Incidence of macrolide–lincosamide–streptogramin B resistance amongst beta-haemolytic streptococci in The Gambia

In West Africa, penicillin, macrolide and lincosamide resistance among beta-haemolytic streptococci (BHS) isolates has rarely been described. However, such data are critical to detect and track the emergence of antibiotic resistance. Beta-haemolytic streptococci were cultured from clinical specimens from patients attending the clinic at the Medical Research Council Unit The Gambia (n = 217) and kept at −70 °C. Of these, 186 were revived and tested for penicillin susceptibility by disc diffusion and E-test methods, and the D-test for determination of constitutive and inducible macrolide–lincosamide (MLS B ) resistance phenotypes. The majority of BHS isolates from infections were group A streptococci (GAS) (126/186, 67.7%). Of these, 16% were from invasive disease (30/186). Other BHS isolated included lancefield groups B (19, 10.2%); C (9/186, 4.8%), D (3/186, 1.6%), F (5/186, 2.7%), G (16/186, 8.6%) and non-typeable (8/186, 4.3%). Prevalence of BHS isolated from blood cultures ranges from 0% (2005) to 0.5% (2010). Most (85, 45.7%) of the isolates were from wound infections. Of the 186 BHS isolates, none was resistant to penicillin and 14 (6.1%) were resistant to erythromycin. Of these, 8 (4.3%) demonstrated constitutive MLS B resistance, and 5 (2.7%) were inducible MLS B resistant. All the inducible MLS B isolates were GAS, and majority of the constitutive MLS B isolates (6/8, 75.0%) were non-GAS. Beta-haemolytic streptococci, predominantly GAS are associated with a wide range of infections in The Gambia. It is reassuring that macrolide and lincosamide resistance is relatively low. However, monitoring of MLS B resistance is necessary with the global spread of resistant BHS strains.