ABSTRACT
Background: Bovine tuberculosis (bTB) is a major bacterial disease that causes significant economic disruption across the globe. Aims: Our study was based on using a fluorescence polarization assay (FPA) that used fluorescein-labeled ESAT-6 protein to detect Mycobacterium bovis antibodies in bovine serum. Methods: The ESAT-6 protein was used in a FPA. Positive TB reactors were determined by the comparative intradermal test (CID) and interferon gamma test (IFN-γ). Antibodies against M. bovis were detected using a fluorescein isothiocyanate (FITC) labeled tracer and a whole culture FITC labeled tracer in the positive cattle. Results: Of the 192 animals tested for bTB, 37 were found to be positive by either the CID or IFN-γ assays. Using the mP values from five culture-positive serum samples, a cutoff value of more than >127 mp provided the best discrimination between positive reactors and negative bTB animals. The ESAT-6 results of FPA in comparison with CID results revealed sensitivity of 92.9% and specificity of 64.6%, and in comparison with results IFN-γ, showed sensitivity of 95.7% and specificity of 49%. FPA using FITC labelled ESAT-6 as a tracer has better sensitivity (95.7%) and specificity (49.1%) than IFN-γ test in humoral immune response in animals. Conclusion: This work revealed that the ESAT-6 protein as an antigen can be used in diagnosing bTB using a practical and sensitive humoral test.
ABSTRACT
BACKGROUND: Paratuberculosis and tuberculosis (TB) caused by Mycobacterium avium paratuberculosis (MAP) and Mycobacterium tuberculosis complex (MTC), respectively are economically important, chronic debilitating diseases affecting the dairy herds and are also potential zoonotic threats. AIMS: Differential diagnosis of paratuberculosis and TB in blood samples of cattle and buffaloes. METHODS: In this study, an in-house developed multiplex polymerase chain reaction (PCR) targeting MAP, Mycobacterium bovis and Mycobacterium smegmatis was used in blood samples (buffy coat) parallel with IS900 PCR and esxB PCR for diagnosis of paratuberculosis and TB, respectively; in a total of 202 cattle and buffaloes. RESULTS: Out of 202 animals, 12 (5.9%) and 17 (8.4%) animals were positive for MAP by multiplex PCR and IS900 PCR, respectively; from which only 8 (4%) animals were positive by both tests; whereas 4 and 9 animals were exclusively positive by multiplex PCR and IS900 PCR, respectively. None of the animals were found to be positive for M. bovis and M. smegmatis by the multiplex PCR. However, the esxB PCR detected 13 (6.4%) animals positive for TB. In fact, 3 (1.5%) animals were found to be co-infected by both paratuberculosis and TB. CONCLUSION: The in-house multiplex PCR detected MAP in buffy coat and there was a fair degree of agreement between the multiplex PCR and IS900 PCR in detection of MAP DNA though the latter detected more number of animals to be positive for MAP. Besides, esxB PCR showed a high diagnostic potential and can be used for diagnosis of TB from blood.
ABSTRACT
Antimicrobial drug use and overuse have been a topic of interest for many years, lately focusing on the growing resistance worldwide. This study was conducted in a small Indian hospital, where more than 80% of all admitted patients received antimicrobial drugs. Penicillin, gentamycin, co-trimoxazole, ciprofloxacin and metronidazole were most commonly used and all antimicrobial drugs were given empirically with no confirmation of the infective agent. Reports of increasing resistance to antimicrobial drugs in India, and elsewhere, necessitates a focus on how antimicrobials drugs are used in relation to investigations of resistance patterns among the local strains of pathogens. This study may be considered a base-line study, though of relevance for other hospitals, in particular in low-income areas, where development of resistance to standard antimicrobial drugs may have severe implications for both patients and health managers.