* Conflicts of Interest: The authors have no conflicts to disclose.
This study analyzed clinical characteristics of
The authors performed a retrospective chart review of 46 isolates in 46 eyes with
Among 46 eyes, MRSA was present in 15 eyes (33%) and MSSA in 31 eyes (67%). Male (61%) and older than 60 year-old group (48%) were common. Ocular surface disease/ocular surgery history and trauma were more common as a predisposing factor. Vancomycin was 100% sensitive to both the MRSA and MSSA groups. Antibiotics susceptibility to MRSA was significantly low in the oxacillin (0%), gentamicin (13.3%) and trimethoprim/sulfamethoxazole (53.3%) groups. Sensitivity to fluoroquinolone was 81.3% (MRSA 64.3% vs. MSSA 94.4%;
Among eyes with
Comparison of demographics and clinical course of keratitis caused by MRSA and MSSA
| No. of cases (%) | ||||
|---|---|---|---|---|
| Characteristics | All cases (n = 46) | MRSA (n = 15) | MSSA (n = 31) | |
| Gender (M/F) | 28/18 | 9/6 | 19/12 | 0.933 |
| Age (year) | 0.855 |
|||
| ≥60 | 22 (47.8) | 7 (46.7) | 15 (48.4) | |
| 40-59 | 15 (32.6) | 5 (33.3) | 10 (32.2) | |
| 20-39 | 5 (10.9) | 1 (6.7) | 4 (12.9) | |
| <20 | 4 (8.7) | 2 (13.3) | 2 (6.5) | |
| Symptom to treatment interval (days) | 7.7 ± 7.7 | 6.5 ± 7.5 | 8.4 ± 7.9 | 0.444 |
| Duration of hospitalization (days) (n = 37) |
0.061 |
|||
| <7 | 4 (10.8) | 2 (20.0) | 2 (7.4) | |
| 7-14 | 28 (75.7) | 5 (50.0) | 23 (85.2) | |
| >14 | 5 (13.5) | 3 (30.0) | 2 (7.4) | |
| Seasonal distribution | 0.802 |
|||
| Spring (March-May) | 12 (26.1) | 5 (33.3) | 7 (22.6) | |
| Summer (June-August) | 13 (28.3) | 3 (20.0) | 10 (32.2) | |
| Autumn (September-November) | 10 (21.7) | 3 (20.0) | 7 (22.6) | |
| Winter (December-February) | 11 (23.9) | 4 (26.7) | 7 (22.6) | |
| Average follow up period (months) | 13.3 ± 21.5 | 16.7 ± 21.5 | 11.7 ± 21.7 | 0.464 |
Values are presented as mean ± SD unless otherwise indicated. MRSA = methicillin-resistant
Chi-square test.
Fisher’s exact test.
Independent
Patients were excluded who were not admitted (MRSA 5, MSSA 4).
Predisposing factors for MRSA and MSSA keratitis
| No. of cases (%) |
||||
|---|---|---|---|---|
| Predisposing factors | All cases (n = 46) | MRSA (n = 15) | MSSA (n = 31) | |
| Ocular surface disease & ocular surgery history | 18 (39.1) | 7 (46.7) | 11 (35.5) | 0.530 |
| Trauma | 17 (37.0) | 5 (33.3) | 12 (38.7) | 0.575 |
| Systemic comorbidities |
14 (30.4) | 7 (46.7) | 7 (22.6) | 0.170 |
| Previous use of topical antibiotics | 12 (26.1) | 3 (20.0) | 9 (29.3) | 0.723 |
| Previous use of topical steroid | 7 (15.2) | 4 (26.7) | 3 (9.7) | 0.193 |
| Contact lens wear | 3 (6.5) | 1 (6.7) | 2 (6.5) | 0.978 |
| Non-identifiable | 3 (6.5) | 1 (6.7) | 2 (6.5) | 1.000 |
Values are presented as n (%) unless otherwise indicated. MRSA = methicillin-resistant
Chi-square test.
Fisher’s exact test.
Total can be greater than 100% because of some patients with multiple predisposing factors.
Systemic comorbidities include diabetes (MRSA 4, MSSA 2), hypertension (MRSA 5, MSSA 5), thyroid disease (MRSA 1), and hepatitis (MRSA 1).
Initial clinical findings of MRSA and MSSA keratitis
| No. of cases (%) | ||||
|---|---|---|---|---|
| Clinical findings | All cases (n = 46) | MRSA (n = 15) | MSSA (n = 31) | |
| Location | 0.191 | |||
| Central |
31 (67.4) | 8 (53.3) | 23 (74.2) | |
| Peripheral |
15 (32.6) | 7 (46.7) | 8 (25.8) | |
| Infiltration size (mm²) | 0.169 | |||
| Small (<5) | 33 (71.7) | 13 (86.7) | 20 (64.5) | |
| Large (≥5) | 13 (28.3) | 2 (13.3) | 11 (35.5) | |
| Hypopyon | 0.497 | |||
| Yes | 13 (28.3) | 3 (20.0) | 10 (32.3) | |
| No | 33 (71.7) | 12 (80.0) | 21 (67.7) | |
Values are presented as n (%) unless otherwise indicated. MRSA = methicillin-resistant
Fisher’s exact test.
Corneal lesion is located within 1/2 radius from the center of the cornea.
Corneal lesion is located within 1/2 radius from the limbus.
Antibiotics susceptibility of MRSA and MSSA isolates for keratitis
| Antibiotics | Susceptibility (%, n1/n2 |
|||
|---|---|---|---|---|
| Antibiotics | All cases (n = 46) | MRSA (n = 15) | MSSA (n = 31) | |
| Oxacillin | 67.4 (31/46) | 0.0 (0/15) | 100.0 (31/31) | 0.000 |
| Penicillin | 13.3 (6/45) | 0.0 (0/14) | 19.4 (6/31) | 0.077 |
| Cephalosporin | 69.4 (25/36) | 8.3 (1/12) | 100.0 (24/24) | 0.000 |
| Ciprofloxacin | 76.9 (20/26) | 50.0 (5/10) | 93.8 (15/16) | 0.018 |
| FQ (3rd & 4th generation) | 100.0 (6/6) | 100.0 (4/4) | 100.0 (2/2) | 1.000 |
| Gentamicin | 54.3 (25/46) | 13.3 (2/15) | 74.2 (23/31) | 0.000 |
| Erythromycin | 68.2 (15/22) | 28.6 (2/7) | 86.7 (13/15) | 0.006 |
| Clindamycin | 80.0 (8/10) | 50.0 (2/4) | 100.0 (6/6) | 0.053 |
| Tetracycline | 77.8 (7/9) | 50.0 (2/4) | 100.0 (5/5) | 0.073 |
| TMP/SMX | 75.6 (34/45) | 53.3 (8/15) | 86.7 (26/30) | 0.026 |
| Teicoplanin | 95.6 (43/45) | 86.7 (13/15) | 100.0 (30/30) | 0.755 |
| Linezolid | 100.0 (22/22) | 100.0 (7/7) | 100.0 (15/15) | 1.000 |
| Vancomycin | 100.0 (46/46) | 100.0 (15/15) | 100.0 (31/31) | 1.000 |
Values are presented as n (%) unless otherwise indicated. MRSA = methicillin-resistant
‘n1’ means number of isolates with susceptibility and ‘n2’ means number of tested isolates
Fisher’s exact test.
Treatment and clinical outcome of MRSA and MSSA keratitis
| No. of cases (%) | ||||
|---|---|---|---|---|
| All cases (n = 46) | MRSA (n = 15) | MSSA (n = 31) | ||
| Number of hospitalized patient | 37 (80.4) | 10 (66.7) | 27 (87.1) | 0.127 |
| Modification of antibiotics | 11 (23.9) | 2 (13.3) | 9 (29.0) | 0.296 |
| Surgical intervention |
10 (21.7) | 1 (6.7) | 9 (29.0) | 0.132 |
| Severe complications |
6 (13.0) | 1 (6.7) | 5 (16.1) | 1.000 |
| Epithelial healing time (days) (n = 40) |
0.481 |
|||
| <7 | 10 (25.0) | 5 (35.7) | 5 (19.2) | |
| 8-14 | 15 (37.5) | 5 (35.7) | 10 (38.5) | |
| >15 | 15 (37.5) | 4 (28.6) | 11 (42.3) | |
| Initial BCVA (Snellen acuity) (n = 45) |
||||
| ≥0.5 | 11 (24.4) | 3 (21.4) | 8 (25.8) | |
| 0.1-0.4 | 13 (28.9) | 5 (35.7) | 8 (25.8) | |
| <0.1 | 21 (46.7) | 6 (42.9) | 15 (48.4) | 0.841 |
| Final BCVA (Snellen acuity) (n = 45) |
||||
| ≥0.5 | 20 (44.4) | 6 (42.9) | 14 (45.2) | |
| 0.1-0.4 | 9 (20.0) | 2 (14.2) | 7 (22.6) | |
| <0.1 | 16 (35.6) | 6 (42.9) | 10 (32.2) | 0.771 |
| Clinical outcome |
||||
| Good | 20 (44.4) | 6 (42.9) | 14 (45.2) | |
| Moderate | 7 (15.6) | 2 (14.2) | 5 (16.1) | |
| Poor | 18 (40.0) | 6 (42.9) | 12 (38.7) | 1.000 |
Values are presented as n (%) unless otherwise indicated. MRSA = methicillin-resistant
Surgical interventions include amniotic membrane transplantation (AMT) (AMT only 3 eyes, AMT with excimer laser phototherapeutic kera-tectomy 1 eye, AMT and evisceration 1 eye), conjunctival flap (conjunctival flap only 1 eye, conjunctival flap and evisceration 1 eye), and evis-ceration only 3 eyes.
Severe complications include corneal perforation and/or endophthalmitis with surgical interventions of evisceration (MRSA 1, MSSA 4) and conjunctival flap (MSSA 1).
Six eyes were excluded if severe complications occurred (1 case for MRSA and 5 cases for MSSA).
One eye was excluded if the record for final BCVA was missed
Chi square test
Fisher’s exact test
Good: final BCVA ≥ 0.5, and no complications or surgical intervention, and no decrease in visual acuity (VA); Moderate: final BCVA 0.1-0.4, and no complications or surgical intervention, and no decrease in VA; Poor: final BCVA < 0.1, or decrease in VA, or complication of infection, or requiring surgical intervention.11
Multivariate logistic regression analysis for risk factors of poor visual outcome in
| Factor | Poor visual outcome |
||
|---|---|---|---|
| Factor | Odds ratio | 95% CI | |
| Age ≥ 60 years | 0.82 | 0.11-6.27 | 0.846 |
| Systemic disease (+) | 1.58 | 0.17-15.20 | 0.691 |
| Central corneal lesion | 0.37 | 0.03-4.71 | 0.443 |
| Size of epithelial defect ≥5 mm2 | 3.01 | 0.17-52.91 | 0.452 |
| Hypopyon (+) | 8.82 | 0.62-124.73 | 0.107 |
| Initial BCVA less than 0.1 | 16.82 | 1.26-224.03 | 0.033 |
| Epithelial healing time ≥10 days | 3.55 | 0.46-27.49 | 0.226 |
CI = Confidence interval; BCVA = best corrected visual acuity.
Poor visual outcome (n = 18) means the eyes which had poor visual outcome of the final best corrected visual acuity of 0.1 or less.
Multivariate logistic regression analysis was performed for the factors which had