Comparison of enterococcal populations related to urban and hospital wastewater in various climatic and geographic European regions

Abstract

Aims: Scarce knowledge about the distribution of enterococci species in wastewaters limits any statement on their reliability as faecal indicators or the implications of antibiotic resistance transmission by these organisms through the water cycle. Enterococci have been involved in nosocomial infections and the spreading of antibiotic resistance through the food chain. The species distribution of enterococci and the presence of resistant strains to vancomycin and erythromycin were analysed in more than 400 raw and treated urban wastewaters, surface waters receiving these treated wastewaters and hospital wastewaters from three European countries. Methods and Results: A total of 9296 strains were isolated and biochemically phenotyped. The species identification was based on the comparison of biochemical profiles with those of more than 20 000 enterococci isolates from an international study. The prevalence of enterococcal isolates resistant to erythromycin (ERE) and vancomycin (VRE) was also analysed. ERE strains were present in a high proportion in all the studied samples. VRE strains were also isolated in all studied countries despite the time elapsed since the use of antimicrobial glycopeptides in animal production was banned in the European Union. Conclusions: Enterococcus faecalis and Ent. faecium were the most abundant species in all the studied wastewaters. All the studied wastewaters demonstrated high diversity and similar population structure and composition. ERE and VRE isolates were detected in most of the wastewaters. Significance and Impact of the Study: Urban and hospital wastewaters are useful targets for the evaluation of the prevalence of ERE and VRE isolates in the environment. It appears that these bacteria could pass through wastewater treatment plants and be transferred to surface waters.

Antibiotic Resistant Bacteria from Treated and Untreated Hospital Wastewater at Ayder Referral Hospital, Mekelle, North Ethiopia

“…The same result was reported from Alice, Eastern Cape province of South Africa [28] and European countries [29] [30], where higher rate of resistance in bacterial isolates from final effluent of wastewater treatment plant was found. Presences of high percentage of drug resistant isolates from the final effluent of WWTP suggest that, hospital wastewater could have contributed massively to the resistances observed among the isolates from the final effluent.…”

Distribution and persistence of fecal bacterial populations in liquid and dewatered sludge from a biological treatment plant

“…Clusters were constituted by isolates which presented a correlation coefficient of PhP-profiles higher than 0.975. FC and ENT isolates were identified by comparing their biochemical PhP-profiles obtained in the present study with those which were identified in previous studies (Blanch et al, 2003;Vilanova et al, 2004). Then, species identification of the FC representative isolates was performed using the API 20E gallery following the manufacturer's instructions and database profiling (bioMérieux, La Balme, France).…”

“…In addition, another 3 sets of membranes with filtrated samples were pre-incubated on Brain Heart Infusion Agar (BHIA) (Difco) at 37°C for no more than 2 h for the recovery of stressed enterococci (Anonymous, 1998). Membranes were then transferred onto m-Enterococcus Agar plates (MEA) (Difco), MEA with 8 mg L Ϫ1 of erythromycin (Sigma-Aldrich, Saint Quentin Fallveir, France) and MEA with 8 mg L Ϫ1 of vancomycin (Sigma-Aldrich), for the enumeration of total enterococci and, enterococci resistant to erythromycin and to vancomycin respectively as previously described (Blanch et al, 2003). Plates were incubated at 37°C for 48 h. Then they were transferred to Bile Esculine Agar (BEA) (Difco) for 1 h at 44°C to confirm the enterococci colonies on the basis of the hydrolysis of esculine (Manero and Blanch, 1999 tures of these strains were obtained and confirmed by hydrolysis of esculine on BEA as described above.…”

“…gallinarum and Enterococcus flavescens (C-G-F group) were considered as a unique group (Blanch et al, 2003). Those FC and ENT isolates not identified were grouped in "Others."…”

Role of House Flies in the Ecology of Enterococcus faecalis from Wastewater Treatment Facilities

“…Waste received from environments under significant antibiotic pressure, such as hospitals, consistently contains a greater proportion of singly and multiple drug-resistant bacteria [9,22,26,28,38,60] and AR enterococci are commonly recovered from sewage [2,8,9,28,38,47,51,55]. House flies and other filth flies often have direct and unhindered access to many steps in the waste processing flow and therefore may acquire bacteria associated with the waste.…”