lincomycins

Lincomycins are a class of antibiotics in the lincosamide family. The group includes lincomycin, a natural product produced by Streptomyces lincolnensis, and clindamycin, a semisynthetic derivative with improved oral absorption and tissue penetration. Lincomycins act by binding reversibly to the 50S subunit of the bacterial ribosome, inhibiting peptide bond formation and translocation, which leads to inhibition of protein synthesis. The resulting effect is generally bacteriostatic.

The spectrum of lincomycins is greatest against anaerobic bacteria and Gram-positive cocci, including many Streptococcus species and Staphylococcus aureus. They have poor activity against most Enterobacterales and other Gram-negative aerobes. Clindamycin, in particular, is widely used for intra-abdominal and gynecologic infections, skin and soft tissue infections, and dental infections, with activity against many community-associated Staphylococcus aureus strains, including some MRSA. Lincomycin is used less frequently today due to poorer oral bioavailability and higher toxicity.

Pharmacokinetics vary between the agents. Clindamycin is well absorbed orally and distributes well into tissues and bone. Lincomycin is typically given by injection and has more limited oral use. Both drugs can be effective, but their use is constrained by resistance and adverse effects.

Resistance to lincomycins commonly involves methylation of the 23S rRNA (MLS_B resistance), leading to cross-resistance with macrolides. Other mechanisms include enzymatic inactivation and efflux. Adverse effects include gastrointestinal upset and, notably, Clostridioides difficile–associated diarrhea. Lincomycins are generally avoided in patients with severe hepatic disease or those at high risk for C. difficile infection unless clearly indicated.