B-lactams act by preventing formation of pentaglycine bridge in peptidoglycan

Examples: monobactam, penicillin, cephalosporin/cephamycin, B-lactamase inhibitor, and carbapenem

Spectrum: gram positive aerobic organisms that don't make B-lactamase like Streptococcos spp

some gram neg organisms: Neisseria meningitidis 

some gram pos and gram neg anaerobes: actinomyces spp, fusobacterium spp

same as PCN G (gram pos orgs which do not make b- lactamase, strep spp, some gram neg: Neiss menin), some gram pos and gram neg anaerobes - actinomycets and fusobacterium

AND some more gram neg: 

Haemophilus influenzae (~65%) and E. coli (~50%) which are not susceptible to PCN G

methicillin - susceptible Staph spp which DO make B-lactamase

S. Aureus (MSSA)

S. epidermidis (MSSE)

NOT MRSA, or MRSE

• gram pos aeorobic organisms that don't make b- lactmase, like strep
• some gram neg orgs - neiss meningitis
• some gram pos and gram neg anaerobes - actinomyces and fusobacterium
• many more gram neg orgs: H. influenzae, enterobacteriaceae (klebsiella), Pseudomonas aeruuoginosa, Neisseria gonnorhoeae
• not active vs. staph spp

• amox/clavulanate and ampicillin/sulbact not active vs pseudomonas  but active vs staph (NOT MRSA or MRSE)
• tic/clav and pip/tazo are active against pseudomonas and against staph but MRSA or MRSE
• active against aerobic gram neg rods
• aerobic gram pos cocci
• anaerobes

• gram pos aerobic orgs, strep
• gram neg - neiss menin
• gram pos and neg anaerobes; actinomycetes and fusobacterium
• Methicilin-suscept staph spp: S. aureus and S. epidermidis
• some gram neg: E.coli, K. pneumoniae, and P. mirablilis
• NOT haemophilus spp
• NOT enterococcus spp
• NOT MRSA
• and ok vs anaerobes

gram pos bacteria

gram neg bacteria: most enterobacteria, haemophilus, and not pseudomonas

anti-pseudomonal cephalosporin

the pyridine group increases activity vs pseudomonas aeurginosa by increasing poirn channel penetration

poor gram pos activity

gram neg activity: MOST enterobacteriaceae, most pseudomonas, and haemophilus

- more broad spectrum cephalosporin than ceftazidime because good gram positive activity

gram neg bacteria: most enterobacteriaceae, most pseudomonas, and haemophilus

use in treating nosocomial gram neg bacillary infection (pneumonia due to resis. org) 

serious pseudomonas infection

they have a trans hydroxylethyl side chain attached to B-lactam ring for B-lactamase stability

avidly binds to high MW PBPs (avidly) esp PBP2

very broad spectrum: enterobacteriace, pseudomonas spp, gram pos cocci, anaerobes

has benzoate moiety: changes overall molecular charge, making it more bound to protein and thus increasing half life

long half-life, so can administer once daily

very broad spectrum: enterobacteriaceae, NOT pseudomonas spp, gram + cocci but not enterococcus spp, and anaerobes

very broad spectrum: enterobacteriaceae, pseudomonas spp - more active than imi and meropenem

greater activity vs non fermenters

gram pos cocci

anaerobes

During life-threatening infections

nosocomial gram-bacillary infections: pneumonia due to resis org

polymicrobial infections, especially when resistant organisms present, like in necrotizing fasciitis, potentially

monobactam

monocyclic B-lactam ring

binds to PBP 3 in GNRods

the propylcarboyl group stabilizes it in P. aeruginosa

no activity vs gram pos, and anaerobes

no cross allergenicity to B-lactams

spectrum: aerobic gram neg bacilli including pseudomonas aeruginosa