Detection rate of pathogens from sputum, blood, and bronchoalveolar lavage fluid samples in acquired immunodeficiency syndrome patients complicated with pulmonary infection

Objective To study the detection rate of pathogens from sputum, blood, and bronchoalveolar lavage fluid (BALF) samples in acquired immunodeficiency syndrome (AIDS) patients complicated with pulmonary infection. Methods Seventy-three hospitalized AIDS patients complicated with pulmonary infection in Beijing Ditan Hospital, Capital Medical University were enrolled from February 2018 to September 2018. Blood, sputum and BALF samples were collected. Blood samples were cultured to detect anaerobic bacteria, aerobic bacteria, fungi and mycobacteria. Antigen agglutination method was applied in blood samples to detect cryptococcus neoformans. The sputum samples were tested for Mycobacterium tuberculosis by acid-fast staining and were cultured to detect bacteria and fungi. The sputum samples were observed under microscope for sporotrichosis and fungal spores. The BALF samples were cultured to detect bacteria and fungi. The BALF samples were tested for Mycobacterium tuberculosis by polymerase chain reaction amplification and acid-fast staining. Pneumocystis were detected in BALF samples by methenamine silver staining method. The BALF samples were observed under a microscope for sporotrichosis and fungal spores. The detection rate of pathogens from blood, sputum and BALF samples were compared. Chi-square test was conducted for statistical analysis. Results In 73 AIDS patients complicated with pulmonary infection, the pathogen detection rates in blood, sputum and BALF samples were 8 (11.0%), 23 (31.5%) and 48 (65.8%), respectively. The difference was statistically significant (F=48.513, P<0.01). The detection rate in BALF samples was significantly higher than that in blood or sputum samples (χ2=43.349 and 17.136, respectively, both P<0.01). The detection rate in sputum samples was significantly higher than that in blood (χ2=9.215, P<0.05). The highest detection rates of pathogens in blood, sputum and BALF samples were Talaromyces marneffei 4.1%(3), viridans group streptococci 16.4%(12) and 35.6%(26), respectively. Conclusions The detection rate of pathogens in BALF samples from AIDS patients complicated with pulmonary infection is the highest, followed by sputum and blood samples. Key words: Acquired immunodeficiency syndrome; Lung infection; Etiological diagnosis