Antibiotic Treatment of Infections Caused by AmpC-Producing Enterobacterales

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• AmpC enzymes are beta-lactamases produced by Gram-negative bacteria, notably Enterobacterales.
• Overproduction of AmpC leads to resistance against third-generation cephalosporins (3GCs) and piperacillin/tazobactam.
• AmpC genes can be chromosomal or plasmid-encoded, with some species exhibiting inducible chromosomal AmpC.

Purpose of the Study:

• To review the microbiological properties of AmpC-producing Enterobacterales.
• To outline therapeutic approaches for AmpC-producing Enterobacterales.
• To provide guidance for daily clinical practice regarding these resistant pathogens.

Main Methods:

• Literature review of microbiological properties of AmpC-producing Enterobacterales.
• Analysis of therapeutic strategies for AmpC-producing Enterobacterales.
• Synthesis of current evidence to inform clinical decision-making.

Main Results:

• Inducible chromosomal AmpC in species like *Enterobacter cloacae* can lead to resistance during beta-lactam treatment.
• Carbapenems or cefepime are often preferred for infections caused by high-risk AmpC-producing Enterobacterales.
• Uncertainties remain regarding specific beta-lactam risks, piperacillin/tazobactam vs. cefepime roles, and optimal treatment for severe infections or lower-risk species.

Conclusions:

• AmpC-producing Enterobacterales pose a significant challenge due to inducible resistance mechanisms.
• Understanding AmpC gene location and expression is crucial for effective antimicrobial selection.
• Further research is needed to address persistent clinical uncertainties in managing these infections.