MOLECULAR CHARACTERIZATION OF Clostridium perfringens ISOLATED FROM ANIMALS AND HUMANS
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Date
2023-03
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SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA
Abstract
The present study was undertaken for isolation and characterization of
C. perfringens from animals, foods of animal origin and human samples. Out of 395
samples analyzed, 22.7% (90/395) were positive for C. perfringens by cultural isolation
and confirmation by biochemical tests. Out of 90 phenotypically positive C. perfringens
isolates from different sources, 34 (37.7%) isolates were further confirmed by species
specific PCR. The highest rate of occurrence of C. perfringens was detected in mutton
samples (18.1%) while lowest in human stool swab (5%) samples. All the C.
perfringens isolates (100%) showed lecithinase activity on egg yolk agar, 82.3%
isolates exhibited congo red binding activity, 73.5% isolates showed gelatinase activity
and 88.2% isolates showed hemolytic activity on sheep blood agar plates. Eight (23.5%)
C. perfringens isolates carried cpa gene indicating toxinotype A, four (11.7%) isolates
harboured both cpa and cpe genes indicating toxinotype F and three (8.8%) isolates
carried cpe gene alone. None of the isolates did not carry other three virulent genes like
etx, cpb and cpi.
Among 34 C. perfringens isolates higher resistance was observed towards
erythromycin, linezolid, metronidazole, pencillin G, rifampicin (100%), followed by
gentamicin (91.1%), tetracycline (88.2%), teicoplanin (85.2%), ciprofloxacin (73.5%)
and chloramphenicol (32.3%). The sensitivity percentages were highest against
imipenem (88.2%) followed by ceftriaxone (14.7%). Intermediate resistant patterns
were observed against ceftriaxone (85.2%), chloramphenicol (67.6%) and ciprofloxacin
(26.4%). All the 34 C. perfringens isolates were MDR and MAR indexing of all isolates
yielded 6 MAR index groups.
Out of 34 C. perfringens isolates 19 were identified as ESBL suspects by PST
and ESBL production was confirmed in ten isolates by CDM and in four isolates by
DDST. All the 19 phenotypic ESBL suspects did not carry any of the beta-lactamase
genes (blaTEM, blaSHV and blaOXA) by multiplex PCR.
A greater degree of heterogeneity was observed among 34 C. perfringens
isolates from different sources by ERIC and REP-PCR. ERIC-PCR distinguished 33
genotypes and REP-PCR distinguished 34 genotypes of C. perfringens isolates.
Genotyping of C. perfringens by ERIC-PCR and REP-PCR was highly significant since
the discriminatory power is >0.9 (0.998 for ERIC–PCR and 1 for REP-PCR). Cluster
analysis also revealed a greater degree of homogeneity and heterogeneity among
different isolates recovered from different sources indicating the chances of cross
contamination.