Isolation and identification of Cronobacter species from some animal sources

Abstract

This work was carried out to study the bacteriological importance of Cronobacter sakazakiias a potential foodborne emerging pathogen involved in severe illness and deaths in humans, especially neonates due to consumption of contaminated infant powdered infant formula (PIF) (PIF milk and food). A total of 100 samples [PIF milk (n=55), PIF food (n=15), milk powder (n=15) and milk powder products (n=15) were collected and subjected to bacteriological examination for the presence of Cronobacter. Six samples out of 100 examined (6%) were found positive for Cronobacter spp. The isolation rates were 4% in PIF milk and 1% in PIF food. The identity of the isolated organism was confirmed as Cronobacter spp. by subjecting the bacteriologically positive samples to PCR technique using 16S rRNA species specific primers. Cronobacter specific 16S rRNA was detected respectively in 3/5 and 1/5 of bacteriologically positive PIF milk and PIF food examined. All positive 16S rRNA (n=4) were examined for the presence of C. sakazakii. C. sakazakiiwere confirmed in an isolate from 3 isolates of PIF milk and one of PIF food. The outer membrane protein A (ompA) gene was detected in 2 identified C. sakazakii isolates, while gene encoding for zinc-metaloprotease (zpx) was only identified in 3 C. sakazakii isolates. These results lead to the conclusion that examined milk products could be a potential source of C. Sakazakii, so the retailed powdered milk could have public health significance. Further studies are needed to study control strategies of C. sakazakii.

Isolation and Molecular identification of Cronobacter sakazakii isolated from different foodstuffs and infant stools

“…Five selected C. sakazakii isolates (one isolate from the examined samples of powdered milk infant formula, milk powder, minced meat, cow milk, and diarrheic infant stool) were tested for detection of Cronobacter 16S rRNA gene by using QIAamp® DNA Mini Kit instructions (Qiagen, Germany, GmbH), Emerald Amp GT PCR mastermix (Takara, Japan). PCR technique was done by the primer as shown in table (1) and running conditions: one cycle of denaturation at 94℃ for 5 min, followed by 35 cycles of 94℃ for 30 s, 52℃ for 40 s, and 72℃ for 1min. PCR was completed with a final extension at 72C for 10 min.…”