Quantitative Bronchoalveolar Lavage Cultures Research Articles

Using bronchoalveolar lavage to distinguish nosocomial pneumonia from systemic inflammatory response syndrome: a prospective analysis.

Ventilator-associated pneumonia (PN) is difficult to distinguish from trauma-induced systemic inflammatory response syndrome (SIRS), especially in patients with multiple injuries. Previous work using bronchoscopy and quantitative cultures demonstrated significant bacterial growth in about one-third of patients with clinical evidence of PN. In this prospective study, antibiotic therapy for PN was based solely on quantitative bronchoalveolar lavage (BAL) cultures. Mechanically ventilated trauma patients underwent bronchoscopy with BAL when they developed clinical evidence of PN: fever (temperature > 100.5 degrees F), white blood cells > 10,000 or > 10% immature forms, purulent sputum, and new or changing infiltrate on chest roentgenogram. Patients with other infections or those receiving antibiotics for any other reason were excluded. Empiric antibiotic therapy for PN was started at the time of BAL. If the quantitative cultures revealed > or = 10(5) colony-forming units (CFU)/mL, that patient was defined as having PN and was treated. If the cultures revealed < 10(5) CFU/mL, that patient was defined as having SIRS, and empiric therapy was stopped. Forty-three patients (88% blunt, 12% penetrating) underwent bronchoscopy with BAL 55 times. Mean age was 40 and Injury Severity Score was 25. Twenty patients had > or = 10(5) CFU/mL (47%) and 23 had < 10(5) CFU/mL (53%). There were no differences in age, Injury Severity Score, temperature, white blood cell count, or ventilator days before BAL between groups. Sixty-five percent of those with SIRS improved after empiric therapy was stopped (average 3.3 days), and 35% underwent repeat BAL. Three patients with the initial diagnosis of SIRS developed PN (13% of SIRS). Mortality for PN was 15%, compared with 17% for SIRS; no deaths were related to antibiotic therapy. SIRS, which can mimic PN, is common in trauma patients. These entities can be distinguished by bronchoscopy with BAL. Basing antibiotic therapy solely on quantitative BAL cultures is efficacious in trauma patients.

1103 Lung cancer at diagnosis and respiratory infections

The prevalence of pulmonary infections in lung cancer at diagnosis was investigated in 96 patients submitted to bronchoscopy showing endobronchial tumor. Bronchoalveolar lavage (BAL) was carried-out instilling 60 ml of steril normal saline; The fluid recovered was immediately cultured for quantitative microbiological analysis. 42 micro-organisms (m.o.) were cultured from the BAL fluids of 33 patients (34.3%). 50% were Gram− 33% Gram+, 17 other m.o. Haemophilus species were the most frequent Gram− Staphilo coccus Aureus the most frequent Gram+. No relationship was found between respiratory infections and stage of the disease, performance status, histologic type, immunoregulatory ratio and serum lymphocyte subsets. A quantitative BAL culture may be useful in patients with lung cancer at diagnosis, as respiratory infections are frequent and, if unrecognized and untreated, can become a risk factor when immunocompetence is impaired by chemotherapy or advancement in the stage of malignancy.

Pulmonary infection during the acute respiratory distress syndrome.

Pulmonary infection is thought to be a common complication of ARDS. We undertook this prospective study to determine the incidence of pulmonary infection in patients with ARDS, and to evaluate the impact of nosocomial pneumonia on severity of ARDS and on survival. Two hundred one bronchoscopies were performed in 105 patients with ARDS with retrieval of distal airway secretions by bronchoalveolar lavage (BAL) and protected specimen brush (PSB). Whenever possible, bronchoscopy was performed at predetermined times: Day 3, Day 7, Day 14, and Day 21 after the onset of ARDS. The majority of patients were receiving antibiotics at the time of study. Changes in bacterial flora over time were determined by quantitative cultures of BAL and PSB. Bacterial growth was common, but usually at small concentrations. Only 16 patients met quantitative culture criteria for pneumonia (PSB > or = 10(3) cfu/ml or BAL > or = 10(4) cfu/ml). Correlation was poor between clinical evidence of pneumonia and pneumonia by quantitative culture criteria: clinical criteria had a very low sensitivity (24%) for predicting positive quantitative culture results, and a low specificity (77%) for predicting negative quantitative culture results. There was no correlation between total colony counts on BAL or PSB and severity of ARDS as judged by Pao2/FIo2 ratios, days receiving ventilation, or compliance. Furthermore, there was no correlation between bacterial growth and survival. We conclude that pneumonia defined by quantitative bacteriology is uncommon in ARDS. The potentially confounding role of broad-spectrum antibiotics should be studied further.

Pneumococcal antigen detection in bronchoalveolar lavage fluid from patients with pneumonia.

Pneumococcal pneumonia can be diagnosed by the detection of capsular antigen in sputum, serum, pleural fluid, or urine using countercurrent immunoelectrophoresis and latex agglutination. In addition, quantitative cultures of bronchoalveolar lavage (BAL) fluid are also reliable for establishing the aetiology of pneumonia. This study investigated the value of rapid detection of pneumococcal antigen in BAL fluid from patients with pneumonia. Pneumococcal antigen was detected by countercurrent immunoelectrophoresis and latex agglutination. Patients were grouped according to BAL quantitative culture results into pneumococcal pneumonia (n = 24), other known aetiology (n = 18), and unknown aetiology (n = 17). Thirteen patients with interstitial lung disease and without pneumonia served as a control group. In patients with pneumococcal pneumonia, antigen was detected by countercurrent immunoelectrophoresis in 50% and by latex agglutination in 54% of cases. In patients with pneumonia of unknown aetiology pneumococcal antigen was detected by latex agglutination in 53% of cases. Antigen was not detected in patients with pneumonia of other known aetiology or in control patients, yielding a specificity of 100%. In patients with pneumococcal pneumonia requiring fibreoptic bronchoscopy detection of pneumococcal antigen in BAL fluid may rapidly and accurately confirm the aetiology. Furthermore, in nearly half the cases of pneumonia of unknown aetiology antigen can be detected, suggesting that Streptococcus pneumoniae is a major causative agent in such patients.

Role of bronchoalveolar lavage in mechanically ventilated patients with suspected pneumonia

To determine the usefulness of samples obtained by bronchoalveolar lavage (BAL) in establishing the diagnosis of ventilator-associated pneumonia, quantitative cultures of BAL and protected specimen brush (PSB) samples obtained via fiberoptic bronchoscope were compared in 42 patients with suspected ventilator-associated pneumonia. Direct examination of BAL fluid was also used to identify cells with intracellular organisms. Ventilator-associated pneumonia was diagnosed in 18 patients; a total of 39 microorganisms were recovered from BAL fluid and 29 from PSB specimens. Cultures of 21 BAL and 23 PSB specimens were sterile. Quantitative BAL and PSB cultures coincided in 76% of cases. Sterile BAL and PSB cultures agreed in 87% of cases. Cultures were completely discordant in only three cases. The sensitivity of BAL for diagnosis of ventilator-associated pneumonia using bacterial counts of > or = 10(4) cfu/ml was 89%, and specificity was 100%. In 14 of the 18 patients with ventilator-associated pneumonia, the percentage of cells containing intracellular organisms in specimens recovered by BAL was 11.6% versus 0.45% in patients without pneumonia (p < 0.05). In the remaining four patients, all of whom had Pseudomonas aeruginosa pneumonia, no intracellular organisms could be detected. Using a cut-off point of > or = 5% of cells with intracellular organisms, the sensitivity and specificity for the early diagnosis of ventilator-associated pneumonia was 67% and 96%, respectively. The results confirm the usefulness of the quantitative BAL culture (with a cut-off at 10(4) cfu/ml) for the diagnosis of ventilator-associated pneumonia. The identification of intracellular organisms in BAL fluid is a good early indicator of pneumonia, but the sensitivity of this technique may be lower for Pseudomonas aeruginosa infections.

Quantitative culture of bronchoalveolar lavage fluid for the diagnosis of bacterial pneumonia

purpose: A prospective study to determine the usefulness of quantitative bacterial cultures of fluid obtained via fiberoptic bronchoscopy and bronchoalveolar lavage as an aid in the diagnosis of bacterial pneumonia. patients and methods: All patients undergoing fiberoptic bronchoscopy with bronchoalveolar lavage during a 6 1 2 -month period. Presence of pneumonia was determined using clinical, radiographic, laboratory, and histologic data. Quantitative bacterial cultures of bronchoalveolar lavage fluid were determined using a 1-μL culture loop. results: Quantitative bacterial cultures of bronchoalveolar lavage (BAL) fluid were sensitive and specific predictors of bacterial pneumonia. Using 10 3 colony-forming units (cfu)/mL as the threshold value for a positive culture, we determined the sensitivity and specificity to be 90% and 97%, respectively. The data were also analyzed for the subgroups of patients who were intubated or were receiving antibiotics. The sensitivity and specificity were 78% and 96% for the group of patients receiving antibiotics and 100% and 82% for the group of patients intubated for more than 24 hours at the time of BAL. Values for the area under the receiver operating characteristic curve for the 3 groups were 0.94, 0.88, and 0.96, respectively. conclusions: Quantitative bacterial cultures of BAL fluid are sensitive and specific in the diagnosis of bacterial pneumonia. The use of antibiotics at the time of BAL reduces the sensitivity of the test, and prolonged intubation reduces the specificity of the test.

Diagnostic Fiberoptic Bronchoscopy in Patients with Community-acquired Pneumonia: Comparison Between Bronchoalveolar Lavage and Telescoping Plugged Catheter Cultures

We compared the diagnostic value of quantitative cultures of bronchoalveolar lavage (BAL) and telescoping plugged catheter (TPC) samples in 40 patients with moderately severe community-acquired pneumonia (CAP). None had received antibiotics previously. BAL quantitative cultures were performed in 13 control patients without pneumonia. In 28 (70 percent) patients, TPC cultures yielded > or = 10(3) cfu/ml of a pathogenic bacterium in pure culture. In 27 of these cases and in four additional cases, BAL cultures yielded > or = 10(3) cfu/ml. BAL cultures from the control group were sterile in seven cases, yielded normal flora in three cases, and yielded microorganisms thought to be not significant in two cases. Microbiologic agreement was reached by both TPC and BAL for 32 (84 percent) of 38 microorganisms recovered. Quantitative cultures from both techniques correlated very well (r = 0.71, p < 0.0001). We conclude that both TPC and BAL have similar accuracy to determine etiologic diagnosis of CAP. There was good qualitative and quantitative agreement between both techniques.

Quantitative Culture of Bronchoalveolar Lavage from Patients with Anaerobic Lung Abscesses

The study of anaerobic infections of the lung is usually limited to the use of invasive techniques such as transtracheal aspiration (TTA) to avoid contamination by oral flora. Bronchoalveolar lavage (BAL) has been used successfully in the study of the etiology of pneumonia in immunocompromised patients. This study evaluated the role of the quantitative culture of BAL in the diagnosis of lung abscess. Four episodes of lung abscess in three patients were studied, and the results of quantitative culture of BAL were compared with those of the standard technique of TTA. Nineteen anaerobic bacterial species were recovered from the BAL fluid, all but one at concentrations greater than 10(3) cfu/ml. Culture of BAL fluid yielded 18 of 22 of the isolates cultured from TTA, including 12 of 16 of the anaerobic bacteria. This study suggests that quantitative culture of BAL fluid may be useful in the bronchoscopic evaluation of lung abscess.

Diagnosis of Ventilator-associated Pneumonia by Bacteriologic Analysis of Bronchoscopic and Nonbronchoscopic “Blind” Bronchoalveolar Lavage Fluid

Substantial efforts have been devoted to improving the means for early and accurate diagnosis of ventilator-associated (VA) pneumonia in intensive care unit (ICU) patients because of its high incidence and mortality. A good diagnostic yield has been reported from quantitative cultures of bronchoalveolar lavage (BAL) fluid or a protected specimen brush, both obtained by fiberoptic bronchoscopy. As bronchoscopy requires specific skills and is costly, we evaluated a simpler method to obtain BAL fluid, that is, by a catheter introduced blindly into the bronchial tree. Quantitative cultures from bronchoscopically sampled BAL (B-BAL) and blindly nonbronchoscopically collected BAL (NB-BAL) were assessed for sensitivity, specificity, and predictive value for the diagnosis of VA pneumonia. A total of 40 pairs of samples were examined in 28 patients requiring prolonged mechanical ventilation and presenting a high risk of developing pneumonia. For comparison with bacteriologic data we defined a clinical score for pneumonia ranging from zero to 12 using the following variables: body temperature, leukocyte count, volume and character of tracheal secretions, arterial oxygenation, chest X-ray, Gram stain, and culture of tracheal aspirate. To quantify the bacteria in BAL the bacterial index (BI) was used, defined as the sum of the logarithm of the number of bacteria cultured per milliliter of BAL fluid. A good correlation between clinical score and quantitative bacteriology was observed (r = 0.84 for B-BAL and 0.76 for NB-BAL; p less than 0.0001). Similar to studies in baboons, patients with pulmonary infection could be distinguished by a BI greater than or equal to 5 with a sensitivity of 93% and a specificity of 100% (B-BAL).(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic Value of Quantitative Cultures of Bronchoalveolar Lavage and Telescoping Plugged Catheters in Mechanically Ventilated Patients with Bacterial Pneumonia

We compared the diagnostic value of quantitative cultures of bronchoalveolar lavage (BAL) and telescoping plugged catheter (TPC) samples in 34 nonimmunocompromised, mechanically ventilated (MV) patients with suspected bacterial pneumonia. A control group of seven "noninfected" MV patients was also studied. In 92% of patients with bacterial pneumonia (32 of 34), simple endotracheal aspiration samples recovered one or more microorganisms. Both BAL and TPC samples cultured colony-forming units (cfu) greater than or equal to 10(3)/ml of one or more microorganisms in 56% (19 of 34) of patients. TPC and BAL culture results agreed on 88.5% (54 of 61) of the recovered microorganisms. Sterile TPC and BAL cultures agreed on 80% (4 of 5) of the cases. Microorganisms cultured from blood samples were also cultured from BAL and TPC specimens. Culture results from the two techniques completely disagreed in only one case (3%). In the control group, one TPC and two BAL cultures yielded microorganisms in cfu greater than or equal to 10(3)/ml. Specificities of BAL and TPC were 71 and 86%, respectively, whereas specificity of endotracheal aspiration was only 14%. Both the bacterial index obtained by TPC and BAL, as well as the quantitative cultures, correlated moderately well (r = 0.78 and 0.72, respectively, p less than 0.001 for both correlations). BAL and TPC results caused changes of antibiotic treatment in 11 of 23 survivors. Neither BAL nor TPC caused complications. Our results demonstrate that BAL and TPC diagnose bacterial pneumonia in MV patients with similar accuracy. Culture results from both techniques showed excellent qualitative and reasonable quantitative agreement.