Molecular screening and risk factors of enterotoxigenic Escherichia coli and Salmonella spp. in diarrheic neonatal calves in Egypt
ABSTRACT The aim of the present study was to carry out molecular epidemiological investigation on enterotoxigenic Escherichia coli (ETEC) K99 and Salmonella spp. in diarrheic neonatal calves. Fecal samples were obtained from 220 diarrheic calves at 9 farms related to four governorates in central and northern Egypt. E. coli and Salmonella spp. isolates were examined for E. coli K99 and Salmonella spp. using PCR. ETEC K99 was recovered from 20 (10.36 %) out of 193 isolates, whereas Salmonella spp. was recovered from nine calves (4.09%). Multivariable logistic regression was used to evaluate the risk factors associated with both infections. ETEC K99 was significantly affected by age (P<0.01; OR: 1.812; CI 95%: 0.566-1.769), colostrum feeding practice (P<0.01; OR: 5.525; CI 95%: 2.025-15.076), rotavirus infection (P<0.001; OR: 2.220; CI 95%: 0.273-1.251), vaccination of pregnant dams with combined vaccine against rotavirus, coronavirus and E. coli (K99) (P<0.001; OR: 4.753; CI 95%: 2.124-10.641), and vitamin E and selenium administration to the pregnant dam (P<0.01; OR: 3.933; CI 95%: 0.703-1.248). Infection with Salmonella spp. was found to be significantly affected by the animal age (P<0.05; OR: 0.376; CI 95%: 0.511-1.369), Hygiene (P<0.05; OR: 0.628; CI 95%: 1.729-5.612), and region (P<0. 01; OR: 0.970; CI 95%: 0.841-1.624). The results of the present study indicate the importance of PCR as rapid, effective and reliable tool for screening of ETEC and Salmonella spp. when confronted with cases of undifferentiated calf diarrhea. Moreover, identification of the risk factors associated with the spreading of bacteria causing diarrhea may be helpful for construction of suitable methods for prevention and control.
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ABSTRACT: This prospective longitudinal study investigated the epidemiology of enteric disease associated with infections in calves aging up to 70 days. A total of 850 fecal samples were collected from 67 calves. Seventeen isolates of Salmonella spp. were recovered from feces of 11 calves (16.4 %), and statistical analysis revealed no association between the presence of Salmonella spp. and clinical signs of diarrhea or age. Virulence factors of Escherichia coli were identified in 103 strains: eae (7), K99/STa (7), Stx1 (7), Stx1/eae (36), Stx1/Stx2/eae (2), Stx2 (43), and Stx2/eae (1). There was statistical association between diarrheic animals carrying E. coli Stx1/eae+ in their feces at 2 and 4 weeks of age (P= 0.003) and E. coli Stx2+ at 5 weeks of age (P=0.03).Rotavirus was detected in 49 (5.76 %) fecal samples collected from 33 calves (49.2 %). The presence of rotavirus was correlated with diarrheic feces (P<0.0001) rather than feces with normal consistency. There was a significant relationship between age group and diarrhea (P=0.001). Bovine coronavirus (BCoV) was detected in 93 fecal samples collected from 46 calves (68.6 %). There was an association (P<0.0001) between diarrheic animals positive for BCoV and age groups. The results demonstrate the importance of the pathogens studied in the etiology of diarrhea in calves.Tropical Animal Health and Production 09/2014; 47(1). DOI:10.1007/s11250-014-0675-5 · 0.97 Impact Factor
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ABSTRACT: Salmonellosis is an important disease of cattle caused predominantly by Salmonella enterica serotypes Typhimurium (S. typhimurium) and Dublin (S. dublin). S. typhimurium causes acute enteritis and exudative diarrhea in calves. In addition to enteric disease, S. dublin can cause systemic infections, and may cause abortion in pregnant cows. Calves are considered a relevant model for non-typhoidal salmonellosis in humans. Experimental oral infections or inoculation of ligated ileal loops in calves have been extensively studied recently. This article reviews relevant published results regarding bovine salmonellosis as a natural disease or as an animal model.Research in Veterinary Science 04/2012; 93(1):1-6. DOI:10.1016/j.rvsc.2012.03.002 · 1.51 Impact Factor
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ABSTRACT: This study was conducted to determine the prevalence and characteristics of pathogenic Escherichia coli strains from diarrhoeic calves in Iran. A total of 156 E. coli isolates obtained from 180 diarrhoeic calves were evaluated with two multiplex PCR protocols for the detection of the K99, F41, Sta, Stx1, Stx2 and eaeA genes. Of these 156 isolates, 32 (20.5%) carried at least one virulent gene, 22 (14.1%) possessed enterotoxigenic E. coli (ETEC) virulent genes and 10 (6.4%) possessed shiga toxin genes, virulence factors of shiga toxin-producing E. coli (STEC). None of the isolates carried eaeA gene. All ETEC but one were isolated from 1- to 4-day-old calves (95.4%), and one was isolated from a 6-day-old calf. All STEC were isolated from 7- to 28-day-old calves. All ETEC carried both K99 and F41 fimbriae and possessed Sta enterotoxin gene.Comparative Clinical Pathology 05/2012; 22(3). DOI:10.1007/s00580-012-1442-5