Spectrum of bacterial pathogens in inflammatory and noninflammatory cutaneous ulcers of American tegumentary leishmaniasis

Abstract

Background: Cutaneous leishmaniasis (CL) ulcers exhibiting an inflammatory phenotype, characterized by purulent exudate, erythema, pain, and/or lymphatic involvement, are empirically treated with antibiotics. Objective: The spectrum of bacteria present in localized versus inflammatory phenotypes of CL is elucidated herein. Methods: Filter paper lesion impressions (FPLIs) from 39 patients with CL (19 inflammatory and 20 noninflammatory ulcers) were evaluated via real-time polymerase chain reaction (qPCR) and end-point PCR targeting: Staphylococcus aureus, Enterobacter cloacae, Streptococcus pyogenes, Enterococcus spp., Citrobacter freundii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and 16S rDNA. Whole genome sequencing (WGS) was performed on six specimens. Results: In total, 30/39 (77%) patients’ ulcers had ⩾1 bacterium detected, which included the following species: S. aureus ( n = 16, 41%), C. freundii ( n = 13, 33%), P. aeruginosa ( n = 12, 31%), E. cloacae ( n = 12, 31%), K. pneumoniae ( n = 11, 28%), Enterococcus spp. ( n = 7, 18%), E. coli ( n = 6, 15%), and S. pyogenes ( n = 4, 10). Prevalence of bacterial species did not differ by CL phenotype ( p = 0.63). However, patients with inflammatory phenotypes were, on average, over a decade older than patients with noninflammatory phenotypes (42 years vs 27 years) ( p = 0.01). The inflammatory phenotype was more prevalent among ulcers of Leishmania Viannia braziliensis (58%) and L. V. panamensis (83%) compared to those of L. V. guyanensis (20%) ( p = 0.0369). Conclusion: The distribution of flora did not differ between inflammatory and noninflammatory CL phenotypes. Further prospective analysis, including additional WGS studies of all CL ulcers for nonbacterial organisms, is necessary to determine the role of empiric antibiotic therapy in inflammatory and purulent CL.