Endocarditis caused by anaerobic bacteria.

BACKGROUND: Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES). METHODS: We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria). RESULTS: Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%). CONCLUSION: IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms.

[Pulmonary infection caused by Rhodococcus equi in a renal transplant recipient]. / Infección pulmonar por Rhodococcus equi en un trasplantado renal.

Rhodococcus equi is a primarily pathogen in animals and it has only rarely been seen in immunocompromised humans. We describe our experience with an HIV-negative patient with a functioning renal graft under cyclosporin-azathioprine-prednisone therapy. The patient died after a two months recurrent multifocal pneumonia. The cultures from sputum and blood were negatives but R. equi was isolated from lungs in the necropsy. Most of the 41 cases we had found in the literature had AIDS or HIV infection. Six cases had a kidney graft under azathioprine-prednisone therapy. Rhodococcus equi infection may be missed in some instances due to incomplete or improper identification of the organism, that grows well in aerobic media but is usually regarded as a component of normal flora or as a contaminant. The ability of R. equi to persist in and eventually to destroy macrophages is the basis of its pathogenicity. It also explains the clinical resistance to antibiotics without intracellular activity. Rhodococcus equi infection must be suspected in immunocompromised patients with recurrent pneumonia. Correct identification and combined therapy with lipophilic antibiotics that penetrate the macrophages are necessary to prevent the high mortality of this infection.