Propionibacterium acnes Endophthalmitis Following Baerveldt Glaucoma Device Implantation

Prevalence of antimicrobial-resistant Cutibacterium isolates and development of multiplex PCR method for Cutibacterium species identification

INTRODUCTION

Cutibacterium species such as C. acnes, C. avidum, and C. granulosum are known anaerobic skin inhabitants and often cause surgical site infections. These species are genetically similar and are difficult to identify rapidly. In addition, their pathogenicity and antimicrobial resistance remain unknown. In this study, antimicrobial resistance in Cutibacterium isolates was studied and a multiplex PCR method for their identification was developed.

METHODS

A total of 497 C. acnes, 71 C. avidum, and 25 C. granulosum strains which were isolated from the acne pustule and infectious regions, were used.

RESULTS

The antimicrobial resistance rates of C. acnes, C. avidum, and C. granulosum strains isolated from patients with acne vulgaris were higher than those of strains isolated from patients with infectious diseases. In particular, macrolide-clindamycin-resistant strains were isolated most frequently from all species. Among the resistant strains, strains with 23S rRNA mutations were the most common in C. acnes (24.3%, 71/292), whereas C. avidum and C. granulosum strains were most frequently found with erm(X). For the first time, a C. granulosum strain carrying pTZC1, which codes erm(50) and tet(W), was isolated from patients with acne vulgaris. Regarding the rapid identification of causative pathogens from infectious regions, three Cutibacterium species were identified with 100% sensitivity and specificity using multiplex PCR method.

CONCLUSIONS

Our data showed that antimicrobial resistance differed among Cutibacterium species. The multiplex PCR method may contribute to the rapid detection of Cutibacterium species and selection of appropriate antimicrobial agents.

Hypopyon: Is-it Infective or Noninfective?

Hypopyon usually corresponds to the sedimentation of white blood cells, and it signifies severe intraocular inflammation. This key clinical sign may occur in association with a wide variety of infectious, inflammatory, and neoplastic conditions that may be sight- and, occasionally, life-threatening. A careful history and thorough clinical examination are the cornerstones for orienting the differential diagnosis, identifying the causative agent, and initiating prompt and appropriate treatment. This review outlines the clinical characteristics and management of hypopyon in relation with the underlying causative infectious or noninfectious ocular or systemic diseases.

Sheep as a Potential Model of Intradiscal Infection by the Bacterium Cutibacterium acnes

The anaerobic bacterium Cutibacterium acnes has been increasingly linked to the development of degenerative disc disease (DDD), although causality is yet to be conclusively proven. To better study how this organism could contribute to the aetiology of DDD, improved animal models that are more reflective of human disc anatomy, biology and mechanical properties are required. Against this background, our proof-of concept study aimed to be the first demonstration that C. acnes could be safely administered percutaneously into sheep intervertebral discs (IVDs) for in vivo study. Following our protocol, two sheep were successfully injected with a strain of C. acnes (8.3 × 10⁶ CFU/disc) previously recovered from a human degenerative disc. No adverse reactions were noted, and at one-month post inoculation all triplicate infected discs in our first animal grew C. acnes, albeit at a reduced load (5.12 × 10⁴ to 6.67 × 10⁴ CFU/disc). At six months, no growth was detected in discs from our second animal indicating bacterial clearance. This pilot study has demonstrated the feasibility of safe percutaneous injection of C. acnes into sheep IVDs under fluoroscopic guidance. The design of follow-up sheep studies to investigate the potential of C. acnes to drive pathological changes within infected discs should now be pursued.