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Clinical microbiology should have a physical presence, but not necessarily on-site diagnostic laboratory facilities, in each hospital to ensure a quality laboratory-based infection service and strong professional interaction with clinicians. The adoption of industrial practices and the introduction of new costly molecular techniques raise the possibility that non-microbiological functions of laboratory management could be left to management professionals. This remains highly controversial; the advantages must be contrasted with the potential to disrupt the traditional managerial responsibility of the microbiologist and the links between the laboratory and clinical staff. Managers and healthcare professionals must resolve this issue, perhaps with the support of the ESCMID. Views varied, according to current professional arrangements and size of the laboratory and population served, on whether there should be a common laboratory for microbiology and other pathology disciplines with joint access to new high-technology techniques, or whether microbiology must continue as a separate facility. Clinical microbiology and infection control were viewed as core services that must be present even in smaller hospitals. Larger community hospitals and teaching centres require a full complement of expertise in laboratory and clinical practice. Integration of these disciplines within a department of infection is an emerging concept. A concern was the shortfall in trained expertise because of the ageing nature of current specialists. The importance of recruiting talented new graduates was emphasised. The importance of this topic led to a recommendation that an ESCMID working party be established to investigate the current arrangements of infection services in Europe and to make recommendations for the future organisation.

Biofilm-associated bacteria display a decreased susceptibility towards antibiotics. Routine assessment of antibiotic susceptibility of planktonic bacteria therefore offers an insufficient prediction of the biofilm response. In this study, in vitro biofilms of eight clinical Staphylococcus epidermidis strains were subjected to treatment with vancomycin, teicoplanin, oxacillin, rifampicin and gentamicin. In addition, the biofilms were subjected to combinations of an antibiotic with rifampicin. The effects on the biofilms were assessed by crystal violet staining to determine the total biofilm biomass, staining with XTT to determine bacterial cell viability, and microscopy. Combining these methods showed that treatment of S. epidermidis biofilms with glycopeptides increased the total biofilm biomass and that these antibiotics were not effective in killing bacteria embedded in biofilms. The decreased killing efficacy was more pronounced in biofilms produced by strains that were classified as 'strong' biofilm producers. Rifampicin, oxacillin and gentamicin effectively killed biofilm-associated bacteria of all tested strains. Combining antibiotics with rifampicin increased the killing efficacy without influencing the total biofilm biomass. When vancomycin or teicoplanin were combined with rifampicin, the increase in biofilm biomass was neutralised and also the killing efficacy was influenced in a positive way. We conclude that the combined methodology used in this study showed that glycopeptides were not effective in eradicating S. epidermidis biofilms but that combination with rifampicin improved the killing efficacy in vitro. publisher: Elsevier articletitle: Inefficacy of vancomycin and teicoplanin in eradicating and killing Staphylococcus epidermidis biofilms in vitro journaltitle: International Journal of Antimicrobial Agents articlelink: http://dx.doi.org/10.1016/j.ijantimicag.2014.11.011 content_type: article copyright: Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved. ispartof: International Journal of Antimicrobial Agents vol:45 issue:4 pages:368-75 ispartof: location:Netherlands status: published

The purpose of this investigation was to determine the proportion of influenza-like illness (ILI) attributable to specific viruses during the influenza A(H1N1)2009 pandemic and to describe the demographic and clinical characteristics of ILI due to respiratory viruses in Belgium. Nasopharyngeal swabs were collected from ILI patients by general practitioners (GPs) and paediatricians (PediSurv) and analysed for viruses. Of 139 samples collected from children

Significant differences in the sensitivity of eight frequently used qualitative urine human chorionic gonadotropin (hCG) tests in Belgium were observed in this study. Although most manufacturers claimed to detect hCG levels as low as 25 mIU/ml, only two out of six tests for home use and one out of two tests for professional use only, achieved the claimed detection limit. According to a survey, we performed among 20 acute care hospitals, 80% of the surveyed hospitals claimed to use these types of hCG analysis in a diagnostic setting. Unsatisfactory performance of these point-of-care testing (POC) assays for urinary hCG could have major consequences in a hospital setting, exposing the early pregnant woman to harmful diagnostic and therapeutic procedures. Although qualitative urine hCG tests are rapid and convenient, determination of hCG in blood remains the gold standard for the diagnosis of pregnancy.

Recently, the predation of Bdellovibrio bacteriovorus on a periodontal pathogen has been described. The current study explores the potential antimicrobial activity of a range of predatory bacteria against key periodontal pathogens. A number of representatives from the Bdellovibrio, Bacteriovorax and Peredibacter lineages (called 'BALOs') were tested for their activity towards a group of key periodontal pathogens and an optimal multiplicity of infection was established. As the oral cavity contains a wide variety of bacteria that are not preyed upon, it was investigated if they can have an effect on the predation efficiency of BALOs. It was concluded that a number of important variables involved in bacterial predation are found to be compatible with the composition of the oral microbiota. This finding makes the case for continued study of the potential for BALOs to combat periodontal pathogens.

Early in the influenza A(H1N1)2009 pandemic, children < 5 years were considered to be at increased risk of contracting the disease and developing complications [1,2]. With the start of the mitigation phase, surveillance had to be enhanced to support decision making and several surveillance systems were reinforced, adapted or set up. The paediatric outpatient population was thought to be insufficiently covered by the Sentinel General Practitioners (SGP) network for children < 5 years [3] and the consultation behaviour of young children's parents could not be predicted during the pandemic. Therefore surveillance of influenza-like illness (ILI) in outpatient children was launched by extending the surveillance scope of the already existing Paediatric Surveillance Network (PediSurv). This network consists of about 440 voluntary participating paediatricians and about 350 GPs in Brussels. It was set up as part of the epidemiological surveillance of communicable diseases in Europe and in the framework of polio eradication and measles elimination [4,5]. Currently, PediSurv monitors the occurrence of acute flaccid paralysis, measles, mumps, Invasive Pneumococcal Disease (IPD), congenital rubella and haemolytic uremic syndrome. Although PediSurv is not an exhaustive surveillance system and calculation of incidence is not possible for all diseases, the stable participation rate allowed to observe trends and to detect clusters and outbreaks [6,7]. This article describes how we introduced clinical and virological surveillance activities of in-fluenza within this surveillance system and presents the results from week 39 until week 53 of 2009.

Introduction/Background Documentation of the International Classification of Functioning, Disability and Health (ICF) components in physiotherapeutic electronic health records may improve interdisciplinary productivity and efficiency We examine the effect of targeted teaching and personalized feedback on physiotherapists’ completion of physiotherapeutic patient records and description of these components. Material and method A randomized controlled trial in a tertiary care hospital in Belgium Ten physiotherapists were included in the intervention group and five physiotherapists were in the control group The intervention (2015–2016) included targeted teaching and weekly personalized feedback for a period of four weeks regarding reporting of ICF components in electronic patient records At baseline, after targeted training, after each round of personalized feedback, and at long-term follow-up, electronic patient records for 10 random patients per physiotherapist in the intervention group were reviewed for completion of a physiotherapeutic patient record and reporting of ICF components Data for the control group were collected at baseline, after the third round of feedback, and at long term follow-up 670 and 140 patient records from 729 unique patients were reviewed for the intervention and control group, respectively. Results In the intervention group, all outcomes improved (Table 1 and Fig. 1) Although reporting declined for several components between personalized feedback and at long-term follow-up, at both occasions patient record completion and reporting of ICF components of activity, participation, and personal factors were significantly higher compared to the control group For environmental factors, the significant effect after personalized feedback disappeared at long-term follow-up Reporting of body functions and structures improved similarly across groups. Conclusion Targeted teaching and personalized feedback improved completion of physiotherapeutic patient records and reporting of ICF components Intervention strategies should factor in regular reminders to ensure continued reporting of ICF components in the long term.

Quantification of Bdellovibrio-and-like organisms (BALOs) by microbial culturing has a number of substantial drawbacks. Therefore a quantitative PCR (qPCR) assay was designed for the culture-independent enumeration of the Bdellovibrionaceae. After optimization, the dynamic range of the qPCR assay was assessed, the specificity was evaluated and a comparison with quantitative microbial culturing was made. To evaluate the suitability of the qPCR assay for analysing environmental samples, fresh water samples were investigated by microbial culturing and by the qPCR assay. The results revealed a substantial difference between the two techniques and indicate that most Bdellovibrionaceae cells are left undetected in environmental samples when only current microbial culturing techniques are used. The application of this new technique is therefore likely to confirm the hitherto underestimated sizes and roles of predatory bacterial populations in nature. ispartof: Environmental microbiology reports vol:1 issue:4 pages:228-233 ispartof: location:United States status: published

A challenge panel of bacterial strains useful for clinical laboratories to validate their European Committee on Antimicrobial Susceptibility Testing (EUCAST) antimicrobial susceptibility test (AST) system was established. A total of 117 strains, obtained from Belgian Reference Centres (n = 57) and from routine clinical samples (n = 60) was selected based on resistance pattern. These strains were analysed in seven different laboratories by three different automated AST systems (Vitek (n = 2), Phoenix (n = 2) and Microscan (n = 2)) and by disc diffusion from five different manufacturers (Rosco (n = 2), Becton-Dickinson (n = 2), Biomerieux (n = 1), Bio-rad (n = 1) and i2a (n = 1)). To select the challenge panel, selection criteria were set for categorical agreement between the different systems and the number of very major errors, major errors and minor errors. Very major and major errors for at least two antibiotics were observed in 43% of all strains, leading to the exclusion of these strains from the selected panel. In only 10% of all tested strains was there 100% categorical agreement for all antibiotics. Finally, 28 strains (14 Gram-positive and 14 Gram-negative) covering a wide spectrum of resistance mechanisms were selected. Pilot-testing of this challenge panel in 20 laboratories mainly confirmed the results of the validation study. Only six strains withheld for the pilot study could not be used as challenge strain due to an overall (very) major error rate of >5% for a particular antibiotic (n = 5) or for two antibiotics (n = 1). To conclude, this challenge panel should facilitate the implementation and use of EUCAST breakpoints in laboratories. S. Desmet, (C) 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

The complexity of the periodontal microbiota resembles that of the gastro-intestinal tract, where infectious diseases are treatable via probiotics. In the oro-pharyngeal region, probiotic or replacement therapies have shown some benefit in the prevention of dental caries, otitis media, and pharyngitis, but their effectiveness in the treatment of periodontitis is unknown. Therefore, this study addressed the hypothesis that the application of selected beneficial bacteria, as an adjunct to scaling and root planing, would inhibit the periodontopathogen recolonization of periodontal pockets. Analysis of the data showed, in a beagle dog model, that when beneficial bacteria were applied in periodontal pockets adjunctively after root planing, subgingival recolonization of periodontopathogens was delayed and reduced, as was the degree of inflammation, at a clinically significant level. The study confirmed the hypothesis and provides a proof of concept for a guided pocket recolonization (GPR) approach in the treatment of periodontitis. ispartof: Journal of Dental Research vol:86 issue:11 pages:1078-1082 ispartof: location:United States status: published

Pseudomonas aeruginosa is a major cause of nosocomial infections. Due to its genetic plasticity, it can adapt to a wide variety of environments, causing infections in almost all body sites (with however a predilection for the respiratory tract, especially in cystic fibrosis patients). It also shows a remarkable capacity to resist to antibiotics, either intrinsically (through constitutive expression of β-lactamases and efflux pumps, or low permeability of the outer membrane), or upon exposure to antibiotics through acquisition of resistance genes (coding fo antibiotic-degrading enzymes inactivating or target modifications), overexpression of efflux pumps, decreased expression of porins, or target mutations. Worryingly also, these mechanisms are often present simultaneously, conferring multiresistant phenotypes. Susceptibility testing is therefore crucial in clinical practice. Empiric treatment is usually initiated using a bitherapy, selected based on local epidemiology (β-lactam plus aminoglycoside or fluoroquinolone). However, it should be streamlined as soon as possible, based on susceptibility data and patient’s evolution. Alternative drugs (colistin, e.g.) have proven useful for multiresistant strains. Innovative therapeutic options for the future remain scarce, while attempts to develop vaccines have been so far unsuccessful. Among broad-spectrum antibiotics in development, ceftobiprole, sitafloxacin and doripenem show interesting in vitro activity. The two first molecules, however, are evaluated in the clinics towards Gram-positive only. Pump inhibitors are under study but proved much more difficult to develop than originally anticipated. Therefore, selecting appropriate antibiotics and optimizing their use based on pharmacodynamic concepts remains the only way to cope with pseudomonal infections.

Adherence of Actinobacillus actinomycetemcomitans to epithelial cells is an important step in periodontal disease pathogenesis. Recent publications describe the subgingival presence of a wide array of viruses [e.g., human cytomegalo-virus (hCMV)]. Since viruses can increase cellular susceptibility for bacterial adherence, we investigated whether hCMV renders epithelial cells more prone to adherence by Actinobacillus actinomycetemcomitans. Cultivated HeLa and primary epithelial cells were shown to be semi-permissive for hCMV infection, which resulted in increased bacterial adherence. This increase correlated with viral concentrations, was evident in all Actinobacillus actinomycetemcomitans strains examined, and increased during the first 24 hrs, followed by a slight decrease. Immediate early antigen expression was not correlated with the increased adherence of Actinobacillus actinomycetemcomitans. The results confirmed our hypothesis that the adherence of Actinobacillus actinomycetemcomitans is influenced by hCMV in vitro. ispartof: Journal of Dental Research vol:86 issue:2 pages:175-180 ispartof: location:United States status: published

The performance of the m 1000 system (Abbott Laboratories, Illinois) as a front-end extraction system for high-throughput “in-house” quantitative real-time PCR assays was analyzed and compared to that of manual extraction of plasma and serum samples (hepatitis C virus [HCV] and hepatitis B virus [HBV]) and EDTA-blood samples (cytomegalovirus [CMV] and Epstein-Barr virus [EBV]). Linearity of extraction was tested on dilution series of HCV and HBV reference materials. The correlation coefficient for standard curves based on repeated extraction runs was 0.97 ± 0.06 for HCV and 0.97 ± 0.03 for HBV, indicating a linear extraction from 100 to 1.0 × 10 5 HCV IU/ml and from 100 to 1.0 × 10 6 HBV IU/ml. Intra- and interrun variability was below 0.23 log 10 IU/ml for 2.98 to 5.28 log 10 HCV IU/ml and 2.70 to 5.20 log 10 HBV IU/ml. Correlation between automated and manual extraction was very good. For HCV, the correlation coefficient was 0.91 and the mean difference in viral load was 0.13 log 10 HCV IU/ml. For HBV, the correlation coefficient was 0.98 and the mean difference in viral load 0.61 log 10 HBV IU/ml. For CMV and EBV, the correlation coefficient was 0.98 and the mean difference in viral load 0.33 log 10 copies/ml. Accuracy was confirmed with a reference panel (QCMD, Glasgow, Scotland) for all four assays. No cross-contamination was observed when extracting strongly positive polyomavirus samples (8.10 log 10 copies/ml) interspersed with polyomavirus-negative samples. Automated extraction via the m 1000 system offers a high reliability of extraction and resulted in a strong reduction of the required extraction hands-on time for high-throughput PCR compared to manual extraction protocols.

We report a case of cryptococcal meningitis in an immunocompetent female patient with exposure to a pet magpie (Pica pica). Genetically indistinguishable isolates were cultured from the cerebrospinal fluid of the patient and excreta of the bird. Our data strongly suggest zoonotic transmission of Cryptococcus neoformans var. grubii from a magpie to this patient.

Clinical microbiologists and microbiology laboratories are experiencing changes due to evolving views on ‘healthcare delivery’ as an economic activity, due to changes in the medical environment and the demographics of the workforce, and technical evolution. Cost-effectiveness of laboratory procedures has been achieved through consolidation and integration of laboratories. Consolidation offers economy of scale and reduction in numbers of on-site staff, but also leads to separation of microbiologists from their clinical colleagues. Integration puts different laboratory disciplines under a single management, and leads to reorganisation of laboratories along common work-lines. Cost-savings combined with on-site availability of laboratories are achieved at the expense of a reduction in the influence of microbiologists in the daily running of the laboratory. Medically, there is growing emphasis on evidence-based diagnostics. Because of time-delays inherent in culturing, microbiology has a limited impact on patient outcomes. Increased clinical relevance of microbiological testing through rapid testing is mandatory. There is an increasing shortage in Europe and the USA of trained microbiology laboratory technicians and microbiologists. This reinforces the trend towards more automation and integration. Technological advances, particularly in molecular diagnostics, offer the possibility of rapid reporting and improvement of the impact of clinical microbiology on patient management. Molecular tests, however, fit perfectly the concept of an integrated laboratory and may further loosen the link between microbiologist and microbiology tests. The challenge for clinical microbiology will be to use new techniques to improve its cost-effectiveness and impact on infectious disease management. The future organisation of microbiology laboratories must support this but is itself of secondary importance. The training of future microbiologists must prepare them for this changing environment.

Objectives:Porphyromonas gingivalis, one of the key pathogens in the development of periodontitis, produces a number of virulence factors that might explain its pathogenicity. One of them is the ability to adhere and invade pocket epithelium. The aim of this study was to follow, over time, the association of P. gingivalis and consequent morphological changes of the pocket epithelium cells. Material and Methods: The association capacity of four P. gingivalis serotypes [K1, K2, K4, K- (nonencapsulated)] with in vitro cultured mono-layers from periodontal pocket epithelial cells of patients with periodontitis, was followed by fluorescence microscopy and bacterial culture. The contact time between bacteria and epithelium cells ranged from 45 min to 8 h. The microscopic evaluation allowed differentiation between dead and living cells (bacteria as well as epithelium) and description of the morphological changes after association. Results: A highly significant difference in the number of associating bacteria was found between dead and living epithelium cells, and between non-capsulated and capsulated strains. A significant increase in the proportion of dead pocket epithelium cells was found with prolonged association time. The morphological changes (rounding of the epithelial cell, detachment from the glass cover-slip and loss of intercellular contact) occurred faster for mono-layers inoculated with the non-encapsulated P. gingivalis strain. Conclusions: This study indicates that dead pocket epithelium cells harbor more P. gingivalis cells, and that a positive correlation exists between contact time and cell death. For the P. ginigvalis species, non-encapsulated strains associate in higher number. As a result, the damage they cause to the host cell seems to occur faster than occurs in encapsulated strains. As such, cell death can be seen as the end-result of bacterial association.

Interpretive reading analyses the complete resistance profiles of bacteria to multiple antibiotics and infers the resistance mechanisms present; it aids therapeutic choice and enhances surveillance data. We evaluated the Advanced Expert System (AES), which interprets MICs generated by the VITEK 2. Ten European laboratories tested 42 reference strains and 76-106 of their own strains, representing important resistance genotypes. Interpretive reading by the VITEK 2 AES achieved full agreement with genotype data for 88-89% of strains, with the correct mechanism identified as one of two possibilities for a further 5-6%. Mechanisms inferred with 90% agreement with reference data included methicillin resistance in staphylococci, glycopeptide resistance in enterococci, quinolone resistance in staphylococci and Enterobacteriaceae, AAC(6')-APH(2")-mediated aminoglycoside resistance in Gram-positive cocci, erm-mediated macrolide resistance in pneumococci, extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae and Pseudomonas aeruginosa, and acquired penicillinases in Enterobacteriaceae. VanA, VanB and VanC phenotypes of enterococci were distinguished reliably, and ESBL production was accurately inferred in AmpC-inducible species as well as Escherichia coli and Klebsiella spp. Mechanisms identified, but only as possibilities among several, included IRT-type beta-lactamases and individual aminoglycoside-modifying enzymes in Enterobacteriaceae. Most disagreements with reference data concerned pneumococci found to have high-level penicillin resistance by the VITEK 2 AES but previously determined, phenotypically, to have intermediate resistance. When ESBL production was inferred in E. coli and klebsiellae, the VITEK 2 AES edited susceptible results for cephalosporins (except cefoxitin) to resistant; when an acquired penicillinase was inferred in Enterobacteriaceae, piperacillin results were edited to resistant; and when staphylococci were found methicillin resistant, resistance was reported for all beta-lactams. Further editing may be desirable (e.g. of cephalosporin results for salmonellas inferred to have ESBLs).

The aims of the present study were (i) to develop and test a sensitive and reproducible method for the study of gene expression in staphylococci and (ii) to study the expression of five housekeeping genes which are involved in nucleic acid metabolism ( gmk , guanylate kinase; the dihydrofolate reductase [DHFR] gene), glucose metabolism ( tpi , triosephosphate isomerase), and protein metabolism (the 16S rRNA gene; hsp-60 , heat-shock protein 60) during in vitro exponential and stationary growth. A modified method for instant mRNA isolation was combined with gene quantification via Taqman real-time quantitative PCR. The detection limit of our method was 10 copies of RNA. The average intersample variability was 16%. A 10-fold increase in the expression of the hsp-60 gene was induced by exposure to a 10°C heat shock (37 to 47°C) for 10 min. During in vitro growth, the expression of all five housekeeping genes showed rapid up-regulation after inoculation of the bacteria in brain heart infusion medum and started to decline during the mid-exponential-growth phase. Maximal gene expression was 110- to 300-fold higher than gene expression during stationary phase. This indicates that housekeeping metabolism is a very dynamic process that is extremely capable of adapting to different growth conditions. Expression of the 16S rRNA gene decreases significantly earlier than that of other housekeeping genes. This confirms earlier findings for Escherichia coli that a decline in bacterial ribosomal content (measured by 16S rRNA gene expression) precedes the decline in protein synthesis (measured by mRNA expression).

During a 4-month period we prospectively investigated the frequency of polyclonal catheter infections with Staphylococcus epidermidis. Of each catheter with pure growth of S. epidermidis, six colonies were genotypically analyzed with pulsed-field gel electrophoresis. Two out of 12 patients with catheter infection had a polyclonal infection. Both clones of each catheter had a clearly different antibiotic susceptibility. This study shows that polyclonal catheter infections are not exceptional. Further studies are needed to define the clinical consequences of polyclonal catheter infection.

Objectives: To examine whether urgent orotracheal intubation (OI) can induce bacteremia. To find predictive factors for post-intubation bacteremia. Design: Prospective observational study. Setting: Seventeen-bed medical intensive care unit in a university hospital. Patients: Sixty-eight adult intensive care patients undergoing urgent OI. Measurements and results: Patients in need of OI could be included if no cardiopulmonary resuscitation was performed. A blood culture was taken immediately before, as soon as possible after, and 60 min after intubation. The indication for intubation, ease of intubation, and the antibiotics used before intubation were registered. Six patients (6/68 or 9%) had streptococcal bacteremia immediately (mean 10.8 min) after intubation. No patient (0/62) had streptococcal bacteremia 60 min after intubation (P = 0.01). Four of the six patients showing streptococcal bacteremia after intubation were intubated by a second doctor because of difficulties during intubation, whereas this was the case in only 9/62 in those without streptococcal bacteremia (P = 0.01). Four of the 13 patients (31%) who needed to be intubated by a second doctor showed transient streptococcal bacteremia. Of the 20 patients not receiving antibiotics at the time of intubation, four (20%) had streptococcal bacteremia compared with 2/47 (4.2%) patients receiving antibiotics (P = 0.06). Conclusions: Urgent intubation can cause transient bacteremia with streptococci in a significant proportion of intensive care patients. The observed frequency of bacteremia is higher than previously reported after elective intubation. The difficulty of intubation is probably a predisposing factor.

Foreign body infections by coagulase negative Staphylococci are an important and growing problem in our hospitals. Only recently have we started to get some data on the specific virulence factors that permit the otherwise non-pathogenic Coagulase Negative Staphylococci (CNS) to be so successful in causing foreign body infections. Adherence of the Coagulase Negative Staphylococci to the foreign body is a first and crucial step. Several genes and gene-products have been identified that enhance staphylococcal adherence to biomaterials. Adherence is followed by accumulation; in this phase the Coagulase negative Staphylococci organise themselves into a complex multilayer of cells covered with polysaccharide. This we call the biofilm. Finally coagulase negative Staphylococci undergo complex and as yet non-defined metabolic changes that in combination with biofilm formation allow them to persist on the foreign body and become less susceptible to antibiotics. Few data are available on the factors involved in the accumulation and persistence phase.

Forty-three methicillin-resistant Staphylococcus aureus (MRSA) isolates with known genetic and epidemiological relatedness and different degrees of transmission were analyzed by antibiotyping, protein A gene polymorphism analysis, and coagulase gene polymorphism analysis. The three typing systems were evaluated for their performance and convenience to define clones and to discriminate between epidemic MRSA (EMRSA) and sporadic MRSA (SMRSA). Antibiotyping and AluI restriction fragment length polymorphism analysis of the coagulase gene were able to define clones in the same way as DNA macrorestriction analysis (SmaI). However, both techniques presented disadvantages, making neither of them useful as a single typing method. Protein A gene polymorphism analysis appeared to be of no value for clonal analysis. None of the three typing methods was able to differentiate between EMRSA and SMRSA.

Imported vs. hospital-acquisition of MRSA was assessed in > 6000 patients at a large tertiary care teaching hospital. About five percent (5·1%) of patients carried MRSA on admission, mostly without clinical symptoms; the highest percentage (11·6%) being in geriatric patients. Hospital-acquisition of MRSA occurred in 1·7% of patients and was particularly high in intensive-care units (5·2%). Phenotype and genotype analysis of 158 MRSA strains isolated from 61 patients revealed a cluster of closely related strains in the hospital-acquired MRSA infections and the close relationship of this cluster to the regional epidemic MRSA strain. The MRSA strains imported by geriatric patients were genetically different, did not spread between geriatric patients and were only a minor source of nosocomial infection.

Of 233 erythromycin-resistant pneumococcal isolates collected in Belgium in 1999–2000, 89.7% carried the erm (B) gene, 6% the mef (A) gene, and 3.5% erm (B) plus mef (A). Two isolates contained neither erm (B) nor mef (A); one contained an erm (A) subclass erm (TR) gene, while the other contained an A2058G mutation in domain V of the 23S rRNA gene. Of 209 erm (B)-positive isolates, 191 had clindamycin MICs > 16 mg/L and 18 had MICs ≤ 16 mg/L. Mef (A)-positive isolates all displayed the M resistance phenotype. Telithromycin remained active against erythromycin-resistant isolates, with the highest telithromycin MIC 50 being found in mef (A)-positive isolates. No difference in the prevalence of different resistance mechanisms was observed compared to isolates collected in 1995–1997.

A comparative study of fluconazole and amphotericin B susceptibility testing was performed with 68 clinical Candida species isolates and three test methods. The methods used were an agar diffusion method (E-test) and two broth dilution methods, the National Committee for Clinical Laboratory Standards (NCCLS) reference broth macrodilution method and an in-house-prepared semiautomated broth microdilution method based on the Bioscreen turbidometer. In the microdilution method, growth of the yeasts was measured continuously by the automatic turbidometer (Bioscreen), which permitted precise and objective determination of endpoints. MIC endpoints were read after 24 h for the microdilution method and the E-test. Amphotericin B susceptibility testing with the NCCLS method and the E-test yielded comparable results in 89% of the tests, meaning that the endpoints obtained were identical or differed by no more than 2 twofold dilutions. The NCCLS and broth microdilution tests scored 97% comparable results, and the E-test and the broth microdilution test yielded 90% comparable results. Fluconazole susceptibility testing produced 96% comparable results with the NCCLS test and the E-test, 100% comparable results with the NCCLS and the microdilution methods, and 98.5% comparable results with the microdilution method and the E-test. We conclude that the E-test and the Bioscreen microdilution method are valuable alternatives to the NCCLS reference method for routine susceptibility testing of Candida species with fluconazole and amphotericin B.

Recently, the predation of Bdellovibrio bacteriovorus on a periodontal pathogen has been described. The current study explores the potential antimicrobial activity of a range of predatory bacteria against key periodontal pathogens. A number of representatives from the Bdellovibrio, Bacteriovorax and Peredibacter lineages (called 'BALOs') were tested for their activity towards a group of key periodontal pathogens and an optimal multiplicity of infection was established. As the oral cavity contains a wide variety of bacteria that are not preyed upon, it was investigated if they can have an effect on the predation efficiency of BALOs. It was concluded that a number of important variables involved in bacterial predation are found to be compatible with the composition of the oral microbiota. This finding makes the case for continued study of the potential for BALOs to combat periodontal pathogens.

Objectives To investigate the presence of extended-spectrum beta-lactamases (ESBLs) among Pseudomonas aeruginosa clinical isolates referred to two Belgian reference laboratories. Methods Antibiograms were analysed for P. aeruginosa isolates referred between 2004 and 2008. Isolates resistant to ceftazidime (MIC > 8 mg/L) and with a positive double-disc synergy test between ceftazidime and clavulanate were serotyped and screened for the presence of ESBL-encoding genes. Genes encoding metallo-beta-lactamases (bla(MBL)) were sought by PCR in ESBL-producing isolates with positive imipenem/EDTA synergy tests. PFGE of SpeI-digested genomic DNA was used to compare isolates and selected strains were characterized by multilocus sequence typing. Results Forty-eight (2.2%) of 2150 P. aeruginosa isolates were confirmed as class A ESBL-producing isolates by molecular testing. bla(BEL) and bla(PER) alleles were detected, respectively, in 39 and 10 P. aeruginosa isolates originating from 16 hospitals (two isolates were simultaneously positive for BEL and PER). Fifteen of the isolates were found to co-produce ESBLs and VIM carbapenemases. These strains were pan-resistant and remained susceptible only to colistin (MICs

INTRODUCTION: Microbial interactions are considered to be important for bacterial colonization. Interactions that inhibit colonization of pathogens could possibly be used as a new treatment approach for periodontitis. The aim of this study was to test this hypothesis on soft surfaces in vitro, taking into account the hydrodynamic forces continuously present in vivo. METHODS: Cultured epithelial cells were precolonized with Streptococcus sanguinis KTH-4, Streptococcus cristatus CC5A, Streptococcus salivarius TOVE and Streptococcus mitis BMS before Aggregatibacter actinomycetemcomitans colonization. Experiments were performed in a modified Robbins-device-type flow cell. Bacterial colonization and the number of epithelial cells were evaluated by microbial culturing and quantitative polymerase chain reaction. RESULTS: The streptococci were able to inhibit A. actinomycetemcomitans colonization on soft tissue surfaces under flow conditions. Statistically significant differences were found between streptococcal pretreatments and the controls, with the most pronounced effect caused by S. sanguinis. CONCLUSION: These data confirm the possibility of applying beneficial bacteria in periodontal treatment. ispartof: Oral Microbiology and Immunology vol:24 issue:5 pages:390-5 ispartof: location:Denmark status: published

Objectives. - The aim of the study was to evaluate the antibiotic resistance in noninvasive clinical isolates of Streptococcus pneumoniae collected in Belgium during winter 2008-2007. Method. - Four hundred and forty eight unduplicated isolates collected by 15 laboratories were tested by microdilution following CLSI. Results. - Insusceptibility rates (I + R) were as follows: penicillin G (PEN) 11.6% (4.0% R), ampicillin 11.4% (4.0% R), amoxicillin + /-clavulanic acid 0, cefaclor 10.3% (9.6% R), cefuroxime 9.2% (8.7% R), cefuroxime-axetil 8.7% (7.8% R), cefotaxime, ceftazidime and cefepime 2.0% (0% R), imipenem 2.5% (0% R), ciprofloxacin and ofloxacin 5.1% (0.4% R), levofloxacin 0.7% (0.4% R), moxifloxacin 0.4% (0.2% R), erythromycin (ERY) 29.7% (29.2% R), azithromycin 29.7% (28.8% R), telithromycin 0%, clindamycin 26.3% (25.4% R) and tetracycline (TET) 21.9% (16.5% R). From 2001 to 2008, a significant decrease in penicillinin-susceptibility (21.0% to 11.6%). penicillin-resistance (9.7% to 4.0%) and ciprofloxacin-insusceptibility (11.2% to 5.1%) was found. Cross-resistance between penicillin and other betalactams in penicillin-insusceptible isolates was incomplete: all these isolates remained fully susceptible to amoxicillin. Erythromycin-insusceptibility was significantly higher in children than in adults (43.9%/27.4%), while penicillin-insusceptibility significantly higher in Brussels than in the Flanders (22.9%/8.1%). The commonest resistance phenotype was ERY-TET (12.7%) followed by ERY (7.4%) and PEN-ERY-TET (5.8%). Capsular types 19(25%), 14(19.3%), 23 (15.4%) and 15 (13.5%) were the most important in penicillin-insusceptible. Conclusion. - We noted a decrease in resistance to the majority of the compounds. Insusceptibility rates were higher in children than in adults and the difference between the north and the south of Belgium became less marked. (C) 2009 Elsevier Masson SAS. All rights reserved.

Periodontitis is a polymicrobial infectious disease primarily associated with Gram-negative periodontopathogens. Bdellovibrio and like organisms are predatory bacteria that feed on Gram-negative bacteria. This study investigated whether predatory bacteria can attack Aggregatibacter actinomycetemcomitans. Therefore, A. actinomycetemcomitans was challenged with the predator Bdellovibrio bacteriovorus under conditions simulating the oral cavity. The reduction of planktonic A. actinomycetemcomitans was quantified via bacterial culture, and the development of predatory bacteria was monitored with quantitative real-time PCR. The destruction of A. actinomycetemcomitans biofilms by B. bacteriovorus was quantified by crystal violet staining and visualized by scanning electron microscopy. The in vitro results show that B. bacteriovorus can attack, prey on, and kill A. actinomycetemcomitans and suggest a potential for B. bacteriovorus as a living antibiotic for the prevention and treatment of periodontitis. ispartof: Journal of Dental Research vol:88 issue:2 pages:182-186 ispartof: location:United States status: published

The strictly anaerobic intestinal Peptococcus niger H4 synthesizes three different steroidsulfatase enzymes: a constitutive arylsulfatase and two inducible alkylsteroidsulfatases. The arylsulfatase desulfates estrogen-3-sulfates and phenylsulfates. The two alkylsteroidsulfatases desulfate, respectively, 3 alpha-sulfates and 3 beta-sulfates of delta 5, 5 alpha, and 5 beta androstanes, pregnanes, and bile acids. Cholesterol-3 beta-sulfate was not desulfated by the alkylsteroidsulfatases nor were steroids or bile acids that were sulfated in positions other than the 3 position. The alkylsteroidsulfatases were induced by their substrates; bile acid sulfates, however, were poor inducers of the 3 beta-sulfatase and did not induce the 3 alpha-sulfatase activity. In intact bacterial cells, taurine and sulfite suppressed the induction of the alkylsteroidsulfatases and inhibited the activity of the arylsulfatase and alkylsteroidsulfatases. In cell homogenates, the arylsulfatase and alkylsteroidsulfatases activities were inhibited by sulfite and sulfate but not by taurine. Our results support the hypothesis that the main function of the steroidsulfatases in P. niger H4 is to provide the bacteria with sulfur for dissimilatory purposes.

Introduction: Oral bacteria must attach to hard and soft tissues to colonize the oral cavity in the presence of a variety of forces caused by shear and flow. In vitro models mimicking this dynamic process are indispensable to study factors that might interfere with the first step towards infection. For extrapolation purposes the comparability between the dynamics of colonization on hard vs. soft surfaces needs to be evaluated. Methods: The colonization of glass and epithelial cell surfaces by the periodontal pathogen Aggregatibacter actinomycetemcomitans was followed in time with two flow cell models: a modified Robbins device (MRD) and an in situ image analysis system. Results: The number of A. actinomycetemcomitans recovered from the soft surfaces in the MRD experiments was higher than on glass. The amount of bacteria on the hard surfaces kept increasing with time, while on soft surfaces saturation was reached. The microscope-mounted flow cell allowed real-time in situ monitoring of the colonization process of both surfaces. Conclusion: These experimental models may have a great contribution to make in the development of new treatment approaches for periodontal diseases. Colonization by A. actinomycetemcomitans could be studied under flow conditions and its dynamics showed important surface-dependent characteristics.

It is known that beneficial bacteria can suppress the emergence of pathogenic bacteria, particularly in the gastrointestinal tract. This study examined the potential for a similar suppression of Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans colonization of epithelial cells, due to its potential relevance in periodontal diseases. Seven presumed beneficial bacteria were examined for their ability to interfere, exclude, or displace A. actinomycetemcomitans from epithelial cells in vitro. Streptococcus sanguinis, Streptococcus mitis, and Streptococcus salivarius showed prominent inhibitory effects on either A. actinomycetemcomitans recovery or colonization. These results confirmed the hypothesis that bacterial interactions interfere with A. actinomycetemcomitans colonization of epithelial cells in vitro, and demonstrated the potential beneficial effects of S. mitis, S. salivarius, and S. sanguinis. ispartof: Journal of Dental Research vol:86 issue:7 pages:611-617 ispartof: location:United States status: published

Objectives: Epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) is poorly defined in cystic fibrosis (CF) patients, and S. aureus detection may be hampered by the presence of small colony variants (SCVs). We conducted a multicentre survey to determine the prevalence of S. aureus and MRSA colonization in Belgian CF patients and characterize the phenotype and clonal distribution of their staphylococcal strains. Methods: S. aureus isolated from CF patients attending nine CF centres were collected. Oxacillin resistance was detected by oxacillin agar screen and mecA PCR. Antibiotic susceptibility was tested by microdilution. MRSA strains were genotyped by PFGE and SCCmec typing and compared with hospital-associated MRSA strains. Results: Laboratories used a diversity of sputum culture procedures, many of which appeared substandard. S. aureus was isolated from 275/627 (44%) CF patients (20% to 72% by centre). The prevalence of SCV colonization was 4%, but SCVs were almost exclusively recovered from patients in two centres performing an SCV search. Phenotypically, 14% of S. aureus isolates were oxacillin-resistant: 79% carried mecA and 19% were SCVs lacking mecA. The mean prevalence of true MRSA colonization was 5% (0% to 17% by centre). By PFGE typing, 67% of CF-associated MRSA were related to five epidemic clones widespread in Belgian hospitals. Conclusions: This first survey of S. aureus colonization in the Belgian CF population indicated a diversity in local prevalence rates and in proportion of oxacillin-resistant and SCV phenotypes, probably related to variation in bacteriological methods. These findings underscore the need for standard S. aureus detection methods and MRSA control policies in Belgian CF centres.

Objectives The aim of this study was to examine the accuracy of the presence of high-risk human papillomavirus (HR-HPV) DNA (HR-HPV DNA test) postconisation as prediction of recurrent or residual cervical intraepithelial neoplasia (CIN) after treatment of high-grade cervical intraepithelial lesions (CIN2+) in a prospective study and to compare this with follow-up cytology and the marginal status of the excised tissue. Design Prospective follow-up study. Setting Unselected women presenting at colposcopy clinic of University Hospital Gasthuisberg, Leuven. Population Seventy-two women treated with conisation for CIN2 or CIN3. Methods Women were followed by HR-HPV DNA test (Hybrid Capture II test of Digene®) every 3 to 6 months. The same vial was used for cytology and the HR-HPV DNA test (SurePath™). All women were further followed by colposcopy and cytology for 24 months at 6-month intervals. The outcome of the study was presence of >CIN2, proven with colposcopy-directed biopsy occurring within 24 months after treatment. HR-HPV status was correlated with recurrent or residual CIN2+. Main outcome measures Sensitivity, specificity, predictive values and diagnostic odds ratios to predict treatment failure or cure were computed for HR-HPV testing, marginal status and follow-up cytology. HR-HPV status was also correlated with section margins postconisation and with the first cervical smear. Results In 6 of the 72 treated women (8%), residual or recurrent CIN occurred. Women with recurrence were significantly older than women without a recurrence (51.5 ± 9.6 versus 39.8 ± 12.2 years, P= 0.007). All six women with recurrence were HR-HPV positive, four had a positive follow-up smear (≥atypical squamous cells of uncertain significance = ASCUS+) and only two had involved section margins. Among the 66 cured women, 15 were HR-HPV positive, 6 had an abnormal smear and 12 had positive section margins. Sensitivity of cytology, positive section margins and HR-HPV DNA positivity was 66.7, 33.3 and 100% to predict treatment failure. Specificity of the three tests was, respectively, 90.9, 81.8 and 77.3%. Women with HR-HPV DNA at 3 to 6 months showed recurrent or residual CIN in 15% (2/13) if they had normal follow-up Pap smears and in 50% (4/8) if they had abnormal Pap smears. Margin status was not statistically significantly associated with human papillomavirus status. Conclusion Persistence or clearance of HR-HPV DNA is an early valid prognostic marker of failure or cure after treatment for CIN2+ and is more accurate than cytology or section margin status at the time of conisation. The absence of HR-HPV DNA has a 100% negative predictive value. Higher age at conisation may be a previously unrecognised risk factor for recurrence.

A total of 391 and 424 non-invasive isolates of Streptococcus pneumoniae collected by 15 laboratories during the 2003 and 2004 survey were tested for their susceptibility by a microdilution technique following NCCLS recommendations. Insusceptibility rates (IR) in the two surveys (2003/2004) were as follows: penicillin 15.0/14.7 % [8.4/6.4 % Resistance (R)], ampicillin 17.4/14.6 % (R 9.0/7.1 %), amoxicillin clavulanic acid 2.6/1.2 % (R 0/0 %),cefaclor 14.3/14.1 % (R 11.5/13.4%), cefuroxime 13.6/12.7 % (R 10.5/11.8 %), cefuroxime-axetil 10.5/11.8 % (R 10.0/9.2 %) (breakpointsbased on 250 mg), cefotaxime 4.9/6.2 % (R 1.3/2.4 %), ceftazidime NotTested (NT)/6.4 (R NT/2.6 %), cefepime NT/6.4 (R NT/2.6 %), imipenern 7.7/8.9 % (R 1.8/1.4 %), ertapenem 0.8/NT % (R 0/NT %), ciprofloxacin 13.8/9.0 % (R 4.3/2.4 %), levofloxacin 3.3/2.8 % (R 1.5/0.2 %), moxifloxacin 0.6/0.2 % (R 0.3/0 %), ofloxacin 13.5/9.0 % (R 4.3/2.4 %), erythromycin 26.1/24.7 % (R 25.3/24.5 %), azithromycin 25.4/24.7 % (R 24.6/24.5 %), telithromycin 0.8/0.2 % (R 0.5/0 %), clindamycin 21.2/18.4 % (R 19.2/17.7 %) and tetracycline 32.3/22.1 % (R 29.2/19.3 %). There were only minor differences in resistance rates according to age, sample site, admission type (i.e. ambulatory, hospitalized or long-term care facility patients), gender and geographic origin. Overall, telithromycin (MIC50, MIC90 in 2003/2004: 0.015 mu g/ml, 0.12 mu g/ml/ 0.008,0.06 respectively), ertapenem (0.03; 0.25/NT), moxifloxacin (0.06; 0.25/0.06,0.12), and amoxicillin +/- clavulanic acid (0.03; 0.25/0.015, 0.5) were the most active compounds in both surveys. In 2003, the most common resistance phenotype was isolated insusceptibility to tetracycline (10.5 %) followed by combined insusceptibility to erythromycin and tetracycline (9.3 %). Erythromycin-tetracycline resistance (10.4 %) was the most common in 2004. Isolates showing resistance to an antibiotic were significantly more present in 2003 than in 2004 (50.4 % versus 40.8 %). In penicillin-insusceptible isolates, MICs of all beta-lactams were increased but cross-resistance between penicillin and other beta-lactams in the penicillin-insusceptible isolates was not complete. In the 2003 survey, most of these isolates remained fully susceptible to ertapenem (94.9 %) and amoxicillin +/- clavulanic acid (83.1 %). In the 2004 survey, 91.9 % of the penicillin insusceptibie isolates remained susceptible to amoxicillin clavulanic acid. In both surveys, the most common serotypes in penicillin insusceptible isolates were 14, 23, 19 and 9 (20.0 %, 20.0 %, 16.4 % and 10.9 % respectively in 2003; 41.6 %, 11.7 %, 15.0 % and 18.3 % respectively in 2004).

Intra-abdominal infection is a common cause of severe sepsis in a hospital setting and remains associated with a significant morbidity, mortality and resource use. Early adequate surgery or drainage remain the cornerstones of intra-abdominal infection management and impact on patients outcome. Concomitant early and adequate empiric antimicrobial therapy further influences patients morbidity and mortality. Multiple empirical regimens have been proposed in this setting, but rarely supported by well designed, randomized-controlled studies. The current manuscript summarizes the recommendations of the Infection Disease Advisory Board on the management of intra-abdominal infections. Empiric antimicrobial therapy for the most common causes of abdominal infections is proposed. In addition, particular attention has been paid on antibiotic treatment duration.

Coagulase-negative staphylococcus (CNS) is the most frequent cause of nosocomial bacteremia and prosthetic valve endocarditis. CNS bacteremia can be polyclonal. No data exist on the clonality of CNS causing endocarditis. We present a case of CNS aortic homograft endocarditis in which at least five different genotypes of CNS were identified in initial blood-culture isolates by genomic macrorestriction enzyme analysis and pulsed field gel electrophoresis. Since the polyclonality was accompanied by differences in antibiotic susceptibility, this observation may have important consequences for the treatment of CNS endocarditis. Because of the parallels in the pathogenesis of CNS prosthetic valve endocarditis and CNS infections of a variety of other prosthetic devices, it might also have consequences for CNS prosthetic device infections in general. We suggest that antibiotic susceptibility testing of just one blood-culture isolate may be insufficient.

We describe the development and application of a rapid and universal molecular technique for direct identification of multiple bacteria in clinical samples. Amplification of the 16S-23S rRNA spacer-region using universal primers led to fragment patterns distinct for different bacterial species and that were analyzed with fluorescent amplicon length analysis (FALA). 136 pure cultures of clinical isolates and 20 culture collection strains belonging to 22 different medically important species were used to create a primary database of fragments with sizes between 100 and 1000 bp. Subsequently, 127 respiratory samples were analyzed with culture-based techniques and via FALA of the 16S-23S rRNA spacer-region. Two DNA extraction methods were evaluated: Instagene (FALA-I) and Fastprept (FALA-P). Of the 127 samples, 26 culture-negative samples were also negative with FALA-P. Of 18 samples with growth of commensal oral flora, 10 gave a mixed oral flora pattern with FALA-P and 8 gave a negative result. For 54 samples with growth of a single bacterial species, FALA-P gave an identical result for 46. For 29 samples with growth of more than one bacterial species, identical results were obtained in 19 samples. False-negative results with FALA-P were mostly due to paucity (less than 10(3) CFU/ml) of bacteria (12 out of 18 false-negatives) or difficulties with homogenization of viscous samples (6 out of 18 false-negatives).With regard to identification of all significant pathogens of clinical samples tested, the sensitivity of FALA-P was 77% and its specificity was 100%. With FALA-I, the number of false-negative results was higher than with FALA-P due to less efficient extraction of DNA, particularly with Staphylococcal species. FALA-P allows rapid and direct identification of multiple species directly from clinical samples; pauci-cellular samples may give false-negative results.

We report a case of cryptococcal meningitis in an immunocompetent female patient with exposure to a pet magpie (Pica pica). Genetically indistinguishable isolates were cultured from the cerebrospinal fluid of the patient and excreta of the bird. Our data strongly suggest zoonotic transmission of Cryptococcus neoformans var. grubii from a magpie to this patient.

Quinolones are one of the largest classes of antimicrobial agents used worldwide. This review considers the quinolones that are available currently and used widely in Europe (norfoxacin, ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin) within their historical perspective, while trying to position them in the context of recent and possible future advances based on an understanding of: (1) their chemical structures and how these impact on activity and toxicity; (2) resistance mechanisms (mutations in target genes, efflux pumps); (3) their pharmacodynamic properties (AUC/MIC and Cmax /MIC ratios; mutant prevention concentration and mutant selection window); and (4) epidemiological considerations (risk of emergence of resistance, clonal spread). Their main indications are examined in relation to their advantages and drawbacks. Overall, it is concluded that these important agents should be used in an educated fashion, based on a careful balance between their ease of use and efficacy vs. the risk of emerging resistance and toxicity. However, there is now substantial evidence to support use of the most potent drug at the appropriate dose whenever this is required.

The aim of this project was to study the influence of pneumococci on nasopharyngeal epithelial integrity as a function of time and pneumococcal density.Cell layers of an in vitro model of human nasopharyngeal epithelium were inoculated with different pneumococcal strains. The transepithelial electrical resistance (TEER), a measure of the integrity of the cell layers, and the pneumococcal concentration in the apical fluid on the epithelial cells were measured at different times after inoculation.Pneumococci caused a decrease in the TEER when a density of 1 x 107 CFU mL-1 was reached. The growth rate of pneumococci in our in vitro model differed between the strains tested and, for the same strain, between in vitro culture on the epithelial cells and broth culture. Differences in timing of the onset of decrease in the TEER between strains were the result of differences in growth rate on the epithelial cells. Antibiotic-induced lysis of pneumococci caused an immediate decrease in the TEER of the cell layers.Pneumococci cause a decrease in the TEER at a density of 1 x 107 CFU mL-1. Our hypothesis is that this decrease in the TEER is the result of quorum-induced lysis of the pneumococci.

Objectives: To determine susceptibility rates and patterns in Pseudomonas aeruginosa strains isolated from nosocomial infections. Methods: Seven hundred and sixteen P. aeruginosa isolates from 40 different hospitals in Belgium and the Grand Duchy of Luxembourg were collected in 1999. Results: Resistance rates varied significantly between hospitals. Of the fluoroquinolones, ciprofloxacin showed least resistance (24%), levofloxacin showed 27.5% resistance and ofloxacin 37.5%. Of the aminoglycosides, amikacin was the most potent antibiotic (10.5% resistance), followed by isepamicin (12%), tobramycin (19.5%) and gentamicin (23.5%). Of the β-lactam antibiotics, meropenem was the most active (9.5% resistance); piperacillin and piperacillin/tazobactam had, respectively, 24% and 17.5% resistance, ceftazidime 28.5%, cefepime 29.5%, ticarcillin/clavulanic acid 37% and aztreonam 55.5%. MIC distribution curves show the presence of significant subpopulations, with MICs just below breakpoint for many antibiotics. Conclusion: Resistance of P. aeruginosa to penicillins, cephalosporins, fluoroquinolones and aminoglycosides varies between hospitals, but is increasing.

An internal RNA standard proved less suitable in bacterial gene expression experiments. We therefore developed a method for simultaneous RNA and gDNA (genomic DNA) isolation from in vitro and in vivo samples containing staphylococci and combined it with quantitative PCR. The reliability of gDNA for bacterial quantification and for standardisation in gene expression experiments was evaluated. Quantitative PCR proves equivalent to quantitative culture for in vitro samples, and superior for in vivo samples. In gene expression experiments, gDNA permits a good standardisation for the initial amount of bacteria. The average interassay variability of the in vitro expression is 20.1%. The in vivo intersample variability was 73.3%. This higher variability can be attributed to the biological variation of gene expression in vivo. This method permits exact quantification of the number of bacteria and the expression of genes in staphylococci in vivo (e.g., in biofilms, evolution in time) and in vitro.

Community acquired bacterial meningitis remains a feared infection because of its high morbidity and mortality. During the last decade, the incidence and the microbial resistance patterns of pathogens causing bacterial meningitis have changed considerably. A sharp increase in meningococcal disease has been observed and meningitis caused by penicillin resistant Streptococcus pneumoniae emerged as a matter of major concern. Since pneumococcal resistance in Belgium to third generation cephalosporins remains rare and low level, addition of vancomycin to the initial empirical therapy including third generation cephalosporins is not yet necessary. However, the evolution of the resistance patterns of invasive S. pneumoniae should be followed very carefully. The emergence of penicillin resistant pneumococci also raises concern about the safety of adjuvant anti-inflammatory therapy with dexamethasone. Although there is a growing evidence suggesting a decrease of neurological complications after administration of adjuvant dexamethasone, this therapy may lower the already borderline penetration through the blood-brain barrier of the currently used antibiotics. This may result in therapeutic failure. We therefore presently do not advocate the routine use of dexamethasone in the therapy of adult bacterial meningitis.

The mucosae of the oro-nasopharynx in man are asymptomatically colonised by a commensal flora. This commensal flora consists largely of non-pathogenic bacteria but potentially pathogenic bacteria, such as S. pneumoniae, H. influenzae, M. catarrhalis can also be part of it. The commensal flora can be affected by host factors such as age or antibiotic usage but will in itself also affect its host. In addition to being a source of resistance genes it will also protect the host against exogenous, non-commensal pathogens. This protective effect is the result of three characteristics of the commensal flora. The commensal flora will hinder the establishment of new pathogens on the mucosa (termed colonisation resistance), it will especifically stimulate the immune system and it will induce formation of protective antibodies.

We have investigated the influence of subinhibitory concentrations of erythromycin on the interaction between Streptococcus pneumoniae and human respiratory epithelial cells. Confluent in vitro cell cultures were inoculated with erythromycin-resistant S. pneumoniae and incubated for 24 h. Erythromycin significantly reduced adherence of the pneumococci after 4 h and 24 h: 4.0% +/- 0.7% (mean +/- S.E.M. ) of the pneumococci adhered to the epithelial cells in medium with erythromycin, compared with 7.7% +/- 0.8% in medium without erythromycin (P: = 0.002) after 4 h, and the corresponding values after 24 h were 24.2% +/- 5.3% and 38.4% +/- 5.0%, respectively (P: = 0.038). Disruption of epithelial integrity by S. pneumoniae, measured as the decrease in transepithelial electrical resistance, was delayed in the presence of erythromycin. Neither addition of erythromycin to the culture medium nor infection of the cell cultures with pneumococci significantly affected secretion of interleukin-8 by the epithelial cells. Addition of erythromycin to a pneumococcal suspension in cell culture medium without respiratory epithelial cells almost completely prevented the release of pneumolysin. We conclude that erythromycin at subinhibitory concentrations reduces the adherence to and disruption of respiratory epithelial cells by S. pneumoniae, possibly by interfering with pneumolysin release.