Nosocomial bloodstream infections. Secular trends in rates, mortality, and contribution to total hospital deaths

Novel dalbavancin-PLLA implant coating prevents hematogenous Staphylococcus aureus infection in a minimally invasive mouse tail vein model

Infective/bacterial endocarditis is a rare but life-threatening disease with a hospital mortality rate of 22.7% and a 1-year mortality rate of 40%. Therefore, continued research efforts to develop efficient anti-infective implant materials are of the utmost importance. Equally important is the development of test systems that allow the performance of new materials to be comprehensively evaluated. In this study, a novel antibacterial coating based on dalbavancin was tested in comparison to rifampicin/minocycline, and the suitability of a recently developed mouse tail vein model for testing the implant coatings was validated. Small polymeric stent grafts coated with a poly-L-lactic acid (PLLA) layer and incorporated antibiotics were colonized with Staphylococcus (S.) aureus before implantation into the tail vein of mice. The main assessment criteria were the hematogenous spread of the bacteria and the local tissue reaction to the contaminated implant. For this purpose, colony-forming units (CFU) in the blood, spleen and kidneys were determined. Tail cross sections were prepared for histological analysis, and plasma cytokine levels and expression values of inflammation-associated genes were examined. Both antibiotic coatings performed excellently, preventing the onset of infection. The present study expands the range of available methods for testing the anti-infectivity of cardiovascular implants, and the spectrum of agents for effective surface coating.

Catheter-Related Bloodstream Infection With Femoral Central Access Versus Internal Jugular Access in Patients Admitting to Medical Intensive Care Unit

Background

The current research focused on studying the pattern of catheter-related bloodstream infections (CRBSI) with femoral central access versus internal jugular access in patients admitted to the medical intensive care unit (ICU).

Methods

A cross-sectional study was conducted at the Department of Emergency Medicine, Shifa International Hospital, between March 4, 2022, and August 4, 2022. All individuals who presented to the ICU who needed a central venous catheter (CVC) for more than 48 hours were included. Catheter insertion was not permitted if the patient had a history of dermatitis or burns at the site of insertion or if the hemodialysis procedure necessitated the insertion of the catheter into a blood vessel. Three groups of patients were created: group A patients had been diagnosed with CRBSI; group B patients had catheter colonization (CC); and group C did not have CRBSI or CC. Standard microbiological methods were used to identify all of the bacteria collected from the cultures. All data was documented in a predefined pro forma.

Results

Overall, 20 (12.12%) patients had positive CRBSI, 68 (41.5%) had CC, and the remaining 46.3% of cultures were negative. Elderly populations were more prone to acquiring CRBSI showing a significant correlation between older age and CRBSI (p < 0.0001). CC was significantly associated with a longer duration of ICU stay, i.e., 30.3 ± 3.7 (p = 0.003). The absence of both CRBSI and CC was significantly associated with a lower duration of catheterization (11 ± 8.5 days in group C versus 22.1 ± 6.9 and 18.7 ± 7 days in groups A and B, respectively; p < 0.0001). Our study revealed a higher risk of CRBSI when the femoral access was compared to the internal jugular access (58.3% vs. 41.7%; p = 0.0008). The study did not find any significant association of CC with femoral or internal jugular access. Furthermore, a significantly higher rate of negative cultures was reported in patients with internal jugular access as compared to femoral vein access (85.8% vs. 14.2%; p = 0.007).

Conclusion

The need for routinely monitoring and observing the microbiological spectrum in patients receiving care in intensive care units is highlighted by the current investigation. The patients with internal jugular vein access had a decreased incidence of CRBSI and CC, while those with femoral access experienced CRBSI more frequently. Escherichia coli and Pseudomonas aeruginosa were the most frequently isolated germs, and both were resistant to various drugs that are used today. It is essential to regularly monitor the epidemiology of CRBSI in order to adopt preventative measures for infection prevention and control, such as staff education, strict hygiene standards, and a higher nurse-to-patient ratio.

The Global, Regional, and National Burden and Trends of Infective Endocarditis From 1990 to 2019: Results From the Global Burden of Disease Study 2019

Introduction

Infective endocarditis (IE) presents with increasing incidence and mortality in some regions and countries, as well as serious socioeconomic burden. The current study aims to compare and interpret the IE burden and temporal trends globally and in different regions from 1990 to 2019.

Methods

Data on the incidence, deaths and disability-adjusted life years (DALYs) caused by IE were extracted and analyzed from the Global Burden of Disease Study 2019. Estimated annual percentage changes (EAPC) were adopted to quantify the change trends of age-standardized rates (ASRs). Besides, potential contributors of serious IE burden were also evaluated including age, gender, social-demographic index (SDI), and age-standardized incident rate (ASIR) in 1990.

Results

Globally, the number of IE cases and deaths has increased sharply during the past 30 years from 478,000 in 1990 to 1,090,530 in 2019 and from 28,750 in 1990 to 66,320 in 2019, and both presented an upward temporal trend annually (EAPC:1.2 for incidence and 0.71 for death). However, the EAPC of age-standardized DALYs demonstrated a negative temporal trend despite increasing DALYs from 1,118,120 in 1990 to 1,723,590 in 2019. Moreover, older patients and men were more severely affected. Meanwhile, different SDI regions had different disease burdens, and correlation analyses indicated that SDI presented a positive association with ASIR (R = 0.58, P < 0.0001), no association with age-standardized death rate (R = −0.06, P = 0.10), and a negative association with age-standardized DALYs (R = −0.40, P < 0.0001). In addition, the incidence of IE increased in most countries during the past 30 years (190 out of 204 countries). However, the change trends of deaths and DALYs were heterogeneous across regions and countries. Finally, we discovered positive associations of the EAPC of ASRs with the SDI in 2019 among 204 countries and territories but few associations with the ASIR in 1990.

Conclusion

Generally, the global burden of IE is increasing, and there is substantial heterogeneity in different genders, ages and regions, which may help policy-makers and medical staff respond to IE and formulate cost-effective interventional measures.

Temporal Trends in the Microbiological Characteristics of Sepsis in the United States: A Population Based Study

BACKGROUND

Epidemiologic studies are needed for monitoring population-level trends in sepsis. This study examines sepsis-causing microorganisms from 2006 to 2014 in the United States using data from the Nationwide Inpatient Sample database.

METHODS

7 860 686 adults hospitalized with sepsis were identified using a validated ICD-9 coding approach. Associated microorganisms were identified by ICD-9 code and classified by major groups (Gram-positive, Gram-negative, fungi, anaerobes) and specific species for analysis of their incidence and mortality.

RESULTS

The rate of sepsis incidence has increased for all four major categories of pathogens, while the mortality rate decreased. In 2014, Gram-negative pathogens had a higher incidence than Gram-positives. Anaerobes increased the fastest with an average annual increase of 20.17% (p < 0.001). Fungi had the highest mortality (19.28%) and the slowest annual decrease of mortality (-2.31%, p = 0.006) in 2013, while anaerobic sepsis had the highest hazard of mortality (adjusted HR 1.60, 95% CI 1.53-1.66).

CONCLUSIONS

Gram-negative pathogens have replaced Gram-positives as the leading cause of sepsis in the United States in 2014 during the study period (2006-2014). The incidence of anaerobic sepsis has an annual increase of 20%, while the mortality of fungal sepsis has not decreased at the same rate as other microorganisms. These findings should inform the diagnosis and management of septic patients, as well as the implementation of public health programs.

Characteristics of infective endocarditis in a cancer population

Background

Infective endocarditis (IE) is more common in patients with cancer as compared with the general population. Due to an immunocompromised state, the need for invasive procedures, hypercoagulability and the presence of indwelling catheters, patients with cancer are particularly predisposed to the development of IE.

Objectives

Limited information exists about IE in patients with cancer. We aimed to evaluate the characteristics of patients with cancer and IE at our tertiary care centre, including a comparison of the microorganisms implicated and their association with mortality.

Methods

A retrospective chart review of patients with cancer who had echocardiography for suspicion of endocarditis was conducted. A total of 56 patients with a confirmed diagnosis of cancer and endocarditis, based on the modified Duke criteria, were included in the study. Baseline demographics, risk factors for developing IE, echocardiography findings, microbiology and mortality data were analysed.

Results

Following the findings of vegetations by echocardiography, the median survival time was 8.5 months. Staphylococcus aureus was the most common organism identified as causing endocarditis. The mitral and aortic valves were the most commonly involved sites of endocarditis. Patients with S. aureus endocarditis (SAE) had a significantly poorer survival when compared with patients without SAE (p=0.0217) over the 12-month period from diagnosis of endocarditis.

Conclusions

Overall survival of patients with cancer and endocarditis is poor, with a worse outcome in patients with SAE.

Stenotrophomonas maltophilia bacteremia in children: risk factors and mortality rate

Purpose

Stenotrophomonas maltophilia (S. maltophilia) is an opportunistic and nosocomial pathogen that can cause an invasive and fatal infection, particularly in hospitalized and immunocompromised patients. However, little is known about the impact of S. maltophilia bacteremia in pediatric patients. Therefore, we aimed to identify risk factors for mortality, antibiotics susceptibility to S. maltophilia, and mortality rates in pediatric patients with S. maltophilia bacteremia.

Methods

We conducted a retrospective cohort study by identifying all S. maltophilia positive blood cultures in the microbiology laboratory database between January 2007 and December 2018 from hospitalized pediatric patients (age 1–14 years). After identifying patients with S. maltophilia bacteremia, medical charts were reviewed for demographics, clinical data, and outcomes within seven days of bacteremia diagnosis. Risk factors associated with mortality in S. maltophilia bacteremia patients were determined using univariate and multivariate analyses.

Findings

Sixty-eight pediatric patients with S. maltophilia bacteremia were identified. All infections were nosocomial infections, and (88.2%) bacteremia cases were catheter-related bloodstream infections. On multivariate analysis, ICU admission prior to bacteremia episode and neutropenia were the major risk factors associated with mortality. S. maltophilia was the most susceptible to trimethoprim and sulfamethoxazole (TMP/SMX, 94.1%), followed by levofloxacin (85.7%). The overall mortality rate within seven days of S. maltophilia bacteremia diagnosis was 33.8%.

Conclusion

S. maltophilia bacteremia is a devastating emerging infection associated with high mortality among hospitalized children. Therefore, early diagnosis and prompt management based on local susceptibility data are crucial. Various risk factors, especially ICU admission prior to bacteremia episode and neutropenia, are associated with S. maltophilia bacteremia mortality.

Genomic analyses of Staphylococcus aureus clonal complex 45 isolates does not distinguish nasal carriage from bacteraemia

Staphylococcus aureus is a colonizing opportunistic pathogen and a leading cause of bloodstream infection with high morbidity and mortality. S. aureus carriage frequency is reportedly between 20 and 40 % among healthy adults, with S. aureus colonization considered to be a risk factor for S. aureus bacteraemia. It is unknown whether a genetic component of the bacterium is associated with S. aureus bacteraemia in comparison to nasal carriage strains. Previous association studies primarily focusing on the clinical outcome of an S. aureus infection have produced conflicting results, often limited by study design challenged by sample collections and the clonal diversity of S. aureus. To date, no study has investigated whether genomic features separate nasal carriage isolates from S. aureus bacteraemia isolates within a single clonal lineage. Here we have investigated whether genomic features, including single-nucleotide polymorphisms (SNPs), genes, or kmers, distinguish S. aureus nasal carriage isolates from bacteraemia isolates that all belong to the same clonal lineage [clonal complex 45 (CC45)] using whole-genome sequencing (WGS) and a genome-wide association (GWA) approach. From CC45, 100 isolates (50 bacteraemia and 50 nasal carriage, geographically and temporally matched) from Denmark were whole-genome sequenced and subjected to GWA analyses involving gene copy number variation, SNPs, gene content, kmers and gene combinations, while correcting for lineage effects. No statistically significant association involving SNPs, specific genes, gene variants, gene copy number variation, or a combination of genes was identified that could distinguish bacteraemia isolates from nasal carriage isolates. The presented results suggest that all S. aureus nasal CC45 isolates carry the potential to cause invasive disease, as no core or accessory genome content or variations were statistically associated with invasiveness.

Incidence of coagulase-negative staphylococcal bacteremia among ICU patients: decontamination studies as a natural experiment

The epidemiology of coagulase-negative staphylococcal (CNS) bacteremia among adult ICU patients remains unclear. Decontamination studies among ICU patients provide a unique opportunity to study the impacts of different diagnostic criteria, exposure to various decontamination interventions, and various other factors, on its incidence over three decades. Decontamination studies among ICU patients reporting CNS bacteremia incidence data were obtained mostly from recent systematic reviews. The CNS bacteremia incidence within component (control and intervention) groups of decontamination studies was benchmarked versus studies without intervention (observational groups). The impacts of antibiotic versus chlorhexidine decontamination interventions, control group concurrency, publication year, and diagnostic criteria were examined in meta-regression models. Among non-intervention (observational) studies which did versus did not specify stringent (≥ 2 positive blood cultures) diagnostic criteria, the mean CNS bacteremia incidence per 100 patients (and 95% CI; n) is 1.3 (0.9–2.0; n = 23) versus 3.6 (1.8–6.9; n = 8), respectively, giving an overall benchmark of 1.8 (1.2–2.4; n = 31). Versus the benchmark incidence, the mean incidence is high among concurrent control (5.7; 3.6–9.1%) and intervention (5.2; 3.6–6.9%), but not non-concurrent control (1.0; 0.4–3.9%) groups of 21 antibiotic studies, nor among eleven component groups of chlorhexidine studies. This high incidence remained apparent (p < 0.01) in meta-regression models adjusting for group wide factors such as diagnostic criteria and publication year. The incidence of CNS bacteremia within both intervention and concurrent (but not non-concurrent) control groups of antibiotic-based decontamination studies are unusually high even accounting for variable diagnostic criteria and other factors.

Incidence of and associated factors for bacterial colonization of intravenous catheters removed from dogs in response to clinical complications

BACKGROUND

Infection rate associated with intravenous (IV) catheter placement is emerging as an important issue in small animal veterinary medicine, mostly because of the economic costs associated with these infections. Identification of possible associated factors may provide useful information for the surveillance and prevention of such infections.

OBJECTIVES

To determine the incidence of positive bacterial cultures obtained from IV catheters used in dogs hospitalized for at least 48 hours and removed because of clinical complication. To identify the bacteria involved and factors associated with bacterial colonization.

ANIMALS

One-hundred eighty-two dogs that underwent IV catheterization from January 2015 to July 2015 at the Veterinary Teaching Hospital of Alfonso X el Sabio University of Madrid were enrolled in the study.

RESULTS

The bacterial colonization rate of all IV catheters removed in response to clinical complications was 39.6%, the cumulative proportion of catheters that remained in place at 24, 48, and 72 hours after placement was 89.5, 78, and 59.4%, respectively. Multivariable Cox proportional hazards regression indicated significant associations for staff who performed catheterization (junior, P = .002; student, P = .034) and use of steroidal anti-inflammatory drugs (P = .036). The most frequently isolated bacterium was Acinetobacter spp. (21.7%).

CONCLUSIONS AND CLINICAL IMPORTANCE

The bacterial colonization incidence related to IV catheter placement was slightly higher than the incidence described in other veterinary studies. Associated factors not previously described in veterinary medicine were found. The most frequently isolated organism was Acinetobacter spp., indicating its importance as an emerging pathogen in catheter colonization.

Opciones terapéuticas frente a especies de Candida resistentes a las equinocandinas

<p><strong>Introducción</strong>: La infección por levaduras del género <em>Candida</em> representa la causa más común de infecciones fúngicas invasivas. Su alta incidencia y la creciente resistencia frente a los azoles y, recientemente, a las equinocandinas ha generado la necesidad de buscar nuevas alternativas farmacológicas. Esta revisión presenta las principales alternativas farmacológicas en estudio frente a <em>Candida</em> resistente a equinocandinas. <strong>Métodos</strong>: Se buscó literatura referente al tema en las bases de datos Bireme, Clinical Key, Embase, Cochrane, Lilacs, Pubmed y Scopus. Se incluyeron 15 artículos en esta revisión. <strong>Resultados</strong>: Se exploran diferentes alternativas, incluyendo el aumento de dosis de las equinocandinas, su combinación con otros medicamentos y nuevos compuestos en estudio. <strong>Conclusión</strong>: A pesar de que las infecciones por <em>Candida</em> resistente a equinocandinas aún representan un desafío, dos alternativas farmacológicas se presentan como promisorias: la combinación con medicamentos existentes como el diclofenaco y nuevos compuestos que se encuentran actualmente en fase II de estudios clínicos.</p><p> </p>

Clinical value of procalcitonin for suspected nosocomial bloodstream infection

BACKGROUND/AIMS

Procalcitonin (PCT) may prove to be a useful marker to exclude or predict bloodstream infection (BSI). However, the ability of PCT levels to differentiate BSI from non-BSI episodes has not been evaluated in nosocomial BSI.

METHODS

We retrospectively reviewed the medical records of patients ≥ 18 years of age with suspected BSI that developed more than 48 hours after admission.

RESULTS

Of the 785 included patients, 105 (13.4%) had BSI episodes and 680 (86.6%) had non-BSI episodes. The median serum PCT level was elevated in patients with BSI as compared with those without BSI (0.65 ng/mL vs. 0.22 ng/mL, p = 0.001). The optimal PCT cut-off value of BSI was 0.27 ng/mL, with a corresponding sensitivity of 74.6% (95% confidence interval [CI], 66.4% to 81.7%) and a specificity of 56.5% (95% CI, 52.7% to 60.2%). The area under curve of PCT (0.692) was significantly larger than that of C-reactive protein (CRP; 0.526) or white blood cell (WBC) count (0.518). However, at the optimal cut-off value, PCT failed to predict BSI in 28 of 105 cases (26.7%). The PCT level was significantly higher in patients with an eGFR < 60 mL/min/1.73 m² than in those with an eGFR ≥ 60 mL/min/1.73 m² (0.68 vs. 0.17, p = 0.01).

CONCLUSIONS

PCT was more useful for predicting nosocomial BSI than CRP or WBC count. However, the diagnostic accuracy of predicting BSI remains inadequate. Thus, PCT is not recommended as a single diagnostic tool to avoid taking blood cultures in the nosocomial setting.

Multicenter observational study to evaluate epidemiology and resistance patterns of common intensive care unit-infections

Background:

There is limited data regarding the microbiology of Intensive Care Unit (ICU)-acquired infections, such as ventilator-associated pneumonia (VAP), catheter-associated urinary tract infections (CAUTI), and catheter-related bloodstream infections (CRBSI) from India.

Objectives:

To explore the microbiology and resistance patterns of ICU-acquired infections and evaluate their outcomes.

Materials and Methods:

This was a multicenter observational study, conducted by Indian Society of Critical Care Medicine (MOSER study) between August 2011 and October 2012. Patients in the ICU ≥48 h with any ICU-acquired infection within 14 days of index ICU stay were included. Patient demographics, relevant clinical, and microbiological details were collected. Follow-up until hospital discharge or death was done, and 6-month survival data were collected.

Results:

Of the 381 patients included in the study, 346 patients had 1 ICU infection and 35 had more than one ICU infection. Among patients with single infections, 223 had VAP with Acinetobacter being the most common isolate. CAUTI was seen in 42 patients with Klebsiella as the most common organism. CRBSI was seen in 81 patients and Klebsiella was the most common causative organism. Multidrug resistance was noted in 87.5% of Acinetobacter, 75.5% of Klebsiella, 61.9% of Escherichia coli, and 58.9% of Pseudomonas isolates, respectively. Staphylococcus constituted only 2.4% of isolates. Mortality rates were 26%, 11.9%, and 34.6% in VAP, CAUTI, and CRBSI, respectively.

Conclusion:

VAP is the most common infection followed by CRBSI and CAUTI. Multidrug-resistant Gram-negative bacteria are the most common organisms. Staphylococcus aureus is uncommon in the Indian setting.

Humoral immune consequences of Staphylococcus aureus ST239-associated bacteremia

The humoral immune responses against 46 different staphylococcal antigens in 27 bacteremia patients infected by clonally related methicillin-resistant Staphylococcus aureus (MRSA) strains of a single sequence type (ST) 239 were investigated. A group of non-infected patients (n = 31) hospitalized for different reasons served as controls. All strains were confirmed as ST 239 by S. aureus and mecA-specific PCR, spa, and multi-locus sequence typing (MLST). In each bacteremia patient, a unique pattern of S. aureus antigen-specific immune responses after infection was observed. Antibody levels among bacteremia patients were significantly higher than controls for HlgB (P = 0.001), LukD (P = 0.009), LukF (P = 0.0001), SEA (P = 0.0001), SEB (P = 0.011), SEC (P = 0.010), SEQ (P = 0.049), IsaA (P = 0.043), IsdA (P = 0.038), IsdH (P = 0.01), SdrD (P = 0.001), SdrE (P = 0.046), EsxA (P = 0.0001), and SA0104 (P = 0.0001). On the other hand, the antibody levels were significantly higher among controls for SSL3 (P = 0.009), SSL9 (P = 0.002), and SSL10 (P = 0.007) when the IgG level on the day of infection was compared with that measured on the day of admission. Diversity was observed in the immune response against the antigens. However, a set of antigens (IsaA, IsdA, IsdH, SdrD, and HlgB) triggered a similar type of immune response in different individuals. We suggest that these antigens could be considered when developing a multi-component (passive) vaccine. SEA and/or its specific antibodies seem to play a critical role during ST239 MRSA bacteremia and SEA-targeted therapy may be a strategy to be considered.

Identification of small molecules that disrupt vacuolar function in the pathogen Candida albicans

The fungal vacuole is a large acidified organelle that performs a variety of cellular functions. At least a sub-set of these functions are crucial for pathogenic species of fungi, such as Candida albicans, to survive within and invade mammalian tissue as mutants with severe defects in vacuolar biogenesis are avirulent. We therefore sought to identify chemical probes that disrupt the normal function and/or integrity of the fungal vacuole to provide tools for the functional analysis of this organelle as well as potential experimental therapeutics. A convenient indicator of vacuolar integrity based upon the intracellular accumulation of an endogenously produced pigment was adapted to identify Vacuole Disrupting chemical Agents (VDAs). Several chemical libraries were screened and a set of 29 compounds demonstrated to reproducibly cause loss of pigmentation, including 9 azole antifungals, a statin and 3 NSAIDs. Quantitative analysis of vacuolar morphology revealed that (excluding the azoles) a sub-set of 14 VDAs significantly alter vacuolar number, size and/or shape. Many C. albicans mutants with impaired vacuolar function are deficient in the formation of hyphal elements, a process essential for its pathogenicity. Accordingly, all 14 VDAs negatively impact C. albicans hyphal morphogenesis. Fungal selectivity was observed for approximately half of the VDA compounds identified, since they did not alter the morphology of the equivalent mammalian organelle, the lysosome. Collectively, these compounds comprise of a new collection of chemical probes that directly or indirectly perturb normal vacuolar function in C. albicans.

Hickman to central venous catheter: A case of difficult venous access in a child suffering from acute lymphoblastic leukemia

Chemotherapy in children suffering from cancer usually requires placement of an indwelling central venous catheter (CVC). A child may need to undergo repeated procedures because of infection and occlusion of previous access devices. We present a case of CVC insertion in a child suffering from acute lymphoblastic leukemia where an innovative technique was employed.

ICU-acquired candidemia within selective digestive decontamination studies: a meta-analysis

PURPOSE

To estimate the direct and indirect (contextual) effects of the factorized constituents of selective digestive decontamination and selective oropharyngeal decontamination (SDD/SOD), being topical antibiotic (TA) and protocolized antifungal prophylaxis (PAFP), on ICU-acquired candidemia.

METHODS

A broad range of ICU candidemia incidence studies were sourced to serve as points of reference. The candidemia incidence was extracted from component (control and intervention) groups decanted from studies of various designs (concurrent or non-concurrent) and whether investigating SDD/SOD versus non-TA methods of ICU infection prevention. The candidemia incidences were summarized in regression models using generalized estimating equation (GEE) methods. Groups derived from observational studies (no prevention method under study) provided an overarching external benchmark candidemia incidence for calibration.

RESULTS

Within studies investigating SDD/SOD, the mean (and 95% confidence interval) candidemia incidence among concurrent component groups (40 control; 2.4%; 1.7-3.2% and 43 intervention groups; 2.4%; 1.6-3.1%), but not non-concurrent control groups (11 groups; 1.6%; 0.1-2.7%), is higher than that of the benchmark candidemia incidence derived from 54 observational groups (1.5%; 1.2-1.9%). The TA constituent within SDD/SOD has significant direct and indirect (contextual) effects in GEE models even after adjusting for the publication year and the group-wide presence of either candidemia risk factors or PAFP use.

CONCLUSION

The TA constituent of SDD/SOD is associated with a contextual effect on candidemia incidence which is similar in magnitude to that of the conventional candidemia risk factors and against which PAFP partially attenuates. This increase is inapparent within individual SDD/SOD studies examined in isolation.

Nosocomial infections in the intensive care unit: Incidence, risk factors, outcome and associated pathogens in a public tertiary teaching hospital of Eastern India

BACKGROUND

The increased morbidity and mortality associated with nosocomial infections in the intensive care unit (ICU) is a matter of serious concern today.

AIMS

To determine the incidence of nosocomial infections acquired in the ICU, their risk factors, the causative pathogens and the outcome in a tertiary care teaching hospital.

MATERIALS AND METHODS

This was a prospective observational study conducted in a 12 bedded combined medical and surgical ICU of a medical college hospital. The study group comprised 242 patients admitted for more than 48 h in the ICU. Data were collected regarding severity of the illness, primary reason for ICU admission, presence of risk factors, presence of infection, infecting agent, length of ICU and hospital stay, and survival status and logistic regression analysis was done.

RESULTS

The nosocomial infection rate was 11.98% (95% confidence interval 7.89-16.07%). Pneumonia was the most frequently detected infection (62.07%), followed by urinary tract infections and central venous catheter associated bloodstream infections. Prior antimicrobial therapy, urinary catheterization and length of ICU stay were found to be statistically significant risk factors associated with nosocomial infection. Nosocomial infection resulted in a statistically significant increase in length of ICU and hospital stay, but not in mortality.

CONCLUSION

Nosocomial infections increase morbidity of hospitalized patients. These findings can be utilized for planning nosocomial infection surveillance program in our setting.

LTX-109 is a novel agent for nasal decolonization of methicillin-resistant and -sensitive Staphylococcus aureus

Nasal decolonization has a proven effect on the prevention of severe Staphylococcus aureus infections and the control of methicillin-resistant S. aureus (MRSA). However, rising rates of resistance to antibiotics highlight the need for new substances for nasal decolonization. LTX-109 is a broad-spectrum, fast-acting bactericidal antimicrobial drug for topical treatment, which causes membrane disruption and cell lysis. This mechanism of action is not associated with cross-resistance and has a low propensity for development of resistance. In the present study, persistent nasal MRSA and methicillin-sensitive S. aureus (MSSA) carriers were treated for 3 days with vehicle or with 1%, 2%, or 5% LTX-109. A significant effect on nasal decolonization was observed already after 2 days of LTX-109 treatment in subjects treated with 2% or 5% LTX-109 compared to vehicle (P ≤ 0.0012 by Dunnett's test). No safety issues were noted during the 9-week follow-up period. Minimal reversible epithelial lesions were observed in the nasal cavity. The systemic exposure was very low, with a maximum concentration of drug in plasma (Cmax) at 1 to 2 h postdosing (3.72 to 11.7 ng/ml). One week after treatment initiation, LTX-109 was not detectable in any subject. Intranasal treatment of S. aureus with LTX-109 is safe and reduces the bacterial load already after a single day of treatment. Hence, LTX-109 has potential as a new and effective antimicrobial agent with a low propensity of resistance development that can prevent infections by MSSA/MRSA during hospitalization. (This study has been registered at ClinicalTrials.gov under registration no. NCT01158235.).

Combination therapy with iron chelation and vancomycin in treating murine staphylococcemia

Iron acquisition is a virulence factor for Staphylococcus aureus. We assessed the efficacy of the iron chelator, deferasirox (Def), alone or in combination with vancomycin (Van) against two methicillin-resistant S. aureus (MRSA) strains in vitro and in a murine bacteremia model. In vitro time-kill assays were carried out against MRSA or vancomycin-intermediate S. aureus (VISA) strains. The impact of Def on Van binding to the surface of S. aureus was measured by flow cytometry. Furthermore, we compared the efficacy of Def, Van, or both drugs in treating S. aureus bacteremia in a murine model. Combination therapy reduced MRSA and VISA viability in vitro versus either drug alone or untreated controls (p < 0.005); this outcome was correlated with enhanced Van surface binding to S. aureus cells. In vivo, Def + Van combination therapy significantly reduced the bacterial burden in mice kidneys (p = 0.005) and spleen (p < 0.001), and reduced the severity of infection with MRSA or VISA strains compared to placebo-treated mice. Our results show that Def enhances the in vitro and in vivo capacity of Van-mediated MRSA killing via a mechanism that appears to involve increased binding of Van to the staphylococcal surface. Iron chelation is a promising, novel adjunctive therapeutic strategy for MRSA and VISA infections.

Effect of statin use on outcomes of adults with candidemia

Background

Statins have immunomodulatory properties and hinder Candida growth. However, it is unknown whether they may improve prognosis in patients with candidemia. We sought to determine the effect of prior statin use on the clinical outcomes of patients suffering candidemia.

Methods and Findings

Multicenter cohort study of hospitalized adults with candidemia between 2005 and 2011 in six hospitals in Spain, Brazil and Argentina. Of 326 candidemias, 44 (13.5%) occurred in statin users and 282 (86.5%) in statin non-users. The median value of APACHE II at candidemia diagnosis was similar between groups (18 vs. 16; p=.36). Candida albicans was the most commonly isolated species, followed by C. parapsilosis, C. tropicalis, C. glabrata, and C. krusei. There were no differences regarding appropriate empirical antifungal treatment. Statin users had a lower early (5 d) case-fatality rate than non-users (4.5 vs. 17%; p=.031). This effect was not observed with other cardiovascular drugs (aspirin, beta blockers and ACE inhibitors). Independent factor related to early case-fatality rate was APACHE II score (AOR, 1.08; 95% CI, 1.03–1.14; p=.002). An appropriate empirical antifungal therapy (AOR, 0.11; 95% CI, 0.04–0.26; p=<.001) and prior statin use were independently associated with lower early case-fatality (AOR, 0.17; 95% CI, 0.03–0.93; p=.041). Fourteen days (14d) and overall (30d) case-fatality rates were similar between groups (27% vs. 29%; p=0.77 and 40% vs. 44%; p=.66).

Conclusions

The use of statins might have a beneficial effect on outcomes of patients with candidemia. This hypothesis deserves further evaluation in randomized trials.

Characterization of a mouse-adapted Staphylococcus aureus strain

More effective antibiotics and a protective vaccine are desperately needed to combat the ‘superbug’ Staphylococcus aureus. While in vivo pathogenicity studies routinely involve infection of mice with human S. aureus isolates, recent genetic studies have demonstrated that S. aureus lineages are largely host-specific. The use of such animal-adapted S. aureus strains may therefore be a promising approach for developing more clinically relevant animal infection models. We have isolated a mouse-adapted S. aureus strain (JSNZ) which caused a severe outbreak of preputial gland abscesses among male C57BL/6J mice. We aimed to extensively characterize this strain on a genomic level and determine its virulence potential in murine colonization and infection models. JSNZ belongs to the MLST type ST88, rare among human isolates, and lacks an hlb-converting phage encoding human-specific immune evasion factors. Naive mice were found to be more susceptible to nasal and gastrointestinal colonization with JSNZ than with the human-derived Newman strain. Furthermore, naïve mice required antibiotic pre-treatment to become colonized with Newman. In contrast, JSNZ was able to colonize mice in the absence of antibiotic treatment suggesting that this strain can compete with the natural flora for space and nutrients. In a renal abscess model, JSNZ caused more severe disease than Newman with greater weight loss and bacterial burden. In contrast to most other clinical isolates, JSNZ can also be readily genetically modified by phage transduction and electroporation. In conclusion, the mouse-adapted strain JSNZ may represent a valuable tool for studying aspects of mucosal colonization and for screening novel vaccines and therapies directed at preventing colonization.

Visual analysis of DNA microarray data for accurate molecular identification of non-albicans Candida isolates from patients with candidemia episodes

The performance of a visual slide-based DNA microarray for the identification of non-albicans Candida spp. was evaluated. Among 167 isolates that had previously been identified by Vitek 2, the agreement between DNA microarray and sequencing results was 97.6%. This DNA microarray platform showed excellent performance.

Characterization of the humoral immune response during Staphylococcus aureus bacteremia and global gene expression by Staphylococcus aureus in human blood

Attempts to develop an efficient anti-staphylococcal vaccine in humans have so far been unsuccessful. Therefore, more knowledge of the antigens that are expressed by Staphylococcus aureus in human blood and induce an immune response in patients is required. In this study we further characterize the serial levels of IgG and IgA antibodies against 56 staphylococcal antigens in multiple serum samples of 21 patients with a S. aureus bacteremia, compare peak IgG levels between patients and 30 non-infected controls, and analyze the expression of 3626 genes by two genetically distinct isolates in human blood. The serum antibody levels were measured using a bead-based flow cytometry technique (xMAP®, Luminex corporation). Gene expression levels were analyzed using a microarray (BµG@s microarray). The initial levels and time taken to reach peak IgG and IgA antibody levels were heterogeneous in bacteremia patients. The antigen SA0688 was associated with the highest median initial-to-peak antibody fold-increase for IgG (5.05-fold) and the second highest increase for IgA (2.07-fold). Peak IgG levels against 27 antigens, including the antigen SA0688, were significantly elevated in bacteremia patients versus controls (P≤0.05). Expression of diverse genes, including SA0688, was ubiquitously high in both isolates at all time points during incubation in blood. However, only a limited number of genes were specifically up- or downregulated in both isolates when cultured in blood, compared to the start of incubation in blood or during incubation in BHI broth. In conclusion, most staphylococcal antigens tested in this study, including many known virulence factors, do not induce uniform increases in the antibody levels in bacteremia patients. In addition, the expression of these antigens by S. aureus is not significantly altered by incubation in human blood over time. One immunogenic and ubiquitously expressed antigen is the putative iron-regulated ABC transporter SA0688.

Sepsis, severe sepsis and septic shock: changes in incidence, pathogens and outcomes

Sepsis has been around since the dawn of time, having been described for more than 2000 years, although clinical definitions are recent. The consensus sepsis definitions have permitted worldwide epidemiological studies of sepsis to be conducted. We now recognize the common nature of sepsis and the consistency of its disease - particularly severe sepsis and septic shock. The incidence of sepsis, severe sepsis and septic shock continues to increase, and although Gram-positive bacterial pathogens remain the most common cause of sepsis, fungal organisms are increasing rapidly. We have made progress over the past half-century in identifying and treating patients with sepsis, and decreasing fatality rates reflect this progress. However, owing to the increasing incidence of sepsis, the number of people who die each year continues to increase. The mortality with sepsis, particularly related to treating organ dysfunction, remains a priority to clinicians worldwide and is deserving of greater public health attention.

Canadian clinical practice guidelines for invasive candidiasis in adults

Candidemia and invasive candidiasis (C/IC) are life-threatening opportunistic infections that add excess morbidity, mortality and cost to the management of patients with a range of potentially curable underlying conditions. The Association of Medical Microbiology and Infectious Disease Canada developed evidence-based guidelines for the approach to the diagnosis and management of these infections in the ever-increasing population of at-risk adult patients in the health care system. Over the past few years, a new and broader understanding of the epidemiology and pathogenesis of C/IC has emerged and has been coupled with the availability of new antifungal agents and defined strategies for targeting groups at risk including, but not limited to, acute leukemia patients, hematopoietic stem cell transplants and solid organ transplants, and critical care unit patients. Accordingly, these guidelines have focused on patients at risk for C/IC, and on approaches of prevention, early therapy for suspected but unproven infection, and targeted therapy for probable and proven infection.

Trends in mortality from septicaemia and pneumonia with economic development: an age-period-cohort analysis

Background

Hong Kong population has experienced drastic changes in its economic development in the 1940s. Taking advantage of Hong Kong’s unique demographic and socioeconomic history, characterized by massive, punctuated migration waves from Southern China, and recent, rapid transition from a pre-industrialized society to the first ethnic Chinese community reaching “first world” status over the last 60 years (i.e., in two or three generations), we examined the longitudinal trends in infection related mortality including septicemia compared to trends in non-bacterial pneumonia to generate hypotheses for further testing in other recently transitioned economies and to provide generalized aetiological insights on how economic transition affects infection-related mortality.

Methods

We used deaths from septicemia and pneumonia not specified as bacterial, and population figures in Hong Kong from 1976–2005. We fitted age-period-cohort models to decompose septicemia and non-bacterial pneumonia mortality rates into age, period and cohort effects.

Results

Septicaemia-related deaths increased exponentially with age, with a downturn by period. The birth cohort curves had downward inflections in both sexes in the 1940s, with a steeper deceleration for women. Non-bacterial pneumonia-related deaths also increased exponentially with age, but the birth cohort patterns showed no downturns for those born in the 1940s.

Conclusion

The observed changes appeared to suggest that better early life conditions may enable better development of adaptive immunity, thus enhancing immunity against bacterial infections, with greater benefits for women than men. Given the interaction between the immune system and the gonadotropic axis, these observations are compatible with the hypothesis that upregulation of the gonadotropic axis underlies some of the changes in disease patterns with economic development.

Prevalence and population structure of Staphylococcus aureus nasal carriage in healthcare workers in a general population. The Tromsø Staph and Skin Study

Healthcare workers (HCWs) may be a reservoir for Staphylococcus aureus transmission to patients. We examined whether HCW status is associated with S. aureus nasal carriage and population structure (spa types) in 1302 women (334 HCWs) and 977 men (71 HCWs) aged 30–69 years participating in the population-based Tromsø Study in 2007–2008. Multivariable logistic regression models were used. While no methicillin-resistant S. aureus (MRSA) was isolated, overall, 26·2% of HCWs and 26·0% of non-HCWs were S. aureus nasal carriers. For women overall and women residing with children, the odds ratios for nasal carriage were 1·54 [95% confidence interval (CI) 1·09–2·19] and 1·86 (95% CI 1·14–3·04), respectively, in HCWs compared to non-HCWs. Moreover, HCWs vs. non-HCWs had a 2·17 and 3·16 times higher risk of spa types t012 and t015, respectively. This supports the view that HCWs have an increased risk of S. aureus nasal carriage depending on gender, family status and spa type.

Incidence and clinical implication of nosocomial infections associated with implantable biomaterials - catheters, ventilator-associated pneumonia, urinary tract infections

Health care associated infections, the fourth leading cause of disease in industrialised countries, are a major health issue. One part of this condition is based on the increasing insertion and implantation of prosthetic medical devices, since presence of a foreign body significantly reduces the number of bacteria required to produce infection. The most significant hospital-acquired infections, based on frequency and potential severity, are those related to procedures e.g. surgical site infections and medical devices, including urinary tract infection in catheterized patients, pneumonia in patients intubated on a ventilator and bacteraemia related to intravascular catheter use. At least half of all cases of nosocomial infections are associated with medical devices.Modern medical and surgical practices have increasingly utilized implantable medical devices of various kinds. Such devices may be utilized only short-time or intermittently, for months, years or permanently. They improve the therapeutic outcome, save human lives and greatly enhance the quality of life of these patients. However, plastic devices are easily colonized with bacteria and fungi, able to be colonized by microorganisms at a rate of 0.5 cm per hour. A thick biofilm is formed within 24 hours on the entire surface of these plastic devices once inoculated even with a small initial number of bacteria.The aim of the present work is to review the current literature on causes, frequency and preventive measures against infections associated with intravascular devices, catheter-related urinary tract infection, ventilator-associated infection, and infections of other implantable medical devices. Raising awareness for infection associated with implanted medical devices, teaching and training skills of staff, and establishment of surveillance systems monitoring device-related infection seem to be the principal strategies used to achieve reduction and prevention of such infections. The intelligent use of suitable antiseptics in combination with medical devices may further support reduction and prevention of such infections. In addition to reducing the adverse clinical outcomes related with these infections, such reduction may substantially decrease the economic burden caused by device-related infection for health care systems.

Methicillin-susceptible ST398 Staphylococcus aureus responsible for bloodstream infections: an emerging human-adapted subclone?

In the course of an annual 3-month bloodstream infections (BSI) survey conducted during a four-year period in 31 healthcare institutions located in three noncontiguous French regions, we report 18 ST398 Staphylococcus aureus BSI. ST398 BSI incidence showed a seven-fold increase during the study period (0.002 per 1,000 patient days in 2007 vs. 0.014 in 2010). ST398 BSI isolates differed from the pig-borne multiresistant clone: 17/18 BSI isolates were methicillin susceptible and none was of t011, t034 or t108 pig-borne spa-types. ST398 BSI isolates had homogenous resistance patterns (15/18 with only Ery^r) and prophagic content (all harboured the hlb-converting Sau3int phage). The clustering of BSI and pig-borne isolates by spa-typing and MLVA, the occurrence of Sau3int phage in BSI isolates and the lack of this phage in pig-borne isolates suggest that the emergence of BSI isolates could have arisen from horizontal transfer, at least of the Sau3int phage, in genetically diverse MSSA ST398 isolates. The acquisition of the phage likely plays a role in the increasing ability of the lysogenic ST398 isolates to colonize human. The mode of acquisition of the non pig-borne ST398 isolates by our 18 patients remains unclear. ST398 BSI were diagnosed in patients lacking livestock exposure and were significantly associated with digestive portals of entry (3/18 [16.7%] for ST398 vs. 19/767 [2.5%] for non ST398 BSI; p = .012). This raises the question of possible foodborne human infections. We suggest the need for active surveillance to study and control the spread of this human-adapted subclone increasingly isolated in the hospital setting.

What do central venous catheter-associated bloodstream infections have to do with bundles?g

Interest in the patient safety agenda continues to grow in North America. In the United States (US), the Institute for Healthcare Improvement (IHI) has begun a campaign to make health care safer and more effective by encouraging hospitals to implement interventions they believe can avoid 100,000 deaths between January 2005 and July 2006 (1). The IHI, a not-for-profit organization founded in 1991, promotes the improvement of health by advancing the quality and value of health care (2). Three of the six areas for action chosen by the IHI for their '100,000 Lives Campaign' relate to prevention of nosocomial infections: central line infections, surgical site infections and ventilator-associated pneumonia. In Canada, a grassroots patient safety campaign modelled after the IHI's '100,000 Lives Campaign' has formed (3). This 'Safer Healthcare Now!' campaign focuses on the same six strategies chosen for the '100,000 Lives Campaign'. Across the country, hospitals are being invited to join the 'Safer Healthcare Now!' campaign.

Epidemiology and virulence insights from MRSA and MSSA genome analysis

Staphylococcus aureus is a major human pathogen responsible for a wide diversity of infections ranging from localized to life threatening diseases. From 1961 and the emergence of methicillin-resistant S. aureus (MRSA), this bacterium has shown a particular capacity to survive and adapt to drastic environmental changes and since the beginning of the 1990s it has spread worldwide. Until recently, S. aureus was considered as the prototype of a nosocomial pathogen but it has now been recognized as an agent responsible for outbreaks in the community. Several recent reports suggest that the epidemiology of MRSA is changing. Understanding of pathogenicity, virulence and emergence of epidemic clones within MRSA populations is not clearly defined, despite several attempts to identify common molecular features between strains that share similar epidemiological and/or virulence behavior. These studies included: pattern profiling of bacterial adhesins, analysis of clonal complex groups, molecular genotyping and enterotoxin content analysis. To date, all approaches failed to find a correlation between molecular determinants and clinical outcomes. We hypothesize that the capacity of the bacterium to become more invasive or virulent is determined by genetics. The utilization of massively parallel methods of analysis is therefore ideal to study the contribution of genetics. Therefore, this article focuses on the entire genome including coding sequences as well as noncoding sequences. This high resolution approach allows the monitoring micro- and macroevolution of MRSA and identification of specific genomic markers of evolution of invasive or highly virulent phenotypes.

Identifying possible deaths associated with nosocomial infection in a hospital by data mining

BACKGROUND

Nosocomial infection (NI) is a cause of patient morbidity and mortality. Conducting an audit of deaths due to NI is a potentially useful approach to improving professional standards. In France, these deaths are required to be reported, but the reporting is left to clinicians, who often do not comply. The aim of the present study was to assess whether linking the microbiological database with the hospital mortality database might be a suitable surveillance approach for identifying patients who died with an NI.

METHODS

A total of 1,726 deaths were recorded in the mortality database of a French university hospital between September 1, 2006, and September 16, 2007. During this same period, 6,290 potential NIs (PNIs) were identified by bacteriological examination. These PNIs were generated using a computer algorithm specific to the bacteriology database. PNI information request forms were sent to the senior doctor of the unit where the samples had been obtained to determine whether the PNI was an NI, colonization, or a non-nosocomial infection. A total of 364 cases were common to both databases; from these, a sample of 135 cases was selected for further analysis. To establish the strength of evidence for NI as the cause of death, the 135 cases were analyzed using the patient record by an investigator from the hospital hygiene team.

RESULTS

During the study period, no deaths associated with NI were reported spontaneously. Of the 135 cases analyzed, NI was considered the main cause of death in 6 (4.4%) and a contributory factor in 51 (37.8%). Thus, NI was estimated to be the main cause of death in 0.9% of all patients who died in the hospital during the study period and a contributory cause in another 8.0% of these patients.

CONCLUSION

Linking databases from bacteriology with those containing hospital mortality records is a simple, reproducible tool for identifying the number of deaths attributable to NI. This may provide a powerful approach to help reduce the burden of disease due to NI through the auditing of such identified deaths.

IL-12 and related cytokines: function and regulatory implications in Candida albicans infection

IL-12 is a cytokine with links to both innate and adaptive immunity systems. In mice, its deletion leads to acute susceptibility to oral infection with the yeast Candida albicans, whereas such mice are resistant to systemic disease. However, it is an essential component of the adaptive response that leads to the generation of Th1-type cytokine responses and protection against disseminated disease. This paper presents an overview of the role of IL-12 in models of systemic and mucosal infection and the possible relationships between them.

Nationwide sentinel surveillance of bloodstream Candida infections in 40 tertiary care hospitals in Spain

Candidemia studies have documented geographic differences in rates and epidemiology, underscoring the need for surveillance to monitor trends. We conducted prospective candidemia surveillance in Spain to assess the incidence, species distribution, frequency of antifungal resistance, and risk factors for acquiring a Candida infection. Prospective laboratory-based surveillance was conducted from June 2008 to June 2009 in 40 medical centers located around the country. A case of candidemia was defined as the isolation of a Candida species from a blood culture. Incidence rates were calculated per 1,000 admissions. Antifungal susceptibility tests were performed by using broth microdilution assay according to the guidelines of the Clinical and Laboratory Standards Institute. We detected 984 cases, for an overall incidence of 1.09 cases per 1,000 admissions. The crude mortality was 20.20%. Candida albicans was the most common species (49.08%), followed by C. parapsilosis (20.73%), C. glabrata (13.61%), and C. tropicalis (10.77%). Overall, decreased susceptibility to fluconazole occurred in 69 (7.01%) incident isolates. Antifungal resistance was rare, and a moderate linear correlation between fluconazole and voriconazole MICs was observed. This is the largest multicenter candidemia study conducted to date and shows the substantial morbidity and mortality of candidemia in Spain.

Risk factors and mortality of nosocomial infections of methicillin-resistant Staphylococcus aureus in an intensive care unit

PURPOSE

Methicillin-resistant Staphylococcus aureus (MRSA) infections are an increasing worldwide problem. We determined risk factors and predictors of mortality of MRSA nosocomial infections (NIs).

MATERIALS AND METHODS

A prospective cohort study was performed in an adult mixed medical and surgical intensive care unit from 2003 to 2007. Stratified analyses and generalized linear modeling were used to assess risk factors and predictors of infection and mortality.

RESULTS

A total of 184 infections (3.6% of all infections) were due to S aureus, and 97.8% of these were methicillin resistant. The most common infection sites were respiratory tract (35.6%) and bloodstream (30.6%). Stratified analyses of length of stay (LOS) before onset of MRSA NI and death indicated that MRSA infection (odds ratio [OR], 38.49; 95% confidence interval [CI], 25.53-58.09) and mortality (OR, 4.72; 95% CI, 1.92-11.99) were more likely for LOS more than 15 days than for LOS less than 7 days. After controlling for potentially confounding factors by use of generalized linear modeling analysis, we identified the following as independent risk factors: LOS before onset of MRSA infection (OR, 1.03; 95% CI, 0.01-1.04), serum creatinine (OR, 5.87; 95% CI, 1.37-9.21) level, use of mechanical ventilator (OR, 6.71; 95% CI, 1.58-8.5), and central venous catheter (OR, 1.13; 95% CI, 1.05-1.31).

CONCLUSIONS

Methicillin resistance is very common with S aureus infection. In our intensive care unit, use of invasive devices/procedures and LOS were the most important risk factors for infection.

Long term trends in the occurrence of nosocomial blood stream infection

OBJECTIVE

To determine trends in the occurrence of nosocomial blood stream infection at the University of Alberta Hospital.

METHODS

A prospective survey of nosocomial blood stream infection was conducted; cases from August 1986 to December 1996 were reviewed. Cases were detected by a review of positive blood cultures reported by the microbiology laboratory. Centers for Disease Control and Prevention definitions of nosocomial infection were used to categorize isolates as nosocomial, community acquired or contaminant.

RESULTS

There were 2389 cases; primary bacteremia was the most common source (57%), followed by urinary tract, respiratory tract and surgical site sources (10% each). The nosocomial blood steam infection rate rose progressively from 6.0/1000 admissions and 4.59/10,000 patient days in 1986 to 11.2/1000 admissions and 14.31/10,000 days in 1996 (P<0.01); 48% of the total increase in rate occurred between 1995 and 1996. Significant increases occurred between 1986 and 1996 in primary infections (from 3.2 to 7.5/1000 admissions, P<0.01) and infections from all secondary sources (from 2.5 to 3.8/1000 admissions, P=0.01). Coagulase-negative staphylococci (27%), Staphylococcus aureus (19%) and enterococci (9%) were the most common microbial causes. Aerobic Gram-negative bacilli accounted for 28% and candida for 6%. Coagulase-negative staphylococci, enterococci and candida all became more prevalent as causes of infection over the study period.

CONCLUSIONS

The nosocomial blood stream infection rate in the hospital has nearly doubled in the past 10 years, largely due to increased primary bacteremia.

Heterogeneity of the humoral immune response following Staphylococcus aureus bacteremia

Expanding knowledge on the humoral immune response in Staphylococcus aureus-infected patients is a mandatory step in the development of vaccines and immunotherapies. Here, we present novel insights into the antibody responses following S. aureus bacteremia. Fifteen bacteremic patients were followed extensively from diagnosis onwards (median 29 days, range 9–74). S. aureus strains (median 3, range 1–6) and serial serum samples (median 16, range 6–27) were collected. Strains were genotyped by pulsed-field gel electrophoresis (PFGE) and genes encoding 19 staphylococcal proteins were detected by polymerase chain reaction (PCR). The levels of IgG, IgA, and IgM directed to these proteins were determined using bead-based flow cytometry. All strains isolated from individual patients were PFGE-identical. The genes encoding clumping factor (Clf) A, ClfB, and iron-responsive surface-determinant (Isd) A were detected in all isolates. Antigen-specific IgG levels increased more frequently than IgA or IgM levels. In individual patients, different proteins induced an immune response and the dynamics clearly differed. Anti-ClfB, anti-IsdH, and anti-fibronectin-binding protein A IgG levels increased in 7 of 13 adult patients (p < 0.05). The anti-IsdA IgG level increased in 12 patients (initial to peak level: 1.13–10.72 fold; p < 0.01). Peak level was reached 7–37 days after diagnosis. In a bacteremic 5-day-old newborn, antistaphylococcal IgG levels declined from diagnosis onwards. In conclusion, each bacteremic patient develops a unique immune response directed to different staphylococcal proteins. Therefore, vaccines should be based on multiple components. IsdA is immunogenic and, therefore, produced in nearly all bacteremic patients. This suggests that IsdA might be a useful component of a multivalent staphylococcal vaccine.

Patterns of mortality and causes of death in polytrauma patients--has anything changed?

INTRODUCTION

Numerous articles have examined the pattern of traumatic deaths. Most of these studies have aimed to improve trauma care and raise awareness of avoidable complications. The aim of the present review is to evaluate whether the distribution of complications and mortality has changed.

MATERIALS AND METHODS

A review of the published literature to identify studies examining patterns and causes of death following trauma treated in level 1 hospitals published between 1980 and 2008. PubMed was searched using the following terms: Trauma Epidemiology, Injury Pattern, Trauma Deaths, and Causes of Death. Three time periods were differentiated: (n=6, 1980-1989), (n=6, 1990-1999), and (n=10, 2000-2008). The results were limited to the English and/or German language. Manuscripts were analysed to identify the age, injury severity score (ISS), patterns and causes of death mentioned in studies.

RESULTS

Twenty-two publications fulfilled the inclusion criteria for the review. A decrease of haemorrhage-induced deaths (25-15%) has occurred within the last decade. No considerable changes in the incidence and pattern of death were found. The predominant cause of death after trauma continues to be central nervous system (CNS) injury (21.6-71.5%), followed by exsanguination (12.5-26.6%), while sepsis (3.1-17%) and multi-organ failure (MOF) (1.6-9%) continue to be predominant causes of late death.

DISCUSSION

Comparing manuscripts from the last three decades revealed a reduction in the mortality rate from exsanguination. Rates of the other causes of death appear to be unchanged. These improvements might be explained by developments in the availability of multislice CT, implementation of ATLS concepts and logistics of emergency rescue.

Impact of AmpC overexpression on outcomes of patients with Pseudomonas aeruginosa bacteremia

AmpC overexpression (AmpC++) is a significant mechanism of beta-lactam resistance in Pseudomonas aeruginosa, but its impact on clinical outcomes is not well established. To examine the influence of AmpC++ on clinical outcomes of patients with P. aeruginosa bacteremia, we screened all bloodstream P. aeruginosa isolates obtained from 2003 to 2006 for AmpC++. Demographics and outcomes were retrospectively compared between patients with P. aeruginosa bacteremia caused by AmpC++ and pan-susceptible strains (wild-type controls). Of the 263 isolates screened, 63 (24.0%) were nonsusceptible to ceftazidime. Clinical data of 42 AmpC++ isolates from 21 patients were compared with 33 control patients. The 2 groups were similar in sex and race. Patients in the AmpC++ group was more likely to receive inappropriate empiric antibiotics (odds ratio [OR] = 67.5; 95% confidence interval [CI], 6.3-720.0) and experience microbiologic persistence (OR = 12.2; 95% CI, 1.7-87.7). In institutions with a high prevalence of AmpC++, empiric therapy with agents with activity against AmpC++ strains may be warranted.

[Results of epidemiological surveillance of hospital infections at the Clinic of Digestive System Surgery, CCS, in 2007]

INTRODUCTION

Nosocomial infections (NI) are significant medical problem in the countries worldwide. NI significance reflects in higher morbidity and mortality rates, and moreover, NIs add to longer stay and higher treatment costs. Based on data obtained from underdeveloped and developing countries, over 20% of hospitalized patients acquire some of NIs, while that proportion is 5% in developed countries.

OBJECTIVE

A) to establish the frequency of noosocomial infections at the Clinic of Digestive System Diseases, b) determine the NI incidence in accord with anatomic localizations, c) evaluate the percentage prevalence of NI causes according to anatomic localizations, and d) review the problem of resistance of NI causative agents.

MATERIAL AND METHODS

The study of NI incidence was calculated by Center for Diseases and Prevention (CDC) methodology. Sampling, cultivation, isolation, identification and sensitivity tests of cauosative agents to antimicrobial drugs, obtained from patient's material, were carried out by standard microbiological methods in Microbiological laboratory of the Emergency Center, Clinical Center of Serbia. All infections in patients hospitalized at the Clinic of Digestive System Surgery in 2007 were recorded. Data available from medical documentation as well as data obtained from interviews of medical personnel were analyzed.

RESULTS

The incidence rates of patients with NI ranged from 1.7-3.4 per 1000 hospital days. Out of a total number of recorded nosocomial infections, surgical site infections accounted for 69%, blood infections 23% and urinary tract infections 6.8%. The most frequent causative agents of surgical site infections in the last year were as follows: Pseudomonas spp (19%), followed by Staphylococcus aureus and Klebsiella spp--(18%), Acinetobacter spp (13%), and Enterococcus spp (8%). Forty percent (40%) of all blood infections verified by laboratory tests in 2007 was caused by coagulase negative Staphylococcus spp (CNS), followed by Acinetobacter spp (18%). Enterococcus spp (11%), and Staphylococcus aureus (7%). The most frequent causative agents of urinary infections were: Escherichia coli (35%) and Enterococcus spp (29%). Over 80% of Staphylococcus aureus isolates were resistant to Methicillin (MRSA) and enterobacteria produced by beta lactamase were recorded (ESBL).

CONCLUSION

Enforcement of epidemiological surveillance of nosocomial infections contributes to insight of severity of NI problem, recognition of resistance of causative agents to antibiotics and recommendation of specific preventive measures related to these infections.

Catheter-associated bloodstream infections: looking outside of the ICU

BACKGROUND

Current recommendations for the prevention of central venous catheter-associated bloodstream infections (CA-BSIs) are mostly based on data from intensive care units (ICUs). The rates of CA-BSIs appear to be higher in non-ICU wards. Until this year, no published data were available on non-ICU CA-BSIs in the United States. This article is a summary of a talk given at an industry-sponsored conference on CA-BSIs. It summarizes an original article of ours previously published in a peer-reviewed journal.

OBJECTIVE

The objective of this study was to determine the rate of CA-BSIs in non-ICU medical patients by developing a prospective surveillance program in a major tertiary care hospital. All positive blood cultures electronically detected from April 1, 2002, to April 30, 2003, were reviewed and clinical data collected by chart review.

DEFINITIONS

Catheter utilization ratio = total number of days with a central venous catheter (CVC)/total number of patient-days; catheter-associated BSIs = defined by Centers for Disease Control and Prevention criteria, eg, a patient had to have a catheter at least 48 hours before detection of infection; CA-BSI rate = CA-BSIs/1000 catheter-days.

RESULTS

The 13-month study included 7337 catheter-days and 33,174 patient-days. The overall catheter-utilization ratio was 0.22 (range, 0.19-0.25). Of 42 cases of CA-BSIs, gram-positive organisms were recovered in 24 (57%); gram-negative bacteria in 7 (17%); and Candida spp in 6 (14%). The CA-BSI rate was 5.7 (95% confidence interval: 3.4-8.0) and varied from 4.3 to 8.0. There were no significant differences in CA-BSI rates among the wards (chi(2) for linear trend, 0.42; P = .52). The overall rate of CA-BSIs decreased steadily during the study period, from 7.8 during the first 6 months to 3.9 during the following 7 months, representing a rate ratio of 0.5 (95% confidence interval: 0.27-0.93).

CONCLUSION

Benchmark data for hospital infections in the non-ICU setting are starting to become available and efforts to improve care may have greater impact here than in the ICU. Upon patient transfer out of the ICU, it should be determined whether the catheter can be removed. Educational measures targeted at non-ICU wards are warranted. First results of computer-assisted methods to facilitate surveillance of larger number of patients are promising. The Healthcare Infection Control Practices Advisory Committee recommends that CA-BSIs be publicly reported. CA-BSIs in non-ICU patients could soon be part of a mandatory reporting.

Immunological mechanisms underlying the genetic predisposition to severe Staphylococcus aureus infection in the mouse model

Host genetic variations play a significant role in conferring predisposition to infection. In this study, we examined the immune mechanisms underlying the host genetic predisposition to severe Staphylococcus aureus infection in different mouse strains. Whereas C57BL/6 mice were the most resistant in terms of control of bacterial growth and survival, A/J, DBA/2, and BALB/c mice were highly susceptible and succumbed to infection shortly after bacterial inoculation. Other strains (C3H/HeN, CBA, and C57BL/10) exhibited intermediate susceptibility levels. Susceptibility of mice to S. aureus was associated with an inability to limit bacterial growth in the kidneys and development of pathology. Resistance to S. aureus in C57BL/6 mice was dependent on innate immune mechanisms because Rag2-IL2Rgamma(-/-) C57BL/6 mice, which are deficient in B, T, and NK cells, were also resistant to infection. Indeed, neutrophil depletion or inhibition of neutrophil recruitment rendered C57BL/6 mice completely susceptible to S. aureus, indicating that neutrophils are essential for the observed resistance. Although neutrophil function is not inhibited in A/J mice, expression of neutrophil chemoattractants KC and MIP-2 peaked earlier in the kidneys of C57BL/6 mice than in A/J mice, indicating that a delay in neutrophil recruitment to the site of infection may underlie the increased susceptibility of A/J mice to S. aureus.

Fungal colonization and/or infection in non-neutropenic critically ill patients: results of the EPCAN observational study

The purpose of this paper is to determine the incidence of fungal colonization and infection in non-neutropenic critically ill patients and to identify factors favoring infection by Candida spp. A total of 1,655 consecutive patients (>18 years of age) admitted for > or = 7 days to 73 medical-surgical Spanish intensive care units (ICUs) participated in an observational prospective cohort study. Surveillance samples were obtained once a week. One or more fungi were isolated in different samples in 59.2% of patients, 94.2% of which were Candida spp. There were 864 (52.2%) patients with Candida spp. colonization and 92 (5.5%) with proven Candida infection. In the logistic regression analysis risk factors independently associated with Candida spp. infection were sepsis (odds ratio [OR] = 8.29, 95% confidence interval [CI] 5.07-13.6), multifocal colonization (OR = 3.49, 95% CI 1.74-7.00), surgery (OR = 2.04, 95% CI 1.27-3.30), and the use of total parenteral nutrition (OR = 4.37, 95% CI 2.16-8.33). Patients with Candida spp. infection showed significantly higher in-hospital and intra-ICU mortality rates than those colonized or non-colonized non-infected (P < 0.001). Fungal colonization, mainly due to Candida spp., was documented in nearly 60% of non-neutropenic critically ill patients admitted to the ICU for more than 7 days. Proven candidal infection was diagnosed in 5.5% of cases. Risk factors independently associated with Candida spp. infection were sepsis, multifocal colonization, surgery, and the use of total parenteral nutrition.

Gram-negative bacteraemia in non-ICU patients: factors associated with inadequate antibiotic therapy and impact on outcomes

BACKGROUND

A considerable number of gram-negative bacteraemias occur outside intensive care units (ICUs). Inadequate antibiotic therapy in ICUs has been associated with adverse outcomes; however, there are no prospective studies in non-ICU patients.

METHODS

A 6 month (1 August 2006-31 January 2007), prospective cohort study of non-ICU patients with gram-negative bacteraemia in a tertiary-care hospital was performed. Inadequate empirical antibiotic therapy was defined as no antibiotic or starting a non-susceptible antibiotic within 24 h after the initial positive blood culture.

RESULTS

Two hundred and fifty non-ICU patients had gram-negative bacteraemia. The mean age was 56.4 (+/-16.1) years. The predominant bacteria in monomicrobial infections were Escherichia coli (24%), Klebsiella pneumoniae (18%) and Pseudomonas aeruginosa (8%). Sixty-one (24%) patients had polymicrobial bacteraemia. Seventy patients (28%) required ICU transfer and 35 (14%) died. Seventy-nine (31.6%) received inadequate empirical antibiotic therapy. These patients were more likely to have a hospital-acquired infection [odds ratio (OR) = 1.99, 95% confidence interval (CI) = 1.11-3.56, P = 0.02] and less likely to have E. coli monomicrobial bacteraemia [OR 0.40 (95% CI 0.19-0.86), P = 0.02]. There were no differences in occurrence of sepsis [72 (91.1%) patients with inadequate versus 159 (93.0%) with adequate therapy; P = 0.6], ICU transfer [20 (25.3%) versus 50 (29.2%); P = 0.5], post-bacteraemia length of stay (median = 6.8 versus 6.1 days; P = 0.09) or death [11 (13.9%) versus 24 (14.0%); P = 1.0].

CONCLUSIONS

Nearly one-third of the non-ICU patients with gram-negative bacteraemia received inadequate empirical antibiotic therapy. There was no difference in adverse outcomes between patients receiving inadequate or adequate therapy in this study.

Risk factors and mortality in patients with nosocomial Staphylococcus aureus bacteremia

BACKGROUND

Infections due to methicillin-resistant Staphylococcus aureus have become increasingly common in hospitals worldwide. S aureus continues to be a cause of nosocomial bacteremia.

METHODS

We analyzed the clinical significance (mortality) of MRSA and methicillin-susceptible S aureus bacteremia in a retrospective cohort study in a 2900-bed tertiary referral medical center. Survival and logistic regression analyses were used to determine the risk factors and prognostic factors of mortality.

RESULTS

During the 15-year period, 1148 patients were diagnosed with nosocomial S aureus bacteremia. After controlling potential risk factors for MRSA bacteremia on logistic regression analysis, service, admission days prior to bacteremia, age, mechanical ventilator, and central venous catheter (CVC) were independent risk factors for MRSA. The crude mortality rate of S aureus bacteremia was 44.1%. The difference between the mortality rates of MRSA (49.8%) and MSSA bacteremia (27.6%) was 22.2% (P < .001). Upon logistic regression analysis, the mortality with MRSA bacteremia was revealed to be 1.78 times higher than MSSA (P < .001). The other predicted prognostic factors included age, neoplasms, duration of hospital stay after bacteremia, presence of mechanical ventilator, and use of CVC.

CONCLUSIONS

Resistance to methicillin was an important independent prognostic factor for patients with S aureus bacteremia.

[Risk factors for the appearance of central venous catheters colonisation]

INTRODUCTION/AIM

Intravascular device placement (IVD) is a part of everyday medical practice, however, its application is associated with a high risk of onset of nosocomial infections (NI) and increased mortality and morbidity. Nosocomial blood infections (NBIs) account for 10% of all the registered NI. NBIs are more frequent in patients with a placed IVD and it present an important risk factor for the onset of NBI, i.e. catheter-associated NBIs (CANBIs). Pathogenesis of CANBIs is complex and conditioned by the presence of different characteristics related to a catheter, patient and a specific causative organism. The most common CRBSI causes include coagulase-negative staphylococcus, S. aureus, Enterobacter spp, Candida spp, Klebsiella spp, Pseudomonas spp. and Enterococcus spp.

METHODS

All the patients hospitalized at the Intensive Care Department of the Clinic of Digestive Diseases over the period January 1, 2004-September 1, 2004 were retrospectively analyzed. The study included 107 patients in whom central venous catheter (CVC) was placed for more than 48 h. All the causes isolated from a CVC segment were recorded. Culture, isolation and identification of the causative organisms were performed using standard microbiological methods in the Bacteriological Laboratory within the Emergency Center, Clinical Center of Serbia. Catheter segment samples (tip of the CVC 3-5 cm long) were analyzed. Based on the insight into medical documentation, patients' examination and medical staff interview, catheter and patient-related characteristics were recorded.

RESULTS

A total of 107 CVCs were analyzed, out of which 56 (52%) were sterile while 51 (48%) were colonized. The results of our study evidenced that total parenteral nutrition (TPN) (p < 0.05), number of catheterization days (p < 0.05), and central venous pressure measurement (p < 0.05) were significantly associated with CVC colonization. In this study, no statistically significant difference in catheter colonization was found with respect to sex, age, anatomical insertion site and CVC placement site.

CONCLUSION

According to the results of our study, TPN, the number of catheterization days and measurement of central venous pressure play major roles in colonization of CVC. Understanding risk factors associated with CVC colonization and onset of CANBIs is a prerequisite for quality preventive work of health professionals.

Bench-to-bedside review: Candida infections in the intensive care unit

Invasive mycoses are life-threatening opportunistic infections and have emerged as a major cause of morbidity and mortality in critically ill patients. This review focuses on recent advances in our understanding of the epidemiology, diagnosis and management of invasive candidiasis, which is the predominant fungal infection in the intensive care unit setting. Candida spp. are the fourth most common cause of bloodstream infections in the USA, but they are a much less common cause of bloodstream infections in Europe. About one-third of episodes of candidaemia occur in the intensive care unit. Until recently, Candida albicans was by far the predominant species, causing up to two-thirds of all cases of invasive candidiasis. However, a shift toward non-albicans Candida spp., such as C. glabrata and C. krusei, with reduced susceptibility to commonly used antifungal agents, was recently observed. Unfortunately, risk factors and clinical manifestations of candidiasis are not specific, and conventional culture methods such as blood culture systems lack sensitivity. Recent studies have shown that detection of circulating β-glucan, mannan and antimannan antibodies may contribute to diagnosis of invasive candidiasis. Early initiation of appropriate antifungal therapy is essential for reducing the morbidity and mortality of invasive fungal infections. For decades, amphotericin B deoxycholate has been the standard therapy, but it is often poorly tolerated and associated with infusion-related acute reactions and nephrotoxicity. Azoles such as fluconazole and itraconazole provided the first treatment alternatives to amphotericin B for candidiasis. In recent years, several new antifungal agents have become available, offering additional therapeutic options for the management of Candida infections. These include lipid formulations of amphotericin B, new azoles (voriconazole and posaconazole) and echinocandins (caspofungin, micafungin and anidulafungin).