Please use this identifier to cite or link to this item: http://cuir.car.chula.ac.th/handle/123456789/56913
Title: Characterization of extended-spectrum β-lactamase and ampc β-lactamase genes in nontyphoidal salmonella clinical isolates in Thailand
Other Titles: คุณลักษณะของยีนที่สร้างเอ็นไซม์ Extended-spectrum β-lactamases และ AmpC β-lactamases ในเชื้อ Nontyphoidal Salmonella ที่แยกได้จากผู้ป่วยในประเทศไทย
Authors: Sirirat Luk-in
Advisors: Tanittha Chatsuwan
Wanla Kulwichit
Other author: Chulalongkorn University. Graduate School
Advisor's Email: Tanittha.C@Chula.ac.th
Wanla.K@Chula.ac.th
Subjects: Salmonella
Genes
Drug resistance in microorganisms
ซาลโมเนลลา
การดื้อยาในจุลินทรีย์
ยีน
Issue Date: 2009
Publisher: Chulalongkorn University
Abstract: The production of extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases in nontyphoidal Salmonella are increasingly reported worldwide and pose a serious threat for salmonellosis. Nevertheless, no prevalence data on ESBLs and AmpC β-lactamases in nontyphoidal Salmonella in Thailand have been reported. This study characterized genes encoding ESBLs and plasmid-mediated AmpC β-lactamases and investigated the prevalence of extended-spectrum cephalosporin (ESC) resistance in nontyphoidal Salmonella isolates. A total of 560 nontyphoidal Salmonella isolated from patients during 2005-2007 were included in this study. The resistance rates to cefoxitin, ceftazidime, cefotaxime, and ceftriaxone were 11.79%, 14.64%, 9.46%, and 12.50%, respectively. A total of 119 ESC-resistant isolates were detected for ESBL and AmpC phenotypes. The results showed that 52 isolates (43.70%), 66 isolates (55.46%), and 1 isolate (0.84%) were ESBL producers, AmpC producers, and ESBL and AmpC co-producer, respectively. Screening for the presence of bla genes revealed that 66 isolates (55.46%) carried blaCIT-like followed by 31 isolates (26.05%) with blaCTX-M-9 group, 14 isolates (11.76%) with blaCTX-M-1 group together with blaTEM-like, 7 isolates (5.88%) with blaCTX-M-9 group together with blaTEM-like, and 1 isolate (0.84%) with blaCTX-M-9 group blaTEM-like and blaCIT-like. DNA sequencing analysis of the entire bla genes from representative isolates showed that of the 14 blaCTX-M-1 group, 13 were blaCTX-M-55 and one was blaCTX-M-15 whereas all 10 blaCTX-M-9 group, 22 blaTEM-like, and 10 blaCIT-like were blaCTX-M-14, blaTEM-1, and blaCMY-2, respectively. ISEcp1 was present in the upstream regions of blaCTX-M and blaCIT in all isolates. ISEcp1-mediated -35 and -10 promoter sequences were found in all 34 representative isolates. This is the first report of the prevalence of ESBLs and plasmid-mediated AmpC β-lactamases in nontyphoidal Salmonella isolates in Thailand. Our results showed that the high rate of ESC resistance was attributed to the production of CTX-M-type ESBL and plasmid-mediated AmpC which CTX-M-9 group ESBLs and CIT-type AmpC were the most frequent β-lactamases. This was the first report of CTX-M-14 in S. Choleraesuis and also the first report of co-carrying CMY-2, CTX-M-14, and TEM-1 in nontyphoidal Salmonella.
Other Abstract: The production of extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases in nontyphoidal Salmonella are increasingly reported worldwide and pose a serious threat for salmonellosis. Nevertheless, no prevalence data on ESBLs and AmpC β-lactamases in nontyphoidal Salmonella in Thailand have been reported. This study characterized genes encoding ESBLs and plasmid-mediated AmpC β-lactamases and investigated the prevalence of extended-spectrum cephalosporin (ESC) resistance in nontyphoidal Salmonella isolates. A total of 560 nontyphoidal Salmonella isolated from patients during 2005-2007 were included in this study. The resistance rates to cefoxitin, ceftazidime, cefotaxime, and ceftriaxone were 11.79%, 14.64%, 9.46%, and 12.50%, respectively. A total of 119 ESC-resistant isolates were detected for ESBL and AmpC phenotypes. The results showed that 52 isolates (43.70%), 66 isolates (55.46%), and 1 isolate (0.84%) were ESBL producers, AmpC producers, and ESBL and AmpC co-producer, respectively. Screening for the presence of bla genes revealed that 66 isolates (55.46%) carried blaCIT-like followed by 31 isolates (26.05%) with blaCTX-M-9 group, 14 isolates (11.76%) with blaCTX-M-1 group together with blaTEM-like, 7 isolates (5.88%) with blaCTX-M-9 group together with blaTEM-like, and 1 isolate (0.84%) with blaCTX-M-9 group blaTEM-like and blaCIT-like. DNA sequencing analysis of the entire bla genes from representative isolates showed that of the 14 blaCTX-M-1 group, 13 were blaCTX-M-55 and one was blaCTX-M-15 whereas all 10 blaCTX-M-9 group, 22 blaTEM-like, and 10 blaCIT-like were blaCTX-M-14, blaTEM-1, and blaCMY-2, respectively. ISEcp1 was present in the upstream regions of blaCTX-M and blaCIT in all isolates. ISEcp1-mediated -35 and -10 promoter sequences were found in all 34 representative isolates. This is the first report of the prevalence of ESBLs and plasmid-mediated AmpC β-lactamases in nontyphoidal Salmonella isolates in Thailand. Our results showed that the high rate of ESC resistance was attributed to the production of CTX-M-type ESBL and plasmid-mediated AmpC which CTX-M-9 group ESBLs and CIT-type AmpC were the most frequent β-lactamases. This was the first report of CTX-M-14 in S. Choleraesuis and also the first report of co-carrying CMY-2, CTX-M-14, and TEM-1 in nontyphoidal Salmonella.
Description: Thesis (M.Sc.)--Chulalongkorn University, 2009
Degree Name: Master of Science
Degree Level: Master's Degree
Degree Discipline: Medical Microbiology (Inter-Department)
URI: http://cuir.car.chula.ac.th/handle/123456789/56913
URI: http://doi.org/10.14457/CU.the.2009.1596
metadata.dc.identifier.DOI: 10.14457/CU.the.2009.1596
Type: Thesis
Appears in Collections:Grad - Theses

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