Table 1.
Characterization of Staphylococcus aureus isolates by clinical source, diagnosis, antibiotic susceptibility pattern, and biofilm formation under different growth conditions using a crystal violet biomass assay. The strongest biofilm clinical isolates are shown at late log growth at 20, 48, and 96 h. A relative biofilm robustness scale (0 – 5) was developed based on 595 nm absorbance readings (Scale: absorbance <0.5 = 0; 0.5 - 0.99 = 1; 1.0 - 1.49 = 2; 1.5 - 1.99 = 3; 2.0 - 2.49 = 4; >2.5 = 5). MSSA, methicillin-sensitive S. aureus; MRSA, methicillin-resistant S. aureus; Cp-R, ciprofloxacin-resistant; Em-R, erythromycin-resistant; BHI, brain heart infusion; TSB, trypticase soy broth; LB, Luria-Bertoni; suc, sucrose; glc, glucose.
| Strain | Clinical Source | Diagnosis | Antibiotic susceptibility | Biofilm Formation Robustness Scale (0-5) Media and time | ||||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| BHI 2% suc (h) | TSB 2% glc (h) | LB 1% glc (h) | TSB 0.25% glc (h) | LB 0.1% glc (h) | ||||
|
| ||||||||
| MEEI-IB001 | Cornea (15) | Keratitis | MSSA Cp-R; Em-R | 5 (24) | 3 (24) | 1 (24) | 1 (24) | |
| 5 (48) | 1 (48) | 3 (48) | 1 (48) | |||||
| 5 (96) | 4 (96) | 2 (96) | 3 (96) | |||||
|
| ||||||||
| MEEI-IB002 | Cornea | Keratitis | MSSA Cp-R; Em-R | 5 (24) | 1 (24) | 1 (24) | ||
|
| ||||||||
| MEEI-IB003 | Cornea (15) | Keratitis | MSSA Em-R | 5 (24) | 1 (24) | 1 (24) | 1 (24) | |
| 4 (48) | 2 (48) | 4 (48) | 1 (48) | |||||
| 5 (96) | 5 (96) | 3 (96) | 2 (96) | |||||
|
| ||||||||
| MEEI-IB005 | Orbit | Orbital abscess | MSSA | 5 (24) | 1 (24) | 1 (24) | 0 (24) | |
| 5 (48) | 2 (48) | 3 (48) | 0 (48) | |||||
| 4 (96) | 5 (96) | 2 (96) | 2 (96) | |||||
|
| ||||||||
| MEEI-IB011 | Ear | Otitis media | MRSA Cp-R; Em-R | 5 (24) | 5 (24) | 2 (24) | 0 (24) | |
| 5 (48) | 4 (48) | 5 (48) | 5 (48) | |||||
| 5 (96) | 5 (96) | 3 (96) | 5 (96) | |||||
|
| ||||||||
| MEEI-IB012 | Upper lid (15) | Eyelid abscess | MSSA | 5 (24) | 3 (24) | 1 (24) | ||
|
| ||||||||
| MEEI-IB013 | Canniculus (15) | Canniculitis | MSSA | 5 (24) | 2 (24) | 0 (24) | ||
|
| ||||||||
| MN8 | Vagina (19) | Toxic shock syndrome | MSSA | 2 (24) | 1 (24) | |||
| 4 (48) | 3 (48) | 5 (48) | 0 (48) | |||||
| 5 (96) | 2 (96) | 2 (96) | 3 (96) | |||||
|
| ||||||||
| MN8 mucoid | Chemostat culture (18) | PNAG hyperbiofilm MN8 mutant | MSSA | 4 (24) | 4 (24) | |||
| 5 (48) | 5 (48) | 5 (48) | 5 (48) | |||||
| 5 (96) | 5 (96) | 5 (96) | 3 (96) | |||||