• Tuberculosis and Respiratory Diseases
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• 제83권1호
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• pp.20-30
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• 2020

Tuberculosis (TB) remains a threat to public health and is the leading cause of death globally. Isoniazid (INH) is an important first-line agent for the treatment of TB considering its early bactericidal activity. Resistance to INH is now the most common type of resistance. Resistance to INH reduces the probability of treatment success and increases the risk of acquiring resistance to other first-line drugs such as rifampicin (RIF), thereby increasing the risk of multidrug-resistant-TB. Studies in the 1970s and 1980s showed high success rates for INH-resistant TB cases receiving regimens comprised of first-line drugs. However, recent data have indicated that INH-resistant TB patients treated with only firs-tline drugs have poor outcomes. Fortunately, based on recent systematic meta-analyses, the World Health Organization published consolidated guidelines on drug-resistant TB in 2019. Their key recommendations are treatment with RIF-ethambutol (EMB)-pyrazinamide (PZA)-levofloxacin (LFX) for 6 months and no addition of injectable agents to the treatment regimen. The guidelines also emphasize the importance of excluding resistance to RIF before starting RIF-EMB-PZA-LFX regimen. Additionally, when the diagnosis of INH-resistant TB is confirmed long after starting the first-line TB treatment, the clinician must decide whether to start a 6-month course of RIF-EMB-PZA-LFX based on the patient's condition. However, these recommendations are based on observational studies, not randomized controlled trials, and are thus conditional and based on low certainty of the effect estimates. Therefore, further work is needed to optimize the treatment of INH-resistant TB.

• 대한수의학회지
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• 제28권2호
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• pp.331-337
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• 1988

This paper dealt with the distribution of Salmonella (S) infection on 4 herds in Kyungju and Taegu during the period from May to October 1986. Isolated Salmonella were examined for serotypes, antimicrobial drug resistance and detection of R plasmid. The results obtained were summarised as followings: 1. Of total 4.622 samples from 4 herds, 67 Salmonella were isolated from 51 samples(1.1%), and their serovar strains were S typhimurium 6, S derby 5, S infantis 4, S bareilly 4, S dublin 3, S anatum 2, S montevideo 2 and untypable 41. 2. The isolation rate of Salmonella was higher in summer and autumn. 3. Of the 67 strains examined, 45 (67.2%) were resistant to one or more antibiotics, such as ampicillin (Am), cephalothin (Ce), chloramphenicol (Cm), rifampicin (Rf), sulfadimethoxine (Su), and tetracycline (Tc), and higher resistant to Sm (40.2%), Ce (31.3%), Am (23.9%). 4. Of the 45 resistant Salmonella strains, 44 (97.8%) harbored conjugative R plasmids and the transfer frequency of Sm (100%), Ce (95.2%), Tc (91.0%) and Su (80.0%) resistance was much higher than that of the other drug resistance. 5. The most common resistant patterns were Sm, Ce, AmCeCmSmSuTc, and AmCe. 6. In 4 herds, the incidience of drug resistance was 57.7%~100% and transfer frequency of conjugative R plasmid was 96.1%~100%.

• 대한수의학회지
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• 제35권3호
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• pp.537-542
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• 1995

In this study, we aim to find the presence of virulence-related plasmid in Salmonella isolates from poultry, and the difference between S pullorum and S gallinarum on the plasmid profile and antibiotics resistance. We used seventeen isolates of Salmonella spp that were isolated from poultry. Thirteen isolates, S typhimurium(ST), S pullorum(SP) and S gallinarum(SG), contained virulence-related plasmids. These are 95Kd plasmid in ST and 85Kd plasmid in SP and SG. Three(1/4 of ST, 1/1 of SE, and 1/9 of SP) isolates have no detectable plasmids. The isolates of ST have relatively variable plasmid profile but the isolates of S pullorum except No 12(additional 3.0Kb plasmid) have common 85K6, 8.1Kb, 4.0Kb and 2.3Kb plasmid and two of three isolates of S gallinarum have common 85Kb, 4.0Kb and 2.3Kb plasmid but the rest has only 85Kb plasmid. Interestingly, all of the isolates of SP have 8.1Kb plasmid, and same size of plasmid is also found in one of ST isolates. All of the isolates have the resistance to penicillin, chloramphenicol, rifampicin, streptomycin, sulfamethazine and some isolates show the resistance to ampicillin and tetracycline. There is no relatedness between plasmid profile and antibiotics resistance and no differences between SP and SG in antibiotics resistance. Therefore further differentiation of each isolates by restriction enzyme assay and, if possible, charaterization of each plasmid, especially, 8.1Kb plasmid in SP and ST, may be necessary.

• Journal of Microbiology and Biotechnology
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• 제16권8호
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• pp.1276-1284
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• 2006

Listeria monocytogenes is a well-known high-risk foodborne pathogen that grows at refrigeration temperature and is responsible for outbreaks of listeriosis. We report here the incidence of L. monocytogenes in fresh chicken carcasses and present genetic diversity of L. monocytogenes isolates. In this study, 25 g of chicken carcasses from markets in Korea were examined according to the FDA method, and presumptive isolates were confirmed by multiplex PCR assay. L. monocytogenes isolates were analyzed by Pulsed-Field Gel Electrophoresis using restriction enzymes, ApaI and AscI, to obtain strain-specific DNA fragments profiles. Antimicrobial resistance of L. monocytogenes strains against generally used antibiotics (Penicillin G, Kanamycin, Tetracycline, Vancomycin, Cephalothin, Rifampicin, Erythromycin, Ampicillin, Gentamicin, Streptomycin, and Chloramphenicol) were analyzed by NCCLS protocols to examine the presence of antimicrobial resistance in natural L. monocytogenes. Of a total 274 chicken samples, 81 samples (29.6%) were positive for L. monocytogenes. Listeria innocua (50.1%), Listeria welshimeri (6.9%), and Listeria grayi (11.3%) were also detected. PFGE analysis, using restriction enzymes ApaI and AscI, showed 27 pulsotypes of L. monocytogenes. Antimicrobial resistance analysis confirmed the existence of antimicrobial resistance for penicillin G and tetracycline in isolated L. monocytogenes strains.

• 미생물학회지
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• 제30권4호
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• pp.260-264
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• 1992

2, 4, 5-T 분해균주인 Pseudomonas sp. EL-071P 는 rifampicin, ampicilin, kanamycin 등의 중금속에 대하여 내성을 가지고 있었다. 이 균주로부터 2, 4, 5-T 분해능과 rifampicin 의 내성에 관련된 하나의 plasmid 를 분리, 정제하였으며 그 크기는 약 40 kb 이었다. E. coli 에 2, 4, 5-T 분해능에 관ㅎ련된 plasmid 를 transformation 한 결과 2, 4, 5-T 분해에는 plasmid 가 관여함을 확인할 수 있었다. 이 균주는 다양한 염소계방향족 동족체화합물을 유일한 탄소원으로 하여 생육할 수 있었으며, chlorophenol compound 의 경우 CI$^{-}$ 의 치환위치가 ortho, para-, meta- 위치순으로 분해가 잘 되었다. 2, 4, 5, -T 의 기질 유사체인 4-chlorophenol 에 의해 2, 4, 5-T 대사가 저해되었다. 비염소계 방향족화합물중 benzoate, salicylate, toluene 은 Pseudomonas sp. EL-071P 와 Pseudomonas putida KCTC 1643 에 의해 탄소원으로 이용되었으나 naphtalene 의 경우 Pseudomonas sp. EL-071 에 의해서만 탄소원으로 이용되어 표준균주인 Pseudomonas putida KCTC 1643 과 상이한 결과를 나타내었다.

• Journal of Yeungnam Medical Science
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• 제37권4호
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• pp.277-285
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• 2020

Tuberculosis (TB) is still a major health problem worldwide. Especially, multidrug-resistant TB (MDR-TB), which is defined as TB that shows resistance to both isoniazid and rifampicin, is a barrier in the treatment of TB. Globally, approximately 3.4% of new TB patients and 20% of the patients with a history of previous treatment for TB were diagnosed with MDR-TB. The treatment of MDR-TB requires medications for a long duration (up to 20-24 months) with less effective and toxic second-line drugs and has unfavorable outcomes. However, treatment outcomes are expected to improve due to the introduction of a new agent (bedaquiline), repurposed drugs (linezolid, clofazimine, and cycloserine), and technological advancement in rapid drug sensitivity testing. The World Health Organization (WHO) released a rapid communication in 2018, followed by consolidated guidelines for the treatment of MDR-TB in 2019 based on clinical trials and an individual patient data meta-analysis. In these guidelines, the WHO suggested reclassification of second-line anti-TB drugs and recommended oral treatment regimens that included the new and repurposed agents. The aims of this article are to review the treatment strategies of MDR-TB based on the 2019 WHO guidelines regarding the management of MDR-TB and the diagnostic techniques for detecting resistance, including phenotypic and molecular drug sensitivity tests.

• Tuberculosis and Respiratory Diseases
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• 제77권4호
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• pp.161-166
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• 2014

Since tuberculosis (TB) remains a major global health concern and the incidence of multi-drug resistant (MDR)-TB is increasing globally, new modalities for the detection of TB and drug resistant TB are needed to improve TB control. The Xpert MTB/RIF test can be a valuable new tool for early detection of TB and rifampicin resistance, with a high sensitivity and specificity. Late-generation fluoroquinolones, levofloxacin, and moxifloxacin, which are the principal drugs for the treatment of MDR-TB, show equally high efficacy and safety. Systemic steroids may reduce the overall TB mortality attributable to all forms of TB across all organ systems, although inhaled corticosteroids can increase the risk of TB development. Although fixed dose combinations were expected to reduce the risk of drug resistance and increase drug compliance, a recent meta-analysis found that they might actually increase the risk of relapse and treatment failure. Regarding treatment duration, patients with cavitation and culture positivity at 2 months of TB treatment may require more than 6 months of standard treatment. New anti-TB drugs, such as linezolid, bedaquiline, and delamanid, could improve the outcomes in drug-resistant TB. Nontuberculous mycobacterial lung disease has typical clinical and immunological phenotypes. Mycobacterial genotyping may predict disease progression, and whole genome sequencing may reveal the transmission of Mycobacterium abscessus. In refractory Mycobacterium avium complex lung disease, a moxifloxacin-containing regimen was expected to improve the treatment outcome.

• 한국축산식품학회지
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• 제31권4호
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• pp.513-520
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• 2011

In order to develop a new starter culture for fermented milk, Lactobacillus fermentum LC272 was isolated from raw milk and its physiological characteristics were investigated. The vitamin $K_2$ concentration of L. fermentum LC272 was $184.94{\mu}g/L$ in Rogosa medium and $63.93{\mu}g/L$ in the reconstituted skim milk. The optimum growth temperature for L. fermentum LC272 was determined to be $40^{\circ}C$ and it took 24 h for the pH to reach 5.2 under this condition. L. fermentum LC272 was more sensitive to rifampicin relative of the other 15 different antibiotics tested, and showed most resistance to streptomycin. L. fermentum LC272 showed higher activities to leucine arylamidase and acid phosphatase. It was comparatively tolerant to bile juice and acid and displayed high resistance against Salmonella Typhimurium and Staphylococcus aureus with rates of 82.9 and 86.3% respectively. These results demonstrated that L. fermentum LC272 could be an excellent starter culture for fermented milk with high levels of vitamin $K_2$ production.

• 대한미생물학회지
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• 제17권1호
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• pp.21-34
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• 1982

각종질환(各種疾患)으로 입원(入院)하여 항균제투여(抗菌劑投與)를 받은 환자(患者)와 최근(最近) 1개월간(個月間) 항균제(抗菌劑)를 투여(投與)받지 않은 학생(學生) 각(各) 60명(名)의 대변(大便)을 배양(培養)하여 각각(各各) 121주(株), 합계(合計) 242주(株)의 대장균(大腸菌)을 얻어 12종(種)의 항균제(抗菌제劑)에 대한 내성양상(耐性樣相)을 조사(調査)하였다. 내성빈도(耐性頻度)를 보면 tetracycline에 대(對)한 내성균(耐性菌)이 68.2%로 가장 많았고 streptomycin(Sm) 61.2%, sulfisomidine(Su) 50%, chtoramphenicol(Cm) 40.9%, ampicillin(Ap) 40.1%, carbenicillin(Cb), 39.3%의 순(順)으로 내성균(耐性菌)의 비율(比率)이 낮아졌고 kanafnycin(Km) cephaleridine(Cr) 및 trimethoprim(Tp)에 내성(耐性)인 균(菌)은 약(約) 1/4이었고 nalidixicacid, gentamicin 및 amikacin에는 4주(株)씩 만이 내성(耐性)이고 rifampicin에 내성(耐性)인 균(菌)은 없었다. 환자유래균(患者由來菌)과 학생유래균(學生由來菌)을 비교(比較)하여 보면 Cm, Ap, Km, Cr 또는 Cb 내성(耐性)은 환자유래균(患者由來菌)에서 학생유래균(學生由來菌)보다 월등(越等)히 많았으며 Sm, Su 또는 Tp 내성균(耐性菌)도 다소(多少) 많았으나 기타(其他) 항균제(抗菌劑)에 대(對)한 내성균(耐性菌)에서는 차이(差異)를 볼 수 없었다. 내성균(耐性菌)과 감수성균(感受性菌)에 대(對)한 각(各) 항균제(抗菌劑)의 최소(最少) 발육저지농도(發育阻止濃度)에는 큰 차이(差異)가 있어서 이들 내성(耐性)이 주(主)로 R plasmid에 유래(由來)함을 시사(示唆)하였다. 공시균(供試菌)의 76%가 $1{\sim}10$제(劑) 이상(以上)의 약제(藥劑)에 내성(耐性)이었는데 4제(劑) 이상(以上)의 항균제(抗菌劑)에 내성(耐性)인 균(菌)은 환자유래균(患者由來菌)에서 학생유래균(學生由來菌)에서 보다 많았으며 다약제내성(多藥劑耐性)일수록 환자유래균(患者由來菌)에서 많았다. 2제(劑) 이상(以上)의 항균제(抗菌劑)에 내성(耐性)인 균(菌)에 접합(接合)에 의한 내성전달(耐性傳達)을 145주중(株中) 98주(株)(67.5%)가 내성(耐性)을 전달(傳達)하였으며 7제(劑) 이상(以上)에 내성(耐性)인 균(菌)은 1주(株)를 제외(除外)한 전부(全部)(73주(株))가 그 내성(耐性)을 피전달균(被博達菌)에 전달(傳達)시켰고 다약제내성(多藥劑耐性)의 약제수(藥劑數)가 적을수록 전달성내성(傳達性耐性)을 가진 균(菌)이 적었다. 전달(傳達)되는 내성양상(耐性樣相)은 내성균주(耐性菌株)에 따라 다르며 피전달균(被博達菌)에 따라서도 달랐다. 임의(任意)로 선택(選擇)한 P13균주(菌株)의 R plasmid의 비적합성군(非適合性群)을 보았던바, 이 plasmid는 F II군(群)에 속(屬)함이 판명(判明)되었다. Gel electrophoresis에 의하여 대장균(大腸菌) R plasmid DNA의 형광대(螢光帶)를 증명(證明)할 수 있었다.

• 한국미생물·생명공학회지
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• 제46권2호
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• pp.135-144
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• 2018

The rapid increase in number and diversity of Extended Spectrum ${\beta}$-Lactamases (ESBLs) producing Enterobacteriaceae in natural aquatic environment is a major health concern worldwide. This study investigates abundance and distribution of ESBL producing multidrug resistant Enterobacteriaceae and molecular characterization of ESBL genes among isolates from highly polluted stretch of river Yamuna, India. Water samples were collected from ten different sites distributed across Delhi stretch of river Yamuna, during 2014-15. A total of 506 non duplicate Enterobacteriaceae isolates were obtained. Phenotypic detection of ESBL production and antibiotic sensitivity for 15 different antibiotics were performed according to CLSI guidelines (Clinical and Laboratory Standard Institute, 2015). A subset of ESBL positive Enterobacteriaceae isolates were identified by 16S rRNA gene and screened for ESBL genes, such as $bla_{CTX-M}$, $bla_{TEM}$ and $bla_{OXA}$. Out of 506 non-duplicate bacterial isolates obtained, 175 (34.58%) were positive for ESBL production. Susceptibility pattern for fifteen antibiotics used in this study revealed higher resistance to cefazolin, rifampicin and ampicillin. A high proportion (76.57%) of ESBL positive isolates showed multidrug resistance phenotype, with MAR index of 0.39 at Buddha Vihar and Old Delhi Railway bridge sampling site. Identification and PCR based characterization of ESBL genes revealed the prevalence of $bla_{CTX-M}$ and $bla_{TEM}$ genes to be 88.33% and 61.66%, respectively. Co-occurrence of $bla_{CTX-M}$ and $bla_{TEM}$ genes was detected in 58.33% of the resistant bacteria. The $bla_{OXA}$ gene was not detected in any isolates. This study highlights deteriorating condition of urban aquatic environment due to rising level of ESBL producing Enterobacteriaceae with multidrug resistance phenotype.