Bloodstream Infections by AmpC-Producing Enterobacterales: Risk Factors and Therapeutic Outcome.

Area of Science:

• Clinical microbiology
• Infectious diseases
• Antimicrobial resistance

Background:

• Bloodstream infections (BSIs) caused by AmpC-producing Enterobacterales present a significant clinical challenge.
• Effective treatment is crucial to prevent severe outcomes.

Purpose of the Study:

• To investigate the association between patient comorbidities, surgical history, and AmpC-producing Enterobacterales resistance determinants in BSIs.
• To determine antibiotic resistance patterns and treatment outcomes.

Main Methods:

• Retrospective analysis of patient data, focusing on comorbidities and surgical history.
• Phenotypic and genotypic characterization of AmpC-producing Enterobacterales isolates.
• Assessment of antibiotic resistance profiles, including AmpC hyperproduction, ESBL, and carbapenemase production.
• Evaluation of therapy outcomes and mortality rates.

Main Results:

• No significant difference in comorbidities or prior surgeries was found between resistant and susceptible AmpC-producing Enterobacterales isolates.
• Overall, 34.52% of isolates exhibited resistance (AmpC hyperproduction, ESBL, or carbapenemase).
• High rates of resistance to expanded-spectrum cephalosporins were noted in *Providencia* spp. and *K. aerogenes*. Carbapenemase production was most frequent in *Providencia* spp.

Conclusions:

• Comorbidities and surgical history do not appear to be associated with specific resistance mechanisms in AmpC-producing Enterobacterales BSIs.
• A substantial proportion of AmpC-producing Enterobacterales isolates demonstrate multidrug resistance, posing a therapeutic challenge.
• The increasing antibiotic resistance necessitates the development of novel treatment strategies.