Clinical and Molecular Characterization of Invasive Heteroresistant Vancomycin-Intermediate Staphylococcus aureus Infections in Korean Hospitals.

Invasive heteroresistant vancomycin-intermediate Staphylococcus aureus (h-VISA) isolates were identified and characterized in 10 Korean hospitals from July 2009 to June 2011. The prevalence of h-VISA infections was 3.3% (42/1,289). Most (41/42) were health care-associated infections caused by strains belonging to sequence type 5. Cases of persistent bacteremia were frequent (17/42), and 30-day mortality was high (16/40).

Characteristics of invasive Staphylococcus aureus infections in three regions of Korea, 2009-2011: a multi-center cohort study.

BACKGROUND: Despite the importance of invasive Staphylococcus aureus (ISA) infection, its overall burden in non-selected populations has only been defined in a small number of studies in Europe and North America. To define the characteristics of ISA infections in Korea, we conducted a multi-center cohort study to estimate population-based incidence rates. METHODS: We conducted a multicenter prospective cohort study at nine university-affiliated active-surveillance core centers (ASCs) in three regions of Korea. To cover all available clinical microbiologic laboratories, we classified the laboratories in these regions into three groups according to their clinical environment as: 1) Nine ASCs, 2) Five major commercial laboratories and 3) Forty-four acute-care hospital-affiliated microbiology laboratories. We requested all the laboratories to report prospectively their numbers of cases of S. aureus isolated from normally sterile sites. Detailed clinical information was collected about the cases in the nine ASCs. RESULTS: From 1 July 2009 to 30 June 2011, a total of 1,198 cases of ISA infection were identified at the nine ASCs, including 748 (62%) methicillin-resistant S. aureus (MRSA) infections. Most (81%) ISA infections were healthcare-associated (HCA): 653 (55%) hospital-onset and 322 (27%) community-onset. 223 (19%) were community-associated infections. The most common primary diagnosis was catheter-associated infection (225 cases, 19%). Respiratory tract infection (160, 13%), skin & soft tissue (152, 13%) and bone & joint infections (120, 10%) were also common. 30-day and 12-week mortality rates were 25.6% (262/1,024) and 36.5% (314/860), respectively. Complications, including metastatic infection within 12 weeks, occurred in 17.8% of ISA infections. The most common site of metastatic infection was the lung (9.8%, 84/860). Based on the total of 2,806 observed cases of ISA infection, estimated annual rates of ISA and invasive MRSA infections were 43.3 and 27.7 per 100,000 populations, respectively. CONCLUSIONS: Our data provide important information about the clinical characteristics of ISA infections. We estimate that over 21,000 ISA infections and 13,000 invasive MRSA infections occurred in Korea in 2010.

Differences in characteristics between healthcare-associated and community-acquired infection in community-onset Klebsiella pneumoniae bloodstream infection in Korea.

BACKGROUND: Healthcare-associated (HCA) infection has emerged as a new epidemiological category. The aim of this study was to evaluate the impact of HCA infection on mortality in community-onset Klebsiella pneumoniae bloodstream infection (KpBSI). METHODS: We conducted a retrospective study in two tertiary-care hospitals over a 6-year period. All adult patients with KpBSI within 48 hours of admission were enrolled. We compared the clinical characteristics of HCA and community-acquired (CA) infection, and analyzed risk factors for mortality in patients with community-onset KpBSI. RESULTS: Of 553 patients with community-onset KpBSI, 313 (57%) were classified as HCA- KpBSI and 240 (43%) as CA-KpBSI. In patients with HCA-KpBSI, the severity of the underlying diseases was higher than in patients with CA-KpBSI. Overall the most common site of infection was the pancreatobiliary tract. Liver abscess was more common in CA-KpBSI, whereas peritonitis and primary bacteremia were more common in HCA-KpBSI. Isolates not susceptible to extended-spectrum cephalosporin were more common in HCA- KpBSI than in CA-KpBSI (9% [29/313] vs. 3% [8/240]; p = 0.006). Overall 30-day mortality rate was significantly higher in HCA-KpBSI than in CA-KpBSI (22% [70/313] vs. 11% [27/240]; p = 0.001). In multivariate analysis, high Charlson's weighted index of co-morbidity, high Pitt bacteremia score, neutropenia, polymicrobial infection and inappropriate empirical antimicrobial therapy were significant risk factors for 30-day mortality. CONCLUSIONS: HCA-KpBSI in community-onset KpBSI has distinctive characteristics and has a poorer prognosis than CA-KpBSI, but HCA infection was not an independent risk factor for 30-day mortality.

Outcome of cefazolin prophylaxis for total knee arthroplasty at an institution with high prevalence of methicillin-resistant Staphylococcus aureus infection.

OBJECTIVES: The aim of this study was to evaluate the outcome of cefazolin prophylaxis for total knee arthroplasty (TKA) in a hospital with a high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection. METHODS: Since July 1, 2006, we have applied a 'care bundle' to TKA to prevent surgical site infection (SSI) without using vancomycin as antimicrobial prophylaxis, in accordance with the 1999 Hospital Infection Control Practices Advisory Committee guidelines. All patients undergoing TKA from July 1, 2006 to September 30, 2009 were enrolled. We reviewed data on SSI collected prospectively as part of routine infection control surveillance. RESULTS: Of 1323 TKAs, an SSI developed in 14 (1.06%) cases, which is comparable to the percentage obtained in other previous reports. When stratified by the National Nosocomial Infection Surveillance risk index, SSI rates were 0.86% (8/926), 1.30% (5/384), and 7.69% (1/13) in risk categories 0, 1, and 2, respectively. Of 14 SSIs, four (29%) were classified as superficial incisional, two (14%) as deep incisional, and eight (57%) as organ-space SSI. CONCLUSIONS: Our data suggest that antimicrobial prophylaxis using only cefazolin can maintain low SSI rates if other important infection management measures are employed, even where there is a high prevalence of MRSA infection.