THE EFFECTS OF MEDIUM AND RATE OF FREEZING AN THE SURVIVAL OF CHLAMYDIAS AFTER LYOPHILIZATION

The effects of suspension media and rate of freezing on the survival o f Chlamydia trachomatis LGV(2) and Chlamydia pneumoniae after lyophili zation were assessed. The highest loss in infectious elementary bodies (EBs) occurred during lyophilization. The survival was higher after f reezing at a rate of 1 degrees C min(-1) and lyophilization than that after rapid freezing at -70 degrees C or -196 degrees C. The recovery (+/-5%) was higher when fetal calf serum (FCS) containing glucose, sac charose or lactose were used as lyophilization media than that (0.5-3% ) when yolk-sac, skimmed milk or phosphate buffer containing sucrose, glutamine and 10% FCS (SPG) were used. After lyophilization, the survi val was not affected in the tested range from 10(4) to 5 x 10(6) inclu sion-forming units (ifu) ml(-1) prior to freezing. After storage for 4 months at 4 degrees C, the numbers of ifu of both Chlamydia serovars that were recovered were identical to the numbers of ifu immediately a fter lyophilization. It was concluded that chlamydias can be stored an d transported in lyophilized form. However, a loss of 95% in infectiou s EBs should be taken into account.