Darlene Miller

Shifting trends in bacterial keratitis in South Florida and emerging resistance to fluoroquinolones

OBJECTIVE To study the distribution, current trends, and patterns of resistance to antimicrobial agents of bacterial keratitis isolates in South Florida. DESIGN Retrospective, observational, case series. PARTICIPANTS The microbiology records of all patients with bacterial keratitis seeking treatment at the Bascom Palmer Eye Institute from January 1, 1990 through December 31, 1998 were reviewed. MAIN OUTCOME MEASURES In vitro laboratory minimum inhibitory concentration testing of the corneal isolates to the fluoroquinolones (ofloxacin and ciprofloxacin) and to the aminoglycosides (tobramycin and gentamicin) was performed using the Vitek (Automatic Microbial System Biomerieux Vitek, Inc., Hazelwood, Missouri) method. RESULTS During this 9-year period, 2920 consecutive corneal cultures were obtained, and a pathogen was recovered in 1468 cultures (50%). The number of corneal ulcers scraped, positive cultures, recovered bacterial isolates, and ratio of gram-positive to gram-negative isolates per year remained approximately equal throughout the study period. Staphylococcus aureus and Pseudomonas aeruginosa represented 19.4% and 25.7%, respectively, of the total bacterial isolates during this period. However, we documented a gradual increase in the number of S. aureus keratitis isolates (29% of gram-positive organisms in 1990 versus 48% in 1998, P = 0.01) coupled with a decrease in the number of P. aeruginosa isolates (54% of gram-negative organisms in 1990 versus 46% in 1998). A decrease in the incidence of contact lens-associated keratitis and P. aeruginosa isolates in this group of patients was documented. Serratia marcescens and P. aeruginosa were most commonly isolated in contact lens-associated keratitis (18% each). There was increasing laboratory resistance of S. aureus keratitis isolates to the fluoroquinolones (11% in 1990 to 28% in 1998), but resistance patterns to the aminoglycosides remained unchanged. There was a three-fold increase in the percentage of resistant S. aureus isolates to fluoroquinolones between 1990 and 1994 and between 1995 and 1998. Both fluoroquinolones and aminoglycosides exhibited low in vitro effectiveness against P. aeruginosa throughout the study period. CONCLUSIONS The increased recovery of S. aureus keratitis isolates and decreased laboratory effectiveness against fluoroquinolones to these pathogens present an important therapeutic challenge.

The changing spectrum of fungal keratitis in south Florida.

PURPOSE To review the clinical experience with fungal keratitis in south Florida over a 10-year period. METHODS One hundred twenty-five cases of fungal keratitis were identified in the microbiology laboratory records between January 1982 and January 1992. The medical record of each patient was reviewed. RESULTS The most commonly associated risk factor was trauma (44%). Fungal keratitis developed in five patients using extended wear contact lenses and one patient wearing a therapeutic bandage contact lens. Clinical features included irregular, feathery margins (62%), a dry, rough texture (47%), and satellite lesions (41%). An initial positive culture was obtained in 90% of patients, with a majority of cultures becoming positive within 48 hours. The Fusarium sp accounted for 62% of the isolates, with Fusarium oxysporum being the most commonly isolated organism. New fungal isolates include Candida parapsilosis, Aspergillus terreus, Candida tropicalis, and Trichosporon beigellii. Natamycin 5% suspension was the initial antifungal agent used for 91% of the patients, with an average duration of treatment of 38 days. Twenty-five patients were treated with oral ketoconazole for a median duration of 2 weeks, in addition to topical antifungal therapy. Thirty-four patients (27%) required a penetrating keratoplasty. Six patients had recurrence of fungal keratitis after penetrating keratoplasty. CONCLUSIONS Trauma, including contact lens wear, is the most commonly associated risk factor. The fungal organisms can be readily identified in culture. F. oxysporum is the most common organism, with new isolates identified. The mainstay of therapy is topical natamycin with the increasing use of imidazoles.

Endophthalmitis isolates and antibiotic sensitivities: a 6-year review of culture-proven cases

PURPOSE To investigate the spectrum of organisms causing culture-proven endophthalmitis and their susceptibilities to commonly used antimicrobial agents over 10 years. DESIGN Retrospective, noncomparative, consecutive case series. METHODS Medical records were reviewed of all cases with culture-proven endophthalmitis at a single institution from 2002 through 2011. The outcome measures included all intravitreal isolates identified as well as antibiotic susceptibilities. RESULTS A total of 448 organisms were isolated during the study interval. The most common organisms identified were Staphylococcus epidermidis in 30.1% (135/448), Streptococcus viridians group in 10.9% (49/448), Staphylococcus aureus in 7.8% (35/448), Candida albicans in 5.8% (26/443), other coagulase-negative staphylococci in 6.0% (27/448), Propionibacterium acnes in 4.7% (21/448), and Pseudomonas aeruginosa in 3.1% (14/448). Overall, 327 (72.9%) of 448 isolates were gram-positive organisms, 48 (10.7%) of 448 isolates were gram-negative organisms, 71 (15.8%) of 448 isolates were fungi, and 2 (0.4%) of 448 isolates were viruses. For gram-positive organisms, susceptibilities were the following: vancomycin, 100%; gentamicin, 88.0%; sulfamethoxazole/trimethoprim, 77.5%; levofloxacin, 58.5%; oxacillin, 54.7%; ciprofloxacin, 51.0%; gatifloxacin, 51.0%; and moxifloxacin, 47.0%. For gram-negative organisms, susceptibilities were the following: ceftazidime, 100%; levofloxacin, 100%; ciprofloxacin, 95.0%; tobramycin, 90.6%; gentamicin, 80.6%; and sulfamethoxazole/trimethoprim, 59.4%. CONCLUSIONS In the current study, no single antibiotic provided coverage for all of the microbes isolated from eyes with endophthalmitis. Combination therapy generally is the recommendation as the initial empiric treatment of suspected bacterial endophthalmitis. Appropriate history and characteristic clinical features may guide the use of initial antifungal agents.

Treatment strategies and visual acuity outcomes in chronic postoperative propionibacterium acnes endophthalmitis

PURPOSE To report the treatment strategies and visual acuity outcomes of chronic postoperative endophthalmitis caused by Propionibacterium acnes. DESIGN Retrospective noncomparative case series. PARTICIPANTS All patients presenting 8 or more weeks after cataract surgery with intraocular inflammation caused by culture-proven P. acnes infection and treated at two institutions from 1974 through 1996 were included. METHODS Patients underwent three different initial treatment strategies. The study did not have a defined treatment protocol, but all patients received intraocular antibiotics. Patients were not randomly assigned to the various treatment strategies. MAIN OUTCOME MEASURES Final visual acuity and effectiveness of various treatment procedures either as initial or follow-up therapy were assessed. RESULTS Using the 3 initial strategies, 36 patients were treated: (1) intraocular antibiotic injection alone (IOAB; n = 12); (2) pars plana vitrectomy and IOAB injection (PPV; n = 10); and (3) PPV with subtotal capsulectomy and IOAB injection (PPV-PC; n = 14). The number of patients with recurrent or persistent inflammation after one of the three initial treatment strategies were as follows: (1) IOAB alone, 12 (100%); (2) PPV, 5 (50%); and (3) PPV-PC, 2 (14%). None of the patients that underwent subsequent PPV, total capsular bag removal, IOAB injection, and either intraocular lens (IOL) exchange or removal had persistent or recurrent intraocular inflammation. Overall, final visual acuity was 20/40 or better in 18 patients (50%), and a total of 28 patients (78%) retained 20/400 or better vision. The mean follow-up after the last treatment was 2.9 years. CONCLUSIONS In this series of chronic P. acnes endophthalmitis, initial treatment with IOAB injection alone or vitrectomy without capsulectomy was associated with high rates of recurrent or persistent intraocular inflammation. Pars plana vitrectomy, partial capsulectomy, and IOAB injection without IOL exchange was usually successful on long-term follow-up. In patients with recurrent intraocular inflammation, pars plana vitrectomy, total capsular bag removal, IOAB injection, and IOL exchange or removal was a uniformly successful strategy. In contrast to other types of postoperative endophthalmitis, IOL exchange can be considered in these patients after total capsular bag removal.

An outbreak of streptococcus endophthalmitis after intravitreal injection of bevacizumab.

PURPOSE To report a series of patients with Streptococcus endophthalmitis after injection with intravitreal bevacizumab prepared by the same compounding pharmacy. DESIGN Noncomparative consecutive case series. METHODS Medical records and microbiology results of patients who presented with endophthalmitis after injection with intravitreal bevacizumab between July 5 and July 8, 2011, were reviewed. RESULTS Twelve patients were identified with endophthalmitis, presenting 1 to 6 days after receiving an intravitreal injection of bevacizumab. The injections occurred at 4 different locations in south Florida. All patients received bevacizumab prepared by the same compounding pharmacy. None of the infections originated at the Bascom Palmer Eye Institute, Miami, Florida, although 9 patients presented to its tertiary-care ophthalmic emergency room for treatment, and 3 additional patients were seen in consultation. All patients were treated initially with a vitreous tap and injection; 8 patients subsequently received a vitrectomy. Microbiology cultures for 10 patients were positive for Streptococcus mitis/oralis. Seven unused syringes of bevacizumab prepared by the compounding pharmacy at the same time as those prepared for the affected patients also were positive for S. mitis/oralis. After 4 months of follow-up, all but 1 patient had count fingers or worse visual acuity, and 3 required evisceration or enucleation. Local, state, and federal health department officials have been investigating the source of the contamination. CONCLUSIONS In this outbreak of endophthalmitis after intravitreal bevacizumab injection, Streptococcus mitis/oralis was cultured from the majority of patients and from all unused syringes. Visual outcomes were generally poor. The most likely cause of this outbreak was contamination during syringe preparation by the compounding pharmacy.

Emerging ciprofloxacin-resistant Pseudomonas aeruginosa

PURPOSE To report a clinical series of ciprofloxacin-resistant ocular isolates of Pseudomonas aeruginosa from a tertiary care ophthalmic center. METHODS Review of in vitro sensitivities of all ocular isolates of P. aeruginosa be tween July 1991 and September 1998. In vitro resistance was defined as a minimum inhibitory concentration of 4 or more microg per ml. RESULTS Nine of 423 ocular isolates of P. aeruginosa showed in vitro resistance to ciprofloxacin. From 1991 to 1994, 0.44% (1/227) of ocular isolates were resistant to ciprofloxacin, whereas from 1995 to 1998, 4.1% (8/ 196) of ocular isolates showed in vitro resistance (P = .014). CONCLUSIONS Ciprofloxacin-resistant P. aeruginosa has been identified in recent clinical ocular specimens. Ciprofloxacin resistance among ocular isolates of P. aeruginosa is a local and worldwide concern.

Polymerase Chain Reaction Analysis of Aqueous and Vitreous Specimens in the Diagnosis of Posterior Segment Infectious Uveitis

PURPOSE To assess polymerase chain reaction (PCR) analysis of intraocular fluid as a test for infectious uveitis of the posterior segment in a representative patient population. DESIGN Retrospective, interventional case series. METHODS One hundred and thirty-three patients with possible infectious chorioretinitis underwent PCR testing of aqueous or vitreous in a university setting. Baseline characteristics predictive of test positivity were identified. Positive and negative predictive values were calculated. RESULTS Four hundred and thirty-three PCR tests of 105 aqueous and 38 vitreous specimens (mean, 3.3 tests per patient) identified 77 of the 95 patients with a final clinical diagnosis of infectious uveitis (81%). Herpes simplex virus, varicella zoster virus, and cytomegalovirus PCR analysis were performed in almost all cases, with fewer tests for toxoplasmosis or Epstein-Barr virus. Clinical features associated with positive PCR results were retinal vascular inflammation (P < .001), optic nerve involvement (P = .008), immunocompromised state (P = .039), and extensive retinitis (P = .002). Cases sampled within one week of presentation were more likely to have positive PCR results than those sampled later (P = .071). The predictive value of positive and negative tests was 98.7% and 67.9%, respectively, in this patient group. Alteration in treatment based on PCR and syphilis serologic results led to resolution in 25 of 26 patients after treatment was changed. CONCLUSIONS PCR testing is a useful adjunct in the diagnosis of infectious causes of posterior uveitis. Cases with vascular or optic nerve inflammation, extensive retinitis, or immunocompromise are more likely to have positive PCR results and may benefit from PCR testing of aqueous humor.

Endogenous Fungal Endophthalmitis: Causative Organisms, Management Strategies, and Visual Acuity Outcomes

PURPOSE To report the causative organisms, management strategies, and visual outcomes in endogenous fungal endophthalmitis. DESIGN Observational case series. METHODS Microbiologic and medical records were reviewed retrospectively for all patients with culture-positive endogenous fungal endophthalmitis between January 1, 1990, and July 1, 2009. RESULTS Study criteria were met in 65 eyes of 51 patients with mean follow-up of 18 months. Yeasts were the most common causative organism in 38 (75%) patients compared with molds in 13 (25%) patients. Retinal detachment occurred in 17 eyes (26%). Visual acuity of 20/200 or better was present in 28 (56%) eyes with yeasts and in 5 (33%) eyes with molds at the last follow-up. CONCLUSIONS Yeasts were the most common cause of culture-proven unilateral or bilateral endogenous fungal endophthalmitis. Endogenous fungal endophthalmitis generally is associated with poor visual acuity outcomes, especially when caused by molds. Retinal detachment is a frequent occurrence during follow-up.

Endophthalmitis caused by Pseudomonas aeruginosa

OBJECTIVE To investigate the clinical settings and treatment outcomes for endophthalmitis caused by Pseudomonas aeruginosa. DESIGN Retrospective, noncomparative, consecutive case series. METHODS The medical records were reviewed of all patients treated for P. aeruginosa endophthalmitis at a single institution between January 1, 1987, and December 31, 2001. MAIN OUTCOME MEASURES Final visual acuity and rate of enucleation or evisceration. RESULTS The study included 28 eyes of 28 patients with a median age of 75 years (range, 5-93 years). The clinical setting of endophthalmitis included: cataract surgery (n = 9), corneal ulcer (n = 7), penetrating keratoplasty (n = 5), bleb associated (n = 2), glaucoma drainage implant (n = 2), pars plana vitrectomy (n = 1), iris cyst removal (n = 1), and trauma (n = 1). In acute-onset postoperative cases (n = 10), the median interval between surgery and presentation with endophthalmitis was 4 days (range, 1-26 days). The median duration of symptoms was 1 day, and all patients were treated on the day of diagnosis. Eleven patients (39%) had hand motions or better vision in the infected eye at the time of initial diagnosis. Because of no light perception visual acuity, necrosis of cornea and sclera, and intractable pain, 7 eyes (25%) underwent evisceration or enucleation as initial treatment; of the remaining 21 eyes, intravitreal antibiotics were administered in all cases and intravitreal dexamethasone was administered in 15 cases (71%). Pars plana vitrectomy was performed in 12 patients (43%). The organism was sensitive to the initial antibiotics administered in all but 2 cases. Final visual acuity was 5/200 or better in 2 of 28 eyes (7%). Nineteen patients (68%) had a final visual acuity outcome of no light perception, and no patient achieved a final visual acuity of better than 20/400. Overall, 18 of the 28 eyes (64%) were either eviscerated or enucleated. CONCLUSIONS Endophthalmitis caused by P. aeruginosa is associated with poor visual outcomes despite prompt treatment with intravitreal antibiotics to which the organisms were sensitive.

Exogenous Fungal Endophthalmitis: Microbiology and Clinical Outcomes

OBJECTIVE To report the fungal isolates, treatment strategies, and clinical outcomes for a large series of patients with exogenous fungal endophthalmitis. DESIGN Retrospective, single institution, consecutive case series. PARTICIPANTS All patients treated at Bascom Palmer Eye Institute between January 1, 1990, and June 30, 2006, for culture-proven exogenous fungal endophthalmitis. METHODS Microbiologic and medical records were reviewed for all patients with intraocular cultures positive for fungal organisms and clinically diagnosed exogenous endophthalmitis. MAIN OUTCOME MEASURES Fungal isolates, treatment strategies, visual acuity, and rate of enucleation. RESULTS Culture-positive exogenous fungal endophthalmitis occurred in 41 eyes, including 18 cases (44%) associated with fungal keratitis, 10 cases (24%) occurring after penetrating ocular trauma, and 13 cases (32%) after intraocular surgery. Filamentous fungi (molds) accounted for 35 cases (85%), and Candida species (yeasts) accounted for 6 cases (15%). Although most keratitis cases were caused by Fusarium (13 of 18; 72%), Aspergillus was the most common isolate in postoperative cases (5 of 13; 38%). Open-globe cases were caused by a broader spectrum of fungi. As initial treatment, 30 (73%) patients received intraocular amphotericin B, but at least 3 antifungal agents were used in 24 (59%) cases. At least 1 pars plana vitrectomy was performed in 25 (61%) eyes, and 29 (71%) eyes underwent 3 or more procedures, including surgeries and intraocular injections. Although a final vision of 20/400 or better was achieved in 22 (54%) eyes, all but 1 of these were either in the keratitis (11 of 18) or the postoperative (10 of 13) groups. Conversely, although 10 (24%) of 41 eyes were enucleated, 7 of these were among the open-globe patients. CONCLUSIONS This report highlights the differences between the clinical categories of exogenous fungal endophthalmitis. Although 85% of all cases were caused by molds, most commonly Fusarium and Aspergillus, the most common fungal genera varied by clinical category. Amphotericin B was the most commonly used antifungal agent, but most cases were treated with at least 3 different antifungal agents. Final visual outcomes were variable, with the open-globe-associated patients having the poorest outcomes. Overall, 44% of patients achieved a final visual acuity of 20/80 or better.