Prevalence ofVirulence Factors

The number (and percentages) of the various virulence factors are shown in Table 1.

Table 1. Characteristics of 111 isolated Escherichia coli. P-values of differences in numbers of virulence factors between cleared and persistent strains are given. Primers for type 1 fimbriae (type1), P fimbriae (papA), three alleles ofthe G-adhesinoftype P fimbriae (papG-I, papG-II, papG-III), S fimbriae (SFA), afimbrial adhesin (AFA), cytotoxic necrotizing factor (CNF), and aerobactin were used. O-UTI= known uropathogenic O-serotypes (O1, O2, O4, O6, O7, O8, O16, O18, O25, O75). Phenotypes were also determined: MSHA = mannose-sensitive hemagglutination; MRHA = mannose-resistant hemagglutination; and hemolysin.

Table 1. Characteristics of 111 isolated Escherichia coli. P-values of differences in numbers of virulence factors between cleared and persistent strains are given. Primers for type 1 fimbriae (type1), P fimbriae (papA), three alleles ofthe G-adhesinoftype P fimbriae (papG-I, papG-II, papG-III), S fimbriae (SFA), afimbrial adhesin (AFA), cytotoxic necrotizing factor (CNF), and aerobactin were used. O-UTI= known uropathogenic O-serotypes (O1, O2, O4, O6, O7, O8, O16, O18, O25, O75). Phenotypes were also determined: MSHA = mannose-sensitive hemagglutination; MRHA = mannose-resistant hemagglutination; and hemolysin.

Virulence Factors

Numbers in all strains (n=lll)

Numbers in persistent strains (n=15)

Numbers in cleared strains (n=19)

p-value

Typel

96 (86%)

13 (87%)

19(100%)

0.6

MSHA

65 (59%)

8 (53%)

15(79%)

0.6

PapA

22 (20%)

1 (7%)

3 (16%)

0.1

PapG-I

-

-

-

-

PapQ-II

5 (5%)

-

1 (5%)

0.4

PapG-III

16(14%)

1 (7%)

3 (16%)

0.3

SFA

33 (30%)

2 (13%)

5 (26%)

0.09

AFA

6 (5%)

2(13%)

-

0.2

MRHA

21 (19%)

1 (7%)

2(11%)

0.2

Aerobactin

35 (32%)

3 (20%)

7 (37%)

0.4

CNF

21 (19%)

1 (7%)

2(11%)

0.2

Hemolysis

36 (32%)

6 (40%)

7 (37%)

0.6

O-UTI

21 (19%)

-

2(11%)

0.05

The most prevalent virulence factor was type 1 fimbriae (86% by genotyping and 59% by phenotyping respectively). Genes coding for P or S fimbriae and known uropathogenic O-serotypes were more common in cleared than in persistent strains.

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