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

Antimicrobial resistance in ocular infection: A review

Antimicrobial resistance (AMR) is a global public health threat with significant impact on treatment outcomes. The World Health Organization's Global Action Plan on AMR recommended strengthening the evidence base through surveillance programs and research. Comprehensive, timely data on AMR for organisms isolated from ocular infections are needed to guide treatment decisions and inform researchers and microbiologists of emerging trends. This article aims to provide an update on the development of AMR in ocular organisms, AMR in bacterial ocular infections and on AMR stewardship programs globally. The most common ocular pathogens are Pseudomonas aeruginosa, Staphylococcus spp., Streptococcus pneumoniae, and Haemophilus influenzae in ocular infections. A variety of studies and a few surveillance programs worldwide have reported on AMR in these infections over time. Fluoroquinolone resistance has increased particularly in Asia and North America. For conjunctivitis, the ARMOR cumulative study in the USA reported a slight decrease in resistance to ciprofloxacin. For keratitis, resistance to methicillin has remained stable for S. aureus and CoNS, while resistance to ciprofloxacin has decreased for MRSA globally. Methicillin-resistance and multidrug resistance are also emerging, requiring ongoing monitoring. Antimicrobial stewardship (AMS) programmes have a critical role in reducing the threat of AMR and improving treatment outcomes. To be successful AMS must be informed by up-to-date AMR surveillance data. As a profession it is timely for ophthalmology to act to prevent AMR leading to greater visual loss through supporting surveillance programmes and establishing AMS.

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.

Gallium-Based Nanoplatform for Combating Multidrug-Resistant Pseudomonas aeruginosa and Postoperative Inflammation in Endophthalmitis Secondary to Cataract Surgery

Postcataract endophthalmitis (PCE), a devastating complication following cataract surgeries, is one of the most crucial diseases causing irreversible eye blindness. Pseudomonas aeruginosa (PA), a multiple-drug-resistance (MDR) pathogen, always leads to uncontrolled infection and severe inflammation in PCE that can be difficult to treat by antibiotics. Therefore, it is urgent to develop new feasible strategies composed of both antibacterial and anti-inflammatory capabilities. Here, we report a multifunctional non-antibiotic nanoplatform (Ga-mSiO₂-BFN) comprised of clinically approved gallium, mesoporous silica, and bromfenac (BFN) as a co-modified release system to simultaneously eradicate MDR-PA infection and cure inflammation for PCE. The released gallium ions can disrupt bacterial iron metabolism. Meanwhile, the simultaneously released BFN can suppresses the inflammation both postoperation and postinfection of PCE. In the PCE rabbit model, the slit-lamp dispersion and retro-illumination micrograph, ophthalmic clinical grading, and etiological histopathology analysis demonstrated that Ga-mSiO₂-BFN could eradicate the MDR infection and alleviate the secondary inflammation from MDR-PA infection. Moreover, both cellular biocompatibility and in vivo animal model application verified the biocompatibility. A potential antibacterial mechanism implicated in the antibacterial action was demonstrated by comprehensive assays of iron antagonism evolutionary curve, colony autofluorescence, polymerase chain reaction, and electron microscopy, showing a repressing siderophore peptide pyoverdine, pyoverdine synthetase D, and interfering with bacterial DNA synthesis. All composites of our nanoplatform were FDA approved, making the Ga-mSiO₂-BFN as a potentially promising therapeutic approach for treating MDR-PA in PCE accompanying satisfactory prognosis and prospects for clinical translations.

Microbial Adherence to Contact Lenses and Pseudomonas aeruginosa as a Model Organism for Microbial Keratitis

Microbial keratitis (MK), the infection of the cornea, is a devastating disease and the fifth leading cause of blindness and visual impairment around the world. The overwhelming majority of MK cases are linked to contact lens wear combined with factors which promote infection such as corneal abrasion, an immunocompromised state, improper contact lens use, or failing to routinely disinfect lenses after wear. Contact lens-related MK involves the adherence of microorganisms to the contact lens. Therefore, this review discusses the information currently available regarding the disease pathophysiology, the common types of microorganisms causing MK, physical and organic mechanisms of adhesion, material properties which are involved in adhesion, and current antimicrobial strategies. This review also concludes that Pseudomonas aeruginosa is a model organism for the investigation of contact lens microbial adherence due to its prevalence in MK cases, its extremely robust adhesion, antimicrobial-resistant properties, and the severity of the disease it causes.

Surveillance of antimicrobial resistance in low- and middle-income countries: a scattered picture

Data on comprehensive population-based surveillance of antimicrobial resistance is lacking. In low- and middle-income countries, the challenges are high due to weak laboratory capacity, poor health systems governance, lack of health information systems, and limited resources. Developing countries struggle with political and social dilemma, and bear a high health and economic burden of communicable diseases. Available data are fragmented and lack representativeness which limits their use to advice health policy makers and orientate the efficient allocation of funding and financial resources on programs to mitigate resistance. Low-quality data means soaring rates of antimicrobial resistance and the inability to track and map the spread of resistance, detect early outbreaks, and set national health policy to tackle resistance. Here, we review the barriers and limitations of conducting effective antimicrobial resistance surveillance, and we highlight multiple incremental approaches that may offer opportunities to strengthen population-based surveillance if tailored to the context of each country.

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.

Multidrug-Resistant Pseudomonas aeruginosa Evokes Differential Inflammatory Responses in Human Microglial and Retinal Pigment Epithelial Cells

Increasing incidences of multidrug-resistant (MDR) pathogens causing endophthalmitis threaten our ability to treat this condition, and the modulation of inflammatory responses by MDR bacteria is not known. In this study, using human microglia and retinal pigment epithelial (RPE) cells, we compare the inflammatory responses of sensitive (S-PA) and multidrug-resistant (MDR-PA) clinical isolates of Pseudomonas aeruginosa. Infected cells were subjected to qPCR analysis, enzyme-linked immunosorbent assay (ELISA), and immunostaining to assess the expression of inflammatory mediators. Both microglia and RPE cells, challenged with S-PA and MDR-PA, induced a time-dependent expression of inflammatory cytokines. Significant differences were observed in expression levels of Toll-like receptors (TLR) TLR4, TLR5, and TLR9 in microglia cells challenged with MDR-PA vs. S-PA. Similarly, mRNA levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, Interferon (IFN)-γ, and matrix metalloproteinase (MMP)-9 were also higher in MDR-PA-infected cells. At protein levels, upregulation was observed for IL-10 (p = 0.004), IL-8 (p = 0.0006), IL-1β (p = 0.02), and Granulocyte-macrophage colony-stimulating factor (GM-CSF) (p = 0.0006) in cells infected MDR-PA versus S-PA in both microglia and RPE cells; however, the response was delayed in RPE cells. Heatmap and STRING analysis highlighted the existence of a cross-talk between the inflammatory and cytokine-mediated signaling pathways. Our study highlights a differential inflammatory response evoked by MDR vs. sensitive pathogens in retinal cells during endophthalmitis.