| Alireza Japoni-Nejad | 2 Articles |
Objectives
Plasmid-mediated AmpC β-lactamases (PMABLs) and carbapenemases are emerging groups of antimicrobial-resistance determinants. The aims of the study were to evaluate the occurrence of PMABLs and carbapenemases in clinical isolates of <i>Klebsiella pneumoniae</i> and compare the test performance of various phenotypic methods for detection of these enzymes in Iran. Methods A total of 100 <i>K. pneumoniae</i> isolates were collected from clinical specimens obtained in Valiasr Hospital. AmpC production in all isolates was determined using the AmpC disk test, the cephamycin Hodge test, the AmpC Etest, and the boronic acid combined-disk test. In addition, carbapenemase production was determined using the modified Hodge test, the EDTA disk synergy test, and the boronic acid combined-disk test. The performances of various phenotypic methods were evaluated by the comparison of their results with polymerase chain reaction (PCR) method as the gold standard. Results Of the 100 isolates, 19 (19%) were demonstrated to harbor the PMABL-resistance gene by the multiplex PCR method. The PCR result indicated the presence of carbapenemase genes in 12 isolates. The performance of various phenotypic tests carried out for detection of carbapenemase-producing isolates varied widely, ranging in sensitivity from 30% to 100% and in specificity from 90.8% to 100%. Conclusion This is the first report of <i>MOX</i>-type AmpC β-lactamase and <i>bla</i><sub><i>GES</i></sub> in <i>K. pneumoniae</i> in Iran. A comparison of the phenotypic methods showed that a combination of cefoxitin plus boronic acid is optimal for detecting plasmid-mediated AmpC enzymes in <i>K. pneumoniae</i>, whereas the implementation of molecular methods is often complex, requires specially trained personnel, and is associated with higher costs. Citations
Citations to this article as recorded by
Objectives
Horizontal transfer of integrons is one of the important factors that can contribute to the occurrence of multidrug-resistant (MDR) bacteria. This study aimed to determine the prevalence of integrons among MDR <i>Escherichia coli</i> strains isolated from stool specimens and investigate the associations between the existence of integrons and MDR properties in the southwest of Iran. Methods There were 164 <i>E. coli</i> strains isolated from January 2012 to June 2012. Fecal specimens identified as <i>E. coli</i> by the conventional methods. Subsequently the antibiotic resistance was assessed using Clinical and Laboratory Standard Institute criteria. The presence of class 1–3 integrons and embedded gene cassettes was verified using specific primers by multiplex polymerase chain reaction assay. Results Among a total of 164 studied samples, 69 (42.07%) isolates were multidrug resistant. Class 1 and class 2 integrons were present in 78.26% and 76.81% MDR isolates, respectively. For the first time in Iran, class 3 integron was observed in 26.09% MDR isolates. Significant correlations were identified between: class 1 integron and resistance to amikacin, gentamicin, chloramphenicol, ampicillin, tetracycline, nalidixic acid, and co-trimoxazole; class 2 integron and resistance to aminoglycosides, co-trimoxazole, cefalexin, ampicillin, and chloramphenicol; and class 3 integron and resistance to gentamicin, kanamycin, and streptomycin. Conclusion Our results indicate that integrons are common among MDR isolates and they can be used as a marker for the identification of MDR isolates. Therefore, due to the possibility of a widespread outbreak of MDR isolates, molecular surveillance and sequencing of the integrons in other parts of the country is recommended. Citations
Citations to this article as recorded by
|
|
