Curli fimbria: an Escherichia coli adhesin associated with human cystitis

Abstract Escherichia coli is the major causative agent of human cystitis. In this study, a preliminary molecular analysis carried out by PCR (polymerase chain reaction) demonstrated that 100% of 31 E. coli strains isolated from patients with recurrent UTIs (urinary tract infections) showed the presence of the curli fimbria gene (csgA). Curli fimbria is known to be associated with bacterial biofilm formation but not with the adhesion of human cystitis-associated E. coli. Therefore, this work aimed to study how curli fimbria is associated with uropathogenic E. coli (UPEC) as an adhesion factor. For this purpose, the csgA gene was deleted from strain UPEC-4, which carries three adhesion factor genes (csgA, fimH and ompA). The wild-type UPEC-4 strain and its mutant (ΔcsgA) were analyzed for their adhesion ability over HTB-9 (human bladder carcinoma), Vero (kidney cells of African green monkey) and HUVEC (human umbilical vein) cells in the presence of α-D-mannose. All the wild-type UPEC strains tested (100%) were able to adhere to all three cell types, while the UPEC-4 ΔcsgA mutant lost its adherence to HTB-9 but continued to adhere to the HUVEC and Vero cells. The results suggest that curli fimbria has an important role in the adhesion processes associated with human UPEC-induced cystitis.

Evaluation of the role of Mycobacterium tuberculosis pili (MTP) as an adhesin, invasin, and cytokine inducer of epithelial cells

Abstract This study was undertaken in order to assess the involvement of Mycobacterium tuberculosis pili (MTP) as an adhesin, invasin, and cytokine inducer in the M. tuberculosis-epithelial cell interaction. A MTP-deficient strain of M. tuberculosis demonstrated a significant reduction of 69.39% (p = 0.047) and 56.20% (p = 0.033) in its ability to adhere to and invade A549 pulmonary epithelial cells, respectively, in comparison with the wild-type strain. Complementation of the MTP-deficient mutant restored its adhesion and invasion capacity back to the wild-type levels. Overall, it was found that similar concentrations of IL-1β, IL-4, IL-6, IL-8, G-CSF, IFN-γ, MCP-1, and TNF-α were induced in A549 cells infected with the MTP-proficient and MTP-deficient strains. However, at 48 h post-infection, the MTP-deficient mutant induced significantly lower levels of TNF-α than the wild-type strain (p = 0.033). Furthermore, at 72 h post-infection, the mutant induced significantly higher levels of IL-8 than the wild-type (p = 0.005). We conclude that MTP is an adhesin/invasin of epithelial cells and, while playing a role in M. tuberculosis entry, they do not appear to largely influence the epithelial cell cytokine response.

Detection of virulent of Klebsiella isolates from ñlinical samples / Монголын Анагаах Ухаан

IntroductionKlebsiella spp is a well-known opportunistic pathogen associated with nosocomial infections such asurinary tract, septicaemia and pneumonia number of multi-drug resistant strains and infections causedby Klebsiella has progressively increased, causing treatment limitations.GoalIdentify of phenotype of Klebseilla isolates from ñlinical samplesMaterials and MethodsA total of 112 Klebsiella strains were isolated from clinical samples in State Central First Hospital and StateCentral Third Hospital from July 2015 through December 2015. The bacterial isolates were identifi edaccording to cultural characteristics, biochemical test and API20E. The serum resistance, capsule andhypermucoviscosity, cell surface protein (curly), a-hemolysin and ability to form biofi lm were sought byphenotypic assays. Antimicrobial susceptibility was tested by diffusion method.ResultA total of 112 Klebsiella samples were collected. The bacterial isolates were identifi ed according tocultural characteristics, biochemical test and API20E, the results revealed that 16.1 percent isolateswere identifi ed as K.oxytoca all of them 83.9 percent isolates were belong to K.pneumonia. Therewere observed for ampicillin (99 percent), nitrofurantoin (53.6 percent), cepalotin (50.6 percent) and51 percent of isolates were considered as a multiple drug resistant. Serum resistance properties ofK.pneumoniae was resistance 89.4 percent, intermediately susceptible 4.3 percent, sensitive 6.4percent and for K.oxytoca resistance 88.9 percent, intermediately susceptible 5.6 percent, sensitive 5.6percent. The hemolysin àalpha was detected in 32.2 percent, and gamma, beta in 66.96 percent, 0.9percent respectively. The capsule was observed in 46.5 percent and hypermucoviscosity in 27.7 percentof isolates. The cell surface protein (curly) and biofi lm were detected in 100 percent.Conclusion:Both K.pneumoniae and K.oxytoca isolates from clinical samples have similar virulent properties, andthe a-hemolysin and hypermucoviscosity positive isolates were more resistance to antibiotics.

Relation between adherence factors and the phylogenetic group of extraintestinal pathogenic Escherichia coli / Шинэ санаа Шинэ нээлт

Extraintestinal pathogenic Escherichia coli (ExPEC), the specialized strains ofE.coli that cause most extraintestinal infections, represent a major but littleappreciated health threat. Phylogenetic analysis has shown that ExPEC is composedof four main phylogenetic groups (A,B1, B2, and D) and that virulent extraintestinalstrains mainly belong to groups B2 and D.In this study, we aimed to assess therelation between adherence virulence and phylogenetic groups of ExPEC.A total of 161 E.coli samples were collected. Out of these 17 (10.6%) werefrom pus, 66 (41 %) from urine, 78 (48.4%) from cervical swab. The phylogeneticgroups and 6 virulence genes (fimH, papC, papGII, papGIII, fa/draBC,andSfa/focDE) encoding adhesins were identified by triplex PCR. Phylogeneticgroups distribution was as follows: B1 10.5%, A 24.7%, B2 25.3%, and D 38.9%. Virulence genes prevalence was fimH 90.1%, papC 23%, papGII 16.8%, papGIII1.9%, Afa/draBC 11.8%, andSfa/focDE 5.6%. The cell surface protein (curli) wasdetected 50,3% by Congo red agar. In conclusion: The most isolated strainsbelonged to the phylogenetic group B2 and D. The phylogenetic groups weresignificantly associated with some genes encodingadhesins (fimH, papC) and cellsurface protein (curli).

Relation between adherence factors and the phylogenetic group of extraintestinal pathogenic Escherichia coli / Шинэ санаа Шинэ нээлт

Extraintestinal pathogenic Escherichia coli (ExPEC), the specialized strains ofE.coli that cause most extraintestinal infections, represent a major but littleappreciated health threat. Phylogenetic analysis has shown that ExPEC is composedof four main phylogenetic groups (A,B1, B2, and D) and that virulent extraintestinalstrains mainly belong to groups B2 and D.In this study, we aimed to assess therelation between adherence virulence and phylogenetic groups of ExPEC.A total of 161 E.coli samples were collected. Out of these 17 (10.6%) werefrom pus, 66 (41 %) from urine, 78 (48.4%) from cervical swab. The phylogeneticgroups and 6 virulence genes (fimH, papC, papGII, papGIII, fa/draBC,andSfa/focDE) encoding adhesins were identified by triplex PCR. Phylogeneticgroups distribution was as follows: B1 10.5%, A 24.7%, B2 25.3%, and D 38.9%. Virulence genes prevalence was fimH 90.1%, papC 23%, papGII 16.8%, papGIII1.9%, Afa/draBC 11.8%, andSfa/focDE 5.6%. The cell surface protein (curli) wasdetected 50,3% by Congo red agar. In conclusion: The most isolated strainsbelonged to the phylogenetic group B2 and D. The phylogenetic groups weresignificantly associated with some genes encoding adhesins (fimH, papC) and cellsurface protein (curli).

The detection of adherence factorsby Escherichia coli cause of urinary tract infectionsin Ulaanbaatar, Mongolia / Монголын Анагаах Ухаан

INTRODUCTION: Urinary tract infections among the most common bacterial infectious diseases encountered at all ages. Escherichia coli are being the etiologic agent in 50–80%. Therefore, it is an important public health problem. E.coli causing urinary tract infections express pilli, fimbriae and others adherence virulence factors. GOAL: To detect the some adherence virulence factors of Uropathogenic Escherichia coli (UPEC) in Ulaanbaatar, Mongolia MATERIALS AND METHODS: A total of 76E.colisampleswere collected. These samples were positive bacteriological examination of urine, performed at the bacteriological laboratory of the State Central Third Hospital and State Central First Hospital, Ulaanbaatar, Mongolia. The biofilm formation was evaluated by the growth rate of E.coli on plastic surface.The detection of the virulence factors type 1 fimbriae (fimA gene) and P-fimbriae (papC) was performed by multiplex PCR using gene specific primers.Curli expression was determined by using congo red agar. RESULTS: The evaluation of bacterial biofilm formation using 96 well plates showed 40 negative (52.6%), 32 weak biofilm (42.1%) and 4 moderate biofilm (5.3%) formation for E.coli and no strong biofilm forming strain was detected. The cell surface protein (curli) was detected by Congo red agar. The result was 71% positive for studied E.coli strains. The detection result of pili genes by multiplex PCR showed that fimH gene detected for 73 (96.1%) and papC gene detected for 18 (23.7%) E.coli cultures. CONCLUSION: Almost half of surveyed Uropathogenic E.coli isolated in Ulaanbaatar, Mongolia had ability of biofilm formation and it has been determined by the bacterial surface protein (curli), which is one of bacterial adherence factors, may cause biofilm formation.

Escherichia coli O157:H7 adherence to HEp-2 cells is implicated with curli expression and outer membrane integrity

Escherichia coli (E. coli) has ability to express thin aggregative fimbriae, known as curli, on the cell surface. Previously, a few example of curli expression in serogroup O157:H7 of enterohemorrhagic E. coli (EHEC) were reported, compared to other E. coli groups. However, significance of curliation in the EHEC pathobiology has not been described well in the literature. A highly curliated O157:H7 strain was used in this study in order to elucidate role of curliation in EHEC adherence to cultured HEp-2 cells. The expression of curli in the EHEC isolate was consistent with strong positive indication of Congo-red (CR) binding and formation of clumps in the bottom of the tube containing Luria-Bertani (LB) broth when cultured overnight at 37 degress C. A few CR-binding negative (CR-) colonies occurred spontaneously within the population of CR+ isolate. The CR+ EHEC showed massive aggregative adhesion pattern, whereas the spontaneous CR- strain showed typical localized adherence on HEp-2 cells. Electron microscopy confirmed highly curliated bacteria in the CR+ EHEC sample. Interestingly, the curliation disappeared in a msbB1 and msbB2 double mutant derived from the CR+ EHEC. These results suggest that the compromised outer membrane integrity caused by msbB mutations may abrogate curli production in the CR+ EHEC harbouring penta-acylated lipid A structure in their outer membrane.