Anterior chamber bacterial contamination in cataract surgery

Abstract

BackgroundThe incidence of postoperative endophthalmitis has reduced during last several years to <0.01%; however, its associated complications continue to be devastating. Several sources of infection, including contamination by air, solutions, surgical instruments, intraocular lens, and wound leakage have been identified. The objective of this study was to evaluate the surgical technique, antibiotics, and asepsis that are used to reduce the risk of infection during cataract surgery.MethodsThis was a transversal prospective study, in which 64 cataract surgeries were evaluated from 32 patients, with 1 month recovery time; and cultures from preoperative and postoperative aspirates were analyzed. Two groups were established based on whether preoperative antibiotics were given or not. The analysis employed descriptive statistics.ResultsOf the 32 patients whose aspirates were obtained, three (9.37%) and 10 (31.25%) yielded positive cultures preoperative and postoperatively respectively. Staphylococcus species was the most common contaminating bacteria. The isolation of Staphylococcus species may indicate its potential as exogenous contaminant at time of wound closure. The cultures obtained from patients using preoperative antibiotics were positive for S. aureus in 10% (n = 2) of cases, and positive in 8.33% (n = 1) of cases not using antibiotics. The mean transoperative time with positive growth was 67 ± 17.8 minutes, and with negative growth was 76.3 ± 25.2 minutes. Two surgical techniques were evaluated: phacoemulsification and extracapsular extraction. The extracapsular technique showed a contamination rate of 33.33% (n = 8) compared to phacoemulsification with a rate of 25% (n = 2) (RR = 1.33).ConclusionsCommon contaminating microorganisms included the Staphylococcus species, which was isolated from the eyelids and ocular annexes at the time of wound closure. The isolation of microorganisms postoperatively could have been influenced by the surgical technique used, the surgical time, and the use of antibiotics.

Floral Differences of Conjunctiva in Patients with Renal Diseases

“…Despite the possibility of a protective role, S. epidermidis can cause ocular infections as an opportunistic pathogen. In healthy subjects, S. aureus was isolated from the conjunctival sac at a rate of 3 % to 15 % as temporary colonization [1,4] but not detected in the controls of the present study. It just was isolated in diabetic hemodialysis patients in all groups.…”

“…Some of the commensal flora may become resident in the conjunctiva and eyelids, potentially becoming pathogenic [2]. Ocular microbial flora is a significant source of ocular surface disorders and intraocular surgical contamination [3,4]. According to previous studies, bacterial contamination of aqueous humor samples taken from the anterior chamber in cataract surgery varies from 30 % to 50%.…”

Bacterial and Fungal Endophthalmitis

“…The likelihood that a patient will develop endophthalmitis depends on host factors, inoculum size, and pathogen factors. Bacteria that colonize the conjunctiva, such as coagulase-negative staphylococci, may be cultured from the aqueous at the end of surgery in approximately one-third of cataract surgery cases (11,12), yet only 1 in 500 to 1 in 1,000 cataract surgeries result in endophthalmitis, probably because of the immune system's ability to clear small inocula. The constant turnover of the aqueous every 100 min likely helps; communication with the vitreous, which does not regenerate, during cataract surgery increases the risk of postoperative endophthalmitis 6-fold (13).…”

The Pathogenesis of Staphylococcus aureus Eye Infections

“…Infection following cataract surgery is the most common form of endophthalmitis and it is commonly caused by coagulase-negative staphylococci although the more virulent infections involve S. aureus [ 8 , 118 , 119 ]. The incidence of endophthalmitis associated with cataract surgery is less than 0.01% [ 120 ]. Because endophthalmitis following surgery is typically caused by ocular surface organisms, the eyelid and surrounding area are treated with povidone iodine, which kills bacteria within seconds [ 121 ].…”