RESUMEN

Staphylococcus lugdunensis has emerged as a significant human pathogen, with distinct clinical and microbiological characteristics. Our goal was to identify the virulence factors in S. lugdunensis recovered from infected patients of two Greek hospitals during a six-year period (2008-2013). A collection of 38 S. lugdunensis was tested for biofilm formation, antimicrobial susceptibility, clonal distribution, virulence factors (ica operon, fbl, atlL, vwbl, slush) and antibiotic resistance genes (mecA, ermC) carriage. Strains were classified into pulsotypes by pulsed-field gel electrophoresis (PFGE) of SmaI DNA digests. The majority (22) was isolated from skin and soft tissue infections (SSTIs), nine from deep-sited infections (DSIs), including three bacteraemias and seven from prosthetic device-associated infections (PDAIs). All isolates were oxacillin-susceptible, mecA-negative and fbl-positive. The highest resistance rate was detected for ampicillin (50%), followed by erythromycin and clindamycin (18.4%). Fourteen isolates (36.8%) produced biofilm, whereas 26/38 (68.4%) carried the ica operon. Biofilm formation was more frequent in isolates from PDAIs. Thirty-six strains (94.7%) carried atlL and 31 (81.6%) carried vwbl, whereas slush was detected in 15 (39.5%). PFGE revealed a low level of genetic diversity: strains were classified into seven pulsotypes, with two major clones (C: 22 and D: nine strains). Type C strains recovered from all infection sites prevailed in biofilm formation and ermC carriage, whereas type D strains associated with SSTIs and DSIs carried more frequently vwbl, slush or both genes. Despite susceptibility to antimicrobials, the clonal expansion and carriage of virulence factors, combined with biofilm-producing ability, render this species an important pathogen that should not be ignored.

Asunto(s)

Infecciones Estafilocócicas/microbiología , Staphylococcus lugdunensis/genética , Staphylococcus lugdunensis/aislamiento & purificación , Factores de Virulencia/genética , Adulto , Antibacterianos/farmacología , Biopelículas/crecimiento & desarrollo , Análisis por Conglomerados , Farmacorresistencia Bacteriana , Electroforesis en Gel de Campo Pulsado , Femenino , Variación Genética , Genotipo , Grecia , Hospitales , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Tipificación Molecular , Staphylococcus lugdunensis/clasificación , Staphylococcus lugdunensis/patogenicidad

RESUMEN

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of both healthcare-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA) infections. Severe MRSA infections have been associated with the virulence factor Panton-Valentine leukocidin (PVL). The aim of this study was to investigate susceptibility patterns, the presence of toxin genes, including that encoding PVL, and clonality among MRSA isolates collected from patients in Greece over a 12-year period. MRSA isolates were collected from January 2001 to December 2012 from six different hospitals. Antibiotic susceptibility was determined with the disk diffusion method and the Etest. The presence of the toxic shock syndrome toxin-1 gene (tst), the enterotoxin gene cluster (egc) and the PVL gene was tested with PCR. The genotypic characteristics of the strains were analysed by SCCmec and agr typing, and clonality was determined with pulsed-field gel electrophoresis and multilocus sequence typing. An increasing rate of MRSA among S. aureus infections was detected up to 2008. The majority of PVL-positive MRSA isolates belonged to a single clone, sequence type (ST)80-IV, which was disseminated both in the community and in hospitals, especially during the warmest months of the year. Carriage of tst was associated with ST30-IV, whereas egc was distributed in different clones. CA-MRSA isolates were recovered mainly from skin and soft tissue infections, whereas HA-MRSA isolates were associated with surgical and wound infections. During the period 2001-2012, ST80-IV predominated in the community and infiltrated the hospital settings in Greece, successfully replacing other PVL-positive clones. The predominance of ST239-III in HA-MRSA infections was constant, whereas new clones have also emerged. Polyclonality was statistically significantly higher among CA-MRSA isolates and isolates from adult patients.

Asunto(s)

Epidemias , Staphylococcus aureus Resistente a Meticilina/clasificación , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Adulto , Antibacterianos/farmacología , Toxinas Bacterianas/genética , Niño , Preescolar , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/microbiología , Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Femenino , Genotipo , Grecia/epidemiología , Humanos , Masculino , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Pruebas de Sensibilidad Microbiana , Epidemiología Molecular , Tipificación Molecular , Reacción en Cadena de la Polimerasa , Factores de Virulencia/genética

RESUMEN

We carried out a comprehensive prospective study of 26 pregnancies complicated by preterm rupture of the membranes. Microbiological assessment included cultures for aerobic and anaerobic bacteria, Mycoplasmas, Chlamydia, Trichomonas and fungi from: high vaginal and cervical swabs, maternal blood and urine, amniotic fluid and fetal blood on admission and finally, placenta and umbilical cord = after delivery. The group with positive cultures (n 16), was compared with the group with negative cultures = (n 10) in terms of gestational age at labour, latent phase after membrane rupture and fetal and neonatal morbidity and mortality. All patients with positive cultures delivered before 32 weeks and their neonates had evidence of infection. Three intrauterine deaths occurred in this group and 12/13 (86%) of the live neonates were admitted to the neonatal intensive care unit. The 10 (38%) patients of the group with negative cultures delivered after 32 weeks, had no perinatal deaths, and only two were admitted to neonatal intensive care. The median latent phase differed between these two groups (4.5 vs. 53.5 days, P 0.01), as did the median gestational age at labour (28 vs. 36 4 weeks, P 0.01). A positive amniotic fluid or fetal blood culture in the clinical setting of preterm rupture of the membranes indicates labour onset within a few days. Intrauterine infection with fetal sepsis is accompanied by high neonatal infectious morbidity (100%) and mortality (30%).