Hsieh-Shong Leu

Secular trends in incidence and antimicrobial resistance among clinical isolates of salmonella at a university hospital in Taiwan, 1983-1999

The incidence and antimicrobial resistance among clinical isolates of salmonella at a university hospital in Taiwan between 1983 and 1999 are summarized in this report. A total of 7986 isolates were analysed. Serogroup B has been the most prevalent over the years, with an apparently continuous decline after 1995. Concordant decrease was also found among S. choleraesuis and S. typhi isolates in recent years. In contrast, the proportion of serogroup D strains increased significantly after 1996. S. typhi remained relatively susceptible to most of the antimicrobial agents examined. For non-typhoidal isolates, antimicrobial resistance to ampicillin (62%), chloramphenicol (67%), and sulfamethoxazole-trimethoprim (37%) was relatively higher than that reported elsewhere. Newer generation cephalosporins and fluoroquinolones remained effective over the years, although emerging resistance to these drugs has been noticed since 1992. A more prudent selection and use of antimicrobial agents, in both humans and animals, and a continuous surveillance of resistance are essential in the future.

Multidrug resistant Acinetobacter baumannii: risk factors for appearance of imipenem resistant strains on patients formerly with susceptible strains.

Background Multidrug resistant Acinetobacter baumannii (MDRAB) is an important nosocomial pathogen usually susceptible to carbapenems; however, growing number of imipenem resistant MDRAB (IR-MDRAB) poses further clinical challenge. The study was designed to identify the risk factors for appearance of IR-MDRAB on patients formerly with imipenem susceptible MDRAB (IS-MDRAB) and the impact on clinical outcomes. Methodology/Principal Findings A retrospective case control study was carried out for 209 consecutive episodes of IS-MDRAB infection or colonization from August 2001 to March 2005. Forty-nine (23.4%) episodes with succeeding clinical isolates of IR-MDRAB were defined as the cases and 160 (76.6%) with all subsequent clinical isolates of IS-MDRAB were defined as the controls. Quantified antimicrobial selective pressure, “time at risk”, severity of illness, comorbidity, and demographic data were incorporated for multivariate analysis, which revealed imipenem or meropenem as the only significant independent risk factor for the appearance of IR-MDRAB (adjusted OR, 1.18; 95% CI, 1.09 to 1.27). With selected cases and controls matched to exclude exogenous source of IR-MDRAB, multivariate analysis still identified carbapenem as the only independent risk factor (adjusted OR, 1.48; 95% CI, 1.14 to 1.92). Case patients had a higher crude mortality rate compared to control patients (57.1% vs. 31.3%, p = 0.001), and the mortality of case patients was associated with shorter duration of “time at risk”, i.e., faster appearance of IR-MDRAB (adjusted OR, 0.9; 95% CI, 0.83 to 0.98). Conclusions/Significance Judicious use of carbapenem with deployment of antibiotics stewardship measures is critical for reducing IR-MDRAB and the associated unfavorable outcome.

Diagnosis and treatment of pyogenic psoas abscess in diabetic patients: usefulness of computed tomography and gallium-67 scanning

OBJECTIVES To examine retrospectively the clinical presentations, microbiologic characteristics, and treatment outcomes of psoas abscess in patients with diabetes mellitus (DM) and to assess the usefulness of computed tomography and gallium-67 scanning in its early diagnosis. METHODS During a 9-year period, psoas abscesses in patients with DM were collected at a medical center. The clinical history and associated etiologic factors, microbiologic results, clinical outcomes, and hospitalization days were recorded. The use of imaging in the diagnosis of psoas abscess and other concomitant infectious lesions was also studied. RESULTS Fifteen patients with DM and psoas abscess (13 women and 2 men; mean age 58.7 +/- 9.0 years) were found. The most frequent symptom was fever (12 of 15). Of the six different microorganisms that grew in the blood and/or abscess cultures, Staphylococcus aureus was the most frequent (7 of 15). The most commonly associated pathologic finding was vertebral osteomyelitis (5 of 15). Computed tomography and/or magnetic resonance imaging confirmed the diagnosis of psoas abscesses in all 15 patients. The gallium-67 scan especially aided in the diagnosis of the patients who had initially been diagnosed as having fever of unknown origin (4 of 5) and in the diagnosis of concomitant lesions (9 of 12). Debridement or surgical drainage of the abscess was done in 12 patients. All the patients received adequate antibiotic treatment. However, the mortality rate was 20%. The average hospitalization stay was 42.7 +/- 20.7 days. CONCLUSIONS Psoas abscess in patients with DM is a disease with both diagnostic and therapeutic challenges. We found the infecting microorganisms to be variable and the mortality rate high.

Fish Tank Granuloma Caused by Mycobacterium marinum

Introduction Mycobacterium marinum causes skin and soft tissue, bone and joint, and rare disseminated infections. In this study, we aimed to investigate the relationship between treatment outcome and antimicrobial susceptibility patterns. A total of 27 patients with M. marinum infections were enrolled. Methods Data on clinical characteristics and therapeutic methods were collected and analyzed. We also determined the minimum inhibitory concentrations of 7 antibiotics against 30 isolates from these patients. Results Twenty-seven patients received antimycobacterial agents with or without surgical debridement. Eighteen patients were cured, 8 failed to respond to treatment, and one was lost to follow-up. The duration of clarithromycin (147 vs. 28; p = 0.0297), and rifampicin (201 vs. 91; p = 0.0266) treatment in the cured patients was longer than that in the others. Surgical debridement was performed in 10 out of the 18 cured patients, and in 1 of another group (p = 0.0417). All the 30 isolates were susceptible to clarithromycin, amikacin, and linezolid; 29 (96.7%) were susceptible to ethambutol; 28 (93.3%) were susceptible to sulfamethoxazole; and 26 (86.7%) were susceptible to rifampicin. However, only 1 (3.3%) isolate was susceptible to doxycycline. Discussion Early diagnosis of the infection and appropriate antimicrobial therapy with surgical debridement are the mainstays of successful treatment. Clarithromycin and rifampin are supposed to be more effective agents.

Clinical manifestations, antibiotic susceptibility and molecular analysis of Mycobacterium kansasii isolates from a university hospital in Taiwan

OBJECTIVES Mycobacterium kansasii causes a variety of infections. Although previous reports on the prognosis of antimicrobial therapy have been mostly satisfactory, problems involving treatment failure or relapse have been encountered. The purpose of this study was to establish a relationship between the clinical treatment outcomes of M. kansasii infections and bacterial drug susceptibility, and their clonality. METHODS A total of 37 M. kansasii clinical isolates and clinical information on 34 patients were retrospectively collected in a tertiary medical centre in Taiwan. Bacterial drug susceptibility was determined by the microdilution method. The phylogenetic relationship was analysed by PFGE analysis. RESULTS Results of PFGE typing revealed a major cluster (cluster I) and eight other divergent patterns. Two/three strains leading to treatment failure were also multidrug resistant and belonged to cluster I. CONCLUSIONS A relationship between high drug resistance and genetic relatedness of some M. kansasii strains was established. This was associated with clinical treatment failure.

Characteristics and outcomes of Fusobacterium nucleatum bacteremia—a 6-year experience at a tertiary care hospital in northern Taiwan

Fusobacterium nucleatum bacteremia is critical and not well defined. To identify the clinical characteristics and outcomes, we conducted a retrospective review of hospitalized patients from January 2004 to December 2009 at a tertiary center in northern Taiwan. Fifty-seven patients were enrolled. The mean age was 58.1 years, and the mean Pitt bacteremia score was 4.7. Males predominated (59.6%), and the overall 30-day mortality rate was up to 47.4%. Malignancy was the major comorbidity (26/57, 45.6%), especially oropharyngeal and gastrointestinal cancers (19/26, 73.1%). Pneumonia (17/57, 29.8%) was the most common presentation with high rates of respiratory failure (15/17, 88.2%) and mortality (11/17, 64.7%), followed by intra-abdominal infections (7/57, 12.3%). In multivariate analysis, higher Pitt bacteremia score, nosocomial infection, anemia, and intensive care unit stay were the independent factors for 30-day mortality. Nosocomial F. nucleatum bacteremia was a significant mortality predictor independent to other parameters of disease severities.

Synergy of imipenem/colistin methanesulfonate combinations against imipenem-nonsusceptible multidrug-resistant Acinetobacter baumannii

BACKGROUND The optimal combination ratio of imipenem to colistin methanesulfonate (CMS) against imipenem-nonsusceptible multidrug-resistant Acinetobacter baumannii (INS-MDRAB) has not been determined in previous studies. To provide an alternative therapeutic option for clinical INS-MDRAB isolates, we investigated whether clinically achievable serum concentrations of CMS in combination with imipenem enhance the in vitro activity of imipenem against the INS-MDRAB isolates. MATERIALS AND METHODS Fifty-nine INS-MDRAB isolates with imipenem minimal inhibitory concentration (MIC) values of ≥8 mg/L were selected randomly from the Clinical Microbiology Laboratory at a university-affiliated medical center between July 1998 and May 2005. The in vitro activity of imipenem among these 59 clinical isolates was explored via serial two-fold dilutions containing a range of imipenem concentration from 0.125 mg/L to 256 mg/L, in combination with two fixed CMS concentrations at 0.5 mg/L and 1 mg/L. Genotype classification was performed using the pulsed-field gel electrophoresis method and infrequent-restriction-site polymerase chain reaction. RESULTS A significant reversal of imipenem resistance (i.e., MICs ≤ 4 mg/L) was observed in 34 (57.6%) isolates and 44 (74.6%) isolates with the tests of CMS concentrations at 0.5 mg/L and 1 mg/L, respectively (p = 0.041). Genotype 1 was predominant (43 isolates, 72.9%) with imipenem resistance reversal rates of 51.2% and 79.1% (p = 0.004) in the tests of CMS at 0.5 mg/L and 1 mg/L, respectively. CONCLUSION The synergy of imipenem/CMS against INS-MDRAB was significantly better for the CMS concentration at 1 mg/L than that at 0.5 mg/L, especially in our predominant clone. Our results provided insightful information for treating INS-MDRAB infections in clinical practice.

Outbreak of Serratia marcescens postsurgical bloodstream infection due to contaminated intravenous pain control fluids.

BACKGROUND Serratia marcescens is an important nosocomial pathogen causing significant outbreaks. Here we report an outbreak of bloodstream infection caused by S. marcescens at a 3500-bed hospital in Taiwan. The effective cooperative efforts of both laboratory personnel and infection control practitioners (ICPs) jointly contributed to the total control of the outbreak. METHODS A sudden increase in the isolation of S. marcescens from blood cultures was noted in the Clinical Microbiology Laboratory. The information was passed to the ICPs and an investigation was initiated. Pulsed-field gel electrophoresis was used to study the relationships among the isolates. RESULTS Pulsotype A was identified in 43 (82.7%) of the 52 blood isolates studied. They were isolated from 52 patients distributed across 22 wards that were surveyed by seven ICPs. All patients had undergone surgery before the infection, and fentanyl-containing intravenous fluids were used for pain control in 43 of them. Isolates from 42 belonged to pulsotype A. Three S. marcescens isolates, all from fentanyl-containing fluids and demonstrating pulsotype A, were identified from 251 environmental cultures. All fentanyl-containing fluids that were in use were withdrawn and the outbreak was stopped. CONCLUSIONS The outbreak of S. marcescens bloodstream infection apparently occurred through the use of fentanyl-containing fluids contaminated by a pulsotype A S. marcescens.

Molecular concordance of concurrent Candida albicans candidemia and candiduria

The significance of candiduria remains unclear. We correlated Candida albicans candidemia with candiduria by molecular genotyping. 33 pairs of concurrent blood and urine C. albicans isolates from 31 adult (≥ 18 years) were genotyped with infrequent-restriction-site PCR. The molecular concordance rates of three major genotypes were 100% for I, 82% for II, and 71% for III. The molecular concordance between concurrent C. albicans candidemia and candiduria was frequent. Our findings substantiate the importance of candiduria in appropriate clinical context as the majority of our patients were from intensive care units.

Lymphocyte subsets and viral load in male AIDS patients with major depression: Naturalistic study

Abstract  This study investigated the relationships between lymphocyte subsets and viral load in AIDS patients with and without major depression. During a 7‐year period, a total of 60 male hospitalized AIDS patients were recruited in this study. The diagnosis of major depression in patients was made by the same psychiatrist according to the 4th edition of the Diagnostic and Statistical Manual for Mental Disorders criteria. All patients had data for CD4, CD8 and CD4/CD8, and only 42 patients had viral load data. Of 60 AIDS patients, 32 patients had received highly active antiretroviral therapy and received subsequent assessment of lymphocyte cell counts 1 month later. Using ancova with age adjustment, the authors found that patients with major depression (n = 22) had significantly lower CD8 cell counts than patients without major depression (n = 38). However, CD4 cell counts and CD4/CD8 ratios were not significantly different between these two groups. In addition, there was no significant difference in viral load between patients with major depression (n = 16) and patients without major depression (n = 26). Of 32 patients received highly active antiretroviral therapy, 14 patients with an antidepressant (e.g. fluoxetine 20 mg/day) had significantly decreased CD4 and not CD8 cell counts and significantly reduced CD4/CD8 ratios during a period of 1 month. In conclusion, these results suggest that AIDS patients with major depression had significantly lower CD8 cell counts and might have a more severe inflammation/immunity reaction than patients without major depression.