Background: Riemerella anatipestifer (R. anatipestifer) is a gram negative, microaerophilic, non-motile, bipolar bacteria. High genetic diversity and molecular differentiation were reported among field isolates. Although the bacterium causes one of the most economically important duck diseases in the north-eastern region of India, little work has been done on isolation, identification and molecular characterization of the bacteria. Hence, the present investigation was undertaken with a view to characterize the R. anatipestifer isolates from ducks of Assam. Methods: Phenotypic and molecular identification of R. anatipestifer isolates from domesticated ducks of Assam, India were carried out during the period from February, 2019 to January 2020. A total of 624 samples (Ocular swab, throat swab, liver, spleen, kidney, brain, heart, lung) from ducks comprising of apparently healthy, ailing and dead ducks were collected from five districts of Assam, India were processed to isolate and identify the bacteria. The tentative identification of the bacteria was done based on phenotypic characteristics viz., colony morphology, growth characteristics and biochemical reactions. All the phenotypically positive isolates were further subjected to molecular identification based on PCR assay targeting 16S rRNA gene and ERIC sequence. Result: The bacteria could be isolated from different field samples. The highest percentage of the samples that yielded the bacteria are from brain (76%) followed by spleen (74%) of dead ducks and less number of ocular swab (33%) from apparently healthy ducks were found positive. Sequencing of the amplified product of the selected R. anatipestifer isolates targeting 16S rRNA gene revealed homology percentage of 96.5-100%. Further, sequences representing five geographical locations were submitted to NCBI gene bank. Phylogenetic studies of the isolates indicated that there is prevalence of at least two genetically different strains of R. anatipestifer in the study area. The study suggested that the R. anatipestifer infection is endemic in Assam causing varying rate of morbidity (39%) and mortality (53%) and molecular based confirmation is necessary besides phenotypic identification.

Methicillin resistant Staphylococcus aureus (MRSA) is highly divergent antibiotic resistant bacteria earmarked as “High” in global pathogens’ priority list varying the severity and resistance geographically. Here, MRSA were screened using mecA gene with Cefoxitin and other 27 antibiotics of 19 classes using disc diffusion method from a highly humid climate of India. Multiple Antibiotic Resistance (MAR) index was calculated. Minimum Inhibitory Concentration (MIC) was determined against 11 classes of antibiotics. Detection of major virulence genes tst-1 and lukPV were done. A total of 95.24% Hospital Associated (HA)-MRSA, 56.14% Community Associated (CA)-MRSA and 82.53 % Livestock Associated (LA)-MRSA were detected. Cefoxitin, Oxacillin, Ciprofloxacin, Fusidic acid and Ticarcillin-Clavulinic acid resistance was observed in more than 60% of HA-MRSA, CA-MRSA and LA-MRSA. Across the hosts, Mupirocin, Gentamicin, Linezolid, Co-trimoxazole, and Rifampicin were found effective. Vancomycin Intermediate Staphylococcus aureus (VISA) detected in CA-MRSA & LA-MRSA. Multidrug Resistant (MDR) was found very high but extensively drug-resistant (XDR) was detected moderately. No pan drug-resistant (PDR) was detected. Virulence gene tst-1 and lukPV were detected in 7.69% and 32.69% MRSA isolates. The gene tst-1 is reported for the first time in pre and post-caesarian samples from Gynaecology department in this region with high MDR. This study showed S. aureus and subsequent prevalence of MRSA is higher in this region then national data. 2nd generation Cephalosporins were found effective which is very encouraging due to their limited uses. Detection of tst-1 in caesarian samples is a serious threat as neonatal transmission of MRSA from mother is reported.

CSF is enzootic in most of pig-producing states, particularly in the NorthEastern (NE) region of India. In this study, a total of 249 sera and 190 tissue samples were collected from different parts of Meghalaya. Samples were processed by ELISA and RT-PCR for serological and molecular diagnosis. Representative positive samples from the Khasi Hills region were selected for sequencing and “close grid” phylogenetic relationship using partial genomic regions of 5′UTR and E2. High seroprevalence (74.7%) of CSFV was recorded. Detection of the CSFV genome in serologically positive serum samples and tissue samples was 61.29% and 18.94%, respectively. BLAST and phylogenetic analyses indicate the clustering of all the field samples in subgroup 2.2, with high identity with EF014334 from China. Molecular structural modelling of the E2 partial sequence using representative sequences MG563797 from Meghalaya and EF014334 from China indicate potential changes in the protein motif and its conformation, which may explain the emergence of subgroup 2.2 CSFV replacing the predominant subgroup 1.1 viruses in NorthEast India. The epidemiological information presented in this study may be helpful for determination of disease incidence in this region, whereas the virus profile may be useful for framing disease control programs.

Swine pasteurellosis, caused by Pasteurella multocida capsular types A and D, causes heavy economic loss to the pig farmers. The vaccine presently used is abacterin of Pasteurella multocida capsular type B that is proven to be effective against bovine pasteurellosis. However, its efficacy against swine pasteurellosis is questionable. The present study was carried out to evaluate the efficacy of calcium phosphate nanoparticle adjuvanted bivalent subunit vaccine prepared from Pasteurella multocida capsular types A and D along with a monovalent subunit vaccine prepared from Pasteurella multocida capsular type B in mice. The Alum precipitated bacterin vaccine was used as the control. The bivalent subunit vaccine comprising the immune components of both the capsular types showed significantly higher IgG response than either of the other two vaccines. Both the calcium phosphate nanoparticle adjuvanted vaccines could elicit 100% protection in mice against homologous challenges but the aluminum hydroxide adjuvanted bacterin vaccine could not elicit significant protection. Based on this preliminary work, it was concluded that the bivalent subunit vaccine would be a better option for immunization of swine against swine pasteurellosis. IMPORTANCE OF THE WORK: The swine pasteurellosis is an important economic disease affecting the pig population in the North-eastern part of India that contributes the major pig population. The disease is caused by Serotype A and D of Pasteurella multocida . At present the inactivated vaccine is used that is actually developed against P ₅₂ strain of serotype B:2 of Pasteurella multocida , which is mainly involved in haemorrhagic septicaemia (or bovine pasteurellosis) that affects the cattle, buffaloe, sheep and goat. As a result, the present vaccine does not give sufficient protection in pigs but gives significant protection in cattle, buffaloe, sheep and goat. Hence, there is a need of development of vaccine that can address specifically swine pasteurellosis by targeting serotype A and D of Pasteurella multocida .