血清不耐热物质对噬菌体PL39杀灭铜绿假单胞菌的影响

Analysis of the influence of heat-labile serum components on phage PL39 killing different Pseudomonas aeruginosa strains

目的观察人血清和鼠血清中不耐热物质对噬菌体PL39杀灭不同克隆铜绿假单胞菌的影响。方法采用双层平板法筛选PL39敏感宿主菌;根据ERIC-PCR图谱分析敏感宿主菌的遗传差异性。分别添加新鲜及热灭活人血清和鼠血清,观察其对PL39杀灭不同敏感宿的影响。结果筛选到9株PL39敏感宿主菌,其中2株菌ERIC指纹图谱无明显不同,其他菌株的指纹图谱明显不同。9株菌均能完全抵抗人血清和鼠血清的溶菌作用;噬菌体PL39在两种血清中均能保持恒定的成斑活性,但在人血清中对9株宿主菌的杀灭作用均被抑制;在小鼠血清中,PL39对L39菌有一定杀灭作用,对其他宿主菌无杀灭作用;两种血清热灭活(56℃,30min)后对PL39杀灭不同宿主菌作用无显著影响,与营养肉汤中的PL39杀菌作用相比差异无统计学意义(P>0.05)。结论人血清和鼠血清中的不耐热物质均可影响噬菌体PL39对其宿主菌的杀灭作用。

Objective To investigate the effects of heat-labile substances in human serum and mouse serum on the a- bility of phage PL39 to kill different strains of Pseudomonas aeruginosa. Methods PL39-sensitive host bacteria were screening using the double layer agar technique, and their genetic differences were investigating based on ERIC-PCR fin- gerprinting. The bactericidal effect of PL39 on different strains of host bacteria was observed in fresh and heat-inactivated human serum and mouse serum, and the causes of differences in that bactericidal effect were also analyzed. Results Nine PL39-sensitive strains of host bacteria were screened. ERIC fingerprints of 7 strains differed significantly. All 9 of the host bacterial strains were completely resistant to the lysis of human serum and mouse serum. The activity of PL39 remained constant in the two types of serum, but the bactericidal effect of PL39 on the 9 strains of host bacteria was in- hibited in human serum. In mouse serum, PL39 had a bactericidal effect on the L39 strain to an extent, but it did not kill other bacterial strains. However, the bactericidal effect of PL39 on different host strains was fully restored in the two types of heat-inactivated serum （56 ℃, 30 min）, and this bactericidal effect did not differ significantly from that in nutri- ent broth （P〈0.05）. Conclusion Heat-labile substances in both human serum and mouse serum are important factors affecting the bactericidal effect of phage PL39 on different strains of host bacteria.