Yonsei University · Medicine
Professor Young Uh's research lab specializes in clinical microbiology and antimicrobial resistance, with a focus on the molecular epidemiology and antibiotic resistance mechanisms of Gram-positive bacteria, particularly *Streptococcus agalactiae* (group B streptococcus), *Aerococcus viridans*, and other viridans group streptococci. The lab investigates serotype distribution, resistance gene detection (such as *ermB*, *mefA*, and *ermTR*), and phenotypic resistance patterns, especially to macrolides and beta-lactams, in clinical isolates from Korean populations. Their work contributes critical insights into the emergence of multidrug-resistant pathogens in both pediatric and adult infections.
Figures are computed from collected data and may differ slightly.
Aerococcus viridans, a catalase-negative gram-positive coccus rarely causing bacteremia, was isolated from blood cultures of a 52-yr-old man under the granulocytopenic condition. The isolate showed the typical characteristics of A. viridans, i.e., tetrad arrangements in gram stain, positive pyrrolidonyl aminopeptidase (PYR) and negative leucine aminopeptidase (LAP) reactions, and no growth at 45 degrees C. The isolate was revealed to be highly resistant to penicillin, erythromycin, clindamycin,
Among 78 erythromycin-resistant group B streptococcus (GBS) isolates from Korea, ermB was detected in 58 (74.4%), mefA was detected in 14 (17.9%), and ermTR was detected in 6 (7.7%). The most prevalent serotypes of erythromycin-resistant GBS were V (detected in 34 isolates [43.6%]) and III (detected in 33 isolates [42.3%]). All serotype V erythromycin-resistant GBS harbored the ermB gene.
Penicillin non-susceptible VGS were more resistant to erythromycin, clindamycin and ceftriaxone than were penicillin-susceptible isolates. A constitutive MLS(B) phenotype associated with erm(B) was the predominant mechanism of macrolide resistance among erythromycin non-susceptible isolates from this Korean hospital.
Despite the necessity for studies of group B streptococci (GBS), due to the increase in serious adult infections, the emergence of new serotypes, and the increased resistance to macrolide antibiotics, such studies have been limited in Korea. The primary purpose of the present study was to determine the frequency trends of GBS serotypes, including serotypes VI, VII, and VIII. The final objective was to elucidate the relationship between the genotypes and serotypes of macrolide-resistant GBS isola
In 540 beta-hemolytic streptococci, the rates of resistance to tetracycline, chloramphenicol, erythromycin, and clindamycin were 80.0, 22.8, 20.2, and 19.1%, respectively. Of the erythromycin-resistant isolates, 63.3% had the constitutive macrolide-lincosamide-streptogramin B (MLS(B)) resistance phenotype, 23.9% had the M phenotype, and 12.8% had the inducible MLS(B) resistance phenotype. The constitutive MLS(B) resistance phenotype with the erm(B) gene was dominant in Korea.
Continual monitoring of antimicrobial resistance among large-colony-forming BHS is needed to provide the medical community with current data regarding the resistance mechanisms that are most common to their local or regional environments.
The prevalence of neonatal group B streptococcal infection depends mainly on the colonization rate of pregnant women by group B streptococci (GBS). Although the colonization rate of Korean women by GBS is considered lower than in other countries, recent data on the maternal colonization rate of GBS are sparse. Methods: From August 2008 to June 2009, swab specimens from the anorectus, vagina, and urethral orifice of a sample of 234 pregnant Korean women were placed in new Granada medium (NGM-H),
The positive rate of M. pneumoniae in the primary care hospital was higher than that in the tertiary care hospital. Simultaneous detection of M. pneumoniae and macrolide-resistant mutation genes in the 23S rRNA by real-time PCR is needed for rapid diagnosis and therapy of M. pneumoniae infections.
Rapid detection of drug-resistant tuberculosis (DR-TB) is crucial for timely treatment and management. The GenoType MTBDR<i>plus</i> and MTBDR<i>sl</i> (MTBDR) assays have been endorsed by the World Health Organization (WHO) for the detection of DR-TB. However, MTBDR assays cannot simultaneously detect multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Furthermore, interpretation of the MTBDR assay requires trained people, and the assay has low sample throughput, process
The aim of this study was to investigate antimicrobial susceptibilities and macrolide resistance mechanisms of beta-hemolytic viridans group streptococci (VGS) in a tertiary Korean hospital. Minimum inhibitory concentrations (MICs) of seven antimicrobials were determined for 103 beta-hemolytic VGS isolated from various specimens. The macrolide resistance mechanisms of erythromycin-resistant isolates were studied by the double disk test and polymerase chain reaction (PCR). The overall resistance
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