Laboratory contamination affecting orthopedic surgical management.

Bacterial contamination of pathology specimens can occur during collection, transport, or laboratory processing. Recognized sources of laboratory contamination include contamination of microscopy slides before use and contamination of reagents. We present 2 cases where contamination of glass beads used in the microbiology department as part of the tissue preparation process for urgent Gram stain led to unnecessary revision surgery. Contamination of the glass beads alone has not been cited elsewhere in the literature, and the authors feel that this needs to be brought to the attention of arthroplasty surgeons and microbiologists.

Antimicrobial prescribing in hospitals: be careful what you measure.

BACKGROUND: Measurement of prescribing is an important component of antimicrobial stewardship. The standard unit of measurement in hospitals is defined daily doses denominated by bed days (e.g. DDDs per 1000 bed days) but alternatives have not been evaluated in depth. METHODS: Electronically prescribed doses of systemic antibacterials administered in this trust during 2008 were analysed in order to generate 10 indices of antimicrobial use for each of 14 departments. These indices were five measurements of consumption (DDDs, agent days, courses, antibiotic days and treatment periods) each denominated by two measurements of activity [bed days and finished consultant episodes (FCEs)]. RESULTS: The 10 indices cluster into four groups within which they correlate well but between which correlation is poor. These four groups comprise a volume-related measurement of consumption (DDDs, agent days, antibiotic days) and an exposure-related measurement of consumption (courses, treatment periods), each denominated by either bed occupancy (bed days) or patient throughput (FCEs). CONCLUSIONS: Indices within these four groups seem to provide different and complementary information. Restricting measurement of antimicrobial use to a single metric such as DDDs per 1000 bed days may be insufficient. It is not known which (if any) of these indices are the best predictors of antimicrobial-related risks such as resistance pressure or Clostridium difficile infection.

Toward a PCR-independent molecular diagnosis of veterinary and medically relevant pathogenic organisms.

Bloodstream infections caused by bacteria and fungi are a major problem worldwide. These bloodstream infections can affect both people and livestock, placing a significant burden upon developed and developing economies. In this paper we describe a multiplexed testing format, which can identify a range of bacteria and fungi within a single blood sample. Key to this technique is the specificity and sensitivity of the nucleotide probes that capture the sample. The sensitivity and specificity of the probes may allow detection of disease-causing microorganisms without the need for polymerase chain reaction amplification if the dynamics of probe binding can be observed in real time.

Postoperative endophthalmitis caused by Sphingomonas paucimobilis.

We present a case in which a new organism, Sphingomonas paucimobilis, caused endophthalmitis after phacoemulsification in a 73-year-old woman. The case shows a recurrent acute endophthalmitis with complete resolution only after vitrectomy. This organism has not been described as a cause of endophthalmitis and was resistant to initial medical management. We also describe an interaction between this organism and a co-infective organism that may account for the unusual clinical course.

Genetic characterization of pilin glycosylation in Neisseria meningitidis.

Pili of Neisseria meningitidis are a key virulence factor, being the major adhesin of this capsulate organism and contributing to specificity for the human host. Pili are post-translationally modified by addition of an O-linked trisaccharide, Gal(beta1-4)Gal(alpha1-3)2,4-diacetimido-2,4,6-trideoxyhexose++ +. In a previous study the authors identified and characterized a gene, pglA, encoding a galactosyltransferase involved in pilin glycosylation. In this study a set of random genomic sequences from N. meningitidis strain MC58 was used to search for further genes involved in pilin glycosylation. Initially, an open reading frame was identified, and designated pglD (pilin glycosylation gene D), which was homologous to genes involved in polysaccharide biosynthesis. The region adjacent to this gene was cloned and nucleotide sequence analysis revealed two further genes, pglB and pglC, which were also homologous with genes involved in polysaccharide biosynthesis. Insertional mutations were constructed in pglB, pglC and pglD in N. meningitidis C311#3, a strain with well-defined LPS and pilin-linked glycan structures, to determine whether these genes had a role in the biosynthesis of either of these molecules. Analysis of these mutants revealed that there was no alteration in the phenotype of LPS in any of the mutant strains as judged by SDS-PAGE gel migration. In contrast, increased gel migration of the pilin subunit molecules of pglB, pglC and pglD mutants by Western analysis was observed. Pilin from each of the pglB, pglC and pglD mutants did not react with a terminal-galactose-specific stain, confirming that the gel migration differences were due to the alteration or absence of the pilin-linked trisaccharide structure in these mutants. In addition, antisera specific for the C311#3 trisaccharide failed to react with pilin from the pglB, pglC, pglD and galE mutants. Analysis of nucleotide sequence homologies has suggested specific roles for pglB, pglC and pglD in the biosynthesis of the 2,4-diacetimido-2,4,6-trideoxyhexose structure.