Misdiagnosed outbreak of bartonella bacilliformis in Peruvian Amazon department

Abstract

Background: In March 2013, the presence of an outbreak of Bartonella bacilliformis in the Rodriguez de Mendoza (Amazonas department, Peru) was reported. B. bacilliformis is an endemic pathogen of the Andean region, responsible for Carrion’s disease. One of the main problems of this illness is the lack of adequate technical and human resources for proper diagnosis in endemic rural areas. The objective of this study was to characterize a supposed B. bacilliformis outbreak, internationally informed in Rodriguez de Mendoza province. Methods & Materials: Fifty-three blood samples were recovered from people diagnosed with Carrion’s disease, either by optical microscopy and/or clinical manifestations. In all cases epidemiological and clinical data were recorded. The samples were cultured on Columbia Agar adding 10% of sheep blood and incubated at 28 ◦C for a period of 10 weeks. Every 14 days the plates were visually inspected to detect any bacterial growth. Additionally, the DNA was directly extracted from blood and 2 different 16S rRNA PCR schemes were used, one specific for Bartonella genus and other using universal primers. Twenty-six amplified products of universal 16S rRNA were randomly recovered and sequenced. Results: The main clinical presentations reported were headache (51%), physical discomfort (51%), chill (32%) and fever (24, 5%). Only 3 blood cultures were positive. No positive PCR was obtained when using the Bartonella specific PCR either on blood or on cultured bacteria. However, all the PCR with the universal primers were positive. The sequenced 26 (49%) samples were identified as Sphingomonas spp. being this microorganism the causative agent of this outbreak. In 17% of the cases, patients were reported to have aquatic activities. Conclusion: Several Sphingomonas spp. infections in humans have been reported, mostly limited to sporadic case reports or intra-hospitalary outbreaks, but as far as we know this is the first outbreak of Sphingomonas spp. described in a non-hospital environment. The association between 17% of patients with aquatic activities suggests that this was the most feasible transmission way. Training of health staff and development of new diagnostic able to be implemented in rural endemic areas is urgent in order to overcome wrong diagnostics and avoid wrong treatments.