Detection of enterotoxin genes and antibiotic susceptibility pattern in Yersinia Enterocolitica isolated from cheese in Basrah

Abstract EN

One hundred fifty cheese samples were collected between 8 October 2017 to February 2018.

Fifty samples from each cows , buffalos and sheep.

The sample transferred to TSB (tryptone soy broth) and PBS (Phosphate buffer saline) for enrichment and cooled enrichment procedure respectively.

Using Yersinia selective agar TSB enrichment showed high percentage of suspected Yersinia isolation.

Eleven isolates from cow cheese (22%), 10 isolates from buffaloes cheese (20%) and 8 isolates from sheep cheese (12%).

In contrast PBS enrichment showed better selectivity to reduce bacterial number other than suspected Yersinia enterocolitica isolates.

The results indicate there were 8 isolates from cow cheese (22%), 9 isolates from buffaloes cheese (20%) and 7 isolates from sheep cheese (16 %).

The suspected colonies that grow on selective agar and having bull eye appearance were subjected to biochemical identification.

The results showed that cow and buffaloes cheese were contaminated with this bacterium at the percentage of 8% and 6% respectively.

Sheep cheese were also contaminated with Yersinia enterocolitica at the percentage of 4% .

The total percentage of isolation of Yersinia enterocolitica from all animals were 6.%..

The isolated strains were highly susceptible toward azithromycin, streptomycin, and Gentamycin, followed by Ciprofloxacin and Chloramphenicol (93.3%).

The low susceptibility were found toward vancomycin (6.66%) followed by Cloxacillin (33.3%).

The result of polymerase chain reaction (PCR) for enterotoxin genes, ystA and ystB were investigated by PCR using a pair of primers for each.

The results showed that ystA gene was absent in all nine investigated strains while ystB gene was present in four strain at a ratio 44.4%.