Table 3.
A summary of the recent evidence on the use of polymerase chain reaction (PCR) in the diagnosis of a range of infectious keratitis.
| Year | Authors | Sample size | Technique | Target region | Sen (%) | Spec (%) | Comparison (if any) |
|---|---|---|---|---|---|---|---|
| Bacterial keratitis | |||||||
| 2020 | KrishnanNair et al. [74] | 100 | Multiplex qPCR | Species specific DNA region | 100 | 100 | – |
| 2019 | Wagner et al. [75] | 499 | qPCR | 16S rDNA | 94.5 | 100 | – |
| 2019 | Shimizu et al. [76] | 118 | qPCR | 16S rDNA | 63.6 | 67.5 | Culture = 51.8 (Sen), 77.2 (Spec); Smear = 63.1 (Sen), 89.8 (Spec) |
| 2017 | Fang et al. [77] | 61 | DBH | 16S rDNA | 81.3–93.8 | 71.1–100 | – |
| 2015 | Panda et al. [78] | 122 | qPCR | 16S rDNA | 89 | 87 | Smear = 45.3 (Sen), 92.8 (Spec) |
| Fungal keratitis | |||||||
| 2020 | Kulandai et al. [79] | 42 | qPCR | 18S RNA & ITS | 98.2 | 100 | – |
| 2020 | Ren et al. [80] a | 35 | qPCR | ITS | 74.3 | – | IVCM = 77.1; Smear = 77.1; Culture = 71.4 |
| 2018 | Wagner et al. [81] | 233 | qPCR (18S rDNA), semi-nested qPCR (ITS) | 18S rDNA, ITS |
97.8 (18S) 86.7 (ITS) |
100 (18S) 100 (ITS) |
– |
| 2015 | Haghani et al. [82] | 40 | Semi-nested PCR | ITS | 57.1 | 78.7 | Smear = 28.5–42.0 (Sen), 78.7–94.0 (Spec) |
| 2014 | Zhao et al. [83] | 80 | Touchdown PCR | ITS | 98.0 | 81.8 | Culture = 47.1 (Sen), 100 (Spec) |
| Acanthamoeba keratitis | |||||||
| 2018 | Goh et al. [84] | 25 | qPCR | 18S rDNA | 71.0 | 100 | Culture = 33.3 (Sen), 100 (Spec); IVCM = 100 (Sen), 100 (Spec) |
| 2017 | Karsenti et al. [85] | 107 | qPCR | 18S rDNA | 100 | 96.0 | – |
| 2017 | Mewara et al. [86] | 42 | PCR, LAMP | 18S rDNA | 100 (PCR, LAMP) | 100 (PCR, LAMP) | Smear = 60 (Sen), 100 (Spec); Culture = 100 (Sen), 100 (Spec) |
| 2016 | Huang et al. [87] | 20 | DBH | 18S rDNA | 87.5 | 100 | – |
| 2015 | Kowalski et al. [88] | 125 | PCR | 18S rDNA | 85.7 | 100 | Culture = 81.0 (Sen), 100 (Spec) |
| Viral keratitis | |||||||
| 2019 | Brunner et al. [89] a | 110 | qPCR | HSV DNA | 25.5–43.8 | – | – |
| 2019 | Guda et al. [90] | 50 | Multiplex qPCR | HSV and VZV DNA | 100 | 28 | – |
| 2018 | Inata et al. [91] a | 38 | qPCR | VZV DNA | 84.2 | – | – |
| 2016 | Ma et al. [92] a | 30 | qPCR | HSV DNA | 46.4 | – | – |
| 2016 | Kuo et al. [93] b | 33 | Multiplex DBH | HSV DNA | 93.3 | 100 | – |
Sen = Sensitivity; Spec = Specificity; qPCR = Quantitative or real-time PCR; DBH = Dot-blot hybridization; rDNA = ribosomal DNA; ITS = Internal transcribed sequence; LAMP = Loop-mediated isothermal amplification; HSV = Herpes simplex virus; VZV = Varicella zoster virus.
a
These studies reported the detection rate.
b
This study examined both Acanthamoeba keratitis and herpes simplex keratitis.