Bacteriophages from Arsenic-Resistant Bacteria Transduced Resistance Genes, which Changed Arsenic Speciation and Increased Soil Toxicity

ABSTRACT Resistance to carbapenem antibiotics through the production of New Delhi metallo-β-lactamase-1 (NDM-1) constitutes an emerging challenge in the treatment of bacterial infections. To monitor the possible source of the spread of these organisms in Dhaka, Bangladesh, we conducted a comparative analysis of wastewater samples from hospital-adjacent areas (HAR) and from community areas (COM), as well as public tap water samples, for the occurrence and characteristics of NDM-1-producing bacteria. Of 72 HAR samples tested, 51 (71%) samples were positive for NDM-1-producing bacteria, as evidenced by phenotypic tests and the presence of the bla NDM-1 gene, compared to 5 of 41 (12.1%) samples from COM samples (P < 0.001). All tap water samples were negative for NDM-1-producing bacteria. Klebsiella pneumoniae (44%) was the predominant bacterial species among bla NDM-1-positive isolates, followed by Escherichia coli (29%), Acinetobacter spp. (15%), and Enterobacter spp. (9%). These bacteria were also positive for one or more other antibiotic resistance genes, including bla CTX-M-1 (80%), bla CTX-M-15 (63%), bla TEM (76%), bla SHV (33%), bla CMY-2 (16%), bla OXA-48-like (2%), bla OXA-1 (53%), and bla OXA-47-like (60%) genes. Around 40% of the isolates contained a qnr gene, while 50% had 16S rRNA methylase genes. The majority of isolates hosted multiple plasmids, and plasmids of 30 to 50 MDa carrying bla NDM-1 were self-transmissible. Our results highlight a number of issues related to the characteristics and source of spread of multidrug-resistant bacteria as a potential public health threat. In view of the existing practice of discharging untreated liquid waste into the environment, hospitals in Dhaka city contribute to the potential dissemination of NDM-1-producing bacteria into the community. IMPORTANCE Infections caused by carbapenemase-producing Enterobacteriaceae are extremely difficult to manage due to their marked resistance to a wide range of antibiotics. NDM-1 is the most recently described carbapenemase, and the bla NDM-1 gene, which encodes NDM-1, is located on self-transmissible plasmids that also carry a considerable number of other antibiotic resistance genes. The present study shows a high prevalence of NDM-1-producing organisms in the wastewater samples from hospital-adjacent areas as a potential source for the spread of these organisms to community areas in Dhaka, Bangladesh. The study also examines the characteristics of the isolates and their potential to horizontally transmit the resistance determinants. The significance of our research is in identifying the mode of spread of multiple-antibiotic-resistant organisms, which will allow the development of containment measures, leading to broader impacts in reducing their spread to the community.

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Metabolism of methylated arsenic compounds by arsenic-resistant bacteria (Klebsiella oxytoca andXanthomonas sp.)

Applied Organometallic Chemistry ◽

10.1002/aoc.590060417 ◽

1992 ◽

Vol 6 (4) ◽

pp. 415-420 ◽

Cited By ~ 16

Author(s):

Shigeru Maeda ◽

Akira Ohki ◽

Kuniaki Miyahara ◽

Kensuke Naka ◽

Shiro Higashi

Keyword(s):

Klebsiella Oxytoca ◽

Resistant Bacteria ◽

Arsenic Compounds ◽

Arsenic Resistant Bacteria

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Prevalence of tetracycline resistance genes among multi-drug resistant bacteria from selected water distribution systems in southwestern Nigeria

Annals of Clinical Microbiology and Antimicrobials ◽

10.1186/s12941-015-0093-1 ◽

2015 ◽

Vol 14 (1) ◽

Cited By ~ 17

Author(s):

Ayodele. T. Adesoji ◽

Adeniyi. A. Ogunjobi ◽

Isaac. O. Olatoye ◽

Douglas. R. Douglas

Keyword(s):

Resistance Genes ◽

Distribution Systems ◽

Water Distribution ◽

Water Distribution Systems ◽

Tetracycline Resistance ◽

Resistant Bacteria ◽

Drug Resistant ◽

Southwestern Nigeria ◽

Tetracycline Resistance Genes ◽

Drug Resistant Bacteria

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Prevalence And Characterization Of Plasmid-Mediated Quinolone Resistance In Various Aquatic Sources

10.32920/ryerson.14652291.v1 ◽

2021 ◽

Author(s):

Farhan Yusuf ◽

Kimberley Gilbride

Keyword(s):

Antibiotic Resistance ◽

Resistance Genes ◽

Antibiotic Resistance Genes ◽

Quinolone Resistance ◽

Resistant Bacteria ◽

Rrna Gene ◽

Environmental Isolates ◽

Topoisomerase Iv ◽

Phenotypic Resistance ◽

Ciprofloxacin Resistance

Bacterial isolates found in aquatic ecosystems often carry antibiotic resistance genes (ARGs). These ARGs are often found on plasmids and transposons, which allows them to be proliferate throughout bacterial communities via horizontal gene transfer (HGT) causing dissemination of multidrug resistance. The increase in antibiotic resistance has raised concerns about the ability to continue to use these drugs to fight infectious diseases. Novel synthetic antibiotics like ciprofloxacin that are not naturally found in the environment were developed to prevent resistances. However, ciprofloxacin resistance has occurred through chromosomal gene mutations of type 2 topoisomerases or by the acquisition of plasmid-mediated quinolone resistances (PMQR). A particular PMQR, qnr genes, encoding for pentapeptide repeat proteins that confer low levels of quinolone resistance and protect DNA gyrase and topoisomerase IV from antibacterial activity. These qnr genes have been identified globally in both clinical and environmental isolates. The aim of this study was to determine the prevalence of ciprofloxacin-resistant bacteria in aquatic environments in the Greater Toronto Area and the potential dissemination of ciprofloxacin resistance. With the selective pressure of ciprofloxacin, we hypothesize that ciprofloxacin-resistant bacteria (CipR) in the environment may carry PMQR mechanisms while the sensitive population (CipS) would not carry PMQR genes. Isolates were tested for resistance to an additional 12 different antibiotics and identified using Sanger sequencing PCR products of the 16S rRNA gene. To determine which genes are responsible for ciprofloxacin resistance, multiplex PCR of associated qnr genes, qnrA, qnrB, and qnrS, was carried out on 202 environmental isolates. Our data demonstrate a similar prevalence of qnr genes was found in CipR (19%) and CipS (14%) populations suggesting that the presence of these genes was not necessarily correlated with the phenotypic resistance to the antibiotic. Furthermore, ciprofloxacinresistant bacteria were found in all locations at similar frequencies suggesting that resistance genes are widespread and could possibly arise through HGT events. Overall, determining the underlying cause and prevalence of ciprofloxacin resistance could help re-establish the effectiveness of these antimicrobial compounds.

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Transcriptional expression of secondary resistance genes ccdB and repA2 is enhanced in presence of cephalosporin and carabapenem in Escherichia coli

10.21203/rs.3.rs-66221/v2 ◽

2020 ◽

Author(s):

Somorita Baishya ◽

Chandrayee Deshamukhya ◽

Jayalaxmi Wangkheimayum ◽

Bhaskar Jyoti Das ◽

Anand Anbarasu ◽

...

Keyword(s):

Resistance Genes ◽

In Silico ◽

Antibiotic Susceptibility ◽

Regulatory Protein ◽

Carbapenem Resistance ◽

Diffusion Method ◽

Resistant Bacteria ◽

Transcriptional Expression ◽

Primary Resistance ◽

Secondary Resistance

Abstract Background: The issue of carbapenem resistance in E.coli is very concerning and it is speculated that cumulative effect of both primary resistance genes and secondary resistance genes that act as helper to the primary resistance genes are the reason behind their aggravation. Therefore, here we attempted to find the role of two secondary resistance genes (SRG) ccdB and repA2 in carbapenem resistance in E. coli (CRE).Methods: Influential genes belonging to secondary resistome that act as helper to the primary resistance genes like blaNDM and blaCTX-M in aggravating β-lactam resistance were selected from an earlier reported in silico study. Transcriptional expression of the selected genes in clinical isolates of E.coli that were discretely harboring blaNDM-1, blaNDM-4, blaNDM-5, blaNDM-7 and blaCTX-M-15 with and without carbapenem and cephalosporin stress (2µg/ml) was determined by real time PCR. Cured mutants sets that were lacking (i) primary resistance genes, (ii) secondary resistance genes and (iii) both primary and secondary resistance genes were prepared by SDS treatment. These sets were then subjected to antibiotic susceptibility testing by Kirby Bauer disc diffusion method.Results: Out of the 21 genes reported in the in silico study, 2 genes viz. repA2 and ccdB were selected for transcriptional expression analysis. repA2, coding replication regulatory protein, was downregulated in response to carbapenems and cephalosporins. ccdB, coding for plasmid maintenance protein, was also downregulated in response to carbapenems except imipenem and cephalosporins. Following plasmid elimination assay increase in diameter of zone of inhibition under stress of both antibiotics was observed as compared to uncured control hinting at the reversion of antibiotic susceptibility by the-then resistant bacteria. Conclusion: SRGs repA2 and ccdB help sustenance of blaNDM and blaCTX-M under carbapenem and cephalosporin stress.

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