Reduction of Carriage of EnterohemorrhagicEscherichia coliO157:H7 in Cattle by Inoculation with Probiotic Bacteria

Abstract

Bacteria inhibitory to Escherichia coli O157:H7 were isolated from cattle and evaluated for their potential for reducing carriage of E. coli O157:H7 in calves. Eighteen of 1,200 bacterial isolates from cattle feces and intestinal tissue samples were screened and determined to inhibit the growth of E. coliO157:H7 in vitro. Seventeen of the isolates were E. coli and one was Proteus mirabilis. None produced Shiga toxin. Genomic DNA fingerprinting by pulsed-field gel electrophoresis revealed 13 distinguishable profiles among the 18 isolates. Two calves inoculated perorally with a mixture of all 18 isolates (1010 CFU) appeared to be normal and did not develop signs of clinical disease throughout a 25- to 27-day observation period. These bacteria colonized segments of the gastrointestinal tract and were in feces at the termination of the experiment (25 and 27 days postinoculation) at levels of 50 to 200 CFU/g. Fifteen cannulated calves were studied to determine the efficiency of the probiotic bacteria in reducing or eliminating the carriage of E. coli O157:H7. Nine calves served as controls, with each animal receiving perorally 1010 CFU ofE. coli O157:H7. E. coliO157:H7 was detected intermittently in the rumen samples from all control animals throughout 3 weeks postinoculation, whereasE. coli O157:H7 was shed at various levels in feces continuously throughout the experiment (mean, 28 days).E. coli O157:H7 was isolated from the rumens and colons of eight of nine and nine of nine calves, respectively, at the termination of the study. Six calves each received perorally 1010 CFU of probiotic bacteria and then 2 days later received 1010 CFU of E. coli O157:H7.E. coli O157:H7 was detected in the rumen for only 9 days postinoculation in two animals, for 16 days in one animal, for 17 days in two animals, and for 29 days in one animal. E. coli O157:H7 was detected in feces for only 11 days postinoculation in one animal, for 15 days in one animal, for 17 days in one animal, for 18 days in one animal, for 19 days in one animal, and for 29 days in one animal. At the end of the experiment (mean, 30 days), E. coli O157:H7 was not recovered from the rumen of any of the six animals treated with probiotic bacteria; however, E. coli O157:H7 was recovered from the feces of one of the animals. This animal was fasted twice postinoculation. These studies indicate that selected probiotic bacteria administered to cattle prior to exposure to E. coli O157:H7 can reduce the level of carriage ofE. coli O157:H7 in most animals.

Microcin MccPDI reduces the prevalence of susceptible Escherichia coli in neonatal calves

“…If so, the microcin-producing strain might be more effective as a prophylaxis to prevent the colonization of pathogenic strains. During initial studies that investigated the use of colicinogenic strains as probiotics to limit the colonization of EHEC, calves were pretreated with a mixture of probiotic strains and subsequently challenged with EHEC (Zhao et al 1998Tkalcic et al 2003) rather than coinoculating the competing strains. Another study gave calves daily doses of colicinogenic E. coli throughout the experiment (Schamberger et al 2004).…”

Natural antimicrobial peptides from bacteria: characteristics and potential applications to fight against antibiotic resistance

“…Different Gram-negative and Gram-positive bacteriocins are known to target pathogens, including Clostridium difficile and emerging antibiotic-resistant bacteria such as MRSA, VRE and entero-haemorrhagic E. coli (Zhao et al 1998;Piper et al 2009;Rea et al 2010c). Recent research has indeed shown that bacteriocin-based therapeutic approaches might be a part of the solution in the fight against pathogens.…”

The Role of Mucosal Microbiota in the Development, Maintenance, and Pathologies of the Mucosal Immune System

“…All 19 of these strains are nonproducers of Shiga toxin. Those selected probiotic bacteria, orally administered to cattle prior to exposure to E. coli O157:H7, can reduce the level of carriage of E. coli O157:H7 in most animals (Zhao et al, 1998). Another set of data suggests that L. salivarius 51R, which was isolated from chicken caeca and administered orally to newly hatched broiler chickens, can significantly lower counts of enterococci and coliforms in the crop during the whole experimental period (Rada and Rychly, 1995).…”