Shinwon Lee

Salvage Treatment for Persistent Methicillin-Resistant Staphylococcus aureus Bacteremia: Efficacy of Linezolid With or Without Carbapenem

BACKGROUND Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with high mortality rates, but no treatment strategy has yet been established. We performed this study to evaluate the efficacy of linezolid with or without carbapenem in salvage treatment for persistent MRSA bacteremia. METHODS All adult patients with persistent MRSA bacteremia for 7 days from January 2006 through March 2008 who were treated at Seoul National University Hospital were studied. The results of linezolid salvage therapy with or without carbapenem were compared with those of salvage therapy with vancomycin plus aminoglycosides or rifampicin. RESULTS Thirty-five patients with persistent MRSA bacteremia were studied. The early microbiological response (ie, negative results for follow-up blood culture within 72 hours) was significantly higher in the linezolid-based salvage therapy group than the comparison group (75% vs 17%; P =.006). Adding aminoglycosides or rifampicin to vancomycin was not successful in treating any of the patients, whereas linezolid-based therapy gave an 88% salvage success rate P =.001). The S. aureus-related mortality rate was lower for patients treated with a linezolid salvage regimen than for patients continually treated with a vancomycin-based regimen (13% vs 53%; P =.030). CONCLUSIONS Linezolid-based salvage therapy effectively eradicated S. aureus from the blood for patients with persistent MRSA bacteremia. The salvage success rate was higher for linezolid therapy than for vancomycin-based combination therapy.

Is Cefazolin Inferior to Nafcillin for Treatment of Methicillin-Susceptible Staphylococcus aureus Bacteremia?

ABSTRACT About 20% of methicillin-susceptible Staphylococcus aureus (MSSA) isolates have a substantial inoculum effect with cefazolin, suggesting that cefazolin treatment may be associated with clinical failure for serious MSSA infections. There are no well-matched controlled studies comparing cefazolin with nafcillin for the treatment of MSSA bacteremia. A retrospective propensity-score-matched case-control study was performed from 2004 to 2009 in a tertiary care hospital where nafcillin was unavailable from August 2004 to August 2006. The cefazolin group (n = 49) included MSSA-bacteremic patients treated with cefazolin during the period of nafcillin unavailability, while the nafcillin group (n = 84) comprised those treated with nafcillin. Treatment failure was defined as a composite outcome of a change of antibiotics due to clinical failure, relapse, and mortality. Of 133 patients, 41 patients from each group were matched by propensity scores. There were no significant differences in baseline characteristics between the matched groups. The treatment failure rates were not significantly different at 4 or 12 weeks (10% [4/41] versus 10% [4/41] at 4 weeks [P > 0.99] and 15% [6/41] versus 15% [6/41] at 12 weeks [P > 0.99]). Cefazolin treatment was interrupted less frequently than nafcillin treatment due to drug adverse events (0% versus 17%; P = 0.02). Cefazolin had clinical efficacy similar to that of nafcillin and was more tolerable than nafcillin for the treatment of MSSA bacteremia.

Should HLA-B*5701 Screening Be Performed in Every Ethnic Group before Starting Abacavir?

Human leukocyte antigen allele (HLA)-B*5701 is associated with abacavir hypersensitivity. However, the carriage rate of HLA-B*5701 has rarely been studied in Asians. In 534 Korean patients with human immunodeficiency virus infection, HLA-B*5701 status was determined by polymerase chain reaction with HLA-B*5701-specific primers. No patients had the HLA-B*5701 allele (95% confidence interval, 0%-0.7%). This explains the paucity of immunologically confirmed cases of abacavir hypersensitivity in Koreans.

Effect of Routine Sterile Gloving on Contamination Rates in Blood Culture: A Cluster Randomized Trial

BACKGROUND Blood culture contamination leads to inappropriate or unnecessary antibiotic use. However, practical guidelines are inconsistent about the routine use of sterile gloving in collection of blood for culture. OBJECTIVE To determine whether the routine use of sterile gloving before venipuncture reduces blood culture contamination rates. DESIGN Cluster randomized, assessor-blinded, crossover trial (ClinicalTrials.gov registration number: NCT00973063). SETTING Single-center trial involving medical wards and the intensive care unit. PARTICIPANTS 64 interns in charge of collection of blood for culture were randomly assigned to routine-to-optional or optional-to-routine sterile gloving groups for 1854 adult patients who needed blood cultures. INTERVENTION During routine sterile gloving, the interns wore sterile gloves every time before venipuncture, but during optional sterile gloving, sterile gloves were worn only if needed. MEASUREMENTS Isolates from single positive blood cultures were classified as likely contaminant, possible contaminant, or true pathogen. Contamination rates were compared by using generalized mixed models. RESULTS A total of 10 520 blood cultures were analyzed: 5265 from the routine sterile gloving period and 5255 from the optional sterile gloving period. When possible contaminants were included, the contamination rate was 0.6% in routine sterile gloving and 1.1% in optional sterile gloving (adjusted odds ratio, 0.57 [95% CI, 0.37 to 0.87]; P = 0.009). When only likely contaminants were included, the contamination rate was 0.5% in routine sterile gloving and 0.9% in optional sterile gloving (adjusted odds ratio, 0.51 [CI, 0.31 to 0.83]; P = 0.007). LIMITATION Blood cultures from the emergency department, surgical wards, and pediatric wards were not assessed. CONCLUSION Routine sterile gloving before venipuncture may reduce blood culture contamination.

An outbreak of Burkholderia cenocepacia associated with contaminated chlorhexidine solutions prepared in the hospital

From October to December 2007, an outbreak of Burkholderia cenocepacia occurred in a secondary care hospital. The 19 B cenocepacia isolated from the patients, the chlorhexidine solutions of each different ward, and the purified water that diluted these solutions exhibited an identical pulsed-field gel electrophoresis pattern. Inadequate preparation of chlorhexidine solutions diluted with contaminated purified water may have resulted in an outbreak of B cenocepacia. Adequate preparation of chlorhexidine solutions should be emphasized.

Discrepancy between histology and culture in filamentous fungal infections

Although the incidence of non-Aspergillus filamentous fungal infections has increased, there is little data regarding the correlation between the results of histologic analysis and those of microbiologic culture in clinical practice. We investigated the results of fungal cultures inoculated with tissue specimens that had been found to have fungal hyphae on histologic examination at a university-affiliated tertiary care hospital. Culture studies were requested for microbiologic diagnosis for 122 (31%) of 393 patients with histologic evidence of the presence of filamentous fungal infections. In 53 (43.4%) out of the 122 specimen, fungi were recovered and identified. In 9 (17%) out of the 53 cases, the histology and culture results were discordant. These data serve to remind physicians of the need for obtaining fungus cultures in these types of cases.

Clinical and Epidemiological Factors Associated with Methicillin Resistance in Community-Onset Invasive Staphylococcus aureus Infections: Prospective Multicenter Cross-Sectional Study in Korea

Successful empirical therapy of Staphylococcus aureus infections requires the ability to predict methicillin resistance. Our aim was to identify predictors of methicillin resistance in community-onset (CO) invasive S. aureus infections. Sixteen hospitals across Korea participated in this study from May to December 2012. We prospectively included cases of S. aureus infection in which S. aureus was isolated from sterile clinical specimens ≤72 hours after hospitalization. Clinical and epidemiological data were gathered and compared in methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) cases. Community-associated (CA) infections were defined as in previous studies. In total, there were 786 cases of community-onset S. aureus infection, 102 (13.0%) of which were CA-MRSA. In addition to known risk factors, exposure to 3rd generation cephalosporins in the past 6 months [odds ratio (OR), 1.922; 95% confidence interval (CI), 1.176–3.142] and close contact with chronically ill patients in the past month (OR, 2.647; 95% CI, 1.189–5.891) were independent risk factors for MRSA infection. However, no clinical predictors of CA-MRSA were identified. Methicillin resistance, CO infection, and appropriateness of empirical antibiotics were not significantly related to 30-day mortality. MRSA infection should be suspected in patients recently exposed to 3rd generation cephalosporins or chronically-ill patients. There were no reliable predictors of CA-MRSA infection, and mortality was not affected by methicillin resistance.

The burden of nosocomial staphylococcus aureus bloodstream infection in South Korea: a prospective hospital-based nationwide study

BackgroundWe estimated the nationwide burden of nosocomial S. aureus bloodstream infection (SA-BSI), a major cause of nosocomial infection, in South Korea.MethodsTo evaluate the nationwide incidence of nosocomial SA-BSI, cases of SA-BSI were prospectively collected from 22 hospitals with over 500 beds over 4?months. Data on patient-days were obtained from a national health insurance database containing the claims data for all healthcare facilities in South Korea. The additional cost of SA-BSI was estimated through a matched case?control study. The economic burden was calculated from the sum of the medical costs, the costs of caregiving and loss of productivity.ResultsThree hundred and thirty nine cases of nosocomial SA-BSI were included in the study: 254 cases of methicillin-resistant SA-BSI (MRSA-BSI) and 85 cases of methicillin-susceptible SA-BSI (MSSA-BSI). Death related to BSI occurred in 81 cases (31.9%) of MRSA-BSI and 12 cases (14.1%) of MSSA-BSI. The estimated incidence of nosocomial MRSA-BSI was 0.12/1,000 patient-days and that of nosocomial MSSA-BSI, 0.04/1,000 patient-days. The estimated annual cases of nosocomial BSI were 2,946 for MRSA and 986 for MSSA in South Korea. The additional economic burden per case of nosocomial SA-BSI was US

Voriconazole-associated severe hyponatremia

20,494 for MRSA-BSI and

Third-generation cephalosporin resistance of community-onset Escherichia coli and Klebsiella pneumoniae bacteremia in a secondary hospital

6,914 for MSSA-BSI. Total additional annual cost of nosocomial SA-BSI was