Di Martino P, Livrelli V, Sirot D, Joly B, Darfeuille-Michaud A
Laboratoire de Bactériologie, Facultés de Pharmacie et Médecine, Clermont-Ferrand, France.
Infect Immun. 1996 Jun;64(6):2266-73. doi: 10.1128/iai.64.6.2266-2273.1996.
We purified and characterized a new fimbria termed KPF-28 (Klebsiella pneumoniae fimbria with a fimbrin molecular mass of 28 kDa) involved in K. pneumoniae adherence to the human carcinoma cell line Caco-2. Electron microscopy of bacterial surface protein preparations and immunogold labeling of bacterial cells showed that KPF-28 was a long, thin, and flexible fimbria about 4 to 5 nm in diameter and 0.5 to 2 microm long. The N-terminal amino acid sequence of the KPF-28 major fimbrial subunit showed no homology with type 1 and type 3 pili of K. pneumoniae but showed 61.7% identity with residues 6 to 19 of the N-terminal amino acid sequence of PapA, the Pap major pilus subunit expressed by uropathogenic Escherichia coli strains. Total amino acid content determination showed that the KPF-28 major subunit composition was close to that of the GVVPQ fimbrial family major subunits expressed by pathogenic E. coli strains. The study of the prevalence of KPF-28 among K. pneumoniae strains involved in nosocomial infections revealed that KPF-28 was found in the great majority of the K. pneumoniae strains producing the CAZ-5/SHV-4 extended-spectrum beta-lactamase. As shown by curing and mating experiments, the R plasmid encoding the CAZ-5/SHV-4 enzyme was found to be involved in but not solely responsible for KPF-28 expression. Hybridization experiments using an oligonucleotide probe corresponding to the N-terminal part of the 28-kDa protein revealed that the structural gene encoding the KPF-28 major subunit was localized on this R plasmid. KPF-28 is a putative colonization factor of the human gut, since the ceftazidine-sensitive derivative strain CF914-1C no longer adhered and since the Fab fragments of antibodies raised against KPF-28 inhibited adhesion of K. pneumoniae CF914-1 to the Caco-2 cell line.
我们纯化并鉴定了一种新的菌毛，称为KPF-28（肺炎克雷伯菌菌毛，菌毛蛋白分子量为28 kDa），它参与肺炎克雷伯菌对人癌细胞系Caco-2的黏附。对细菌表面蛋白制剂的电子显微镜观察以及对细菌细胞的免疫金标记显示，KPF-28是一种长而细且柔韧的菌毛，直径约4至5 nm，长0.5至2微米。KPF-28主要菌毛亚基的N端氨基酸序列与肺炎克雷伯菌1型和3型菌毛无同源性，但与尿路致病性大肠杆菌菌株表达的Pap主要菌毛亚基PapA的N端氨基酸序列6至19位残基有61.7%的同一性。总氨基酸含量测定表明，KPF-28主要亚基组成与致病性大肠杆菌菌株表达的GVVPQ菌毛家族主要亚基相近。对医院感染相关肺炎克雷伯菌菌株中KPF-28流行情况的研究表明，在绝大多数产生CAZ-5/SHV-4超广谱β-内酰胺酶的肺炎克雷伯菌菌株中都发现了KPF-28。如消除和接合实验所示，编码CAZ-5/SHV-4酶的R质粒参与但并非唯一负责KPF-28的表达。使用对应于28 kDa蛋白N端部分的寡核苷酸探针进行的杂交实验表明，编码KPF-28主要亚基的结构基因位于该R质粒上。KPF-28是一种假定的人类肠道定植因子，因为头孢他啶敏感衍生菌株CF914-1C不再黏附，并且针对KPF-28产生的抗体的Fab片段可抑制肺炎克雷伯菌CF914-1对Caco-2细胞系的黏附。
