Multi-drug resistant non-typhi salmonellae in Kenya

Area of Science:

• Microbiology
• Molecular Biology
• Infectious Diseases

Background:

• Non-typhi Salmonellae (NTS) are an important cause of morbidity, especially in individuals with HIV-1.
• Multi-drug resistance (MDR) in bacterial pathogens poses a significant global health threat.
• Understanding the mechanisms of MDR transmission in NTS is crucial for effective treatment and control.

Purpose of the Study:

• To characterize self-transmissible multi-drug resistance plasmids in non-typhi Salmonellae (NTS) isolated from blood.
• To investigate the prevalence of antibiotic resistance and beta-lactamase production in NTS strains.
• To determine the genetic relatedness of resistance plasmids within NTS populations.

Main Methods:

• Plasmid characterization using restriction digest patterns and incompatibility grouping.
• Evaluation of resistance to ampicillin and other beta-lactams via iso-electric focusing and disc inactivation.
• Analysis of NTS isolates from blood, including phage typing and antibiotic susceptibility testing.

Main Results:

• Over 47% of NTS isolates exhibited resistance to three or more common antibiotics.
• Self-transferable resistance plasmids (approx. 100 kb) were predominantly of incompatibility group incFIIA.
• More than half of strains produced TEM-1 and OXA-1 beta-lactamases; plasmid restriction patterns showed diversity.

Conclusions:

• A high prevalence of transmissible multi-drug resistance was observed among NTS.
• NTS carrying MDR plasmids are a significant concern for patients, particularly those who are HIV-1 seropositive.
• The findings highlight the need for continued surveillance and control strategies against MDR NTS.