OBJECTIVE: To assess the residual risk of waterborne contamination by Pseudomonas aeruginosa (PA) from water network colonized by a single genotype (Sequence Type (ST)299) despite the presence of antimicrobial filters in a medical intensive care unit (ICU). METHODS: During the first 19-month period after ICU opening, water network contamination was assessed monthly by collecting water upstream the filters. Downstream water was also sampled to assess filters efficiency. PA clinical isolates from patients were collected and compared to the waterborne ST299-PA by multiplex-rep PCR, Pulsed-Field Gel Electrophoresis (PFGE) and whole-genome sequencing. Cross-transmission events occurring independently of the genotype of PA involved were also assessed. RESULTS: From 449 samples of filtered water, 1.3% were positive for PA in inoculum varying between 1 to 104 Colony Forming Unit (CFU)/100mL according to the tap. All PA hydric isolates belonged to PA-ST299 and displayed <2 Single Nucleotide Polymorphisms (SNPs). Among 278 clinical isolates from 122 patients, 10 isolates in 5 patients showed identical profiles to the hydric PA-ST299 clone in both multiplex-rep PCR and PFGE and differed by <5 SNPs on average, confirming the water network reservoir as the source of contamination by PA for 4.09% of patients. Cross-transmission events by other genotypes of PA than PA-ST299 were responsible for the contamination of 1.75 % of patients. DISCUSSION/CONCLUSION: Antimicrobial filters are not sufficient to preserve patients from waterborne pathogens when the water network is highly contaminated. The microbiological survey of filtered water may be needed in units hosting at-risk patients for PA infections, even when all water points-of-use are protected by filters.
To investigate the capacities of persistence and dissemination of blaNDM-5 within Escherichia coli and in aquatic environment, we characterized E. coli (sequence type 636) strains B26 and B28 isolated one month apart from the same urban river in Montpellier, France. The two isolates carried a pTsB26 plasmid, which sized 45,495 Kb, harbored blaNDM-5 gene and belonged to IncX-3 incompatibility group. pTsB26 was conjugative in vitro at high frequency, it was highly stable after 400 generations and it exerted no fitness cost on its host. blaNDM-5harboring plasmids are widely dispersed in E. coli all around the world, with no lineage specialization. The genomic comparison between B26 and B28 stated that the two isolates probably originated from the same clone, suggesting the persistence of pTsB26 in an E. coli host in aquatic environment.
The hospital environment constitutes a reservoir of opportunistic pathogens responsible for healthcare-associated infections (HCAI) such as Pseudomonas aeruginosa (Pa). Pa persistence within technological niches, the increasing emergence of epidemic high-risk clones in HCAI, the epidemiological link between plumbing strains and clinical strains, make it a major nosocomial pathogen. Therefore, understanding the mechanisms of Pa adaptation to hospital water systems would be useful in preventing HCAI. This review deciphers how copper resistance contributes to Pa adaptation and persistence in a hospital environment, especially within copper water systems, and ultimately to its success as a causative agent of HCAI. Numerous factors are involved in copper homeostasis in Pa, among which active efflux conferring copper tolerance, and copper-binding proteins regulating the copper compartmentalization between periplasm and cytoplasm. The functional harmony of copper homeostasis is regulated by several transcriptional regulators. The genomic island GI-7 appeared as especially responsible for the copper resistance in Pa. Mechanisms of copper and antibiotic cross-resistance and co-resistance are also identified, with potential co-regulation processes between them. Finally, copper resistance of Pa confers selective advantages in colonizing and persisting in hospital environments but also appears as an asset at the host/pathogen interface that helps in HCAI occurrence.
Cross Infection , Pseudomonas aeruginosa , Copper/metabolism , Hospitals , Humans , Pseudomonas aeruginosa/genetics , Water
Non-tuberculous mycobacteria (NTM) are opportunistic pathogens commonly colonizing hospital water systems, and may be responsible for healthcare-associated infections (HAI). Investigation of HAI and outbreaks caused by NTM necessitates water analyses. However, NTM are slow-growing bacteria within the mesophilic community present in water, and are difficult to detect. Prior to culture on specific media, their recovery usually requires decontamination and concentration steps. We assessed the effectiveness of filtration as regards the recovery of 7 NTM species in hospital water samples. We also compared the use of cetylpyridinium chloride (CPC) at different concentrations and Sodium Hydroxide (NaOH) 4% in decontamination of water samples with mesophilic bacteria. Our laboratory protocol showed that membrane filtration was suitable for concentration and recovery of NTM from water. Sample decontamination with CPC was more NTM-preservative than NaOH. A combination of CPC at 0.005% and filtration allowed detection of NTM at low concentrations, ranging from 3 to 98 CFU/100mL according to the NTM species.
Cetylpyridinium , Nontuberculous Mycobacteria , Culture Media , Hospitals , Water
Carbapenems are ß-lactams antimicrobials presenting a broad activity spectrum and are considered as last-resort antibiotic. Since the 2000s, carbapenemase producing Enterobacterales (CPE) have emerged and are been quickly globally spreading. The global dissemination of carbapenemase encoding genes (CEG) within clinical relevant bacteria is attributed in part to its location onto mobile genetic elements. During the last decade, carbapenemase producing bacteria have been isolated from non-human sources including the aquatic environment. Aquatic ecosystems are particularly impacted by anthropic activities, which conduce to a bidirectional exchange between aquatic environments and human beings and therefore the aquatic environment may constitute a hub for CPE and CEG. More recently, the isolation of autochtonous aquatic bacteria carrying acquired CEG have been reported and suggest that CEG exchange by horizontal gene transfer occurred between allochtonous and autochtonous bacteria. Hence, aquatic environment plays a central role in persistence, dissemination and emergence of CEG both within environmental ecosystem and human beings, and deserves to be studied with particular attention.
An outbreak means a sudden rise of the incidence of a disease, generally infectious, at a certain place over an extended period of time. The term pandemic is used when an outbreak is spreading on a global scale. By the past, Human has been able to face several pandemics by developing preventive and therapeutic strategies. The new societal and economic behaviour enhance the progression of old and new diseases. The development of new multidisciplinary approaches is necessary to prevent new pandemic episodes.
