Conjunctival flora in anophthalmic patients: microbiological spectrum and antibiotic sensitivity.

AIM: To identify the spectrum and susceptibility pattern of isolated microorganisms from conjunctival flora of anophthalmic patients. METHODS: A cross-sectional clinical study including 60 patients with unilateral anophthalmia. Patients with use of antibiotic drops in their socket during the last month were also included. From each patient, three microbiological samples were taken from the lower conjunctival sac (healthy eye, pre-prosthesis, and retro-prosthesis space of socket). The 180 samples obtained were cultured. Isolates were identified and their antibiotic sensitivities were determined. RESULTS: A total of 251 isolates were recovered (62 isolates from healthy eye, 93 from pre-prosthesis, and 96 from retro-prosthesis space). The most common organism was Staphylococcus epidermidis, in both healthy eyes (64.5%) and sockets (45.5%). Altogether, coagulase-positive Staphylococci, Streptococci, and Gram-negative bacteria accounted for less than 15% of isolates in healthy eyes and more than 35% in sockets. Regarding the antibiotic sensitivities, there were no significant differences between isolates from sockets and healthy eyes. Nine patients recognized the use of self-prescribed antibiotic drops in their socket. In the healthy eyes of these subjects, Gram-positive microorganisms showed significantly greater resistance to aminoglycosides and tetracycline. CONCLUSION: Sockets of anophthalmic patients show a greater number of pathogens compared to healthy eyes. The use of antibiotic drops in the socket promotes a resistant flora not only in the socket but also in the healthy eye. Quinolones and macrolides may be better therapeutic options than aminoglycosides for treating conjunctivitis of anophthalmic sockets, since these antibiotics are less active against Staphylococcus epidermidis.

In vitro adherence of conjunctival bacteria to different oculoplastic materials.

AIM: To investigate the resistance to bacterial adhesion of materials used in oculoplastic surgery, particularly materials used in the manufacture of orbital implants. METHODS: Seven organisms of conjunctival flora (two strains of Staphylococcus epidermidis and one strain each of Staphylococcus aureus, Staphylococcus hominis, Corynebacterium amycolatum, Acinetobacter calcoaceticus, and Serratia marcescens) were selected. A lactic acid bacterium (Lactobacillus rhamnosus) was also included as positive control because of its well-known adhesion ability. Eight materials used to make oculoplastic prostheses were selected (glass, steel, polytetrafluoroethylene, polymethylmethacrylate, silicone from orbital implants, commercial silicone, porous polyethylene, and semi-smooth polyethylene). Materials surfaces and biofilms developed by strains were observed by scanning electron microscopy. Kinetics of growth and adhesion of bacterial strains were determined by spectrophotometry. Each strain was incubated in contact with plates of the different materials. After growth, attached bacteria were re-suspended and colony-forming units (CFUs) were counted. The number of CFUs per square millimetre of material was statistically analyzed. RESULTS: A mature biofilm was observed in studied strains except Staphylococcus hominis, which simply produced a microcolony. Materials showed a smooth surface on the microbial scale, although steel exhibited 1.0-µm-diameter grooves. Most organisms showed significant differences in adhesion according to the material. There were also significant differences in the total number of CFUs per square millimetre from each material (P=0.044). CFU counts were significantly higher in porous polyethylene than in silicone from orbital implants (P=0.038). CONCLUSION: Silicone orbital implants can resist microbial colonization better than porous polyethylene implants.

Study of conjunctival flora in anophthalmic patients: influence on the comfort of the socket.

PURPOSE: To investigate the relationship between conjunctival flora and comfort of the socket in anophthalmic patients. METHODS: A cross-sectional clinical study including 60 patients with unilateral anophthalmia who wear a prosthetic eye. From each patient three microbiological samples were taken from the lower conjunctival sac (healthy eye, pre-prosthesis, and retro-prosthesis space of socket). The 180 samples obtained were cultured. Samples from a randomized subgroup of 29 patients were measured by spectrophotometry at 540 nm after 48 h of growth, to determine their microbial density (MD). The grade of comfort of the socket (GCS) of each patient was established by a questionnaire. Epidemiological and clinical data of the anophthalmic socket and artificial eye care of each patient were also collected. RESULTS: MD decreased in healthy eyes (0.213 ± 0.201, P = 0.004) compared with the pre-prosthesis (0.402 ± 0.323) and retro-prosthesis (0.438 ± 0.268) samples. Pre-prosthesis MD correlated with retro-prosthesis MD (R = 0.401, P = 0.031) and healthy eye MD (R = 0.482, P = 0.008), and it was also related to poor GCS (P = 0.017). Aerobic Gram-negative bacteria in retro-prosthesis samples of patients with poor GCS was higher than in patients with good or fair GCS (P = 0.008). In the same samples, coagulase-negative staphylococci proportion (excluding S. epidermidis) increased in patients with good GCS (P = 0.030). CONCLUSIONS: Socket microflora is related to GCS. Increased pathogenic flora, especially Gram-negative bacteria, and high MD are related to discomfort, while coagulase-negative staphylococci (other than S. epidermidis) are associated with comfort.

Refractory pyoderma gangrenosum of the orbit and the lacrimal sac.

Pyoderma gangrenosum (PG) is a rare, idiopathic, necrotizing, and non-infectious ulcerating skin disease included among the neutrophilic dermatoses. It rarely affects the eye, orbit, and/or ocular adnexa. We describe one case of PG affecting both orbits and the lacrimal sac in a patient with Crohn's disease.