TABLE 1.
Strains and their mean fluorescence intensity values according to the flow cytometric serotyping assay
| Strain | Serotypea | FCSA MFIb |
FCSA serotype | Isolation tissue | cps locus genetics | |
|---|---|---|---|---|---|---|
| Hyp11AM1 | Hyp11AG2 | |||||
| Clinical isolates | ||||||
| MNZ264 | 11E | 44.2 (+) | 2.8 (−) | 11E | Blood | |
| MNZ268 | 11E | 40.0 (+) | 2.6 (−) | 11E | Blood | |
| MNZ741 | 11E | 16.6 (+) | 2.7 (−) | 11E | Blood | |
| MNZ267 | 11E | 71.6 (+) | 2.7 (−) | 11E | Blood | |
| MNZ265 | 11E | 69.7 (+) | 5.5 (low) | 11Av | Blood | |
| MNZ2322 | 11E | 117.9 (+) | 6.2 (low) | 11Av | Conjunctiva | |
| MNZ2293-C | 11E | 160.0 (+) | 12.7 (low) | 11Av | Blood | |
| 3102-06 | − | 101.8 (+) | 19.7 (low) | 11Av | Blood | |
| MNZ2292 | 11E | 172.0 (+) | 44.0 (low) | 11Av | Blood | |
| MNZ2293-A | 11A | 320.7 (+) | 1,076.2 (high) | 11A | Blood | |
| MNZ272 | 11A | 170.1 (+) | 1,460.9 (high) | 11A | Blood | |
| MNZ273 | 11A | 170.7 (+) | 1,601.6 (high) | 11A | Blood | |
| MNZ271 | 11A | 150.3 (+) | 1,789.0 (high) | 11A | Blood | |
| MNZ274 | 11A | 155.1 (+) | 2,201.0 (high) | 11A | Blood | |
| MNZ2321 | 11A | 132.5 (+) | 2,452.0 (high) | 11A | Conjunctiva | |
| Recombinant strains | ||||||
| JC01 | 9V | 3.3 (−) | 2.8 (−) | NTc | ||
| JC03 | − | 450.5 (+) | 570.4 (high) | 11A | MNZ270 rpsL::rpsL TIGRd | |
| JC04 | − | 397.2 (+) | 2.6 (−) | 11E | JC03 wcjE::Januse | |
| JC12 | − | 150.1 (+) | 11.3 (low) | 11Av | JC04 Janus::wcjE 3102-06 | |
| JC13 | − | 154.2 (+) | 2.6 (−) | 11E | JC04 Janus::wcjE MNZ741 | |
| AMB01 | − | 309.1 (+) | 743.6 (high) | 11A | JC04 Janus::wcjE MNZ2321 | |
| AMB02 | − | 153.6 (+) | 7.6 (low) | 11Av | JC04 Janus::wcjE MNZ2322 | |
| AMB03 | − | 3.1 (−) | 2.6 (−) | NTc | JC03 wchA-wcrL::Janus | |
Previously reported serotype for each strain (2, 5, 6). −, strains were first analyzed in this study. All examined clinical isolates were typed as 11A by conventional polyclonal serum-based serotyping methods.
In FCSA experiments, bacteria were stained with Hyp11AM1 or Hyp11AG2 murine monoclonal antibodies (MAbs) and anti-murine IgM or anti-murine IgG secondary antibodies, respectively. MFI values determined after staining with each MAb in a representative experiment are shown. MFI values were considered negative (−) if they were indistinguishable from negative-control values (i.e., MFI values of <4.0). Hyp11AM1 MFI values were considered positive (+) if they were greater than 4. Hyp11AG2 MFI values were considered high if they were at least 100-fold greater than the negative-control values (i.e., MFI of >400.0) and low if they were greater than negative-control values but less than 400.
NT, nontypeable by 11A/11E FCSA. AMB03 was determined to be nonencapsulated according to colony morphology and loss of reactivity with MAbs and serotyping factor sera.
The rpsL TIGR allele mediates streptomycin resistance (7).
The Janus cassette encodes kanamycin resistance (see Materials and Methods).