Yersinia pestis Anaerobic micro-organisms Mobiluncus Other micro-organisms Chlamydia trachomatis ($) Chlamydia pneumoniae ($) Mycoplasma hominis ($) Mycoplasma pneumoniae ($) SPECIES FOR WHICH ACQUIRED RESISTANCE MAY BE A PROBLEM Aerobic Gram-positive micro-organisms Enterococcus faecalis ($) Staphylococcus spp. *(2) 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.