Gustafson, Daniel R.

Mycoplasma hominis is a commensal in the genital tract of women and has been associated with urogenital and extragenital infections. However, central nervous system infections with this organism in adults are very rare. Here we describe the recovery of M. hominis from a brain abscess associated with a postpartum infection. Seroconversion to the isolated strain was detected by both a metabolic inhibition test and an immunoblotting assay. This case demonstrates the pathogenic potential of M. hominis and the need for rapid recognition of the organism so that appropriate chemotherapeutic intervention can occur.

Bilophila wadsworthia, a recently described anaerobic gram-negative bacillus, was isolated from blood cultures of two patients with liver abscesses. These isolates exhibited the expected phenotypic characteristics, and identification was confirmed by cell wall fatty acid analysis by gas-liquid chromatography. This is the first documentation of bacteremia due to B. wadsworthia.

ABSTRACT We describe a case of shoulder hemiarthroplasty infection with Desulfovibrio legallii . Antimicrobial susceptibilities of 36 Desulfovibrio isolates are presented. Metronidazole and carbapenems exhibited reliable activity, although piperacillin-tazobactam did not. Eleven previous cases of Desulfovibrio infection are reviewed; most arose from a gastrointestinal tract-related source.

ABSTRACT Identification of anaerobic bacteria using phenotypic methods is often time-consuming; methods such as 16S rRNA gene sequencing are costly and may not be readily available. We evaluated 253 clinical isolates of anaerobic bacteria using the Bruker MALDI Biotyper (Bruker Daltonics, Billerica, MA) matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) system with a user-supplemented database and an on-plate formic acid-based preparation method and compared results to those of conventional identification using biochemical testing or 16S rRNA gene sequencing. A total of 179 (70.8%) and 232 (91.7%) isolates were correctly identified to the species and genus levels, respectively, using manufacturer-recommended score cutoffs. MALDI-TOF MS offers a rapid, inexpensive method for identification of anaerobic bacteria.

ABSTRACTActinobaculumspecies are anaerobic Gram-positive rods that have previously been associated with urinary tract infection (UTI) in the elderly. We report 12 patients withActinobaculumbacteremia. Only 40% of blood cultures were clinically considered significant by the treating physicians, but most patients were treated for UTI, suggesting a possible urinary source of bacteremia. Clinicians should be aware of the pathogenic potential ofActinobaculumspp.

ABSTRACT Robinsoniella peoriensis is a recently described anaerobic, spore-forming, Gram-positive bacillus originally recovered from swine manure. We report four human cases in which R. peoriensis was isolated from clinical samples.

ABSTRACT We have developed a rapid real-time PCR method using fluorescence resonance energy transfer probes and the LightCycler (Roche Diagnostics), which will detect the presence of the tcdC gene of Clostridium difficile in stool samples. Our PCR method also will identify the presence of base pair deletions, one of which (18 bp) has been associated with the “epidemic” toxin-hyperproducing strains. We compared the results of this PCR with those of three C. difficile toxin-detecting enzyme immunoassays (EIAs), an EIA for the detection of glutamate dehydrogenase (GDH), and culture of C. difficile . A total of 200 stool specimens were studied by the methods under comparison. C. difficile was isolated from 49 specimens by culture, and 44 of these were confirmed as containing one of the genes associated with toxin production (“toxigenic culture”). Using toxigenic culture as the “gold standard”, the sensitivities, specificities, and positive and negative predictive values, respectively, of the assays were 48%, 98%, 88%, and 87% for the Premier toxin A and B test; 48%, 99%, 91%, and 87% for the ImmunoCard toxin A & B test; 48%, 84%, 46%, and 85% for the Xpect C. difficile toxin A/B test; 32%, 100%, 100%, and 84% for the Triage C. difficile panel (for toxin A); and 86%, 97%, 90%, and 96% for the LightCycler PCR. Thus, in comparison to the sensitivity of toxigenic culture, the sensitivities of the toxin immunoassays were unacceptably low, while the LightCycler real-time PCR assay for the detection of the tcdC gene of C. difficile is sensitive and specific.