Clindamycin

Some Clinical Uses of Macrolides) except that clindamycin is

• Effective for infections due to anaerobes (except not reliably active against Bacteroides species, including Bacteroides fragilis, because of resistance), most community-acquired methicillin-resistant Staphylococcus aureus, and macrolide-resistant, clindamycin-susceptible Streptococcus pneumoniae

• Not reliably active against mycoplasmas, chlamydiae, Chlamydophila species, and legionellae

Aerobic gram-negative bacilli and enterococci are resistant.

clindamycin resistance has emerged among these organisms, particularly gram-negative anaerobes such as B. fragilis. Because these infections often also involve aerobic gram-negative bacilli, additional antibiotics are also used. Clindamycin is part of combination therapy for the following:

• With penicillin for infections caused by toxigenic streptococci (because clindamycin decreases the bacteria’s toxin production)

• cerebral toxoplasmosis

• babesiosis or falciparum malaria

• Pneumocystis jirovecii pneumonia

Clindamycin can be used for infections (eg, skin and soft-tissue infections) in communities where community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is common; whether clindamycin is useful depends on local resistance patterns.

clindamycin- and erythromycin-susceptible strains. However, some CA-MRSA strains are clindamycin-susceptible and erythromycinclindamycin-susceptible CA-MRSA is resistant to erythromycin because of the efflux mechanism, patients can be expected to respond to clindamycin. However, if the strain is erythromycin-resistant because of modification of the ribosomal target, patients may not respond clinically to clindamycin because certain mutants can emerge during clindamycin therapy; these mutants are resistant to clindamycin and erythromycin because of constitutive modification of the ribosomal target. (Constitutive means that resistance is always present regardless of whether an inducer, such as erythromycin, is present.)

erythromycin disk on an agar plate streaked with a standard inoculum of the CA-MRSA strain in question. Zone of growth inhibition (shaped like the letter “D”) around the clindamycin disk, with a flattened zone nearest the erythromycin disk indicates inducible ribosomal resistance. Patients who have moderate to severe infection with an inducible ribosomal-resistant CA-MRSA strain and a positive D test should not be treated with clindamycin.

Clindamycin cannot be used for central nervous system infections (other than cerebral toxoplasmosis) because penetration into the brain and cerebrospinal fluid is poor.

acne.

clindamycin given during the second and third trimesters has not been associated with an increased frequency of birth defects. If medically indicated, clindamycin can be used during pregnancy.

Clindamycin enters breast milk. Use during breastfeeding is not recommended.

• Clostridioides (formerly Clostridium) difficile–associated diarrhea (pseudomembranous colitis)

Clindamycin is more strongly associated with C. difficile colitis than any other antibiotic and has a boxed warning for this adverse effect. C. difficile–associated diarrhea is about 20 times more likely to occur after clindamycin exposure than after no antibiotic exposure (1), whereas other antibiotics, including fluoroquinolones and cephalosporins, have about 5 to 10 times greater odds of C. difficile compared to no antibiotics (2).

Hypersensitivity reactions may occur. The most commonly reported adverse effect is mild to moderate maculopapular rash, but severe skin reactions, including toxic epidermal necrolysis, have also been reported.

If not swallowed with water, clindamycin may cause esophagitis.