The current research involved the investigation of the prevalence and laboratory patterns of Aeromonas hydrophila in human clinical samples. Two hundred clinical samples were examined of which 20 samples (10%) were positive to the A. hydrophila and 180 samples (90) were negative. The highest isolation rate was detected in stool samples of 15 positive isolates (15%), which showed gastrointestinal infections to have a strong association. The rates of lower isolation were found in urine samples (7%), and blood samples (6.7%). Wound/burn samples did not recover any isolates which implies that this pathogen does not play a major role in this type of infection among the population under study.
The first classification was carried out on morphological basis. On both MacConkey agar and blood agar, all isolates grew well as non-lactose-fermenting colonies and gave smooth and hemolytic colonies respectively. The capability of growing in enriched media was indicated by the growth on chocolate agar. The microscopic observation revealed all the isolates to be Gram-negative bacteria.
Anoxidase- and catalase-tests showed that all the isolates were positive, as expected of A. hydrophila. The system was identified by VITEK 2 Compact system with 100 percent consensus with the conventional methods. PCR showed the presence of the lipase gene in 90% and the protease gene in 100% of isolates, indicating the genetic presence of virulence-associated determinants. In general, the research confirms the clinical value of A. hydrophila, especially in gastrointestinal infections, and the importance of a combination of the conventional, automated, and molecular diagnostic methods.