In this study, eight Escherichia coli isolates were obtained from milk samples of dairy cattle suffering from clinical/subclinical mastitis. Isolates were characterized for antimicrobial resistance traits and virulence genes. Results revealed that one isolate was harbouring New Delhi metallo-beta-lactamase gene (blaNDM ). Cloning and sequencing of the PCR amplicon confirmed the identity of the gene (GenBank accession no. KC769583) having 100% homology with blaNDM-5 (GenBank accession no. JN104597.1), and this isolate was susceptible to colistin, chloramphenicol and tetracycline only. Moreover, another isolate carried extended-spectrum beta-lactamase (ESBL) gene - blaCTX-M , and all isolates possessed blaTEM gene. Of the eight isolates, only one isolate was positive for shiga toxin gene (stx2), and none were harbouring stx1 gene. Occurrence of New Delhi metallo-beta-lactamase (blaNDM ) in one E. coli isolate and ESBL genes in other isolates poses a potential threat to human health following possible entry and spread through food chain.
Aim:The aim of this work was to detect antibiotic resistance in Gram-negative bacteria isolated from subclinical mastitis in cattle in West Bengal.Materials and Methods:The milk samples were collected from the cattle suffering with subclinical mastitis in West Bengal. The milk samples were inoculated into the nutrient broth and incubated at 37°C. On the next day, the growth was transferred into nutrient agar and MacConkey agar. All the pure cultures obtained from nutrient agar slant were subjected to Gram-staining and standard biochemical tests. All the bacterial isolates were tested in vitro for their sensitivity to different antibiotics commonly used in veterinary practices. All Gram-negative isolates including positive control were subjected to polymerase chain reaction (PCR) for detection of blaCTX-M, blaTEM, blaSHV, blaVIM, tetA, tetB, tetC, and tetM genes considered for extended-spectrum β-lactamase (ESBL), metallo-β-lactamase, and tetracycline resistance.Results:In total, 50 Gram-negative organisms (Escherichia coli, Proteus, Pseudomonas, Klebsiella, and Enterobacter) were isolated from milk samples of subclinical mastitis infected cattle. Among these Gram-negative isolates, 48% (24/50) were found either ESBL producing or tetracycline resistant. Out of total 50 Gram-negative isolates, blaCTX-M was detected in 18 (36%) isolates, and 6 (12%) harbored blaTEM genes in PCR. None of the isolates carried blaSHV genes. Further, in this study, 5 (10%) isolates harbored tet(A) gene, and 8 (16%) isolates carried tet(B) gene. No tet(C) gene was detected from the isolates.Conclusion:This study showed emerging trend of antibiotic-resistant Gram-negative bacteria associated with subclinical mastitis in cattle in West Bengal, India.
The clinico-pathological and therapeutic studies on a natural outbreak of psoroptic acariosis in 10 New Zealand White rabbits of either sex and aged between 1 to 2 years were carried out during the period from July to December 2003. The diagnosis was made on the basis of clinical signs and examination of skin scrapings. Clinical signs recorded were severe itching and crust formation on ears, forehead, face, eyelids, forelimbs and back. Level of Hb, TEC, lymphocyte count, total protein and albumin were significantly (p < 0.05) low while TLC, neutrophil and eosinophil counts were significantly (p < 0.05) high in affected rabbits. The disease was effectively controlled by ivermectin (Inj. Mectin®, Alembic) @ 200 µg per kg bwt given SC once in a week for 2 injections and lincomycin (Inj. Alincomycin® Vet., Alved) @ 20 mg per kg bwt given IM daily for 7 days for combating secondary bacterial infection. The complete clinical recovery and absence of mite in the skin scrapings on day 10 onwards of starting of therapy was recorded.Key words: Rabbit; Psoroptes cuniculi; haematological changes; ivermectindoi: 10.3329/bjvm.v2i2.2561Bangl. J. Vet. Med. (2004). 2 (2): 155-158
Emergence of antimicrobial resistance mediated through New Delhi metallo-β-lactamases (NDMs) is a serious therapeutic challenge. Till date, 16 different NDMs have been described. In this study, we report the molecular and structural characteristics of NDM-5 isolated from an Escherichia coli isolate (KOEC3) of bovine origin. Using PCR amplification, cloning and sequencing of full blaNDM gene, we identified the NDM type as NDM-5. Cloning of full gene in E. coli DH5α and subsequent assessment of antibiotic susceptibility of the transformed cells indicated possible role of native promoter in expression blaNDM-5. Translated amino acid sequence had two substitutions (Val88Leu and Met154Leu) compared to NDM-1. Theoretically deduced isoelectric pH of NDM-5 was 5.88 and instability index was 36.99, indicating a stable protein. From the amino acids sequence, a 3D model of the protein was computed. Analysis of the protein structure elucidated zinc coordination and also revealed a large binding cleft and flexible nature of the protein, which might be the reason for broad substrate range. Docking experiments revealed plausible binding poses for five carbapenem drugs in the vicinity of metal ions. In conclusion, results provided possible explanation for wide range of antibiotics catalyzed by NDM-5 and likely interaction modes with five carbapenem drugs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.