Etiology and epidemiological analysis of glaucoma-filtering bleb infections in a tertiary eye care hospital in south India

Abstract

Purpose:To evaluate the microbial etiology and associated risk factors among patients with blebitis following trabeculectomy.Materials and Methods:A retrospective analysis of all culture-proven blebitis was performed in patients who underwent trabeculectomy between January 2004 and December 2008. A standardized form was filled out for each patient, documenting sociodemographic features and information pertaining to risk factors. Swabbing of the infected bleb surface was performed for all suspected cases and further subjected to microbiological analysis.Results:A total of 23 patients with culture-proven blebitis were treated during the study period, with a mean age of 59.2 years (59.2 ± SD: 12.8; range, 30-81 years). Duration of onset was early (≤36 months) in six (26%) cases and late (> 36 months) in 17 (74%) cases with a range between 15 and 144 months (mean, 82.91 months; SD: 41.89). All 23 blebs were located superiorly and of which, 21 (91%) were microcystic avascular, 1 (4%) diffuse avascular, and 1 (4%) vascular flattened. The predominant risk factor identified was bleb leak (35%; 8 of 23) followed by thin bleb (22%; 5 of 23) and blepharitis (17%; 4 of 23). Bleb leaks (100%) were recorded only in patients with late onset (≥ 9 years) of infection (P< 0.001), while the incidence of ocular surface disease (100%) occurred early (≤3 years) (P< 0.001). Use of topical steroids was associated frequently with cases of thin blebs (80%; 4 of 5) (P< 0.001), while topical antibiotics showed bleb leaks (88%; 7 of 8) (P< 0.001). Coagulase-positive staphylococci were frequently recovered from blebitis with thin blebs (71%; 5 of 7) (P = 0.001), Coagulase-negative staphylococci (CoNS) with bleb leak (100%; 8 of 8) (P< 0.001), Corynebacterium with blepharitis (100%; 3 of 3) (P = 0.001), and Streptococci with releasable sutures (75%; 3 of 4) (P = 0.001).ConclusionBleb leak is the principal risk factor responsible for late-onset blebitis, while early-onset blebitis could be ascribed to ocular surface diseases. Streptococci were mainly responsible for early onset of infection, while the late onset was due to CoNS.

An unusual presentation of Pseudomonas aeruginosa blebitis following combined surgery

“…A study from a Tertiary Eye Care Hospital in South India revealed Streptococcus species as the predominant isolate from blebitis associated with releasable sutures. [ 1 ] The Gram-positive organisms like Staphylococcus and Streptococcus species were the most frequent organisms isolated from bleb associated infections followed by Gram-negative organisms. [ 1 2 ] P. aeruginosa has been reported to cause bleb associated endophthalmitis with fulminant presenting features and poor visual outcomes.…”

“…[ 1 ] The Gram-positive organisms like Staphylococcus and Streptococcus species were the most frequent organisms isolated from bleb associated infections followed by Gram-negative organisms. [ 1 2 ] P. aeruginosa has been reported to cause bleb associated endophthalmitis with fulminant presenting features and poor visual outcomes. [ 2 ] However, in our patient the infection was confined to the bleb with subtle signs and responded well to the antibiotics without any intraocular spread until the clearance of infection.…”

Trabeculectomy: Does It Have a Future?

“…Though TRAB success rates improved with the use of antifibrotics, the rates of delayed complication rates also increased parallelly, which again questioned the efficacy of TRAB as a standard glaucoma filtering surgery [15][16][17][18][27][28][29][30]. Belyea et al studied 385 eyes that underwent TRAB with antifibrotics (MMC and 5-FU) and found an incidence of late repetitive multifocal bleb leaks in 1.8% of the eyes [15].…”

“…The most common microbiological flora isolated from eyes with bleb-related infections includes Staphylococcus aureus, coagulase-negative staphylococci, Corynebacterium, and Haemophilus influenza [30].…”

Risk factors for bleb-related infection following trabeculectomy surgery: ocular surface findings—a case–control study

“…Inferior bleb placement has such a high risk of BRI4 that practice has changed to predominantly superiorly placed blebs. Other risk factors have been proposed including avascular blebs,5–7 bleb leak,8 9 blepharitis,10 5-fluorouracil,11 mitomycin C (MMC),2 12 limbus-based conjunctival flap,13 young age,4 diabetes,12 multiple filtration procedures9 and bleb manipulation 14…”