Antimicrobial management of presumed microbial keratitis: guidelines for treatment of central and peripheral ulcers

Abstract

Aims-To determine the quantitative relation between the major risk factors for microbial keratitis of previous ocular surface disease and contact lens wear and central and peripheral infiltration, often associated with ulceration, in order to establish a rational chemotherapeutic management algorithm. Methods-Data from 55 patients were collected over a 10 month period. All cases of presumed microbial keratitis where corneal scrapes had been subjected to microbiological examination were included. Risk factor data and laboratory outcome were recorded. Antimicrobial regimens used to treat each patient were documented. (Br J Ophthalmol 1998;82:137-145) Results-57

Incidence and risk factors for microbial keratitis in Hong Kong: comparison with Europe and North America

“…The incidence of presumed MK for CLW (soft and rigid combined) was 3.4 per 10 000 lens wearers which is similar to that found in a recent study from Holland of 2.67 per 10 000 4 and 2.44 per 10 000 in Scotland, 2 latter study the number of expected cases of culturenegative MK was estimated from previous work in Glasgow. 12 CLW patients with presumed MK were much younger (90% Ͻ40 years) than the non-CLW patients (75% Ͼ40 years) and were more likely to be female (2:1 ratio). Distribution between left and right eyes was similar.…”

“…They recorded a worse prognosis for corneal lesion Ͼ4 mm 2 reflecting our experience and that of Scotland. 12 The CLWs had a peak incidence of MK at age 22 while the non-CLW patients showed a peak increase for MK in the age range 70-74 (Figure 1). This trend in the non-CLWs is 10 years earlier than that found in Scotland 2 and the USA, 1 perhaps reflecting the socioeconomic conditions.…”

“…13 The relationship between lesion size in square mm (mm 2 ) and culture-positivity has been found helpful previously in Scotland when a size of 4 mm 2 or greater was expected to be culture-positive associated with cells in the anterior chamber. 12 Rattanatam et al 13 have experienced a similar situation in Philadelphia, USA (Wills Eye Hospital) when they found that lesions of 2-4 mm 2 healed in 7 days but those Ͼ4 mm 2 required an average of 41 days. They recorded a worse prognosis for corneal lesion Ͼ4 mm 2 reflecting our experience and that of Scotland.…”

“…This is typical of a tropical climate but very different to that of a temperate one. 2,7,8,12 Patients with presumed MK, returning from a hot tropical climate to a temperate one, should always be treated for a possible Pseudomonas aeruginosa infection before culture results are known, as it is the commonest expected bacterium. Fungal infection occurred less commonly than expected, with one fungal case for every 17 bacterial cases.…”

The potential of desferrioxamine-gallium as an anti- Pseudomonas therapeutic agent

“…The antibiotic used in this study was gentamicin, the leading anti-Pseudomonas ocular agent. The accepted first line of treatment in clinical bacterial keratitis usually also includes a first or second generation cephalosporine (often Cefazolin or Cefuroxime 5%) (34). However, the cephalosporins are used in this context to cover Gram-positive bacteria and not to enhance the action of aminoglycosides on Gram-negative rods.…”