Prospective study of risk factors for conjunctival bacterial contamination in patients undergoing intraocular surgery

PURPOSE

To determine whether a patient's age, gender, local or systemic risk factors affect the rate of preoperative bacterial contamination.

METHODS

Consecutive 1,474 patients undergoing intraocular surgery were enrolled in this prospective masked study. Past medical history was noted and examinations were performed. The patients were divided into four groups: a control group (without local or systemic risk factors), those with local risk factors (chronic use of topical medications, contact lens wear, blepharitis, chronic eyelid or conjunctival inflammation), those with systemic risk factors (immunosuppression, diabetes, autoimmune conditions, and asthma), and those with both. Conjunctival cultures were obtained before surgery.

RESULTS

Among the 1,474 patients, 914 bacteria were isolated from 214 (14.9%) patients. Advanced age was associated with a higher rate of positive conjunctival cultures (p<0.005). No statistical difference was found with regard to gender (p=0.7173). Among the 282 patients in the control group, 14 (5%) had a positive conjunctival culture. Compared to the control group, positive conjunctival cultures were found in 118 out of 503 patients (23.5%) with local risk factors (p<0.0001), 65 out of 545 patients (11.9%) with systemic risk factors (p=0.0019), and 22 out of 144 (15.3%) with both (p=0.0006). Two patients developed postoperative endophthalmitis (0.14%), one with both local risk and systemic factors and the other with a systemic risk factor.

CONCLUSIONS

Patients with local or systemic risk factors or advanced age were found to have a higher rate of bacterial conjunctival contamination before intraocular surgery.

One-day application of topical moxifloxacin 0.5% to select for fluoroquinolone-resistant coagulase-negative Staphylococcus

PURPOSE

To compare selection for fluoroquinolone-resistant bacteria between 1-day and 3-day application of topical moxifloxacin 0.5%.

SETTING

Department of Ophthalmology, Stanford University, Stanford, California, USA.

METHODS

After investigative review board approval, patients scheduled for ocular surgery were randomized to receive topical moxifloxacin 0.5% drops 4 times a day for 1 day or 3 days preoperatively. Conjunctival cultures were obtained at baseline and after antibiotic application. Bacteria were identified and tested for resistance to a battery of antibiotic agents using the Kirby-Bauer disk-diffusion method. The differences in resistance distributions for the most commonly isolated bacteria between baseline (T0) and after antibiotic administration (T1) were compared between the 2 treatment groups.

RESULTS

Coagulase-negative Staphylococcus (CNS) were the most common bacteria isolated at T0 and T1. At T0, the proportion of CNS isolated in the 1-day group (n = 63) that was resistant to fluoroquinolones ranged from 4% to 22% depending on the antibiotic agent tested. After 1-day treatment with moxifloxacin, the percentage of resistant bacteria increased significantly (range 13% to 67%) for all fluoroquinolones except gatifloxacin (P<.05). Resistance to gentamicin and tobramycin also increased significantly. However, patients treated for 3 days (n = 57) showed no differences in bacterial resistance rates to any antibiotic agent tested.

CONCLUSION

Prophylactic topical moxifloxacin 0.5% treatment starting 1 day before ocular surgery resulted in a significant increase in fluoroquinolone-resistant bacteria, while a 3-day antibiotic regimen did not select for resistant organisms.

Prospective randomized comparison of 1-day and 3-day application of topical 0.5% moxifloxacin in eliminating preoperative conjunctival bacteria

PURPOSE

Compare the efficacy of a 1-day versus 3-day application of topical 0.5% moxifloxacin in reducing preoperative conjunctival bacteria.

METHODS

Following IRB approval, patients (n = 144) scheduled for ocular surgery between 2004 and 2005 were recruited and randomized to receive topical 0.5% moxifloxacin drops four times a day for either 1 day (n = 63) or 3 days (n = 57) prior to surgery. Conjunctival cultures were obtained at baseline (T0), after application of antibiotic (T1), following povidone-iodine and additional antibiotic applications immediately before surgery (T2), and after surgery (T3). Cultures were inoculated onto blood and chocolate agar plates and in thioglycolate broth, and then incubated at 37 degrees C for 10 days. Bacterial growth were isolated, identified, quantified, and compared.

RESULTS

There were similar (P = 0.8435) rates of patients with positive thioglycolate cultures between the 1-day (79.37%) and 3-day groups (82.46%) at T0. At T1, T2, and T3, the number of eyes with positive cultures were again similar (1 day, 3 days, P value [T1: 34.9%, 35.1%, P = 0.8631; T2: 14.3%, 7%, P = 0.3245; T3: 7.9%, 3.5%, P = 0.5199]). No significant differences were found between the colony-forming units (CFU) of bacteria on solid agar media in 1-day and 3-day groups at any of the time points studied (P values: 0.1-0.8). Coagulase-negative Staphylococcus was the most commonly isolated (73.3% at baseline).

CONCLUSIONS

In patients undergoing intraocular anterior segment surgery, 1-day and 3-day applications of topical 0.5% moxifloxacin appear to have similar efficacy in reducing perioperative conjunctival bacteria.

Bioactive interpenetrating polymer network hydrogels that support corneal epithelial wound healing

The development and characterization of collagen-coupled poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) interpenetrating polymer network hydrogels is described. Quantitative amino acid analysis and FITC-labeling of collagen were used to determine the amount and distribution of collagen on the surface of the hydrogels. The bioactivity of the coupled collagen was detected by a conformation-specific antibody and was found to vary with the concentration of collagen reacted to the photochemically functionalized hydrogel surfaces. A wound healing assay based on an organ culture model demonstrated that this bioactive surface supports epithelial wound closure over the hydrogel but at a decreased rate relative to sham wounds. Implantation of the hydrogel into the corneas of live rabbits demonstrated that epithelial cell migration is supported by the material, although the rate of migration and morphology of the epithelium were not normal. The results from the study will be used as a guide toward the optimization of bioactive hydrogels with promise in corneal implant applications such as a corneal onlay and an artificial cornea.

A prospective randomized evaluation of topical gatifloxacin on conjunctival flora in patients undergoing intravitreal injections

PURPOSE

We sought to assess the efficacy of 3-day topical gatifloxacin use in combination with povidone-iodine (PVI) versus PVI alone in eliminating conjunctival bacterial flora in patients scheduled to undergo intravitreal (IVT) injection.

DESIGN

Prospective, randomized single-blind clinical trial.

PARTICIPANTS

We included 129 patients scheduled to undergo 273 IVT injections at California Vitreoretinal Center at Stanford University.

METHODS

Study patients were randomized to self-administration of gatifloxacin drops for 3 days before injection, or no pretreatment antibiotics. Cultures were collected from the bulbar conjunctiva at the injection site and at the corresponding location in the fellow eye before PVI preparation. After topical PVI treatment and immediately before injection, a third culture was obtained at the injection site. Additionally, the injection needle was also cultured after the procedure.

MAIN OUTCOME MEASURES

Incidence of positive bacterial samples collected from injection site conjunctiva and injection needles.

RESULTS

Three-day gatifloxacin use resulted in a significantly lower rate of SeptiChek (Becton Dickinson, Franklin Lakes, NJ) positive cultures compared with untreated controls (21% vs 48% respectively, P = 0.005). After topical PVI, the rate of positive bacterial cultures in gatifloxacin-treated and control eyes were similar (8% and 4%, respectively; P = 0.324).

CONCLUSIONS

Although 3-day topical gatifloxacin use is effective in reducing the frequency of conjunctival bacterial growth relative to untreated eyes, antibiotic use confers no additional benefit in combination with PVI than eyes receiving PVI alone. This supports that topical PVI is an effective preinjection monotherapy for infection prophylaxis in the setting of IVT injections.

A prospective study determining the efficacy of topical 0.5% levofloxacin on bacterial flora of patients with chronic blepharoconjunctivitis

BACKGROUND

To determine the efficacy of conjunctival bacterial eradication following a 1-day, 3-day and 7-day application of topical 0.5% levofloxacin, with and without eyelid scrub, in patients with chronic blepharoconjunctivitis (CBC).

METHODS

Patients with CBC (n = 60) were prospectively randomized to three groups (n = 20 in each group): no antibiotic treatment, topical levofloxacin four times per day in both eyes, and eyelid scrub in addition to topical levovofloxacin four times a day in both eyes. Patients without CBC (n = 40) were enrolled as the negative control group. Cultures of the conjunctiva were obtained from both eyes at baseline, 1 day, 3 days, and 7 days following treatment.

RESULTS

The most common bacteria isolated for all groups at baseline were coagulase-negative Staphylococcus. Eight patients did not complete the study. The remaining 52 patients with CBC had a significantly higher rate of positive thioglycolate broth cultures (94%) compared to a 58% positive culture rate in patient without CBC (P < 0.0001). Treatment with at least 3 days of topical antibiotic in patient with CBC resulted in a significant reduction (P < 0.05) in the number of thioglycolate positive cultures (<or= 60%) compared to non-treated eyes (>or= 88%). Following a minimum of a 1-day application of antibiotic, the median colony-forming unit was 0-1 compared to 3-8 for eyes without antibiotic treatment (P < 0.05). Scrubbing of the eyelids did not provide further benefit compared to antibiotic treatment alone.

CONCLUSIONS

CBC eyes have a significantly higher number of positive cultures than eyes without CBC. The application of topical 0.5% levofloxacin for at least 3 days provided a significant reduction in the number of positive cultures as well as the number of bacteria harbored on the conjunctival surface.

Prospective comparison of topical moxifloxacin in eliminating conjunctival bacterial flora following a one-day or one-hour application

PURPOSE

The aim of this study was to compare the efficacy of a 1-hour(h) versus 1-day application of topical moxifloxacin in eliminating conjunctival bacterial flora.

METHODS

In this prospective, nonrandomized, controlled trial, the surgical eyes of 60 patients scheduled for intraocular surgery received topical moxifloxacin four times a day, starting 1 day prior to surgery and three additional applications at 5-minute intervals 1 h before surgery. The nonsurgical eye of each patient only received three applications of the same antibiotic at 5-minute intervals 1 h before surgery. Conjunctival cultures were obtained at baseline and after antibiotic application.

RESULTS

Prior to antibiotic application, 80% of surgical eyes and 70% of nonsurgical eyes had positive cultures. Following the 1-day application, significantly fewer eyes (40%) had positive cultures (P < 0.0001), with a further reduction to 32% with three additional doses 1 h prior to surgery. In the nonsurgical eye, the decrease in the percentage of positive cultures, from 55% to 53% following the three applications 1 h prior to surgery, was not significant (P > 0.9999). The 1-day application was associated with significantly fewer positive cultures, compared to the 1-h group (P = 0.0267).

CONCLUSIONS

The one-day application of moxifloxacin resulted in significantly fewer positive conjunctival cultures, compared with a 1-h application.

Bacterial contamination of ocular surface and needles in patients undergoing intravitreal injections

PURPOSE

To evaluate potential sources of bacterial contamination during intravitreal (IVT) injection procedures.

METHODS

Patients scheduled for IVT injection were asked to enroll in the study at the California Vitreoretinal Center (Menlo Park, CA) and the Vantage Eye Center (Salinas, CA) between October 2004 and April 2005. A total of 104 patients participated in the study, with a total of 118 IVT injection procedures performed on 107 eyes. Standard microbiological techniques were used to culture, identify, and quantify bacterial contamination of injection needles and the bulbar conjunctiva at the injection site in patients undergoing IVT injections. The main outcomes measured were type and quantity of bacterial isolates.

RESULTS

Two (2%) of 114 needles collected were contaminated with bacteria. The prevalence of bacterial contamination of the injection site on the bulbar conjunctiva was 43% before prophylaxis on the day of the injection with topical antibiotics and povidone-iodine, with a statistically significant reduction to 13% after prophylaxis (P < 0.0001). Coagulase-negative Staphylococcus, the most common bacterium isolated from the ocular surface, was isolated from both culture-positive needles.

CONCLUSIONS

IVT injection needles became contaminated with bacteria during the injection procedure. Although the contamination rate was low, this supports a mechanism of postinjection endophthalmitis in which there is direct inoculation of ocular surface flora into the vitreous cavity by the injection needle.

Development of hydrogel-based keratoprostheses: a materials perspective

Research and development of artificial corneas (keratoprostheses) in recent years have evolved from the use of rigid hydrophobic materials such as plastics and rubbers to hydrophilic, water-swollen hydrogels engineered to support not only peripheral tissue integration but also glucose diffusion and surface epithelialization. The advent of the AlphaCor core-and-skirt hydrogel keratoprosthesis has paved the way for a host of new approaches based on hydrogels and other soft materials that encompass a variety of materials preparation strategies, from synthetic homopolymers and copolymers to collagen-based bio-copolymers and, finally, interpenetrating polymer networks. Each approach represents a unique strategy toward the same goal: to develop a new hydrogel that mimics the important properties of natural donor corneas. We provide a critical review of these approaches from a materials perspective and discuss recent experimental results. While formidable technical hurdles still need to be overcome, the rapid progress that has been made by investigators with these approaches is indicative that a synthetic donor cornea capable of surface epithelialization is now closer to becoming a clinical reality.

Glucose-permeable interpenetrating polymer network hydrogels for corneal implant applications: a pilot study

Epithelialization of a keratoprosthesis requires that the implant material be sufficiently permeable to glucose. We have developed a poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) interpenetrating polymer network (IPN) hydrogel that can provide adequate passage of glucose from the aqueous humor to the epithelium in vivo. A series of PEG/PAA IPNs with varying PEG macromonomer molecular weights were synthesized and evaluated through swelling studies to determine their water content and diffusion experiments to assess their permeability to glucose. One of the PEG/PAA hydrogels prepared in this study had a glucose diffusion coefficient nearly identical to that of the human cornea (approximately 2.5 x 10(-6) cm(2)/sec). When implanted intrastromally in rabbit corneas, this hydrogel was retained and well-tolerated in 9 out of 10 cases for a period of 14 days. The retained hydrogels stayed optically clear and the epithelium remained intact and multilayered, indicating that the material facilitated glucose transport from the aqueous humor to the anterior part of the eye. The results from these experiments indicate that PEG/PAA hydrogels are promising candidates for corneal implant applications such as keratoprostheses and intracorneal lenses, and that the PEG/PAA IPN system in general is useful for creating permeable substrates for ophthalmic and other biomedical applications.

Design and fabrication of an artificial cornea based on a photolithographically patterned hydrogel construct

We describe the design and fabrication of an artificial cornea based on a photolithographically patterned hydrogel construct, and demonstrate the adhesion of corneal epithelial and fibroblast cells to its central and peripheral components, respectively. The design consists of a central "core" optical component and a peripheral tissue-integrable "skirt." The core is composed of a poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) double-network with high strength, high water content, and collagen type I tethered to its surface. Interpenetrating the periphery of the core is a microperforated, but resilient poly(hydroxyethyl acrylate) (PHEA) hydrogel skirt that is also surface-modified with collagen type I. The well-defined microperforations in the peripheral component were created by photolithography using a mask with radially arranged chrome discs. Surface modification of both the core and skirt elements was accomplished through the use of a photoreactive, heterobifunctional crosslinker. Primary corneal epithelial cells were cultured onto modified and unmodified PEG/PAA hydrogels to evaluate whether the central optic material could support epithelialization. Primary corneal fibroblasts were seeded onto the PHEA hydrogels to evaluate whether the peripheral skirt material could support the adhesion of corneal stromal cells. Cell growth in both cases was shown to be contingent on the covalent tethering of collagen. Successful demonstration of cell growth on the two engineered components was followed by fabrication of core-skirt constructs in which the central optic and peripheral skirt were synthesized in sequence and joined by an interpenetrating diffusion zone.

Progress in the development of interpenetrating polymer network hydrogels

Interpenetrating polymer networks (IPNs) have been the subject of extensive study since their advent in the 1960s. Hydrogel IPN systems have garnered significant attention in the last two decades due to their usefulness in biomedical applications. Of particular interest are the mechanical enhancements observed in "double network" IPN systems which exhibit nonlinear increases in fracture properties despite being composed of otherwise weak polymers. We have built upon pioneering work in this field as well as in responsive IPN systems to develop an IPN system based on end-linked poly-(ethylene glycol) (PEG) and loosely crosslinked poly(acrylic acid) (PAA) with hydrogen bond-reinforced strain-hardening behavior in water and high initial Young's moduli under physiologic buffer conditions through osmotically induced pre-stress. Uniaxial tensile tests and equilibrium swelling measurements were used to study PEG/PAA IPN hydrogels having second networks prepared with varying crosslinking and photoinitiator content, pH, solids content, and comonomers. Studies involving the addition of non-ionic comonomers and neutralization of the second network showed that template polymerization appears to be important in the formation of mechanically enhanced IPNs.

A prospective randomized study to determine the efficacy of preoperative topical levofloxacin in reducing conjunctival bacterial flora

PURPOSE

To compare the efficacy of topical levofloxacin in combination with povidone-iodine irrigation vs povidone-iodine (PVI) alone in reducing conjunctival bacteria.

DESIGN

Prospective, randomized, controlled trial.

METHODS

One hundred and forty eyes of 140 patients scheduled to undergo intraocular surgery eyes were randomized to either group 1 or 2 (70 each). Whereas group 1 eyes had no prophylactic antibiotic, eyes in group 2 received topical treatment with one drop of 0.5% levofloxacin four times on the day before surgery. Both groups underwent irrigation of the fornices with 1% PVI. Conjunctival swabs were inoculated on solid and broth culture media to determine bacterial growth.

RESULTS

Of 132 eyes evaluated, baseline culture analysis in thioglycolate demonstrated positive culture results in 55 (84.6%) of 65 eyes from group 1, similar to 55 (82.1%) of 67 eyes in group 2 (P = .697). Before surgery, 57 (87.7%) of 65 eyes in group 1 had positive culture results, compared with 50 (74.6%) of 67 eyes in group 2 (P = .055). After irrigation with PVI, 20 (30.8 %) of 65 eyes in group 1 had positive culture results, compared with only eight (11.9%) of 67 eyes in group 2 (P = .008). After surgery, 15 (23.1%) of 65 eyes in group 1 and six (9.0%) of 67 eyes in group 2 had positive culture results (P = .027).

CONCLUSIONS

Our study shows an enhanced effect of using topical levofloxacin in combination with PVI irrigation to reduce conjunctival bacteria in patients undergoing intraocular surgery.

Aspergillus fumigatus keratitis following laser in situ keratomileusis

A 31-year-old woman developed pain, decreased vision, and a corneal flap infiltrate 4 days following laser in situ keratomileusis (LASIK). Treatment with topical antibiotic agents did not improve the symptoms. Approximately 2 weeks after surgery, the patient was referred to Stanford University, with 20/400 visual acuity in the left eye and a stromal infiltrate posterior to the flap. Cultures demonstrated Aspergillus fumigatus sensitive to voriconazole. The corneal ulcer progressed despite aggressive antifungal treatment, requiring amputation of the corneal flap and daily debridement. The infiltrate resolved in response to topical voriconazole, natamycin, and oral voriconazole. Aspergillus fumigatus keratitis is a rare but serious complication of LASIK surgery. The infection was successfully treated with flap amputation and daily debridement in addition to antifungal therapy.

Prospective randomized comparison of 1-day versus 3-day application of topical levofloxacin in eliminating conjunctival flora

PURPOSE

To compare efficacy of a 1-day versus 3-day application of topical levofloxacin in reducing ocular surface bacteria.

METHODS

In this prospective randomized controlled trial, 100 volunteer patients (50 per group) were assigned to receive topical 0.5% levofloxacin four times daily for 1 day or 3 days. Conjunctival cultures were obtained prior to (T0) and after the application of antibiotics (T1). Additionally, all patients received topical levofloxacin at 5-minute intervals for three applications (T2), followed by two drops of topical 5% povidone-iodine (T3). Conjunctival cultures were obtained at timepoints T2 and T3.

RESULTS

A 1-day application of topical levofloxacin significantly reduced (p = 0.0004) the number of eyes with positive conjunctival cultures from 41 eyes (82%) to 23 eyes (46%). Similarly, a 3-day application significantly reduced (p = 0.0001) the positive culture rate from 37 eyes (74%) to 17 eyes (34%). Two drops of povidone-iodine further reduced the positive culture rate for both groups to 20% (10 eyes for each group). There was no significant difference in positive culture rate between the 1-day and 3-day groups at T0 (p = 0.4689), T1 (p = 0.3074), T2 (p = 0.6706), or T3 (p = 1.000).

CONCLUSIONS

The application of topical 0.5% levofloxacin for 1 or 3 days significantly reduced the number of eyes with positive conjunctival cultures. The addition of 5% povidone-iodine further eliminated bacteria from the conjunctiva. The application of levofloxacin for 1 day appears to be as effective as a 3-day application.

Endophthalmitis prophylaxis

The prevalence of postoperative endophthalmitis following cataract surgery appears to be increasing with the popularity of clear cornea incision. As a result, endophthalmitis prophylaxis will play and increasingly important role as the number of clear cornea cataract surgeries increases. In this article, the authors examine and critically evaluate techniques used to prevent endophthalmitis including proper preoperative patient preparation, application of povidone-iodine, and use of broad-spectrum antibiotics (topical, intracameral, and subconjunctival injection).

Wirksamkeit neuer Fluorchinolone gegenüber der bakteriellen Normalflora der Bindehaut

BACKGROUND

Our aim was to determine the antibiotic susceptibility of the preoperative conjunctival bacterial flora against 25 commonly used antibiotics, especially the new fluoroquinolones levofloxacin, gatifloxacin, and moxifloxacin.

PATIENTS AND METHODS

The Kirby-Bauer disk-diffusion technique was used to test for the in vitro antibiotic susceptibility of conjunctival bacterial strains isolated from 160 patients (median=74 years, mean=71 years) undergoing cataract surgery at the Department of Ophthalmology, Stanford University, CA, USA.

RESULTS

Among the 256 bacteria isolated, 201 (79%) were coagulase-negative staphylococci (CNS), 26 Staphylococcus aureus, 15 Streptococcus group D and 14 gram-negative rods. A total of 100 of these 256 strains (39%) were classified as multiresitant (resistant to>or=five antibiotics). The resistance rate (RR) of commonly used antibiotics for all CNS was: gatifloxacin=moxifloxacin<gentamycin=tobramycin=levofloxacin=neomycin<ciprofloxacin=ofloxacin<erythromycin. The RR for S. aureus and the gram-negative rods was low and insignificant in comparison to the other antibiotics tested. None of the Streptococcus group D were resistant to gatifloxacin, levofloxacin, or moxifloxacin, however, they were highly resistant (RR over 30%) to the other antibiotics. Some 50% of the bacteria were resistant to erythromycin.

CONCLUSION

Newer generation fluoroquinolones provide excellent efficacy against coagulase-negative staphylococci and Streptococcus group D despite a high number of multiresitant bacteria.

Glucose Permeability of Human, Bovine, and Porcine Corneas in vitro

PURPOSE

To measure glucose flux across human, bovine, and porcine corneas and to determine the diffusion coefficient of each type of cornea.

METHODS

Diffusion of glucose across human (n = 8), bovine (n = 7), and pig corneas (n = 8) was measured using a modified blind well chamber apparatus (Boyden chamber). Dialysis membranes (n = 7) and nonporous Mylar membranes (n = 7) were used as positive and negative controls, respectively. Glucose concentrations were measured at 30-min intervals with a commercially available glucose meter.

RESULTS

The diffusion of glucose through corneas in vitro was calculated by a simple Fickian diffusion model. The diffusion coefficient of glucose is highest for the human cornea (D(HC) = 3.0 +/- 0.2 x 10(-6) cm(2)/s) followed by porcine corneas (D(PC) = 1.8 +/- 0.6 x 10(-6) cm(2)/s) and bovine corneas (D(BC) = 1.6 +/- 0.1 x 10(-6) cm(2)/s) (p < 0.05). The diffusion coefficients of all tested corneas were significantly higher (p < 0.05) than that of dialysis membrane (D(DM) = 3.4 +/- 0.2 x 10(-7) cm(2)/s).

CONCLUSION

The glucose diffusion coefficients of human, bovine, and porcine corneas are on the order of 10(-6). Human corneas have higher permeability to glucose than either porcine or bovine corneas.

Prospective randomized study determining whether a 3-day application of ofloxacin results in the selection of fluoroquinolone-resistant coagulase-negative Staphylococcus

PURPOSE

To determine whether a 3-day application of ofloxacin results in the selection of fluoroquinolone-resistant conjunctival coagulase-negative Staphylococcus.

DESIGN

Prospective randomized trial.

METHODS

Patients scheduled for ocular surgery were randomized to a control (89 eyes) or study group (70 eyes). The study group received topical ofloxacin (0.3%) four times a day for 3 days. Conjunctival cultures were obtained at baseline (T0) and after 3 days of ofloxacin (T1). Cultures were also obtained at T0 and T1 for the control group, but these eyes did not receive an antibiotic. Bacteria isolated were identified and antibiotic susceptibility was determined.

RESULTS

At T0, 53 out of 89 patients (60%) in the control and 48 out of 70 patients (69%) in the study group harbored coagulase-negative Staphylococcus. Among these coagulase-negative Staphylococcus, 12 out of 53 in the control and 11 out of 48 in the study group were resistant to ofloxacin (p>0.9999). At T1, significantly fewer coagulase-negative Staphylococcus (p=0.0003) were isolated from the study group (18 coagulase-negative Staphylococcus), compared the control group (48 coagulase-negative Staphylococcus). Of these, 5 out of 17 coagulase-negative Staphylococcus in the study group and 9 out of 48 coagulase-negative Staphylococcus in the control group were resistant to ofloxacin (p=0.5649). There was no significant difference in the number of coagulase-negative Staphylococcus resistant to ciprofloxacin or norfloxacin in the study group compared to the control group at T1.

CONCLUSIONS

Ofloxacin given four times a day for 3 days does not select out for conjunctival fluoroquinolone-resistant coagulase-negative Staphylococcus.

Clinical results of topical fluconazole for the treatment of filamentous fungal keratitis

BACKGROUND

Fungal keratitis is a rare but serious condition that may result in loss of vision. The potentially poor prognosis might be due to a delay in diagnosis and/or to limited treatment options. The aim of this study is to evaluate the clinical outcome of patients treated with topical fluconazole 0.2% for the treatment of filamentous fungal keratitis.

METHODS

Retrospective case series. A chart review of all patients evaluated at the Ophthalmology Department of the Hospital de Clínicas in Paraguay from January 1997 to December 2000 identified 25 cases of fungal keratitis. Among these cases, one patient discontinued the treatment and another received amphotericin as the first line drug, resulting in 23 cases available for data analysis. Twelve patients were treated with topical fluconazole 0.2% alone (Group I) and 11 patients received a combination of topical fluconazole 0.2% and oral ketoconazole 200 mg twice daily (Group II).

RESULTS

Sixteen of 23 cases showed resolution of the keratitis, 9/12 (75%) in Group I and 7/11 (64%) in Group II. Seven patients (30%) did not respond to medical treatment and required a surgical procedure to preserve eye integrity. Superficial and small ulcers have a significantly better prognosis than do lrge and deep ulcers. Concomitant oral ketoconazole (400 mg/day) did not improve the clinical results.

CONCLUSIONS

Our findings of study suggest that topical fluconazole 0.2% is a safe and effective antifungal drug for the management of filamentous mycotic keratitis, particularly in cases that are not severe. The addition of oral ketoconazole to topical fluconazole did not improve the clinical outcome.

Normal ocular flora in newborns delivered in two hospital centers in Argentina and Paraguay

PURPOSE

To determine the spectrum of normal conjunctival flora in newborns in two hospital centers in North Argentina and Paraguay.

METHODS

In this prospective observational study, conjunctival specimens were obtained from the right eyes of newborns prior to the application of any topical medications. Culture samples were also obtained from the cervicovaginal secretions of the infants' mothers. All samples were directly inoculated into culture media and all growth were identified and quantified.

RESULTS

Among the 190 newborns studied, 126 were delivered vaginally and 64 via caesarean section (C-section). A total of 180 different bacterial strains were acquired from the vaginally delivered infants and 77 from the C-section group (P=0.078, Student's t-test). Conjunctival cultures obtained within one hour of birth showed that 85 out of 101 samples (84%) from both the vaginal and C-section group had positive cultures, compared to 84 out of 89 samples (94%) obtained more than 1 h after birth (P<0.001). Among the vaginally delivered newborns, the most common bacteria isolated were coagulase-negative Staphylococcus (in 69 samples, 38%), Propionibacterium spp (36, 20%) and Corynebacterium spp (29, 16%). In the CES, the most common isolates were coagulase-negative Staphylococcus (39, 51%), Propionibacterium spp (22, 29%) and Staphylococcus aureus (6, 8%). There was a significantly higher proportion of gram-positive rods (P=0.017) isolated from infants delivered vaginally (16%) than from those delivered by C-section (5%). No Neisseria gonorrhoeae were isolated in conjunctival samples. Among the 130 organisms isolated from cervicovaginal secretions in 81 out of 189 mothers, the most common organisms were Lactobacillus spp. (47%), Corynebacterium spp (21%), Gardnerella vaginalis (15%), and Candida spp (14%). No Neisseria gonorrhoeae or Chlamydia trachomatis were found in cervicovaginal samples.

CONCLUSION

The most common conjunctival bacteria in newborns delivered by either vaginal birth or C-section were coagulase-negative Staphylococcus. The proportion of positive conjunctival cultures was higher for infants delivered vaginally than for C-section delivery.