• Biomedical Science Letters
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• v.19 no.4
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• pp.330-337
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• 2013

There are several methods currently being used to diagnose tuberculosis in patients, such as smear, PCR, tuberculosis culture and X-ray. For a proper medical treatment, antimicrobial susceptibility test and rapid drug susceptibility testing have been operated. Tuberculosis bacilli usually need 3~8 weeks of culture period because of delay in RNA synthesis and require 15~22 hours for generation. After a germ raises in culture, we initiated antimicrobial susceptibility test for a proper treatment. It has some difficulties to give a proper prescription for a tuberculosis patient because antimicrobial susceptibility test requires 4 weeks. To supplement this, we are practicing drug susceptibility testing which allow us to know the sensibility of RMP and INH after 2 or 3 days. But this is only possible when more than 2 positive germ. Therefore, we should practice rapid drug susceptibility testing with culture test. But if media is contaminated by other germs except Mycobacterium tuberculosis, it's hard to interpret result about culture test and to practice antimicrobial susceptibility test and rapid drug susceptibility testing. Because we have to practice again smear, culture test after extracting specimen from the patient, time is consumed and proper patient treatment is postponed. To address these problems and quick patient treatment, rapid drug susceptibility testing is practiced by using GenoType$^{(R)}$ MTDRplus method. As a result of this method we detected sensibility 10 and 7 cases and resistance 0 and 3 cases using RIM and INH respectively with other 1 case toward medicals out of the total 11 test. In conclusion rapid drug susceptibility testing can be used from the contaminated specimen after elimination of contaminated source from culture and proved that it can be practiced for rapid examination of a tuberculosis patient.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.227-239
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• 2022

Purpose: In our study, in order to find lactic acid bacteria (LAB) with multi-drug resistance to antibiotics, we isolated 140 strains from 15 types of kimchi commercially available in Korea and 20 types of Kimchi made at home from January to December in 2016, and investigated their H₂O₂ generating ability and multi-drug resistance to antibiotics. Methods: In order to observe the H₂O₂ generation ability of LAB, we performed the experiment with methods such as Rabe, Hillier, and Kang. To test the antibacterial susceptibility of LAB, we used the disc agar diffusion method using MRS agar (Difco, USA) according to the CLSI and WHO test methods. There are 18 types of antibiotic discs used. Results: Out of the total numbers of 140 strains, 6 strains of Ent. Faecium, 25 strains of L. plantarum, 1 strain of L. rhamnosus, 3 strains of L. sakei, 1 strain of L. acidophilus, 1 strains St. thermophilus, and 7 of unidentified strains generated H₂O₂. The antibiotic susceptibility of Ent. Faecium indicated SXT, OX, NA, and E; and the antibiotic susceptibility of L. plantarum indicated NA; and the antibiotic susceptibility of St. thermophilus indicated NA, CC, RA, CTT, CM, and P ; and the antibiotic susceptibility of L. rhamnosus indicated SXT, VA, NA and CTT; and the antibiotic susceptibility of 6 strains of L. sakei indicated SXT, OX, NOR, NA, CTT and CIP, all indicating antibiotic resistance. In the case of multi-drug resistance to antibiotics for 53 strains of L. antarum, 8-drug resistance was the most common with 25 strains, followed by 7-drug-resistant strains with 18 strains, 9-drug-resistant strains with 4 strains, 6-drug-resistant strains with 3 strains, 5-drug-resistant strains with 2 strains, and 17-drug-resistant strains with 1 strain. In the case of multi-drug resistance to antibiotics for Ent. Faecium 27 strains, 9-drug resistance was most commonly identified as 9 strains, 8-drug resistance was identified as 6 strains, 7- and 11 drug resistances were identified as 4 strains each, and 4- and 6-drug resistances were identified as 1 strain each. Conclusion: Ent. Faecium, L. plantarum, L. rhamnosus, L. sakei, and St. thermophilus, shown to have anantibacterial activity in previous studies on LAB and shown to have and H₂O₂ generating ability, antibiotic resistance and multi-drug resistance in this study, are expected to be able to play an excellent role for long-term inpatients to use as an alternative to antibiotics and to cope with emerging antibiotic resistance.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.685-689
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• 2000

Due to the uncultivable nature of Mycobacterium leprae in vitro, the fast, easy, and accurate measurement of the antimicrobial drug susceptibility of this microbe has been difficult. Conventional methods for such testing are subjective, cumbersome, and expensive in some cases. Here, the utility of a reverse transcriptase-PCR (RT-PCR)-based assay for testing was examined and compared with a Buddmeyer-type radiorespirometric assay. The susceptibility of M. leprae to rifampin was determined by probing the presence of M.leprae-specific 18 kDa gene mRNA in M. leprae-infected IC-21 macrophage cells after drug treatment. The results showed that, as the refampin concentration was increased, the 360-bp cDNA products generated by the RT-PCR-based assay decreased in a dose-dependent manner as in the drug susceptibility observed in the Buddmeyer-type assay. The drug susceptibility testing of M. leprae by the RT-PCR based assay was found to be not only faster but also nearly $10^4$-fold more sensitive than the Buddmeyer-type assay. Moreover, it was also found that, unlike the RT-PCR based assay, the same testing by a DNA-PCR resulted in no differences in the 360-bp signal, regardless of the rifampin concentrations used. Accordingly, these results demonstrated that the drug susceptibility of M. leprae can be determined effectively by an RT-PCR-based assay, thereby providing a new, fast, and sensitive testing method.

• 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.

• Korean Journal of Veterinary Service
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• v.15 no.1
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• pp.81-88
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• 1992

This study was conducted to determine the microorganisms inhabitating in sow genital organs and their anti-microbial drug susceptibility During the period between February, 1991 and November 1991, 128 sow genital organs were sampled at six abattoirs. Gross pathological examination and bacterial isolation and identification were performed from the genital organ. In addition, antimicrobial drug susceptibility for the major organisms isolated were examined. 1. Among the bateria isolated from normal genital organs, E. coli(30.7%) Stahylococcus spp.(29.4%), Corynebarterium pyogenes(C. pyogenes) (14.7%), Streptococcus spp.(13.3%) were most freqently isolated, whereas the genera of Klebsiella, Actinobacillus, and Serratia were detected less freqently. 2. Among the bacteria isolated from abnormal genital organs, C. pyogenes,(37.7%), Stahylococcus spp.(30.2%), Proteus spp. (26.4%) , Pasteurella spp. (18.9%) , Steptococcus spp. (9.4%) were most freqently isolated whereas the genera of Pseudomonas, Serratia and Klebsiella were detected less freqently. 3. From sow genital organs showing lesion of endometritis and purulent endometritis C. pyogenes were most freqently isolated, the isolation rate being 67.7％ and followed by Stahylococcus spp., E. coli, Proteus spp., Steptococcus spp. and Pasteurella spp. in the order. 4. Antimicrobial drug susceptibility of the major organisms showed that all the isolates were susceptible to cephalothin, ampicillin, chloramphenicol and sulfamethoxazole / trimethoprim, but resistant to penicillin and streptomycin.

• Tuberculosis and Respiratory Diseases
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• v.85 no.3
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• pp.256-263
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• 2022

Background: Mycobacterium tuberculosis (Mtb) is resistant to the β-lactam antibiotics due to a non-classical transpeptidase in the cell wall with β-lactamase activity. A recent study showed that meropenem combined with clavulanate, a β-lactamase inhibitor, was effective in multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB). However, in Korea, clavulanate can only be used as drugs containing amoxicillin. In this study, we investigated the susceptibility and genetic mutations of drug-resistant Mtb isolates to amoxicillin-clavulanate and meropenem-clavulanate to improve the diagnosis and treatment of drug-resistant TB patients. Methods: The minimum inhibitory concentration (MIC) of amoxicillin-clavulanate and meropenem-clavulanate was examined by resazurin microtiter assay. We used 82 MDR and 40 XDR strains isolated in Korea and two reference laboratory strains. Mutations of drug targets blaC, blaI, ldtA, ldtB, dacB2, and crfA were analyzed by polymerase chain reaction and DNA sequencing. Results: The MIC₉₀ values of amoxicillin/clavulanate and meropenem/clavulanate in drug-resistant Mtb isolates were 64/2.5 and 16/2.5 mg/L, respectively. Gene mutations related to amoxicillin/clavulanate and meropenem/clavulanate resistance could not be identified, but T448G mutation was found in the blaC gene related to β-lactam antibiotics' high susceptibility. Conclusion: Our results provide clinical consideration of β-lactams in treating drug-resistant TB and potential molecular markers of amoxicillin-clavulanate and meropenem-clavulanate susceptibility.

• Clinical and Experimental Pediatrics
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• v.52 no.5
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• pp.529-537
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• 2009

Drug-resistant tuberculosis in children has important implications for both the patients and tuberculosis control programs. In Korea, among all new patients, the isoniazid resistance rate was 9.9% and multidrug-resistant tuberculosis rate was 2.7% in 2004 (in patients aged 10-19 yr, the multidrug-resistant tuberculosis rate reached 2.1%). Tuberculosis in pediatric patients is difficult to diagnose because many children have nonspecific clinical signs and the detection rates of acid-fast bacilli smears and cultures are low. Therefore, every effort should be made to identify adult sources and obtain information on drug susceptibility because symptomatic adult patients have a higher chance of culture positivity and drug-susceptibility patterns are the same in most adult-child pair patients. Korean children are at significant risk of drug-resistant tuberculosis. As the isoniazid resistance rate is greater than 4% among the new cases in Korea, a four-drug regimen should be considered for initial treatment of children with active tuberculosis, unless drug-susceptibility test results are available. Treatment of drug-resistant tuberculosis in children is challenging and there are only few available data. Tuberculosis control programs should be continuous with specific focus on pediatric populations because they can serve as reservoirs for future active cases. Further studies are needed regarding treatment of drug-resistant tuberculosis in children.

• Biomedical Science Letters
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• v.22 no.4
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• pp.215-219
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• 2016

The problems of tuberculosis and its drug resistance are very severe. Therefore, rapid and accurate drug susceptibility assay is required. Recently, there has been an increased understanding of the genetic mechanism of Mycobacterium tuberculosis (MTB) drug resistance as well as advancement of molecular technologies. While many gene mutations correlate well with drug resistance, many genes do not show a strong correlation with drug resistance. For this reason, the current study assessed the utility of rpoB mRNA as a target to detect live mycobacteria. In this study, RT-PCR targeting of rpoB mRNA in BCG treated with rifampin was performed. Conventional RT-PCR and real-time PCR targeting rpoB mRNA as well as 85B mRNA was performed to determine whether these two methods could distinguish between viable and non-viable MTB. The levels of rpoB and 85B mRNA detected by RT- PCR were compared in parallel with colony forming unit counts of BCG that were treated with rifampin for different periods of time. The data suggests that that even though both mRNA levels of rpoB and 85B decreased gradually when rifampin-treatment increased, the rpoB mRNA seemed to represent live bacteria better than 85B mRNA. This study clearly indicates that RT-PCR is a good method to monitor viable cell counts in the liquid culture treated with the anti-tuberculosis drug.

• Journal of Veterinary Clinics
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• v.20 no.2
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• pp.177-184
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• 2003

The present study was conducted to investigate isolation and antimicrobial drug susceptibility of clinical mastitic milking total 610 (897 quaters) dairy cattles from 36 dairy farms in Gyeongnam south area (Cosung, Masan) during the period from March 1999 to August 2002. The results obtained were summerized as follows . 1. Incidence of bacterial infection in four quaters was showed that right anterior quarter was 178(19.8%), right posterior quarter was 292(32.6%), left anterior quarter was 148 (16.2%), and left posterior quarter was 279 (31.1%), respectively. Isolation rate of posterior two quarters was higher 2 times than anterior two quarters. 2. Incidence of double infections of 897 clinical mastitic milk were showed that single infection was 549 (61.2%), double infection was 167(18.6%), triple infection was 9(1%) and no isolation was 172(19.2%). 3. Isolation of infected etiologic bacteria was showed that Streptococci spp., was 267(31%), Staphylococci spp., was 267(41%), S aureus, was 48(5.6%), G(-) bacillus was 126(5.6%), and Corynebactrium spy. was 52(6%), respectively, from total 861 samples. 4. The results of antimicrobial drug susceptibility of all isolates were showed that Streptococci spp., Staphylococci spp., S aureus, (G)(-) bacillus, and Corynebactrium spp. were susceptible to cefuroxime, cefoperazone, amoxicillin, cefazolin, ampicilin, penicillin, gentamicin, erythromycin, cloxacilin, ciprofloxacin, sulfamethoxasole/trimetoprim, teteracyclin, and norfloxacin (> 70%), but some of them were resistant to neomycin, streptomycin colistin, and cephalothin(> 60). 5. The results of drug susceptibility obtained from each farms had different susceptibility, even though, etiological microorganisms were same in each farms.

• Tuberculosis and Respiratory Diseases
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• v.79 no.4
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• pp.282-288
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• 2016

Background: Tuberculosis (TB) is a major health problem, and accurate and rapid diagnosis of multidrug-resistant (MDR) and extended drug-resistant (XDR) TB is important for appropriate treatment. In this study, performances of solid and liquid culture methods were compared with respect to MDR- and XDR-TB isolate recovery and drug susceptibility testing. Methods: Sputum specimens from 304 patients were stained with Ziehl-Neelsen method. Mycobacterium tuberculosis (Mtb) isolates were tested for recovery on $L{\ddot{o}wenstein$-Jensen (LJ) medium and the BacT Alert 3D system. For drug susceptibility testing of Mtb, isolates were evaluated on M-KIT plates and the BacT Alert 3D system. Results: The recovery rates were 94.9% (206/217) and 98.2% (213/217) for LJ medium and the BacT Alert 3D system, respectively (kappa coefficient, 0.884). The rate of drug resistance was 13.4% for at least one or more drugs, 6.0% for MDR-TB and 2.3% for XDR-TB. M-KIT plate and BacT 3D Alert 3D system were comparable in drug susceptibility testing for isoniazid (97.7%; kappa coefficient, 0.905) and rifampin (98.6%; kappa coefficient, 0.907). Antibiotic resistance was observed using M-KIT plates for 24 of the total 29 Mtb isolates (82.8%). Conclusion: The liquid culture system showed greater reduction in the culture period, as compared with LJ medium; however, drug susceptibility testing using M-KIT plates was advantageous for simultaneous testing against multiple drug targets.