Abstract
Purpose: :
To determine the incidence and trend of methicillin resistance among Staphalococcus in culture positive endophthalmitis over the past twenty years.
Methods: :
A retrospective, laboratory-based study of consecutive microbiological isolates. All culture positive Staphalococcus endophthalmitis isolates collected from 1987 through 2006 were identified. Antibiotic sensitivities with percent susceptible to methicillin were calculated and grouped into four five-year intervals (1987-91), (1992-96), (1997-01), (2002-06). Chi squared test for trend was used to detect changes over time in percent susceptibility.
Results: :
Four hundred eleven staphylococcus isolates (52%) of 794 isolates were identified. Two hundred fifty five isolates (62%) were staphylococcus epidermidis, 90 (22%) were Staphylococcus aureus, and 66 (16%) were other coagulase-negative Staphlococcus. From the interval of 1987-91 to 2002-06, Staphylococcus aureus and Staphylococcus epidermidis resistance to methicillin increased from 8% to 59% (p = 0.02) and from 31% to 58% (p = 0.007), respectively. There was no trend of increasing methicillin resistance among the other coagulase negative Staphylococcus.
Conclusions: :
Staphylococcus species are the most frequently identified cause of endophthalmitis. Percentages of Staphylococcus resistant to methacillin have increased 6 fold for Staphylococcus aureus and 2 fold for Staphylococcus epidermidis over the past 20 years.
Keywords: endophthalmitis • microbial pathogenesis: clinical studies • retina