Evaluation of aztreonam and ampicillin vs. amikacin and ampicillin for treatment of neonatal bacterial infections.

In a prospective randomized, open study we evaluated aztreonam (AZ) for treatment of neonatal bacterial infections. There were 147 patients enrolled in the study; 75 received AZ and ampicillin (AMP) and 72 amikacin (AM) and AMP (conventional therapy). Twenty-eight AZ/AMP-treated patients and 32 conventionally treated patients had bacteriologically documented infections caused by gram-negative enteric bacilli or Pseudomonas species. Treatment groups were comparable in age, clinical status, and type and severity of underlying disease at the time of enrollment. Bronchopneumonia and infections caused by Pseudomonas species occurred significantly more often in AM/AMP-treated patients compared with patients given AZ/AMP. Sepsis was documented in 83% of patients in each treatment group and Gram-negative enteric bacilli and Pseudomonas species were the principal pathogens. Median peak serum bactericidal titers against the etiologic agent were 1:64 for the AZ/AMP and 1:16 for AM/AMP-treated patients. Case fatality rates resulting from the primary infection were 7 and 22% (P = 0.011), superinfection occurred in 39% and 34% and treatment failure occurred in 7 and 28% (P = 0.036) of the AZ/AMP and AM/AMP-treated patients, respectively. No clinical adverse reactions were observed in either group. Based on these results aztreonam appears to be at least as effective as and possibly more effective than amikacin when used initially with ampicillin for empiric treatment of neonatal bacterial infections.