Antimicrobial resistance patterns in respiratory pathogens isolated in an Italian university hospital during a period of eight years: a statistical analysis

The antimicrobial resistance patterns of respiratory pathogens isolated during an 8-year period (1990-1997) in an Italian hospital from patients with bronchopulmonary infections were investigated. A global variation in the resistance of Staphylococcus aureus to all relevant antibiotics was observed during the years 1990-1997. With the exception of penicillin and amoxicillin, to which Staphylococci were always resistant, and vancomycin, to which they were always susceptible, in the first period (1990-1992) the percentage of resistance to beta-lactams, aminoglycosides, macrolides, fluoroquinolones and cotrimoxazole was about 15%, while in the last period (1993-1997) it was about 35%. No global variation in resistance to the antimicrobials examined during the study period was observed for gram-negative bacteria. The percentages of resistance to the more recent beta-lactams, aminoglycosides and fluoroquinolones were generally less than 10% for the KES group, less than 20% for Pseudomonas aeruginosa, and less than 30% for other Pseudomonas species. A high percentage of resistance was observed for the KES group to amoxicillin + clavulanic acid (60%) and to cefoxitin (48%).