Phylogenetic analysis of isolates of respiratory tract infections in humans and sheep.

BACKGROUND

is an important opportunistic pathogen, which is capable of colonizing the respiratory system in both humans and animals causing mild to severe infections.

AIM

This study aims to isolate from the nasal discharges of human and sheep as well as identify the antibiotic resistance and molecular phylogeny of local isolates.

METHODS

A total of 100; 50 humans and 50 sheep, positive nasal swab isolates were selected, and confirmed biochemically and by the VITEK-2 system. Molecular testing using the polymerase chain reaction (PCR) and phylogeny was conducted.

RESULTS

On MacConkey agar, isolates appeared as large, pinkish, and mucoid colonies; while microscopically, it appeared as Gram-negative rods. Traditional biochemical tests revealed that 62% and 78% of human and sheep isolates were positive isolates, whereas respectively, 54.84% and 71.8% of these isolates were positive by VITEK-2. Antibiotic susceptibility tests showed that the human isolates were sensitive to aztreonam, piperacillin-tazobactam, ciprofloxacin, and cefuroxime. Subsequently, sheep isolates were sensitive to cefuroxime, ciprofloxacin, piperacillin-tazobactam, ampicillin, cefoxitin, and tetracycline. Targeting gene, a total of 17 human and 28 sheep isolates were molecularly positive . Phylogenetic analysis of study human and sheep isolates showed their identity to NCBI Indian (LC747146.1) and Iraqi (LC711141.1) isolates, respectively. Comparative analysis between the local human and sheep isolates revealed a significant identity that ranged from 99.82% to 99.88% with a percentage of mutation ranging from 0.008% to 0.002%.

CONCLUSION

is a highly prevalent bacterium in both human and sheep with an observable resistance to antibiotics. Molecular phylogeny of study isolates demonstrated their close relation, suggesting the possible direct or indirect transmission of the bacterium from sheep to human or . Moreover, studies are greatly important to estimate the routes of bacterial transmission. Also, extensive hygiene practices could be lowered the spreading of to farm workers.