Adherence of bacteria to intraocular lenses: a prospective study.

Abstract

Aims-The study was designed to investigate the bacterial flora of the operating field during routine cataract surgery and the source of intraocular lens contamination during the surgery. Methods-The normal flora of the external eye and fornices of 17 patients undergoing selective cataract surgery was determined preoperatively. Swabs taken from the eyelid surface and lashes showed coagulase negative staphylococci (CNS) Material and methods Seventeen patients, nine male and eight female and without an active infectious disease, were entered into the study. Their ages ranged from 22 to 82 (mean 75) years. Preoperatively, three cotton wool swabs moistened in sterile saline were used to sample the skin of the upper lid, the base of the lashes, and the lower fomix of each patient. This was performed in the ward.Ocular preparation in theatre included cleaning of eyelids and lashes with chlorhexidine acetate BP 0.02%, 1/5000 dilution.Lashes were not cut and no prophylactic topical or systemic antibiotics were used. Patients were draped with disposable 3M perforated ophthalmic sheet 1064, and an adhesive barrier (3M steridrape 2035) was used to keep the lashes away from the field of the surgery.Thirty four sterile PMMA IOLs were used in the operating theatre (none of the IOLs were irrigated before use). After draping each patient, the upper lid was pulled up and a sterile IOL was touched onto the upper bulbar conjunctiva using a sterile forceps (total 17). It was then placed in a sterile container and immediately transported to the laboratory.Peroperatively, a control lens was placed on the drape within 2-4 cm of the edge of the steridrape (total 17). It was left in this position for the duration of surgery, 20 to 40 (mean 30 minutes). It was then placed in a sterile container and immediately sent to the laboratory.Two settle plates, one containing Columbia agar with 7% horse blood and the other containing Lab M fastidious anaerobic agar with 7% horse blood and nalidixic acid, were exposed in the operating theatre in each instance to monitor airborne contamination.Swabs and IOLs were cultured without delay, onto Columbia blood agar plates containing 7% horse blood, and onto Lab M fastidious anaerobic agar plates (FAA) containing 7% horse blood and nalidixic acid as a selective agent. Lenses were then dropped into cooked meat medium which was incubated at 370C.

Intracellularly Expressed TLR2s and TLR4s Contribution to an Immunosilent Environment at the Ocular Mucosal Epithelium

“…These commensal bacteria are generally regarded as beneficial microflora for the host because they can suppress pathogens by displacing them from a microbial niche or by secreting antimicrobial substances (36). Normal bacterial flora residing in the conjunctival sac or along the eyelid edge making contact with the corneal surface include coagulase negative staphylococci, P. acnes, and others (4,5). Commensal flora are also key to creating a symbiotic host-parasite interaction for the intestinal mucosa, especially in the large intestine.…”

“…However, physiological destruction of the ocular surface by trauma, immunodeficiencies, or routine contact lens wear increases the incidence of sightthreatening corneal infection caused by Pseudomonas aeruginosa and Staphylococcus aureus, the common causative pathogens (2,3). Residing in the conjunctival sac or eyelid edge of the ocular surface are normal bacterial flora, including coagulase negative staphylococci, Propionibacterium acnes, and other Gram-positive and -negative bacteria (4,5), but the corneal epithelium does not generally respond to such flora. In fact, in many cases, patients suffering from bacterial conjunctivitis show no signs of inflammation in their corneas.…”

Propionibacterium acnes and Staphylococcus epidermidis Isolated from Refractory Endodontic Lesions Are Opportunistic Pathogens

“…However, there is now considerable evidence that these organisms are increasingly isolated from human infections, and so their association with endodontic infections requires clarification. P. acnes, a non-spore-forming, Gram-positive anaerobic or aerotolerant rod, is a member of the resident microflora of the large intestine, conjunctiva, and external ear canal (10,15) and accounts for approximately half of the total skin microbiota (59), predominating over other pilosebaceous flora (16,39). Although traditionally considered to be relatively nonpathogenic, an increasing number of studies have implicated P. acnes as an opportunistic pathogen responsible for a wide range of infections and inflammatory conditions.…”

A model for the management of an atypical endophthalmitis outbreak

“…Most cases of POE are due to bacteria entering the eye at the time of surgery by means of surgical instruments, the irrigation fluid, or by contamination of the intraocular lens implant (IOL). [19][20][21][22] The incidence of positive cultures has been reported as 56% in the BOSU survey. 6 In many cases, the organisms involved are thought to originate from the periocular flora.…”