Maternal, infant, and perinatal mortality statistics and trends in Korea between 2018 and 2020

This study aimed to identify maternal, infant, and perinatal mortality using the nationalpopulation data of South Korea between 2018 and 2020, and to analyze mortality rates according tocharacteristics such as age, date of death, and cause of death in each group. This study updates themost recent study using 2009 to 2017 data.Methods: Analyses of maternal, infant, and perinatal mortality were done with data identifiedthrough the supplementary investigation system for cases of death from the Census of PopulationDynamics data provided by Statistics Korea from 2018 to 2020.Results: Between 2018 and 2020, a total of 99 maternal deaths, 2,427 infant deaths, and 2,408 perinatal deaths were identified from 901,835 live births. The maternal mortality ratio was 11.3 deathsper 100,000 live births in 2018; it decreased to 9.9 in 2019 but increased again to 11.8 in 2020. Thematernal mortality ratio increased steeply in women over the age of 40 years. An increasing trend inthe maternal mortality ratio was found for complications related to the puerperium and hypertensive disorders. Both infant and perinatal mortality continued to decrease, from 2.8 deaths per 1,000live births in 2018 to 2.5 in 2020 and from 2.8 in 2018 to 2.5 in 2020, respectively.Conclusion: Overall, the maternal, infant, and perinatal mortality statistics showed improvements.However, more attention should be paid to women over 40 years of age and specific causes of maternal deaths, which should be taken into account in Korea’s maternal and child health policies.

Development of Oligonucleotide Chip for Detection of Drug-Resistant Mycobacterium Tuberculosis / 결핵

BACKGROUND: The resurgence of tuberculosis and the widespread emergence of multidrug-resistant M. tuberculosis have emphasized the importance of rapid and accurate diagnostic procedures. Recently, the oligonucleotide chip has proven to be a useful tool in the rapid diagnosis of infectious diseases. The purpose of this study was to rapidly and accurately detect specific mutations in the rpoB, katG and rpsL genes associated with rifampin, isoniazid and streptomycin resistance in M. tuberculosis, respectively, using a single oligonucleotide chip. METHOD: For detection of drug-resistance, 7 wild-type and 13 mutant-type probes for rifampin, 2 wild-type and 3 mutant-type probes for isoniazid, and 2 wild-type and 2 mutant-type probes for streptomycin were designed and spotted onto glass slides. Fifty-five cultured samples of M. tuberculosis were amplified by PCR, and then underwent hybridization and scanning. Direct sequencing was done to verify the results from the oligonucleotide chip and to analyze the types of mutations. RESULT: Thirty-five cases out of 40 rifampin-resistant strains(~88%) had mutations in the rpoB gene. One case had a new mutation(D516F, GAC R TTC) and another known mutation together. Twenty cases out of 42 isoniazid-resistant strains(~50%) had mutations in the katG gene, while 7 cases out of 9 streptomycin-resistant strains(~78%) had mutations in the rpsL gene. From these results, the oligonucleotide chip was confirmed to be able to detect the most frequent mutations from the genes associated with rifampin, isoniazid and streptomycin resistance. The results proved that the drug-resistance detection probes were specific. When the results from the oligonucleotide chip and DNA sequencing were compared, the types of mutations were exactly matched. CONCLUSION: The diagnostic oligonucleotide chip with mutation specific probes for drug resistance is a very reliable and useful tool for the rapid and accurate diagnosis of drug resistance against rifampin, isoniazid and streptomycin in M. tuberculosis infections.

Characterization of Extended-Spectrum-beta-Lactamase Genes from Clinical Isolates of Enterobacter species / 대한임상미생물학회지

BACKGROUND: Among Enterobacter spp. isolates from clinical specimens in Korea, the incidence of resistance to expanded-spectrum cephalosporins is becoming an ever-increasing problem. This study was designed to determine the prevalence of expanded-spectrum cephalosporins-resistant Enterobacter spp. isolates from patients in a tertiary care hospital in Busan, Korea, and to characterize the mechanism of resistance. MATERIALS AND METHODS: Nonduplicated clinical isolates of Enterobacter spp. were collected during the period of 1999-2000 in Kosin Medical Center, Busan, Korea. Antimicrobial susceptibilities were tested by disk diffusion method. Cefotaxime-resistant or intermediate isolates were examined for extended-spectrum beta-lactamase (ESBL)-production by double disk synergy (DDS) test. Minimal inhibitory concentrations were determined by agar dilution method. For detection of blaTEM and blaSHV genes, polymerase chain reactions (PCRs) were performed, and the DNA sequences of blaTEM and blaSHV genes were determined by using dideoxy-chain termination method. RESULTS: From 1999 to 2000, a total of 306 Enterobacter spp. strains were isolated from patients in Kosin Medical Center. Forty one percents of Enterobacter spp. isolates were susceptible to cefotaxime. Among 90 isolates resistant or intermediate to cefotaxime, 26 isolates (29%) showed positive results in double disk synergy test. Among DDS-positive- isolates, 22 isolates contained both of blaTEM and blaSHV genes, while one isolate only contained blaTEM gene and two isolates only contained blaSHV gene. Among 64 DDS-negative isolates, 47 isolates contained blaTEM genes, and 12 isolates also contained blaSHV genes. Nucleotide sequence analysis of PCR products from 10 DDS-positive and 6 DDS-negative isolates, which contained both of blaTEM and blaSHV genes, revealed that blaTEM-1b and blaSHV-12 genes were the dominant types of beta-lactamase gene. CONCLUSION: Expanded-spectrum cephalosporins-resistant Enterobacter spp. were wide spread in Kosin Medical Center, Busan, Korea. Some of the resistant isolates acquired resistance by production of ESBLs, and blaSHV-12 gene was the most frequent ESBL gene in cefotaxime-resistant Enterobacter spp.

Detection of rpoB Gene Mutation in Rifampin-Resistant M. Tuberculosis by Oligonucleotide Chip / 결핵

BACKGROUND: Oligonucleotide chip technology has proven to be a very useful tool in the rapid diagnosis of infectious disease. Rifampin resistance is considered as a useful marker of multidrug-resistance in tuberculosis. Mutations in the rpoB gene coding β subunit of RNA polymerase represent the main mechanism of rifampin resistance. The purpose of this study was to develop a diagnosis kit using oligonucleotide chip for the rapid and accurate detection of rifampin-resistance in Mycobacterium tuberculosis. METHOD: Tle sequence specific probes for mutations in the rpoB gene were designed and spotted onto the glass slide, oligonucleotide chip. 38 clinical isolates of Mycobacterium were tested. A part of rpoB was amplified, labelled, and hybridized on the oligonucleotide chip with probes. Results were analyzed with a laser scanner. Direct sequencing was done to verify the results. RESULT: The low-density oligonucleotide chip designed to determine the specific mutations in the rpoB gene of M. tuberculosis accurately detected rifampin resistance associated with mutations in 28 clinical isolates. Mutations at codons 531, 526, and 513 were confirmed by direct sequencing analysis. CONCLUSION: Mutant detection using oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of multidrug-resistance in M. tuberculosis.