Clinical profile and outcome in Bacillus endophthalmitis

ACUTE POST-TRAUMATIC ENDOPHTHALMITIS SECONDARY TO BACILLUS PUMILUS / SAFENSIS

PURPOSE

To report a case of post-traumatic endophthalmitis secondary to Bacillus pumilus/safensis .

METHODS

Observational case report of a single patient.

RESULTS

A 62-year-old man presented with a traumatic corneal laceration because of baling wire while working on a sheep farm. Appropriate corneal laceration repair with injection of intravitreal antibiotics (ceftazidime, clindamycin, and vancomycin) was performed. A single organism, identified as B. pumilus or Bacillus safensis, was isolated from the vitreous aspirate. A subsequent pars plana vitrectomy, pars plana lensectomy, anterior capsulotomy, and fluid-air exchange was required because of severe inflammatory reaction from retained lens material, retinal edema, and vitreous opacities. Vision improved from hand motion to 20/60 at the three-month follow-up visit.

CONCLUSION

We describe a case of acute post-traumatic endophthalmitis secondary to B. pumilus/safensis.

Pyogenic spondylodiscitis in HIV-positive patients under antiretroviral therapy: A case series

Background: The incidence of pyogenic spondylodiscitis has been increasing in countries of Europe and North America, probably due to an increasing number of persons with risk factors for this infection. It is unclear whether HIV infection in the era of antiretroviral therapy (ART) increases the risk for spondylodiscitis. Method: We present 7 cases of pyogenic spondylodiscitis of the cervical, thoracic, and lumbar spine in six individuals living with HIV under ART with suppressed viral load. Results: All patients presented with severe non-radicular pain and elevated inflammatory markers. Diagnosis was confirmed by magnetic resonance imaging (MRI) scan and isolation of the pathogen. Staphylococcus aureus was the causative pathogen in five patients. One patient suffered from an infection with Klebsiella pneumoniae followed by a mixed infection with Cutibacterium acnes and Bacillus circulans 18 months later. All patients needed surgical intervention, and the mean duration of antibiotic treatment was 17 weeks (range 12-26). Five patients recovered fully, including two persons who also suffered from endocarditis. One patient died from multi-organ failure. Conclusion: Spondylodiscitis may be seen more frequently in persons living with HIV as they grow older and suffer from comorbidities which put them at risk for this infection. HIV physicians should be aware of the infection and its risk factors.

Consensus and controversies in the science of endophthalmitis management: Basic research and clinical perspectives

Infectious endophthalmitis is a severe intraocular infection caused by bacteria, or less commonly by fungi. It can occur after penetrating eye procedures, trauma, or the spread of infection from contiguous structures or via emboli from distant organs. Because of the time-critical nature of the treatment, endophthalmitis is treated with the clinical diagnosis and modified by the microbiological report of the intraocular contents. The current strategy for managing endophthalmitis relies on pre-clinical literature, case series, and one large multi-center randomized clinical trial on post-cataract surgery endophthalmitis. Culture-susceptibility of the microorganisms from undiluted vitreous guides the definitive treatment in non-responsive cases. Strategies to reduce the incidence of endophthalmitis after penetrating eye procedures have been developed concurrently with refined means of treatment. Despite these advances, outcomes remain poor for many patients. Although consensus articles have been published on managing endophthalmitis, treatment patterns vary, and controversies remain. These include (1) the use of newer methods for early and precise microbiological diagnosis; (2) the choice of intravitreal antibiotics; (3) the need for systemic therapy; (4) early and complete vitrectomy. Here, we review the current consensus and address controversies in diagnosing and managing endophthalmitis. This review is intended to familiarize physicians and ophthalmologists with different aspects of endophthalmitis management to make informed decisions.

C-X-C Chemokines Influence Intraocular Inflammation During Bacillus Endophthalmitis

Purpose

The purpose of this study was to explore the C-X-C chemokines CXCL2 and CXCL10 as potential anti-inflammatory targets for Bacillus endophthalmitis.

Methods

Bacillus endophthalmitis was induced in C57BL/6J, CXCL2^−/−, and CXCL10^−/− mice. At specific times postinfection, eyes were analyzed for Bacillus, retinal function, and inflammation. The efficacies of intravitreal anti-CXCL2 and anti-CXCL10 with or without gatifloxacin in B. cereus endophthalmitis were also assessed using the same techniques.

Results

Despite similar Bacillus growth in eyes of C57BL/6J, CXCL2^−/−, and CXCL10^−/− mice, retinal function retention was greater in eyes of CXCL2^−/− and CXCL10^−/− mice compared to that of C57BL/6J mice. Neutrophil migration into eyes of CXCL2^−/− and CXCL10^−/− mice was reduced to a greater degree compared to that of eyes of C57BL/6J mice. Infected CXCL2^−/− and CXCL10^−/− mouse eyes had significantly less inflammation compared to that of C57BL/6J eyes. Retinal structures in infected eyes of CXCL2^−/− mice were preserved for a longer time than in CXCL10^−/− eyes. Compared to untreated eyes, there was less inflammation and significant retention of retinal function in eyes treated with anti-CXCL2 and anti-CXCL10 with or without gatifloxacin.

Conclusions

For Bacillus endophthalmitis, the absence of CXCL2 or CXCL10 in mice resulted in retained retinal function and less inflammation. The absence of CXCL2 led to a better clinical outcome than the absence of CXCL10. The use of anti-CXCL2 and anti-CXCL10 limited inflammation during B. cereus endophthalmitis. These results highlight the utility of CXCL2 and CXCL10 as potential targets for anti-inflammatory therapy that can be tested in conjunction with antibiotics for improving treating Bacillus endophthalmitis.

Clinical presentations, microbiology and management outcomes of culture-proven endogenous endophthalmitis in India

Purpose:

To report the clinical presentation, microbiology, and management outcome of endogenous endophthalmitis in Indian patients.

Methods:

Retrospective chart review of culture-positive (vitreous/urine/blood) endogenous endophthalmitis cases treated in tertiary eye care facility in India was done.

Results:

The study included 173 eyes of 117 patients. Mean patient age was 25.41 ± 20.46 years (median 24 years). Pre-disposing systemic illness could not be elicited in 79 (67.63%) patients. Commonest predisposing systemic condition in patients where it could be detected (n = 79) was pyrexia of unknown origin (25/79 = 32.0%). Following treatment, 45 out of 173 (26.0%) eyes regained vision of ≥20/400. Commonest isolated organism from vitreous was Streptococcus pneumoniae (36 eyes, 20.8%) and fungi were isolated in 24 (13.8%) eyes, the commonest being Candida spp. (8/24, 33.33%). Favorable functional outcome was seen in 26% eyes and favorable anatomic outcome in 43% eyes. Those with an underlying systemic illness were older (P = 0.02), had greater urine culture positivity (P = 0.003), lesser vitreous culture positivity (0.001), greater gram negative etiology (P = 0.0006), and greater fungal etiology (P = 0.01) as compared to those cases without underlying systemic illness.

Conclusion:

Endogenous endophthalmitis in India often presents in young immunocompetent individuals without any underlying systemic illness and with negative blood or urine microbiologic work up. Underlying systemic illness leads to greater gram-negative and fungal etiology. Overall visual outcome is poor inspite of prompt management.

The cereus matter of Bacillus endophthalmitis

Bacillus cereus (B. cereus) endophthalmitis is a devastating intraocular infection primarily associated with post-traumatic injuries. The majority of these infections result in substantial vision loss, if not loss of the eye itself, within 12-48 h. Multifactorial mechanisms that lead to the innate intraocular inflammatory response during this disease include the combination of robust bacterial replication, migration of the organism throughout the eye, and toxin production by the organism. Therefore, the window of therapeutic intervention in B. cereus endophthalmitis is quite narrow compared to that of other pathogens which cause this disease. Understanding the interaction of bacterial and host factors is critical in understanding the disease and formulating more rational therapeutics for salvaging vision. In this review, we will discuss clinical and research findings related to B. cereus endophthalmitis in terms of the organism's virulence and inflammogenic potential, and strategies for improving of current therapeutic regimens for this blinding disease.

Factors affecting visual outcomes after treatment of infectious endophthalmitis in northeastern Thailand

Objective

To determine factors affecting visual outcomes after treatment of infectious endophthalmitis during 2012-2016 at a large referral eye center in northeastern Thailand.

Patients and methods

Medical charts of patients with a diagnosis of infectious endophthalmitis including demographic data, types of endophthalmitis, causative organisms, methods of treatment, anatomical, and functional outcomes were retrospectively reviewed. Factors associated with improved visual outcomes were analyzed.

Results

Four hundred and eleven patients (417 eyes) were recruited for the study. The three most common types were post-traumatic (44.53%), post-operative (31.87%), and endogenous endophthalmitis (17.52%). Vitreous cultures revealed causative organisms in 41.25%. Most common Gram-positive organisms were coagulase-negative Staphylococcus 30% (36/120), Bacillus spp. 20% (24/120), and Streptococcus pneumoniae 18.33% (20/120). Most common Gram-negatives were Pseudomonas spp. 24.32% (9/37), Klebsiella spp. 24.32% (9/37), and Enterobacter spp. 16.21% (6/37). Methods of treatment were medical treatment (18.71%) and surgical treatment (81.29%), including pars plana vitrectomy with or without silicone oil tamponade (62.59%) and destructive surgery (18.71%). After treatment, visual improvement was noted in 44.6%, stable vision in 18.47%, and worse vision in 36.93%. Factors associated with improved visual outcomes were post-operative endophthalmitis (P<0.001), coagulase-negative Staphylococcus (P=0.003), and initial visual acuity before treatment of hand motion or better (P=0.017).

Conclusion

Most infectious endophthalmitis patients were post-traumatic, post-operative, and endogenous. The most common method of treatment was pars plana vitrectomy. Treatment could improve visual outcomes and at least stabilize the vision in 63.07%. Factors associated with improved visual outcomes were types of endophthalmitis, causative organisms, and initial visual acuity before treatment.

CLINICAL PRESENTATION, MICROBIOLOGIC PROFILE AND FACTORS PREDICTING OUTCOMES IN BACILLUS ENDOPHTHALMITIS

PURPOSE

To describe the clinical presentation, microbiologic profile, and factors predicting outcomes in Bacillus endophthalmitis.

METHODS

Retrospective interventional case series. Eighty-six patients with culture-proven Bacillus endophthalmitis, from January 2001 to December 2015, underwent vitrectomy/vitreous biopsy and intravitreal antibiotic with or without steroid as appropriate. The undiluted vitreous biopsy was subjected to microbiologic evaluation. The duration of symptoms, presenting visual acuity, organisms isolated, influence of intravitreal dexamethasone with intravitreal antibiotics, and type of initial intervention were examined for any clinical and statistical correlation in terms of odds ratio with the final visual outcome.

RESULTS

Trauma was the commonest etiology (n = 75; 87.2%). Mixed infection with other bacteria was seen in 11 patients. All Bacillus species were sensitive to gentamicin followed by ciprofloxacin (n = 85; 98.83%) and vancomycin (n = 81; 94.18%). Odds in favor of a favorable visual outcome were seen with clinical treatment within 48 hours of the symptoms (OR 25.47, 95% CI 2.45-254.16, P = 0.006), better presenting vision (OR 31.21, 95% CI 2.96-323.64, P = 0.004), and absence of polymicrobial infection (OR 18.03, 95% CI 0.9-344.4, P = 0.05). Only 20% of all treated patients regained ambulatory vision, and one fifth of all of them developed phthisis.

CONCLUSION

Patients diagnosed with Bacillus endophthalmitis merit aggressive vitreous intervention guided by the culture-sensitivity report. Despite early and appropriate treat ment, the outcomes are generally poor.

Randomised controlled trial of prophylactic antibiotic treatment for the prevention of endophthalmitis after open globe injury at Groote Schuur Hospital

BACKGROUND/AIMS

Most post-traumatic acute infectious endophthalmitis occur within a week of open globe trauma, necessitating early antibiotic prophylaxis. There are few randomised studies that demonstrate the benefits of prophylactic antibiotics. This randomised controlled non-inferiority trial was aimed at determining the incidence of post-traumatic endophthalmitis using established intravenous/oral prophylaxis and comparing this to the incidence using oral antibiotics only.

METHODS

All adult patients admitted with open globe injury were included. Those with proven endophthalmitis, high-risk features, who underwent primary evisceration and those allergic to the trial antibiotics were excluded. Patients were randomised to receive either intravenous cefazolin and oral ciprofloxacin or oral ciprofloxacin and oral cefuroxime for 3 days from admission. Acute endophthalmitis was the primary outcome. Patients completed the study if they were followed up for 6 weeks post injury.

RESULTS

Three hundred patients were enrolled, with 150 in each arm. There were 99 exclusions. Seven patients developed endophthalmitis despite prophylaxis-2.0% (three cases) in the intravenous and oral arm, compared with 2.7% (four cases) in the oral-only arm-this difference was not statistically significant (p=0.703).

CONCLUSIONS

The incidence of endophthalmitis with prophylaxis was 2-3%. Selected patients with open globe injuries (without high-risk features) may receive either intravenous cefazolin and oral ciprofloxacin, or oral cefuroxime and oral ciprofloxacin as prophylaxis against acute endophthalmitis-the latter regimen has the advantage of shortening patients' hospital stays and reducing costs. Non-inferiority study-design limitations should be taken into account, however.

Current Perspectives of Prophylaxis and Management of Acute Infective Endophthalmitis

Endophthalmitis is an intraocular inflammatory condition which may or may not be caused by infective agents. Noninfectious (sterile) endophthalmitis may be attributable to various causes including postoperative retained soft lens matter or toxicity following introduction of other agents into the eye. Infectious endophthalmitis is further subdivided into endogenous and exogenous. In endogenous endophthalmitis there is hematogenous spread of organisms from a distant source of infection whereas in exogenous endophthalmitis direct microbial inoculation may occur usually following ocular surgery or penetrating eye injury with or without intraocular foreign bodies. Acute infective endophthalmitis is usually exogenous induced by inoculation of pathogens following ocular surgery, open-globe injury and intravitreal injections. More infrequently the infective source is internal and septicemia spreads to the eye resulting in endogenous endophthalmitis. Several risk factors have been implicated including immunosuppression, ocular surface abnormalities, poor surgical wound construction, complicated cataract surgery with vitreous loss and certain types of intraocular lens. Comprehensive guidelines and recommendations on prophylaxis and monitoring of surgical cases have been proposed to minimize the risk of acute endophthalmitis. Early diagnosis and prompt management of infective endophthalmitis employing appropriately selected intravitreal antibiotics are essential to optimize visual outcome.

BacillusPanophthalmitis with Posterior Extension to the Prechiasmatic Optic Nerve

A rare case ofBacilluspanophthlamitis with extension to the prechiasmatic optic nerve secondary to hematogenous spreading after intravenous drug use is presented. A 27-year-old man with a recent history of trauma to the left eye presented with severe left eye pain following a binge of intravenous drug use. Visual acuity (VA) was LP. On examination he had chemosis, proptosis, elevated intraocular pressure, and a complete hyphema. CT-scan identified preseptal swelling, but no evidence of any posterior extension of the anterior process or orbital fractures. Topical and systemic therapy were initiated. On follow-up clinical examination less than 12 hours after presentation he had signs of a keratitis with worsening ophthalmoplegia and repeat imaging demonstrated posterior extension to the prechiasmatic optic nerve. Shortly after the cornea ruptured with cultures growingBacillus. The patient underwent enucleation and has had no further progression of infection. To the best of our knowledge, this is the first report ofBacilluspanophthalmitis presenting with signs of trauma with posterior extension to the prechiasmatic optic nerve.

Bacillus cereus in personal care products: risk to consumers

Bacillus cereus is ubiquitous in nature and thus occurs naturally in a wide range of raw materials and foodstuffs. B. cereus spores are resistant to desiccation and heat and able to survive dry storage and cooking. Vegetative cells produce several toxins which on ingestion in sufficient numbers can cause vomiting and/or diarrhoea depending on the toxins produced. Gastrointestinal disease is commonly associated with reheated or inadequately cooked foods. In addition to being a rare cause of several acute infections (e.g. pneumonia and septicaemia), B. cereus can also cause localized infection of post-surgical or trauma wounds and is a rare but significant pathogen of the eye where it may result in severe endophthalmitis often leading to loss of vision. Key risk factors in such cases are trauma to the eye and retained contaminated intraocular foreign bodies. In addition, rare cases of B. cereus-associated keratitis (inflammation of the cornea) have been linked to contact lens use. Bacillus cereus is therefore a microbial contaminant that could adversely affect product safety of cosmetic and facial toiletries and pose a threat to the user if other key risk factors are also present. The infective dose in the human eye is unknown, but as few as 100 cfu has been reported to initiate infection in a susceptible animal model. However, we are not aware of any reports in the literature of B. cereus infections in any body site linked with use of personal care products. Low levels of B. cereus spores may on occasion be present in near-eye cosmetics, and these products have been used by consumers for many years. In addition, exposure to B. cereus is more likely to occur through other routes (e.g. dustborne contamination) due to its ubiquity and resistance properties of spores. The organism has been recovered from the eyes of healthy individuals. Therefore, although there may be a perceived hazard, the risk of severe eye infections as a consequence of exposure through contaminated near-eye cosmetics is judged to be vanishingly small. It is unlikely that more stringent microbiological standards for near-eye cosmetics will have any impact on the risk of severe eye infections caused by B. cereus, as these are not linked to use of personal care products.

Vancomycin-resistant Gram-positive bacterial endophthalmitis: epidemiology, treatment options, and outcomes

Background

The purpose of this study is to evaluate the microbiological profile and treatment outcomes of vancomycin-resistant Gram-positive bacterial endophthalmitis. Medical records of all patients with Gram-positive bacterial endophthalmitis resistant to vancomycin presenting between 1 January 2005 and 31 December 2010 were reviewed in this noncomparative, consecutive, retrospective case series. Favorable outcome was defined as a best-corrected visual acuity of ≥20/200.

Results

Out of 682 culture-positive endophthalmitis isolates, 448/682 (65.6%) were associated with Gram-positive bacteria. In vitro resistance to vancomycin was noted in 7/448 (1.56%). Three cases were posttraumatic, three were postoperative, and one was endogenous in origin. Four Bacillus isolates, two Staphylococcus isolates, and an Enterococcus isolate were resistant. Isolates resistant to vancomycin were sensitive in vitro to ciprofloxacin in 6/7 (86%) patients. Presenting visual acuity was light perception in all seven cases. Favorable outcome was achieved in only 1/7 (14.3%) cases.

Conclusions

Vancomycin-resistant endophthalmitis is uncommon and usually associated with poor visual outcome. Bacillus sp. is the most frequent Gram-positive bacteria resistant to vancomycin. Fluoroquinolones like ciprofloxacin may be considered as a useful alternative in vancomycin-resistant endophthalmitis.

Review of endogenous endophthalmitis during pregnancy including case series

Endogenous endophthalmitis during pregnancy is a rare condition with few reports of such infections in the peri- and post-partum period. We reviewed the literature on endogenous endophthalmitis in pregnancy and also report a series of four patients who presented to our institution from January 2011 to September 2011. We retrospectively reviewed four patients who developed endogenous endophthalmitis either during pregnancy (two patients) or in the post-partum period (two patients--one after abortion and one after normal term delivery). Presenting visual acuity ranged from finger counting at 3 m to no perception of light. Positive cultures included Bacillus mycoides (vitreous) and Klebsiella pneumoniae (urine). Vitrectomy was performed in three patients. In one patient, the vision improved to 20/20. On reviewing the literature and our experience we concluded that endogenous endophthalmitis related to pregnancy is a rare entity with visual prognosis generally being poor. Fluoroquinolones are best avoided. Cephalosporins and amphotericin B are generally the preferred drugs.

Endophthalmitis: A review of recent trends

Endophthalmitis is a feared complication of trauma, surgical procedures and septicemia. Although uncommon, its potential for significant visual loss is well recognized. Especially over the past decade, complicated surgeries and medical techniques have increased and seriously ill patients are being sustained in ever increasing numbers. New pathogens are being recognized and known ones reclassified thanks to advances in molecular analysis. Continuously evolving PCR methodologies also add a new dimension to the diagnosis of infectious endophthalmitis. As well, medical literature is now truly international, encompassing studies from around the world that expand our understanding of ocular infectious disease. This report reviews some of these changes as they relate to endophthalmitis and particularly to the spectrum of organisms involved.

Bacillus licheniformis as a cause of delayed-onset recurrent pseudophakic endophthalmitis-a rare case report

PURPOSE

To report a case of delayed-onset recurrent pseudophakic endophthalmitis caused by Bacillus licheniformis.

METHOD

Retrospective review of a case.

RESULTS

A 30-year-old lady (s/p pseudophakia 10 years) presented with features of acute endophthalmitis and a vision of light perception in the left eye. She had received 15 intravitreal injections and systemic corticosteroids earlier for similar complaints. A core vitrectomy and intravitreal antibiotics injection improved her vision to 20/70, although the symptoms recurred a week later. Intraocular lens explantation with a repeat vitrectomy and intravitreal antibiotics was performed. The vitreous/aqueous fluid on both occasions grew B. licheniformis sensitive to fluoroquinolones, vancomycin, and gentamicin. One year after the second surgery, her vision was 20/30 with a quiet eye.

CONCLUSION

This case shows that delayed-onset recurrent endophthalmitis after cataract extraction may be caused by Bacillus spp. and, despite sensitivity to most antibiotics, may require intraocular lens explantation for eradication of the infection.

A role for tumor necrosis factor-alpha in experimental Bacillus cereus endophthalmitis pathogenesis

PURPOSE

To determine the contribution of tumor necrosis factor-alpha (TNFalpha) in the pathogenesis of experimental Bacillus cereus endophthalmitis.

METHODS

Experimental B. cereus endophthalmitis was induced in wild-type control (B6.129F1) and age-matched homozygous TNFalpha knockout mice (TNFalpha(-/-), B6.129S6-Tnf(tm1Gk1)/J). At various times after infection, eyes were analyzed by electroretinography and were harvested for quantitation of bacteria, myeloperoxidase, proinflammatory cytokines and chemokines, and histologic analysis.

RESULTS

B. cereus replicated more rapidly in the eyes of TNFalpha(-/-) mice than in the eyes of B6.129F1 mice. Retinal function decreased more rapidly in TNFalpha(-/-) mice than in B6.129F1 mice. Retinal layers were not as structurally intact at 6 and 12 hours after infection in TNFalpha(-/-) eyes as in B6.129F1 eyes. Histologic analysis suggested less polymorphonuclear leukocyte (PMN) infiltration into the vitreous of TNFalpha(-/-) mice than of B6.129F1 mice. B6.129F1 eyes also had greater myeloperoxidase concentrations than did eyes of TNFalpha(-/-) mice. In general, concentrations of proinflammatory cytokines and chemokines (IL-1beta, KC, IL-6, and MIP-1alpha) were greater in eyes of TNFalpha(-/-) mice than of B6.129F1 mice.

CONCLUSIONS

TNFalpha is important to intraocular pathogen containment by PMNs during experimental B. cereus endophthalmitis. In the absence of TNFalpha, fewer PMNs migrated into the eye, facilitating faster bacterial replication and retinal function loss. Although greater concentrations of proinflammatory cytokines were synthesized in the absence of TNFalpha, the resultant inflammation was diminished, and an equally devastating course of infection occurred.

Toward improving therapeutic regimens for Bacillus endophthalmitis

PURPOSE

Bacillus cereus causes the most virulent and refractory form of endophthalmitis. The authors analyzed the effectiveness of early treatment with vancomycin or gatifloxacin, with or without dexamethasone, for experimental B. cereus endophthalmitis.

METHODS

Rabbit eyes were injected intravitreally with 100 colony-forming units of B. cereus. At 2, 4, or 6 hours after infection, eyes were injected intravitreally with 0.1 mL gatifloxacin (0.3%), vancomycin (1.0%), either antibiotic plus dexamethasone, dexamethasone alone (1.0%), or PBS. Eyes were analyzed by electroretinography, bacterial quantitation, and antibiotic penetration analysis. Drug toxicity toward Müller cells, retinal pigment epithelium, and cones was also analyzed.

RESULTS

Eyes treated at 2 hours with vancomycin or gatifloxacin, with or without dexamethasone, maintained higher ERG amplitudes than the dexamethasone alone and PBS control groups. Eyes treated with antibiotic plus dexamethasone at 6 hours had reduced retinal function compared to antibiotic treatment alone. With the exception of vancomycin with or without dexamethasone at 6 hours, all antibiotic treatments sterilized eyes. Only gatifloxacin reached aqueous concentrations greater than the minimal inhibitory concentration for B. cereus when measured at 8 hours. Neither gatifloxacin nor vancomycin was toxic to retinal cells in vitro.

CONCLUSIONS

Early intravitreal injection of vancomycin or gatifloxacin improved the therapeutic outcome of B. cereus endophthalmitis. The addition of dexamethasone to antibiotic treatment did not provide a therapeutic benefit over antibiotics alone and appeared to reduce the antibiotic efficacy of vancomycin 6 hours after infection. In this model, delay in treatment past 6 hours significantly reduced the potential for salvaging useful vision.

Endophthalmitis caused by Bacillus species

PURPOSE

To investigate clinical settings, management, and visual outcomes of endophthalmitis caused by Bacillus species and to review in vitro effectiveness of antibiotics commonly used against Bacillus species.

DESIGN

Retrospective, consecutive case series.

METHODS

Record review of all patients with endophthalmitis caused by Bacillus species treated at Bascom Palmer Eye Institute between January 1, 1990 and July 1, 2007. Antibiotic sensitivities were conducted on 21 of 22 isolates.

RESULTS

Twenty-two eyes of 22 patients met study inclusion criteria. Median follow-up was 18 months. Clinical settings included open globe injury (18 eyes), endogenous (two eyes), delayed-onset bleb-associated (one eye), and acute-onset postoperative (one eye). Twelve (67%) of 18 patients with open globe injuries had intraocular foreign bodies. Presenting visual acuity (VA) was hand movements or better in 13 (59%) patients. Initial treatment included pars plana vitrectomy and injection of antibiotics in 14 eyes (64%), vitreous tap and injection of antibiotics in seven eyes (32%), and evisceration in one eye (5%). Four (18%) patients received additional doses of intravitreal antibiotics; 16 (73%) underwent secondary surgical procedures. Eight (36%) patients achieved a final VA of 20/400 or better and four (18%) achieved a final VA of 20/60 or better. All patients received intraocular vancomycin and a cephalosporin or aminoglycoside. Systemic antibiotics were used in 18 (82%) patients. Fifteen (68%) isolates were Bacillus cereus. All isolates tested were sensitive to vancomycin, gentamicin, and five fluoroquinolones. Only three of 21 isolates were susceptible to penicillin and cephalosporins.

CONCLUSIONS

Endophthalmitis caused by Bacillus species often results in poor visual outcomes. In vitro antibiotic sensitivities indicate that vancomycin, aminoglycosides, and fluoroquinolones were effective against Bacillus isolates, whereas cephalosporins were relatively ineffective.

Bacterial endophthalmitis: therapeutic challenges and host-pathogen interactions

Endophthalmitis is an infection of the posterior segment of the eye that frequently results in loss of vision. This devastating result occurs despite prompt and often aggressive therapeutic and surgical intervention. Over the past decade, research has centered on determining the bacterial and host factors involved in this potentially blinding disease. The initial focus on the bacterial factors responsible for intraocular virulence has recently expanded into analysis the inflammatory response to infection, including the molecular and cellular interactions between the pathogen and host. This review discusses the epidemiology and therapeutic challenges posed by endophthalmitis, as well as recent findings from the analysis of interactions between the host and pathogen. Based on these findings, a model for the pathogenesis of endophthalmitis is presented. A more comprehensive understanding of the molecular and cellular interactions taking place between pathogen and host during endophthalmitis will expose possible therapeutic targets designed to arrest the infection and prevent vision loss.

Virulence factor profiles and antimicrobial susceptibilities of ocular bacillus isolates

Bacillus causes one of the most rapidly blinding intraocular infections: endophthalmitis. In this study, Bacillus spp. were isolated from ocular infection cases, taxonomically characterized by riboprint analysis, and screened for the presence of putative virulence factors. The ability of these isolates to kill retinal and corneal cells was examined, as were antibiotic susceptibility profiles. The majority of isolates belonged to the B. cereus taxonomic group of microorganisms and were identified as B. cereus (53%) or B. thuringiensis (26%). Toxins were identified in most B. thuringiensis and B. cereus isolates. Most B. cereus and B. thuringiensis killed corneal and retinal cells within 6 h. All isolates were susceptible to most antibiotics tested, with quinolones and vancomycin being the most potent. These findings represent the first report of B. thuringiensis as an important ocular pathogen, demonstrates the potential ocular toxicity of B. cereus and B. thuringiensis isolates, and identifies antibiotics whose efficacy against Bacillus were superior to those used clinically.

Fluorescent amplified fragment length polymorphism (FAFLP) genotyping demonstrates the role of biofilm-producing methicillin-resistant periocular Staphylococcus epidermidis strains in postoperative endophthalmitis

Background

An observational case series was used to study the virulence characteristics and genotypes of paired Staphylococcus epidermidis isolates cultured from intraocular samples and from periocular environment of patients with postcataract surgery endophthalmitis.

Methods

Eight S. epidermidis isolates were obtained from three patients (2 from patients #1 and 2 and 4 from patient #3) whose vitreous and/or anterior chamber (AC) specimens and preoperative lid/conjunctiva samples were culture positive. Cultures were identified by API-Staph phenotypic identification system and genotypically characterized by Fluorescent Amplified Fragment Length Polymorphism (FAFLP) and checked for their antimicrobial susceptibility. The isolates were tested for biofilm-production and methicillin-resistance (MR) by PCR amplification of icaAB and mecA gene respectively.

Results

Four out of eight S. epidermidis strains showed multiple drug resistance (MDR). All the eight strains were PCR positive for mecA gene whereas seven out of eight strains were positive for icaAB genes. In all three patients FAFLP typing established vitreous isolates of S. epidermidis strains to be indistinguishable from the strains isolated from the patient's conjunctival swabs. However, from patient number three there was one isolate (1030b from lid swab), which appeared to be nonpathogenic and ancestral having minor but significant differences from other three strains from the same patient. This strain also lacked icaAB gene. In silico analysis indicated possible evolution of other strains from this strain in the patient.

Conclusion

Methicillin-resistant biofilm positive S. epidermidis strains colonizing the conjunctiva and eyelid were responsible for postoperative endophthalmitis (POE).

High-resolution genotyping of Pseudomonas aeruginosa strains linked to acute post cataract surgery endophthalmitis outbreaks in India

BACKGROUND

Investigation of two independent outbreaks of post cataract surgery endophthalmitis identified the reservoir of epidemic strains of P. aeruginosa.

METHODS

Patient isolates cultured from vitreous fluid of all the nine cases and from the peripheral devices of phacoemulsification machine were subjected to high-resolution Fluorescent Amplified Fragment Length Polymorphism (FAFLP) analysis.

RESULTS

FAFLP based genotyping of the isolates confirmed nosocomial transmission. Although biochemical characterization and antibiotic susceptibility profiles grouped all the isolates together, FAFLP based genotyping revealed that, all the outbreak isolates were derived from 2 different strains, with independent origins. One group of isolates was traced to phacoprobe and the second one to the internal tubing system of the phacoemulsification machine used in cataract surgery. In silico analysis indicated possible evolution in both the clusters of P. aeruginosa isolates due to genetic polymorphisms. The polymorphisms were mapped to gene products (cell envelope, outer membrane proteins) possibly having significant role in pathogenesis.

CONCLUSION

The present study is probably the first one to apply FAFLP typing successfully to investigate outbreaks of postoperative endophthalmitis (POE) in an ophthalmic setting, which was able to identify the source, and helped to make rational decisions on sterilization procedures that halted more cases of infection in these hospitals.

Intraoperative explantation of two single-piece hydrophobic acrylic intraocular lenses due to surface deposits

PURPOSE

To report clinical, pathological, and laboratory analyses of two cases of single-piece hydrophobic acrylic intraocular lenses (IOLs), which presented with significant surface deposits during implantation.

METHODS

The lenses were implanted with the manufacturer's recommended injector (loaded with Viscoat and Healon GV, respectively). Immediately after injection into the anterior chamber, areas on the lenses' surfaces were covered by deposits, which could not be entirely removed by irrigation/aspiration. The lenses were explanted and replaced with lenses of the same design. They underwent gross analyses, light microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy for analysis of the elemental composition of the deposits. Liquid chromatography/mass spectroscopy was also performed to identify the presence of proteins.

RESULTS

The deposits on the first lens had a granular appearance, forming a homogeneous layer mostly on the posterior lens surface. Larger crystal-like deposits were present mostly on the anterior surface of the second lens. Elemental analyses of the deposits in both cases revealed the presence of peaks of sodium, chloride, phosphate, and potassium, in addition to the peaks of carbon and oxygen (normal constituents of the lens material). Only protein components normally found in the anterior chamber during surgery, such as haemoglobin and albumin, were identified.

CONCLUSIONS

The results obtained suggest that the deposits in both cases may have resulted from crystallization of the ophthalmic viscosurgical device normally used during the loading of the IOLs into the cartridges.

Infective endophthalmitis caused by Bacillus cereus after cataract extraction surgery

We describe a 72-year-old Chinese man who developed fulminant Bacillus cereus endophthalmitis 36 h after an uneventful surgery for cataract extraction. Clinical progression of disease was extremely rapid, in spite of early vitrectomy and intravitreal injection of antibiotics. Results of Gram staining showed gram-positive bacilli, and the culture was positive for B. cereus. Endophthalmitis is rare after cataract surgery (cumulative probability within 1 year, approximately 0.08%), and cases caused by B. cereus are even less common. The prognosis and plan of treatment are discussed.