Pathogenic potential of Aeromonas hydrophila isolated from surface waters in Kolkata, India.
ABSTRACT Members of the genus Aeromonas (family Aeromonadaceae) are medically important, Gram-negative, rod-shaped micro-organisms and are ubiquitous in aquatic environments. Aeromonas species are increasingly recognized as enteric pathogens; they possess several virulence factors associated with human disease, and represent a serious public health concern. In the present study, putative virulence traits of Aeromonas hydrophila isolates collected from different natural surface waters of Kolkata, India, were compared with a group of clinical isolates from the same geographical area using tissue culture and PCR assays. Enteropathogenic potential was investigated in the mouse model. Of the 21 environmental isolates tested, the majority showed cytotoxicity to HeLa cells (81 %), haemolysin production (71 %) and serum resistance properties (90 %), and they all exhibited multi-drug resistance. Some of the isolates induced fluid accumulation (FA ratio>or=100), damage to the gut and an inflammatory reaction in the mouse intestine; these effects were comparable to those of clinical strains of A. hydrophila and toxigenic Vibrio cholerae. Interestingly, two of the isolates evoked a cell vacuolation effect in HeLa cells, and were also able to induce FA. These findings demonstrate the presence of potentially pathogenic and multi-drug-resistant A. hydrophila in the surface waters, thereby indicating a significant risk to public health. Continuous monitoring of surface waters is important to identify potential water-borne pathogens and to reduce the health risk caused by the genus Aeromonas.
- Indian pediatrics 10/2013; 50(10):969-70. · 1.01 Impact Factor
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ABSTRACT: High incidence of mortality in carps was noticed in a polyculture fish farm situated in Orissa, India during March 2009 accounting for cumulative mortality of nearly 2% per day. The infected fish revealed gross ulcerative lesions on skin with erosion of scales and fin-and tail-rot. Acute tubular and diffused interstitial necrosis was observed in kidney tissue along with increased melanomacrophage reactions on histopathological examination. Hepatic and muscular necrosis was also noticed in most of the fish examined. The bacteria isolated from kidney, liver and blood samples were identified as Aeromonas hydrophila after biochemical characterization. This isolate was found to possess aerolysin, lipase, extracellular haemolysin and β-haemolysin genes contributing to its virulence. It was found sensitive to antibiotics amikacin, aztreonam, ceftazidime, ceftazidime, cefuroxime, cephotaxime, ciprofloxacin, co-trimoxazole, gentamicin, levofloxacin, nalidixic acid, netillin, nitrofurantoin, ofloxacin, streptomycin, tetracycline, tobramycin and trimethoprim. Experimental infection of Labeo rohita with this isolate resulted in similar clinical signs as those of collected from the farm. The LD50 dose was calculated to be 1.15 × 10 6 CFU/fish. This study suggests that A. hydrophila still remains an important bacterial pathogen from aquaculture point of view and regular examination of cultured fish is required to resist unexpected loss.Journal of Aquaculture. 07/2014; 16:27-37.
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ABSTRACT: The present study is designed to evaluate the in vitro and in vivo bactericidal and immunomodulating activities of hesperidin (HES) and ellagic acid (EA) against Aeromonas hydrophila. A hydrophila, an uncommon human pathogen, can cause invasive infections in immunocompromised individuals and common clinical presentations in acute gastrointestinal illness, soft-tissue infections and sepsis. The antimicrobial activities of medicinal plants against Aeromonas hydrophila have received only a cursory attention. We examined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values in vitro. Moreover, the effects of HES and EA against bacterial colonization were studied in vivo. Also, humoral immune response was tested against A. hydrophila-LPS or A. hydrophila-ECP antigen preparations and the intestinal histopathological alterations were studied. Data revealed that the treatments with HES and EA each had antimicrobial activities against A. hydrophila. Both HES and EA treatments significantly increased anti-LPS IgM levels and reduced anti-LPS and anti-ECP IgA levels to their normal values in comparison to the infected group, which recorded significantly elevated levels two weeks' post-infection. In conclusion, the present data suggest that HES and EA have antimicrobial and immunomodulating activities against murine A. hydrophila infections. Significant These data warrant clinical studies to delineate HES and EA roles in human infectious diseases.Life sciences 09/2013; · 2.56 Impact Factor