Transmissible drug resistance in certain enteric bacilli isolated in Tehran

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Urinary tract infections (UTIs) are commonly caused by gram-negative enteric bacilli.
• Antimicrobial resistance in these bacteria poses a significant public health challenge.
• R factors, or resistance plasmids, are a major mechanism for the spread of antimicrobial resistance.

Purpose of the Study:

• To investigate the prevalence of antimicrobial resistance in gram-negative enteric bacilli from UTIs and normal fecal flora.
• To determine the presence and frequency of transmissible R factors in resistant bacterial isolates.
• To compare drug resistance patterns between clinical and healthy isolates of Escherichia coli.

Main Methods:

• Collected 284 isolates of gram-negative enteric bacilli from UTI patients and healthy individuals.
• Tested isolates for resistance to various antimicrobial agents.
• Assessed the presence of transmissible R factors in resistant strains using bacterial conjugation experiments.

Main Results:

• Klebsiella pneumoniae and Proteus species showed the highest antimicrobial resistance frequencies.
• Clinical Escherichia coli isolates exhibited significantly higher drug resistance than those from healthy individuals.
• Transmissible R factors were detected in 43% of resistant E. coli from UTIs and 21-26% from healthy individuals. R factor transfer rates were 26% for K. pneumoniae and 28% for Proteus.

Conclusions:

• Gram-negative enteric bacilli, particularly from UTIs, demonstrate substantial antimicrobial resistance.
• Transmissible R factors are prevalent in resistant strains of E. coli, K. pneumoniae, and Proteus, facilitating resistance spread.
• The high incidence of resistance and R factors highlights the need for strategies to combat antimicrobial resistance in clinical settings.