• Korean Journal of Microbiology
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• v.48 no.4
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• pp.240-245
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• 2012

Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium that causes serious infection, particularly in immunocompromised patients. Also, P. aeruginosa possessing carbapenem-resistant metallo-${\beta}$-lactamases (MBL) has been reported with increasing frequency in Korea. We therefore analyzed the level of multidrug-resistant clinical P. aeruginosa isolated from a secondary hospital in Korea in 2010. A total of 92 isolates of P. aeruginosa were collected from Sahmyook Medical Center in 2010. Susceptibility to antimicrobial agents was determined by analysis of the minimum inhibitory concentration test; the inhibitor-potentiated disk diffusion (IPD) test was performed for MBL detection. RAPD-PCR was used for genotyping to rapidly characterize P. aeruginosa strains isolated from clinical patients. The percentages of non-susceptible isolates were as follows: 40.2% to ceftazidime, 58.7% to meropenem, 56.5% to gentamicin, 46.7% to tobramycin, 62.0% to ciprofloxacin and 97.8% to chloramphenicol. The 29 multidrug-resistant strains were screened by the IPD test: of the 21 PCR-positive isolates, 19 were IPM-1 producers and 2 were VIM-2 producers. Among the 19 IMP-1-producing P. aeruginosa isolates, 16 isolates showed similar patterns, and three different banding patterns were observed. The proportion of IMP-1-producing multidrug-resistant P. aeruginosa from clinical isolates steadily increased in this secondary hospital in Korea in 2010. This study provides information about the antimicrobial-resistant patterns and genotype of multidrug-resistant P. aeruginosa isolated from clinical isolates in Korea, 2010.

• Pediatric Infection and Vaccine
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• v.24 no.3
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• pp.125-133
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• 2017

Purpose: After the introduction of Haemophilus influenzae type b (Hib) vaccine in 1995 in Korea, it was included in the national immunization program in 2013. In the post-Hib vaccine era, some studies in other countries reported that invasive Hib disease affects adults, especially the elderly and immunocompromised persons, more often than it affects children. To evaluate disease susceptibility, quantitative and qualitative analysis of anti-polyribosylribitol phosphate (PRP) antibodies were carried out in Korean adults aged 20 to 85 years. Methods: Sera were collected from 39 healthy adults (20 to 50 years of age) and from 30 elderly adults (75 to 85 years of age) who did not have immune-compromising conditions. The concentration of anti-PRP immunoglobulin G (IgG) and serum bactericidal indices (SBIs) were measured by enzyme-linked immunosorbent assay and serum bactericidal assay. Results: Geometric mean concentrations of anti-PRP IgG and geometric mean SBIs were $0.88{\mu}g/mL$ (95% confidence interval [CI], 0.17 to 3.85) and 354 (95% CI, 50 to 2,499) in young adults and $1.67{\mu}g/mL$ (95% CI, 0.53 to 5.24) and 449 (95% CI, 146 to 1,376) in elderly adults, respectively. When the threshold of seropositivity for anti-PRP IgG was applied as 0.15 or $1.0{\mu}g/mL$, which is the protective antibody level in children, seropositive rates were 87.2% or 53.8% in young adults and 100% or 60% in elderly adults. The seropositivity rates of the SBI ($SBI{\geq}4$) were 82.1% and 100% in the groups, respectively. Conclusions: Most subjects in the adult and elderly adult groups display immunity to Hib based on quantitative and qualitative antibody levels, but not all. Because high immunization and low Hib circulation rates may reduce the natural Hib immunity in the population, monitoring Hib immunity as well as disease are needed continuously.

• Tuberculosis and Respiratory Diseases
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• v.55 no.4
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• pp.370-377
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• 2003

Background : Pneumocystis carinii pneumonia (PCP) is one of the most common cause of infection in patients with HIV infection. Recently, the incidence of PCP have been increasing in immunocompromised hosts without HIV infection. We compared the clinical characteristics of PCP between HIV infected and non-infected persons. Patients and Methods : We retrospectively reviewed the charts of 25 patients diagnosed as PCP from 1996 to 2002. Age, sex, underlying conditions, use of immunosuppressants, clinical courses, laboratory findings, treatment and prognosis were compared between HIV infected and non-infected persons. Results : Twenty-five patients with PCP were identified. 16 were HIV infected, and 9 were HIV non-infected. The mean age of overall patients was $43.4{\pm}13.2$ years. Underlying conditions in HIV non-infected persons were hematologic malignancy (7 cases), solid organ transplant (1 case), and autoimmune disease (1 case). Seven cases (77.8%) of HIV non-infected persons had a history of steroid use. Mean duration of symptoms was longer in HIV infected persons than in HIV non-infected persons, but it was not statistically significant. PaO2 was lower in HIV infected persons ($61.2{\pm}16.9$ mmHg vs. $65.4{\pm}15.4$), but it was not statistically significant. Chest X ray showed typical ground glass opacity in 12 cases (75%) of HIV infected persons and in 4 cases (44.4%) of HIV non-infected persons. Twelve cases (75%) of HIV infected persons were treated with steroid, as were 6 cases (66.7%) of HIV non-infected persons. Ventilator care was needed in 6 cases (37.5%) of HIV infected persons and in 2 cases (22.2%) of HIV non-infected persons. Mortality of HIV infected persons was 50%, and that of HIV non-infected persons was 11.1%. Conclusions : PCP showed some different clinical characteristics between HIV infected and non-infected persons. Prospective studies regarding the risk factors of PCP, prophylaxis, treatment and prognosis in HIV infected and non-infected persons are warranted.

• Pediatric Infection and Vaccine
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• v.30 no.1
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• pp.20-32
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• 2023

Purpose: This study aimed to identify the etiology and risk factors of community-acquired pneumonia (CAP) requiring hospitalization in Korean children during the coronavirus disease 2019 (COVID-19) pandemic. Methods: Clinical information of children admitted with CAP to Seoul National University Children's Hospital (SNUCH) between January 1, 2021, and February 28, 2022, was retrospectively collected and analyzed. In addition, the etiologic diagnosis and demographic data of children with CAP who were discharged at the other seven hospitals between January and February 2022 were collected. Pneumonia was diagnosed using strict criteria comprising clinical symptoms, physical examination findings, and chest radiographic findings. Results: Among 91 children hospitalized with CAP at SNUCH during the 14-month period, 68.4% were aged <5 years and 79.1% had underlying diseases. Among the 95 CAP cases, respiratory assistance was required in 70.5%, and the use of a ventilator was required in 20.0%. A total of five patients expired, all of whom were either immunocompromised or had underlying neurological diseases. Neurological diseases and immunosuppression were significantly correlated with respiratory assistance (P=0.003) and death (P=0.014). A total of 55% of the detected respiratory pathogens were viruses, the most common of which was rhinovirus at 35.9%. Among the 169 children hospitalized for CAP at the eight institutions, ≥1 respiratory virus was detected in 92.3%, among which respiratory syncytial virus (79.8%) was the most prevalent. Conclusions: Even during the COVID-19 pandemic, Korean children were hospitalized with CAP caused by seasonal respiratory viral pathogens. Although atypical and pyogenic bacteria were not detected, continuous clinical monitoring and further prospective studies should be conducted.

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.117-124
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• 2001

Purpose : Since Mendoza(1990)'s report that long term methylprednisolone pulse therapy by Mendoza protocol (MP therapy) is a good treatment option in focal segmental glomerulosclerosis(FSGS), there have been reports of the effects of this therapy in steroid-resistant nephrotic syndrome. However, no studies have been performed on the effects of MP therapy in steroid- dependent nephrotic syndrome and secondary nephrotic syndrome. In this study, we investigated the effects of long term MP therapy in primary and secondary nephrotic syndrome in which previous treatment options were not effective. Methods : We chose 10 children who were diagnosed with steroid-dependent minimal change nephrotic syndrome(SD-MCNS), who had shown frequent relapse during the immunocompromised or cytotoxic therapy Period, and 6 children with FSGS and 5 children with secondary nephrotic syndrome children, who had shown no response during the previous therapy period. We treated these patients according to Mendoza protocol involving infusions of high doses of methylprednisolone, often in combination with oral cyclophosphamide for 82 weeks. Results : In all the 10 children with SD-MCNS, complete remission was visible on average of $18{\pm}9$ days after MP therapy was started. However, all these children relapsed during or after MP therapy. In these children, the mean relapse rate prior to MP therapy was $2.1{\pm}1.0$ relpases/year, which was reduced to $1.4{\pm}0.9$ relapses/year during MP therapy(P>0.05) and rose to $2.7{\pm}1.0$ relapse/year after MP therapy. Of the 6 children with FSGS, 4 children($67\%$) showed complete remission, of whom 3 children($50\%$) remained in the remission status during the follow up period, $1.2{\pm}0.7$ years, after the end of MP therapy. 2 children($33\%$) showed no response. All of the 5 children with secondary nephrotic syndrome showed remission and remained in the remissiom status during the follow up period, $1.7{\pm}0.6$ years The only side effect of MP therapy was transient hypertension in 10 children of ail subjects during the intravenous infusion of methylprednisolone. Conclusion : We conclude that although long term MP therapy is not effective in the treatment of SD-MCNS, it is an effective therapy against intractable FSGS and secondary nephrotic syndrome. (J Korean Soc Pediatr Nephrol 2001 ; 5 : 117-24)