The role of Enterotoxigenic Escherichia coli in the etiology of piglet diarrhea in Kayunga and Mityana Districts of Central Uganda

Abstract

Pig production in Uganda is highly constrained by rampant piglet mortalities with diarrhea being a key feature. The present study was conducted to determine possible involvement of Enterotoxigenic Escherichia coli as agents of diarrhea in piglets and elucidate the factors for the spread of diarrhea. Virulence factors were also determined that can be exploited to develop mitigation strategies in the smallholder pig value chains in Uganda. This was a cross-sectional study carried out from January to August 2020 on pre- and post-weaned piglets from households in Kayunga and Mityana districts of Central Uganda, selected by snowballing method due to lack of precise information on location of pig farmers in the study area. Data about herd management and risk factors for diarrhea were collected from selected farmers in the two districts. A total of 179 faecal samples were collected from randomly selected neonatal and pre-weaning piglets for bacteriological isolation of Escherichia coli. Multiplex polymerase chain reaction technique was used to detect the virulence (enterotoxin and fimbrial) genes from the isolates. From the 179 faecal samples, a total of 158 (88.3%) E. coli isolates were obtained. Virulence gene markers were detected in 18.4% (29/158) of the isolates. Among the investigated genes encoding for enterotoxin production, STb was the most prevalent (16/158, 10.13%), followed by STa (12/158, 7.59%), while gene for LT was not detected. The gene coding for F4 adhesin was the only one detected while F18 adhesin was not detected from the isolates. On multiple logistic regression analysis, only tertiary educational level (OR=0.141; 95% CI=0.30-0.666; p=0.013) and infrequent use of antibiotics (OR=0.231, 95% CI=0.062-0.859; p=0.029) among the farmers, were the two factors significantly protective of the piglets from diarrhea. The 158 E. coli isolates were tested for their susceptibility to eight antibiotics using agar disk diffusion test. Overall, 98.1, 65.2 and 41.8% of the isolates were resistant to erythromycin, tetracycline and ampicillin, respectively. However, gentamycin showed low resistance to all the strains tested (1.3%). The most effective drugs against E. coli were gentamycin, ciprofloxacin and kanamycin. These are the drugs of choice that should be prescribed for treatment of piglet diarrhea in Mityana and Kayinga districts.