Genetic Context and Structural Diversity of Class 1 Integrons from Human Commensal Bacteria in a Hospital Intensive Care Unit

Betteridge, Thu; Partridge, Sally R.; Iredell, Jonathan R.; Stokes, H. W.

doi:10.1128/aac.01831-10

Cited by 34 publications

(27 citation statements)

References 32 publications

(36 reference statements)

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“…In this study, the average level of intI1 genes detected was at least 2 orders of magnitude lower than that detected in hospital wastewaters in China, with tet and sul genes detected in a lower range as well (37). Class 1 integrons are responsible for the spread and carriage of antibiotic resistance gene cassettes in Gram-negative pathogens (38,39). The high concentrations of class 1 integrons detected in raw wastewater and the occurrence in ARB isolates were consistent with recent literature reports, e.g., 97% for E. coli isolates in Iran (40), 76% for E. coli and 43% for Salmonella isolates in Netherlands (41), 67% for E. coli isolates in Spain (42), and 63% for E. coli isolates in Thailand (43).…”

Section: Discussionmentioning

confidence: 99%

Occurrences and Characterization of Antibiotic-Resistant Bacteria and Genetic Determinants of Hospital Wastewater in a Tropical Country

Chen

et al. 2016

Antimicrob Agents Chemother

101

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e Wastewater discharged from clinical isolation and general wards at two hospitals in Singapore was examined to determine the emerging trends of antibiotic resistance (AR). We quantified the concentrations of 12 antibiotic compounds by analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS), antibiotic-resistant bacteria (ARB), the class 1 integrase gene (intI1), and 16 antibiotic resistance genes (ARGs) that confer resistance to 10 different clinically relevant antibiotics. A subset of 119 antibiotic-resistant isolates were phylogenetically classified and tested for the presence of ARGs encoding resistance to ␤-lactam antibiotics (bla NDM , bla KPC , bla SHV , bla CTX-M ), amikacin [aac(6=)-Ib], co-trimoxazole (sul1, sul2, dfrA), ciprofloxacin (qnrA, qnrB), and the intI1 gene. Among these resistant isolates, 80.7% were detected with intI1 and 66.4% were found to carry at least 1 of the tested ARGs. Among 3 sampled locations, the clinical isolation ward had the highest concentrations of ARB and the highest levels of ARGs linked to resistance to ␤-lactam (bla KPC ), co-trimoxazole (sul1, sul2, dfrA), amikacin [aac(6=)-Ib], ciprofloxacin (qnrA), and intI1. We found strong positive correlations (P < 0.05) between concentrations of bacteria resistant to meropenem, ceftazidime, amikacin, co-trimoxazole, and ciprofloxacin and abundances of bla KPC , aac(6=)-Ib, sul1, sul2, dfrA, qnrA, and intI1 genes.

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Section: Discussionmentioning

confidence: 99%

Occurrences and Characterization of Antibiotic-Resistant Bacteria and Genetic Determinants of Hospital Wastewater in a Tropical Country

Chen

et al. 2016

Antimicrob Agents Chemother

101

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“…They are also present in the commensal bacteria of farm animals, where the integron carriage by commensal E. coli can rise to 80% (179)(180)(181). These commensal bacteria house integrons with diverse structures and act as a conduit for lateral gene transfer of resistance determinants between environmental bacteria, other commensals, and pathogens (182,183).…”

Section: Integrons and Resistance Genes As Pollutantsmentioning

confidence: 99%

Integrons: Past, Present, and Future

Gillings

2014

Microbiol Mol Biol Rev

570

472

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SUMMARY Integrons are versatile gene acquisition systems commonly found in bacterial genomes. They are ancient elements that are a hot spot for genomic complexity, generating phenotypic diversity and shaping adaptive responses. In recent times, they have had a major role in the acquisition, expression, and dissemination of antibiotic resistance genes. Assessing the ongoing threats posed by integrons requires an understanding of their origins and evolutionary history. This review examines the functions and activities of integrons before the antibiotic era. It shows how antibiotic use selected particular integrons from among the environmental pool of these elements, such that integrons carrying resistance genes are now present in the majority of Gram-negative pathogens. Finally, it examines the potential consequences of widespread pollution with the novel integrons that have been assembled via the agency of human antibiotic use and speculates on the potential uses of integrons as platforms for biotechnology.

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“…We were unable to identify the content of the integron cassette arrays in the remaining 16 qacE⌬1 ϩ and sul1 ϩ (intI1-positive) samples. The lack of amplification in these last samples could be the result of the cassette array being too large for PCR amplification or the consequence of the lack of a 3=-conserved sequence region (43,44).…”

Section: Phenotypic Resistance Overviewmentioning

confidence: 99%

Antimicrobial Resistance Determinants in Acinetobacter baumannii Isolates Taken from Military Treatment Facilities

Taitt

Łęski

Stockelman

et al. 2014

Antimicrob Agents Chemother

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c Multidrug-resistant (MDR) Acinetobacter baumannii infections are of particular concern within medical treatment facilities, yet the gene assemblages that give rise to this phenotype remain poorly characterized. In this study, we tested 97 clinical A. baumannii isolates collected from military treatment facilities (MTFs) from 2003 to 2009 by using a molecular epidemiological approach that enabled for the simultaneous screening of 236 antimicrobial resistance genes. Overall, 80% of the isolates were found to be MDR, each strain harbored between one and 17 resistant determinants, and a total of 52 unique resistance determinants or gene families were detected which are known to confer resistance to ␤-lactam (e.g., bla GES-11 , bla TEM , bla OXA-58 ), aminoglycoside (e.g., aphA1, aacC1, armA), macrolide (msrA, msrB), tetracycline [e.g., tet(A), tet(B), tet(39)], phenicol (e.g., cmlA4, catA1, cat4), quaternary amine (qacE, qacE⌬1), streptothricin (sat2), sulfonamide (sul1, sul2), and diaminopyrimidine (dfrA1, dfrA7, dfrA19) antimicrobial compounds. Importantly, 91% of the isolates harbored bla OXA-51-like carbapenemase genes (including six new variants), 40% harbored the bla OXA-23 carbapenemase gene, and 89% contained a variety of aminoglycoside resistance determinants with up to six unique determinants identified per strain. Many of the resistance determinants were found in potentially mobile gene cassettes; 45% and 7% of the isolates contained class 1 and class 2 integrons, respectively. Combined, the results demonstrate a facile approach that supports a more complete understanding of the genetic underpinnings of antimicrobial resistance to better assess the load, transmission, and evolution of MDR in MTF-associated A. baumannii.

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Genetic Context and Structural Diversity of Class 1 Integrons from Human Commensal Bacteria in a Hospital Intensive Care Unit

Cited by 34 publications

References 32 publications

Occurrences and Characterization of Antibiotic-Resistant Bacteria and Genetic Determinants of Hospital Wastewater in a Tropical Country

Occurrences and Characterization of Antibiotic-Resistant Bacteria and Genetic Determinants of Hospital Wastewater in a Tropical Country

Integrons: Past, Present, and Future

Antimicrobial Resistance Determinants in Acinetobacter baumannii Isolates Taken from Military Treatment Facilities

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