How to prevent endophthalmitis in cataract surgeries?

Microbial distributions in the conjunctiva and lacrimal sacs of patients with chronic dacryocystitis in a tertiary hospital

BACKGROUND

The aim was to clarify the distributions of bacteria in the conjunctival sac and lacrimal sac in patients with chronic dacryocystitis.

METHODS

In total, 297 (322 eyes) chronic dacryocystitis patients who underwent nasal endoscopic dacryocystorhinostomy (EN-DCR) were included. Conjunctival sac secretions from the affected eye were collected preoperatively, and lacrimal sac retention fluid from the affected side in the same patient was collected intraoperatively. Bacterial culture and drug sensitivity testing were performed to determine bacterial distributions.

RESULTS

In total, 127 bacterial isolates (49 species) were detected in 123 eyes in the conjunctival group, with a positivity rate of 38.2% (123/322); 85 bacterial isolates (30 species) were detected in 85 eyes in the lacrimal sac group, with a positivity rate of 26.4% (85/322). The positivity rates were significantly different (P = 0.001) between two groups. The gram-negative bacilli proportion in the lacrimal sac group (36/85, 42.4%) was significantly higher than that in the conjunctival sac group (37/127, 29.2%) ( P = 0.047). Positive conjunctival sac secretion culture (123/322) was significantly associated with increased ocular secretion (281/322, 87.3%) (P = 0.002). Among the culture-positive bacteria in the conjunctival sac group and the lacrimal sac group, 30/127, 23.6% and 43/127, 26.7% and 21/85, 24.7% and 20/85, 23.5% were resistant to levofloxacin and tobramycin, respectively.

CONCLUSIONS

This study illustrated differences in bacterial distributions between conjunctival sac secretions and retained lacrimal sac fluid in chronic dacryocystitis patients, with a higher proportion of gram-negative bacilli in lacrimal sac secretions. The ocular surface flora in chronic dacryocystitis patients is partially resistant to levofloxacin and tobramycin, which need to be considered by ophthalmologists.

Ciprofloxacin Loaded Nanostructured Lipid Carriers Incorporated into In-Situ Gels to Improve Management of Bacterial Endophthalmitis

Bacterial endophthalmitis (BE) is a potentially sight-threatening inflammatory reaction of the intraocular fluids or tissues caused by bacteria. Ciprofloxacin (CIP) eye drops are prescribed as first-line therapy in BE. However, frequent administration is necessary due to precorneal loss and poor ocular bioavailability. The objective of the current research was to prepare CIP containing nanostructured lipid carriers (CIP-NLCs) loaded an in situ gel system (CIP-NLC-IG) for topical ocular administration for enhanced and sustained antibacterial activity in BE treatment. CIP-NLCs were prepared by the hot homogenization method and optimized based on physicochemical characteristics and physical stability. The optimized CIP-NLC formulation was converted into CIP-NLC-IG with the addition of gellan gum as a gelling agent. Furthermore, optimized CIP-NLC and CIP-NLC-IG were evaluated for in vitro release and ex vivo transcorneal permeation studies, using commercial CIP ophthalmic solution (CIP-C) as the control. The optimized CIP-NLC formulation showed particle size, polydispersity index, zeta potential, assay and entrapment efficiency of 193.1 ± 5.1 nm, 0.43 ± 0.01, -32.5 ± 1.5 mV, 99.5 ± 5.5 and 96.3 ± 2.5%, respectively. CIP-NLC-IG with 0.2% w/v gellan gum showed optimal viscoelastic characteristics. The in vitro release studies demonstrated sustained release of CIP from CIP-NLC and CIP-NLC-IG formulations over a 24 h period. Transcorneal flux and permeability increased 4 and 3.5-fold, and 2.2 and 1.9-fold from CIP-NLC and CIP-NLC-IG formulations, respectively, when compared to CIP-C. The results demonstrate that CIP-NLC-IG could be considered as an alternate delivery system to prolong the residence time on the ocular surface after topical administration. Thus, the current CIP ophthalmic formulations may exhibit improved ocular bioavailability and prolonged antibacterial activity, which may improve therapeutic outcomes in the treatment of BE.

Conjunctival Microbial Flora in Ocular Stevens-Johnson Syndrome Sequelae Patients at a Tertiary Eye Care Center

PURPOSE

To evaluate the conjunctival microbial flora in cases of ocular Stevens-Johnson Syndrome (SJS) in a tertiary eye care center.

METHODS

This prospective study comprised 176 eyes of 88 patients with ocular SJS compared with 124 eyes of normal subjects. The conjunctival swabs were collected and sent for microbiological analysis for bacterial isolation and antibiotic sensitivity examination. The type of bacteria isolated and its antibiotic sensitivity pattern were studied.

RESULTS

Of 176 eyes, 104 (59%) had positive cultures for bacteria in cases of SJS and 16 (12.9%) had positive culture in the control group, the difference being statistically significant (P = 0.001). In the SJS group, 14 different types of bacterial isolates were identified. The most common isolate was coagulase-negative staphylococci (CNS) (30/104, 28.8%) followed by Corynebacteria species (35/104, 33.6%) and Staphylococcus aureus (19/104, 18.2%). More than 1 bacteria were isolated in 7 eyes (6.7%). Most of the isolates showed resistance to ciprofloxacin with no resistance to gatifloxacin and moxifloxacin. In the control group, only 2 bacteria were isolated, which included CNS (14/16, 87.5%) and Streptococcus pneumoniae (2/16, 12.5%). CNS showed resistance to ciprofloxacin, and S. pneumoniae was resistant to tobramycin and gentamycin.

CONCLUSIONS

Ocular SJS is associated with alteration of the normal microbial flora residing in the conjunctival sac. The study of which is vital in cases of infection in these eyes with compromised ocular surface. Mixed flora are seen more often in cases of ocular SJS as compared with controls.

Conjunctival bacterial flora in fellow eyes of patients with unilateral nasolacrimal duct obstruction and its changes after successful dacryocystorhinostomy surgery

PURPOSE

To evaluate the results of conjunctival culture in fellow eyes of patients with unilateral nasolacrimal duct obstruction (NLDO) and its changes after successful dacryocystorhinostomy (DCR) surgery.

METHODS

In this prospective study, 71 adult patients with unilateral NLDO and 41 age and sex-matched controls without NLDO were evaluated. The patients were divided into 2 groups based on clinical examination; group A with purulent regurgitation and group B without purulent regurgitation. They all underwent DCR. Before DCR surgery, microbiologic specimens were taken bilaterally from the conjunctiva of both eyes. Postoperative conjunctival sampling was continued weekly until the culture became negative or the colony count reached to the range of the control group.

RESULTS

There were 38 and 33 patients in groups A and B, respectively. Silicone tube was inserted for 17 patients (23.9%). The culture was positive for bacterial growth in 56 fellow eyes (79%). The conjunctival culture in the control group was positive in 17 eyes (41.4%). The mean count of colonies in a sample unit was 624.73 ± 2412.31, 195.75 ± 407.56, and 9.5 ± 1.5 for group A, group B, and controls, respectively. The mean time of normalization of specimens was 1.43 ± 0.69 weeks (range 1-4). Higher colony count at baseline and presence of silicone tube in infected eye were significantly associated with longer normalization time for fellow eye (P < 0.001 and P = 0.003 respectively).

CONCLUSIONS

This study suggests that after successful DCR surgery, a waiting period of 4 weeks is needed for conjunctival bacterial cultures to become negative or reach the level of the normal eyes, in the fellow eyes of patients with unilateral NLDO.

Antibiotic resistance in acute postoperative endophthalmitis

Acute postoperative endophthalmitis (APE) is a serious, although infrequent, complication of eye surgery that can result in significant morbidity and costs. This review addresses APE risk factors, associated bacterial pathogens, antibiotic resistance, and prevention.

Impact of changes in antibiotic prophylaxis on postoperative endophthalmitis in a Spanish hospital

OBJECTIVE

This study aims to assess whether changes in antibiotic prophylaxis used in cataract surgery in the La Mancha Centro General Hospital, Spain, were associated with a reduced incidence of postoperative endophthalmitis (POE).

METHODS

The hospital employed two different antibiotic prophylaxis regimens during two clearly differentiated periods. In the first period (January 2000 to April 2003), subconjunctival injections of gentamicin were used while in the second (May 2003 to December 2008), vancomycin and gentamicin were added to the irrigating solution. During both periods, povidone iodine was used at the site of surgery and aminoglycoside eye drops were administered postoperatively. A Poisson regression model was used to evaluate the relationship between the incidence rate of endophthalmitis and variables such as time trends, seasonality, and change in antibiotic prophylaxis regimen.

RESULTS

During the period between 2000 and 2008, 26 cases of POE were detected after 14,285 operations for an incidence rate (IR) of 1.8 cases per 1000 procedures (95% confidence interval 1.2-2.7 cases out of 1000 procedures). In the period prior to the change in prophylaxis, 23 cases were detected (IR 4.5 cases/1000 procedures) while only three cases were observed in the period after the change (IR 0.3 cases/1000 procedures). A total of 84% of the microorganisms isolated were gram-positive, and all were sensitive to vancomycin.

CONCLUSIONS

The change in antibiotic prophylaxis regimen for cataract surgery was associated with a relevant and significant decrease in the incidence of POE.

Rate of Post-traumatic Endophthalmitis with or without Injection of Balanced Salt Solution

PURPOSE

In a study complementing a previous multicenter randomized clinical trial on prophylactic injection of intraocular antibiotics during primary repair of penetrating eye injuries (PEIs), we sought to determine whether needle entrance and injection of balanced salt solution (BSS), per se, could increase the rate of acute post-traumatic bacterial endophthalmitis (APBE).

METHODS

Patients randomized to the BSS injection arm (n=167) of the Traumatic Endophthalmitis Trial, and eligible patients who had refused enrollment and received no intraocular injections during primary repair (n=111) were compared for the development of APBE.

RESULTS

APBE occurred in 8 of 167 (4.8%) eyes in the BSS group and in 5 of 111 (4.5%) eyes in the non-injection group (P=0.91). Retained intraocular foreign bodies were present in 46 eyes including 25 (15%) eyes in the BSS injection group and 21 (18.9%) eyes in the non-injection group (P=0.38). Logistic regression analysis showed no significant difference between BSS injected and non-injected eyes in terms of APBE (P=0.69). However, the presence of intraocular foreign bodies was strongly associated with the risk of endophthalmitis (P<0.001, OR=14.1, 95% CI: 4.1-48.5).

CONCLUSION

Needle entrance and intraocular injection of BSS during primary repair of PEIs does not increase the risk of APBE.

The journey to femtosecond laser-assisted cataract surgery: new beginnings or a false dawn?

Femtosecond laser-assisted cataract surgery (FLACS) represents a potential paradigm shift in cataract surgery, but it is not without controversy. Advocates of the technology herald FLACS as a revolution that promises superior outcomes and an improved safety profile for patients. Conversely, detractors point to the large financial costs involved and claim that similar results are achievable with conventional small-incision phacoemulsification. This review provides a balanced and comprehensive account of the development of FLACS since its inception. It explains the physiology and mechanics underlying the technology, and critically reviews the outcomes and implications of initial studies. The benefits and limitations of using femtosecond laser accuracy to create corneal incisions, anterior capsulotomy, and lens fragmentation are explored, with reference to the main platforms, which currently offer FLACS. Economic considerations are discussed, in addition to the practicalities associated with the implementation of FLACS in a healthcare setting. The influence on surgical training and skills is considered and possible future applications of the technology introduced. While in its infancy, FLACS sets out the exciting possibility of a new level of precision in cataract surgery. However, further work in the form of large scale, phase 3 randomised controlled trials are required to demonstrate whether its theoretical benefits are significant in practice and worthy of the necessary huge financial investment and system overhaul. Whether it gains widespread acceptance is likely to be influenced by a complex interplay of scientific and socio-economic factors in years to come.

Outcome of endophthalmitis treatment in a tertiary referral center in southern iran

Purpose:

The purpose of this study was to investigate the causative organisms, the clinical characteristics, visual outcomes, and the incidence of acute endophthalmitis after cataract surgery.

Materials and Methods:

In this retrospective study, a chart review was performed for patients treated in a tertiary referral center for acute endophthalmitis after cataract surgery from January 2005 to December 2009. During the study period, 62 additional patients with acute postoperative endophthalmitis were referred to and treated in this center. Therefore the cohort comprised 70 patients (8 of whom underwent cataract surgery at our center, and 62 who were referred). Demographic, clinical, and laboratory data were analyzed. The primary outcome measure was final visual acuity. P<0.05 indicated statistical significance

Results:

During the study period, 7737 cataract surgeries were performed in this center. Eight (0.10%) of 7737 eyes developed acute postoperative endophthalmitis. Subgroup analysis indicated that extracapsular cataract extraction was associated with a fourfold higher risk of endophthalmitis compared with phacoemulsification. We found better initial visual acuity (VA) (≥ hand motion) (P<0.001) and negative cultures (P=0.021) were independently associated with a more favorable visual outcome. Patients with relative afferent papillary defect (RAPD) were associated with lower initial VA (P<0.001) and worse visual outcome (P=0.001). Positive microbial cultures were found for 33 (42.9%) cases. Staphylococcus aureus was the most common organism isolated. Positive cultures were more frequently found in patients with RAPD. The “gram-positive coagulase-negative” and “no growth” groups had the best visual outcome. Associated keratitis and avoiding intraocular steroids were associated with the risk of evisceration.

Conclusion:

The visual outcome after endophthalmitis was generally poor and only one eighth of the eyes achieved a final corrected visual acuity of ≥20/200. Therefore, better treatment strategies are warranted. Immediate treatment is essential and the role of primary vitrectomy requires further investigation. In addition, RAPD, as an objective test, may complement VA for predicting the prognosis and planning the course of treatment.

The role of topical antibiotics used as prophylaxis in surgical site infection prevention

Compared with systemic antibiotic therapy, the topical or local delivery of an antibiotic has many potential advantages. However, local antibiotics at the surgical site have received very limited approval in any of the surgical prophylaxis consensus guidelines that we are aware of. A review of the literature was carried out through searches of peer-reviewed publications in PubMed in the English language over a 30 year period between January 1980 and May 2010. Both retrospective and prospective studies were included, as well as meta-analyses. With regard to defining 'topical' or 'local' antibiotic application, the application of an antibiotic solution to the surgical site intraoperatively or immediately post-operatively was included. A number of surgical procedures have been shown to significantly benefit from perioperative topical prophylaxis, e.g. joint arthroplasty, cataract surgery and, possibly, breast augmentation. In obese patients undergoing abdominal surgery, topical surgical prophylaxis is also proven to be beneficial. The selective use of topical antibiotics as surgical prophylaxis is justified for specific procedures, such as joint arthroplasty, cataract surgery and, possibly, breast augmentation. In selective cases, such as obese patients undergoing abdominal surgery, topical surgical prophylaxis is also proven to be beneficial. Apart from these specific indications, the evidence for use of topical antibiotics in surgery is lacking in conclusive randomized controlled trials.

Case of endophthalmitis following intravitreal injections of bevacizumab

Purpose:

We report a case of infectious endophthalmitis that developed after the third intravitreal injection of bevacizumab. The endophthalmitis was caused by Staphylococcus epidermidis.

Methods:

Observational case series.

Results:

This was a case of a 77-year-old man who had received three intravitreal injections of bevacizumab and developed infectious endophthalmitis. Polymerase chain reaction of an aqueous humor sample showed that the endophthalmitis was caused by S. epidermidis. The patient received intravitreal ceftazidime and vancomycin, and subconjunctival injection of vancomycin. After the intravitreal injections he was treated with topical levofloxacin and cefmenoxime hydrochloride, and intravenous cefpirome. Subsequently, the ocular inflammation gradually decreased and his visual acuity remained at 30/200.

Conclusions:

Our findings indicate that endophthalmitis can develop after intravitreal bevacizumab injections. Polymerase chain reaction is useful for differentiation from sterile endophthalmitis.

Refractive surgical correction of presbyopia with the AcuFocus small aperture corneal inlay: two-year follow-up

PURPOSE

To evaluate the safety and efficacy of the AcuFocus Corneal Inlay 7000 (ACI 7000) implanted in emmetropic presbyopic patients for the improvement of near and intermediate vision over 2-year follow-up.

METHODS

This prospective, non-randomized, non-comparative study included 32 naturally emmetropic presbyopic patients. The intracorneal inlay was implanted in the non-dominant eye over the pupil by creating a superior-hinged flap with the IntraLase 60-kHz femtosecond laser (Abbott Medical Optics). Inlay centration was over the line of sight. Minimum postoperative follow-up was 24 months.

RESULTS

After mean follow-up of 24.2±0.8 months (range: 24 to 26 months), 96.9% of patients read J3 or better in the implanted eye. Mean binocular uncorrected near visual acuity improved from J6 preoperatively to J1 after 24 months. Mean binocular uncorrected intermediate visual acuity (UIVA) was 20/20 at 1 month and remained 20/20 throughout 24-month follow-up, with 71.9% of eyes reaching UIVA of 20/20 or better. At 24 months, mean uncorrected distance visual acuity was 20/20 in the implanted eye and 20/16 binocularly. No inlay was explanted during the study. Two decentered inlays were recentered after 6 months because of in-sufficient increase in near and intermediate visual acuity. Both patients' near and intermediate visual acuity improved significantly after recentration.

CONCLUSIONS

The ACI 7000 seems to provide a safe and effective treatment for presbyopia over follow-up of 2 years.

Effect of delivery of MMP inhibitors from PDMS as a model IOL material on PCO markers

Posterior capsule opacification (PCO) or secondary cataract formation, following intraocular lens implantation, is a significant complication affecting an estimated 28% of cataract patients. Matrix metalloproteinases (MMPs) have been demonstrated to play a role in the formation of anterior subcapsular cataracts and it has been shown that the presence of MMP inhibitors (MMPI) decreases subcapsular cataract formation ex vivo. Since the mechanisms responsible for anterior subcapsular cataract formation and posterior capsule opacification are similar, it is reasonable to suggest that MMP inhibitors may also mitigate PCO. One of the most effective ways of delivering the inhibitors may be from the implanted intraocular lens (IOL) material itself. In the current work, delivery of three different MMP inhibitors from silicone rubber as a model IOL material was examined. Loading methods were developed which allowed continuous release of active MMPI for periods of over 5 months in some cases. Reduced migration rates were observed in human lens epithelial cells in vitro, suggesting that an effect on PCO may be possible. While further studies are necessary to tune the systems to achieve the desired rates of release, this work demonstrates that delivery of MMPI from silicone IOL materials has the potential to decrease the incidence of PCO.

Impact of antibiotic resistance in the management of ocular infections: the role of current and future antibiotics

Purpose:

This article reviews the effects of the increase in bacterial resistance on the treatment of ocular infections.

Design:

Interpretive assessment.

Methods:

Literature review and interpretation.

Results:

Ocular bacterial infections include conjunctivitis, keratitis, endophthalmitis, blepharitis, orbital cellulitis, and dacryocystitis. Treatment for most ocular bacterial infections is primarily empiric with broad-spectrum antibiotics, which are effective against the most common bacteria associated with these ocular infections. However, the widespread use of broad-spectrum systemic antibiotics has resulted in a global increase in resistance among both Gram-positive and Gram-negative bacteria to a number of the older antibiotics as well as some of the newer fluoroquinolones used to treat ophthalmic infections. Strategies for the prevention of the increase in ocular pathogen resistance should be developed and implemented. In addition, new antimicrobial agents with optimized pharmacokinetic and pharmacodynamic properties that have low toxicity, high efficacy, and reduced potential for the development of resistance are needed.

Conclusions:

New antimicrobial agents that treat ocular infections effectively and have a low potential for the development of resistance could be a part of strategies to prevent the global increase in ocular pathogen resistance.