Molecular identification of bacterial flora of the nasal cavity of healthy caws

This study aimed to carry out the moleculer identification of aerobic bacterial nasal flora of clinically healthy calves, collected by nasal swabs, by using 16S rRNA sequence analysis.Nasal swab samples from 56 calves on 15 farms were used in the study, isolation of bacteria was carried out by using classical conventional methods, after examining the macroscopic and microscopic morphology of the factors, their identifications were carried out by using universal primers duplicating polymerase chain reaction of 16S rRNA gene. With the sequence analysis of the isolated 192 micro-organisms, it was determined that 143 (74.5%) were Gram-positive (Aerococcus sp., Arthrobacter sp., Bacillus sp., Brevibacillus sp., Brevibacterium sp., Corynebacterium sp., Enterococcus sp., Exiguobacterium sp., Micrococcus sp., Staphylococcus sp.) and 49 (25.5%) were Gram-negative (Acinetobacter sp., Citrobacter sp., Comamonas sp., Escherichia sp., Gamma sp., Klebsiella sp., Kluyvera sp., Mannheimia sp., Neisseria sp., Pantoea sp., Pasteurella sp., Proteus sp., Pseudomonas sp., Raoultella sp., Salmonella sp. ve Serretia sp.). Coagulase-negative staphylococci (36.5%), Bacillus sp. (15.6%), S. aureus (11.0%), M. haemolytica (6.3%), Enterobacteriaceae sp. (6.8%), P. multocida (5.2%), M. luteus (4.2%), Streptococcus sp. (2.6%), Acinetobacter sp. (2.6%), Pseudomonas sp. (2.1%), Corynebacterium sp. (1.0%) were the most commonly identified species.In our study, results of classical conventional methods microbial and molecular identification techniques were found to be similar. It was suggested that works related with molecular identification of nasal bacterial flora of the calves with respiratory system problems in the field should be conducted and, comparison of microorganisms bacterial species located in healthy and unhealthy flora should be carried out, and virulence and antibiotic resistance genes of the most common agents isolated from both flora should be determined at the future studies.