TY  - THES
T1  - Prevalence, antimicrobial resistance and protein profiling of Salmonella spp. isolated from retail chicken and beef
A1  - Abu Bakar, Shafini
LA  - English
YR  - 2017
UL  - http://discoverylib.upm.edu.my/discovery/Record/oai:ethesis.upm.edu.my:12946
AB  - Presence of Salmonella spp. in meats, especially chicken and beef sold in the
market potentially creating issues related to food safety. Salmonella food
poisoning cases reported in Malaysia mostly involving chicken and beef based
dishes, had been confirmed from clinical samples. Commonly negative isolation
result obtained from food samples. In addition, presence of antimicrobial
resistance (AMR) Salmonella strains also resulting to ineffective patients’
treatment. Such factors bring to crucial selection on analytical methods that
determine the success of the Salmonella isolation in food samples. An
effectiveness of detection and identification methods is very important in
identifying Salmonella strains involved. Thus, the objectives of this study are to
verify the performance of immunomagnetic separation (IMS) method as an
alternative detection and isolation method for Salmonella spp. in chicken and
beef, to determine the prevalence of Salmonella spp. in samples from three
main retail markets, to determine antimicrobial resistance of Salmonella spp.
isolated from samples and to identify and characterize Salmonella spp. by
using Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)
technique. The IMS method evaluated and results of relative sensitivity 95.65%,
relative specificity 91.18% and relative accuracy 93.75% falls within acceptable
range according to Standard ISO 16140:2003 requirements. The prevalence
study was conducted using evaluated IMS method. A total of 156 chicken and
156 beef samples from wet market, butcher shop and supermarket were
collected from central region of Peninsular Malaysia and analysed. Highest
percentage of Salmonella detected in chicken (39.7%) compared to beef
(15.4%) samples. While on types of retail outlet, highest percentage of
Salmonella detected on samples from wet market (35.4%) followed by
supermarket (26.9%) and butcher shop (21.3%). From these three retail outlets,
unpacked chicken showed Salmonella percentage 26.8% higher than
unpacked beef (5.8%). While with packed samples showed Salmonella
percentage in range of 10.5% to 29.1% and 9.3% to 12.8% for chicken and
beef samples respectively. Out of 312 samples, 86 were positive with Salmonella spp. with 8 serovars identified as S.Enteritidis (38.4%), Salmonella
Hadar (25.6%), Salmonella Dublin (14.0%), Salmonella Stanley (7.0%),
Salmonella Gallinarium (7.0%), Salmonella Anatum (3.5%), Salmonella
Choleraesuis (2.3%) and Salmonella Typhimurium (2.3%). All 86 Salmonella
isolates demonstrated resistance to 14 types of antibiotics. Highest resistance
found towards Sulfonamides (88.4%) while intermediate resistant to
Gentamicin and susceptible to Ciprofloxaxin. Isolates from beef showed 100%
resistance toward antibiotics whereas only 95.2% on isolates from chicken.
Compared to other 7 Salmonella serovars, S. Enteritidis isolated from both
chicken and beef samples showed highest multidrug resistance (MDR) which
are resistant to 3 to 8 types of antibiotics. Due to faster, accurate result and
cost effective on identification process of Salmonella spp., MALDI-TOF
technique was chosen. From this technique, 8 serovars were successfully
identified, classified and clusterized. Specific information on peptide and
nucleotide sequences obtained from MALDI-TOF database may help in-depth
investigation on related species in future. Comprehensive data compiled
including the prevalence, antimicrobial resistance and protein profiling of
Salmonella spp. isolated from retail chicken and beef is valuable for future food
poisoning investigation incidents in Malaysia.
ER  -