Bacterial coinfections in travelers with malaria: rationale for antibiotic therapy

Malaria predisposes children in areas where malaria is endemic to concurrent bacteremia, often with severe outcomes. The importance of bacterial coinfections in patients diagnosed with malaria in nonendemic settings has, however, not been reported. A retrospective analysis of microbiology data was performed in 755 travelers diagnosed with malaria in Sweden. Bacterial cultures from blood and other locations were correlated to clinical outcome and antibiotic treatment. Blood cultures were drawn from 417 (55%) patients (88% of whom were >15 years old), and bacterial isolates of clinical relevance (Salmonella enterica serovar Enteritidis and Escherichia coli) were detected in 2 patients (0.3%). Cultures from other locations (mainly urine, nasopharyngeal, and fecal samples) were obtained from 44% of the patients with 4.9% positivity. Of the 38 patients given antibiotics, 47% had neither severe malaria nor positive cultures and/or radiology signs indicative of treatment. C-reactive protein levels were associated with bacterial infections but had only a fair predictive value. Bacterial coinfections are uncommon among travelers with malaria. These data suggest a weaker association between malaria and bacteremia than previously described in endemic settings and might indicate different patient populations with different pathophysiological mechanisms and microbial environments. The study supports a restrictive antibiotic policy in returning travelers with malaria.