I= GENOMIC STUDIES OF REPRESENTATIVE PATHOGENIC MICROORGANISMS WITH REFERENCE TO RICKETTSIA PROWAZEKLL, STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI
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Title of Thesis
GENOMIC STUDIES OF REPRESENTATIVE PATHOGENIC MICROORGANISMS WITH REFERENCE TO RICKETTSIA PROWAZEKLL, STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI

Author(s)
SYED ASFAR JAMAL
Institute/University/Department Details
Department of Microbiology/ University of Karachi
Session
2007
Subject
Microbiology
Number of Pages
68
Keywords (Extracted from title, table of contents and abstract of thesis)
pathogenic microorganisms, rickettsia prowazekll, staphylococcus aureus, escherichia coli, nosocomial infections, community acquired infections, enterobacterial repetitive intergenic consensus, methicillin resistance

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.

Download Full Thesis
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S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
203.63 KB
2 1 Introduction 1
305.91 KB
  1.1 General Introduction 1
  1.2 Staphylococcal Components And Products 2
  1.3 Genetic Regulation Of Virulence Determinant Expression 10
  1.4 Epidemiology Of Staphylococcal Disease 10
  1.5 Treatment Of Staphylococcus Aureus Infections 17
  1.6 Prevention Of Staphylococcal Diseases 18
  1.7 Antibiotic Resistance 19
  1.8 Molecular Mechanisms Of Methicillin Resistance 23
  1.9 Detection Of Methicillin Resistance In Staphylococcus Aureus And Other Species 25
  1.10 Typing 30
  1.11 Significance Of Work 37
3 2 Material And Methods 38
60.79 KB
  2.1 Bacterial Isolates 38
  2.2 Staphylococcus Aureus Identification Tests 38
  2.3 Detection Of Methicillin Resistance Staphylococcus Aureus (MRSA) And Methicillin Resistance Coagulase Negative Staphylococcus (MRCN) Species. 39
  2.4 Plasmid Profiling 40
  2.5 Beta- Iactamase Production 40
  2.6 Preparation Of Bacterial Iysates 40
  2.7 PCR Amplification Of Coa And Meca Genes 41
  2.8 PCR Amplification Of RFLP Of Coagulase Gene 42
  2.9 MIC Of Different Antibiotics 42
4 3 Results 43
319.46 KB
  3.1 Identification Of Staphylococcus Species 43
  3.2 Detection Of MRSA 43
  3.3 Production Of B- Iactomase 44
  3.4 Hemolysis 44
  3.5 Amplification Of Coa And Meca Gene Products 44
  3.6 Antibiogram 46
  3.7 RFLP Analysis Of Coagulase Gene 48
  3.8 Plasmid Analysis 55
5 4 Discussion 56
98.93 KB
6 5 References 68
1847.18 KB