Received: 15 February 2018
Accepted: 20 May 2019
First Online: 31 May 2019
Ethics approval and consent to participate
: Ethical approval was sought and granted by the Medical Research Council of Zimbabwe (MRCZ/B/1066). Stored bacterial isolates not linked to patient information were used and informed consent was waived by Medical Research Council of Zimbabwe.
: Not applicable.
: The authors declare that they have no competing interests.