Genes encoding AmpC cephalosporinases (AmpC) may be chromosomal or plasmid-based in origin, whereas genes encoding extended-spectrum [beta]-lactamases (ESBLs) are most often carried on mobile genetic elements, such as plasmids or transposons, and cause resistance to all [beta]-lactams except carbapenems and cephamycins
Generally they confer resistance to 1st, 2nd and 3rd generation cephalosporins along with monobactams, but are sensitive to cephamycins
and carbapenems (12).
Additionally, M100-S24 includes a definition of susceptible-dose dependent(SDD) with educational information explaining the introduction of SDD interpretive criteria; an example and explanation for antimicrobial agents having only susceptible interpretive criteria; information for reporting first- and second-generation cephalosporins and cephamycins
for Salmonella spp.
Phylogenetic origin and virulence genotype in relation to resistance to fluoroquinolones and/or extendedspectrum cephalosporins and cephamycins
among Escherichia coli isolates from animals and humans.
Extended spectrum [beta]-lactamases (ESBLs) are plasmid mediated enzymes inactivating [beta]-lactam antibiotics containing oxyimino group such as oxyiminocephalosporins and oxyimino-monobactam, except cephamycins
and carbapenems (1).
Pharmaceutical Medicaments containing cephamycins
Products and certain other antibiotics; certain medicaments containing hormones; certain medicaments containing alkaloids; etc.
Resistance has been reported for aminopenicillins, first- and second-generation cephalosporins, cephamycins
, most aminoglycosides, and tetracyclines, among others.
Resistance has been reported for aminopenicillins, cephamycins
, first- and second-generation cephalosporins, most aminoglycosides, and tetracyclines, among others.
Beta-lactams are a broad class of antibiotics that includes all penicillin derivatives, cephalosporins, cephamycins
ESBL-producing Enterobacteriaceae (ESBL-E) are usually resistant to most b-lactams except cephamycins
have a broader substrate of hydrolysis ranging to penicillins, cephalosporins, cephamycins
, oxacephamycins, and carbapenems, but not monobactams.
ESBLs are [beta]-1actamases capable of conferring bacterial resistance to the penicillins, first-, second-, and third-generation cephalosporins, and aztreonam (but not the cephamycins
or carbapenems) by hydrolysis of these antibiotics, and are inhibited by [beta]-1actamase inhibitors such as clavulanic acid.