First case of bone infection caused by Paenibacillus turicensis

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.

Type IV Pili Are a Critical Virulence Factor in Clinical Isolates of Paenibacillus thiaminolyticus

Hydrocephalus, the leading indication for childhood neurosurgery worldwide, is particularly prevalent in low- and middle-income countries. Hydrocephalus preceded by an infection, or postinfectious hydrocephalus, accounts for up to 60% of hydrocephalus in these areas. Since many children with hydrocephalus suffer poor long-term outcomes despite surgical intervention, prevention of hydrocephalus remains paramount. Our previous studies implicated a novel bacterial pathogen, Paenibacillus thiaminolyticus, as a causal agent of neonatal sepsis and postinfectious hydrocephalus in Uganda. Here, we report the isolation of three P. thiaminolyticus strains, Mbale, Mbale2, and Mbale3, from patients with postinfectious hydrocephalus. We constructed complete genome assemblies of the clinical isolates as well as the nonpathogenic P. thiaminolyticus reference strain and performed comparative genomic and proteomic analyses to identify potential virulence factors. All three isolates carry a unique beta-lactamase gene, and two of the three isolates exhibit resistance in culture to the beta-lactam antibiotics penicillin and ampicillin. In addition, a cluster of genes carried on a mobile genetic element that encodes a putative type IV pilus operon is present in all three clinical isolates but absent in the reference strain. CRISPR-mediated deletion of the gene cluster substantially reduced the virulence of the Mbale strain in mice. Comparative proteogenomic analysis identified various additional potential virulence factors likely acquired on mobile genetic elements in the virulent strains. These results provide insight into the emergence of virulence in P. thiaminolyticus and suggest avenues for the diagnosis and treatment of this novel bacterial pathogen. IMPORTANCE Postinfectious hydrocephalus, a devastating sequela of neonatal infection, is associated with increased childhood mortality and morbidity. A novel bacterial pathogen, Paenibacillus thiaminolyticus, is highly associated with postinfectious hydrocephalus in an African cohort. Whole-genome sequencing, RNA sequencing, and proteomics of clinical isolates and a reference strain in combination with CRISPR editing identified type IV pili as a critical virulence factor for P. thiaminolyticus infection. Acquisition of a type IV pilus-encoding mobile genetic element critically contributed to converting a nonpathogenic strain of P. thiaminolyticus into a pathogen capable of causing devastating diseases. Given the widespread presence of type IV pilus in pathogens, the presence of the type IV pilus operon could serve as a diagnostic and therapeutic target in P. thiaminolyticus and related bacteria.

Infected Nonunion of the Tibia Due to Paenibacillus turicensis in a Healthy Young Adult After an All-Terrain Vehicle Accident

We present the case of a 19-year-old man with an open fracture of the tibia and fibula secondary to an accident with an all-terrain vehicle. He underwent operative excisional irrigation, debridement, and fixation on the day of injury. His course was complicated by nonunion of the tibia fracture. Infection is a common factor in fracture nonunion, even in patients who receive appropriate surgical and antimicrobial management. Paenibacillus turicensis, an organism adapted to survive in the environment via spore formation, was responsible for nonunion in our patient. A brief discussion of this unusual organism, fracture nonunion, and the role of infection in etiology of nonunion follows.

Paenibacillus oralis sp. nov., Isolated from Human Subgingival Dental Plaque of Gingivitis Lesion

A Gram-stain-negative, facultative anaerobic, spore-forming, motile, and rod-shaped bacterium, strain ChDC PVNT-B20^T, was isolated from the human subgingival dental plaque of a gingivitis lesion. Phylogenetic analysis based on the 16S ribosomal RNA gene (16S rDNA) showed that the strain belonged to the genus Paenibacillus. BLAST analysis of 16S rDNA sequence of the strain displayed high identity to those of Paenibacillus faecis DSM 23593^T (97.7% similarity) and Paenibacillus macerans ATCC 8244^T (97.6% similarity). Draft genome of strain ChDC PVNT-B20^T was composed of 8,112,407 bp. The DNA G+C content of the strain was 51.3 mol%. Average nucleotide identity values between strain ChDC PVNT-B20^T and P. faecis DSM 23593^T or P. macerans ATCC 8244^T were 75.71% and 91.5%, respectively. Genome-to-genome distance values between strain ChDC PVNT-B20^T and P. faecis DSM 23593^T or P. macerans ATCC 8244^T were 21.6% (19.3-24.0%) and 44.9% (42.3-47.4%), respectively. Major cellular fatty acids of strain ChDC PVNT-B20^T were anteiso-C_15:0 (43.4%), C_16:0 (16.6%), iso-C_16:0 (14.4%), and anteiso-C_17:0 (12.4%). The sole respiratory quinone of the strain was menaqinone-7. Major polar lipids of the strain were phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), and one unidentified glycolipid (GL). Minor polar lipids were one unidentified aminolipid (AL), one unidentified phospholipid (PL), and three unidentified lipids (L1-L3). Based on these results, strain ChDC PVNT-B20^T is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus oralis sp. nov. is proposed. Type strain is ChDC PVNT-B20^T (= KCOM 3021^T = JCM 33462 ^T).

An update on the routine application of MALDI-TOF MS in clinical microbiology

Introduction: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has entered clinical diagnostics and is today a generally accepted and integral part of the workflow for microbial identification. MALDI-TOF MS identification systems received approval from national and international institutions, such as the USA-FDA, and are continuously improved and adopted to other fields like veterinary and industrial microbiology. The question is whether MALDI-TOF MS also has the potential to replace other conventional and molecular techniques operated in routine diagnostic laboratories. Areas covered: We give an overview of new advancements of mass spectral analysis in the context of microbial diagnostics. In particular, the expansion of databases to increase the range of readily identifiable bacteria and fungi, the refined discrimination of species complexes, subspecies, and types, the testing for antibiotic resistance or susceptibility, progress in sample preparation including automation, and applications of other mass spectrometry techniques are discussed. Expert opinion: Although many new approaches of MALDI-TOF MS are still in the stage of proof of principle, it is expectable that MALDI-TOF MS will expand its role in the clinical microbiology laboratory of the future. New databases, instruments and analytical software modules will continue to be developed to further improve diagnostic efficacy.