A study was carried out to find the different serotypes of E.coli isolates from the diarrhoeic calves in organized farms and in unorganized areas. One hundred and twenty nine isolates of E. coli were isolated from 250 diarrhoeic calves. All the isolates of E. coli were typed for ‘O’ antigen. Out of the one hundred and twenty nine isolates of E. coli serotyped, one hundred sixteen serotypes belonged to 22 different ‘O’ serogroups (O20, O22, O69, O11, O84, O147, O68, O107, O123, O153, O157, O1, O6, O17, O36, O51, O60, O92, O102, O140, O158 and O159), 8 isolates were untypable and 5 were rough. The highest percentage was found for O20 serotype (22.48%) followed by O22 (14.73%) and O69 (10.08%). Serotypes O20, O22, O69, O84, O107 and O123 were found in both organized farms as well as in unorganized areas.
Colibacillosis is a disease of young animals and neonates caused by Escherichia coli. It is known to be the most important neonatal disease which causes a major economic loss in livestock production (SaAyinzat et al., 2015). The most commonly found and well-studied pathogens for calf scours are enteropathogenic E. coli (EPEC) (Vagh and Jani, 2010). It is the major cause of calf scours, causing mortality between 5-25% (Basoglu, 1992) or even as high as 54.58% (Khan and Khan, 1997). Serotyping of E. coli occupies a central place in the history of this pathogen (Lior, 1996). Prior to the identification of specific virulence factors in diarrhoeagenic E. coli strains serotype analysis was the predominant means by which pathogen strains were differentiated. According to modified Kauffman scheme, E. coli is serotyped on the basis of their O (somatic), H (flagellar) and K (capsular) surface antigen profiles (Edwards and Ewing, 1972; Lior, 1996). Over 700 antigenic types or serotypes of E. coli have been recognized based on O, H, and K antigens. Serotyping is important in distinguishing the small number of strains that actually cause disease.
Materials and Methods
In the present study, 129 samples were collected from Ganderbal and Srinagar districts of Kashmir Valley. The Kashmir valley is located between the Karakoram and the Pir Panjal Range in the Indian state of Jammu and Kashmir. It has moderate climate, which is largely defined by its geographic location. Compared with other plain parts of India, Kashmir valley enjoys a more moderate climate but weather conditions are somewhat unpredictable.
Study was performed according to the ‘Guidelines for Animal Experimentation’ approved by the Institutional Animal Care Committee.
The samples were collected by sterilized swabs directly from rectum of the diarrhoeic calves below 3 months of age irrespective of sex and age for the isolation of E. coli reared under different managemental conditions i.e., a) organized farms which included, Cattle Research Station Manasbal and Military Dairy Farm, Qamarwari, Srinagar, b) unorganized areas/ selected areas of district Ganderbal and Srinagar which include local villages and c) Clinical complex, FVSc & AH, Shuhama.
The faecal swabs collected under sterile measures were inoculated in MacConkey’s broth/Nutrient broth and incubated at 37 0C for 24 hours. A loopful of inoculam from each tube showing gas production was streaked on MacConkey’s agar media plates and incubated at 37 0C for 24 hours. An isolated, smooth, glossy and translucent, centrally raised rose-pink colony was picked up and transferred on Eosin Methylene-blue (EMB) agar media and incubated in a similar manner. The characteristic smooth, raised and mucoid colony with typical “metallic sheen” was considered to be E. coli. One or two such colonies were stained by Gram’s Method and simultaneously transferred to nutrient agar slants for cultural and biochemical characteristics. The suspected E. coli isolates were sent to National Salmonella and E. Centre, Central Research Institute, Kasauli (Himachal Pradesh) for serotyping.
Results and Discussion
In the present study, 129 E. coli isolates with different ‘O’ serogroups were recorded in different locations viz., organized farms and unorganized areas. Out of 129 E. coli isolates, 116 isolates belonged to 22 different ‘O’ serogroups while 8 isolates were untypable and 5 were rough (Table 1).
Table 1: E. coli serotypes isolated from calves suffering from colibacillosis
|S. No.||O Serotypes||Frequency||%age|
Among the 116 ‘O’ serotypes the highest percentage of 22.48 was found for O20 serotype followed by O22 and O69 serotypes having percentage of 14.73 and 10.08 respectively. Serotypes O11 and O84 were having percentage of 6.98 each where as serotype O147 was having percentage of 3.88. Percentage of 2.33 was seen in serotypes O68, O107, O123, O153 and O157. Serotypes O1, O6, O17, O36, O51 and O60 were having percentage of 1.55 each. The lowest percentage of 0.78 was found for O92, O102, O140, O158 and O159. Eight isolates were untypable with percentage 6.20 and 5 were rough isolates having percentage of 3.88. Among the 129 isolates 55 were from organised farms and 74 were from un-organised areas. Serotypes O11,O17, O51, O68, O102, O140 and O147 were found in organised farms where as serotypes O1, O6, O36, O60, O92, O153, O157, O158 and O159 were found in un-organised areas where as serotypes O20, O22, O69, O84, O107 and O123 were found in both organized farms as well as in un-organised areas.
Most E. coli strains are harmless, but some serotypes are pathogenic and can cause serious enteritis in humans as well as in animals. The harmless strains are part of the normal flora of the gut, and can benefit their hosts by producing vitamin K2, and by preventing the establishment of pathogenic bacteria within the intestine. But some serotypes are associated with diarrhoea, hemorrhagic colitis, and hemolytic uremic syndrome in humans and animals. Serotyping is the foundation of the diagnosis of pathogenic E. coli (Lisa et al., 2005). The distribution of different serotypes of E. coli varies with geographical regions and their prevalence in man and animals in a particular area. A shift in ‘O’ serogroups along with their virulence factors has also been observed (Soderlind et al., 1988). The serogroups O157, O68, O36, O17 and O11 recorded in present study has also been reported earlier (Panda and Panda, 1987; Wani et al., 2004; Tripathi and Soni, 1984; Minakshi et al., 1992; Kaura et al., 1991). The serogroups O1, O20, O22, O153, O123, O60 and O102 recovered in this study has also been reported earlier in diarrhoeic and non- diarrhoeic calves (Joon and Kaura, 1993; Hussain et al., 2003; Wani et al., 2004). The serogroup O69 recovered in this study has also been reported by Aniruddha et al. (2009) from diarrhoeic calves. The serogroups O84, O147, O107, O6, O51, O92, O158 and O159 seems not to be documented in cattle or in calf.
Authors are thankful to the DRI, FVSc & AH Shuhama, SKUAST-K, J&K for providing necessary man power for sample collection and required lab facilities.