Chloramphenicol This product is an antibiotic of the chloramphenicol class. It has a broad-spectrum anti-microbial effect in vitro, including some aerobic Gram-negative and Gram-positive bacteria, anaerobic bacteria, Rickettsia spp., Spirochetes and Chlamydia spp. It has bactericidal effect on the following bacteria: such as Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus meningitis, as well as Staphylococcus aureus, Staphylococcus pyogenes, Streptococcus griseus, as well as group B hemolytic streptococcus, Escherichia coli, Klebsiella pneumoniae, as well as Salmonella typhi, Paratyphoid, Salmonella, etc. It has antibacterial effect. There are also usually chloramphenicol-resistant Pseudomonas aeruginosa, Bacillus spp. and some methicillin-resistant staphylococci and enterococci.