The impact of hospital-acquired bloodstream infections

Effectiveness of Minocycline and Rifampin vs Chlorhexidine and Silver Sulfadiazine-Impregnated Central Venous Catheters in Preventing Central Line-Associated Bloodstream Infection in a High-Volume Academic Intensive Care Unit: A Before and after Trial

BACKGROUND

Use of chlorhexidine and silver sulfadiazine-impregnated (CSS) central venous catheters (CVCs) has not been shown to decrease the catheter-related bloodstream infection rate in an ICU. The purpose of this study was to determine if use of minocycline and rifampin-impregnated (MR) CVCs would decrease central line-associated bloodstream infection (CLABSI) rates compared with those observed with use of CSS-impregnated CVCs.

STUDY DESIGN

A total of 7,181 patients were admitted to a 24-bed university hospital surgical ICU: 2,551 between March 2004 and August 2005 (period 1) and 4,630 between April 2006 and July 2008 (period 2). All patients requiring CVC placement in period 1 had a CSS catheter inserted, and in period 2 all patients had MR CVCs placed.

RESULTS

Twenty-two CLABSIs occurred during 7,732 catheter days (2.7 per 1,000 catheter days) in the 18-month period when CSS lines were used. After the introduction of MR CVCs, 21 catheter-related bloodstream infections occurred during 15,722 catheter days (1.4 per 1,000 catheter days). This represents a significant (p < 0.05) decrease in the CLABSI rate after introduction of MR CVCs. Mean length of time to infection developing after catheterization (8.6 days for CSS vs 6.1 days for MR) was also different (p = 0.04). The presence of MR did not alter the microbiologic profile of catheter-related infections, and it did not increase the incidence of resistant organisms.

CONCLUSIONS

The CLABSI rate decreased more with the use of MR CVCs compared with CSS CVCs in an ICU where the CLABSI rate was already low. The types of organisms causing infection were similar. With continued use of MR-impregnated CVCs in our ICU in the subsequent 5 years, we have seen sustained low rates of CLABSIs.

Performance of Gram staining on blood cultures flagged negative by an automated blood culture system

Blood is one of the most important specimens sent to a microbiology laboratory for culture. Most blood cultures are incubated for 5-7 days, except in cases where there is a suspicion of infection caused by microorganisms that proliferate slowly, or infections expressed by a small number of bacteria in the bloodstream. Therefore, at the end of incubation, misidentification of positive cultures and false-negative results are a real possibility. The aim of this work was to perform a confirmation by Gram staining of the lack of any microorganisms in blood cultures that were identified as negative by the BACTEC™ FX system at the end of incubation. All bottles defined as negative by the BACTEC FX system were Gram-stained using an automatic device and inoculated on solid growth media. In our work, 15 cultures that were defined as negative by the BACTEC FX system at the end of the incubation were found to contain microorganisms when Gram-stained. The main characteristic of most bacteria and fungi growing in the culture bottles that were defined as negative was slow growth. This finding raises a problematic issue concerning the need to perform Gram staining of all blood cultures, which could overload the routine laboratory work, especially laboratories serving large medical centers and receiving a large number of blood cultures.

Bioassay Guided Fractionation of an Anti-Methicillin-Resistant Staphylococcus aureus Flavonoid From Bromus inermis Leyss Inflorescences

Background:

Plants are considered as promising sources of new antibacterial agents as well as bioassay guided fractionation.

Objectives:

In the present work, the antibacterial properties, especially against methicillin-resistant Staphylococcus aureus (MRSA), of Bromus inermis inflorescence was studied, using the bioassay guided fractionation as well as the bio-autographic method.

Materials and Methods:

The plant organic extract was prepared via maceration in methanol, followed by the fractionation using n-hexane. The extracts were subjected for minimum inhibitory concentrations (MICs) against some human pathogenic bacteria via standard broth micro-dilution assay. Thereafter, a bio-autographical method was applied using the high performance thin layer chromatography (HPTLC) coupled with agar overlay assays for the primary characterization and identification of bioactive substance (s).

Results:

Through the bioassay guided fractionation method, the greatest antibacterial activities were related to the n-hexane extract. It was also revealed that the effective anti-MRSA agent of the assessed plant was a relatively polar substance with an MIC value of about 8 μg/mL against the tested MRSA strain (in comparison with the MIC value of 32 μg/mL for chloramphenicol).

Conclusions:

As a result of the full range UV-Vis scanning of the responsible band in the HPTLC experiments (200-700 nm), the flavonoid was the most imaginable natural compound.

Incidence and outcome of inappropriate in-hospital empiric antibiotics for severe infection: a systematic review and meta-analysis

INTRODUCTION

The aims of this study were to explore the incidence of in-hospital inappropriate empiric antibiotic use in patients with severe infection and to identify its relationship with patient outcomes.

METHODS

Medline (from 2004 to 2014) was systematically searched by using predefined inclusion criteria. Reference lists of retrieved articles were screened for additional relevant studies. The systematic review included original articles reporting a quantitative measure of the association between the use of (in)appropriate empiric antibiotics in patients with severe in-hospital infections and their outcomes. A meta-analysis, using a random-effects model, was conducted to quantify the effect on mortality by using risk ratios.

RESULTS

In total, 27 individual articles fulfilled the inclusion criteria. The percentage of inappropriate empiric antibiotic use ranged from 14.1% to 78.9% (Q1-Q3: 28.1% to 57.8%); 13 of 27 studies (48.1%) described an incidence of 50% or more. A meta-analysis for 30-day mortality and in-hospital mortality showed risk ratios of 0.71 (95% confidence interval 0.62 to 0.82) and 0.67 (95% confidence interval 0.56 to 0.80), respectively. Studies with outcome parameter 28-day and 60-day mortality reported significantly (P ≤0.02) higher mortality rates in patients receiving inappropriate antibiotics. Two studies assessed the total costs, which were significantly higher in both studies (P ≤0.01).

CONCLUSIONS

This systematic review with meta-analysis provides evidence that inappropriate use of empiric antibiotics increases 30-day and in-hospital mortality in patients with a severe infection.

Catheter-Related Polymicrobial Bloodstream Infections among Pediatric Bone Marrow Transplant Outpatients—Atlanta, Georgia, 2007

Objective.

To identify risk factors for polymicrobial bloodstream infections (BSIs) in pediatric bone marrow transplant (BMT) outpatients attending a newly constructed clinic affiliated with a children's hospital.

Methods.

All 30 outpatients treated at a new BMT clinic during September 10-21, 2007, were enrolled in a cohort study. The investigation included interviews, medical records review, observations, and bacterial culture and molecular typing of patient and environmental isolates. Data were analyzed using exact conditional logistic regression.

Results.

Thirteen patients experienced BSIs caused by 16 different, predominantly gram-negative organisms. Presence of a tunneled catheter (odds ratio [OR], 19.9 [95% confidence interval {CI}, 2.4-∞), catheter access (OR, 13.7 [95% CI, 1.8-∞]), and flushing of a catheter with predrawn saline (OR, 12.9 [95% CI, 1.0-766.0]) were independently associated with BSI. The odds of experiencing a BSI increased by a factor of 16.8 with each additional injection of predrawn saline (95% CI, 1.8-827.0). Although no environmental source of pathogens was identified, interviews revealed breaches in recommended infection prevention practice and medication handling. Saline flush solutions were predrawn, and multiple doses were obtained from single-dose preservative-free vials to avoid delays in patient care.

Conclusion.

We speculate that infection prevention challenges in the new clinic, combined with successive needle punctures of vials, facilitated extrinsic contamination and transmission of healthcare-associated pathogens. We recommend that preservative-free single-use vials not be punctured more than once. Use of single-use prefilled saline syringes might prevent multiuse of single-use saline vials. Storage of saline outside a medication supply system might be advisable. Before opening new clinic facilities, hospitals should consider conducting a mock patient flow exercise to identify infection control challenges.

Outcomes of Nosocomial Bloodstream Infections in Adult Neutropenic Patients: A Prospective Cohort and Matched Case-Control Study

Objective:

To examine the clinical and epidemiologic features, excess length of stay, extra costs, and mortality attributable to bloodstream infection (BSI) in neutropenic patients with hematologic malignancies.

Design:

Prospective cohort and matched case-control study.

Patients:

All adult neutropenic patients with hematologic malignancies admitted to Cologne University Hospital between May 1, 1997, and April 30, 1998, were prospectively observed. Case-patients were defined as patients with nosocomial BSI; control-patients were selected among patients without BSI.

Results:

During the study period, the BSI rate in neutropenic patients was 14.3 per 100 neutropenic episodes. Eighty-four case-patients were included. Matching was successful for 96% of the cohort; 81 matched pairs were studied. The mean total length of stay was significantly longer for patients with BSI than for control-patients (37 vs 29 days;P= .002). Extra costs attributable to the infection averaged $3,200 (U.S.) per patient. The crude mortality rates of case-patients and control-patients were 16% and 4%, respectively (P= .013), with an attributable mortality of 12% (odds ratio, 11). Eighty-seven percent of patients met the criteria for sepsis according to the American College of Chest Physicians/Society of Critical Care Medicine. Severe sepsis or septic shock occurred in 13% of patients and was correlated with mortality (55% vs 10% in patients without severe sepsis or septic shock;P=.01).

Conclusions:

Nosocomial BSI in neutropenic patients is significantly associated with an excess length of hospital stay, extra costs, and excess mortality. Severe sepsis and septic shock are closely correlated with an adverse outcome.

Infection Control Programs in Italian Hospitals

Objective:

To quantify the frequency and features of infection control programs implemented in Italian public hospitals.

Methods:

In 2000, a questionnaire was mailed targeting all teaching and research hospitals and those with more than 300 beds, and a random sample of 50% of the district hospitals with fewer than 300 beds.

Results:

The overall response rate was 80%. Fifty percent of the 428 respondent hospitals claimed to have an infection control committee, 43% an infection control physician (average, 1 infection control physician per 2,963 beds), and 33% an infection control nurse (average, I infection control nurse per 572 beds). Having an infection control committee, nurse, and physician occurred significantly more frequently in Northern and Central Italy, where the Regional Authority had implemented a regional infection control policy, and in larger hospitals. Thirty-nine percent of the hospitals claimed to have ongoing surveillance in place, mostly based on laboratory results. Eighty percent of the hospitals had defined at least one written protocol related to infection control policies, mostly for housekeeping, cleaning, disinfecting and sterilizing patient equipment, or standard precautions; on the contrary, policies aimed at preventing specifie infections were less frequent.

Conclusion:

This national representative survey showed that the infrastructure for infection control is suboptimal when compared with the guidelines and surveys published in other countries.

Preventing Central Venous Catheter-Associated Primary Bloodstream Infections: Characteristics of Practices Among Hospitals Participating in the Evaluation of Processes and Indicators in Infection Control (EPIC) Study

Objectives:

To describe the conceptual framework and methodology of the Evaluation of Processes and Indicators in Infection Control (EPIC) study and present results of CVC insertion characteristics and organizational practices for preventing BSIs. The goal of the EPIC study was to evaluate relationships among processes of care, organizational characteristics, and the outcome of BSI.

Design:

This was a multicenter prospective observational study of variation in hospital practices related to preventing CVC-associated BSIs. Process of care information (eg, barrier use during insertions and experience of the inserting practitioner) was collected for a random sample of approximately 5 CVC insertions per month per hospital during November 1998 to December 1999. Organization demographic and practice information (eg, surveillance activities and staff and ICU nurse staffing levels) was also collected.

Setting:

Medical, surgical, or medical-surgical ICUs from 55 hospitals (41 U.S. and 14 international sites).

Participants:

Process information was obtained for 3,320 CVC insertions with an average of 58.2 (± 16.1) insertions per hospital. Fifty-four hospitals provided policy and practice information.

Results:

Staff spent an average of 13 hours per week in study ICU surveillance. Most patients received nontunneled, multiple lumen CVCs, of which fewer than 25% were coated with antimicrobial material. Regarding barriers, most clinicians wore masks (81.5%) and gowns (76.8%); 58.1% used large drapes. Few hospitals (18.1%) used an intravenous team to manage ICU CVCs.

Conclusions:

Substantial variation exists in CVC insertion practice and BSI prevention activities. Understanding which practices have the greatest impact on BSI rates can help hospitals better target improvement interventions.

Electronic Algorithmic Prediction of Central Vascular Catheter Use

Objective.

To develop prediction algorithms for the presence of a central vascular catheter in hospitalized patients with use of data present in an electronic health record. Such algorithms could be used for measurement of device utilization rates and for clinical decision support rules.

Design.

Criterion standard.

Setting.

John H. Stroger, Jr, Hospital of Cook County, a 464-bed public hospital in Chicago, Illinois.

Participants.

Patients admitted to the medical intensive care unit from May 31, 2005 through June 26, 2006 (derivation data set, May 31, 2005-September 28, 2005; validation data set, September 29, 2005-June 28, 2006).

Methods.

Covariates were collected from the electronic medical record for each patient; the outcome variable was presence of a central vascular device. Multivariate models were developed using the derivation set and the generalized estimating equation. Three models, each with increasing database requirements, were validated using the validation set. Device utilization ratios and performance characteristics were calculated.

Results.

Although Charlson score and duration of intensive care unit stay were significant predictors in all models, factors that indicated use or presence of a central line were also important. Device utilization rates derived from the algorithmic models were as accurate as those obtained using manual sampling.

Conclusions.

Automated calculation of central vascular catheter use is both feasible and accurate, providing estimates statistically similar to those obtained using manual surveillance. Prediction modeling of central vascular catheter use may enable automated surveillance of bloodstream infections and enhance important prevention interventions, such as timely removal of unnecessary central lines.

Cost–Benefit Analysis of Chlorhexidine Gluconate Dressing in the Prevention of Catheter-Related Bloodstream Infections

Objectives:

To compare the costs with the benefits of using chlorhexidine gluconate dressings on central venous catheters and to determine the effectiveness of these dressings in reducing local infections and catheter-related bloodstream infections (CRBSIs), costs, and mortality.

Design:

Cost–benefit analysis using randomized, controlled trial data on chlorhexidine dressing prevention of local infection and CRBSI, data on cost of chlorhexidine dressing versus standard treatment, data on averted cost of treating local infection and CRBSI, and data on mortality attributable to CRBSI. Decision analysis evaluated averted CRBSI treatment cost per patient resulting from chlorhexidine dressing use. Sensitivity analyses demonstrated net benefit of chlorhexidine dressing, varying baseline rate of CRBSI, incremental cost of treating CRBSI, and number of catheters, and evaluated mortality preventable through chlorhexidine dressing use, varying baseline rate of CRBSI, number of catheters, and mortality attributable to CRBSI.

Patients and Setting:

Patients of all Philadelphia area hospitals and one Philadelphia academic medical center.

Results:

Estimated potential annual U.S. net benefits from chlorhexidine dressing use ranged from $275 million to approximately $1.97 billion. Cost–benefit findings persisted in sensitivity analyses varying baseline rate of CRBSI, incremental cost of treating CRBSI, and overall number of catheters used. Preventable mortality analyses showed potential decreases of between 329 and 3,906 U.S. deaths annually as a result of nationwide use of chlorhexidine dressing.

Conclusions:

Chlorhexidine dressings would reduce costs, local infections and CRBSIs, and deaths. Use of chlorhexidine dressings should be considered to prevent infections among patients with catheters.

Increasing incidence of hospital-acquired and healthcare-associated bacteremia in northeast Thailand: a multicenter surveillance study

Background

Little is known about the epidemiology of nosocomial bloodstream infections in public hospitals in developing countries. We evaluated trends in incidence of hospital-acquired bacteremia (HAB) and healthcare-associated bacteremia (HCAB) and associated mortality in a developing country using routinely available databases.

Methods

Information from the microbiology and hospital databases of 10 provincial hospitals in northeast Thailand was linked with the national death registry for 2004–2010. Bacteremia was considered hospital-acquired if detected after the first two days of hospital admission, and healthcare-associated if detected within two days of hospital admission with a prior inpatient episode in the preceding 30 days.

Results

A total of 3,424 patients out of 1,069,443 at risk developed HAB and 2,184 out of 119,286 at risk had HCAB. Of these 1,559 (45.5%) and 913 (41.8%) died within 30 days, respectively. Between 2004 and 2010, the incidence rate of HAB increased from 0.6 to 0.8 per 1,000 patient-days at risk (p<0.001), and the cumulative incidence of HCAB increased from 1.2 to 2.0 per 100 readmissions (p<0.001). The most common causes of HAB were Acinetobacter spp. (16.2%), Klebsiella pneumoniae (13.9%), and Staphylococcus aureus (13.9%), while those of HCAB were Escherichia coli (26.3%), S. aureus (14.0%), and K. pneumoniae (9.7%). There was an overall increase over time in the proportions of ESBL-producing E. coli causing HAB and HCAB.

Conclusions

This study demonstrates a high and increasing incidence of HAB and HCAB in provincial hospitals in northeast Thailand, increasing proportions of ESBL-producing isolates, and very high associated mortality.

Increasing resistance rate to carbapenem among blood culture isolates of Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa in a university-affiliated hospital in China, 2004-2011

The objective of this study is to investigate the profile of antimicrobial resistance of Gram-negative bacteria in blood cultures from 2004-2011. Pathogens from positive blood cultures were subcultured, and identified in the First Affiliated Hospital of Nanjing Medical University from January 2004 to December 2011. The antibiotic resistance pattern was analyzed by WHONET 5.4. A total of 1224 cases of Gram-negative bacterial isolates were documented, accounting for 38.6% of the total pathogens isolated from positive blood cultures in the 8-year period. The isolation rates of Klebsiella pneumoniae and Acinetobacter baumannii increased nearly three times over the same time span. Most Gram-negative bacteria isolates, except the isolates of Pseudomonas aeruginosa, showed a significantly increased resistance rate to cephalosporins (in particular third/fourth generation cephalosporins). Noteworthy, the antimicrobial resistance of K. pneumoniae, A. baumannii and P. aeruginosa isolates to carbapenem (imipenem and meropenem) was significantly increased and the resistant rate to carbapenem was >80.0% in A. baumannii in 2011. The results from PCR detection for carbapenemases were as follows: 82.8% (24/29) isolates of K. pneumoniae carried the kpc-2 gene; only three metallo-beta-lactamase-positive P. aeruginosa isolates were detected; and 93.1% (67/72) A. baumannii isolates were blaOXA-23 positive. The antimicrobial resistance rate of Gram-negative bacteria isolated from blood cultures significantly increased from 2004 to 2011, with significant resistance to the third/fourth generation cephalosporins and carbapenem.

The impact of antifungals on toll-like receptors

Fungi are increasingly recognized as major pathogens in immunocompromised individuals. With the increase in the number of fungal infections each year and the development of resistance to current therapy, new approaches to treatment including stimulation of the immune response in addition to concurrent pharmacotherapy is ongoing. The most common invasive fungal infections are caused by Candida spp., Aspergillus spp., and Cryptococcus spp. Amphotericin B (AmB) has remained the cornerstone of therapy against many fulminant fungal infections but its use is limited by its multitude of side effects. Echinocandins are a newer class of antifungal drugs with activity against Candida spp. and Aspergillus spp. and constitutes an alternative to AmB due to superior patient tolerability and fewer side effects. Due to their oral delivery, azoles continue to be heavily used for simple and complex diseases, such as fluconazole for candidal vaginitis and voriconazole for aspergillosis. The objective of this paper is to present current knowledge regarding the multiple interactions between the broad spectrum antifungals and the innate immune response, primarily focusing on the toll-like receptors.

Local versus general anesthesia for transcatheter aortic valve implantation (TAVR)--systematic review and meta-analysis

BACKGROUND

The hypothesis of this study was that local anesthesia with monitored anesthesia care (MAC) is not harmful in comparison to general anesthesia (GA) for patients undergoing Transcatheter Aortic Valve Implantation (TAVR).TAVR is a rapidly spreading treatment option for severe aortic valve stenosis. Traditionally, in most centers, this procedure is done under GA, but more recently procedures with MAC have been reported.

METHODS

This is a systematic review and meta-analysis comparing MAC versus GA in patients undergoing transfemoral TAVR. Trials were identified through a literature search covering publications from 1 January 2005 through 31 January 2013. The main outcomes of interest of this literature meta-analysis were 30-day overall mortality, cardiac-/procedure-related mortality, stroke, myocardial infarction, sepsis, acute kidney injury, procedure time and duration of hospital stay. A random effects model was used to calculate the pooled relative risks (RR) with 95% confidence intervals.

RESULTS

Seven observational studies and a total of 1,542 patients were included in this analysis. None of the studies were randomized. Compared to GA, MAC was associated with a shorter hospital stay (-3.0 days (-5.0 to -1.0); P = 0.004) and a shorter procedure time (MD -36.3 minutes (-58.0 to -15.0 minutes); P <0.001). Overall 30-day mortality was not significantly different between MAC and GA (RR 0.77 (0.38 to 1.56); P = 0.460), also cardiac- and procedure-related mortality was similar between both groups (RR 0.90 (0.34 to 2.39); P = 0.830).

CONCLUSION

These data did not show a significant difference in short-term outcomes for MAC or GA in TAVR. MAC may be associated with reduced procedural time and shorter hospital stay. Now randomized trials are needed for further evaluation of MAC in the setting of TAVR.

Three-year evaluation of nosocomial infection rates of the ICU

BACKGROUND AND OBJECTIVES

Evaluating the incidence of nosocomial and invasive device-related infections enables the comparison of the health care associated infection (HAI) between the intensive care units of different hospitals and different units in the same hospital.

MATERIAL AND METHODS

A retrospective surveillance study was performed to identify nosocomial infections, device-related infections rates, and causal agents from January 2007 through December 2010 in the Anesthesiology Intensive care unit (ICU). HAI were defined according to the CDC (Centers for Disease Control and Prevention) criteria, and invasive device-related infections were defined according to National Nosocomial Infection Surveillance System (NNIS) criteria.

RESULTS

During a two-year period, 939 patients were analyzed throughout a total of 7,892 patient-days. The rates of HAI were 53% in 2007, 29.15% in 2008, 28.85% in 2009 while 16.62% in 2010. Most common HAI was blood stream infection. The rate of soft tissue and skin infection was the second most common. Overall, the most common agents were Gram(-) 56.68%, Gram(+) 31.02% and Candida spp 12.3% among patients with nosocomial infections.

CONCLUSIONS

The incidence of HAI in the ICU of our hospital was high, compared to the Turkish overall rates obtained at the Refik Saydam Center in 2007. When the rates of device-related infections between 2007 and 2008 were compared, they were higher in 2007. The rates of device-related infections were diminished in 2008 to below-national mean rates by infection control measures. Since the rate of urinary catheter-related infections are still high, we should exert continuous efforts for infection control.

Concordance of nasal and diabetic foot ulcer staphylococcal colonization

Nasal carriage of Staphylococcus aureus (SA) is an important risk factor for surgical site infections. The goal of this study was to investigate the concordance between nasal and diabetic foot ulcer (DFU) SA carriage. Seventy-nine subjects with DFUs were assessed for nasal and DFU colonization with SA, including methicillin-resistant SA (MRSA). Twenty-five (31.6%) subjects had nares colonization with SA; 29 (36.7%) had DFU colonization with SA. Seven (8.8%) subjects had nares colonization with MRSA, and 7 (8.8%) had DFU colonization with MRSA. Ulcer duration was associated with MRSA presence (P = 0.01). Sensitivity and specificity of positive nasal SA colonization with positive DFU colonization were 41% and 74%. We found substantial discordance between SA strains colonizing DFU and the nasal cavity. The poor positive predictive values for SA isolation in a DFU based on nasal carriage suggests that SA colonization of a DFU by endogenous SA strains cannot be assumed.

Concomitant infection of the tricuspid valve and right ventricle free wall after chest tube insertion in a young patient without predisposing diseases

Infective endocarditis (IE) is one of the most dreaded complications of healthcare-associated bloodstream infection. It is an important and potentially lethal complication of medical care and there is incidence evidence of it in this population. We describe a case of concomitant infection of the tricuspid valve and right ventricle free wall after chest tube insertion for spontaneous pneumothorax in a young patient without predisposing diseases.

Economic burden of healthcare-associated infection in US acute care hospitals: societal perspective

BACKGROUND

Assessing the costs of healthcare-associated infection (HAI) is challenging. Methodological issues abound. Previous estimates have been derived in diverse ways from varied perspectives in different settings with dissimilar data. RESULTS can be confusing. Full societal costs, which are more inclusive than commonly reported direct hospital costs, have never been fully measured or reported.

OBJECTIVE

To update, combine, and expand previous cost estimates to determine the annual societal burden of illness (direct medical, non-medical, and indirect costs) arising from HAIs in US acute-care hospitals.

METHODS

The research approach encompassed literature and internet searches; reference identification, selection, and review; then data abstraction, compilation, and analyses to estimate full societal costs. Previously published systemic reviews, surveillance reports, and individual clinical studies, along with newly computed component costs, all contributed to final estimates.

RESULTS

HAIs in US acute-care hospitals lead to direct and indirect costs totaling $96-$147 billion annually. These results are subject to the same limitations as previous studies from which contributing data were derived.

CONCLUSION

The enormous clinical and economic burden of infection places HAIs high on the list of devastating and costly illnesses, such as cancer, heart attack, stroke, and diabetes, thereby mandating further research and greater efforts to contain a pressing healthcare problem.

Epidemiology of candidaemia and invasive candidiasis. A changing face

Invasive candidiasis is a leading cause of mortality. Candidaemia is the most common clinical presentation of invasive candidiasis but more that 30% of these infections do not yield positive blood cultures. Candida albicans remains the predominant aetiology, accounting for 50% of all cases. However, there has been an epidemiological shift in the last decades. Some species of Candida different to C. albicans have emerged as an important cause of severe candidaemia as they can exhibit resistance to fluconazole and other antifungal agents. Moreover, there is a different distribution of non C. albicans Candida species in relationship to patients' and hospital characteristics. Thus, Candida parapsilosis has been associated to candidaemia in neonates and young adults. This species usually has an exogenously origin and contaminates medical devices, causing central venous catheter-associated candidaemias. Candida glabrata, Candida tropicalis and Candida krusei are isolated in blood cultures from older patients (>65 years) with important risk factors, such as major abdominal surgery, solid tumours and haematologic malignancies, transplants, and/or prolonged treatment with corticoids. Moreover, important geographical differences in the distribution of the Candida species different to C. albicans causing invasive candidiasis have been reported: C. parapsilosis predominates in Australia, Latin America and Mediterranean countries of Africa, Asia and Europe. In contrast, C. glabrata has an important aetiological role in USA and Central and Northern Europe. Finally, an important and worrying issue is that mortality due to invasive candidiasis remains unacceptably high. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012).

Association between prehospital vitamin D status and hospital-acquired bloodstream infections

BACKGROUND

Alterations in immune function can predispose patients to nosocomial infections. Few studies have explored potentially modifiable host factors that may improve immune function and decrease risk of hospital-acquired bloodstream infection (HABSI). Vitamin D is a key regulator of innate and adaptive immune systems that may influence host susceptibility to infections.

OBJECTIVE

We investigated the association between prehospital serum 25-hydroxyvitamin D [25(OH)D] concentrations and risk of HABSI.

DESIGN

We performed a retrospective cohort study of 2135 adult patients from 2 Boston teaching hospitals. All patients had 25(OH)D concentrations measured before hospitalization between 1993 and 2010. The main outcome measure was HABSI, which was defined as positive blood cultures from samples drawn 48 h after hospital admission. Coagulase-negative Staphylococcus isolates were not considered to be bloodstream infections. Associations between 25(OH)D groups and HABSI were estimated by using bivariable and multivariable logistic regression models. Adjusted ORs were estimated with the inclusion of covariate terms thought to plausibly interact with both 25(OH)D concentration and HABSI.

RESULTS

Compared with patients with 25(OH)D concentrations ≥30 ng/mL, patients with concentrations <30 ng/mL had higher odds of HABSI. For 25(OH)D concentrations <10 ng/mL, the OR was 2.33 (95% CI: 1.45, 3.74); for 25(OH)D concentrations from 10 to 19.9 ng/mL, the OR was 1.60 (95% CI: 1.04, 2.46); and for 25(OH)D concentrations from 20 to 29.9 ng/mL, the OR was 1.13 (95% CI: 0.69, 1.84). After adjustment for age, sex, race (nonwhite compared with white), patient type (medical compared with surgical), and Deyo-Charlson index, the ORs of HABSI were 1.95 (95% CI: 1.22, 3.12), 1.36 (95% CI: 0.89, 2.07), and 0.98 (95% CI: 0.60, 1.62), respectively.

CONCLUSIONS

The analysis of 2135 adult patients showed that 25(OH)D concentrations <10 ng/mL before hospitalization were associated with significantly increased odds of developing HABSI. These data support the initiation of randomized trials to test the role of vitamin D supplementation in HABSI prevention.

Verigene® gram-positive blood culture nucleic acid test

Bloodstream infections (BSIs) are a major cause of morbidity and mortality worldwide, and impose considerable costs on healthcare systems. A key predictor of clinical outcomes in patients with BSIs is the early initiation of appropriate targeted antimicrobial therapy. However, with conventional blood culture methods, the gold standard, there is a significant time delay of approximately 2-3 days before clinical results are available, with many patients receiving inappropriate and/or unnecessary antimicrobial therapy in the interim. During the past two decades, the use of in vitro assays that utilize nucleic acid amplification-based detection of pathogen-associated molecular patterns has led to a significant reduction in the time (hours vs. days with blood culture) to detection and identification of several of the causative pathogens of BSIs and, potentially, earlier initiation of targeted antimicrobial therapy. This review focuses on the properties and clinical use of one of these molecular diagnostic assays, the Verigene(®) Gram-Positive Blood Culture Nucleic Acid Test (BC-GP), which detects many of the potentially pathogenic Gram-positive bacteria associated with BSIs, including Staphylococcus spp., Streptococcus spp., Listeria spp., and Enterococcus spp., and specific resistance markers (mecA, vanA, and vanB). Based on more than 1,600 samples, there was a high degree of agreement between BC-GP test results and those obtained using conventional blood culture and assay methods, irrespective of whether samples were fresh or frozen, and a high degree of agreement for identification of mecA-mediated meticillin resistance in S. aureus and S. epidermidis organisms and vanA- or vanB-mediated vancomycin resistance in E. faecalis and E. faecium organisms.

Clinical diagnostic accuracy of suspected sources of bacteremia and its effect on mortality

BACKGROUND

Although much has been written about bacteremia, evidence of the clinical diagnostic accuracy of bacteremia sources in the absence of microbiological results and the impact of diagnostic accuracy on mortality is scarce.

METHODS

This is a retrospective study of bacteremia episodes over a 2-year period at a general hospital in Madrid. Congruence analyses between clinically presumed and definite sources, acquisition, causative organism, empirical treatment and progression to death were performed.

RESULTS

The study included 323 bacteremia episodes. Clinicians' diagnostic accuracy was higher for gastrointestinal (88.8%; 95% CI: 79%-84%), respiratory (93.9%; 95% CI: 79%-99%) and urinary tract sources (83.6%; 95% CI: 75%-89%) and lower for skin and soft tissues (77.2%; 95% CI: 54%-92%) and, notably, intravascular sources (56%; 95% CI: 39%-71%). Overall, a non-significant (3.45%; 95% CI: -0.6%-13.5%, p=0.47) increase in mortality was observed in the incorrectly suspected bacteremia source group. Mortality related to a definitive source was significantly higher when an intravascular origin was not suspected, resulting in a 26% increase in mortality (95% CI: 1%-52%, p=0.03). Differences in mortality related to inaccurate source assumptions were non-significant when the definitive bacteremia sources were gastrointestinal, urinary, respiratory, skin and soft tissues or unknown. Mortality in the group receiving appropriate empirical antimicrobial treatment was 10.6% compared with 19.7% mortality in the group receiving inappropriate empirical antimicrobial treatment (OR 2; 95% CI: 1.01-4.25).

CONCLUSIONS

The diagnostic accuracy of bacteremia sources is high in all but intravascular sources. A non-suspected intravascular source and inappropriate empirical treatment are related to a higher mortality.

Three-year evaluation of nosocomial infection rates of the ICU

BACKGROUND AND OBJECTIVES

Evaluating the incidence of nosocomial and invasive device-related infections enables the comparison of the health care associated infection (HAI) between the intensive care units of different hospitals and different units in the same hospital.

MATERIAL AND METHODS

A retrospective surveillance study was performed to identify nosocomial infections, device-related infections rates, and causal agents from January 2007 through December 2010 in the Anesthesiology Intensive care unit (ICU). HAI were defined according to the CDC (Centers for Disease Control and Prevention) criteria, and invasive device-related infections were defined according to National Nosocomial Infection Surveillance System (NNIS) criteria.

RESULTS

During a two-year period, 939 patients were analyzed throughout a total of 7,892 patient- days. The rates of HAI were 53% in 2007, 29.15% in 2008, 28.85% in 2009 while 16.62% in 2010. Most common HAI was blood stream infection. The rate of soft tissue and skin infection was the second most common. Overall, the most common agents were Gram(-) 56.68%, Gram(+) 31.02% and Candida spp 12.3% among patients with nosocomial infections.

CONCLUSIONS

The incidence of HAI in the ICU of our hospital was high, compared to the Turkish overall rates obtained at the Refik Saydam Center in 2007. When the rates of device-related infections between 2007 and 2008 were compared, they were higher in 2007. The rates of device- related infections were diminished in 2008 to below-national mean rates by infection control measures. Since the rate of urinary catheter-related infections are still high, we should exert continuous efforts for infection control.

Ex vivo porcine vaginal mucosal model of infection for determining effectiveness and toxicity of antiseptics

AIMS

To develop a semi-high-throughput ex vivo mucosal model for determining efficacy and toxicity of antiseptics.

METHODS AND RESULTS

Explants (5 mm) from freshly excised, porcine vaginal mucosa were infected with methicillin-sensitive Staphylococcus aureus (1 × 10(6)  CFU) at the epithelial surface for 2 h. Haematoxylin and eosin staining revealed healthy uninfected tissue and only minor disruptions in tissue infected with methicillin susceptible Staph. aureus (MSSA), which remained in outer epithelial cell layers. After 2 h infection, 10 μl of chlorhexidine digluconate (CHG, 3%), povidone-iodine (PI, 7·5%), octenidine dihydrochloride (OCT, 0·1%) or polyhexamethylene biguanide (PHMB, 0·1%) was applied. Antiseptics significantly reduced MSSA (1-4 log10  CFU/explants) after 0·25 h to 4 h. CHG, PHMB and OCT exhibited persistence at 24 h. In broth culture, CHG 0·012% and PI 0·625% achieved >6 log10 reductions at 2 h. PI-based formulations were more efficacious than unformulated PI. PI-based formulations exhibited no significant cytotoxicity on explants using an MTT assay.

CONCLUSIONS

All antiseptics tested in the mucosal MSSA infection model reduced MSSA. CHG and PI were more potent in broth culture.

SIGNIFICANCE AND IMPACT OF THE STUDY

We developed a semi-high-throughput mucosal model that can identify compounds or formulations with promising antimicrobial and limited cytotoxic properties.

High-throughput nano-biofilm microarray for antifungal drug discovery

Micro- and nanoscale technologies have radically transformed biological research from genomics to tissue engineering, with the relative exception of microbial cell culture, which is still largely performed in microtiter plates and petri dishes. Here, we present nanoscale culture of the opportunistic fungal pathogen Candida albicans on a microarray platform. The microarray consists of 1,200 individual cultures of 30 nl of C. albicans biofilms (“nano-biofilms”) encapsulated in an inert alginate matrix. We demonstrate that these nano-biofilms are similar to conventional macroscopic biofilms in their morphological, architectural, growth, and phenotypic characteristics. We also demonstrate that the nano-biofilm microarray is a robust and efficient tool for accelerating the drug discovery process: (i) combinatorial screening against a collection of 28 antifungal compounds in the presence of immunosuppressant FK506 (tacrolimus) identified six drugs that showed synergistic antifungal activity, and (ii) screening against the NCI challenge set small-molecule library identified three heretofore-unknown hits. This cell-based microarray platform allows for miniaturization of microbial cell culture and is fully compatible with other high-throughput screening technologies.

Microorganisms are typically still grown in petri dishes, test tubes, and Erlenmeyer flasks in spite of the latest advances in miniaturization that have benefitted other allied research fields, including genomics and proteomics. Culturing microorganisms in small scale can be particularly valuable in cutting down time, cost, and reagent usage. This paper describes the development, characterization, and application of nanoscale culture of an opportunistic fungal pathogen, Candida albicans. Despite a more than 2,000-fold reduction in volume, the growth characteristics and drug response profiles obtained from the nanoscale cultures were comparable to the industry standards. The platform also enabled rapid identification of new drug candidates that were effective against C. albicans biofilms, which are a major cause of mortality in hospital-acquired infections.

Comparative risk of bloodstream infection in hospitalized patients receiving intravenous medication by open, point-of-care, or closed delivery systems

PURPOSE

The impact of i.v. drug delivery via point-of-care (POC)-activated and closed systems versus traditional manual admixture systems on the risk of hospital-acquired bloodstream infection (BSI) is examined.

METHODS

Using data from a proprietary hospital database, a retrospective observational cohort study of patients receiving one or more i.v. drug administrations via POC-activated or closed systems during a three-year period (2007-09) was conducted. Cases of hospital-acquired BSI were identified using diagnosis codes and billing charges for blood cultures and antibiotic use. The risk of BSI in patients with exposure to POC-activated systems, closed systems, or both relative to that of patients exposed to open systems was estimated by odds ratios (ORs) calculated by multivariate logistic regression analysis.

RESULTS

The evaluated data indicated that of the 4,073,864 patients included in the study cohort, 0.5% (n = 20,251) experienced hospital-acquired BSI. After adjusting for selected confounding variables, the use of POC-activated systems was associated with a 16% reduction in BSI risk relative to the use of open systems (OR, 0.84; 95% confidence interval [CI], 0.76-0.93), and the use of closed systems correlated with a 12% risk reduction (OR, 0.88; 95% CI, 0.82-0.96). Patients who received i.v. drugs via both POC-activated and closed systems appeared to derive the greatest relative risk reduction benefit (OR, 0.12; 95% CI, 0.06-0.23).

CONCLUSION

Use of POC-activated and closed systems for i.v. drug delivery was associated with a significantly reduced risk of hospital-acquired BSI compared with exclusive use of open systems in a large population of hospitalized patients.

Microorganisms' colonization and their antibiotic resistance pattern in oro - tracheal tube

BACKGROUND AND OBJECTIVES

Recently, nosocomial infections have been discussed as a critical issue among intubated patients leading to significant morbidity and mortality. Hence, the pattern of microbiological colonization and antibiotic resistance are much valuable in this regard. We aimed to investigate the pattern of microorganism colonization and antibiotic resistance in patients with endotracheal tube or tracheostomy to propose a proper empirical antibiotic therapy in this setting.

MATERIALS AND METHODS

This cross sectional study was conducted among 880 patients admitted in Imam Khomeini hospital between 2008 and 2011 who were subsequently intubated or underwent tracheostomy due to insufficient self ventilation. Samples for microbiological cultures were obtained after extubation and then sent to the central laboratory for further assessment. Antibiograms and microbiological cultures were obtained for each sample.

RESULTS

Of 880 patients enrolled in this study, 531 (60.3%) were male and 349 (39.7%) were female. Nineteen different organisms were isolated including Acinetobacter (213, 24.2%), Pseudomonas aeruginosa (147, 16.7%), Staphylococcus aureus (106, 12%), Proteus mirabilis (90, 10.2%), and other organisms (324, 36.8%). Antibiotic resistance was mainly seen in Acinetobacter (ciprofloxacin, ceftazidim, cefepim, and penicillin), S. aureus (imipenem) and Klebsiella (pipracillintazobactam and ampicillin-sulbactam).

CONCLUSION

This study represents the most common microorganisms colonizing tracheal tube of hospitalized patients and their pattern of antibiotic resistance. Acinetobacter was the most common microorganism isolated from endotracheal tube. Hence, it may be possible to initiate the empiric antibiotic treatment before the results of culture are become available. Ciprofloxacin was also the most prevalent antibiotic revealing resistant pattern. Moreover, most of the microorganisms were sensitive to imipenem and pipracillin-tazobactam.

Feasibility of a novel approach for rapid detection of simulated bloodstream infections via enzymatic template generation and amplification (ETGA)-mediated measurement of microbial DNA Polymerase activity

Bloodstream infections (BSIs) caused by bacteria and fungi are associated with significant morbidity and mortality. Currently, blood culture is the gold standard for confirming a suspected BSI, but has the drawback of lengthy time-to-detection (TTD) required for indicating the presence of microbes. Detection of conserved microbial nucleic acid sequences within blood culture samples via PCR has been demonstrated to offer potential for reducing the TTD of BSI; however, these approaches have various other limitations. We report a novel approach toward rapid detection of microbes from simulated BSI via differential hematopoietic cell lysis followed by enzymatic template generation and amplification (ETGA)-mediated measurement of microbial DNA polymerase extension activity. The differential cell lysis procedure effectively reduced the level of detectable DNA polymerase extension activity associated with human-derived hematopoietic cells present in blood culture samples taken from healthy donors. After treatment with the differential cell lysis procedure, the ETGA assay detected a panel of clinically prevalent bacteria and Candida albicans from spiked blood culture samples. The ETGA blood culture method also reduced by threefold the TTD required for simulated BSI, compared with a continuous-monitoring blood culture instrument. In summary, these findings demonstrate the feasibility of an innovative approach toward a rapid, sensitive, and universal screen for microbes within blood culture samples. Potential for clinical application and automation are also addressed.

Overall burden of bloodstream infection and nosocomial bloodstream infection in North America and Europe

In this systematic review, we estimated the total number of episodes of bloodstream infection (BSI) and deaths from BSI per year in North America and Europe, using data from population-based settings. Then, we estimated the number of episodes and deaths from nosocomial BSI from population-based studies and nosocomial infection surveillance systems. We estimated 575 000-677 000 episodes of BSI per year in North America (536 000-628 000 in the USA and 40 000-49 000 in Canada) and 79 000-94 000 deaths (72 000-85 000 in the USA and 7000-9000 in Canada), using estimates from three population-based studies. We estimated over 1 200 000 episodes of BSI and 157 000 deaths per year in Europe, using estimates from one population-based study in each of the following countries: Denmark (9100 episodes and 1900 deaths), Finland (8700 episodes and 1100 deaths) and England (96 000 episodes and 12 000-19 000 deaths). There were substantial differences in estimates of nosocomial BSI between population-based and nosocomial infection surveillance data. BSI has a major impact on the morbidity and mortality of the general population, as it ranks among the top seven causes of death in all included countries in North America and Europe. However, it is difficult to obtain precise estimates of nosocomial BSI, owing to the limited number of studies. This review highlights the need for a greater focus on BSI research in order to reduce the overall burden of disease by improving the outcome of patients with BSI. It also emphasizes the role of infection control and prevention methods in reducing the burden of nosocomial BSI.

Reducing mortality related to adverse events in children

Since the launch of the 100,000 Lives Campaign by the Institute for Healthcare Improvement (IHI), preventing medical adverse events to reduce avoidable mortality has emerged as a central focus for health care providers, institutions, regulators, insurance companies, and patients. Evidence-based interventions targeting the 6 interventions in the campaign have been associated with a reduction in preventable hospital deaths in the United States. The generalizability of the IHI's campaign to the pediatric population is only partly applicable. Pediatric experiences with rapid response teams and preventing central-line infections parallel the published experience of adults, with promise to significantly reduce preventable pediatric mortality.

The ability of virulence factor expression by Pseudomonas aeruginosa to predict clinical disease in hospitalized patients

BACKGROUND

Pseudomonas aeruginosa is an opportunistic pathogen that frequently causes hospital acquired colonization and infection. Accurate identification of host and bacterial factors associated with infection could aid treatment decisions for patients with P. aeruginosa cultured from clinical sites.

METHODS

We identified a prospective cohort of 248 hospitalized patients with positive P. aeruginosa cultures. Clinical data were analyzed to determine whether an individual met predefined criteria for infection versus colonization. P. aeruginosa isolates were tested for the expression of multiple phenotypes previously associated with virulence in animal models and humans. Logistic regression models were constructed to determine the degree of association between host and bacterial factors with P. aeruginosa infection of the bloodstream, lung, soft tissue and urinary tract.

RESULTS

One host factor (i.e. diabetes mellitus), and one bacterial factor, a Type 3 secretion system positive phenotype, were significantly associated with P. aeruginosa infection in our cohort. Subgroup analysis of patients with P. aeruginosa isolated from the urinary tract revealed that the presence of a urinary tract catheter or stent was an additional factor for P. aeruginosa infection.

CONCLUSIONS

Among hospitalized patients with culture-documented P. aeruginosa, infection is more likely to be present in those with diabetes mellitus and those harboring a Type 3 secretion positive bacterial strain.

Virulence gene profiling and molecular characterization of hospital-acquired Staphylococcus aureus isolates associated with bloodstream infection

A better understanding of virulence gene profiling and molecular characterization of Staphylococcus aureus isolates associated with bloodstream infection (BSI) may provide further insights related to clinical outcomes with these infections. We analyzed 89 S. aureus isolates including 37 MRSA isolates (41.6%) recovered from 89 adult patients with BSI from 4 hospitals in Zhejiang province, eastern China. Thirty-five (94.6%) of MRSA isolates and 4 (7.7%) of methicillin-sensitive S. aureus (MSSA) isolates were resistant to multiple antimicrobials. All isolates harbored at least 2 of 22 possible virulence genes, including sdrC (92.1%), icaA (89.9%), hla (80.9%), clf (69.7%), sea (68.5%), sdrD (67.4%), hlb (67.4%), sdrE (65.2%), sei (51.7%), seg (50.6%), and cna (50.6%). Forty-four (49.4%) of all S. aureus BSI isolates, including 23 (62.2%) of MRSA isolates, harbored ≥10 of the virulence genes evaluated in this study. Sixteen (43.2%) MRSA isolates and 5 (9.6%) MSSA isolates harbored the gene encoding Panton-Valentine leukocidin (PVL). Collective genes for pvl, sdrE, sed, seg, and sei among MRSA isolates were significantly more frequent relative to MSSA isolates (P < 0.05). A total of 22 sequence types (STs), including novel ST2184, ST2199, and ST2200, and 33 spa types, including novel spa types t9530 and t9532, were identified among S. aureus BSI isolates, among which ST188 (15.7%) and ST7 (15.7%), and t091 (12.4%) and t189 (12.4%), seldom noted for Chinese isolates previously, were major STs and spa types, respectively. In contrast to previous reports, no predominant clones were found in the present study. Among the MRSA isolates, although ST239-MRSA-SCCmecIII, predominant clone in China, still represented the most common clone, it only accounted for 18.9%. However, ST188-MRSA- SCCmecIV seldom reported before accounted for 10.8%. Among the MSSA isolates, ST7-MSSA represented the most common clone (23.1%), followed by ST188-MSSA and ST630-MSSA (9.6% each). In conclusion, simultaneous carriage of multiple virulence genes and genetically considerable diversity were common among S. aureus BSI isolates. Furthermore, MRSA isolates exhibited more frequent carriage of superantigen genes and pvl relative to MSSA isolates. Taken together, there are distinctive virulence gene profiling and molecular characteristic among S. aureus isolates associated with bloodstream infection in China.

The morbidity and mortality of patients with fungal infections before and during extracorporeal membrane oxygenation support

OBJECTIVE

To evaluate the prevalence of fungal infections (both pre-cannulation and post-cannulation) while on extracorporeal membrane oxygenation support and the associated morbidity and mortality.

DESIGN

Retrospective cohort study.

PATIENT AND METHODS

The Extracorporeal Life Support Organization database is an international voluntary registry of clinical data for patients placed on extracorporeal membrane oxygenation. The database was queried for all patients on extracorporeal membrane oxygenation from 1997 to 2009. Patient and extracorporeal membrane oxygenation data collected included age, support type, length of support, infection status and organism code, discharge status, complications, and component failures. Outcomes of interest were mortality, extracorporeal membrane oxygenation-related patient complications, and mechanical component failures.

RESULTS

From 1997 to 2009, there were 21,073 patients' extracorporeal membrane oxygenation runs analyzed of which 12,933 were in the neonatal group (0-30 days), 6,073 were in the pediatric group (31 days to <18 yrs old), and 2,067 were in the adult group (≥18 yrs). The prevalence of fungal infection during extracorporeal membrane oxygenation varied by age group and timing of infection and ranged from 0.04% to 5%. Fungal infections pre-extracorporeal membrane oxygenation and on-extracorporeal membrane oxygenation conferred a statistically significant higher relative risk of mortality for all age groups and varied by support type and timing of infection. Extracorporeal membrane oxygenation-related complications and component failures were not statistically significantly affected by infection status.

CONCLUSIONS

Fungal infection before or during extracorporeal membrane oxygenation increases the odds of mortality and the magnitude of this effect is dependent upon age-group and timing of infection. This increased mortality was not the result of increased patient or mechanical complications during extracorporeal membrane oxygenation. For patients with fungal infections pre-extracorporeal membrane oxygenation, 82%-89% demonstrated presumed clearance during extracorporeal membrane oxygenation. Although the risk of mortality increased with fungal infections, it does not appear that fungal infection before or during extracorporeal membrane oxygenation is a contraindication to initiation or continuation of support.

Antimicrobial activity of wild mushroom extracts against clinical isolates resistant to different antibiotics

AIMS

This work aimed to screen the antimicrobial activity of aqueous methanolic extracts of 13 mushroom species, collected in Bragança, against several clinical isolates obtained in Hospital Center of Trás-os-Montes and Alto Douro, Portugal.

METHODS AND RESULTS

Microdilution method was used to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). MIC results showed that Russula delica and Fistulina hepatica extracts inhibited the growth of gram-negative (Escherichia coli, Morganella morganni and Pasteurella multocida) and gram-positive (Staphylococcus aureus, MRSA, Enterococcus faecalis, Listeria monocytogenes, Streptococcus agalactiae and Streptococcus pyogenes) bacteria. A bactericide effect of both extracts was observed in Past. multocida, Strep. agalactiae and Strep. pyogenes with MBC of 20, 10 and 5 mg ml⁻¹, respectively. Lepista nuda extract exhibited a bactericide effect upon Past. multocida at 5 mg ml⁻¹ and inhibited Proteus mirabilis at 20 mg ml⁻¹. Ramaria botrytis extract showed activity against Enterococcus faecalis and L. monocytogenes, being bactericide for Past. multocida, Strep. agalactiae (MBCs 20 mg ml⁻¹) and Strep. pyogenes (MBC 10 mg ml⁻¹). Leucopaxillus giganteus extract inhibited the growth of E. coli and Pr. mirabilis, being bactericide for Past. multocida, Strep. pyogenes and Strep. agalactiae.

CONCLUSIONS

Fistulina hepatica, R. botrytis and R. delica are the most promising species as antimicrobial agents.

SIGNIFICANCE AND IMPACT OF THE STUDY

Mushroom extracts could be an alternative as antimicrobials against pathogenic micro-organisms resistant to conventional treatments.

Differential time to positivity of blood cultures: a valid method for diagnosing catheter-related bloodstream infections in the intensive care unit

PURPOSE

The validation in critical patients with short-term catheters of a method for diagnosing catheter-related bloodstream infection (CR-BSI), based on the differential time to positivity (DTP) of blood cultures.

METHODS

Patients suspected of having CR-BSI were included. Two peripheral vein blood cultures and a catheter hub blood culture were simultaneously carried out. The responsible catheter was removed and tip cultured. Times to positivity of all blood cultures were automatically registered. CR-BSI was diagnosed when all the cultures were positive for the same microorganism and DTP≥120 min. This diagnosis was compared with the one obtained using the standard method.

RESULTS

226 cases suspected of CR-BSI were analyzed during a 20-month period. A total of 19 removed catheters were associated with CR-BSI. Seven cases of polymicrobial cultures (4 with CR-BSI) were discarded from the final analysis due to the impossibility of determining the time to positivity for each individual microorganism. Using the DTP method, 12 out of 15 CR-BSI cases were diagnosed (sensitivity 80%, specificity 99%, PPV 92%, NPV 98%). In a ROC curve, we found a cut-off value of 17.7 h in positivity of hub blood cultures that may be useful for diagnosing CR-BSI.

CONCLUSION

DTP can be a valid method for CR-BSI diagnosis in critically ill patients, avoiding unnecessary catheter withdrawal.

Bloodstream Bacterial Pathogens and their Antibiotic Resistance Pattern in Dhahira Region, Oman

OBJECTIVES

To describe the epidemiological, clinical, microbiological characteristics and antimicrobial resistance pattern of Bloodstream infections in Dhahira region, Oman.

METHODS

Clinical data was collected from all patients with positive blood cultures for two years period. Standard laboratory methods were used for blood culture. Antibiotic sensitivity was tested using Kirby-Bauer disc diffusion method.

RESULTS

Of the 360 bacterial pathogens isolated from 348 patients, 57.8% were gram-positive and 42.2% were gram-negative. The common isolates were: Streptococcus species 76 (21.1%), coagulase-negative Staphylococci 75 (20.8%), Escherichia coli 43 (11.9%), Staphylococcus aureus 41 (11.4%). Overall, mortality was 21.3% (74/348). Staphylococcus species (Staphylococcus aureus and CoNS) were more commonly resistant to Trimethoprim/ Sulphamethoxazole (35.3%) and Penicillin (25.9%). Streptococcus species were resistant to Trimethoprim/Sulphamethoxazole (39.1%) and Erythromycin (19.6%).

CONCLUSION

Bloodstream infections are important causes of morbidity and mortality in our patients, especially among chronically ill elderly adult males. Prescription of proven resistant antibiotics to suspected bacteremic patients needs attention in Dhahira region.

Reducing bloodstream infections in pediatric rehabilitation patients receiving parenteral nutrition

OBJECTIVE

To report our quality improvement efforts to reduce total parenteral nutrition (TPN)-associated bloodstream infections, and the results of those efforts, during the period including the first quarter of 2004 through the third quarter of 2010.

METHODS

A variant on failure modes and effect analysis and existing guidelines were used to develop and modify interventions. Effectiveness of the interventions was assessed by using a graphical depiction of interrupted time-series data on TPN-associated infections per 1000 TPN-days, aggregated across quarters within intervention periods.

RESULTS

Although initial interventions yielded limited reductions in infection rates, it was not until the implementation of a multifaceted "maintenance intervention bundle" that rates strongly responded. After this key intervention revision, the TPN-associated infection rate decreased between implementation in the first quarter of 2008 from 26.1 to 4.8 per 1000 TPN-days during the 8 quarters aggregated comprising the first quarter of 2008 through the fourth quarter of 2009. The final addition of an alcohol-swab cap resulted in a reduction of rates to 0 for the first three-quarters of 2010.

CONCLUSIONS

Our evidence suggests that iterative design/redesign of interventions using failure modes and effect analysis has directly reduced TPN-associated bloodstream infections.

Nutrition therapy cost analysis in the US: pre-mixed multi-chamber bag vs compounded parenteral nutrition

BACKGROUND

Bloodstream infections (BSI) occur in up to 350 000 inpatient admissions each year in the US, with BSI rates among patients receiving parenteral nutrition (PN) varying from 1.3% to 39%. BSI-attributable costs were estimated to approximate $US12 000 per episode in 2000. While previous studies have compared the cost of different PN preparation methods, this analysis evaluates both the direct costs of PN and the treatment costs for BSI associated with different PN delivery methods to determine whether compounded or manufactured pre-mixed PN has lower overall costs.

OBJECTIVE

The purpose of this study was to compare costs in the US associated with compounded PN versus pre-mixed multi-chamber bag (MCB) PN based on underlying infection risk.

METHODS

Using claims information from the Premier Perspective™ database, multivariate logistic regression was used to estimate the risk of infection. A total of 44 358 hospitalized patients aged ≥18 years who received PN between 1 January 2005 and 31 December 2007 were included in the analyses. A total of 3256 patients received MCB PN and 41 102 received compounded PN. The PN-associated costs and length of stay were analysed using multivariate ordinary least squares regression models constructed to measure the impact of infectious events on total hospital costs after controlling for baseline and clinical patient characteristics.

RESULTS

There were 7.3 additional hospital days attributable to BSI. After adjustment for baseline variables, the probability of developing a BSI was 30% higher in patients receiving compounded PN than in those receiving MCB PN (16.1% vs 11.3%; odds ratio = 1.56; 95% CI 1.37, 1.79; p < 0.0001), demonstrating 2172 potentially avoidable infections. The observed daily mean PN acquisition cost for patients receiving MCB PN was $US164 (including all additives and fees) compared with $US239 for patients receiving compounded PN (all differences p < 0.001). With a mean cost attributable to BSI of $US16 141, the total per-patient savings (including avoided BSI and PN costs) was $US1545.

CONCLUSION

In this analysis of real-world PN use, MCB PN is associated with lower costs than compounded PN with regards to both PN acquisition and potential avoidance of BSI. Our base case indicates that $US1545 per PN patient may be saved; even if as few as 50% of PN patients are candidates for standardized pre-mix formulations, a potential savings of $US773 per patient may be realized.