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Introduction: Adhesion of pathogenic bacteria to host cells is a crucial step during infection. The presence of specific adhesion factors on the bacterial cell surface determines the tropism of the pathogen to the tissues expressing certain surface receptors. The adhesion is mediated primarily by filamentous structures called pili. Three distinct pilus structures can be produced by Corynebacterium diphtheriae: SpaA-, SpaD- and SpaH-type pili. Pilus genes encode a total of nine pilus proteins, named SpaA through SpaI, and six sortases, named SrtA through SrtF. All the pilus genes are located on pathogenicity islands and can be acquired and lost by different strains. The aim of presented studies was assessment of occurence of pili genes among C. diphtheriae strains isolated from different infections, including invasive infections, in Poland., Methods: Thirty-one toxigenic and nontoxigenic C. diphtheriae strains isolated from wounds, blood, nose and pharynx were investigated for presence of 15 pili genes. The studies were conducted using PCR. Gene specific primers were designed on the basis of the complete genome sequence of C. diphtheriae NCTC 13129., Result: All the nontoxigenic C. diphtheriae strains isolated from invasive infections possess every tested genes in contrast to toxigenic strains that revealed highly mosaic structure of pili gene clusters. Differences in gene content were detected in SpaA- and SpaH-type pili gene clusters. Complete set of genes in SpaD-type pili gene cluster was detected in all but two strains. The two strains did not possess any of SpaD-type pili genes., Conclusions: Invasiveness of C. diphtheriae strains could be related to adhesive factors. Results of our studies suggest that ability to express all types of pili is indispensable for causing invasive infections by nontoxigenic C. diphtheriae. Whereas full set ofpili genes is not necessary for causing classical diphtheria.

Introduction: Mycoplasma pneumoniae is a common etiologic agent of community-acquired respiratory infection. In serological diagnosis of M. pneumoniae infections tests have been described based on the purified P1 protein, which is the most important virulence factor of this pathogen, as antigen. The aim of his study was to express and purify a recombinant protein P1 M. pneumoniae and next evaluate this protein as high specific antigen in serodiagnosis of mycoplasmosis., Methods: Protein P1 M pneumoniae was expressing in E. coli BL21 (DE3) using the pET-30 Ek/LIC expression vector. Based on published literature, we decided to express C-terminal region [P1-C1] encompassing amino acid residues 1160 to 1521. Purification was accomplished by immobilized metal (Ni2+) affinity column chromatography (His-trap). Serum samples collected from 221 patients with mycoplasmosis, positive in complement fixation test (CFT), 87 patients with other then mycoplasmosis bacterial infections and 80 blood donors were screened for anti-P1 recombinant protein IgA, IgG and IgM antibodies by using the home-made ELISA., Results: SDS-PAGE and Coomassie brilliant blue staining confirmed a high purity of the recombinant P1 protein preparation with an expected molecular mass of 39,7 kDa. The specificity of the recombinant protein was confirmed by western blot analysis using serum samples from rabbits immunized by M pneumoniae. The results of ELISA revealed that more then 70.0% of patients with mycoplasmosis confirmed by CFT, had antibodies to recombinant P1 protein in diagnostically significant level (x + 2SD). The antibodies were found only sporadically in sera obtained from patients with other then mycoplasmosis bacterial infections and clinically healthy persons. A comparison of results obtained in home-made ELISA with results of commercial western blot (Virotech) showed similar, ranged from 84.2% to 97.4%, compatible of results. The IgM antibodies to recombinant P1 protein were found in 87.2% sera obtained in acute phase of disease, in 80.0% sera obtained 2-4 weeks after onset of clinical symptoms and only in 43.8% sera obtained in chronic mycoplasmosis., Conclusions: The present study confirmed the earlier observations of the high usefulness of recombinant P1 protein for reliable serologic diagnosis of M. pneumoniae infection.

Close contacts between children attending day-care centres, orphanages or similar institutions favours mutual transmission of infections with nontypeable H. influenzae (NTHi) strains. NTHi are transmitted via air-droplets or via direct contact with respiratory system exudates from nonsymptomatic carriers. The study aimed at monitoring of potentially invasive nontypeable H. influenzae strains of hmwA+ profile among children in day-care centres and orphanages. Monitoring of prevalence of strains of hmwA profile in a single day-care centres within 8 months confirmed high level of NTHi strains transmission including NTHi strains potentially invasive. It has been shown, that potentially invasive NTHi strains appear with different frequency in day-care centres and orphanages. It also points out that dissemination NTHi is easy in such an environment.

The study was based on hypothesis that in the nontypeable population of H. influenzae strains isolated from children there are some genetically predisposed to induce symptomatic infection in children and that they might be divided into different groups depending on profiles of genes encoding main adhesins synthesis. The work aimed at analysis of distribution of genes encoding adhesins and evaluation of domination possibility of some strains representing particular adhesins genes profiles among NTHi population. Results of the study revealed that among population of NTHi strains, distribution of genes encoding main adhesins are differing. Among children, NTHi strains harbouring genes encoding HA and HMW1/HMW2 adhesins were more prevalent in healthy children and in children with symptomatic infections, respectively. Analysis of strains harbouring main adhesins profiles might be a useful screening method in monitoring strains circulating among children, in order to determine the most invasive NTHi strains.

Sixty fenotypically coagulase-negative Staphylococcus aureus strains were screened for the presence of six adhesion genes. The strains were isolated from varied clinical samples and varied patients in 16 medical centers, in majority from the region of Gdansk. Multiplex PCR in two primer sets was used for detection of the following genes: bbp (bone binding protein), cna (collagen binding protein), ebp (elastin binding protein)and fnbB (fibronectin B binding protein), fib (fibrinogen bindng protein) and clfA (clunmping factor A). More than half (57%) of the examined population harbored four genes: fnbB,fib, cna i clfA. All of the strains were found to be clfA positive and 90% of them were positive for fnbB, 90% for fib and 67% for cna. All of these genes were significantly more common in MRSA than in MSSA. The particular genes were occurred in strains derived from varied clinical samples.

The aim of study was the molecular characteristic of S. aureus and S. epidermidis isolates obtained from skin surface, wounds, deep tissues of hospitalized patients and from skin surface of non-hospitalized patients. Genes encoding virulence factors were examined using PCR reaction and specific primers. Genes encoding adhesinsfnbA and cna and gene eta for epidermolytic toxin were mostly present in S. aureus isolates coming from wounds and deep tissues compared to these from skin surface. Gene atlE encoding autolysin of S. epidermidis was detected in all studied isolates, whereas gene icaAB was present in almost all isolates. Comparison of results obtained by PCR and conventional method of the resistance to methicillin estimation showed discrepances suggesting the need for using of both methods in some clinically difficult cases of S. aureus infection.