Microbiological factors influencing the outcome of nosocomial bloodstream infections: a 6-year validated, population-based model

Activity of novel non-amphipathic cationic antimicrobial peptides against Candida species

BACKGROUND AND OBJECTIVES

Candida species are problematic opportunistic pathogens in the hospital setting, where they are frequently associated with opportunistic infections of indwelling medical devices. There are only a few effective classes of antifungal agents currently available, and some species, such as Candida lusitaniae, Candida glabrata and Candida krusei, are intrinsically resistant to some of these drugs, further reducing existing therapeutic options. We have recently developed synthetic, non-amphipathic cationic antimicrobial peptides (CAPs) based on the structure of native hydrophobic membrane-spanning domains of integral membrane proteins. In this article, we report on the activity of these CAPs and new variants thereof against eight Candida species.

METHODS AND RESULTS

Using a combination of MIC, haemolysis, time-kill and biofilm killing assays, we demonstrate activity of CAPs in the micromolar range against eight Candida species, with little toxicity to mammalian cells. The synthetic peptides killed both the fluconazole-susceptible and fluconazole-resistant strains of Candida albicans, Candida tropicalis and C. glabrata by 4 logs or more within 3 h, and also killed pre-formed yeast biofilms on plastic surfaces.

CONCLUSIONS

These peptides show promise as a basis for development of novel, broad-spectrum antimicrobial agents.

Epidemiología de la candidemia en UCI

During the last decades there has been an important increase in the incidence of fungal infections. These infections are common in the setting of Intensive Care Units (ICU), where the prevalence of high-risk patients is important. In this review we discuss the incidence of candidemia in ICUs, as well as the mortality and economic impact. The participation of non-Candida albicans Candida species in the etiology of these infections is currently increasing.

Bacteremias: a leading cause of death

Bloodstream infections (BSIs), recognized to be a major cause of morbidity and mortality globally, are increasing in incidence. The reported rates of crude and attributable mortality vary, possibly due to heterogeneity in patient populations and methodology. Few studies, however, have focused on pathogen-specific attributable mortality. These studies include S. aureus, coagulase-negative staphylococci and enterococcus. Other studies of attributable mortality have been conducted in select populations such as nosocomial and community-acquired cohorts, intensive care units, neutropenic patients, and HIV-positive patients. Regrettably, despite advances in treatment and intensive care facilities, mortality remains high.

Infectious Complications of Cancer Therapy

Advances in the management of cancer, particularly the development of new chemotherapeutic agents, have greatly improved the survival and outcome of patients with hematologic malignancies and solid tumors; overall 5-year survival rates in cancer patients have improved from 39% in the 1960s to 60% in the 1990s.1 However, infection, caused by both the underlying malignancy and cancer chemotherapy, particularly myelosuppressive chemotherapy, remains a persistent challenge.

Epidemiological characteristics of nosocomial bloodstream infections and their causes

Background/Aim. Nosocomial bloodstream infections (BSI) contribute to grater morbidity and mortality rates, as well as to increasing length of hospital stay and health care costs. All patients with nosocomial BSI identified during the one-year period were studied to identify microbiological factors associated with these infections. Methods. A one-year prospective cohort study was performed in patients in intensive care units (ICU), and non- ICU patients. The patients were identified by active surveillance and positive blood cultures during the study period. The definitions of nosocomial BSI of the Center for Diseases Control and Prevention, Atlanta were used. Hospital laboratory detected growth in blood cultures, identified organisms, and performed susceptibility testing were in according with the American National Committee for Clinical Laboratory Standards. Results. The incidence of nosocomial BSI was 2.2 per 1 000 admission in non-ICU and 17.4 per 1 000 admission in ICU patients. The 28- day crude mortality rate was 44.9%. There were 60.3% primary nosocomial BSI. Gram-negative organisms accounted for 50%, gram-positive organisms accounted for 44.9%, and 4.1% were caused by fungi. The most common pathogens were coagulasenegative staphylococci (21.4%), Staphylococcus aureus (14.3%), Klebsiella spp. (13.3%), Pseudomonas aeruginosa (8.2%), Acinetobacter spp. (7.1%). Methicillin resistance was detected in 64.3% of S.aureus and 100% of coagulasa-negative staphylococci. Vancomycin resistance in enterococci and staphylococci was not deteced. The proportion of ceftazidim resistance among K.pneumoniae isolates was 92%. Conclusion. This study might help to better understanding not only the characteristics of BSI, but also the featares of their causes, primarily the resistance of coagulase-negative staphylococci and S. aureus to methicillin, and of K. pneumoniae to ceftazidime.

Evaluation of a rapid direct assay for identification of bacteria and the mec A and van genes from positive-testing blood cultures

We performed the first evaluation of a DNA strip assay (GenoType blood culture; Hain Lifescience, Nehren, Germany) for the detection of the most relevant bacterial sepsis pathogens directly from positive BACTEC blood culture bottles (Becton Dickinson, Heidelberg, Germany). The test comprises two panels, one for the direct species identification of important gram-positive cocci and the other for gram-negative rods. Additionally, detection of the mec A and the van genes are implemented. The GenoType assay was validated regarding its analytical sensitivity with blood cultures spiked with reference strains. Approximately 10(4) CFU per ml were detected. Analytical specificity was calculated with a test panel of 212 reference strains. Of the strains tested, 99% were correctly identified. Additionally, 279 consecutive blood cultures signaled positive by BACTEC were processed directly, in comparison to conventional methods. The GenoType assays were performed according to Gram stain morphology. A total of 243 (87.1%) of the 279 organisms isolated were covered by specific probes. A total of 152 organisms were gram-positive cocci, of which 148 (97.4%) were correctly identified by the GenoType assay. Ninety-one organisms were gram-negative rods, of which 89 (97.8%) were correctly identified. Concerning mec A gene detection, GenoType assay correctly detected 12 of 13 methicillin-resistant Staphylococcus aureus isolates. One Enterococcus faecium isolate with a positive van A gene isolated was correctly differentiated by the assay. All results were available 4 h after the results of microscopic analysis. The evaluated GenoType blood culture assay showed fast and reliable results in detecting the most important sepsis pathogens and the mec A and van genes directly from positive blood culture bottles.

Frequency of isolation and antimicrobial susceptibility of bacteria isolated from bloodstream infections at Children's Medical Center, Tehran, Iran, 1996–2000

Antimicrobial susceptibility patterns of major bloodstream pathogens from Iran provide essential information regarding the selection of antibiotic therapy for patients with bloodstream infections (BSIs) living in Iran. Unfortunately, data regarding the isolation frequency and antimicrobial susceptibility patterns of endemic BSI pathogens are scarce in Iran. To shed some light on the susceptibility patterns of BSI pathogens endemic to Tehran, Iran, we investigated the antimicrobial susceptibility patterns of 2248 bloodstream isolates from patients in Children's Medical Center (CMC) Hospital in Tehran between January 1996 and December 2000. Microbiology reports of 24600 blood specimens collected from inpatients in CMC Hospital were retrospectively reviewed. Specimen culture, bacterial identification and disk diffusion susceptibility testing were performed according to National Committee for Clinical Laboratory Standards guidelines. Overall, Gram-positive bacteria comprised 72% (1627/2248) of recovered isolates and Gram-negative bacteria comprised 28% (621/2248). Coagulase-negative staphylococci (CoNS) comprised 48.4% of all isolates, followed by Staphylococcus aureus (16.7%) and Klebsiella spp. (8.5%). Among the 621 Gram-negative organisms, Klebsiella spp. (31%) were the most frequently isolated, followed by Escherichia coli (21%) and Pseudomonas aeruginosa (17%). The rates of oxacillin resistance for S. aureus and CoNS isolates were similar (60% versus 61%); however, the rate of S. aureus vancomycin resistance was almost twice that of CoNS resistance (21% versus 11%). Over 55% of S. pneumoniae were resistant to penicillin and co-trimoxazole. Although all isolates of enterococci were susceptible to vancomycin, only 21% were susceptible to gentamicin. Among Gram-negative isolates, amikacin was shown to be very effective, with susceptibility rates of 84%. The susceptibility of Klebsiella spp. to ampicillin and co-trimoxazole was 1% and 39%, respectively. The susceptibility of Klebsiella spp., E. coli and Enterobacter spp. to ceftriaxone was 47%, 86% and 67%, respectively. There were notable differences in the order of the five most common organisms isolated from blood cultures, which can help set priorities for focused control efforts. Our findings highlight the importance of a nationwide surveillance programme to monitor the trends in isolation frequency of bacteria and their antimicrobial resistance patterns throughout Iran.

Comparison of the systemic inflammatory response syndrome between monomicrobial and polymicrobial Pseudomonas aeruginosa nosocomial bloodstream infections

Background

Some studies of nosocomial bloodstream infection (nBSI) have demonstrated a higher mortality for polymicrobial bacteremia when compared to monomicrobial nBSI. The purpose of this study was to compare differences in systemic inflammatory response and mortality between monomicrobial and polymicrobial nBSI with Pseudomonas aeruginosa.

Methods

We performed a historical cohort study on 98 adults with P. aeruginosa (Pa) nBSI. SIRS scores were determined 2 days prior to the first positive blood culture through 14 days afterwards. Monomicrobial (n = 77) and polymicrobial BSIs (n = 21) were compared.

Results

78.6% of BSIs were caused by monomicrobial P. aeruginosa infection (MPa) and 21.4% by polymicrobial P. aeruginosa infection (PPa). Median APACHE II score on the day of BSI was 22 for MPa and 23 for PPa BSIs. Septic shock occurred in 33.3% of PPa and in 39.0% of MPa (p = 0.64). Progression to septic shock was associated with death more frequently in PPa (OR 38.5, CI95 2.9–508.5) than MPa (OR 4.5, CI95 1.7–12.1). Maximal SIR (severe sepsis, septic shock or death) was seen on day 0 for PPa BSI vs. day 1 for MPa. No significant difference was noted in the incidence of organ failure, 7-day or overall mortality between the two groups. Univariate analysis revealed that APACHE II score ≥20 at BSI onset, Charlson weighted comorbidity index ≥3, burn injury and respiratory, cardiovascular, renal and hematologic failure were associated with death, while age, malignant disease, diabetes mellitus, hepatic failure, gastrointestinal complications, inappropriate antimicrobial therapy, infection with imipenem resistant P. aeruginosa and polymicrobial nBSI were not. Multivariate analysis revealed that hematologic failure (p < 0.001) and APACHE II score ≥20 at BSI onset (p = 0.005) independently predicted death.

Conclusion

In this historical cohort study of nBSI with P. aeruginosa, the incidence of septic shock and organ failure was high in both groups. Additionally, patients with PPa BSI were not more acutely ill, as judged by APACHE II score prior to blood culture positivity than those with MPa BSI. Using multivariable logistic regression analysis, the development of hematologic failure and APACHE II score ≥20 at BSI onset were independent predictors of death; however, PPa BSI was not.

Clinical trials of antifungal prophylaxis among patients undergoing surgery

Invasive mycoses have emerged as a major cause of morbidity and mortality. Epidemiological studies have shown that surgery services have the highest rate of Candida infections in the hospital. In addition to classical risk factors, heavy Candida colonization, recurrent gastrointestinal perforations, and acute pancreatitis are frequently associated with invasive candidiasis. Because prompt initiation of antifungal therapy is critical for cure but difficult to accomplish, prevention of fungal infections may play an important role in this clinical setting; however, few prophylactic or preemptive studies have been done to date. The choice, route of administration, and dose of the antifungal and comparator regimens and the use of clinically relevant and robust study end points are critical for the trial design. Various criteria have been used to identify patients at risk of candidiasis: surgical condition, presence of multiple risk factors, colonization indexes, or expected length of stay in the intensive care unit. Some are not selective enough, and others are time consuming and expensive. Rigorous selection of high-risk patients is crucial to optimize the risk-benefit ratio of preventive antifungal strategies. The aim is to maximize chances of reducing morbidity and mortality while minimizing treatment costs, exposure of low-risk patients to adverse events, and emergence of resistant fungal strains.

Recognition of Staphylococcus aureus by the innate immune system

The gram-positive bacterium Staphylococcus aureus is a major pathogen responsible for a variety of diseases ranging from minor skin infections to life-threatening conditions such as sepsis. Cell wall-associated and secreted proteins (e.g., protein A, hemolysins, and phenol-soluble modulin) and cell wall components (e.g., peptidoglycan and alanylated lipoteichoic acid) have been shown to be inflammatory, and these staphylococcal components may contribute to sepsis. On the host side, many host factors have been implicated in the innate detection of staphylococcal components. One class of pattern recognition molecules, Toll-like receptor 2, has been shown to function as the transmembrane component involved in the detection of staphylococcal lipoteichoic acid and phenol-soluble modulin and is involved in the synthesis of inflammatory cytokines by monocytes/macrophages in response to these components. Nod2 (nucleotide-binding oligomerization domain 2) is the intracellular sensor for muramyl dipeptide, the minimal bioactive structure of peptidoglycan, and it may contribute to the innate immune defense against S. aureus. The staphylococcal virulence factor protein A was recently shown to interact directly with tumor necrosis factor receptor 1 in airway epithelium and to reproduce the effects of tumor necrosis factor alpha. Finally, peptidoglycan recognition protein L is an amidase that inactivates the proinflammatory activities of peptidoglycan. However, peptidoglycan recognition protein L probably plays a minor role in the innate immune response to S. aureus. Thus, several innate immunity receptors may be implicated in host defense against S. aureus.

Comparison of fungal and nonfungal infections in a broad-based surgical patient population

BACKGROUND

Our aim was to compare fungal and nonfungal infections among a diverse surgical patient population.

METHODS

Data on all hospital-acquired infectious episodes among surgical intensive care unit and ward patients were collected prospectively over six years at a single university hospital. The relationships between fungal and nonfungal infection and over 100 variables were examined using univariate and multiple logistic regression analysis.

RESULTS

During the study period, 3,980 infectious episodes were identified; 554 were associated with fungal infection. Multiple logistic regression analysis demonstrated that markers of severity of acute illness (higher APACHE II scores and white blood cell counts, greater transfusion of cellular blood products, mechanical ventilator dependency, and prior infection) predicted fungal infection, whereas markers of chronic illness (comorbidities) did not independently predict either fungal or nonfungal infection. Patients with fungal infection were treated with more antibiotics for longer periods of time, had prolonged lengths of stay, and more often died compared with nonfungal infection patients. A separate multiple logistic regression analysis demonstrated that both fungal infection and the number of fungal sites of infection independently predicted mortality. Of all fungal isolates, only Candida albicans and Aspergillus spp. independently predicted mortality.

CONCLUSIONS

Fungal infections differ significantly in character and outcomes from nonfungal infections among surgical patients.

Profile and prognosis of febrile elderly patients with bacteremic urinary tract infection

OBJECTIVE

To describe the profile of elderly patients with bacteremic urinary tract infections (UTI) and correlate clinical and laboratory findings with the outcome in order to identify independent predictors of mortality.

METHODS

This retrospective study took place in a large community-based, geriatric hospital and included 191 patients aged 75-105 years with urine and blood cultures simultaneously positive for bacterial organisms. Records were analysed for demographic information, clinical and laboratory data over a 29 month period. Mortality was assessed and was correlated with these findings.

RESULTS

Most of the patients (80.1%) had community-acquired infection. Gram-negative organisms accounted for 87.6% of bacterial isolates, with Escherichia coli accounting for 46.1% of cases. Non-Escherichia coli Gram-negative organisms were highly resistant to two common urinary tract antibiotics (gentamicin and ceftriaxone). Patients with chronic urinary catheter had Gram-negative bacteria significantly less sensitive to ciprofloxacin, gentamycin, ampicillin and ceftriaxon than patients without catheter (p<0.05). In-hospital mortality was 33%. Multiple logistic regression analysis revealed that mortality was significantly related to the number of underlying diagnoses (p<0.0203), cognitive status (p<0.0003), length of hospitalization (p<0.0397), low level of serum albumin (p<0.0021), high neutrophil count (p<0.0001) and high level of lactate dehydrogenase (p<0.0351). Fatality was not associated with advanced age in the very old.

CONCLUSION

Bacteremic UTI in the elderly has a high mortality rate. In frail elderly patients with age-associated multiple severe underlying disorders and cognitive impairment, early recognition of bacteremic UTI and prompt, appropriate treatment are critical in reducing the mortality.

Initial management of candidemia at an academic medical center: Evaluation of the IDSA guidelines

Treatment of candidemia is more complicated because of the changing epidemiology of Candida and introduction of newer antifungal agents. Utilization and benefit of practice guidelines and infectious disease consultation for the management of candidemia has not been previously described in the routine clinical setting. We prospectively studied the impact of the Infectious Disease Society of America (IDSA) guidelines for the management of candidemia and infectious disease consultation on clinical outcomes in 119 patients with candidemia at a tertiary care hospital. Medical records were reviewed to capture data concerning use of antifungal agents, management of central venous catheters, and infectious disease consultation. Initial antifungal therapy was consistent with the IDSA guidelines in 76% of patients. Variation from the guidelines was independently associated with higher mortality (24% versus 57%, P = 0.003). Infectious disease consultation was independently associated with lower mortality (18% versus 39%, P < 0.01). Use of the IDSA guidelines and infectious disease consultation service was found to improve patient outcomes in patients with candidemia at our institution. Further studies should be performed to validate newer guidelines in a clinical setting at other institutions.

Épidémiologie des infections liées aux cathéters en réanimation

Catheter-related infections remain an important cause of nosocomial infection in the ICU. They include colonization of the device, exit-site infection and catheter-related bloodstream infection with or without bacteraemia. Data from clinical studies and surveillance networks should be compared cautiously due to important methodological differences and wide variations of device-utilization ratio between units or countries. In France, two regional networks (C-CLIN Paris-Nord and C-CLIN Sud-Est) produced comparable and reproducible results. Colonization represents five-six cases per 1000 catheter-days and bacteraemia represents one case per 1000 catheter-days. Incidence rates from North American studies are usually four to five times higher. Numerous risk factors have been identified. Some of them could be used to stratify patients according to risk of catheter-related infection and to allow more valid comparison between ICU's performances. Participation of French ICUs to the recent national surveillance networks (REA RAISIN and REACAT RAISIN) should be encouraged.

Faut-il faire des changements de cathéters sur guide ?

Two types of catheter replacement with the help of wire introducer are reported: systematic scheduled replacement and replacement in case of suspicion of catheter related infection. Guidelines do not recommend systematic scheduled replacement of the catheters. In case of suspicion of catheter infection, French consensus guidelines allow the use of wire introducer in the absence of local risk and of signs of severity. The American guidelines do not recommend the catheter change over guidewire in this setting.

Inactivation of transcription factor gene ACE2 in the fungal pathogen Candida glabrata results in hypervirulence

During an infection, the coordinated orchestration of many factors by the invading organism is required for disease to be initiated and to progress. The elucidation of the processes involved is critical to the development of a clear understanding of host-pathogen interactions. For Candida species, the inactivation of many fungal attributes has been shown to result in attenuation. Here we demonstrate that the Candida glabrata homolog of the Saccharomyces cerevisiae transcription factor gene ACE2 encodes a function that mediates virulence in a novel way. Inactivation of C. glabrata ACE2 does not result in attenuation but, conversely, in a strain that is hypervirulent in a murine model of invasive candidiasis. C. glabrata ace2 null mutants cause systemic infections characterized by fungal escape from the vasculature, tissue penetration, proliferation in vivo, and considerable overstimulation of the proinflammatory arm of the innate immune response. Compared to the case with wild-type fungi, mortality occurs much earlier in mice infected with C. glabrata ace2 cells, and furthermore, 200-fold lower doses are required to induce uniformly fatal infections. These data demonstrate that C. glabrata ACE2 encodes a function that plays a critical role in mediating the host-Candida interaction. It is the first virulence-moderating gene to be described for a Candida species.

Assessment of preemptive treatment to prevent severe candidiasis in critically ill surgical patients(*)

OBJECTIVE

To assess the efficacy of a preemptive antifungal therapy in preventing proven candidiasis in critically ill surgical patients.

DESIGN

Before/after intervention study, with 2-yr prospective and 2-yr historical control cohorts.

SETTING

Surgical intensive care unit (SICU) in a university-affiliated hospital.

PATIENTS

Nine hundred and thirty-three patients, 478 in the prospective group and 455 in the control group, with SICU stay > or =5 days.

INTERVENTIONS

During the prospective period, systematic mycological screening was performed on all patients admitted to the SICU, immediately at admittance and then weekly until discharge. A corrected colonization index was used to assess intensity of Candida mucosal colonization. Patients with corrected colonization index > or =0.4 received early preemptive antifungal therapy (fluconazole intravenously: loading dose 800 mg, then 400 mg/day for 2 wks).

MEASUREMENTS AND MAIN RESULTS

End points of this study were the frequency of proven candidiasis, especially SICU-acquired candidiasis. During the retrospective period, 32 patients of 455 (7%) presented with proven candidiasis: 22 (4.8%) were imported and 10 (2.2%) were SICU-acquired cases. During the prospective period, 96 patients with corrected colonization index > or =0.4 of 478 received preemptive antifungal treatment and only 18 cases (3.8%) of proven candidiasis were diagnosed; all were imported infections. Candida infections occurred more frequently in the control cohort (7% vs. 3.8%; p = .03). Incidence of SICU-acquired proven candidiasis significantly decreased from 2.2% to 0% (p < .001, Fisher test). Incidence of proven imported candidiasis remained unchanged (4.8% vs. 3.8%; p = .42). No emergence of azole-resistant Candida species (especially Candida glabrata, Candida krusei) was noted during the prospective period.

CONCLUSIONS

Targeted preemptive strategy may efficiently prevent acquisition of proven candidiasis in SICU patients. Further studies are being performed to assess cost-effectiveness of this strategy and its impact on selection of azole-resistant Candida strains on a long-term basis.

Nosocomial bloodstream infections in US hospitals: analysis of 24,179 cases from a prospective nationwide surveillance study

BACKGROUND

Nosocomial bloodstream infections (BSIs) are important causes of morbidity and mortality in the United States.

METHODS

Data from a nationwide, concurrent surveillance study (Surveillance and Control of Pathogens of Epidemiological Importance [SCOPE]) were used to examine the secular trends in the epidemiology and microbiology of nosocomial BSIs.

RESULTS

Our study detected 24,179 cases of nosocomial BSI in 49 US hospitals over a 7-year period from March 1995 through September 2002 (60 cases per 10,000 hospital admissions). Eighty-seven percent of BSIs were monomicrobial. Gram-positive organisms caused 65% of these BSIs, gram-negative organisms caused 25%, and fungi caused 9.5%. The crude mortality rate was 27%. The most-common organisms causing BSIs were coagulase-negative staphylococci (CoNS) (31% of isolates), Staphylococcus aureus (20%), enterococci (9%), and Candida species (9%). The mean interval between admission and infection was 13 days for infection with Escherichia coli, 16 days for S. aureus, 22 days for Candida species and Klebsiella species, 23 days for enterococci, and 26 days for Acinetobacter species. CoNS, Pseudomonas species, Enterobacter species, Serratia species, and Acinetobacter species were more likely to cause infections in patients in intensive care units (P<.001). In neutropenic patients, infections with Candida species, enterococci, and viridans group streptococci were significantly more common. The proportion of S. aureus isolates with methicillin resistance increased from 22% in 1995 to 57% in 2001 (P<.001, trend analysis). Vancomycin resistance was seen in 2% of Enterococcus faecalis isolates and in 60% of Enterococcus faecium isolates.

CONCLUSION

In this study, one of the largest multicenter studies performed to date, we found that the proportion of nosocomial BSIs due to antibiotic-resistant organisms is increasing in US hospitals.

Prevalence and antimicrobial susceptibilities of bacteria isolated from blood cultures of hospitalized patients in the United States in 2002

BACKGROUND

Bloodstream infections are associated with significant patient morbidity and mortality. Antimicrobial susceptibility patterns should guide the choice of empiric antimicrobial regimens for patients with bacteremia.

METHODS

From January to December of 2002, 82,569 bacterial blood culture isolates were reported to The Surveillance Network (TSN) Database-USA by 268 laboratories. Susceptibility to relevant antibiotic compounds was analyzed using National Committee for Clinical Laboratory Standards guidelines.

RESULTS

Coagulase-negative staphylococci (42.0%), Staphylococcus aureus (16.5%), Enterococcus faecalis (8.3%), Escherichia coli (7.2%), Klebsiella pneumoniae (3.6%), and Enterococcus faecium (3.5%) were the most frequently isolated bacteria from blood cultures, collectively accounting for >80% of isolates. In vitro susceptibility to expanded-spectrum beta-lactams such as ceftriaxone were high for oxacillin-susceptible coagulase-negative staphylococci (98.7%), oxacillin-susceptible S. aureus (99.8%), E. coli (97.3%), K. pneumoniae (93.3%), and Streptococcus pneumoniae (97.2%). Susceptibilities to fluoroquinolones were variable for K. pneumoniae (90.3-91.4%), E. coli (86.0-86.7%), oxacillin-susceptible S. aureus (84.0-89.4%), oxacillin-susceptible coagulase-negative staphylococci (72.7-82.7%), E. faecalis (52.1%), and E. faecium (11.3%). Combinations of antimicrobials are often prescribed as empiric therapy for bacteremia. Susceptibilities of all blood culture isolates to one or both agents in combinations of ceftriaxone, ceftazdime, cefepime, piperacillin-tazobactam or ciprofloxacin plus gentamicin were consistent (range, 74.8-76.3%) but lower than similar beta-lactam or ciprofloxacin combinations with vancomycin (range, 93.5-96.6%).

CONCLUSION

Ongoing surveillance for antimicrobial susceptibility remains essential, and will enhance efforts to identify resistance and attempt to limit its spread.

Are Antimicrobial-Impregnated Catheters Effective? Don't Throw Out the Baby with the Bathwater

The antimicrobial-impregnated central venous catheter (CVC) has been the most intensively studied technology for the prevention of CVC-related bloodstream infections (BSIs) over the past 30 years. Although more than a dozen randomized trials have shown significant benefit, authors of an analysis published in a recent issue of Clinical Infectious Diseases have raised questions about the efficacy of antimicrobial-impregnated CVCs because of perceived defects in the experimental design of the studies and statistical analyses of the data. They have further argued that even if this technology might be effective in preventing CVC-related BSI, its cost-effectiveness is questionable. Although most of the studies scrutinized by the authors of this analysis indeed had shortcomings, we believe that their analysis unjustifiably downplays a large body of research that has demonstrated a consistent reduction in CVC-related BSI and a clear-cut cost-effectiveness associated with the use of antimicrobial-impregnated CVCs.

Early detection and identification of commonly encountered Candida species from simulated blood cultures by using a real-time PCR-based assay

In a recent study, Candida species in clinical blood samples were detected using a real-time PCR-based method (Maaroufi et al, J Clin Microbiol 2003, 41:3293-3298). For the present study, we evaluated the efficiency of this method as an adjunct to the BACTEC blood culture system to early detection of positivity and negativity of simulated low candidemias. We first established an in vitro correlation between the inoculum of the most frequently encountered Candida species and the time to positivity of these microorganisms. Then, aliquots from blood culture bottles infected with a final average candidal inoculum of 3.18 colony-forming units (CFU)/culture bottle (range, 1 to 6 CFU) were collected at increasing incubation times, and DNA was extracted and submitted to the TaqMan-based PCR assay. To optimize this assay, we evaluated the effect of adding 0.5% bovine serum albumin (BSA) to DNA extracts and found that it decreased the effects of inhibitors. Using specific probes for the tested Candida species, the PCR assay was positive on blood culture aliquots collected from the BACTEC system after a minimum culture turnaround time (TAT) of 3.11 +/- 1.24 hours. Addition of BSA to PCR reaction mixtures improves the TAT (1.84 +/- 0.41 hours). Hence, the combination of DNA "amplification" in the culture bottles by normal growth with an additional DNA amplification by PCR might be a reliable tool facilitating the early diagnosis of low candidemias.

Prevention of intravascular catheter-related infection with newer chlorhexidine-silver sulfadiazine-coated catheters: a randomized controlled trial

BACKGROUND

The indication of antiseptic-coated catheters remains debated.

OBJECTIVE

To test the ability of the new generation of chlorhexidine-silver and sulfadiazine-coated catheters, with enhanced antiseptic coating, to reduce the risk of central venous catheter (CVC)-related infection in ICU patients.

DESIGN

Multicentre randomized double-blind trial.

PATIENTS AND SETTING

A total of 397 patients from 14 ICUs of university hospitals in France.

INTERVENTION

Patients were randomized to receive an antiseptic-coated catheter (ACC) or a standard non-coated catheter (NCC).

MEASUREMENTS

Incidence of CVC-related infection.

RESULTS

Of 367 patients having a successful catheter insertion, 363 were analysed (175 NCC and 188 ACC). Patients had one (NCC=162, ACC=180) or more (NCC=13, ACC=11) CVC inserted. The two groups were similar for insertion site [subclavian (64 vs 69)] or jugular (36 vs 31%)], and type of catheters (single-lumen 18 vs 18%; double-lumen 82 vs 82%), and mean (median) duration of catheterisation [12.0+/-11.7 (9) vs 10.5+/-8.8 (8) days in the NCC and ACC groups, respectively]. Significant colonisation of the catheter occurred in 23 (13.1%) and 7 (3.7%) patients, respectively, in the NCC and ACC groups (11 vs 3.6 per 1000 catheter-days; p=0.01); CVC-related infection (bloodstream infection) occurred in 10 (5) and 4 (3) patients in the NCC and CC groups, respectively (5.2 vs 2 per 1000 catheter days; p=0.10).

CONCLUSIONS

In the context of a low baseline infection rate, ACC were associated with a significant reduction of catheter colonisation and a trend to reduction of infection episodes, but not of bloodstream infection.

Bloodstream infections caused by Staphylococcus aureus in a university hospital in Turkey: clinical and molecular epidemiology of methicillin-resistant Staphylococcus aureus

In total, 177 patients with bloodstream infections caused by Staphylococcus aureus (BSISA) were investigated prospectively between June 1999 and June 2001. Of these, 19.8% had community-acquired BSISA, while 80.2% had nosocomial BSISA. Surgical intervention, foreign body, mechanical ventilation, total parenteral nutrition, and previous antibiotic treatment were found to be important risk factors for the nosocomial BSISA group. Secondary BSISA formed a greater proportion (62.9%) of community-acquired infections than of nosocomial infections (26.8%; p 0.0001). Catheter-related nosocomial BSISA was observed in 72.1% of patients. The suppurative complication rate was significantly higher among community-acquired infections (22.9%) than among nosocomial infections (6.3%; p 0.008). Of the nosocomial BSISA, 65.5% were methicillin-resistant. Analysis of 80 methicillin-resistant S. aureus isolates by pulsed-field gel electrophoresis identified ten main clones (A-J), but 61 (76.3%) of the 80 isolates belonged to clone A.

Antibiotics delay but do not prevent bacteremia and lung injury in murine sepsis

OBJECTIVES

To investigate the effect of antibiotics on infection, lung injury, and mortality rate in polymicrobial sepsis and to determine whether an association exists between infection and lung injury and mortality rate. To circumvent the effect of antibiotics on cultures, we used polymerase chain reaction to detect bacteria.

DESIGN

Prospective, randomized, controlled laboratory trial.

SETTING

University research laboratory.

SUBJECTS

C57/BL6 mice.

INTERVENTIONS

Mice underwent cecal ligation and puncture without antibiotics (CLP) or with imipenem (CLP + Abx).

MEASUREMENTS AND MAIN RESULTS

CLP resulted in 50% mortality rate at 48 hrs and 100% mortality rate at 84 hrs. Antibiotics delayed these time points to 72 and 120 hrs, respectively. Lung injury occurred before mortality in both groups. Polymerase chain reaction detected bacteria in the blood and lungs of all CLP mice by 24 hrs. Antibiotics delayed but did not prevent infection in CLP + Abx mice. Serum tumor necrosis factor-alpha and lung endotoxin were elevated to similar concentrations in both CLP and CLP + Abx mice.

CONCLUSIONS

In this model of sepsis, antibiotics delay but do not prevent acute lung injury and mortality. Even in the presence of antibiotics, acute lung injury is strongly associated with bacteremia and bacteria within the lungs.

Burden of hospitalization of patients with Candida and Aspergillus infections in Australia

OBJECTIVES

This study examined the burden of hospitalization of patients with Aspergillus and Candida infections in Australia from 1995 to 1999.

METHODS

Data were extracted from the National Hospital Morbidity Database. A hospitalization with an aspergillosis diagnosis was defined as any discharge with a diagnosis of aspergillosis. A hospitalization with a candidiasis diagnosis was defined as any discharge with a diagnosis of disseminated, invasive, or non-invasive candidiasis. Outcome measures included number of hospitalizations, length of stay (LOS), cost (AUS$), and mortality.

RESULTS

4583 hospitalizations with an aspergillosis diagnosis and 57,758 hospitalizations with a candidiasis diagnosis were identified. These hospitalizations were associated with a total of 813,398 hospital days, AUS$563 million in cost, and 4967 in-hospital deaths during the study period. The mean LOS for a hospitalization with an aspergillosis diagnosis was 12 days, cost AUS$9,334, and was associated with 8% mortality. For disseminated, invasive, and non-invasive candidiasis, the respective mean LOS were 31, 17, and 12 days; costs were AUS$33,274, AUS$12,954, and AUS$7,694; and mortality was 26%, 9%, and 8%.

CONCLUSIONS

Hospitalizations with diagnoses for fungal infections were associated with lengthy hospital stays, high costs, and high mortality.

Epidemiology of candidemia in Swiss tertiary care hospitals: secular trends, 1991-2000

Candida species are among the most common bloodstream pathogens in the United States, where the emergence of azole-resistant Candida glabrata and Candida krusei are major concerns. Recent comprehensive longitudinal data from Europe are lacking. We conducted a nationwide survey of candidemia during 1991-2000 in 17 university and university-affiliated hospitals representing 79% of all tertiary care hospital beds in Switzerland. The number of transplantations and bloodstream infections increased significantly (P<.001). A total of 1137 episodes of candidemia were observed: Candida species ranked seventh among etiologic agents (2.9% of all bloodstream isolates). The incidence of candidemia was stable over a 10-year period. C. albicans remained the predominant Candida species recovered (66%), followed by C. glabrata (15%). Candida tropicalis emerged (9%), the incidence of Candida parapsilosis decreased (1%), and recovery of C. krusei remained rare (2%). Fluconazole consumption increased significantly (P<.001). Despite increasing high-risk activities, the incidence of candidemia remained unchanged, and no shift to resistant species occurred.

Epidemiology of Candida species infections in critically ill non-immunosuppressed patients

A substantial proportion of patients become colonised with Candida spp during hospital stay, but only few subsequently develop severe infection. Clinical signs of severe infection manifest early but lack specificity until late in the course of the disease, thus representing a particular challenge for diagnosis. Mostly nosocomial, invasive candidiasis occurs in only 1-8% of patients admitted to hospitals, but in around 10% of patients housed in intensive care units where it can represent up to 15% of all nosocomial infections. We review the epidemiology of invasive candidiasis in non-immunocompromised, critically ill patients with special emphasis on disease trends over time, pathophysiology, diagnostic approach, risk factors, and impact. Recent epidemiological data suggesting that the emergence of non-albicans candida strains with reduced susceptibility to azoles, previously linked to the use of new antifungals for empiric and prophylactic therapy in immunocompromised patients, may not have occurred in the critically ill. Management of invasive candidiasis in these patients will be addressed in the December issue of The Lancet Infectious Diseases.

Attributable Mortality of Nosocomial Candidemia, Revisited

We reexamined the attributable mortality of nosocomial candidemia 15 years after a retrospective cohort study performed at our hospital demonstrated an attributable mortality of 38%. For all episodes of nosocomial candidemia between 1 July 1997 and 30 June 2001, we matched control patients with case patients by age, sex, date of hospital admission, underlying disease(s), length of time at risk, and surgical procedure(s). We analyzed 108 matched pairs. There were no statistically significant differences in age, sex, underlying disease(s), time at risk, surgical procedure, or vital signs at admission between cases and controls. The crude mortality among case patients was 61% (66 of 108 patients), compared with 12% (13 of 108) among control patients, for an attributable mortality of 49% (95% CI, 38%-60%). Nosocomial candidemia is still associated with an extremely high crude and attributable mortality--much higher than that expected from underlying disease alone.

Use of parenteral colistin for the treatment of serious infection due to antimicrobial-resistant Pseudomonas aeruginosa

Serious infection due to strains of Pseudomonas aeruginosa that exhibit resistance to all common antipseudomonal antimicrobials increasingly is a serious problem. Colistin was used as salvage therapy for 23 critically ill patients with multidrug-resistant P. aeruginosa infection. Twenty-two patients who had septic shock (n=14) and/or renal failure (n=21) received mechanical ventilatory support at baseline. The most common types of infection were pneumonia (n=18) and intra-abdominal infection (n=5). Colistin was administered for a median of 17 days (range, 7-36 days). Seven patients died during therapy, at a median of 17 days (range, 4-26 days) after initiation of treatment. A favorable clinical response was observed in 14 patients (61%); only 3 patients experienced relapse. Bacteremia was the only significant factor associated with treatment failure (P=.02). One patient manifested diffuse weakness that resolved after temporary cessation of colistin therapy. Colistin provides an important salvage therapeutic option for patients with otherwise untreatable serious P. aeruginosa infection.

Candidemia in critically ill patients: difference of outcome between medical and surgical patients

OBJECTIVE

Candidemia is increasingly encountered in critically ill patients with a high fatality rate. The available data in the critically ill suggest that patients with prior surgery are at a higher risk than others. However, little is known about candidemia in medical settings. The main goal of this study was to compare features of candidemia in critically ill medical and surgical patients.

DESIGN

Ten-year retrospective cohort study (1990-2000).

SETTING

Medical and surgical intensive care units (ICUs) of a teaching hospital.

PATIENTS

Fifty-one patients with at least one positive blood culture for Candida species.

MAIN RESULTS

Risk factors were retrieved in all of the patients: central venous catheter (92.1%), mechanical ventilation (72.5%), prior bacterial infection (70.6%), high fungal colonization index (45.6%). Candida albicans accounts for 55% of all candidemia. The overall mortality was 60.8% (85% and 45.2% in medical and surgical patients, respectively). Independent factors associated with survival were prior surgery (hazard ratio [HR] =0.25; 0.09-0.67 95% confidence interval [CI], p<0.05), antifungal treatment (HR =0.11; 0.04-0.30 95% CI, p<0.05) and absence of neutropenia (HR =0.10; 0.02-0.45 95% CI, p<0.05). Steroids, neutropenia and high density of fungal colonization were more frequently found among medical patients compared to surgical ones.

CONCLUSIONS

Candidemia occurrence is associated with a high mortality rate among critically ill patients. Differences in underlying conditions could account for the poorer outcome of the medical patients. Screening for fungal colonization could allow identification of such high-risk patients and, in turn, improve outcome.

Candidemia in Finland, 1995-1999

We analyzed laboratory-based surveillance candidemia data from the National Infectious Disease Register in Finland and reviewed cases of candidemia from one tertiary-care hospital from 1995 to 1999. A total of 479 candidemia cases were reported to the Register. The annual incidence rose from 1.7 per 100,000 population in 1995 to 2.2 in 1999. Species other than Candida albicans accounted for 30% of cases without change in the proportion. A total of 79 cases of candidemia were identified at the hospital; the rate varied from 0.03 to 0.05 per 1,000 patient-days by year. Predisposing factors included indwelling catheters (81%), gastrointestinal surgery (27%), hematologic malignancy (25%), other types of surgery (21%), and solid malignancies (20%). Crude 7-day and 30-day case-fatality ratios were 15% and 35%, respectively. The rate of candidemia increased in Finland but is still substantially lower than in the United States. No shift to non-C. albicans species could be detected.

Epidemiology and outcome of nosocomial and community-onset bloodstream infection

We performed a prospective study of bloodstream infection to determine factors independently associated with mortality. Between February 1999 and July 2000, 929 consecutive episodes of bloodstream infection at two tertiary care centers were studied. An ICD-9-based Charlson Index was used to adjust for underlying illness. Crude mortality was 24% (14% for community-onset versus 34% for nosocomial bloodstream infections). Mortality attributed to the bloodstream infection was 17% overall (10% for community-onset versus 23% for nosocomial bloodstream infections). Multivariate logistic regression revealed the independent associations with in-hospital mortality to be as follows: nosocomial acquisition (odds ratio [OR] 2.6, P < 0.0001), hypotension (OR 2.6, P < 0.0001), absence of a febrile response (P = 0.003), tachypnea (OR 1.9, P = 0.001), leukopenia or leukocytosis (total white blood cell count of <4500 or >20000, P = 0.003), presence of a central venous catheter (OR 2.0, P = 0.0002), and presence of anaerobic organism (OR 2.5, P = 0.04). Even after adjustments were made for underlying illness and length of stay, nosocomial status of bloodstream infection was strongly associated with increased total hospital charges (P < 0.0001). Although accounting for about half of all bloodstream infections, nosocomial bloodstream infections account for most of the mortality and costs associated with bloodstream infection.

Nosocomial bloodstream infections in pediatric patients in United States hospitals: epidemiology, clinical features and susceptibilities

BACKGROUND

We identified the predominant pathogens and antimicrobial susceptibilities of nosocomial bloodstream isolates in pediatric patients in the US Prospective surveillance for nosocomial bloodstream infections at 49 hospitals during a 6-year period [Surveillance and Control of Pathogens of Epidemiologic Importance (SCOPE)] detected 22 609 bloodstream infections, of which 3432 occurred in patients < or =16 years of age.

RESULTS

Gram-positive organisms accounted for 65% of cases, Gram-negative organisms accounted for 24% of cases and 11% were caused by fungi. The overall crude mortality was 14% (475 of 3432) but notably higher for infections caused by Candida spp. and Pseudomonas aeruginosa, 20 and 29%, respectively. The most common organisms were coagulase-negative staphylococci (43%), enterococci, Staphylococcus aureus and Candida spp. (each, 9%). The mean interval between admission and infection averaged 21 days for coagulase-negative staphylococci, 25 days for S. aureus and Candida spp., 32 days for Klebsiella spp. and 34 days for Enterococcus spp. The proportion of methicillin-resistant S. aureus increased from 10% in 1995 to 29% in 2001. Vancomycin-resistance was seen in 1% of Enterococcus faecalis and in 11% of Enterococcus faecium isolates.

CONCLUSION

Nosocomial BSI occurred predominantly in very young and/or critically ill children. Gram-positive pathogens predominated across all ages, and increasing antimicrobial resistance was observed in pediatric patients.

Do antimicrobial-impregnated central venous catheters prevent catheter-related bloodstream infection?

Controversy surrounds the role of central venous catheters (CVCs) impregnated with antimicrobial agents in the prevention of catheter-related bloodstream infection (CRBSI). We reviewed the current literature to evaluate the efficacy of antimicrobial-impregnated CVCs for preventing CRBSI. Eleven randomized studies published in article form were identified that included a control group that received nonimpregnated CVCs. We evaluated study methodologies, inclusion of key patient characteristics, use of clinically relevant end points, and molecular-relatedness studies. Review of these 11 trials revealed several methodological flaws, including inconsistent definitions of CRBSI, failure to account for confounding variables, suboptimal statistical and epidemiological methods, and rare use of clinically relevant end points. This review also failed to demonstrate any significant clinical benefit associated with the use of antimicrobial-impregnated CVCs for the purpose of reducing CRBSI or improving patient outcomes. More rigorous studies are required to support or refute the hypothesis that antimicrobial-impregnated CVCs reduce the rate of or prevent CRBSI.

Effects of rapid detection of bloodstream infections on length of hospitalization and hospital charges

Current automated continuous-monitoring blood culture systems afford more rapid detection of bacteremia and fungemia than is possible with non-instrument-based manual methods. Use of these systems has not been studied objectively with respect to impact on patient outcomes, including hospital charges and length of hospitalization. We conducted a prospective, two-center study in which the time from the obtainment of the initial positive blood culture until the Gram stain was called was evaluated for 917 cases of bloodstream infection. Factors showing univariate associations with a shorter time to notification included higher body temperature and respiratory rate and higher percentage of immature neutrophils. Multiple linear regression models determined that the primary predictors of both increased microbiology laboratory and total hospital charges for patients with bloodstream infection were nonmicrobiologic and included length of stay and host factors such as the admitting service and underlying illness score. Significant microbiologic predictors of increased charges included the number of blood cultures obtained, nosocomial acquisition, and polymicrobial bloodstream infections. Accelerated failure time regression analysis demonstrated that microbiologic factors, including time until notification, organism group, and nosocomial acquisition, were independently associated with length of hospitalization after bacteremia, as were the factors of admitting service, gender, and age. Our data suggest that an increased time to notification of bloodstream infection is independently associated with increased length of stay. We conclude that the time to notification is an obvious target for efforts to shorten length of stay. The newest generation of automated continuous-monitoring blood culture systems, which shorten the time required to obtain a positive result, should impact length of hospitalization.

Influence of systemic inflammatory response syndrome and sepsis on outcome of critically ill infected patients

The clinical significance of the systemic inflammatory response in infected patients remains unclear. We examined risk factors for hospital mortality in 3,608 intensive care unit patients included in the European Sepsis Study. Patients were categorized as having infection without or with (i.e., sepsis) systemic inflammatory response, severe sepsis, and septic shock, on the first day of infection. Hospital mortality varied from 25 to 60% according to sepsis stage, but did not differ between the first two categories (hazard ratio, 0.94; p = 0.55), whereas there was a grading of severity from sepsis to severe sepsis (1.53, p < 10-4) and septic shock (2.64, p < 10-4). Within each stage, mortality was unaffected by the number of inflammatory response criteria. Prognostic factors identified by Cox regression included comorbid conditions, severity of acute illness and acute organ dysfunction, shock, nosocomial infection, and infection caused by aerobic gram-negative bacilli, enterobacteria, Staphylococcus aureus, and infection from a digestive or unknown source. We conclude that whereas the categorization of infection by the presence of organ dysfunction or shock has strong prognostic significance, infection and sepsis have similar outcomes, unaffected by the presence or number of inflammatory response criteria. Refinement of risk stratification of patients presenting with infection and no organ dysfunction is needed.

Current trends in the epidemiology of nosocomial bloodstream infections in patients with hematological malignancies and solid neoplasms in hospitals in the United States

A total of 2340 patients with underlying malignancy were identified among 22,631 episodes of nosocomial bloodstream infections (BSIs) in a prospectively collected database for 49 hospitals in the United States (Surveillance and Control of Pathogens of Epidemiologic Importance [SCOPE] Project). Data were obtained for the period of March 1995 through February 2001. Gram-positive organisms accounted for 62% of all BSIs in 1995 and for 76% in 2000 (P<.001), and gram-negative organisms accounted for 22% and 14% of all BSIs for these years, respectively. Neutropenia was observed in 30% of patients, so neutropenic and nonneutropenic patients were compared. In both, the predominant pathogens were coagulase-negative staphylococci (32% of isolates recovered from neutropenic patients and 30% of isolates recovered from nonneutropenic patients). The source of BSI was not determined for 57% of patients. The crude mortality rate was 36% for neutropenic patients and 31% for nonneutropenic patients.

Evaluation of outcome in critically ill patients with nosocomial enterobacter bacteremia: results of a matched cohort study

STUDY OBJECTIVE

To evaluate the clinical impact of nosocomial Enterobacter bacteremia in critically ill patients.

DESIGN

Retrospective (January 1992 to December 2000) matched cohort study.

SETTING

Fifty-four-bed ICU (including medical, surgical, cardiosurgical ICU, and burns unit) from a university hospital.

PATIENTS

Sixty-seven ICU patients with Enterobacter bacteremia (case patients) and 134 control patients.

INTERVENTION

Matching of control patients (1:2 ratio) was on the basis of the APACHE (acute physiology and chronic health evaluation) II system. As expected, mortality can be derived from this severity-of-disease classification system; this matching procedure results in an equal expected mortality rate for patients with Enterobacter bacteremia and control patients.

RESULTS

The overall rate of appropriate antibiotic therapy in patients with Enterobacter bacteremia was high (96%) and initiated soon after the onset of the bacteremia (0.5 +/- 0.9 days). Patients with Enterobacter bacteremia had more hemodynamic instability (p = 0.015), longer ICU stay (p < 0.001), and ventilator dependence (p < 0.001). No differences between case and control patients were found in age (52 years vs 53 years, p = 0.831), prevalence of acute renal failure (16% vs 16%, p = 0.892), and acute respiratory failure (93% vs 84%, respectively; p = 0.079). In-hospital mortality rates for case and control patients were not different (34% vs 39%, respectively; p = 0.536).

CONCLUSION

After accurate adjustment for severity of underlying disease and acute illness, no difference was found between ICU patients with Enterobacter bacteremia and matched control patients. In the presence of fast and appropriate antibiotic therapy, Enterobacter bacteremia does not adversely affect the outcome in ICU patients.

Secular trends of candidemia over 12 years in adult patients at a tertiary care hospital

The incidence of fungal infections has been increasing for the last 3 decades, especially among neutropenic, cancer, and critically ill patients. These infections are associated with high mortality rates. We retrospectively reviewed medical charts of adult patients with fungemia from 1989 to 2000 at our institution. The characteristics of the population groups served by the hospital were described. Of 328 patients with fungemia, we reviewed 315 (96%) medical records, and focused on those with candidemia (n = 294). The species distribution in patients with candidemia showed that the most commonly identified species were Candida albicans (66%), followed by C. glabrata (17%), and C. parapsilosis (6%). The incidence of candidemia ranged from 0.2 to 0.46 per 10,000 patient-days with the highest incidence in 1993 and the lowest in 1997. Although most studies show an increased incidence of candidemia, we observed a reduction over the study period. Furthermore, we observed no shift from C. albicans to non-albicans Candida species despite a significant increase in the use of fluconazole. The overall mortality among patients with candidemia was 44%, with the highest rate in patients over 65 years (52%). Factors independently associated with higher mortality were patient age greater than 65 years, intensive care unit admission, and underlying cancer.

Prospective, multicenter surveillance study of Candida glabrata: fluconazole and itraconazole susceptibility profiles in bloodstream, invasive, and colonizing strains and differences between isolates from three urban teaching hospitals in New York City (Candida Susceptibility Trends Study, 1998 to 1999)

Since the 1990s, the substantial increase in the rate of Candida glabrata infections has become a serious problem. As most C. glabrata infections arise from the host's endogenous microflora, the present prospective, multicenter analysis included all clinical isolates associated with colonization and with systemic and hematogenous candidiasis. Among 347 C. glabrata isolates, the overall rates of resistance to fluconazole (MIC > or = 64 micro g/ml) and itraconazole (MIC > or = 1 micro g/ml) were 10.7 and 15.2%, respectively, although for half (n = 148) of the itraconazole-susceptible isolates the MICs (0.25 to 0.5 micro g/ml) were in the susceptible-dependent upon dose range. Fluconazole resistance was more common among C. glabrata isolates obtained from centers caring for patients with cancer (MICs at which 90% of isolates are inhibited [MIC(90)s] = 32 micro g/ml) or AIDS (MIC(90)s > 64 micro g/ml) than among C. glabrata isolates from a community-based university medical center (MIC(90)s = 16 micro g/ml) (P = 0.001). Thirty-three bloodstream isolates and those obtained from other body sites had similar in vitro susceptibility profiles. The fluconazole MIC(90)s (< or =16 micro g/ml) for C. glabrata yeast isolates from the gastrointestinal tract were lower than those (> or =64 micro g/ml) for C. glabrata isolates from respiratory and urinary tract samples (P = 0.01). A similar discrepancy for itraconazole was not significant (P > 0.5). We did not observe differences in fluconazole or itraconazole susceptibility profiles among C. glabrata isolates associated with either hematogenous dissemination or colonization. The significant discrepancy in antifungal susceptibility among C. glabrata organisms isolated from hospitals in the same geographic region emphasizes the significance of periodic susceptibility surveillance programs for individual institutions, especially those providing care to patients at risk.

Systemic candidiasis in intensive care units: A multicenter, matched-cohort study

OBJECTIVE

To determine the impact of systemic candidiasis on the mortality and length of hospital stay of intensive care unit (ICU) patients and the associated workload.

DESIGN

Multicenter, retrospective, matched-cohort study.

SETTING

Data were retrieved from a computerized database that prospectively collected clinical data submitted by 32 ICUs in the Paris, France area.

PATIENTS

A total of 149 stays with systemic candidiasis, including 104 candidemia, on ICU admission were identified in a 3-year period (1995-1997) among 49,063 admissions (3 per 1,000 admission). A total of 121 cases were matched with patients with no evidence of systemic Candida infection during the hospitalization period under study (same ICU, date of ICU admission, age, sex, simplified acute physiology score (SAPS II), location of the patient before admission, type of admission).

RESULTS

Patients with systemic candidiasis had longer ICU length of stays than controls (25 vs 10 d; P =.001) with a relative risk for death of 2.27 (95% confidence interval, 1.64-3.11; P =.001). There was no difference between patients with systemic candidiasis with or without positive blood culture.

CONCLUSIONS

Systemic Candida infections increased mortality and morbidity in severely ill patients. Optimizing management of such infections is imperative.

Candidemia as a cause of septic shock and multiple organ failure in nonimmunocompromised patients

OBJECTIVE

To describe outcomes of septic shock and multiple organ failure arising from candidemia.

DESIGN

Secondary cohort analysis of data from the placebo arm of the North American Septic Shock Trial (NORASEPT II), the largest prospective, randomized, double-blind, controlled multiple center study of septic shock conducted to date, with predetermined end point analysis of outcomes.

SETTING

Adult intensive care units in 105 hospitals in the United States and Canada.

SUBJECTS

A cohort of ten purely candidemic patients in septic shock were compared with a cohort of 376 purely bacteremic patients in septic shock. Patients were not immunocompromised, because patients on corticosteroids, with neutropenia, or posttransplantation were excluded from enrollment in NORASEPT II.

MEASUREMENTS AND MAIN RESULTS

Demographic variables, baseline characteristics, 28-day mortality rates, and multiple organ failure were compared for the two cohorts. Candidemic patients were more likely to have a history of underlying renal failure at baseline and to require dialysis at onset of septic shock. Both causes of septic shock are associated with an extremely high severity of illness (Acute Physiology and Chronic Health Evaluation II: candidemic septic shock, 32 +/- 10; bacteremic septic shock, 30 +/- 8; p =.44). More than 70% of patients with candidemia and septic shock were in multiple organ failure at days 3, 7, and 14; patients with candidemic septic shock sustained persistent multiple organ failure and showed delayed recovery from multiple organ failure compared with patients with bacteremic septic shock. Mortality rate at 28 days was 60% in candidemic septic shock and 46% in bacteremic septic shock (p =.38).

CONCLUSIONS

Candidemia with septic shock is infrequent in nonimmunocompromised patients but has a very high mortality rate, a high likelihood of associated multiple organ failure, and possibly a delayed recovery from multiple organ failure. Patients with candidemic septic shock are more likely to have underlying renal failure at baseline.

Nosocomial bloodstream infections in Finnish hospitals during 1999-2000

Prospective laboratory-based surveillance in 4 Finnish hospitals during 1999-2000 identified 1477 cases of nosocomial bloodstream infection (BSI), with an overall rate of 0.8 BSIs per 1000 patient-days. Of BSI cases, 33% were in patients with a hematological malignancy and 15% were in patients with a solid malignancy; 26% were in patients who had undergone surgery preceding infection. Twenty-six percent of BSIs were related to intensive care, and 61% occurred in patients with a central venous catheter. Sixty-five percent of the 1621 causative organisms were gram positive, 31% were gram negative, and 4% were fungi. The most common pathogens were coagulase-negative staphylococci (31%), Escherichia coli (11%), Staphylococcus aureus (11%), and enterococci (6%). Methicillin resistance was detected in 1% of S. aureus isolates and vancomycin resistance in 1% of enterococci. The 7-day case-fatality ratio was 9% and was highest for infections caused by Candida (21%) and enterococci (18%). The overall rate of nosocomial BSIs was similar to rates in England and the United States, but S. aureus, enterococci, and fungi were less common in our study, and the prevalence of antibiotic resistance was lower.

Complications of central venous catheters: internal jugular versus subclavian access--a systematic review

OBJECTIVE

To test whether complications happen more often with the internal jugular or the subclavian central venous approach.

DATA SOURCE

Systematic search (MEDLINE, Cochrane Library, EMBASE, bibliographies) up to June 30, 2000, with no language restriction.

STUDY SELECTION

Reports on prospective comparisons of internal jugular vs. subclavian catheter insertion, with dichotomous data on complications.

DATA EXTRACTION

No valid randomized trials were found. Seventeen prospective comparative trials with data on 2,085 jugular and 2,428 subclavian catheters were analyzed. Meta-analyses were performed with relative risk (RR) and 95% confidence interval (CI), using fixed and random effects models.

DATA SYNTHESIS

In six trials (2,010 catheters), there were significantly more arterial punctures with jugular catheters compared with subclavian (3.0% vs. 0.5%, RR 4.70 [95% CI, 2.05-10.77]). In six trials (1,299 catheters), there were significantly less malpositions with the jugular access (5.3% vs. 9.3%, RR 0.66 [0.44-0.99]). In three trials (707 catheters), the incidence of bloodstream infection was 8.6% with the jugular access and 4.0% with the subclavian access (RR 2.24 [0.62-8.09]). In ten trials (3,420 catheters), the incidence of hemato- or pneumothorax was 1.3% vs. 1.5% (RR 0.76 [0.43--1.33]). In four trials (899), the incidence of vessel occlusion was 0% vs. 1.2% (RR 0.29 [0.07-1.33]).

CONCLUSIONS

There are more arterial punctures but less catheter malpositions with the internal jugular compared with the subclavian access. There is no evidence of any difference in the incidence of hemato- or pneumothorax and vessel occlusion. Data on bloodstream infection are scarce. These data are from nonrandomized studies; selection bias cannot be ruled out. In terms of risk, the data most likely represent a best case scenario. For rational decision-making, randomized trials are needed.

Therapeutic dilemma of fluconazole prophylaxis in intensive care

OBJECTIVE

To review the data concerning the use of prophylactic fluconazole in intensive care patients who are not immunocompromised.

DATA SOURCE

Literature identified through MEDLINE (1966-March 2001) and recent abstracts of data presented at scientific meetings.

DATA SYNTHESIS

The use of fluconazole as a prophylactic antifungal agent is well documented in patients who are immunocompromised or undergoing bone marrow or solid organ transplantation, with supportive results. Recently published data suggest that the use of fluconazole in high-risk surgical patients can be safe and effective for preventing certain candida infections. However, there is growing evidence that the use of fluconazole may be contributing to the higher prevalence of fluconazole-resistant fungal infections.

CONCLUSIONS

The use of prophylactic fluconazole in nonneutropenic patients is controversial. Retrospective and surveillance studies of nosocomial fungal infections suggest that the use of fluconazole may be contributing to the shift in fungal flora causing these infections and that the isolates are more fluconazole resistant. Fluconazole prophylaxis in surgical patients may be justified in patients who are at the greatest risk of developing fungal infections, those requiring multiple intraabdominal surgeries, or those with recurrent gastrointestinal perforations or anastomotic leakages, but there is a lack of randomized controlled trials to recommend its widespread use at this time.

The Role of Intravascular Devices in Sepsis

Intravascular devices (IVDs) are widely used in modern day health care. Unfortunately, their use is associated with substantial risk of bloodstream infection (BSI) and sepsis, with increased hospitalization and hospital mortality. IVDs are the most common cause of nosocomial BSI. The wider use of new methodologies for diagnosis of IVD-related infection should allow earlier and more focused therapy and, especially, improve the accuracy of surveillance. Of all nosocomial infections, IVD-related BSIs are most amendable to prevention.