BACKGROUND: Rifampicin (RFP) is one of the principal first-line drugs used in combination chemotherapies against Mycobacterium tuberculosis, and its use has greatly shortened the duration of chemotherapy for the successful treatment of drug-susceptible tuberculosis. Compensatory mutations have been identified in rpoC that restore the fitness of RFP-resistant M. tuberculosis strains with mutations in rpoB. To investigate rpoC mutation patterns, we analyzed 93 clinical M. tuberculosis isolates from patients in South Korea. METHODS: Drug-resistant mycobacterial isolates were cultured to determine their susceptibility to anti-tubercular agents. Mutations in rpoC were identified by sequencing and compared with the relevant wild-type DNA sequence. RESULTS: In total, 93 M. tuberculosis clinical isolates were successfully cultured and tested for drug susceptibilities. They included 75 drug-resistant tuberculosis species, of which 66 were RFP-resistant strains. rpoC mutations were found in 24 of the 66 RFP-resistant isolates (36.4%). Fifteen different types of mutations, including single mutations (22/24, 91.7%) and multiple mutations (2/24, 8.3%), were identified, and 12 of these mutations are reported for the first time in this study. The most frequent mutation involved a substitution at codon 452 (nt 1356) resulting in amino acid change F452L. CONCLUSION: Fifteen different types of mutations were identified and were predominantly single-nucleotide substitutions (91.7%). Mutations were found only in dual isoniazid- and RFP-resistant isolates of M. tuberculosis. No mutations were identified in any of the drug-susceptible strains.
Base Sequence ; Codon ; Drug Resistance, Multiple ; Drug Therapy ; Drug Therapy, Combination ; Humans ; Korea* ; Mycobacterium tuberculosis* ; Mycobacterium* ; Rifampin ; Tuberculosis ; Tuberculosis, Multidrug-Resistant

BACKGROUND: Pyrazinamide (PZA) is an effective antitubercular drug that becomes toxic to Mycobacterium tuberculosis when converted to pyrazinoic acid by pyrazinamidase (PZase), encoded by mycobacterial pncA. A strong association was noted between the loss of PZase activity and PZA resistance. The causative organisms in extrapulmonary tuberculosis are rarely cultured and isolated. To detect pncA mutations in specimens from extrapulmonary tuberculosis as confirmative diagnosis of mycobacterial infection and alternative susceptibility test to PZA. METHODS: Specimens were collected from clinically proven extrapulmonary tuberculosis. pncA was sequenced and compared with wild-type pncA. RESULTS: pncA from 30 specimens from 23 donors were successfully amplified (56.6% in specimens, 59% in donors). Six mutations in pncA were detected (20.0% in amplified specimens, 26.1% in specimen donors) at nucleotide positions of 169, 248 and 419. The mutation at position 169 results in substitution of aspartic acid for histidine, a possible allelic variation of M. bovis that have intrinsic PZA resistance. The mutation at position 248 changes proline into arginine and that at position 419, arginine into histidine. CONCLUSION: DNA-based diagnosis using pncA may be simultaneously useful for the early diagnosis of mycobacterial infection and the rapid susceptibility to PZA in extrapulmonary tuberculosis. A potential implication of pncA allelic variation at 169 might be suggested as a rapid diagnostic test for M. bovis infection or Bacille Calmette-Guerin (BCG) reactivation.
Amidohydrolases ; Antitubercular Agents ; Arginine ; Aspartic Acid ; Diagnostic Tests, Routine ; Early Diagnosis ; Histidine ; Humans ; Mycobacterium bovis ; Mycobacterium tuberculosis ; Proline ; Pyrazinamide ; Tissue Donors ; Tuberculosis

Mycobacterium massiliense, an emerging pathogen that is increasingly reported as a causative agent in infections occurring during medical procedures, is difficult to be identified using conventional methods. Here we report the case of a cutaneous M. massiliense infection that was associated with repeated surgical procedures and that was identified via a comparative sequence analysis of rpoB and hsp65. The patient showed a substantial response to treatment with a combination of antimicrobial therapies consisting of clarithromycin, amikacin, and cefoxitin for 6 months.
Amikacin ; Cefoxitin ; Clarithromycin ; Humans ; Mycobacterium ; Sequence Analysis

PURPOSE: The differential diagnosis for a pulmonary nodule is intriguing in cancer patients. Metastasis might be a preferential diagnosis, and yet possibilities of other medical conditions still exist. Pulmonary tuberculosis should be enlisted in the differential diagnosis for a pulmonary nodule in cancer patients in Korea. This study was aimed at analyzing the incidence and clinical features of pulmonary tuberculosis that were misdiagnosed as pulmonary metastasis during radiologic follow-up in pediatric cancer patients. METHODS: We retrospectively studied 422 cancer patients less than 18 years old in the Korea Cancer Center Hospital from January 2001 to June 2007. We collected episodes of lung metastasis of primary tumor and tuberculosis during treatment or follow-up, and analyzed medical records. RESULTS: There were 5 cases of tuberculosis confirmed after surgery which were initially regarded as cancer. Two patients had respiratory symptoms such as cough and sputum but the other 3 patients did not. One patient had a family history of tuberculosis. Acid-fast M. tuberculosis was found in one case upon tissue specimen analysis. Two cases were Mantoux positive and the sputum examination was negative in all cases. The polymerase chain reaction for tuberculosis on a pathologic specimen was used to differentiate M. tuberculosis from non-tuberculosis mycobacterium (NTM). It was positive in one case. Lung lesions in one case showed a concurrence of tuberculosis along with lung metastasis. One of these patients died after cancer recurrence. CONCLUSION: It is necessary to consider the possibility of tuberculosis when a lung mass is newly detected during treatment or follow-up in patients with childhood cancer.
Cough ; Diagnosis, Differential ; Follow-Up Studies ; Humans ; Incidence ; Korea ; Lung ; Medical Records ; Mycobacterium ; Neoplasm Metastasis ; Polymerase Chain Reaction ; Recurrence ; Retrospective Studies ; Sputum ; Tuberculosis ; Tuberculosis, Pulmonary

In this study, new real-time PCR method based on the groEL gene was developed and investigated. Four spotted fever group (SFG) strains, four typhus group (TG) strains, and four scrub typhus group (STG) strains were easily differentiated as a distinct entity. This PCR assay was applied to detect Rickettsia DNA from 100 ticks. Twelve Haemaphysalis longicornis ticks were found positive and identified as spotted fever group Rickettsia. This real-time PCR method could simultaneously perform the rapid identification of rickettsiae and the differential diagnosis of SFG, TG, and STG in a single reaction.
Diagnosis, Differential ; DNA ; Fever ; Polymerase Chain Reaction ; Real-Time Polymerase Chain Reaction ; Rickettsia ; Scrub Typhus ; Ticks ; Typhus, Epidemic Louse-Borne

BACKGROUNDS: Mutations of katG and inhA (ORF and promoter) are known to be related to isoniazid (INH) resistance of Mycobacterium tuberculosis. Because reports on these mutations in Korean isolates are limited (i.e. only the frequency of katG codon 463 was evaluated.), we tried to know the kinds of mutations of two genes and their frequencies in INH resistant Korean M. tuberculosis strains. METHODS: PCR was performed to amplify katG (2,223 bp), inhA ORF (-77~897, 975 bp), and inhA promoter (-168~80, 248 bp) from 29 multidrug resistant M. tuberculosis (MDR-TB) DNAs prepared by bead beater-phenol method. Their sequences were determined and analyzed by ABI PRISM 3730 XL Analyzer and MegAlign package program, respectively. RESULTS: All of the isolates had more than one mutation in katG or inhA gene. Twenty seven (93%) of 29 tested strains had katG mutations, which suggests that katG is a critical gene determining INH resistance of M. tuberculosis. Amino acid substitutions, such as Arg463Leu and Ser315Thr, due to point mutations of the katG were the most frequent (62.1% and 55.2%) mutations. In addition, deletion of the katG gene was frequently observed (17.2%). Analyzed Korean MDR-TB isolates also had variable inhA mutations. Point mutation of inhA promoter region, such as -15 (C-->T) was frequently found. Substitution of amino acid (Lsy8Asn) due to point mutation (AAA-->AAC) of inhA ORF was found in 1 isolate. Interestingly, 14 point mutated types that were not previously reported were newly found. While four types resulted in amino acid change, the others were silent mutations. CONCLUSIONS: Although it is not clear that the relationship of these newly found mutations with INH resistance, they show marked diversity in Korean MDR-TB strains. It also suggests their feasibility as a molecular target to supplement determining the INH resistance of clinical isolates because of the possible existence of low-level INH resistant strains.
Amino Acid Substitution ; Animals ; Codon ; DNA ; Ecthyma, Contagious ; Isoniazid ; Mycobacterium tuberculosis ; Point Mutation ; Polymerase Chain Reaction ; Promoter Regions, Genetic ; Tuberculosis*

BACKGROUNDS: Mutations of katG and inhA (ORF and promoter) are known to be related to isoniazid (INH) resistance of Mycobacterium tuberculosis. Because reports on these mutations in Korean isolates are limited (i.e. only the frequency of katG codon 463 was evaluated.), we tried to know the kinds of mutations of two genes and their frequencies in INH resistant Korean M. tuberculosis strains. METHODS: PCR was performed to amplify katG (2,223 bp), inhA ORF (-77~897, 975 bp), and inhA promoter (-168~80, 248 bp) from 29 multidrug resistant M. tuberculosis (MDR-TB) DNAs prepared by bead beater-phenol method. Their sequences were determined and analyzed by ABI PRISM 3730 XL Analyzer and MegAlign package program, respectively. RESULTS: All of the isolates had more than one mutation in katG or inhA gene. Twenty seven (93%) of 29 tested strains had katG mutations, which suggests that katG is a critical gene determining INH resistance of M. tuberculosis. Amino acid substitutions, such as Arg463Leu and Ser315Thr, due to point mutations of the katG were the most frequent (62.1% and 55.2%) mutations. In addition, deletion of the katG gene was frequently observed (17.2%). Analyzed Korean MDR-TB isolates also had variable inhA mutations. Point mutation of inhA promoter region, such as -15 (C-->T) was frequently found. Substitution of amino acid (Lsy8Asn) due to point mutation (AAA-->AAC) of inhA ORF was found in 1 isolate. Interestingly, 14 point mutated types that were not previously reported were newly found. While four types resulted in amino acid change, the others were silent mutations. CONCLUSIONS: Although it is not clear that the relationship of these newly found mutations with INH resistance, they show marked diversity in Korean MDR-TB strains. It also suggests their feasibility as a molecular target to supplement determining the INH resistance of clinical isolates because of the possible existence of low-level INH resistant strains.
Amino Acid Substitution ; Animals ; Codon ; DNA ; Ecthyma, Contagious ; Isoniazid ; Mycobacterium tuberculosis ; Point Mutation ; Polymerase Chain Reaction ; Promoter Regions, Genetic ; Tuberculosis*

Mycobacterium genavense, first identified in 1990, is known as a pathogen that mimics disseminated Myocobacterium avium-intracellulare complex (MAC) infection with particular propensity for the gastrointestinal tract. In Korea, no case with the organism has been reported. Herein we report a case of Mycobacterium genavense infection that manifested with erosive lesion of duodenum in a patient with acquired immune deficiency syndrome. The patient presented with epigastric pain and fever, diarrhea. Duodenal biopsy showed histiocytic infiltration with numerous acid-fast bacilli. Identification of the mycobacterial isolate by the polymerase chain reaction restriction analysis of 16S rRNA gene revealed Mycobacterium genavense.
Acquired Immunodeficiency Syndrome ; Biopsy ; Diarrhea ; Duodenum* ; Fever ; Gastrointestinal Tract ; Genes, rRNA ; HIV Infections* ; HIV* ; Humans ; Korea ; Mycobacterium* ; Polymerase Chain Reaction

Mycobacterium genavense, first identified in 1990, is known as a pathogen that mimics disseminated Myocobacterium avium-intracellulare complex (MAC) infection with particular propensity for the gastrointestinal tract. In Korea, no case with the organism has been reported. Herein we report a case of Mycobacterium genavense infection that manifested with erosive lesion of duodenum in a patient with acquired immune deficiency syndrome. The patient presented with epigastric pain and fever, diarrhea. Duodenal biopsy showed histiocytic infiltration with numerous acid-fast bacilli. Identification of the mycobacterial isolate by the polymerase chain reaction restriction analysis of 16S rRNA gene revealed Mycobacterium genavense.
Acquired Immunodeficiency Syndrome ; Biopsy ; Diarrhea ; Duodenum* ; Fever ; Gastrointestinal Tract ; Genes, rRNA ; HIV Infections* ; HIV* ; Humans ; Korea ; Mycobacterium* ; Polymerase Chain Reaction

A total of 190 ticks collected from the Chungju area of Korea was examined for the presence of Spotted Fever Group(SFG) Rickettsia using a PCR assay. Twenty-five (13.2%) Haemaphysalis ticks were found positive of the groEL gene of SFG Rickettsia. The prevalence rate of R. japonica in these 25 Haemaphysalis ticks was 72% (18 out of 25 SFG Rickettsia). The prevalence rate of R. conorii and new SFG rickettsia in these 25 Haemaphysalis ticks was 4% (1 out of 25 SFG Rickettsia) and 24% (6 out of 25 SFG Rickettsia), respectively. These results suggest that R. japonica was the highest infection frequency among in Haemaphysalis ticks SFG Rickettsia, and that R. conorii and new SFG Rickettsia are also present in the Chungju area.
Chungcheongbuk-do* ; Fever* ; Korea ; Polymerase Chain Reaction ; Prevalence* ; Rickettsia* ; Ticks*