Endophthalmitis prophylaxis by intracameral antibiotics: In vitro model comparing vancomycin, cefuroxime, and moxifloxacin

Endophthalmitis after cataract surgery and effect of different intracameral antibiotic regimes in Sweden 2011-2017: national registry study

PURPOSE

To study the incidence, predictive factors, etiology, and visual consequences of postoperative endophthalmitis (PE) in relation to 3 intracameral (IC) antibiotic regimes.

SETTING

Swedish National Cataract Register entries from 2011 through 2017.

DESIGN

Observational retrospective study.

METHODS

PE incidence, influencing factors, bacteriology, and visual outcome were analyzed regarding the 3 major prophylactic IC protocols.

RESULTS

The overall incidence of PE was 0.023% or 177 cases in 764 513 cataract procedures. Analyzed per IC regime, the rates of PE were 0.024% (126 cases in 514 916 surgeries) for cefuroxime, 0.020% (25 cases in 122 340 surgeries) for moxifloxacin, and 0.017% (20 cases in 121 045 surgeries) for combined cefuroxime-ampicillin. Incidences were not statistically significantly different from one another. Gram-positive bacteria caused 89.0% of culture positive cases. Enterococci as pathogens were significantly more frequent with IC cefuroxime than with moxifloxacin, P = .006, or cefuroxime-ampicillin, P < .001, while streptococci other than enterococci were more common with moxifloxacin than with cefuroxime, P < .001. Bacterial susceptibility to the given antibiotics was demonstrated in 21.3% of PE cases treated with cefuroxime, which was statistically significantly lower than proportions found with cefuroxime-ampicillin, 60.0%, P = .015, or with moxifloxacin, 88.2%, P < .001. Visual outcome worse than 20/200 was similar in the groups ranging from 42.0% to 53.7%.

CONCLUSIONS

No statistically significant differences in PE incidence or visual outcome results between treatment groups were demonstrated. However, differences in etiology and bacterial sensitivity were found between the prophylactic IC treatments.

Relative efficacy of intracameral moxifloxacin injection methods

PURPOSE

To determine the amount of moxifloxacin remaining in the anterior chamber (AC), immediately after its injection using 3 current injection methods, assuming mixing and fluid exchange with the AC contents during injection of the drug, and to determine the most desirable injection method.

SETTING

Department of Ophthalmology and Vision Sciences and Institute of Biomedical Engineering, University of Toronto, Toronto, Canada.

DESIGN

Mathematical modeling.

METHODS

Mathematical modeling using first-order mixing methods were used to assess mixing.

RESULTS

The Kaiser method of injecting 0.5 mL × 100 μg/0.1 mL does not achieve the desired 500 μg level of moxifloxacin in the AC. The "straight from the bottle" method of injecting 0.1 mL × 500 μg/0.1 mL is fraught with potential error, yielding a relatively unreliable final amount in the AC. Injecting 0.5 to 0.6 mL × 150 μg/0.1 mL yields a result closest to the desired goal.

CONCLUSIONS

Based on the calculation, the most accurate of current methods to deliver 500 μg moxifloxacin intracamerally is the method of 150 μg/0.1 mL × 0.5 to 0.6 mL.

Surgical Antimicrobial Prophylaxis in Patients of Neonatal and Pediatric Age Subjected to Eye Surgery: A RAND/UCLA Appropriateness Method Consensus Study

Ocular surgery encompasses a wide range of procedures, including surgery of the tear ducts, eyelid, cornea and conjunctiva, lens, ocular muscle, and vitreoretinal and iris surgery. Operations are also performed for the removal of tumors, repairs of ocular trauma and, finally, corneal transplantation. Antibiotic prophylaxis for the prevention of surgical site infections (SSIs) in ocular surgery is a complex field in which shared lines of action are absent. In light of the scarcity of shared evidence in the use of ocular antimicrobial prophylaxis for the pediatric population, this consensus document aims to provide clinicians with a series of recommendations on antimicrobial prophylaxis for patients of neonatal and pediatric age undergoing eye surgery. The following scenarios are considered: (1) intraocular surgery; (2) extraocular surgery; (3) ocular trauma; (4) ocular neoplasm; (5) ocular surface transplantations; (6) corneal grafts. This work has been made possible by the multidisciplinary contribution of experts belonging to the most important Italian scientific societies and represents, in our opinion, the most complete and up-to-date collection of recommendations regarding clinical actions in the peri-operative environment in eye surgery. The application of uniform and shared protocols aims to improve surgical practice, through the standardization of procedures, with a consequent reduction of SSIs, also limiting the phenomenon of antimicrobial resistance.

Immediately sequential bilateral cataract surgery: an academic teaching center's experience

PURPOSE

To evaluate the safety and outcomes of immediately sequential bilateral cataract surgery (ISBCS) at a Canadian academic teaching center.

SETTING

Tertiary university teaching hospital of Laval University, Quebec City, Canada.

DESIGN

Retrospective cohort study.

METHODS

2003 consecutive patients (4006 eyes) who underwent ISBCS under topical anesthesia from January 2019 to December 2019 were included. All charts were retrospectively reviewed. Outcome measures included intraoperative and postoperative complications, postoperative uncorrected distance (UCVA) and pinhole (PHVA) visual acuities, and autorefraction measurements.

RESULTS

4006 eyes from 1218 (60.8%) female and 785 (39.2%) male patients with a mean age of 74 ± 8 years had a mean preoperative visual acuity of 0.503 logMAR (Snellen 20/63). The mean axial length was 23.53 ± 1.37 mm. Most eyes had monofocal intraocular lenses (IOLs) implanted (n = 3738, 93.3%) followed by toric (n = 226, 5.6%), multifocal (n = 25, 0.6%), and multifocal toric (n = 17, 0.4%) IOLs. Intraoperative complications included 14 (0.3%) posterior capsule ruptures with 5 (0.1%) requiring sulcus IOL placement, and 7 (0.2%) partial zonulysis, with 3 requiring capsular tension rings (0.07%). There were no cases of endophthalmitis or toxic anterior segment syndrome. Mean 5-week postoperative UCVA was 0.223 (Snellen 20/33), PHVA was 0.153 (Snellen 20/28) with a mean spherical equivalent of -0.21 diopters.

CONCLUSIONS

ISBCS performed following International Society of Bilateral Cataract Surgeons recommended guidelines is a safe procedure. This cohort of 4006 eyes had very few complications, with none attributable to the surgery being done bilaterally. The UCVA, PHVA, and refractive outcomes were good.

Endophthalmitis Prophylaxis Failures in Patients Injected With Intracameral Antibiotic During Cataract Surgery

PURPOSE

To estimate the association of cefuroxime and moxifloxacin in relation to the occurrence of endophthalmitis following phacoemulsification cataract surgery.

DESIGN

Retrospective clinical cohort study.

METHODS

We studied patients with noncomplex phacoemulsification cataract surgery in Kaiser Permanente Northern California during 2014-2019. Data were obtained for acute, postoperative endophthalmitis within 90 days of phacoemulsification, including culture and antibiogram results, intracameral and topical antibiotic agent, and dose. In a post hoc analysis, we also examined preoperative anterior chamber depth (ACD) and postoperative anterior chamber volume (ACV).

RESULTS

Of 216,141 surgeries, endophthalmitis occurred in 0.020% of moxifloxacin-injected eyes and 0.013% of cefuroxime eyes (relative risk 1.62 with 95% CI 0.82-3.20, P = .16). Of the 34 (0.016%) cases of endophthalmitis, cefuroxime 1 mg was injected into 13 eyes and moxifloxacin 0.1% into 21 eyes. Organisms with antibiograms were identified in 12 (35%) cases. Of these, bacteria recovered from cefuroxime-injected eyes were resistant to cefuroxime in all cases (4/4), with Enterococcus comprising half of these. In eyes injected with moxifloxacin 0.1%, 6 out of 7 organisms were sensitive to moxifloxacin injected with 0.1 mL and in 1 eye injected with 1 mL. Streptococcus was the most common organism recovered (6/9) in moxifloxacin-injected eyes. Preoperative ACD and postoperative calculated ACV were higher in eyes injected with moxifloxacin.

CONCLUSIONS

Endophthalmitis cases with positive cultures were generally related to organism resistance in cefuroxime eyes but to sensitive organisms in moxifloxacin eyes. Moxifloxacin doses may have been insufficient in eyes with larger ACV.

Postoperative endophthalmitis with and without intracameral moxifloxacin prophylaxis in a high volume surgery setting

Objective

This study was conducted to understand the effects of intracameral moxifloxacin in decreasing the incidence of postoperative endophthalmitis after cataract surgery in an eye hospital with a high volume surgical load.

Methods and analysis

In this single-centre, retrospective, clinical registry-based study, we compared the rates of postoperative endophthalmitis in 31 340 cataract surgery patients operated during 22 months after June 2018 who received intracameral moxifloxacin to 80 643 patients operated during 41 months before June 2018 who did not receive intracameral moxifloxacin. All patients received subconjunctival gentamycin and dexamethasone. Combined surgical procedures were excluded from the study.

Results

There was a significant reduction (p<0.001) of postoperative endophthalmitis rates in cataract surgeries from 0.144% (116/80 643) to 0.025% (8/31 340) after initiation of intracameral moxifloxacin. Endophthalmitis rates decreased from 0.120% (12/9942) to 0.009% (1/10 787) in phacoemulsification group and from 0.147% (104/70 701) to 0.034% (7/20 553) in manual small-incision cataract surgeries. Gram-positive organisms including Coagulase-negative staphylococci (37.9%, n=11) and Staphylococcus aureus (S. aureus 34.5%, n=10) were the most common organisms isolated out of 29 culture-positive cases. 24.1% (28/116) endophthalmitis cases in group without moxifloxacin were culture positive compared with 14.3% (1/7) of cases in moxifloxacin group. 72% (n=8) of the Coagulase-negative staphylococci and 80% of S. aureus isolates (n=8) showed in vitro sensitivity to moxifloxacin.

Conclusion

Prophylactic use of intracameral moxifloxacin injection in addition to subconjunctival gentamycin in cataract surgery is associated with a significant decrease in rates of postoperative endophthalmitis when compared with the use of subconjunctival gentamycin alone in high volume settings.

Toxic Anterior Segment Syndrome with Intracameral Moxifloxacin: Case Report and Review of the Literature

A case of severe anterior segment toxicity secondary to high-volume, undiluted intracameral moxifloxacin for endophthalmitis prophylaxis is reported. We examine the other reported cases of toxicity after intracameral moxifloxacin, as well as iris depigmentation and transillumination syndromes after oral and topical fluoroquinolone exposure. Additionally, we review the literature on safety, efficacy, and appropriate dosing of intracameral antibiotics with a focus on moxifloxacin.

Incremental effect of topical and oral moxifloxacin administration with surgical intracameral prophylaxis

OBJECTIVE

To determine how supplemental perioperative topical or oral moxifloxacin administration impacts anterior chamber (AC) antibiotic concentrations beyond those achieved by intracameral (IC) administration alone for postoperative endophthalmitis (POE) prophylaxis.

DESIGN

Mathematical modeling.

METHODS

The mathematical model developed by Arshinoff, Modabber, and Felfeli was adapted to calculate all reported data. A literature review of pharmacokinetic data for topical and oral moxifloxacin was used to inform the expansion of the model.

RESULTS

Our previously constructed IC model yields a dose of moxifloxacin in the AC sufficient to confer bactericidal coverage against the most common POE pathogen, methicillin-sensitive Staphylococcus aureus (MSSA), for ∼40 hours postoperatively. Topical 0.5% moxifloxacin eye drops alone, administered every 4 or 6 hours, achieve an AC concentration just above or at the mutant prevention concentration (MPC) for MSSA, respectively, whereas 8-hour dosing produces levels generally below the MPC. Combining topical moxifloxacin with IC increases the AC concentration above IC alone only after 20 or more hours and maintains the AC concentration at, or just below, the MPC for MSSA for as long as the drops are continued. Combined perioperative oral moxifloxacin with IC increases AC levels over IC alone only after 16 hours and maintains the AC concentration above the MPC for MSSA for an additional 5 hours, owing to the systemic reservoir.

CONCLUSIONS

The addition of topical or oral moxifloxacin supplemental to IC can extend the duration of bactericidal coverage for the most common, but not the most resistant POE-causing pathogens.

Simultaneous quantification of cefuroxime and clindamycin in human lumbar anulus fibrosus, nucleus pulposus and serum via UPLC-MS/MS

BACKGROUND

This study aimed to develop a sensitive, accurate method for simultaneously quantifying cefuroxime and clindamycin in human serum, lumbar anulus fibrosus and nucleus pulposus.

METHODS

Cefuroxime and clindamycin were quantified using ultra high-performance liquid chromatography-electrospray ionization tandem mass spectrometry in multiple-reaction-monitoring mode on a triple-quadrupole AB Qtrap 5500 system in positive ion mode. Internal standards were D₃-cefuroxime and D_3,¹³C-clindamycin. Samples were pretreated by precipitating total protein.

RESULTS

The method showed high sensitivity and good linearity over broad calibration ranges from 100 to 100 000 ng/mL for cefuroxime and 10 to 10 000 ng/mL for clindamycin in serum, and from 10 to 10 000 ng/mL for cefuroxime and 1 to 1 000 ng/mL for clindamycin in lumbar nucleus pulposus. In all sample types, correlation coefficients were greater than 0.99, intra- and inter-day precision (relative standard deviation) was less than 15%, and accuracy (relative error) was within 14% for both analytes. This method was effective at quantifying penetration of cefuroxime and clindamycin in patients undergoing oblique lumbar interbody fusion surgery.

CONCLUSIONS

A very sensitive, specific method for simultaneous detection of cefuroxime and clindamycin has been developed for human lumbar anulus fibrosus, nucleus pulposus and serum samples.

Comparison of the local effects of different intracameral cefuroxime solutions on rabbit cornea

PURPOSE

We aimed to compare the local effects of intracameral cefuroxime diluted in normal saline (SF groups) against those of cefuroxime in balanced salt solution (BSS group) on the cornea of rabbits.

MATERIALS AND METHODS

Fourteen New Zealand albino rabbits were randomised into two groups. The right eyes of the rabbits in the SF group I were injected intracamerally with 1 mg cefuroxime diluted with 0.1 mL normal saline (n = 7), whereas the right eyes of the BSS group II were injected with 1 mg intracameral cefuroxime diluted with 0.1 mL with balance salt solution, and the left eyes of all rabbits received no treatment group III (control group). Corneal thickness was measured with pachymetry before and 1 week after the injection. Corneal samples were evaluated with light, specular and electron microscopy.

RESULTS

Mean endothelial cell count was lower in the SF than in the BSS and control groups. Although an increase in corneal thickness was found in both treatment groups, this was not the case for the control group. The corneal endothelium preserved its hexagonal structure in all groups. Although both treatment groups showed a loss of endothelial microvilli, this was more prevalent in the SF group. However, microvilli were preserved in the control group. Dissolution of tight junctions in corneal endothelium was observed in the SF group only. Mitochondrial swelling, coarsening of endoplasmic reticulum, cytoplasmic vacuolisation, and increased endothelial cell sizes were the same in both treatment groups but was not observed in the control group. Thicker and more oedematous corneal stroma were observed in the SF group compared with the BSS and control groups.

CONCLUSION

Dilution of intracameral cefuroxime in BSS yielded superior results compared with dilution in normal saline owing to toxicity to the endothelial cells and decline in the endothelial cell number, resulting in intracellular and intercellular morphological changes. BSS or any other solution with proven safety should be used in clinical studies.

Commonly used intracameral antibiotics for endophthalmitis prophylaxis: A literature review

Endophthalmitis is a serious complication of cataract surgery that occurs in thousands of patients each year. To decrease the incidence of postoperative endophthalmitis, many surgeons inject intracameral antibiotics (cefuroxime, moxifloxacin, and vancomycin) routinely at the end of surgery. A large number of recently published retrospective studies and large database analyses have reported decreased endophthalmitis rates with routine antibiotic use, and the only prospective, multicenter, randomized trial performed by the European Society of Cataract and Refractive Surgery demonstrated that intracameral cefuroxime decreases the incidence of postoperative endophthalmitis. Routine cefuroxime use has become common in many European countries, whereas moxifloxacin is the most commonly used drug in India, and vancomycin use predominates in Australia. The decision regarding whether or not to use intracameral prophylaxis and the drug that is selected varies considerably throughout the world because of antibiotic availability and cost, and the spectrum of causative organisms. Adverse events due to intracameral antibiotics are infrequent, but complications such as hemorrhagic occlusive retinal vasculitis have been reported. Because additional prospective, comparative trials have not been performed, a consensus regarding best practices to prevent postoperative endophthalmitis has not been reached. Additionally, many surgeons do not routinely use intracameral antibiotics because they believe them unnecessary with modern aseptic techniques, small incision surgery, and shorter operating times. We discuss the most commonly used intracameral antibiotics, present the risks and potential benefits of this approach, and highlight challenges with drug compounding and safety.

Drop-free approaches for cataract surgery

PURPOSE OF REVIEW

Routine prophylaxis for adverse events following cataract surgery is evolving. Prior reliance on topical eyedrop instillation by patients is giving way to surgeon directed injections at the time of cataract surgery. The benefit of this new approach is assured delivery of drugs in standardized doses which should optimize the healing process and reduce the incidence of untoward events with higher confidence.

RECENT FINDINGS

Adoption rates of intracameral antibiotic injection amongst European and American cataract surgeons is increasing. Techniques to inject periocular corticosteroid for routine inflammation prophylaxis are also in development. In combination with intraoperative pharmacologic dilation, a drop-free modality can be achieved.

SUMMARY

Intraoperative injections offer the patient and surgeon assured drug delivery and hold promise to avoid the pitfalls of patient adherence, incorrect topical instillation, and topical drop-associated corneal issues.

Injection volume and intracameral moxifloxacin dose

PURPOSE

To test the effect of injection volume and concentration on dosing and residence time of moxifloxacin in the anterior chamber (AC).

SETTING

Kaiser Permanente, Walnut Creek, California, USA.

DESIGN

Experimental study.

METHODS

Moxifloxacin 0.5%/0.05 mL, moxifloxacin 0.5%/0.10 mL, and moxifloxacin 0.15%/0.50 mL were drawn into 5 1.0 mL syringes each, injected into tared vials, and weighed. The doses delivered were calculated. The AC concentrations and elimination rates of the drug for two AC volumes were modeled for each dosing method.

RESULTS

The 0.05 mL injection volume resulted in the greatest range (35 μg) of delivered dose compared with larger injection volumes (≤25 μg). The mathematical model predicted that variation in dosing in each group would result in differences of 12 minutes or less for the presence of the drug in the AC. Injection of 0.5%/0.1 mL produced AC concentrations above 500 μg/mL for 1.9 to 3.0 hours and above 64 μg/mL for 5.5 to 6.5 hours, depending on the AC volume; however, flushing with a 0.15% concentration sustained AC levels for 1.9 hours and 5.5 hours, respectively, for the two AC volumes.

CONCLUSIONS

Smaller injection volumes of a higher concentration moxifloxacin resulted in less accuracy and less precision in the delivered dose (0.05 mL, P = .005; 0.10 mL, P = .03); however, the clinical significance of this might vary. Injection of 0.5%/0.1 mL and flushing with 0.15%/0.5 mL of moxifloxacin would provide similar drug AC residence times according to the model. Flushing provided more consistent AC concentrations with differing AC volumes.

Toxicities of and inflammatory responses to moxifloxacin, cefuroxime, and vancomycin on retinal vascular cells

Prophylactic intracameral injection of antibiotics is commonly used to prevent endophthalmitis after cataract surgery. However, devastating visual complications have been reported including hemorrhagic occlusive retinal vasculitis (HORV).To determine the toxic and inflammatory effects of moxifloxacin, cefuroxime, and vancomycin on human retinal vascular cells, human retinal vascular endothelial cells (RVEC) and pericytes were exposed to three antibiotics, and the adverse effects were assessed by membrane damage, loss of intrinsic esterase activity, kinetic cell viability, and inflammatory cytokine secretion. Their retinal toxicity was examined by live/dead assays after an intravitreal injection of the three antibiotics into mice eyes. In vascular cells in culture, membrane damage and loss of esterase activity were induced after exposure to the three antibiotics. The toxic effects were most obvious after moxifloxacin (RVEC, ≥125 μg/mL; pericytes, ≥1000 μg/mL) at 24 h. Cefuroxime also reduced esterase activity and the membrane integrity of vascular cells but were less toxic than moxifloxacin. Kinetic cell viability testing showed that 500 μg/mL of moxifloxacin exposure induced significant decrease (29%) in the viability as early as 1 h. When the inflammatory effects of the antibiotics were examined, a significant induction of IL-8 was observed especially by RVECs after exposure to cefuroxime or vancomycin which was exacerbated by L-alanyl-γ-D-glutamyl-meso-diaminopimelic acid (Tri-DAP), a NOD1 ligand. Intravitreal injections in mice showed that cefuroxime and vancomycin caused retinal and vascular toxicity extending to the inner nuclear layers. Collectively, moxifloxacin causes immediate damage to retinal vascular cells in vitro, while cefuroxime and vancomycin induced significant inflammatory effects on vascular endothelial cells and caused retinal toxicity. Surgeons need to be cautious of the toxicity when antibiotics are used prophylactically especially by intravitreal administration.

Endophthalmitis following cataract surgery and intracameral antibiotic: Moxifloxacin resistant Staphylococcus epidermidis

Purpose

To describe an immunosuppressed patient who developed acute-onset postoperative endophthalmitis caused by a moxifloxacin-resistant strain of Staphylococcus epidermidis after cataract surgery despite the use of intracameral moxifloxacin.

Observations

A 76-year old woman with a history of birdshot chorioretinopathy controlled on systemic immunosuppression underwent uneventful cataract surgery in her right eye. Compounded intracameral moxifloxacin 0.2 cc of 1mg/0.1mL (Edge Pharmacy, Syracuse, NY) was injected intraoperatively as prophylaxis, and the patient was placed on a standard regimen of trimethoprim-polymyxin b (10000-0.1unit/mL) and prednisolone acetate 1% postoperatively. Four days later, the patient experienced a sudden decrease in vision in the right eye. Anterior chamber inflammation, vitritis, and vasculitis were seen in the operated eye. The patient underwent a vitreous tap and intravitreal injections of vancomycin (1mg/0.1mL), ceftazidime (2.25mg/0.1mL), and dexamethasone (0.4mg/0.1mL). Cultures grew Staphylococcus epidermidis, resistant to moxifloxacin (MIC ≥8mg/L). The inflammation resolved over two months. Eight months later, the patient underwent uncomplicated cataract surgery in the left eye. Intracameral antibiotics were not used, however her systemic immunosuppressive therapy was held for several weeks perioperatively. One year after the initial surgeries, the patient had an uncorrected visual acuity of 20/20 in each eye.

Conclusions and Importance

S. epidermidis, the most common cause of postoperative endophthalmitis, is increasingly resistant to fluoroquinolones. Adequate concentrations of intracameral antibiotics need to be achieved in order to exceed minimal inhibitory concentration values of the targeted pathogen. Although intracameral moxifloxacin has been reported to decrease the rate of endophthalmitis after cataract surgery, it does not eliminate the risk.