Bacillus-induced endophthalmitis: new series of 10 cases and review of the literature

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.

Effect of temperature and soluble solid on Bacillus subtilis and Bacillus licheniformis spore inactivation and quality degradation of pineapple juice

Bacillus subtilis and Bacillus licheniformis spores can survive processing temperatures used in the thermal processes of high-acid foods. Therefore, this study investigated the thermal inactivation of B. subtilis and B. licheniformis spores in pineapple juice at different temperatures (85-100°C) and soluble solids (SS, 11-30°Brix). The quality of juices and microbial loads after the thermal treatments during storage at 4 °C for 35 days was then checked. A linear decrease in D-value was observed with increasing temperature of treatment. Furthermore, the D-values determined in pineapple juice were: D_90°C=13.2 ± 0.5 mins, D_95°C = 6.8 ± 0.9 mins and D_100°C = 2.1 ± 1.7 mins for B. subtilis spores, and D_85°C = 16.6 ± 0.4 mins, D_90°C = 7.6 ± 0.5 mins and D_95°C = 3.6 ± 1.5 min, for B. licheniformis. Generally, the susceptibility of the bacteria to soluble solid change was affected by the interaction between temperature, SS and strain. In addition, pasteurization processes of ≥95°C for ≥33.8 mins was needed to ensure a recommended 5-log reduction of B. subtilis spores and limit vitamin C degradation of pineapple juice within three-week of storage at 4 °C.

Posttraumatic Bacillus cereus Endophthalmitis: Clinical Characteristics and Antibiotic Susceptibilities

Purpose

To report the clinical characteristics, antibiotic susceptibilities, and visual outcomes of patients with posttraumatic endophthalmitis caused by Bacillus cereus.

Methods

In this retrospective, noncomparative case series, the medical records of eyes with culture-proven Bacillus cereus endophthalmitis treated from January 2016 to December 2019 at a referral center were reviewed. Clinical features, antibiotic susceptibilities, and visual outcomes were assessed.

Results

A total of 19 eyes of 19 patients were identified. Three patients progressed to orbital cellulitis. Vitrectomy was performed in 13 eyes, and 11 required silicone oil tamponade. Finally, seven eyes underwent silicone oil removal surgery during follow-up. Only two patients retained a visual acuity better than FC. Four patients underwent evisceration, and three patients had NLP. The cultured Bacillus cereus was sensitive to levofloxacin, ofloxacin, tobramycin, and neomycin at 100%.

Conclusions

The visual outcomes of posttraumatic Bacillus cereus endophthalmitis were generally poor regardless of the prophylactic and therapeutic measures administered. Vitrectomy combined with silicone oil tamponade could help to save the eyeball. Bacillus cereus has a good susceptibility to ofloxacin, levofloxacin, tobramycin, and neomycin; therefore, fluoroquinolones and aminoglycosides can be used to treat Bacillus cereus infection.

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.

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.

Posttraumatic Endophthalmitis in children: Epidemiology, Diagnosis, Management, and Prognosis

Pediatric posttraumatic endophthalmitis presents with great complexities and challenges arising due to delayed presentation, difficulty in eliciting an accurate history, or trauma with unusual and highly contaminated objects. The possibility of initial misdiagnosis as panuveitis, metastatic endophthalmitis, and masquerade syndrome is also very high, which results not only in several unwarranted investigations being performed, but also a delay in the initiation of treatment. The standard treatment remains primary repair of the wound, intravitreal therapy with broad spectrum antibiotics, and parsplana vitrectomy. Despite appropriate intervention, visual outcome in children with posttraumatic endophthalmitis is dampened by additional factors like poor compliance with postoperative instructions and high risk of amblyopia. Hence, it is important to recognize that posttraumatic endophthalmitis in children differs from that in adults in several ways. We made a very tailored effort to review the published literature pertaining to posttraumatic endophthalmitis in children and herein present the results of our search.

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.

Recurrent sepsis due to bacillus licheniformis

Bacillus licheniformis is recognized as a human pathogen causing infections, mainly in immunocompromised patients. We present a case of sepsis in an immunocompetent patient, caused by B. licheniformis. This case is of particular interest because the patient had no history of any immune deficiency and the disease did not respond to antibiotic treatment.

Delayed-onset endophthalmitis associated with Ex-PRESS mini glaucoma shunt®

The authors describe a 92-year-old man who developed delayed-onset endophthalmitis secondary to Bacillus sp. in his left eye 3 years after placement of an Ex-PRESS mini glaucoma shunt (Optonol Ltd., Neve Ilan, Israel). Seidel testing was positive over the Ex-PRESS mini glaucoma shunt. The patient underwent vitreous tap followed by intravitreal injections of vancomycin (1 mg/0.1 mL), ceftazadime (2.25 mg/0.1 mL), and dexamethasone (0.4 mg/0.1 mL), along with subconjunctival injection of vancomycin and tobramycin. The last recorded visual acuity was 3/200 in the left eye. With a 1-month follow-up, this case illustrates successful treatment with a vitreous tap and injection of intravitreal antibiotics. Vitrectomy and removal of the Ex-PRESS mini glaucoma shunt were not performed.

Treatment of experimental Bacillus cereus endophthalmitis using intravitreal moxifloxacin with or without dexamethasone

PURPOSE

To evaluate the effects of intravitreal moxifloxacin with or without dexamethasone on experimental Bacillus cereus endophthalmitis.

METHODS

The right eyes of 21 New Zealand albino rabbits weighing 2-3 kg were used in this study. Each eye was inoculated with 1×10(6) colony-forming units of B. cereus microorganisms via intravitreal injection into the vitreous cavity, and an experimental model of B. cereus endophthalmitis was formed. The rabbits were separated into 3 groups: Group 1 was given 0.1 mL of balanced saline solution intravitreally, group 2 was given 50 μg of moxifloxacin, and group 3 was given 50 μg of moxifloxacin plus 400 μg of dexamethasone 24 h after the inoculation. Vitreous aspirates were taken for microbiological examination on the 3rd day. Clinical inflammation scores were evaluated on days 1, 7, and 14. The rabbits were killed on the 14th day, and the eyes were enucleated for histopathological examination.

RESULTS

On the 7th day, only the vitreous scores of the treatment groups were significantly low compared with those of the control group (P<0.05). On day 14, the clinical scores of vitreous inflammation were 2.43±0.79, 1.43±0.53, and 1.29±0.49 in Groups 1, 2, and 3, respectively. The clinical scores of the treatment groups were significantly lower compared with those of the control group on day 14 (P<0.05). Histopathological scores were 2.43±0.79, 1.43±0.53, and 1.43±0.79 for the iris and 2.14±0.69, 1.57±0.53, and 1.14±0.38 for the vitreous in Groups 1, 2, and 3, respectively. Apart from the conjunctiva, the histopathological scores of the other tissues in the treatment groups were significantly lower compared with those of the control group (P<0.05). No significant differences were found in the histopathological or clinical scores among the treatment groups (P>0.05). Microbiological scores at day 14 were 151±6.43, 125.43±13.44, and 131.14±16.99 for Groups 1, 2, and 3, respectively. The microbiological scores of the treatment groups were significantly lower compared with those of the control group (P<0.05).

CONCLUSIONS

Intravitreal moxifloxacin injection is effective in experimental B. cereus endophthalmitis. The addition of intravitreal dexamethasone may not significantly affect treatment efficacy.

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.

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.

Bacillus cereus food poisoning and its toxins

The genus Bacillus includes members that demonstrate a wide range of diversity from physiology and ecological niche to DNA sequence and gene regulation. The species of most interest tend to be known for their pathogenicity and are closely linked genetically. Bacillus anthracis causes anthrax, and Bacillus thuringiensis is widely used for its insecticidal properties but has also been associated with foodborne disease. Bacillus cereus causes two types of food poisoning, the emetic and diarrheal syndromes, and a variety of local and systemic infections. Although in this review we provide information on the genus and a variety of species, the primary focus is on the B. cereus strains and toxins that are involved in foodborne illness. B. cereus produces a large number of potential virulence factors, but for the majority of these factors their roles in specific infections have not been established. To date, only cereulide and the tripartite hemolysin BL have been identified specifically as emetic and diarrheal toxins, respectively. Nonhemolytic enterotoxin, a homolog of hemolysin BL, also has been associated with the diarrheal syndrome. Recent findings regarding these and other putative enterotoxins are discussed.

Liver abscess due to Bacillus cereus: a case report

Bacillus cereus is a food-borne pathogen that causes a self-limiting gastroenteritis. We describe the case of a 72-year-old woman admitted to our hospital because of acute abdominal colic pain. Over a 2-day period, her clinical condition deteriorated rapidly, with the appearance of acute abdomen. Computed tomography investigation of the abdomen showed a liver abscess (diameter approximately 3 cm). At laparotomy, the abscess was found to be ruptured to the free peritoneal cavity. The final clinical diagnosis was acute peritonitis due to a ruptured liver abscess. Bacillus cereus was isolated from culture of the pus. Up to now, no case of liver abscess due to this organism has been reported.

Post traumatic polymicrobial endophthalmitis, including Neisseria subflava

DESIGN

To report the second known case of post-traumatic endophthalmitis caused by Neisseria subflava.

DESIGN

Interventional case report.

METHODS

A two-year-old child with post-traumatic corneal laceration and uveal prolapse required medical and surgical therapy for endophthalmitis caused by multiple organisms including N. subflava.

RESULTS

After aggressive therapy, patient had a favorable outcome without vision compromise.

CONCLUSIONS

As there is still not a standard protocol for therapy for post-traumatic endopthalmitis, we recommend the use of broad-spectrum antibiotics via intravitreal, intravenous, and topical routes. Consideration of typical and unusual bacteria that have been reported to cause endopthalmitis, as well as the source of injury, should guide antibiotic choice.

Endogenous bacterial endophthalmitis: a 17-year prospective series and review of 267 reported cases

Endogenous bacterial endophthalmitis is a rare but serious condition that occurs when bacteria cross the blood-ocular barrier and multiply within the eye. We provide an overview of endogenous bacterial endophthalmitis by reviewing 267 reported cases and integrating this with our experience of an additional 19 cases. The majority of patients with endogenous bacterial endophthalmitis are initially misdiagnosed and many have an underlying disease known to predispose to infection. This condition is often previously undiagnosed. Blood cultures are the most frequent means of establishing the diagnosis. The most common Gram positive organisms are Staphylococcus aureus, group B streptococci, Streptococcus pneumoniae,and Listeria monocytogenes. The most common Gram negative organisms are Klebsiella spp., Escherichia coli, Pseudomonas aeruginosa, and Neisseria meningitidis. Gram negative organisms are responsible for the majority of cases reported from East Asian hospitals, but Gram positive organisms are more common in North America and Europe. The visual outcome is poor with most cases leading to blindness in the affected eye. Many patients have extraocular foci of infection, with an associated mortality rate of 5%. The outcome of endogenous bacterial endophthalmitis has not improved in 55 years and clinicians need to have a high level of awareness of this commonly misdiagnosed condition.

Ocular manifestations of injection drug use

Injection drug use can result in a variety of severe ocular conditions. Hematogenous dissemination of various fungi and bacteria may produce endophthalmitis with resultant severe visual loss. Retinal arterial occlusive disease may result from talc and other particulate emboli. Most commonly, life-threatening systemic diseases such as endocarditis and HIV infection secondarily affect the eye. Because many of these conditions may result in blindness if untreated, accurate diagnosis and prompt initiation of therapy are essential.

Clinical profile and outcome in Bacillus endophthalmitis

OBJECTIVE

To study the clinical presentation, microscopic and organismal culture correlation of vitreous, and species-specific outcome in Bacillus endophthalmitis

DESIGN

Retrospective noncomparative case series.

INTERVENTION

Thirty-one culture proven Bacillus endophthalmitis patients between January 1991 and February 1998 underwent vitrectomy and intravitreal antibiotic injection. Lensectomy was combined when considered essential, and on a few occasions intravitreal dexamethasone was added. The patients also received topical and systemic antibiotics. The undiluted vitreous biopsy was the source for microbiologic evaluation (microscopy and culture sensitivity).

MAIN OUTCOME MEASURES

The duration of symptoms, the presenting visual acuity, and influence of intravitreal dexamethasone with intravitreal antibiotics were examined for any statistical correlation with the final visual acuity.

RESULTS

Trauma was the major cause of infection. Vitreous biopsy microscopy demonstrated gram-positive bacillus in 28 of 31 cases, and polymicrobial infection was seen in 12 instances. All Bacillus species were sensitive to gentamicin, followed by vancomycin and ciprofloxacin. Clinical treatment within 7 days of symptoms, use of intravitreal vancomycin, and absence of polymicrobial infection were associated with better visual outcome.

CONCLUSIONS

With appropriate treatment that essentially consists of vitrectomy and intravitreal antibiotics, patients with Bacillus endophthalmitis are likely to benefit in many instances. Gram-positive bacilli detected on vitreous microscopy should be empirically treated as Bacillus species unless otherwise proved.

The management of corneal trauma: advances in the past twenty-five years

Over the past quarter century, advances in our understanding of corneal anatomy, physiology, and wound healing have all played an integral role in the management of corneal trauma. As the etiologies of corneal trauma have changed, so has our understanding of the impact of injury on corneal function as it relates to visual rehabilitation. Numerous new classes of antibiotics, antiinflammatory agents, and tissue adhesives have emerged. Occlusive therapy has advanced from simple pressure patching bandage soft contact lenses and collagen shields. Surgical instrumentation, operating microscopes, viscoelastic substances, and suture materials have all improved the outcomes of corneal trauma repair. Improved understanding of the refractive properties of the cornea through topography and alternative suture techniques has helped us restore the natural corneal curvature and visual outcomes. Consequently, in the last quarter of this century our therapeutic approaches to cornea trauma, both medical and surgical, have improved.

Epidemic Bacillus endophthalmitis after cataract surgery II: chronic and recurrent presentation and outcome

OBJECTIVE

To report the clinical outcome of chronic Bacillus endophthalmitis after cataract surgery.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Five eyes of five patients with late-onset or recurrent inflammation after exposure to bacteria-contaminated viscoelastic material were studied.

INTERVENTION

Repeated vitrectomies, wide excision of the remnant posterior capsule, and intravitreal injections of antibiotics in five patients. Eventual explantation of the intraocular lens in four patients.

MAIN OUTCOME MEASURES

Final visual acuities and results of microbiologic studies of aqueous and vitreous specimens as well as pathologic studies using hematoxylin-eosin, Gram, and periodic acid-Schiff (PAS) stain of explanted capsular remnants were obtained.

RESULTS

Final visual acuity of 20/40 or better was obtained in three patients. Bacillus species were grown from two cases. PAS- and Gram-positive microorganisms were identified in the capsular tissue in three of four patients who had explantation of the intraocular lens.

CONCLUSIONS

A chronic form of Bacillus endophthalmitis is described for the first time. The clinical outcome is similar to chronic endophthalmitis caused by other organisms.

Enucleation

The three most common indications for enucleation are intraocular malignancy, trauma, and a blind, painful eye. Recommending enucleation is one of the most difficult therapeutic decisions in ophthalmology. In some cases of malignancy, cryotherapy, laser photocoagulation, diathermy, chemotherapy, and radiation therapy may be viable alternatives to surgery. When surgery is chosen, evisceration or exenteration may be alternatives to enucleation. Once the decision is made to perform enucleation or evisceration, the surgeon must choose from several types of implants and wrapping materials. These devices can be synthetic, autologous, or eye-banked tissues. With certain implants, the surgeon must decide when and if to drill for subsequent peg placement. In this review, the authors discuss choices, techniques, complications, and patient consent and follow-up before, during, and after enucleation. Controversies and results of the Controlled Ocular Melanoma Study are summarized.

Endophthalmitis

Endophthalmitis is an inflammatory reaction of intraocular fluids or tissues. Infectious endophthalmitis is one of the most serious complications of ophthalmic surgery. Occasionally, infectious endophthalmitis is the presenting feature of an underlying systemic infection. Successful management of infectious endophthalmitis depends on timely diagnosis and institution of appropriate therapy. Recognition of the different clinical settings in which endophthalmitis occurs and awareness of the highly variable presentation it may have facilitate timely diagnosis. Biopsy of intraocular fluid/tissue is the only method that permits reliable diagnosis and treatment. The different presenting clinical settings, a rational approach to diagnosis (i.e., when, what, and how to biopsy), and the treatment of infectious endophthalmitis are reviewed.

Endophthalmitis following penetrating eye injuries

Postinjury endophthalmitis is the eye infection with the worst prognosis. A retrospective 9-year study was made of penetrating eye injuries, with an analysis of the incidence of infection and its relation to the type of wound and the presence of intraocular foreign bodies. There were 403 cases of penetrating eye injury; of these, 233 affected the cornea and 170 involved the posterior pole. Intraocular foreign bodies were present in 40 cases. Endophthalmitis developed in 4.2% of cases (17/403), and was more common in patients with posterior pole involvement (7%) than in purely corneal trauma (2.1%) (p = 0.03, Chi-square). Infection was in turn more frequent in the presence of intraocular foreign bodies (15%) (p = 0.17, Chi-square). Staphylococcus epidermidis was the most common cause (23.4%), while in three cases (17.6%) mixed infection was detected. The visual results were evisceration or non-perception of light in 82.3% of cases.

Host/parasite interactions in bacterial endophthalmitis

Bacterial infections within the eye arise as complications of intraocular surgery, penetrating injury, or hematogenous spread from distant anatomical sites. Because: 1) the interior surfaces of the eye are lined with sensitive, nonregenerating tissues, 2) the inner chambers of the eye are relatively sequestered from circulating immunological components, 3) the integrity of blood-ocular barriers provides poor penetration of systemically administered antibiotics, and 4) aqueous and vitreous humor represent rich, relatively acellular culture media; endophthalmitis often progresses rapidly and total loss of vision frequently results. Years of clinical experience have shown that current therapies for endophthalmitis, including antimicrobials, antiinflammatory agents, and vitrectomy, are frequently unsuccessful in ameliorating destruction of intraocular tissues. While bacterial and host factors were thought to play key roles in the course and severity of endophthalmitis, it is only recently that their contributions have been experimentally defined. Molecular-based techniques are gaining increased use in the study of infectious eye diseases. Current findings regarding the host/parasite interactions within the eye are reviewed, and a resulting integrative model of the natural course of endophthalmitis proposed. A molecular-level understanding of the roles of both bacterial and host factors during endophthalmitis will likely reveal potential targets for therapeutic intervention aimed at salvaging vision.

Experimental Bacillus cereus post-traumatic endophthalmitis and treatment with ciprofloxacin

BACKGROUND

Bacillus species remain an important cause of post-traumatic endophthalmitis, often causing permanent visual loss.

METHODS

Twenty two rabbits were used to evaluate the clinical and histological findings of Bacillus cereus experimental post-traumatic endophthalmitis. Eyes that had received a scleral laceration and surgical repair were inoculated with Bacillus cereus. Thirty four other rabbits were used to evaluate the efficacy of intravitreal ciprofloxacin in treating experimental disease.

RESULTS

Animals developed a post-traumatic endophthalmitis that closely mimicked human disease, characterised by a rapidly progressive and destructive endophthalmitis. Histological evaluation revealed retinal detachment, retinal necrosis, and the infiltration of inflammatory cells into the subretinal space. Intravitreal ciprofloxacin (100 micrograms) prevented the development of disease when given 1 hour and 6 hours after trauma and inoculation.

CONCLUSIONS

Clinical and histological examination of experimental Bacillus cereus post-traumatic endophthalmitis suggests that retinal detachment and retinal necrosis play important roles in visual loss. Ciprofloxacin may be of benefit in the management of certain intraocular infections following penetrating injury.

Useful visual outcomes after treatment of Bacillus cereus endophthalmitis

PURPOSE

Bacillus cereus endophthalmitis occurring after penetrating ocular trauma has been almost always associated with a poor visual outcome. The purpose of our study was to review and report patients who had useful visual acuity outcomes.

METHODS

The study group consisted of five patients from a single medical center with penetrating ocular trauma and endophthalmitis caused by B. cereus. The study population was derived from a review of the microbiology records, clinical records, and operative reports of patients with culture-proven, post-traumatic endophthalmitis over a 15-year period. Patients were only included if the final visual acuity outcomes were 20/200 or better.

RESULTS

All five patients had penetrating ocular injuries, and four patients had a retained intraocular foreign body. Endophthalmitis was diagnosed preoperatively in three patients and intraoperatively in two patients. All patients underwent pars plana vitrectomy and injection of intravitreal and periocular antibiotics. Postoperatively, a rhegmatogenous retinal detachment developed in three patients between 4 weeks and 12 months after the injury (average, 19 weeks); all retinal detachments were reattached with additional vitreoretinal surgery. Final postoperative visual acuities were 20/200 (two patients), 20/30 (one patient), and 20/25 (two patients). The postoperative follow-up time interval ranged from 12 months to 30 months (average, 19.2 months).

CONCLUSION

The current series adds further support to the observation that certain eyes with post-traumatic B. cereus endophthalmitis may be associated with preservation of anatomic integrity and restoration of useful visual acuity.

Paediatric post-traumatic endophthalmitis

AIMS

A retrospective analysis of children with post-traumatic endophthalmitis was performed to determine if microbiological differences exist between this disease in the paediatric population compared with this disease in adults.

METHOD

Twelve cases of post-traumatic endophthalmitis in children were analysed to determine characteristics of this disease in youth. Patient ages varied from 18 months to 13 years; the mean age was 8 years. Gram positive organisms were isolated in eight eyes, Gram negative organisms from four eyes, fungus from one eye, and negative cultures in three eyes. The most common isolates were streptococcal species (56.6%) and staphylococcal species (22.2%). Vitrectomy was performed on eight (66.7%) eyes.

RESULTS

Visual acuity of 20/200 or better was obtained in eight eyes (66.7%). Three eyes had vision less than 5/200. One eye developed phthisis bulbi. Nine (75%) patients were younger than 10 years of age, and six (66.7%) of these nine obtained a final visual acuity of 20/200 or better.

CONCLUSION

Useful vision can be obtained in children with post-traumatic endophthalmitis with early, aggressive treatment. The microbiology of paediatric post-traumatic endophthalmitis differs from adult disease with streptococcal species as the most common infecting organisms.

Microbial keratitis in patients infected with the human immunodeficiency virus

BACKGROUND

Posterior segment complications of systemic infection with the human immunodeficiency virus (HIV) are well recognized. The anterior segment complications often are, however, overlooked. The author treated 20 episodes of nonherpetic infectious keratitis in 17 eyes of 13 patients infected with HIV who presented between August 1990 and May 1994.

METHODS

Review of records.

RESULTS

Nine patients were women, and four were men. Mean age was 35.2 years. The keratitis was bilateral in four patients, polymicrobial in four, and recurrent in two. The most common infecting organism was Candida albicans (5 eyes), a rare cause of keratitis in immunocompetent individuals. Other organisms included Staphylococcus aureus in four eyes, Staphylococcus epidermidis in four, Bacillus sp in two, and one each Pseudomonas aeruginosa, alpha-hemolytic Streptococcus, Micrococcus sp, and Capnocytophaga sp. Seven eyes retained 20/30 or better visual acuity after treatment, eight had visual acuity of 20/50 or worse, and two were eviscerated. Classic predisposing factors for infectious keratitis were found in only two patients and included contact lens wear and atopy in one patient each. Twelve patients had a history of intravenous drug abuse.

CONCLUSION

Infectious keratitis should be recognized as a complication of systemic HIV infection, especially in the context of drug abuse. The prognosis for recovery of vision in these patients often is poor.

Use of vancomycin in vitrectomy infusion solution and evaluation of retinal toxicity

The retinal toxicity of vancomycin in infusion solution used in vitrectomy and lensectomy was investigated in rabbit eyes by means of electroretinography and histologic study (light microscopy). Concentrations of 8 micrograms/ml, 16 micrograms/ml, and 32 micrograms/ml of vancomycin in balanced salt solution caused no abnormal ERG or histologic changes. However, ERG amplitude depression and abnormal histologic changes occurred when the concentration of 100 micrograms/ml of vancomycin was used.

Ocular injuries caused by magpies

This paper presents a series of six patients with ocular injuries resulting from magpie attacks. Five cases involved children. In two cases the penetration was overlooked initially. In one case the keratitis was caused by Bacillus cereus. Full ophthalmic examination, including indirect ophthalmoscopy and microbiological studies, must be undertaken initially to identify unrecognised eye injuries and to prevent the possible sight-threatening complications of vitreal fibrosis with subsequent retinal detachment or endophthalmitis.

Endophthalmitis at the Bristol Eye Hospital: an 11-year review of 47 patients

We reviewed data from 47 patients who were treated for endophthalmitis at our hospital during the 11-year period 1980-90. The most common clinical features were hypopyon (75%), diminished vision (72%), ocular pain (68%), discharge (57%), corneal oedema (51%), conjunctival injection (49%), abnormal red reflex (34%), corneal ulcer (32%) and corneal perforation (6%). A total of 54 isolates were obtained from 41 (87%) of the 47 patients. Gram-positive bacteria were more common (72%), than Gram-negative organisms (22%). Two cases were due to fungi, and herpes simplex virus was isolated from one case. The two most common Gram-positive organisms were coagulase-negative staphylococci (25%), and Staphylococcus aureus (11%), while Pseudomonas aeruginosa predominated among the Gram-negative bacteria isolated (15%). Mixed bacterial species were obtained from 29% of the infected patients, including one from whom Vibrio fluvialis was isolated. Predisposing factors included ocular surgery (60%)--mostly for cataract extraction (47%), penetrating trauma (15%) and periocular (15%) or systemic (11%) infections. All patients received antibiotics (generally chloramphenicol and/or a beta-lactamase-stable penicillin plus an aminoglycoside) prior to culture, when treatment was adjusted according to specific aetiological agents. Seventy-nine per cent of patients received topical or systemic steroids. Vitrectomy (diagnostic and therapeutic) was performed on 21% of patients. Sixty-three per cent of culture-positive patients lost vision (no perception of light) in the affected eye, compared to 17% of culture-negative cases (P < 0.05 Fisher exact test). Similarly, a better visual outcome (acuity of 6/12 or better) was associated with coagulase-negative staphylococcal infection than with streptococcal or fungal infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Criteria for intravitreal antibiotics during surgical removal of intraocular foreign bodies

Published opinion supports the early use of prophylactic antibiotics soon after presentation of a potentially contaminated intraocular foreign body (IOFB) in the posterior segment, preferably within 12 hours of trauma when the visual acuity is still good. Recommended treatment includes topical, subconjunctival, parenteral and especially intravitreal antibiotic therapy to reduce the chance of endophthalmitis. Intravitreal therapy should include gentamicin with vancomycin or clindamycin to cover Bacillus spp., since this organism is responsible for half the endophthalmitis cases and produces beta-lactamase giving resistance to penicillins and cephalosporins. Intravitreal therapy is important because systemic and topical antibiotics do not penetrate the globe in sufficient concentration to control a fulminant infection associated with damaged tissue. Early therapy is essential, as delaying treatment until endophthalmitis occurs is less likely to save useful vision. All vitreous aspirated, plus pus if present, and the IOFB should be cultured for bacteria and fungi to identify pathogens and gain antibiotic sensitivities. The prevention of IOFB-associated endophthalmitis requires early recognition of the IOFB and enthusiastic antibiotic therapy at the time of its removal.

Intravitreal penetration of oral ciprofloxacin in humans

Nineteen patients about to undergo elective vitreous surgery received 1 oral dose of 750 mg of ciprofloxacin before surgery. Specimens of serum and vitreous were collected 90 minutes to 18 hours after drug administration and were assayed for antibiotic content with a microbiologic disk agar technique. From 4 hours and 50 minutes to 16 hours and 50 minutes after a single oral dose, ciprofloxacin reached intravitreal levels above its minimal inhibitory concentration for 90% of Staphylococcus epidermidis, Bacillus species, and Enterobacteriaceae. However, intravitreal levels never exceeded the MIC90 for Staphylococcus aureus and Pseudomonas.

Experimental postoperative endophthalmitis

Various inocula of vancomycin-sensitive E faecalis (EF01), S aureus (SA02), S epidermidis (SE03), and B cereus (BC04), were intravitreally inoculated into an aphakic rabbit model with and without vancomycin, with or without vitrectomy. A summation average of the clinical response mean scores of various inocula (10(3), 10(5), 10(7) cfu) in the absence of therapy ranked these etiologic agents in the order of severity as SE03 (1.4), BC04 (1.8), EF01 (2.3), and SA02 (2.8). These favorably compared with the histopathology cavitary/noncavitary mean scores in increasing order of severity: SE03 (1.7/0.6), BC04 (1.7/0.9), EF01 (2.4/1.1), and SA02 (2.5/1.5), compared with control eyes (1.1/0.4). If the inoculum was increased to 10(7) cfu, SE03 (2.4/0.9) and BC04 (2.8/2.0) could equate EF01 and SA02. Treatment with 1 mg of vancomycin, with or without vitrectomy, did not significantly alter the overall inflammatory response to these four endophthalmitis isolates. No treatment was necessary to achieve > 99.9% killing effect by 72 hours when testing BC04, while any of the treatment modalities during 72 hours achieved 99.9% killing effect when testing SE03. No treatment modality achieved a 99.9% killing effect when testing EF01 or SA02. No single in vitro result could predict the in vivo microbiologic behavior of this model. Further research is needed to better understand the role of antiinflammatory agents, multiple drug therapy, and multiple-injection single-drug therapy with or without vitrectomy, and their impact on the inflammatory response in the aphakic model, to better treat endophthalmitis and thus improve visual prognosis.

Antibiotic therapy for Bacillus species infections

We reviewed 36 cases of culture-proven Bacillus species ocular infections occurring between September 1974 and December 1989. Kirby-Bauer disk sensitivities were available in 34 of the 36 cases (95%). All Bacillus species isolates were sensitive to the aminoglycoside antibiotics (N = 34) and to vancomycin hydrochloride (N = 32); resistance to clindamycin was found in four of 18 (22%) of tested isolates. Although B. cereus was uniformly sensitive to these antibiotics, resistance to clindamycin occurred in four cases in the non-B. cereus group. The microbroth dilution technique confirmed the Kirby-Bauer data. The aminoglycosides were uniformly effective, but the cephalosporins (first, second, and third generation drugs) were consistently ineffective against B. cereus and varied from sensitive to moderately sensitive for the non-B. cereus isolates. Our microbiologic laboratory findings suggest that vancomycin hydrochloride in combination with an aminoglycoside ensures more consistent antibiotic coverage of Bacillus species ocular infections.

Retained intraocular foreign bodies and endophthalmitis

Retained intraocular foreign bodies (IOFBs) are associated with endophthalmitis in approximately 7 to 13% of cases. The role of prompt surgical removal of the foreign body along with the use of intravitreal antibiotics in reducing this figure is uncertain. Retained IOFBs presenting to The Medical College of Wisconsin between July 1986 and June 1989 were reviewed. A total of 27 cases were evaluated and surgically treated. None of the 27 cases presented with or developed clinical signs of endophthalmitis, yet bacterial cultures of the removed intraocular material were positive in seven cases (foreign body in 5 cases, the aqueous fluid and the vitreous fluid in 1 case each). All eyes presenting within 24 hours of injury underwent immediate surgery (average, 4.5 hours after presentation). Of the seven eyes with positive intraocular cultures, all had pars plana vitrectomy removal of the IOFB and three of these eyes received intravitreal antibiotics at the time of surgery over concern of a high risk of infection. Two of these eyes eventually grew out the Bacillus sp. All eyes received subconjunctival antibiotics and postoperative topical and systemic antibiotics. Even after the positive cultures, no signs of clinical infection developed in any of the eyes. All seven eyes retained excellent visual acuity of 20/70 or better at an average of 10 months' follow-up. Follow-up ranged from 1 to 31 months. Prompt surgical intervention, the use of intravitreal antibiotics in high-risk-type injuries, and the possible use of vitrectomy surgery may reduce the incidence and severity of endophthalmitis.