Gonococcal antibiotic resistance in Los Angeles

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Neisseria gonorrhoeae is a major cause of sexually transmitted infections.
• Antibiotic resistance in gonococci has been a growing concern since the mid-20th century.
• Understanding historical susceptibility patterns is crucial for effective treatment strategies.

Purpose of the Study:

• To assess the antibiotic susceptibility of gonococcal isolates from Los Angeles in 1972.
• To evaluate resistance patterns to penicillin, tetracycline, and spectinomycin, among other antibiotics.
• To compare different antimicrobial agents against Neisseria gonorrhoeae.

Main Methods:

• Antibiotic susceptibility testing of 135 gonococcal isolates.
• Evaluation of resistance to penicillin, ampicillin, carbenicillin, tetracycline, minocycline, doxycycline, and spectinomycin.
• Comparison of agar dilution and disc diffusion methods for antibiotic sensitivity assessment.

Main Results:

• Only 12% of isolates were sensitive to penicillin (0.05 µg/ml); 35% required ≥0.5 µg/ml.
• 19% of isolates required ≥1.0 µg/ml of tetracycline.
• 49% were sensitive to spectinomycin (2.0 µg/ml), but 37% required ≥8.0 µg/ml.
• Nine of eleven tetracycline-resistant isolates were also resistant to penicillin and spectinomycin.
• Agar dilution and disc diffusion methods showed good correlation for penicillin but not for tetracycline or spectinomycin.

Conclusions:

• Gonococcal isolates from 1972 exhibited considerable resistance to penicillin and tetracycline.
• Emerging resistance to spectinomycin was also noted.
• The findings highlight the need for ongoing surveillance of Neisseria gonorrhoeae antibiotic susceptibility.