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Review Article Aeromonas-Associated Infections in Developing Countries
Khalifa Sifaw Ghenghesh,1 Salwa F. Ahmed,2 Rania Abdel El-Khalek,2 Atef Al-Gendy,2 John Klena.2
1 2

Dept. of Microbiology and Immunology, Faculty of Medicine, Al-Fateh University, Tripoli, Libya. Dept. of Molecular Epidemiology, Clinical Trails and Military Service, NAMRU#3, Cairo, Egypt.

Abstract
Although their rolein gastroenteritis is controversial, Aeromonas species are recognized as etiological agents of a wide spectrum of diseases in man and animals. In developing countries, potentially pathogenic Aeromonas sp. are very common in drinking water and in different types of foods, particularly seafood. Several food-borne and water-borne outbreaks as well nosocomial outbreaks associated with aeromonads havebeen reported. Significant association of Aeromonas sp. with diarrhoea in children has been reported from several countries. These organisms are important causes of skin and soft-tissue infections and aspiration pneumonia following contact with water and after floods. High incidence of antimicrobial resistance, including to third-generation cephalosporins and the fluoroquinolones, is found amongAeromonas sp. isolated from clinical sources in some developing countries in Asia. Isolating and identifying Aeromonas sp. to genus level is simple and requires resources that are available in most microbiology laboratories for processing common enteric bacteria. The present review will cover the epidemiology, clinical syndromes, low-cost diagnostic methods, and antimicrobial resistance andtreatment of Aeromonas infections in developing countries. Key Words: Aeromonas, Developing countries, Diarrhea, Extraintestinal infections, Laboratory diagnosis, Antibiotic resistance. J Infect Developing Countries 2008; 2(2):81-98.
Received 7 December 2007 - Accepted 6 February 2008. Copyright © 2007 Ghenghesh et al. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction Although their role in gastroenteritis is controversial, Aeromonas species are recognized as etiological agents of a wide spectrum of diseases in man and animals [1]. The literature has indicated that some motile Aeromonas sp. are emerging food- andwater-pathogens of increasing importance [2]. These organisms have been associated with several food-borne outbreaks [3,4] and are increasingly being isolated from patients with traveler's diarrhoea [5,6]. Since 1980, more than 2,000 studies and more than 10 reviews on Aeromonas sp. have been reported in the English literature and the large majority of these reports were from developed countries. Todate no reviews are published on these organisms in developing countries. The present review will cover the epidemiology, clinical syndromes, low-cost diagnostic methods and antimicrobial resistance and treatment of Aeromonas infections in developing countries.

Taxonomy and Serology Until 1984, only four species of Aeromonas were known and these are A. hydrophila, A. caviae, A. sobria (presentname A. veronii biovar sobria) and A. salmonicida [7]. The latter is a nonmotile fish pathogen and rarely reported from clinical sources [8,9]. Since then the genus Aeromonas has evolved with the addition of new species and the reclassification of existing taxa. Previously Aeromonas sp. were placed together with Vibrio sp. and Plesiomonas shigelloides in the family Vibrionaceae. However, geneticstudies provided enough evidence to support the placement of aeromonads in a family of their own, Aeromonadaceae [10]. In the last edition of Bergy's Manual [11], 17 hybridization groups (HG) or genospecies and 14 phenospecies are described (Table 1). Assignment of hybridization groups is based on DNA-DNA reassociation techniques. While much of the confusion surrounding the taxonomy of the genus...