Antitubercular Agents/therapeutic use* ; China/epidemiology* ; Drug Resistance, Multiple, Bacterial ; Extensively Drug-Resistant Tuberculosis ; Humans ; Kanamycin Resistance ; Microbial Sensitivity Tests ; Mycobacterium tuberculosis ; Ofloxacin/pharmacology* ; Tuberculosis, Multidrug-Resistant/epidemiology*

BACKGROUND: We examined the feasibility of a full-length gene analysis for the drug resistance-related genes inhA, katG, rpoB, pncA, rpsL, embB, eis, and gyrA using ion semiconductor next-generation sequencing (NGS) and compared the results with those obtained from conventional phenotypic drug susceptibility testing (DST) in multidrug-resistant Mycobacterium tuberculosis (MDR-TB) isolates. METHODS: We extracted genomic DNA from 30 pure MDR-TB isolates with antibiotic susceptibility profiles confirmed by phenotypic DST for isoniazid (INH), rifampin (RIF), ethambutol (EMB), pyrazinamide (PZA), amikacin (AMK), kanamycin (KM), streptomycin (SM), and fluoroquinolones (FQs) including ofloxacin, moxifloxacin, and levofloxacin. Enriched ion spheres were loaded onto Ion PI Chip v3, with 30 samples on a chip per sequencing run, and Ion Torrent sequencing was conducted using the Ion AmpliSeq TB panel (Life Technologies, USA). RESULTS: The genotypic DST results revealed good agreement with the phenotypic DST results for EMB (Kappa 0.8), PZA (0.734), SM (0.769), and FQ (0.783). Agreements for INH, RIF, and AMK+KM were not estimated because all isolates were phenotypically resistant to INH and RIF, and all isolates were phenotypically and genotypically susceptible to AMK+KM. Moreover, 17 novel variants were identified: six (p.Gly169Ser, p.Ala256Thr, p.Ser383Pro, p.Gln439Arg, p.Tyr597Cys, p.Thr625Ala) in katG, one (p.Tyr113Phe) in inhA, five (p.Val170Phe, p.Thr400Ala, p.Met434Val, p.Glu812Gly, p.Phe971Leu) in rpoB, two (p.Tyr319Asp and p.His1002Arg) in embB, and three (p.Cys14Gly, p.Asp63Ala, p.Gly162Ser) in pncA. CONCLUSIONS: Ion semiconductor NGS could detect reported and novel amino acid changes in full coding regions of eight drug resistance-related genes. However, genotypic DST should be complemented and validated by phenotypic DSTs.
Amikacin ; Clinical Coding ; Complement System Proteins ; DNA ; Drug Resistance* ; Ethambutol ; Fluoroquinolones ; Isoniazid ; Kanamycin ; Levofloxacin ; Mycobacterium tuberculosis* ; Mycobacterium* ; Ofloxacin ; Pyrazinamide ; Rifampin ; Semiconductors* ; Streptomycin

Enterococcus spp. are normally present in the gastrointestinal tracts of animals and humans, but can cause opportunistic infections that can be transmitted to other animals or humans with integrated antibiotic resistance. To investigate if this is a potential risk in military working dogs (MWDs), we analyzed antibiotic resistance patterns and genetic relatedness of Enterococcus spp. isolated from fecal samples of MWDs of four different age groups. Isolation rates of Enterococcus spp., Enterococcus (E.) faecalis, and E. faecium, were 87.7% (57/65), 59.6% (34/57), and 56.1% (32/57), respectively, as determined by bacterial culture and multiplex PCR. The isolation rate of E. faecalis gradually decreased with age (puppy, 100%; adolescent, 91.7%; adult, 36.4%; and senior, 14.3%). Rates of resistance to the antibiotics ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole/trimethoprim, imipenem, and kanamycin among Enterococcus spp. increased in adolescents and adults and decreased in senior dogs, with some isolates having three different antibiotic resistance patterns. There were indistinguishable pulsed-field gel electrophoresis patterns among the age groups. The results suggest that Enterococcus is horizontally transferred, regardless of age. As such, periodic surveillance studies should be undertaken to monitor changes in antibiotic resistance, which may necessitate modification of antibiotic regimens to manage antibiotic resistance transmission.
Adolescent ; Adult ; Animals ; Anti-Bacterial Agents ; Ciprofloxacin ; Dogs* ; Drug Resistance, Microbial* ; Electrophoresis, Gel, Pulsed-Field ; Enterococcus faecalis* ; Enterococcus faecium* ; Enterococcus* ; Gastrointestinal Tract ; Gentamicins ; Humans ; Imipenem ; Kanamycin ; Korea* ; Military Personnel* ; Multiplex Polymerase Chain Reaction ; Opportunistic Infections ; Streptomycin

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare but potentially fatal drug-induced systemic hypersensitivity response characterized by erythematous eruption, fever, leukocytosis with eosinophilia, and internal organ involvement. Antitubercular agents are potential causative agents for DRESS syndrome but difficult to verify as a culprit drug, since antitubercular agents are coadministered as a combination regimen. A 42-year-old female with endobronchial tuberculosis was diagnosed with DRESS syndrome after 4-week treatment of isoniazid, rifampicin, ethambutol, and pyrazinamide with prednisolone 50 mg. All the antitubercular agents were stopped and replaced with levofloxacin, cycloserine, p-aminosalicylic acid, and kanamycin. However, severe exacerbation of DRESS syndrome compelled the patient to discontinue the administration of the second-line antitubercular agents. Two months later, the patient underwent a patch test for all the antitubercular agents which had been used, and the results showed positivity to isoniazid and cycloserine. We report a rare case of DRESS syndrome that reacted to cycloserine as well as isoniazid. Development of coreactivity to other drugs should be differentiated with a flare-up reaction in the management of DRESS syndrome.
Adult ; Aminosalicylic Acid ; Antitubercular Agents ; Cycloserine ; Drug Hypersensitivity Syndrome ; Eosinophilia* ; Ethambutol ; Female ; Fever ; Humans ; Hypersensitivity ; Isoniazid ; Kanamycin ; Leukocytosis ; Levofloxacin ; Patch Tests ; Prednisolone ; Pyrazinamide ; Rifampin ; Tuberculosis

We report a case of a 23-year-old female immigrant from China who was diagnosed with multidrug-resistant tuberculosis affecting her lung and brain, resistant to the standard first-line therapeutics and streptomycin. She was treated with prothionamide, moxifloxacin, cycloserine, and kanamycin. However, her headache and brain lesion worsened. After the brain biopsy, the patient was confirmed with intracranial tuberculoma. Linezolid was added to intensify the treatment regimen, and steroid was added for the possibility of paradoxical response. Kanamycin was discontinued 6 months after initiation of the treatment; she was treated for 18 months with susceptible drugs and completely recovered. To our knowledge, this case is the first multidrug-resistant tuberculosis that disseminated to the brain in Korea.
Biopsy ; Brain* ; China ; Cycloserine ; Emigrants and Immigrants ; Female ; Headache ; Humans ; Kanamycin ; Korea ; Linezolid ; Lung ; Mycobacterium tuberculosis ; Prothionamide ; Streptomycin ; Tuberculoma, Intracranial ; Tuberculosis, Central Nervous System ; Tuberculosis, Multidrug-Resistant* ; Tuberculosis, Pulmonary ; Young Adult

Despite global efforts to control tuberculosis (TB), multidrug-resistant TB (MDR-TB) is still a serious problem worldwide. The diagnosis of MDR-TB is based on mycobacterial culture followed by drug susceptibility testing, with results available in weeks to months. This requirement calls for rapid direct tests, especially genotypic tests, in which specimens are amplified directly for the detection of MDR-TB. The treatment of MDR-TB is challenging because of the high toxicity of second-line drugs and the longer treatment duration required compared to drug-susceptible TB. The selection of drugs in MDR-TB is based on the treatment history, drug susceptibility results, and TB drug resistance patterns in each region. Recent World Health Organization guidelines recommend the use of at least four second-line drugs (i.e., a newer fluoroquinolone, an injectable agent, prothionamide, and cycloserine or para-aminosalicylic acid) in addition to pyrazinamide. Kanamycin is the initial choice of an injectable drug, and newer fluoroquinolones include levofloxacin and moxifloxacin. For extensively drug-resistant TB, group 5 drugs such as linezolid and clofazimine need to be included. New drugs such as delamanid and bedaquiline have recently been approved for treating MDR-TB and other agents with novel mechanisms of action that can be given for shorter durations (6-12 months) for MDR-TB are under investigation.
Clofazimine ; Cycloserine ; Diagnosis* ; Drug Resistance ; Fluoroquinolones ; Kanamycin ; Levofloxacin ; Prothionamide ; Pyrazinamide ; Tuberculosis ; Tuberculosis, Multidrug-Resistant* ; World Health Organization

For the treatment of multidrug-resistant (MDR) tuberculosis, maintenance of appropriate antituberculous agents is essential because of its low cure rate and high dropout rate. Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a severe drug-induced systemic hypersensitivity response resulting in cessation of causative agents. In cases of second-line antituberculous agent-induced DRESS, it is extremely difficult to find other replacement medications to cure MDR tuberculosis. A 53-year-old male who had taken the second-line antituberculous agents (cycloserine, streptomycin, p-aminosalicylic acid, and prothionamide) as well as pyrazinamide for 5 weeks experienced DRESS syndrome accompanying hepatic coma. His symptoms improved with discontinuation of antituberculous agents and administration of high-dose methylprednisolone for 1 month. To resume the antituberculous medication, second-line antituberculous agents were administered one by one using a rapid desensitization protocol. While kanamycin, levofloxacin, and cycloserine were successfully readministered, p-aminosalicylic acid- and prothionamide-induced cutaneous hypersensitivity symptoms were relatively mild compared to previous reactions. Herein, we report a case of successfully treated MDR tuberculosis having a history of fatal DRESS syndrome to antituberculous agents using the rapid desensitization protocol.
Aminosalicylic Acid ; Antitubercular Agents ; Cycloserine ; Desensitization, Immunologic ; Drug Hypersensitivity Syndrome* ; Hepatic Encephalopathy ; Humans ; Hypersensitivity ; Kanamycin ; Levofloxacin ; Male ; Methylprednisolone ; Middle Aged ; Patient Dropouts ; Pyrazinamide ; Streptomycin ; Tuberculosis ; Tuberculosis, Multidrug-Resistant

Treatment of multidrug-resistant tuberculosis (MDR-TB) is challenging because of the high toxicity of second-line drugs and the longer treatment duration required compared with drug-susceptible TB. The efficacy of treatment for MDR-TB is poorer than that for drug-susceptible TB. The selection of drugs in MDR-TB is based on previous treatment history, drug susceptibility results, and TB drug resistance patterns in the each region. Recent World Health Organization guidelines recommend the use of least 4 second-line drugs (a newer fluoroquinolone, an injectable agent, prothionamide, and cycloserine or para-aminosalicylic acid) in addition to pyrazinamide. The kanamycin is the initial choice of injectable durgs, and newer fluoroquinolones include levofloxacin and moxifloxacin. For MDR-TB, especially cases that are extensively drug-resistant, group 5 drugs such as linezolid, clofazimine, and amoxicillin/clavulanate need to be included. New agents with novel mechanisms of action that can be given for shorter durations (9-12 months) for MDR-TB are under investigation.
Clofazimine ; Cycloserine ; Drug Resistance ; Extensively Drug-Resistant Tuberculosis ; Fluoroquinolones ; Kanamycin ; Levofloxacin ; Linezolid ; Prothionamide ; Pyrazinamide ; Tuberculosis ; Tuberculosis, Multidrug-Resistant* ; World Health Organization

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is an increasing public health problem and poses a serious threat to global TB control. Fluoroquinolone (FQ) and aminoglycoside (AG) are essential anti-TB drugs for MDR-TB treatment. REBA MTB-FQ(R) and REBA MTB-KM(R) (M&D, Wonju, Korea) were evaluated for rapid detection of FQ and kanamycin (KM) resistance in MDR-TB clinical isolates. METHODS: M. tuberculosis (n=67) were isolated and cultured from the sputum samples of MDR-TB patients for extracting DNA of the bacilli. Mutations in genes, gyrA and rrs, that have been known to be associated with resistance to FQ and KM were analyzed using both REBA MTB-FQ(R) and REBA MTB-KM(R), respectively. The isolates were also utilized for a conventional phenotypic drug susceptibility test (DST) as the gold standard of FQ and KM resistance. The molecular and phenotypic DST results were compared. RESULTS: Sensitivity and specificity of REBA MTB-FQ(R) were 77 and 100%, respectively. Positive predictive value and negative predictive value of the assay were 100 and 95%, respectively, for FQ resistance. Sensitivity, specificity, positive predictive value and negative predictive value of REBA MTB-KM(R) for detecting KM resistance were 66%, 94%, 70%, and 95%, respectively. CONCLUSION: REBA MTB-FQ(R) and REBA MTB-KM(R) evaluated in this study showed excellent specificities as 100 and 94%, respectively. However, sensitivities of the assays were low. It is essential to increase sensitivity of the rapid drug resistance assays for appropriate MDR-TB treatment, suggesting further investigation to detect new or other mutation sites of the associated genes in M. tuberculosis is required.
Chimera ; DNA ; Drug Resistance ; Drug Resistance, Microbial ; Fluoroquinolones ; Humans ; Kanamycin ; Kanamycin Resistance ; Mycobacterium ; Mycobacterium tuberculosis ; Public Health ; Sputum ; Tuberculosis ; Tuberculosis, Multidrug-Resistant

Actinobacillus (A.) pleuropneumoniae is the causative agent of pleuropneumonia which is one of the most important respiratory diseases in pigs worldwide. A total of 32 A. pleuropneumoniae isolates from diseased pigs during 2008 to 2010 were serotyped by polymerase chain reaction method. The susceptibility of the isolates to 13 antimicrobial agents were determined by disk diffusion test. In all the 32 isolates examined in this study, serotype 5 (16 isolates: 50%), 1 (7 isolates: 21.9%), 2 (5 isolates: 15.6%) and 12 (1 isolate: 3.1%) were found. Of all tested antimicrobial agents, resistance to oxytetracycline was found in 96.9% of isolates, followed by resistance to amikacin (81.2%), neomycin (68.7%), kanamycin (53.1%), penicillin (50.0%), gentamicin (43.7%), florfenicol (25.0%), ampicillin (18.7%), colistin (9.4%), trimethoprim/sulfamethoxazole, ceftiofur (8.3%), amoxicillin/clavulanic acid (3.1%) and enrofloxacin (0%). Oxytetracycline or florfenicol-resistant isolates were examined for the presence of resistance gene. Among the 31 oxytetracycline-resistant isolates, tetB, tetH and tetO genes were detected in 22 (71%), 8 (26%) and 1 (3%) isolates, respectively. The floR genes were detected in 8 (100%) of the 8 florfenicol-resistant A. pleuropneumoniae isolates.
Actinobacillus ; Actinobacillus pleuropneumoniae ; Amikacin ; Ampicillin ; Anti-Infective Agents ; Cephalosporins ; Colistin ; Diffusion ; Fluoroquinolones ; Gentamicins ; Kanamycin ; Korea ; Neomycin ; Oxytetracycline ; Penicillins ; Pleuropneumonia ; Polymerase Chain Reaction ; Swine ; Thiamphenicol