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Purpose: To curtail the potential of donor corneal tissue disseminating fungi to the recipient抯 eye, we evaluated the addition of amphotericin B to McCarey?Kaufman (M?K)梒orneal storage medium supplemented with colistin. Methods: Amphotericin B was examined for its ability to inhibit the growth of Candida albicans and Aspergillus flavus using a microbroth dilution test and checkerboard assay in combination with only gentamicin and a combination of colistin, gentamicin, and amphotericin B. The safety on epithelium and endothelium was evaluated by 3?(4,5?dimethylthiazol?2?yl)?2, 5?diphenyltetrazolium bromide (MTT) assay. Results: The minimal inhibitory concentration of gentamicin was found to be >256 ?g/ml against both C. albicans and A. flavus, whereas that of amphotericin B was found to be in a range of 0.25�5 and 1�?g/ml for C. albicans and A. flavus, respectively. According to the checkerboard assay, 80% (4/5) of C. albicans isolates and 100% (5/5) of A. flavus isolates responded synergistically to the combination of amphotericin B and gentamicin, but only 20% (1/5) of C. albicans isolates showed an additive effect. None of the tested isolates displayed antagonism. The combined effect of the three drugs also did not display any antagonistic effect. Additionally, the MTT assay reveals no toxic effect of the antimicrobials used on corneal epithelial and endothelial cells. Conclusion: In vitro experiments demonstrate that amphotericin B is not toxic to either epithelium or endothelium and is a promising additive to the M?K medium supplemented with colistin.
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A 42-year-old male post-renal transplantation presented with sudden diminution of vision in the left eye. The right eye was lost following a failed vitreoretinal surgery 5 years ago. The patient had been hospitalized 4 months prior for coronavirus disease 2019 infection with a good recovery. The presenting visual acuity was 20/600 in the right eye and 20/250 in the left eye. Fundus examination revealed a sub-macular sub-retinal abscess in the left eye. Sub-retinal aspiration of the abscess revealed Candida albicans. The patient was managed with repeated intravitreal amphotericin B injections, following which the abscess resolved with scarring and vision improving to 20/60.
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Purpose: To assess the efficacy of the addition of polymyxin E (colistin) in the McCarey-Kaufman (MK) corneal storage solution against multi-drug resistant strains of Enterobacteriaceae, Staphylococcus aureus, and Candida spp. Methods: A standard micro broth dilution test and a checkerboard assay were performed for five multi-drug resistant (MDR) clinical strains of P. aeruginosa and five clinical strains of methicillin-resistant S. aureus (MRSA) and C. albicans against colistin and gentamicin alone and in combination. The minimum inhibitory concentration (MIC) and the fractional inhibitory concentration index (FICI) were calculated to assess the efficacy of each combination. Results: The MIC of colistin was in the range of 1–2 ?g/mL for P. aeruginosa, whereas it was 256–1024 ?g/mL against S. aureus. In comparison, the MIC of gentamicin was found to be 0.5–512 ?g/mL and 0.5–8 ?g/mL against P. aeruginosa and S. aureus, respectively. All five isolates of C. albicans did not exhibit any susceptibility to either colistin or gentamicin even at a concentration of ? 512 ?g/ mL each. The checkerboard assay was performed to evaluate the nature of the interaction of the combination of colistin and gentamicin. Based on the FICI, it was observed that the colistin and gentamicin combination has a maximum synergistic effect (FIC <0.5) in 80% (4/5) for S. aureus isolates, whereas the maximum additive effect (FIC >0.5–4) was 100% (5/5) for P. aeruginosa and the minimum additive effect was 20% (1/5) for S. aureus isolates. Antagonism (FIC ? 4) was not observed in any combination between the strains used in the study. Both colistin and gentamicin alone or in combination were, however, ineffective against Candida spp. Conclusion: The addition of colistin has an inhibitory effect on bacterial contamination that could be possibly caused by MDR strains and could potentially be considered as an additional additive in corneal storage media.
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Purpose: To compare the clinicomicrobiological features and outcomes in patients with infectious endophthalmitis caused by biofilm?positive (BP) and biofilm?negative (BN) bacteria. Methods: This was a prospective, interventional, comparative, nonrandomized, consecutive case series. Culture?positive bacterial endophthalmitis cases from August 1, 2018 to July 31st 31, 2019 were included. All vitreous samples were tested for biofilm using crystal violet plate and XTT (2,3?bis?(2?methoxy?4?nitro?5?sulfophenyl)?2H?tetrazolium?5?carboxanilide) methods and classified as BN and BP. The antibiotic susceptibility of all organisms was determined. Anatomic and functional success was defined as intraocular pressure >5 mm Hg and final best?corrected vision ?20/400, respectively, at last visit. Results: There were 50 eyes in the BN group and 33 eyes in the BP group. BN group eyes required 2.86 ± 1.45 surgical interventions, and BP group eyes needed surgical 6.36 ± 2.89 interventions, P < 0.0001, 95% Confidence Interval, CI: 2–4. Median follow?up was 6 and 5 months, respectively (P = 0.33). Final logMAR vision was a median of 1.2 and 1.9 respectively; P = 0.0005, 95% C.I.: 0.4–1.7. Functional success was achieved in 44% and 21.2% (P = 0.03, 95% C.I.: 1.86%–40.08%) and anatomic success was achieved in 68% and 42.42%, respectively (P = 0.02, 95% C.I.: 3.85%–45.47%). The antimicrobial resistance patterns between the two groups were comparable. Conclusion: Endophthalmitis caused by the biofilm?forming bacteria needs a greater number of surgical interventions. The anatomic and functional outcomes are poorer than non?biofilm?forming bacterial endophthalmitis. The increased virulence and poorer outcomes can be hypothesized to be due to the physical barrier effect of the biofilm on the antibiotics
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Purpose: This study aimed to analyze the clinical presentations, microbiology, and management outcomes of post–cataract surgery endophthalmitis, with and without intracameral moxifloxacin prophylaxis. Methods: This study was designed as a retrospective, consecutive, comparative case series. Records of consecutive cataract surgery from January 1, 2015, till June 30, 2020, were analyzed. The cases that developed endophthalmitis were analyzed. The endophthalmitis cases were divided by their prophylaxis treatment into two groups: with intracameral moxifloxacin (ICM) and without (N?ICM). Inclusion criteria were (1) age ? 18 years, (2) cataract surgery with intraocular lens implantation, (3) endophthalmitis within 6 weeks of cataract surgery, and (4) cataract surgery in the institute by any of the three methods—phacoemulsification, manual small incision cataract surgery, and extracapsular cataract extraction. Results: In the study period, 66,967 cataract surgeries were performed; 48.7% (n = 32,649) did not receive ICM. There was no difference between the N?ICM and ICM groups in the incidence of clinical (n = 21, 0.064% and n = 15, 0.043%; P = 0.23) and culture proven (n = 19, 0.033% and n = 11, 0.023%; P = 0.99) endophthalmitis, respectively. Greater number of patients in the N?ICM group had lid edema (76.2% vs. 40%; P = 0.03), corneal edema (71.4% vs. 33.3%; P = 0.03) and lower presenting vision with available correction (logMAR [logarithm of the minimum angle of resolution] 1.26 ± 1.2 vs. logMAR 0.54 ± 0.85; P = 0.02). The final best?corrected visual acuity following treatment was worse in the N?ICM group (logMAR 1.26 ± 1.2 vs. 0.54 ± 0.85; P = 0.02). Conclusion: Endophthalmitis after intracameral moxifloxacin may have relatively milder signs and symptoms and may respond better to treatment.
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BACKGROUND: To determine the antibacterial activity of newer fluoroquinolones and compare their activity between ciprofloxacin-susceptible and resistant bacterial isolates from patients with keratitis and endophthalmitis. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) of ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin and moxifloxacin was determined for 123 bacterial isolates, using E test. Among the 123 isolates, 68 were gram-positive (Staphylococcus spp, Streptococcus spp, Corynebacterium spp, Bacillus spp.) and 55 were gram-negative (Pseudomonas aeruginosa). The bacterial isolates were divided into three groups: susceptible/intermediate/resistant to ciprofloxacin. The MIC values for various fluoroquinolones were compared between the three groups and between gram-positive and gram-negative bacteria. RESULTS: For gram-positive isolates, median MICs of fourth generation fluoroquinolones were lower than second generation. The median MIC was lowest for gatifloxacin and moxifloxacin (0.094 mg/ml) in ciprofloxacin-susceptible isolates of gram-positive bacteria. For ciprofloxacin-susceptible gram-negative bacteria, the median MIC of ciprofloxacin (0.19 mg/ml) was significantly lower than ofloxacin, levofloxacin, gatifloxacin and moxifloxacin (1.5, 0.5, 0.5 and 2 mg/ml respectively). Ciprofloxacin-resistant isolates of gram-positive bacteria showed higher MIC of levofloxacin, moxifloxacin and gatifloxacin though they remained susceptible to them. None of the fluoroquinolones were effective against ciprofloxacin-resistant gram-negative bacteria. Overall, for gram-positive bacteria, median MICs of levofloxacin, moxifloxacin and gatifloxacin were below ciprofloxacin, the MIC of gatifloxacin and moxifloxacin was equal for gram-positive bacteria. CONCLUSIONS: Levofloxacin, gatifloxacin and moxifloxacin are statistically more effective against gram-positive bacteria, the latter two being equally effective. Ciprofloxacin remains the most effective fluoroquinolone against gram-negative bacteria.