ENDOPHTHALMITIS CAUSED BY PSEUDOMONAS AERUGINOSA: Clinical Features, Antibiotic Susceptibilities, and Treatment Outcomes

POSTINTRAVITREAL INJECTION AND POSTCATARACT EXTRACTION ENDOPHTHALMITIS VISUAL OUTCOMES BY ORGANISM: A SYSTEMATIC REVIEW AND META-ANALYSIS

PURPOSE

To compare visual outcomes of endophthalmitis following intravitreal injections (IVIs) and cataract extraction by causative organism.

METHODS

Searches in Cochrane Central Register of Controlled Trials, MEDLINE, and Embase identified articles reporting visual outcomes by causative organisms in post-IVI and cataract extraction endophthalmitis cases from January 2010 to February 2022. A random-effects meta-analysis compared visual improvement among endophthalmitis cases caused by causative organisms.

RESULTS

Eighty-five out of 3,317 retrieved studies were included. The highest degree of visual acuity improvement in both post-IVI and postcataract extraction endophthalmitis was seen in cases caused by coagulase-negative staphylococci, followed by gram-negative organisms and other gram-positive organisms such as streptococci and enterococci. Culture-negative cases showed more visual acuity improvement than culture-positive cases in post-IVI endophthalmitis. These results remained consistent when accounting for endophthalmitis treatment, IVI type, condition requiring IVI treatment, follow-up period, and initial preprocedural visual acuity.

CONCLUSION

Coagulase-negative staphylococci and gram-negative organisms show the most visual acuity improvement in both post-IVI and postcataract extraction endophthalmitis. Other gram-positive organisms such as streptococci and enterococci are associated with less visual improvement. This updated systematic review and meta-analysis revealed that the results of the Endophthalmitis Vitrectomy Study are consistent decades later despite advancements in surgical practices and the evolution of microorganisms over time.

Clinical settings, management and factors affecting outcomes in multi and extensively-drug resistant Pseudomonas endophthalmitis

PURPOSE

To report the clinical settings, management and factors affecting outcomes in multi-drug resistant (MDR) and extensively-drug resistant (XDR) Pseudomonas endophthalmitis.

SETTINGS

Retrospective, consecutive, non-comparative interventional case series. Cases of MDR and XDR Pseudomonas endophthalmitis from January 2012 to December 2020 treated at our tertiary eye care center were included. Data collected included clinical data, anatomic and functional outcome, isolated micro-organisms, and culture sensitivity.

RESULTS

This study included 29 eyes of 29 patients with MDR/XDR Pseudomonas endophthalmitis. Mean age at presentation was 60.27 ± 14.9 years (median 63). Commonest clinical setting was acute post-operative endophthalmitis in 27 cases (93.1%). Concurrent corneal infiltrate was present in 11 eyes (37.9%). Initial intervention in 19 eyes (65.5%) was vitrectomy, 2 of which underwent endoscopic pars plana vitrectomy. Mean number of interventions was 3.34 ± 1.44 (median 4). Mean follow up was 3.25 ± 3.07 months (median 2). Sensitivity to ceftazidime was 48.28%. All isolates were sensitive to colistin. Mean visual acuity at last follow up in logMAR was 2.64 ± 1.48 (median 3.5). Seven eyes (24.13%) were NPL (nil perception of light) at the last follow up. Two eyes (6.9%) underwent evisceration. Nine eyes (31.03%) had a favourable anatomic and functional outcome. Eyes without a corneal infiltrate at presentation were found to have a favourable anatomic and favourable functional outcome (OR 11.91, P < 0.04, CI 1.08 to 130.93).

CONCLUSION

Corneal involvement at presentation is associated with poorer outcomes in MDR and XDR Pseudomonas endophthalmitis. There is a potential role of higher newer antibiotics especially colistin in the management of these cases.

Ocular Bacterial Infections: A Ten-Year Survey and Review of Causative Organisms Based on the Oklahoma Experience

Ocular infections can be medical emergencies that result in permanent visual impairment or blindness and loss of quality of life. Bacteria are a major cause of ocular infections. Effective treatment of ocular infections requires knowledge of which bacteria are the likely cause of the infection. This survey of ocular bacterial isolates and review of ocular pathogens is based on a survey of a collection of isolates banked over a ten-year span at the Dean McGee Eye Institute in Oklahoma. These findings illustrate the diversity of bacteria isolated from the eye, ranging from common species to rare and unique species. At all sampled sites, staphylococci were the predominant bacteria isolated. Pseudomonads were the most common Gram-negative bacterial isolate, except in vitreous, where Serratia was the most common Gram-negative bacterial isolate. Here, we discuss the range of ocular infections that these species have been documented to cause and treatment options for these infections. Although a highly diverse spectrum of species has been isolated from the eye, the majority of infections are caused by Gram-positive species, and in most infections, empiric treatments are effective.

Gram-Negative Endogenous Endophthalmitis: A Systematic Review

Background: Gram-negative bacteria are causative agents of endogenous endophthalmitis (EBE). We aim to systematically review the current literature to assess the aetiologies, risk factors, and early ocular lesions in cases of Gram-negative EBE. Methods: All peer-reviewed articles between January 2002 and August 2022 regarding Gram-negative EBE were included. We conducted a literature search on PubMed and Cochrane Controlled Trials. Results: A total of 115 studies and 591 patients were included, prevalently Asian (98; 81.7%) and male (302; 62.9%). The most common comorbidity was diabetes (231; 55%). The main aetiologies were Klebsiella pneumoniae (510; 66.1%), Pseudomonas aeruginosa (111; 14.4%), and Escherichia coli (60; 7.8%). Liver abscesses (266; 54.5%) were the predominant source of infection. The most frequent ocular lesions were vitreal opacity (134; 49.6%) and hypopyon (95; 35.2%). Ceftriaxone (76; 30.9%), fluoroquinolones (14; 14.4%), and ceftazidime (213; 78.0%) were the most widely used as systemic, topical, and intravitreal anti-Gram-negative agents, respectively. The most reported surgical approaches were vitrectomy (130; 24.1%) and evisceration/exenteration (60; 11.1%). Frequently, visual acuity at discharge was no light perception (301; 55.2%). Conclusions: Gram-negative EBEs are associated with poor outcomes. Our systematic review is mainly based on case reports and case series with significant heterogeneity. The main strength is the large sample spanning over 20 years. Our findings underscore the importance of considering ocular involvement in Gram-negative infections.

Temporal Transcriptome Analysis Suggests Modulation of Key Pathways and Hub Genes in a Mice Model of Multi-Drug Resistant (MDR) Pseudomonas aeruginosa Endophthalmitis

PURPOSE

Increasing incidence of multidrug-resistant Pseudomonas aeruginosa (MDR-PA) causing endophthalmitis challenges our ability to manage this vision-threatening condition. In this study, temporal dynamics of immune response in a mouse model of MDR-PA endophthalmitis was investigated by whole transcriptome analysis.

METHODS

C57BL/6 mice were infected with MDR-PA and antibiotic susceptible (S-PA) clinical strains and disease severity were monitored at 6 and 24-h postinfection (p.i), following which eyeballs were enucleated. Microarray analysis was performed using SuperPrint G3 Mouse Gene Expression v2 chip and the differential gene expression analysis was performed with limma package in R (v4.0.0.)/Bioconductor (v3.11).

RESULTS

Histopathological analysis revealed a significant difference in retinal architecture and vitreous infiltrates at 6 and 24 h. In comparison to S-PA, MDR-PA revealed altered expression of 923 genes at 6 h and 2220 genes at 24 h. Further, 23 and 76% of these altered genes and its downstream interacting proteins showed time-specific expression (6 and 24 h respectively), indicating their association with disease progression. At 24 hours, MDR-PA induced endophthalmitis showed aberrant immune response with the enrichment inflammasome signalling, dysregulated ubiquitination, complement cascade, MMPs NF-κβ and IL-1 signalling.

CONCLUSION

The rapid development of transcriptional differences between the two-time points reveals that distinct genes contribute to disease severity. The results from this study highlighted a link between innate and adaptive immune responses and provided novel insights in the pathogenesis of MDR-PA endophthalmitis by extending the number of molecular determinants and functional pathways that underpin host-associated damage.

Endophthalmitis Caused by Pseudomonas aeruginosa: Clinical Characteristics, Outcomes, and Antibiotics Sensitivities

Purpose

The aim of this study is to report the clinical characteristics, visual outcomes, and antibiotic susceptibilities of patients with Pseudomonas aeruginosa endophthalmitis.

Methods

The medical records of patients with culture-proven Pseudomonas aeruginosa endophthalmitis treated from June 2013 to December 2019 were reviewed.

Results

This study included 36 eyes of 36 patients. The clinical settings included ocular trauma (15/36), corneal ulcer (9/36), postoperative endophthalmitis (5/36), endogenous (3/36), and unknown (4/36). Sixteen patients underwent evisceration, 13 patients underwent pars plana vitrectomy (PPV), 2 patients were treated with only intravitreal antibiotics, and 5 patients did not undergo surgery. Only one patient achieved a visual acuity of 20/400, and the others had all counting fingers or below. The cultured Pseudomonas aeruginosa was 100% sensitive to gentamicin, tobramycin, amikacin, ciprofloxacin, and levofloxacin and, approximately 95% sensitive to meropenem, imipenem, and aztreonam.

Conclusion

The visual outcomes of Pseudomonas aeruginosa endophthalmitis were very poor, and the evisceration rate remained high. Pseudomonas aeruginosa has good susceptibility to gentamicin, tobramycin, amikacin, ciprofloxacin, and levofloxacin.

The microbiological spectrum, antimicrobial resistance pattern, and visual outcomes of endogenous endophthalmitis in West Virginia 2009-2019

PURPOSE

To report the microbiological spectrum, antimicrobial resistance patterns, and visual outcomes in patients with endogenous endophthalmitis (EE).

METHODS

This was a retrospective study of 50 patients with culture-positive EE managed in a tertiary referral center between October 2009 and 2019. Clinical, microbiology analysis, and antimicrobial resistance were reviewed. A multivariable linear regression analysis was used for identifying risk factors associated with worse visual outcomes.

RESULTS

Fifty organisms were identified, 62% bacterial and 38% fungal. The most common bacterial organism was Staphylococcus aureus (75% methicillin resistant), and Candida was the most common fungal species. Multidrug resistance was observed in methicillin-resistant Staphylococcus aureus (MRSA) isolates against clindamycin, daptomycin, and fluoroquinolones. The distributions of the final visual acuity (VA) between the bacterial and fungal groups were significantly different, and the visual outcomes in the bacterial group tended to be worse (p = 0.01). The distributions of enucleation status were significantly higher in bacterial EE (35%) than fungal EE (5.3%) (p = 0.02). Results from the multivariable linear regression analysis revealed that older age was significantly associated with worse visual outcome (coef = 0.03; p = 0.02), while fungal infections were associated with better outcomes (coef = - 0.87; p = 0.01). Intravenous drug use (coef = 0.87; p = 0.054) was a marginally significant factor associated with worse visual outcomes.

CONCLUSION

There was a higher prevalence of bacterial organisms than fungal species among EE. Bacterial EE was associated with worse visual outcomes and higher enucleation rates than fungal EE. Multidrug resistance was prevalent among MRSA isolates. Older age and intravenous drug use may be factors associated with poor prognosis.

Emerging antimicrobial resistance and need for antimicrobial stewardship for ocular infections in India: A narrative review

Patients with ocular infections are at increased risk of vision impairment and may require immediate medical care to preserve their vision. Management of ocular bacterial infections has evolved in recent years and includes a pragmatic selection of broad-spectrum antibiotics based on the causative bacteria. Nevertheless, the treatment of bacterial ocular infections is increasingly becoming a challenge, as the causative bacterium acquires resistance to antibiotics through intrinsic and acquired methods. From an Indian perspective, along with the challenges of antibiotic resistance, there are other factors such as lack of knowledge on epidemiology, and lack of data on local susceptibility patterns of ocular pathogens that have significant impact on the management of ocular infections. This narrative review summarizes the available knowledge on prescribing antibiotics for five common ocular infections in India. It further highlights the significance of the understanding of antimicrobial susceptibility patterns across India as a cornerstone to promote rational use of ocular antibiotics. This review indicates that large-scale antimicrobial resistance surveillance studies can facilitate the synchronization of ophthalmic antimicrobial prescription policies with local antibiotic resistance patterns. Further, establishment of an antimicrobial stewardship program in ophthalmology can potentially increase the efficacy of diagnostic tools, and implement earlier adoption of effective antibiotics. Overall, this review provides consolidated information and key considerations for treatment decision-making of common ocular infections in India.

Postoperative Pseudomonas aeruginosa endophthalmitis associated with asymptomatic bacteriuria

An 86-year-old man with diabetes and a history of prostate cancer, indwelling urinary catheter and Pseudomonas aeruginosa bacteriuria presented on day 4 post left phacoemulsification cataract extraction and intraocular lens implant with signs and symptoms of postoperative endophthalmitis. Vitreous sample was positive for P. aeruginosa Prompt treatment with intravitreal antibiotics was initiated followed by anterior chamber washout with pars plana vitrectomy; however, the visual outcome was poor.

Transcriptomic and Histological Analysis of Exacerbated Immune Response in Multidrug-Resistant Pseudomonas aeruginosa in a Murine Model of Endophthalmitis

Multidrug-resistant (MDR) endophthalmitis is a serious threat to the whole spectrum of therapeutic procedures associated with the risk of managing and preventing vision loss. We have earlier shown the interplay of immune mediators in patients with MDR Pseudomonas aeruginosa (PA) endophthalmitis leading to worse outcome. Expanding on these findings, a murine model of endophthalmitis was developed to explore the effects of drug resistance on the pathogenesis by analyzing the temporal changes in retinal morphology along with its transcriptomic signatures. Clinical isolates of susceptible (S-PA) and multidrug-resistant PA (MDR-PA) were injected intravitreally in C57BL/6 mice followed by enucleation at 6 and 24 h time points postinfection. Disease progression and retinal changes were monitored by clinical and histological assessment and transcriptome analysis in a pair-wise manner. Histological assessment of MDR-PA eyeball revealed higher disease severity (p < 0.05), CD45+ cells (p = 0.007), MPO+ cells (p = 0.01), GFAP+ (p = 0.02), along with higher retinal cell death in mice infected with MDR-PA (p = 0.008). Temporal transcriptome analysis revealed differential expression of nearly 923 genes at 6 h p.i. and 2,220 genes at 24 h p.i. (FC ≥2, adjusted p-value <0.05). Pathway enrichment analysis identified differential regulation of chemokine- and cytokine-mediated, MAPK, and NF-кβ signaling pathways. In conclusion, rapid deterioration of retinal architecture and immune exacerbation was significantly associated with the MDR endophthalmitis, suggesting the need for immunomodulatory agents to strengthen host cell functions and support antibiotics to save the retinal structure from inevitable deterioration and restoration of the vision.

In vitro study examining the effectiveness of antiseptic prophylaxis for antibiotic-resistant bacterial endophthalmitis

PURPOSE

To assess the effectiveness of current antiseptic agents on multidrug-resistant (MDR) isolates in an in vitro setting.

SETTING

Department of Microbiology, The National Maternity Hospital, Dublin, Ireland.

DESIGN

Organisms were selected based on current review of endophthalmitis literature: methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), Pseudomonas aeruginosa, carbapenem-resistant and extended-spectrum β-lactamase Klebsiella pneumoniae, and vancomycin-resistant (VRE) Enterococcus faecalis.

METHODS

Samples were exposed to povidone-iodine (PVI) 5% and chlorhexidine (CHX) 0.05% for 0.5 minutes, 1 minute, 3 minutes, and 5 minutes. After inactivation, organisms were incubated under standard conditions and growth assessed after 16 hours.

RESULTS

MRSA and MRSE responded to 3-minute PVI exposure. CHX eradicated MRSA growth after 5 minutes but failed to completely suppress MRSE. Pseudomonas and Klebsiella required 3-minute CHX exposure and 5-minute PVI exposure for complete clearance. Eradication of enterococci (VRE positive and negative) was not achieved at 10 minutes of CHX or PVI exposure. Comparison of PVI vs CHX showed a benefit for PVI in MRSA (P < .01) and MRSE (P < .001) eradication at 3 minutes.

CONCLUSIONS

Current recommendations of 3 minutes of antisepsis prior to intraocular surgery are not sufficient for complete eradication of MDR organisms from the ocular surface. A bespoke approach is suggested to patients at risk for carriage of MDR organisms to minimize the risk of endophthalmitis.

Antibiotic sensitivity trends of pseudomonas endophthalmitis in a tertiary eye care center in South India: A 12-year retrospective study

Purpose:

To assess trends in antibiotic sensitivity of pseudomonas and compare multidrug resistance (MDR) between Pseudomonas endophthalmitis cases presenting in two consecutive 6-year time frames in a tertiary center in South India.

Methods:

This is a retrospective comparative series of all Pseudomonas endophthalmitis cases treated from June 2004 to May 2016. Microbiological culture results in all endophthalmitis patients were screened for pseudomonas. Positive cases in the initial 6 and final 6 years were compared for sensitivity to antibiotics and the proportion of MDR. MDR was defined as resistance to at least two different classes of antibiotics.

Results:

Pseudomonas accounted for 74 of 389 endophthalmitis cases (19%), 42 in initial 6 and 32 in final 6 years. Sensitivity to ciprofloxacin, ofloxacin, gatifloxacin, moxifloxacin, and ceftazidime was 85.7%, 82.9%, 76.5%, 76.9%, 88.1% up to 2010 which reduced to 75%, 59.4%, 68.8%, 56.3%, 56.3%, respectively, after 2010, being significant for ofloxacin (P = 0.0349) and ceftazidime (P = 0.0028). Susceptibility to amikacin, gentamicin, and tobramycin changed non-significantly from 83.3%, 43.9%, 47.6% to 71.9%, 61.3%, 61.3%, respectively. Twenty of 74 cases (27%) were MDR with 16.7% in first 6 years versus 40.6% in final 6 years. Postoperative MDR cases rose from 10.3% to 50% (P = 0.0048).

Conclusion:

This study shows rising resistance of Pseudomonas to fluoroquinolones, amikacin, and ceftazidime in endophthalmitis. MDR also showed an upward trend, particularly in postsurgical cases.

Management of endophthalmitis related to glaucoma drainage devices: review of the literature and our experience

Glaucoma drainage device (GDD)-related endophthalmitis is a devastating complication of device implantation. There are no guidelines in the literature to assist clinicians in deciding if the GDD should be explanted or if patients require pars plana vitrectomy (PPV). This study compares the outcomes of GDD explantation with device retention and also independently compares the outcomes of PPV versus intravitreal antibiotics alone in patients with GDD-related endophthalmitis. A literature search for studies discussing GDD-related endophthalmitis from 2005 to 2019 was performed; 30 articles were included. The visual acuity/anatomical outcomes were compared between GDD explantation and retention, and between patients that received a PPV and those that did not. These outcomes were combined with a medical records review of 13 patients with GDD-related endophthalmitis from an academic institution. A total of 88 eyes were included. 70.5% underwent GDD explantation, while 37.8% received a PPV. GDD explantation was associated with a lower rate of evisceration/enucleation when compared to GDD retention (4.8% versus 19.2%, OR 0.22, 95% CI 0.05-1.01, p = 0.05), but visual acuity outcomes were similar. No eyes that received an immediate vitrectomy became phthisic or required evisceration/enucleation, compared an evisceration/enucleation rate of 15.2% in eyes treated solely with intravitreal antibiotics (OR 1.18, 95% CI 1.04-1.33, p = 0.04). Explantation of the GDD and immediate vitrectomy are both associated with better anatomical outcomes in GDD-related endophthalmitis. Further research is needed to provide more definitive guidelines in the ideal management of these patients.

Ten-year trends in the incidence, clinical profile and outcomes of acute-onset endophthalmitis following combined pars plana vitrectomy and sutureless, glueless and flapless scleral fixation of intraocular lenses

PURPOSE

To evaluate the frequency and outcomes of acute-onset endophthalmitis following combined pars plana vitrectomy and scleral fixation of intraocular lens.

METHODS

We evaluated patients undergoing a sutureless, glueless, flapless technique of scleral fixation of intraocular lenses (SFIOL) implantation for various causes of aphakia and documented the clinico-demographic data, microbiological profile and final outcome after acute endophthalmitis in this cohort of eyes.

RESULTS

The frequency of suspected acute endophthalmitis diagnosed post-surgery was 0.112% (4/3541 eyes), with culture-positive endophthalmitis frequency being 0.028% (1 eye), showing growth of Pseudomonas aeruginosa. Mean age of patients with endophthalmitis was 51.75 ± 9.28 years, and mean interval between surgery and acute endophthalmitis presentation was 10.25 ± 9.6 days. Patients were managed with intravitreal antibiotics with or without core vitrectomy. Visual acuity of patients increased from baseline 1.43 ± 0.32 logMAR (Snellen equivalent = 6/150) to 0.79 ± 0.16 logMAR (Snellen equivalent = 6/36) after an average follow-up of 11 ± 2 weeks.

CONCLUSION

Endophthalmitis is a rare complication following SFIOL surgery, and all ophthalmic surgeons must be aware of this inadvertent possibility, since SFIOLs are gaining wider acceptability recently. Moreover, these cases of endophthalmitis may show a different pattern of microorganisms than post-cataract surgery endophthalmitis; however, with prompt diagnosis and effective timely management, favorable outcomes can be achieved.

Characterization of Pseudomonas aeruginosa isolates from patients with endophthalmitis using conventional microbiologic techniques and whole genome sequencing

Purpose

To demonstrate antibiotic susceptibility and genomic virulence factor profiles of Pseudomonas aeruginosa isolates from patients with culture-confirmed endophthalmitis.

Methods

Clinical isolates from patients diagnosed with pseudomonas endophthalmitis were included. Laboratory antibiotic susceptibility testing and whole genome sequencing was performed on all isolates.

Results

In the current study, 8 patients had vitreous culture-confirmed endophthalmitis due to P. aeruginosa. All isolates were multi-drug resistant but sensitive to ceftazidime and each fluoroquinolone tested. Whole genome sequencing revealed a total of 179 unique genes. The most common type of virulence genes included those involved in adherence and the secretion system. Seven of 8 (88%) isolates were of the cytoinvasive phenotype (exoST) and no isolates contained exoU.

Conclusions

P. aeruginosa associated endophthalmitis is often multi-drug resistant and demonstrates a variety of virulence factors with those involved in adherence and the secretion system being the most common.

The Role of Systemic Antimicrobials in the Treatment of Endophthalmitis: A Review and an International Perspective

Background

The optimal management of patients with endophthalmitis is challenging and includes both intravitreal and, in some cases, systemic antimicrobials. Systemic antimicrobials may be administered either intravenously or orally. In this article we review systemic antimicrobial options currently available for the treatment of types of endophthalmitis and the role of systemic antimicrobials (antibiotics and antifungals) in these treatments.

Review

While systemic antimicrobials are not universally utilized in the management of endophthalmitis, they may be helpful in some circumstances. The blood–retinal barrier affects the penetration of systemic medications into the posterior segment of the eye differently; for example, moxifloxacin and imipenem cross the blood–retinal barrier relatively easily while vancomycin and amikacin do not. However, inflammation, including endophthalmitis, may disrupt the blood–retinal barrier, enhancing the penetration of systemic agents into the eye.

Conclusion

Systemic antimicrobials may be particularly beneficial in patients with certain types of endophthalmitis; as such, they are standard treatment in the management of endogenous endophthalmitis (fungal and bacterial) and also widely used for prophylaxis and treatment of open-globe injuries. Although systemic antimicrobials are used in some patients with acute-onset postoperative endophthalmitis following cataract surgery, the literature generally does not support this practice. It is noted that there are currently no randomized clinical trials demonstrating a benefit of systemic antibiotics for any category of endophthalmitis.

Antibiotics and antifungals in silicone oil

Background

Antimicrobials may be injected into silicone oil-filled eyes with endophthalmitis, but the interaction with oil is unclear. The purpose of the experiment is to determine whether vancomycin, amikacin, and amphotericin B mix with silicone oil.

Methods

Using the relative proportions of the human eye, 4 ml of 1000 centistokes silicone oil was centrifuged with 0.1 ml of vancomycin 1 mg/0.1 ml, amikacin 0.4 mg/0.1 ml, or amphotericin B 5 µg/0.1 ml in vitro and eluted. The aqueous was immediately analyzed with a liquid chromatographer/mass spectrometer and after 24 h.

Results

Within 24 h, a mean of 26.9 μmol/L of vancomycin, 0 nmol/L of amikacin, and 0 nmol/L of amphotericin B were recovered. When the concentrations of amikacin and amphotericin B were increased 100-fold, 0 nmol/L of amikacin and 75.7 µmol/L of amphotericin B were recovered.

Conclusions

Vancomycin and amphotericin B partially mixed with the silicone oil. Amikacin was not recovered from the antibiotic–silicone oil mixture.

Infectious endophthalmitis leading to evisceration: spectrum of bacterial and fungal pathogens and antibacterial susceptibility profile

Purpose

To describe the spectrum of bacterial and fungal pathogens in cases of endophthalmitis requiring evisceration and report their antimicrobial susceptibilities.

Methods

Retrospective, consecutive, and descriptive case series of endophthalmitis that underwent evisceration from January 2004 to December 2017. Vitreous samples from all patients had been investigated for bacteria and fungus using institutional protocol. Bacterial isolates were identified using analytical profile index (API) system until 2010 and Vitek-2 compact system (bioMérieux, France), thereafter. The susceptibility of bacterial isolates to a variety of antibiotics was determined by the Kirby-Bauer disk-diffusion method.

Results

Of 791 cases reviewed, culture positivity was reported in 388 cases (48.92%). Commonest clinical setting of endophthalmitis necessitating evisceration was post-microbial keratitis (58%), followed by post-trauma and post-cataract surgery (14–15%). The commonest isolate was Streptococcus pneumoniae, seen in 68 samples overall (17.52%). One hundred and eighty-three isolates (47.16%) were gram-positive, 86 (22.16%) were gram-negative, and fungi constituted 137 (35.3%) isolates. Streptococcus pneumoniae was the commonest gram-positive bacterial isolate seen in 68/183 samples (37.15%). Among gram-negative organisms, the commonest was Pseudomonas aeruginosa seen in 47/86 (54.65%). Aspergillus spp. formed the commonest fungal isolate, 58/137 (42.33%). The susceptibility of the gram-positive bacteria was highest with vancomycin, 136/147 (92.51%) and for gram-negative bacteria was seen best with imipenem 24/29 (82.75%). Susceptibility to ceftazidime was 31/61 (50.81%) in 31/61.

Conclusion

Endophthalmitis due to Pneumococci, Aspergillus, and Pseudomonas can be very fulminant and progress to require evisceration in spite of prompt and appropriate treatment.

Bactericidal and immunomodulatory properties of magnetic nanoparticles functionalized by 1,4-dihydropyridines

Background

1,4-Dihydropyridine (1,4-DHP) and its derivatives are well-known calcium channel blockers with antiarrhythmic and antihypertensive activities. These compounds exhibit pleiotropic effects including antimicrobial activities that rely on their positive charge and amphipathic nature. Use of magnetic nanoparticles (MNPs) as carriers of 1,4-DHP modulates their properties and enables improved formulations with higher efficacy and less toxicity.

Methods

In this study, the antimicrobial and immunomodulatory activities of novel 1,4-DHP derivatives in free form and immobilized on MNPs were determined by evaluating pathogen outgrowth and proinflammatory cytokine release in experimental settings that involve incubation of various 1,4-DHPs with clinical isolates of bacteria or fungi as well as mammalian cell culture models.

Results

Conventional immobilization of 1,4-DHP on aminosilane-coated MNPs markedly enhances their antimicrobial activity compared to nonimmobilized molecules, in part because of the higher affinity of these nanosystems for bacterial cell wall components in the presence of human body fluids.

Conclusion

Optimized nanosystems are characterized by improved biocompatibility and higher anti-inflammatory properties that provide new opportunities for the therapy of infectious diseases.

Bacterial and Fungal Endophthalmitis

Endophthalmitis is a severe eye infection that may result in permanent loss of useful vision in the affected eye. Most cases are exogenous and occur as a complication of cataract surgery, an intravitreal injection, or penetrating ocular trauma. Endogenous endophthalmitis results from hematogenous seeding of the eye by bacteria or fungi, but bacteremia or fungemia may be transient and patients may present without symptoms of systemic infection. Nearly all endophthalmitis patients present with decreased vision, and some also have eye pain. Eye examination usually reveals a hypopyon and intraocular inflammation. Diagnosis is clinical, supported by cultures of the vitreous and/or aqueous or by blood cultures in some endogenous cases. Molecular diagnostic techniques have been used in research laboratories for pathogen identification in endophthalmitis and offer the possibility of rapid diagnosis, including in culture-negative cases. Intravitreal injection of antibiotics is the most important component of treatment; some cases also benefit from surgical debridement of the vitreous by a vitrectomy. The visual outcome depends partly on the pathogen: coagulase-negative staphylococcal endophthalmitis has a better prognosis than does streptococcal endophthalmitis, for example. Endophthalmitis is a medical emergency, and prompt diagnosis and treatment are essential for saving vision.

Acute endophthalmitis after cataract surgery: 164 consecutive cases treated at a referral center in South Korea

PurposeTo identify prognostic factors in patients referred with endophthalmitis after cataract surgery, and to evaluate the efficacy of primary vitrectomy as an initial management.MethodsOver an eight-year study period, we retrospectively reviewed the medical records of 164 patients who were referred with endophthalmitis following cataract surgery. Treatment generally conformed to standard guidelines, although primary vitrectomy was performed in several eyes with a visual acuity of hand motion or better, depending on the patient's status. Using multivariate analysis, we analyzed outcomes to determine the effect on final visual outcome.ResultsA final visual acuity of ≥20/40 was achieved in 92/164 (56.1%) cases after treatment. Bacterial cultures showed bacterial growth in 89/164 cases (54.3%). Among the various baseline characteristics, old age (P=0.028), poor visual acuity at presentation (P=0.004), gram-negative bacterial infection (P=0.030), and short time between cataract surgery and signs of endophthalmitis (P=0.021) were associated with poor visual outcome. The visual outcome showed no significant difference, in terms of initial treatment feature, between the primary vitrectomy with intraocular antibiotics injection (IOAI) and IOAI-only groups. However, reintervention was significantly less frequent in the primary vitrectomy group than in the IOAI group (12.5 and 32.7%, respectively; P=0.002).ConclusionOld age, poor visual acuity at presentation, type of cultured organism (gram-negative bacteria), and early onset of endophthalmitis after cataract surgery were significantly related to poor visual outcome after endophthalmitis treatment. Primary vitrectomy may decrease the need for reintervention to control infection, although the treatment showed no benefits with regard to visual outcome.

Endophthalmitis Caused by Corynebacterium Species: Clinical Features, Antibiotic Susceptibility, and Treatment Outcomes

PURPOSE

To report the clinical features, antibiotic susceptibility profiles, treatment, and visual acuity (VA) outcomes of endophthalmitis caused by Corynebacterium species.

DESIGN

Retrospective case series.

SUBJECTS

Patients with endophthalmitis caused by Corynebacterium species.

METHODS

Microbiology database records were retrospectively reviewed for all patients with endophthalmitis caused by Corynebacterium species from January 1, 1990 to December 31, 2012 at a large university referral center. The corresponding clinical records were then reviewed to evaluate the endophthalmitis clinical features and treatment outcomes.

MAIN OUTCOME MEASURES

presenting clinical features, visual acuity outcomes, and antibiotic susceptibility patterns.

RESULTS

Of 10 patients identified, clinical settings included post-cataract surgery (n = 6), post-penetrating keratoplasty (n = 2), and post-trabeculectomy (n = 2). The mean time from surgical procedure to presentation with endophthalmitis was 6.8 months (range: 1 day to 28 months). All isolates were vancomycin susceptible. Presenting VA ranged from 7/200 to no light perception. Initial treatment strategies were vitreous tap and intravitreal antibiotic injection (n = 5) and pars plana vitrectomy with intravitreal antibiotic injection (n = 5). VA outcomes were ≥ 20/60 in 5 (50%) of 10 patients and ≤ 20/400 in 5 (50%) of 10 patients.

CONCLUSIONS

The most common clinical setting was post-cataract surgery. All isolates were susceptible to vancomycin. Despite prompt treatment with appropriate antibiotics, there were variable visual outcomes.