Efficacy of sulbactam alone and in combination with ampicillin in nosocomial infections caused by multiresistant Acinetobacter baumannii

From March 1995 to March 1997, sulbactam was prospectively evaluated in pat ients with non-life-threatening multiresistant Acinetobacter baumanniii inf ections. During this period, 47 patients were treated with sulbactam; of th em, five were excluded because they had received less than or equal to 48 h of sulbactam therapy. A total of 42 patients, 27 males and 15 females with a mean age of 60 +/- 15 years, were finally evaluated. Infections were as follows: surgical wound, 19; tracheobronchitis, 12; urinary tract, 7; cathe ter-related bacteraemia, 2; and pneumonia, 2. Eighteen patients received in travenous sulbactam alone (1 g every 8 h) and 24 patients received intraven ous sulbactam/ampicillin (1 g:2 g every 8 h) with no major adverse effects. Of the 42 patients, 39 improved or were cured and showed A. baumannii erad ication and one patient had persistence of wound infection after 8 days of sulbactam/ampicillin requiring surgical debridement. Two patients died afte r 3 clays of therapy (ons of the deaths was attributable to A. baumannii in fection). The in-vitro activity of the sulbactam/ampicillin combination was by virtue of the antimicrobial activity exhibited by sulbactam. Killing cu rves showed that sulbactam was bacteriostatic; no synergy was observed betw een ampicillin and sulbactam. Our results indicate that sulbactam may prove effective for non-life-threatening A. baumannii infections. Its role in th e treatment of severe infections is unknown. However, the current formulati on of sulbactam alone may allow its use at higher doses and provide new pot ential synergic combinations, particularly for those infections by A. bauma nnii resistant to imipenem.