Mannose-resistant Research Articles

Type 1 fimbriae are important factors limiting the dissemination and colonization of mice by Salmonella Enteritidis and contribute to the induction of intestinal inflammation during Salmonella invasion.

We have recently shown that Salmonella Gallinarum type 1 fimbriae with endogenous mannose-resistant (MR) variant of the FimH protein increase systemic dissemination of S. Gallinarum and colonization of internal organs in comparison to the S. Gallinarum fimH knockout strain or the mutant expressing mannose-sensitive (MS) FimH variant from S. Enteritidis. Elaborating from these studies, we proposed that MS variants of FimH are advantageous in gastrointestinal infections, in contrast to MR FimH variants which decrease intestinal colonization and promote their systemic spreading. To support our hypothesis, we carried out in vivo studies using mice infected with wild-type S. Enteritidis and its fimH knockout strain (S. Enteritidis), which was characterized by significantly lower adhesion and invasiveness of murine ICE-1 intestinal cells. Using bioluminescence imaging, we observed that the loss of MS FimH adhesin correlates well with the highly increased colonization of mice by these bacteria. The appearance of the mutant strain was observed much earlier than wild-type Salmonella, and mice infected with 104–107 S. Enteritidis fimH::kan CFUs had significantly (P < 0.05) shorter infection-free time than animals inoculated with wild-type S. Enteritidis. Infections caused by non-typhoid Salmonella, such as S. Enteritidis, are associated with massive inflammation of the lamina propria and lymph nodes in the intestinal tract. Therefore, we evaluated the role of MS type 1 fimbriae in the induction of cytokine expression and secretion, using murine ICE-1 intestinal cells. We showed that the expression, as well as secretion, of Il-1b, Il-6, Il-10, and Il-12b was significantly higher in cells infected with wild-type S. Enteritidis compared to cells infected with the mutant strain. Based on our results, we propose that type 1 fimbriae may play an important role in the pathogenicity of S. Enteritidis and may contribute to an intestinal inflammatory response.

Isolation rate of non-hemagglutinating strains of Serratia marcescens from clinical specimens in a general hospital: comparison of serotypes O2 and O14

Given the absence of recent reports on the isolation rate of Serratia marcescens by pili type, clinical isolates from respiratory and urinary tract specimens--prime loci of infection by this organism--were subjected to examination. The 123 S. marcescens strains (serotype O2, 67 strains, serotype O14, 56 strains) used in this study were isolated from inpatients at Showa University Fujigaoka Hospital during the 5 years from April 1997 to March 2002. Higher rates of S. marcescens O2 with mannose-resistant (MR)/K Klebsiella-like pili were detected among the respiratory tract-derived strains. On the other hand, more non-hemagglutinating O14 strains were found among the urinary tract-derived strains. Analysis by study phase revealed a rise in the isolation rate of non-hemagglutinating strains, from 0-17.4% for O2 strains and 34.5%-66.7% for O14 strains, between phase I (April 1997 to March 1999) and phase II (April 1999 to March 2002) of the study. In order to examine the increasing non-hemagglutinating strains in detail, the 28 serotype O14 non-hemagglutinating strains, and 8 strains with only mannose-sensitive (MS) pili were subjected to genotyping by pulsed-field gel electrophoresis (PFGE), revealing the presence of 10 clones with disparate genotypes. The A1 strain isolated at the highest frequency was non-hemagglutinating in all cases and possessed the same genotype, indicating proliferation within the hospital over the 5 years of the study. These results indicate that non-hemagglutinating strains were transmitted among patients within the hospital.

Adherence pili of pathogenic strains of avian Escherichia coli

Fifty strains of Escherichia coli isolated from coliseptcemic chickens in Londrina, Brazil, were examined for presence of gene sequences for pil and pap, hemagglutination, and adherence to chicken tracheal cells. Forty-one strains were pil + and 22 of these showed mannose sensitive (MS) hemagglutination (MSHA) of guinea-pig erythrocytes, indicating that they possessed only type 1 pili. Seven strains were pap + and 6 of these caused mannose resistant (MR) hemagglutination (MRHA) of human erythrocytes. Twenty-four strains (17 of which caused MSHA) showed MS-adherence to chicken tracheal cells and the remaining 26 showed MR-adherence. The former typically adhered to the mucus layer whereas the latter usually adhered to the mucosal epithelium. It is concluded that MS adherence to chicken tracheal cells is correlated with expression of type 1 fimbriae and that MR-adherence to chicken tracheal cells cannot always be attributed to P pili.

Serratia marcescens.

Over the last 30 years, Serratia marcescens has become an important cause of nosocomial infection. There have been many reports concerning the identification, antibiotic susceptibility, pathogenicity, epidemiological investigations and typing of this organism. Accurate identification is important in defining outbreaks. The API 20E system has been used widely, but is not individually satisfactory. The growth of S. marcescens in the environment has been investigated in relation to water, disinfectants and plastics such as blood bags. Certain extracellular products are unique to S. marcescens. Pigment (prodigiosin) biosynthesis by S. marcescens has been investigated fully since the emergence of the organism as a cause of infection. Many other aspects of the pathogenicity and virulence of S. marcescens have been studied, including adherence and hydrophobicity, lipopolysaccharide (LPS) and extracellular products. Two modes of adhesion to host epithelial surfaces have been suggested. These are mannose-resistant (MR) pili and mannose-sensitive (MS) pili. LPS, which is responsible for the biological activity of endotoxin, has been investigated fully and 24 somatic antigens have been described. The production of different enzymes by S. marcescens as virulence factors has also been reported, including chitinase, lipase, chloroperoxidase and an extracellular protein, HasA. Antibiotics used to treat serratia infection include beta-lactam agents, aminoglycosides and fluoroquinolones and a variety of different resistance mechanisms have been demonstrated. Typing methods used to study the epidemiology of S. marcescens include biotyping, bacteriocin typing, phage typing, plasmid analysis, polymerase chain reaction amplification of enterobacterial repetitive intergenic consensus sequences (ERIC-PCR) and ribotyping. Serological typing has also been used and this method seems to be a suitable first-line typing method for S. marcescens, although some strains remain untypable. RAPD-PCR has also been applied to a small number of isolates and seems to be a promising method, especially for rapid monitoring of an outbreak and tracing the source of initial infection.

Expression of P and type 1 (F1) fimbriae in pathogenic Escherichia coli from poultry

To investigate the expression of P and type 1 (F1) fimbriae in pathogenic avian Escherichia coli, fourteen pap + fim + E. coli isolates pathogenic for poultry were grown on four complex or minimal media, and examined for the presence of mannose resistant (MR) and mannose sensitive (MS) hemagglutination (HA), and for P or for type 1 (F1) fimbriae using immunofluorescence, immunodot, and immunoblot. In addition, isolates grown under different culture conditions were examined for adherence to frozen sections of chicken trachea. Twelve of the 14 isolates were divided into three groups based on adhesin expression in the different media. Isolates of all three groups exhibited strong MSHA reactions when cultures were grown serially in static broth, and expressed a subunit protein with an apparent molecular mass of 17 to 18.5 kDa, serologically related to the F1A major fimbrial subunit. There was a good correlation between MSHA and adherence to chicken tracheal sections. Isolates of group I only demonstrated MSHA and expression of F1A fimbriae after growth in static broth. Isolates of group II demonstrated MSHA and expression of F1A fimbriae after growth in all tested media whereas isolates of group III demonstrated expression of F1A fimbriae only after growth in static broth and minimal agar. Only the five group I isolates expressed MRHA associated with P fimbrial adhesins and expressed fimbriae with a major subunit protein of 18 kDa serologically related to the F11 major fimbrial subunit. None of these five isolates grown on complex solid media, where P but not type 1 fimbriae were expressed, adhered to tracheal sections. Results suggest that i) P fimbriae are not readily expressed in vitro by most pap + fim + avian E. coli isolates; ii) environmental control of phase variation of type 1 fimbriae differs among pathogenic avian E. coli; and iii) receptors for type 1, but not for P fimbriae, are present in chicken tracheal mucosa.

Influence of some bacterial and host factors on colonization and invasiveness of Escherichia coli K1 in neonatal rats

Of 209 healthy infants examined, 44 (21.1%) carried Escherichia coli K1 in their feces. Of these 44 isolates, 36 (81.8%) were attributed to 10 different known clonal groups of E. coli K1 and 4 isolates represented unknown types. The influence of mannose-resistant (MR) adhesins, aerobactin production, and resistance to serum on colonization and invasiveness of E. coli K1 in orally infected inbred LEW baby rats was investigated. Strains expressing MR adhesins had significantly higher colonization and invasion rates than non-MR strains did. Mixed-infection experiments of LEW rats revealed interactions between different types of E. coli K1 strains affecting colonization and invasion rats. P-fimbriated strains appeared to have a selective advantage for colonization. The bacteremic potentials of different E. coli K1 strains could not be associated with their resistance to sera from LEW rats free of members of the family Enterobacteriaceae. No differences in virulence between fecal E. coli K1 isolates and clinical isolates from diseased humans were found. An influence of the major histocompatibility complex on host susceptibility to invasive E. coli K1 was indicated by comparing the parental LEW rat strain with different congenic LEW strains (RT1).

腎う腎炎とスーパーオキサイド

The role of superoxide in scar formation following renal infection caused by mannose-sensitive (MS) -piliated strains of bacteria was studied in the experimental pyclonephritis model using female Sprague-Dawley rats. The MS-piliated strain stimulated renal scarring to a significantly greater extent than either the non-piliated or mannose-resistant (MR) -piliated strains. Modification of leukocytes by administering cyclophosphamide to induce neutropenia and colchicine to inhibit leukocyte migration was effective in preventing renal scarring. Treatment with superoxide dismutase during the early stage of infection was also effective in preventing scar formation. Finally, the production of superoxide following stimulation by MS-piliated strain was larger amount than it following stimulation by either non-piliated or MR-piliated strains.These observations suggest that superoxide released from leukocytes plays an important role in the development of renal scarring following infection by MS-piliated strains.

In-vitro and in-vivo characteristics of TnphoA mutant strains of Salmonella serotype Gallinarum not invasive for tissue culture cells.

Insertion mutants of a strain of Salmonella serotype Gallinarum, the cause of fowl typhoid, were produced with transposon TnphoA. Eight mutants were identified as being less invasive in cell culture than the parent strain. Neither the parent strain nor the mutants showed mannose-sensitive haemagglutination of various red blood cell species. Although two mutants gave mannose-resistant (MR) haemagglutination of red cells of different animal species these MR activities could not be correlated with other characteristics in vitro or in vivo. The mutant strains were divisible into three classes by their patterns of invasiveness and adhesiveness in vitro and by changes in membrane proteins. Strains of classes 1 and 2 had single transposon insertions, detected by Southern hybridisation, of 8.9 and 2.4 kb EcoRV-digested chromosomal-fragments, respectively, and were slightly less invasive than the parent strain. They were no less virulent for chickens by the oral route than a mutant strain shown to be as invasive in vitro as the parent strain. The class-2 mutant was also less adhesive than the other strains. The single mutant strain of class 3 which contained insertions in several chromosomal fragments, was non-invasive in Vero cells (less than log10 1.0 cfu/ml recovered compared with log10 2.88 for the parent strain) and showed reduced virulence by both oral and intramuscular routes. The mutant strains of all classes were taken up equally rapidly from the blood by the spleen. Intramuscular immunisation of chickens with the class-3 mutant strain gave complete protection against oral challenge 3 weeks later with 1000 oral LD50 doses of the virulent parent strain.

Characterization of the type 1 fimbrial subunit gene (fimA) of Serratia marcescens

The nucleotide sequence of a DNA fragment that contains the fimA gene, encoding the major fimbrial subunit, of Serratia marcescens IA506 and associated flanking sequences has been elucidated. In addition, the origin of transcription has been identified and is located 120 base pairs upstream of the fimA initiation codon. The predicted amino acid sequence of the FimA polypeptide exhibits some degree of sequence homology with the fimbrial subunits encoded by the fimA determinants of Klebsiella pneumoniae, Salmonella typhimurium, and Escherichia coli and also to Smf2, the major structural component of mannose-resistant (MR) fimbriae of S. marcescens. The Serratia adhesin that facilitates haemagglutination mediated by type 1 fimbriae is less susceptible to inhibition by D-mannose than has been observed to be the case in other type 1 fimbrial adhesins. The molecule conferring this adherence specificity has been shown to be distinct from the fimA gene product and, therefore, is analogous to the fimbrial systems reported in other species.

Increased renal scarring by bacteria with mannose-sensitive pili

Renal scars are thought to be the end stage of chronic pyelonephritis and one of the most important causes of renal insufficiency and renal hypertension. The role of bacterial pili was examined in scar formation after an infection of newly constructed bacterial strains using the recombinant DNA technique, which possessed either mannose resistant (MR) or mannose sensitive (MS) pili of Serratia marcescens. Strains that differed in only a single virulence factor, namely, MR or MS pili, were used in a rat model of chronic pyelonephritis. In this model, MS-piliated bacteria stimulated renal scarring more severely than non-piliated or MR-piliated bacteria.

Two Kinds of P‐Fimbrial Variants of Uropathogenic Escherichia coli Recognizing Forssman Glycosphingolipid

Various types of fimbriae on pathogenic Escherichia coli strains have been classified by their antigenicities and recognition specificities for receptors. However, the antigenicity of fimbrial proteins does not always correlate with the fimbrial recognition specificity. In this communication, the exact carbohydrate structures recognized by the fimbriae of two human uropathogenic E. coli strains, KS71 (O4) and IH11024 (O6), that have P-fimbrial antigen, were examined. Strain KS71 showed mannose-resistant (MR) hemagglutination (HA) of human blood group OP1 phenotype erythrocytes, and its HA was inhibited by blood group Pk antigen, Gal(alpha,1-4)Gal(beta,1-4)Glc-ceramide and P antigen, GalNAc(beta,1-3)Gal (alpha,1-4)Gal(beta,1-4)Glc-ceramide but not by Forssman antigen, GalNAc(alpha,1-3)GalNAc(beta,1-3)Gal(alpha,1-4)Gal (beta,1-4)Glc-ceramide, as previously described in many papers. The cells also showed MR HA of sheep erythrocytes, which was potently inhibited by Forssman, and weakly by P and Pk antigens. These phenomena could not be explained by the above P adhesin specificity. This adhesin was called Forssman-like adhesin. Strain IH11024 also caused MR HA of sheep erythrocytes but not of human erythrocytes. The HA was inhibited specifically by Forssman but neither by Pk nor P antigen. This adhesin was completely different from P adhesin and Forssman-like adhesin in recognition of the carbohydrate epitope. This adhesin, until now called a pseudotype of P fimbriae, was renamed Forssman adhesin.

細菌性前立腺炎の発症に関する臨床細菌学的研究

The virulence factors of E. coli in bacterial prostatitis were studied using 59 E. coli isolated from uncomplicated prostatitis. O-antigens of prostatitis-derived E. coli belonged to some specific serotypes such as 0-4, 6, 18, 22 and the haemolysin production was positive in 64.4%. With regard to the fimbriae, the majority of the strains had type 1 fimbriae (81.4%). Mannose resistant (MR) fimbriae were also positive in 59.3% and both type 1 and MR fimbriae were positive in 55.9%. Among MR strains, P-fimbriated and S-fimbriated strains were present in 25.7% and 28.6%, respectively, indicating that these two MR fimbriae were not always specific for the prostatitis-derived E. coli. Although the specific adhesion of E. coli onto the human prostatic epithelium mediated by MR-fimbriae was equivocal, that mediated by type 1 fimbriae was observed clearly. Therefore, type 1 fimbriae was thought to be one of the most significant virulence factors in the pathogenesis of prostatitis caused by E. coli.

Suitability of Colchicine and Superoxide Dismutase for the Suppression of Renal Scarring following an Infection with Bacteria Showing Mannose-Sensitive Pili

Two new strains of Serratia marcescens were constructed by the gene manipulation method from the clinical isolate US 46, which has two kinds of pili--mannose-sensitive (MS) and mannose-resistant (MR) ones--on the cell surface. After cloning the genes of the MS and MR pili, either the MS or the MR gene was transferred to the nonpiliated Escherichia coli, and MS- or MR-piliated strains were obtained. In the experimental pyelonephritis model of rats, MS- or MR-piliated bacteria were inoculated directly to the renal parenchyma, and the following results were obtained. MS-piliated rather than MR-piliated strains stimulated severe scarring of the kidney, and this scarring was suppressed by treatment with colchicine or superoxide dismutase (SOD) during an early stage of the infection. These findings suggest that MS-piliated bacteria stimulated polymorphonuclear leukocytes, which released large amounts of superoxide resulting in renal scarring. SOD was hoped to be a drug capable of preventing renal scarring, and such a result was successfully obtained.

Characterization of Escherichia coli strains isolated from urine of secretors and non-secretors

Strains of Escherichia coli isolated from urine of secretors (242) and non-secretors (121) were compared for their serotype and their ability to express mannose-sensitive (MS) haemagglutinins and mannose-resistant (MR) haemagglutinins and to produce haemolysin. The results of the survey refuted our hypothesis that strains with characteristics associated with virulence, those with MR haemagglutinins and/or haemolysins, would be isolated more frequently from non-secretors. MR haemagglutinins were detected among 36.4% of isolates from secretors and 27.3% of isolates from non-secretors. Haemolysin production was detected among 19.8% of isolates from secretors and 12.5% of isolates from non-secretors. Both MR haemagglutinins and haemolysin were detected only on 12.4% of strains from secretors and 6.7% of strains from non-secretors.

Cloning and sequence of the gene encoding the major structural component of mannose-resistant fimbriae of Serratia marcescens

Serratia marcescens US46, a human urinary tract isolate, exhibits mannose-resistant hemagglutination and agglutinates yeast cells, thereby indicating that it has two types of adhesins. We constructed a cosmid library for the DNA of this organism and isolated DNA clones carrying genes for mannose-sensitive (MS) and mannose-resistant (MR) fimbriae. On introduction of the cloned genes into Escherichia coli K-12, MS and MR fimbriae were formed. These fimbriae were functionally and morphologically indistinguishable from those of S. marcescens. Subcloning of these gene clusters revealed that the genes encoding MS fimbriae reside on a 9-kilobase (kb) DNA fragment, while those encoding MR fimbriae are present on a 12-kb fragment. Transposon insertion and maxicell analyses revealed that formation of MR fimbriae is controlled by several genes which reside on the 9-kb fragment. The nucleotide sequence of smfA, the gene encoding the major structural component of MR fimbriae, revealed that this gene encodes a 174-amino-acid polypeptide with a typical procaryotic signal peptide. The primary structure of the smfA product showed significant homology with the primary structure of the E. coli fimbrial subunit.

Antigenic analysis of Serratia marcescens fimbriae with monoclonal antibodies

Monoclonal antibodies (MAbs) were raised against the purified fimbriae of Serratia marcescens US46, a strain expressing three morphologically distinct fimbriae. The widths of these fimbriae were 7, 4.5, and 3 nm, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified fimbriae showed three bands with molecular weights of 21,000, 20,000, and 19,000, respectively. This strain had mannose-resistant (MR) hemagglutinating activity and was agglutinated by yeast cells. Therefore, strain US46 appeared to have both MR and mannose-sensitive fimbriae. In the immunoblot analysis, all MAbs reacted with the 20,000-molecular-weight subunit when given a choice of three differently sized subunits. Immunoelectron microscopy showed these MAbs attached to the MR fimbriae with the largest width (7 nm). The antigenic cross-reactivity of fimbriae was examined by an MAb-mediated agglutination test. All MR strains of S. marcescens and some mannose-sensitive strains were agglutinated by the MAbs. The serological homogeneity of MR fimbriae was confirmed by a spot test, using the crude purified fimbriae from several MR strains of S. marcescens. In other gram-negative rods, clinical isolates of Klebsiella spp. with hemagglutinating activity were agglutinated, but clinical isolates of Escherichia coli and Enterobacter spp. were not.

Haemagglutinating and Hydrophobic Properties of Corynebacterium (Eubacterium) Suis

Corynebacterium (Eubacterium) suis strains from boars and sows haemagglutinated erythrocytes of different animal species (calf, guinea pig, poultry, pig, and human). The haemaigglutination was man nose resistant (MR) and was neither inhibited by L-fucose nor D-galactose. The hydrophobicity measured by salt aggregation test (0.1–0.9 mol/1 (NH4)2SO4) and the hydrophobic interaction chromatography test (90 % retention in octyl sepharose) together with the haemagglutinating activity, indicated the presence of fimbriae on the bacteria. The haemagglutinating and hydrophobic properties were heat-sensitive (60°C for 10 min) suggestive of the presence of a protein structure. Two types of fimbria-tion were demonstrated by electron microscopy. Fetuin and glyco^ protein inhibited the haemagglutination, whereas porcine mucin was without any effect. These results indicate that branched glycoproteins might be important receptors for these fimbriae. The pathogenic aspects of C. suis are discussed, based on recent acquired knowledge of the effect of other pyelonephritogenic bacteria.

Characterization of escherichia coli wild-type strains by means of agglutination with antisera raised against cloned P-, S-, and MS-fimbriae antigens, hemagglutination, serotyping and hemolysin production

E. coli strains isolated from patients with urinary tract infections (UTI) very often possess mannose-sensitive (MS) and mannose-resistant (MR) adherence factors (fimbriae). According to their receptor specificity the mannose-resistant adhesins can be divided into several types, P, S, M and X. We have cloned the determinants of three groups of UTI E. coli adhesins, MS, P and S, and prepared specific antisera against the fimbriae antigens. 189 hemagglutination (HA+)-positive strains, 96 fecal isolates and 93 strains isolated from UTI have been tested with these specific antisera and further characterized by receptor specific HA, HA patterns and further of the "common O serogroups" 01, 02, 04, 06, 07, 08, 018, 025, 075, most prevalent in UTI, and hemolysin production. 68 (73%) of the UTI strains and 50 (52%) of the fecal isolates showed P-receptor specificity; 16 (17%) of the uropathogenic bacteria and 33 (34%) of the fecal strains exhibited S, M or X-fimbriae antigens. 24% of the P-hemagglutinating (P+) strains reacted with P (F8)-specific antiserum. In contrast, more than three quarter of the S+-strains were agglutinated by S-specific antiserum. HA-pattern VI and 018 antigen were found to be associated with P-fimbriae strains, whereas HA-pattern V and VII and the O antigens 02 (M-type), 06 and 018 (S-type) occurred most frequently in P--strains. A high percentage of P-fimbriated strains showed mannose-sensitive hemagglutination and hemolysin production.

Influence of blood group on the availability of receptors for attachment of uropathogenic Escherichia coli

Escherichia coli strains with defined receptor specificity were used as probes to analyze the individual variation in host cell receptors with respect to blood groups. The adhesins were initially characterized as mannose sensitive (MS), mannose resistant (MR), or nonagglutinating (-). The receptor specificity of the strains with MR adhesins was defined by agglutination of synthetic Gal alpha 1----4Gal beta covalently linked via a spacer arm, (CH2)2S(CH2)2CO approximately H-bovine serum albumin (BSA) to BSA-latex beads as specific for the globoseries glycolipid receptors (MR:GS). Strains with MR adhesins not reacting with Gal alpha 1----4Gal beta-BSA-latex were designated MR:nonGS. The attachment and hemagglutination of the MR:GS strains was strictly dependent on Gal alpha 1----4Gal beta-containing receptors, as shown by the absence of binding to cells from individuals of blood group P lacking these structures. Previous reports showed differences in the composition of globoseries glycolipids between erythrocytes from individuals of P1 and P2. No significant difference was found, However, in the mean adhesion to P1 and P2 epithelial cells or in the agglutination titer for P1 and P2 erythrocytes. The MR:GS receptors were equally distributed on squamous and transitional epithelial cells. In contrast, the distribution of MR:nonGS receptors was skewed. Attachment occurred mostly to squamous epithelial cells. The attachment of strains with MR:nonGS adhesins was independent of the P blood group of the cell donor. The binding ability of MR:GS and MR:nonGS adhesins appeared independent and additive. The attachment was not influenced by the ABH blood group. However, increased binding to epithelial cells from nonsecretors occurred regardless of the P blood group, suggesting a shielding of receptors by products controlled by the secretor genes. These results illustrate how individual variation in cell surface components with and without receptor activity determine the interaction of a ligand with a known receptor.

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.