A new phage-ty-ing scheme for strains ofProteus mirabilis andProteus vulgaris

The results of serological and genetic analyses of 21 phages ofProteus mirabilis andProteus vulgaris of the new typing set confirmed their classification into morphological types A1, A2, B1, and C1 and the familiesMyoviridœ, Siphoviridœ andPodoviridœ. Phages and antisera reacted and cross-reacted only within each family. In DNA-DNA hybridization, DNA fragments reacted only with³²P-labelled DNA probes of their own families. Serological and genetic analysis showed that some phages in the familiesMyoviridœ andPodoviridœ were so closely related that they could be considered identical. First part:Folia Microbiol. 39, 381–386 (1994).     

A new bacteriophage typing scheme forProteus mirabilis andProteus vulgaris strains

The lytic properties of 21 bacteriophages constituting a new typing set forProteus were examined in 507Proteus mirabilis and 29P. vulgaris strains isolated from patients and healthy subjects. Comparison of their morphological, serological, genetic and lytic properties showed that, in theMyoviridae andPodoviridae families, some phages were so closely related that the presence of all of them in the set was redundant. Analysis of the lytic properties revealed that some of the bacteriophages were not active enough to facilitate the differentiation ofProteus strains The size of the final typing set was reduced from 21 to 12 phages but it was suggested that, in order to improve the differentiation capacity of the set, new phages should be included. Second part:Folia Microbiol. 41, 137–140 (1996).     

A new phage typing scheme forProteus mirabilis andProteus vulgaris strains

A new bacteriophage typing set, composed of 22 phages, was established as a tool for differentiation ofProteus strains. All the phages were tailed and included 4 morphological types (A1, A2, B1 and C1). They were classified into the familiesMyoviridae, Siphoviridae andPodoviridae. From the set, 19 phages had double-stranded DNA and 3 were single-stranded DNA phages.     

Adhesion of human bifidobacterial strains to cultured human intestinal epithelial cells and inhibition of enteropathogen-cell interactions.

Thirteen human bifidobacterial strains were tested for their abilities to adhere to human enterocyte-like Caco-2 cells in culture. The adhering strains were also tested for binding to the mucus produced by the human mucus-secreting HT29-MTX cell line in culture. A high level of calcium-independent adherence was observed for Bifidobacterium breve 4, for Bifidobacterium infantis 1, and for three fresh human isolates from adults. As observed by scanning electron microscopy, adhesion occurs to the apical brush border of the enterocytic Caco-2 cells and to the mucus secreted by the HT29-MTX mucus-secreting cells. The bacteria interacted with the well-defined apical microvilli of Caco-2 cells without cell damage. The adhesion to Caco-2 cells of bifidobacteria did not require calcium and was mediated by a proteinaceous adhesion-promoting factor which was present both in the bacterial whole cells and in the spent supernatant of bifidobacterium culture. This adhesion-promoting factor appeared species specific, as are the adhesion-promoting factors of lactobacilli. We investigated the inhibitory effect of adhering human bifidobacterial strains against intestinal cell monolayer colonization by a variety of diarrheagenic bacteria. B. breve 4, B. infantis 1, and fresh human isolates were shown to inhibit cell association of enterotoxigenic, enteropathogenic, diffusely adhering Escherichia coli and Salmonella typhimurium strains to enterocytic Caco-2 cells in a concentration-dependent manner. Moreover, B. breve 4 and B. infantis 1 strains inhibited, dose dependently, Caco-2 cell invasion by enteropathogenic E. coli, Yersinia pseudotuberculosis, and S. typhimurium strains.     

Adhesion of marine cryptic Escherichia isolates to human intestinal epithelial cells

Five distinct cryptic lineages (clades I–V) have recently been recognized in the Escherichia genus. The five clades encompass strains that are phenotypically and taxonomically indistinguishable from Escherichia coli sensu stricto; however, scant data are available on their ecology, virulence and pathogenic properties. In this study 20 cryptic E. coli strains isolated from marine sediments were investigated to gain insights into their virulence characteristics and genetic traits. The ability to adhere to intestinal cells was highest among clade V strains, which also harbored the genes involved in gut colonization as well as the genes (pduC and eut operon) typically found in environmentally adapted E. coli strains. The pduC gene was significantly associated with clade V. Multilocus sequence typing of three representative clade V isolates revealed new sequence types (STs) and showed that the strains shared two allelic loci (adk 51 and recA 37). Our findings suggest that cryptic Escherichia lineages are common in coastal marine sediments and that this habitat may be suitable for their growth and persistence outside the host. On the other hand, detection in clade V strains of a gene repertoire and adhesion properties similar to those of intestinal pathogenic strains could indicate their potential virulence. It could be argued that there is a dual nature of cryptic clade V strains, where the ability to survive and persist in a secondary habitat does not involve the loss of the host-associated lifestyle. Clade V could be a group of closely related, environmentally adapted E. coli strains.     

Adhesion of Vibrio cholerae 01 to human buccal epithelial cells in vitro

Abstract Adhesive capacity to human buccal cells (HBC) of Vibrio cholerae 01 was expressed optimally in synthetic culture medium. Bacterial adhesion was inhibited efficiently by fetuin and weakly by D -mannose, D -glucose and thyroglobulin. Pretreatment of HBC with neuraminidase, protease or trypsin reduced the adhesion of V. cholerae 01 cells.     

Aggregative adherence of uropathogenic Proteus mirabilis to cultured epithelial cells

Proteus mirabilis is an important cause of urinary tract infection (UTI) in patients with complicated urinary tracts. Thirty-five strains of P. mirabilis isolated from UTI were examined for the adherence capacity to epithelial cells. All isolates displayed the aggregative adherence (AA) to HEp-2 cells, a phenotype similarly presented in LLC-MK(2) cells. Biofilm formation on polystyrene was also observed in all strains. The mannose-resistant Proteus-like fimbriae (MR/P), Type I fimbriae and AAF/I, II and III fimbriae of enteroaggregative Escherichia coli were searched by the presence of their respective adhesin-encoding genes. Only the MR/P fimbrial subunits encoding genes mrpA and mrpH were detected in all isolates, as well as MR/P expression. A mutation in mrpA demonstrated that MR/P is involved in aggregative adherence to HEp-2 cells, as well as in biofilm formation. However, these phenotypes are multifactorial, because the mrpA mutation reduced but did not abolish both phenotypes. The present results reinforce the importance of MR/P as a virulence factor in P. mirabilis due to its association with AA and biofilm formation, which is an important step for the establishment of UTI in catheterized patients.     

Adherence of fimbriate and non-fimbriate strains of Yersinia enterocolitica to human epithelial cells

Strains of Yersinia enterocolitica from different O serogroups were tested for their ability to adhere to cultured epithelial cells (H.Ep 2) after growth of bacteria in broth at 22 C or 37 C. Strains that adhered to H.Ep 2 cells generally did so better after growth at 22 C than at 37 C. The data indicate that the ability to produce either of the mannose-resistant (MR) hemagglutinins, MR/Y or K1, each associated with fimbriae, does not correlate with ability to adhere to epithelial cells in this particular in vitro model.     

Adhesion of human amnion epithelial cells to extracellular matrix : Evidence for multiple mechanisms

Human amnion epithelial cells attach and flatten slowly (approximately 65 min) onto plastic in the presence of serum but much more rapidly (20-30 min) onto subcellular matrix (SCM) deposited by the same cells. This matrix contains both fibronectin and laminin, but neither molecule on its own can reproduce its adhesive properties. Cells attach on surfaces containing fibronectin and laminin and extend filopodial and lamellipodial areas of cytoplasm without extensive flattening in the perinuclear region. Matrix deposited onto plastic by amnion epithelial cells has trypsin-sensitive and trypsin-resistant, papain-sensitive adhesion-promoting components. Cell spreading triggered by the latter but not the former can be inhibited by pretreating the adhering cells with heparin. Other GAGs are without effect. The results are discussed in terms of multiple interactions between epithelial cells and basal laminae.     

Adhesion of enteropathogenic Escherichia coli to host cells

Enteropathogenic Escherichia coli (EPEC) adhere to the intestinal mucosa and to tissue culture cells in a distinctive fashion, destroying microvilli, altering the cytoskeleton and attaching intimately to the host cell membrane in a manner termed the attaching and effacing effect. Typical EPEC strains also form three-dimensional microcolonies in a pattern termed localized adherence. Attaching and effacing, and in particular intimate attachment requires an outer membrane adhesin called intimin, which binds to the translocated intimin receptor, Tir. Tir is produced by the bacteria and delivered to the host cell via a type III secretion system. In addition to this well-established adhesin-receptor pair, numerous other adhesin interactions between EPEC and host cells have been described including those between intimin and cellular receptors and those involving a bundle-forming pilus and flagella and unknown receptors. Much additional work is needed before a full understanding of EPEC adhesion to host cells comes to light.     

Adhesion of Salmonella dublin to HEp2 epithelial cells

Two strains of Salmonella dublin , grown serially in brain heart infusion broth, were motile and produced mannose sensitive (MS) but not mannose resistant (MR) haemagglutinins; grown on phosphate buffered agar, the strains were poorly motile and phenotypically MSHA^- MRHA ⁺. In adhesion tests with HEp2 epithelial cells, broth grown bacteria that were motile and MSHA⁺ MRHA^- adhered better than agar grown bacteria that were poorly motile and MSHA^- MRHA⁺. Thus, in adhesion tests with HEp2 epithelial cells, strains of S. dublin behaved like S. typhimurium strains in that their HEp2 cell adhesiveness was associated with motility and production of MSHA.     

Adhesion of group B streptococci to vaginal epithelial cells

The work presents the results of studies on the optimum and standard conditions for the in vitro determination of the adhesiveness of group B streptococci with epithelial cell suspensions. Vaginal epithelium has proved to be the most convenient and adequate system for studying the adhesiveness of group B streptococci. The optimum infective dose of these bacteria has been found to range from 50 to 200 cocci per cell. The characteristics of the adhesion of group B streptococci to vaginal epithelium are highly reproducible and exhibit low dependence on the time of the incubation of the bacteria with epithelial cells; fluctuations in the adhesiveness of the cultures in the definite range of pH shifts are seemingly determined by the serotype of the strains.     

Galectin-3-mediated adherence of Proteus mirabilis to Madin-Darby canine kidney cells.

Proteus mirabilis is an important cause of urinary tract infections (UTIs) and can result in acute pyelonephritis. Proteus mirabilis expresses several, morphologically distinct, fimbrial species, and previous studies have shown that the nonagglutinating fimbriae (NAF) mediate bacterial adherence to a number of cell lines, including Madin-Darby canine kidney (MDCK) cells. Immunoblot overlay analysis of the plasma membrane fraction from MDCK cells with purified NAF revealed a 34-kDa band, which has been analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Database search identified galectin-3 as a potential protein candidate. Immunocytochemical assay of MDCK cells with a galectin-3-specific monoclonal antibody, anti-Mac-2, confirmed its presence on the plasma membrane extracellular surface. Preincubation of P. mirabilis with anti-Mac-2 monoclonal antibodies, specific for galectin-3, resulted in the inhibition of bacterial binding to MDCK cells. These data suggest a role for galectin-3, interacting with appropriately glycosylated surface receptors and P. mirabilis fimbriae, as a mediator of bacterial adherence in vitro.     

Adhesion of Escherichia coli to human kidney cryostat sections

Abstract A method for studying adhesion of fluorochrome-stained Escherichia coli to cryostat sections of human kidney is described. Of the 3 model strains used, the P-fimbriated strain KS71 adhered more effectively than the type-1-fimbriated or nonfimbriated strains. Adhesion of KS71 was inhibited specifically by anti-P-fimbriae Fab fragments, and it was concluded that P-fimbriae mediate E. coli adhesion in the kidneys.     

Adhesion of Proteus mirabilis and Proteus vulgaris to uroepithelial cells following exposure to various antimicrobial agents.

The effect of subinhibitory concentrations of netilmicin, ceftriaxone, cefotaxime, aztreonam and piperacillin on the adherence of Proteus species to uroepithelial cells was examined. Bacterial adhesion to human uroepithelial cells, measured microscopically, was affected by all five antibiotics but to different extents. The most effective was netilmicin. There was a correlation between the decreased rate of bacterial attachment and morphological changes in the drug-exposed bacteria.     

Adhesion of Lactobacillus isolates to intestinal epithelial cells of chicken

L.Z. JIN, Y.W. HO, M.A. ALI, N. ABDULLAH, K.B. ONG AND S. JALALUDIN. 1996. A total of 46 Lactobacillus isolates obtained from chicken intestine were assessed on their ability to adhere to the chicken ileal epithelial cell (IEC) in vitro . Twelve out of the 46 isolates showed moderate to good ability to adhere to the IEC. Temperature (between 4°C and 42°C) did not affect attachment. Incubation (contact) time of 30 min was found to be insufficient for the attachment of bacteria to the IEC, but contact time beyond 1 h did not increase this ability. The pH values (4–7) of the suspending buffer did not have any significant effect on the attachment of bacteria to the IEC, but at pH 8 it was reduced significantly (P < 0.05).