Septic arthritis caused by a gram-negative bacterium representing a new species related to the Bordetella-Alcaligenes complex

Diversity and degradative capabilities of bacteria and fungi isolated from oil-contaminated and hydrocarbon-polluted soils in Kazakhstan

Bacteria and fungi were isolated from eight different soil samples from different regions in Kazakhstan contaminated with oil or salt or aromatic compounds. For the isolation of the organisms, we used, on the one hand, typical hydrocarbons such as the well utilizable aliphatic alkane tetradecane, the hardly degradable multiple-branched alkane pristane, and the biaromatic compound biphenyl as enrichment substrates. On the other hand, we also used oxygenated derivatives of alicyclic and monoaromatic hydrocarbons, such as cyclohexanone and p-tert-amylphenol, which are known as problematic pollutants. Seventy-nine bacterial and fungal strains were isolated, and 32 of them that were clearly able to metabolize some of these substrates, as tested by HPLC-UV/Vis and GC-MS analyses, were characterized taxonomically by DNA sequencing. Sixty-two percent of the 32 isolated strains from 14 different genera belong to well-described hydrocarbon degraders like some Rhodococci as well as Acinetobacter, Pseudomonas, Fusarium, Candida, and Yarrowia species. However, species of the bacterial genus Curtobacterium, the yeast genera Lodderomyces and Pseudozyma, as well as the filamentous fungal genera Purpureocillium and Sarocladium, which have rarely been described as hydrocarbon degrading, were isolated and shown to be efficient tetradecane degraders, mostly via monoterminal oxidation. Pristane was exclusively degraded by Rhodococcus isolates. Candida parapsilosis, Fusarium oxysporum, Fusarium solani, and Rhodotorula mucilaginosa degraded cyclohexanone, and in doing so accumulate ε-caprolactone or hexanedioic acid as metabolites. Biphenyl was transformed by Pseudomonas/Stenotrophomonas isolates. When p-tert-amylphenol was used as growth substrate, none of the isolated strains were able to use it.

Invasive Bordetella holmesii infections

Bordetella holmesii is a rare cause of invasive human disease. The fastidious and unusual nature of this organism makes routine isolation and identification challenging. We report two cases of B. holmesii bacteremia that were rapidly identified by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) when standard techniques failed to provide speciation. There are no current standards for susceptibility testing or treatment recommendations. The rare occurrence and challenges in identifying this pathogen led us to perform a comprehensive review of the epidemiology, clinical presentations, and treatment options for this potentially invasive pathogen.

Chronic laminitis is associated with potential bacterial pathogens in the laminae

A common sequella of chronic laminitis in horses is repeated abscesses with variable lameness and drainage. It is unclear whether the exudate represents the debridement phase of a non-septic inflammatory process involving clearance of laminar tissue damaged during the acute episode of laminitis, or a response to a microbial infection developed by ascent of microbes from the environment to the tissue via the white line. The objective of this study was to evaluate the possibility that an undiagnosed microbial infection in laminar tissue is present in laminar tissue collected from chronically laminitic horses without an active hoof abscess. Methods to collect laminar tissue, aseptically, from control (non-laminitic) horses and those with chronic/recurrent laminitis are described. Laminae homogenates were evaluated for the presence of bacteria. Bacteria were identified using biochemical tests and sequencing of 16S rRNA and virulence genes. Laminae from chronically laminitic horses revealed 100-fold higher levels (P=0.002) of bacteria compared to control, non-laminitic horses. Although environmental organisms were identified, potential pathogens were identified. Included were Gram positive bacteria, Brevibacterium luteolum, coagulase-negative Staphylococcus spp. as well as Gram negative bacteria, enterohemorrhagic Escherichia coli and Alcaligenes faecalis. Further research is warranted to evaluate the role of bacteria in equine chronic laminitis.

Numerical evaluation of minimal biochemical test combinations for the identification of Enterobacteriaceae species

Species identification of 572 clinical isolates of Enterobacteriaceae was determined using an in-house biochemical test panel and API 20E. The overall agreement was 82.7 per cent. When a numerical identification programme for Enterobacteriaceae was used to analyze the results of 440 E.coli isolates, the agreement with API 20E increased from 81.4 to 91.1 per cent. Numerical identification was then employed to evaluate 14 routine biochemical test panels used in 12 Swedish laboratories, and an additional 18 potential new test panel variants. The theoretical identification power of the panels was measured by a scoring system, based on simulated test results for the 14 most common species of Enterobacteriaceae. The results showed wide variations in the performance of different panels, with a number of panels being of insufficient quality. Among the 32 test panels, 6 panels indicated excellent performance. These should be further evaluated for routine laboratory performance. Numerical identification methods constitute powerful tools in the hands of the clinical microbiologist to aid in species identification as well as to analyze the quality of identification charts in use.