Tae Hyong Kim

Populations at risk for severe or complicated influenza illness: systematic review and meta-analysis.

Objective To evaluate risk factors for severe outcomes in patients with seasonal and pandemic influenza. Design Systematic review. Study selection Observational studies reporting on risk factor-outcome combinations of interest in participants with influenza. Outcomes included death, ventilator support, admission to hospital, admission to an intensive care unit, pneumonia, and composite outcomes. Data sources Medline, Embase, CINAHL, Global Health, and the Cochrane Central Register of Controlled Trials to March 2011. Risk of bias assessment Newcastle-Ottawa scale to assess the risk of bias. GRADE framework to evaluate the quality of evidence. Results 63 537 articles were identified of which 234 with a total of 610 782 participants met the inclusion criteria. The evidence supporting risk factors for severe outcomes of influenza ranged from being limited to absent. This was particularly relevant for the relative lack of data for non-2009 H1N1 pandemics and for seasonal influenza studies. Limitations in the published literature included lack of power and lack of adjustment for confounders was widespread: adjusted risk estimates were provided for only 5% of risk factor-outcome comparisons in 39 of 260 (15%) studies. The level of evidence was low for “any risk factor” (odds ratio for mortality 2.77, 95% confidence interval 1.90 to 4.05 for pandemic influenza and 2.04, 1.74 to 2.39 for seasonal influenza), obesity (2.74, 1.56 to 4.80 and 30.1, 1.74 to 2.39), cardiovascular diseases (2.92, 1.76 to 4.86 and 1.97, 1.06 to 3.67), and neuromuscular disease (2.68, 1.91 to 3.75 and 3.21, 1.84 to 5.58). The level of evidence was very low for all other risk factors. Some well accepted risk factors such as pregnancy and belonging to an ethnic minority group could not be identified as risk factors. In contrast, women who were less than four weeks post partum had a significantly increased risk of death from pandemic influenza (4.43, 1.24 to 15.81). Conclusion The level of evidence to support risk factors for influenza related complications is low and some well accepted risk factors, including pregnancy and ethnicity, could not be confirmed as risks. Rigorous and adequately powered studies are needed.

Risk Factors for Acquisition of Imipenem-Resistant Acinetobacter baumannii: a Case-Control Study

ABSTRACT Risk factors for the nosocomial occurrence of imipenem-resistant Acinetobacter baumannii (IRAB) were determined. A case-control study design was used for a comparison of two groups of A. baumannii-positive patients with control patients. Nosocomial IRAB was isolated from the first group of A. baumannii-positive patients, and imipenem-susceptible A. baumannii (ISAB) was isolated from the second group. The control patients were randomly selected in a 4:1 ratio from the same medical or surgical services from which the A. baumannii-positive patients were receiving care when the isolation of IRAB occurred. Risk factors analyzed included demographic variables, comorbid conditions, variables related to hospitalization, and the antimicrobials used. IRAB was isolated from 104 patients, and ISAB was isolated from 387 patients between January and December 2000. The risk factors for IRAB were a previous intensive care unit (ICU) stay (odds ratio [OR], 21.54; 95% confidence interval [CI], 10.73 to 43.23) and prior exposure to imipenem (OR, 9.18; 95% CI, 3.99 to 21.13) or third-generation cephalosporins (OR, 2.11; 95% CI, 1.13 to 3.95). Risk factors for ISAB were a previous ICU stay (OR, 8.05; 95% CI, 5.67 to 11.44) and exposure to third-generation cephalosporins (OR, 2.07; 95% CI, 1.47 to 2.91). Our results suggest that the nosocomial occurrence of IRAB or ISAB is strongly related to an ICU stay, and IRAB occurrence may be favored by the selection pressure of imipenem.

Vaccine herd effect

Abstract Vaccination ideally protects susceptible populations at high risk for complications of the infection. However, vaccines for these subgroups do not always provide sufficient effectiveness. The herd effect or herd immunity is an attractive way to extend vaccine benefits beyond the directly targeted population. It refers to the indirect protection of unvaccinated persons, whereby an increase in the prevalence of immunity by the vaccine prevents circulation of infectious agents in susceptible populations. The herd effect has had a major impact in the eradication of smallpox, has reduced transmission of pertussis, and protects against influenza and pneumococcal disease. A high uptake of vaccines is generally needed for success. In this paper we aim to provide an update review on the herd effect, focusing on the clinical benefit, by reviewing data for specific vaccines.

Clinical Features and Outcomes of Bacteremia Caused by Enterococcus casseliflavus and Enterococcus gallinarum: Analysis of 56 Cases

The clinical significance and virulence potential of Enterococcus casseliflavus/flavescens and Enterococcus gallinarum are still uncertain. We retrospectively analyzed 56 cases of significant bacteremia caused by E. casseliflavus or E. gallinarum. Of these cases, 25 (44.6%) were associated with polymicrobial bacteremia, and 43 (76.8%) were associated with entry via the biliary tract. Resistance to vancomycin was observed in 17 (30.4%) of these 56 patients, and this resistance was significantly associated with E. gallinarum bacteremia (adjusted odds ratio [AOR], 10.56; 95% confidence interval [CI], 2.41-46.27) and bacteremia without biliary tract origin (AOR, 6.74; 95% CI, 1.44-31.67). The crude mortality rate was 13%, and the bacteremia-related mortality rate was 1.9%. In conclusion, bacteremia due to E. casseliflavus and E. gallinarum is commonly associated with biliary tract disease and may be associated with a low risk of mortality.

Incidence, Characteristics, and Outcomes of Staphylococcus lugdunensis Bacteremia

ABSTRACT Of 63 patients with Staphylococcus lugdunensis bacteremia, 15 (23.8%) had clinically significant bacteremia, with an incidence of 1.3 cases per 100,000 admissions. Of the five patients with community-acquired S. lugdunensis bacteremia, three had endocarditis. Catheters were the most common portal of entry for health-care-associated or hospital-acquired bacteremia. Only one patient died of bacteremia-related causes.

Cryptogenic pyogenic liver abscess as the herald of colon cancer

Background and Aim:  Colonic mucosal defects might be a route for bacterial invasion into the portal system, with subsequent hematogenous spread to the liver. We retrospectively investigated the results of colonoscopy and the clinical characteristics of patients with pyogenic liver abscess of colonic origin.

Early Acute Kidney Injury Is a Risk Factor That Predicts Mortality in Patients Treated with Colistin

The nephrotoxicity of colistin has been reported in the literature. A previous report has shown that acute kidney injury (AKI) occurred after an average of 13.5 days, but we have experienced that AKI developed with colistin administration earlier. We investigated clinical features of patients who developed AKI according to the time of AKI development after colistin use. We retrospectively collected the data of the patients who were admitted to 4 hospitals between January 2007 and May 2009. This study included 119 patients who had received intravenous colistin for over 72 h. We compared the early AKI group (AKI developed within 7 days) with the late AKI group. The patients’ age was 64.1 ± 14.0 years. AKI occurred in 65 of the 119 patients (54.6%). The duration of colistin use was 7.7 ± 6.4 days. AKI occurred in 46 patients within 7 days after colistin treatment and in 19 patients after 7 days. The patients with early AKI had a higher mortality rate than those with late AKI (OR: 4.37, 95% CI: 1.34, 14.18). In conclusion, clinicians might be cautioned that the mortality rate is higher for the patients with early occurrence of AKI than that for the patients with late occurrence of AKI.

Serratia Bacteremia in a Large University Hospital: Trends in Antibiotic Resistance During 10 Years and Implications for Antibiotic Use

OBJECTIVE To identify antibiotic resistance trends and risk factors for resistance of Serratia species to third-generation cephalosporins. DESIGN Retrospective survey of medical records. SETTING A 2,200-bed, tertiary-care hospital. PATIENTS One hundred twenty-two patients with Serratia bacteremia between January 1991 and June 2001. METHODS Infectious disease physicians collected data from medical records regarding patient demographics, underlying disease or condition, portal of entry, microorganism, antibiogram, complications, antibiotics received, and outcome. RESULTS Among 122 Serratia isolates, 117 (95.9%) were Serratia marcescens and 110 (90.2%) were of nosocomial origin. During the study period, the 122 isolates showed a high rate of resistance to third-generation cephalosporins (45.9%) and extended-spectrum penicillins (56.6%). The resistance rate to ciprofloxacin was 32.0%. The resistance rate to third-generation cephalosporins increased from 31.7% for 1991 to 1995 to 54.9% for 1996 to 1998 and 50.0% for 1999 to 2001. In the multivariate analysis, prior use of a second-generation cephalosporin (adjusted odds ratio [OR], 5.90; 95% confidence interval [CI90], 1.41 to 24.6; P = .015) or a third-generation cephalosporin (OR, 3.26; CI95, 1.20 to 8.87; P = .020) was a strong independent risk factor for resistance to third-generation cephalosporins. The overall case-fatality rate was 25.4% (Serratia bacteremia-related case-fatality rate, 13.1%). CONCLUSION Prior use of a second- or third-generation cephalosporin was the most important risk factor for bacteremia with Serratia resistant to third-generation cephalosporins, suggesting the need for antibiotic control. The potential role of patient-to-patient spread could not be fully evaluated in this retrospective study.

Trends in the incidence rate of device-associated infections in intensive care units after the establishment of the Korean Nosocomial Infections Surveillance System

BACKGROUND The effectiveness of continuous nationwide surveillance on healthcare-associated infections should be investigated in each country. AIM To assess the rate of device-associated infections (DAIs) in intensive care units (ICUs) since the establishment of the Korean Nosocomial Infections Surveillance System (KONIS). METHODS Nationwide data were obtained on the incidence rate of DAI in ICUs reported to KONIS by all participating hospitals. The three major DAIs were studied: ventilator-associated pneumonia (VAP), central line-associated bloodstream infection (CABSI), and catheter-associated urinary tract infection (CAUTI). The pooled and year-wise incidence rates (cases per 1000 device-days) of these DAIs were determined for the period 2006 and 2012. In addition, data from institutions that had participated in KONIS for at least three consecutive years were analysed separately. FINDINGS The number of ICUs participating in KONIS gradually increased from 76 in 2006 to 162 in 2012. Between 2006 and 2012, the incidence rate per 1000 device-days for VAP decreased significantly from 3.48 to 1.64 (F = 11, P < 0.01), for CAUTI the rate decreased non-significantly from 1.85 to 1.26 (F = 2.02, P = 0.07), and for CABSI the rate also decreased non-significantly from 3.4 to 2.57 (F = 1.73, P = 0.12). In the 132 ICUs that had participated in KONIS for at least three consecutive years, the VAP rate significantly decreased from the first year to third year (F = 20.57, P < 0.01), but the rates of CAUTI (F = 1.06, P = 0.35) and CABSI (F = 1.39, P = 0.25) did not change significantly. CONCLUSION The decreased incidence rate of VAP in ICUs in Korea might be associated with the continuous prospective surveillance provided by KONIS.

Risk Factors for Mortality in Patients with Acinetobacter baumannii Bacteremia.

Background Acinetobacter baumannii, an opportunistic nosocomial pathogen that can cause significant morbidity and mortality, has emerged as a worldwide problem. The aim of this study was to evaluate the risk factors for mortality in patients with A. baumannii bacteremia. Materials and Methods We retrospectively evaluated 118 patients who had A. baumannii bacteremia between July 2003 and December 2011. The aim of this study was to identify the 30-day mortality in patients with A. baumannii bacteremia and relevant risk factors. Results The bacteremia-related 30-day mortality rate was 34.1%. Univariate analysis revealed that the risk factors for mortality included malignancy, longer hospital stay before bacteremia, intensive care unit (ICU) stay at the time of bacteremia, mechanical ventilation, use of a central venous catheter, unknown origin of bacteremia, bacteremia due to pneumonia, antimicrobial resistance to carbapenems, and elevated Acute Physiology and Chronic Health Evaluation II and Pitt bacteremia scores. Multivariate logistic regression analysis revealed that resistance to carbapenems (odds ratio [OR]: 4.01, 95% confidence interval [CI]: 1.51 to 0.68, P = 0.005), need for mechanical ventilation (OR: 3.97, 95% CI: 1.41 to 11.13, P = 0.005), and presence of malignancy (OR: 4.40, 95% CI: 1.60 to 12.08, P = 0.004) were significantly related to mortality risk. Conclusions Risk factors such as resistance to carbapenems, mechanical ventilation, and presence of malignancy were found to be associated with high mortality rates in the patients with A. baumannii bacteremia.