Propionibacterium acnes is a Gram-positive bacterium that forms part of the normal flora of the skin, oral cavity, large intestine, the conjunctiva and the external ear canal. Although primarily recognized for its role in acne, P. acnes is an opportunistic pathogen, causing a range of postoperative and device-related infections. These include infections of the bones and joints, mouth, eye and brain. Device-related infections include those of joint prostheses, shunts and prosthetic heart valves. P. acnes may play a role in other conditions, including inflammation of the prostate leading to cancer, SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome, sarcoidosis and sciatica. If an active role in these conditions is established there are major implications for diagnosis, treatment and protection. Genome sequencing of the organism has provided an insight into the pathogenic potential and virulence of P. acnes.

Immunofluorescence microscopy-based identification of presumptive Propionibacterium acnes isolates, using the P. acnes-specific mAb QUBPa3, revealed five organisms with an atypical cellular morphology. Unlike the coryneform morphology seen with P. acnes types I and II, these isolates exhibited long slender filaments (which formed large tangled aggregates) not previously described in P. acnes. No reaction with mAbs that label P. acnes types IA (QUBPa1) and II (QUBPa2) was observed. Nucleotide sequencing of the 16S rRNA gene (1484 bp) revealed the isolates to have between 99.8 and 99.9 % identity to the 16S rRNA gene of the P. acnes type IA, IB and II strains NCTC 737, KPA171202 and NCTC 10390, respectively. Analysis of the recA housekeeping gene (1047 bp) did reveal, however, a greater number of conserved nucleotide polymorphisms between the sequences from these isolates and those from NCTC 737 (98.9 % identity), KPA171202 (98.9 % identity) and NCTC 10390 (99.1 % identity). Phylogenetic investigations demonstrated that the isolates belong to a novel recA cluster or lineage distinct from P. acnes types I and II. We now propose this new grouping as P. acnes type III. The prevalence and clinical importance of this novel recA lineage amongst isolates of P. acnes remains to be determined. INTRODUCTIONPropionibacterium acnes belongs to the 'high GC' group of Gram-positive bacteria and is found predominately in the sebaceous gland-rich areas of the skin in adults (McGinley et al., 1978). Although traditionally considered a relatively non-pathogenic member of the resident human microbiota, an increasing number of studies have implicated P. acnes as the agent responsible for various clinical conditions and infections. In addition to its well described role in inflammatory acne (Eady & Ingham, 1994), P. acnes is emerging as an important pathogen in relation to medical implant-related infections, such as those associated with central nervous system shunts (Brook & Frazier, 1991), silicone implants (Ahn et al., 1996), and prosthetic heart valves and hip joints (Delahaye et al., 2005;Tunney et al., 1998Tunney et al., , 1999. Furthermore, P. acnes is responsible for endophthalmitis, ocular and periocular infections (Aldave et al., 1999;Clark et al., 1999;Horgan et al., 1999), as well as periodontal and dental infections (Debelian et al., 1992; LeGoff et al., 1997), and has been linked to synovitis-acnepustulosis-hyperostosis-osteitis (SAPHO) syndrome (Kotilainen et al., 1996), sarcoidosis (Eishi et al., 2002) and prostate cancer (Cohen et al., 2005). The identification of a wide range of putative virulence determinants within the recently published genome sequence of the P. acnes strain KPA17202 has further brought the pathogenic potential of this organism into focus (Bruggemann et al., 2004).Two distinct phenotypes of P. acnes (types I and II), which can be distinguished by serological agglutination tests and cell-wall sugar analysis, have been known for over 30 years (Johnson & Cummins, 1972). Additional studies have show...

Random amplification of polymorphic DNA (RAPD) was evaluated as a genotypic method for typing clinical strains of Propionibacterium acnes. RAPD can suffer from problems of reproducibility if parameters are not standardised. In this study the reaction conditions were optimised by adjusting template DNA concentration and buffer constituents. All isolates were typeable using the optimised RAPD protocol which was found to be highly discriminatory (Simpson's diversity index, 0.98) and reproducible. Typing of P. acnes by optimised RAPD is an invaluable tool for the epidemiological investigation of P. acnes for which no other widely accepted method currently exists.

No abstract

Background Coccidioidomycosis is a fungal infection endemic to the southwestern United States and regions of Latin America. Disseminated disease occurs in < 1% of cases. Septic shock is even rarer, with high mortality despite therapy. Case summary We describe two cases of coccidioidal septic shock. Both patients were older men of Filipino ancestry presenting with respiratory failure and vasopressor-dependent shock. Antifungal drugs were initiated after failure to improve with empiric antibiotics; in both, Coccidioides was isolated from respiratory cultures. Despite aggressive care, both patients ultimately died of their infections. We provide a review of the published literature on this topic. Conclusions Most of the 33 reported cases of coccidioidal septic shock occurred in men (88%) of non-white race and ethnicity (78%). The overall mortality rate was 76%. All survivors received amphotericin B as part of their treatment. Coccidioidomycosis-related septic shock is a rare disease with poor outcomes; delays in diagnosis and treatment are common. Improved diagnostic testing for coccidioidomycosis could enhance recognition of this disease in the future. Although data are limited, early treatment with amphotericin B in cases of coccidioidal septic shock may reduce mortality.