138 Multiplex Gastrointestinal Pathogen PCR Testing in HIV/AIDS Patients: The Relationship Between Enteric Infection and CD4 T-Cell Count

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INTRODUCTION: Diarrhea is a common complication of HIV/AIDS. Although non-infectious enteropathy may be attributed to HIV infection, enteric pathogens are frequently detected in episodes of diarrhea. The objective of this study was to investigate the relationship between CD4 count and enteric infection as detected by multiplex gastrointestinal PCR stool testing in HIV/AIDS patients. METHODS: We performed a cross-sectional analysis of adult inpatients and outpatients who underwent stool testing with a FilmArray multiplex gastrointestinal pathogen PCR panel (GI PCR panel) during an acute episode of diarrhea from December 2015 to February 2019. Our primary endpoint was the detection of any enteric pathogen. Patients were stratified by the presence of HIV infection and CD4 count at time of stool testing. RESULTS: Of 80 HIV+ patients who underwent a GI PCR panel, 45 (56%) tested positive for an enteric pathogen (Table 1). HIV+ patients with CD4 counts >500 (n = 26) were more likely to have a pathogen detected (19, 73%) compared to patients with a CD4 count <200 (n = 30) consistent with AIDS (12, 40%; P = 0.03; Figure). Patients with a CD4 count between 201 and 499 (n = 24) had a positivity rate that was in between that of patients with low and high CD4 counts (14, 58%). Of 30 AIDS patients, 9 (30%) had a GI infection not detected by GI PCR including CMV, HSV, LGV, MAI, and syphilis. Among this subset of 9 AIDS patients, 4 (44%) tested negative on GI PCR. AIDS patients were less likely to be adherent to antiretroviral therapy, and more likely to be on opportunistic infection prophylaxis compared to HIV+ patients with CD4 counts >200 (P = 0.03 and P = 0.002 respectively.) Compared to patients with CD4 counts >200, those with AIDS were more likely to receive empiric antimicrobial therapy at stool testing (P < 0.001), and in the 30 days following stool testing, as likely to visit an emergency room (P = 0.24), require hospitalization (P = 0.31), or undergo endoscopic procedures for continued GI symptoms (P = 0.67). CONCLUSION: Enteric infections were common in HIV+ patients who underwent a GI PCR panel for an episode of diarrhea, with the highest proportion of positive results in patients with CD4 counts >500. Based on historical data, this rate of positivity is considerably higher than in the general population of patients with an episode of diarrhea. These data suggest that AIDS patients may be more likely to have a pathogen not included on the GI PCR panel, or a chronic cause of diarrhea such as HIV-enteropathy.