164 Aerobic Gram-negative micro-organisms Acinetobacter baumannii+ Burkholderia cepacia+* Campylobacter spp. +* Citrobacter freundii* Enterobacter aerogenes Enterobacter cloacae* Escherichia coli* Klebsiella oxytoca Klebsiella pneumoniae* Morganella morganii* Neisseria gonorrhoeae * Proteus mirabilis* Proteus vulgaris* Providencia spp.