Intraoperative diagnosis of mitral valve endocarditis secondary to Paenibacillus provencensis

Infective endocarditis caused by Paenibacillus thiaminolyticus: a case report and review of literature

Background

Paenibacillus constitutes a genus of gram-positive, facultatively anaerobic, rod-shaped bacteria that act as potentially opportunistic pathogens. With only a few documented case studies to date, Paenibacillus species are rarely the cause of a disease in humans.

Case summary

We report a case involving a 64-year-old male with known mild mitral regurgitation, who presented with fever and dyspnoea. Initially treated with empirical antibiotics, his blood cultures cultivated Paenibacillus thiaminolyticus, a previously unreported cause of endocarditis. Transoesophageal echocardiography demonstrated vegetations on the both leaflets of mitral valve along with severe mitral regurgitation, thus confirming a diagnosis of endocarditis. The patient was referred for cardiac surgery; however, the procedure was delayed due to complications related to a known hepatic cyst and additionally contraction of COVID-19 infection. The patient subsequently underwent mitral valve replacement without complications.

Discussion

Because of its rarity, guidelines to recommend specific antibiotics to treat Paenibacillus infective endocarditis are absent. To confirm the pathogen, molecular methods such as mass spectrometry or 16S rRNA sequencing are required. Early targeted antibiotic therapy and cardiac surgery are warranted to achieve good clinical outcomes.

Human Paenibacillus Infections: A Systematic Review with Comparison of Adult and Infant Cases

Neonatal infections due to Paenibacillus species have increasingly been reported over the last few years. We performed a structured literature review of human Paenibacillus infections in infants and adults to compare the epidemiology of infections between these distinct patient populations. Thirty-nine reports describing 176 infections met our inclusion criteria and were included. There were 37 Paenibacillus infections occurring in adults caused by 23 species. The clinical presentations of infections were quite variable. In contrast, infections in infants were caused by only 3 species: P. thiaminolyticus (112/139, 80%), P. alvei (2/139, 1%) and P. dendritiformis (2/139, 1%). All of the infants with Paenibacillus infection presented with a sepsis syndrome or meningitis, often complicated by extensive cerebral destruction and hydrocephalus. Outcomes were commonly poor with 17% (24/139) mortality. Cystic encephalomalacia due to brain destruction was common in both Ugandan and American cases and 92/139 (66%) required surgical management of hydrocephalus following their infection. Paenibacillus infections are likely underappreciated in infants and effective treatments are urgently needed.

Febrile sepsis: first report of human disease due to Paenibacillus silvae

Introduction

Paenibacillus species are saprophytes widely distributed in nature and rarely associated with overt human infection. Most cases have been described in people with important comorbidities and/or immunodepression. We report here what is, to the best of our knowledge, the first documented case of human disease due to Paenibacillus silvae , so far considered an exclusively environmental micro-organism.

Case presentation

A 57-year-old female patient was referred to our Unit after a 2 month history of remittent fever. Upon admission, a septic state and bacteraemia were revealed; P. sylvae was identified by 16S rRNA gene amplification and sequencing with matrix-assisted laser desorption/ionization-time of flight MS. The patient became afebrile after 9 days of antibiotic treatment and was completely cured after a 2 week regimen with intravenous amoxicillin-clavulanate plus oral doxycycline.

Conclusion

The patient did not report any previous episode of infection. Most of the well-known risk factors to Paenibacillus bacteraemia, i.e. invasive procedures, use of intravenous drugs and foreign bodies, could be excluded, although her immune system was probably impaired due to obesity and heavy smoking. We suggest that the isolation of bacteria belonging to the genus Paenibacillus should not be disregarded, since there is accumulating evidence that these organisms may cause disease even in immunocompetent subjects.

Genome sequence and description of Paenibacillus ihuae strain GD6 sp. nov., isolated from the stool of a 62-year-old Frenchman

Paenibacillus ihuae strain GD6 (=CSUR P892 = DSMZ 45751^T) is the new type strain collected from the stool of a 69-year-old Frenchman admitted to an intensive care unit and receiving a 10-day course of imipenem at the time of stool collection. This is a Gram-positive, facultative anaerobic, rod-shaped bacterium. We describe here the features of this organism, together with its complete genome sequence and annotation. The genome size is 6 719 043 bp with 49.6% G+C content and contains 6211 protein-coding and 65 sRNA genes, including four 5S rRNA genes, one 16S rRNA gene and one 23S rRNA gene.