Malaria in pregnancy is associated with low birth-weight [1–3], pre-term delivery  and maternal anaemia  and is therefore an important cause of maternal, perinatal, and neonatal morbidity and mortality in pregnancy and the puerperium in sub-Saharan Africa [6, 7]. The World Health Organization recommends intermittent preventive treatment of malaria in pregnancy with sulphadoxine-pyrimethamine (SP-IPTp) in order to reduce adverse health outcomes for pregnant women and their offspring [8, 9]. Curative doses of SP are administered during routine antenatal visits at least twice after the first trimester in HIV negative and at least three times in HIV positive women. Due to rising drug resistance of Plasmodium falciparum against SP, potential alternative anti-malarial drugs have been proposed for future use as IPTp . These compounds include amodiaquine, azithromycin, mefloquine, and combinations of these drugs with artemisinin derivatives or chloroquine [11, 12].
Bacterial infections including sexually transmitted diseases, urinary tract infections, and group B streptococcal carriage are causes for considerable morbidity and mortality in pregnant women and the unborn child. In sub-Saharan Africa adequate diagnosis and treatment of these infections are often lacking. SP belongs to the class of anti-folates exerting considerable anti-microbial activity besides its anti-malarial activity. Anti-folate antibiotics show clinically important activity against Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli, and other pathogenic bacteria and are, therefore, used on a large scale for the treatment of urinary tract infections, skin and soft tissue infections, and in other indications [13, 14]. Whereas mefloquine use is currently restricted to treating falciparum malaria, azithromycin is in use for the treatment of a variety of bacterial infections including respiratory tract infections and sexually transmitted diseases and it is under investigation for combination therapy of falciparum malaria [15, 16].
IPTp with a drug exerting anti-bacterial activity may, therefore, offer a significant additional public health benefit by providing treatment for undetected or previously untreated bacterial infections in pregnant women. Conversely, widespread use of antibiotics may increase the risk for the development of drug resistance leading to future difficulties in the clinical management of bacterial infections.
This study aimed to assess the anti-bacterial activity of SP, mefloquine and azithromycin - the most promising candidate drugs for the replacement of SP for IPTp  - against common Gram-positive and Gram-negative bacteria in vitro.