• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.149-154
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• 2005

Fifty-one extended-spectrum-${\beta}$-lactamase(ESBL) producing Klebsiella pneumoniae strains were isolated from national university hospitals. All K. pneumoniae strains showed resistance to broad-spectrum antibiotic and most of them presented resistance to amikacin, gentamicin and ciprofloxacin. The results of amplified polymorphic DNA (RAPD) pattern for randomly isolated fifty-one strains were as follows; both twenty-one strains from Chungnam National University hospital and ten strains from Chungbuk National University hospital showed RAPD type Ia and Ib. However, twenty strains isolated from Gyeongsang National University hospital belonged to RAPD type IIa and IIb. All isolates were divided into four molecular types and showed high level of genetic diversity. These results suggested that RAPD analysis provided a rapid and simple method for analysing genotypes of ESBL.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.327-334
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• 2016

Recently, antimicrobial resistance of pathogenic bacteria has been increasing due to excessive use of antimicrobial agents in both humans and livestock. PCR amplification and nucleotide sequence analyses were conducted to investigate16S ribosomal RNA methyltransferase (RMTase) genes and integrons in P. mirabilis strains isolated from clinical specimens and chickens in an area of the Chungcheong providence. In addition, clonality analysis of P. mirabilis strains was performed using a repetitive extragenic palindromic sequence-based PCR (REP-PCR) method. Of the total 38 P. mirabilis isolates, 7 (18.4%) strains were isolated from clinical specimens contained in the RMTase genes and showed resistance to amikacin, tobramycin, and gentamicin. A total of 23 (60.5%) isolates carried class 1 integrons, but no isolates in our study harbored class 2 and class 3 integrons. Class 1 integrons detected in our study harbored genes encoding resistance to aminoglycosides (aadA2, aadA5, aadA7, and aacCA5), ${\beta}$-lactams ($bla_{PSE}$), erythromycin (ereA), lincosamides (linF), and trimethoprim (dfrA12, dfrA17, and dfrA32). We confirmed that the RMTase genes had spread among only the P. mirabilis isolates from clinical specimens, but class 1 integrons had widely disseminated among P. mirabilis isolates from clinical specimens and chickens. In addition, identical REP-PCR banding patterns were evidenced in only P. mirabilis isolates from chickens. Our results suggest the horizontal spreading of P. mirabilis isolates in the chicken farm. To prevent further spreading of antimicrobial resistant genes among P. mirabilis isolates, monitoring and clinical policing will be required.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.41-44
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• 2015

We reported an outbreak of clinical strangles in thoroughbred horses due to capnophilic Streptococcus equi subsp equi in South Korea. On three different farms, we isolated 17 S equi subsp equi isolates from 29 horses with or without abscesses in their lymph nodes. Of the 17 isolates, two isolates from clinical cases grew well in aerobic conditions, whereas 7/7 isolates from clinical cases and 8/22 isolates from the nasal discharges of horses did not. The latter 15 isolates were capnophilic, oxygen-sensitive, and $CO_2$-requiring S equi subsp equi, which could not grow in aerobic conditions, but which grew well in a $CO_2$ incubator with 5% $CO_2$, in anaerobic conditions using a GasPak, and with reduced oxygen tension in a candle jar. This study is the first report of a strangles outbreak caused by capnophilic S equi subsp equi in South Korea.

• Journal of Veterinary Clinics
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• v.5 no.1
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• pp.53-59
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• 1988

한국 재래산양에 대한 L. monocytogenes균의 감염원을 조사하기 위하여 총 459개의 재래산양 분변, 비즙, 장기, 사료 및 토양재료로부터 균분리를 시도하였으며, 분리균의 항균성 물질에 대한 감수성 및 인공 감염시의 L. monocytogenes의 침입장기를 조사하였던 결과는 다음과 같다. L. monocytogenes는 분변에서만 분리되었으며 (분리율 8.2%) 분변이 본균의 주요 감염원으로 인정되었다. 가검재료로부터 L. monocytogenes의 분리방법으로는 유제화 재료를 혈액배지로써 37에서 24～48시간 동안 호기배양함이 우수하였다. 분리된 L. monocytogenes 8주 중 100%의 균주가 amikacin, colistin, tanamycin, neomycin에 내성을 나타내었으며, clinmycin, gentamicin, lincomycin, methicillin 및 refampin에 87.5%, ampicillin및 oles-ndomycin에 75.0%, Chloramphenico에 62.5%, tetracycline에 50.0% 및 cephalot hin에 37.5%의 균주가 내성이었다. Nitrofurantoin에는 전 균주가 감수성을 나타내었다. L. monocytogenes를 재래산양에 경구 및 정맥내로 접종하였을때 패혈증이 인정되었으며 대부분의 실질장기가 이 균의 침입부위인 것으로 관찰되었다.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.346-350
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• 2007

We analyzed the phenotypic changes in coagulase serotype of S. aureus isolated from clinical sources and nasal cavities of healthy persons, $1994{\sim}2005$. A total of 715 isolates, 408 methicillin resistant S. aureus (MRSA) from clinical sources and 307 methicillin-susceptible S. aureus (MSSA), were classified into eight coagulase sero-types, I to VIII. The most prevalent serotype in MRSA was type II (54.3%, 222/408) and followed IV (24.7%), III (10.9%), and V (5.2%), whereas the majorities in MSSA were type VII (30.9%, 95/307), IV (22.2%), V (22.2%) and II (7.1%). Among the isolates collected periods, significant changes of coagulase serotypes in both strains were observed. In MRSA strains, the serotype V was not detected until 1997, but rapidly increased to 18.5% (20/108) in 2005, and the serotypes III decreased from 27% (31/115) in 1994 to 0.9% (1/108) in 2005. A similar trend in MSSA strains was observed but serotype II strain was not detected in 2005. The antigenic shift and changes in the coagulase of S. aureus were confirmed.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.110-117
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• 2018

In the present study, mec complex typing and SCCmec typing were performed to analyze the molecular genetic characteristics of 20 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from clinical specimens and 4 strains isolated from the ICU environments of secondary medical institutions in a Chungnam province, Korea, from June to July of 2017. Among a total of 20 MRSA strains isolated from clinical specimens, 8 cases (40%) were SCCmec type II, one case (5%) was SCCmec type IVa, and 11 cases (55%) were not-typeable in SCCmec type analysis. Among 4 MRSA isolates from the ICU environment, one strain did not have the mecA gene and 3 strains were typed as SCCmec types II, III, and IVa, respectively. Data from the present study showed that the origin of MRSA isolated from the clinical specimens was different from those from the ICU environment in most cases but the origin was concordant in one case. In this case, MRSA might be transmitted by healthcare workers to the ICU environment. Further study with a large number of cases and other hospital infection-related microorganisms will be needed. This continuous follow-up study might provide useful information on infection control in medical institutions.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.414-421
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• 2018

In this study, Gram-positive bacilli (GPB) were identified by MALDI-TOF MS and analyzed according to the quaternary and microbial strains in the blood culture medium over a two year period at a university hospital. The results were as follows. The overall positive rate of blood culture was 9.97%. In 713 isolated GPB, 410 strains (57.5%) were identified using a microflex MALDI Biotyper. The positive rate of GPB among the blood culture positive bacteria was 8.2%, and the quarterly isolation rate was 9.8% in the third quarter of 2015, 8.7% in the second quarter of 2016, 8.1% in the third quarter of 2016, 8.1% in the first quarter of 2015, 7.9% in the first quarter of 2015, 7.9% in the second quarter of 2015, 6.8% in the first quarter of 2016, and 6.7% in the fourth quarter of 2015. The isolates were Corynebacterium striatum 89 (12.4%), Bacillus cereus 60 (8.4%), Bacillus subtilis 30 (4.2%), Paenibacillus urinalis 29 (4.1%), and Listeria monocytogenes 25 (3.5%). The results of 16S rRNA sequencing of 43 isolates (86.0%) were consistent with those of the other 50 isolates. Five out of the seven unmatched weeks were not identified by MALDI-TOF MS.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.100-109
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• 2018

The emergence and dissemination of multidrug-resistant (MDR) Acinetobacter baumannii isolates have been reported worldwide, with most of these possessing the ability to form biofilms. Biofilm formation is an important virulence factor associated with the resistance to disinfection and desiccation. This study examined the genetic basis of antimicrobial resistance mechanisms of biofilm-forming A. baumannii clinical isolates. Imaging and quantification of biofilms were performed by a crystal violet assay and 46 biofilm-forming A. baumannii isolates were selected. Subsequently, 16 isolates belonging to different clones were identified using REP-PCR, and detection of the antimicrobial determinants in the isolates was carried out. The 16 isolates included 9 non-MDR and 7 MDR isolates. The mean biomass $OD_{560}$ values of the non-MDR (0.96) and MDR (1.05) isolates differed but this difference was not significant. In this study, most biofilm-forming MDR A. baumannii isolates contained various antimicrobial resistance determinants ($bla_{OXA-23}$, armA, and mutations of gyrA and parC). On the other hand, most biofilm-forming non-MDR A. baumannii isolates did not contain antimicrobial resistance determinants. These results suggest that there is little correlation between the biofilm-forming ability and antimicrobial susceptibility in A. baumannii isolates. In addition, the emergence of MDR A. baumannii clinical isolates is generally caused by mutations of the genes associated with antimicrobial resistance and/or the acquisition of various antimicrobial resistance determinants.

• Korean Journal of Microbiology
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• v.31 no.2
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• pp.105-112
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• 1993

Plesiomonas shigelloides distributed in the aquatic systems was isolated and identified in this study and compared with the c1inica] isolates in view of their physiological characteristics, Biochemica] charactristics of the isolates of P. shigelloides one sample taken from Gupo and two samples taken from Mu]gum, were studied. However, none was isolated in Haeundae, Dadaepo, Kangdong and Nakdong estuary. The isolated bacteria had an optimum growth condition in peptone water of $25~35^{\circ}C$, pH 7.5-8.0 and 1% NaCI concentration. The cell grew most properly on the selective enrichment media which were made from adding inositol to peptone water. DNase was s]owly produced and the results were different from those of other studies. The components of the fatty acid were 3% of 3-hydroxy]ated fatty acid containing $C_{12}~C_{18}$. 0-10% cyclopropane ($C_{17:0}$), 25~30% hexadecanoic acid ($C_{16:0}$), 32~43% hexadecenoic acid ($C_{16:1}$), 1~2% octadecanoic acid ($C_{16:0}$), and 9~14% octadecenoic acid ($C_{18:1}$). Bacterio]ogica] characteristics, susceptibility of antibiotics, and the components of fatty acid of the c1inica] isolates were similar to those of the strains isolated from the aquatic systems. The strains isolated from c1inica] sources degraded lactose more fast than those isolated from the aquatic systems. There existed resistant bacteria to chlorampenicol in the strains from patients, but there were no resistant bacteria in the strains from the aquatic systems. The components of fatty acid of the clinical isolates were 0~2% $C_{17:0 cyclo}$ and 2~3% $C_{18:0}$, but those of the strains from the aquatic systems were 2~10% and 1~2%, respectvely, which showed the quantitative difference between both components.

• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.248-256
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• 2005

Background : Nontuberculous mycobacterial (NTM) infections are increasingly being recognized as a cause of chronic pulmonary disease. This study describes the prevalence of NTM species from clinical specimens and the clinical characteristics of NTM pulmonary disease. Material and Methods : The NTM isolated from March 2003 to December 2003 at the Kosin Medical Center were identified using an oligonucleotide chip containing the internal transcribed space (ITS) sequence. The medical records of the patients with the NTM isolates, who fulfilled the 1997 ATS diagnostic criteria for NTM pulmonary disease, were analyzed, retrospectively. Results : Twenty four species (24.2%) of NTM were isolated from 99 cultured AFB specimens. M. avium complex (MAC) (13 isolates), M. szulgai (3), M. kansasii (2), M. malmoense (2), M. abscessus (1), M. chelonae (1), M. scrofulaceum (1), and unclassified (1). Of the 23 patients with isolated NTM, 11 patients were found to be compatible with a NTM pulmonary infection according to the ATS criteria; MAC was found in 6 cases (54.5%), M. szulgai in 2 cases (18.2%), and M. abscessus, M. szulgai, M. kansasii and M. malmoense in 1 case each (9.1%). Ten patients (91%) were male and the median age at diagnosis was 61 years. In the pre-existing diseases, malignant disease was found in 6 cases including 5 patients with lung cancer, and history of old pulmonary tuberculosis was identified in 4 cases. The radiological patterns showed lung destruction lung in 3 cases, a cavitary mass in 3 cases, a nodular pattern in 2 cases, and reticulonodular, consolidation and a bronchiectasis pattern were in 1 case each. Conclusion : Various types of NTM pulmonary diseases were found in a tertiary hospital at Busan, Korea. The NTM pulmonary diseases were caused by MAC, M. szugai, M. kansasii, M. malmoense, M. abscessus, M. chelonae, and M. scrofulaceum in the order of frequency.