IS STREPTOCOCCUS-PNEUMONIAE A NOSOCOMIALLY ACQUIRED PATHOGEN

Streptococcus pneumoniae is most prominently a major cause of communit y-acquired infections of the respiratory tract, central nervous system , and bloodstream, but there is an increasing interest in its role in the epidemiology of hospital-acquired infections. Penicillin-resistant pneumococcal strains appeared 3 decades ago and now are present world wide, often displaying multiple resistance due to antibiotic selective pressure. Horizontal spread can cause either sporadic cases or hospit al outbreaks, primarily in younger children and elderly patients. Pneu mococcal transmission from one patient to another can be documented by polymerase chain reaction or pulsed-field gel electrophoresis typing. Nosocomial acquisition of infection, along with pediatric age, previo us hospitalization, and previous beta-lactam therapy, are the main ris k factors significantly associated with penicillin-resistant pneumococ cal infections. Nosocomial acquisition also is associated with higher mortality from pneumococcal disease. The importance of penicillin resi stance as a risk factor significantly associated with higher mortality from pneumococcal infection is found in some studies, but not in othe rs. Mortality from pneumococcal pneumonia is approximately the same fo r human immunodeficiency virus (HIV)-infected patients without acquire d immunodeficiency syndrome (AIDS) as for HIV-negative subjects, but i t is significantly higher in AIDS patients. Penicillin-resistant strai ns are involved in the vast majority of hospital outbreaks, whether pr esenting as clinically manifest infection or a simple colonization. Pn eumococcal vaccination is recommended universally in order to lower th e incidence of invasive infection, although a number of problems can l imit its effectiveness.