Prevalence of Aeromonas in different clinical and water samples with special reference to gastroenteritis.

ABSTRACT

A hospital based study was carried out in the Department of Microbiology, Tribhuvan University Teaching Hospital, Institute of Medicine with the aim to initiate the isolation and identification of Aeromonas spp. from the stool samples of gastroenteritic patients and to determine the prevalence of Aeromonas spp. in other clinical samples and water. Altogether 293 samples were investigated that include 172 stool samples, 60 pus/wound swabs, 20 body fluids and 41 water samples. The samples were collected and processed by standard microbiological techniques in order to isolate Aeromonas. Ampicillin blood agar (20 microg/ml) was used as selective medium for the isolation of Aeromonas. The specimen prevalence rate of Aeromonas spp. in stool was found to be 5.2% and the A. hydrophila (55.5%) was the predominant species followed by A. caviae (33.3%) and A. sobria (11.1%) in the stool samples. Likewise, 3.3% of pus sample showed positive growth of A. hydrophila. Aeromonas was not detected in any of the body fluids. Aeromonas spp. were isolated from 58.5% of water samples obtained from different hospitals. The commonest species was A. hydrophila (62.5%) followed by A. caviae (20.8%) and A. sobria (16.7%). In vitro susceptibility testing showed that the aminoglycosides and fluroquinolones were the effective antibiotics against Aeromonas. It was found that 88.9% of Aeromonas spp. isolated from stool samples were sensitive to gentamicin, 77.8% to ciprofloxacin, norfloxacin, tetracycline and ceftriaxone and 66.6% to nalidixic acid whereas cent percent Aeromonas spp. from water samples were sensitive to gentamicin, ciprofloxacin, norfloxacin, tetracycline and ceftriaxone and 75.0% to nalidixic acid. The enteric Aeromonas isolates were more resistant to antimicrobial agents than the water isolates.