STUDIES ON Arcobacter SPECIES OF ANIMAL AND HUMAN ORIGIN
Loading...
Date
2016-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI – 517 502. (A.P) INDIA
Abstract
ABSTRACT:
Arcobacter is an emerging foodborne pathogen having worldwide public health
concern. The present study was undertaken to characterize Arcobacter species of animal
and human origin based on cultural isolation, PCR detection, antibiogram, virulence
profiles and genetic diversity. A total of 510 samples comprising faecal swabs of
livestock (245), raw foods of animal origin (180) and human stools (85) were examined.
Overall prevalence of Arcobacter species was found to be 11.7% (60/510) by
genus-specific PCR. Among faecal samples of healthy livestock, pigs (23.3%) revealed
the highest prevalence, followed by chicken (16.6%), turkey (15.0%), cattle (10.0%),
duck (10.0%) and sheep (6.6%). Among foods of animal origin, pork samples (15.0%)
revealed the highest prevalence, followed by chicken meat (12.5%), milk (10.0%) and
mutton (7.5%). Among human stool samples, farm workers revealed highest prevalence
(13.3%, 4/30) followed by veterinary students (8.0%, 2/25) and diarrhoeic humans
(6.66%, 2/30). Out of 60 genus-specific PCR positive samples, multiplex-PCR assay
enabled detection of A. butzleri (16/60), A. cryaerophilus (10/60), A. skirrowii (10/60),
both A. cryaerophilus and A. skirrowii (9/60), both A. butzleri and A. skirrowii (5/60),
both A. butzleri and A. cryaerophilus (4/60) and all the three Arcobacter species (6/60).
Using cultural methods, a total of 41 (8.03%) Arcobacter isolates were recovered.
Multiplex-PCR assay of 41 Arcobacter isolates enabled detection of A. butzleri (16/41),
A. cryaerophilus (13/41) and A. skirrowii (12/41). All the A. butzleri isolates carried all six putative virulence genes. For A.
cryaerophilus and A. skirrowii, the cadF gene was detected in 61.5% and 50%, ciaB in
84.6% and 91.6%, cj1349 in 76.9% and 83.3%, mviN in 76.9% and 66.6%, pldA in 61.5%
and 50% and tlyA in 61.5% and 50% of isolates, respectively.
Antibiogram of Arcobacter isolates revealed sensitivity to tetracycline (100%),
ciprofloxacin (95.1%) and gentamicin (82.9%). Higher resistance was observed for
vancomycin (100%), co-trimoxazole (87.8%), chloramphenicol (78%) and erythromycin
(51.2%) with remarkable intermediate resistance against kanamycin (68.2%), nalidixic
acid (53.6%) and cefoxitin (43.9%). Resistance to β-lactam antibiotics like aztreonam
(65.8%), cefotaxime (63.4%), ceftazidime (58.5%) and ceftriaxone (53.6%) was detected.
An ESBL phenotype was confirmed in a total of 15 Arcobacter isolates. β-lactamase
genes were detected in 63.4% of Arcobacter isolates, with blaTEM being the predominant
gene detected (51.2%, 21/41) followed by blaCTX-M group 1 (36.5%, 15/41), blaAmpC
(29.2%, 12/41), blaOXA (29.2%, 12/41), blaSHV (14.6%, 6/41) and blaCTX-M group 2
(14.6%, 6/41). CTX-M beta-lactamase was found to be the most frequent mechanism of
ESBL resistance in Arcobacter isolates. ERIC PCR and rep-PCR analysis revealed a greater degree of heterogeneity
among Arcobacter isolates from different sources. ERIC-PCR genotyping distinguished
14, 13 and 12 genotypes among 16, 13 and 12 isolates of A. butzleri, A. cryaerophilus
and A. skirrowii, respectively. Rep-PCR genotyping distinguished 15, 12 and 11
genotypes among 16, 13 and 12 isolates of A. butzleri, A. cryaerophilus and A. skirrowii,
respectively. The discriminatory power ERIC-PCR and rep-PCR for Arcobacter isolates
was found to be 0.997 and 0.996, respectively. Genetic diversity of A. butzleri, A.
cryaerophilus and A. skirrowii recovered from animals, foods of animal origin and
humans in India adds to the heterogeneity reports among Arcobacter species world-wide,
supporting diversity among same species. Close clustering between Arcobacters of
animal and human origin are indicative of probable zoonotic significance.
Description
THESES
Keywords
null