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The present study was conducted to investigate the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli carrying other virulence genes associated with piglet diarrhoea. Faecal samples from the piglets with history of diarrhoea were processed for isolation of E. coli and were tested for their ability of ESBL production. ESBL encoding genes and other virulence genes were detected by specific PCR, and amplicons were sequenced. Ability of transferring the ESBL genes between the enteric bacteria was tested in in vitro HGT. A total of 170 E. coli was isolated, of which 43 (25.29 %) were confirmed as ESBL producer by double disc synergy test (DDST). Altogether, 6.47 and 2.94 % isolates were positive for bla TEM and bla CTX-M-15 genes, respectively, of which 2.35 % isolates were positive for both the genes and only 0.6 % isolate was positive for the bla CTX-M gene alone. The resistance traits could not be transferred to the recipient host. Based on PCR, 2 (1.18 %) and 1 (0.59 %) isolates were recorded as Shiga-toxin-producing E. coli (STEC) and enteropathogenic E. coli (EPEC), respectively. Both the STEC (one isolate positive for stx 2 and another positive for stx 2 and hlyA) isolates belonging to serogroup O2 and NT were also positive for the bla CTX-M-15 gene. This is the first report of ESBL-producing E. coli isolate possessing the STEC gene associated with piglet diarrhoea.

Aim:The present study was conducted to record the prevalence of extended spectrum β-lactamases (ESBLs) producing Escherichia coli, Salmonella spp., and Klebsiella pneumoniae from pig population of Assam and Meghalaya and to record the ability of the resistant bacteria to transfer the resistance genes horizontally.Materials and Methods:Fecal samples (n=228), collected from pigs of Assam (n=99) and Meghalaya (n=129), were processed for isolation and identification of E. coli and Salmonella spp. All the isolates were tested for ESBLs production by double disc synergy test (DDST) followed by screening for ESBLs producing genes (blaTEM, blaSHV, blaCTX-M, and blaCMY) by polymerase chain reaction (PCR). Possible transfer of resistance encoding genes between enteric bacterial species was carried out by in vitro and in vivo horizontal gene transfer (HGT) method.Results:A total of 897 enteric bacteria (867 E. coli and 30 Salmonella) were isolated and identified. Altogether 25.41% isolates were confirmed as ESBL producers by DDST method. Majority of the isolates were E. coli followed by Salmonella. By PCR, 9.03% isolates were found positive for at least one of the target resistance genes. blaSHV was absent in all the isolates. blaCMY was the most prevalent gene. All the E. coli isolates from Assam were negative for blaTEM. A total of 2.76% isolates were positive for blaTEM + blaCMY. On the other hand, 0.67% isolates were positive for blaCTX-M + blaCMY genes. Only 0.33% isolates carried all the three genes. Altogether, 4.68% bacteria carried the resistance encoding genes in their plasmids. blaTEM gene could be successfully transferred from Salmonella (donor) to E. coli (recipient) by in vitro (5.5-5.7×10−5) and in vivo (6.5×10−5 to 8.8×10−4) methods. In vivo method was more effective than in vitro in the transfer of resistance genes.Conclusion:The pig population of Assam and Meghalaya are carrying multidrug resistance and ESBLs producing E. coli and Salmonella. The isolates are also capable to transfer their resistance trait to other bacterial species by HGT. The present finding could be considered as a serious public health concern as similar trait can also be transmitted to the human commensal bacteria as well as pathogens.

How to cite this article: Varte Z, Dutta TK, Roychoudhury P, Begum J and Chandra R (2014) Isolation, identification, characterization and antibiogram of Pasteurella multocida isolated from pigs in Mizoram with special reference to progressive atrophic rhinitis, Veterinary World 7(2): 95-99. Introductionfor induction of the experimental disease, development of improved diagnostics, development of effective Progressive atrophic rhinitis (PAR) is a widely therapeutic/ prophylactic pharmaceutical approaches prevalent, upper respiratory tract disease of swine and development of immunoprophylactic products for characterized by sneezing, snuffling, nasal discharge, effective control of the disease. epistaxis, growth retardation, reduction in feed There is paucity of information regarding PAR in utilization, degeneration and atrophy of the nasal pigs in India, particularly in North Eastern Region. turbinate bone leading to visible distortion and Therefore, the present study was conducted for shortening of the snout [1]. Moreover, it has been isolation and identification of P. multocida from nasal recognized as a contributor to debilitating and fatal cavities of pigs of Mizoram with or without clinical porcine pneumonia for at least 120 years and continues lesions of PAR followed by their detection, capsular to be sustained, unabated with high prevalence in typing and screening for toxA gene by PCR based different part of the world [2]. Toxigenic strains of P.assays. multocida (both capsular type A and D) alone, or pigs, 9 were showing respiratory distress as a suspected Amongst the livestock, pig is most important and case of atrophic rhinitis. Samples were collected from almost every family rears pig as backyard venture.local household pigs as well as from organized pig Since the pig rearing is an important sector in rural farms. economy in this region, a better understanding of PAR Detection of P. multocida by PCR assay: Each swab and its impact on animal husbandry and economy is was grown in Brain-Heart Infusion (BHI) broth essential. Studies on PAR should provide a foundation o overnight at 37 C. After incubation, 1 ml of bacterial suspension was centrifuged at 7084 g. The bacterial pellet was washed thrice with sterile normal saline solution (NSS) (0.85% w/v) and resuspended in 300 µl Materials and Methods:Four hundred nasal swabs sampled from pigs were collected from 6 different districts of Mizoram. Swabs were processed for detection and isolataion of P. multocida by PCR and traditional bacteriological assays. Isolates were subjected for multiplex PCR for capsular typing, detection of toxA gene and characterization by RAPD-PCR. Isolates were also tested for antimicrobial sensitivity profile by disc-diffusion method.Results: A total of 21 swabs were found to be positive by P. multocida species specific PCR (PM-PCR) with an amplicon of 460 bp, of which P. multocida could be isolated from 15 swabs (3.75%). All the isolates were grouped under capsular type A (n=9) and D (n=6) by multiplex PCR. All the isolates were ...

Classical swine fever is the most insidious and devastating disease of pigs and wild boars. The virus is closely related to the other members of the genus Pestivirus. The outbreak recorded in Mizoram, India was strategically important as the state shares porous international boundary with East Asian countries. Both immunodiagnostic and molecular techniques were used to confirm the involvement of Classical swine fever virus (CSFV) in this outbreak. Sandwich ELISA and direct FAT could detect CSFV in the tissue samples. RT-nPCR specifically amplified E2 and 5'NTR product of 271 bp. Phylogenetic analysis showed, that the Mizoram isolate (MZ4/69) was very close to the Chinese strain Shimen-HVRI (93.0%) rather than other Indian isolate . Present study provides a valuable sequence based molecular data on Indian isolate of CSFV and will be useful in investigation on transmission of such disease from neighbour countries.