Molecular detection and typing of methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci isolated from cattle, animal handlers, and their environment from Karnataka, Southern Province of India

Background and Aim: Methicillin-resistant staphylococci are among the emerging pathogens which have become a threat to both human and animal health. The present investigation intended to examine the occurrence and the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) recovered from cattle, its handlers, and their environment. Materials and Methods: A total of 666 specimens were subjected to culture method and genus-specific polymerase chain reaction (PCR) for the identification of Staphylococcus. Methicillin resistance was substantiated by PCR identification of mecA and mecC resistance determinants. Species-specific identification of mecA positive isolates was conducted by multiplex PCR. The unidentified species were deciphered by 16S rRNA gene sequencing approach. The mecA positive isolates were further characterized by staphylococcal cassette chromosome mec (SCCmec) typing and multilocus sequence typing (MLST). Results: Duplex PCR identified 728 Staphylococcus isolates, of which 66 (9%) were positive for mecA gene. MRSA constituted 24% of the total mecA positive isolates. Among MRCoNS, Staphylococcus epidermidis (42%), and Staphylococcus haemolyticus (11%) were the most common species identified. Overall, 47% of the mecA positive isolates belonged to SCCmec type V. MLST analysis showed eight different sequence types (STs) among MRSA isolates of which five were novel STs. Among methicillin-resistant S. epidermidis, 19 different STs were found, of which nine novel STs were detected. Conclusion: The increase in the prevalence of mecA positive staphylococci, especially MRCoNS in cattle is a great concern in view of their transmission potential. Hence, continuous monitoring and molecular characterization of methicillin-resistant staphylococci should be elucidated in human and animal sectors so as to prevent the spread of these resistant pathogens

Characterization of humoral and cellular immune responses elicited by reduced doses of Brucella abortus S19 (calfhood) vaccine in cattle calves of India

Brucella abortus S19 vaccine is a stable attenuated smooth strain, globally used as calfhood vaccine for the prevention of bovine brucellosis. Various agencies demonstrated different doses for vaccinating cattle and buffalo calves leading to ambiguity in selecting a suitable immune vaccine dose. The current study aimed at evaluating four graded doses of S19 vaccine to arrive at the dose which could produce comparable effectiveness as that of full dose prescribed by Indian Pharmacopeia among the Indian calves. Four vaccine doses of which the first dose consisted of full dose (40 × 109 CFU/dose) and the other three were 1/10th, 1/20th, 1/100th reduced doses along with control were tested. Each vaccine dose was administered to 13 cattle calves of 4–5 months of age maintained in separate groups. The blood samples were collected on 0 to 240 days post-vaccination (DPV) at the intervals of 0, 14, 28, 45, 60, 90, 150, 180 and 240 for assessment of vaccine-induced innate, humoral and cell-mediated immune responses. The sero-conversion of all vaccinated animals on DPV 45 and persistence of antibody till DPV 240 were noticed. No significant differences were observed in antibody response between animal groups that received full and 1/10th reduced doses. Innate and cell-mediated response by IL-6, TNF-α¸ IFN-γ, CD4+ and CD8+ cell counts showed dose-dependent responses with no significant difference between full dose and 1/10th reduced doses. The results suggest a possible one log reduction of full dose without compromising immune responses to aid larger vaccination coverage for creating herd immunity

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Not AvailableLateral flow assay (LFA) for brucellosis was standardized and evaluated. The test showed high diagnostic sensitivity, specificity and accuracy for diagnosis of brucellosis in bovines, small ruminants and swine. The study emphasized the importance of LFA as a useful, rapid, and easy-to-perform tool for the testing of brucellosis.Not Availabl