Jann-Tay Wang

Comparison of Both Clinical Features and Mortality Risk Associated with Bacteremia due to Community-Acquired Methicillin-Resistant Staphylococcus aureus and Methicillin-Susceptible S. aureus

BACKGROUND The majority of research about community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection has focused on skin and soft-tissue infections. No literature has been published on the clinical features and outcomes of adult patients with CA-MRSA bacteremia in comparison with patients with community-acquired methicillin-susceptible S. aureus (CA-MSSA) bacteremia. METHODS From 1 January 2001 through 31 December 2006, the demographic data and outcome of 215 consecutive adult patients admitted to a tertiary care center in Taiwan with S. aureus bacteremia (age, >16 years) who fulfilled the criteria for community-acquired S. aureus bacteremia were collected for analysis. RESULTS The mean age (+/-SD) was 56.8+/-20.5 years. There were 30 patients (14%) with CA-MRSA bacteremia and 185 (86%) patients with CA-MSSA bacteremia. Cutaneous abscess (odds ratio, 5.46; 95% confidence interval, 1.66-17.94) and necrotizing pneumonia (odds ratio, 24.81; 95% confidence interval, 2.63-234.03) were the independent predictors of CA-MRSA bacteremia; endovascular infection was the only independent predictor of CA-MSSA bacteremia. After Cox regression analysis, the independent significant risk factors for 30-day mortality included increased age, shock, and thrombocytopenia (<100,000 cells/microL). After adjustment, the day 30 mortality of patients with CA-MRSA bacteremia was not significantly higher than that of patients with CA-MSSA bacteremia (adjusted hazard ratio, 1.01; 95% confidence interval, 0.30-3.39; P = .986). Most (92%) of 25 available CA-MRSA isolates were multilocus sequence typing 59. CONCLUSIONS The number of adult patients with CA-MRSA bacteremia increased with time, and the disease was associated with more necrotizing pneumonia and cutaneous abscess but less endovascular infection than was CA-MSSA bacteremia. Patients with CA-MRSA bacteremia did not have higher mortality than did patients with CA-MSSA, even though most of the patients with CA-MRSA bacteremia did not receive empirical glycopeptide therapy.

Influence of Genospecies of Acinetobacter baumannii Complex on Clinical Outcomes of Patients with Acinetobacter Bacteremia

BACKGROUND acinetobacter baumannii complex infections are increasing in prevalence and are associated with a high mortality. Biochemical classification tests cannot differentiate A. baumannii (genospecies 2) from other genospecies. Genospecies typing offers a potential tool to determine whether there are major differences in pathogenicity among the genospecies. METHODS adult patients with A. baumannii complex bacteremia in intensive care units were prospectively observed from January 2007 through July 2009. A. baumannii complex was identified by biochemical methods and the Phoenix bacterial identification system. Genospecies were identified by 16S-23S ribosomal RNA intergenic-spacer sequencing. RESULTS among the 135 patients with A. baumannii complex bacteremia, 87 (64.4%) had isolates that belonged to genospecies 2, 36 (26.7%) had isolates that belonged to genospecies 13TU, and 12 (8.9%) had isolates that belonged to genospecies 3. Patients with A. baumannii (genospecies 2) bacteremia were more likely to have pneumonia than were patients with bacteremia due to genospecies 13TU (63.2 % vs 27.8%; P =.001), whereas patients with bacteremia due to genospecies 13TU were more likely to have primary bacteremia (69.4% vs 20.7%; P <.001). Genospecies 2 was less susceptible to antibiotics than were other genospecies. It was associated with a higher rate of mortality than was genospecies 13TU (58.6% vs 16.7%; P < .001). On multivariate analysis, genospecies 2 was an independent predictor of mortality (odds ratio, 5.46; 95% confidence interval, 2.00-14.91; P = .001). CONCLUSIONS genospecies 2 of the A. baumannii complex was associated with greater resistance to antibiotics and higher mortality among bacteremic patients, compared with other genospecies, especially genospecies 13TU. These findings emphasize the need to focus on genospecies to better understand the pathogenesis and epidemiology of infections caused by the A. baumannii complex.

Helicobacter pylori infection in a randomly selected population, healthy volunteers, and patients with gastric ulcer and gastric adenocarcinoma. A seroprevalence study in Taiwan.

To investigate the association of Helicobacter pylori and gastric ulcer and adenocarcinoma, IgG antibodies against H. pylori were examined in 823 randomly selected subjects, 92 healthy volunteers, 117 patients with gastric ulcer, and 148 with gastric adenocarcinomas in Taiwan, where the prevalence of gastric adenocarcinoma is high. The seropositivity of this population in Taiwan was 54.4%. Gastric ulcer patients had a higher seropositivity (83.8%) than healthy volunteers (62.0%) and gastric adenocarcinoma patients (62.2%) (P < 0.001). Gender difference, blood type, and habit of smoking were not associated with the seroprevalence in any study groups. Gastric ulcer coexistent with duodenal ulcer had a higher seropositivity (94.7%) (P < 0.05). The seropositivity of H. pylori in gastric adenocarcinoma patients was higher than in healthy volunteers only in younger age and was not associated with histologic type, invasion, and location of major tumors. The results reemphasize the association of H. pylori infection with gastric ulcer but not with gastric adenocarcinoma in Taiwan.

Impact of Chronic Hepatitis B Virus (HBV) Infection on Outcomes of Patients Infected with HIV in an Area Where HBV Infection Is Hyperendemic

Between June 1994 and February 2003, a total of 111 human immunodeficiency virus (HIV)-infected patients with chronic hepatitis B virus (HBV) coinfection and 387 HIV-infected patients without HBV or hepatitis C virus coinfection were prospectively observed to assess the impact of HBV infection on outcomes of HIV-infected patients. After a median duration of observation of 25 months, coinfected patients were more likely to develop hepatitis (adjusted hazard ratio [AHR], 2.54; 95% confidence interval [CI], 1.69-3.82) and hepatic decompensation (adjusted odds ratio [AOR], 9.94; 95% CI, 1.89-52.35). Although similar proportions of the 2 patient groups had an increase in the CD4 count by > or =100x10(6) cells/L (AOR, 0.78; 95% CI, 0.45-1.36) and development of new opportunistic illnesses (AOR, 0.94; 95% CI, 0.53-1.66), HBV-infected patients had an increased risk for virologic failure (AOR, 1.76; 95% CI, 1.03-2.99) and death (AHR, 1.71; 95% CI, 1.19-2.47) after highly active antiretroviral therapy was initiated.

Loss of heterozygosity at chromosome 13q in hepatocellular carcinoma: identification of three independent regions

Loss of heterozygosity (LOH) on chromosome 13q is one of the most common genetic alterations in hepatocellular carcinoma (HCC) and might be involved in liver cancer development through inactivation of tumour suppressor genes. In order to narrow down the region of 13q loss, we examined the pattern of loss of heterozygosity (LOH) in tumours from 88 HCC patients, using 18 microsatellite markers on 13q. Thirty-eight of the 88 tumours (43%) showed LOH for at least one marker. Of these, two tumours (5%) showed 13q whole arm allelic loss, while the remaining 36 tumours (95%) had partial allelic loss. The LOH pattern defined by the 36 tumours suggested the existence of at least three different smallest common deleted regions which might be involved in the carcinogenesis of HCC. The first, the most centromeric in the 13q12.3 is, close to the BRCA2 gene, defined by D13S171; the second, the most telomeric region in the 13q31-32 band, is defined by D13S154 and D13S157; the third, the intermediate region at 13q14.3, which is near the RB gene, is defined by loci D13S268. The rate of LOH at 13q31-32 was significantly higher in Hepatitis B-surface antigen (HBsAg)-positive patients than HBsAg-negative HCC patients, pointing to a candidate gene related to the development of HBsAg-positive HCCs.

Longitudinal analysis of chlorhexidine susceptibilities of nosocomial methicillin-resistant Staphylococcus aureus isolates at a teaching hospital in Taiwan

BACKGROUND Chlorhexidine has been widely used for hand hygiene to prevent transmission of nosocomial pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). However, data on longitudinal surveillance of the susceptibility of MRSA isolates to chlorhexidine are limited. METHODS A total of 240 nosocomial MRSA isolates obtained in 1990, 1995, 2000 and 2005 at National Taiwan University Hospital (NTUH), a hospital where chlorhexidine gluconate was used for hand hygiene for more than 20 years, were included in the study. Chlorhexidine susceptibility, molecular typing using multilocus sequence typing and distribution of the qacA/B gene of these MRSA isolates were studied. RESULTS The proportion of tested MRSA with a high MIC of chlorhexidine (>or=4 mg/L) was 1.7% in 1990, 50% in 1995, 40% in 2000 and 46.7% in 2005. Among these 83 isolates with high chlorhexidine MICs, 55.4% carried the qacA/B gene. MRSA isolates carrying the qacA/B gene were first detected in 1995 and belonged to a single clone at that time. However, the qacA/B gene was detected in MRSA isolates belonging to seven different clones in 2005. CONCLUSIONS The proportion of tested MRSA isolates with high chlorhexidine MICs at NTUH increased from 1990 to 1995 and remained steady thereafter. The presence of the qacA/B gene may contribute to the spread of specific MRSA clones.

Evaluation of antiseptic-impregnated central venous catheters for prevention of catheter-related infection in intensive care unit patients.

Central venous catheterization represents a significant medical advancement, particularly in the treatment of critical ill. However, there is a high risk of central venous catheters-related infection. A novel antiseptic central venous catheter, made of polyurethane and impregnated with chlorhexidine and silver sulfadiazine, was developed to reduce the risk of catheters-related infection. In this study, we did a randomized clinical study to determine the efficacy by using antiseptic catheters for the prevention of central venous catheters-related infection in the intensive care units. A total of 204 patients with 235 central venous catheters were studied at the surgical intensive care units at National Taiwan University Hospital between November 1998 and June 1999. Participants received either a standard triple-lumen polyurethane catheter or an antiseptic catheter (Arrow International, Reading, Pennsylvania, USA). Both were indistinguishable from each other. Compared to standard polyurethane catheters, antiseptic catheters were less likely to be colonized by microorganisms when they were cultured at the removal (8.0 versus 20.0 colonized catheters per 100 catheters; relative risk 0.34 [95% CI, 0.15 to 0.74]; p<0.01). There was no significant differences between both groups in catheter-related infections (0.9 versus 4.9 infections per 100 catheters; relative risk 0.17 [95% CI, 0.03 to 1.15]; p = 0.07). Gram-positive cocci and fungi were more likely to colonize in the standard polyurethane catheters (p = 0.06 and 0.04, compared to antiseptic catheters respectively). Two of our cases in the control group died directly due to catheter-related candidemia. No adverse reactions such as hypersensitivity or leukopenia were found in the antiseptic catheter group. Our study showed that central venous catheters with antiseptic coating were safe and had less risk of colonization of bacteria and fungi than standard catheters in the critically ill patients.

Effectiveness and Limitations of Hand Hygiene Promotion on Decreasing Healthcare–Associated Infections

Background Limited data describe the sustained impact of hand hygiene programs (HHPs) implemented in teaching hospitals, where the burden of healthcare-associated infections (HAIs) is high. We use a quasi-experimental, before and after, study design with prospective hospital-wide surveillance of HAIs to assess the cost effectiveness of HHPs. Methods and Findings A 4-year hospital-wide HHP, with particular emphasis on using an alcohol-based hand rub, was implemented in April 2004 at a 2,200-bed teaching hospital in Taiwan. Compliance was measured by direct observation and the use of hand rub products. Poisson regression analyses were employed to evaluate the densities and trends of HAIs during the preintervention (January 1999 to March 2004) and intervention (April 2004 to December 2007) periods. The economic impact was estimated based on a case-control study in Taiwan. We observed 8,420 opportunities for hand hygiene during the study period. Compliance improved from 43.3% in April 2004 to 95.6% in 2007 (p<.001), and was closely correlated with increased consumption of the alcohol-based hand rub (r = 0.9399). The disease severity score (Charlson comorbidity index) increased (p = .002) during the intervention period. Nevertheless, we observed an 8.9% decrease in HAIs and a decline in the occurrence of bloodstream, methicillin-resistant Staphylococcus aureus, extensively drug-resistant Acinetobacter baumannii, and intensive care unit infections. The intervention had no discernable impact on HAI rates in the hematology/oncology wards. The net benefit of the HHP was US

Safety and efficacy of intravenous colistin (colistin methanesulphonate) for severe multidrug-resistant Gram-negative bacterial infections

5,289,364, and the benefit-cost ratio was 23.7 with a 3% discount rate. Conclusions Implementation of a HHP reduces preventable HAIs and is cost effective.

Nosocomial methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in Taiwan: Mortality analyses and the impact of vancomycin, MIC = 2 mg/L, by the broth microdilution method

Multidrug-resistant (MDR) bacterial infections are increasing in Taiwan hospitals, prompting the common use of colistin. In this study, the safety and efficacy of intravenous (i.v.) colistin was assessed. The medical records of patients receiving colistin for treatment of MDR Gram-negative bacterial infections between January 2006 and September 2008 at a Taiwan medical centre were reviewed retrospectively. Demographics, clinical presentation, causative organism, adverse events and outcomes were recorded. Of the 115 patient records analysed, 74 patients (64%) were treated in the Intensive Care Unit. Common underlying diseases were hypertension (49%), chronic pulmonary disease (46%), chronic kidney disease (33%) and malignancy (31%). Lower respiratory tract infections were most common (71%), followed by primary bloodstream infections (12%), urinary tract infections (8.7%) and others (7.8%). Successful treatment with i.v. colistin against MDR Gram-negative bacterial infections occurred in 59 patients (51%). Multivariate analysis showed that a higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio=1.14; 95% confidence interval 1.02-1.28; P=0.02) was independently associated with a poor clinical response. Overall, 12 (14%) of 84 patients presented nephrotoxicity and 4 patients (3.5%) had neurotoxicity. In conclusion, colistin is an effective antimicrobial agent for severe infections caused by MDR Gram-negative bacteria. Clinical outcomes are associated with the severity of infection and underlying diseases. Compared with previous reports, this study showed a lower incidence of nephrotoxicity and neurotoxicity.