klebsiella oxytoca and k1 enzyme (indole positive) chromosomal r/ ampicillin mutational...
Post on 20-Dec-2015
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Klebsiella oxytocaand K1 enzyme
(indole positive)
• Chromosomal
R/ ampicillin • Mutational hyperproduction
R/ cephalosporins• Less susceptible to clavulanic acid than ESBL
No key holeKey hole not obvious
A Klebsiella oxytoca with basal K1 -lactamase resistant to ampicillin and susceptible to Augmentin, cephalexin and cefotaxime.
A hyperproducer Klebsiella oxytoca with a high level of mutational K1 -lactamase shows resistance to Augmentin, cephalexin and cefotaxime.
Another hyperproducer Klebsiella oxytoca with a high level of mutational K1 -lactamase. Note the tiny "keyhole" between cefotaxime (CTX 5) and Augmentin (AMC 60) and the small inhibitory zone around cephalexin (CL100). The tiny "keyhole“ is a “bonus” as most strains with high K1 activity simply show resistance to Augmentin, cephalexin and cefotaxime.
A hyperproducer Klebsiella oxytoca with a low level of mutational K1 -lactamase. Note the slight synergy between Augmentin (AMC 60) and the cephalosporin discs cephalexin (CL100) and cefotaxime (CTX 5).
A Klebsiella oxytoca with an ESBL. It’s likely that the isolate only has basal K1 -lactamase (large zone around AMC 60).
Reporting
Klebsiella oxytoca hyperproducer of K1
Not ESBL (plasmid mediated)
As per Table 4
R/ ampicillin, cephalexin, cefotaxime…..
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