Diagnosis of Pulmonary Infections in Immunocompromised Patients by Fiber-optic Bronchoscopy with Bronchoalveolar Lavage and Serology

Abstract

Fiber-optic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) were performed on 67 occasions in 57 immunocompromised patients with symptoms consistent with pulmonary infection. Diagnosis was achieved more often in renal transplant patients than in patients with hematological malignancies (85% versus 28%). Culture (bacteria, virus, fungi), staining and microscopy (bacteria, fungi, Pneumocystis carinii (PC)) and antigen detection by indirect immunofluorescence (cytomegalovirus (CMV), respiratory viruses, PC, Legionella) were used for diagnosis. On 20 occasions transbronchial biopsies with histopathologic examination were performed. In addition, serology comprising the herpes group (HHV-6) and respiratory viruses was done. A microbial diagnosis was obtained on 45% of occasions. The most common pathogens found were CMV (31%) and PC (25%). On 22 (33%) occasions a rapid diagnosis of 1 or more microbial agents was obtained within 24 h by conventional staining or indirect immunofluorescence. The clinical relevance of findings of CMV, HHV-6, and Epstein-Barr virus in BAL by polymerase chain detection on 18, 6 and 3 occasions is discussed. On 4 occasions pathogenic bacteria were found. It was not possible to relate findings of coagulase-negative staphylococci, alpha-streptococci and Candida albicans to the pulmonary infection.

Therapeutic implication of BAL in patients with neutropenia

“…The bacterial spectrum isolated in our patients corresponded to the spectrum obtained in other studies in immunocompromised host with Streptococcus and Staphylococcus species isolated most frequently [7,9,11]. Most common organisms found in immunocompromised patients by Eriksson et al [9] were alpha-hemolytic streptococci, coagulase-negative staphylococci, enterococci, and Neisseria species.…”

“…Additionally, most neutropenic patients with pneumonia receive antifungal drugs according to international guidelines [16,18,19,26]. It is known that previous antimicrobial treatment lowers the yield of BAL culture and is probably responsible for the low impact on treatment changes [4,5,7,9,30]. We could demonstrate as well, that positive bacterial BAL results were significantly less common in patients who underwent antibacterial prophylaxis than in patients who did not.…”

“…The diagnostic yield of BAL published for neutropenic patients with pneumonia ranged between 13% and 53% [3,5,9,11,21,27,30]. Nearly all of these data were collected in retrospective studies.…”

“…Samples were analyzed microscopically after staining with Gram stain and calcofluor white fluorescence stain for the detection of microorganisms. We did not focus on the evaluation of the cytologic pattern of BAL since it was shown in other investigations that the therapeutic usefulness of cytological examination was very low in hematological patients with chemotherapy and antibiotics prior to BAL [5,9]. Quantitative bacterial and fungal cultures were performed according to generally accepted methods.…”

“…It has been shown in patients with different kinds of immunosuppression that BAL may provide a diagnostic yield in 13 to 60% of cases [2,8,14,15,24,25,29]; but there exists only a few data concerning BAL in patients with pneumonia during neutropenia [3,5,9,11,21,27,30]. Maschmeyer et al [19] recommended BAL in febrile neutropenic patients not responding to empirical antimicrobial therapy, in case of positive chest radiography findings.…”