Ki Ho Park

Development of bacteraemia or fungaemia after removal of colonized central venous catheters in patients with negative concomitant blood cultures

There are limited data on the clinical significance of positive central venous catheter (CVC) tip cultures associated with concomitant negative blood cultures performed at the time of CVC removal. A retrospective cohort study of all patients who yielded isolated positive CVC tip cultures was conducted in a tertiary-care hospital with 2200 beds during a 10-year period. All patients with isolated positive CVC tip cultures were observed for the development of subsequent bacteraemia or fungaemia between 2 and 28 days after CVC removal. An isolated positive CVC tip culture was defined as a case in which (i) a CVC tip culture yielded > or = 15 colonies using a semiquantitative culture method and (ii) at least two sets of blood samples revealed no organism at, or close to, the time of CVC removal (48 h before to 48 h after CVC removal). During the study period, 312 patients with isolated positive CVC cultures were enrolled. Eight (2.6%; 95% CI 1.2-5.1) of the 312 patients yielding isolated bacterial or fungal CVC tip cultures developed subsequent bloodstream infection (BSI) caused by the same species as that isolated from the tip culture (Staphylococcus aureus, 1: Enterococcus spp.; 2: Pseudomonas aeruginosa; and 3: Candida spp.). Among 125 patients from whose CVC tips the above four organisms were grown, seven (12.3%) of 57 patients who did not receive appropriate antibiotic therapy within 48 h after CVC removal subsequently developed BSI, but only one (1.5%) of 68 patients who did receive appropriate therapy developed BSI (OR 0.11, p 0.02).

Epidemiology and clinical features of toxigenic culture-confirmed hospital–onset Clostridium difficile infection: A multicentre prospective study in tertiary hospitals of South Korea

Hypervirulent Clostridium difficile strains, most notably BI/NAP1/027, have been increasingly emerging in Western countries as local epidemics. We performed a prospective multicentre observational study from December 2011 to May 2012 to identify recent incidences of toxigenic culture-confirmed hospital-onset C. difficile infections (CDI) and their associated clinical characteristics in South Korea. Patients suspected of having been suffering from CDI more than 48 h after admission and aged ≥20 years were prospectively enrolled and provided loose stool specimens. Toxigenic C. difficile culture (anaerobic culture+toxin A/B/binary gene PCR) and PCR ribotyping were performed in one central laboratory. We enrolled 98 toxigenic culture-confirmed CDI-infected patients and 250 toxigenic culture-negative participants from three hospitals. The incidence of toxigenic culture-confirmed hospital-onset CDI cases was 2.7 per 10,000 patient-days. The percentage of severe CDI cases was relatively low at only 3.1%. UK ribotype 018 was the predominant type (48.1%). There were no hypervirulent BI/NAP1/027 isolates identified. The independent risk factors for toxigenic culture-confirmed hospital-onset CDI were invasive procedure (odds ratio (OR) 7.3, P=0.003) and past CDI history within 3 months (OR 28.5, P=0.003). In conclusion, the incidence and severity of CDI in our study were not higher than reported in Western countries.

Two Cases of Cryptococcuria Developed as Isolated Cryptococcuria and Disseminated Cryptococcosis

Cryptococcus is an opportunistic pathogen that mainly affects immunocompromised hosts and, less frequently, immunocompetent hosts. It causes serious morbidity and mortality due to systemic infections such as meningoencephalitis and pulmonary infection. Urinary involvement of Cryptococcus is sometimes reported among cases of disseminated cryptococcosis in AIDS patients, but no such reports have been published in Korea. We report two cases of cryptococcuria that developed in a 71-year old female with diabetes and liver cirrhosis and in a 50-year old male who received a liver transplant due to HBV-associated hepatic failure. The female patient had received prednisolone for 12 days before we detected C. neoformans in urine culture. Even though no antifungal therapy was indicated for cryptococcuria, following urine culture became negative, but still positive for cryptococcal antigen on hospital day 25. Her blood, CSF culture, and antigen tests were negative, and therefore she was diagnosed with isolated cryptococcuria. The male patient had received prednisolone and tacrolimus for 10 days before sputum and urine cultures became positive for C. neoformans. He had ill defined nodules and pleural effusion in both lungs on chest CT. His cryptococcuria was sustained for over 2 months, despite receiving amphotericin B treatment. His cryptococcuria seemed to be a symptom of disseminated cryptococcosis. (Korean J Clin Microbiol 2011;14:148-152)

Prevalence and impact of extended-spectrum β-lactamase production on clinical outcomes in cancer patients with Enterobacter species bacteremia

Background/Aims We examined the prevalence of extended-spectrum β-lactamase (ESBL) production and the impact of ESBL on clinical outcomes in cancer patients with Enterobacter spp. bacteremia. Methods Using prospective cohort data on Enterobacter bacteremia obtained between January 2005 and November 2008 from a tertiary care center, the prevalence and clinical impact of ESBL production were evaluated. Results Two-hundred and three episodes of Enterobacter spp. bacteremia were identified. Thirty-one blood isolates (15.3%, 31/203) scored positive by the double-disk synergy test. Among 17 isolates in which ESBL genes were detected by polymerase chain reaction and sequencing, CTX-M (n = 12), SHV-12 (n = 11), and TEM (n = 4) were the most prevalent ESBL types. Prior usage of antimicrobial agents (77.4% vs. 54.0%, p = 0.02) and inappropriate empirical antimicrobial therapy (22.6% vs. 3.0%, p < 0.001) were more commonly encountered in the ESBL-positive group than in the extended-spectrum cephalosporin-susceptible ESBL-negative group, respectively. Clinical outcomes did not differ significantly between the two groups (30-day mortality rate, 19.4% vs. 17.0%, p = 0.76; median length of hospital stay, 24.0 days vs. 30.5 days, p = 0.97). Initial presentation of severe sepsis/septic shock, pneumonia, and intra-abdominal infection were independently associated with 30-day mortality. Conclusions The prevalence of ESBL-producing isolates was 15.3% in cancer patients with Enterobacter bacteremia. Although inappropriate empirical therapy was more common in the ESBL-positive group, ESBL production was not associated with poorer outcomes.