Medycyna doswiadczalna i mikrobiologia最新文献

Introduction: Tularemia is a highly infectious zoonotic disease caused by Gram-negative bacterium Francisella tularensis. The microbiological diagnosis of tularemia is based on bacteriological, molecular and serological investigations. In the present study we compared of usefulness of commercial ELISA Virion/Serion, home-made ELISA and tube agglutination test in serodiagnosis of tularemia.

Methods: Serum samples from 57 patients with clinical symptoms of tularemia, 13 patients with yersiniosis and 20 blood donors were tested. The cut-off limit of IgA, IgG and IgM serum antibodies in home-made ELISA was set at mean antibody titer determined in sera of healthy blood donors exceeded by the three standard deviations. The cut-off for positivity in tube agglutination test was titers 25. The IgG and IgM antibodies to lipopolysaccharides of F. tularensis in Virion/Serion ELISA were measured and results interpreted according to the instructions by the manufacturer.

Results: The results of the study showed that 39 (68.4%) serum samples obtained from the patients suspected for tularemia were positive by tube agglutination test and Virion/Serion ELISA assay for IgG and IgM antibodies. Home-made ELISA was slightly more sensitive and detected the IgA/IgG antibodies in 42 (73.7%) and IgM antibodies in 39 (68.4%) of serum samples. The positive reactions were not detected by the tube agglutination test and home-made ELISA in serum samples from patients with yersiniosis and blood donors. The Virion/Serion ELISA detected IgG antibodies in diagnostically significant level only in one blood donor.

Conclusions: In conclusion, all three serological tests can be successfully used in routine serodiagnosis of tularemia.

Introduction: During the past 20 years, several studies at a national level in different countries followed resistance trends for Bacteroides sp. and Clostridium difficile. This study analysed antimicrobial susceptibility 73 anaerobic bacteria strains of Bacteroides fragilis group (BFG) and C. difficile to fluoroquinolones and other antimicrobial drugs.

Methods: The strictly anaerobes strains isolated in different hospitals were sent to the Department of Medical Microbiology, Medical Uniwersity of Warsaw, where species determination was carried out with the API20 ANA (bioMerieux SA, Marcy-l'Etoile, France) system. Susceptibility to antimicrobials was determined using E-test.

Results: The rates of high resistance to ciprofloxacin and moxifloxacin of BFG was respectively 84% and 31% and among of C. difficile strains respectively 92% and 36%). The percentage of BFG strains resistant to erythromycin and clindamycin were respectively 84% and 46%. The percentage of C. difficile strains resistant to erythromycin and clindamycin was 52%. Reduced level of susceptibility of BFG strains to amoxicillin/clavulanic acid (8%) was confirmed. Resistance to cefoxitin was 16% of BFG strains. All tested strains as well as BFG and C. difficile were susceptible to metronidazole. Was observed reduced leve (EUCAST) of susceptibility of C. difficile strains to vancomycin (13%). CONCLUSIONS. Increasing resistance to various antimicrobial agents is a significant problem in Poland. This demonstrate the need to continue with antibiotic resistance testing and surveys in anaerobic bacteria.

Introduction: In presented study we investigated the effect of multiple freeze-thaw cycles of human sera on the determination of IgA, IgG and IgM antibodies to selected bacterial antigens.

Methods: A panel of 15 serum samples with elevated levels of antibodies to Mycoplasma peumoniae, Yersinia enterocolitica and Salmonella spp. were used (5 positive sera for each pathogen). One set of aliquots designed as the baseline, was taken and stored at 4-8o C for the remainder for the study. The remaining seven sets of aliquots were divided into two parts and repeatedly frozen respectively at two different temperatures: -65 degrees C and -25 degrees C. Once a day the aliquot sets were removed from the freezer and allowed to stand at room temperature for approximately 1 h until completely thawed. For the determination of the level of antibodies the sera after: 2, 5, 10, 15, 20, 25 and 30 freeze/cycle were used. The measurement of IgA, IgG and IgM antibodies was done using a home-made ELISA with four different antigens: whole-cell antigen of M. pneumoniae FH strain, LPS and Yop antigens of Y. enterocolitica serotype O:3 and LPS extracted by Westphal method from Salmonella serogroup B +D. The results were presented as the arithmetic mean of the antibody titre in five sera which were treated by the same number of freeze-thaw cycles.

Results: There was no significant statistic difference between levels of antibodies in unfrozen and frozen sera even after 30 freeze-thaw cycles. Depending of the antigen used in ELISA a slight varations in the level of antibodies were observed but the changes were small and not clinically significant. Examination of the ELISA values does not suggest any consistent nonlinear trend in levels of IgA, IgG and IgM antibodies in sera frozen at -65 degrees C as well at -25 degrees C.

Conclusions: Our study demonstrates that the IgA, IgG and IgM antibody activity levels measured for M. pneumoniae, Y enterocolitica and Salmonella antigens are stable even after 30 freeze-thaw cycles.

Introduction: The aim of this study was to investigate the antibacterial properties of oregano (Origanum heracleoticum L.) essential oil against clinical strains of Escherichia coli and Pseudomonas aeruginosa. The antibacterial activity of oregano essential oil was investigate against 2 tested and 20 clinical bacterial strains of Escherichia coli and 20 clinical strains o Pseudomonas aeruginosa come from patients with different clinical conditions.

Methods: The agar dilution method was used for microbial growth inhibition at various concentrations ofoil. Susceptibility testing to antibiotics was carried out using disc-diffusion method.

Results: The results of experiments showed that the tested oil was active against all of the clinical strains from both genus of bacteria, but strains of Escherichia coli were more sensitive to tested oil. Essential oil from Origanum heracleoticum L. inhibited the growth of Escherichia coli and Pseudomonas aeruginosa clinical strains with different patters of resistance.

Conclusions: The obtained outcomes will enable further investigations using oregano essential oil obtained from Origanum heracleoticum L. as alternative antibacterial remedies enhancing healing process in bacterial infections and as an effective means for the prevention of antibiotic-resistant strain development.

Introduction: The aim of this study was to estimate the contribution strictly anaerobic bacteria in the etiology of infections in patients on surgery and orthopedic wards.

Methods: We examined 159 samples taken from patients hospitalized in surgical wards and 179 clinical specimens taken from orthopedic patients. Clinical strains of obligate anaerobes were identified by API 20A biochemical tests (ATB Expression, bioMerieux S.A., France). Susceptibility of the clinical strains was examined by ATB ANA (bioMerieux S.A., France) system. The MIC values were determined by the gradient diffusion method, Etest (AB BIODISK, Sweden i bioMerieux S.A., France).

Results: Gram-negative bacteria predominant in the samples taken from surgical patients, Most frequently we isolated rods of the genus Bacteroides (26%): B. fragilis, B. ovatus/B. thetaiotaomicron, and B. distasonis. In 44 samples (28%) we identified only anaerobic bacteria. Multibacterial isolations, with the participation of anaerobic and aerobic flora, dominated among patients in the study. Overall 238 strictly anaerobic bacteria were cultured from patients hospitalized in orthopedic wards. Gram-positive bacteria accounted for 78%. The most frequently were isolated Peptostreptococcus (56%), Propionibacterium (10%) species. In this study all Bacteroides strains were resistant to penicillin G. Some species were resistant to clindamycin, as well. Overall 40% of Bacteroides strains taken from surgical and 50% isolated from orthopedic wards showed no sensitivity to this antibiotic. A similar phenomenon was observed among bacteria of the genus Prevotella.

Conclusions: In samples taken from orthopedic patients we observed the predominance of Gram-positive anaerobic bacteria. Some of them were part of the normal flora but they should not be excluded as an etiology agents of infection. The specimens taken from patients treated in surgical wards showed the presence of a mixed microflora, which included aerobic and anaerobic bacteria, primarily Gram-negative rods. Rational empirical therapy of infections with anaerobes should be mainly based on the resistance pattern in each ward and hospital. In view of the increasing in the number of resistant strains is necessary to monitor drug resistance of anaerobic bacteria.

Introduction: Fluoroquinolone are broad-spectrum antimicrobial agents extensively used by physicians. This widespread use has been associated with increased level ofquinolone resistance strains, particularly in Enterobacteriaceae. Plasmid-mediated quinolone resistance (PMQR) including Qnr determinants with the potential for horizontal transfer confer to quinolone resistance. Plasmid harboring qnr genes may also encode extended-spectrum beta-lactamases (ESBLs) such as CTX-M, SHV and TEM type. The prevalence ofplasmid-mediated quinolone resistance (PMQR) determinants like qnrA, qnrB and qnrS was investigated in a collection of 215 Enterobacteriaceae strains with reduced susceptibility to fluoroquinolone.

Methods: The isolates (n=215) were collected from 1 March to 31 September, 2010 in a regular hospital in Warsaw, Poland. The resistance to nalidixic acid, norfloxacin and ciprofloxacin was determinated by twofold agar dilution method, while MICs of moxifloxacin were examined by using E-test. The prevalence of qnrA, qnrB, qnrS, blaCTX-M, blaSHV and blaiTEM was evaluated by PCR. All PCR-products for qnr were sequenced. The epidemiological relationship between positive isolates was studied by PFGE method.

Results: Eighteen isolates (8,3%) carried the qnr gene encoding the QnrA, QnrB or QnrS. The coexistence of both qnrA and qnrS genes was noted in one isolate of E. coli. The qnrB gene was the most common qnr type found. All the Qnr-producing strains were simultaneously resistant to naldixic acid and different - level non-susceptible fluoroquinolone (MIC CIP 1.5-1024 microg/ml). Most of qnr-positive strains (88.9%) were extended-spectrum beta-lactamase (ESBL) producers of CTX-M and TEM types predominantly.

Conclusions: The present study highlights the wide spread of Qnr-like determinants in clinical Enterobacteriaceae non-susceptible to fluoroquinolone in Poland, with an association with the ESBL.

The past decade has witnessed a significant expansion of knowledge in field of Y. enterocolitica pathogenicity and virulence. In this period, a change of high-pathogenicity Y. enterocolitica bioserotype 1B/O8 geographical distribution has been observed. In 2003, Y. enterocolitica 1B/O8, major representative ofAmerican lineage, emerged in Europe, where it prevails in Poland. Complete genomes of major pathogenic bioserotypes have been made available, triggering substantial advances in genotyping and phylogeny of Y. enterocolitica. This study attempts to bring together the novelty in field of Y. enterocolitica pathogenicity and molecular epidemiology to rise the interest in the field, and to encourage further studies to better understand epidemiology ofyersiniosis in Poland.

Introduction: The increase of measles incidence in Poland was recently observed. Furthermore, the analysis of routine serological tests performed in the department of virology, NIPH-NIH revealed, that nearly half of young people (20-30 years old) have no antibodies against measles virus. The paper presents results of IgG specific for measles virus prevalence in the sera of vaccinated and unvaccinated subjects, which aimed to make the selection of groups for immunological memory research.

Methods: Total of 100 persons were examined based on results of determination of the presence of IgG anti-MeV: 26 people born before and 74 born after 1972 year. From this group, 55 participants were selected for further study and divided into 3 groups (1) subjects born before 1972, unvaccinated against measles and seropositive as a result of natural infection, (2) subjects born after 1972, vaccinated against measles but seronegative or with traces ofanti-MeV IgG presence, (3) subjects born after 1972 seropositive due to vaccination. Selected persons are subject to further examinations include determination the number of leukocytes and lymphocytes profile.

Results: The level of anty-MeV IgG antibodies in subjects after natural infection was significantly higher compared to levels obtained by vaccinations. No significant differences in the immunological parameters which could influence on immune response were observed.

Conclusions: Obtained results lead to search other factors that may affect the weak postvaccinal humoral response.

Introduction: Mobil genetic elements are pivotal in the dissemination and persistence of antimicrobial resistance in enterococci. This study investigated the presence of plasmids amongst E. faecium as well as other species of this bacteria.

Methods: Bacterial strains were identified as described previously. Plasmid DNA isolation and digestion with restriction endonucleases were described. The fragments ofplasmid DNA were separated by electrophoresis.

Results: Most of the isolates had multiple plasmids, particularly the E. faecium strains. The same plasmid were observed in the same species of enterococci as well as in the other. Plasmid patterns suggested that some of the E. faecium strains were shared between wards.

Conclusions: The occurrence of several unrelated strains with the same plasmids may indicate horizontal spread of genetic elements.

Introduction: The genus Streptococcus comprises a number of species characterized by a differential pathogenic potential. These bacteria can be considered as members of microbial physiological flora but they can also cause mild infections or severe, life threatening conditions. The majority of infections of streptococcal etiology are caused by beta-hemolysing species. The predominant causative agent of bacterial pharyngitis is Streptococcus pyogenes. This species usually doesn't give rise to any identification difficulties due to the introduction the well determined diagnostic schemes. Problems concerning laboratory identification can be, however, associated with other species of beta-hemolysing streptococci isolated from patients with pharyngitis. These streptococci can demonstrate features similar to those of S. pyogenes and share the group antygen A, such as some strains of Streptococcus anginosus and Streptococcus dysgalactiae subsp. equisimilis. The determination of sensitivity to bacitracin, which is a feature typical of S. pyogenes, is the basic test useful for its preliminary identification. Nevertheless, the identification of some strains by this test can give rise to incompatibility. The aim of the study was characterisation of beta-hemolysing streptococci resistant to bacitracin isolated from patients with pharyngitis. The examined bacterial strains caused identification problems by the use of routine diagnostic methods.

Methods: The material included 14 streptococcal strains resistant to bacitracin which were isolated from adult patients suffering from pharyngitis. The bacteria were cultured on media dedicated for the species. The following routine diagnostic tests were used for the bacterial identification: sensitivity to bacitracin (0.04 U/disc), CAMP test, determination of the group antigens A, B, C, D, F and G (Slidex Strepto-Kit), and determination of biochemical features by the API 20 STREP test (bioMèrieux). The sensitivity of streptococcal isolates to antibiotics (penicillin, clindamycin, erythromycin, tetracycline, vancomycin, ofloxacin) and trimethoprim/sulfamethoxazole, was determined by the disc diffusion method on the Mueller-Hinton agar with 5% sheep blood (the inoculum-0.5 McFarland).

Results: Among the 14 isolates resistant to bacitracin, 6 isolates of S. pyogenes, 6 isolates of S. constellatus, and 2 isolates of S. dysgalactiae subsp. equisimilis were identified. All isolates were sensitive to penicillin and vancomycin. One isolate ofS. pyogenes demonstrated constitutive MLSB resistance mechanism. Seven isolates were resistant to tetracycline: S. dysgalactiae subsp. equisimilis (3 isolates), S. constellatus (3), and S. pyogenes (1). The number of isolates resistant to trimethoprim/sulfamethoxazole was as follows: S. pyogenes (6) and S. dysgalactiae subsp. equisimilis (1), whereas four isolates were resistant to ofloxacin.

Conclusions: