| ObjectiveCounting the viable of Acinetobacter baumannii (A. baumannii) after culture, to investigate the effects of Peracetic acid (PAA) in sterilization, clarified the resistance of A. baumannii and the mechanism of PAA in disinfection and made prevention and controll strategies in A. baumannii infection.Materials and methodsMaking suspension of the laboratory storage A. baumannii , measuring the concentration of bacteria with turbidimetry, then diluted to 1×10~8 cfu/ml-5×10~8 cfu/ml. Using binary packaging PAA solution, then mixing A and B with 10:8(v/v) to confine with 24,48 and 72h.After which, measured the concentration with iodimetry, with sterile preparation hard water to preparate PAA dilute solution. Insight with the disinfection of technical specifications for identification of neutralizer, chose 3g /L thiosulfate and 10g/L Tween-80 as a neutralizer. Added 0.5ml A. baumannii suspension to the disinfected test tube, then added organic interference 0.5ml(0.3% bovine serum albumin and 3%bovine serum albumin), bathed at 20±1℃for 5 min, then added 4.0 ml PAA to the tube with sterile draw straws mixed immediately. At the scheduled time, added 0.5ml above mixture with the 4.5ml sterilization of neutralizer, mixed for 10min.Then added 1.0ml sample to the sterile dish (every sample for 2 dish). Poured 15ml pancreas peptone soy agar (TSA) cooling to 10-45℃to the sterile dish. After solidified, placed it in 37℃incubators for 48 hours, calculated colonies. Test was divided into three groups for PAA concentration(0.005% (50mg/l) ,0.01% (100mg/l), 0.02%(200mg/l)) and five groups for time (1min,3min,5min, 15min,30min). At the same time setting up the control group: using diluted liquid disinfectant for parallel testing, as a positive control, which was the original concentration of bacilli, then calculated the initial concentration. Tests were repeated three times, each group calculated the concentration of viable (cfu /ml).Results1,PAA content: after 24,48 and 72h, contents were 182g/l,194g/l,188g/l respectively.2,Neutralizer qualification test: PAA by 0.02% and 3% bovine serum albumin, neutralizer 3g/L sodium thiosulfate and 10g/L Tween-80, Group 1 with no bacteria, Group 2 with 158cfu/ml bacteria, Group 3 with 56625000cfu/ml bacteria, Group 4 with 57292000cfu/ml bacteria, Group 5 with 60080000cfu/ml bacteria, Group 6 with no bacteria and in Group 3, 4, 5 the colonies of the group error rate is 2.4%.3,Group comparison in 3% bovine serum albumin as an organic interference test: the PAA sterilization effects in the three group were significantly different (P<0.01). The effect of 0.01% and 0.02% PAA group is more potential then 0.005% group (P<0.01).4,Group comparison in 0.3% bovine serum albumin as an organic interference test: the PAA sterilization effects in the three group were significantly different (P<0.01). There was no significant difference between the 0.005% and 0.01% PAA group in the bactericidal effect(P>0.05). The effect of PAA 0.02% group is more potential than the PAA 0.01% and 0.005% group(P<0.01).5,3% bovine serum albumin and 0.3% bovine serum albumin organic interference under the effects of sterilization: 0.005% peracetic acid effects of sterilization:3% bovine serum albumin was significantly lower than 0.3% bovine serum albumin(P<0.01); 0.01% peracetic acid effects of sterilization: 3% bovine serum albumin group and 0.3% bovine serum albumin was no significant difference (P>0.05); 0.02% peracetic acid effects of sterilization: 3% bovine serum albumin group and 0.3% bovine serum albumin was no significant difference(P>0.05).ConclusionIn the range of 0.005%-0.02%PAA,the higher content PAA, the effects of sterilization is relative good.For the disinfection goods and equipment in the hospital, choosing 0.01% PAA for 5 min, or 0.02% PAA for 1 min. To achieve the status of sterilization, choosing 0.01% PAA for 10 min, or 0.02% PAA for 5min. Organic interference (bovine serum albumin ) affect 0.005%PAA effects of sterilization,but not affect 0.01% and 0.02% PAA effects of sterilization .The research is benefit to achieve the guidance of clinical work and reduce infection rates, shortened the average day in hospital of patients and reduce the cost of evaluation and reduce drug resistant strains of Acinetobacter in the spread of the patients, prevention and control of epidemic outbreaks.
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