Problem Gram Negative Organisms

These include the following two groups:

1. ESBL (Extended-spectrum beta-lactamases) producers:

• Klebsiella
• E.coli
• Enterobacter
• Serratia

1. Pseudomonas

They are hard to treat due to drug-resistance mechanisms

Management

• Cephalosporins and beta-lactam inhibitor combinations fail and the only effective treatment is with carbapenems.

Note that there is a rising incidence of carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Klebsiella.

Penicillin allergy:

• Cross-reactivity between penicillins and carbapenems has been reported between 9.2-11%, but may be lower.
• Carbapenems are only contraindicated when patients have had an anaphylactic reaction to penicillin.