A recent study has revealed that coronavirus disease or COVID-19 has reduced presentation rates for microbial keratitis or MK and changed the spectrum of isolated cultures; however, no clear impact on results.
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What Is Microbial Keratitis?
Microbial Keratitis or most commonly known as Bacterial
Keratitis – is an infection of the cornea, the clear dome that covers the
colored part of the eye, that is caused by bacteria.
This usually happens due to improper care and cleaning
of contact lenses or from injury to the cornea. This bacterial infection can
affect those people who wear contact lenses, and also those people who do not
even wear contact lenses. Certain types of bacteria that commonly cause
microbial keratitis include; pseudomonas aeruginosa.
What Causes Microbial Keratitis?
Microbial Keratitis is usually caused by contact lens
wear; however, infection of the cornea can also result from exposure of the eyes
such as if the eyelids are not blinking normally, loss of sensation in the eye
surface, injury or surgery, lack of tears or known as dry eyes, and in people
whose immune system is not functioning properly.
How Is Microbial Dermatitis Treated?
Fortified antibiotics is the traditional therapy for
microbial keratitis. Tobramycin (1mg/mL) 1 drop for every hour alternating with
fortified cefazolin (50 mg/mL) or vancomycin (50mg/mL) 1 drop every hour.
How Common Is Microbial Dermatitis?
Microbial Keratitis is generally correlated with one
or more of the following: wearing of contact lenses, particularly soft lenses
that are worn overnight; incidence soft daily wear: 2-4 per 10,000 per year
(0.02% - 0.04% per year), soft overnight wear 20 per 10,000 per year or 0.2%
per year.
Medical records of suspected microbial keratitis (MK)
patients, were retrospectively reviewed by experts, requiring corneal scrapes
who presented between 23rd March and 30th June 2020. Results,
isolates, medications, and concurrent conditions were compared with patients
who presented in the equivalent time windows pre-COVID-19 in 2017, 2018, and
2019 respectively.
In total, 63, 50, and 68 patients who presented for
microbial keratitis (MK) during 2017, 2018, and 2019. There were only 49 patients
who did so during or at the onset of the pandemic, suggesting a slight decline
in presentation rates. Likewise, the total attendances to the clinic plummeted
from 12,128 and 12,239 in 2018 and 2019, correspondingly, to 5,759 in 2020. The
proportion of MK presentations, in turn, increased significantly from 0.5%
pre-COVID-19 to 0.9% at the height of the pandemic.
Rate of culture positivity was comparable between the
pre-COVID-19 and pandemic eras; however, the distribution of culture isolates
is different. Poly-microbial infection happened significantly more frequently
before the pandemic, while the gram-negative mono-infections tended to be more
predominant in year 2020.
Furthermore, regardless of comparable rates of disease
severity, the rate of admission was significantly reduced during the pandemic
era.
Researchers said that, “Increased handwashing practices,
as well as changes in environmental factors, such as reduced contact lens wear,
may have contributed to the findings, particularly the changes in microbial
spectra. However, these findings must be validated on a larger scale.”
Source: PLoS One 2021;doi:10.1371/journal.pone.0256240