Loss of resistance to ingestion and phagocytic killing by O- and K- mutants of a uropathogenic Escherichia coli O75:K5 strain

被引:38
作者
Burns, SM [1 ]
Hull, SI [1 ]
机构
[1] Baylor Coll Med, Dept Microbiol & Immunol, Houston, TX 77030 USA
关键词
D O I
10.1128/IAI.67.8.3757-3762.1999
中图分类号
R392 [医学免疫学]; Q939.91 [免疫学];
学科分类号
100102 ;
摘要
To determine the importance of the O75 O antigen and the K5 capsular antigen in resistance to phagocytosis and phagocytic killing, we used previously described O75(-) and K5(-) mutants from an O75(+) K5(+) wild-type uropathogenic Escherichia coli strain in phagocytosis assays with polymorphonuclear leukocytes (PMNs) and monocytes. At a 10-to-1 ratio of bacteria to phagocytes and in the presence of 10% serum, the parental strain GR-12 was resistant to both PMNs and monocytes over a 2-h incubation period. The O75(-) and K5(-) mutants were similar in sensitivity to killing by both PMNs and monocytes, decreasing in viability by 80% in the first hour. Yet, a significant difference in killing between the O75(-) and K5(-) mutants was observed in the first 15 min of incubation. The K5(-) mutant decreased in numbers by almost 60%, while the O75(-) mutant increased in numbers similarly to GR-12 in the first 15 min. The difference in killing was found not to be due to the rate of opsonization. To further determine the mechanism of resistance, a fluorescence assay was used to differentiate attached and internalized bacteria. The K5 capsule hindered the association of both the wild-type strain and the O75(-) mutant in the initial incubation time with PMNs. In conclusion, both the K5 capsule and O75 O antigen play crucial roles in resistance to phagocytosis over time.
引用
收藏
页码:3757 / 3762
页数:6
相关论文
共 35 条
  • [1] ACHTMAN M, 1986, ANNU REV MICROBIOL, V40, P185, DOI 10.1146/annurev.mi.40.100186.001153
  • [2] ALLEN PM, 1987, INFECT IMMUN, V40, P359
  • [3] RESISTANCE OF ENTEROCOCCUS-FAECIUM TO NEUTROPHIL-MEDIATED PHAGOCYTOSIS
    ARDUINO, RC
    JACQUESPALAZ, K
    MURRAY, BE
    RAKITA, RM
    [J]. INFECTION AND IMMUNITY, 1994, 62 (12) : 5587 - 5594
  • [4] Burns SM, 1998, INFECT IMMUN, V66, P4244
  • [5] CROSS AS, 1990, CURR TOP MICROBIOL, V150, P87
  • [6] THE IMPORTANCE OF THE K1 CAPSULE IN INVASIVE INFECTIONS CAUSED BY ESCHERICHIA-COLI
    CROSS, AS
    GEMSKI, P
    SADOFF, JC
    ORSKOV, F
    ORSKOV, I
    [J]. JOURNAL OF INFECTIOUS DISEASES, 1984, 149 (02) : 184 - 193
  • [7] DENSEN P, 1980, REV INFECT DIS, V2, P817
  • [8] Grunwald U, 1996, J IMMUNOL, V157, P4119
  • [9] INFLUENCE OF THE ESCHERICHIA-COLI CAPSULE ON COMPLEMENT-FIXATION AND ON PHAGOCYTOSIS AND KILLING BY HUMAN PHAGOCYTES
    HORWITZ, MA
    SILVERSTEIN, SC
    [J]. JOURNAL OF CLINICAL INVESTIGATION, 1980, 65 (01) : 82 - 94
  • [10] HORWITZ MA, 1982, REV INFECT DIS, V4, P104