Antibiotic resistance of Streptococcus pneumoniae colonizing the nasopharynx of HIV-exposed Tanzanian infants

P. Bles, Q. de Mast, C.E. van der Gaast - de Jongh, G.D. Kinabo, G. Kibiki, A. van de Ven and M. I. de Jonge
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To determine antibiotic susceptibility of colonizing pneumococcal serotypes in HIV-exposed infants before the introduction of the 13-valent Pneumococcal Conjugate Vaccine (PCV13), because HIV-exposed infants are at increased risk for invasive pneumococcal infections.


Antibiotic susceptibility of 104 pneumococcal isolates, cultured from the nasopharynx from Tanzanian HIV-exposed infants, was determined using the disk diffusion method and the E-test according to EUCAST version 4.0 (2014) criteria.


69.2% of isolates were intermediately susceptible for benzyl penicillin (MIC 0.06 - 2 mg L-1); no high level resistance was found. All isolates but one were susceptible to ampicillin. Regarding non-beta-lactam antibiotics, 19.2% of isolates were resistant to doxycycline, 3.8% to erythromycin and 97.1% to trimethoprim/sulfamethoxazole. 15.4% of isolates were resistant to three antibiotic classes or more. There were no differences in antibiotic susceptibility between vaccine and non-vaccine serotypes. Reduced susceptibility of colonizing pneumococcal isolates for commonly used antibiotics is common in HIV-exposed Tanzanian infants.


High dose penicillin and ampicillin remain appropriate first choices for non-meningeal pneumococcal infections in this group.