Establishment of the Separate Cutoff Values of 17-alpha-hydroxyprogesterone in Neonatal Screening Program for Congenital Adrenal Hyperplasia according to Birth Weight / 임상검사와정도관리

BACKGROUND: In Korea, 17-alpha-hydroxyprogesterone (17-OHP) neonatal screening for congenital adrenal hyperplasia (CAH) has a high false positive rate. Preterm infants have higher levels of 17-OHP than term infants. We established the separate cutoff values of 17-OHP under the guideline of the Clinical and Laboratory Standard Institute C28-A3 to reduce a false positive rate. METHODS: The 17-OHP enzyme-immunoassay was used in blood spots of 22,601 newborns. To decide whether to partition cutoff values based on sex, sampling date and birth weight was assessed by Z-test and standard deviation (SD) ratio. If the result was significant, we estimated the cutoff value with 90% confidence intervals (CIs) using the nonparametric method. RESULTS: In the subclasses based on sex and sampling date, the results were not significant. However, the birth weight-adjusted subclasses (SD ratio > 1.5) showed that it was necessary to distinguish low-birth-weight infants from the others. We selected the subclass categories to reflect the concept of low- or very-low-birth-weight infant. The maximum percentile to define a 90% CI was chosen in each subclass. After applied the re-estimated cutoff value, the recall rate was decreased from 0.6% to less than 0.2%. CONCLUSIONS: The birth weight-adjusted cutoff value of 17-OHP in neonatal screening for CAH can be reduced the false positive rate of low-birth-weight infants. This approach would decrease unnecessary blood draws, medical evaluation, parental anxiety and burden on health care resources.

Changing Molecular Epidemiology of Group B Streptococcus in Korea

The prevalence of group B streptococcus (GBS) among pregnant women and disease burdens in neonates and adults are increasing in Korea. Colonizing isolates, collected by screening pregnant women (n=196), and clinical isolates collected from clinical patients throughout Korea (n=234), were serotyped and screened for antibiotic resistance. Serotype III (29.8%) and V (27.7%) predominated, followed by Ia (17.0%). Antibiotic resistance was higher among clinical than colonizing isolates for erythromycin (35.1% and 26.9%; P=0.10) and for clindamycin (49.4% and 42.1%; P=0.17). erm(B) occurred in 91.9% of erythromycin resistant isolates, and 84.0% of isolates resistant to clindamycin. Only five isolates (4.2%) resistant to erythromycin were susceptible to clindamycin; by contrast, and unique to Korea, 34% of isolates resistant to clindamycin were erythromycin susceptible. Among these 60 erythromycin-susceptible & clindamycin-resistant isolates, 88% was serotype III, and lnu(B) was found in 89% of strains. Four fifths of the serotype V isolates were resistant to both erythromycin and clindamycin. Further characterization of the genetic assembly of these resistance conferring genes, erm(B) and lnu(B), will be useful to establish the clonal lineages of multiple resistance genes carrying strains.

The Recent Status of Multidrug- and Extensively Drug-Resistant Tuberculosis in Korea / 결핵및호흡기질환

BACKGROUND: The increasing incidence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) has become a serious worldwide problem. However, there is insufficient data regarding the current status of MDR-TB and XDR-TB in Korea. This study examined the recent status of MDR- and XDR-TB using the data from 7 laboratories, in which almost all drug susceptibility tests (DST) for Mycobacterium tuberculosis were performed. METHODS: The patients' identification data and DST results were collected from all 7 laboratories from 2001 to 2006 and the number of patients with MDR-TB and XDR-TB were calculated. RESULTS: The number of DSTs was 140,638 for 6 years with an increasing incidence each year (p<0.001). The number of DST with MDR results was 18,510 and personal identifying information was obtained in 16,640 (89.9%) tests. The number of MDR-TB patients from 2001 to 2006 was 2,329, 2,496, 2,374, 2,300, 2,354, and 2,178, respectively, when counting the duplications in a year as one patient. The number of MDR-TB patients when counting the duplications in 6 years as one patient was 2,281, 1,977, 1,620, 1,446, 1,512, and 1,373, respectively. When the same method was adopted, the number of XDR-TB patients was 191, 238, 282, 260, 272, and 264, respectively, and 189, 150, 130, 90, 122, and 110 patients, respectively. CONCLUSION: Despite the national efforts to control TB, there are still a large number of MDR- and XDR-TB patients in Korea.