Queensland Microbial Keratitis Database: 2005–2015

Abstract

AimsTo estimate the incidence of culture-positive microbial keratitis in Queensland and analyse trends in the organisms and their sensitivities cultured from corneal scrapes, especially low-incidence organisms.MethodsRetrospective multicentre case series of all positive corneal scrapes in Queensland, Australia between 2005 and 2015. Pathology organisations in Queensland were identified by online and local directory search and agreed to participate. Digital records of scrapes provided patient demographics and culture and susceptibility results. Trends in the incidence, organisms and sensitivities were monitored with linear regression. The yearly incidence of microbial keratitis was estimated from the Queensland population.ResultsThe included corneal scrapes totalled 3182, while 1006 were excluded. The included scrapes yielded 4111 organisms. Pseudomonas aeruginosa was the most common single isolate (729, 17.7%), although Gram-positive organisms were more common overall (2737, 66.6%). Fungal organisms were cultured in 6% of cases, while Acanthamoeba comprised only 1% of records. Bacterial organisms were sensitive to all recorded antibiotics in 89% of all isolates and none of the reported antibiotics showed a decreasing trend in susceptibility. The incidence of protozoal isolation decreased over time (p=0.055). Cultures positive for yeasts showed a linear increase in incidence (p=0.045) while moulds showed a spike in incidence in 2010–2012 (p=0.0008).ConclusionThe estimated incidence of microbial keratitis was 0.66 cases per 10 000 people, the rate of antibiotic susceptibility is high and stable, the incidence of keratitis secondary to protozoa is likely to be decreasing while the incidence of keratitis culturing yeast is increasing.

Antimicrobial resistance trends in bacterial keratitis over 5 years in Sydney, Australia

“…Our S aureus resistance to ciprofloxacin remained stable over the years, with a few cases in 2012 (2 of 23 [9%]), 2014 (2 of 24 [8%]) and 2016 (1 of 15 [7%]). Further, our ciprofloxacin resistance rates for CoNS (8.5%) and S aureus (5%) were comparable to the results from a recent Queensland study which reported 6% resistance for CoNS and 4% for S aureus . The Pittsburgh study reported a significant resistance of Streptococcus pneumoniae to ciprofloxacin (49.6%, 57 of 115) and ofloxacin (27%, 31 of 115) with no changes over time .…”

“…The number of Gram‐positive and Gram‐negative organisms were stable over our study period, in contrast to the significant increase in Gram‐positive bacteria found in Toronto or in Gram‐negative bacteria in Kent, United Kingdom . The predominant isolates were Gram‐positive organisms, with the majority being CoNS (405 of 884 [46%]); this finding was comparable with bacterial keratitis studies from Australia, United States, Israel, Canada, France and New Zealand . The proportion of CoNS was 48% in Toronto, 38% in Sydney, 37% in Los Angeles, 36.7% in Pittsburgh, 35% in Melbourne, 34% in Queensland and 30% in Adelaide …”

“…The predominant isolates were Gram‐positive organisms, with the majority being CoNS (405 of 884 [46%]); this finding was comparable with bacterial keratitis studies from Australia, United States, Israel, Canada, France and New Zealand . The proportion of CoNS was 48% in Toronto, 38% in Sydney, 37% in Los Angeles, 36.7% in Pittsburgh, 35% in Melbourne, 34% in Queensland and 30% in Adelaide …”

“…Surprisingly, the chloramphenicol resistance has slightly fallen comparing our findings with the previous study conducted in 2002 for the Staphylococci species; which were the main causing organism . Moreover, these falling trends were also found in Queensland for CoNS (10%) and for S aureus (4%) . On the other hand, the chloramphenicol resistance increased for Corynebacterium species.…”

“…These findings inform recent trends of the microbiological pattern and AMR profiles for bacterial keratitis in Australia. The last trends were reported in studies from Brisbane and Sydney more than 10 years ago, and in a recent study from the region of Queensland, Australia in early 2019 . Microbiological spectrum and antibiotic resistance profiles can vary across different regions and hospitals and fluctuate from time to time .…”