THE ROLE OF PLASMIDS IN ANTIBIOTIC SUSCEPTIBILITY OF LOCAL ISOLATES OF Klebsiella pneumoniae | ||
| Iraqi Journal of Biotechnology | ||
| Article 1, Volume 11, Issue 2, December 2012, Pages 481-493 | ||
| Author | ||
| Meelad A. Al-Nasiri | ||
| Abstract | ||
| Four local isolates of Klebsiella pneumoniae subsp. pneumoniae from different sources were tested towards twenty six antibiotic disks. The results showed that all selected isolates were sensitive to nalidixic acid, amikacin, and ciprofloxacin and the isolate MK6 showed further sensitivity to tetracycline, kanamycin, and streptomycin; but all isolates showed resistance toward the rest of antibiotics used. The minimal inhibitory concentration (MIC) test of four selected Klebsiella pneumoniae isolates (MK1, MK2, MK6 and MK20) to nine antibiotics showed the highest MIC values for the selected isolates were for amoxicillin and chloramphenicol (≥ 16384 µg/ml), while the lowest MIC was for streptomycin as it ranged from (8 – 16 µg/ml). Agarose gel electrophoresis was performed to detect plasmid profile for the four selected isolates. The results showed that all isolates exhibited two bands of small plasmid DNA with molecular size ranged from less than 4kb for the smaller one to more than 12kb for the larger one as compared with DNA of molecular size marker )lambda phage restricted with EcoRІ and HindIII). Besides two bands of large plasmid DNA were obtained from the isolates MK20, MK1, and MK6, but the isolate MK2 didn’t show any band of large plasmid DNA. This may be due to a technical error or to the low DNA concentration during extraction process In order to determine whether the plasmids of selected isolates play a role in antibiotic sensitivity, plasmid curing experiment was performed by using physical agent (elevated temperature). The results indicated that high temperature (47°C) was efficient to cure all the plasmids, and the isolates MK20, MK1, and MK2 became sensitive to streptomycin, kanamycin, and tetracycline. | ||
| Keywords | ||
| Klebsiella pneumoniae; MIC; Antibiotics | ||
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