الفهرس 
Introduction
Descriptive information about P. shigelloidesOnly 14 pages are availabe for public view
 |  | from | 107 |  |  |
| | | from | 107 | | |
Abstract
P. shigelloides is a member of theEnterobacteriaceae family that gained a high interest. The organism has a worldwide distribution and could be isolated from mammals, marine mammals, fish, shellfish and crustaceans, reptiles and amphibians, birds, vegetables, milk and milk products. However, the aquatic environment is considered the primary reservoir of this organism.
It is an emerging cause of water and foodborne infections leading to gastrointestinal infections in human. Extra-intestinal infections due to P. shigelloides may occur, such as bacteremia, septicemia, meningitis, septic arthritis, pseudoappendicitis, cellulitis, etc. This microorganism has been implicated in a number of outbreaks of sporadic and epidemic gastroenteritis, particularly in tropical and subtropical countries. The rate of mortality by infection gets in over risk.
To our knowledge, this study is the first study that investigates the prevalence of P. shigelloides in Nile tilapia and surrounding environment in Assiut Citythrough conventional methods, including culture, biochemical and molecular identification techniques. Moreover, antibiotic sensitivity to the various antibiotics used for its eradication was tested.
A total number of 130 Nile tilapia fish (65 cultured fish and 65 wild fish samples) and 70 surrounding water samples were randomly collected from different localities in Assiut City as sale points, street vendors and Nile River. These samples were examined for the prevalence of P. shigelloides using different enteric media and selective media; IBB agar.
The present study revealed that P. shigelloides were isolated in a percentage of (6.15 %) from Nile tilapia (7.7% cultured and 4.6% wild) and (5.17%) from water samples.
Some biochemical tests were done. P. shigelloides was positive for oxidase, indol and catalase tests, while it was negative for H2S production, urease and citrate utilization tests.
Also, PCR was done on the isolated P. shigelloides targeting hugAgene. It was revealed that only twelve isolated P. shigelloides out of fifteen isolates which identified by biochemical method only were PCR positive.
Finally, the sensitivity of P. shigelloides to 17 antibiotics including ampicillin(10µg), amoxicillin+clavulanic acid(30µg),cefotaxime(30µg), ceftriaxone(30µg), imipenem(10µg), ceftazidime(30µg), gentamicin(10µg), tobramycin(10µg),amikacin(30µg), streptomycin(10µg), tetracycline(30µg),doxycycline(30µg), ciprofloxacin(5µg), ofloxacin(5µg),chloramphenicol(30µg), trimethoprim+sulfamethoxazole(25µg) was done.
Cefotaxime, ceftriaxone, ciprofloxacin, ofloxacin, chloramphenicol and trimethoprim+sulfamethoxazole were the best antibiotics, sensitivity for each was (100 %). while, lower sensitivity was shown by P. shigelloides for tetracycline and doxycycline which represented by 83.3 and 66.67%, respectively.
On the other hand, complete resistance was observed for ampicillin and amoxicillin+clavulanic acid and high resistance for erythromycin (91.61%).