ISOLATION AND ANTIBIOTIC SUSCEPTIBILITY PATTERN OF ESCHERICHIA COLI ISOLATES FROM STOOLS OF DIARRHOIEC CHILDREN BELOW 5 YEARS IN ZARIA, NIGERIA
ISOLATION AND ANTIBIOTIC SUSCEPTIBILITY PATTERN OF ESCHERICHIA COLI ISOLATES FROM STOOLS OF DIARRHOIEC CHILDREN BELOW 5 YEARS IN ZARIA, NIGERIA
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Date
2012-11
Authors
SUSAN, MOSEBOLATAN DAVID
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Abstract
ABSTRACT
E. coli has become widespread in distribution and recognised both as harmless commensal and a
versatile pathogen. It has emerged as an important cause of diarrhoea illness with diverse
phenotypes and pathogenicic mechanisms. E. coli and other members of the family
enterobacteriaceae are well known to develop or acquire resistance to a variety of antibiotics by
different mechanisms. Seventy (70) isolates of Escherichia coli from stool of diarrhoeic children
below five (5) years of age with suspected gastrointestinal infections attending two hospitals and
a primary health care centre in Zaria were screened for their susceptibility to a panel of nine
commonly used antibiotics by the disc diffusion method. Escherichia coli isolates which were
resistant to multiple antibiotics and showed minimum inhibitory concentration between 20 – 100
μg/ml against ciprofloxacin were used for conjugation studies. Curing experiments of the
transconjugants and resistant Escherichia coli isolates was carried out with acridine orange to
determine if the resistant determinants were plamid mediated . High level of resistance was
observed to Amoxicillin (100%), Ampicillin (100%), Tetracycline (100%),
Sulphamethoxazole/Trimethoprim (97.1%), Ceftazidime (88.6%), Cefuroxime (85.7%) while
lower resistance were observed to Gentamicin (35.7%), Ciprofloxacin (40%) and Ceftriaxone
(58.6%). Sixteen isolates (22.9%) were found to be resistant to all the 9 antibiotics used. Sixtyeight
isolates (97.1%) were identified as being resistant to multiple antibiotics since they were
simultaneously resistant to at least three different antibiotics with seventeen (17) different
phenotypic patterns. The multiple antibiotic resistance indices (MARI) for the MAR isolates was
found to be high, between 0.3 to 1.0 suggesting that the isolates originated from an environment
where antibiotics were often used. Plasmid DNA analysis on thirty-five resistant isolates showed
11 plasmid band sizes with molecular weights ranging from 2800 bp to > 5000 bp. Three
isolates were found to harbour the IncK epidemiologic plasmid encoding gene for the blaCTX-M of
the ESBLs and nineteen resistant isolates were also found to harbour the gyrB gene. The results
of this study indicates that resistance to ampicillin, amoxicillin and cotrimoxazole is remarkably
high in Zaria, and their continued usefulness in the treatment of E. coli infections in children
need to be reviewed. In contrast, gentamicin, ceftriaxone and ciprofloxacin were more
efficacious but the later (ciprofloxacin) is however contraindicated in children below 12 years of
age. Plasmid borne resistant genes among the Escherichia coli isolates were more from the
stools of children obtained from the General Hospital, Kofan-Gaya, Zaria-city, Nigeria.
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TABLE OF CONTENTS
COVER PAGE………………………………………….………………........................................i
FLY PAGE………………………………………………………………………………….......ii
TITLE PAGE………………………………………..………………………................………iii
DECLARATION .................................................................................................................................. iii
CERTIFICATION ................................................................................................................................. iv
DEDICATION ....................................................................................................................................... v
ACKNOWLEDGEMENTS .................................................................................................................... vi
ABSTRACT ........................................................................................................................................ viii
TABLE OF CONTENTS....................................................................................................................... ix
LIST OF FIGURES .............................................................................................................................. xiii
LIST OF TABLES ............................................................................................................................... xiv
LIST OF PLATES ................................................................................................................................ xv
CHAPTER ONE .................................................................................................................................... 1
1.0 INTRODUCTION ........................................................................................................................ 1
1.1 Diarrhoeal Diseases ....................................................................................................................... 1
1.2 Statement of research problem ..................................................................................................... 3
1.3 Justification of the Research ......................................................................................................... 4
1.4 Aim of the study ........................................................................................................................... 6
1.5 Specific objectives ........................................................................................................................ 6
1.6 Hypothesis .................................................................................................................................. 6
1.7 LIMITATIONS ............................................................................................................................ 7
CHAPTER TWO ................................................................................................................................... 8
2.0 LITERATURE REVIEW .............................................................................................................. 8
2.1 Diarrhoeal diseases ....................................................................................................................... 8
2.1.1 Defination, classification and distribution .................................................................................... 8
2.1.2 Causes of diarrhoea diseases ......................................................................................................... 9
2.1.3 Prevention of diarrhoea ............................................................................................................... 10
2.1.4 Management of diarrhoea ........................................................................................................... 10
2.2 ESCHERICHIA COLI................................................................................................................. 13
2.2.1 General characteristics ................................................................................................................. 13
2.2.2 Serotypes of E. coli ..................................................................................................................... 15
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2.2.3 Pathogenesis of Escherichia coli ................................................................................................. 15
2.2.4 Public health importance of E. coli ............................................................................................ 18
2.2.4.1 Faecal contamination .................................................................................................................. 18
2.2.4.2 E.coli as an indicator for antimicrobial resistance ..................................................................... 19
2.2.4.3 Emerging pathogen with potential to spread virulence ............................................................... 20
2.3.1 Penicillins and Cephalosporins ..................................................................................................... 21
2.3.1.1 Mechanism of action of the penicillins and cephalosporins ......................................................... 21
2.3.2 The cephalosporins ...................................................................................................................... 22
2.3.2.1 Classification of cephalosporins .................................................................................................. 22
2.3.3 Aminoglycosides ........................................................................................................................ 23
2.3.3.1 Mechanism of action of aminoglycosides .................................................................................... 24
2.3.4 Tetracyclines .............................................................................................................................. 24
2.3.4.1 Mechanism of action of tetracyclines .......................................................................................... 25
2.3.5 Trimethoprim-Sulfamethoxazole ................................................................................................ 25
2.3.5.1 Antibacterial Spectrum of sulfamethoxazole/trimethoprim .......................................................... 25
2.3.5.2 Mechanism of action of sulfamethoxazole/trimethoprim ............................................................. 26
2.3.6 Quinolones ............................................................................................................................... 26
2.3.6.1 Mechanism of Action of Quinolones ........................................................................................... 27
2.3.6.2 Antibacterial spectrum of quinolones .......................................................................................... 28
2.4 Antibiotic Resistance ...................................................................................................................... 29
2.4.1 Origin of Antimicrobial Resistance ............................................................................................. 30
2.4.1.1 Resistance spread ...................................................................................................................... 32
2.4.1.2 Persistence of resistance .......................................................................................................... 33
2.4.2 Mechanisms of bacterial resistance to penicillins and cephalosporins ........................................... 34
2.4.3 Mechanisms of bacterial resistance to the cephalosporins ............................................................ 35
2.4.4 Mechanism of bacterial resistance to the Tetracyclines ............................................................... 36
2.4.5 Bacterial Resistance to sulfamethoxazole/trimethoprim............................................................... 37
2.5 Extended Spectrum Beta Lactamase Production .......................................................................... 38
2.5.1 Genetics of ESBLS in E. coli ...................................................................................................... 38
2.5.2 Epidemiology of ESBL-producing E. coli in the community ....................................................... 39
2.6 Resistance to quinolones and fluoroquinolones ........................................................................... 43
2.6.1 Qnr proteins ............................................................................................................................... 44
2.7 Prevention of E. coli Infection ................................................................................................... 45
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CHAPTER
Description
A THESIS SUBMITTED TO THE
POSTGTRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
IN PARTIAL FULFILMENT OF THE REQUIRMENTS
FOR THE AWARD OF MASTER OF SCIENCE (M.Sc.) IN
PHARMACEUTICAL MICROBIOLOGY
Keywords
ISOLATION, ANTIBIOTIC, SUSCEPTIBILITY, PATTERN, ESCHERICHIA, COLI ISOLATES, STOOLS, DIARRHOIEC, CHILDREN BELOW, 5 YEARS IN ZARIA, NIGERIA