Antimicrobial prescribing guidelines and policies should be revised for ophthalmic infections in the United Kingdom, according to a study published in BMC Infectious Diseases.

Bacterial ophthalmic infections are common and can range in severity from self-limiting bacterial conjunctivitis to potentially sight-threatening conditions. Although not required, antimicrobials may accelerate symptom resolution when treating self-limiting bacterial conjunctivitis, resulting in a reduction of health care and societal burden for this condition. Antimicrobials are also indicated for the treatment of corneal abrasion and bacterial keratitis. Empiric antimicrobial treatment is often recommended for severe infections, even before antimicrobial susceptibility results are known. This may result in the prescription of an antimicrobial to a pathogen that is resistant to this therapy, which puts the patient at risk for treatment failure.

Internationally, concerns about antimicrobial resistance have been increasing. This has resulted in an emphasis on antimicrobial stewardship, which promotes thoughtful antibiotic use in attempt to preserve their future efficacy and includes prescribing antimicrobials in relation to local resistance patterns. However, there is a lack of available data on epidemiology and susceptibility patterns of ophthalmic pathogens in the United Kingdom. Therefore, this retrospective, multicenter, observational study evaluated the epidemiology and antimicrobial susceptibilities of ophthalmic pathogens across care settings and compared these results with local and national antimicrobial prescribing guidelines.

In total, 2681 ophthalmic microbiology isolates were collected from 2168 patients between 2009 and 2015. In primary care settings, 29.5% of isolates were obtained from adults and 70.2% of isolates were obtained from children. In secondary care settings, 39.8% of isolates were obtained from adults and 60.2% of isolates were obtained from children. In tertiary care settings, 91.2% of isolates were obtained from adults and 8.8% of isolates were obtained from children. Isolates were obtained from eye swabs (88.0%), conjunctival swabs (3.7%), contact lens swabs (2.0%), corneal scrapes (5.5%), and invasive samples (0.8%).

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Staphylococcus spp was the most common pathogen in adults across primary (51.7%), secondary (43.4%), and tertiary (33.6%) care, with S aureus being the most prevalent species as the causative agent of infection in these cases. Haemophilus spp was the most common pathogen in children across primary (34.6%), secondary (28.2%), and tertiary (36.6%) care, with H influenza as the most common etiologic species.

Antimicrobial resistance was high and increased across care setting for chloramphenicol (which increased significantly from primary care settings [11.8%] to tertiary care settings [33.8%], P <.01), moxifloxacin, and fusidic acid. The most common chloramphenicol-resistant pathogen across all care settings was Pseudomonas spp. The most common moxifloxacin-resistant pathogen across all care settings was also Pseudomonas spp; however, fewer isolates were tested for moxifloxacin susceptibility than for chloramphenicol and fusidic acid susceptibility. The most common fusidic acid-resistant pathogen across primary and secondary care was Haemophilus spp; the most common in tertiary care etiologic pathogen was Staphylococcus spp. Fusidic acid-resistance was similar between primary and secondary care but significantly increased in tertiary care (P <.01). Because of a significant rise in Haemophilus spp during the spring among both adults and children (P <.001), there were more isolates recorded in spring (31.6%) than in any other season (P <.001).

Overall, the study authors concluded that, “Such findings highlight the need to reassess ophthalmic antimicrobial prescribing policies in the UK in accordance with local resistance patterns. This may include earlier adoption of alternative agents for bacterial conjunctivitis such as moxifloxacin, and tailoring prescribing policies by patient age and clinical setting.”

Reference

Lee AE, Niruttan K, Rawson TM, Moore LS. Antimicrobial resistance in ophthalmic infections: a multi-centre analysis across UK care settings. BMC Infect Dis. 2019;19:768.