PubMed Health⌕ Search

Biomedical subjects

Stijn Blot

Publications and source records attributed to Stijn Blot.

13 recordsLinked to original sources

Outcome in bacteremia associated with nosocomial pneumonia and the impact of pathogen prediction by tracheal surveillance cultures.

OBJECTIVE: To assess whether pathogen prediction in bacteremia associated with nosocomial pneumonia (NP) by tracheal surveillance cultures improves adequacy of early antibiotic therapy and impacts mortality. DESIGN AND SETTING: A retrospective observational study of a prospectively gathered cohort. This cohort included all adult patients admitted to the ICU of a tertiary care hospital from 1992 through 2001 and who developed bacteremia associated with NP. MEASUREMENTS AND MAIN RESULTS: 128 episodes of bacteremia associated with NP were identified. In 110 episodes a tracheal surveillance culture 48-96h prior to bacteremia was available: this culture predicted the pathogen in 67 episodes (61%). Overall rates of appropriate empiric antibiotic therapy within 24 and 48h were 62 and 87%, respectively. Pathogen prediction was associated with a significantly higher rate of appropriate antibiotic therapy within 24h (71 vs 45%; p=0.01), but not within 48h (91 vs 82%; p=0.15). Crude in-hospital mortality was 50%. Pathogen prediction was associated with increased survival in univariate (OR 0.43; CI 0.19-0.93; p=0.04) and multivariate analysis (OR 0.32; CI 0.12-0.82; p=0.02). Multivariate analysis further identified age (OR 1.04; CI 1.01-1.07; p=0.02), increasing APACHEII score (OR 1.08; CI 1.02-1.15; p=0.01), and methicillin-resistant Staphylococcus aureus (OR 5.90; CI 1.36-25.36; p=0.01) and Pseudomonas aeruginosa (OR 3.30; CI 1.04-10.4; p=0.04) as independent risk factors for mortality. CONCLUSION: Pathogen prediction in bacteremia associated with NP by tracheal surveillance cultures is associated with a higher rate of adequate empiric antibiotic therapy within 24[Symbol: see text]h and with increased survival.

Aged↗

Nosocomial pneumonia: aetiology, diagnosis and treatment.

PURPOSE OF REVIEW: This review highlights recent advances in the aetiology of nosocomial pneumonia, and in strategies to increase accuracy of diagnosis and antibiotic prescription while limiting unnecessary antibiotic consumption. RECENT FINDINGS: Bacterial pathogens still cause the bulk of nosocomial pneumonia and are of concern because of ever-rising antimicrobial resistance. Yet, the pathogenic role of fungal and viral organisms is increasingly recognized. Since early appropriate antimicrobial therapy is the cornerstone of an effective treatment, further studies have been conducted to improve appropriateness of early antibiotic therapy. De-escalation strategies combine initial broad-spectrum antibiotics to maximize early antibiotic coverage with a subsequent focusing of the antibiotic spectrum when the cause is identified. Invasive techniques probably do not alter the immediate outcome but have the potential to reduce unnecessary antibiotic exposure. Decisions to stop or change antibiotic therapy are hampered due to a lack of reliable parameters to assess the resolution of pneumonia. SUMMARY: Increasing antimicrobial resistance in nosocomial pneumonia both challenges treatment and mandates limitation of selection pressure by reducing antibiotic burden. Treating physicians should be both aggressive in initiating antimicrobials when suspecting nosocomial pneumonia but willing to discontinue antimicrobials when diagnostic results point to an alternative diagnosis. Efforts should be made to limit duration of antibiotic therapy when possible.

Anti-Infective Agents↗

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.

Adult↗

Influence of matching for exposure time on estimates of attributable mortality caused by nosocomial bacteremia in critically ill patients.

OBJECTIVE: To evaluate the influence of matching on exposure time on estimates of attributable mortality of nosocomial bacteremia as assessed by matched cohort studies. DESIGN: Two retrospective, pairwise-matched (1:2) cohort studies. SETTING: A 54-bed intensive care unit (ICU) in a university hospital. PATIENTS: Patients with nosocomial Escherichia coli bacteremia (n = 68) and control-patients without nosocomial bacteremia (n = 136 for each matched cohort study). INTERVENTION: In both matched cohort studies, the same set of bacteremic patients was matched with control-patients using the APACHE II system. In the first study, control-patients were required to have an ICU stay at least as long as the respective bacteremic patient prior to onset of bacteremia (matching on exposure time). In the second study, control-patients were required to have an ICU stay shorter than the stay prior to the development of bacteremia in the respective bacteremic patient (no matching on exposure time). RESULTS: For bacteremic patients, the mean ICU stay before onset of the bacteremia was 9 days (median, 6 days). In the first matched cohort study, hospital mortality was not different between bacteremic patients and control-patients (44.1% vs 43.4%; P = .999). In the second study, mortality of bacteremic patients and control-patients was also not different (44.1% vs 47.8%; P = .657). Mortality rates between control groups were not different (43.4% vs 47.8%; P = .543). CONCLUSION: Matching or not matching on exposure time did not alter the estimate of attributable mortality for ICU patients with E. coli bacteremia.

APACHE↗

Colonization status and appropriate antibiotic therapy for nosocomial bacteremia caused by antibiotic-resistant gram-negative bacteria in an intensive care unit.

OBJECTIVE: Timely initiation of antibiotic therapy is crucial for severe infection. Appropriate antibiotic therapy is often delayed for nosocomial infections caused by antibiotic-resistant bacteria. The relationship between knowledge of colonization caused by antibiotic-resistant gram-negative bacteria (ABR-GNB) and rate of appropriate initial antibiotic therapy for subsequent bacteremia was evaluated. DESIGN: Retrospective cohort study. SETTING: Fifty-four-bed intensive care unit (ICU) of a university hospital. In this unit, colonization surveillance is performed through routine site-specific surveillance cultures (urine, mouth, trachea, and anus). Additional cultures are performed when presumed clinically relevant. PATIENTS: ICU patients with nosocomial bacteremia caused by ABR-GNB. RESULTS: Infectious and microbiological characteristics and rates of appropriate antibiotic therapy were compared between patients with and without colonization prior to bacteremia. Prior colonization was defined as the presence (detected > or = 2 days before the onset of bacteremia) of the same ABR-GNB in colonization and subsequent blood cultures. During the study period, 157 episodes of bacteremia caused by ABR-GNB were suitable for evaluation. One hundred seventeen episodes of bacteremia (74.5%) were preceded by colonization. Appropriate empiric antibiotic therapy (started within 24 hours) was administered for 74.4% of these episodes versus 55.0% of the episodes that occurred without prior colonization. Appropriate therapy was administered within 48 hours for all episodes preceded by colonization versus 90.0% of episodes without prior colonization. CONCLUSION: Knowledge of colonization status prior to infection is associated with higher rates of appropriate therapy for patients with bacteremia caused by ABR-GNB.

Anal Canal↗

Critical issues in the clinical management of complicated intra-abdominal infections.

Intra-abdominal infections differ from other infections through the broad variety in causes and severity of the infection, the aetiology of which is often polymicrobial, the microbiological results that are difficult to interpret and the essential role of surgical intervention. From a clinical viewpoint, two major types of intra-abdominal infections can be distinguished: uncomplicated and complicated. In uncomplicated intra-abdominal infection, the infectious process only involves a single organ and no anatomical disruption is present. Generally, patients with such infections can be managed with surgical resection alone and no antimicrobial therapy besides perioperative prophylaxis is necessary. In complicated intra-abdominal infections, the infectious process proceeds beyond the organ that is the source of the infection, and causes either localised peritonitis, also referred to as abdominal abscess, or diffuse peritonitis, depending on the ability of the host to contain the process within a part of the abdominal cavity. In particular, complicated intra-abdominal infections are an important cause of morbidity and are more frequently associated with a poor prognosis. However, an early clinical diagnosis, followed by adequate source control to stop ongoing contamination and restore anatomical structures and physiological function, as well as prompt initiation of appropriate empirical therapy, can limit the associated mortality. The biggest challenge with complicated intra-abdominal infections is early recognition of the problem. Antimicrobial management is generally standardised and many regimens, either with monotherapy or combination therapy, have proven their efficacy. Routine coverage against enterococci is not recommended, but can be useful in particular clinical conditions such as the presence of septic shock in patients previously receiving prolonged treatment with cephalosporins, immunosuppressed patients at risk for bacteraemia, the presence of prosthetic heart valves and recurrent intra-abdominal infection accompanied by severe sepsis. In patients with prolonged hospital stay and antibacterial therapy, the likelihood of involvement of antibacterial-resistant pathogens must be taken into account. Antimicrobial coverage of Candida spp. is recommended when there is evidence of candidal involvement or in patients with specific risk factors for invasive candidiasis such as immunodeficiency and prolonged antibacterial exposure. In general, antimicrobial therapy should be continued for 5-7 days. If sepsis is still present after 1 week, a diagnostic work up should be performed, and if necessary a surgical reintervention should be considered.

Abdominal Abscess↗

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.

Acute Disease↗

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.

Antifungal Agents↗

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.

Acinetobacter↗

Absence of excess mortality in critically ill patients with nosocomial Escherichia coli bacteremia.

OBJECTIVE: To evaluate excess mortality in critically ill patients with Escherichia coli bacteremia after adjustment for severity of illness. DESIGN: Retrospective (1992-2000), pairwise-matched (1:2), risk-adjusted cohort study. SETTING: Fifty-four-bed ICU in a university hospital including a medical and surgical ICU, a unit for care after cardiac surgery, and a burns unit. PATIENTS: ICU patients with nosocomial E. coli bacteremia (defined as cases; n = 64) and control-patients without nosocomial bloodstream infection (n = 128). METHODS: Case-patients were matched with control-patients on the basis of the Acute Physiology and Chronic Health Evaluation (APACHE) II system: an equal APACHE II score (+/- 2 points) and diagnostic category. In addition, control-patients were required to have an ICU stay at least as long as that of the respective case-patients prior to onset of the bacteremia. RESULTS: The overall rate of appropriate antibiotic therapy in patients with E. coli bacteremia was high (93%) and such therapy was initiated soon after onset of the bacteremia (0.6 +/- 1.0 day). ICU patients with E. coli bacteremia had more acute renal failure. No differences were noted between case-patients and control-patients in incidence of acute respiratory failure, hemodynamic instability, or age. No differences were observed in length of mechanical ventilation or length of ICU stay. In-hospital mortality rates for cases and controls were not different (43.8% and 45.3%, respectively; P = .959). CONCLUSION: After adjustment for disease severity and acute illness and in the presence of adequate antibiotic therapy, no excess mortality was found in ICU patients with E. coli bacteremia.

APACHE↗

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.

Bacteremia↗