Gram-negative non-fermentative aerobic bacilli are becoming increasingly more involved in
nosocomial infections. It has generally been recognised that the members of the Acinetobacter genus are among the most common agents responsible for severe
hospital infections; their clinical importance has increased due to the development of antibacterial resistance mechanisms by these organisms. Over the last two decades the antibacterial armamentarium has progressed significantly and newer broad spectrum
antibiotics have been used during
therapy of
hospital infections due to
drug-resistant Acinetobacter spp. Despite various mechanisms of resistance to
beta-lactams,
aminoglycosides,
fluoroquinolones developed by these organisms, the control of
Acinetobacter infections can be effected by the use of several
antibiotic combinations in 'conventional'
antibiotic therapy. Recent surveys have pointed out the importance of using combinations of 2-amino-5-thiazolyl
cephalosporins, or
imipenem with
aminoglycosides, or alpha-carboxy-
penicillins (
ticarcillin) combined with
beta-lactamase inhibitors. Amongst the latter drugs, the place of
sulbactam should be redefined thanks to its intrinsic activity against the Acinetobacter species, associated with its inhibitory power against
beta-lactamases. The
fluoroquinolones were initially very active against
Acinetobacter infections, but resistance to this major class of drugs has occurred very rapidly. However, newer compounds of this class with increased anti-Acinetobacter activities can be used in combinations with
beta-lactams or
aminoglycosides. The potential role of
rifampicin is still underestimated for the treatment of
Acinetobacter infections despite promising in vitro activity. Novel derivatives of
cephalosporins,
carbapenems,
fluoroquinolones, or completely new
antibiotic classes, of which several
investigational drugs seem promising, may constitute the future of
antibiotic therapy and hence the treatment of
Acinetobacter infections.