Premium
Molecular characterization of antimicrobial resistance in Gram‐negative bacteria isolated from bovine mastitis in Egypt
Author(s) -
Ahmed Ashraf M.,
Shimamoto Tadashi
Publication year - 2011
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2011.00323.x
Subject(s) - biology , microbiology and biotechnology , citrobacter freundii , klebsiella pneumoniae , klebsiella oxytoca , antibiotic resistance , multiple drug resistance , enterobacter cloacae , trimethoprim , tigecycline , antimicrobial , drug resistance , virology , escherichia coli , antibiotics , genetics , gene
The aim of this study was to characterize the genetic basis of multidrug resistance in Gram‐negative bacteria isolated from bovine mastitis cases in Egypt. Multidrug resistance phenotypes were found in 34 of 112 (30.4%) Gram‐negative bacterial isolates, which harbored at least one antimicrobial resistance gene. The most prevalent multidrug‐resistant (MDR) species were Enterobacter cloacae (8 isolates, 7.1%), Klebsiella pneumoniae (7 isolates, 6.3%), Klebsiella oxytoca (7 isolates, 6.3%), Escherichia coli (5 isolates, 4.5%), and Citrobacter freundii (3 isolates, 2.7%). The most commonly observed resistance phenotypes were against ampicillin (97.0%), streptomycin (94.1%), tetracycline (91.2%), trimethoprim–sulfamethoxazole (88.2%), nalidixic acid (85.3%), and chloramphenicol (76.5%). Class 1 integrons were detected in 28 (25.0%) isolates. The gene cassettes within class 1 integrons included those encoding resistance to trimethoprim ( dfrA1, dfrA5, dfrA7, dfrA12, dfrA15, dfrA17 , and dfrA25 ), aminoglycosides ( aadA1, aadA2, aadA5, aadA7, aadA12 , aadA22 , and aac(3)‐Id ), chloramphenicol ( cmlA ), erythromycin ( ereA2 ), and rifampicin ( arr‐3 ). Class 2 integrons were identified in 6 isolates (5.4%) with three different profiles. Furthermore, the β‐lactamase encoding genes, bla TEM , bla SHV , bla CTX‐M , and bla OXA , the plasmid‐mediated quinolone resistance genes, qnr and aac(6)‐Ib‐cr , and the florfenicol resistance gene, floR , were also identified. To the best of our knowledge, the results identified class 2 integrons, qnr and aac(6)‐Ib‐cr from cases of mastitis for the first time. This is the first report of molecular characterization for antimicrobial resistance in Gram‐negative bacteria isolated from bovine mastitis in Africa.