TABLE 2.
Adherence of M. catarrhalis strains to human cells in vitro
| Strain | Description | % Adherencea
|
||
|---|---|---|---|---|
| A549b | HMEEc | Changd | ||
| O35E | wild type, opaque colony morphology | 40.5 ± 4.5 | 27.9 ± 4.2 | 17.4 ± 2.7 |
| O35E.TN2 | Tn mutant, transposon in hag gene, opaque colony morphology | 1.3 ± 0.3*f | 0.7 ± 0.1* | NDe |
| O35E.1 | Isogenic uspA1 mutant, opaque colony morphology | ND | ND | 1.5 ± 0.4* |
| O35E.TN52g | Tn mutant, transposon in ompCD gene, transparent colony morphology | 2.6 ± 0.4* | 23.9 ± 4.4 | 14.9 ± 1.8 |
| O35E.TN313g | Tn mutant, transposon in ompCD gene, transparent colony morphology | 4.4 ± 1.5* | ND | ND |
| O35E.TN593g | Tn mutant, transposon in ompCD gene, transparent colony morphology | 1.3 ± 0.2* | ND | ND |
| O35E.TN649g | Tn mutant, transposon in ompCD gene, transparent colony morphology | 0.8 ± 0.2* | ND | ND |
| O35E.CD1 | Isogenic ompCD mutant, transparent colony morphology | 5.1 ± 0.9* | ND | 16.1 ± 2.9 |
a
Adherence is expressed as the mean (± standard error) percentage of bacteria binding to monolayers.
b
Strains were incubated for 3 h with A549 cells prior to washing unbound bacteria.
c
Strains were incubated for 15 min with HMEE cells prior to washing unbound bacteria.
d
Strains were incubated for 15 min with Chang cells prior to washing unbound bacteria.
e
ND, not determined.
f
*, the difference in the P value compared to the value for the wild-type strain O35E was found to be statistically significant using a Mann-Whitney test.
g
Transposon mutants were first identified due to their reduced binding to A549 cells in microcolony formation assays.