ENDOPHTHALMITIS CAUSED BY PROTEUS SPECIES: Antibiotic Sensitivities and Visual Acuity Outcomes

Endophthalmitis Due to Proteus vulgaris after Pars Plana Vitrectomy with Devastating Outcome

Postoperative infectious endophthalmitis is rare, yet devastating loss of vision or loss of the eye can occur due to a highly purulent microorganism or uncontrolled endophthalmitis that may spread to all coats of the eye. We report, herewith, a case of rapidly progressive postoperative endophthalmitis after pars plana vitrectomy which ended up with enucleation. The isolated microorganism was Proteus vulgaris which has not been reported as causative bacteria of postoperative infections following pars plana vitrectomy.

Composition and pathogenic potential of a microbial bioremediation product used for crude oil degradation

A microbial bioremediation product (MBP) used for large-scale oil degradation was investigated for microbial constituents and possible pathogenicity. Aerobic growth on various media yielded >108 colonies mL-1. Full-length 16S rDNA sequencing and fatty acid profiling from morphologically distinct colonies revealed ≥13 distinct genera. Full-length 16S rDNA library sequencing, by either Sanger or long-read PacBio technology, suggested that up to 21% of the MBP was composed of Arcobacter. Other high abundance microbial constituents (>6%) included the genera Proteus, Enterococcus, Dysgonomonas and several genera in the order Bacteroidales. The MBP was most susceptible to ciprofloxacin, doxycycline, gentamicin, and meropenam. MBP exposure of human HT29 and A549 cells caused significant cytotoxicity, and bacterial growth and adherence. An acellular MBP filtrate was also cytotoxic to HT29, but not A549. Both MBP and filtrate exposures elevated the neutrophil chemoattractant IL-8. In endotracheal murine exposures, bacterial pulmonary clearance was complete after one-week. Elevation of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α, and chemokines KC and MCP-1 occurred between 2h and 48h post-exposure, followed by restoration to baseline levels at 96h. Cytokine/chemokine signalling was accompanied by elevated blood neutrophils and monocytes at 4h and 48h, respectively. Peripheral acute phase response markers were maximal at 24h. All indicators examined returned to baseline values by 168h. In contrast to HT29, but similar to A549 observations, MBP filtrate did not induce significant murine effects with the indicators examined. The results demonstrated the potentially complex nature of MBPs and transient immunological effects during exposure. Products containing microbes should be scrutinized for pathogenic components and subjected to characterisation and quality validation prior to commercial release.

Clinical presentations, risk factors and outcomes of ceftazidime-resistant Gram-negative endophthalmitis

BACKGROUND

To describe the clinical features and outcomes of patients diagnosed with ceftazidime-resistant Gram-negative endophthalmitis and the role of intravitreal imipenem in these cases.

DESIGN

Retrospective consecutive interventional case series at a tertiary eye care centre in South India.

PARTICIPANTS

Consecutive cases of ceftazidime-resistant Gram-negative endophthalmitis from April 2010 to December 2014. Fifty-six cases diagnosed during this time period were included.

METHODS

All cases were managed with vitreous biopsy/vitrectomy, microscopy and undiluted vitreous culture, antimicrobial susceptibility of bacterial isolates and received intravitreal antibiotics.

MAIN OUTCOME MEASURES

Anatomic and visual outcome of these cases, antimicrobial susceptibility pattern of intravitreal imipenem and outcome of cases injected with it.

RESULTS

Commonest presentation was acute endophthalmitis following cataract surgery (27 eyes, 48.21%). Pseudomonas aeruginosa was isolated in 33 eyes (58.93%; 95% CI 46.05-71.81%). Nineteen eyes (34%; 95% CI 21.59-46.41%) developed phthisis; 14 eyes (25%; 95% CI 13.66-36.34%) had vision <20/200; 17 eyes (30.35%; 95% CI 18.31-42.39%) eyes had an ambulatory vision >20/200 (logMAR 1); 6 eyes (10.71%; 95% CI 2.61-18.81%) had a reading vision >20/40 (logMAR 0.3). Trend was towards better anatomic (72.73% vs. 40%) (P = 0.05) and visual improvement in the imipenem group (logMAR 3.94 + 0.21 to 2.43 + 1.4; P = 0.002), as compared with non-imipenem group (logMAR 2.99 + 1.3 to 2.55 + 1.4; P = 0.13).

CONCLUSIONS

Outcome of ceftazidime-resistant Gram-negative endophthalmitis is poor. P. aeruginosa is the commonest isolated organism. All cases were sensitive to imipenem. There was a trend towards better anatomic outcome in imipenem-treated eyes.

Proteus mirabilis and its role in dacryocystitis

PURPOSE

Dacryocystitis is a common inflammation of the lacrimal sac, usually from an underlying bacterial infection. Most cases can be attributed to common ocular flora such as Staphylococcus aureus or Streptococcus pneumoniae; however, uncommon bacterial causes such as Proteus mirabilis can still occur. P. mirabilis is a gram-negative bacillus that is found abundantly in people who have undergone long-term catheterization and is uncommonly found in or around the eyes except in people who have undergone long-term catheterization. Proteus species can cause conjunctivitis, canaliculitis, and dacryocystitis and have the ability to manifest into preseptal cellulitis; therefore, timely recognition and treatment are important to prevent potential further complications.

CASE REPORT

An 84-year-old white man had several recurrences of acute dacryocystitis that had marginal improvement with empiric antibiotic treatment. Resultant culture of the ocular discharge revealed an uncommon bacterium, P. mirabilis. Successful dosing of oral antibiotics resolved the infection but ultimately the patient required an external dacryocystorhinostomy (DCR) procedure to maintain patency of the nasolacrimal lacrimal system and prevent recurrence. At 3 months after external DCR, the patient was symptom free with no recurrences.

CONCLUSIONS

Dacryocystitis has a distinctive clinical presentation and is usually easily treated when appropriate oral antibiotics are directed at the underlying pathogen. In nonresponsive cases, culturing of the ocular discharge should be performed to identify the underlying pathogen. Cases of dacryocystitis caused by Proteus species are usually responsive to several standard antibiotics used orally in eye care; however, culturing and susceptibility testing can streamline the diagnostic and management sequence considerably in unclear or unresponsive cases. Typically, patients with dacryocystitis return to normal after appropriate treatment, but chronic recurrences and epiphora are potential sequelae. Patients should be educated that a DCR surgical procedure may be needed to prevent future recurrences in some cases.

Severe bacterial endophthalmitis: towards improving clinical outcomes

Endophthalmitis is an infection and inflammation of the interior of the eye that can result in significant vision loss. This infection occurs as a result of the seeding of organisms into the interior of the eye following surgery (postoperative), trauma (post-traumatic) or an infection in another site in the body (endogenous). The general rate of endophthalmitis has remained steady over the past several years. However, the increased use of intraocular injections to treat various degenerative and inflammatory ocular diseases, in addition to the already large and growing number of invasive ocular surgeries, may increase the opportunities in which organisms can gain access to the eye. In most cases of endophthalmitis, useful vision can be retained if proper treatment is instituted. However, in severe cases of bacterial endophthalmitis, blindness often occurs despite treatment. This article summarizes information on endophthalmitis epidemiology, treatment issues and current regimens, and recent experimental and clinical efforts to improve the outcome of severe and blinding forms of bacterial endophthalmitis.

Enterobacter endophthalmitis: clinicomicrobiologic profile and outcomes

PURPOSE

To report the clinical presentations, antibiotic sensitivities, management, and outcomes of Enterobacter endophthalmitis.

METHODS

This is a retrospective, consecutive, noncomparative, interventional case series. The medical records of culture-proven Enterobacter endophthalmitis cases from the endophthalmitis registry between January 1995 and March 2006 were reviewed.

RESULTS

Enterobacter was the causative agent in 36 culture-proven cases. The causative event was cataract surgery in 11 and trauma in 25 patients. The presenting visual acuity was light perception in 26 eyes (72.2%). Polymicrobial infection was detected in 7 patients (19.4%). Enterobacter organisms were most sensitive to ciprofloxacin (n = 34; 94%), followed by amikacin (n = 31; 86%) and ceftazidime (n = 28; 78%). In postoperative endophthalmitis, final visual outcome of ≥20/200 was achieved in 3 patients (27%) and of ≥5/200 in 5 patients (45%). The eyes became phthisical in 3 patients (27%) and evisceration was carried out in 1 patient. In posttraumatic endophthalmitis, final visual outcome of ≥20/200 was achieved in 5 patients (20%) and of ≥5/200 in 7 patients (28%). The eyes of 11 patients (44%) became phthisical and evisceration was carried out in 1 patient.

CONCLUSION

Enterobacter organisms are mostly susceptible to ciprofloxacin, amikacin, and ceftazidime. Despite this coverage, the visual outcome is often poor.

Antibiotic resistance in ocular bacterial pathogens

Bacterial infections of the eye are common and ophthalmologists are spoilt for choice with a variety of antibiotics available in the market. Antibiotics can be administered in the eye by a number of routes; topical, subconjunctival, subtenon and intraocular. Apart from a gamut of eye drops available, ophthalmologists also have the option of preparing fortified eye drops from parenteral formulations, thereby, achieving high concentrations; often much above the minimum inhibitory concentration (MIC), of antibiotics in ocular tissues during therapy. Antibiotic resistance among ocular pathogens is increasing in parallel with the increase seen over the years in bacteria associated with systemic infections. Although it is believed that the rise in resistant ocular bacterial isolates is linked to the rise in resistant systemic pathogens, recent evidence has correlated the emergence of resistant bacteria in the eye to prior topical antibiotic therapy. One would like to believe that either of these contributes to the emergence of resistance to antibiotics among ocular pathogens. Until recently, ocular pathogens resistant to fluoroquinolones have been minimal but the pattern is currently alarming. The new 8-fluoroquinolone on the scene-besifloxacin, is developed exclusively for ophthalmic use and it is hoped that it will escape the selective pressure for resistance because of lack of systemic use. In addition to development of new antibacterial agents, the strategies to halt or control further development of resistant ocular pathogens should always include judicious use of antibiotics in the treatment of human, animal or plant diseases.