• Journal of Yeungnam Medical Science
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• v.41 no.2
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• pp.113-119
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• 2024

Background: Missing isoniazid (INH) resistance during tuberculosis (TB) diagnosis can worsen the outcomes of INH-resistant TB. The BD MAX MDR-TB assay (BD MAX) facilitates the rapid detection of TB and INH and rifampin (RIF) resistance; however, data related to its performance in clinical setting remain limited. Moreover, its effect on treatment outcomes has not yet been studied. Methods: We compared the performance of BD MAX for the detection of INH/RIF resistances to that of the line probe assay (LPA) in patients with pulmonary TB (PTB), using the results of a phenotypic drug sensitivity test as a reference standard. The treatment outcomes of patients who used BD MAX were compared with those of patients who did not. Results: Of the 83 patients included in the study, the BD MAX was used for an initial PTB diagnosis in 39 patients. The sensitivity of BD MAX for detecting PTB was 79.5%. The sensitivity and specificity of BD MAX for INH resistance were both 100%, whereas these were 50.0% and 95.8%, respectively, for RIF resistance. The sensitivity and specificity of BD MAX were comparable to those of LPA. The BD MAX group had a shorter time interval from specimen request to the initiation of anti-TB drugs (2.0 days vs. 5.5 days, p=0.001). Conclusion: BD MAX showed comparable performance to conventional tests for detecting PTB and INH/RIF resistances. The implementation of BD MAX as a diagnostic tool for PTB resulted in a shorter turnaround time for the initiation of PTB treatment.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.811-818
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• 1999

A total of 16 Staphylococcus epidermidis isolates collected from 14 dogs admitted to the Veterinary Medicial Teaching Hospital in Seoul National University over eleven months were examined for in vitro antibiotic susceptibility pattern with minimum inhibitory concentration (MIC) and slime production, a virulence-associated phenotype, and were genetically characterized by pulsed-field gel electrophoresis (PFGE). The frequency of resistance to antimicrobial agents tested was not high, with a susceptibility ranging from 56.3% to 100%. Three strains exhibited multiple drug resistance against amikacin (MIC, $32-64{\mu}g/ml$), ampicillin ($32{\mu}g/ml$), fosfomycin ($32-128{\mu}g/ml$) and gentamicin ($16{\mu}g/ml$). Vancomycin, ciprofloxacin and rifampin were effective antibiotics against the isolates. All isolates were slime producers ; strains isolated from dogs which died of bacteremia were more likely to produce slime than those isolated from dogs which survived. Chromosomal DNA fingerprinting of the isolates yielded 16 different genomic types with few common bands, indicating a variety of clones of S epidermidis were prevalent in the hospital. This study revealed that PFGE is an useful method for the genotype characterization of S epidermidis strains and this organism could probably be pathogenic in some dogs with severe disorders. Further works on a larger number of epidemiologically defined strains are required to assess these results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.850-857
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• 2022

Seventy-five Vibrio parahaemolyticus isolates from the surface seawater of the Geum River Estuary area, on the west coast of Korea, were analyzed for the presence of virulence genes and susceptibility to 17 different antimicrobials. All 75 isolates were examined for the presence of two virulence genes (tdh or trh) using polymerase chain reaction; Only one of the isolates possessed the tdh or trh gene. According to the results of disk diffusion susceptibility tests, all of the strains were resistant to penicillin G, 92.0% were resistant to ampicillin, 82.7% were resistant to amoxicillin, 2.7% were resistant to ciprofloxacin, 2.7% were resistant to trimethoprim, 1.3% were resistant to cephalothin, and 1.3% were resistant to erythromycin. However, all of the strains were susceptible to amikacin, cefoxitin, chloramphenicol, gentamycin, kanamycin, nalidixic acid, nitrofurantoin, rifampin, streptomycin, and tetracycline. The average minimum inhibitory concentrations for ampicillin for V. parahaemolyticus was 557.6 ㎍/mL. These results not only provide novel insight into the necessity for seawater sanitation in Geum river estuary area, but they help reduce the risk of contamination of antimicrobial-resistant bacteria.

• Tuberculosis and Respiratory Diseases
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• v.74 no.6
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• pp.251-255
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• 2013

Tuberculosis (TB) is one of the largest health problems in the world today. And the incidence of nontuberculous mycobacteria (NTM) lung disease appears to be increasing worldwide. Recently, an automated, nucleic acid amplification assay for the rapid detection of both Mycobacterium tuberculosis and rifampin resistance was developed (Xpert MTB/RIF). And fixed-dose combinations of anti-TB drugs and linezolid have been introduced in the treatment of TB. And new NTM species, named Mycobacterium massiliense, which is very closely related to Mycobacterium abscessus was reported. In this review, these recent advances in the diagnosis and treatment of TB and clinical characteristics of M. massiliense lung disease are discussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.564-572
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• 2016

In this study, we isolated and characterized Escherichia coli from mussels and inland pollution sources in or in proximity to the Changseon area on the southern coast of Korea in 2014. A total of 147 strains of E. coli were isolated from 54 mussels and 32 pollution-source samples. The susceptibility of the isolates to 24 antimicrobial agents was analyzed. The resistance of E. coli isolates to rifampin was highest at 100%, followed by cephalothin (98.6%), tetracycline (91.8%), amikacin (81.0%), ampicillin (79.6%), cefazolin (79.6%), streptomycin (73.5%), piperacillin (70.7%), gentamicin (37.4%), cefoxitin (35.4%), cefamandole (34.7%), tobramycin (29.9%), amoxicillin/clavulanic acid (24.5%), nalidixic acid (21.8%), trimethoprim (19.0%), chloramphenicol (17.7%), cefotaxime (12.9%), trimethoprim (10.9%), ceftazidime (10.2%), aztreonam (7.5%), imipenem (2.7%), cefepime (2.0%), and cefotetan (0.0%). In addition, the antimicrobial resistance of E. coli isolates from inland pollution sources was slightly greater than or similar to that of isolates from mussels.

• Korean Journal of Veterinary Service
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• v.47 no.1
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• pp.27-33
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• 2024

At the present study, it was aimed to explore the states of antimicrobial resistant Staphylococcus aureus isolates from 1,360 chickens, pigs and cattle carcass (400 chickens, 480 pigs and 480 cattle) in Daegu province from January 2022 to December 2022. Among 1,360 samples, 81 of S. aureus were isolated cattle (1.4%), pigs (7.7%) and chickens (9.2%). In antimicrobial susceptibility test, all of the isolates were demonstrated susceptibility to rifampin. But the isolates were showed resistance other antibiotics in order of tetracycline (62.9%), ciprofloxacin (62.9%), tobramycin (58.0%), gentamicin (51.8%), amikacin (40.7%), penicillin (39.5%), clindamycin (35.8%), enrofloxacin (33.3%), trimethoprim/sulfamethoxazole (30.8%), oxacillin (30.8%), minocycline (29.6%), erythromycin (25.9%), quinupristin/dalfopristin (20.9%), chloramphenicol (12.3%), cefoxitin (9.8%). Among the 81 S. aureus isolates, 25 (30.8%) methicillin-resistant staphylococcus aureus (MRSA) were observed. Seven (28.0%) of 25 MRSA harbored mecA gene. About 96% of MRSA were multidrug resistance to at least 3 more drugs. A continuous monitoring and surveillance program to prevent antimicrobial resistance in livestock products is demanded.

• Tuberculosis and Respiratory Diseases
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• v.43 no.6
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• pp.862-870
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• 1996

Background : Multidrug-resistant tuberculosis(MDR-Tb) has been increased not only in Asia but also in Western society, which may cause public health problems and reduce the efficacy of treatment of tuberculosis. In Western society HIV infection is believed to do a central role in increasing incidence of MDR tuberculosis, but MDR-Tb in Korea may be somewhat different about clinical features, underlying disorders, and prognosis. Goble et al reponed that overall treatment failure rate in MDR-Tb including resistance to isoniazid(INH) and rifampin (RFP) was 44 %. The aim of this study is to find the treatment result in Korea and the factors determining the prognosis. Methods: A retrospective study of pulmonary tuberculosis cultured M. tuberculosis from sputum or bronchial washing fluid between 1986 through 1992 was conducted in the Seoul Paik Hospital, Inje University. We reviewed clinical courses of 141 patients, who had a tuberculosis with resistance to 2 or more drugs including isoniazid(INH) and rifampin(RFP). One hundred and 4 patients of 141 patients had completed treatment and followed up for more than one year. Results: Of 104 (mean age $43.6{\pm}16.7$, M: F=63 : 41) patients with sufficient follow-up data, 73(84.6%) patients responded which is defined as negative Sputum cultures for at least 3 consecutive months. Seven patients(6.7%) had a failure in negative conversion and 9(8.7%) of the patients who initially responded relapsed. Overall treatment failure rate was 15.4%, Patients who were treated for less than 12 months had a higher relapse rate(12.3%) than 18 months(4.9%). And there was a statistically significant correlation between the relapse rate and the number of drugs to which isolates wera resistant(p<0.05). Conclusion : The treatment failure rate of MDR-Tb in Korea was lower than previous studies in western Country and the major determining factor of prognosis was the number of resistant drugs to M. tuberculosis at drug sensitivity test. For reducing the relapse rate, we recommend more than 12 months of treatment for MDR tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.64 no.2
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• pp.95-101
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• 2008

Background: Drug resistant tuberculosis (TB) in patients who have not received previous TB treatment (initial drug resistance) is a serious problem for the control of TB. However, prevalence of initial drug resistance among pulmonary TB patients has not been well characterized in Korea, especially in the private sector. We assessed the prevalence of initial drug resistance and evaluated the risk factors for drug resistance in pulmonary TB patients, at a regional tertiary hospital in Cheonan. Methods: We performed a drug susceptibility test for both first and second line anti-TB drugs in all culture-confirmed pulmonary TB patients who had not received a previous TB treatment at Dankook University Hospital from September 2005 to September 2007. In addition, we evaluated the initial drug resistance pattern and clinical characteristics of patients to evaluate the risk factors for initial drug resistance. We also assessed the influence of the drug susceptibility test results on the treatment regimen. Results: Of the total 156 cases where the drug susceptibility test was performed, resistance to at least one anti-TB drug was found in 21 cases (15.6%) and multidrug resistance, where TB was resistant to at least isoniazid and rifampin, was found in one case (0.6%). Multivariate logistic regression showed no clinical characteristics were independently associated with initial drug resistance. Of the total 156 patients who underwent the drug susceptibility test, the treatment regimen was changed for 15 patients (9.6%) according to the results of the drug susceptibility test. Conclusion: Initial drug resistance is common and the drug susceptibility test is informative for pulmonary TB patients who have not received previous TB treatment.

• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.243-247
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• 2005

Background : The prevalence of tuberculosis is slowly decreasing in Korea. However, the drug-resistance of pulmonary tuberculosis is a major risk factor of treatment failure. Moreover, the National Surveillance System has recently been discontinued. Therefore, a continuous survey is necessary for the exact detection of the rate of drug resistance. We studied the recent 4-year drug resistance rate of tuberculosis at a single University hospital in Seoul. Materials and Methods : The study included 239 pulmonary tuberculosis patients performed with a tuberculosis culture and a drug-sensitivity test at Hanyang University Medical Center from March 1999 to March 2003. Results : Of the 239 patients included in the study during the 4-year period, 52 patients showed resistance to one or more anti-tuberculosis drug (21.8%). The rate of multi-drug resistance was 12.6%. The resistance rates to isoniazid, rifampin, ethambutol, streptomycin and pyrazinamide were 18.4%, 13.8%, 11.7%, 6.7% and 8.4%, respectively. Ninety patients had a history of previous anti-tuberculosis treatment, and the rates of the overall drug resistance and multi-drug resistance of these patients were 36.7% and 25.6%, respectively. The patients with drug-resistance showed a higher rate of a previous tuberculosis treatment history (63.5%) than the drug-sensitive group patients (30.5%). Conclusion : The rate of drug resistant tuberculosis is 21.8%, and multi-drug resistant tuberculosis is 12.6%. The rate of drug resistance is higher in those previously treated for tuberculosis.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.251-258
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• 1987

A total of 58 strains of Enterobacter species isolated from clinical specimens at Kyungpook National University Hospital in Taegu and Yonsei University Hospital in Seoul were tested for the molecular characterization to investigate the nosocomial infection through the study of R plasmids which might spread among Gram negative organisms regardless of their originated strains. All strains resistant to ampicillin, cefoxitin and cephalothin but susceptible to moxalactam were subjected to the further test for the determination of in detail MIC value against 23 drugs of common use including beta-lactam antibiotics and R plasmid profile analysis. The reistance frequency of strains against carbenicillin (53.4%) was similar to those against chloramphenicol, tobramycin, and sulfisomidine. Though the MIC values of resistance criteria against ceftazidime, aztreonam, imipenem, and norfloxacine in NCCLS manual were not available but MIC ranges of strains tested were very low. There were differences in patterns and frequencies of resistance between the strains isolated in Seoul and Taegu isolates. Seoul isolates showed a tendency of higher multiplicity of resistance than those of Taegu isolates. The resistances against cefoxitin, cephalothin, cefoperazone, cefotaxime, nalidixic acid, and rifampin were not conferred to the conjugally transferable R plasmid. The approximate molecular size of conjugally transferable R plasmids ranged 30 to 151 megadalton, and one or 2 to 3 R plasmids were identified in each transconjugants.