1.Aeromonas: A New Emerging Pathogen Isolated from Water and Foods Khalifa Sifaw Ghenghesh Dept. of Microbiology and Immunology Faculty of Medicine, Tripoli University, Tripoli - Libya

2. INTRODUCTION Gram-negative, oxidase-positive, facultative anaerobic, rod-shaped bacteria. Almost all strains grow on MacConkey agar and some are lactosepositive. Habitat: Natural watersClinical Infections: Bacteremia: Particularly in the immunocompromised. Wound infections: exposure to water Gastroenteritis: Controversial ? Epidemiological evidence Some strains are causes of diarrhea Others 3. Virulence Factors: Exotoxins Invasiveness Adherence Others Antibiotic Resistance: - -lactams 4. Taxonomy Last edition of Bergy's Manual: 17 hybridization groups (HG) or genospecies (Based on DNA-DNA reassociation) and 14 phenospecies placed in the family Aeromonadaceae. A. caviae, A. hydrophila and A. veronii bv. sobria A. trota Sources: Water Foods 5. Hybridization groups (genospecies) and phenospecies of Aeromonas and their isolation from different sources in developing countries. Hybridization Genospecies groups (HG)PhenospeciesIsolation from:aClinical specimens Food Water ------------------------------------------------------------------------------------------------------------------------------------------------1 A. hydrophila A. hydrophila C C C 2 A. bestiarum A. hydrophila-like NR R NR 3 A. salmonicida* A. salmonicida NR C NR 3 Unnamed A. hydrophila-like NR NR NR 4 A. caviae A. caviae C C C 5A A. media A. caviae-like NR NR NR 5B A. media A. media R R R 6 A. eucrenophila A. eucrenophila NR R R 7 A. sobria A. sobria NR NR NR 8X A. veronii A. sobria NR NR NR 8Y A. veronii A. veronii.biovar sobria C C C 9 A. jandaei A. jandaei R NR NR 10 A. veronii A. veronii biovar veronii R NR NR 11 Unnamed Aeromonas sp. NR NR NR 12 A. schubertii A. schubertii R NR NR 13 Unnamed A. schubertii-like NR NR NR 14 A. trota A. trota R R R 15 A. allosaccharophila NR NR NR 16 A. encheleia NR R NR 17 A. popoffii NR NR NR -----------------------------------------------------------------------------------------------------------------------------------------------a C=common, R=rare, and NR=not reported. 6. Prevalence of Aeromonas sp. in diarrheic and non diarrheic children in some developing countries Country%positive /no examined DiarrheicP valueDominant speciesNon diarrheic---------------------------------------------------------------------------------------------------------------Bangladesh 9.2/814 3.0/814