Pattern of infection and antibiotic activity among Streptococcus agalactiae isolates from adults in Mashhad, Iran

Area of Science:

• Microbiology
• Infectious Diseases
• Public Health

Background:

• Group B Streptococcus (GBS) is a significant cause of sexually transmitted diseases due to its proliferation in genital tracts.
• Penicillin is the primary treatment for GBS infections, with Erythromycin and Clindamycin as alternatives for penicillin-allergic patients.
• Increasing reports of GBS resistance to alternative antibiotics necessitate further investigation.

Purpose of the Study:

• To determine the prevalence of GBS in genital tract samples.
• To assess the antibiotic resistance patterns of GBS isolates.
• To evaluate the antibiotic resistance of GBS against commonly used drugs.

Main Methods:

• Over 2400 urine and genital discharge samples were analyzed using the modified Christie Atkins Munch-Petersen (CAMP) test.
• Antibiotic susceptibility was tested using double disk diffusion assays for Bacitracin, Trimethoprim, and Sulfamethoxazole.
• Resistant isolates underwent E-test to determine minimum inhibitory concentrations (MICs).

Main Results:

• GBS was detected in 23 vaginal, 10 urethral, 27 urine, and 6 prostatic samples.
• Common co-infecting microorganisms included Enterococci (90%), Staphylococcus saprophyticus (25%), and Candida albicans (6%).
• Penicillin resistance was observed in 18 cases, with a minimum inhibitory concentration (MIC) of 1.5 mg/ml.

Conclusions:

• The overall GBS carrier rate was 20.65% (12.4% in women, 8.24% in men).
• A significant finding was the high-level resistance of GBS to Erythromycin and Clindamycin.
• These resistance patterns highlight potential challenges in treating GBS infections, especially in penicillin-allergic individuals.