Non-typhoid Salmonella spp. resistant to cefotaxime

Area of Science:

• Microbiology
• Molecular Biology
• Antimicrobial Resistance

Background:

• Salmonella spp. are significant foodborne pathogens.
• Antimicrobial resistance in Salmonella poses a global health threat.
• Beta-lactamase enzymes are a primary mechanism of resistance to beta-lactam antibiotics.

Purpose of the Study:

• To investigate the presence and types of beta-lactamases in cefotaxime-resistant Salmonella serovars from Argentina.
• To identify specific beta-lactamase enzymes conferring resistance.

Main Methods:

• Detection of beta-lactamases by analyzing enzyme hydrolysis of ampicillin and ceftriaxone.
• Isoelectric focusing (pI) to characterize the detected beta-lactamases.

Main Results:

• Two distinct beta-lactamases with isoelectric points (pIs) of 5.4 and 8.1 were identified.
• The beta-lactamase with pI 5.4 was identified as TEM-1.
• An unidentified extended-spectrum beta-lactamase was detected in the resistant Salmonella strains.

Conclusions:

• The spread of TEM-1 and an extended-spectrum beta-lactamase is evident in Salmonella serovars in Argentina.
• These findings highlight the growing challenge of antimicrobial resistance in Salmonella.
• Further characterization of the unidentified extended-spectrum beta-lactamase is warranted.