In patients with HIV infection, non-typhoidal salmonellae are a recognised cause of bacteraemia. This association was initially demonstrated in the United States, but has more recently been found in Kenyan patients. This prompted us to review the cases of patients with enterobacteriaceae bacteraemia admitted to Parirenyatwa Hospital, Harare. Non-typhoidal salmonella bacteraemia as compared with typhoid fever was significantly more common in HIV infected patients than in non-HIV infected patients (p < 0.01). It was also a cause of bacteraemia in patients with other immuno-suppressive conditions and in some patients without identifiable risk factors.
PIP: The case notes of patients with blood cultures positive for enterobacteriaceae were examined retrospectively over a 6-month period in Parirenyatwa Hospital, Harare, Zimbabwe. Speciation was possible for Salmonella typhi and shigellae only. Nontyphoidal salmonellae were serotyped. Salmonella or shigella bacteremia was identified in 51 patients. There were 14 isolates of S. typhi, 32 isolates of nontyphoidal salmonellae, and 5 isolates of shigellae species. The case notes of 38 patients could be identified for review, and of these HIV serology was available for 15 seropositive and 15 seronegative patients. The male to female ratio was approximately 3:1 for both groups and the mean age was 29.7 +or- 21. Nontyphoidal bacteremias as compared with typhoid fever were strongly associated with HIV seropositivity [p 0.01]. 3 out of 8 HIV-negative patients with nontyphoidal bacteremia had another underlying immunosuppressive disease [2 had myeloma and 1 patient had cirrhosis with complicating hepatoma]. 2 patients with nontyphoidal bacteremia whose HIV status was unknown also had another immunosuppressing disease [acute myeloid leukemia and idiopathic pancytopenia]. 13 out of 15 HIV-positive patients showed other signs of HIV infection [oral candida, herpes zoster, persistent generalized lymphadenopathy]. 3 out of 11 patients [27%] with typhoid died, while 11 out of 27 patients [40.7%] with nontyphi bacteremia died. Most strains of S. typhimurium were included in serogroup B, which accounted for 37% of nontyphoidal isolates. Earlier studies identified invasive salmonellosis in patients with other AIDS defining diseases. In Nairobi clinical features of HIV infection were found in 64% of bacteremic HIV-positive patients, but only 28% of patients fulfilled the CDC clinical case definition for AIDS. A more recent study from Nairobi demonstrated that S. typhimurium bacteremia is a common cause of intercurrent infection in HIV-positive tuberculous patients.