Background Some isolates of the Liverpool cystic fibrosis epidemic strain of Pseudomonas aeruginosa exhibit an unusual virulence-related phenotype, characterized by over-production of quorum sensing-regulated exoproducts such as pyocyanin and LasA protease. Our aim was to determine the prevalence of this unusual phenotype amongst isolates of the epidemic strain, and to study other intraclonal phenotypic and genotypic variations. Results The unusual phenotype was detected in at least one epidemic strain isolate from the majority of cystic fibrosis patients tested, and can be retained for up to seven years during chronic infection. Multiple sequential isolates of the epidemic strain taken from six patients over a period of up to nine years exhibited a wide range of phenotypes, including different antimicrobial susceptibilities. Our data suggest that each sputum sample contains a mixture of phenotypes and genotypes within the epidemic strain population, including within colony morphotypes. Many isolates exhibit premature (during early rather than late exponential growth) and over-production of pyocyanin, which has a number of toxic effects directly relevant to cystic fibrosis. Conclusion The widespread occurrence of this unusual phenotype suggests that it may play an important role in the success of the epidemic strain.

Propionibacterium avidum was isolated from bilateral breast abscesses following breast reduction surgery. This report highlights the potential pathogenicity of the normal microbial flora following surgical interventions.

The first annual report on deaths involving methicillin-resistant Staphylococcus aureus (MRSA) in England and Wales, published by the Office for National Statistics, noted a 19% increase in the number of death certificates mentioning MRSA between 2002 and 2003. 1 Deaths involving MRSA: England and Wales, 1999–2003. Health Stat Q 2005;25:60–65. Google Scholar Over the same period, however, laboratory reports of MRSA increased by only 7%, which suggests that some of the increase in inclusion of MRSA on death certificates may be due to improved levels of reporting, 1 Deaths involving MRSA: England and Wales, 1999–2003. Health Stat Q 2005;25:60–65. Google Scholar and possibly reflects the high public profile of the disease and the heightened awareness of the organism among hospital doctors. At the same time, the quality of the certification of the cause of death is often poor 2 Smith J. Medical certification of the cause of death. The Shipman inquiry. Third report. The certification and the investigation of deaths by coroners. The Stationery Office, London2003 Google Scholar and this could affect the accuracy of the reported number of MRSA deaths.

The Liverpool epidemic strain (LES) of Pseudomonas aeruginosa is a transmissible aggressive pathogen of cystic fibrosis (CF) patients. We compared transcriptome profiles of two LES isolates with each other and with a laboratory and genetic reference strain (PAO1) after growth to late exponential phase and following exposure to oxidative stress. Both LES isolates exhibited enhanced antimicrobial resistances linked to specific mutations in efflux pump genes. Although transcription of AmpC beta-lactamase was up-regulated in both, one LES isolate contained a specific mutation rendering the ampC gene untranslatable. The virulence-related quorum-sensing (QS) regulon of LES431, an isolate that caused pneumonia in the non-CF parent of a CF patient, was considerably up-regulated in comparison to either isolate LES400, associated with a chronic CF infection, or strain PAO1. Premature activation of QS genes was detected in isolates from both non-CF parents and the CF patient in a previously reported infection episode. LES isolates lacking the up-regulated QS phenotype contained different frameshift mutations in lasR. When fed to Drosophila melanogaster, isolate LES431 killed the fruit flies more readily than either isolate LES400 or strain PAO1, indicating that virulence varies intraclonally. The LES may represent a clone with enhanced virulence and antimicrobial resistance characteristics that can vary or are lost due to mutations during long-term colonization but have contributed to the successful spread of the lineage throughout the CF population of the United Kingdom.

We conducted an environmental survey in the Liverpool adult cystic fibrosis (CF) centre in order to determine the extent of environmental contamination with an epidemic strain of Pseudomonas aeruginosa that colonizes most CF patients in Liverpool, and to identify possible reservoirs and routes of cross-infection. In addition, we studied the survival of this strain on dry surfaces, compared with that of other CF P. aeruginosa strains, to explore factors that might contribute to its high transmissibility. Samples were collected from staff, patients and the environment (drains, bath tubs, showers, dry surfaces, respiratory equipment and air) in the inpatient ward and outpatient clinic. P. aeruginosa strains were tested using a new polymerase chain reaction amplification assay specific for the Liverpool epidemic strain (LES). LES was isolated from patients' hands, clothes and bed linen. Environmental contamination with LES was only detected in close proximity to colonized patients (external surfaces of their respiratory equipment, and spirometry machine tubing and chair) and was short-lived. No persistent environmental reservoirs were found. LES was detected in the majority of air samples from inside patients' rooms, the ward corridor and the outpatient clinic. Survival of LES on dry surfaces was significantly longer than that for some other strains tested, but not compared with other strains shown not to be transmissible. Improved environmental survival on its own, therefore, cannot explain the high transmissibility of this epidemic strain. Our study suggests that airborne dissemination plays a significant role in patient-to-patient spread of LES, and confirms the need to segregate those patients colonized by epidemic P. aeruginosa strains from all other CF patients.

Lemierre's syndrome is characterised by a history of recent oropharyngeal infection, clinical or radiological evidence of internal jugular vein thrombophlebitis and isolation of an anaerobic pathogen. We present a case report and review the literature.

Members of the Burkholderia cepacia complex are Gram-negative beta-proteobacteria that are classified into nine genomic species or genomovars. Some representatives of this group of bacteria, such as Burkholderia multivorans (genomovar II) and Burkholderia cenocepacia (genomovar III), are considered to be dangerous pathogens for cystic fibrosis (CF) patients because of their capacity to colonize CF lungs. The opcL gene, which encodes the peptidoglycan-associated outer-membrane lipoprotein (PAL), was detected in the genome of Burkholderia sp. LB 400 by a similarity search that was based on the sequence of the Pseudomonas aeruginosa PAL, OprL. Primers that could amplify part of opcL from B. multivorans LMG 13010(T) were designed. This PCR fragment was used as a probe for screening of a B. multivorans genomic bank, allowing cloning of the complete opcL gene. The complete opcL gene could be PCR-amplified from DNA from all genomovars. The sequences of these opcL genes showed a high degree of conservation (> 95 %) among different species of the B. cepacia complex. OpcL protein that was purified from B. multivorans LMG 13010(T) was used to generate mouse polyclonal antisera against OpcL. The OpcL protein could be produced in Escherichia coli and detected in outer-membrane fractions by Western blot. Burkholderia cells were labelled by immunofluorescence staining using antibodies against OpcL, but only after treatment with EDTA and SDS. The opcL gene could be amplified directly from the sputa of 15 CF patients who were known to be colonized by B. cepacia; sequence data derived from the amplicons identified the colonizing strains as B. cenocepacia (genomovar III, n = 14) and B. multivorans (n = 1).

Background: The Liverpool epidemic strain (LES) of Pseudomonas aeruginosa is widespread among patients with cystic fibrosis (CF) in specialist centers around Liverpool and elsewhere in the UK. This study evaluates a new diagnostic PCR assay based on a unique DNA sequence (PS21) of LES, for its identification of colonies directly from sputum. Methods: One hundred and fifty-eight sputum samples from 92 patients were cultured and P. aeruginosa isolates were typed by PS21 PCR and pulsed-field gel electrophoresis (PFGE). Subsequently, PS21 PCR was performed directly on sputum and the results were compared with culture, PFGE, and PS21 PCR typing. Results: Eighty patients were colonized with P. aeruginosa , 63 by LES (79%). There was 100% concordance between PS21 PCR on colonies and PFGE typing. The sensitivity and specificity of PS21 PCR directly on sputum was 98.2% and 93.6%, respectively. Conclusions: This study shows that PS21 PCR can be used for simple and rapid screening of LES colonization in CF patients.

Neisseria weaveri (formerly CDC [Centers for Disease Control and Prevention] group M-5 is part of the normal canine oral flora. Infections in humans are usually associated with dog bite wounds. Very rarely the organism has been isolated from sites other than wounds, or from deep seated infections. A 60-year-old man was admitted to our hospital because of an acute exacerbation of his bronchiectasis. Gram stain of bronchial washings and expectorated sputum showed numerous polymorphs and Gram-negative bacilli. Routine bacterial culture yielded a heavy pure growth of a Gram-negative rod-shaped organism that was strongly oxidase and catalase positive, indole negative, non-motile and did not ferment carbohydrates. The organism was identified as N. weaveri by using 16S rRNA sequencing. The patient was treated with a 3 weeks course of ofloxacin and had a good response. Sputum culture after treatment yielded normal respiratory flora only. To our knowledge, this is the first reported case of lower respiratory tract infection caused by N. weaveri.

ABSTRACT A multiresistant strain of Pseudomonas aeruginosa is widespread among cystic fibrosis (CF) patients attending clinics in Liverpool, United Kingdom. Suppression subtractive hybridization was used to identify sequences present in the Liverpool CF epidemic strain but absent from strain PAO1. Using dot blot and PCR amplification assays, the prevalence of such sequences among a panel of CF isolates was determined. Several sequences were found only in the Liverpool epidemic strain. Some sequences were present in the Liverpool epidemic strain and in a minority of other isolates, including sequences with homology to genes implicated in O6 serotype and siderophore production. The Liverpool epidemic strain and 81% of nonepidemic isolates contained a sequence identified as part of the PAGI-1 genomic island. Other strains implicated in epidemic spread, which were from Manchester, United Kingdom, and Melbourne, Australia, were also screened. None of the sequences identified was present in the Manchester strain. However, one of two Melbourne strains contained some of the sequences found in the Liverpool epidemic strain. All isolates implicated in epidemic spread and 76% of sporadic isolates contained the exoS gene. A sequence present in all isolates of the Liverpool epidemic strain was used to develop a diagnostic PCR test for identification of the strain from colonies or directly from sputum samples.

phenotype). Expression of MLS resistance instaphylococci is either constitutive or inducible. When it isconstitutive, bacteria exhibit resistance to all MLS anti-biotics, whereas when inducible, they are resistant to 14-membered (e.g. erythromycin) and 15-memberedmacrolides only, retaining susceptibility to 16-memberedmacrolides, lincosamides and streptogramin-B antibiotics.This dissociated resistance arises from differences in theinducing capacities of MLS antibiotics, 14- and 15-membered macrolides being better inducers than the othergroups of drugs.

Two cases of ventriculo-peritoneal (V-P) shunt infection attributable to intestinal perforation are reported. One patient developed a brain abscess, the other ventriculitis. Microbiology consisted of faecal flora and the peritoneal catheter was found to be faecally stained in both cases. There were no abdominal symptoms or signs. It is likely that infection developed via the ascending route.

The heat tolerance of 27 Enterococcus faecium isolates in water was studied. Stationary phase cultures including vancomycin resistant and sensitive clinical and food isolates were exposed to heat at 60 degrees, 65 degrees, 71 degrees, and 80 degrees C for one, three, 10, and 30 minutes and the log10 reductions in bacterial counts were determined. Exposure at 71 degrees and 80 degrees C resulted in > 6 log10 reduction in viable counts for all isolates. Seven (24%) isolates survived (< 5 log10 reduction) heat at 65 degrees C for 10 minutes. The E faecium isolates were more resistant to heat than the two E faecalis reference strains. No differences in heat tolerance were observed between vancomycin sensitive and resistant strains or between isolates of human or food origin.