Polymicrobial endophthalmitis: prevalence, causative organisms, and visual outcomes

Abstract

BackgroundThe purpose of the present study is to evaluate the prevalence, causative organisms, and visual acuity outcome in patients with culture-proven polymicrobial endophthalmitis. The method used in this study is the non-comparative, consecutive case series using a retrospective analysis of patients diagnosed with polymicrobial endophthalmitis for the period 2000 to 2010.ResultsPolymicrobial endophthalmitis was identified in 43/1,107 (3.88%) patients. Forty-two patients had two isolates, and one patient had grown three isolates, yielding a total of 87 isolates. Gram-positive cocci were the most common isolate (n = 53; 60.9%) including Staphylococcus epidermidis (n = 14/53; 16.1%) and Streptococcus pneumoniae (n = 13/53; 13.8%). The etiologies included posttraumatic (n = 31/43; 72.1%) and postoperative (n = 9/43; 20.9%) endophthalmitis. Antibiotic susceptibilities among Gram-positive bacteria were vancomycin (100%) and chloramphenicol (96%). Susceptibilities among Gram-negative bacteria were ciprofloxacin (86.4%) and ofloxacin (81.2%). A maximum number of secondary interventions were done in traumatic cases (38.7%) and cases having coinfection with Gram-negative bacteria and fungus (66.7%). Visual acuity (VA) < 20/200 was more frequently observed in posttraumatic cases (n = 27/31; 87.1%) as compared with postoperative cases (n = 4/9; 44.4%). Of the 43 patients, only 9 patients (20.9%) achieved a VA ≥ 20/200 on final follow-up. Four out of twelve patients (33.3%), with fungus as one of the isolates, had a VA ≥ 20/200.ConclusionsAlthough polymicrobial infection in endophthalmitis is uncommon, it is generally associated with poor visual acuity outcomes especially in eyes with open-globe injuries. Coinfection with Gram-negative bacteria or fungi was associated with most unfavorable visual outcome.

Polymicrobial chronic endophthalmitis diagnosed by culture and molecular technique

“…Large studies have reported variable prevalence of polymicrobial infection (3.88-20.4% of culture proven endophthalmitis) from different parts of the world including India. [2][3][4][5] However, the actual number is likely to be higher as all these studies have recruited only culture proven cases. Besides, they have looked at only cases of acute-onset endophthalmitis.…”

Eye Coinfections

“…Although eye coinfections are not the subject of epidemiological surveillance, they are not as rare as previously thought and can represent 3.88 % of endophthalmitis cases, for example, and more than 50 % in some series of patients with conjunctivitis reported in the literature [6,7].…”

“…In the case of fungi, when they are present with bacteria, only small changes are observed [3]. The clinical spectrum of keratitis can change when there is a coinfection between bacteria and Candida spp., mainly occurs; however, when endophthalmitis involves coinfection of a fungus and Gram-negative bacteria, the result is more unfavorable [6].…”

Targeted treatment for bacterial infections: prospects for pathogen-specific antibiotics coupled with rapid diagnostics

“…184 Identification of polymicrobial infections would also be crucial to prevent treatment failure due to the second, untreated pathogen. 187,188 Many newer diagnostic methods are designed around technologies that simply do not work well when multiple species are present in the sample. 189,190 False negatives with rarer pathogens resulting from molecular diagnostics that only test for the most common causes of infection is an additional concern, although this certainly applies to treating with any antibiotic regardless of spectrum.…”