الفهرس 
Contents
Physiology of Cronobacter speciesOnly 14 pages are availabe for public view
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Abstract
C. sakazakiiis opportunistic pathogen associated with fatal neonatal infections, including meningitis, septicemia, sepsis and necrotizing enterocolitis (NEC), in addition, the mortality rates associated with Cronobacter infection have been broadly reported from 40 to 80% in infants . Beside the infant’s infection, the infections also occur in older children and adults and it cause serious infections as septicemia, pneumonia, osteomyelitis, wound infection and splenic abscess.
C. sakazakii is recognized worldwide as emerging foodborne pathogens. It could be isolated from a wide variety of food as cereal foods, fruits and vegetables. It also detected in food from animal origin as milk and milk products like cheese, dried milk, infant formula and ice cream. The contamination of the products caused by poor raw materials used and poor handling during manufacture processing, packaging and storage.
Therefore, this study was planned to determine the incidence of C. sakazakii in milk and some milk products in El-Minia City through conventional methodsincluding culture and biochemical identification.
C. sakazakii is the best known and the most important in terms of global impact on human disease, thus further identification including PCR, and antibiotic sensitivity to the various antibiotics used for its eradication.
A total number of 400 milk and some milk products were collected from different localities in El-Minia City including raw milk (150) which was collected from dairy shops (50) and farmer’s houses (50) as well as cheese (100) including (50) kareish and (50) domiati, milk powder (50), ice-cream(50) and yougurt (50) which were collected from dairy shops, farmer’s houses, street vendors and ice-cream shops. These samples were examined for the incidence of C. sakazakii using selective media: BrillianceEnterobactersakazakii agar.
The present study revealed that C. sakazakii were isolated in a percentage of (24%) from farmer’s houses, (14%) from dairy shops, (28%) from kareish, (16%) from domiati, (22%) from milk powder, (12%) from ice-cream and (6%) from yogurt. It could not be isolated from pasteurized milk samples.
Some biochemical tests was done .C. sakazakii was positive for catalase, nitrate reduction, inulin fermentation, esculin hydrolysis and citrate utilization.While it was negative for oxidase, urease and H2S production.
To confirm the identity of the subtype of the isolatedC. sakazakii, RT-PCR targetingompA gene was carried out followed by melting curve analysis. All suspected colonies produced positive amplification signals with melting peaks at Tm 79.2± 0.05◦Cwhich is consistent with the identity of the C.sakazakii.
The sensitivity of C. sakazakii to 13 antibiotics including amoxicillin (10µg), imipenem (10µg), norfloxacin (10µg), gentamycin (15µg), tetracyclin (30µg), cefotaxime (30µg), vancomycin (30µg) and cephalothin (20µg), clindamycin (2µg), ampicillin (10µg), cefuroxime (30µg), erythromycin (15µg) and chloramphenicol (30µg) was done. It is clearly observed that the highest sensitivity (100%) was for imipenem, norfloxacin, gentamycin, cefotaxime. On the other hand, high resistance was observed for vancomycin and clindamycin (100%), cephalothin(93.4%), erythromycin (87%) and cefuroxime (73.7%).
Potassiumsorbate is a permissible chemical preservative according to the regulations issued by the Egyptian Ministry of Health, FDA, FAO and WHO.The antimicrobial effect of potassiumsorbate (0.1, 0.2%) on the growth and viability of C. sakazakii in sterilized milk kept at room and refrigerator temperature was studied. It was noticed that there was a marked reduction in C. sakazakii number and extension in the shelf life up to 12th and 9th days upon adding 0.2 and 0.1% potassium sorbate, respectively at refrigerator temperature.Therefore potassium sorbate is necessary to ensure the safety of milk and milk products together with excellent sanitation conditions and proper storage.
Finally, the antimicrobial action of Hibiscus, β-glucan and lactoferrinagainst C. sakazakii was determined by agar well diffusion method. Results revealed that hibiscus and β-glucan had a bactericidal effect while,lactoferrin had the dual actions (bactericidal and bacteriostatic).