• Journal of Life Science
• /
• v.15 no.2 s.69
• /
• pp.202-210
• /
• 2005

Following ingestion, Salmonella must adhere to and colonize the intestinal epithelium of the host in order to establish infection. S. typhimurium synthesize several appendages that are believed to mediate attachment. These include type 1 fimbriae, plasmid-encoded (PE) fimbriae, long polar (LP) fimbriae, and thin aggregative fimbriae. However, the precise roles of these putative adhesins remain unclear, due to conflicting data in the literature. We constructed strains lacking four different fimbriae including type 1 fimbriae, PE fimbriae, LP fimbriae, and thin aggregative fimbriae, as well as strains lacking each fimbriae alone. In cell culture adhesion assays, these mutants adhered to several mammalian cell lines as well as wild-type S. typhimurium. These strains were also screened for virulence in mice, and all strains were virulent or nearly as virulent as their wild-type parents. In contrast, When a strain lacking four fimbriae was screened for virulence in chicks, it was found to be highly attenuated. This suggests a role for either type 1 fimbriae, PE fimbriae, LP fimbriae or thin aggregative fimbriae or a combination of thease fimbriae in the colonization of chicks. It also suggests that differences exist with respect to the surface structures that mediate attachment of Salmonella in chicks as compared with mice.

• Korean Journal of Microbiology
• /
• v.44 no.3
• /
• pp.221-227
• /
• 2008

Bordetella pertussis is pathogenic bacteria causing pertussis, a infectious respiratory disease for the infants. The incidence rate of pertussis was significantly decreased after introduction of vaccine. However, increased pertussis cases are recently reported in several countries with high vaccine coverage. One of the inferred reasons is genotype or serotype variation between circulating strains and vaccine strains. Therefore, it is required to confirm the variation status of the isolates by genotype or serotype analysis and the possibility of pertussis outbreak in Korea should be estimated. For this, the serotype variations of the isolates from $1999\sim2006$ were investigated in agglutinogen and fimbriae. As the result, the most frequent serotype in the isolated strains was agglutinogen 1 and fimbriae 2 serotypes. Moreover, serotype transition from vaccine serotypes to non-vaccine serotypes was observed. Especially, the transition pattern of agglutinogen serotype was directed to increase a different type (agg 1) from the vaccine type (agg 1,2). However, in case of fimbriae, the same type (fim 2) with vaccine strain was increased. These results were also observed in other countries with increasing incidence of pertussis. For more predictable results to know increasing possibility of pertussis incidence in Korea, the studies on genetic variations of antigenic determinant genes and prevalence of antibody titer in normal population should be performed in the further.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.5
• /
• pp.731-737
• /
• 2013

Seventy-four Shiga toxin-producing Escherichia coli (STEC) isolates belonging to the serotype O91:H21 were isolated from 1,643 asymptomatic human carriers in a STEC outbreak at Gwangju in Korea. Although the isolates did not cause any symptoms, all of them produced Shiga toxins 1 (Stx1) and 2 (Stx2). In order to determine why these strains cause no symptoms, we explored the differences in virulence potential between the asymptomatic STEC O91:H21 isolates and symptomatic STEC O91:H21 strains (ATCC 51435 and ATCC 51434). The asymptomatic STEC O91:H21 isolates showed strongly reduced cytopathic effects compared with the symptomatic strains when intact bacterial cells were used as an inoculant. Moreover, we found a reduced adherence phenotype when testing asymptomatic strains on HeLa cells. Real-time quantitative PCR results suggest that transcriptional repression of the genes encoding type-1 fimbriae occurs in the asymptomatic isolates but not in the symptomatic strains.

• Journal of Life Science
• /
• v.15 no.4 s.71
• /
• pp.553-560
• /
• 2005

The stf (Salmonella typhimurium fimbriae) operon consisting of stfA(CDEFG assumes to encode putative fimbriae. The complete stf operon is existed in S. typhimurium and S. choleraesuis, whereas it is absent in S. typhi. Analyses of the amino acid residues between major subunit StfA of the Stf fimbriae and those of known other fimbriaes suggested that Stf belongs to class I type fimbriae. Through comparison of StfD chaperone with the other fimbrial chaperones, and of C-terminus in subunits of Stf fimbriae, it belongs to FGS (with a short Fl-G1 loop) subfamily. In order to investigate the expression of stf operon, we have constructed a Salmonella strain containing a chromosomal stfA::lacZYA transcriptional fusion, resulting in S. typhimurium $_X8532$. The strain $_X8532$ lacked the expression of \beta-galactosidase$ under normal culture conditions. However, with longer incubation time of the S. typhimurium $_X8532$, we have isolated 21 individual strains exhibiting $Lac^+$ phenotype. $Lac^+$ phenotype was appeared as approximately 0.03 frequency per generation. All isolates expressed lacZ constitutively in the various environmental conditions. Various global regulatory proteins including RpoS, OmpR, and CpxR were not involved in the regulation of the stf operon. A S. typhimurium $_X8661$ mutant lacking stfAC function attenuated 6.7 folds more than that of wild type $_X3761$ in the mouse virulence test, suggesting in the somehow involved in the Salmonella pathogenesis.

• Journal of Veterinary Clinics
• /
• v.28 no.3
• /
• pp.297-302
• /
• 2011

Avian pathogenic Escherichia coli (APEC) causes a number of extraintestinal diseases in poultry. A virulence factor, P-fimbriae is firmly associated with the diseases. In this study, to develop an effective vaccine for the prevention of APEC, recombinant attenuatted Salmonella Typhimurium vaccines expressing PapA and PapG of P-fimbriae were evaluated whether these induced protective immune responses in murine models. Female BALB/c mice were primed and boosted orally at 7 and 10 weeks of age. In all immunized mice, the antigen-specific serum IgG levels were remained higher than those in the control mice from the fourth week post inoculation till the end of this study. In addition, antigen-specific serum IgG levels in the prime-booster immunized mice were enhanced as compared to the single immunized mice among each immunized group. The antigen-specific mucosal IgA levels in the mice immunized with each strain also induced higher than those in control mice. In addition, serum IgG and fecal IgA levels in mice administered with the combination of both strains were highly induced compared to those in mice immunized with each strain alone. These results indicated that PapA and PapG worked together for inducing high immune responses. To partly discern the nature of immunity induced by the strains, we quantified serum IgG subtypes IgG1 and IgG2a specific to antigens. The PapA and PapG strains biased the immunity to the Th1-type, as determined by the IgG2a/IgG1 ratio. On the other hand, the immunization with the both strains in combination produced mixed Th1- and Th2-type immune responses. These indicated that immunization with the combination of PapA and PapG could elicit both humoral and cell-mediated immunities.

• Journal of Periodontal and Implant Science
• /
• v.35 no.1
• /
• pp.31-41
• /
• 2005

Fimbriae (fimA) of Porphyromonas gingivalis are filamentous components on the cell surface and are thought to play an important role in the colonization and invasion of periodontal tissue. P. gnigivalis fimA gene encoding fimbrillin, a subunit of fimbriae, has been classified into 5 genotypes (types I to V) based on the nucleotide sequences. In the present study, we examined the prevalence of these fimA genotypes in patients with dental implant and the relationship between prevalence of these genotypes and peri-implantitis. Dental plaque specimens obtained from 80 peri-implant sulci of 50 patients with dental implants were analyzed by 16S rRNA fimA gene-directed PCR assay. P. gingivalis were detected in 74.4% of the samples of the control group (healthy peri- implant sulci; probing depth<5mm) and in 92.0% of the samples of the test group (peri-implant sulci with peri-iimplantitis; probing $depth{\geqq}5mm$). Among the P. gingivalis-positive samples of the control group, the most prevalent fimA type was type I (29.3%), followed by type II (26.8%). In contrast, a majority among the P. gingivalis-positive samples of the test group was type II (56.S%), followed by type I (43.5%). TypeII fimA genotype organisms were detected more frequently in the test group and a significant difference in the occurrence of type II was observed between test and the control groups. A correlation between specific fimA types and peri-implant health status was found in type II (OR 3.545) and only a weak relationship was revealed in typeIV(OR 3.807). These findings indicate that P. gingivalis strains that possess type II fimA are predominant in peri-implant sulci with peri-implantitis and are closely associated with peri-implant health status. P. gingivalis with type II fimA may be involved in peri-implantitis.

• Journal of Life Science
• /
• v.15 no.4 s.71
• /
• pp.641-646
• /
• 2005

An approximately 10-fold higher level of adherence of Salmonella typhimurium strain TML to Int-407 cells was observed with organisms grown in Luria broth or in high-iron containing medium than those grown in low-iron containing medium. Iron specifically enhanced adherence, while other cations such as calcium, cobalt, copper, potassium, magnesium and manganese did not. It was suggested that iron did not act as a passive ligand - probably it stimulated production of bacterial factors necessary for adherence. A similar pattern of iron modulation of adhesiveness was also seen in Salmonella mutants with single or different combinations of multiple mutations in genes encoding the mannose sensitive hemagglutinin (type 1 fimbriae), mannose resistant hemagglutinin and flagellum. The adhesiveness of an isogenic fur mutant was modulated by iron in a manner similar to the wild-type strain, suggesting that iron modulation of adherence is independent of the fur gene product.

• Korean Journal of Veterinary Research
• /
• v.26 no.1
• /
• pp.79-85
• /
• 1986

This paper deals with the isolation of Salmonella on 3 herds during the period from May 1984 to May 1985. Isolated Salmonella were examined for serotypes, adhesive fimbriae, antibiotic susceptibility and detection of R plasmid. The results were as follows; Of total 1505 cattle, 24 Salmonella were isolated from 18 cattle (1.2%) and their serotypes were S. enteritidis (9 strains), S. derby(4 strains), S. infantis (1 strain), $C_1$ group(8 strains), $C_2$ group(1 strain) and untypable(1 strain). Twelve strains of Salmonella were isolated from 227 cattle with diarrhea and their serotypes were S. enteritidis(4 strains), S. derby(3 strains), S. infantis(1 strain), $C_1$ group(3 strains) and untypable(1 strain). The isolation rate of Salmonella in cattle varied from 1.6 to 0.9% in 3 herds, it was higher in summer and autumn and lower with the age. Of total 24 strains, 23 were adhesive type 1 fimbriae. Antibiotic susceptibility test of Salmonella isolated was performed by the agar dilution method, using 9 antibiotics as follows: ampicillin(Am), chloramphenicol(Cm), gentamicin(Gm), kanamycin(Km), nalidixic acid(Na), rifampicin(Rf), streptomycin(Sm), sulfadimethoxine(Su) and tetracycline(Tc). All the strains tested were susceptible to Am, Cm, Gm, Km, Na, Rf and Tc. Of total 24 strains, 23(95.8%) were resistant to Su and 14(58.3%) to Sm. Of the 23 resistant Salmonella strains, all the strains were found to carry R plasmid. Among them, two strains which had the R plasmid conferring SmSu resistance was transferable at $25^{\circ}C$ only.

• Journal of Periodontal and Implant Science
• /
• v.46 no.1
• /
• pp.35-45
• /
• 2016

Purpose: Porphyromonas gingivalis fimA is a virulence factor associated with periodontal diseases, but its role in the pathogenesis of peri-implantitis remains unclear. We aimed to evaluate the relationship between the condition of peri-implant tissue and the distribution of P. gingivalis fimA genotypes in Koreans using a new primer. Methods: A total of 248 plaque samples were taken from the peri-implant sulci of 184 subjects. The control group consisted of sound implants with a peri-implant probing depth (PD) of 5 mm or less with no bleeding on probing (BOP). Test group I consisted of implants with a peri-implant PD of 5 mm or less and BOP, and test group II consisted of implants with a peri-implant PD of more than 5 mm and BOP. DNA was extracted from each sample and analyzed a using a polymerase chain reaction (PCR) with P. gingivalis -specific primers, followed by an additional PCR assay to differentiate the fimA genotypes in P. gingivalis-positive subjects. Results: The Prevalence of P. gingivalis in each group did not significantly differ (P>0.05). The most predominant fimA genotype in all groups was type II. The prevalence of type Ib fimA was significantly greater in test group II than in the control group (P<0.05). Conclusions: The fimA type Ib genotype of P. gingivalis was found to play a critical role in the destruction of peri-implant tissue, suggesting that it may be a distinct risk factor for periimplantitis.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.3
• /
• pp.542-551
• /
• 2017

Small phytochemicals have been successfully adopted as antibacterial chemotherapies and are being increasingly viewed as potential antibiofilm agents. Some of these molecules are known to repress biofilm and toxin production by certain bacterial and yeast pathogens, but information is lacking with regard to the genes allied with biofilm formation. The present study was performed to investigate the inhibitory effect of burdock root extract (BRE) and of chlorogenic acid (CGA; a component of BRE) on clinical isolates of Klebsiella pneumoniae. BRE and CGA exhibited significant antibiofilm activity against K. pneumoniae without inflicting any harm to its planktonic counterparts. In vitro assays supported the ${\beta}$-lactamase inhibitory effect of CGA and BRE while in silico docking showed that CGA bound strongly with the active sites of sulfhydryl-variable-1 ${\beta}$-lactamase. Furthermore, the mRNA transcript levels of two biofilm-associated genes (type 3 fimbriae mrkD and trehalose-6-phosphate hydrolase treC) were significantly downregulated in CGA- and BRE-treated samples. In addition, CGA inhibited biofilm formation by Escherichia coli and Candida albicans without affecting their planktonic cell growth. These findings show that BRE and its component CGA have potential use in antibiofilm strategies against persistent K. pneumoniae infections.