Virulence and antimicrobial resistance genes of pathogenic Escherichia coli from piglets showing diarrhea before and after ban on antibiotic growth promoters in feed

Abstract: This study examined the prevalence of adherence factors, toxin genes, antimicrobial resistance phenotypes, and resistance genes in Escherichia coli (E. coli) isolated from piglets with diarrhea before and after the ban on antibiotic growth promoters (AGPs) in Korea from 2007 to 2018. In this period, pathogenic 474 E. coli isolates were obtained from diarrheic piglets. The virulence factors and antimicrobial resistance genes were assayed using a polymerase chain reaction, and the susceptibility to antibiotics was tested according to the Clinical and Laboratory Standards Institute guidelines. After the ban on AGPs, the frequency of F4 (12.5% to 32.7%) increased significantly, and LT (31.9% to 20.3%) and EAST-I (46.5% to 35.2%) decreased significantly. In addition, the resistance to streptomycin (45.8% to 67.9%), cephalothin (34.0% to 59.4%), and cefazlin (10.4% to 28.8%) increased significantly. Colistin resistance plasmid-mediated genes, mcr-1 and mcr-3, were detected after the ban on AGPs. The results of this study can provide useful data for analyzing the impact of the ban on AGPs on the virulence profiles and antimicrobial resistance of E. coli isolated from piglets with diarrhea in Korea.

Prevalence of O-serogroups, virulence genes, and F18 antigenic variants in Escherichia coli isolated from weaned piglets with diarrhea in Korea during 2008–2016

To diagnose colibacillosis, detection of O-serogroups and virulence genes has been recommended worldwide. The prevalence of virulence factors can fluctuate over time. The objectives of this study were to determine the prevalence of O-serogroups, virulence genes, and F18 subtypes among pathogenic Escherichia coli isolated from weaned piglets with diarrhea in Korea. Between 2008 and 2016, 362 E. coli were isolated from weaned piglets with diarrhea. Hemolysis was determined in blood agar, and O-serogroups were identified using the slide agglutination technique. The genes for the toxins and fimbriae were amplified by polymerase chain reaction (PCR). Real-time PCR was conducted to discriminate between F18 subtypes. Although the most prevalent serogroup was O149 (11.3%) in the last 9 years, O139 (19.1%) became the most prevalent in recent years (2015–2016). The most predominant pathotype was enterotoxigenic E. coli (61.3%). The frequencies of Shiga-like toxin-producing E. coli (STEC) (23.4%), O139 (19.1%), Stx2e (35.1%), and F18ab (48.7%) increased over the most recent years. Although enterotoxigenic E. coli was the most predominant pathotype, the frequencies of O139, Stx2e, STEC, and F18ab have increased in recent years. These results demonstrate that there have been temporal changes in the predominant O-serogroups and virulence genes over the last decade in Korea. These findings can be practicable for use in epidemiology and control measures for enteric colibacillosis in Korean piggeries.

Oral malodor-reducing effects by oral feeding of Weissella cibaria CMU in Beagle dogs

This study assessed the effects of Weissella cibaria (W. cibaria) CMU on oral health in male and female beagles (n = 18) by measuring oral malodor and periodontal disease-related parameters (calculus, plaque, and gingivitis indices). Oral malodor and indicators of periodontal disease were assessed in five treatment groups: negative control (scaling and 0.24 mg of maltodextrin, n = 3), positive control (0.24 mg of maltodextrin, n = 3), and W. cibaria CMU groups (each n = 4) at low (CMU-L, 2 × 10⁷ colony forming unit [CFU]), medium (CMU-M, 2 × 10⁸ CFU), and high (CMU-H, 2 × 10⁹ CFU) concentrations. After feeding with W. cibaria CMU for 6 weeks, total volatile sulfur compound concentrations in the CMU-L (2.0 ± 1.04 ng/10 mL), CMU-M (2.4 ± 1.05 ng/10 mL), and CMU-H (2.6 ± 1.33 ng/10 mL)groups were significantly lower than in the positive control group (3.2 ± 1.65 ng/10 mL). Also, CMU-L (1.4 ± 0.83 ng/10 mL) and CMU-H (1.9 ± 1.14 ng/10 mL) groups had methyl mercaptan levels lower than that in the positive control group (2.4 ± 1.21 ng/10 mL) at week 2. The plaque index was significantly lower in the CMU-H group (4.5 ± 0.28) than in the positive control group (5.9 ± 1.08) at week 6. W. cibaria CMU could be useful as a novel oral hygiene probiotics for reducing volatile sulfur compounds production and inhibiting plaque growth in companion animals.

Oral malodor-reducing effects by oral feeding of Weissella cibaria CMU in Beagle dogs / 대한수의학회지

This study assessed the effects of Weissella cibaria (W. cibaria) CMU on oral health in male and female beagles (n = 18) by measuring oral malodor and periodontal disease-related parameters (calculus, plaque, and gingivitis indices). Oral malodor and indicators of periodontal disease were assessed in five treatment groups: negative control (scaling and 0.24 mg of maltodextrin, n = 3), positive control (0.24 mg of maltodextrin, n = 3), and W. cibaria CMU groups (each n = 4) at low (CMU-L, 2 × 10⁷ colony forming unit [CFU]), medium (CMU-M, 2 × 10⁸ CFU), and high (CMU-H, 2 × 10⁹ CFU) concentrations. After feeding with W. cibaria CMU for 6 weeks, total volatile sulfur compound concentrations in the CMU-L (2.0 ± 1.04 ng/10 mL), CMU-M (2.4 ± 1.05 ng/10 mL), and CMU-H (2.6 ± 1.33 ng/10 mL)groups were significantly lower than in the positive control group (3.2 ± 1.65 ng/10 mL). Also, CMU-L (1.4 ± 0.83 ng/10 mL) and CMU-H (1.9 ± 1.14 ng/10 mL) groups had methyl mercaptan levels lower than that in the positive control group (2.4 ± 1.21 ng/10 mL) at week 2. The plaque index was significantly lower in the CMU-H group (4.5 ± 0.28) than in the positive control group (5.9 ± 1.08) at week 6. W. cibaria CMU could be useful as a novel oral hygiene probiotics for reducing volatile sulfur compounds production and inhibiting plaque growth in companion animals.