Empirical antibiotic therapy for pneumonia in intensive care units: a multicentre, retrospective analysis of potentially pathogenic microorganisms identified by endotracheal aspirates cultures.

The purpose of this investigation was to explore the presumed relationship between the days of hospitalisation and microorganisms identified by endotracheal aspirate cultures in relation to adequate empirical treatment strategies of pneumonia in the intensive care unit (ICU). All potentially pathogenic microorganisms identified by (surveillance) cultures of endotracheal aspirates obtained in the ICUs of two Dutch teaching hospitals in 2007 and 2012 were retrospectively collected and analysed. Antibiotic susceptibilities to 11 antibiotics were calculated for several time points (days or weeks) after hospital admission and expressed per patient-day. In total, 4184 potentially pathogenic microorganisms identified in 782 patients were analysed. Prevalence of the classic early-onset pneumonia-causing microorganisms decreased from 55 % on the first four days to 34 % on days 4-6 after hospital admission (p < 0.0001). Susceptibility to amoxicillin/clavulanic acid was below 70 % on all days. Except for days 0 and 12, susceptibility to ceftriaxone was below 80 %. The overall susceptibility to piperacillin/tazobactam was 1518/1973 (77 %) in 2007 vs. 727/1008 (67 %) in 2012 (p < 0.0001). After day 8 of hospital admission, susceptibility to piperacillin/tazobactam therapy was below 80 % in 2012. After one week of hospital admission, susceptibilities to antibiotics were lower in the hospital that included that antibiotic in the local empirical treatment protocols as compared to the hospitals in which that antibiotic was not or infrequently included: 90/434 (21 %) vs. 117/398 (29 %); p = 0.004 for amoxicillin/clavulanic acid and 203/433 (47 %) vs. 253/398 (64 %); p < 0.001 for ceftriaxone. No cut-off in the number of days after hospital admission could be identified to distinguish early-onset from late-onset pneumonia. Consequently, the choice of empirical antibiotics should probably not be based on the time of onset.

Risk factors for mortality in patients with pulmonary infections with non-tuberculous mycobacteria: a retrospective cohort study.

BACKGROUND: Infections with non-tuberculous mycobacteria (NTM) represent an increasing problem. Their clinical relevance is still largely unknown as well as predictors for mortality in affected patients. The objective was to describe prevalence and clinical relevance of different NTM and to identify risk factors for mortality. METHODS: Retrospective cohort study of 124 patients with NTM detection between January 2001 and December 2011. Clinical characteristics like symptoms and radiological appearance were assessed at presentation. The primary outcome was all cause mortality during the follow-up period. Univariate and multivariate survival analyses using Cox proportional hazard models were employed for statistical analysis. RESULTS: Over the study period, the frequency of NTM isolation varied from 4 to 12 patients per year. Twenty-nine out of 124 patients (23%) had a clinically relevant infection, according to the criteria of the American Thoracic Society (ATS). Mycobacterium avium was isolated most frequently, but Mycobacterium kansasii, Mycobacterium malmoense and Mycobacterium xenopi had the highest clinical relevance. Symptoms were mostly diverse and non-specific. On radiology, cavities were observed more frequently than a nodular-bronchiectatic variant or consolidation. In 75% of all patients, follow up time was more than two years. Median survival was 6.5 years (95%CI = 2.7-10.3). Factors significantly influencing survival time were haemoptysis (HR = 0.2, 95%CI = 0.1-0.6) and a consolidation on imaging (HR = 5.1, 95%CI 1.4-18.2). CONCLUSIONS: The presentation of an infection with NTM can be diverse and depends mainly on the causative NTM pathogen. The most important predictor for increased mortality is the radiological appearance of a consolidation.

Comparison of three different techniques for the isolation of viral RNA in sputum.

BACKGROUND: Respiratory infections are a major cause of morbidity and mortality worldwide. A high percentage of all respiratory tract infections are caused by RNA viruses. Real-time PCR is a highly sensitive method for the detection of respiratory viruses in clinical samples. A good RNA isolation protocol is of high importance, since RNA is more unstable than DNA and many clinical samples contain RNAses. OBJECTIVES: To evaluate the performance of three different RNA extraction protocols for the extraction of respiratory viral RNA from sputum samples obtained from patients with the suspicion of a viral respiratory tract infection. STUDY DESIGN: A total of 50 sputum samples, PCR positive for a respiratory RNA virus, were used for viral RNA isolation with the phenol/chloroform method, RTP(®) DNA/RNA virus mini kit and the automated MagNa Pure LC (MPLC) extraction system. After isolation, real-time PCR was performed for the detection of viral RNA in the sputum samples. RESULTS: The MPLC extraction increased the detection probability from 82% (phenol/chloroform) and 86% (RTP(®) DNA/RNA virus mini kit) to 94%. In 16% the RTP(®) DNA/RNA virus mini kit resulted in lower Ct values compared to the phenol/chloroform method, while in 32% the phenol/chloroform resulted in lower Ct values. CONCLUSIONS: The extraction of viral RNA performed with the MPLC extraction method was superior to the extraction with the RTP(®) DNA/RNA virus mini kit and to the extraction with phenol/chloroform. In general, there was no difference in the detection of viral RNA between the phenol/chloroform extraction method and the RTP(®) DNA/RNA virus mini kit.

Mimivirus is not a frequent cause of ventilator-associated pneumonia in critically ill patients.

Acanthamoeba polyphaga mimivirus (APMV) belongs to the amoebae-associated microorganisms. Antibodies to APMV have been found in patients with pneumonia suggesting a potential role as a respiratory pathogen. In addition, positive serology for APMV was associated with an increased duration of mechanical ventilation and intensive care unit stay in patients with ventilator-associated pneumonia. The aim of the present study was to assess the presence of APMV in bronchoalveolar lavage fluid samples of critically ill patients suspected of ventilator-associated pneumonia. The study was conducted in the intensive care unit of the Maastricht University Medical Centre. All consecutive bronchoalveolar lavage fluid samples obtained between January 2005 and October 2009 from patients suspected of ventilator-associated pneumonia were eligible for inclusion. All samples were analyzed by real-time PCR targeting the APMV. A total of 260 bronchoalveolar lavage fluid samples from 214 patients (139 male, 75 female) were included. Bacterial ventilator-associated pneumonia was confirmed microbiologically in 105 out of 260 (40%) suspected episodes of ventilator-associated pneumonia (86 patients). The presence of APMV DNA could not be demonstrated in the bacterial ventilator-associated pneumonia positive or in the bacterial ventilator-associated pneumonia negative bronchoalveolar lavage fluid samples. Although suspected, APMV appeared not to be present in critically ill patients suspected of ventilator-associated pneumonia, and APMV does not seem to be a frequent cause of ventilator-associated pneumonia.

Infections with mimivirus in patients with chronic obstructive pulmonary disease.

INTRODUCTION: Antibodies against mimivirus, a recently discovered giant virus, have been found in patients presenting with pneumonia suggesting a potential role for this virus as a respiratory pathogen. Several bacterial and viral pathogens have been associated with the occurrence of acute exacerbations in COPD. However, a large part of these exacerbations have an unknown cause. In the present study we evaluated the presence of mimivirus in sputum samples of COPD patients. METHODS: From March 2009 until January 2010 all sputum samples collected during stable conditions and during exacerbations of COPD patients, referred for pulmonary rehabilitation, were included. All sputum samples were analysed by real-time PCR targeting mimivirus. Furthermore, serum samples were analysed for the presence of antibodies against mimivirus. RESULTS: A total of 220 sputum samples from 109 patients were eligible for inclusion. None of the sputum samples showed the presence of mimivirus DNA. Antibodies against mimivirus were detected in 3 serum samples from 3 patients, of which one showed an increase in antibody-titre. CONCLUSIONS: Although mimivirus was suggested as a potential respiratory pathogen, its presence could not be confirmed in the present study-population of patients with COPD.

Delirium and cognitive disorders after cardiac operations: relationship to pre- and intraoperative quantitative electroencephalogram.

We examined the incidence of delirium and cognitive disorders after cardiac operations and the related risk factors. The value of pre- and intraoperative QEEG was determined. Using the Mini-Mental State Examination and the Saskatoon Delirium Checklist, 321 patients were tested during the immediate postoperative period. Forty-four patients (14%) showed delirium, 68 (23%) cognitive disorders and 26 (9%) both. Significant risk factors for the development of cognitive disorders were age > or = 70 yr, female gender, duration of cardiopulmonary bypass > or = 2.5 h and aorta-cross-clamping > 70 min. Risk factors for delirium were age > or = 70 yr, female gender and Hb < 5 mmol 1(-1) intraoperatively. The preoperative QEEG showed significant differences between the groups with and without a cognitive disorder, while the intraoperative QEEG showed significant differences between the groups with and without delirium. Different risk factors for delirium and cognitive disorders are a possible explanation for the controversies in the literature, where neuropsychologic complications were grouped together. A low intraoperative Hb is an important risk factor for the development of delirium and can be treated. The preoperative QEEG may have prognostic significance in the occurrence of cognitive disorders, while the intraoperative QEEG may have prognostic significance in the occurrence of delirium.