DETECTION AND MOLECULAR TYPING OF TOXINS OF Clostridium perfringens ISOLATES FROM SMALL RUMINANTS
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Date
2023-02
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SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA
Abstract
A study was carried out on the isolation, biochemical, molecular characterization
and toxin typing of C. perfringens isolated from healthy and diarrhoeic sheep and goat.
The antibiotic resistance pattern was studied in representative samples.
A total of 158 samples (rectal swabs and intestinal tissues) were collected from
healthy and diarrhoeic sheep and goat, from which 34 (21.51%) C. perfringens isolates
were obtained. A higher isolation rate was obtained from intestinal content samples
(67.65%) than faecal samples (32.35%). The samples that exhibited characteristic
cultural and biochemical characters were subjected to PCR, which revealed 34 samples
were positive for C. perfringens. The sugars like galactose, cellobiose and raffinose
were used to differentiate toxin type A, D and F from other toxin types, respectively.
Out of 34 positive samples, a high prevalence rate was observed among
diarrhoeic lambs (50.0%) followed by diarrhoeic sheep (44.12%) and healthy sheep
(5.88%). Multiplex PCR for six toxin genes (alpha, beta, epsilon, iota, entero and beta2)
of 34 isolates revealed the production of four toxins namely alpha, epsilon, entero and
beta2 toxins belonging to three toxin types i.e., type A, D and F. Out of these isolates,
30 (88.23%) isolates were characterized as C. perfringens type A, one (2.94%) isolate
was characterized as C. perfringens type D and three (8.82%) isolates were
characterized as C. perfringens type F. In the present study, C. perfringens type A was
found to be predominant among all the toxin types.
Among diarrhoeic sheep, 86.67% and 13.33% of C. perfringens type A and type
F were detected, respectively. The isolates obtained from healthy sheep were detected as
type A and among diarrhoeic lambs, 88.24%, 5.88% and 5.88% of type A, D and F were
detected, respectively.
Antibiogram of randomly selected isolates showed resistance to sulphamethizole
(66.67%) followed by co-trimoxazole (58.33%), enrofloxacin (41.67%) and tetracycline
(33.33%) and high sensitivity observed against gentamicin (91.67%) followed by
cefotaxime/clavulanic acid (91.67%), norfloxacin (91.67%) followed by
chloramphenicol (83.33%), cefotaxime (75.0%) and streptomycin (66.67%).
Sequencing results of selected isolates showed 100% homology with
corresponding published toxin genes confirming the amplicons as C. perfringens (481
bp), alpha (324 bp) and epsilon (376 bp) toxin genes of C. perfringens.
The present study concluded that the most of the isolates were characterized as
C. perfringens type A. Therefore, it may be recommended to include C. perfringens
type A anaculture in the existing vaccine, to prevent C. perfringens infections in this
geographic region (Krishna and West Godavari districts of Andhra Pradesh).
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