TY - JOUR
T1 - Characterization of CTX-M ESBLs in Enterobacter cloacae, Escherichia coli and Klebsiella pneumoniae clinical isolates from Cairo, Egypt
AU - Khalaf, Noha G.
AU - Eletreby, Mona M.
AU - Hanson, Nancy D.
N1 - Funding Information:
We wish to thank Ellen Smith-Moland at the department of Microbiology and Immunology, Creighton University, Omaha, Nebraska for advice on the susceptibility testing, her valuable help in performing the isoelectric focusing experiments, and for her helpful discussions during the progress of the work. The Committee for Protection of Human Subjects at the medical institute has approved the scientific protocol and specimens were obtained from consenting patients. We thank George Jacoby for providing the Na azideR E. coli strain. Sequence data analysis was supported by a grant from the Binational Fulbright Commission (Egypt/USA).
PY - 2009/6/4
Y1 - 2009/6/4
N2 - Background: A high rate of resistance to 3rd generation cephalosporins among Enterobacteriaceae isolates from Egypt has been previously reported. This study aims to characterize the resistance mechanism (s) to extended spectrum cephalosporins among resistant clinical isolates at a medical institute in Cairo, Egypt. Methods: Nonconsecutive Klebsiella pneumoniae (Kp), Enterobacter cloacae (ENT) and Escherichia coli (EC) isolates were obtained from the clinical laboratory at the medical institute. Antibiotic susceptibility was tested by CLSI disk diffusion and ESBL confirmatory tests. MICs were determined using broth microdilution. Isoelectric focusing (IEF) was used to determine the pI values, inhibitor profiles, and cefotaxime (CTX) hydrolysis by the β-lactamases. PCR and sequencing were performed using blaCTX-M and ISEcp1-specific primers, with DNA obtained from the clinical isolates. Conjugation experiments were done to determine the mobility of blaCTX-M. Results: All five clinical isolates were resistant to CTX, and were positive for ESBL screening. IEF revealed multiple β-lactamases produced by each isolate, including a β-lactamase with a pI of 8.0 in Kp and ENT and a β-lactamase with a pI of 9.0 in EC. Both β-lactamases were inhibited by clavulanic acid and hydrolyzed CTX. PCR and sequence analysis identified blaCTX-M-14. in Kp and ENT and a blaCTX-M-15 in EC. Both blaCTX-M-14 and blaCTX-M-15 were preceded by ISEcp1 elements as revealed by partial sequence analysis of the upstream region of the blaCTX-M genes. blaCTX-M-15 was transferable but not blaCTX-M-14. Conclusion: This is the first report of CTX-M-14 in Kp and ENT isolates from Egypt, the Middle East and North Africa.
AB - Background: A high rate of resistance to 3rd generation cephalosporins among Enterobacteriaceae isolates from Egypt has been previously reported. This study aims to characterize the resistance mechanism (s) to extended spectrum cephalosporins among resistant clinical isolates at a medical institute in Cairo, Egypt. Methods: Nonconsecutive Klebsiella pneumoniae (Kp), Enterobacter cloacae (ENT) and Escherichia coli (EC) isolates were obtained from the clinical laboratory at the medical institute. Antibiotic susceptibility was tested by CLSI disk diffusion and ESBL confirmatory tests. MICs were determined using broth microdilution. Isoelectric focusing (IEF) was used to determine the pI values, inhibitor profiles, and cefotaxime (CTX) hydrolysis by the β-lactamases. PCR and sequencing were performed using blaCTX-M and ISEcp1-specific primers, with DNA obtained from the clinical isolates. Conjugation experiments were done to determine the mobility of blaCTX-M. Results: All five clinical isolates were resistant to CTX, and were positive for ESBL screening. IEF revealed multiple β-lactamases produced by each isolate, including a β-lactamase with a pI of 8.0 in Kp and ENT and a β-lactamase with a pI of 9.0 in EC. Both β-lactamases were inhibited by clavulanic acid and hydrolyzed CTX. PCR and sequence analysis identified blaCTX-M-14. in Kp and ENT and a blaCTX-M-15 in EC. Both blaCTX-M-14 and blaCTX-M-15 were preceded by ISEcp1 elements as revealed by partial sequence analysis of the upstream region of the blaCTX-M genes. blaCTX-M-15 was transferable but not blaCTX-M-14. Conclusion: This is the first report of CTX-M-14 in Kp and ENT isolates from Egypt, the Middle East and North Africa.
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U2 - 10.1186/1471-2334-9-84
DO - 10.1186/1471-2334-9-84
M3 - Article
C2 - 19497111
AN - SCOPUS:67649848125
VL - 9
JO - BMC Infectious Diseases
JF - BMC Infectious Diseases
SN - 1471-2334
M1 - 84
ER -