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The aim of this study was to determine whether bacterial adhesion and biofilm formation occur on various ureteric stent materials in vivo and in vitro and whether there is any correlation between biofilm formation and urinary tract infection. Using an open surgical procedure, 23 double-J stents of 8 different types were inserted in the ureters of 13 piglets. After 6 weeks intubation, 2 (9%) of the 23 stented renal units yielded positive urine culture. Scanning Electron Microscopy (SEM) showed sporadic bacteria on 7 (30%) of the 23 indwelling ureteric stents and bacterial biofilms on only 2 (9%), those indwelling the renal units which yielded positive urine cultures. Precut segments of the 8 double-J stent brands were incubated with 5 different bacterial strains. Microbiological and SEM analysis of the stents revealed that only 0.1-0.01% of the bacterial inoculum adhered to the stents. There was no statistically significant difference in bacterial adherence to the various stent materials. Interestingly, the two Escherichia coli strains with P-fimbriae adhered significantly more than the two without P-fimbriae. Sporadic bacterial adhesion to ureteric stents seemed to have little clinical significance whereas biofilm formation seemed to result in urinary tract infection. None of the tested stents proved to be superior to the others in this respect, and adhesion appeared to depend on the virulence of the bacteria rather than the properties of the biomaterials.

In an attempt to compare the epidemiology of severe Streptococcus pyogenes infection within Europe, prospective data were collected through the Strep-EURO program. Surveillance for severe cases of S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in 11 countries across Europe by using a standardized case definition and questionnaire. Patient data as well as bacterial isolates were collected and characterized by T and M/emm typing, and selected strains were analyzed for the presence of superantigen genes. Data were analyzed to compare the clinical and microbiological patterns of the infections across the participating countries. A total of 4,353 isolates were collected from 5,521 cases with severe S. pyogenes infections who were identified. A wide diversity of M/emm types (n = 104) was found among the S. pyogenes clinical isolates, but the M/emm type distribution varied broadly between participating countries. The 10 most predominant M/emm types were M/emm type 1 (M/emm1), M/emm28, M/emm3, M/emm89, M/emm87, M/emm12, M/emm4, M/emm83, M/emm81, and M/emm5, in descending order. A correlation was found between some specific disease manifestations, the age of the patients, and the emm types. Although streptococcal toxic shock syndrome and necrotizing fasciitis were caused by a large number of types, they were particularly associated with M/emm1 and M/emm3. The emm types included in the 26-valent vaccine under development were generally well represented in the present material; 16 of the vaccine types accounted for 69% of isolates. The Strep-EURO collaborative program has contributed to enhancement of the knowledge of the spread of invasive disease caused by S. pyogenes within Europe and encourages future surveillance by the notification of cases and the characterization of strains, which are important for vaccination strategies and other health care issues. Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Nowadays, six types of acquired vancomycin resistance in enterococci are known; however, only VanA and to a lesser extent VanB are widely prevalent. Various genes encode acquired vancomycin resistance and these are typically associated with mobile genetic elements which allow resistance to spread clonally and laterally. The major reservoir of acquired vancomycin resistance is Enterococcus faecium; vancomycin-resistant Enterococcus faecalis are still rare. Population analysis of E. faecium has revealed a distinct subpopulation of hospital-acquired strain types, which can be differentiated by molecular typing methods (MLVA, MLST) from human commensal and animal strains. Hospital-acquired E. faecium have additional genomic content (accessory genome) including several factors known or supposed to be virulence-associated. Acquired ampicillin resistance is a major phenotypic marker of hospital-acquired E. faecium in Europe and experience has shown that it often precedes increasing rates of VRE with a delay of several years. Several factors are known to promote VRE colonisation and transmission; however, despite having populations with similar predispositions and preconditions, rates of VRE vary all over Europe.

The past 2 decades have brought worrying increases in severe Streptococcus pyogenes diseases globally. To investigate and compare the epidemiological patterns of these diseases within Europe, data were collected through a European Union FP-5-funded program (Strep-EURO). Prospective population-based surveillance of severe S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in 11 countries across Europe (Cyprus, the Czech Republic, Denmark, Finland, France, Germany, Greece, Italy, Romania, Sweden, and the United Kingdom) using a standardized case definition. A total of 5,522 cases were identified across the 11 countries during this period. Rates of reported infection varied, reaching 3/100,000 population in the northern European countries. Seasonal patterns of infection showed remarkable congruence between countries. The risk of infection was highest among the elderly, and rates were higher in males than in females in most countries. Skin lesions/wounds were the most common predisposing factor, reported in 25% of cases; 21% had no predisposing factors reported. Skin and soft tissue were the most common foci of infection, with 32% of patients having cellulitis and 8% necrotizing fasciitis. The overall 7-day case fatality rate was 19%; it was 44% among patients who developed streptococcal toxic shock syndrome. The findings from Strep-EURO confirm a high incidence of severe S. pyogenes disease in Europe. Furthermore, these results have identified targets for public health intervention, as well as raising awareness of severe S. pyogenes disease across Europe. Copyright © 2008, American Society for Microbiology. All Rights Reserved.

We analyzed a representative sample of methicillin-resistant Staphylococcus aureus (MRSA) from 11 European countries (referred to as the HARMONY collection) using three molecular typing methods used within the HARMONY group to examine their usefulness for large, multicenter MRSA surveillance networks that use these different laboratory methodologies. MRSA isolates were collected based on their prevalence in each center and their genetic diversity, assessed by pulsed-field gel electrophoresis (PFGE). PFGE groupings (≤3 bands difference between patterns) were compared to those made by sequencing of the variable repeats in the protein A gene spa and clonal designations based on multilocus sequence typing (MLST), combined with PCR analysis of the staphylococcal chromosome cassette containing the mec genes involved in methicillin resistance (SCCmec). A high level of discrimination was achieved using each of the three methodologies, with discriminatory indices between 89.5% and 91.9% with overlapping 95% confidence intervals. There was also a high level of concordance of groupings made using each method. MLST/SCCmec typing distinguished 10 groups containing at least two isolates, and these correspond to the majority of nosocomial MRSA clones described in the literature. PFGE and spa typing resolved 34 and 31 subtypes, respectively, within these 10 MRSA clones, with each subtype differing only slightly from the most common pattern using each method. The HARMONY group has found that the methods used in this study differ in their availability and affordability to European centers involved in MRSA surveillance. Here, we demonstrate that the integration of such technologies is achievable, although common protocols (such as we have developed for PFGE) may also be important, as is the use of centralized Internet sites to facilitate data analysis. PFGE and spa-typing data from analysis of MRSA isolates from the many centers that have access to the relevant equipment can be compared to reference patterns/sequences, and clonal designations can be made. In the majority of cases, these will correspond to those made by the (more expensive) method of choice - MLST/SCCmec typing - and these alternative methods can therefore be used as frontline typing systems for multicenter surveillance of MRSA. Copyright © 2007, American Society for Microbiology. All Rights Reserved.

http://www.srga.org/SSAC/doc/2005/SSAC_MRSAreport_2004.pdf

Pulsed-field gel electrophoresis (PFGE) is the most common genotypic method used in reference and clinical laboratories for typing methicillin-resistant Staphylococcus aureus (MRSA). Many different protocols have been developed in laboratories that have extensive experience with the technique and have established national databases. However, the comparabilities of the different European PFGE protocols for MRSA and of the various national MRSA clones themselves had not been addressed until now. This multinational European Union (EU) project has established for the first time a European database of representative epidemic MRSA (EMRSA) strains and has compared them by using a new “harmonized” PFGE protocol developed by a consensus approach that has demonstrated sufficient reproducibility to allow the successful comparison of pulsed-field gels between laboratories and the tracking of strains around the EU. In-house protocols from 10 laboratories in eight European countries were compared by each center with a “gold standard” or initial harmonized protocol in which many of the parameters had been standardized. The group found that it was not important to standardize some elements of the protocol, such as the type of agarose, DNA block preparation, and plug digestion. Other elements were shown to be critical, namely, a standard gel volume and concentration of agarose, the DNA concentration in the plug, the ionic strength and volume of running buffer used, the running temperature, the voltage, and the switching times of electrophoresis. A new harmonized protocol was agreed on, further modified in a pilot study in two laboratories, and finally tested by all others. Seven laboratories’ gels were found to be of sufficiently good quality to allow comparison of the strains by using a computer software program, while two gels could not be analyzed because of inadequate destaining and DNA overloading. Good-quality gels and inclusion of an internal quality control strain are essential before attempting intercenter PFGE comparisons. A number of clonally related strains have been shown to be present in multiple countries throughout Europe. The well-known Iberian clone has been demonstrated in Belgium, Finland, France, Germany, and Spain (and from the wider HARMONY collection in Portugal, Slovenia, and Sweden). Strains from the United Kingdom (EMRSA-15 and -16) have been identified in several other countries, and other clonally related strains have also been identified. This highlights the need for closer international collaboration to monitor the spread of current epidemic strains as well as the emergence of new ones.

Twenty well characterized isolates of methicillin-resistant Staphylococcus aureus were used to study the optimal resolution and interlaboratory reproducibility of pulsed-field gel electrophoresis (PFGE) of DNA macrorestriction fragments. Five identical isolates tone PFGE type), 5 isolates that produced related PFGE subtypes, and 10 isolates with unique PFGE patterns were analyzed blindly in 12 different laboratories by inhouse protocols. In several laboratories a standardized PFGE protocol with a commercial kit was applied successfully as well. Eight of the centers correctly identified the genetic homogeneity of the identical isolates by both the in-house and standard protocols. Four of 12 laboratories failed to produce interpretable data by the standardized protocol, due to technical problems (primarily plug preparation). With the five related isolates, five of eight participants identified the same subtype interrelationships with both in-house and standard protocols. However, two participants identified multiple strain types in this group or classified some of the isolates as unrelated isolates rather than as subtypes. The remaining laboratory failed to distinguish differences between some of the related isolates by utilizing both the in-house and standardized protocols. There were large differences in the relative genome lengths of the isolates as calculated on the basis of the gel pictures. By visual inspection, the numbers of restriction fragments and overall banding pattern similarity in the three groups of isolates showed interlaboratory concordance, but centralized computer analysis of data from four laboratories yielded percent similarity values of only 85% for the group of identical isolates. The differences between the data sets obtained with in-house and standardized protocols could be the experimental parameters which differed with respect to the brand of equipment used, imaging software, running time (20 to 48 h), and pulsing conditions. In conclusion, it appears that the standardization of PFGE depends on controlling a variety of experimental intricacies, as is the case with other bacterial typing procedures.

Background: T-tube-related bacteriobilia causes infectious complications and obstruction. To prevent these, the choice of T-tube material may be of importance. Methods: Transected common bile ducts (CBDs) of 17 piglets were sutured over latex or silicone T-tubes, or without a T-tube. Results: After 6 weeks bacteriobilia was found in all of 12 CBDs with and in 1 of 5 CBDs without a T-tube (p < 0.05). By scanning electron microscopy (SEM) four of five latex and none of five silicone T-tubes had bacterial biofilms (p < 0.05). All tubes remained patent. Segments of T-tubes were incubated with five different bacterial strains. Sonication and SEM showed that 0.1–1.1% of 107 colony-forming units of inoculum adhered to T-tubes. Two to six times more bacteria adhered to latex than to silicone (p < 0.05). Conclusions: Silicone offers better long-term patency than latex. Less infectious complications occur if T-tubes are omitted.