| Microbial Epidemiology Rosario Mato Tel: + 351 4469834 Fax: + 35121 4428766 e-mail:rmato@itqb.unl.pt |
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Enterococci traditionally considered as Gram-positive commensal bacteria of animal and human gastrointestinal tract, are now recognized as microorganism capable to cause life-threatening infections in humans. The problem is highlighted by the emergence of multi-drug resistant strains, as the case of the resistance to vancomycin, the last line of defense in many Gram-positive bacterial infections. In spite of the increasing number of cases of enterococcal infection and the remarkable ability of these organisms to resist antibiotics, relatively little about their pathogenesis is known compared to what is known about some other gram-positive cocci. The acquisition of mobile elements and exogenous DNA have played an important role on the evolution and pathogenesis of these microorganisms, contributing to the rapid acquisition and dissemination of both drug resistance genes to the most clinically relevant antimicrobials and virulence determinants, which enhanced probably the enterococcal fitness, particularly in the hospital environment. This laboratory is also focused on the epidemiology of beta-haemolytic streptococci, another Gram-positive bacterium, colonizing the oropharynx and nasopharynx of healthy children attending day care centers, as well as the impact of the 7-valent pneumococcal conjugate vaccine on the streptococcal nasopharyngeal flora other than
Streptococcus pneumoniae.
