Serosurveillance study on transmission of H5N1 virus during a 2006 avian influenza epidemic.

In 2006 an outbreak of avian influenza A(H5N1) in Turkey caused 12 human infections, including four deaths. We conducted a serological survey to determine the extent of subclinical infection caused by the outbreak. Single serum samples were collected from five individuals with avian influenza whose nasopharyngeal swabs tested positive for H5 RNA by polymerase chain reaction, 28 family contacts of the cases, 95 poultry cullers, 75 individuals known to have had contact with diseased chickens and 81 individuals living in the region with no known contact with infected chickens and/or patients. Paired serum samples were collected from 97 healthcare workers. All sera were tested for the presence of neutralizing antibodies by enzyme-linked immunoassay, haemagglutination inhibition and microneutralization assays. Only one serum sample, from a parent of an avian influenza patient, tested positive for H5N1 by microneutralization assay. This survey shows that there was minimal subclinical H5N1 infection among contacts of human cases and infected poultry in Turkey in 2006. Further, the low rate of subclinical infection following contact with diseased poultry gave further support to the reported low infectivity of the virus.

Evaluation and comparison of three different anti-hepatitis C virus antibody tests based on chemiluminescence and enzyme-linked immunosorbent assay methods used in the diagnosis of hepatitis C infections in Turkey.

The routine diagnosis of hepatitis C virus (HCV) infection is based on the detection of anti-HCV antibodies by two main methods (enzyme immunoassay [EIA] and chemiluminescence immunoassay [CIA]) but false-positives are a problem. We investigated three anti-HCV tests: two CIAs (Cobas e 601 and Architect i2000SR); and one EIA (Ortho HCV 3.0). Two other anti-HCV tests were also performed as supplementary and confirmatory tests, respectively: a recombinant strip immunoblot assay (RIBA HCV 3.0 SIA) and a reverse transcriptase polymerase chain reaction-based assay for HCV-RNA. After discriminating the false-positive results, the true anti-HCV seropositivity rate in 7156 serum samples was 0.91%. The seropositivity and false-positive rates for the Cobas e 601, Architect i2000SR and Ortho HCV 3.0 anti-HCV tests were 1.9% and 0.99%, 1.2% and 0.29%, and 0.87% and 0.01%, respectively. The mean level of HCV-RNA was 3399 x 10(3) IU/ml. Critical levels for false-positivity for HCV-RNA were a cut-off index of 200 for Cobas e 601, a signal/cut-off (S/CO) of 5 for Architect i2000SR and an S/CO of 1.2 for Ortho HCV 3.0. Positive and negative results for the RIBA HCV 3.0 SIA assay all accorded with the HCV-RNA assay, except for 23 (17%) 'indeterminate' results, all of which were negative with the HCV-RNA assay. In conclusion, to eliminate doubts related to false-positive findings in the initial HCV screening tests, additional confirmatory HCV-RNA assay should be performed.

Correlation of slime production investigated via three different methods in coagulase-negative staphylococci with crystal violet reaction and antimicrobial resistance.

This study investigated slime production by coagulase-negative staphylococci (CNS) using the standard tube (ST), Congo red agar (CRA) plate and Christensen's tube (CT) methods, and compared the results with those of the crystal violet reaction (CVR) test. The potential correlation between slime production and antimicrobial resistance was also evaluated. In total, 205 CNS strains were isolated from biological samples: 92 (44.9%) were shown to produce slime by the ST method; 96 (46.8%) by the CRA plate method; 90 (43.9%) by the CT method; and 89 (43.4%) strains were CVR positive. Eighty-three (40.5%) CNS strains were positive for slime production by the ST, CRA and CT methods. The findings of the ST, CRA and CT test methods were consistent with each other but were not related to CVR positivity. Based on the ST method, rates of antibiotic resistance to several antimicrobial agents were higher in slime-positive strains than in slime-negative strains and, in some cases, this was statistically significant.

Distribution, optimum detection time and antimicrobial susceptibility rates of the microorganisms isolated from blood cultures over a 4-year time period in a Turkish university hospital and a review of the international literature.

This study retrospectively examined 8986 blood cultures from patients over a 4-year time period in an eastern Turkish university hospital to determine the detection times and distribution of isolated microorganisms using the automated BACTEC 9050 and BACTEC 9120 systems. A total of 1914 (21.3%) blood cultures contained pathogenic microorganisms and 252 (2.8%) positive cultures were considered contaminated. Of all the cultures, 18 (0.2%) were false positives and 224 (2.5%) were false negatives. In cultures containing pathogenic microorganisms, Gram-positive and Gram-negative bacterial isolation rates were 436 (22.8%) and 1440 (75.2%), respectively, and yeasts (all Candida sp.) were found in 38 (2.0%) cultures. Coagulase-negative staphylococci occurred in 936 (48.9%) cultures and Staphylococcus aureus occurred in 302 (15.8%) cultures. The mean detection time for all of the pathogens was 21 h and Brucella spp were isolated within 10 days. This study helps in understanding the epidemiology of the region and in providing positive therapeutic approaches. A review of the international literature helps to place this understanding into a global context.

Change in serum concentrations of interleukin-2 and interferon-gamma during treatment of tuberculosis.

We aimed to investigate changes in serum concentrations of the cytokines interleukin (IL)-2 and interferon (IFN)-gamma during the clinical course of active tuberculosis, to establish the presence of cellular immunity before and after treatment. Blood samples were taken from 18 patients with active tuberculosis before and 2 months after therapy; IL-2 and IFN-gamma concentrations were evaluated. The mean serum IL-2 concentration before therapy was 164.5 pg/ml (range 12-980 pg/ml) and the concentration 2 months after therapy was 92.11 pg/ml (range 1-490 pg/ml). The mean serum IFN-gamma concentrations were 10.83 pg/ml (range 1-22.2 pg/ml) and 4.64 pg/ml (range 1-28.5 pg/ml), respectively. The decrease in concentrations of both cytokines after therapy was statistically significant. Further studies investigating the benefits of adding cytokines to drug treatment for tuberculosis are needed.