BackgroundPseudomonas aeruginosa is a major human pathogen, which also affects animals. It is thought that P. aeruginosa has a non-clonal epidemic population structure, with distinct isolates found in humans, animals or the environment. However, very little is known about the structure of the P. aeruginosa population from diseased animals. Data on antimicrobial resistance are also scarce.ResultsThirty-four already registered and 19 new MLST profiles were identified. Interestingly, a few clones were more prevalent, and clones associated to human outbreaks were also detected. Multidrug resistance phenotypes were overall rare.ConclusionWe highlight the non clonal structure of the population and show a higher prevalence of specific clones, possibly correlating with higher pathogenicity. The low proportion of antimicrobial resistance contrasts with the high resistance rate of human isolates.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0324-x) contains supplementary material, which is available to authorized users.

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Most ESBL-producing E. cloacae from animals studied here (69.4%) belonged to potentially high-risk clones in humans, in particular ST114 (44.4%). These data raise questions and potential concerns about the transfer of E. cloacae between animals and humans.

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Drinking water has rarely been recognized as a source of antimicrobial resistance for humans, and only in low-income countries. Here, a sequence type 48 Escherichia coli isolate carrying the bla CTX-M-1 IncI1/ST3 plasmid was recovered from drinking water in France. This plasmid was similar to other bla CTX-M-1 IncI1/ST3 plasmids found previously in animals and humans. Our findings highlight the possible human transfer of extended-spectrum ␤-lactamase (ESBL) genes through drinking water in high-income countries.E xtended-spectrum ␤-lactamases (ESBLs) are widespread enzymes that confer resistance to broad-spectrum cephalosporins. ESBL genes are mostly located on plasmids, which play key roles in horizontal transfer of the genes. Consumption of ESBL-contaminated foodstuff or contacts with ESBL-colonized/infected animals enhance the risk of human transfer of ESBL genes from nonhuman sources. ESBLs have also been found in soils and rivers polluted by human or animal waste, such as hospital sewage or runoff from land occupied by livestock. Drinking water is also a source of human contamination with waterborne pathogens and/or antimicrobial-resistant bacteria. However, reports of drinking water contaminated with ESBL-producing organisms are scarce (1-3).Here, we describe an ESBL-positive Escherichia coli isolate (isolate 32420) recovered in 2011 from a 100-ml water sample collected after treatment from an old (Ͼ30-year-old) water supply located at the periphery of a city in northeastern France. Drinking water samples were collected from 28 water supplies throughout France between December 2011 and April 2012. Water supplies were selected on the basis of repeated quality failures, i.e., detection of coliforms, over the previous 3 years. Twenty-six supplies were small, serving fewer than 2,000 people, whereas two served around 10,000 people. Water treatment before distribution included disinfection with chlorine in the smallest water supplies or sand filtration, coagulation with aluminum, and a final chlorine dioxide treatment in larger supplies collecting water from rivers.One-liter water samples were collected in sterile bottles containing sodium thiosulfate, at the point at which drinking water enters the distribution system or at a point of consumption. Samples were preserved in ice boxes and transported to the ANSES Nancy laboratory, where 100 ml was analyzed by membrane filtration and growth on selective media (4) to determine the presence of coliforms. E. coli isolates (n ϭ 67) (confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry [MALDI-TOF MS]) were detected in all samples, with counts ranging from 1 to 45 CFU/100 ml. None of the isolates was considered virulent, since stx 1 , stx 2 , and eae genes were absent. All isolates were tested for antimicrobial susceptibility to 32 antibiotics by disk diffusion, according to the Antibiogram Committee of the French Society for Microbiology guidelines (www.sfm-microbiologie.org), and 6 E. coli isolates from 6 different water supplies w...