Adhesion in meningococcus

The adhesive activity of 113 meningococcal strains with different invasive properties and 10 Neisseria nonpathogenic strains have been studied. Adhesive properties have been revealed in 80-82% of these strains. Meningococcal strains isolated from the nasopharynx of carriers possess high hemagglutinating activity. The percentage of cells with pili in these strain was also higher than that in meningococcal strains isolated from the liquor of patients. This shows the presence of direct correlation between the number of pili in the cells (according to the data of electron microscopy) and their activity in the hemagglutination test, which makes it possible to use this test for the determination of the adhesive capacity of meningococci, associated with the presence of pili.     

Hemagglutinating and adhesive capacities of Klebsiella and Enterobacter strains

The authors analyze the data of studies on the hemagglutinating and adhesive capacity of 290 cultures, including 118 K. pneumoniae strains and 64 E. cloacae strains isolated from sick children, as well as 59 K. pneumoniae strains and 49 E. cloacae strains isolated from healthy children. The hemagglutinating properties of the strains were determined in the hemagglutination test with fresh, formalin- and tannin-treated red blood cells, the adhesive properties were studied by light microscopy. Among K. pneumoniae and E. cloacae strains isolated in acute intestinal infections, mannose-sensitive hemagglutination and pronounced adhesive activity were prevalent in most cases. Poorly adhesive and nonadhesive strains were characteristic of K. pneumoniae and E. cloacae cultures isolated from healthy children. The strains isolated from sick and healthy children differed only by the prevalence of adhesive cultures.     

The function of Salmonella typhi at different stages in the pathogenesis of typhoid infection

The complex study of the adhesive, colicinogenic and antigenic properties of S. typhi of different origin has revealed that adhesive properties can be observed more frequently in the strains isolated from the blood and bile and are completely absent in the strains isolated from feces. S. typhi strains of various origin do not essentially differ in their sensitivity to colicins and in the capacity for their production. Among the strains isolated from feces and bile, agents in the W-form occur more frequently than among the strains isolated from the blood. Escherichia coli, isolated from typhoid patients and carriers at the moment of the persistence of S. typhi in the body, are characterized by faintly pronounced antagonistic properties, enhanced sensitivity to colicins and rather pronounced hemagglutinating activity.     

Serotypes among Neisseria meningitidis serogroups B and C strains isolated in Canada

Antisera made to prototype serogroup B strains of Neisseria meningitidis were used to serotype, by agar gel double diffusion, 262 meningococcal serogroups B and C strains isolated in Canada. The strains included 93 from patients and 169 from carriers. Serotype 2 was associated with 39 of 75 (52%) of group B strains and 14 of 18 (77.8%) of group C strains isolated from patients. The group B strains were mainly (87.2%) serotype 2b, while the majority (92.2%) of group C strains was serotype 2a. Other serotypes (including a new provisional serotype) represented 25.3 and 5.5% of groups B and C strains, respectively. The new serotype accounted for 13% of the group B strains. Approximately 23% of the strains isolated from patients were nontypable. The distribution of serotype 2, nontype 2 (other serotypes), and nontypable strains isolated from carriers was 2.1, 36.6, and 61.3%, respectively, for group B meningococci and 22.2, 29.6, and 48.25, respectively, for group C meningococci. Serotype 11 was the most prominent of the strains isolated from carriers. Approximately 7% of all the strains were multiple serotypes. Serotype 2 is an important virulence marker associated with meningococcal groups B and C disease in Canada, with serotypes 2a and 2b being markedly associated with groups C and B meningococcal disease, respectively.     

Characteristics of nonpathogenic Neisseria and Branhamella catarrhalis based on cytopathogenicity

The study of the action of 12 Neisseria species belonging to 112 strains, 6 B. catarrhalis strains and 202 meningococcal strains on the culture of continuous cell line F1 (human amniotic cells) has revealed that nonpathogenic Neisseria are essentially weaker than meningococci in their pathogenicity (expressed in terms of CPD50). Among nonpathogenic Neisseria highly cytopathogenic strains occur in 13.9% of cases, which gives grounds for considering them opportunistic bacteria. Sharply pronounced correlation between the adhesive and pathogenic properties of Neisseria has been observed. The cytopathogenic action of Neisseria is accompanied by the lesion of the chromosomal apparatus of mitotic infected cells.     

Adhesive and other properties of Vibrio cholerae tcp+ ctx- isolated from environmental objects in the Rostov region in 2002

The adhesive, hemolytic and triacylglycerol lipase activity of 4 V. cholerae ctp+ ctx- cultures, sensitive to bacteriophage ctx+, isolated from the Don and sewage water were tested. All these cultures were found to induce hemolysis of sheep red blood cells in the Greig test in 2 hours, possessed triacylglycerol lipase activity, but had no adhesive properties. By these parameters--atoxigenicity and the absence of adhesive properties--the isolated V. cholerae strains were characterized as avirulent and epidemically safe.     

Immunoproteomic identification of the hypothetical protein NMB1468 as a novel lipoprotein ubiquitous in Neisseria meningitidis with vaccine potential

Many potential vaccine candidates for serogroup B Neisseria meningitidis (NMB) have been identified by reverse vaccinology, a genome-based approach. However, some candidates may be unseen owing to uncertain annotation or their peculiar properties. In this study, we describe the preparation and identification of a novel lipoprotein expressed in all meningococcal strains tested. mAb were first prepared from mice immunized with a meningococcal B strain isolated in Taiwan. Total proteins from the immunizing strain were separated by 2-DE in duplicate. Clone 4-7-3, which crossreacted to 174 tested meningococcal isolates, was used as the primary antibody for Western blotting. The immunoreactive spot was identified by LC-mass spectrometric analysis of the corresponding spot from the silver-stained gel and confirmed by molecular biology approach to be a novel lipoprotein encoded by the hypothetical NMB1468 gene. The potential use of this protein, designated Ag473/NMB1468, as a vaccine component was evaluated using the recombinant protein produced in Escherichia coli. Immunized mice were found to be protected from developing meningococcal disease after intraperitoneal inoculation with a lethal dose of meningococcal strain Nm22209, suggesting that Ag473/NMB1468 may be a promising vaccine candidate. This study also demonstrates the usefulness of the immunoproteomic approach in identification of novel vaccine candidates.     

The adhesive properties of salmonellae in the dynamics of the infectious process

In patients with toxic infections salmonellae were identified in 31% of cases. The patients were divided into two groups: the control group receiving treatment with infusion solutions and the test group treated, in addition to the usual scheme of therapy, with indomethacin in a daily dose of 150 mg. The study revealed that salmonellae isolated at the initial stages of the disease possessed highly pronounced adhesive properties. The adhesive properties of salmonellae isolated at the stage of convalescence from the patients of the test group were considerably less pronounced than those of salmonellae isolated from the same patients at the peak of the disease. In the control group no differences in the adhesive properties of salmonellae isolated from the same patients were established.     

Typing of Neisseria meningitidis isolates from patients with invasive disease by molecular analysis of porin genes

Polymerase Chain Reaction-Restriction Fragment Length Polymorphism assay (PCR-RFLP) for porA and porB genes of Neisseria meningitidis was applied to type 64 strains isolated from cases of invasive disease in Italy. The technique was also successfully used on non-viable strains and on cerebrospinal fluid samples from patients with meningococcal meningitis diagnosed by PCR. RFLP patterns were obtained for all strains, including those nontypeable or nonsubtypeable by the serological methods. The results confirmed the usefulness of the PCR-RFLP for porA and porB genes of Neisseria meningitidis in differentiating strains belonging to the same serological type and provided discriminative patterns in the increased proportion of non serotypeable/serosubtypeable strains circulating in Italy in recent years.     

Factors influencing the adhesive properties of Pseudomonas aeruginosa

The aim of this study was to evaluate different factors which may influence surface and adhesive properties of Pseudomonas aeruginosa strains isolated from patients with urinary tract infections. P. aeruginosa strains exhibited moderate surface hydrophobicity as shown by "salting out" with ammonium sulfate and hydrophobic interaction chromatography. The ability to haemagglutinate red blood cells by P. aeruginosa strains was increased when the cells were treated with papain and neuraminidase. The ability of all tested strains to attach to plastic and glass surfaces was independent on incubation temperature. There was no significant difference in the ability of any particular P. aeruginosa strains to adhere to Vero cells in culture. In this study no correlation between hydrophobic properties, intensity of haemagglutination, and ability to attach to Vero cells in culture was observed.     

Comparative characteristics of the adhesive properties of microorganisms isolated from the urine of children with chronic obstructive pyelonephritis

The adhesive properties of 215 cultures, including 215 Escherichia coli strains, 43 Klebsiella pneumoniae strains and 60 Pseudomonas aeruginosa strains isolated from the urine of 124 children with chronic obstructive pyelonephritis were studied in the direct hemagglutination test simultaneously with those of 30 E. coli strains and 20 K. pneumoniae strains isolated from the feces of 50 healthy children, as well as 60 P. aeruginosa strains isolated from children with parenteral infections of other localization. E. coli and K. pneumoniae strains isolated from the urine of children with chronic obstructive pyelonephritis were found to have D-mannose-resistant hemagglutinins (68% and 37.2%) and a combination of mannose-sensitive and mannose-resistant adhesins (44.6% and 13.3% respectively). P. aeruginosa strains isolated from the urine of urological patients in the postoperative period showed the presence of mannose-resistant hemagglutinins to a greater extent (76.6%) than those isolated from children with parenteral infections of other localization (45%).     

A comparison of three methods for assaying hydrophobicity of pathogenic vibrios

The surface hydrophobicity of strains of Vibrio alginolyticus, V. carchariae, V. damsela, V. harveyi and V. vulnificus , isolated from either diseased cultured grouper ( Epinephelus malabaricus ) or penaeids ( Penaeus monodon and P. japonicus ) was determined using three different methods:the salt aggregation test (SAT), bacterial adhesion to hydrocarbons test (BATH), and adherence to nitrocellulose filters test (NCF). The results obtained indicate that all the strains tested showed some degree of hydrophobicity with the type strain of V. harveyi (ATCC 25919) showing strong hydrophobic properties in all the methods. The SAT method used in the present study was modified to a microtitre tray test, an easier test to read than the conventional in glass slide methodology. All the 13 test strains were positive in the BATH test when n -octane was used as the solvent, but only one strain was positive when n -hexadecane was used as the solvent. It is suggested that this method using n -octane as solvent is suitable for assaying the hydrophobicity of pathogenic vibrios isolated from diseased aquatic animals.     

Adhesion of Corynebacterium diphtheriae

The conditions for the direct hemagglutination test performed to determine the degree of adhesion of C. diphtheriae were defined. For this test sheep red blood cells, trypsin-treated ex tempore, were used. Only newly isolated cultures, subcultured for not more than 2-5 times and stored for not more than 2-7 days or freeze-dried, were employed. The culture to be tested was grown in nutrient agar with 10% of normal horse serum. The test was made in microtitrator round-bottom wells. The mixture of different dilutions of the culture was incubated for 2 hours at 37 degrees C, then left overnight at 4 degrees C. All 147 newly isolated or freeze-dried C. diphtheriae strains under test had different degrees of adhesion. Their adhesive activity was unrelated to their biovar. Toxigenic strains were significantly more active in hemagglutination (53.5 +/- 3.0%) than nontoxigenic ones (23.5 +/- 3.9%). The strains isolated from the nose, irrespective of their biological properties, were more active than those isolated from the pharynx.     

Characterization of Neisseria meningitidis strains isolated from carriers

Neisseria meningitidis carriers strains were isolated from 17-19 teenagers (n = 14) and recruits (n = 267). The longitudinal study comprises three meningococcal carriage trials performed on healthy young men during two--six months of their service in Polish military units. Altogether 54, 124 and 89 meningococcal strains were obtained during spring 1998 and autumn 1998, 1999 trials. Sixty two percent of meningococcal carrier strains were non-groupable, however among the remaining strains, serogroup B was predominant (29.5%). During spring 1998 and autumn 1999 trials the predominant phenotypes were N. meningitidis NG:21:P1.7, but during the autumn 1998 NG:21:P1.7 or NG:NT:P1.5. Ribotyping of type 21 and/or subtype P1.7 strains (n = 27) showed presence of 2 main ribotypes. Pulsed Field Gel Electrophoresis of consecutive isolates recovered from the same carrier showed great similarity of the patterns.     

Proteus adhesion to intestinal epithelium

The adhesive properties of Proteus strains isolated from different sources have been studied under conditions similar to the real interaction of microorganisms with the epithelial cells of intestine. A comparison of the adhesive properties of Proteus and of colon Bacillus has shown that the value of the strong adhesion to the mucosa of Proteus isolated under enterocolitis at the same bulk concentrations of the infectious suspension is 2-3 order less than that of E. coli. The adhesion of Proteus to the surface of epithelial cells begins at bulk concentrations exceeding those for the colon Bacillus by 3-4 orders. Besides, a toxic effect of number of freshly isolated Proteus strains on the epithelial cells of intestine mucosa is observed. Strains isolated from patients with diarrhea and from environment differed from each other in the studied criteria. A conclusion is drawn that at the initial stage of the interaction with the intestine mucosa the Proteus strains differ considerably from the indigenous strain of the colon Bacillus in the ability to colonize the epithelial surface.     

Extracellular slime production and adhesion of Morganella morganii strains to polystyrene

The aim of this study was the evaluation of the ability of extracellular slime production and adhesive properties of M. morganii strains. This study included 50 of M. morganii strains isolated from clinical samples. All of these strains were isolated in the Clinical Microbiology Department of dr. A. Jurasz University Hospital in 2008-2009. Five (10.0%) out of 50. M. morganii strains demonstrated extracellular slime production. Adherence to polystyrene revealed 36 (72.0%) of M. morganii strains in it 6 strains (12.0%) adhered strongly, medium - 12 (24.0%) and weakly - 18 (36.0%).     

The adherence of lactic acid bacteria to the columnar epithelial cells of pigs and calves

The adhesion of various lactobacilli and streptococci to columnar epithelial cells of pigs and calves were studied, by in vitro methods. The porcine strains isolated most frequently were Lactobacillus delbrueckii, Lact. acidophilus and Lact. fermentum. Thirteen of the 22 lactobacilli were adhesive. All the streptococci isolated belonged to Lancefield's D-group; none of them adhered to pig epithelial cells. The adhesive strains (9 of 22) of calves were identified as Lact. fermentum. Adherence was variable even between strains of the same species. Isolates from plant material, cultured milk and cheese did not adhere to the columnar epithelial cells in vitro. The adhesive porcine strains tolerated low pH and bile acids, which is important for their survival under conditions in the stomach and intestine.     

Antibiotic sensitivity and pathogenetic factors of hospital strains of Pseudomonas aeruginosa isolated from patients treated in a resuscitation unit]

Strains of Pseudomonas aeruginosa were isolated from patients treated in the Centre of Thermal Affections in 1985-1989. It was shown that 72.9, 59.3, 33.8 and 54.2 per cent of the isolates were sensitive to cefotaxime, tobramycin, gentamicin and polymyxin, respectively. The study of pathogenicity factors of the isolates revealed that 83 per cent of the strains produced thermolabile enterotoxin, 79.6 per cent of the strains had adhesive activity and 71.1 per cent of the strains produced hemolysin. The study detected combinations of various pathogenicity factors. 42.3 per cent of the isolates had both adhesive and enterotoxigenic properties. Adhesiveness and hemolytic activity were shown by 13.5 per cent of the strains. 16.9 per cent of the strains produced both enterotoxin and hemolysin. Adhesive activity, enterotoxigenicity and hemolysin production were observed in 6.7 per cent of the strains. It was noted that the strains of P. aeruginosa resistant to polymyxin mainly produced enterotoxin (18.6 per cent) and those resistant to cefotaxime had adhesive activity (34.0 per cent).     

The drug sensitivity of meningococci and the characteristics of its determination

The results obtained in the study of antibiotic and sulfamide sensitivity of 197 Neisseria meningitidis strains of groups A, B and C, isolated from the spinal fluid and blood of patients with meningococcal infection hospitalized in the 2nd Clinico-Infectious Hospital, Moscow, in 1984-1989 and studied with the use of the disc diffusion method and the method of serial dilutions of antibiotics in solid culture media, are presented. As revealed in this study, N. meningitidis strains retained their high sensitivity to penicillin and ampicillin (MIC50 = 0.016 and 0.032 micrograms/ml respectively). Sensitivity to tetracycline decreased (MIC50 = 0.5 micrograms/ml) and to rifampicin increased (MIC50 = 0.063 micrograms/ml). 48.5% of strains were resistant to streptomycin. In recent years the proportion of N. meningitidis, resistant to sulfanilamide preparations, significantly decreased and MIC50 was equal to 2.5 micrograms/ml in comparison with 5-10 micrograms/ml in the preceding period. The results of testing sensitivity to antibiotics by both methods coincided. Still the disc diffusion method can be used in epidemiological surveillance on meningococcal infection, while for more exact differentiation of N. meningitidis strains the use of the method of serial dilutions is necessary.     

Lessons from meningococcal carriage studies

Neisseria meningitidis, an obligate commensal of humans, normally colonizes the mucosa of the upper respiratory tract without affecting the host, a phenomenon known as carriage. In Europe, as much as 35% of young adults are carriers at a given time. Recent studies using molecular methods for clone identification have demonstrated the extensive genetic diversity of the strains isolated from carriers, in comparison with a limited number of hypervirulent strains associated with invasive disease. Published studies and new data generated through the framework of the EU-MenNet clearly indicated significant differences in pathogenicity between meningococcal clones and in the distribution of multilocus sequence types among isolates from asymptomatic carriers among European countries; simultaneous carriage of more than one meningococcal strain in the throat is rare, but occasionally occurs; and the commensal association of particular clones with a host is a long-term relationship, often lasting several months. Further investigations of the carrier state are warranted to improve our understanding of the epidemiology and pathogenesis of meningococcal disease, as well as to support the introduction and to measure the impact of mass vaccination.