Prevalence of CTX-M types among ESBL-producing pathogenic Escherichia coli isolates from foodborne diarrheal patients in Gyeonggi-do, South Korea.

Prevalence and characteristics of extended-spectrum ß-lactamase (ESBL)-producing pathogenic Escherichia coli from foodborne diarrheal patients were studied. Analysis of 495 E. coli isolates revealed that 80 isolates were ESBL-producing pathogenic E. coli, and enteroaggregative E. coli and enterotoxigenic E. coli were two of the most prevalent pathotypes. In silico Clermont phylo-typing of the 80 ESBL-producing E. coli showed that phylogroup A (49/80) and D (22/80) were the predominant phylogroups. The average nucleotide identity analysis of ESBL-producing E. coli disclosed that they could be grouped into two phylogenetic groups; 25 A and 55 B groups. All strains, except one, harbored the blaCTX-M gene. All CTX-M-15 type ESBL-producing strains also carried qnrS, a plasmid-mediated quinolone resistance gene (PMQR). These results suggest that the diversity of ESBL-producing E. coli is high and that co-existence of blaCTX-M-15 and qnrS genes is widespread, highlighting their high risk of antibiotic-resistance spreading in infectious disease outbreaks. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-024-01549-5.

The synergistic effect of herbal medicine and probiotics in pediatric functional constipation: A systematic review and meta-analysis.

BACKGROUND: Pediatric functional constipation (PFC) is a prevalent and persistent gastrointestinal disorder, that requires various treatments, including alternative approaches. This review assessed the synergistic efficacy of herbal medicine (HM) and probiotics for PFC. METHODS: We conducted a comprehensive search of 11 databases, including English, Chinese, and Korean databases, until June 29, 2023. The inclusion criteria were randomized clinical trials (RCTs) comparing the intervention of HM with probiotics to that of the same probiotics. Statistical analyses included calculation of the mean difference (MD), standardized MD, risk ratio (RR) with a 95% confidence interval (CI), and assessment of risk of bias using Review Manager Version 5.4 software. The Grading of Recommendations Assessment, Development, and Evaluation rating system was used to evaluate evidence quality. Potential publication bias was assessed using funnel plots, Egger test, the fail-safe N test, and Duval and Tweedie trim and fill method. RESULTS: A total of 22 RCTs involving 2228 patients were included in the meta-analysis. The HM and probiotics group exhibited superior outcomes compared to the probiotics alone group in various parameters: total effective rate (RR: 1.24, 95% CI: 1.19-1.29, P < .001), Bristol fecal Score (MD: 0.80, 95% CI: 0.71-0.89, P < .001), gastrointestinal peptide hormone (motilin) (MD: 35.37, 95% CI: 24.64-64.10, P < .001), inflammation indicator (nitrous oxide) (MD: -12.45, 95% CI: -15.12 to -9.77, P < .001), minimal sensitive volume of the rectum (MD: -8.7, 95% CI: -10.91 to -6.49, P < .001), and recurrence rate (RR: 0.30, 95% CI: 0.21-0.43, P < .001). CONCLUSION: The combination of HM and probiotics may exhibit a synergistic effect on PFC. Nevertheless, it is imperative to undertake rigorously planned RCTs to comprehensively evaluate the synergistic efficacy of HM and probiotics.

Discovery and characterization of a new genotype of Salmonella enterica serovar Bareilly isolated from diarrhea patients of food-borne outbreaks.

Since the first food-borne outbreak of Salmonella enterica serovar Bareilly in the UK (2010), it has been recognized as a new type of food-borne pathogen in S. enterica. To detect and characterize this new serovar pathogen in South Korea, a total of 175 Salmonella strains was isolated and 31 isolates were identified as S. Bareilly from various food-borne outbreaks between 2014 and 2018. While pulsed-field gel electrophoresis (PFGE) analysis using XbaI revealed two major groups (A and B) each with two subgroups (A1, A2/B1, B2), average nucleotide identity (ANI), single nucleotide polymorphism (SNP), and in silico multilocus sequence typing (MLST) analyses confirmed only two major groups. Interestingly, extended SNP analysis with 67 S. Bareilly strains from outbreaks in other countries revealed that A group strains between 2014 and 2016 shared a close evolutionary relationship with the strains from outside of South Korea; however, the B group strains in 2018 were located in a separate SNP tree branch. These findings suggest that the A group may share common ancestor with the strains of previous outbreaks in the UK or other countries, while the B group is a new genotype. Comparative virulence factor (VF) analysis between the A and B group strains showed that S. Bareilly in the B group has more various than that of the A group. A comparative biofilm formation assay supports for this, which B group strain GG-21 has higher biofilm formation activity than A group strain GG-07. Antibiotic susceptibility test of 31 S. Bareilly strains revealed high susceptibility to 17 tested antibiotics, suggesting that S. Bareilly can be easily treated by antibiotics.

Presence of plasmid-mediated quinolone resistance (PMQR) genes in non-typhoidal Salmonella strains with reduced susceptibility to fluoroquinolones isolated from human salmonellosis in Gyeonggi-do, South Korea from 2016 to 2019.

Non-typhoidal salmonellosis remains a pressing public health problem worldwide. Quinolones, particularly fluoroquinolones, are widely used to treat various infections, including non-typhoidal salmonellosis, which can be a serious illness. The emergence of fluoroquinolone-resistant Salmonella has resulted in treatment failure and high mortality rates. In this study, we estimated the presence of plasmid-mediated quinolone resistance (PMQR) genes in Salmonella enterica isolated from human salmonellosis patients in South Korea from 2016 to 2019. We evaluated the association of these genes with fluoroquinolone susceptibility. Antimicrobial susceptibility tests for Salmonella isolates were performed using the Vitek II system, and the minimum inhibitory concentrations (MIC) of ciprofloxacin and levofloxacin were determined using the E-test method. Plasmid-mediated quinolone resistance (PMQR) genes were detected by PCR amplification and quinolone resistance-determining regions (QRDRs) of the gyrA and parC genes were analyzed following Sanger sequencing of the PCR products. Thirty-four Salmonella strains with reduced susceptibility to fluoroquinolones (ciprofloxacin MIC ≥ 0.125 µg/mL and levofloxacin MIC ≥ 0.25 µg/mL) were selected from 208 human clinical Salmonella isolates. Among them, 22 Salmonella strains harbored one PMQR gene (qnrA, qnrB, or qnrS), and three Salmonella strains carried two PMQR genes (qnrS and aac(6')-Ib-cr or qnrA and qnrB). qnrS was the most common PMQR gene. Serotyping revealed that Salmonella 4,[5]12:i:- (32.4%, 11/34) and Salmonella Typhimurium (29.4%, 10/34) were the two most predominant serovars, and Multi-locus sequence typing (MLST) showed that ST19 and ST34 were the most frequent sequence types. In conclusion, qnr gene-positive Salmonella 4,[5],12:i:- and Salmonella Typhimurium were the main serovars responsible for reduced susceptibility to fluoroquinolones. Therefore, our findings suggest that PMQR-positive Salmonella strains, which can be isolated from various samples including human, food, and the environment, should be carefully monitored.

Development of a novel vector system for programmed cell lysis in Escherichia coli.

Although widely used as a host for recombinant protein production, Escherichia coli is unsuitable for massive screening of recombinant clones, owing to its poor secretion of proteins. A vector system containing T4 holin and T7 lysozyme genes under the control of the ptsG promoter derivative that is inducible in the absence of glucose was developed for programmed cell lysis of E. coli. Because E. coli harboring the vector grows well in the presence of glucose, but is lysed upon glucose exhaustion, the activity of the foreign gene expressed in E. coli can be monitored easily without an additional step for cell disruption after the foreign gene is expressed sufficiently with an appropriate concentration of glucose. The effectiveness of the vector was demonstrated by efficient screening of the amylase gene from a Bacillus subtilis genomic library. This vector system is expected to provide a more efficient and economic screening ofbioactive products from DNA libraries in large quantities.