Pathogenic Escherichia coli producing Extended-Spectrum β-Lactamases isolated from surface water and wastewater

Dissemination of CTX-M-Producing Escherichia coli in Freshwater Fishes From a French Watershed (Burgundy)

The burden of extended-spectrum β-lactamases producing Escherichia coli (ESBL-Ec), has increased over several decades. Freshwater ecosystems are suspected to play an important ecological and evolutionary role in driving the dissemination of antimicrobial resistance. The aim of our study was to decipher the occurrence of ESBL-Ec in a small watershed (Ouche river, Burgundy, France), targeting environmental matrices and fishes. Among cefotaxime resistant E. coli (ctxR Ec) isolates, we detected and characterized 36 ESBL-Ec from water, biofilm and fish guts. ctxR Ec and ESBL-Ec were found in samples from sites near the first small town, located downstream from the watershed which was studied. Treatment of urban wastewater by waste water treatment plants (WWTP), might therefore be a major potential source of ctxR Ec and thus of ESBL-Ec. Prevalence of total E. coli and ctxR Ec in fish guts ranged between 0 to 92% and 0 to 85%; respectively, depending on the sampling site and the fish species. The diet of fish (predator or omnivore) seems to strongly influence the prevalence of total E. coli and ESBL-Ec. Extended spectrum beta-lactamases produced by the isolates from this study belonged to the CTX-M family (CTX-M group 1 and 9). Moreover, some environmental ESBL-Ec proved to share genotypic features (MLST types) with isolates which originated from 8 WWTP effluents discharged in the Ouche river and with the sequence type ST131, which is widely described in clinical isolates. Ninety-seven % (97%) of ESBL-Ec from the study harbored additional antibiotic resistances and can thus be considered as multi drug resistant (MDR) bacteria. Finally, 53% of the ESBL-Ec strains harbored class 1 integron-integrase (intl1). These results are discussed with the perspective of defining indicators of antibiotic resistance contamination in freshwater ecosystems.

Study on the presence of resistant diarrheagenic pathotypes in Escherichia coli isolated from patients with urinary tract infection

AIM

This article aimed to analyze the diarrheagenic potential of E. coli isolated from urinary tract infection (UTI) and to recognize the presence of antibiotic resistance genes.

BACKGROUND

The marked genome plasticity of Escherichia coli has allowed the emergence of resistant pathogenic strains displaying an unusual arrangement of genes.

METHODS

In this cross-sectional study, 110 E. coli were isolated from patients with the symptoms of UTI in Sanandaj, west of Iran between July and September - 2015. The isolates were examined by the disk diffusion method for antibiotic susceptibility test and by polymerase chain reaction for the presence of genes characteristic of diarrheagenic E. coli (DEC), Uropathogenic E. coli (UPEC) virulence genes, extended-spectrum β-lactamase bla _CTX-M and plasmid-mediated quinolone resistance determinants, qnrA, qnrB, and qnrS.

RESULTS

The most and the least effective antibiotics were nitrofurantoin and cefotaxime (96.4% and 27.3% sensitivity, respectively). Of the 110 UTI isolates, 57.3% carried diarrheagenic genes. The bundle-forming pilus bfpA was the most prevalent diarrheagenic gene (39.1%). The most commonly detected DEC pathotype was enterotoxigenic E. coli (-ETEC, 12.7%). All the pathotypes carried the bla _CTX-M and qnr. The -UPEC hly hemolysin and pap adhesin genes were mainly detected among ETEC isolates.

CONCLUSION

Our results indicated the presence of resistant diarrheagenic pathotypes in UTI-associated E. coli. Such isolates may have the capacity of causing both extraintestinal and intestinal infections. Based on our knowledge, this is the first report of the presence of qnr in ETEC from urine.

Evaluation of virulence factors profiles and antimicrobials resistance of Escherichia coli isolated from bulk tank milk and raw milk filters

Data on the presence of pathogenic Escherichia coli in bulk tank milk (BTM) and raw milk filters (RMF) are not available in Italy and there are few studies worldwide. Therefore, a study under field condition was conducted to assess the presence of E.coli pathogenic and commensal (CoEC) strains in BTM and RMF samples and their associated AMR pattern. One hundred forty-nine E.coli isolates were characterized. Among all the isolates, 53 (35.6%) were classified as pathogenic while the other ones were classified as CoEC. Among the pathogenic ones, 23 (54.7%) were classified as enterotoxigenic E.coli (ETEC), 6 (11.3%) as enteroinvasive E.coli (EIEC), 2 (3.8%) as enteroaggregative E.coli (EAEC), 12 (22.6%) harboured virulence factors (VF) common to ETEC+EIEC, and 2 (3.8%) common to ETEC+EAEC. To our knowledge, it is the first time that ETEC isolates harboring VF associated with EAEC or EIEC are observed in raw milk. These data support the presence of transmission of VFs genes among isolates. None of the isolates showed resistance to three or more antimicrobials. The CoEC role as a vector of AMR was confirmed by the presence of 18% ampicillin- and cephalexin-resistant isolates. The presence of AMR in CoEC supports the role of these bacteria as source of resistance genes. Monitoring raw milk by either BTM or RMF analysis, and the relatively cheap procedure applied to identify E.coli pathotypes can be useful to identify hazards related to the spread of enteric diseases and antimicrobial resistance.

Antimicrobial-Resistant E. coli from Surface Waters in Southwest Ontario Dairy Farms

Untreated surface waters can be contaminated with a variety of bacteria, including , some of which can be pathogenic for both humans and animals. Therefore, such waters need to be treated before their use in dairy operations to mitigate risks to dairy cow health and milk safety. To understand the molecular ecology of , this study aimed to assess antimicrobial resistance (AMR) in recovered from untreated surface water sources of dairy farms. Untreated surface water samples ( = 240) from 15 dairy farms were collected and processed to isolate . A total of 234 isolates were obtained and further characterized for their serotypes and antimicrobial susceptibility. Of the 234 isolates, 71.4% were pan-susceptible, 23.5% were resistant to one or two antimicrobial classes, and 5.1% were resistant to three or more antimicrobial classes. Whole genome sequence analysis of 11 selected multidrug-resistant isolates revealed AMR genes including and that confer resistance to the critically important extended-spectrum cephalosporins, as well as a variety of plasmids (mainly of the replicon type) and class 1 integrons. Phylogenetic and comparative genome analysis revealed a genetic relationship between some of the sequenced and Shiga toxin-producing O157:H7 (STEC), which warrants further investigation. This study shows that untreated surface water sources contain antimicrobial-resistant which may serve as a reservoir of AMR that could be disseminated through horizontal gene transfer. This is another reason why effective water treatment before usage should be routinely done on dairy farm operations.

Study of the In Vitro Antagonistic Activity of Various Single-Strain and Multi-Strain Probiotics against Escherichia coli

Escherichia coli is an important commensal of our gut, however, many pathogenic strains exist, causing various severe infections in the gut or beyond. Due to several antibiotic resistance patterns of E. coli, research of alternative treatments or adjuvant therapy is important. One of these is the use of probiotics as antagonistic agents against E. coli. Most published studies investigate only one strain of E. coli and single-strain probiotics. The objectives of this study were to evaluate the antagonistic activity of selected single-strain and multi-strain probiotic supplements against selected clinical E. coli pathotypes using the in vitro agar spot test and the co-culturing method. Molecular methods were used to determine the presence of the genus lactobacilli and bifidobacteria as well as certain selected strains in the probiotic supplements. The agar-spot test showed that the multi-strain probiotics were more effective than the single-strain probiotics. On the other hand, the co-culturing method showed the opposite result, indicating that results are importantly influenced by the chosen method. The most effective single-strain probiotics against E. coli strains were Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus reuteri DSM 17938. The most effective multi-strain probiotics contained lactobacilli, bifidobacteria and enterococci strains, thus proving that most effective probiotics against E. coli strains are the lactic acid bacteria and bifidobacteria. The overall results from both in vitro tests reveal that all selected probiotics exhibited an antagonistic activity against all E. coli strains. From a public health perspective probiotics have thus proved to be successful in inhibiting the growth of E. coli and could therefore be used as adjuvant therapy or alternative therapy in E. coli infections.

Zoonotic Fecal Pathogens and Antimicrobial Resistance in Canadian Petting Zoos

This study aimed to better understand the potential public health risk associated with zoonotic pathogens in agricultural fairs and petting zoos in Canada. Prevalence of Salmonella, Shiga toxin-producing Escherichia coli (STEC) O157:H7, and top six non-O157 STEC serogroups in feces (n = 88), hide/feather (n = 36), and hand rail samples (n = 46) was assessed, as well as distributions of antimicrobial resistant (AMR) broad and extended-spectrum β-lactamase (ESBL)-producing E. coli. Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in pig nasal swabs (n = 4), and Campylobacter, Cryptosporidium, and Giardia in feces was also assessed. Neither Salmonella nor MRSA were detected. Campylobacter spp. were isolated from 32% of fecal samples. Cryptosporidium and Giardia were detected in 2% and 15% of fecal samples, respectively. Only one fecal sample was positive for STEC O157, whereas 22% were positive for non-O157 STEC. Multi-drug resistance (MDR) to antibiotics classified as critically and highly important in human medicine was proportionally greatest in E. coli from cattle feces. The β-lactamase-producing E. coli from pig, horse/donkey feces, and hand rail samples, as well as the STEC E. coli from handrail swabs were MDR. The diversity and prevalence of zoonotic pathogens and AMR bacteria detected within agricultural fairs and petting zoos emphasize the importance of hygienic practices and sanitization with respect to reducing associated zoonotic risks.

Vaccines Against Escherichia coli

Escherichia coli has a complex and versatile nature and continuously evolves from non-virulent isolates to highly pathogenic strains causing severe diseases and outbreaks. Broadly protective vaccines against pathogenic E. coli are not available and the rising in both, multi-drug resistant and hypervirulent isolates, raise concern for healthcare and require continuous efforts in epidemiologic surveillance and disease monitoring. The evolving knowledge on E. coli pathogenesis mechanisms and on the mediated immune response following infection or vaccination, together with advances in the "omics" technologies, is opening new perspectives toward the design and development of effective and innovative E. coli vaccines.

Risk of Transmission of Antimicrobial Resistant Escherichia coli from Commercial Broiler and Free-Range Retail Chicken in India

Multidrug-resistant Escherichia coli infections are a growing public health concern. This study analyzed the possibility of contamination of commercial poultry meat (broiler and free-range) with pathogenic and or multi-resistant E. coli in retail chain poultry meat markets in India. We analyzed 168 E. coli isolates from broiler and free-range retail poultry (meat/ceca) sampled over a wide geographical area, for their antimicrobial sensitivity, phylogenetic groupings, virulence determinants, extended-spectrum-β-lactamase (ESBL) genotypes, fingerprinting by Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR and genetic relatedness to human pathogenic E. coli using whole genome sequencing (WGS). The prevalence rates of ESBL producing E. coli among broiler chicken were: meat 46%; ceca 40%. Whereas, those for free range chicken were: meat 15%; ceca 30%. E. coli from broiler and free-range chicken exhibited varied prevalence rates for multi-drug resistance (meat 68%; ceca 64% and meat 8%; ceca 26%, respectively) and extraintestinal pathogenic E. coli (ExPEC) contamination (5 and 0%, respectively). WGS analysis confirmed two globally emergent human pathogenic lineages of E. coli, namely the ST131 (H30-Rx subclone) and ST117 among our poultry E. coli isolates. These results suggest that commercial poultry meat is not only an indirect public health risk by being a possible carrier of non-pathogenic multi-drug resistant (MDR)-E. coli, but could as well be the carrier of human E. coli pathotypes. Further, the free-range chicken appears to carry low risk of contamination with antimicrobial resistant and extraintestinal pathogenic E. coli (ExPEC). Overall, these observations reinforce the understanding that poultry meat in the retail chain could possibly be contaminated by MDR and/or pathogenic E. coli.

A comparison of extended spectrum β-lactamase producing Escherichia coli from clinical, recreational water and wastewater samples associated in time and location

Extended spectrum β-lactamase producing Escherichia coli (ESBL-EC) are excreted via effluents and sewage into the environment where they can re-contaminate humans and animals. The aim of this observational study was to detect and quantify ESBL-EC in recreational water and wastewater, and perform a genetic and phenotypic comparative analysis of the environmental strains with geographically associated human urinary ESBL-EC. Recreational fresh- and saltwater samples from four different beaches and wastewater samples from a nearby sewage plant were filtered and cultured on differential and ESBL-selective media. After antimicrobial susceptibility testing and multi-locus variable number of tandem repeats assay (MLVA), selected ESBL-EC strains from recreational water were characterized by whole genome sequencing (WGS) and compared to wastewater and human urine isolates from people living in the same area. We detected ESBL-EC in recreational water samples on 8/20 occasions (40%), representing all sites. The ratio of ESBL-EC to total number of E. coli colony forming units varied from 0 to 3.8%. ESBL-EC were present in all wastewater samples in ratios of 0.56-0.75%. ST131 was most prevalent in urine and wastewater samples, while ST10 dominated in water samples. Eight STs and identical ESBL-EC MLVA-types were detected in all compartments. Clinical ESBL-EC isolates were more likely to be multidrug-resistant (p<0.001). This study confirms that ESBL-EC, including those that are capable of causing human infection, are present in recreational waters where there is a potential for human exposure and subsequent gut colonisation and infection in bathers. Multidrug-resistant E. coli strains are present in urban aquatic environments even in countries where antibiotic consumption in both humans and animals is highly restricted.

Detection and drug resistance profile of Escherichia coli from subclinical mastitis cows and water supply in dairy farms in Saraburi Province, Thailand

Subclinical mastitis is a persistent problem in dairy farms worldwide. Environmental Escherichia coli is the bacterium predominantly responsible for this condition. In Thailand, subclinical mastitis in dairy cows is usually treated with various antibiotics, which could lead to antibiotic resistance in bacteria. E. coli is also a reservoir of many antibiotic resistance genes, which can be conveyed to other bacteria. In this study, the presence of E. coli in milk and water samples was reported, among which enteropathogenic E. coli was predominant, followed by enteroaggregative E. coli and enterohemorrhagic E. coli, which was found only in milk samples. Twenty-one patterns of antibiotic resistance were identified in this study. Ampicillin- and carbenicillin-resistant E. coli was the most common among the bacterial isolates from water samples. Meanwhile, resistance to ampicillin, carbenicillin, and sulfamethoxazole-trimethoprim was the pattern found most commonly in the E. coli from milk samples. Notably, only the E. coli from water samples possessed ESBL phenotype and carried antibiotic resistance genes, bla_TEM and bla_CMY-2. This indicates that pathogenic E. coli in dairy farms is also exposed to antibiotics and could potentially transfer these genes to other pathogenic bacteria under certain conditions.

Targeting the gram-negative bacteria peptidoglycan synthase MraY as a new approach for monoclonal antibody anti-bacterial activity

The use of antibiotics to target bacteria is a well-validated approach for controlling infections in animals and humans. Peptidoglycan biosynthesis is a crucial process in bacteria, and the conserved peptidoglycan synthase MraY is an attractive target for drug design. However, due to the lack of detailed MraY structural information, antibiotics targeting MraY have not yet been developed. In the present study, 2 hydrophilic regions of MraY from Escherichia coli were expressed as a fusion protein and used to raise a monoclonal antibody in mice. We confirmed that the MraY amino acid sequence PESHFSKRGTPT forms the core epitope recognized by the monoclonal antibody M-H11. Furthermore, our results show that M-H11 effectively controls Escherichia coli BL21 (DE3) plysS infection, both in vitro and in vivo. Our results may be of great value in the search for novel approaches used to control bacterial infections.

A nitrocefin-based amperometric assay for the rapid quantification of extended-spectrum β-lactamase-producing Escherichia coli in wastewaters

A sensitive and inexpensive amperometric assay based on the electrochemical detection of the β-lactamase activity using the nitrocefin as substrate was developed for the rapid and quantitative detection of extended spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) in urban wastewaters. The specific detection of ESBL-EC was achieved by culturing the filtered sample in a medium containing the cefotaxime supplemented or not with the potassium clavulanate inhibitor. This step was followed by the incubation of each subculture filtrate with the nitrocefin substrate which hydrolysis was monitored by amperometry using disposable carbon screen-printed sensors. Current intensities i_Cef and i_Clav correspond to the intensity of the anodic current measured (∼+ 0.2 V vs. Ag/AgCl) for the sample incubated with the cefotaxime without and with potassium clavulanate, respectively. The intensity value i = i_Cef - i_Clav was chosen as the analytical response. ESBL-EC calibration plots were established with artificially contaminated wastewater samples. This assay allowed the detection of ESBL-EC amounts as low as 10 cfu in treated effluents and 100 cfu in raw wastewaters with short time analysis of 5.5 h and 4.5 h, respectively. The amperometric method was applied to the analysis of 38 wastewater samples and the results were in good agreement with CFU counts on a selective chromogenic medium for 24 h. Owing to its rapidity, convenience, low-cost and portability, this assay is a promising tool to obtain quantitative data on antimicrobial-resistant E. coli in wastewater effluents. Furthermore, this assay might be used to improve wastewater treatment plant processes in order to minimize the release of antibiotic resistant bacteria into the aquatic environment.

Comparative virulotyping of extended-spectrum cephalosporin-resistant E. coli isolated from broilers, humans on broiler farms and in the general population and UTI patients

During the last decade extended-spectrum cephalosporin (ESC)-resistant Escherichia coli from food-producing animals, especially from broilers, have become a major public health concern because of the potential transmission of these resistant bacteria or their plasmid-encoded resistance genes to humans. The objective of this study was to compare ESC-resistant E. coli isolates from broilers (n=149), humans in contact with these broilers (n=44), humans in the general population (n=63), and patients with a urinary tract infection (UTI) (n=10) with respect to virulence determinants, phylogenetic groups and extended-spectrum β-lactamase (ESBL)/plasmidic-AmpC (pAmpC) genes. The most prevalent ESBL/pAmpC genes among isolates from broilers and individuals on broiler farms were bla_CTX-M-1, bla_CMY-2 and bla_SHV-12. In isolates from humans in the general population bla_CTX-M-1, bla_CTX-M-14 and bla_CTX-M-15 were found most frequently, whereas in UTI isolates bla_CTX-M-15 predominated. The marker for enteroaggregative E. coli, aggR, was only identified in a broiler and human isolates from the general population. The extraintestinal virulence genes afa and hlyD were exclusively present in human isolates in the general population and UTI isolates. Multivariate analysis, based on ESBL/pAmpC resistance genes, virulence profiles and phylogenetic groups, revealed that most UTI isolates formed a clearly distinct group. Isolates from broilers and humans associated with broiler farms clustered together. In contrast, isolates from the general population showed some overlap with the former two groups but primarily formed a separate group. These results indicate than transmission occurs between broilers and humans on broiler farms, but also indicate that the role of broilers as a source of foodborne transmission of ESC-resistant E. coli to the general population and subsequently causative agents of human urinary tract infections is likely relatively small.

Escherichia coli β-Lactamases: What Really Matters

Escherichia coli strains belonging to diverse pathotypes have increasingly been recognized as a major public health concern. The β-lactam antibiotics have been used successfully to treat infections caused by pathogenic E. coli. However, currently, the utility of β-lactams is being challenged severely by a large number of hydrolytic enzymes – the β-lactamases expressed by bacteria. The menace is further compounded by the highly flexible genome of E. coli, and propensity of resistance dissemination through horizontal gene transfer and clonal spread. Successful management of infections caused by such resistant strains requires an understanding of the diversity of β-lactamases, their unambiguous detection, and molecular mechanisms underlying their expression and spread with regard to the most relevant information about individual bacterial species. Thus, this review comprises first such effort in this direction for E. coli, a bacterial species known to be associated with production of diverse classes of β-lactamases. The review also highlights the role of commensal E. coli as a potential but under-estimated reservoir of β-lactamases-encoding genes.