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Determination of
antibiotic susceptibility and fatty acid methyl ester
profiles of Bacillus cereus strains isolated from
different food sources in Turkey
Neslihan Dikbas
Atatürk
University, Biotechnology Research and Application Centre,
TR-25240 Erzurum/Turkey.
E-mail:
neslidikbas@atauni.edu.tr.
Tel: +90-442-2311439. Fax: +90-442-2360958.
Abbreviations: FAMEs, Fatty acid methyl esters;
FA, fatty acids; SDS-PAGE, sodium dodecyl
sulfate polyacrylamide gel electrophoresis; MIS,
microbial ıdentification system; NA, nutrient agar;
NB, nutrient broth; TSA, trypticase soy agar.
Accepted
19 February, 2010 |
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In this
study, a total of 77 Bacillus cereus isolates were
obtained from four different food samples (58 raw milks, 8
chickens, 7 cereals and 4 meats) consumed in Turkey by using
Chromogenic Bacillus Cereus Agar (Oxoid, CM1036). They were
tested for susceptibilities to a total of 10 different
antibiotics (penicillin, oxacillin, sulphamethoxazole,
rifampicin, apromycin, amikacin, tobramycin, kanamycin,
gentamicin and oflaxacin). In addition, they were determined
to be in fatty acid methyl esters (FAMEs) group of the
strains. All the isolates were identified as B. cereus
based on colonical, cellular morphology and biochemical
characters, including FAME analysis.
A total of 25 different fatty acids were detected in 77
strains tested, but 16 of them appeared as minor components,
in less than 2%. The strains had 15:0 iso 3OH (30.25%), 16:0
iso (11.23%), 17:0 iso (9.20%),16:0 (9.02%),13:0 iso
(8.85%), 14:0 iso (6.79%), 15:0 anteiso (4.83%), 14:0
(4.58%), 16:1
ω6c
(3.92%) and 16:1
ω7c
(3.92%) as the major fatty acids (FA).
Based on FAME analysis, the isolates were clustered into
three main groups.
Cluster 1, 2 and 3 were composed of the 71, 3 and 3 strains,
respectively. All the strains in each cluster showed an
extremely high degree of similarity (95 - 100%) to each
other.
Antibiotic resistant profile showed that all strains were
resistance to penicillin and oxacillin, but they were highly
susceptible to gentamicin and oflaxacin.
Key
words:
Antibiotic, Bacillus cereus, FAME, fatty acid, MIS,
resistance. |
