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GENOMIC STUDIES OF REPRESENTATIVE PATHOGENIC MICROORGANISMS WITH REFERENCE TO RICKETTSIA PROWAZEKLL, STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI

JAMAL, SYED ASFAR (2007) GENOMIC STUDIES OF REPRESENTATIVE PATHOGENIC MICROORGANISMS WITH REFERENCE TO RICKETTSIA PROWAZEKLL, STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI. PhD thesis, University of Karachi, Karachi.

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Abstract

Staphylococcus aureus represents one of the most significant pathogens causing nosocomial and community acquired infections. Strains resistant to penicillinase resistant antibiotics such as oxacillin, methicillin and cloxacilin (MRSA) have also developed. MRSA are cross resistant to all B-lactamase inhibitor combinations. In this study 94 clinical isolates of Staphylococcus were collected from 72 patients. MIC of oxacillin and other important antibiotics were determined.48 of 94 isolates were MRSA, 28 were MSSA and 18 were methicillin resistant coagulase negative Staphylococcus. PCR based molecular typing of coagulase gene was done by restriction enzymes (RFLP analysis). We found eight different patterns in our study; five of them were novel PCR patterns that were not reported earlier. Out of 48 MRSA 25 (52.08%) are of same type indicating a nosocomial origin. The genes for 20 tRNA species in Rickettsia prowazekii have been cloned and sequenced. Two tRNA genes (thrT and tyrU) are located upstream of single tuf gene. The others exist as single transcription units. The genes for EF- TU, ribosomal protein operon S-10, IpxD, fabZ and IpxA were also sequenced. Escherichia coli is one of the major causes of human infections particularly urinary tract infection. In this study, 179 isolates were collected from different sources and their susceptibility pattern was studied. Highest resistance 89.9% was found against ampicillin whereas only 3.9% of isolate showed resistance to imipenam. 40.8% were also extended spectrum beta-Iactamase (ESBL) producers. Representative strains were also typed by enterobacterial repetitive intergenic consensus (ERIC) PCR. However due to variation in banding patterns ERIC-PCR was not found suitable for genotyping large number of E.coli isolates

Item Type:Thesis (PhD)
Uncontrolled Keywords:pathogenic microorganisms, rickettsia prowazekll, staphylococcus aureus, escherichia coli, nosocomial infections, community acquired infections, enterobacterial repetitive intergenic consensus, methicillin resistance
Subjects:Biological & Medical Sciences (c) > Biological Sciences(c1) > Microbiology(c1.8)
ID Code:2660
Deposited By:Mr. Javed Memon
Deposited On:20 Jul 2009 13:50
Last Modified:02 Aug 2010 11:40

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