Environmental survival of vancomycin-sensitive ampicillin-resistant Enterococcus faecium (AREfm).

Ampicillin-resistant Enterococcus faecium (AREfm) has gained increased footholds in many hospital intensive care units (ICUs) and belongs to specific hospital-adapted E. faecium sub-populations. Three AREfm strains survived in an in vitro survival setting for approximately 5.5 years. These findings have important consequences for the epidemiology of AREfm in hospital settings and stress the importance of maintaining a good level of hospital hygiene.

Comparison of an enrichment broth-enhanced commercial PCR procedure versus bacteriological culture for separating non-colonized from suspected or colonized MRSA individuals.

The aim of the study presented here was to evaluate an enrichment broth-enhanced commercial PCR procedure for excluding the presence of meticillin-resistant Staphylococcus aureus (MRSA) in patient samples in less than 36 h. In The Netherlands to date, all MRSA epidemics have been successfully controlled with the Dutch search-and-destroy policy. However, PCR facilitates more rapid screening for MRSA than traditional culture. One commercial PCR option is the hyplex StaphyloResist(R) PCR assay (Biologische Analysensystem GmbH, Lich, Germany), which detects Staphylococcus aureus and the mecA gene in MRSA as well as in coagulase-negative staphylococci (CoNS). This assay was used to test a total of 939 specimens obtained from 346 individuals. Following resolution of all discrepancies, the prevalence, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for all separate specimens were 9.0, 97.6, 83.7, 37.4 and 99.7%, respectively, and for specimens grouped according to daily episode submitted per individual, they were 7.5, 97.4, 77.2, 26.2 and 99.7%, respectively. These results led to the introduction of this PCR into the hospital laboratory's routine for the purpose outlined above.

Cytocentrifugation conditions affecting the differential cell count in bronchoalveolar lavage fluid.

OBJECTIVE: To investigate variations in speed, duration and acceleration rate of the Cytospin 3 cytocentrifuge (Shandon Scientific Ltd., Astmoor, England) on the differential cell count of bronchoalveolar lavage (BAL) fluid samples. STUDY DESIGN: BAL fluid samples (n = 51) were cytocentrifuged at various combinations of speed (500, 1,200 and 2,000 rpm), acceleration rate (low, medium and high) and duration (5, 10, 15 and 20 minutes). The preparations were May-Grünwald-Giemsa stained and differentiated on 500 cells. Data were analyzed by mixed model repeated measurements ANOVA. RESULTS: The mean lymphocyte count was significantly higher at 1,200 rpm than at 500 rpm, whereas the macrophage count decreased. Between 1,200 and 2,000 rpm, the number of both cell types stabilized. Significantly higher numbers of lymphocytes were recorded at 10 and 15 minutes of cytocentrifugation than at 5 minutes. The acceleration rate did not influence the differential cell count. Seventeen BAL fluid samples were selected to test the diagnostic impact of cell damage using a validated computer program. In 1 of 17 samples the predicted diagnosis did not correspond between two different speeds (500 and 2,000 rpm). CONCLUSION: Variations in cytocentrifugation speed and duration affected the mean lymphocyte and macrophage counts of BAL fluid samples.

Correlation of leukocyte esterase detection by reagent strips and the presence of neutrophils: a study in BAL fluid.

STUDY OBJECTIVE: In the present study, we evaluated the leukocyte esterase (LE) area of a reagent strip designed for urinalysis for the semiquantitative measurement of the percentage of polymorphonuclear neutrophils (PMNs) in BAL fluid. DESIGN: Prospective. The relative PMN counts (obtained by conventional microscopy and expressed as a percentage of a 500 cell count) of consecutive BAL fluid samples were compared with the corresponding LE categories as read with a urine chemistry reader. LE categories were graded as follows: negative, trace, +, + +, and + + +. RESULTS: A total of 153 BAL fluid samples were included. The mean PMN counts of the negative LE category (4.1 +/- 4.3%; n = 43) and the + + + category (81.8 +/- 16.3%; n = 37) differed significantly from each other and from the mean PMN counts of the other categories. Within the trace, +, and + + categories, a considerable overlap of PMN counts was noted. Assignment of a BAL fluid to the negative LE category consistently predicted a PMN count < 20%. At a threshold value of 50% PMNs, the + + + LE category predicted the BAL fluid samples to the correct group (PMNs > 50% vs < 50%) with a sensitivity of 70.8% and a specificity of 97.1%. CONCLUSIONS: The reagent strips proved to be useful as a rapid test for semiquantitative measurement of the relative PMN counts in BAL fluid. However, the low predictive value for the exclusion of a high PMN count may limit their application.

Accuracy and precision of quantitative calibrated loops in transfer of bronchoalveolar lavage fluid.

Quantitative cultures of bronchoalveolar lavage (BAL) fluid are important in the diagnosis of ventilator-associated pneumonia, and calibrated loops are commonly used to set up these cultures. In this study, the performances of calibrated 0.010- and 0.001-ml loops in the transfer of BAL fluid were determined. Five loops of one lot from seven manufacturers were tested. Calibrations were performed by the gravimetric method (0.010-ml loops) and the colorimetric method (0.001-ml loops). Most of the 0.010-ml loops displayed a precision that was less than 10%, but six of them showed very poor accuracies as they transferred a deficiency (nichrome loops) or an excess (disposable loops) of BAL fluid that exceeded +/-10%. The mean maximum and minimum BAL fluid volumes delivered by the 0.010-ml loops differed by a factor 3. The 0.001-ml loops displayed acceptable precision. Five of them showed inaccuracies of

Differential cell analysis of cytocentrifuged bronchoalveolar fluid samples affected by the area counted.

OBJECTIVE: To investigate variations in the differential cell counts between the quadrants of cytocentrifuged bronchoalveolar lavage (BAL) fluid preparations and to evaluate the diagnostic impact of these differences in interstitial lung diseases (ILD). STUDY DESIGN: BAL fluid samples obtained from 30 patients suspected of having ILD or pneumonia were cytocentrifuged and additionally stained with May-Grünwald-Giemsa stain. Two observers differentiated 200 cells in each quadrant as well as in a circular pattern around the center of the cytocentrifuge spot. RESULTS: Lymphocytes and alveolar macrophages were not randomly distributed on the cytocentrifuge spot. Ten samples of patients with histologically confirmed ILD were selected to test the diagnostic impact using a validated computer program. The predicted diagnosis did not correspond to the histologic diagnosis for one quadrant from 1 of these 10 samples (sarcoidosis instead of idiopathic pulmonary fibrosis), whereas the differential cell counts performed around the center of the cytocentrifuge spot provided the correct diagnosis in all cases. CONCLUSION: BAL fluid differential cell counts varied between the quadrants of the cytocentrifuge spot. The center of the cytocentrifuge spot appeared to be the most reliable area. Therefore, cell counting is recommended in a circular pattern around the center of the cytocentrifuge spot.

Detection of non-infectious conditions mimicking pneumonia in the intensive care setting: usefulness of bronchoalveolar fluid cytology.

The present study investigated the usefulness of bronchoalveolar (BAL) fluid cytology in the identification of non-infectious pulmonary conditions in patients hospitalized in the intensive care unit (ICU) and suspected of pneumonia. A total of 182 BAL fluid samples obtained during a 27-month period from 130 ICU patients with suspected pneumonia were quantitatively cultured and investigated for opportunistic pathogens. Cytocentrifuged preparations stained with the May-Grünwald Giemsa and Perls's methods were reviewed. A non-infectious aetiology was considered when cultures yielded micro-organisms in quantities < 10(3) colony-forming units (CFU) per ml, in the absence of any other pathogen and in conjunction with one or more of the following cytological findings: > 20% haemosiderin macrophages, > 10% lymphocytes, the presence of activated lymphocytes, plasma cells, > 5% eosinophils, a preponderance of foamy macrophages, reactive type II pneumocytes or malignant cells. Patients' clinical records were reviewed to identify a clinical diagnosis for these episodes. In thirty-five (19.2%) BAL fluid samples from 26 patients, the cytological findings pointed to a non-infectious origin. An alternative diagnosis was ascertained in 20 of 26 patients. Diagnoses included: drug-induced pneumonitis (n = 7), aspiration of gastric contents (n = 2), pulmonary emboli (n = 3), adult respiratory distress syndrome (n = 4), lung contusion (n = 1), cardiogenic pulmonary oedema (n = 1), and carcinomatous lymphangitis (n = 2). The BAL fluid cytological findings were readily discernable and proved to be useful in the diagnostic work-up of samples obtained from ICU patients with suspected pneumonia.