A young male comes with penicillin allergy and meningitis treatment?
a. Macrolides (e.g. erythromycin) are macrocyclic antibiotics i.e. antibiotics with large rings. Ketolide are used against macrolide resistant bacteria (e.g. telithromycin). Spectrum of ketolide is larger than that of macrolide group and have better activity against respiratory infections.
b. Macrolides block protein synthesis by inhibiting the initial step in chain elongation.
c. Erythromycin is well absorbed orally and undergoes enterohepatic circulation. It is potent enzyme inhibitor and should not be given with lovastatin (myopathy can occur).
d. Macrolides do not enter blood brain barrier so will not be a good choice in meningitis. Vancomycin, a glycopeptides antibiotic too does not enter BBB and therefore, answer is chloramphenicol.
e. Chloramphenicol is active against gram positive, negative and most of anaerobic bacteriA. Oily chloramphenicol is the drug of choice for treatment of meningitis in low income countries.
f. It has good activity against, staphylococcus, H. Influenza, Neisseria Meningitides. Importantly, most strains of MRSA are also sensitive to chloramphenicol. It is also a good option when causative organism is not known or mixed infections.
g. Importantly, drug of choice for empirical treatment of meningitis now a days is ceftriaxone (BG Katzung’ 10th Edition, 2010).
( Rememeber : Chloramphenicol crosses BBB ,but rarely used because of Idiosyncratic respone/ Irreversible aplastic anemia.)