Young Kyung Yoon

Predictors of persistent methicillin-resistant Staphylococcus aureus bacteraemia in patients treated with vancomycin

OBJECTIVES The high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) coupled with an increase in vancomycin use have induced vancomycin tolerance in MRSA, adversely affecting the outcome of MRSA bacteraemia. This study aimed to identify predictors of persistent MRSA bacteraemia (PMRSAB) in patients treated with vancomycin. METHODS A retrospective, case-control study was performed at a university hospital in Korea from January 2006 to February 2009. Subjects included 96 patients who had MRSA bacteraemia and received vancomycin under therapeutic drug monitoring. We compared the clinical characteristics, management and outcomes of cases with PMRSAB (>or=7 days, n = 31) with controls with non-PMRSAB (<or=3 days, n = 32). Vancomycin MICs were determined by the Vitek 2 system. RESULTS Of 96 patients with MRSA bacteraemia, MRSA isolates from 21 patients (21.9%) showed a vancomycin MIC of 2 mg/L. Independent predictors of PMRSAB were: retention of implicated medical devices [odds ratio (OR), 10.35; 95% confidence interval (CI), 1.03-104.55]; MRSA infection of at least two sites (OR, 10.24; 95% CI, 1.72-61.01); and vancomycin MIC of 2 mg/L (OR, 6.34; 95% CI, 1.21-33.09). The frequency of side effects and mean trough serum vancomycin concentrations were not significantly different between the two groups. Sixteen patients with PMRSAB subsequently received teicoplanin +/- arbekacin, linezolid or quinupristin/dalfopristin, due to vancomycin failure or intolerance. CONCLUSIONS To minimize the risk of PMRSAB, early removal of implicated devices and evaluation for metastatic infections should be encouraged. Alternative antibiotic therapy is warranted for infections due to isolates with elevated vancomycin MICs, as well as for the high rates of side effects.

Red blood cell transfusions are associated with lower mortality in patients with severe sepsis and septic shock: a propensity-matched analysis*.

Objectives:To evaluate the effects of transfusions in patients with severe sepsis and septic shock on mortality. Design:Propensity-matched analysis of a prospective observational database (April 2005 to February 2009). Setting:Twenty-two medical and surgical intensive care units in 12 teaching hospitals in Korea. Patients:One thousand fifty-four patients with community-acquired severe sepsis and septic shock. InterventionsNone. Measurements and Main Results:Of the 1,054 patients, 407 (38.6%) received a blood transfusion. The mean pretransfusion hemoglobin level was 7.7 ± 1.2 g/dL. Transfused patients had higher 28-day and in-hospital mortality rates (32.7% vs. 17.3%; p < .001, 41.3% vs. 20.3%; p < .001, respectively) and a longer duration of hospital stay (21 [interquartile range, 10–35] vs. 13 [interquartile range, 8–24] days; p < .001), but were more severely ill at admission (lower systolic blood pressure, higher Acute Physiology and Chronic Health Evaluation II score, and Sequential Organ Failure Assessment score at admission). In 152 pairs matched according to the propensity score depending on patient transfusion status, transfused patients had a lower risk of 7-day (9.2% vs. 27.0%; p < .001), 28-day (24.3% vs. 38.8%; p = .007), and in-hospital mortality rates (31.6% vs. 42.8%; p = .044). After adjusting for blood transfusion as a time-dependent variable in multivariable analysis, blood transfusion was independently associated with lower risk of 7-day (hazard ratio 0.42, 95% confidence interval 0.19–0.50, p = .026), 28-day (hazard ratio 0.43, 95% confidence interval 0.29–0.62, p < .001), and in-hospital mortality (hazard ratio 0.51, 95% confidence interval 0.39–0.69, p < .001). Conclusions:In this observational study of patients with community-acquired severe sepsis and septic shock, red blood cell transfusions were associated with lower risk of mortality.

Nosocomial Outbreak of Carbapenem-Resistant Acinetobacter baumannii in Intensive Care Units and Successful Outbreak Control Program

Acinetobacter baumannii has been increasingly reported as a significant causative organism of various nosocomial infections. Here we describe an outbreak of carbapenem-resistant A. baumannii (CRAB) in the ICUs of a Korean university hospital, along with a successful outbreak control program. From October 2007 through July 2008, CRAB was isolated from 57 ICU patients. Nineteen patients were diagnosed as being truly infected with CRAB, four of whom were presumed to have died due to CRAB infection, producing a case-fatality rate of 21.1%. In surveillance of the environment and the healthcare workers (HCWs), CRAB was isolated from 24 (17.9%) of 135 environmental samples and seven (10.9%) of 65 HCWs. The pulsed field gel electrophoresis patterns showed that the isolates from patients, HCWs, and the environment were genetically related. Control of the outbreak was achieved by enforcing contact precautions, reducing environmental contamination through massive cleaning, and use of a closed-suctioning system. By August 2008 there were no new cases of CRAB in the ICUs. This study shows that the extensive spread of CRAB can happen through HCWs and the environmental contamination, and that proper strategies including strict contact precautions, massive environmental decontamination, and a closed-suctioning system can be effective for controlling CRAB outbreaks.

Epidemiological and genetic analysis of a sustained community-wide outbreak of hepatitis A in the Republic of Korea, 2008: A hospital-based case–control study

BACKGROUND The epidemiological shift of hepatitis A has contributed to a sustained community-wide outbreak in Korea during 2008. OBJECTIVES To assess the risk factors associated with hepatitis A virus (HAV) propagation, and to analyze the circulating genotype in the sustained community-wide outbreak. STUDY DESIGN The hospital-based case-control study was conducted in an 850-bed university hospital in Seoul from April to August, 2008. For molecular analysis of HAV isolates, a 488-bp gene fragment of the VP1 region was amplified and sequenced. RESULTS In the multivariated logistic regression model, the risk factors of HAV infection adjusted by age were contacts with hepatitis A case (OR 3.98, 95% CI: 1.36-11.66), residence with child aged <or=5 years (OR 3.43, 95% CI: 1.32-8.87), consuming uncooked lettuce (OR 3.98, 95% CI: 1.83-8.68) or carrot (OR 2.38, 95% CI: 2.38-5.09), drinking tap water (OR 3.68, 95% CI: 1.62-8.37) or portable spring water (OR 2.71, 95% CI: 1.11-6.62) supplied by water purifiers, and eating out (OR 3.87, 95% CI: 1.53-9.78). All isolates analyzed belonged to genotype IIIA. There were 42 nucleotide differences in the sequenced VP1 region among the isolates. Amino acid sequences were identical with each other. CONCLUSIONS Our study suggests that sporadically contaminated food- or water-borne sources as well as person-to-person transmission might lead a sustained community-wide HAV outbreak and pre-existing dominant genotype IA might be replaced with genotype IIIA as a major epidemic strain in Korea. Our findings urge the health authority to make public guidelines for HAV vaccination and outbreak control.

Clinical impact of time to positivity for Candida species on mortality in patients with candidaemia

OBJECTIVES The time to positivity (TTP) of blood cultures is associated with the microbial load in the blood and prognosis in patients with bloodstream infections caused by various bacterial species. However, relevant information about the TTP for Candida species in candidaemia is limited. We investigated the clinical impact of the TTP on mortality in patients with candidaemia. METHODS All consecutive patients ≥ 18 years of age with candidaemia between January 2006 and July 2012 were included. The demographics, clinical and microbiological characteristics, antifungal treatment and outcomes of the patients were collected retrospectively. RESULTS A total of 152 patients were identified. The overall mortality rate at 6 weeks was 53%. The median TTP for Candida isolates was 27 h (IQR 19-37 h). A TTP of ≤ 24 h was significantly related to a higher mortality rate (P = 0.021). In a multivariate Cox regression analysis, the Charlson comorbidity index value [adjusted hazard ratio (HR) 1.15, 95% CI 1.02-1.29, P = 0.018], sequential organ failure assessment score (adjusted HR 1.23, 95% CI 1.13-1.34, P < 0.001), TTP ≤ 24 h (adjusted HR 2.74, 95% CI 1.51-4.97, P = 0.001), timing of appropriate antifungal therapy >72 h (adjusted HR 2.38, 95% CI 1.26-4.51, P = 0.008) and persistent candidaemia (adjusted HR 2.50, 95% CI 1.33-4.72, P = 0.005) were independently associated with the 6 week mortality rate. CONCLUSIONS A short TTP (≤ 24 h) for Candida species was independently associated with increased mortality in patients with candidaemia. Additional studies on the relevance of the TTP to clinical outcome in patients with candidaemia are needed.

Necrotizing fasciitis involving the chest and abdominal wall caused by Raoultella planticola

BackgroundRaoultella planticola was originally considered to be a member of environmental Klebsiella. The clinical significance of R. planticola is still not well known.Case presentationWe describe the first case of necrotizing fasciitis involving the chest and abdominal wall caused by R. planticola. The identity of the organism was confirmed using 16S rRNA sequencing. The patient was successfully treated with the appropriate antibiotics combined with operative drainage and debridement.ConclusionsR. planticola had been described as environmental species, but should be suspected in extensive necrotizing fasciitis after minor trauma in mild to moderate immunocompromised patients.

Risk factors for prolonged carriage of vancomycin-resistant Enterococcus faecium among patients in intensive care units: a case–control study

OBJECTIVES The aim of this study was to identify the risk factors for prolonged carriage of vancomycin-resistant Enterococcus faecium (VREF) in intensive care units (ICUs). METHODS A retrospective case-control study was performed in the ICUs of a university hospital in Korea from September 2006 to July 2009. VREF carriage was identified through weekly active surveillance rectal cultures. Clinical characteristics and the risk factors for VREF acquisition were compared between cases with prolonged VREF carriage (≥ 5 weeks, n = 58) and controls with shorter VREF carriage (<3 weeks, n = 36) in a multivariate logistic regression model. The effect of vancomycin consumption on vancomycin-resistant enterococci (VRE) colonization pressure was investigated using time-series analysis with an autoregressive error model. RESULTS Out of a total of 6327 rectal swab cultures examined, 1915 (30.3%) specimens from 266 patients were positive for VREF. The weekly VRE colonization pressure ranged from 0.77% to 42.42%. Vancomycin use after VREF acquisition significantly increased VREF carriage (adjusted odds ratio = 4.09; 95% confidence interval = 1.32-12.65). The case group had higher in-hospital mortality than the control group [21 (36.2%) versus 4 (11.1%), P = 0.007]. Increment of VRE colonization pressure was significantly associated with vancomycin consumption of 1week before (i.e. time t - 1) (P = 0.0028) and moderately associated with that of the corresponding week (i.e. time t) (P = 0.0595). CONCLUSIONS Vancomycin use in patients with VREF colonization might prolong the duration of carriage. Restriction of vancomycin use should be strengthened in these patients through infection control measures.

Trends of Antibiotic Consumption in Korea According to National Reimbursement Data (2008-2012): A Population-Based Epidemiologic Study.

AbstractThis study determined the trends in the quantities and patterns of nationwide antibiotic consumption in the Republic of Korea (ROK).This nationwide descriptive epidemiological study was conducted in the ROK between 2008 and 2012. The quantities and patterns of total systemic antibiotic prescriptions were analyzed using National Health Insurance claims data collected through the Health Insurance Review and Assessment service. Data concerning systemic antibiotics were collected using measurement units of the defined daily dose (DDD) per 1000 people per day according to the Anatomical Therapeutic Chemical classification.Over the 5-year study period, the annual consumption of systemic antibiotics ranged from 21.68 to 23.12 DDD per 1000 people per day. Outpatient antibiotic use accounted for 80.9% of total consumption. A regression model with autoregressive errors showed significant increased consumption of major antibiotic subgroups, including 3rd-generation cephalosporins, carbapenems, and glycopeptides (P < 0.001). However, the antibiotic use of 1st- (P = 0.003), 2nd- (P = 0.004), and 3rd-generation (P = 0.018) cephalosporins among patients who underwent surgery under monitoring by the antimicrobial stewardship programs for perioperative prescription was significantly lower than in those who underwent surgery without monitoring programs. In time-series analysis, total antibiotic consumption demonstrated significant seasonality (P < 0.001).The consumption of broad-spectrum antibiotics was noted to have increased in the ROK from 2008 to 2012, providing a possible explanation for the changing epidemiology of multidrug resistance. Larger prospective studies are needed to investigate the impact on public health of monitoring programs of perioperative antibiotic usage.

Multicenter Prospective Observational Study of the Comparative Efficacy and Safety of Vancomycin versus Teicoplanin in Patients with Health Care-Associated Methicillin-Resistant Staphylococcus aureus Bacteremia

ABSTRACT The purpose of this study was to compare the clinical efficacy and safety of vancomycin to those of teicoplanin for the treatment of adult patients with health care-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) bacteremia. A multicenter observational study was prospectively conducted in 15 teaching hospitals in Korea between February 2010 and July 2011. Adult patients (≥18 years old) with HA-MRSA bacteremia who were initially treated with vancomycin (VAN) (n = 134) or teicoplanin (TEC) (n = 56) were enrolled. Clinical and microbiological responses and drug-related adverse events were compared between the two treatment groups using univariate and multivariate logistic regression analyses. The vancomycin and teicoplanin MICs were determined by Etest. The MRSA-related mortality, duration of fever, and duration of MRSA bacteremia in the treatment groups were not significantly different. There was no significant difference in the occurrence of drug-related adverse events. Among the 190 MRSA isolates, the VAN MICs ranged from 0.5 to 2 μg/ml (MIC50 and MIC90, 1.5 μg/ml), and the TEC MIC ranged from 0.5 to 8 μg/ml (MIC50, 3 μg/ml; MIC90, 6 μg/ml). In multivariate analyses, the antibiotic type (vancomycin or teicoplanin) was not associated with treatment outcomes. This study indicates that teicoplanin is an effective and safe alternative to vancomycin for the treatment of HA-MRSA bacteremia.

Risk factors for and clinical implications of mixed Candida/bacterial bloodstream infections

Mixed Candida/bacterial bloodstream infections (BSIs) have been reported to occur in more than 23% of all episodes of candidaemia. However, the clinical implications of mixed Candida/bacterial BSIs are not well known. We performed a retrospective case-control study of all consecutive patients with candidaemia over a 5-year period to determine the risk factors for and clinical outcomes of mixed Candida/bacterial BSIs (cases) compared with monomicrobial candidaemia (controls). Thirty-seven (29%) out of 126 patients with candidaemia met the criteria for cases. Coagulase-negative staphylococci were the predominant bacteria (23%) in cases. In multivariate analysis, duration of previous hospital stay ≥7 weeks (odds ratio (OR), 2.86; 95% confidence interval (CI), 1.09–7.53), prior antibiotic therapy ≥7 days (OR, 0.33; 95% CI, 0.14–0.82) and septic shock at the time of candidaemia (OR, 2.60; 95% CI, 1.14–5.93) were significantly associated with cases. Documented clearance of candidaemia within 3 days after initiation of antifungal therapy was less frequent in cases (63% vs. 84%; p = 0.035). The difference in the rate of treatment failure at 2 weeks was not significant between cases (68%) and controls (62%; p = 0.55). The crude mortality at 6 weeks and survival through 100 days did not differ between the two patient groups (p = 0.56 and p = 0.80, respectively). Mixed Candida/bacterial BSIs showed a lower clearance rate of candidaemia during the early period of antifungal therapy, although the treatment response and survival rate were similar regardless of concurrent bacteraemia. Further studies on the clinical relevance of species-specific Candida-bacterial interactions are needed.