Secular trends of healthcare-associated infections at a teaching hospital in Taiwan, 1981-2007

In vitro susceptibility of common Enterobacterales to eravacycline in Taiwan

BACKGROUND

New tetracycline derivatives exhibit broad-spectrum antimicrobial activities. This study aimed to assess the in vitro activity of eravacycline against common Enterobacterales.

METHODS

Clinical Enterobacterales isolates were collected between 2017 and 2021. The minimum inhibitory concentration (MIC) was determined using a broth microdilution test.

RESULTS

We identified Klebsiella pneumoniae (n = 300), Escherichia coli (n = 300), Klebsiella oxytoca (n = 100), Enterobacter cloacae complex (n = 100), Citrobacter freundii (n = 100), and Proteus mirabilis (n = 100). All P. mirabilis strains were resistant to eravacycline. Excluding P. mirabilis, the susceptibility rates to eravacycline, omadacycline, and tigecycline were 75.2%, 66.9%, and 73%, respectively. The MIC₅₀ and MIC₉₀ (mg/L) of eravacycline were 0.5 and 4 for K. pneumoniae, 0.5 and 1 for E. coli, 0.5 and 1 for K. oxytoca, 0.5 and 2 for E. cloacae complex, and 0.25 and 1 for C. freundii. In cefotaxime non-susceptible and meropenem susceptible Enterobacterales, excluding P. mirabilis, the susceptibility rates of eravacycline, omadacycline, and tigecycline were 69.7%, 57.1%, and 66.2%. We found decreased susceptibility rates of three new tetracycline derivatives against meropenem non-susceptible Enterobacterales (eravacycline: 47.1%, omadacycline: 39.4%, and tigecycline: 39.4%). Eravacycline showed a high susceptibility rate against cefotaxime non-susceptible and meropenem susceptible K. oxytoca (100%), C. freundii (93.2%), E. coli (85.9%), and meropenem non-susceptible E. coli (100%).

CONCLUSION

This study provides the MIC and susceptibility rate of eravacycline for common Enterobacterales. Eravacycline could be a therapeutic choice for cefotaxime non-susceptible or meropenem non-susceptible Enterobacterales, especially K. oxytoca, C. freundii, and E. coli.

Synergistic Antifungal Activity of Chitosan with Fluconazole against Candida albicans, Candida tropicalis, and Fluconazole-Resistant Strains

(1) Background: Few antifungal drugs are currently available, and drug-resistant strains have rapidly emerged. Thus, the aim of this study is to evaluate the effectiveness of the antifungal activity from a combinational treatment of chitosan with a clinical antifungal drug on Candida albicans and Candida tropicalis. (2) Methods: Minimum inhibitory concentration (MIC) tests, checkerboard assays, and disc assays were employed to determine the inhibitory effect of chitosan with or without other antifungal drugs on C. albicans and C. tropicalis. (3) Results: Treatment with chitosan in combination with fluconazole showed a great synergistic fungicidal effect against C. albicans and C. tropicalis, but an indifferent effect on antifungal activity when challenged with chitosan-amphotericin B or chitosan-caspofungin simultaneously. Furthermore, the combination of chitosan and fluconazole was effective against drug-resistant strains. (4) Conclusions: These findings provide strong evidence that chitosan in combination with fluconazole is a promising therapy against two Candida species and its drug-resistant strains.

Candida tropicalis RON1 is required for hyphal formation, biofilm development, and virulence but is dispensable for N-acetylglucosamine catabolism

NDT80-like family genes are highly conserved across a large group of fungi, but the functions of each Ndt80 protein are diverse and have evolved differently among yeasts and pathogens. The unique NDT80 gene in budding yeast is required for sexual reproduction, whereas three NDT80-like genes, namely, NDT80, REP1, and RON1, found in Candida albicans exhibit distinct functions. Notably, it was suggested that REP1, rather than RON1, is required for N-acetylglucosamine (GlcNAc) catabolism. Although Candida tropicalis, a widely dispersed fungal pathogen in tropical and subtropical areas, is closely related to Candida albicans, its phenotypic, pathogenic and environmental adaptation characteristics are remarkably divergent. In this study, we focused on the Ron1 transcription factor in C. tropicalis. Protein alignment showed that C. tropicalis Ron1 (CtRon1) shares 39.7% identity with C. albicans Ron1 (CaRon1). Compared to the wild-type strain, the C. tropicalis ron1Δ strains exhibited normal growth in different carbon sources and had similar expression levels of several GlcNAc catabolic genes during GlcNAc treatment. In contrast, C. tropicalis REP1 is responsible for GlcNAc catabolism and is involved in GlcNAc catabolic gene expressions, similar to C. albicans Rep1. However, REP1 deletion strains in C. tropicalis promote hyphal development in GlcNAc with low glucose content. Interestingly, CtRON1, but not CaRON1, deletion mutants exhibited significantly impaired hyphal growth and biofilm formation. As expected, CtRON1 was required for full virulence. Together, the results of this study showed divergent functions of CtRon1 compared to CaRon1; CtRon1 plays a key role in yeast-hyphal dimorphism, biofilm formation and virulence.

LAY ABSTRACT

In this study, we identified the role of RON1, an NDT80-like gene, in Candida tropicalis. Unlike the gene in Candida albicans, our studies showed that RON1 is a key regulator of hyphal formation, biofilm development and virulence but is dispensable for N-acetylglucosamine catabolism in C. tropicalis.

Molecular characteristics and clinical features of pediatric methicillin-susceptible Staphylococcus aureus infection in a medical center in northern Taiwan

Background

There have been no reports regarding clinical features and molecular characteristics of childhood methicillin-susceptible Staphylococcus aureus (MSSA) infections in Taiwan.

Methods

We prospectively collected clinical S. aureus isolates from patients aged < 18 years in a university-affiliated hospital in 2015. Only the first isolate from each patient was included. Medical records were retrospectively reviewed. Patients were classified as community-associated (CA) or healthcare-associated (HA) by the epidemiologic criteria. All MSSA isolates were molecularly characterized.

Results

A total of 495 S. aureus isolates were identified, and 178 (36.0%) were MSSA. Among the 131 MSSA-infected patients enrolled, 94 (71.8%) were community-associated and 60 (45.8%) were inpatients. Patients with HA infections was significantly younger than those with CA infections (median, 15 vs. 67.5 months). The most common specimen of MSSA identified was pus or wound (73.3%). Compared to HA-MSSA, CA-MSSA isolates were significantly less frequently from sputum (6.4% vs. 27%, p = 0.001). Nineteen pulsotypes were identified. Four pulsotypes accounted for 60% of the isolates. Isolates of ST15/pulsotype F were more frequently seen in CA than in HA (p = 0.064) while isolates of ST188/pulsotype AX frequently seen in HA (p = 0.049). PVL genes were identified in 11 isolates (8.4%), nine of which were characterized as ST59/pulsotype D, same as the local endemic CA-MRSA clone.

Conclusions

MSSA accounted for around one-third of childhood S. aureus infections in northern Taiwan. SSTI was the most common manifestation. The molecular characteristics of these clinical MSSA isolates were relatively diverse and had certain significant differences between CA and HA isolates.

Infection preventionists' challenges in psychiatric clinical settings

BACKGROUND

Infection preventionists (IPs) play an important role in preventing health care-associated infections in a health care system. However, the limitations of the clinical setting and the unique characteristics of psychiatric patients could be barriers to effective infection prevention. The purpose of this study was to understand how IPs perceived their challenges and how these challenges negatively affect their infection prevention work in psychiatric clinical settings.

METHODS

A descriptive, qualitative research approach was used in this study. Thirteen Taiwanese psychiatric IPs were interviewed in semistructured interviews. Data were transcribed and then analyzed by thematic analysis.

RESULTS

This analysis identified 6 themes: (1) lack of preservice training in psychiatric infection control, (2) insufficient staffing in practice, (3) working within environmental limits, (4) patient noncompliance, (5) undervaluation of the importance of infection control by professionals, and (6) involvement of hospital administrators.

CONCLUSIONS

The implementation of effective infection prevention in psychiatric clinical settings may be strongly related to the factors of sufficient training and IP staffing while relying on collaboration among patients and clinical professionals and on the full support of administrators.

Quality control processes in allografting: A twenty-year retrospective review of a hospital-based bone bank in Taiwan

Musculoskeletal allografts are now commonly used. To decrease the potential risks of transmission of pathogenic bacteria, fungi, or viruses to the transplant recipients, certain issues regarding the management of patients who receive contaminated allografts need to be addressed. We aimed to clarify the incidence and extent of disease transmission from allografts by analyzing the allografting procedures performed in the bone bank of our hospital over the past 20 years. We retrospectively reviewed the data from our allograft registry center on 3979 allografts that were implanted in 3193 recipients throughout a period of two decades, from July 1991 to June 2011. The source of the allografts, results of all screening tests, dates of harvesting and implantation, and recipients of all allografts were checked. With the help of the Center for Infection Control of our hospital, a strict prospective, hospital-wide, on-site surveillance was conducted, and every patient with healthcare-associated infection was identified. Fisher’s exact test was used to compare the infection rate between recipients with sterile allografts and those with contaminated allografts. The overall discard and infection rates were, respectively, 23% and 1.3% in the first decade (1991–2001); and 18.4% and 1.25% in the second decade (2001–2011). The infection rate of contaminated allograft recipients was significantly higher than that of sterile allograft recipients (10% vs. 1.15%, P < 0.01) in the second decade. Both infection and discard rates of our bone bank are comparable with those of international bone banks. Strict allograft processing and adequate prophylactic use of antibiotics are critical to prevent infection and disease transmission in such cases.

2016 guidelines for the use of antifungal agents in patients with invasive fungal diseases in Taiwan

The Infectious Diseases Society of Taiwan, Medical Foundation in Memory of Dr. Deh-Lin Cheng, Foundation of Professor Wei-Chuan Hsieh for Infectious Diseases Research and Education, and CY Lee's Research Foundation for Pediatric Infectious Diseases and Vaccines have updated the guidelines for the use of antifungal agents in adult patients with invasive fungal diseases in Taiwan. This guideline replaces the 2009 version. Recommendations are provided for Candida, Cryptococcus, Aspergillus and Mucormycetes. The focus is based on up-to-date evidence on indications for treatment or prophylaxis of the most common clinical problems. To support the recommendations in this guideline, the committee considered the rationale, purpose, local epidemiology, and key clinical features of invasive fungal diseases to select the primary and alternative antifungal agents. This is the first guideline that explicitly describes the quality and strength of the evidence to support these recommendations. The strengths of the recommendations are the quality of the evidence, the balance between benefits and harms, resource and cost. The guidelines are not intended nor recommended as a substitute for bedside judgment in the management of individual patients, the advice of qualified health care professionals, and more recent evidence concerning therapeutic efficacy and emergence of resistance. Practical considerations for individualized selection of antifungal agents include patient factors, pathogen, site of infection and drug-related factors, such as drug-drug interaction, drug-food intervention, cost and convenience. The guidelines are published in the Journal of Microbiology, Immunology and Infection and are also available on the Society website.

2016 guideline strategies for the use of antifungal agents in patients with hematological malignancies or hematopoietic stem cell transplantation recipients in Taiwan

The Infectious Diseases Society of Taiwan (IDST), the Hematology Society of Taiwan, the Taiwan Society of Blood and Marrow Transplantation, Medical Foundation in Memory of Dr. Deh-Lin Cheng, Foundation of Professor Wei-Chuan Hsieh for Infectious Diseases Research and Education, and CY Lee's Research Foundation for Pediatric Infectious Diseases and Vaccines cooperatively published this guideline for the use of antifungal agents in hematological patients with invasive fungal diseases (IFDs) in Taiwan. The guideline is the first one endorsed by IDST focusing on selection of antifungal strategies, including prophylaxis, empirical (or symptom-driven) and pre-emptive (or diagnostic-driven) strategy. We suggest a risk-adapted dynamic strategy and provide an algorithm to facilitate decision making in population level as well as for individual patient. Risk assessment and management accordingly is explicitly emphasized. In addition, we highlight the importance of diagnosis in each antifungal strategy among five elements of the antimicrobial stewardship (diagnosis, drug, dose, de-escalation and duration). The rationale, purpose, and key recommendations for the choice of antifungal strategy are summarized, with concise review of international guidelines or recommendation, key original articles and local epidemiology reports. We point out the interaction and influence between elements of recommendations and limitation of and gap between evidences and daily practice. The guideline balances the quality of evidence and feasibility of recommendation in clinical practice. Finally, this version introduces the concept of health economics and provides data translated from local disease burdens. All these contents hopefully facilitate transparency and accountability in medical decision-making, improvements in clinical care and health outcomes, and appropriateness of medical resource allocation.

A Web-Based, Hospital-Wide Health Care-Associated Bloodstream Infection Surveillance and Classification System: Development and Evaluation

Background

Surveillance of health care-associated infections is an essential component of infection prevention programs, but conventional systems are labor intensive and performance dependent.

Objective

To develop an automatic surveillance and classification system for health care-associated bloodstream infection (HABSI), and to evaluate its performance by comparing it with a conventional infection control personnel (ICP)-based surveillance system.

Methods

We developed a Web-based system that was integrated into the medical information system of a 2200-bed teaching hospital in Taiwan. The system automatically detects and classifies HABSIs.

Results

In this study, the number of computer-detected HABSIs correlated closely with the number of HABSIs detected by ICP by department (n=20; r=.999 P<.001) and by time (n=14; r=.941; P<.001). Compared with reference standards, this system performed excellently with regard to sensitivity (98.16%), specificity (99.96%), positive predictive value (95.81%), and negative predictive value (99.98%). The system enabled decreasing the delay in confirmation of HABSI cases, on average, by 29 days.

Conclusions

This system provides reliable and objective HABSI data for quality indicators, improving the delay caused by a conventional surveillance system.

Incidence and species distribution of candidaemia in Asia: a laboratory-based surveillance study

The epidemiology of candidaemia varies between hospitals and geographic regions. Although there are many studies from Asia, a large-scale cross-sectional study across Asia has not been performed. We conducted a 12-month, laboratory-based surveillance of candidaemia at 25 hospitals from China, Hong Kong, India, Singapore, Taiwan and Thailand. The incidence and species distribution of candidaemia were determined. There were 1601 episodes of candidaemia among 1.2 million discharges. The overall incidence was 1.22 episodes per 1000 discharges and varied among the hospitals (range 0.16-4.53 per 1000 discharges) and countries (range 0.25-2.93 per 1000 discharges). The number of Candida blood isolates and the total number of fungal isolates were highly correlated among the six countries (R² = 0.87) and 25 hospitals (R² = 0.77). There was a moderate correlation between incidence of candidaemia and the intensive care unit (ICU)/total bed ratio (R² = 0.47), although ICUs contributed to only 23% of candidaemia cases. Of 1910 blood isolates evaluated, Candida albicans was most frequently isolated (41.3%), followed by Candida tropicalis (25.4%), Candida glabrata (13.9%) and Candida parapsilosis (12.1%). The proportion of C. tropicalis among blood isolates was higher in haemato-oncology wards than others wards (33.7% versus 24.5%, p 0.0058) and was more likely to be isolated from tropical countries than other Asian countries (46.2% versus 18.9%, p 0.04). In conclusion, the ICU settings contribute, at least in part, to the incidence variation among hospitals. The species distribution is different from Western countries. Both geographic and healthcare factors contribute to the variation of species distribution.

Effectiveness of tigecycline-based versus colistin- based therapy for treatment of pneumonia caused by multidrug-resistant Acinetobacter baumannii in a critical setting: a matched cohort analysis

Background

Colistin and tigecycline have both been shown good in vitro activity among multi-drug resistant Acinetobacter baumannii (MDRAB). A comparative study of colistin versus tigecycline for MDRAB pneumonia is lacking.

Methods

The study enrolled adults with MDRAB pneumonia admitted to intensive care units at a referral medical center during 2009–2010. Since there were no standardized minimum inhibitory concentration (MIC) interpretation criteria of tigecycline against A. baumannii, MIC of tigecycline was not routinely tested at our hospital. During the study periods, MIC of colistin was not routinely tested also. We consider both colistin and tigecycline as definite treatments of MDRAB pneumonia. Patients who received tigecycline were selected as potential controls for those who had received colistin. We performed a propensity score analysis, by considering the criteria of age, gender, underlying diseases, and disease severity, in order to match and equalize potential prognostic factors and severity in the two groups.

Results

A total of 294 adults with MDRAB pneumonia were enrolled, including 119 who received colistin and 175 who received tigecycline. We matched 84 adults who received colistin with an equal number of controls who received tigecycline. The two well matched cohorts share similar characteristics: the propensity scores are colistin: 0.37 vs. tigecycline: 0.37, (P = .97); baseline creatinine (1.70 vs. 1.81, P = .50), and the APACHE II score (21.6 vs. 22.0, P = .99). The tigecycline group has an excess mortality of 16.7% (60.7% vs. 44%, 95% confidence interval 0.9% – 32.4%, P = .04). The excess mortality of tigecycline is significant only among those with MIC >2 μg/mL (10/12 vs. 37/84, P = .01), but not for those with MIC ≦ 2 μg/mL (4/10 vs. 37/84, P = .81).

Conclusions

Our data disfavors the use of tigecycline-based treatment in treating MDRAB pneumonia when tigecycline and colistin susceptibilities are unknown, since choosing tigecycline-based treatment might result in higher mortality. The excess mortality of tigecycline-based group may be related to higher MIC of tigecycline (> 2 μg/mL). Choosing tigecycline empirically for treating MDRAB pneumonia in the critical setting should be cautious.

Chlorhexidine for the prevention of bloodstream infection associated with totally implantable venous ports in patients with solid cancers

PURPOSE

To evaluate the preventive effects of topical skin disinfection with chlorhexidine on bloodstream infection (BSI) associated with totally implantable venous port (Port-A).

METHODS

Two consecutive cohorts of solid cancer patients were prospectively followed for the occurrence of Port-A associated BSI (PABSI). The first cohort used povidone-iodine as topical skin disinfection and the second cohort used chlorhexidine. The primary endpoint was the time to first PABSI. Propensity score analysis was applied. The preventive effects of chlorhexidine were analyzed by Cox proportional hazards models.

RESULTS

There were 396 patients (81,752 catheter-days) in the iodine cohort and 497 (99,977 catheter-days) in the chlorhexidine cohort. Gram-negative bacteria were the most common pathogens to cause first episode of PABSI (iodine cohort (I) vs chlorhexidine cohort (C) and 0.404 vs 0.450 per 1,000 catheter-day), followed by Gram-positive bacteria (I vs C and 0.269 vs 0.110 per 1,000 catheter-day), and fungi (I vs C and 0.098 vs 0.070 per 1,000 catheter-day). Three hundred forty-three patients were selected from each cohort by propensity score match analysis. Chlorhexidine use was associated with a significant improvement on time to first PABSI caused by Gram-positive bacteria (log-rank test, p=0.00175; HR=0.35, 95 % CI, 0.14-0.85, p=0.02). No significant preventive effects of chlorhexidine on time to first PABSI caused by Gram-negative bacteria or fungi was found.

CONCLUSIONS

Chlorhexidine topical skin disinfection may prevent PABSI caused by Gram-positive bacteria in patients with solid cancers. The nonsignificant effect on preventing overall PABSI may be attributed to the high incidence of Gram-negative bacteria related PABSI.

Correlation between antimicrobial consumption and incidence of health-care-associated infections due to methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci at a university hospital in Taiwan from 2000 to 2010

Objectives

This study was conducted to investigate the correlation between antibiotic consumption and the incidence of health-care-associated infections (HCAIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) (HCAI-MRSA) and vancomycin-resistant enterococci (VREs) (HCAI-VREs) at a university hospital in Taiwan during the period from 2000 to 2010.

Methods

Data on annual patient-days and annual consumption (defined daily dose/1000 patient-days) of glycopeptides (vancomycin and teicoplanin), linezolid, fusidic acid, tigecycline, and daptomycin were analyzed. Yearly aggregated data on the number of nonduplicate clinical MRSA and VRE isolates causing HCAI were collected.

Results

Overall, the consumption of teicoplanin and linezolid significantly increased during the study period. A significant decrease in the incidence of HCAI-MRSA and a significant increase in the incidence of HCAI-VRE were found during the study period. A significant correlation was found between the increased use of teicoplanin and linezolid and the decreased incidence of HCAI-MRSA. By contrast, positive correlations were found between the consumption of teicoplanin and tigecycline and the incidence of HCAI-VRE.

Conclusion

This study identified various correlations between the consumption of antibiotics and the incidence of HCAI-MRSA and HCAI-VRE. Strict implementation of infection-control guidelines and reinforcement of administering appropriate antibiotic agents would be helpful in decreasing the incidence of MRSA and VRE in hospitals.

Anaerobes in nosocomial and community acquired pleural infections

Anaerobes are important causes of pleural space infections. The aim of the study is to evaluate the role of the anaerobic bacteria in pleural infections. The study involved 278 consecutive clinical samples sent to the Clinical Microbiology Laboratory of Tertiary Chest Hospital. Anaerobes were isolated in 39 community acquired and five nosocomial cases out of 278 anaerobic cultivations (15.8%). Total of 56 anaerobe strains were identified and 21 aerobes were accompanied to anaerobic isolates. Aerobe isolates were associated with anaerobic microorganisms in 19 cases (43.2%). Bacteroides species (21.4%) and Pseudomonas aeruginosa (33.3%) were the most common anaerobic and aerobic isolates.

Antimicrobial use, incidence, etiology and resistance patterns in bacteria causing ventilator-associated pneumonia in a clinical-surgical intensive care unit

INTRODUCTION

Antimicrobial resistance is an increasing threat in hospitalized patients, and inappropriate empirical antimicrobial therapy is known to adversely affect outcomes in ventilator-associated pneumonia (VAP). The aim of this study was to evaluate antimicrobial usage, incidence, etiology, and antimicrobial resistance trends for prominent nosocomial pathogens causing ventilator-associated pneumonia in a clinical-surgical intensive care unit (ICU).

METHODS

Gram-negative bacilli and Staphylococcus aureus causing VAP, as well as their antimicrobial resistance patterns and data on consumption (defined daily dose [DDD] per 1,000 patient days) of glycopeptides, extended-spectrum cephalosporins, and carbapenems in the unit were evaluated in two different periods (A and B).

RESULTS

Antimicrobial use was high, mainly of broad-spectrum cephalosporins, with a significant increase in the consumption of glycopeptides (p < 0.0001) and carbapenems (p < 0.007) in period B. For Acinetobacter baumannii and members of the Enterobacteriaceae family, 5.27- and 3.06-fold increases in VAPs, respectively, were noted, and a significant increase in resistance rates was found for imipenem-resistant A. baumannii (p = 0.003) and third-generation cephalosporins-resistant Enterobacteriaceae (p = 0.01) isolates in this same period.

CONCLUSIONS

Our results suggest that there is a link between antibiotics usage at institutional levels and resistant bacteria. The use of carbapenems was related to the high rate of resistance in A. baumannii and therefore a high consumption of imipenem/meropenem could play a major role in selective pressure exerted by antibiotics in A. baumannii strains.

Distribution and drug susceptibilities of Candida species causing candidemia from a medical center in central Taiwan

Invasive fungal infections have increased significantly in the past few decades because of the increase in high-risk populations. To investigate the distribution and drug susceptibilities of such infections, we analyzed all 152 Candida isolates causing candidemia from 2004 to 2006 at the China Medical University Hospital, a medical center in central Taiwan. Candida albicans was the most common species, accounting for 52.6% of the isolates, followed by C. tropicalis (19.7%), C. parapsilosis (14.5%), C. glabrata (8.6%), C. guilliermondii (3.9%), and C. pelliculosa (0.7%). All isolates were susceptible to amphotericin B, anidulafungin, micafungin, and voriconazole according to minimum inhibitory concentrations (MICs) after a 24-h incubation; 0.7%, 6.6%, and 7.9% of isolates were resistant to amphotericin B, fluconazole, and voriconazole, respectively, after 48-h incubation. Both C. albicans and C. parapsilosis had high degrees of agreement for azoles between 24- and 48-h incubation periods, whereas C. glabrata (38.5-46.2%) and C. tropicalis (56.7-63.3%) did not. The majority of the isolates with high azole MICs displayed a trailing growth phenotype. Hence, the MICs of different drugs after 24-h incubation may be considered for prognosis of candidemia.

Species distribution and drug susceptibilities of Candida isolates in TSARY 2010

Susceptibilities to antifungal drugs of 1083 Candida isolates collected in Taiwan Surveillance of Antimicrobial Resistance of Yeasts in 2010 were determined. There were 422 (39%) C. albicans, 270 (24.9%) C. tropicalis, 258 (23.8%) C. glabrata, 87 (8%) C. parapsilosis, 18 (1.7%) C. krusei, and 28 (2.6%) of 13 other species. In the present study, we have applied species-specific clinical breakpoints for common species and epidemiological cutoff values for rare species. We found that majority of isolates were susceptible to tested drugs. A total of 15, 3, 2, and 0 isolates were not susceptible to fluconazole, voriconazole, amphotericin B, and anidulafungin, respectively. We found that three of the four fluconazole non-susceptible C. albicans isolates were resistant to voriconazole. Hence, there is an issue of cross-resistance among azole-type drugs.

Predictors of bloodstream infection associated with permanently implantable venous port in solid cancer patients

BACKGROUND

The purpose of this study is to characterize the risk factors of bloodstream infection (BSI) associated with the use of permanent implantable venous ports (Port-A) in solid cancer patients.

METHODS

Solid cancer patients implanted with a Port-A were prospectively observed for the occurrence of Port-A-associated BSI (PABSI), defined as BSI without other identifiable infection foci. A PABSI risk score was developed using the Cox proportional hazards model.

RESULTS

A total of 415 patients were registered; 88 PABSI episodes occurred in 58 patients (incidence1.05 per 1000 catheter-days). All but one patient had stage IV cancer. Independent predictors of PABSI occurrence included neutropenia, total parenteral nutrition (TPN), chronic steroid use, invasive procedures, postoperative antibiotics, and preoperative antibiotics. A PABSI risk score with a cut-off value of 0 (sensitivity 88.5%, specificity 64.3%) was defined for stage IV cancer patients as follows: neutropenia, +1.350; TPN, +1.256; chronic steroid use, +1.947; preoperative antibiotics, -0.970; postoperative antibiotics, +0.959; and invasive procedures, +1.098. The median PABSI-free survival was 4.47 months for patients with scores ≥ 0 but not reached for patients with scores <0 (P < 0.0001).

CONCLUSION

The PABSI risk score can assist in identifying high-risk solid cancer patients and may assist in designing future preventive strategies.

Compliance of health care workers with hand hygiene practices: independent advantages of overt and covert observers

BACKGROUND

Evaluation and feedback of hand hygiene (HH) compliance are important elements of the WHO multimodal strategy for hospital infection control. Overt observation is recommended, but it may be confounded by Hawthorne effect. Covert observation offers the opportunity to decrease observer bias. In this study we conducted a one year hospital-wide HH promotion program that included medical students (MS) as covert observers.

METHODS

HH compliance for the five WHO indications was determined by trained and validated observers. The overt observers consisted of eleven infection control nurses (ICNs) and two unit HH ambassadors (UAs) in each of 83 wards. The covert observers consisted of nine MS during their rotating clinical clerkships. Feedback was provided to department heads and staff each quarter.

RESULTS

Of the 23,333 HH observations 76.0% were by MS, 5.3% by ICNs and 18.7% by UAs. The annual compliance rates were MS 44.1%, ICNs 74.4% and UAs 94.1%; P<0.001. The MS found significantly lower annual compliance rates for 4/5 HH indications compared to ICNs and UAs; P<0.05. The ICNs reported significantly improvement from the first to the fourth quarter; P<0.001. This was associated with feedback from the MS of very poor compliance by nurses during the first quarter.

CONCLUSIONS

Based on these findings we recommend a two-pronged approach to HH programs. The role of ICNs and UAs is to educate, serve as role models, establish, sustain good HH practices and provide direct feedback. The role of the covert observers is to measure compliance and provide independent feedback.

A Web-based multidrug-resistant organisms surveillance and outbreak detection system with rule-based classification and clustering

BACKGROUND

The emergence and spread of multidrug-resistant organisms (MDROs) are causing a global crisis. Combating antimicrobial resistance requires prevention of transmission of resistant organisms and improved use of antimicrobials.

OBJECTIVES

To develop a Web-based information system for automatic integration, analysis, and interpretation of the antimicrobial susceptibility of all clinical isolates that incorporates rule-based classification and cluster analysis of MDROs and implements control chart analysis to facilitate outbreak detection.

METHODS

Electronic microbiological data from a 2200-bed teaching hospital in Taiwan were classified according to predefined criteria of MDROs. The numbers of organisms, patients, and incident patients in each MDRO pattern were presented graphically to describe spatial and time information in a Web-based user interface. Hierarchical clustering with 7 upper control limits (UCL) was used to detect suspicious outbreaks. The system's performance in outbreak detection was evaluated based on vancomycin-resistant enterococcal outbreaks determined by a hospital-wide prospective active surveillance database compiled by infection control personnel.

RESULTS

The optimal UCL for MDRO outbreak detection was the upper 90% confidence interval (CI) using germ criterion with clustering (area under ROC curve (AUC) 0.93, 95% CI 0.91 to 0.95), upper 85% CI using patient criterion (AUC 0.87, 95% CI 0.80 to 0.93), and one standard deviation using incident patient criterion (AUC 0.84, 95% CI 0.75 to 0.92). The performance indicators of each UCL were statistically significantly higher with clustering than those without clustering in germ criterion (P < .001), patient criterion (P = .04), and incident patient criterion (P < .001).

CONCLUSION

This system automatically identifies MDROs and accurately detects suspicious outbreaks of MDROs based on the antimicrobial susceptibility of all clinical isolates.

Comparison of epidemiology and treatment outcome of patients with candidemia at a teaching hospital in Northern Taiwan, in 2002 and 2010

BACKGROUND

The incidence of candidemia varied between hospitals and different study periods. Few, if any, studies provide the reasons. This hospital-based population study aimed to describe and compare the patient population hospitalized in 2002 and 2010 and determine the disease-specific incidences of candidemia and evaluate the impact of time to initiate antifungal therapy on 30-day mortality.

PATIENTS AND METHODS

All patients hospitalized at a 2300-bed teaching hospital in Taiwan in 2002 and 2010 were analyzed for the distribution of age, sex, and type of underlying diseases (maximum of six diagnoses). All patients with blood isolates that were collected in 2002 and 2010 and yielded Candida species were included for analysis of the demographic and clinical characteristics, distribution of Candida species, length of hospital stay before candidemia, stay in the intensive care units at onset of candidemia, time of initiating systemic antifungal agent, antifungal regimen, and 30-day crude mortality.

RESULTS

In 2010, the hospitalized patients were older (p < 0.001), had a higher Charlson Comorbidity Index (p < 0.001), and more underlying disease/status, including chronic pulmonary diseases, moderate-to-severe renal diseases, leukemia, lymphoma, and gastrointestinal malignancies (p < 0.001) than those seen in 2002. Multivariate analysis identified the following host factors were associated with the occurrence of candidemia in 2010: neonate (adjust odds ratio [OR], 3.67), 45-64 year (OR, 2.18) and the elderly (OR 2.64), compared with young adult (20-44 year); patients with moderate-to-severe renal diseases (OR, 8.08), leukemia (OR, 4.58) and lymphoma (OR 3.98) and gastrointestinal malignancies (OR 2.80). The incidence density of candidemia was 0.34 and 0.41 per 1000 patient-days in 2002 and 2010, respectively (p = 0.04). The majority of characteristics of patients with candidemia and disease-specific incidences of candidemia did not differ between 2002 and 2010. Despite more patients in 2010 receiving antifungal therapy on the same day or 1 day after onset (27.5% vs. 41.2%, respectively, p = 0.002), the 30-day mortality remained high (45.9% in 2002 and 44.4% in 2010). Moreover, time to initiate antifungal therapy had no impact on 30-day mortality.

CONCLUSION

This hospital-based population study demonstrated that the incidence density of candidemia was high and increased in 2010 compared with 2002, which was at least in part due to the increase in the proportion of patients at a higher risk of candidemia. Although antifungal therapy was initiated earlier in 2010, the 30-day mortality remained high.

Surveillance on secular trends of incidence and mortality for device-associated infection in the intensive care unit setting at a tertiary medical center in Taiwan, 2000-2008: a retrospective observational study

Background

Device–associated infection (DAI) plays an important part in nosocomial infection. Active surveillance and infection control are needed to disclose the specific situation in each hospital and to cope with this problem effectively. We examined the rates of DAI by antimicrobial-resistant pathogens, and 30–day and in–hospital mortality in the intensive care unit (ICU).

Methods

Prospective surveillance was conducted in a mixed medical and surgical ICU at a major teaching hospital from 2000 through 2008. Trend analysis was performed and logistic regression was used to assess prognostic factors of mortality.

Results

The overall rate of DAIs was 3.03 episodes per 1000 device–days. The most common DAI type was catheter–associated urinary tract infection (3.76 per 1000 urinary catheter–days). There was a decrease in DAI rates in 2005 and rates of ventilator–associated pneumonia (VAP, 3.18 per 1000 ventilator–days) have remained low since then (p < 0.001). The crude rates of 30–day (33.6%) and in–hospital (52.3%) mortality, as well as infection by antibiotic-resistant VAP pathogens also decreased. The most common antimicrobial-resistant pathogens were methicillin–resistant Staphylococcus aureus (94.9%) and imipenem–resistant Acinetobacter baumannii (p < 0.001), which also increased at the most rapid rate. The rate of antimicrobial resistance among Enterobacteriaceae also increased significantly (p < 0.05). After controlling for potentially confounding factors, the DAI was an independent prognostic factor for both 30–day mortality (OR 2.51, 95% confidence interval [CI] 1.99–3.17, p = 0.001) and in–hospital mortality (OR 3.61, 95% CI 2.10–3.25, p < 0.001).

Conclusions

The decrease in the rate of DAI and infection by resistant bacteria on the impact of severe acute respiratory syndrome can be attributed to active infection control and improved adherence after 2003.

Vancomycin promotes the bacterial autolysis, release of extracellular DNA, and biofilm formation in vancomycin-non-susceptible Staphylococcus aureus

Staphylococcus aureus, an important human pathogen, is particularly adept at producing biofilms on implanted medical devices. Although antibiotic treatment of nonsusceptible bacteria will not kill these strains, the consequences should be studied. The present study focuses on investigating the effect of vancomycin on biofilm formation by vancomycin-non-susceptible S. aureus. Biofilm adherence assays and scanning electron microscopy demonstrated that biofilm formation was significantly enhanced following vancomycin treatment. Bacterial autolysis of some subpopulations was observed and was confirmed by the live/dead staining and confocal laser scanning microscopy. A significant increase in polysaccharide intercellular adhesin (PIA) production was observed by measuring icaA transcript levels and in a semi-quantitative PIA assay in one resistant strain. We show that the release of extracellular DNA (eDNA) via cidA-mediated autolysis is a major contributor to vancomycin-enhanced biofilm formation. The addition of xenogeneic DNA could also significantly enhance biofilm formation by a PIA-overproducing S. aureus strain. The magnitude of the development of the biofilm depends on a balance between the amounts of eDNA and PIA. In conclusion, sublethal doses of cell wall-active antibiotics like vancomycin induce biofilm formation through an autolysis-dependent mechanism in vancomycin-non-susceptible S. aureus.

Changing incidence and clinical manifestations of Clostridium difficile-associated diarrhea detected by combination of glutamate dehydrogenase and toxin assay in Northern Taiwan

BACKGROUND/PURPOSE

The incidence of Clostridium difficile-associated diarrhea (CDAD) is increasing worldwide. Spread of an epidemic hypervirulent strain in southern Taiwan was associated with poor outcome. This prospective study evaluates the incidence and clinical manifestation of CDAD following a hospital-wide hand hygiene promotion program in a 2,200-bed teaching hospital in northern Taiwan.

PATIENTS AND METHODS

From June 1, 2010 to October 31, 2010, a predefined protocol was used to actively survey CDAD at 11 high-risk units. Stool samples of patients with antibiotic-associated diarrhea (AAD) were submitted for stool culture and toxin A/B assay using a combined enzyme immunoassay. CDAD was diagnosed by a positive toxin assay.

RESULTS

The incidence of CDAD was 0.45/1000 patient-days and was highest in medical intensive care units (7.9/1000 patient-days), followed by hemato-oncology wards, and infectious disease wards. Occurrence of CDAD was associated with ≥3 stool pus cells per high power field (p = 0.018), prior use of metronidazole (p = 0.029), high usage of beta-lactamase stable penicillins (p = 0.046), and anaerobe-active antibiotics (p = 0.029). No attributable mortality was found. The incidence of CDAD was lower than that previously observed (1.0/1000 patient-days in 2003, p < 0.001).

CONCLUSION

This study showed a lower incidence of CDAD and absence of attributable mortality. The impact of hand hygiene promotion and other infection control measures on decreasing incidence of CDAD warrants further elucidation.

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$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.

Is methicillin-resistant Staphylococcus aureus replacing methicillin-susceptible S. aureus?

Despite extensive research on the emergence of and treatments for methicillin-resistant Staphylococcus aureus (MRSA), prior studies have not rigorously evaluated the impact of methicillin resistance on the overall incidence of S. aureus infections. Yet, there are direct clinical and research implications of determining whether methicillin-susceptible S. aureus (MSSA) infection rates remain stable in the face of increasing MRSA prevalence or whether MSSA will be replaced over time. A synthesis of prior studies indicates that the emergence of healthcare-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA) has led to an increase in the overall incidence of S. aureus infections, with MRSA principally adding to, rather than replacing, MSSA. However, colonization with CA-MRSA may at least partially replace colonization with MSSA. So far, evidence indicates that MSSA still accounts for many infections. Therefore, eradication of MRSA alone is not sufficient to address the public health burden of S. aureus.