Management of invasive candidiasis in critically ill patients

Candida species have become predominant pathogens in critically ill patients. In this population, invasive candidiasis is associated with a poor prognosis but adequate management can limit the attributable mortality. Adequate management, however, is hampered by a problematic diagnosis as the clinical picture of invasive disease is non-specific and blood cultures have a low sensitivity. Moreover, it is often hard to differentiate colonisation from infection and many critically ill patients are heavily colonised with Candida species, especially when receiving broad-spectrum antibacterials. The question of which antifungal agent to choose has become more complex as the development of new drugs raises promising expectations. Until the 1980s therapy for invasive candidiasis was limited to amphotericin B, but with the advent of new antifungal agents, such as azoles and echinocandins, less toxic therapeutic options are possible and doors have opened towards prevention and optimised therapy in the case of documented candidiasis. Through the arrival of these new antifungal agents, a range of therapeutic strategies for the management of invasive candidiasis has been developed: antifungal prophylaxis, pre-emptive therapy, and empirical and definitive antifungal therapy. Each of these strategies has a specific target population, as defined by specific underlying conditions and/or individual risk factors. Antifungal prophylaxis, in order to prevent candidal infection, is based on the type of underlying diseases with a high risk for invasive candidiasis. Individual risk factors are not taken into account. Potential indications are bone marrow transplantation, liver transplantation, recurrent gastrointestinal perforations or leakages, and surgery for acute necrotising pancreatitis. Pre-emptive therapy is also a preventive strategy. It can be recommended on the basis of an individual risk profile including overt candidal colonisation. Empirical therapy is started in patients with a risk profile for invasive candidiasis. It is recommended in the presence of clinical signs of infection, deteriorating clinical parameters, or a clinical picture of infection not responding to antibacterials but in the absence of a clear causative pathogen. Definitive antifungal therapy is defined as therapy in patients with documented invasive infection. The main goal is to maintain a balance between optimal prevention and timely initiation of therapy on one hand, and to minimise selection pressure in order to avoid a shift towards less susceptible Candida species on the other hand.

Subclinical iron deficiency is a strong predictor of bacterial vaginosis in early pregnancy

BACKGROUND

Bacterial vaginosis (BV) is the single most common vaginal infection in women of childbearing age and associated with a sizeable infectious disease burden among both non-pregnant and pregnant women, including a significantly elevated risk of adverse pregnancy outcome. Overall, little progress has been made in identifying causal factors involved in BV acquisition and persistence. We sought to evaluate maternal iron status in early pregnancy as a putative risk factor for BV, considering that micronutrients, and iron deficiency in particular, affect the host response against bacterial colonization, even in the setting of mild micronutrient deficiencies.

METHODS

In a nested case-control study, we compared maternal iron status at entry to prenatal care (mean gestational age 9.2 +/- 2.6 weeks) between eighty women with healthy vaginal microflora and eighteen women with vaginosis-like microflora. Vaginal microflora status was assessed by assigning a modified Nugent score to a Gram-stained vaginal smear. Maternal iron status was assayed by an array of conventional erythrocyte and serum indicators for iron status assessment, but also by more sensitive and more specific indicators of iron deficiency, including soluble transferrin receptors (sTfR) as an accurate measure of cellular and tissue iron deficiency and the iron deficiency log10[sTfR/ferritin] index as the presently most accurate measure of body storage iron available.

RESULTS

We found no statistically significant correlation between vaginal microflora status and routinely assessed iron parameters. In contrast, a highly significant difference between the healthy and vaginosis-like microflora groups of women was shown in mean values of sTfR concentrations (1.15 +/- 0.30 mg/L versus 1.37 +/- 0.38 mg/L, p = 0.008) and in mean iron deficiency log10[sTfR/ferritin] index values (1.57 +/- 0.30 versus 1.08 +/- 0.56, p = 0.003), indicating a strong association between iron deficiency and vaginosis-like microflora. An sTfR concentration > 1.45 mg/L was associated with a 3-fold increased risk (95%CI: 1.4-6.7) of vaginosis-like microflora and after controlling for maternal age, gestational length, body mass, parity, and smoking habits with an adjusted odds ratio of 4.5 (95%CI: 1.4-14.2).

CONCLUSION

We conclude that subclinical iron deficiency, presumably resulting from inadequate preconceptional iron supplies, is strongly and independently associated with vaginosis-like microflora during early pregnancy.

Ventilator-associated pneumonia in a tertiary care ICU: analysis of risk factors for acquisition and mortality

OBJECTIVE

To investigate the incidence, risk factors and mortality of ventilator-associated pneumonia (VAP) in intensive care unit (ICU) patients.

DESIGN

Prospective, observational, population-based study.

SETTING

The medical (14-bed) and surgical ICU (26-bed) of the Ghent University Hospital.

METHODS

All 1295 patients admitted to the ICU during 4 three-month periods between 1996 and 1998 were included. A set of demographic and clinical variables were collected at the day of admission and during the ICU course.

RESULTS

The incidence of VAP among ICU patients ventilated at least 48 hours was 23.1%. The mean time to the development of VAP was 9.6 days with a median of 6 days. In the population of patients ventilated for at least 48 hours, a comparison was made between patients with (n = 89) and without VAP (n = 296). Patients with VAP had a significant longer ICU stay, with a longer ventilation dependency. Logistic regression analysis identified admission diagnosis other than trauma (OR: 0.51, 95% CI: 0.29-0.89; p = 0.02) and the length of ICU stay (OR: 1.05, 95% CI: 1.03-1.07; p < 0.001) to be independently associated with the acquisiton of VAP. In comparison with the total study population, patients with VAP had a higher ICU mortality (20.2% vs. 12.0%; p = 0.04), but not in the cohort group of patients at risk for VAP (ventilated > 48 hours)(20.2% vs. 31.3%; p = 0.03). The factors independently associated with death were higher SAPS II scores (OR 1.02, 95% CI: 1.003-1.032; p = 0.02), an admission diagnosis other than trauma (OR 0.36, 95% CI: 0.17-0.75; p = 0.006) and length of ICU stay (OR 0.97, 95% CI: 0.946-0.995; p = 0.02). This model did not recognize VAP as an independent predictor of death (OR 0.79, 95% CI: 0.41-1.53; p = 0.492).

CONCLUSIONS

The incidence of VAP in our ICU is 23.1%. Length of ICU stay and an admission diagnosis other than trauma are major risk factors for the development of this nosocomial infection. VAP is associated with a high fatality rate. However, after adjustment for disease severity and length of ICU stay, VAP was not identified as an independent predictor of death.

First isolation of Mycobacterium microti (Llama-type) from a dog

We report the first isolation of Mycobacterium microti from a dog with lesions of acute peritonitis. The isolate was demonstrated to be M. microti of Llama-Type by spoligotyping. Epidemiological implications of the isolation of this possibly zoonotic agent from a dog are discussed.

European surveillance of antimicrobial consumption (ESAC): data collection performance and methodological approach

BACKGROUND

Europe is a continent with strong public healthcare systems, but diverging antibiotic policies and resistance patterns.

AIMS

To describe the performance and methodological approach in a retrospective data collection effort (1997-2001), through an international network of surveillance systems, aiming to collect publicly available, comparable and reliable data on antibiotic use in Europe.

METHODS

A central multidisciplinary management team co-ordinated a network of national representatives, liasing with national data providers and bodies responsible for antibiotic policy. The data collected were screened for bias, using a checklist. We focused on detection bias in sample and census data; errors in assigning medicinal product packages to the Anatomical Therapeutic Chemical Classification (ATC); errors in calculations of defined daily doses (DDD) per package; bias by over-the-counter sales and parallel trade; and bias in ambulatory care (AC)/hospital care (HC) mix. Datasets were corrected after national feedback, and classified as valid; valid but with minor bias; not valid.

RESULTS

Of the 31 participating countries, 21 countries delivered AC data suitable for cross-national comparison (14 for all 5 years). Of these, 17 countries provided data on a quarterly basis for at least 1 year. For HC, 14 countries were able to deliver valid data (nine for all 5 years). A valid estimate of the total exposure of national populations to human antibiotic consumption could be made in 17 countries.

CONCLUSION

In cross-national comparisons of antibiotic consumption in Europe, methodological rigour in correcting for various sources of bias and checking the validity of ATC/DDD assignment is needed.

Emergence of Antibiotic Resistance in Infected Pancreatic Necrosis

BACKGROUND

Overall, the use of antibiotics in the treatment of patients with severe acute pancreatitis has increased owing to the use of antibiotic prophylaxis.

HYPOTHESIS

The incidence of antibiotic-resistant (AB-R) bacteria in infected pancreatitis is related to prolonged antibiotic treatment and may affect outcome.

DESIGN

Case series.

SETTING

Fifty-six-bed intensive care unit of a tertiary care center.

PATIENTS

Forty-six consecutive patients with infected pancreatic necrosis.

MAIN OUTCOME MEASURES

Occurrence rate of AB-R organisms in pancreatic infection, overall duration of antibiotic treatment prior to infection, and mortality, defined as inhospital mortality.

RESULTS

Infection with AB-R microorganisms was found in 24 (52%) of 46 patients. Primary infection was present in 7 patients; in 21 patients, nosocomial surinfection with AB-R organisms occurred. Patients with AB-R infections were treated with antibiotics for a longer period (24 vs 15 days, P<.05), while disease severity and the incidence of organ failure were not statistically significantly different. The intensive care unit stay was significantly longer in patients with AB-R infections (23 vs 31 days, P = .02). Mortality was not statistically significantly different in patients with AB-R infections (37% vs 28%, P = .23).

CONCLUSIONS

The occurrence rate of infections with AB-R organisms in our patients with severe acute pancreatitis was high and was associated with a longer intensive care unit stay, but no increased mortality could be demonstrated. The duration of antibiotic treatment was increased in patients in whom AB-R infections developed.

Invasive aspergillosis in critically ill patients: analysis of risk factors for acquisition and mortality

OBJECTIVE

To investigate outcome in patients who develop invasive aspergillosis in the ICU, and to evaluate whether specific risk factors for the acquisition of invasive aspergillosis are associated with mortality.

DESIGN

Retrospective cohort study (07/1997-12/1999) with screening of 8988 admissions.

SETTING

54-bed ICU of the 1060-bed Ghent University Hospital.

PATIENTS

38 ICU patients with invasive aspergillosis. Invasive aspergillosis was defined as proven by positive histology and tissue culture and as probable by a combination of clinical suspicion as well as microbiological and radiological data. Seventeen patients had risk factors (neutropenia, haematological malignancy, immunosuppressive therapy). In the other 21 apparently immunocompetent patients, invasive aspergillosis was a complication following ARDS, COPD, pneumonia, acute liver failure, burns, severe bacterial infection and malnutrition.

MEASUREMENTS

Population characteristics and outcome were compared for patients with and without risk factors for the acquisition of invasive aspergillosis.

RESULTS

Patients with risk factors had higher APACHE II scores. No difference was found between patients with and without risk factors in in-hospital mortality (82% vs. 71%; p=0.431). In patients with specific risk factors, the observed mortality was not different from the mortality as expected on basis of the APACHE II (p=0.940). In patients without risk factors the observed mortality exceeded the expected mortality (p<0.001).

CONCLUSION

The incidence of invasive aspergillosis in this series is 4/1000 admissions. No difference in mortality was found between patients with and without risk factors for the acquisition of invasive aspergillosis. Yet, the prognosis of the patients without risk factors seems to alter more seriously by the development of this infection.

Bloodstream infections after surgery for severe acute pancreatitis

OBJECTIVE

To analyze the incidence and outcome of bloodstream infections (BSIs) in patients operated on for severe acute pancreatitis to identify the source and associated risk factors.

METHODS

We retrospectively (1995-2001) analyzed 45 patients treated surgically for severe acute pancreatitis. We recorded demographic characteristics, data on surgical and medical treatment and disease severity, the occurrence of BSIs, microbiological data concerning the BSIs and other infectious processes, the incidence of organ failure, and data on surgical and infectious complications.

RESULTS

Fifteen episodes of BSI were found in 7 of 45 patients (15%), with 18 organisms involved. In all but 1 episode, the source of the BSI was pancreatic necrosis. Most of the organisms were gram positive (11); the others were gram negative (6) or fungi (1). Mortality was statistically not different in patients with a BSI (57% vs. 35%). Multivariate analysis demonstrated that only the length of intensive care unit (ICU) stay was associated with the occurrence of BSIs (OR, 1.05; 95% CI, 1.02-1.09; P < 0.01).

CONCLUSION

A BSI is not a rare finding after surgery for severe acute pancreatitis, especially in patients with a prolonged ICU stay. The source is the infected necrosis in most of BSI episodes.

Fungal infections in patients with severe acute pancreatitis and the use of prophylactic therapy

Data from an 8-year period for 46 patients with severe acute pancreatitis and infected pancreatic necrosis were analyzed to determine the incidence of fungal infection, to identify risk factors for the development of fungal infection, and to assess the use of early fluconazole treatment. Intraabdominal fungal infection was found in 17 (37%) of 46 patients. Candida albicans was isolated most frequently (15 patients); Candida tropicalis and Candida krusei were found in 1 patient each. Characteristics of patients with fungal infection were not different from patients without fungal infection. The difference in mortality was not statistically significant between patients with fungal infection and patients without fungal infection. Early antifungal therapy (prophylactic or preemptive antifungal therapy) was administered to 18 patients, and only 3 of them developed fungal infection. In this cohort of critically ill patients, no risk factors for fungal infection could be demonstrated, and mortality among patients who received early antifungal therapy was not different. Early treatment with fluconazole seems to prevent fungal infection in these high-risk patients.

Nosocomial bacteremia involving Acinetobacter baumannii in critically ill patients: a matched cohort study

OBJECTIVE

To determine outcome and attributable mortality in critically ill patients with nosocomial bacteremia involving A. baumannii.

DESIGN

A retrospective matched cohort study in which all ICU patients with microbiologically documented A. baumannii bacteremia were defined as cases. Matching of the controls was based on equivalent APACHE II score (+/-2 points) and diagnostic category. Control patients were required to have an ICU stay equivalent to or longer than the case prior to onset of the bacteremia.

SETTING

The 54-bed ICU of the 1060-bed Ghent University Hospital.

PATIENTS

45 ICU patients with A. baumannii bacteremia and 90 matched control subjects without clinical or microbiological evidence of blood stream infection.

MEASUREMENTS

Population characteristics and in-hospital mortality rates of patients with A. baumannii bacteremia and their controls were compared. Attributable mortality is determined by subtracting the crude mortality rate of the controls from the crude mortality rate of the cases.

RESULTS

Patients with A. baumannii bacteremia had significantly more hemodynamic instability, longer ICU stay, and longer length of ventilator dependence than controls. In-hospital mortality rates for cases and controls were, respectively, 42.2% and 34.4%; thus the attributable mortality was 7.8%.

CONCLUSION

In critically ill patients A. baumannii bacteremia is not associated with a significantly increased mortality rate.

Reappraisal of attributable mortality in critically ill patients with nosocomial bacteraemia involving Pseudomonas aeruginosa

In a retrospective study, population characteristics and outcome were investigated in intensive care unit (ICU) patients with hospital-acquired Pseudomonas aeruginosa bacteraemia admitted over a seven-year period (January 1992 through December 1998). A matched cohort study was performed in which all ICU patients with P. aeruginosa bacteraemia were defined as cases (N=53). Matching (1:2 ratio) of the controls (N=106) was based on the APACHE II classification: an equal APACHE II score (+/-1 point) and an equal diagnostic category. Patients with P. aeruginosa bacteraemia had a higher incidence of acute respiratory failure, haemodynamic instability, a longer ICU stay and length of ventilator dependence (P<0.05). In-hospital mortalities for cases and controls were 62.3 vs. 47.2% respectively (P=0.073). Thus, the attributable mortality was 15.1% (95% confidence intervals: -1.0-31.2). In a multivariate survival analysis the APACHE II score was the only variable independently associated with mortality. In conclusion, P. aeruginosa bacteraemia is associated with a clinically relevant attributable mortality (15%). However, we could not find statistical evidence of P. aeruginosa being an independent predictor of mortality.

Nosocomial bacteremia caused by antibiotic-resistant gram-negative bacteria in critically ill patients: clinical outcome and length of hospitalization

Population characteristics and outcomes were retrospectively compared for critically ill patients with nosocomial bacteremia caused by antibiotic-susceptible (AB-S; n=208) or antibiotic-resistant (AB-R; n=120) gram-negative bacteria. No significant differences in severity of illness and comorbidity factors were seen between groups. Patients with bacteremia caused by AB-R strains had a longer hospitalization before the onset of the bacteremia. The in-hospital mortality for patients with bacteremia caused by AB-S strains was 41.8%; for patients infected with AB-R strains, it was 45.0% (P=.576). A multivariate survival analysis demonstrated that older age (P=.009), a high-risk source of bacteremia (abdominal and lower respiratory tract; P=.031), and a high acute physiology and chronic health evaluation II-related expected mortality (P=.032) were independently associated with in-hospital mortality (P<.05). Antibiotic resistance in nosocomial bacteremia caused by gram-negative bacteria does not adversely affect the outcome for critically ill patients.

Stereotactic CT-guided brain biopsy in the dog

This study evaluated the accuracy of a new stereotactic CT-guided brain biopsy (SCTGBB) device on 23 client-owned dogs which presented with a brain lesion. Biopsy of the lesion was achieved in 95 per cent of cases. The target tissue was not sampled in one dog. Complications were observed in six dogs. Two dogs with highly vascularised brainstem tumours died after SCTGBB. Minor complications (slight variation in the neurological status) were observed in a further four cases. A diagnosis was reached in 16 dogs after cytological examination and in 21 dogs after histological evaluation. SCTGBB is an accurate diagnostic method for the diagnosis of brain lesions.

The electroretinographic phenotype of dogs with Golden Retriever muscular dystrophy

OBJECTIVE

To characterize the flash electroretinogram (ERG) in the Golden Retriever muscular dystrophy (GRMD) dog and to compare the results with those from a control group of Golden Retrievers. To investigate whether similar abnormalities of the ERG as those found in a majority of human patients with Duchenne muscular dystrophy (DMD) are also observed in the GRMD dog, the canine model for DMD. Animals Five GRMD dogs and five age-matched clinically normal Golden Retrievers.

PROCEDURE

An ophthalmic examination was carried out prior to performing electroretinography under general anesthesia. Rod, combined rod-cone and oscillatory potentials responses were recorded after dark adaptation. Responses to 30-Hz-flicker were recorded after light adaptation. The ERG responses of the GRMD dogs were compared with those of the control dogs by use of a Wilcoxon signed rank test.

RESULTS

GRMD dogs had significantly reduced a and b-wave amplitudes after dim white flash stimuli (rod response) and reduced a-wave amplitude after bright white flash stimuli (rod-cone response).

CONCLUSION AND CLINICAL RELEVANCE

The ERG abnormalities observed in the GRMD dog suggest a dysfunction in the rod signaling pathway. These ERG alterations are different from those observed in human patients with DMD.

Outcome in critically ill patients with candidal fungaemia: Candida albicans vs. Candida glabrata

In a retrospective study (1 January 1992-12 December 1998), we investigated population characteristics and outcome in critically ill patients with fungaemia involving C. albicans (n=41) and C. glabrata (n=15). Patients with C. glabrata fungaemia were significantly older compared with patients in the C. albicans group (P=0.024). There were no other differences in population characteristics or severity of illness. Logistic regression analysis showed age (P=0.021), the presence of a polymicrobial blood stream infection (P=0.039), and renal failure (P=0.044) to be independent predictors of mortality. There was no significant difference in in-hospital mortality between the C. glabrata and C. albicans groups (60.0% vs. 41.5%; P=0.24). Since age was an independent predictor of mortality, the trend towards a higher mortality in patients with C. glabrata can be explained by this population being significantly older. In conclusion, we found no difference in mortality between patients with fungaemia involving C. albicans and C. glabrata.