Altinay Bilgic

Characterization of rpoB Mutations in Rifampin-Resistant Clinical Isolates of Mycobacterium tuberculosis from Turkey by DNA Sequencing and Line Probe Assay

ABSTRACT Mutations in an 81-bp region of the rpoB gene associated with rifampin resistance were studied in 41 rifampin-resistant clinical strains of Mycobacterium tuberculosis isolated in Turkey. Fourteen different rpoB alleles, three of which had not been reported before, were found. A reverse hybridization-based line probe assay (the Inno-LiPA Rif.TB test) for rapid detection of the mutations was evaluated with these isolates. Rifampin resistance was correctly identified in 23 of 41 isolates (56.1%) with the kits R probes specific for these mutations. Seventeen of 41 isolates (41.5%) yielded hybridization patterns, with at least one negative signal obtained with the S probes for the wild type. One isolate was identified as rifampin sensitive by the line probe assay. The rate of concordance of the results of the line probe assay with the results of the in vitro susceptibility test was high (97.6%). These results demonstrate that the line probe assay kit may be useful for the rapid diagnosis of rifampin-resistant tuberculosis.

Mycobacterium tuberculosis infection and laboratory diagnosis in solid-organ transplant recipients

Tuberculosis (TB) is an unusual infection in transplant recipients. We evaluated (i) the frequency of TB, (ii) the duration to develop the TB infection, and (iii) clinical consequences, in 380 solid‐organ recipients from January 1995 to December 2000. A total of 10 (2.63%) patients (eight renal, two liver transplant recipients) were found to have post‐transplantation TB. The frequency of TB in this patient population is 8.5‐fold higher than the prevalance in the general Turkish population. Tuberculosis developed within 2–33 months after transplantation, with a median of 15 months. In all of these 10 patients, Mycobacterium tuberculosis (MTB) was isolated from the culture. All the patients continued to have low dose immunosuppressive treatment, and also quadriple antituberculosis treatment [isoniazid (INH), rifampin (RIF), pyrazinamide (PRZ) and ethambutol (ETB)] has been given. The two recipients had died of disseminated form of TB. Relapse was detected in one patient 6 months after the completion of the treatment. As post‐transplant TB infection develops mostly within the first year after transplantation, clinicians should be more careful for early and fast diagnosis and treatment should be started immediately.

Low-dose intradermal versus intramuscular administration of recombinant hepatitis B vaccine: a comparison of immunogenicity in infants and preschool children

Two hundred infants and two hundred preschool children were randomly assigned to receive either 10 micrograms of recombinant hepatitis B vaccine (GenHevac B) intramuscularly (i.m.) or 2 micrograms intradermally (ID) in the deltoid region at 0, 1 and 6 months. Antibody to hepatitis B surface antigen (anti-HBs) was tested eight weeks after the third vaccine dose. Standard dose i.m. and low-dose ID administration of recombinant hepatitis B vaccine produced comparable rates of anti-HBs equal to or higher than 10 mIU ml-1 in infants (98% and 94%, respectively) and preschool children (98% and 100%, respectively). Although i.m. vaccination produced higher anti-HBs concentrations than ID vaccination both in infants (geometric mean titre-GMT, 935 versus 621 mIU ml-1) and preschool children (GMT, 1393 versus 804 mIU ml-1), the differences were not statistically significant (p > 0.05). The preschool children tended to have higher anti-HBs concentrations than the infants. No clinically serious adverse effects were observed in both vaccine groups; however, induration and hyperpigmentation at the injection site were more often seen in the study population that was vaccinated intradermally. We conclude that intradermal administration of 2 micrograms recombinant hepatitis B vaccine is safe and effective in infants and preschool children, and may be an acceptable, less expensive alternative to full-dose i.m. vaccination for mass immunization, especially in developing countries.

TT Virus Infection and Genotype Distribution in Blood Donors and a Group of Patients from Turkey

Abstract.Background: TT virus (TTV) DNA has been found in a large proportion of patients with different forms of non-A-G hepatitis, however the clinical importance is unclear. We aimed to determine the genotypes of TTV isolates foung in blood donors and different patient groups from the western part of Turkey. Materials and Methods: TT DNA was investigated in serum samples of 91 volunteer blood donors (BD), 105 thalassemia (TH) patients, ten patients with fulminant hepatitis (FH) and 16 hemodialysis (HD) patients by heminested PCR using primers NG059, NG061 and NG063 from the ORF1 region. 39 isolates were genotyped by analyzing the partial sequence of ORF1. Results: TTV DNA was found in 75% of HD, 80% of FH, 61% of TH patients and in 51.6% of BD. Among the sequenced isolates, 14 (35.9%) belonged to genotype 1 (G1) and 25 (64.1%) belonged to genotype 2 (G2). Among the G2 sequences, 22 were grouped as G2c. Conclusion: TTV infection was common in the population studied, even with moderately sensitive primers. G2 was the major genotype of the studied population without any significant differences in distribution between various patient groups and BD.

Low-dose intradermal administration of recombinant hepatitis B vaccine in children: 5-year follow-up study.

Several studies have documented the efficacy of low-dose intradermal administration of hepatitis B vaccine. However, little is known about the duration of protection provided by low-dose intradermal administration of hepatitis B vaccine. This study reports results from a 5-year follow up period of 200 healthy children (100 infants and 100 preschool children) immunized intradermally with 2 microg doses of recombinant hepatitis B vaccine (GenHevac B) at months 0,1, and 6. In the 8th week after the third vaccine dose, 97% of the children developed anti-HBs antibodies higher than or equal to 10 mlU ml(-1), and the antiHBs geometric mean titre (GMT) was 676 mlU ml(-1). In month 18 and year 5, the anti-HBs GMT decreased to approximately one-third (220 mlU ml(-1)) and one-tenth (68 mlU ml(-1)) of the initial levels, respectively. However, 87% of the children had protective levels of anti-HBs (> or =10 mlU ml(-1)) after 5 years. Among 156 children followed for 5 years, none became positive for anti-HBc and/or HbsAg. Seven children who were seronegative after 5 years developed anti-HBs antibodies higher than 1000 mlU ml(-1) after an additional 10 microg intramuscular hepatitis B vaccine. Persistent immunologic memory over periods of 5 years or more is evident, the anamnestic antibody response to a booster dose of vaccine, even in these children who have lost antibody. We conclude that intradermal administration of 2 microg recombinant hepatitis B vaccine provides long-term protection against hepatitis B virus in infants and preschool children.

Comparison of Brucella immunoglobulin M and G flow assays with serum agglutination and 2-mercaptoethanol tests in the diagnosis of brucellosis

Abstract The diagnostic value of Brucella IgM/IgG flow assays was evaluated in comparison with serum agglutination and 2-mercaptoethanol tests by testing a selection of serum samples submitted to the laboratory because of clinical suspicion of brucellosis. All 39 admission and 11 follow-up samples that agglutinated in the serum agglutination test tested positive in the flow assay, whereas all 20 serum agglutination negative samples with clinical suspicion of brucellosis, 23 control samples from healthy individuals and 20 control samples from cases with chronic hepatitis tested negative in the flow assay. The Brucella IgM and IgG flow assays were slightly more sensitive than the agglutination tests in discriminating between specific IgM and IgG antibodies. The Brucella IgM and IgG flow assays are easy-to-perform and quick assays that can be used for the diagnosis of brucellosis. The flow assays are very useful, especially in rural settings where brucellosis is widespread and where well-equipped laboratories to perform the laboratory tests are not readily available.

Genotyping of rifampin-resistant Mycobacterium tuberculosis isolates from western Turkey

Background Although the rate of multiple drug resistance is high, there is no published data on the transmission rate of drug-resistant strains of Mycobacterium tuberculosis in the Aegean region of western Turkey that are based on molecular methods. Methods IS6110 and pTBN12 restriction fragment length polymorphism (RFLP) methods were used for typing M. tuberculosis strains isolated from 26 sputum samples from 26 patients. Results Nineteen of the rifampin-resistant isolates (73.1%) contained 6 to 11 copies of IS6110. Eighteen different IS6110 DNA fingerprint patterns were observed in the 26 rifampin-resistant isolates. Twenty-three of the 26 rifampin-resistant isolates were also resistant to isoniazid. When evaluated together, both methods yielded 21 (80.9%) different banding patterns and the level of clustering was 34.6%. The average number per pattern was 1.23 (26/21). Conclusions IS6110 fingerprinting suggests that the rifampin-resistant isolates obtained from the Aegean region had a relatively high clustering rate and were clonally related. These findings showed that the rifampin-resistant isolates are actively transmitted between patients. Urgent measures should be taken to prevent the spread of these resistant strains.

Evaluation of Brucella dipstick assay for the diagnosis of acute brucellosis.

The diagnostic value of the dipstick assay was evaluated by comparison with Rose Bengal (RB), serum aglutination tests (SAT) and 2 mercaptoethanol test (2-ME) on consecutive serum samples submitted because of suspicion of brucellosis. Serum samples of 232 patients with suspected brucellosis that were submitted for laboratory confirmation were included in the study. Twelve out of 232 serum samples were detected as positive with the dipstick assay. All of these 12 patients had positive RB and SAT results. In 16 RB positive samples dipstick test was negative. Fifteen of these samples had insignificant (titer<1/160) or borderline (titer 1/160) SAT results and the clinical symptoms of these patients were consistent with chronic brucellosis rather than acute or recent-onset brucellosis. Dipstick assay is an easy-to-perform assay that can be used for the diagnosis of acute brucellosis especially in rural areas where brucellosis is widespread and in settings where well-equipped laboratories are not available.

Screening for human immunodeficiency virus type 1 and 2 in a Turkish blood donor population

OBJECTIVES To determine the prevalence of human immunodeficiency virus-1 and -2 infection in voluntary blood donors at a university hospital in the third largest city of Turkey and to evaluate the HIV testing strategy for notifying blood donors. METHODS Between July 1995 and August 1997, 36,373 voluntary blood donors who met the criteria for donating blood were tested for the presence of HIV-1 and -2 antibodies by using an automated enzyme-linked fluorescent immunoassay. Repeatedly reactive samples were subjected to a different enzyme-linked immunosorbent assay (ELISA) and a line immunoassay (LIA) for the detection of antibodies. RESULTS Of the 36,373 samples tested 72 were found to be repeatedly reactive or borderline by the first screening enzyme immunoassay (EIA). None of the 72 samples was reactive by the second EIA. These samples were further tested by LIA: 64 were negative on the line immunoassay and 8 were indeterminate. Three of eight donors who had indeterminate results by LIA were tested for HIV-1 DNA by polymerase chain reaction (PCR) and were found to be negative. One additional donor with an indeterminate LIA was found to be negative by EIA and LIA during the 6-month follow-up period. CONCLUSION Donor questioning, repeat EIA testing, LIA testing, and HIV-1 DNA analysis did not confirm evidence for HIV infection among this blood donor population. Blood donor notification of test results according to the World Health Organization (WHO) strategy III was found to be an appropriate approach.

Alpha-Interferon-2b Treatment for Chronic Hepatitis-B Infection in Children with Cancer

We have evaluated the efficacy of treatment with recombinant Interferon-2b (IFN-2b) in 12 children with cancer who developed chronic hepatitis-B infection. Seven of them had lymphoblastic leukaemia and others had solid tumours. Seven cases were male. Mean age was 10.5 years with a range of 5-16 years. Chronic Hepatitis B was diagnosed biochemically, serologically and histopathologically. They were HBsAg(+), HBV-DNA(+), and HCV(-), HIV(-). Seven cases were HBeAg(+) and two of them were anti-Delta IgG(+). Liver biopsy revealed chronic active hepatitis in six cases and persistent hepatitis in three cases. IFN was given at the dose of 5 MU/m2 three times a week, subcutaneously for 6 months. It was well tolerated. After IFN therapy, ALT levels returned to normal in seven cases. All cases were still HBsAg(+). Four of them seroconverted to anti-HBe antibody. Loss of serum HBV-DNA in three cases, but 11 cases showed a marked decrease after IFN. The control liver biopsies showed that histopathological activity index was diminished in five cases. Other 16 patients, serving as control, received no therapy. Five of them were leukaemia and others were solid tumours. Twelve cases were male. Mean age was 9.3 years with a range of 4-19 years. After 6 months, only one patient lost HBV-DNA and three of them seroconverted to anti-HBe with normalization of ALT values. In our study, IFN treatment favourably influenced the progress of chronic hepatitis B in children with cancer.