Authoritative guidelines state that the diagnosis of ventilator-associated pneumonia (VAP) can be established using either endotracheal aspirate (ETA) or bronchoalveolar lavage fluid (BALF) analysis, thereby suggesting that their results are considered to be in accordance. Therefore, the results of ETA Gram staining and semiquantitative cultures were compared to the results from a paired ETA-BALF analysis. Different thresholds for the positivity of ETAs were assessed. This was a prospective study of all patients who underwent bronchoalveolar lavage for suspected VAP in a 27-bed university intensive care unit during an 8-year period. VAP was diagnosed when >2% of the BALF cells contained intracellular organisms and/or when BALF quantitative culture revealed >104 CFU/ml of potentially pathogenic microorganisms. ETA Gram staining and semiquantitative cultures were compared to the results from paired BALF analysis by Cohen's kappa coefficients. VAP was suspected in 311 patients and diagnosed in 122 (39%) patients. In 288 (93%) patients, the results from the ETA analysis were available for comparison. Depending on the threshold used and the diagnostic modality, VAP incidences varied from 15% to 68%. For the diagnosis of VAP, the most accurate threshold for positivity of ETA semiquantitative cultures was moderate or heavy growth, whereas the optimal threshold for BALF Gram staining was >1 microorganisms per high power field. The Cohen's kappa coefficients were 0.22, 0.31, and 0.60 for ETA and paired BALF Gram stains, cultures, and BALF Gram stains, respectively. Since the ETA and BALF Gram stains and cultures agreed only fairly, they are probably not interchangeable for diagnosing VAP.

Stenotrophomonas maltophilia is a possible, yet infrequent cause of VAP. No outcome differences were found when compared to matched VAP caused by other Gram-negative bacilli.

The aim of this study was to investigate the methicillin-resistant Staphylococcus aureus (MRSA) clones isolated in a Dutch university hospital, situated near the borders of Belgium and Germany, between 2002 and 2006. MRSA strains (n = 175) were characterized using spa and SCCmec typing. The presence of Panton Valentine leukocidin (PVL) was determined. Between 2002 and 2005, ST5-MRSA-IV was predominant, and the spa type of ST5-MRSA-IV changed from t002 to t447. ST5-MRSA-I, ST5-MRSA-II, ST228-MRSA-I, and ST247-MRSA-I were also observed in this period. From 2004, the MRSA genetic background became more diverse, and in 2006, ST5-MRSA-IV was only sporadically observed. From 2005, ST5-MRSA-II, ST8-MRSA-IV, ST22-MRSA-IV, and ST45-MRSA-IV were increasingly observed. Several other MRSA clones, such as ST239-MRSA-III, were found sporadically. Four PVL-positive MRSA isolates were observed, associated with ST80-MRSA-IV and ST8-MRSA-IV. ST5-MRSA-I, ST5-MRSA-II, ST5-MRSA-IV, and ST228-MRSA-I have not been described previously in The Netherlands.

BackgroundThe significance of commensal oropharyngeal flora (COF) as a potential cause of ventilator-associated pneumonia (VAP) is scarcely investigated and consequently unknown. Therefore, the aim of this study was to explore whether COF may cause VAP.MethodsRetrospective clinical, microbiological and radiographic analysis of all prospectively collected suspected VAP cases in which bronchoalveolar lavage fluid exclusively yielded ≥ 104 cfu/ml COF during a 9.5-year period. Characteristics of 899 recent intensive care unit (ICU) admissions were used as a reference population.ResultsOut of the prospectively collected database containing 159 VAP cases, 23 patients were included. In these patients, VAP developed after a median of 8 days of mechanical ventilation. The patients faced a prolonged total ICU length of stay (35 days [P < .001]), hospital length of stay (45 days [P = .001]), and a trend to higher mortality (39 % vs. 26 %, [P = .158]; standardized mortality ratio 1.26 vs. 0.77, [P = .137]) compared to the reference population. After clinical, microbiological and radiographic analysis, COF was the most likely cause of respiratory deterioration in 15 patients (9.4 % of all VAP cases) and a possible cause in 2 patients.ConclusionCommensal oropharyngeal flora appears to be a potential cause of VAP in limited numbers of ICU patients as is probably associated with an increased length of stay in both ICU and hospital. As COF-VAP develops late in the course of ICU admission, it is possibly associated with the immunocompromised status of ICU patients.

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