Comparison of a novel antigen detection test with reverse transcription polymerase chain reaction assay for laboratory diagnosis of SARS-CoV-2 infection.

Molecular diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by real-time reverse transcription polymerase chain reaction (RT-PCR) in respiratory specimens is considered the gold standard method. This method is highly sensitive and specific but it has some limitations such as being expensive and requiring special laboratory equipment and skilled personnel. RapidFor™ Antigen Rapid Test Kit is a commercially available Ag-RDT which is produced in Turkey and designed to detect the nucleocapsid antigen of SARS-CoV-2 in nasopharyngeal swab samples. The aim of this study was to evaluate the performance of this novel SARS-CoV-2 antigen detection considering the RT-PCR method as the gold standard. Four hundred forty-four nasopharyngeal swab samples which were collected from the patients who met clinical criteria of COVID-19 from ten centers in Turkey between September 2020 and February 2021 were included in the study. All the nasopharyngeal swab samples were tested for SARS-CoV-2 RNA using commercial RT-PCR kits (Bioeksen and A1 Lifesciences, Istanbul, Turkey) according to the manufacturer's instructions. Viral loads were assessed according to the cycle threshold (Ct) values. RapidFor™ SARS-CoV-2 antigen test (Vitrosens Biotechnology, Istanbul, Turkey) was used to investigate the presence of SARS-CoV-2 antigen in all samples following the manufacturer's instructions. Out of 444 nasopharyngeal swab samples tested, 346 (77.9%) were positive and 98 (22.1%) were negative for SARS-CoV-2 RNA by RTPCR. Overall sensitivity of the RapidFor™. Antigen Rapid Test Kit was 80.3% whereas specificity was found to be 87.8%. Positivity rate of rapid antigen test in samples with Ct values over 25 and below 30 was 82.7%, while it increased to 95.7% in samples 20 ≤ Ct < 25 and reached 100% in samples with Ct values below 20. RapidFor™ SARS-CoV-2 Ag test might be a good choice in the screening of symptomatic and asymptomatic patients and their contacts for taking isolation measures early, with advantages over RT-PCR as being rapid, easy and being applicable in every laboratory and even at point of care.

[Analysis of Mycobacterium tuberculosis Complex Strains Isolated from the Samples of Patients Living in Northern Syria]. / Suriye'nin Kuzeyinde Yasayan Hastalarin Örneklerinden Üretilen Mycobacterium tuberculosis Kompleks Izolatlarinin Analizi.

Tuberculosis causes serious mortality and morbidity worldwide each year. A lot of effort and money is spent for the diagnosis and treatment of tuberculosis all over the world. The importance that countries give to health policies and public health is inversely proportional to the incidence of tuberculosis and multidrug resistant tuberculosis. The aim of our study was to evaluate the resistance profiles of Mycobacterium tuberculosis complex strains which were isolated from sputum samples, collected by World Health Organisation from patients living in the northern region of Syria, where health services were disrupted due to the civil war. According to the protocol signed between the World Health Organization and our hospital; sputum samples taken from tuberculosis patients living in Afrin, Azez and Idlib regions or suspected of being resistant to anti-tuberculosis drugs were studied in our hospital. The cultivation process was performed in our laboratory using Löwenstein Jensen media and MGIT-960 system. The susceptibility tests for primary anti-tuberculosis drugs were performed using MGIT-960 system for M.tuberculosis complex isolates. The isolates identified as MDR/RD-TB (multi-drug-resistant-rifampicin-resistant tuberculosis) were sent to National Tuberculosis Reference Laboratory of Public Health Institution of Türkiye for susceptibility testing to first and second line drugs. Mutation and wild-type determination were studied by "Line Probe Assay (LPA)" method to investigate the susceptibility of the isolates to isoniazid, rifampicin, fluoroquinolone and aminoglycoside/cyclic peptide. The results obtained from the patients were collected and evaluated retrospectively from the records. Growth was observed in 18 samples out of 171 sputum samples from 67 patients; 13 isolates were detected as MDR-TB while one isolate was detected as mono RR-TB. The rate of mono RR-TB was 1.5% and the rate of MDR-TB was 19.4%. MUT3 causing rifampicin resistance was detected in 17.9% of the patients, katG/MUT1 causing isoniazid resistance in 17.9% and WT loss causing aminoglycoside/cyclic peptide resistance were detected in 19.4% of the patients. Neither fluoroquinolone resistance nor a mutation leading to fluoroquinolone resistance was detected in the study. When the sputum samples taken from the patients living in Northern Syria were examined, the frequency of MDR-TB was found to be quite high. MDR-TB, which is an important public health problem, was found at high rates due to the internal turmoil in the region and poor accessibility to health services. Since the gene mutations causing drug resistance with the LPA method differ with the conducted studies, it is important to evaluate the dominant gene mutations for determining the TB treatment strategies in the region.

An investigation into respiratory tract viruses in children with acute lower respiratory tract infection or wheezing.

BACKGROUND: This study aimed to determine the frequencies of respiratory tract viruses in patient (acute lower respiratory tract infection [LRTI] or wheezing) and control (history of asthma without symptoms) groups. METHODS: Using multiplex-polymerase chain reaction (PCR), respiratory tract viruses were investigated in the respiratory tract specimens from patient and control groups followed in the Pediatric Clinic. RESULTS: The viruses detected in the patient and control groups (P=0.013) were as follows, respectively: rhinoviruses A, B, C (25.6% and 36.7%), influenza virus A (21.1% and 0.0%), parainfluenza virus type 1 (7.8% and 1.7%), parainfluenza virus type 4 (5.6% and 0.0%), adenoviruses A, B, C, D, E (4.4% and 1.7%), parainfluenza virus type 3 (4.4% and 1.7%), coronaviruses 229E and NL63 (4.4% and 1.7%), coronavirus OC43 (3.3% and 0.0%), respiratory syncytial virus A (3.3% and 0.0%), parainfluenza virus type 2 (2.2% and 0.0%), influenza virus B (2.2% and 0.0%), and respiratory syncytial virus B (1.1% and 1.7%). No bocavirus, metapneumovirus or enterovirus was found in any specimen. Statistically significant differences in the detection of influenza virus A (P=0.000), the total detection of parainfluenza viruses (P=0.008) and coinfection (P=0.004) were observed between the patient and control groups. CONCLUSIONS: The advantage of our study compared with other studies is the inclusion of not only wheezing patients but also children with asthma without symptom. The higher detection of rhinoviruses both in patient and control groups give rise to thought that these viruses may be responsible for asthma exacerbations and may be related with long duration of virus shedding.

The Prevalence of Mixed Genotype Infections in Turkish Patients with Hepatitis C: a Multicentered Assessment.

BACKGROUND: HCV virus infections are one of the major health problems in the world that can cause cirrhosis and liver cancer at a higher rate than other hepatitis data. The aim of this study was to determine the prevalence of mixed infections with different HCV genotypes in Turkey and also to evaluate the current HCV genotype and sub-type distributions by a multicentered assessment. METHODS: The HCV genotype data of 17,578 hepatitis C patients collected from 23 centers from different geographic regions covering all Turkey were collected. The data included information about the HCV genotypes in the last 10 years (between 2007 and 2016), demographic properties of the patients and the methods/systems used to determine the genotypes. RESULTS: Two hundred twenty-eight of the patients (1.3%) had mixed genotype. The most common mixed genotype combination was 1b + 4 (0.83%) followed by 1a + 1b (0.26%). Genotype distribution varies according to geographical regions. However, genotype 1 (82.92%) was the most common genotype in all regions and all years. This was followed by genotype 3 (7.07%) and genotype 4 (5.43%). A variety of methods were used by the centers including sequencing, pyrosequencing, real-time PCR, in-house RFLP, reverse hybridization (LIPA), and hybridization. CONCLUSIONS: Infection with mixed HCV genotypes in Turkey is uncommon. Genotype distribution varies according to geographic regions; the most common genotype 1 is encountered all over the country, while genotypes 3 and 4 are only in some of the centers. Since there is limited information about mixed HCV infection, further investigations are needed to determine the clinical importance of mixed HCV infection.

[Two cases of visceral leishmaniasis from Kahramanmaras, Turkey]. / Kahramanmaras'da saptanan iki viseral leysmanyazis olgusu.

Turkey is an endemic area for cutaneous leishmaniasis (CL) according to the data of World Health Organization. CL is more widely distributed in Sanliurfa region (located at south-eastern part of Anatolia) of Turkey, while visceral leishmaniasis (VL) is reported sporadically from all parts of Turkey, especially in pediatric cases. However VL has not been reported from our region yet. Here we report two cases of VL from Kahramanmaras region (located at eastern part of South Anatolia), one of which was a 57-year-old immuncompromised patient and the other was a 18-year-old immunocompetent patient. The common symptoms of the patients were high fever, hepatosplenomegaly and pancytopenia. The diagnosis of both patients was made by demonstration of the amastigotes of parasite in Giemsa-stained smears prepared from bone marrow aspiration samples, and isolation of promastigotes from cultures in NNN medium. The isolates were identified as Leishmania donovani with PCR and sequencing methods. Both of the patients were treated successfully with liposomal amphotericin B, resulting in complete cure. In conclusion, cases with fever of unknown origin, hepatosplenomegaly, pancytopenia and hypergammaglobulinemia should be considered in terms of VL especially in Kahramanmaras region.

Evaluation of real-time PCR and flow cytometry efficiency in rapid detection of carbapenemase-producing Enterobacteriales.

INTRODUCTION: Infections due to carbapenem-resistant Enterobacteriales, which have increased worldwide in recent years, cause concern. This study aimed to rapidly detect carbapenemase gene region by using flow cytometry in Enterobacteriales isolates and to evaluate its efficiency and susceptibility by comparing it with polymerase chain reaction (PCR). METHODOLOGY: In the study, 21 isolates obtained from the blood cultures of patients hospitalized in intensive care units and found to intermediate or resistant to at least one carbapenem in the automated system, and 14 isolates belonging to the carbapenem-susceptible Enterobacteriales family were included. Carbapenemase gene regions were investigated by PCR after their susceptibility was determined by disk diffusion method. Bacterial suspensions were treated with meropenem + specific carbapenemase inhibitors (EDTA or APBA) and Temocillin and stained with thiazole orange (TO) and propidium iodide (PI) to show dead/live cell differentiation. Dead/live cell percentages were calculated after reading on the flow cytometer device. RESULTS: In the ROC analysis of the flow cytometry method, the cut-off value, specificity, and susceptibility of PI staining rates for meropenem were found as 14.37%, 100%, and 65%, respectively. It was found that the flow cytometry method was well-compatible with PCR in the detection of the carbapenemase gene region. CONCLUSIONS: Flow cytometry will continue to be a promising method for the detection of antimicrobial susceptibility and resistance due to its rapid analysis of many cells and its high compatibility with PCR results.

The prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae in the endocervical swab specimens of symptomatic, asymptomatic and infertile women in Turkey.

PURPOSE: To investigate C. trachomatis and N. gonorrhoeae prevalence in three different female populations in Turkey. METHODS: A total of 370 women, 170 symptomatic, 100 asymptomatic, and 100 infertile, were included. Of the endocervical specimens collected from all women using a Dacron swab, the first one was taken to Stuart's transport medium to culture, while the second one was transferred onto slides to perform direct fluorescent antibody test (DFA) and Gram staining, and the third specimen was used for Becton Dickinson BDProbeTec ET system (BDPT). RESULTS: C. trachomatis was detected in 5.16% of symptomatic, 1.11% of asymptomatic, and 2.15% of infertile women with BDPT. Sensitivity and specificity of the DFA test were 72.73 and 97.85%, respectively. N. gonorrhoeae was detected in 2.42% of symptomatic and in 1.02% of infertile women. N. gonorrhoeae was not detected in any asymptomatic women. In N. gonorrhoeae-positive patients, sensitivity and specificity of culture were 60 and 100%, respectively, while they were 80 and 100% for BDPT. CONCLUSIONS: Prevalence of N. gonorrhoeae and C. trachomatis was detected to be low in Turkish women, and the difference between the groups was not significant. Both agents were more prevalent in subjects over 25 years of age.

Identification of Recent Tuberculosis Exposure Using QuantiFERON-TB Gold Plus, a Multicenter Study.

We investigated whether the difference of antigen tube 2 (TB2) minus antigen tube 1 (TB1) (TB2-TB1) of the QuantiFERON-TB gold plus test, which has been postulated as a surrogate for the CD8+ T-cell response, could be useful in identifying recent tuberculosis (TB) exposure. We looked at the interferon gamma (IFN-γ) responses and differences in TB2 and TB1 tubes for 686 adults with QFT-plus positive test results. These results were compared among groups with high (368 TB contacts), low (229 patients with immune-mediated inflammatory diseases [IMID]), and indeterminate (89 asylum seekers or people from abroad [ASPFA]) risks of recent TB exposure. A TB2-TB1 value >0.6 IU·ml-1 was deemed to indicate a true difference between tubes. In the whole cohort, 13.6%, 10.9%, and 11.2% of cases had a TB2>TB1 result in the contact, IMID, and ASPFA groups, respectively (P = 0.591). The adjusted odds ratios (aORs) for an association between a TB2-TB1 result of >0.6 IU·ml-1 and risk of recent exposure versus contacts were 0.71 (95% confidence interval [CI], 0.31 to 1.61) for the IMID group and 0.86 (95% CI, 0.49 to 1.52) for the ASPFA group. In TB contact subgroups, 11.4%, 15.4%, and 17.7% with close, frequent, and sporadic contact had a TB2>TB1 result (P = 0.362). The aORs versus the close subgroup were 1.29 (95% CI, 0.63 to 2.62) for the frequent subgroup and 1.55 (95% CI, 0.67 to 3.60) for the sporadic subgroup. A TB2-TB1 difference of >0.6 IU·ml-1 was not associated with increased risk of recent TB exposure, which puts into question the clinical potential as a proxy marker for recently acquired TB infection. IMPORTANCE Contact tuberculosis tracing is essential to identify recently infected people, who therefore merit preventive treatment. However, there are no diagnostic tests that can determine whether the infection is a result of a recent exposure or not. It has been suggested that by using the QuantiFERON-TB gold plus, an interferon gamma (IFN-γ) release assay, a difference in IFN-γ production between the two antigen tubes (TB2 minus TB1) of >0.6 IU·ml-1 could serve as a proxy marker for recent infection. In this large multinational study, infected individuals could not be classified according to the risk of recent exposure based on differences in IFN-γ in TB1 and TB2 tubes that were higher than 0.6 IU·ml-1. QuantiFERON-TB gold plus is not able to distinguish between recent and remotely acquired tuberculosis infection, and it should not be used for that purpose in contact tuberculosis tracing.

Genotyping Leishmania promastigotes isolated from patients with cutaneous leishmaniasis in south-eastern Turkey.

Objective Cutaneous leishmaniasis (CL) is a significant disease in south-eastern Anatolia because it is prevalent among Syrian refugees. We identified the causative Leishmania species in CL patients using molecular methods. Methods Novy-MacNeal-Nicolle medium was inoculated with aspirated fluid from suspected CL lesions and tested for amastigotes with Giemsa staining. PCR amplified the internal transcribed spacer 1 (ITS1) of the Leishmania genome in cultures containing Leishmania promastigotes from 100 patients, which were genotyped with a restriction fragment length polymorphism (RFLP) analysis. A phylogenetic tree was constructed from ITS1 sequences of 95 culture fluid samples from these patients. Results Leishmania amastigotes were detected in 92% of cultures with growth. Leishmania promastigotes were typed as Leishmania tropica with both PCR-RFLP and sequencing. Conclusions Identification of L. tropica as the causative agent of CL in our region allows the clinical course to be predicted, and guides treatment decisions and preventive measures.

A comparison of the in vivo neoendothelialization and wound healing processes of three atrial septal defect occluders used during childhood in a nonrandomized prospective trial.

OBJECTIVE: We prospectively investigated the neoendothelialization of transcatheter secundum atrial septal defect (ASD) closure in children receiving one of three different occluders. METHODS: Transcatheter ASD closure was performed for 44 children. The patients were divided into three groups: group I: Amplatzer, group II: Lifetech CeraFlex, and group III: Occlutech Figulla Flex II septal occluder. The data were prospectively analyzed. Markers of the three phases of wound healing were studied in all patients before and on the 1st and 10th days and 1st month post intervention. RESULTS: The mean age of children was 7.08±3.51 years, and the mean weight was 26.07±15.07 kg. The mean ASD diameter was 12.65±3.50 mm. Groups I, II, and III comprised 34.1%, 31.8%, and 34.1% patients, respectively. No significant differences were observed between the groups regarding patient number, age, defect size, device diameter, or total septum/device ratio (p>0.05). Inflammatory and proliferative phase marker levels increased following the procedure (p<0.05). However, scar formation markers did not change after 1 month. No significant differences in neoendothelializaton were observed among the different occluders (p>0.05). CONCLUSION: All three devices were composed of nitinol with different surface coating techniques. Although the different manufacturing features were claimed to facilitate of neoendothelialization, no differences were observed among the three devices 1 month following the procedure.

Automatized PCR evaluation of Mycobacterium tuberculosis complex in respiratory and nonrespiratory specimens.

In this study, Mycobacterium tuberculosis complex isolates recovered from respiratory and nonrespiratory specimens with culture were evaluated using an automatized PCR method. Specimens with suspected tuberculous disease were decontaminated and concentrated using the standard N-acetyl-L-cysteine NaOH method and were inoculated onto glycerol-supplemented Löwenstein-Jensen media and BACTEC B12 vials. Forty-one specimens with typical colonies on solid media and 127 specimens identified as M. tuberculosis complex in a BACTEC system were selected as the study group. As the control group, 46 specimens without growth on either culture media were selected. The PCR results were positive in 33 (80.5%) and 87 (68.5%) samples that were culture-positive on solid and liquid media, respectively. All (100%) culture-negative specimens within the control group were also negative in the COBAS AMPLICOR Mycobacterium tuberculosis (MTB) PCR method. In conclusion, although it is a fast method for identifying M. tuberculosis complex isolates from clinical specimens, the COBAS AMPLICOR MTB PCR method is found to be less sensitive than culture techniques, we propose therefore that it should only be used in combination with culture results in the clinical diagnosis of tuberculosis.

Immunomodulation therapy in children with chronic hepatitis B.

PURPOSE: The aim of this study is to investigate the effects of HBsAg vaccine and levamisole on virological indicators in naive patients suffering from chronic hepatitis B (CHB) and in healthy carriers of hepatitis B. METHOD: Vaccination and treatment with levamisole were applied to 93 minor patients in total, 43 of them inactive CHB carriers and 50 patients suffering from CHB. RESULTS: 15 (30%) of 50 patients who had high ALT values in the beginning of the study had normal values after treatment. In nine (12%) patients, posttreatment ALT values were higher than pretreatment values, and six (10%) patients showed HBV-DNA loss. In spite of the presence of 50 (54%) HBeAg-positive patients before treatment, 17 (34%) patients proved to be HBeAg-negative after treatment. HBeAg sero-conversion was seen in 10 (20%) cases. In two (2%) patients, HBsAg sero-conversion occurred. CONCLUSION: It was found that treatment with levamisole and vaccine had positive effects on CHB patients and healthy carriers with respect to HBV DNA loss, HBeAg sero-conversion and ALT normalization. The viral load increases and ALT increases that occurred in certain cases were thought to be related to the early immune response. It was determined that combined levamisole and vaccine therapy had no additional positive effect.

A rare cause of anemia and thrombocytopenia in a newborn: congenital malaria.

A newborn with fever and jaundice was referred to our hospital with anemia and thrombocytopenia of unknown origin. The patient's mother suffered from malaria infection during the third trimester of her pregnancy, but she did not accept medical therapy. On physical examination the newborn showed mild splenomegaly and jaundice. Laboratory tests revealed marked anemia with a hemoglobin value of 7.7 g/L and thrombocytopenia with platelet numbers of 17,000/mm3. Plasmodium vivax was detected in blood smear. Oral therapy with chloroquine and primaquine was started. This patient is the second case of congenital malaria reported from Turkey, and shows that the diagnosis of congenital malaria should be considered in infants with suspected congenital infection who are born to mothers with a history of malarial disease. We emphasize the importance of adequate antenatal medical therapy during pregnancy.

Determination of genotypic varieties and genotyping of multiple drug-resistant tuberculosis by the RFLP and spoligotyping methods.

BACKGROUND/AIM: The purpose of the present study was to determine the distribution and epidemiological features of mycobacteria with molecular methods. MATERIALS AND METHODS: Fifty-five culture-positive samples were analyzed by polymerase chain reaction-restriction enzyme length polymorphism (PCR-RFLP) at species level, and their molecular typing was performed with spoligotyping. The IS6110 region and the locus of gene coding for Hsp65 were amplified. RFLP profiles were obtained by cutting the Hsp65 region with the Hae III and BstE II (Eco91I) enzymes. Spoligotyping was carried out by commercial kit. The H37Rv strain was used as the control. RESULTS: All samples showed the same cutting pattern with the H37Rv strain. The RFLP profiles of 9 strains identified as "mycobacteria other than tuberculosis" were compatible with the M. tuberculosis complex. Spoligotyping of 55 isolates detected 13 different genetic profiles. The Beijing genotype was not detected. One isolate was described as an orphan strain according to the SpolDB4 database. The most frequently detected family was T1 with 32 strains (64%), followed by 9 isolates (18%) belonging to the LAM7 TUR family. CONCLUSION: PCR-RFLP is a specific, rapid, and effective method in routine diagnosis of mycobacteria. Spoligotyping is an ideal method in the determination of genotypic varieties of mycobacteria.

Thrombocytopenia in brucellosis: case report and literature review.

BACKGROUND: Brucellosis, constituting a major health problem in many parts of the world--particularly in the Mediterranean and the Middle East--is a multisystem disease with a broad spectrum of clinical manifestations. Hematological abnormalities ranging from a fulminant state of disseminated intravascular coagulopathy to subtle hemostatic alterations have been reported in brucella infection. Immunemediated thrombocytopenia is also a clinically important mechanism that can be encountered during brucellosis. CASE: A young lady with fever was referred to a university hospital because of thrombocytopenia. The provisional diagnosis was idiopathic thrombocytopenic purpura, as the bone marrow examination showed an increased number of megakaryocytes and the absence of fever after hospitalization. The patient responded well to corticosteroid treatment. However, she was finally diagnosed with brucellosis with positive bone marrow and blood cultures for B. abortus and agglutination test of 1:320. The patient was discharged from the hospital 10 days later in good health on rifampicin and doxycycline therapy. The follow-up of the patient revealed normal hematological findings together with a progressive reduction in the titer of the agglutination test for brucella. CONCLUSION: Brucella infection may cause severe thrombocytopenia, mimicking a primary hematological disease that is reversible after appropriate antimicrobial therapy. In cases of brucellosis-induced immune thrombocytopenic purpura, a short-term standard dose of corticosteroid treatment might be an alternative and additional treatment as an urgent approach for thrombocytopenia while initiating antibrucellosis treatment.

Determination of antimicrobial susceptibility patterns and inducible clindamycin resistance in Staphylococcus aureus strains recovered from southeastern Turkey.

BACKGROUND: In this study, we determined the susceptibility patterns of Staphylococcus aureus strains to various antimicrobials and prevalence of inducible clindamycin resistance (ICR) in these isolates. METHODS: Two hundred and one S aureus strains, isolated from various clinical samples, were included in the study. Antibiotic susceptibilities were studied by disc diffusion method on the basis of the guidelines by the Clinical and Laboratory Standards Institute. The disc diffusion induction test (D test) was applied to determine ICR resistance among erythromycin-resistant S aureus isolates. RESULTS: Of the 201 S aureus strains, 101 (50.2%) were resistant to methicillin. All strains were susceptible to vancomycin, teicoplanin, quinupristin/dalfopristin, and linezolid. It was found that 54 (53.4%) methicillin-resistant S aureus (MRSA) strains were erythromycin resistant, and 40 (39.6%) of them showed constitutive clindamycin resistance. ICR was detected in seven (6.9%) MRSA strains. It was found that 13 (13.0%) methicillin-susceptible S aureus (MSSA) strains were erythromycin resistant. Constitutive clindamycin resistance was seen in one (1.0%) MSSA strain, and ICR was detected in 10 (10.0%) cases. CONCLUSION: There was a high rate of methicillin resistance among S aureus strains in our hospital. However, no statistically significant difference of ICR was observed between MRSA and MSSA strains (p=0.434) or between inpatients and outpatients (p=0.804). It was concluded that ICR should be routinely evaluated in each S aureus case to avoid therapy failure among patients.

Evaluation of a polymerase chain reaction amplification method for Mycobacterium tuberculosis complex on samples from different sources.

Using primers specific for the IS6110 region of Mycobacterium tuberculosis complex, successful amplification by the polymerase chain reaction was demonstrated in 81 of 84 archive specimens from patients who had been clinically diagnosed 2 months to 16 y previously as having tuberculosis. Depending on the time of storage of the specimens, extra DNA bands were found in addition to the IS6110 region band.