Antibiotic Treatment of Infections Caused by AmpC-Producing Enterobacterales

• Main Authors: Gianpiero Tebano (Author), Irene Zaghi (Author), Monica Cricca (Author), Francesco Cristini (Author)
• Format: Book
• Published: MDPI AG, 2024-09-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

AmpC enzymes are a class of beta-lactamases produced by Gram-negative bacteria, including several Enterobacterales. When produced in sufficient amounts, AmpCs can hydrolyze third-generation cephalosporins (3GCs) and piperacillin/tazobactam, causing resistance. In Enterobacterales, the AmpC gene can be chromosomal- or plasmid-encoded. Some species, particularly <i>Enterobacter cloacae</i> complex, <i>Klebsiella aerogenes</i>, and <i>Citrobacter freundii</i>, harbor an inducible chromosomal AmpC gene. The expression of this gene can be derepressed during treatment with a beta-lactam, leading to AmpC overproduction and the consequent emergence of resistance to 3GCs and piperacillin/tazobactam during treatment. Because of this phenomenon, the use of carbapenems or cefepime is considered a safer option when treating these pathogens. However, many areas of uncertainty persist, including the risk of derepression related to each beta-lactam; the role of piperacillin/tazobactam compared to cefepime; the best option for severe or difficult-to-treat cases, such as high-inoculum infections (e.g., ventilator-associated pneumonia and undrainable abscesses); the role of de-escalation once clinical stability is obtained; and the best treatment for species with a lower risk of derepression during treatment (e.g., <i>Serratia marcescens</i> and <i>Morganella morganii</i>). The aim of this review is to collate the most relevant information about the microbiological properties of and therapeutic approach to AmpC-producing Enterobacterales in order to inform daily clinical practice.

Item Description

10.3390/pharmacy12050142
2226-4787