Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM

Coagulase-Negative Staphylococci (CoNS) is a group of microorganisms that are increasingly implicated as a cause of significant infection and has emerged as the most frequent cause of nosocomial bloodstream infection. CoNS species are nonnal skin flora and, it can be difficult to determine if CoN...

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Main Author:	Hamzah, Siti Hawa
Format:	Thesis
Language:	English
Published:	2010
Subjects:	QR75-99.5 Bacteria
Online Access:	http://eprints.usm.my/58928/1/DR%20SITI%20HAWA%20BINTI%20HAMZAH%20-%20e24.pdf
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spelling	my-usm-ep.589282023-08-17T04:54:33Z Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM 2010 Hamzah, Siti Hawa QR75-99.5 Bacteria Coagulase-Negative Staphylococci (CoNS) is a group of microorganisms that are increasingly implicated as a cause of significant infection and has emerged as the most frequent cause of nosocomial bloodstream infection. CoNS species are nonnal skin flora and, it can be difficult to determine if CoNS species isolated from blood cultures reflect infection or microbial contamination. At the moment, pulsed-field gel electrophoresis (PFGE) is considered as a gold standard to diagnose the significance of CoNS isolated from blood cultures. In this study, significance of repeated CoNS isolated from blood cultures were evaluated by species identification, antibiogram and a molecular method, PFGE. A total of 101 pairs of Coagulase-Negative Staphylococci were analyzed during this period of study. These isolates were identified to the species level by API Staph ID. Out of 101 pairs(, only 84 pairs (83.1%) of CoNs identified were similar species. These 84 pairs were further analyzed by pulsed-field gel electrophoresis (PFGE) to detennine its clonality (genotypic). However only 33 pairs had eligible PFGE result for interpretation In this study, Staphylococcus epidermidis was the predominant species isolated (52.5%), followed by S.capitis (10.4%) and S.chromogenes (1.9%). The percentage of methicillinresistant CoNS was higher (68.68%) as compared to methicillin-sensitive CoNS. The percentage of same phenotype with same antibiogram pattern (40.7%) was lower as compared to same phenotype and different antibiogram pattern (59.3%). There was a significant association between same phenotype and same antibiogram pattern. Out of 33 pairs of CoNS analyzed, 87.9% (29 pairs) had indistinguishable patterns which denote the same bacterial strains. However the association between phenotypic and genotypic cannot be made because due to failure to maintain reproducible PFGE results, hence resulted in insignificant statistical findings. Overall laboratory concordance case was defined as a case which were concordant for the triple tests conducted: phenotypic, antibiogram pattern and genotypic. Out of 33 pairs of CoNS with PFGE results, 14 cases (42.4%) were concordant cases which represent laboratory true bacteraemia and 19 cases (57.6%) were regarded as contaminants. In this study, there was significant association between same phenotype and antibiotic treatment. The percentage of those who had antibiotic treatment and same phenotype was higher (90.9%) as compared to those without antibiotic treatment (9.1%). There was significant association for leukocyte count, nosocomial infection and antibiotic treatment with antibiogram pattern. The association of laboratory concordance cases with clinical parameters showed significant association between laboratory concordance cases with blood pressure, leukocyte count and antibiotic treatment. All clinical parameters were not significantly associated with concordance genotype. The outcome of this study showed that genotype by pulsed-field gel electrophoresis (PFGE) failed to show any association with clinical bacteraemia by statistical calculation due to small sample size 2010 Thesis http://eprints.usm.my/58928/ http://eprints.usm.my/58928/1/DR%20SITI%20HAWA%20BINTI%20HAMZAH%20-%20e24.pdf application/pdf en public masters Universiti Sains Malaysia Pusat Pengajian Sains Perubatan
institution	Universiti Sains Malaysia
collection	USM Institutional Repository
language	English
topic	QR75-99.5 Bacteria
spellingShingle	QR75-99.5 Bacteria Hamzah, Siti Hawa Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM
description	Coagulase-Negative Staphylococci (CoNS) is a group of microorganisms that are increasingly implicated as a cause of significant infection and has emerged as the most frequent cause of nosocomial bloodstream infection. CoNS species are nonnal skin flora and, it can be difficult to determine if CoNS species isolated from blood cultures reflect infection or microbial contamination. At the moment, pulsed-field gel electrophoresis (PFGE) is considered as a gold standard to diagnose the significance of CoNS isolated from blood cultures. In this study, significance of repeated CoNS isolated from blood cultures were evaluated by species identification, antibiogram and a molecular method, PFGE. A total of 101 pairs of Coagulase-Negative Staphylococci were analyzed during this period of study. These isolates were identified to the species level by API Staph ID. Out of 101 pairs(, only 84 pairs (83.1%) of CoNs identified were similar species. These 84 pairs were further analyzed by pulsed-field gel electrophoresis (PFGE) to detennine its clonality (genotypic). However only 33 pairs had eligible PFGE result for interpretation In this study, Staphylococcus epidermidis was the predominant species isolated (52.5%), followed by S.capitis (10.4%) and S.chromogenes (1.9%). The percentage of methicillinresistant CoNS was higher (68.68%) as compared to methicillin-sensitive CoNS. The percentage of same phenotype with same antibiogram pattern (40.7%) was lower as compared to same phenotype and different antibiogram pattern (59.3%). There was a significant association between same phenotype and same antibiogram pattern. Out of 33 pairs of CoNS analyzed, 87.9% (29 pairs) had indistinguishable patterns which denote the same bacterial strains. However the association between phenotypic and genotypic cannot be made because due to failure to maintain reproducible PFGE results, hence resulted in insignificant statistical findings. Overall laboratory concordance case was defined as a case which were concordant for the triple tests conducted: phenotypic, antibiogram pattern and genotypic. Out of 33 pairs of CoNS with PFGE results, 14 cases (42.4%) were concordant cases which represent laboratory true bacteraemia and 19 cases (57.6%) were regarded as contaminants. In this study, there was significant association between same phenotype and antibiotic treatment. The percentage of those who had antibiotic treatment and same phenotype was higher (90.9%) as compared to those without antibiotic treatment (9.1%). There was significant association for leukocyte count, nosocomial infection and antibiotic treatment with antibiogram pattern. The association of laboratory concordance cases with clinical parameters showed significant association between laboratory concordance cases with blood pressure, leukocyte count and antibiotic treatment. All clinical parameters were not significantly associated with concordance genotype. The outcome of this study showed that genotype by pulsed-field gel electrophoresis (PFGE) failed to show any association with clinical bacteraemia by statistical calculation due to small sample size
format	Thesis
qualification_level	Master's degree
author	Hamzah, Siti Hawa
author_facet	Hamzah, Siti Hawa
author_sort	Hamzah, Siti Hawa
title	Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM
title_short	Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM
title_full	Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM
title_fullStr	Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM
title_full_unstemmed	Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM
title_sort	determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in husm
granting_institution	Universiti Sains Malaysia
granting_department	Pusat Pengajian Sains Perubatan
publishDate	2010
url	http://eprints.usm.my/58928/1/DR%20SITI%20HAWA%20BINTI%20HAMZAH%20-%20e24.pdf
_version_	1776101245530931200

Determining the clonality and significance of coagulase-negative staphylococci isolated from blood cultures in HUSM

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