• Microbiology and Biotechnology Letters
• /
• v.17 no.1
• /
• pp.56-62
• /
• 1989

To find bacteria which can inhibit growth of enteropathogenic Clostridium perfringens ATCC 13124, spore forming butyric acid bacteria were isolated from 26 fecal samples of infants. Fourteen strains were found to be antagonistic to the enteropathogen and five of them produced butyric acid. A strain which produced the highest butyric acid was selected and identified as Clostridium butyricum. This organism sporulated in SM medium in 36 hours with optimum rates at 37$^{\circ}C$ and at pH 5.5. The spores tolerated well at high heat and acidity, and possible application of Clostridium butyricum as intestinal controller was discussed.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.9
• /
• pp.1191-1199
• /
• 2021

Enteropathogenic Escherichia coli (EPEC), which belongs to the attaching and effacing diarrheagenic E. coli strains, is a major causative agent of life-threatening diarrhea in infants in developing countries. Most EPEC isolates correspond to certain O serotypes; however, many strains are non-typeable. Two EPEC strains, EPEC001 and EPEC080, which could not be serotyped during routine detection, were isolated. In this study, we conducted an in-depth characterization of their putative O-antigen gene clusters (O-AGCs) and also performed constructed mutagenesis of the O-AGCs for functional analysis of O-antigen (OAg) synthesis. Sequence analysis revealed that the occurrence of O-AGCs in EPEC001 and E. coli O132 may be mediated by recombination between them, and EPEC080 and E. coli O2/O50 might acquire each O-AGC from uncommon ancestors. We also indicated that OAg-knockout bacteria were highly adhesive in vitro, except for the EPEC001 wzy derivative, whose adherent capability was less than that of its wild-type strain, providing direct evidence that OAg plays a key role in EPEC pathogenesis. Together, we identified two EPEC O serotypes in silico and experimentally, and we also studied the adherent capabilities of their OAgs, which highlighted the fundamental and pathogenic role of OAg in EPEC.

• Journal of Microbiology
• /
• v.44 no.2
• /
• pp.226-232
• /
• 2006

Swarming has proven to be a good in vitro model for bacterial surface adherence and colonization, and the swarming differentiation of a bacterium has been shown to be coupled with changes in the expression of virulence factors associated with its invasiveness, particularly in the early stages of infection. In this study, we attempted to determine whether the expression of vvhA, which encodes for hemolysin/cytolysin (VvhA), is either upregulated or downregulated during the swarming differentiation of V. vulnificus. The insertional inactivation of vvhA itself exerted no detectable effect on the expression of V. vulnificus swarming motility. However, in our lacZ-fused vvhA transcriptional reporter assay, vvhA expression decreased in swarming V. vulnificus as compared to non-swarming or planktonic V. vulnificus. The reduced expression of vvhA in swarming V. vulnificus increased as a result of the deletional inactivation of luxS, a gene associated with quorum sensing. These results show that vvhA expression in swarming V. vulnificus is downregulated via the activity of the LuxS quorum-sensing system, suggesting that VvhA performs no essential role in the invasiveness of V. vulnificus via the adherence to and colonization on the body surfaces required in the early stages of the infection. However, VvhA may playa significant role in the pathophysiological deterioration occurring after swarming V. vulnificus is differentiated into planktonic V. vulnificus.

• Journal of agricultural medicine and community health
• /
• v.30 no.2
• /
• pp.137-149
• /
• 2005

Objectives and Methods: This study was performed to investigate the etiologic bacterial, viral and protozoal organisms for the diarrhea from hospitals in Chungnam area from January to December in 2004. Total of 787 fecal samples were collected and examined. Results and Conclusions: In test for enteropathogenic bacteria, total of 79 cases out of 787 samples from hospitals showed positive isolation. Among 79 positive samples, 27 cases were confirmed as Salmonella spp.. 20 cases as pathogenic E. coli, 18 cases as Clostridium perfringens, 6 cases as Staphylococcus aureus, 4 cases as Shigella spp. and 4 cases as Vibrio parahaemolyticus. In test for enteropathogenic virus, 190 cases out of 787 samples from hospitals showed positive reaction. Among 190 samples, 115 cases were confirmed as rotavirus, 55 cases as norovirus, 5 case as astrovirus, 4 case as rotavirus & norovirus, 3 cases as adenovirus, 2 case as rotavirus & astrovirus. In test for enteropathogenic protozoa, 6 cases out of 787 samples from hospitals showed positive result. Among 6 samples, 5 cases were confirmed as Entamoeba histolytica and 1 cases as Giardia lamblia. When we classified the positive results by the age of the patients, the highest isolation rate was noted in a group of age under 10 and over 60 for bacterial, viral and protozoal pathogens. Especially, patient below age of 5 showed high positive rate. When we classified the positive results by the time, pageathogenic bacteria were isolated throughout the year, and the highest frequency was noted in August. On the other hand, pathogenic viruses were detected more frequently during the colder season from December to April. Antimicrobial susceptibility test for the isolated bacteria resulted as follows; Salmonella strains showed high drug resistance rates against ampicillin, chloramphenicol, tetracycline, nalidixic acid, ticarcillin. Shigella strains showed high drug resistance rates against ampicillin, trimethoprim/sulfamethoxazole, chloramphenicol, tetracycline, ampicillin/sulbactam, ticarcillin. Pathogenic E. coli strains showed high drug resistance rates against ampicillin, cephalothin, gentamicin, tetracycline, nalidixic acid, ampicillin/sulbactam, ticarcillin.

• Proceedings of the Korean Society of Veterinary Pathology Conference
• /
• 2003.10a
• /
• pp.33-33
• /
• 2003

There prevalence of $\beta$-lactamases bacteria in animals has been increased since 1990s [1]. The resistance in E coli which is mediated by $\beta$-lactamases hydrolyze the $\beta$-lactam ring eventually inactivate the antibiotics [2]. Generally, $\beta$-lactamases can be classified into four main groups and eight subgroups according to their functional and structural characteristics [3]. The detection of $\beta$-lactam antibiotic-resistant bacteria by DNA chip has been described [4]. The chip has a specific probe DNAs that contained the $\beta$-lactam antibiotic-resistant genes which was labeled by multiplex PCR reaction with a mixture of primer sets that were designed to amplify specific gene. Here we report the susceptibility of enteropathogenic E. coli isolated from pigs in Korea using the DNA chip in detecting $\beta$-lactam antibiotic-resistant genes. (omitted)

• Journal of Food Hygiene and Safety
• /
• v.4 no.2
• /
• pp.155-163
• /
• 1989

Three species of lactobacilli (L. casei, L. acidophilus, L. bulgaricus) were tested for their antibacterial activity. They all were antagonistic to growth of enteropathogenic Escherichia coli and Salmonella enteritidis in associative cultures in YS-medium (0.1 % yeast extract + skimmilk). Sal. enteritidis was more sensitive to the inhibition than was E. coli. Control cultures of E. coli and Sal. enteritidis were pH 5.08 and 5.70 in 72 hrs of incubation and the associative cultures were pH 3.35-4.48. The increases in pH resulting from growth of the lactobacilli in the associative cultures appeared to be sufficient and mainly responsible for the antagonistic actions exerted on the pathogens.

• Molecules and Cells
• /
• v.24 no.2
• /
• pp.294-300
• /
• 2007

The mammalian glycosylphosphatidylinositol (GPI) anchor consists of three mannoses attached to acylated GlcN-(acyl)PI to form $Man_3$-GlcN-(acyl)PI. The first of the three mannose groups is attached to an intermediate to generate Man-GlcN-(acyl)PI by the first mannosyltransferase (GPI-MT-I). Mammalian and protozoan GPI-MT-I have different substrate specificities. PIG-M encodes the mammalial GPI-MT-I which has 423 amino acids and multiple transmembrane domains. In this work we cloned PIG-M homologues from humans, Plasmodium falciparum (PfPIG-M), and Saccharomyces cerevisiae (GPI14), to test whether they could complement GPI-MT-I-deficient mammalian cells, since this biosynthetic step is likely to be a good target for selective screening of inhibitors against many pathogenic organisms. PfPIG-M partially restored cell surface expression of the GPI-anchored protein CD59 in PIG-M deficient mammalian cells, and first mannose transfer activity in vitro; however, this was not the case for GPI14.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.27 no.2
• /
• pp.95-103
• /
• 2024

Purpose: Diarrhea is one of the leading causes of mortality in children living in developing countries. The etiology of acute diarrhea in each healthcare center varies depending on place, time, and population. This study aimed to identify pathogen patterns in human immunodeficiency virus (HIV)-infected and non-HIV children suffering from acute diarrhea, using multiplex real time reverse transcriptase polymerase chain reaction (RT-PCR), in an Indonesian tertiary hospital. Methods: This cross-sectional study was conducted at Dr. Cipto Mangunkusumo National Hospital from March 2019 to April 2020. Results: The study showed that multiplex RT-PCR results were positive in 58.9% of the specimens, with more positive results in HIV-infected children than in non-HIV-infected children (70% vs. 54.7%). Altogether 72 enteropathogens were detected from all specimens. Enteropathogens in non-HIV children with acute diarrhea consisted of bacteria (70.6%) and viruses (29.4%) with a predominance of enteroaggregative Escherichia coli (25.4%), followed by Campylobacter spp. (11.8%), enteropathogenic E. coli (9.8%), Norovirus GII (7.8%), and Clostridium difficile (7.8%). Enteropathogens in HIV-infected children consisted of viruses (57.1%), bacteria (28.6%), and parasites (14.3%) comprising Norovirus GII (24%), Cryptosporidium spp. (14.3%), Campylobacter spp. (14.3%), Norovirus GI (14.3%), and Astrovirus (14.3%). Cryptosporidium spp. was the only parasite found in this study and was found only in HIV-infected children. In non-HIV children with acute diarrhea, most pathogens were invasive bacteria, while in HIV-infected children, more viral and parasite infections occurred, primarily caused by opportunistic pathogens. Conclusion: The pattern of enteropathogens can help clinicians determine further examinations and appropriate empirical antimicrobial therapy for the patient.

• The Journal of the Korean Society for Microbiology
• /
• v.22 no.1
• /
• pp.55-59
• /
• 1987

Salmonella typhi infection, which was the most frequent enteric infection in Korea, has been decreasing, while the infection of other serogroups of Salmonella has been increasing since the later part of 1970s. In 1986, the number of serogroup B isolated by us increased to 46, which corresponds 21.1% of all enteropathogenic bacteria isolated from stool specimens. Salmonella isolates resistant to antimicrobial agents were extremly rare in Korea, in the 1970s. However, 7 of 13 serogroup B isolates showed resistance to ampicillin or to chloramphenicol in 1984. Among the serogroup B isolates in 1986, 71.7% and 69.6% were resistant to ampicillin and to chloramphenicol respectively. The minimum inhibitory concentrations of ampicillin and chloramphenicol against these isolates were >$128\;{\mu}g/ml$ and $128\;{\mu}g/ml$ respectively.

• Fisheries and Aquatic Sciences
• /
• v.16 no.4
• /
• pp.221-227
• /
• 2013

In total, 131 Escherichia coli isolates from surface seawater of the Gomso Bay, of Korea, were analyzed for their susceptibility to 22 different antimicrobials and for genes associated with antimicrobial resistance and virulence. According to the disk diffusion susceptibility test, the resistance to tetracycline was most prevalent (33.6%), followed by that to ampicillin (22.1%), ticarcillin (22.1%), and trimethoprim (16.8%). More than 46.6% of the isolates were resistant to at least one antimicrobial, and 22.9% were resistant to three or more classes of antimicrobials; these were consequently defined as multidrug resistant. We further found that 29 ampicillin-resistant isolates possessed genes encoding TEM-type (93.1%) and SHV-type (6.9%) ${\beta}$-lactamases. Among the 44 tetracycline-resistant isolates, tetA and tetC were found in 35 (79.5%) and 19 (43.2%), respectively, whereas tetB was detected in only three isolates (6.8%). With regard to virulence genes, merely 0.8% (n = 1) and 2.3% (n = 3) of the isolates were positive for the enteroaggregative E. coli-associated plasmid (pCVD432) gene and the enteropathogenic E. coli-specific attaching and effacing (eae) gene, respectively. Overall, these results not only provide novel insight into the necessity for seawater sanitation in Gomso Bay, but they help reduce the risk of contamination of antimicrobial-resistant bacteria.