Study on molecular and virulence characterization of aeromonas species isolated from different sources
KrishiKosh
View Archive InfoField | Value | |
Title |
Study on molecular and virulence characterization of aeromonas species isolated from different sources
|
|
Creator |
Rather, Mudasir Ali
|
|
Contributor |
Wani, Shakeel Ahmed
|
|
Subject |
Aeromonas, Prevalence, Water, Fish, Raw Meats, Human Diarrhea, RFLP, RAPD-PCR, ERIC-PCR, Multiplex PCR, Sequencing, Haemolysis, Vasopermeabilty Reaction
|
|
Description |
The present study describes the prevalence and antibiogram of Aeromonads in foods of animal origin, water and human diarrheal samples. The molecular epidemiology and in-vitro and in-vivo virulence characterization of the isolated Aeromonas spp. was also studied. Of the 609 samples comprising, water (182), fish (172), chicken (57), mutton (83), beef (31) and human diarrheic stools (83) screened for the presence of Aeromonas spp., 155 (25.45%) were positive. The prevalence of Aeromonas spp. in water, fish, chicken, mutton, beef and human diarrheal samples was 26.37, 39.30, 14.03, 22.89, 19.35 and 7.23%, respectively. The isolates of Aeromonas from all sources were identified as A. hydrophila (23.87%), A. caviae (20.64%), A. veronii bv sobria (18.06%), A. salmonicida (8.39%), A. popoffii (6.45%), A. trota (5.16%), A. schubertii (3.87%), A. jandaei (2.58%) and A. allosaccharophila (2.58%). Thirteen isolates (8.39%) could be identified to genus level only. A polymerase chain reaction (PCR) used to confirm the Aeromonas genus detected 153 of 155 isolates identified as Aeromonas phenotypically. The speciation was studied by restriction fragment length polymorphism of PCR amplified segment of 16S rRNA gene and the expected fragments were generated. Analysis of restriction enzyme digestion pattern indicated that the fragments generated could be used to identify the species of Aeromonas barring few exceptions. Molecular characterization of virulence factors encompassed a multiplex PCR for detection of three enterotoxin genes (act, alt and ast) of Aeromonas isolates. The act, alt and ast genes were detected in 104 (67.09%), 98 (63.22%) and 11 (7.06%) of isolated Aeromonads, respectively. The gene patterns identified included; act/alt (47.09%), act (13.54%), alt (10.96%), act/alt/ast (5.16%) and act/ast (1.93%). All the isolates were haemolytic on rabbit blood agar plates while haemolytic activity was shown by 92.25% of the isolates on sheep blood agar. The in-vivo virulence characterization of isolates was studied by vascular permeability reaction in rabbit skin which were marked after 12 hr of intradermal injection and ranged between 7 and 19.6 mm in diameter. Strains having enterotoxin genes produced higher VPR zones compared with those not carrying the gene. The molecular epidemiology of isolates was attempted at two different levels by random amplification of polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus sequence PCR (ERICPCR). The RAPD-PCR did not yield enough amplification products; therefore, the genetic variability could not be studied by RAPD-PCR. The ERIC-PCR was however able to type all the isolates and most of the isolates from water were identical to one other and also to the isolates from fish. The two A. caviae isolates from human diarrheal samples were identical to A. caviae recovered from water, indicating water as the most important source of Aeromonas infection. A high degree of resistance was observed against ampicillin (97.42%), ampicillin/cloxacillin (89.03%), polymyxin B (87.74%), amoxycillin (72.90%), roxithromycin (70.32%), erythromycin (61.29%) and streptomycin (54.84%). The isolates were highly sensitive to enrofoxacin (96.77%), ciprofloxacin (94.19%), ofloxacin (92.9%), ceftraixone (90.32%), norfloxacin (85.81%), tetracycline (85.81%), gentamicin (84.52%) and doxycycline (83.23%). The sequence analysis of enterotoxin genes revealed a high similarity of the genes with sequences available in the GenBank. |
|
Date |
2016-08-22T13:52:35Z
2016-08-22T13:52:35Z 2013 |
|
Type |
Thesis
|
|
Identifier |
http://krishikosh.egranth.ac.in/handle/1/73294
|
|
Language |
en
|
|
Format |
application/pdf
|
|
Publisher |
SKUAST
|
|