[Experimental studies on superinfection of acute simple urinary tract infection]

Experimental acute simple urinary tract infections were induced in female rats to determine whether low-virulent bacteria can reside in the simple urinary tract, whether minor flora can co-exist with major flora, and whether the bacterial population changes when antibiotics, to which major flora is sensitive and minor flora is resistant, is administered. "Enterococcus faecalis (E. faecalis) and Pseudomonas aeruginosa (P. aeruginosa) were instilled into the bladder transurethrally. Most rats had more than 1 x 10(4) CFU/ml of E. faecalis and P. aeruginosa two and four days after inoculation. Rats were divided into three groups. Mitomycin C injection group, acetic acid bladder instillation group, hydrocortisone injection group. E. faecalis (1 x 10(7) CFS/ml) and P. aeruginosa (1 x 10(4) CFS/ml) were instilled into the bladder. Bacterial count of E. faecalis was over 1,000 times that of P. aeruginosa in 14 rats two days after inoculation and in two rats six days after inoculation. Ampicillin (ABPC) was administered once a day for four days from two to five days after inoculation under the same condition. Bacterial count of E. faecalis was over 1,000 times that of P. aeruginosa in 26 rats two days after inoculation. The bacterial population changed in seven of the 26 rats after administration of ABPC, and in three of the 12 untreated rats.