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In this study, we analyzed the antimicrobial resistance properties and T antigenic types of 511 isolates collected in Lisbon district, Portugal, from throat swabs of healthy subjects (n = 341), during 2000–2002 and from diverse infection sites (n = 170) of outpatients and inpatients, during 1999–2002. Erythromycin resistance was higher in tonsillitis/pharyngitis (27.4%) and skin infection isolates (21.1%), than in carriage and invasive isolates (≤10%). Differences in erythromycin resistance among children and adults were noticed only for carriage isolates (9.3% in children and 21.1% in adults). Most erythromycin-resistant isolates from carriage (82.4%) and tonsillitis/pharyngitis (71.9%) showed the M phenotype. All M phenotype isolates (n = 53) carried mef(A), whereas all MLSB phenotype isolates (n = 19) carried erm(B) and not erm(A). Resistance to tetracycline [mediated by tet(M) in most isolates] was ≤6% in tonsillitis/pharyngitis and carriage isolates, 36.8% in skin infection isolates, and 44.1% in invasive isolates. The M phenotype increased since 2000, linked to a decrease of tetracycline resistance, and was predominantly associated with T1 in 2000–2001 and T12 in 2002 among carriage isolates, and with T8/25/Imp19 through 2000–2002 among tonsillitis/pharyngitis isolates. The majority (53%) of the tetracycline-resistant invasive isolates were nontypable. All isolates were susceptible to penicillin and chloramphenicol. This study showed that tetracycline and macrolide resistance frequency and phenotypes differ among GAS from various origins and changed over time. Moreover, T typing suggested that most drug-resistant isolates causing oropharyngeal carriage are distinct from the majority of isolates causing noninvasive and invasive infection.

A total of 143 methicillin-resistant coagulase-negative staphylococci (MR-CNS) collected between 1998 and 2000 at the University Hospital of Patras, Greece, were characterized by antibiogram and genomic typing to define the clonal types endemic in this hospital and their evolution during the 3-year period. These isolates corresponded to 93 methicillin-resistant Staphylococcus epidermidis (MRSE) and 50 other MR-CNS, which were isolated from patients in different wards, exclusively from blood and catheter tips cultures. Pulsed-field gel electrophoresis (PFGE) of SmaI macrofragments and hybridization of ClaI digests with mecA and murE DNA probes were performed. The application of these methodologies demonstrated the existence, persistence and spread of MRSE, MR-Staphylococcus haemolyticus, and MR-Staphylococcus hominis clones in this hospital, whereas the SmaI/murE hybridization pattern was shown to be a valuable tool for the MRSE identification.

ABSTRACTPulsed-field gel electrophoresis (PFGE) of SmaI macrofragments and hybridization of ClaI digests with the mecA- and Tn554-specific DNA probes were used to define the endemic clones of methicillin-resistant Staphylococcus aureus(MRSA) among strains collected in 1993 and 1998 to 2000 at the University Hospital of Patras, Patras, Greece. Representatives of each clonal type were analyzed by spaAtyping, multilocus sequence typing (MLST), and staphylococcal chromosomal cassette mec(SCCmec) typing. The results indicated the existence of two successive international MRSA clones: (i) a clonal type with PFGE type A, sequence type (ST) 30 (ST30), and SCCmectype IV, which was very similar to a clone widely spread in the United Kingdom, Mexico, and Finland, and (ii) a clonal type with PFGE type B, ST239, and SCCmecIII, which was related to the Brazilian clone. Both clones seem to be widespread in Greece as well. A novel MRSA clone is also described and is characterized by a new MLST type (ST80) associated with SCCmectype IV and with the presence of Panton-Valentine leukocidin genes.

ABSTRACTOne hundred thirty-two methicillin-resistant Staphylococcus aureus(MRSA) isolates recovered from patients with S. aureusinfections between January 1998 and February 1999 in two hospitals, one located in Taipei, Taiwan, and another in Nanjing, People's Republic of China, were examined for antibiotic susceptibility and for clonal type by a combination of three methods: hybridization of ClaI restriction digests with mecA- and Tn554-specific DNA probes and pulsed-field gel electrophoresis of chromosomal SmaI digests. Selected isolates representing each clonal type were also analyzed by spaAtyping, multilocus sequence typing, and a multiplex PCR method capable of identifying the structural type of the staphylococcal cassette chromosome mec(SCCmec) carried by the bacteria. The overwhelming majority of isolates (126 of 132 or 95%) belonged to minor variants of a single clonal type resembling the Brazilian and Hungarian epidemic MRSA clones, which showed a common spaAtype and which were either sequence type 239 (ST239) or ST241 (a single-locus variant of ST239) in association with SCCmectype III or IIIA.

The first study on the molecular characterization of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Colombia was performed as part of a global surveillance established by the CEM/NET Initiative, under Project RESIST. Seventy-six MRSA isolates recovered from five hospitals during 1996-1998 were analyzed by the hybridization of ClaI restriction digests with mecA- and Tn554-specific probes, and by pulsed-field gel electrophoresis (PFGE) of chromosomal SmaI digests. All MRSA isolates, with one exception, belonged to a single clonal type II::NH::D. This clone, which was previously described among MRSA isolates recovered in the early 1990s in European and New York and South American hospitals, showed resistance to β-lactam antibiotics only and appeared to be associated almost exclusively with pediatric infections ("Pediatric clone" of MRSA). While sharing identical molecular typing properties with the Pediatric clone, the Colombian isolates differed by extensive multidrug resistance and were recovered from patients of all ages. It is also noteworthy that the Brazilian clone of MRSA (XI::B::B), another multidrug-resistant international clone currently widely spread in Brazil, Argentina, Uruguay, Chile, and also in several European countries, was completely absent from this set of isolates from Colombia.

Surveillance in two medium-size (250-300 beds) hospitals located in the most populated islands of Cape Verde was undertaken in July 1997 in order to obtain data concerning nasal carriage of staphylococci. Nasal swabs (172) taken from inpatients and health care workers (HCW) from different internment services yielded 68 Staphylococcus aureusand 105 coagulase-negative staphylococcal (CNS) isolates, demonstrating extensive colonization of both inpatients and HCW by S. aureus(carriage rate 41%) and CNS (carriage rate 65%). The most frequent CNS species were S. epidermidisand S. haemolyticus. Three species - S. aureus, S. epidermidis, and S. sciuri- were recovered from wound swabs. The antibiotic susceptibility profiles of S. aureusand CNS differed sharply: all 68 S. aureuswere resistant to penicillin but were fully susceptible to oxacillin as well as the other antimicrobial agents tested - gentamicin; erythromycin, except for three strains; ciprofloxacin; sulfamethoxazole-trimethoprim, except for two strains; vancomycin; and amoxicillin/clavulanate. In contrast, most (91/105) of CNS were resistant to both penicillin and oxacillin, and a variable but substantial proportion of CNS isolates also carried multiresistant traits to gentamicin, erythromycin, sulfamethoxazole-trimethoprim, and amoxicillin/clavulanate. The analysis by PFGE of the methicillin-susceptible S. aureus(MSSA) and the methicillin-resistant S. epidermidis(MRSE) strains provided evidence for extensive cross-infection and cross-colonization from HCW to patients.

ABSTRACTMolecular surveillance studies have documented the extensive spread of methicillin-resistant Staphylococcus aureus(MRSA) clones. Studies carried out by Centro de Epidemiologia Molecular-Network for Tracking Gram-Positive Pathogenic Bacteria (CEM/NET) led to the identification of two international multidrug-resistant strains, which were designated as the Iberian and Brazilian MRSA clones and which were defined by multiple genomic typing methods; these included ClaI restriction digests hybridized with mecA- and Tn554-specific DNA probes and pulsed-field gel electrophoresis (PFGE). The genotypic characteristics of these clones are distinct: the Iberian clone is defined asmecAtype I, Tn554type E (or its variants), and PFGE pattern A (I:E:A), whereas the Brazilian clone is defined asmecAtype XI (or its variants), Tn554type B, and PFGE pattern B (XI:B:B). In this study, we characterized 59 single-patient isolates of MRSA collected during 1996 and 1997 at seven hospitals located in Prague and five other cities in the Czech Republic by using the methodologies mentioned above and by using ribotyping ofEcoRI and HindIII digests hybridized with a 16S-23S DNA probe. The Brazilian MRSA clone (XI:B:B) was the major clone (80%) spread in two hospitals located in Prague and one located in Brno; the Iberian MRSA clone (I:E:A or its variant I:DD:A), although less representative (12%), was detected in two hospitals, one in Prague and the other in Plzen. Almost all the strains belonging to clone XI:B:B (45 of 47) corresponded to a unique ribotype, E1H1, whereas most strains of the I:E:A and I:DD:A clonal types (6 of 7) corresponded to ribotype E2H2.