Geisler et al1 have typed strains of Chlamydia trachomatis from 102 individuals in Alabama who tested positive by culture and/or PCR at baseline, and again when they returned for treatment up to 60 days later, by sequencing the ompA gene. Ninety per cent of the subjects were female and 88% were African American. The most commonly identified genotype was E (28%), as has been found in other studies, followed by D/Da (23%) and J/Ja (19%). Subjects infected with genotype J/Ja were significantly more likely to be culture negative, suggesting that they might have a lower bacterial load than found with other genotypes and …