capable surviving and multiplying in these solutions at concentrations used clinically as antiseptics or disinfectants or higher (0.12–4% for CHG and 0.02–1.6% for QAC) Reference Van den Poel, Saegeman and Schuermans37,Reference Boyce38 . Outbreaks caused by contaminated alcohol-based products are rare because alcohols exhibit broad-spectrum antimicrobial activity against various bacteria including Burkholderiales and S. marcescens Reference Rutala and Weber3 ; however, these products can become contaminated with Bacillus spp., which are spore-forming bacteria capable of surviving in antiseptic solutions, including 70% alcohol Reference Dolan, Littlehorn and Glodé22 . Similarly, iodine and iodophors possess broad-spectrum antimicrobial properties, and outbreaks due to their contamination are also uncommon Reference Weber, Rutala and Sickbert-Bennett2,Reference Rutala and Weber3 . Nevertheless, there have been documented cases of outbreaks associated with intrinsically contaminated products, particularly involving Burkholderia cepacia and Pseudomonas aeruginosa Reference Weber, Rutala and Sickbert-Bennett2 . Although antiseptics/disinfectants can be potential sources of contamination, identifying them as the cause of an ongoing outbreak can be challenging due to their inherent antimicrobial properties. Infectious disease physicians and infection preventionists should be vigilant about potential of pathogens capable of contaminating antiseptics or disinfectants. Highly accurate microbial typing methods, such as WGS-based and MALDI-TOF MS-based typing, which has advanced significantly in recent years, can be useful in investigations of potentially contaminated antiseptics and disinfectants Reference Wong, Wong and Chen24,Reference Fernández, Adrio, Martínez Cereijo, Martínez Monzonis, El-Diasty and Alvarez Escudero27 .
More than half of the outbreaks were attributed to intrinsically contaminated mouthwash and other antiseptic products, contrasting with the findings of Weber et al. in 2007, who reported that most outbreak cases resulted from extrinsic contamination of antiseptics and disinfectants due to user error Reference Weber, Rutala and Sickbert-Bennett2 . Sterile drug products require stringent aseptic handling and sterilization throughout their manufacturing processes Reference States Food and Administration39 : however, most antiseptic and disinfectant products used in healthcare are labeled as non-sterile, permitting a limited level of bacterial contamination Reference Dolan, Littlehorn and Glodé22 . The pathogens responsible for the outbreaks, including Burkholderia spp., S. marcescens, and Achromobacter spp., are recognized as important opportunistic pathogens causing invasive nosocomial infections; therefore, products that are not guaranteed to be sterile should be avoided for use on wounds, compromised mucosal surfaces, catheter exit sites, and in patients at high risk of opportunistic infections, including critically ill patients, cancer patients, dialysis patients, and neonates to prevent outbreaks caused by intrinsically contaminated antiseptic or disinfectant products Reference Wong, Wong and Chen24 . In addition, intrinsically contaminated products should be promptly removed with notification of the relevant authorities and the manufacturer to prevent further infections which may lead to product recall, manufacturing prohibition, and/or regulatory changes regarding the offending antiseptic or disinfectant.
Outbreaks resulting from extrinsic contamination of disinfectants, accounting for approximately one-third of all instances, were attributed entirely to improper practices Reference Weber, Rutala and Sickbert-Bennett2 . Many errors occurred in the preparation and storage of disinfectants in hospitals and other facilities, including diluting disinfectants with non-sterile water, leaving prepared disinfectants for extended periods, and refilling dispensers from containers. Hospital water and water-related devices including taps, dispensers, and atomizers can act as a reservoir of waterborne pathogens in healthcare settings Reference Kanamori, Rutala and Weber1,Reference Kanamori, Weber and Rutala40 . Therefore, to prevent extrinsic contamination of antiseptics and disinfectants, hospitals should avoid preparing these solutions on-site and instead ideally use pre-made solutions. If on-site preparation is unavoidable, sterile water should be used for the dilution of antiseptics and disinfectants instead of tap water, which may contain environmental bacteria, including Achromobacterspp. Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15,Reference Molina-Cabrillana, Santana-Reyes, González-García, Bordes-Benítez and Horcajada16 , P. aeruginosa Reference Fanci, Bartolozzi and Sergi11 , and mycobacteria Reference Koh, Song and Kang17 , particularly when these agents are applied to critical surfaces or non-intact skin. Solutions should be diluted and stored as indicated on the product label. Dispensers and containers should be strictly monitored to ensure proper functioning, correct usage, and disinfection according to manufacturer’s recommendations Reference Weber, Rutala and Sickbert-Bennett2,Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18,Reference Siebor, Llanes and Lafon31,Reference Cadnum, Kaple and Eckstein41 . When tap water is used to rinse the dispenser or container of a disinfectant, the potential for contamination should be taken into consideration Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15,Reference Molina-Cabrillana, Santana-Reyes, González-García, Bordes-Benítez and Horcajada16,Reference Günther, Merle, Frank, Gaida and Mutters32 . If possible, unnecessary dispensers, containers, and atomizers must be removed Reference Hugon, Marchandin, Poirée, Fosse and Sirvent15,Reference Molina-Cabrillana, Santana-Reyes, González-García, Bordes-Benítez and Horcajada16,Reference Said, Mitton, Skosana, Kopotsa, Naidoo and Amutenya18,Reference Günther, Merle, Frank, Gaida and Mutters32 . To prevent outbreaks associated with contaminated soap, refilling soap dispensers should be avoided Reference Kanamori, Rutala and Weber1 . Since CHG-containing soap is prone to contamination by nosocomial pathogens, the WHO recommends using alcohol-based hand rub instead of CHG-containing soap Reference Van den Poel, Saegeman and Schuermans37 .
Conclusions
We reviewed outbreaks and pseudo-outbreaks linked to contaminated antiseptics and disinfectants and summarized the current characteristics of them and infection control and prevention. Although this review is not a systematic review using systematic methods to synthesize findings of studies in accordance with the PRISMA 2020 statement Reference Page, McKenzie and Bossuyt42 , we believe it provides a broad overview of the available evidence. Since we limited our literature search to PubMed to focus on peer-reviewed outbreak reports with sufficient detail for comparison, outbreaks reported only in conference abstracts or unpublished sources were not included; however, we reviewed more than 2,200 articles, which we believe is sufficient for the purpose of a scoping review. Outbreaks resulting from extrinsically or intrinsically contaminated antiseptics and disinfectants persist globally, presenting a substantial risk of HAI to patients; however, most of these outbreaks can be prevented through the correct use of antiseptics and disinfectants on appropriate targets, as well as proper practices in preparation and storage. To overcome the contamination problems, all healthcare personnel should receive education to the potential risk of infection associated with inappropriate practices.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/ice.2025.10242
