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)