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| Author | Place | Studied year | Total number of scrapes | Positive culture rate (%) | Distribution of isolates | Commonest isolate (descending order) | Other significant findings |
|
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Alexandrakis et al. (2000) [4] | South Florida, USA | 1990–1998 (9 years) | 2920 | 50% (1468) | Gram+: 48%
Gram−: 50% | (i) Pseudomonas
(ii) Staphylococcus aureus | (i) Increasing fluoroquinolone resistance of Staphylococcus aureus keratitis
(ii) Increasing prevalence of Staphylococcus Aureus
(iii) Decreasing prevalence of Pseudomonas
(iv) Main risk factor: contact lens (Pseudomonas and Serratia most common in this subgroup) |
|
| Bourcier et al. (2003) [8] | Paris, France | January 1998–September 1999 (21 months) | 300 | 68% (201) | Gram+: 83%
Gram−: 17% | (i) Coagulase-negativeStaphylococcus
(ii) Proprionibacterium acnes
(iii) Pseudomonas | (i) Gram-negative bacteria associated with more severe anterior chamber inflammation and larger infiltrate
(ii) Main risk factor: contact lens: 50.2%; keratopathy: 21%; trauma 15%
(iii) Coagulase-negativeStaphylococcus most common in contact lens-keratitis
(iv) Outcome: 99% respond to treatment; 5% very poor outcome |
|
| Butler et al. (2005) [9] | Sydney, Australia | September 1998–December 2002 (4 years 3 months) | 190 | 62.8% (119) | Gram+: 75%
Gram−: 25% | (i) Coagulase-negative Staphylococcus
(ii) Staphylococcus aureus
(iii) Pseudomonas | (i) All cases >60 years old (average age: 75.5)
(ii) Local risk factors: 93.7%; systemic risk factors: 27.9%
(iii) 7.9% HSV PCR+, which was associated with more perforation or severe thinning (80% versus overall 36%)
(iv) Outcome: 17.9% PKP; 8.9% evisceration |
|
| Toshida et al. (2007) [10] | Japan | 1999–2003 (5 years) | 123 | 58.5% (72) | Gram+: 77.8%
Gram−: 18.2%
Fungi: 6.1%
Acanthamoeba: 1.0% | (i) Staphylococcus
(ii) Streptococcus
(iii) Corynebacterium | Main risk factor: contact lens 54.5%; ocular surface disease 20.5%; previous ocular surgery 13.1% |
|
| Green et al. (2008) [11] | Australia | 1999–2004 (5 years) | 253 | 65% (164) | — | (i) Pseudomonas
(ii) Coagulase-negative Staphylococcus
(ii) Staphylococcus aureus | (i) 98% sensitivity to ciprofloxacin
(ii) 100% sensitivity to gentamicin (Gram-negative)
(iii) Main risk factor: contact lens 22%; ocular surface disease 18%; trauma 16%; prior surgery 11%
(iv) Ocular surface disease associated with more severe keratitis
(v) Fusarium, Pseudomonas, and Gram-negative organisms associated with more severe keratitis at time of scraping |
|
| Zhang et al. (2008) [3] | Beijing, China | 2001–2004 (4 years) | 1985 | 14.06% (279) | Gram+: 42.7%
Gram−: 35.1% | (i) Pseudomonas
(ii) Corynebacterium
(iii) Staphylococcus epidermidis | Increasing ciprofloxacin resistance in Gram-positive cocci & Gram-negative bacilli |
|
| Ibrahim et al. (2009) [12] | Portsmouth, UK | 1997–2003 (7 years) | 1254 | 63.8% (800) | Gram+: 71.1%
Gram−: 28.9% | (i) Staphylococcus epidermidis
(ii) Pseudomonas
(iii) Staphylococcus aureus | (i) Main risk factor: contact lens
(ii) Outcome: 1.9% poor visual outcome |
|
| Edwards et al. (2009) [13] | Melbourne, Australia | May 2001–April 2003 (2 years) | 88 | 78% (69) | — | Staphylococcus species | (i) Only studied contact lens-related keratitis
(ii) Outcome: contact lens wearer age group of 15–24 had increased risk |
|
| Saeed et al. (2009) [14] | Ireland | September 2001–August 2003 (2 years) | 90 | 36.6% (33) | Gram+: 33.3%
Gram−: 54.5% | (i) Pseudomonas
(ii) Coagulase-negative Staphylococcus
(iii) Staphylococcus aureus
(iv) Streptococcus pneumonia | (i) All studied cases were severe cases with hospital admission
(ii) Main risk factor: contact lens 41.1%; anterior segment disease 21.1%; trauma (14%) |
|
| Cariello et al. (2011) [15] | Sao Paulo, Brazil | July 1975–September 2007 (>30 years) | 6804 | 48.6% (3307) | Bacterial 81.6%
+: 71.2%
−: 27.0% | (i) Coagulase-negative Staphylococcus
(ii) Staphylococcus aureus
(iii) Pseudomonas | Main risk factors: corneal surgery, contact lens, and ocular trauma |
|
| Shalchi et al. (2011) [16] | East Kent, UK | 1999–December 2009 (10 years) | 476 | 34.2% (163) | Gram+: 38.9%
Gram−: 61.1% | (i) Pseudomonas
(ii) Staphylococcus
aureus
(iii) Coagulase-negative Staphylococcus | (i) Increase of Gram-negative isolates with time
(ii) Main risk factor: contact lens
(iii) Antibiotic sensitivity:
(a) High sensitivity to combination of gentamicin and cefuroxime, as well as ciprofloxacin.
(b) Trend of increasing resistance to chloramphenicol
(c) Gram-positive fluoroquinolone resistance remained |
|
| Pandita and Murphy (2011) [17] | Waikato, New Zealand | January 2003–December 2007 (5 years) | 265 | 65.6% (174) | Gram+: 78.2%
Gram−: 20.2% | (i) Coagulase-negative Staphylococcus (40.8%)
(ii) Staphylococcus aureus (11.5%)
(iii) Moraxella (8.0%)
(iv) Pseudomonas | (i) Fluoroquinolone: 99% sensitivity
(ii) Tobramycin: Gram-positive: 95.5% sensitivity; Gram-negative: 100%
(iii) Recommends fluoroquinolone monotherapy |
|
| Lichtinger et al. (2012) [1] | Toronto | 2000–2011
(11 years) | 1701 | 57.4% (976) | Gram+: 76.3%
Gram−: 23.7% | (i) Coagulase-negative Staphylococcus
(ii) Staphylococcus aureus
(iii) Pseudomonas | (i) Decreasing trend in Gram-positive isolate
(ii) Increasing methicillin resistance (29.1% of Gram-positive isolates)
(iii) 43.1% of coagulase-negative Staphylococcus were multiple resistant |
|
| Tananuvat et al. (2012) [18] | Northern Thailand | April 2003–March 2006 (3 years) | 310 | 25.6% (79) | Bacterial 49.3%
Fungal 46.3% | (i) Pseudomonas
(ii) Fusarium | (i) Main risk factor: 43.9% trauma; contact lens 3.5%
(ii) Outcome:
(a) Large ulcer >6 mm poor outcome
(b) 41% required surgical procedure, commonest scleral patch graft |
|
| Tewari et al. (2012) [19] | Ahmedaba, India | July 2007–June 2008 (1 year) | 150 | 59.3% (89) | Bacterial 65.1%
+: 60.3%
−: 39.7%
Fungal: 34.9% | (i) Staphylococcus
(ii) Coagulase-negative Staphylococci
(iii) Pseudomonas | (i) Aspergillis most common fungi, followed by Fusarium
(ii) Main risk factor: 90% trauma |
|
| Dhakhwa et al. (2012) [20] | Western Nepal | 2007 (1 year) | 414 | 72.5% (300) | Bacterial: 29.2%
Fungal: 33.3% | (i) Fusarium
(ii) Staphylococcus epidermidis | (i) Main risk factor: 33.3% trauma
(ii) Outcome: 87.7% completely healed |
|
| Hong et al. (2013) [21] | Shanghai, China | January 2005–December 2010 (6 years) | 1042 | 41.8% (436) | Gram+: 50%
Gram−: 46.3% | (i) Streptococcus species
(ii) Pseudomonas | (i) 8.3% methicillin-resistant Staphylococcus aureus (MRSA)
(ii) 53.1% multiple resistant coagulase-negative Staphylococci
(iii) Increasing fluoroquinolone resistance found |
|
| Ng (current study) | Hong Kong | January 2004–December 2013 | 347 | 32.3% (112) | Bacterial 90.8%
+: 57.6%
−: 42.4%
Fungal 9.2% | (i) Coagulase-negative Staphylococcus
(ii) Pseudomonas
(iii) Staphylococcus aureus | (i) Contact lens-related keratitis most common
(ii) No shifting trend in antibiotic resistance
(iii) Poor outcome associated with age, size of ulcer >3 mm, and trauma etiology |
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