Isolation and molecular characterization of pathogenic Escherichia coli strains, their antimicrobial susceptibility Patterns and associated risk factors in diarrheic calves and Children at wolaita sodo town, southern ethiopia

Abstract

Pathogenic E. coli strains cause diarrheal infection in both calves and children due to their virulence factors.Their distribution is not well studied in Ethiopia, especially in current study area. Therefore, a cross sectional study was conducted from October 2017 to June 2018, with aim to isolate, molecularly detect pathogenic E. coli strains, to determine their antimicrobial susceptibility patterns and associated risk factors in diarrheic calves and children at Wolaita Sodo town. Purposive sampling technique was used to collect 88 feacal samples from diarrheic calves and 110 stool samples from diarrheic children. Semi-structured questionnaire, conventional culture, biochemical and molecular methods were conducted to achieve the objectives. Antimicrobial susceptibility patterns of the isolates were tested using the KirbyBauer disc diffusion method. All of the data were analysed using logistic regression in SPSS vertion 20. The overall isolation rate of E. coli in calves was 64.8% (57/88) (95% CI: 53.9- 74.7%). The occurrence of the bacterium differed significantly by age and colostrum feeding time (P<0.05). The odds of being infected was highest in calves aged below two weeks (OR 4.3; 95% CI 34.8- 56.4%; P=0.001). The overall isolation rate of E. coli in children was 61.8% (68/110) (95% CI: 52.1-70.9%). The occurrence of the bacterium differed significantly by age, contact with either animals or manure, negligence to hand washing before meal and exclusive breast feeding in six month (P<0.05). The odds of being infected was highest in children whose caretakers had habit of negligence to hand washing before meal (OR 6; 95% CI 30.8- 49.8%; P=0.01). For eleven drugs, E. coli isolates were resistant to (62.5%, 61.9%), intermidiately resistant to (3.5%, 9.4%) and susceptible to (34%, 28.7%) in calves and children, respectively. The overall virulent genes detected in calves and children was 77.2% (44/57) (95% CI 53.9-74.7%); and 55.9% (38/68) (95% CI 52.1%-70.9%), respectively. Among these stx1 [8 (14%), 6 (8.8%)] stx2, [5 (8.8%), 4 (5.9%)], eaeA [8 (14%), 5 (7.4%)], eaat [6 (10.5%), 14 (20.5%)] and St [5 (8.8%), 4 (5.9%)] were detected from calves and children, respectively. The MDR for E. coli isolates and their strains was 34 (59.7%) and 31 (70.5%), respectively in calves and 43 (63.2%) and 38 (100%) respectively in children.The MDR index value of DEC pathotypes was greater than or equal to 0.4 which indicates the high risk of resistance.The study demonstrated important pathogenic E. coli strains; and multi-drug resistance mostly in isolates containing more than one virulent gene. Wise use of antimicrobials and improving the hygienic practices in the farms and amongst parents of children reduces its occurrence.Therefore, awareness on importance of exclusive breast feeding to parents of children and colostrums feeding time for calves to farm owners should be maximized. Appropriate usage of antimicrobial agents should also be highly practiced among farms and hospitals