Search

Objectives Osteoarthritis has been the subject of abundant research in the last years with limited translation to the clinical practice, probably due to the disease's high heterogeneity. In this study, we aimed to identify different phenotypes in knee osteoarthritis (KOA) patients with joint effusion based on their metabolic and inflammatory profiles. Methods A non-supervised strategy based on statistical and machine learning methods was applied to 45 parameters measured on 168 female KOA patients with persistent joint effusion, consecutively recruited at our hospital after a monographic OA outpatient visit. Data comprised anthropometric and metabolic factors and a panel of systemic and local inflammatory markers. The resulting clusters were compared regarding their clinical, radiographic and ultrasound severity at baseline and their radiographic progression at two years. Results Our analyses identified four KOA inflammatory phenotypes (KOIP): a group characterized by metabolic syndrome, probably driven by body fat and obesity, and by high local and systemic inflammation (KOIP-1); a metabolically healthy phenotype with mild overall inflammation (KOIP-2); a non-metabolic phenotype with high inflammation levels (KOIP-3); and a metabolic phenotype with low inflammation and cardiovascular risk factors not associated with obesity (KOIP-4). Of interest, these groups exhibited differences regarding pain, functional disability and radiographic progression, pointing to a clinical relevance of the uncovered phenotypes. Conclusion Our results support the existence of different KOA phenotypes with clinical relevance and differing pathways regarding their pathophysiology and disease evolution, which entails implications in patients' stratification, treatment tailoring and the search of novel and personalized therapies. [ABSTRACT FROM AUTHOR]

Background: Limited information is available on pneumococcal colonization among adults. We studied pneumococcal carriage dynamics in healthy adults using high-sensitivity approaches.Methods: Eighty-seven adults (25-50 years old) were followed for 6 months in Portugal. Nasopharyngeal, oropharyngeal, and saliva samples were obtained monthly; pneumococcal carriers were also sampled weekly. Carriage was investigated by quantitative polymerase chain reaction (targeting lytA and piaB) and culture. Positive samples were serotyped.Results: Approximately 20% of the adults were intermittent carriers; 10% were persistent carriers (>4 months). Pneumococcal acquisition and clearance rates were 16.5 (95% confidence interval [CI], 11.2-24.2) and 95.9 (95% CI, 62.3-145.0) cases/1000 person-weeks, respectively. Living with children increased pneumococcal acquisition (hazard ratio, 9.7 [95% CI, 2.6-20.5]; P < .001). Median duration of carriage was 7 weeks and did not depend on regular contact with children.Conclusions: The pneumococcal carrier state in healthy adults is more dynamic than generally assumed: Acquisition is frequent and duration of carriage is often long. This suggests that some adults may act as reservoirs of pneumococci and hence, depending on the social structure of a community, the magnitude of herd effects potentially attainable through children vaccination may vary. These findings are important when designing strategies to prevent pneumococcal disease in adults. [ABSTRACT FROM AUTHOR]

Objectives: We present the results of two European external quality assessments (EQAs) conducted in 2014 and 2016 under the auspices of the Study Group on Staphylococci and Staphylococcal Infections of ESCMID. The objective was to assess the performance of participating centres in characterizing Staphylococcus aureus using their standard in-house phenotypic and genotypic protocols.Methods: A total of 11 well-characterized blindly coded S. aureus (n = 9), Staphylococcus argenteus (n = 1) and Staphylococcus capitis (n = 1) strains were distributed to participants for analysis. Species identification, MIC determination, antimicrobial susceptibility testing, antimicrobial resistance and toxin gene detection and molecular typing including spa typing, SCCmec typing and MLST were performed.Results: Thirteen laboratories from 12 European countries participated in one EQA or both EQAs. Despite considerable diversity in the methods employed, good concordance (90%-100%) with expected results was obtained. Discrepancies were observed for: (i) identification of the S. argenteus strain; (ii) phenotypic detection of low-level resistance to oxacillin in the mecC-positive strain; (iii) phenotypic detection of the inducible MLSB strain; and (iv) WGS-based detection of some resistance and toxin genes.Conclusions: Overall, good concordance (90%-100%) with expected results was observed. In some instances, the accurate detection of resistance and toxin genes from WGS data proved problematic, highlighting the need for validated and internationally agreed-on bioinformatics pipelines before such techniques are implemented routinely by microbiology laboratories. We strongly recommend all national reference laboratories and laboratories acting as referral centres to participate in such EQA initiatives. [ABSTRACT FROM AUTHOR]

The article discusses the bacterial activities of octenidine as the antibiotic resistance to the epidemic clones of Methicillin-resistant Staphylococcus Aureus (MRSA) strains which also includes antimicrobials such as mupirocin. It shows that polyhexanide gives promising results but octenidine is more successful in decontaminating MRSA.

Objectives: Recent surveillance of MRSA colonizing patients and healthcare workers in two African countries (Angola and São Tomé and Príncipe) reported the frequent recovery of oxacillin-susceptible MRSA (OS-MRSA): Staphylococcus aureus strains that gave positive results with the mecA DNA probe, but had low oxacillin MIC values characteristic of susceptible S. aureus. This apparent dissociation of the drug-resistant phenotype from mecA-the primary genetic determinant of resistance-prompted us to perform a more detailed analysis on nine of the African OS-MRSA strains.Methods: Oxacillin MIC values were determined by Etest and population analysis profiles with and without induction of the stringent stress response by mupirocin. Biochemical profiling using SDS-PAGE followed by western blotting was used for the detection of PBP2A protein produced.Results: Cultures of the African MRSA strains (ST88-IVa and ST8-V) showed heterogeneous oxacillin resistance in which the majority of cells exhibited low oxacillin MICs (≤0.75 mg/L), but highly resistant subpopulations were also present with oxacillin MIC values up to several hundred mg/L and with frequencies of 10(-4) to 10(-6). The same strains after induction of the stringent stress response by mupirocin 'converted' the heterogeneous phenotypes into a more homogeneous and higher level resistance. After induction by oxacillin and mupirocin, each of the nine African OS-MRSA strains produced PBP2A-the protein product of mecA.Conclusions: The resistant phenotype of OS-MRSA resembles the phenotypes of historically early MRSA clones. The nature of genetic determinants responsible for the heterogeneous phenotypes of OS-MRSA remains to be determined. [ABSTRACT FROM AUTHOR]

Background: Oxacillin-susceptible mecA-positive Staphylococcus aureus (OS-MRSA) isolates have been increasingly reported worldwide, but data regarding the African continent have not been available.Methods: Between 2010 and 2014, 1462 inpatients and healthcare workers were screened for MRSA nasal carriage in São Tomé and Príncipe (STP) and Angola, two Portuguese-speaking African countries (PALOP countries). We determined the presence of the mecA gene and the antimicrobial susceptibility profiles of the isolates. OS-MRSA clonal lineages were identified as well as the presence of virulence determinants, including Panton-Valentine leucocidin (PVL).Results: Out of 164 S. aureus hospital isolates tested, 29 (17.7%) were mecA positive, but susceptible to oxacillin, showing oxacillin MICs ≤3 mg/L. All OS-MRSA isolates were resistant to cefoxitin and most of them were also resistant to at least two antimicrobials other than β-lactams. The 29 OS-MRSA were distributed into two major clonal lineages: (i) PFGE type B-ST88-SCCmec IVa, associated with spa types t186/t325/t786/t1814/t1951, detected in Angola (n = 5) and STP (n = 10); and (ii) PFGE type C-t451/t648-ST8-SCCmec V, exclusively found in STP (n = 9). OS-MRSA showed at least two virulence determinants. PVL was detected in an isolate recovered in STP.Conclusions: We describe a high prevalence of OS-MRSA among S. aureus strains recovered in two African countries. OS-MRSA in PALOP countries were mainly associated with ST88 and ST8, two prevalent MRSA clonal types in these countries. If direct testing for mecA is not available, cefoxitin susceptibility testing is highly recommended to avoid the misidentification of OS-MRSA. [ABSTRACT FROM AUTHOR]

The opportunistic pathogens Staphylococcus aureus and Staphylococcus epidermidis represent major causes of severe nosocomial infection, and are associated with high levels of mortality andmorbidity worldwide. These species are both commoncommensals on the human skin and in the nasal pharynx, but are genetically distinct, differing at 24% average nucleotide divergence in 1,478 core genes. To better understand the genome dynamics of these ecologically similar staphylococcal species, we carried out a comparative analysis of 324 S. aureus and S. epidermidis genomes, including 83 novel S. epidermidis sequences. A reference pan-genome approach andwhole genomemultilocus-sequence typing revealed that around half of the genomewas shared between the species. Based on a BratNextGen analysis, homologous recombination was found to have impacted on 40% of the core genes in S. epidermidis, but on only 24% of the core genes in S. aureus. Homologous recombination between the species is rare, with a maximum of nine gene alleles shared between any two S. epidermidis and S. aureus isolates. In contrast, there was considerable interspecies admixture of mobile elements, in particular genes associated with the SaPIn1 pathogenicity island, metal detoxification, and the methicillin-resistance island SCCmec. Our data and analysis provide a context for considering the nature of recombinational boundaries between S. aureus and S. epidermidis and, the selective forces that influence realized recombination between these species. [ABSTRACT FROM AUTHOR]

The surrounding capsule of Streptococcus pneumoniae has been identified as a major virulence factor and is targeted by pneumococcal conjugate vaccines (PCV). However, nonencapsulated S. pneumoniae (non-Ec-Sp) have also been isolated globally, mainly in carriage studies. It is unknown if non-Ec-Sp evolve sporadically, if they have high antibiotic nonsusceptiblity rates and a unique, specific gene content. Here, whole-genome sequencing of 131 non-Ec-Sp isolates sourced from 17 different locations around the worldwas performed. Results revealed a deep-branching classic lineage that is distinct frommultiple sporadic lineages. The sporadic lineages clustered with a previously sequenced, global collection of encapsulated S. pneumoniae (Ec-Sp) isolates while the classic lineage is comprised mainly of the frequently identified multilocus sequences types (STs) ST344 (n=39) and ST448 (n=40).All ST344 and nine ST448 isolates had high nonsusceptiblity rates to β-lactams and other antimicrobials. Analysis of the accessory genome reveals that the classic non-Ec-Sp contained an increased number of mobile elements, than Ec-Sp and sporadic non-Ec-Sp. Performing adherence assays to human epithelial cells for selected classic and sporadic non-Ec-Sp revealed that the presence of a integrative conjugative element (ICE) results in increased adherence to humanepithelial cells (P= 0.005). Incontrast, sporadic non-Ec- Sp lacking the ICE had greater growth in vitro possibly resulting in improved fitness. In conclusion, non-Ec-Sp isolates from the classic lineage have evolved separately. They have spread globally, are well adapted to nasopharyngeal carriage and are able to coexist with Ec-Sp. Due to continued use of PCV, non-Ec-Sp may become more prevalent. [ABSTRACT FROM AUTHOR]

All clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates examined so far contain the mecA gene, a 2130bp stretch of DNA of non-staphylococcal origin which, together with a larger block (up to 40-60 Kb) of 'foreign' DNA, is incorporated into the staphylococcal chromosome. mecA encodes for the 78 Kd penicillin-binding protein (PBP) 2A, which has very low affinity for beta-lactam antibiotics. The sequence of the mecA gene contains structural motifs characteristic of cell wall synthetic transpeptidases. It is generally assumed that the mecA gene product (PBP 2A) acts as a surrogate enzyme which takes over the task of cell wall synthesis from the normal complement of staphylococcal PBPs, since the latter are inhibited by relatively low (e.g. methicillin) concentrations of beta-lactam antibiotics. While direct biochemical evidence for a transpeptidase activity in PBP 2A is still missing, the essentiality of an intact mecA gene for the expression of high-level methicillin resistance has been clearly established by transposon inactivation experiments. On the other hand, it was already noted some time ago that an intact mecA and its gene product PBP 2A alone cannot be fully in control of the resistant phenotype, since all MRSA isolates, irrespective of their MIC values (from as low as 3 mg/L or as high as 1600 mg/L), were found to contain comparable amounts of PBP 2A. Such major disparities between cellular amounts of PBP 2A and the antibiotic MIC values suggested that a factor or factors of unknown nature ('factor X') other than the mecA gene product also played an essential role in the phenotypic expression of resistance. The same conclusion was reached in early genetic studies in which methicillin resistance could be reduced by insertional inactivation of a chromosomal site (omega 2003) within the so-called femA gene--(factor essential for the expression of methicillin resistance) outside the mecA determinant. More recently, several additional chromosomal sites were identified outside the mecA gene in which transposon inactivation reduced the level of beta-lactam resistance. The importance of these genes becomes clear if one realizes that it is the appropriate functioning of these determinants (in the genetic background of MRSA) rather than the quantity of PBP 2A in the cells that seems to determine the MIC value of an MRSA isolate. It is not clear at the present time how many such 'auxiliary genes' exist and exactly how these gene co-operate with the mecA gene in bringing about high-level beta-lactam resistance.(ABSTRACT TRUNCATED AT 400 WORDS) [ABSTRACT FROM AUTHOR]

Consecutive single-patient methicillin-resistant Staphylococcus aureus (MRSA) isolates (270) from 12 hospitals (8217 beds) in metropolitan New York City were collected during May 1996. In 11 of 12 hospitals, MRSA was most frequent in the general medical services. DNA typing ("fingerprinting") revealed that mecA:Tn554:PFGE (pulsed-field gel electrophoresis) type I:A:A accounted for 113 (42%) of 270 isolates, was detected in all hospitals, and was the predominant clone in 9. Thirteen of 15 I:E:F isolates were from 1 hospital, and the remaining 2 were from another hospital of the same health system. Type V:NH:E was isolated from 22 (79%) of the 28 patients with AIDS, including 8 of 9 patients from an additional hospital. Subtype V:NH:E2 was recovered from 11 patients, 9 of whom had AIDS, including all 5 AIDS patients from one floor of a nursing home affiliated with a third hospital. By using both mecA:Tn554 probes and PFGE, MRSA clusters and outbreaks may be detected and provide a rationale for appropriate infection control intervention. [ABSTRACT FROM AUTHOR]

The multidrug-resistant Streptococcus pneumoniae Taiwan19F-14, or PMEN14, clone was first observed with a 19F serotype, which is targeted by the heptavalent polysaccharide conjugate vaccine (PCV7). However, “vaccine escape” PMEN14 isolates with a 19A serotype became an increasingly important cause of disease post-PCV7. Whole genome sequencing was used to characterize the recent evolution of 173 pneumococci of, or related to, PMEN14. This suggested that PMEN14 is a single lineage that originated in the late 1980s in parallel with the acquisition of multiple resistances by close relatives. One of the four detected serotype switches to 19A generated representatives of the sequence type (ST) 320 isolates that have been highly successful post-PCV7. A second produced an ST236 19A genotype with reduced resistance to β-lactams owing to alteration of pbp1a and pbp2x sequences through the same recombination that caused the change in serotype. A third, which generated a mosaic capsule biosynthesis locus, resulted in serotype 19A ST271 isolates. The rapid diversification through homologous recombination seen in the global collection was similarly observed in the absence of vaccination in a set of isolates from the Maela refugee camp in Thailand, a collection that also allowed variation to be observed within carriage through longitudinal sampling. This suggests that some pneumococcal genotypes generate a pool of standing variation that is sufficiently extensive to result in “soft” selective sweeps: The emergence of multiple mutants in parallel upon a change in selection pressure, such as vaccine introduction. The subsequent competition between these mutants makes this phenomenon difficult to detect without deep sampling of individual lineages. [ABSTRACT FROM AUTHOR]

Objectives To elucidate the evolutionary history of Staphylococcus aureus clonal complex (CC) 8, which encompasses several globally distributed epidemic lineages, including hospital-associated methicillin-resistant S. aureus (MRSA) and the highly prevalent community-associated MRSA clone USA300. Methods We reconstructed the phylogeny of S. aureus CC8 by mutation discovery at 112 genetic housekeeping loci from each of 174 isolates, sampled on five continents between 1957 and 2008. The distribution of antimicrobial resistance traits and of diverse mobile genetic elements was investigated in relation to the isolates' phylogeny. Results Our analyses revealed the existence of nine phylogenetic clades within CC8. We identified at least eight independent events of methicillin resistance acquisition in CC8 and dated the origin of a methicillin-resistant progenitor of the notorious USA300 clone to the mid-1970s. Of the S. aureus isolates in our collection, 88% carried plasmidic rep gene sequences, with up to five different rep genes in individual isolates and a total of eight rep families. Mapping the plasmid content onto the isolates' phylogeny illustrated the stable carriage over decades of some plasmids and the more volatile nature of others. Strikingly, we observed trends of increasing antibiotic resistance during the evolution of several lineages, including USA300. Conclusions We propose a model for the evolution of S. aureus CC8, involving a split into at least nine phylogenetic lineages and a subsequent series of acquisitions and losses of mobile genetic elements that carry diverse virulence and antimicrobial resistance traits. The evolution of MRSA USA300 towards resistance to additional antibiotic classes is of major concern. [ABSTRACT FROM PUBLISHER]

Background. Little is known about the clonality of Staphylococcus epidermidis in the United States, although it is the predominant pathogen in infections involving prosthetic materials, including ventricular assist devices (VADs). Methods. Seventy-five VAD recipients at 4 geographically diverse US cardiac centers were prospectively followed up to 1 year of VAD support. The anterior nares, sternum, and (future) driveline exit site were cultured for S. epidermidis before VAD insertion and at 7 times after surgery. Infection isolates were also collected. Isolates were typed by pulsed-field gel electrophoresis. A subset underwent susceptibility testing and staphylococcal chromosomal cassette mec and multilocus sequence typing. Results. A total of 1559 cultures yielded 565 S. epidermidis isolates; 254 of 548 typed isolates (46%) belonged to 1 of 7 clonal types as defined by pulsed-field gel electrophoresis. These clones were identified in up to 27 people distributed across all 4 cardiac centers. They caused 3 of 6 VAD-related infections. Disseminated clones were more antibiotic resistant than were less prevalent isolates (eg, 79% vs 54% methicillin resistant; P = .0021). Conclusions. This study revealed that healthcare-associated S. epidermidis infection is remarkably clonal. We describe S. epidermidis clones that are highly resistant to antibiotics distributed across US cardiac centers. These clones may have determinants that enhance transmissibility, persistence, or invasiveness. [ABSTRACT FROM AUTHOR]

The skulls of 33 extant cat species were characterized through three-dimensional geometric morphometrics using 20 landmarks. A principal component analysis (PCA) was performed with Procrustes fitted coordinates, and the PC-scores were phylogenetically corrected by independent contrasts method. Three PCs allowed for the definition of five cat skull patterns. PC1: 'snouted/massive-headed cats' (genus Panthera) opposing the 'round-headed small cats' (genus Oncifelis, Prionailurus rubiginosus, Prionailurus bengalensis, among other small cats); PC2: 'tapering-headed cats' ( Neofelis nebulosa, Herpailurus yagouaroundi, Prionailurus planiceps) opposing the 'stout-headed cats' ( Acinonyx jubatus, Uncia uncia, Otocolobus manul, Felis margarita, and Felis nigripes); and PC3: 'low profiled-headed cats' (mostly, Pr. planiceps). A sixth pattern, the 'generalized skull', observed in the Caracal lineage, genus Lynx, Leopardus pardalis, and Catopuma temminckii, indicates a morphological convergence among midsized-cats. The morphological trends 'snouted/massive' and 'round' clearly denote a co-evolution between size and shape. The other skull patterns evolved unrelatedly to the size (i.e. their allometric variations are not a size function). Nevertheless, each species comprises an amalgam of these patterns, so the influence of the size permeates, in some extent, the skull morphology along all cat lineages. The felid ecomorphological fit to hypercarnivory is obvious; however, different skull shapes in same-sized species with similar habits, indicate that the variation in the skull morphology may result from phenotypic fluctuations, whose adaptive value (if indeed there is any) is still obscure. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, , 176-190. [ABSTRACT FROM AUTHOR]

Felids morphology and ecological role as hypercarnivores are quite constant, despite considerable body size variation among species. Skull morphological and functional features of 34 extant cat species were evaluated under a phylogenetic framework of the Felidae. Twenty skull measurements were analysed through Principal Component Analysis to assess the species morphofunctional spaces. Force indexes were obtained from static equilibrium equations to infer jaw mechanics. Correlations between morphological, functional, and ecological traits were tested by phylogenetically independent contrasts. In spite of the general cat-like pattern, specific features on the skulls allowed differentiation among groups. Acinonyx jubatus, for instance, showed a shorter and shallower temporal fossa than other big cats, and their bite functionality is marked by an increased contribution of the masseteric system. A morphofunctional dichotomy between Neotropical and Eurasian/African small cats was detected, and is associated with the major transversal axes of the skulls. According to the contrast analyses, the skull size is correlated with the bite force and prey size, but it is uncorrelated with the variations on jaw mechanics (from temporalis or masseter muscle optimizations). Also, there was no correlation between functional differences on jaw muscles and the ratio of prey weight to cat weight. The efficiency of the jaw apparatus among cats is quite consistent; therefore, the different evolutionary trends of jaw mechanics seem to be caused by the casuistic fixation of phenotypical variations, rather than by specific adaptative selections. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, , 414-462. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the allelic variability of ccrA and ccrB among methicillin-resistant Staphylococcus aureus (MRSA) strains belonging to different genetic lineages and carrying different SCCmec types.Methods: Internal fragments from both genes were obtained by PCR amplification with pairs of degenerate primers and the nucleotide sequence was determined for both strands. Nucleotide sequences were aligned and the phylogenetic trees were reconstructed.Results: The homology scores obtained confirmed the very close relationships among ccrAB alleles associated with each SCCmec type, which further validate this locus as a good target for SCCmec typing strategies. Using this strategy, particularly for the ccrB gene, SCCmec types with the same ccrAB allotype, as detected by PCR, could be discriminated and some strains with non-typeable ccrAB loci were resolved.Conclusions: We propose that sequencing an internal fragment of ccrB is a strategy for SCCmec typing that may be easily incorporated into other sequence-based MRSA typing strategies, such as multi-locus sequence typing and spa typing. [ABSTRACT FROM AUTHOR]

Persons with acquired immune deficiency syndrome (AIDS) who use drugs appear to be at increased risk for colonization and infection with Staphylococcus aureus. Little is known about the nature of and risk factors responsible for this association. This study is among the first to prospectively follow carriage and infection in this uniquely high-risk population. We prospectively followed the cases of 75 patients with AIDS in a residential drug treatment facility and screened for S. aureus nasal colonization and infection. Thirty-seven baseline cultures (49%) were positive for S. aureus, and 81% of subjects were colonized at least once during the study. Thirteen subjects experienced 17 infections. Pulsed-field gel electrophoresis and sequence-based typing methods revealed that 244 (92%) of the isolates belonged to either clonal type A or B. Clonal type A was methicillin-susceptible. Clonal type B consisted of 3 main subtypes (B1, B2, and B3), all with the same allelic profile (5T8) and staphylococcal protein A gene (spa) type (7). Of note, subtype B1 was methicillin-susceptible (5T8 and spa type 7), lacking mecA, whereas the other B clones were methicillin-resistant. Both clones were resistant to trimethoprim-sulfamethoxazole. Clonal type B isolates were relatively resistant, suggesting prior exposure to the health care setting. This study demonstrates a sustained high rate of S. aureus carriage and infection. It demonstrates the capacity of unique methicillin-resistant S. aureus clones with an established linkage to earlier outbreaks of methicillin-resistant S. aureus, as well as to human immunodeficiency virus-infected subjects, to persist in this residential setting. It also illustrates the apparent genetic instability or transmissibility of the staphylococcal chromosomal cassette mec type IV element. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) emerged in the early 1960s after the acquisition of the methicillin resistance gene mecA, which is carried by the staphylococcal cassette chromosome mec (SCCmec). MRSA seemed to have arisen by multiple introductions of SCCmec into successful methicillin-susceptible S. aureus (MSSA) lineages. MRSA is one of the most common agents of nosocomial infections worldwide increasing the cost and mortality compared to MSSA infections. Little by little, MRSA has acquired resistance to all antibiotics available in clinical practice, which complicates treatment. This situation was further aggravated by the recent reports of vanA-mediated vancomycin-resistant S. aureus. As a reaction to the emergence and spread of multidrug-resistant MRSA worldwide, international surveillance systems such as the CEM/NET initiative have been created. The characterization of over 3000 MRSA isolates from different regions of the world evidenced the existence of only a few epidemic clones spread worldwide, namely the Iberian, Brazilian, Hungarian, New York/Japan, Pediatric and EMRSA-16 clones. It was found that in surveillance or evolutionary studies strains should be characterized by a combination of different typing methods, namely pulsed-field gel electrophoresis, multi-locus sequence typing and SCCmec typing. In recent years, community-acquired MRSA (CA-MRSA) has become a growing public health concern. However, although many authors reported the emergence of CA-MRSA isolates, a standard definition has not been created and the prevalence of MRSA among persons without risk factors seems to remain very low. CA-MRSA has distinct properties compared to epidemic nosocomial MRSA clones and its origin is still unclear. Certain authors suggest there is MRSA transmission from the hospital setting to the community, namely transfer of nosocomial MRSA minor clones or sporadic isolates showing a high degree of similarity with CA-MRSA; others believe CA-MRSA strains represent new acquisitions of SCCmec DNA in susceptible backgrounds. Many questions concerning this extraordinarily versatile and threatening pathogen remain unanswered, needing future investigation. [Copyright &y& Elsevier]

Several lines of epidemiological and microbiological studies point to the multiple and critical roles of the nasopharynx of children—particularly those of pre-school age and attending day-care centres (DCCs)—in the emergence and spread of drug-resistant Streptococcus pneumoniae (DRP). A systematic yearly surveillance of the nasopharyngeal flora of children attending DCCs has been carried out in Lisbon since 1996. Molecular typing of several hundred DRP isolates showed that the great majority of DRP were represented by a relatively few clonal types that were frequently carried by many children in geographically distant DCCs and over several years of surveillance. The same epidemic DRP clones were also frequent among pneumococci causing both paediatric and adult disease worldwide. Penicillin-resistant pneumococci carry sequences of heterologous origin in their pbp genes and also in the recently identified murM: a gene essential for expression of penicillin resistance and for the unique cell wall structure of penicillin-resistant pneumococci. Virtually all DRP express only a limited number (five or six) of the very large genetic repertoire (up to 90) of serotypes available for this bacterial species and the serotypes of drug-resistant strains happens to be the same as the serotypes of drug-susceptible pneumococci that most frequently colonize pre-school age children. These observations strongly suggest that the nasopharynx of children is an important global ecological reservoir of DRP and may also play a critical role as the favoured anatomical site for the evolution of DRP. [ABSTRACT FROM PUBLISHER]

After the introduction and extensive dissemination of the multidrug-resistant Streptococcus pneumoniae clone Spain[sup 6B]-2 between 1989 and the early to mid-1990s, the prevalence of pneumococcal isolates expressing intermediate resistance to penicillin, mainly of capsular types 6, 19, and 23, also began to increase in Iceland. The purpose of this study was to investigate whether these isolates originated in Iceland or represented strains imported to the country. Isolates were characterized by pulsed-field gel electrophoresis; multilocus sequence typing; determination of pbp1a, pbp2b, and pbp2x gene restriction patterns; and partial sequencing of these pbp genes. The results indicate that, although singular events suggesting horizontal transfer of pbp genes (and capsular genes) were detected, the majority of clones circulating in the country had genetic backgrounds also detected abroad. The major mechanism of dissemination of penicillin resistance in Iceland appears to be the repeated introduction of multiple lineages, followed by clonal spread. [ABSTRACT FROM AUTHOR]

Six drug-resistant Streptococcus pneumoniae clones were previously identified from day care centers in Portugal, primarily on the basis of common pulsed-field gel electrophoresis (PFGE) patterns. These clones were susceptible to penicillin or had only very low-level resistance to it (most MICs, ≤0.25 µg/mL) and accounted for a large proportion (35%) of all drug-resistant pneumococci colonizing the nasopharynx of healthy children attending day care. Five of the 6 clones were identified among pneumococcal clinical isolates collected in other countries. In this study, we applied multilocus sequence typing (MLST) to describe the genetic background of these clones. MLST confirmed previous findings obtained by PFGE and allowed for the extension of the international clonal relationships by showing that each of the 6 clones was internationally disseminated and was able to cause pneumococcal disease. [ABSTRACT FROM AUTHOR]

Over half (259/503) of drug-resistant (DR) pneumococci colonizing healthy children attending day care centers in Lisbon were identified by molecular typing methods as representatives of several internationally spread clones. These included the 2 penicillin-resistant pandemic Spanish/USA and French/Spanish clones (21% of all DR pneumococci) and 5 new lineages with unusual antibiotypes (accounting for an additional 30% of all DR pneumococci). The most characteristic feature of the latter group was the high frequency of resistance to macrolides and tetracycline and very low or no resistance to penicillin. These observations provide support for the notion that the nasopharyngeal flora of children in day care centers may be a global reservoir of worldwide prevalent strains of DR pneumococci. Copyright © 2000 The University of Chicago [ABSTRACT FROM AUTHOR]

To define the stability of methicillin-resistant Staphylococcus aureus (MRSA) in vivo, 22 isolates collected at one New York institution in 1989 and 1990 were studied. All 22 belonged to one of two distinct methicillin-resistant phenotypes (class 3 or 2), which were precisely identified as belonging to two distinct genotypes. Genotypic classification was based on restriction analysis of chromosomal DNA with EcoRI and HindIII and Southern analysis of ClaI digests using two DNA probes. One was specific for the mec gene; the other was specific for transposon Tn554. The findings suggest that the MRSA isolates studied were representative of two genetically distinct MRSA “clones,” each with a unique strain-specific methicillin-resistant phenotype that is stable under the conditions of invasive disease, carriage, and spread from patient to patient. [ABSTRACT FROM PUBLISHER]

Reports on the Project Megapoles, a public health network created to look for ways to achieve better health and reducing differences in health between capital cities in Europe. Public health problems in Europe's metropolitan areas; Aims of Megapoles; Common objectives of the sub-networks within Megapoles.

A letter to the editor is presented that discusses trichoscopy as an additional tool for the differential diagnosis of tinea capitis.