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.

Multiplex PCR Based Epidemiological Study for the Causes of Acute Diarrheal Disease in Adults Living in Jeju Island / 대한임상미생물학회지

BACKGROUND: We attempted to determine the characteristics of diarrheal pathogens according to species, seasonal variations, and patient age using multiplex PCR for the epidemiologic study of diarrheal disease in Jeju Island. METHODS: From March 2015 to Feb 2017, stool specimens were collected from 537 diarrheal patients older than 16 years. Multiplex PCR was used to identify pathogens and found Group A Rotavirus, enteric Adenovirus, Norovirus GI/GII, Astrovirus, Salmonella spp., Shigella spp., Vibrio spp., Campylobacter spp., Clostridium difficile toxin B (CDB), Clostridium perfringens, Yersinia enterocolitica, Aeromonas spp., Escherichia coli O157:H7, and verocytotoxin-producing E. coli (VTEC). RESULTS: Pathogens were isolated from 221 of 537 samples (41.2%); 9.3% were positive only for viral pathogens; 30.2%, only for bacterial pathogens; and 1.7%, for both viral and bacterial pathogens. Bacteria were more prevalent in spring, summer, and autumn, but viral pathogens were more prevalent in winter. Overall prevalence were Campylobacter spp. (26.7%), Clostridium perfringens (23.9%); Norovirus GII (11.4%), CDB (8.2%), Aeromonas spp. (6.3%), Group A Rotavirus (5.1%), Salmonella spp. (3.9%), Astrovirus (3.9%), Norovirus GI (3.1%), Vibrio spp (2.7%), enteric Adenovirus (1.6%), Shigella spp. (1.2%), VTEC (1.2%), and Yersinia enterocolitica (0.4%). Group A Rotavirus and Norovirus GII were more prevalent in winter and early spring. Campylobacter spp., CDB, and C. perfringens were detected frequently, without seasonal variation. CONCLUSION: Bacterial pathogens are more prevalent than viruses in acute diarrhea in adults living in Jeju Island, especially in spring, summer, and autumn. Viral pathogens are prevalent in winter. Campylobacter spp., CDB, and Clostridium perfringens are the major pathogens occurring without seasonal variations. These data will be helpful in identifying diarrheal pathogens and for treatments and prevention strategies.

Seroprevalences of Mycoplasma pneumoniae IgM Antibodies among Children Living in Jeju Island, Korea

BACKGROUND: Mycoplasma pneumoniae (MP) is a major cause of community-acquired pneumonia in children. The particle agglutination (PA) assay is a clinical test routinely used to detect MP infection and to determine total MP antibody titers. Using this assay, however, it is difficult to differentiate between IgM and IgG antibodies. The aim of this study was to investigate the seroprevalence of MP IgM antibodies in children living in Jeju Island. METHODS: We investigated the seroprevalence of mycoplasma IgM antibodies in 1,693 patients in the age of 0-10 yr who were ordered for mycoplasma IgM antibody testing in Cheju Halla Hospital between April 2011 and March 2013. Results were classified according to age, sex and the month and year during which the samples were obtained. RESULTS: The overall positive rate for mycoplasma IgM antibody was 24.7% and was higher in females than in males (P=0.012). The positive rate was lowest in infants under 6 months of age, and gradually rose with increasing age until the age of 4 yr. A major increase in positive rates was observed between January-April of 2012 and minor cyclical increases were also observed at 2-4 month intervals during the study period. CONCLUSIONS: The seroprevalence of mycoplasma IgM antibodies rises gradually with age until the age of 4 yr. A major peak in MP IgM antibody-positive cases was observed in early 2012, with minor cyclical increases at every 2-4 months. These results will be helpful in the interpretation and diagnosis of MP in children living in Jeju Island.

Clinical Characteristics of Streptococcus agalactiae Bacteremia in Adults Living in Jeju Island / 대한임상미생물학회지

BACKGROUND: Streptococcus agalactiae (Group B streptococcus, GBS) is known to be the leading cause of neonatal sepsis and meningitis in the United States and Europe. In addition, GBS infection has been increasingly noted in adults, particularly in those with underlying diseases, such as diabetes mellitus, malignancy and liver disease. A few studies reported that resistances to antibiotics, such as erythromycin, clindamycin, tetracycline are increasing. We report clinical and microbiological characteristics of GBS bacteremic patients in Jeju Island. METHODS: We retrospectively analyzed medical records, such as age, sex, underlying disease, mortality, skin defects, laboratory results and antibiotic resistances of GBS in hospitalized adult patients who were diagnosed with GBS bacteremia from 2008 to 2013 in Jeju Island. RESULTS: Twenty two adult patients were diagnosed as GBS bacteremia from 2008 to 2013. The mean age of GBS bacteremic patients was 66.2 years old. Of 22 bacteremic patients, fifteen patients (68%) were older than 60. Twenty patients (91%) of bacteremic patients had underlying diseases such as diabetes mellitus, malignancy and liver disease. Ten (45%) patients had skin defects which were on the lower extremities and buttock, fifteen (68%) patients had fever at the time of admission, twenty one (95%) patients were admitted via the emergency department. Two (9%) patients died. The mean white blood cell (WBC) count, percentile of neutrophil count, and C-reactive protein (CRP) levels were 11,488/microL, 84.3 %, 13.5 mg/dL respectively. All GBS isolates from bacteremia showed sensitivities to penicillin, ampicillin, and vancomycin, and showed resistances to erythromycin (25%), clindamycin (30%), and tetracycline (55%). CONCLUSION: Bacteremia caused by GBS was prevalent in adult patients with underlying diseases. Most of the GBS bacteremic patients were emergency cases, with a high body temperature, WBC, CRP level, and neutrophil count. Half of them had skin defects, which are considered a source of GBS bacteremia.

PCR-based Investigation of Infection Patterns in Patients with Pelvic Inflammatory Diseases in Jeju

BACKGROUND: Pelvic inflammatory disease (PID) is a microbial infection caused by the upward spread of infectious organisms through the cervical os. Early diagnosis and treatment of PID are essential for the prevention of sequelae such as ectopic pregnancies, infertility, and chronic pelvic pain. Although Chlamydia trachomatis and Neisseria gonorrhoeae are well-known causal agents of PID, there have been reports on some changes in PID-associated infection. The aim of this study was to investigate the infection patterns in patients with PID in Jeju. METHODS: Endocervical samples obtained from 65 patients with PID were tested for C. trachomatis, Mycoplasma genitalium, Mycoplasma hominis, N. gonorrhoeae, Trichomonas vaginalis, and Ureaplasma urealyticum using multiplex PCR. RESULTS: The samples were positive for C. trachomatis (63%), M. hominis (34%), U. urealyticum (20%), M. genitalium (17%), N. gonorrhoeae (9%), and T. vaginalis (6%). CONCLUSIONS: This study showed that C. trachomatis infection was prevalent and the incidence of M. hominis was higher than that of U. urealyticum.

Frequency of Mycoplasma pneumoniae Antibodies in Children Living on Jeju Island / 대한임상미생물학회지

BACKGROUND: Mycoplasma pneumoniae (MP) is a major cause of community-acquired pneumonia in children. Currently, no study exists regarding the frequency of the mycoplasmal antibody on Jeju Island. The aim of the present study was to investigate the frequency of mycoplasmal antibody among children living on Jeju Island. METHODS: From March 2009 to February 2011, the frequency of mycoplasmal antibody among 1580 pediatric (1:40, 20.8% in an antibody titer >1:320, and 10.7% in an antibody titer >1:640. The positive rates of each antibody titer were lowest in children under the age of 6 months, and the positive rates increased gradually with age until 4 years, where the frequency showed a "plateau." There were minor cyclic increases of positive rate (>1:320, >1:640) every three months from August 2009 to June 2010, and there was a major increase of positive rate (>1:320, >1:640) from July 2010 to January 2011. However, there was no positive rate cyclic pattern of mycoplasmal antibody in the lower titer (>1:40) patients. CONCLUSION: The frequency of mycoplasmal antibody titer is lowest under the age of 6 months. The positive rates rise gradually with age until the age of 4 years. The present study showed minor peaks of mycoplasmal antibody titer every three months and a major peak of mycoplasmal antibody titer. The results can be helpful for the interpretation and diagnosis of MP among pediatric patients on Jeju Island.

Maintained Seroprevalence of Toxoplasmosis among the Residents of Jeju Island, Korea

Seroepidemiological status of toxoplasmosis among the residents of Jeju island was surveyed and evaluated by ELISA with crude extract of Toxoplasma gondii. The sera of 2,348 residents (male 1,157 and female 1,191) were collected and checked for the IgG antibody titers, which showed 13.2% positive rate (309 sera). The positive rates were increasing gradually according to the age from 4.3% in teenage to 20.6% in seventies. The positive rates were significantly different between the sex by 16.2% for male and 10.2% for female (P<0.05). This positive rate of toxoplasmosis in Jeju island residents is regarded relatively higher than any other regions of Korea. And the high positive rate may be maintained continuously among Jeju island residents without any clear reasons until now but due to some parts peculiar socio-cultural tradition of Jeju island. Therefore, it is necessary to study further the epidemiology of toxoplasmosis of Jeju island.