Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Causing Invasive Pneumococcal Disease in Korea Between 2017 and 2019 After Introduction of the 13-Valent Pneumococcal Conjugate Vaccine

Background@#Streptococcus pneumoniae is a serious pathogen causing various infections in humans. We evaluated the serotype distribution and antimicrobial resistance of S. pneumoniae causing invasive pneumococcal disease (IPD) after introduction of pneumococcal conjugate vaccine (PCV)13 in Korea and investigated the epidemiological characteristics of multidrug-resistant (MDR) isolates. @*Methods@#S. pneumoniae isolates causing IPD were collected from 16 hospitals in Korea between 2017 and 2019. Serotyping was performed using modified sequential multiplex PCR and the Quellung reaction. Antimicrobial susceptibility tests were performed using the broth microdilution method. Multilocus sequence typing was performed on MDR isolates for epidemiological investigations. @*Results@#Among the 411 S. pneumoniae isolates analyzed, the most prevalent serotype was 3 (12.2%), followed by 10A (9.5%), 34 (7.3%), 19A (6.8%), 23A (6.3%), 22F (6.1%), 35B (5.8%), 11A (5.1%), and others (40.9%). The coverage rates of PCV7, PCV10, PCV13, and pneumococcal polysaccharide vaccine (PPSV)23 were 7.8%, 7.8%, 28.7%, and 59.4%, respectively. Resistance rates to penicillin, ceftriaxone, erythromycin, and levofloxacin were 13.1%, 9.2%, 80.3%, and 4.1%, respectively. MDR isolates accounted for 23.4% of all isolates. Serotypes 23A, 11A, 19A, and 15B accounted for the highest proportions of total isolates at 18.8%, 16.7%, 14.6%, and 8.3%, respectively. Sequence type (ST)166 (43.8%) and ST320 (12.5%) were common among MDR isolates. @*Conclusions@#Non-PCV13 serotypes are increasing among invasive S. pneumoniae strains causing IPD. Differences in antimicrobial resistance were found according to the specific serotype. Continuous monitoring of serotypes and antimicrobial resistance is necessary for the appropriate management of S. pneumoniae infections.

Performance Validation of Three Scoring Systems for the Prediction of Thrombotic Microangiopathy Due to Severe ADAMTS13 Deficiency and the Response to Therapeutic Plasma Exchange: First Study in Korea

Background@#The BENTLEY score (B-S), French thrombotic microangiopathy (TMA) Reference Center score (FTMA-S), and PLASMIC score (PLASMIC-S) have been developed for TMA diagnostic prediction. We retrospectively validated their predictive performances in patients with severe (<10%) disintegrin and metalloprotease with thrombospondin type 1 motif, member 13 (ADAMTS13) deficiency in terms of the risk of TMA and response to therapeutic plasma exchange (TPE). @*Methods@#The predictive performances of the three scoring systems were compared in 145 patients with suspected TMA who underwent ADAMTS13 activity tests between January 2014 and September 2022. The response to TPE and mortality in TMA-positive patients were compared after risk stratification, using the Mann–Whitney U and Fisher’s exact tests. @*Results@#The PLASMIC-S, FTMA-S, and B-S showed area under the curve values of 0.820, 0.636, and 0.513, respectively, for predicting TMA positivity in high-risk patients. The PLASMIC-S showed higher sensitivity (81.8%), negative predictive value (91.2%), positive predictive value (PPV; 66.7%), and accuracy (82.1%) than the FTMA-S (72.7%, 82.1%, 41.0%, and 60.0%, respectively) and B-S (4.6%, 70.2%, 50.0%, and 69.7%, respectively). The PLASMIC-S also showed higher specificity than the FTMA-S (82.2% vs. 54.5%). The modified PLASMIC-S, including lactate dehydrogenase/upper limit of normal ratios, increased the specificity, PPV, and accuracy to 97.0%, 92.3%, and 92.4%, respectively. In TMA-positive patients, high risk assessed by the PLASMIC-S predicted higher platelet recovery rates and less TPE sessions required for recovery than for those assessed at low-to-intermediate risk. @*Conclusions@#PLASMIC-S is the preferred scoring system for detecting patients with TMA positivity and for prognosis before confirmation of ADAMTS13 activity.

Differences in Clinical Characteristics of Invasive Tracheobronchial Aspergillosis according to the Presence of Invasive Pulmonary Aspergillosis / 결핵및호흡기질환

Background@#The association of invasive tracheobronchial aspergillosis (ITBA) with invasive pulmonary aspergillosis (IPA) is not well established. We aimed to compare clinical characteristics between patients who exhibited ITBA with IPA and those who exhibited isolated ITBA (iITBA). Additionally, the usefulness of serum or bronchial galactomannan (GM) tests in diagnosing ITBA was evaluated. @*Methods@#This retrospective single-center case-control study was conducted over a period of 4 years. Fifteen patients were enrolled after confirming the presence of ITBA using bronchoscopy-guided biopsy (iITBA, 7 vs. ITBA+IPA, 8). Clinical characteristics of patients and results obtained from serum or bronchial GM tests were compared between the two groups. Mortality was assessed using data collected from a 6-month follow-up period. @*Results@#The ITBA+IPA group showed a higher prevalence of hematologic malignancy (75% vs. 14%, p=0.029), a greater number of patients with multiple bronchial ulcers (75% vs. 14%, p=0.029), lower platelet counts (63,000/μL vs. 229,000/μL, p<0.001), and a mortality rate which was significantly higher (63% vs. 0%, p=0.026) than the iITBA group. In the ITBA+IPA group, 57% of patients tested positive according to the serum GM assay, whereas in the iITBA group, all patients tested negative (p=0.070). The bronchial GM level was high in both groups, but there was no significant difference between them. @*Conclusion@#Patients with ITBA+IPA had a greater number of hematologic malignancies with lower platelet counts and a poorer prognosis than patients diagnosed with iITBA. Findings obtained from bronchoscopy and bronchial GM tests were more useful in diagnosing ITBA than the serum GM test results.

Differences in Clinical Characteristics of Invasive Tracheobronchial Aspergillosis according to the Presence of Invasive Pulmonary Aspergillosis / 결핵및호흡기질환

Background@#The association of invasive tracheobronchial aspergillosis (ITBA) with invasive pulmonary aspergillosis (IPA) is not well established. We aimed to compare clinical characteristics between patients who exhibited ITBA with IPA and those who exhibited isolated ITBA (iITBA). Additionally, the usefulness of serum or bronchial galactomannan (GM) tests in diagnosing ITBA was evaluated. @*Methods@#This retrospective single-center case-control study was conducted over a period of 4 years. Fifteen patients were enrolled after confirming the presence of ITBA using bronchoscopy-guided biopsy (iITBA, 7 vs. ITBA+IPA, 8). Clinical characteristics of patients and results obtained from serum or bronchial GM tests were compared between the two groups. Mortality was assessed using data collected from a 6-month follow-up period. @*Results@#The ITBA+IPA group showed a higher prevalence of hematologic malignancy (75% vs. 14%, p=0.029), a greater number of patients with multiple bronchial ulcers (75% vs. 14%, p=0.029), lower platelet counts (63,000/μL vs. 229,000/μL, p<0.001), and a mortality rate which was significantly higher (63% vs. 0%, p=0.026) than the iITBA group. In the ITBA+IPA group, 57% of patients tested positive according to the serum GM assay, whereas in the iITBA group, all patients tested negative (p=0.070). The bronchial GM level was high in both groups, but there was no significant difference between them. @*Conclusion@#Patients with ITBA+IPA had a greater number of hematologic malignancies with lower platelet counts and a poorer prognosis than patients diagnosed with iITBA. Findings obtained from bronchoscopy and bronchial GM tests were more useful in diagnosing ITBA than the serum GM test results.

Serotype Distribution and Antimicrobial Resistance of Invasive and Noninvasive Streptococcus pneumoniae Isolates in Korea between 2014 and 2016

BACKGROUND: Several factors contribute to differences in Streptococcus pneumoniae serotype distribution. We investigated the serotype distribution and antimicrobial resistance of S. pneumoniae isolated between 2014 and 2016 in Korea. METHODS: We collected a total of 1,855 S. pneumoniae isolates from 44 hospitals between May 2014 and May 2016, and analyzed the serotypes by sequential multiplex PCR. We investigated the distribution of each serotype by patient age, source of the clinical specimen, and antimicrobial resistance pattern. RESULTS: The most common serotypes were 11A (10.1%), followed by 19A (8.8%), 3 (8.5%), 34 (8.1%), 23A (7.3%), and 35B (6.2%). The major invasive serotypes were 3 (12.6%), 19A (7.8%), 34 (7.8%), 10A (6.8%), and 11A (6.8%). Serotypes 10A, 15B, 19A, and 12F were more common in patients ≤5 years old, while serotype 3 was more common in patients ≥65 years old compared with the other age groups. The coverage rates of pneumococcal conjugate vaccine (PCV)7, PCV10, PCV13, and pneumococcal polysaccharide vaccine 23 were 11.8%, 12.12%, 33.3%, and 53.6%, respectively. Of the 1,855 isolates, 857 (46.2%) were multi-drug resistant (MDR), with serotypes 11A and 19A predominant among the MDR strains. The resistance rates against penicillin, cefotaxime, and levofloxacin were 22.8%, 12.5%, and 9.4%, respectively. CONCLUSIONS: There were significant changes in the major S. pneumoniae serotypes in the community. Non-PCV13 serotypes increased in patients ≤5 years old following the introduction of national immunization programs with the 10- and 13-polyvalent vaccines.

Bone marrow metastasis of small cell lung carcinoma with spontaneous tumor lysis syndrome without hepatic metastasis at diagnosis: first case report in Korea and review of literature

No abstract available.

High-grade nodal marginal zone lymphoma with diffuse bone marrow involvement and IgM-type monoclonal paraproteinemia: a case report and review of the literature

No abstract available.

Development and Evaluation of Multiplex PCR for the Detection of Carbapenemase-Producing Enterobacteriaceae / 대한임상미생물학회지

BACKGROUND: The isolation of carbapenemase-producing Enterobacteriaceae (CPE) has become increasingly common. Continuous surveillance for these organisms is essential because their infections are closely related to outbreaks of illness and are associated with high mortality rates. The aim of this study was to develop and evaluate multiplex PCR as a means of detecting several important CPE genes simultaneously. METHODS: We aimed to develop a multiplex PCR that could detect seven CPE genes simultaneously. The multiplex PCR was composed of seven primer sets for the detection of KPC, IMP, VIM, NDM-1, GES, OXA-23, and OXA-48. We designed different PCR product sizes of at least 100 bp. We evaluated the performance of this new test using 69 CPE-positive clinical isolates. Also, we confirmed the specificity to rule out false-positive reactions by using 71 carbapenem-susceptible clinical strains. RESULTS: A total of 69 CPE clinical isolates showed positive results and were correctly identified as KPC (N=14), IMP (N=13), OXA-23 (N=12), OXA-48 (N=11), VIM (N=9), GES (N=5), and NDM (N=5) by the multiplex PCR. All 71 carbapenem-susceptible clinical isolates, including Enterococcus faecalis , Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, showed negative results. CONCLUSION: This multiplex PCR can detect seven CPE genes at a time and will be useful in clinical laboratories.

Corrigendum: Elucidation of Bacterial Pneumonia-Causing Pathogens in Patients with Respiratory Viral Infection / 결핵및호흡기질환

In this article, the ethical statement was missing.

Low-grade follicular lymphoma involvement of the bone marrow with a mixed paratrabecular, diffuse, and massive pattern expressing typical mantle cell lymphoma immunophenotype CD23−/FMC7+: a case report

No abstract available.

Elucidation of Bacterial Pneumonia-Causing Pathogens in Patients with Respiratory Viral Infection / 결핵및호흡기질환

BACKGROUND: Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. METHODS: Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. RESULTS: A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ≥16 years, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. CONCLUSION: The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia.

Maternal Stress and Depressive Symptoms and Infant Development at Six Months: the Mothers and Children's Environmental Health (MOCEH) Prospective Study

Our objective is to evaluate the relationships between prenatal maternal stress and depressive symptoms, respectively, and infant neurodevelopment at 6 months, adjusted for heavy metals and oxidative stress. This research is a part of a multi-center birth cohort study in South Korea. Information on stress and depressive symptoms was collected during the first trimester using Psychosocial Well-Being Index Short Form (PWI-SF) and Center for Epidemiological Studies Depression Scale (CES-D). The Korean Bayley Scales of Infant Development-II assessment (BSID-II), which includes the standardized mental development index (MDI) and psychomotor developmental index (PDI), and Korean Ages & Stages Questionnaires (K-ASQ) were applied to infants at six months of age. A higher index score indicates better development. Among 641 babies, 320 were female (50%). Maternal PWI ≥ 29 (vs. PWI ≤ 18) during early pregnancy was associated with a decrease in MDI scores of 5.37 points (P = 0.02) after adjusting for socioeconomic factors. Maternal CES-D ≥ 26 (vs. CES-D ≤ 10) during early pregnancy was associated with a decrease in MDI scores of 8.18 points (P = 0.01). The associations remained significant even after adjustment for lead, cadmium, and MDA levels (P < 0.05). However, no association was found between maternal PWI/CES-D and PDI score. No interaction was observed between stress and lead exposure. We found an inverse association between prenatal maternal stress and depressive symptoms, and MDI scores in 6-month-old infants after adjustment for prenatal lead exposure, which is known to affect cognitive function negatively.

The Combination of Real-Time PCR and HPLC for the Identification of Non-Tuberculous Mycobacteria

We used HPLC and AdvanSure real-time PCR (LG Life Sciences, Korea) to retrospectively analyze non-tuberculous mycobacteria (NTM) in 133 clinical specimens. The specimens were culture-positive for NTM and the HPLC method identified 130 strains of mycobacteria from the cultures (97.7%) at the species level. Among the isolates, 48 Mycobacterium. kansasii (36.1%), 39 M. intracellulare (29.3%), 17 M. avium (12.8%), 16 M. abscessus (12.0%), 6 M. fortuitum (4.5%), 2 M. szulgai (1.5%), 2 M. gordonae (1.5%), and 3 unclassified NTM strains (2.3%) were identified. The real-time PCR assay identified 60 NTM-positive specimens (45.1%), 65 negative specimens (48.9%), and 8 M. tuberculosis (TB)-positive specimens (6.0%). The real-time PCR assay is advantageous because of its rapid identification of NTM. However, in our study, the real-time PCR assay showed relatively low sensitivity (45.1%) when using direct specimens including sputum and bronchoalveolar lavage (BAL) fluid. HPLC is useful as it discriminates NTM at the species level, although it is time-consuming and requires specific equipment and technical expertise. A combination of both methods will be helpful for the rapid and accurate identification of mycobacteria in clinical laboratories.

Nasal Colonization and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus among Hemodialysis Patients in 7 Korean Hospitals / 병원감염관리

BACKGROUND: Staphylococcus aureus is a major bacteremia-causing pathogen in hemodialysis patients, frequently colonizing patient skin and mucosa. Active infection control is necessary to prevent methicillin-resistant S. aureus (MRSA) infection in hospitals; however, the spread of community-associated MRSA has recently become a concern for MRSA infection control. We evaluated the nasal colonization of MRSA among hemodialysis patients and the molecular characterization of the MRSA isolates. METHODS: Nasal swabs were obtained from 482 hemodialysis patients in 7 nationwide hospitals in November 2009, and cultured for MRSA colonization. Swabs were inoculated and cultured in 6.5% NaCl tryptic soy broth, then subcultured on MRSASelect medium (Bio-Rad, Hercules, CA) for 20-24 h. Multiplex PCR was performed to analyze staphylococcal cassette chromosome mec (SCCmec) types of MRSA isolates. RESULTS: Of 482 hemodialysis patients, 57 (11.8%) carried MRSA, ranging from 6.7% to 19.0%. Among the 57 MRSA isolates, we identified 3 (5.3%) SCCmec II, 1 (1.8%) SCCmec IIA, 30 (52.6%) SCCmec IIB, 1 (1.8%) SCCmec III, 6 (10.5%) SCCmec IV, and 16 (28.1%) SCCmec IVA subtypes. CONCLUSION: The MRSA carriage rate (11.8%) of hemodialysis patients in this study was high. The SCCmec IIB subtype, a healthcare-associated strain, was the predominant strain, although SCCmec IV isolates, typically found in community-associated MRSA infections, were also frequently observed. To prevent healthcare-associated MRSA infections in hemodialysis patients, standardized infection control measures should be performed, and efforts to reduce MRSA carriage rates should be considered.

Association between Prenatal Exposure to Cadmium and Atopic Dermatitis in Infancy

Our objective was to evaluate the relationship between intrauterine exposure to cadmium and the presence of atopic dermatitis in infants 6 months of age, adjusted for covariates including exposure to other heavy metals. The present research is a component of the Mothers' and Children's Environmental Health (MOCEH) study, a multi-center birth cohort project conducted in Korea. Study subjects were restricted to pregnant women in whom cadmium and lead levels were measured at delivery and whose infants were assessed for the presence of atopic disease at 6 months of age. The odds ratio (OR) for the presence of atopic dermatitis in 6-month-old infants whose cord blood had elevated cadmium levels, after adjustment for other covariates, was 2.350 (95% CI, 1.126-4.906). The OR for the presence of atopic dermatitis in infants whose cord blood had elevated lead levels was not significant. In the present study, the cord blood cadmium level was significantly associated with the presence of atopic dermatitis in 6-month-old infants; this was not true of the cord blood lead level. To the best of our knowledge, this is the first prospective study to show a relationship between prenatal exposure to cadmium and atopic dermatitis in infancy.

Performance Evaluation of Immunoassay Detection of HBsAg Mutants and Their Clinical Significance in the High Risk Groups

BACKGROUND: False negative results have been reported in the immunodetection of hepatitis B virus (HBV) because of the existence of the various mutants of the virus, causing most suppliers to try to develop superior reagents by using highly sensitive and specific monoclonal or polyclonal antibodies. In this study, we evaluated the effectiveness of 3 newly developed reagents by major manufacturers by adopting automated methods with increased sensitivity and specificity in the detection and discrimination of native and recombinant mutant antigens. METHODS: We analyzed samples confirmed positive for hepatitis B surface antigen (HBsAg), high-risk samples from chronic hepatitis patients treated with antiviral agents, and samples from patients who had undergone liver transplantation and were treated with high-dose hepatitis B immunoglobulin (HBIG) by using reagents and systems newly developed by Abbott Laboratories (USA), Roche Diagnostics (Germany), and Siemens Healthcare Diagnostics (USA). Recombinant sample panels from these manufacturers with low and high concentrations were also analyzed for comparing the 3 reagents. RESULTS: There were no discrepant results among the various selected patient groups; however, for the recombinant mutant panels, all of the 3 reagents showed highly positive detection rates for their corresponding mutant panels, but showed relatively discrepant mutant detection rates when cross-tested with the other mutant panels. Detection rates of the HBsAg mutant panels were higher at a higher concentration of the mutant samples, but were lower for the same mutant receptor sites at a lower concentration. CONCLUSIONS: The 3 major detection methods seem to recognize the major native mutants commonly encountered in clinical practice. However, in the case of recombinant mutants, we believe that our data are not to be interpreted as a reference standard for any reagent, because the results can only be validated for the reagents' corresponding mutant panels; such results tend to be mutually exclusive, and the enough concentration of mutants was required to be adjusted for a comparative analysis.

Bacteriology, Antibiotic Susceptibility and Empirical Antibiotics of Community-acquired Perforated Appendicitis / 감염과화학요법

BACKGROUND: The aim of this study was to study bacteriology and antibiotic susceptibility in patients with community-acquired perforated appendicitis over a five-year-period. MATERIALS AND METHODS: We conducted a retrospective review of the records of adult patients (age > or =18 years) who were diagnosed as having perforated appendicitis at Ulsan University Hospital between January 2007 and December 2011. Patients who had healthcare-associated or hospital-acquired appendicitis were excluded. Intraoperative specimens submitted to the microbiology laboratory were obtained either by aspiration of pus into a syringe or by use of a swab. Anaerobic bacterial cultures were not performed. RESULTS: Among 216 adult patients with perforated appendicitis, we analyzed 163 culture-positive cases. The overall mortality rate of patients was 0.6% (1/163). Escherichia coli was the most common pathogen (93/163, 57.0%), followed by Streptococcus spp. (45/163, 27.6%), Pseudomonas aeroginosa (13/163, 7.9%), and Enterococcus spp. (17/163, 10.4%). The susceptibility of E. coli to quinolones (ciprofloxacin or levofloxacin) was 74.1%. The susceptibility of E. coli to amoxicillin/clavulanate, cefoxitin, ceftriaxone, piperacillin/tazobactam, and carbapenem reached 75%, 86%, 90%, 98%, and 100%, respectively. Isolated E. coli, including ESBL producing organism and P. aeroginosa, were highly susceptible to piperacillin/tazobactam. Empirical antibiotics used most commonly were a combination of third generation cephalosporin and metronidazole. CONCLUSION: E. coli was the most common pathogen of community-acquired perforated appendicitis, and resistance to quinolone was greater than 25%. We cannot recommend quinolones for use as empirical therapy for treatment of perforated appendicitis.

Lung Infection Caused by Mycobacterium riyadhense Confused with Mycobacterium tuberculosis: The First Case in Korea

A slowly growing, non-chromogenic mycobacterial strain was isolated from sputum and bronchial lavage fluid samples of a patient presenting with productive cough, blood-tinged sputum, low-grade fever, and weakness. A positive acid-fast bacilli sputum smear result prompted the initiation of an anti-tuberculosis regimen. Multiplex real-time PCR showed a negative result for Mycobacterium tuberculosis complex and a positive result for nontuberculous mycobacteria. The DNA chip test confirmed this organism as a member of the genus Mycobacterium, but could not specify the species. Interestingly, the mycolic acid patterns obtained by HPLC nearly overlapped with those of M. simulans. The sequences of the Mycobacterium 16S rRNA gene and 16S-23S internal transcribed spacer region were unique and were found to have 100% similarity with those of M. riyadhense. After a review of the literature, we report this case as the first Korean case of M. riyadhense lung infection.

Multicenter Study of Molecular Epidemiology and Antibiotic Resistance of Group A Streptococci in 2008-2009 in Korea / 대한임상미생물학회지

BACKGROUND: Group A Streptococcus (GAS) is responsible for a wide spectrum of human diseases. We investigated the distribution of emm types and antibiotic resistance rates of GAS from clinical specimens in several Korean medical centers. METHODS: A total of 192 strains of GAS from throat, blood, and other specimens collected in Seoul, Busan, Ulsan, Iksan, and Jeju were studied in 2008-2009. The emm genotypes were identified using PCR and sequencing. Antimicrobial susceptibility testing was performed by disk diffusion method. Phenotypes of macrolide resistance were evaluated, and macrolide resistance genes were determined by PCR. RESULTS: The emm89 (33.9%) was most frequently detected, followed by emm1 (12.5%), emm12 (8.3%), emm4 (7.8%), and emm75 (7.3%). The distribution of emm types did not show a close relation to the type of specimen and was different for each area. The resistance rates to erythromycin (ERY) and clindamycin (CLI) were 4.6% and 3.7%, respectively. Among the nine ERY-resistant strains, the rate of constitutive resistance was 88.9%, compared with 11.1% for the M phenotype. Five of the ERY-resistant strains were emm28. CONCLUSION: This multicenter study reveals heterogenous emm genotypes by geographic area. Rates of resistance to ERY and CLI were low, and most of the ERY-resistant strains showed a constitutive macrolide-lincosamide-streptogramin B (cMLSB) phenotype.

IS6110-Restriction Fragment Length Polymorphism and Spoligotyping Analysis of Mycobacterium tuberculosis Clinical Isolates for Investigating Epidemiologic Distribution in Korea

The Beijing family of Mycobacterium tuberculosis has been emerging in the world. However, there are few nationwide data of genotypic distribution in Korea. This study aimed to identify the genotypic diversity of clinical isolates of M. tuberculosis and to demonstrate the population of Beijing family in Korea. We collected 96 clinical M. tuberculosis isolates from 11 university hospitals nationwide in Korea from 2008 to 2009. We observed 24 clusters in IS6110-RFLP analysis and 19 patterns in spoligotyping. Seventy-five isolates were confirmed to be Beijing family. Two isolates of the K strain and 12 isolates of the K family strain were also found. We found that drug resistance phenotypes were more strongly associated with Beijing family than non-Beijing family (P=0.003). This study gives an overview of the distribution of genotypes of M. tuberculosis in Korea. These findings indicate that we have to pay more attention to control of M. tuberculosis strains associated with the Beijing family.