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During 1991 to 1998 at least one Stenotrophomonas maltophilia pulmonary infection was observed in 25 (24%) of 104 cystic fibrosis (CF) patients at the same unit of our hospital in Spain. Ribotyping and pulse-field gel electrophoresis (PFGE) characterization of 76 S. maltophilia isolates from these patients indicated an overall clonal incidence of 47.1%, reflecting new strains in 44% of patients with repeated positive cultures for S. maltophilia. Six patients with repeated episodes were persistently colonized (>6 months) with the same strain. S. maltophilia bacterial counts were higher (geometric mean, 2.9 x108 cfu/mL) in patients with repeated episodes than in those with a single episode (8.4 x104 cfu/mL, p16 years of age).

BACKGROUND: Community-associated methicillin-resistant Staphylococcus aureus-(CA-MRSA) strains have emerged in Argentina. We investigated the clinical and molecular evolution of community-onset MRSA infections (CO-MRSA) in children of Córdoba, Argentina, 2005-2008. Additionally, data from 2007 were compared with the epidemiology of these infections in other regions of the country. METHODOLOGY/PRINCIPAL FINDINGS: Two datasets were used: i) lab-based prospective surveillance of CA-MRSA isolates from 3 Córdoba pediatric hospitals-(CBAH1-H3) in 2007-2008 (compared to previously published data of 2005) and ii) a sampling of CO-MRSA from a study involving both, healthcare-associated community-onset-(HACO) infections in children with risk-factors for healthcare-associated infections-(HRFs), and CA-MRSA infections in patients without HRFs detected in multiple centers of Argentina in 2007. Molecular typing was performed on the CA-MRSA-(n: 99) isolates from the CBAH1-H3-dataset and on the HACO-MRSA-(n: 51) and CA-MRSA-(n: 213) isolates from other regions. Between 2005-2008, the annual proportion of CA-MRSA/CA-S. aureus in Córdoba hospitals increased from 25% to 49%, P

Objectives: To ascertain the participation of topoisomerase mutations in the development of ciprofloxacin resistance in isogenic Stenotrophomonas maltophilia mutants.Methods: gyrAB and parCE sequences in three paired in vivo isogenic ciprofloxacin-susceptible (MIC range 0.54 mg/L) and resistant (16128 mg/L) S. maltophilia strains (PFGE-characterized) sequentially isolated from three patients, and their corresponding in vitro mutants (ciprofloxacin MIC range 2>128 mg/L), were studied. Efflux phenotype was also investigated.Results: Despite different quinolone susceptibilities, each paired clinical strain displayed identical gyrAB and parCE sequences as well as their corresponding in vitro mutants. Up to 50% (18/36) of in vitro mutants displayed a positive efflux phenotype when nalidixic acid was combined with MC-207,110, while 6% (2/36) showed the phenotype when exposed to nalidixic acid and reserpine. Carbonyl cyanide m-chlorophenylhydrazone or arsenite failed to alter quinolone MICs.Conclusions: The increase of ciprofloxacin MICs in in vivo and in vitro isogenic S. maltophilia mutant strains was not related to quinolone resistance determining region mutations. Highly effective efflux mechanisms might preserve topoisomerase targets from a ciprofloxacin challenge in S. maltophilia. [ABSTRACT FROM AUTHOR]

Objectives: Since 1998 the European Commission has funded EARSS. We present the antibiotic susceptibility results of invasive Staphylococcus aureus obtained in Spain (2000–2002).Material and methods: Forty hospitals participated in this study, covering nearly 30% of the Spanish population. All blood isolates of S. aureus were included. Laboratories used their usual methods to perform microbiological studies. Annual external quality controls were carried out. A questionnaire with hospital, patient and specimen data was completed for each isolate. Results were included in a database and analysed with WHONET 5 software.Results: Invasive S. aureus was isolated in 3113 patients. Resistance was 24.5% to oxacillin, 25.4% to ciprofloxacin, 25.2% to erythromycin and 12.1% to gentamicin. Gentamicin resistance decreased from 16.6% (2000) to 9.7% (2002). Multiresistance was observed in 68.1% of oxacillin-resistant isolates. More prevalent multiresistance profiles consisted of oxacillin–ciprofloxacin–erythromycin–gentamicin (7.4%) and oxacillin–ciprofloxacin–erythromycin (7.1%). Oxacillin resistance was significantly higher in nosocomial isolates than in those implicated in community-onset infections (26.7% versus 14.2%), in isolates from adults than in those from children (27.3% versus 4.7%), in hospitals with >500 beds than in those with <500 beds (31.1% versus 18.3%) and in isolates from Intensive Care Units than in those from other departments (39.3% versus 24%). Decreased susceptibility to vancomycin was not detected.Conclusions: In Spain, S. aureus blood isolates present a high prevalence of resistance to oxacillin, ciprofloxacin and erythromycin, as well as a high prevalence of multiresistance. Oxacillin resistance remains stable but varies in relation to hospital size, patient age, hospital department and place of infection acquisition. [ABSTRACT FROM AUTHOR]