Non-typhoidal salmonella (NTS) bacteraemia in Malawian adults: a severe, recrudescent, HIV-associated illness.

ABSTRACT

Non-typhoidal salmonella (NTS) bacteraemia is a common, recurrent illness in HIV-infected African adults. We aimed to describe the presentation and outcome of NTS bacteraemia, the pattern of recurrence, and to determine whether recurrence results from re-infection or recrudescence. 100 consecutive adult inpatients with NTS bacteraemia in Blantyre, Malawi were treated with chloramphenicol (500mg qid for 14 days). Survivors were prospectively followed to detect bacteraemic recurrence. Index and recurrent isolates were typed by antibiogram, pulsed field gel electrophoresis and plasmid analysis to distinguish recrudescence from re-infection. Inpatient mortality was 47%, and 1-year mortality was 77%. 77/78 cases were HIV positive. Anaemia was associated with inpatient death, and several features of AIDS were associated with poor outpatient survival. Among survivors, 43% (19/44) had a first recurrence of NTS bacteraemia at 23-186 days. Among these, 26% (5/19) developed multiple recurrences up to 245 days. No recurrence was seen after 245 days, despite follow-up for up to 609 days (median 214). Suppurative infections were not found at presentation, and were only seen twice at recurrence. Index and recurrent paired isolates were identical by phenotyping and genotyping, consistent with recrudescence, rather than re-infection. NTS bacteraemia has a high mortality (47%) and recurrence rate (43%) in HIV-infected African adults. Recurrence is caused by recrudescence rather than re-infection. Since focal infections were rarely found, recrudescence may often be a consequence of intracellular tissue sequestration. There is an urgent need for improved primary treatment and secondary prophylaxis in Africa.