Distribution of Pathogenic Bacteria and their Antimicrobial Drug Resistance in the Blood of Patients with HIV/AIDS at a Tertiary Hospital in Hangzhou: An Eight-Year Retrospective Study

Background: Antimicrobial drug resistance (AMR) is reaching crisis levels worldwide. Patients with HIV/AIDS face the additional challenge of blood infection by antimicrobial‑resistant bacteria. However, little information on the pathogenic bacteria distribution and AMR in the blood cultures of patients with HIV/AIDS is available. Purpose: Herein, we aimed to analyze the distribution and AMR patterns of pathogenic bacteria in blood cultures of patients with HIV/AIDS. Methods: We carried out an observational, single-center, retrospective, study of all positive blood isolates from patients with HIV/AIDS between 2013 and 2020. Results: We analyzed 472 isolates from 1864 patients: 185 isolates (39.2%) were gram‑positive, 75 isolates (15.9%) were gram-negative, and 173 isolates (36.7%) were fungi. Staphylococcus isolates were the most common gram-positive bacteria (155 (83.8%)), and Salmonella were the most common gram-negative bacteria (21 (28.0%)). Most of the fungal isolates were Penicillium marneffei (108 (62.4%).) Gram-positive bacteria had the highest resistance to penicillin (139 (86.3%) and erythromycin, 126 (78.3%). Coagulase-negative staphylococci had the highest resistance to oxacillin (77.0%), while the resistance of S. aureus only was 17.6%. Gram-negative bacteria had high resistance to ampicillin (82.1%) and ampicillin/sulbactam (57.1%). Among the fungal isolates, Cryptococcus neoformans was not resistant to amphotericin B, fluconazole, or itraconazole (sensitivity ≈ 100%). Overall, about 51% of isolates showed multidrug resistance, and there was an upward trend of antibiotic resistance in recent years. Conclusion: Positive blood culture from patients with HIV/AIDS mainly contained gram-positive organisms, followed by fungi. Patients with AIDS with lower T cells counts had a had higher risk of fungal and mycobacterial infection. Gram-positive and gram-negative bacteria had high resistance rates to first-line antibiotics. Several pathogens were multidrug resistant. Culture isolation and microbiology services with susceptibility testing remain key to protecting the HIV/AIDS population from drug-resistant bacterial infections.