scholarly journals Fate and seasonal change of Escherichia coli resistant to different antibiotic classes at each stage of conventional activated sludge process

2020 ◽  
Vol 18 (6) ◽  
pp. 879-889 ◽  
Author(s):  
Ryo Honda ◽  
Chihiro Tachi ◽  
Mana Noguchi ◽  
Ryoko Yamamoto-Ikemoto ◽  
Toru Watanabe

Abstract This study investigated the impact of each treatment stage of the activated sludge process on the fate of antibiotic resistant bacteria (ARB) in wastewater treatment plants (WWTPs). Wastewater and sludge samples were collected monthly at each stage of a commercial-scale WWTP. After 20–25 strains of indicator Escherichia coli were isolated from each sample on Chromocult Coliform Agar, antibiotic resistance of the isolates to amoxicillin (AMX), ciprofloxacin (CIP), norfloxacin (NFX), kanamycin (KM), sulfamethoxazole/trimethoprim (ST) and tetracycline (TC) were tested with the Kirby–Bauer disk diffusion method. As a result, activated sludge in the aeration tank and return sludge had higher abundance of antibiotic resistant E. coli than influent wastewater and secondary treatment effluent. AMX resistant E. coli was enriched in return sludge at the secondary clarifier. Higher temperature was also likely to cause an increase of AMX resistant E. coli in sludge. The antibiotic resistance profile of E. coli in secondary treatment effluent was more dependent on activated sludge than influent wastewater. These results suggested that activated sludge in WWTP possibly serves as a reservoir of ARB, and that behavior of ARB in WWTP differs by antibiotic classes.

Author(s):  
Reza Ranjbar ◽  
Maryam Zeynali ◽  
Nooshin Sohrabi ◽  
Asghar Ali Kamboh

BACKGROUND <br />Hospital wastewaters may contain antibiotic resistant bacteria such as Escherichia coli. These E. coli harbor integron genes that are responsible for antibiotic resistance. The purpose of the current study was to evaluate the frequency of class 1 and 2 integrons in environmental antibiotic resistant E. coli strains isolated from the hospital wastewaters in Tehran, Iran.<br /><br />METHODS<br />As a descriptive cross-sectional study, this research was performed from April to September 2015 on hospital wastewaters in Tehran. Bacterial isolation and identification was performed by standard biochemical and bacteriological procedures. Susceptibility testing was done by employing the disk diffusion method using different antibiotics. Total DNAs were extracted to evaluate the presence of class 1 and 2 integrons by using the polymerase chain reaction (PCR) method with specific primers. <br /><br />RESULTS<br />Fifty E. coli strains were isolated and identified from the wastewaters of 25 hospitals in Tehran. The phenotype results showed that 46 isolates (92%) were resistant to at least one antibiotic and 27 isolates (54%) were multidrug resistant. PCR showed that 35 (70%) and 20 (40%) of the isolates had class 1 and 2 integrons respectively and 14 isolates (28%) had both class 1 and class 2 integrons.<br /><br />CONCLUSION<br />This study has shown a considerable presence of class 1 and class 2 integrons in E. coli strains isolated from hospital wastewaters in Tehran. Proper antibiotics prescription and appropriate hospital wastewater treatment can prevent resistance genes in E. coli from circulating in the environment.


Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3449
Author(s):  
Cristina-Mirabela Gaşpar ◽  
Ludovic Toma Cziszter ◽  
Cristian Florin Lăzărescu ◽  
Ioan Ţibru ◽  
Marius Pentea ◽  
...  

This study aimed to compare the antibiotic resistance levels of the indicator bacteria Escherichia coli in wastewater samples collected from two hospitals and two urban communities. Antimicrobial susceptibility testing was performed on 81 E. coli isolates (47 from hospitals and 34 from communities) using the disc diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) methodology. Ten antibiotics from nine different classes were chosen. The strains isolated from the community wastewater, compared to those from the hospital wastewater, were not resistant to gentamicin (p = 0.03), but they showed a significantly higher susceptibility—increased exposure to ceftazidime (p = 0.001). Multidrug resistance was observed in 85.11% of the hospital wastewater isolates and 73.53% of the community isolates (p > 0.05). The frequency of the presumed carbapenemase-producing E. coli was higher among the community isolates (76.47% compared to 68.09%) (p > 0.05), whereas the frequency of the presumed extended-spectrum beta-lactamase (ESBL)-producing E. coli was higher among the hospital isolates (21.28% compared to 5.88%) (p > 0.05). The antibiotic resistance rates were high in both the hospital and community wastewaters, with very few significant differences between them, so the community outlet might be a source of resistant bacteria that is at least as important as the well-recognised hospitals.


Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 618
Author(s):  
Michaela Sannettha van den Honert ◽  
Pieter Andries Gouws ◽  
Louwrens Christiaan Hoffman

Although limited, studies have found conflicting results on whether co-grazing results in significant antibiotic resistance transfer between species. This type of farming system can act as a vector in the geographical spread of antibiotic-resistant bacteria in the environment. The aim of this study was to determine the antibiotic-resistant patterns between co-grazing and non-co-grazing livestock and wildlife species in South Africa. Escherichia coli was isolated from the faeces of various wildlife and livestock species from two farms in South Africa and was tested for antibiotic resistance using the Kirby–Bauer disk diffusion method against chloramphenicol, nalidixic acid, ampicillin, streptomycin, sulphafurazole, and tetracycline. A selection of some common antibiotic-resistant genes (blaCMY, aadA1, sul1, sul2, tetA, and tetB) were detected using PCR. The E. coli isolates from wildlife and livestock that co-grazed showed no significant differences in antibiotic resistance patterns. However, this was not the case for tetracycline resistance as the livestock isolates were significantly more resistant than the co-grazing wildlife isolates. The E. coli isolates from the non-co-grazing livestock and wildlife had significant differences in their antibiotic susceptibility patterns; the wildlife E. coli isolates were significantly more resistant to sulphafurazole and streptomycin than the livestock isolates, whilst those isolated from the cattle were significantly more resistant to ampicillin than the wildlife and sheep isolates. The results of this study suggest that there could be an exchange of antibiotic-resistant bacteria and genes between livestock and wildlife that co-graze.


2020 ◽  
Vol 13 (6) ◽  
pp. 1037-1044
Author(s):  
Mona A. A. AbdelRahman ◽  
Heba Roshdy ◽  
Abdelhafez H. Samir ◽  
Engy A. Hamed

Aim: Antimicrobial resistance is a global health threat. This study investigated the prevalence of Escherichia coli in imported 1-day-old chicks, ducklings, and turkey poults. Materials and Methods: The liver, heart, lungs, and yolk sacs of 148 imported batches of 1-day-old flocks (chicks, 45; ducklings, 63; and turkey poults, 40) were bacteriologically examined for the presence of E. coli. Results: We isolated 38 E. coli strains from 13.5%, 6.7%, and 5.4% of imported batches of 1-day-old chicks, ducklings, and turkey poults, respectively. They were serotyped as O91, O125, O145, O78, O44, O36, O169, O124, O15, O26, and untyped in the imported chicks; O91, O119, O145, O15, O169, and untyped in the imported ducklings; and O78, O28, O29, O168, O125, O158, and O115 in the imported turkey poults. The E. coli isolates were investigated for antibiotic resistance against 16 antibiotics using the disk diffusion method and were found resistant to cefotaxime (60.5%), nalidixic acid (44.7%), tetracycline (44.7%), and trimethoprim-sulfamethoxazole (42.1%). The distribution of extended-spectrum β-lactamase (ESBL) and ampC β-lactamase genes was blaTEM (52.6%), blaSHV (28.9%), blaCTX-M (39.5%), blaOXA-1 (13.1%), and ampC (28.9%). Conclusion: Imported 1-day-old poultry flocks may be a potential source for the dissemination of antibiotic-resistant E. coli and the ESBL genes in poultry production.


1987 ◽  
Vol 14 (2) ◽  
pp. 234-238 ◽  
Author(s):  
G. R. Finch ◽  
D. W. Smith

A paired experiment using seven batches of activated sludge final effluent was used to determine the effect of ozone on the multiple-antibiotic-resistant (MAR) population of Escherichia coli. The experiments were conducted using a batch stirred tank reactor. No statistically significant difference was found in the proportions of MAR E. coli in the ozonated secondary effluent when compared with the nonozonated effluent. This was true for all levels of multiple resistance including simultaneous resistance to greater than or equal to five antibiotics. This suggests that using ozone for water and wastewater disinfection will not select for antibiotic-resistant bacteria as has been reported by other investigators for chlorine and ultraviolet radiation. Key words: antibiotic resistance, Escherichia coli, wastewater, ozone, disinfection, activated sludge effluent.


2021 ◽  
Vol 15 (5) ◽  
pp. 1080-1083
Author(s):  
Nazia Mir ◽  
Sidrah Saleem ◽  
Muhammad Imran ◽  
Ayesha Ghazal ◽  
Muhammad Usman

Background: The major faecal coliform is Escherichia coli which contaminates the drinking water from human and animal faecal waste. In developing regions drinking water is a vital source of microbiological pathogens. Multi-drug resistant (MDR) is defined as resistance to one or more antibiotic groups. An E. coli count greater than 4/dl in municipal drinking water is indicative of unacceptable fecal contamination. Aim: To find out the frequency of MDR E. coli in water system of Lahore, Pakistan. Methodology: Drinking water was collected from different towns of Lahore. The samples were processed using Membrane Filtration Technique. In the present study, Multidrug Resistant E.coli was isolated and antibiotic resistant pattern was seen against 16 most commonly antimicrobials, using Kirby Bauer disc diffusion method. Results: Total 100 water samples were collected, frequency of Escherichia coliisolated was 27% and frequency of MDR E.coli was 19%. The highest resistance showed by the organism towards Ampicillin (AMP) 21(81.48%), Augmentin (AMC), and Ceftazidime (CAZ) 14(51.85%) respectively. In this study also frequency of Extended Spectrum β-Lactamases were seen. Most common organisms isolated were E. coli 7% and Klebsiella 5%. Frequency of other coliforms isolated from drinking water other than E. coli was Klebsiella species 26%, Pseudomonas species 27%, Enterobacter 7%, Citrobacter species 8% and Acinetobacter species 5%. Conclusion: This study revealed that drinking water of Lahore city is heavilycontaminated with pathogenic microorganisms. A high proportion of antibiotic resistant is due to overuse of antibiotics, in patients with mild infections and secretion of these resistant bacteria from patients to environment. One of the reasons could be the mixing of sewage lines with drinking water supply. So, there is solely requirement for further studies for the identification of the sources for these contaminants. Keywords: Isolates, E. coli, Klebsiella, Multi-drug resistant (MDR)


Author(s):  
Daile Meek Salvador-Membreve ◽  
Windell L. Rivera

Abstract Lakes are one of the sinks of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs); however, information on ARB and ARGs in lakes in the Philippines is scarce. In this study, Escherichia coli was isolated from the largest freshwater lake in the Philippines, Laguna Lake, to detect antibiotic resistance and the presence of ARGs. Broth microdilution assay (BMA) and molecular identification of five environmentally prevalent ARGs (strA, blaCTX-M, blaSHV, blaTEM, and tetA) were performed. The majority (75.70%) of the isolates harbored at least one of the targeted antibiotic genes. Multiplex PCR detected about 49.07% of the isolates had genes for extended-spectrum β-lactamases (ESBL), which were mostly represented by blaTEM (47.66%). The genes strA and tetA were observed in this study with detection frequencies of 29.91 and 45.33%, respectively. About 95.69% of thermotolerant E. coli isolates were non-susceptible to six different antibiotics using BMA. Nearly 37% of the isolates were found to be multidrug-resistant (MDR) with most isolates resistant to ampicillin (81.72%). Furthermore, the occurrence of ESBL genes was significantly correlated with tetA genes (P = 0.013). To date, this study is the first to report on the presence of MDR and thermotolerant E. coli in Laguna Lake, Philippines.


Author(s):  
Mojtaba Bonyadian ◽  
Sara Barati ◽  
Mohammad Reza Mahzounieh

Background and Objectives: Escherichia coli is a common enteric pathogen of human and livevestock. Antibiotic resis- tance is the main concern of public health. The aim of this study was to detect this bacterium in stool samples of diarrheal patients and identify the phenotypic and genotypic characterizations of antibiotic-resistant isolates such as dfrA1, sul1, citm, tetA, qnr, aac(3)-IV in Shahrekord. Materials and Methods: Two hundred fifty diarrheal stool samples from patients were collected. Microbiological and biochemical examinations were done to detect E. coli. Phenotypic and genotypic antibiotic resistance of the isolates were determined using dick diffusion method and polymerase chain reaction (PCR), respectively. Results: Among 114 E. coli isolates, the least resistance was for gentamicin (0%) and the most resistance was for trimetho- prim (79.8%). The resistance to sulfamethoxazole, ciprofloxacin, ampicillin, and tetracycline were 71.05%, 10.5%, 52.63%, and 3.5% respectively. The results of PCR assay revealed that 10 isolates contain sul1, 49 isolates harbor citm, 8 isolates tetA, 36 isolates dfrA1, 11 isolates qnr genes but there was no isolate with aac(3)-IV gene. In comparison between phenotypic and genotypic of the isolates revealed that citm, tetA, dfrA1, qnr, sul1, aac(3)-IV genes covered 42.98%, 7.01%, 31.57%, 9.64%, 8.7%, 0% of the antibiotic resistance, respectively. Conclusion: Our results revealed that all isolates harbor one or more antibiotic resistance genes and that the PCR is a fast practical and appropriate method to determine the presence of antibiotic resistance genes.


2009 ◽  
Vol 7 (2) ◽  
pp. 251-258 ◽  
Author(s):  
S. Pignato ◽  
M. A. Coniglio ◽  
G. Faro ◽  
F. X. Weill ◽  
G. Giammanco

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 antibiotic-resistant 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.


2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Erik Paulshus ◽  
Kaisa Thorell ◽  
Jessica Guzman-Otazo ◽  
Enrique Joffre ◽  
Patricia Colque ◽  
...  

ABSTRACT Antibiotic resistance in bacteria is an emerging problem globally. Resistant bacteria are found in human and animal microbiota, as well as in the environment. Wastewater receives bacteria from all these sources and thus can provide a measurement of abundance and diversity of antibiotic-resistant bacteria circulating in communities. In this study, water samples were collected from a wastewater pump station in a Norwegian suburban community over a period of 15 months. A total of 45 daily samples were cultured and analyzed for the presence of Escherichia coli. Eighty E. coli-like colonies were collected from each daily sample and then phenotyped and analyzed for antibiotic resistance using the PhenePlate-AREB system. During the sampling period, two unique E. coli phenotypes with resistance to cefotaxime and cefpodoxime indicating carriage of extended-spectrum β-lactamases (ESBL) were observed repeatedly. Whole-genome sequencing of 15 representative isolates from the two phenotypes identified these as two distinct clones belonging to the two globally spread E. coli multilocus sequence types (STs) ST131 and ST648 and carrying blaCTX-M-15. The number of ESBL-positive E. coli strains in the community wastewater pump station was 314 of 3,123 (10%) analyzed E. coli strains. Of the ESBL-positive isolates, 37% belonged to ST648, and 7% belonged to ST131. Repeated findings of CTX-M-15-positive ST648 and ST131 over time indicate that these STs are resident in the analyzed wastewater systems and/or circulate abundantly in the community.


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