Erythromycin antibiotic crystals, LM

Light micrograph (LM) of Erythromycin (antibiotic) crystals. Erythromycin is a macrolide antibiotic that has an antimicrobial spectrum similar or slightly wider than penicillin, and is often used for people who have an allergy to penicillin. Erythromycin prevents bacteria from growing, by interfering with their protein synthesis. Erythromycin binds to the subunit 50S of the bacterial ribosome, and thus inhibits the translocation of peptides. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma. It is also used to treat outbreaks of chlamydia, syphilis, and gonorrhoea. Erythromycin (also known as ilotycin) is produced from a strain of the actinomycete bacterium Saccaropolyspora erythraea (formerly known as Streptomyces erythraeus). Magnification: x50 when shortest axis printed at 25 millimetres.