Si Hyun Kim

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.

Epidemiology and Clinical Features of Bloodstream Infections in Hematology Wards: One Year Experience at the Catholic Blood and Marrow Transplantation Center

Background The aim of this study was to investigate the clinical features and epidemiology of bloodstream infections (BSIs) in 2 distinctive hematological wards of the Catholic Blood and Marrow Transplantation (BMT) center. Materials and Methods We retrospectively reviewed the medical data of patients who developed BSIs from June 2009 to May 2010 in 2 hematologic wards at the Catholic BMT center. Ward A is a 44-bed unit mainly conducting conventional high dose chemotherapy and ward B is a 23-bed unit exclusively conducting BMT. Results Overall, 222 BSI episodes were developed from 159 patients. Acute myeloid leukemia in ward A and multiple myeloma in ward B were more frequent than in ward B and A, respectively. Sex, age, presence of neutropenia, shock, Pitt bacteremia score, type of central catheter, level of C-reactive protein, duration of admission days, type of BSI, overall mortality and distribution of organisms were not different between the 2 wards. There were 202 monomicrobial and 20 polymicrobial BSI episodes, including 2 fungemia episodes. The incidence rate of overall BSIs per 1,000 patient-days was higher in ward A than in ward B (incidence rate ratio 2.88, 95% confidence interval 1.97-4.22, P<0.001). Among 243 organisms isolated, the number of gram positives, gram negatives and fungi were 122, 119 and 2, respectively. Escherichia coli was the most common organism in both ward A and B (27.6% and 42.4%), followed by viridians streptococci (18.6% and 15.2%) and Klebsiella pneumoniae (13.3% and 9.0%). Extended spectrum beta-lactamase (ESBL) producers accounted for 31.9% (23/72) of E. coli and 71.0% (22/31) of K. pneumoniae. Out of 19 Enterococcus faecium, 7 isolates (36.8%) were resistant to vancomycin. The crude mortality rates at 7 and 30 days after each BSI episode were 4.5% (10/222) and 13.1% (29/222), and were significantly higher in the patients with shock compared with those without shock (20.5% vs. 1.1%, P<0.001 and 38.5% vs. 7.7%, P<0.001, respectively). Conclusions The incidence rate of BSIs was higher in patients receiving chemotherapy than those receiving BMT, but the distribution of organisms was not different between the 2 wards. E. coli was the most common causative BSI organism in hematologic wards followed by viridians streptococci and K. pneumoniae.

Clinical characteristics and the usefulness of the QuantiFERON-TB Gold In-Tube test in hematologic patients with hepatic or splenic lesions

Background/Aims Hepatic or splenic lesions in hematologic patients are not defined well because they are not easy to evaluate due to limitations of invasive procedures. Management typically depends on the clinical diagnosis with few microbiological data. Methods We reviewed the medical records of consecutive hematologic patients with hepatic or splenic lesions in the infectious diseases unit from April 2009 to December 2010 at the Catholic Hematopoietic Stem Cell Transplantation Center in Korea. Results Twenty-six patients were identified. Their mean age was 46.0 ± 14.7 years, and 16 (61.5%) were male. Underlying diseases were acute myelogenous leukemia (n = 15, 57.7%) and myelodysplastic syndrome (n = 6, 23.1%). Among the nine nontuberculous infectious lesions, two bacterial, six fungal, and one combined infection were identified. The numbers of confirmed, probable, and possible tuberculosis (TB) cases were one, three, and four, respectively. Two patients had concurrent pulmonary TB. QuantiFERON-TB Gold In-Tube (QFT-GIT, Cellestis Ltd.) was positive in seven cases, among which six were diagnosed with TB. The sensitivity and specificity of QFT-GIT were 75% and 81.3%. Nine (34.6%) were defined as noninfectious causes. Conclusions Causes of hepatic or splenic lesion in hematologic patients were diverse including TB, non-TB organisms, and noninfectious origins. TB should be considered for patients not responding to antibacterial or antifungal drugs, even in the absence of direct microbiological evidence. QFT-GIT may be useful for a differential diagnosis of hepatosplenic lesions in hematologic patients.

Liver abscess caused by Brevundimonas vesicularis in an immunocompetent patient.

Invasive infections caused by Brevundimonas vesicularis are very rare in humans. We experienced an unusual case of liver abscess due to B. vesicularis in an immunocompetent young male. The patient was successfully treated by liver abscess drainage and with antimicrobial therapy of ceftriaxone followed by ampicillin/sulbactam. The organism found in the aspiration culture of the abscess material was initially reported, by using a VITEK 2 system, as Sphingomonas paucimobilis. However, later, B. vesicularis was confirmed as the true pathogen through 16S rRNA gene sequencing. To our knowledge, this is the first case of liver abscess caused by B. vesicularis.

Once-Daily Gentamicin Administration for Community- Associated Methicillin Resistant Staphylococcus aureus in an in vitro Pharmacodynamic Model: Preliminary Reports for the Advantages for Optimizing Pharmacodynamic Index

Purpose Community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infections are increasing. Although gentamicin (GEN) is usually susceptible against CA-MRSA, GEN is rarely considered for treatment as monotherapy. We employed an in vitro pharmacodynamic model (IVPDM) to compare efficacies of GEN against CA-MRSA with two dosing regimens [thrice-daily (TD), once-daily (OD)]. Materials and Methods Using two strains of CA-MRSA, we adopted IVPDM comprised of two-compartments with a surface-to-volume ratio of 5.34 cm-1. GEN regimens were simulated with human pharmacokinetic data of TD and OD. Experiments were performed over 48 hours in triplicate for each strain and dosing regimen. Results MICs of GEN for YSSA1 and YSSA15 were 1 and 2 mg/L, respectively. In OD, indices of peak/MIC were > 8.6 at least, in contrast to < 6.4 in TD. A ≥ 3-log10 reduction in CFU/mL was demonstrated prior to 4 hours in TD and OD, and continued until 8 hours for both strains. However, reductions in the colony counts at 24 and 48 hours were significantly larger for OD compared to TD in both strains (p < 0.001). During TD, resistance developed in YSSA1 and small colony variants (SCVs) were documented in YSSA15. No resistance or SCVs were observed during OD in both strains. Conclusion TD and OD showed the same killing slopes until 8 hours. After the 24 hours of experiments, OD of GEN would be advantageous not only in having more reductions in colony counts, but also suppressing the development of resistance or SCVs for 48 hours.

A Case of Pseudomembranous Colitis after Voriconazole Therapy

This is a case report on a 35-year-old man with acute myelogenous leukemia who presented fever and intermittent mucoid loose stool to the emergency center. He had been taking voriconazole for invasive pulmonary aspergillosis. The flexible sigmoidoscopy was consistent with the diagnosis of pseudomembranous colitis.