Antimicrobial resistance patterns in Enterobacteriaceae isolated from an urban wastewater treatment plant

Silva, Miguel Ferreira da; Vaz‐Moreira, Ivone; González-Pajuelo, María; Nunes, Olga C.; Manaia, Célia M.

doi:10.1111/j.1574-6941.2006.00268.x

Cited by 226 publications

(159 citation statements)

References 35 publications

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“…The percentage of our multiresistant E. coli harbouring integrons was lower than that reported for clinical isolates, but exceeded that recently published by Ferreira da Silva et al (2007), who detected integronspecific regions, with sizes in the range 1 -1.5 kbp or more, in 10% and 9.6% of E. coli spp. isolates from crude and treated wastewater, respectively.…”

Section: Resultscontrasting

confidence: 43%

“…Experimental studies have shown that enteric pathogens can become antibiotic resistant by acquiring conjugative R plasmids from E. coli in the intestine (Poppe et al 2005). However, there are relatively few available data on the prevalence of conjugative R plasmids and integrons in E. coli in wastewater used for irrigation (Ferreira da Silva et al 2007). …”

Section: Introductionmentioning

confidence: 99%

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Plasmid-mediated multiple antibiotic resistance of Escherichia coli in crude and treated wastewater used in agriculture

Pignato

Coniglio

Faro

et al. 2009

Journal of Water and Health

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A total of 273 Escherichia coli isolates from raw and treated municipal wastewaters were investigated to evaluate the frequency and persistence of antibiotic resistance and to detect the occurrence of conjugative R plasmids and integrons. The highest resistance rates were against ampicillin (22.71%), tetracycline (19.41%), sulfamethoxazole (16.84%) and streptomycin (14.28%).Multiple antibiotic resistance was present in 24.17% of the isolates. Several multiple antibioticresistant isolates proved to be able to transfer en bloc their resistance patterns by conjugative R plasmids with different molecular sizes and restriction profiles. Class 1 integrons of 1 or 1.5 kbp were found in 5 out of 24 representative multiresistant E. coli isolates. Although wastewater treatments proved to be effective in eliminating Salmonella spp. and in reaching WHO microbiological standards for safe use of wastewater in agriculture, they were ineffective in reducing significantly the frequency of plasmid-mediated multiple antibiotic resistance in surviving E. coli. Since multiple antibiotic-resistant bacteria carrying integrons and conjugative R plasmids can constitute a reservoir of antibiotic-resistance genes in wastewater reclaimed for irrigation, risks for public health should be considered. Bacterial strains carrying R plasmids and integrons could contaminate crops irrigated with reclaimed wastewater and transfer their resistances to the consumers' intestinal bacteria.

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Section: Resultscontrasting

confidence: 43%

Section: Introductionmentioning

confidence: 99%

Plasmid-mediated multiple antibiotic resistance of Escherichia coli in crude and treated wastewater used in agriculture

Pignato

Coniglio

Faro

et al. 2009

Journal of Water and Health

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“…Although more than 90% of integrons were eliminated, the normalized copy number of class 1 and class 2 integrons was not reduced, and around 10 16 integrons were released each day into environmental water ( Figure 5). It has previously been shown that activated sludge processes, which reduce total bacterial loads, do not specifically eliminate bacteria harboring integrons (Ferreira da Silva et al, 2007;Zhang et al, 2009a). Nevertheless, we found that the WWTP reduced the diversity of gene cassette arrays contained in the raw wastewater, underlining the effect of the biological treatment on the anthropogenic integron pool arriving at the WWTP.…”

Section: Hospital Effluent Impact On Integron Dissemination T Staldercontrasting

confidence: 32%

Quantitative and qualitative impact of hospital effluent on dissemination of the integron pool

et al. 2013

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There is increasing evidence that human activity, and especially the resulting effluent, has a major role in the dissemination of bacterial antibiotic-resistance determinants in the environment. Hospitals are the major antibiotic consumers and thus facilitate the spread of antibiotic resistance. Questions are increasingly being raised about the management of hospital effluents, but their involvement in antibiotic-resistance dissemination has never been assessed. Integrons are a paradigm of genetic transfer between the environmental resistome and both commensal and pathogenic bacteria. In order to assess the impact of hospital activities on antibiotic-resistance dissemination in the environment, we monitored integrons and their gene cassettes in hospital effluents, and their release in the environment. We found that bacterial communities present in a hospital effluent contained a high proportion of integrons. In terms of both their gene cassette diversity and gene cassette arrays, the urban effluent and municipal wastewater treatment plant (WWTP) influent were most similar, whereas the hospital effluent and recirculation sludge exhibited very specific patterns. We found that anthropogenic activities led to the release of abundant integrons and antibiotic-resistance gene cassettes, but we observed no specific impact of hospital activities on the receiving environment. Furthermore, although the WWTP did not reduce the normalized integron copy number, it reduced the diversity of gene cassette arrays contained in the raw wastewater, underlining the effect of the biological treatment on the anthropogenic integron pool arriving at the WWTP.

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“…isolates was also observed in the treated effluent in comparison with the raw wastewater. 33,34 Rizzo et al also found that E. coli population of mutation could survive the disinfection process. 26 Multiple antibiotic resistant bacteria can disseminate antibiotic resistance determinants to susceptible strains of the same species or to other species or genera by different mechanisms, mainly by plasmids.…”

Section: Discussionmentioning

confidence: 99%

Antibiotic resistance, plasmid-mediated quinolone resistance (PMQR) genes and ampC gene in two typical municipal wastewater treatment plants

Ying

et al. 2014

Environ. Sci.: Processes Impacts

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Antibiotic resistant bacteria and plasmid-mediated quinolone resistance genes and ampC gene were investigated for Escherichia coli isolates from two typical municipal wastewater treatment plants in both dry and wet seasons by using the antibiotic susceptibility test and PCR assay, respectively. The results showed that 98.4% of the isolates (1056) were found resistant to antibiotic(s) tested and 90.6% showed multiple resistances to at least three antibiotics. Tetracycline was found to have the highest resistance frequency (70.8%), followed by ampicillin (65.1%), whereas ceftazidime had the lowest resistance frequency of 9.0%.Moreover, 39.2% of the E. coli isolates were carrying plasmids. intI1 had the highest detection rate in the plasmids (38.1%), followed by qnrS, ampC, qnrB, intI2 and aac(6 0 )-Ib-cr. The disinfection process (UV and chlorination) could significantly reduce the number of bacteria, but percentage of the resistant bacteria, resistance frequency for each antibiotic, MAR index and detection rate of the plasmid-mediated resistance genes were all found increasing in the effluents of biological units. The results of this study showed that a more frequent horizontal gene transfer occurred in the biological units. Wastewater treatment plants were an important medium for the recombination and dissemination of antibiotic resistance genes in the environment. Environmental impactThe wide application of antibiotics can lead to environmental contamination with antibiotic residues and development of bacterial resistance to antibiotics. This has become a global public concern. A variety of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were widely detected in various environmental media. Effluents from wastewater treatment plants (WWTPs) are suspected to be one of the main anthropogenic sources for ARGs and ARB. Therefore, it is important to understand the removal and dissemination of ARGs and ARB in WWTPs. Plasmids are the major vectors of horizontal gene transfer (HGT). Quinolone resistance genes and ampC gene are two kinds of ARGs contained in the plasmids normally found in many Enterobactericeae isolated from clinical samples. Unfortunately, little is known about their occurrence and characteristics in WWTPs. This study aimed to investigate the antibiotic resistance proles in Escherichia coli isolated from two typical municipal wastewater treatment plants (activated sludge and oxidation ditch processes), to characterize plasmid-mediated quinolone resistance genes, ampC gene and integrons by the polymerase chain reaction (PCR), and to assess the effects of treatment processes on the removal of ARB and ARGs in the WWTPs. The results showed that the treatment processes especially disinfection processes (UV and chlorination) could signicantly reduce the number of bacteria, but increase bacterial resistance in the biological treatment units. The ndings reect the importance of WWTPs as a reservoir of ARB and ARGs, and as a medium for their recombination and dissemination in the en...

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Antimicrobial resistance patterns in Enterobacteriaceae isolated from an urban wastewater treatment plant

Cited by 226 publications

References 35 publications

Plasmid-mediated multiple antibiotic resistance of Escherichia coli in crude and treated wastewater used in agriculture

Plasmid-mediated multiple antibiotic resistance of Escherichia coli in crude and treated wastewater used in agriculture

Quantitative and qualitative impact of hospital effluent on dissemination of the integron pool

Antibiotic resistance, plasmid-mediated quinolone resistance (PMQR) genes and ampC gene in two typical municipal wastewater treatment plants

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