Microflora of autopsy material from HIV-infected patients

Abstract

According to literature, lungs are affected in 25 – 60% of HIV-infected individuals. The most common opportunistic disease in this group of patients is pneumonia of various etiology. HIV-positive patients show a wide microbiological landscape of pneumonia pathogens.The aim of the study was to determine the structure of the microflora of autopsy material obtained from the lungs of HIV-infected patients.Methods. 83 samples of autopsy material from patients with HIV infection and 27 samples from HIV-negative patients were analyzed. The deceased were treated in the pulmonary departments of Samara with a diagnosis of community-acquired pneumonia. Due to the large variety of microorganisms recovered from the autopsy material, the microorganisms were divided into several groups: Enterobacteria, non-fermentative gram-negative bacteria, Enterococci, Staphylococci, Sterptococci, and Corynebacteria. The fungi were divided into two subgroups. The first included Candida spp., the second included other types of fungi. The tests for pneumocystis infection, Mycobacterium tuberculosis, and non-tuberculosis mycobacteria were not performed.Results. Enterobacteria were found in 39.2%, non-fermentative gram-negative bacteria – in 27.3% and Enterococci – in 19.6% of the HIV-infected patients. Staphylococcus spp. were found in 4.2%, and Corynebacteria and Streptococci in 0.7% of those patients. Candida spp. accounted for 6.3%, other fungi were found in 2.0% of cases. Enterobacteria and non-fermentative gram-negative bacteria were found in 26.2% of HIV-negative patients. Enterococcus spp. – 21.4%, Staphylococci – 7.1%, Streptococci – 2.4% of those patients. Candida spp. 16.7% were found in 16.7% of HIV-negative patients. Enterobacteria were found significantly more often in the autopsy material from HIV-infected patients. The study shows the high importance of gram-negative flora as a causative agent of infectious lesions of the lung tissue. At the same time, we statistically confirmed an increase in prevalence of Enterobacteria in HIV-positive patients. Although these pathogens are not always detected in the sputum from HIV-infected patients with bronchopulmonary disorders, they are detected only by autopsy examination of the lung tissue.Conclusion. Diagnosis and treatment of pneumonia in HIV-infected patients with severe immunodeficiency have a few specific features, such as increasing the frequency of sputum culture, reducing the number of errors at the preanalytical stage of collecting the biomaterial, ensuring proper conditions for its transportation to a bacteriological laboratory, improving the quality of analysis. The physicians should be aware of the possible detection of gram-negative flora as a causative agent of lung infections and the possible change of the causative agent.