Multiresistant Enterobacteriaceae with class 1 and class 2 integrons in a municipal wastewater treatment plant

Mokracka, Joanna; Koczura, Ryszard; Kaznowski, Adam

doi:10.1016/j.watres.2012.03.037

Cited by 100 publications

(71 citation statements)

References 49 publications

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“…Our observation was in agreement with previous studies which reported that the collective 577 proportion of Escherichia coli resistant to antibiotics, for example cephalothin, amoxicillin and 578 beta-lactams increased significantly in the effluent as compared to the influent (da Silva et al 579 M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 25 2007, Galvin et al 2010, Mokracka et al 2012. These studies collectively suggest that ARB 580 including Enterobacteriaceae may be selectively enriched upon chlorination of effluent.…”

Section: A C C E P T E D Accepted Manuscriptsupporting

confidence: 89%

Removal of bacterial contaminants and antibiotic resistance genes by conventional wastewater treatment processes in Saudi Arabia: Is the treated wastewater safe to reuse for agricultural irrigation?

et al. 2015

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Please cite this article as: Al-Jassim, N., Ansari, M.I., Harb, M., Hong, P.-Y., Removal of bacterial contaminants and antibiotic resistance genes by conventional wastewater treatment processes in Saudi Arabia: Is the treated wastewater safe to reuse for agricultural irrigation?, Water Research (2015Research ( ), doi: 10.1016Research ( /j.watres.2015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT Abstract 1This study aims to assess the removal efficiency of microbial contaminants in a local wastewater 2 treatment plant over the duration of one year, and to assess the microbial risk associated with 3 reusing treated wastewater in agricultural irrigation. The treatment process achieved 3.9 logs 4 removal of heterotrophic bacteria and up to 3.9 logs removal of fecal coliforms. The final 5 chlorinated effluent had 1.8 x 10 2 MPN/100 mL of fecal coliforms and fulfils the required quality 6 for restricted irrigation. 16S rRNA gene-based high-throughput sequencing showed that several 7 genera associated with opportunistic pathogens (e.g. Acinetobacter, Aeromonas, Arcobacter, 8 Legionella, Mycobacterium, Neisseria, Pseudomonas and Streptococcus) were detected at 9 relative abundance ranging from 0.010 to 21 % of the total microbial community in the influent. 10

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Section: A C C E P T E D Accepted Manuscriptsupporting

confidence: 89%

Removal of bacterial contaminants and antibiotic resistance genes by conventional wastewater treatment processes in Saudi Arabia: Is the treated wastewater safe to reuse for agricultural irrigation?

et al. 2015

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“…The widespread use of antimicrobials and their inappropriate disposal have been postulated to be predisposing factors for the increase in antimicrobial resistance (Mokracka et al, 2012;Pauwels and Verstraete, 2006;Zuccato et al, 2010). The contamination of surface water by antimicrobials increases the selection of resistant microorganisms and the transfer of genetic material between species.…”

Section: Introductionmentioning

confidence: 99%

Toxic concentrations of metronidazole to Microcystis protocystis

et al. 2014

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Antimicrobials are among the most commonly used drugs and have become a class of contaminants with great environmental importance. Metronidazole is an antimicrobial used for the therapeutic management of several human diseases. The toxicity of antimicrobials on aquatic species may affect sensitive microorganisms and reduce metabolic processes. Cyanobacteria is a group of organisms that are of great ecological importance in aquatic environments. Studies indicate that cyanobacteria are very sensitive to some antimicrobials. Therefore, it is necessary to evaluate the effects of metronidazole contamination on phytoplankton. The aim of this study was to investigate the effects of metronidazole on the growth of the cyanobacterium Microcystis protocystis and to evaluate the stability of this antimicrobial agent in the culture medium over a period of 96 hours. M. protocystis was resistant to growth inhibition by metronidazole. The EC50 of this antimicrobial for M. protocystis was 117.3 mg L -1 . Under the growth inhibition test conditions, neither a significant change in the MNZ concentration nor the presence of drug metabolites or degradation products was observed. These results indicate low cellular uptake of the antimicrobial agent and its persistence in the culture medium.Keywords: antimicrobials, toxicity, metronidazole, cyanobacterium, Microcystis protocystis. Concentrações tóxicas de metronidazol para Microcystis protocystis ResumoAntimicrobianos estão entre os fármacos mais usados e tem se tornado uma classe emergente de contaminantes com grande importância ambiental. A toxicidade dos antimicrobianos sobre as espécies aquáticas podem afetar microrganismos sensíveis e reduzir seus processos metabólicos. O Metronidazol é um antimicrobiano usado para o manejo terapêutico de várias doenças humanas. Cyanobacteria é um grupo de organismos de grande importância ecológica no ambiente aquático. O estudo visou investigar os efeitos do metronidazol-MNZ sobre o crescimento da cianobactéria Microcystis protocystis e avaliar a persistência do antimicrobiano no meio de cultivo durante 96h. A M. protocystis mostrou-se resistente à inibição de crescimento pelo MNZ. A EC 50% do MNZ para a espécie foi 117,3 mg L -1 . Nas condições do teste de inibição de crescimento não foi observada variação significativa da concentração de MNZ nem a presença de metabólitos ou produtos de degradação do fármaco, indicando baixa captação celular do antimicrobiano e sua persistência no meio de cultivo.Palavras chave: antimicrobiano, toxicidade, metronidazol, cianobactéria, Microcystis protocystis.

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“…Encoding an adenylyltransferase that confers resistance to streptomycin and spectinomycin, aadA2, was prevalent in the inoculated sludge and OTC-exposed sludge. The aadA genes have been reported as the most prevalent cassette gene of intI1 in sewage and OTC production wastewater treatment plants Mokracka et al 2012), possibly resulting in its prevalence throughout the treatment process. The dfrA27 encoding dihydrofolate reductase, which confers resistance to trimethoprim, appeared when the system was exposed to OTC.…”

Section: Discussionmentioning

confidence: 99%

Response of activated sludge to the treatment of oxytetracycline production waste stream

Liu

Zhang

Ding

et al. 2012

Appl Microbiol Biotechnol

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To investigate how the microbial community in activated sludge responded to high antibiotic levels, a benchscale aerobic wastewater treatment system was used to treat oxytetracycline (OTC) mother liquor (OTC-ML). Removal efficiency of chemical oxygen demand decreased from 64.9 to 51.0 % when the OTC level increased from 191.6 to 620.5 mg/L, respectively. According to the cloning results, Psychrobacter and Cryptophyta were the dominant bacterium and eukaryote in the inoculated sludge, respectively, both of which related to low temperature. After OTC exposure, Alphaproteobacteria and Betaproteobacteria became the dominant bacteria, with a small proportion of Firmicutes, Actinobacteria appeared, and fungi (mainly Saccharomycotina) became the dominant eukaryotes, indicating the possible functions of these microorganisms in the wastewater treatment of OTC-ML. The relative abundance of nine tetracycline resistance genes and four mobile elements (class 1 integron, class 2 integron, transposon Tn916/1545, and pattern 1 insertion sequence common region) significantly increased from undetectable to 2.1×10 −3 in the inoculated sludge to 1.7×10 −4 -9.8×10 −1 in sludge exposed to 620.5 mg/L OTC by using real-time PCR. The variety of gene cassette arrays of class 1 integron in the sludge samples increased with increasing OTC exposure concentration.

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Multiresistant Enterobacteriaceae with class 1 and class 2 integrons in a municipal wastewater treatment plant

Cited by 100 publications

References 49 publications

Removal of bacterial contaminants and antibiotic resistance genes by conventional wastewater treatment processes in Saudi Arabia: Is the treated wastewater safe to reuse for agricultural irrigation?

Removal of bacterial contaminants and antibiotic resistance genes by conventional wastewater treatment processes in Saudi Arabia: Is the treated wastewater safe to reuse for agricultural irrigation?

Toxic concentrations of metronidazole to Microcystis protocystis

Response of activated sludge to the treatment of oxytetracycline production waste stream

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