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Research
(Published online : 01-06-2013)
19. Study on isolation, molecular detection of
virulence gene and antibiotic sensitivity pattern of Escherichia coli isolated
from milk and milk products -
P. K. Virpari, J. B. Nayak, M. N.
Brahmbhatt and H. C. Thaker
Vet World. 2013; 6(8): 541-545
doi:
10.5455/vetworld.2013.541-545
Abstract
Aim: The study was undertaken to isolate pathogenic E. coli from milk and
various milk products, detection of virulence gene using Polymerase chain
reaction (PCR) and investigate their antibiotic sensitivity pattern.
Materials and Methods: Altogether 250 milk and various milk products samples
consisting of raw milk (50), cheese (50), ice-cream (50), mawa (50) and dahi
(50) were collected from milk vendors, retail shops located in Anand city, under
aseptic precautions. For the enrichment of the organism from the collected
samples, MacConkey broth was used and inoculation was carried out on MacConkey
agar and EMB agar. Later on, to confirm the isolates, various biochemical tests
such as IMViC test, Urease test were performed. Evaluation of antibiotic
sensitivity pattern of E. coli was assessed by disk diffusion method. Finally
the E. coli isolates were screened for the presence of virulence associated
genes by PCR.
Results: The prevalence of E. coli was observed 32 % in the
samples comprising of milk (52.00%), cheese (28.00%), ice-cream (20.00%), mawa
(44.00%), and dahi (16.00%). Antibiotic sensitivity was recorded high for Co-trimoxazole
(100%) followed by Gentamicin (96.73%), Trimithoprime (93.47%) and Doxycycline
hydochloride (92.39%). Least sensitivity was recorded for Ampicillin (8.69%). In
this study, out of 80 E. coli isolates, 25 isolates (31.25%) were positive for
stx genes, of which 7 (8.75%) isolates were positive for stx1 gene only, while
12 (15.00%) isolates were positive for stx2 gene only and 5 (6.25%) isolates
were positive for both stx1 and stx2, 7 isolates (8.75%) were positive for eaeA
gene and all the isolate were negetive for rfb O157 gene. Conclusions:
Current study supports the finding that raw milk and various milk products can
be regarded as critical source of pathogenic E. coli This explains the need of
strict monitoring and surveillance for effective measures of hygiene and
sanitary practice during production of milk and various milk products.
Keywords: antibiotic sensitivity test, enteropathogenic E. coli, milk, milk
products, PCR
