ABSTRACT
Propionibacterium acnes is a gram-positive anaerobic bacillus and a normal inhabitant of the skin. Although it is often considered a contaminant of blood cultures, it can occasionally cause serious infections, including postoperative central nervous system infections. Here, we report the case of a 70-yr-old man who developed a large cerebral abscess caused by P. acnes 13 months after neurosurgery. Immediate gram staining of the pus from his brain revealed the presence of gram-positive coccobacilli. However, colony growth was observed only after 5 days of culture. Therefore, we performed 16S rRNA gene sequencing of the pus specimen. The isolate was identified as P. acnes. The colonies developed 9 days after the initial culture. The API Rapid ID 32A test (bioMerieux, France) was performed using a colony, but an unacceptable profile was obtained. Then, the pus was transferred into the enrichment broths of the BACTEC FX (Becton Dickinson, USA) and BacT/Alert 3D (bioMerieux, Organon Teknika, USA) systems, but only the BACTEC FX system could detect growth after 5 days. We performed 16S rRNA gene sequencing and API Rapid 32A profiling with a colony recovered from Brucella agar, which was inoculated with the microbial growth in the enrichment broth from the BACTEC FX system. The organism was identified as P. acnes by both methods. This case suggests that 16S rRNA gene sequencing may be a useful alternative for identifying slowly growing P. acnes from specimens that do not show growth after 5 days of culture.
Subject(s)
Aged , Humans , Male , Brain Abscess/diagnosis , Gram-Positive Bacterial Infections/diagnosis , Magnetic Resonance Imaging , Neurosurgical Procedures , Propionibacterium acnes/genetics , RNA, Ribosomal, 16S/chemistry , Sequence Analysis, DNA , Surgical Wound Infection/diagnosisABSTRACT
BACKGROUND: Uniplex polymerase chain reaction (PCR) for detection of bacterial and panfungal genome has been applied onto a large number of intraocular fluids facilitating management of infective endophthalmitis. AIM: To develop and apply a novel, rapid multiplex polymerase chain reaction (mPCR) to detect the presence of eubacterial, Propionibacterium acnes and panfungal genomes in intraocular fluids from patients clinically diagnosed to have infective endophthalmitis. SETTINGS AND DESIGN: Prospective study. MATERIALS AND METHODS: Conventional methods of direct microscopy by KOH/calcofluor mount, Gram's staining and culture were done on 30 (19 Aqueous humor-AH and 11 Vitreous fluid-VF) intraocular specimens and mPCR done for simultaneous detection of eubacterial, P. acnes and panfungal genomes. RESULTS: mPCR detected an infectious etiology in 18 (60%) of 30 intraocular specimens. Eubacterial genome was detected in 12 (40%) specimens, P. acnes genome in 4 (13.3%) specimens and panfungal genome in 2 (6.6%) specimens. mPCR results correlated with those of uniplex PCR. mPCR results were available within 5-6 hours after receipt of specimen, as against 8 hours required for each uniplex PCR with three separate thermalcyclers for their completion. Consumption of Taq polymerase was reduced considerably for mPCR. CONCLUSION: mPCR is a cost effective, single tube method for the simultaneous detection of eubacterial, P. acnes and panfungal genomes in intraocular specimens from patients with infective endophthalmitis. It is a more rapid procedure than uniplex PCRs and requires only a single thermalcycler.