[Investigation of Streptococcus pyogenes virulence factors and typing by multiple locus variable number tandem repeat fingerprinting (MLVF) method]

Streptococcus pyogenes is an important bacterial pathogen that colonizes the throat and skin of human beings and causes a wide variety of diseases ranging from mild infections like pharyngitis, tonsillitis and impetigo to severe invasive infections such streptococcal toxic shock syndrome, septicemia, and necrotizing fasciitis, and produces a wide variety of virulence factors. The aim of this study was to investigate the antibiotic resistance, virulence genes; [pyrogenic exotoxin genes (speA, C, G, H, I, J, K, L, M, smeZ and ssa), deoxyribonuclease genes (sdaB, spd3, sdc ve sdaD), protease genes (speB, spyCEP ve scpA) and inhibitor genes (mac and sic)] of S.pyogenes strains isolated from throat cultures of patients with symptomatic tonsillo-pharyngitis and typing by multiple locus variable number tandem repeat fingerprinting (MLVF) method. One hundred and fifty S.pyogenes isolates were identified by conventional methods and streptococcus group A latex kit (Biomerieux, France). Antibiotic susceptibility tests were performed by Kirby-Bauer disk diffusion method as recommended by Clinical and Laboratory Standards Institute. DNA isolation was performed by using a commercial DNA isolation kit (Qiagen, Germany) in accordance with manufacturer's recommendations. The virulence genes were determined by multiplex PCR. MLVF method was performed with multiplex PCR using specific primers for repeated sequences within bacterial genome. All of the S.pyogenes isolates were susceptible to penicillin G, cefotaxime, ceftriaxone, chloramphenicol, clindamycin, erythromycin, levofloxacin, vancomycin and linezolid. Among streptococcal pyrogenic exotoxin genes the most frequent gene was smeZ (90.0%) followed by speG (88.0%), speC (58.7%), ssa (42.7%), speA (33.3%), speJ (24.0%), speK (18.7%), speH (14.0%), speI (13.3%), speL and speM (9.3%). Of the DNase genes, sdaB was detected in all strains (100%), spd3, sdc, sdaD genes were determined as 64.7%, 36.0%, 24.7% respectively. Protease genes (speB, spyCEP, scpA) and mac gene from the inhibitor genes were positive in all strains, and sic gene was positive in only 3 (2.0%) of the isolates. Thirty-two different patterns that contained two or more isolates were determined by MLVF analysis. Ninety one isolates were included in any of the 32 different patterns, while 59 isolates were defined as sporadic isolates. In conclusion, S.pyogenes isolates collected from throat cultures of patients with symptomatic tonsillo-pharyngitis in Konya/Turkey were susceptible to all antibiotics studied and have carried a very high rate of virulence factors. However the isolates were mostly clonally unrelated and sporadic. This study is the first report in Turkey, in which S.pyogenes isolates were typed by the MLVF method and a large number of virulence factors were investigated.

The seroprevalence of both hepatitis B and hepatitis C at the first-step health organizations and the difference between the urban and rural areas

BACKGROUND

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are very important infectious agents for public health. The aim of this retrospective study was to assess the seroprevalence of hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs) and anti-HCV test results of patients who admitted to first-step health organizations in central and peripheral districts of Konya, the central region of Turkey during the period 2005-2010.

METHODS

In this study, HBsAg, anti-HBs and anti-HCV screening test results of patients who admitted to first-step health organizations in Konya during the period 2005-2010 were retrospectively investigated from the laboratory records. This study was approved by the Konya Health Directorate. All screening tests were performed on the automatic third-generation enzyme-linked immunosorbent assay (MEIA). This immunoassay method was carried out according to the instructions of the manufacturer. Borderline and positive results were retested.

RESULTS

Konya is the largest city of Turkey in terms of surface area and one of the economically developed cities. For HBsAg, anti-HBs and anti-HCV screening, whole test results of 5 years are given in Table 1 and Figure 1. The differences between the urban and rural for HBsAg (p = 0.062 > 0.05) and anti-HCV(p = 0.874 > 0.05) were not statistically significant. Among the markers only for anti-HBs, the difference between the urban and rural was statistically significant (P = 0.042 < 0.05). Of them, 4.15 % were positive for HBsAg, 36.46 % were positive for anti-HBs and 1.16 % were positive for anti-HCV.

CONCLUSION

In this study, Konya has been evaluated as two regions: central and peripheral. Our study showed us that distribution of the diseases vary from one region to another. We consider that difference in social diversity is one of the factors. These infections are major health problems. So the results of immunodiagnostic tests for HBsAg, anti-HBs and anti-HCV will be useful for guiding control actions and for new preventive strategies.

A comparison of immuncapture agglutination and ELISA methods in serological diagnosis of brucellosis

BACKGROUND

Different serological tests are used in serologic diagnosis of brucellosis. The most widely used of these are Standard Tube Agglutination and Coombs anti-brucella tests. Whereas ELISA Ig M and Ig G tests have been in use for a long time, immuncapture agglutination test has been recently introduced and used in serological diagnosis. The aim of this study was to compare diagnostic values of ELISA Ig M and Ig G and immuncapture agglutination tests with Coombs anti-brucella test.

METHODS

Sera from 200 patients with presumptive diagnosis of brucellosis were included into the study. Coombs anti-brucella test, ELISA Ig M and Ig G tests and Immuncapture test were investigated in these sera. Then, sensitivity, specificity, negative predictive and positive predictive values were calculated.

RESULTS

Sensitivity, specificity, negative predictive and positive predictive values were found to be 90.6%, 76.3%, 94.2%, and 65.9% respectively for the Immuncapture test, whereas they were found to be 73.7%, 58.9%, 84.2%, and 42.8% for Ig G and 72.2%, 67.8%, 85.2%, and 48.7% for Ig M. The Immuncapture test was found to be compatible with ELISA Ig M and Ig G tests but it was statistically incompatible with Coombs anti-brucella test.

CONCLUSIONS

Immuncapture agglutination test yields similar results to those of Coombs anti-brucella test. This test is a useful test by virtue of the fact that it determines blocking antibodies in the diagnosis and follow-up of brucellosis.