Microbiological methods. All the samples were transported to the laboratory within 15 minutes and cultured within an hour of collection. After receipt in the laboratory, the samples were first vortexed for 60 seconds after which, gram stained preparations were performed and studied for the presence of squamous cells, polymorphonuclear cells and the type of microorganism present. The presence of polymorphonuclear cells (PMN) in the aspirated fluid was semi-quantified using techniques published previously (25). Simultaneously, quantitative cultures using the calibrated loop method were performed on common media such as blood agar, chocolate agar and Mckonky's agar using standard techniques (26). Organisms were identified using automated Vitek - 1 system (bioMerieux, France). Microbiological examination for unusual organisms such as Mycoplasma, Chlamydia, Pneumocystis carinii and viruses did not form a part of this study.