Multiple antibiotic resistances among Shiga toxin producing Escherichia coli O157 in feces of dairy cattle farms in Eastern Cape of South Africa

Abstract

BackgroundShiga toxin–producing Escherichia coli (STEC) O157:H7 is a well-recognized cause of bloody diarrhea and hemolytic-uremic syndrome (HUS). The ability of STEC strains to cause human disease is due to the production of Shiga toxins. The objectives of this study were to determinate the prevalence, serotypes, antibiotic susceptibility patterns and the genetic capability for Shiga toxin production in Escherichia coli (STEC) strains isolated from dairy cattle farms in two rural communities in the Eastern Cape Province of South Africa. MethodsFecal samples were collected between March and May 2014, from individual cattle (n = 400) in two commercial dairy farms having 800 and 120 cattle each.Three hundred presumptive isolates obtained were subjected to polymerase chain reactions (PCR) for identification of O157 serogroup and Shiga toxin producing genes (stx1, stx2) on genomic DNA extracted by boiling method. Susceptibility of the isolates to 17 antibiotics was carried out in vitro by the standardized agar disc-diffusion method. Results Based on direct PCR detection, 95 (31.7 %) isolates were identified as O157 serogroup. The genetic repertoire for Shiga toxin production was present in 84 (88.42 %) isolates distributed as stx1 (37), stx2 (38) and stx1/2 (9) respectively while 11 of the isolates did not harbor Shiga toxin producing genes. Multiple antibiotic resistances were observed among the isolates and genetic profiling of resistance genes identified blaampC 90 %, blaCMY 70 %, blaCTX-M 65 %, blaTEM 27 % and tetA 70 % and strA 80 % genes among the antimicrobial resistance determinants examined.ConclusionWe conclude that dairy cattle farms in the Eastern Cape Province are potential reservoirs of antibiotic resistance determinants in the province.

Macrolide, glycopeptide resistance and virulence genes in Enterococcus species isolates from dairy cattle

“…Genetic profiling of the strA gene revealed that 50.88 % of the isolates harboured the resistance gene. The findings in this study are very similar to those of our previous study on virulence and antimicrobial resistance profiles of enterococcal isolates from pig farms within the same study area (Iweriebor et al, 2015b). Diarra et al (2010) also reported the prevalence of high antimicrobial resistance among enterococcal isolates from broiler chickens in Canada.…”

“…Antibiotic-resistant Enterococcus isolates from animal production have been reported (Aslam et al, 2012;Iweriebor et al, 2015a, b;Iwu et al, 2015; Jackson et al, 2007;Simjee et al, 2006). The resistance levels observed among our enterococcal isolates were higher than those reported in a Slovakian study on 82 isolates (Brtkova & Bujdakova, 2009).…”

“…In farm animals, the use of antibiotics that are critically important in human medicine could result in the emergence of new forms of multi-resistant bacteria that infect people. Some new strains of multi-resistant foodborne bacteria, such as Campylobacter, Salmonella and Escherichia coli that produce the ESBL and/or AmpC enzymes that inactivate nearly all beta-lactam antibiotics and the critically important 3rd and 4th generation cephalosporins, have been isolated from meat and faecal samples of farm animals (Dierikx et al, 2012;Iweriebor et al,. 2015b).…”

“…In our study, the prevalence of E. faecium was 52.9 % while the other species (E. durans, E. hirae, E. casseliflavus and E. faecalis) were lower in their occurrence. Enterococci from faecal samples of cattle can spread to humans through direct contact with animals, B. C. Iweriebor, L. C. Obi and A. I. Okoh through manure, through the use of manure for crop production, through milk or dairy products and also through faecal contamination of water via agricultural runoff into water bodies.Antibiotic-resistant Enterococcus isolates from animal production have been reported (Aslam et al, 2012;Iweriebor et al, 2015a, b;Iwu et al, 2015; Jackson et al, 2007;Simjee et al, 2006). The resistance levels observed among our enterococcal isolates were higher than those reported in a Slovakian study on 82 isolates (Brtkova & Bujdakova, 2009).…”

Characterization of Escherichia coli and other Enterobacteriaceae in producer-distributor bulk milk

“…One such E. coli pathotype which has been reported in milk outbreaks is the STEC which is a causative agent of haemorrhagic colitis and haemolytic uremic syndrome (HUS) (Oliver et al, 2009). The main route of infection with STEC in humans is via consumption of contaminated foods including milk, which is commonly associated with asymptomatic dairy cattle reservoirs (Iweriebor et al, 2015). Important STEC virulence encoding genes, which make E. coli an insidious threat to food safety, are the phage-encoded shigatoxin genes (stx1 and stx2) which inhibit protein synthesis of host cells and leads to cell death and intimin (eae) which mediate colonization.…”