Plasmid-mediated extended-spectrum β-lactamases in organisms other than Klebsiella pneumoniae and Escherichia coli: A hidden reservoir of transferable resistance genes

2002 ◽  
Vol 4 (3) ◽  
pp. 181-183 ◽  
Author(s):  
Matthew E. Levison
2011 ◽  
Vol 3 (01) ◽  
pp. 037-042 ◽  
Author(s):  
Varsha K Vaidya

ABSTRACT Background: The purpose of this work was to study the acquisition of new antibiotic-resistant genes carried by extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae via horizontal transfer to understand their rampant spread in the hospitals and in the community. Materials and Methods: A retrospective analysis of 120 ESBL screen-positive isolates of Escherichia coli and Klebsiella pneumoniae, which were subjected to antimicrobial susceptibility testing, was carried out. The Double Disc Synergy Test (DDST) and Inhibitor-Potentiation Disc Diffusion Test (IPDD) were employed for confirmation of ESBL activity. The transferability of the associated antibiotic resistance for amoxicillin, amikacin, gentamicin, cefotaxime and ceftriaxone was elucidated by intra- and intergenus conjugation in Escherichia coli under laboratory as well as under simulated environmental conditions. Transformation experiments using plasmids isolated by alkaline lysis method were performed to study the transferability of resistance genes in Klebsiella pneumoniae isolates. Results : ESBL production was indicated in 20% each of the Escherichia coli and Klebsiella pneumoniae isolates. All the ESBL isolates showed co- resistance to various other groups of antibiotics, including 3GC antibiotics, though all the isolates were sensitive to both the carbapenems tested. Conjugation-mediated transfer of resistance under laboratory as well as environmental conditions at a frequency of 3-4 x 10-5 , and transformation-mediated dissemination of cefotaxime and gentamicin resistance shed light on the propensity of ESBL producers for horizontal transfer. Conclusions: The transfer of resistant markers indicated availability of a large pool of resistance genes in the hospital setting as well as in the environment, facilitating long-term persistence of organisms.


2017 ◽  
Author(s):  
JJ van Aartsen ◽  
CE Moore ◽  
CM Parry ◽  
P Turner ◽  
N Phot ◽  
...  

ABSTRACTExtended-spectrum cephalosporin resistance (ESC-R) in Escherichia coli and Klebsiella pneumoniae is a healthcare threat; high gastrointestinal carriage rates are reported from South-east Asia. Colonisation prevalence data in Cambodia are lacking. We determined gastrointestinal colonisation prevalence of ESC-resistant E. coli (ESC-R-EC) and K. pneumoniae (ESC-R-KP) in Cambodian children/adolescents and associated risk factors; characterised relevant resistance genes, their genetic contexts, and the genetic relatedness of ESC-R strains using whole genome sequencing (WGS). Faeces and questionnaire data were obtained from individuals <16 years in northwestern Cambodia, 2012. WGS of cultured ESC-R-EC/KP was performed (Illumina). Maximum likelihood phylogenies were used to characterise relatedness of isolates; ESC-R-associated resistance genes and their genetic contexts were identified from de novo assemblies using BLASTn and automated/manual annotation. 82/148 (55%) of children/adolescents were ESC-R-EC/KP colonised; 12/148 (8%) were co-colonised with both species. Independent risk factors for colonisation were hospitalisation (OR: 3.12, 95%, CI [1.52-6.38]) and intestinal parasites (OR: 3.11 [1.29-7.51]); school attendance conferred decreased risk (OR: 0.44 [0.21-0.92]. ESC-R strains were diverse; the commonest ESC-R mechanisms were blaCTX-M 1 and 9 sub-family variants. Structures flanking these genes were highly variable, and for blaCTX-M-15,-55and-27, frequently involved IS26. Chromosomal blaCTX-M integration was common in E. coli. Gastrointestinal ESC-R-EC/KP colonisation is widespread in Cambodian children/adolescents; hospital admission and intestinal parasites are independent risk factors. The genetic contexts of blaCTX-M are highly mosaic, consistent with rapid horizontal exchange. Chromosomal integration of blaCTX-M may result in stable propagation in these community-associated pathogens.


Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 850
Author(s):  
Shobha Giri ◽  
Vaishnavi Kudva ◽  
Kalidas Shetty ◽  
Veena Shetty

As the global urban populations increase with rapid migration from rural areas, ready-to-eat (RTE) street foods are posing food safety challenges where street foods are prepared with less structured food safety guidelines in small and roadside outlets. The increased presence of extended-spectrum-β-lactamase (ESBL) producing bacteria in street foods is a significant risk for human health because of its epidemiological significance. Escherichia coli and Klebsiella pneumoniae have become important and dangerous foodborne pathogens globally for their relevance to antibiotic resistance. The present study was undertaken to evaluate the potential burden of antibiotic-resistant E. coli and K. pneumoniae contaminating RTE street foods and to assess the microbiological quality of foods in a typical emerging and growing urban suburb of India where RTE street foods are rapidly establishing with public health implications. A total of 100 RTE food samples were collected of which, 22.88% were E. coli and 27.12% K. pneumoniae. The prevalence of ESBL-producing E. coli and K. pneumoniae was 25.42%, isolated mostly from chutneys, salads, paani puri, and chicken. Antimicrobial resistance was observed towards cefepime (72.9%), imipenem (55.9%), cefotaxime (52.5%), and meropenem (16.9%) with 86.44% of the isolates with MAR index above 0.22. Among β-lactamase encoding genes, blaTEM (40.68%) was the most prevalent followed by blaCTX (32.20%) and blaSHV (10.17%). blaNDM gene was detected in 20.34% of the isolates. This study indicated that contaminated RTE street foods present health risks to consumers and there is a high potential of transferring multi-drug-resistant bacteria from foods to humans and from person to person as pathogens or as commensal residents of the human gut leading to challenges for subsequent therapeutic treatments.


2011 ◽  
Vol 60 (9) ◽  
pp. 1344-1352 ◽  
Author(s):  
Abouddihaj Barguigua ◽  
Fatima El Otmani ◽  
Mustapha Talmi ◽  
Fatna Bourjilat ◽  
Fatima Haouzane ◽  
...  

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