Survival and surface adherence ability of bacterial pathogens in oral liquid pharmaceuticals and their containers

RESUMO

The survival and surface adherence ability of Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa in nutrient broth and in five oral liquid pharmaceuticals (nivaquine syrup, cough mixture, paracetamol elixir, cotrimoxazole and vitamin C) were investigated The bacteria grew more in nutrient broth than in the pharmaceuticals (p < 0. 001) and the recovery of stressed cells was enhanced when 3 Tween 80 was used as the recovery medium as against the use of normal saline (p < 0.01). The Gram-negative bacteria were more adapted to the pharmaceuticals than their Gram-positive counterparts. Klebsiella pneumoniae and Ps. aeruginosa were recovered in large numbers from nivaquine and cotrimoxazole suspensions that did not support the growth of the other bacteria. The effect of bacterial growth on the physico-chemical properties of the pharmaceuticals was also evaluated The properties were not altered significantly except for pH shifts of 0.3 to 1.1 caused by E. coli and S. aureus in paracetamol and vitamin C. Adherence capability was found to correlate with the survival ability of the bacteria. Populations on coupons were significantly higher when nutrient broth was used as the suspending medium compared with any of the pharmaceuticals (p < 0.01). Rubber and plastic coupons were significantly more accessible to the bacteria than glass coupon as revealed by the high population of bacteria recovered from their surfaces