Study on isolation, molecular detection of virulence gene and antibiotic sensitivity pattern of Escherichia coli isolated from milk and milk products

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%), icecream (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. [Vet World 2013; 6(8.000): 541-545

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“…Studies conducted on milk have revealed current findings are in disagreement with some other previous studies who have reported higher frequency of stx2 than stx1 31 . Studies conducted on bulk milk samples revealed 91% stx2, 8% stx1 and 41% of both stx1 and stx2 genes 4 .…”

Molecular Detection of Enterotoxigenic E. coli in Milk and Milk Products

“…Lower results were mentioned by Kumar and Prasad (2010) who found that the highest contamination was recorded in milk from vendors (26%) followed by dairy farm (20%). In addition, lower results were reported by Bali et al, (2013) (32.5%), Rashid et al, (2013) (33.96%), Virpari et al, (2013) High incidences of E. coli in the examined raw milk samples indicated neglected sanitary control in handling of milk and possibly fecal contamination. Microorganisms may gain entry into raw milk from the dairy animals experiencing subclinical or clinical mastitis, or from fecal contamination, particularly around the teats, and from the farm environment particularly the water source and utensils used for the storage of milk on the farm or during transportation (Ombarak and Elbagory, 2015).…”

Incidence of some pathogenic microorganisms in bulk tank milk in some farms of Gharbia governorate

“…Colifrom counts of raw bulk tank milk should be routinely performed to identify the hygienic status under which milk is produced and handled and sanitary status of udder and milking machines (Boor et al, 1998). Results in Table (2) showed the incidence of E. coli in the samples comprising of BTM was (12.5%), (25%) and (12.5%), higher incidence of E. coli (52%) was observed by Virpari et al (2013) and in Soomro et al (2002) 57%, while nearly similar results (26.4%) was reported by Bandyopadhyay et al (2011) and (30.2%) by Farzan et al (2012) lower incidence rate 2.4% was reported by Jayarao et al (2006).…”