Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples

The aims of this study were to isolate and characterize Salmonella spp. from food sampled randomly from street vendors in Selangor, Malacca, Kuala Lumpur and Negeri Sembilan, and from clinical samples in a hospital in Klang, Selangor (collected from January to September 2004). A total of 24 Salmonel...

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Main Author:	Robin, Tunung
Format:	Thesis
Language:	English English
Published:	2006
Subjects:	Salmonella infections
Online Access:	http://psasir.upm.edu.my/id/eprint/5294/1/FSTM_2007_1.pdf
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spelling	my-upm-ir.52942013-05-27T07:21:46Z Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples 2006 Robin, Tunung The aims of this study were to isolate and characterize Salmonella spp. from food sampled randomly from street vendors in Selangor, Malacca, Kuala Lumpur and Negeri Sembilan, and from clinical samples in a hospital in Klang, Selangor (collected from January to September 2004). A total of 24 Salmonella strains, belonging to seven different serotypes, were isolated from 129 different street-vended foods and drinks and 12 rectal swabs from hospital patients suspected with salmonellosis. The most frequently encountered serotype from street foods was Salmonella Biafra (66.7%) while the most frequently encountered serotype from clinical samples was Salmonella Typhi (66.7%). To the best of our knowledge, this is the first reported occurence of Salmonella Biafra in street foods in Malaysia. Other serotypes isolated from street foods were Salmonella Braenderup (25%) and Salmonella Weltevreden (8.3%), and from clinical samples were Salmonella Typhimurium (17%), Salmonella Paratyphi A (0.08%) and Salmonella Paratyphi B (0.08%). All isolates were tested for their resistance to the following 14 antibiotics: streptomycin, trimethoprim, sulphamethoxazole, tetracycline, cefuroxime, ciprofloxacin, ampicillin, chloramphenicol, gentamicin, rifampin, penicillin, nalidixic acid, norfloxacin and erythromycin. All strains (100%) were found resistant to the antibiotic rifampin. None of the strains were however resistant to cefuroxime. A dendrogram was generated for antibiotic resistances of the isolates, and six clusters were defined, with similarity levels ranging from 18.8% to 100%. Generally, street foods and clinical isolates tend to cluster apart. A dendrogram to cluster the antibiotics was also generated, and they could be grouped according to their classes based on mode of inhibition: cell wall synthesis, protein synthesis, or nucleic acid synthesis. The most related compounds were chloramphenicol and tetracycline (46.6% similarity), which is acceptable as they share the same mode of inhibition. Ampicillin was grouped in the same cluster at 13.5% similarity although of different inhibition mode, possibly due to cross-resistance. Out of the 24 isolates screened for the presence of plasmid, 15 harbored plasmids. The plasmid sizes ranged from 3.0 to 38.5 MDa. Randomly amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus (ERIC) analysis were performed for the molecular genetic typing of the strains. RAPD fingerprinting with the primers OPAR3 and OPAR8 produced a combination of 21 fingerprint patterns, while ERIC fingerprinting generated 19 patterns. Cluster analysis of S. Biafra showed that similar serotypes were found in different food samples collected at different locations. The likely source of this result was cross contamination during food handling. Cluster analysis of S. Typhi showed that all the serotypes were different, even though the location of sampling was the same. The results indicate multiple source of S. Typhi infection of the patients. From this study, RAPD was found to be more discriminative than ERIC. Salmonella infections 2006 Thesis http://psasir.upm.edu.my/id/eprint/5294/ http://psasir.upm.edu.my/id/eprint/5294/1/FSTM_2007_1.pdf application/pdf en public masters Universiti Putra Malaysia Salmonella infections Food Science and Technology English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
topic	Salmonella infections
spellingShingle	Salmonella infections Robin, Tunung Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples
description	The aims of this study were to isolate and characterize Salmonella spp. from food sampled randomly from street vendors in Selangor, Malacca, Kuala Lumpur and Negeri Sembilan, and from clinical samples in a hospital in Klang, Selangor (collected from January to September 2004). A total of 24 Salmonella strains, belonging to seven different serotypes, were isolated from 129 different street-vended foods and drinks and 12 rectal swabs from hospital patients suspected with salmonellosis. The most frequently encountered serotype from street foods was Salmonella Biafra (66.7%) while the most frequently encountered serotype from clinical samples was Salmonella Typhi (66.7%). To the best of our knowledge, this is the first reported occurence of Salmonella Biafra in street foods in Malaysia. Other serotypes isolated from street foods were Salmonella Braenderup (25%) and Salmonella Weltevreden (8.3%), and from clinical samples were Salmonella Typhimurium (17%), Salmonella Paratyphi A (0.08%) and Salmonella Paratyphi B (0.08%). All isolates were tested for their resistance to the following 14 antibiotics: streptomycin, trimethoprim, sulphamethoxazole, tetracycline, cefuroxime, ciprofloxacin, ampicillin, chloramphenicol, gentamicin, rifampin, penicillin, nalidixic acid, norfloxacin and erythromycin. All strains (100%) were found resistant to the antibiotic rifampin. None of the strains were however resistant to cefuroxime. A dendrogram was generated for antibiotic resistances of the isolates, and six clusters were defined, with similarity levels ranging from 18.8% to 100%. Generally, street foods and clinical isolates tend to cluster apart. A dendrogram to cluster the antibiotics was also generated, and they could be grouped according to their classes based on mode of inhibition: cell wall synthesis, protein synthesis, or nucleic acid synthesis. The most related compounds were chloramphenicol and tetracycline (46.6% similarity), which is acceptable as they share the same mode of inhibition. Ampicillin was grouped in the same cluster at 13.5% similarity although of different inhibition mode, possibly due to cross-resistance. Out of the 24 isolates screened for the presence of plasmid, 15 harbored plasmids. The plasmid sizes ranged from 3.0 to 38.5 MDa. Randomly amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus (ERIC) analysis were performed for the molecular genetic typing of the strains. RAPD fingerprinting with the primers OPAR3 and OPAR8 produced a combination of 21 fingerprint patterns, while ERIC fingerprinting generated 19 patterns. Cluster analysis of S. Biafra showed that similar serotypes were found in different food samples collected at different locations. The likely source of this result was cross contamination during food handling. Cluster analysis of S. Typhi showed that all the serotypes were different, even though the location of sampling was the same. The results indicate multiple source of S. Typhi infection of the patients. From this study, RAPD was found to be more discriminative than ERIC.
format	Thesis
qualification_level	Master's degree
author	Robin, Tunung
author_facet	Robin, Tunung
author_sort	Robin, Tunung
title	Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples
title_short	Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples
title_full	Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples
title_fullStr	Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples
title_full_unstemmed	Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples
title_sort	isolation and characterization of salmonella species from street food and clinical samples
granting_institution	Universiti Putra Malaysia
granting_department	Food Science and Technology
publishDate	2006
url	http://psasir.upm.edu.my/id/eprint/5294/1/FSTM_2007_1.pdf
_version_	1747810393184534528

Isolation and Characterization of Salmonella Species from Street Food and Clinical Samples

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