Clindamycin Flashcards
Clindamycin is a
lincosamide antibiotic; chlorine-substituted derivative of lincomycin
Clindamycin is bactericidal/bacteriostatic
bacteriostatic
Clindamycin MOA
inhibits protein synthesis by binding reversibly to 50S ribosomal subunits of susceptible bacteria
inhibits peptide formation and interferes with translocations step
binds near site where macrolides bind
Clindamycin spectrum coverage
dark purple: prevotella
light purple: streptococcus, s. pneumoniae, viridans, MSSA, MRSA
dark red: fusobacterium
light red: bacteroides, clostridium
Other: pneumocystic jirovecii, protozoa
Clindamycin resistance mechanisms
mutation of bacterial ribosomal RNA
alterations in 50S ribosomal proteins at receptor site
enzymatic inactivation
modification of 23S ribosomal unit of 50S receptor by methylation of adenine (erm)
inducible resistance occurs during therapy
Macrolide and Lincosamide resistance
methylation of the ribosomal target which leads to cross-resistance to macrolides, lincosamides, and streptogramin B
MLSB phenotype which can be constitutive or inducible
Macrolide and Lincosamide resistance is mediated by
plasmids
Efflux by ERY
msrA (low level)
ribosome alteration (ERY, CLI)
Erm (high level)
Drug inactivation (CLI)
inuA (rare)
D-test positive is when
erythromycin causes clindamycin ring to look like a D
msrA
ERY:
CLI:
E: R
C: S
erm
ERY:
CLI:
E: R
C: S inducible
erm
ERY:
CLI:
E: R
C: R constitutive
both negative
ERY:
CLI:
E: S
C: S