Corneal Infection Research Articles

Unveiling challenging corneal infections: a comprehensive etiological diagnosis through metagenomic next-generation sequencing (mNGS) of corneal tissue samples.

The objective of this study was to assess the clinical diagnostic value of metagenomic next-generation sequencing (mNGS) in cases of challenging corneal infections using corneal tissue samples. This retrospective study involved 42 patients with corneal infections, where conventional diagnostic techniques failed to identify the causative pathogen. Corneal tissue specimens underwent mNGS, followed by microbial culture for validation. Sensitivity-guided antimicrobial therapy was administered upon identification of the pathogen. The diagnostic and therapeutic efficacy of mNGS was analyzed to evaluate its clinical utility. A total of 42 patients were included in this study, with mNGS detection results obtained for 38 cases (90.48%). Among them, 30 cases (71.43%) were clinically significant, eight cases (19.05%) had low clinical relevance, and four cases (9.52%) showed no detection. Following corresponding antimicrobial treatment, 30 patients exhibited significant improvement, resulting in a treatment effectiveness of 71.43%. The prognosis of mNGS-positive patients was superior to that of mNGS-negative patients, with statistically significant differences observed (P < 0.001). Corneal tissue mNGS facilitated the rapid identification of causative agents in challenging corneal infections with unclear clinical diagnoses. It could be seamlessly integrated with traditional diagnostic methods to guide the diagnosis and treatment of corneal diseases.

Extracellular vesicles released by host epithelial cells during Pseudomonas aeruginosa infection function as homing beacons for neutrophils

BackgroundPseudomonas aeruginosa (PA) is an opportunistic pathogen that can cause sight threatening infections in the eye and fatal infections in the cystic fibrosis airway. Extracellular vesicles (EVs) are released by host cells during infection and by the bacteria themselves; however, there are no studies on the composition and functional role of host-derived EVs during PA infection of the eye or lung. Here we investigated the composition and capacity of EVs released by PA infected epithelial cells to modulate innate immune responses in host cells.MethodsHuman telomerase immortalized corneal epithelial cells (hTCEpi) cells and human telomerase immortalized bronchial epithelial cells (HBECs) were treated with a standard invasive test strain of Pseudomonas aeruginosa, PAO1, for 6 h. Host derived EVs were isolated by qEV size exclusion chromatography. EV proteomic profiles during infection were compared using mass spectrometry and functional studies were carried out using hTCEpi cells, HBECs, differentiated neutrophil-like HL-60 cells, and primary human neutrophils isolated from peripheral blood.ResultsEVs released from PA infected corneal epithelial cells increased pro-inflammatory cytokine production in naïve corneal epithelial cells and induced neutrophil chemotaxis independent of cytokine production. The EVs released from PA infected bronchial epithelial cells were also chemotactic although they failed to induce cytokine secretion from naïve HBECs. At the proteomic level, EVs derived from PA infected corneal epithelial cells exhibited lower complexity compared to bronchial epithelial cells, with the latter having reduced protein expression compared to the non-infected control.ConclusionsThis is the first study to comprehensively profile EVs released by corneal and bronchial epithelial cells during Pseudomonas infection. Together, these findings show that EVs released by PA infected corneal and bronchial epithelial cells function as potent mediators of neutrophil migration, contributing to the exuberant neutrophil response that occurs during infection in these tissues.

The incidence of severe complications in acanthamoeba keratitis: Qualitative and quantitative systematic assessment

Acanthamoeba keratitis (AK) is a rare, sight-threating corneal infection. The disease is challenging to diagnose and treat, and the amoeba can rapidly encyst, persisting in the tissue and causing recurrences. Medical therapy is conventionally considered the first line treatment, but advanced cases could require more invasive treatments like a “chaud” corneal transplant. We review the incidence of severe complications in patients affected by AK. Of 439 reports screened, 158 met our inclusion criteria. Incidence of severe complications was low, with 2.21 % patients developing perforation, 1 % requiring evisceration/enucleation and less than 1 % developing endophthalmitis. Corneal transplantation was required in 16.68 % of the cases. According to our results, and considering the reported incidences of these complications in other infectious keratitis, AK patients have an overall low risk of developing perforation, endophthalmitis, and enucleation/evisceration. Nevertheless, data available in the literature remain poor, and further randomized control trials are needed to confirm our findings.

No Evidence of Chronic Infection in a Metagenomic Sequencing Study of the Keratoconus Corneal Epithelium.

Objectives: This study aims to assess the presence of pathogenic microorganisms in the corneal epithelial layer of keratoconus patients. Methods: DNA was extracted from corneal epithelial samples procured from ten individual keratoconus eyes and three healthy controls. Metagenomic next-generation sequencing (mNGS) was performed to detect ocular microbiota using an agnostic approach. Results: Metagenomic sequencing revealed a low microbial read count in corneal epithelial samples derived from both keratoconus eyes (average: 530) and controls (average: 622) without a statistically significant difference (p = 0.29). Proteobacteria were the predominant phylum in both keratoconus and control samples (relative abundance: 72% versus 79%, respectively). Conclusions: The overall low microbial read count and the lack of difference in the relative abundance of different microbial species between keratoconus and control samples do not support the hypothesis that a chronic corneal infection is implicated in the pathogenesis of keratoconus. These findings do not rule out the possibility that an acute infection may be involved in the disease process as an initiating event.

Involvement of cGAS/STING Signaling in the Pathogenesis of Candida albicans Keratitis: Insights From Genetic and Pharmacological Approaches.

Fungal keratitis (FK) is an invasive corneal infection associated with significant risk to vision. Although the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) signaling pathway has been recognized for its role in defending against viral infections, its involvement in FK still remains largely unclear. This study sought to elucidate the contribution of the cGAS/STING signaling pathway to the pathogenesis of FK. The expression of cGAS/STING signaling components was assessed in a murine model of Candida albicans keratitis through RNA sequencing, western blot analysis, immunofluorescence staining, and real-time PCR. Both genetic (utilizing Sting1gt/gt mice) and pharmacological (using C176) interventions were employed to inhibit STING activity, allowing for the evaluation of resultant pathogenic alterations in FK using slit-lamp examination, clinical scoring, hematoxylin and eosin (H&E) staining, fungal culture, and RNA sequencing. Subconjunctival administration of the NOD-like receptor protein 3 (NLRP3) inflammasome inhibitor MCC950 was performed to evaluate FK manifestations following STING activity blockade. Furthermore, the impact of the STING agonist diABZI on FK progression was investigated. Compared to uninfected corneas, those infected with C. albicans exhibited increased expression of cGAS/STING signaling components, as well as its elevated activity. Inhibiting cGAS/STING signaling exacerbated the advancement of FK, as evidenced by elevated clinical scores, augmented fungal load, and heightened inflammatory response, including NLRP3 inflammasome activation and pyroptosis. Pharmacological inhibition of the NLRP3 inflammasome effectively mitigated the exacerbated FK by suppressing STING activity. Conversely, pre-activation of STING exacerbated FK progression compared to the PBS control, characterized by increased fungal burden and reinforced inflammatory infiltration. This study demonstrates the essential role of the cGAS/STING signaling pathway in FK pathogenesis and highlights the necessity of its proper activation for the host against FK.

Development of novel bisphenol derivatives with a membrane-targeting mechanism as potent gram-positive antibacterial agents

Antibiotic resistance is becoming increasingly severe. The development of small molecular antimicrobial peptides is regarded as a promising design strategy for antibiotics. Here, a series of bisphenol derivatives with amphiphilic structures were designed and synthesized as antibacterial agents by imitating the design strategy of antimicrobial peptides. After a series of structural optimizations, lead compound 43 was identified, which exhibited excellent antibacterial activity against Gram-positive bacterial strains (MICs = 0.78–1.56 μg/mL), poor hemolytic activity (HC50 > 200 μg/mL), and low cytotoxicity (CC50 > 100 μg/mL). Further biological evaluation results indicated that 43 exerted antibacterial effects by directly destroying bacterial cell membranes and displayed rapid bactericidal properties (within 0.5–1 h), leading to a very low probability of drug resistance. Moreover, in a murine model of corneal infection, 43 exhibited a strong in vivo antibacterial efficacy. These findings indicate that 43 is a promising candidate compound for the treatment of bacterial infections.

Crosstalk among miR-29, α-SMA, and TGFβ1/β3 in melatonin-induced exosome (Mel-prExo) treated human limbal mesenchymal stem cells (hLMSCs): An insight into scarless healing of the cornea.

Inflammatory mediators that infiltrate the corneal stroma after corneal infections, trauma or refractive surgery can trigger the transformation of corneal keratocytes into myofibroblasts, resulting in highly irregular collagen deposition and subsequently corneal scarring. Mesenchymal stem cells (MSCs) can be used as therapeutic agents to regenerate corneal and conjunctival tissue damage, regulate inflammation, and reduce the development of limbal stem cell failure. The use of MSC-derived exosomes as a cell-free therapeutic vector is a novel therapeutic approach. This study aimed to assess the effect of exosomes obtained from melatonin (Mel)-treated human limbal mesenchymal stem cells (hLMSCs) on naïve hLMSCs and to determine their influence on the antifibrotic and pro-regenerative pathways involved in corneal scarring. hLMSCs were treated with varying concentrations of Mel, followed by isolation and characterization of the procured exosomes (Mel-prExos). These exosomes were added to the cell culture media of naïve hLMSCs to examine their antifibrotic and pro-regenerative effects. The expression of miR-155, miR-29, TGFβ1, TGFβ3, PPARγ, and α-SMA miRNAs and genes were compared between Mel-treated hLMSCs and Mel-prExo-treated hLMSCs by using real-time PCR. We found that at 1 μM Mel and in the presence of Mel-prExos, TGFβ1 was expressed 0.001-fold, while TGFβ3 was expressed 0.6-fold. miR-29 expression was increased 38-fold in the control-Exo group compared to that in the control group. Changes in TGFβ1/β3 and α-SMA expression are associated with miR-29 and miR-155. This approach could prove beneficial for ocular surface tissue engineering applications.

Nanoemulsion Carriers for Ocular Fungal Infection: Main Emphasis on Keratomycosis.

Keratomycosis, also termed fungal keratitis (FK), is an invasive eye condition for which there is a lack of available effective treatment due to pharmacological shortages and vital ocular obstacles. This severe corneal infection typically suppurates and eventually ulcerates, ultimately causing blindness or decreased vision. According to epidemiological studies, FK is more common in warm, humid places with an agricultural economy. The use of nanoemulsion carriers for ocular fungal infection has been promoting better treatment and patient compliance. The persistent fungal infection like FK, affecting particularly the stroma heralds complications thereby posing difficulty in diagnosis and treatment. To help treat refractory cases and improve outcomes, recently targeted drug delivery techniques and novel antifungal drugs shall be explored. A delay in diagnosis may cause corneal fungal infections to have irreversible consequences, which cannot be avoided. However, infections can develop into ocular perforation even after receiving intense care. The commonly used chemotherapy for FK is based on topical (natamycin 5% is typically first-line therapy) and systemic administration of azole drugs. To address the problems related to better treatment, various nanoemulsion carriers were discussed. Novel drug delivery systems based on nanoemulsions are a viable therapeutic option for treating keratomycosis and may be a candidate method for overcoming obstacles in the treatment of many other ocular illnesses when combined with different hydrophobic medicines. With a brief explanation of the pathogenesis, this article seeks to give readers a thorough analysis of current trends, various treatment choices, and care strategies for fungal keratitis.

Ebselen improves fungal keratitis through exerting anti-inflammation, anti-oxidative stress, and antifungal effects

Fungal keratitis is a severely vision-threatening corneal infection, where the prognosis depends on both fungal virulence and host immune defense. Inappropriate host responses can induce substantial inflammatory damage to the cornea. Therefore, in the treatment of fungal keratitis, it is important to concurrently regulate the immune response while efforts are made to eliminate the pathogen. Ebselen is a widely studied organo-selenium compound and has been demonstrated to have antifungal, antibacterial, anti-inflammatory, and oxidative stress-regulatory properties. The effectiveness of ebselen for the treatment of fungal keratitis remains unknown. In this study, ebselen was demonstrated to produce a marked inhibitory effect on Aspergillus fumigatus (A. fumigatus), including spore germination inhibition, mycelial growth reduction, and fungal biofilm disruption. The antifungal activity of ebselen was related to the cell membrane damage caused by thioredoxin (Trx) system inhibition-mediated oxidative stress. On the contrary, ebselen enhanced the antioxidation of Trx system in mammalian cells. Further, ebselen was proven to suppress the expressions of inflammatory mediators (IL-1β, IL-6, TNF-α, COX-2, iNOS, and CCL2) and reduce the production of oxidative stress-associated indicators (ROS, NO, and MDA) in fungi-stimulated RAW264.7 cells. In addition, ebselen regulated PI3K/Akt/Nrf2 and p38 MAPK signaling pathways, which contributed to the improvement of inflammation and oxidative stress. Finally, we verified the therapeutic effect of ebselen on mouse fungal keratitis. Ebselen improved the prognosis and reduced the fungal burden in mouse corneas. Expressions of inflammatory mediators, as well as the infiltration of macrophages and neutrophils in the cornea were also obviously decreased by ebselen. In summary, ebselen exerted therapeutic effects by reducing fungal load and protecting host tissues in fungal keratitis, making it a promising treatment for fungal infections.

Small-diameter acellular porcine corneal stroma for peripheral corneal ulceration treatment.

To evaluate the clinical efficacy of small-diameter acellular porcine corneal stroma (SAPS) for the treatment of peripheral corneal ulceration (PCU). This retrospective clinical study included 18 patients (18 eyes) with PCU between April 2018 and December 2020. All patients had PCU and underwent lamellar keratoplasty with SAPS. Observation indicators included preoperative and postoperative best-corrected visual acuity (BCVA) and transparency of SAPS. The infection control rate in the surgical eye-lesion area was also calculated. Eighteen patients underwent lamellar keratoplasty with SAPS to treat PCU. None of the patients experienced rejection after 6mo (18/18) and 12mo (16/16) of follow-up. The BCVA (0.47±0.30) at the 6mo follow-up after operation was significantly improved compared with the baseline (0.99±0.80), and the difference was statistically significant (Z=-3.415, P<0.05). The BCVA at the 12mo follow-up after operation was not statistically significant compared to the 6mo (Z=0, P=1). With time, the SAPS graft gradually became transparent. At the 6mo (18/18) and 12mo (16/16) follow-up, none of the patients had recurrent corneal infection. SAPS is clinically effective in the treatment of PCU, improving the patient's BCVA and reducing the incidence of rejection after keratoplasty.

Overview of Mycotic Keratitis.

Keratomycosis is a serious corneal infection associated with high ocular morbidity that can lead to severe vision loss. It is estimated to affect more than 1 million patients annually, most commonly occurring in tropical climates, and represents a growing threat to patients worldwide. Despite aggressive medical management, fungal infections have a higher rate of perforation requiring surgical intervention compared with other infectious etiologies. Early diagnosis and appropriate treatment are keys to preserving vision and saving patients' eyes.Timely diagnosis of fungal keratitis helps minimize corneal damage and scarring and increases the likelihood of a favorable outcome. Studies have shown that correct identification of fungal infections is often delayed up to 2 to 3 weeks after initial presentation. This leads to incorrect or ineffective treatment for many patients. Diagnostic techniques explored in this study include corneal scrapings with staining and culture, visualization with in vivo confocal microscopy, molecular diagnostic techniques including polymerase chain reaction, and recently developed omics-based technologies.Treatment of fungal keratitis begins with topical antifungals. Medical management has been proven to be effective, but with limitations including poor drug penetration and low bioavailability. Cases that do not respond to topical therapy require more invasive and novel treatments to control the infection. We review the clinical trials that have shaped current practice patterns, with focus on the efficacy of topical natamycin as the primary therapy for filamentous fungal keratitis. We explore additional management strategies such as localized intrastromal and intracameral injections of antifungal medications, photodynamic therapy, and surgical intervention.

Management of bilateral lower eyelid entropion in a black Angus bull by temporary tacking and modified Hotz Celsus

AbstractThe objective was to evaluate the progression and management of eyelid tacking sutures before permanent eyelid surgical correction. A 1‐year‐old Aberdeen black Angus bull presented with a 1‐month history of bilateral corneal ulcers. Ophthalmic examination revealed an infected stromal corneal ulcer on the left eye and bilateral lower eyelid entropion. Lower eyelid tacking sutures were placed bilaterally to allow corneal healing, prevent recurrent corneal ulceration and allow resolution of concurrent moist dermatitis. Approximately 2 weeks after eyelid tacking, permanent entropion repair using a modified Hotz Celsus technique was performed on both lower eyelids. This report details the successful treatment of bilateral lower eyelid entropion in a bull using temporary tacking sutures to stabilise corneal and eyelid disease before permanent eyelid surgical correction.

Descemet’s membrane endothelial keratoplasty is the predominant keratoplasty procedure in Germany since 2016: a report of the DOG-section cornea and its keratoplasty registry

Background/aimsThis retrospective multicentric panel study provides absolute numbers, types of and indications for corneal transplantation in Germany from 2011 to 2021 and sets them into the international context.MethodsA questionnaire was...

Oral bacteria may affect conjunctival microorganisms in brachycephalic dogs: a preliminary study.

To evaluate the prevalence of oral bacteria in the conjunctiva of brachycephalic and nonbrachycephalic dogs. 12 brachycephalic (9.58 ± 3.55 years) and 12 nonbrachycephalic (8.33 ± 4.92 years) dogs without systemic disease, regardless of breed and sex, were included in the study, and half of the dogs in each group had periodontitis. This prospective study investigated clinical data including craniofacial ratio, ophthalmic examination results, and periodontal status of the included dogs. Bacterial samples were collected by swabbing the oral mucosa and conjunctival surfaces. The presence and quantity of bacteria were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 16S rRNA sequencing analysis, and the 10-fold dilution method. Statistical analyses were performed to assess correlations and factors influencing the presence of oral bacteria in the conjunctiva. The most common bacteria in the conjunctival flora in both groups were Micrococcus luteus, Corynebacterium spp, and Staphylococcus spp. The prevalence of oral bacteria on the conjunctival surface was 33%, with a significantly higher incidence in brachycephalic dogs (P = .027). Oral bacteria detected in the conjunctiva were predominantly Frederiksenia canicola, Neisseria spp, and Moraxella spp. Multiple regression analysis identified age, craniofacial ratio, and gingival index as factors influencing the presence of oral bacteria in the conjunctival flora. Oral resident bacteria have often been isolated from severe infectious corneal ulcers. This study provided evidence that brachycephalic dogs may require dental prophylaxis to reduce their oral bacterial load and that the association of oral bacteria in ocular diseases should be considered.

Commercial human 3D corneal epithelial equivalents for modeling epithelial infection in herpes keratitis

Herpes stromal keratitis is the leading cause of infectious blindness in the western world. Infection by HSV1 is most common, but VZV and hCMV also infect the cornea. Multiple models of HSV1 corneal infection exist, but none for VZV and hCMV because of their host specificity. Here, we used commercially available 3D human corneal epithelial equivalents (HCEE) to study infection by these herpesviruses. HCEE was infected by HSV-1 and hCMV without requiring scarification and resulted in spreading infections. Spread of HSV-1 infection was rapid, while that of hCMV was slow. In contrast, infections with VZV required damage to the HCEE and did not spread. Acyclovir dramatically reduced replication of HSV-1 in this model. We conclude that highly quality-controlled, readily available HCEE is a useful model to study human-restricted herpesvirus infection of the human corneal epithelium and for screening of antiviral drugs for treating HSK in an 3D model system.

The ecto-3′-nucleotidase activity of Acanthamoeba castellanii trophozoites increases their adhesion to host cells through the generation of extracellular adenosine

Acanthamoeba castellanii, a free-living amoeba, can be pathogenic to humans causing a corneal infection named Acanthamoeba keratitis (AK). The mannose-binding protein (MBP) is well established as the major factor related to Acanthamoeba pathogenesis. However, additional factors that participate in the adhesion process and protect trophozoites from cytolytic effects caused by host immune responses remain unknown. Ectonucleotidases, including 3′-nucleotidase/nuclease (3′-NT/NU), a bifunctional enzyme that was recently reported in A. castellanii, are frequently related to the establishment of parasitic infections. We verified that trophozoites can hydrolyze 3′-AMP, and this activity is similar to that observed in other protists. The addition of 3′-AMP increases the adhesion of trophozoites to LLC-MK2 epithelial cells, and this stimulation is completely reversed by DTT, an inhibitor of ecto-3′-nucleotidase activity. Lesions in corneal cells caused by AK infection may elevate the extracellular level of 3′-AMP. We believe that ecto-3′-nucleotidase activity can modulate the host immune response, thus facilitating the establishment of parasitic infection. This activity results from the generation of extracellular adenosine, which can bind to purinergic receptors present in host immune cells. Positive feedback may occur in this cascade of events once the ecto-3′-nucleotidase activity of trophozoites is increased by the adhesion of trophozoites to LLC-MK2 cells.

Burn-Induced Cicatricial Eyelid Retraction: A Challenging Case and Review of Management Principles.

Thermal and chemical burns can result in cicatricial eyelid retraction, characterized by an abnormal resting position of the eyelid margin and increased palpebral fissure height. Eyelid retraction often leads to exposure keratopathy, which can cause complications ranging from mild dry eye to globe-threatening ulceration and perforation. Prompt intervention includes aggressive lubrication, moisture chambers, eyelid tarsorrhaphy, and retraction repair surgery. Discussed here is a burn patient that developed severe cicatricial eyelid retraction and ectropion, leading to severe exposure keratopathy and infectious corneal ulceration with perforation. The patient required aggressive medical intervention, as well as 2 surgeries to restore the normal eyelid anatomy to protect the globe.

An Investigation of Keratoplasty Procedures and Their Outcomes in Iraq

Introduction: The treatment of corneal disorders involves the use of various forms of keratoplasty. The objective of this study was to provide a detailed description of the various types of keratoplasty procedures performed in Iraq, as well as their corresponding outcomes.&#x0D; Methods: An observational study was conducted at Al-Zahraa Teaching Hospital to document cases of keratoplasty. The collected data included age, gender, types of keratoplasty, indications, previous surgical or medical history, and postoperative outcomes. The types of keratoplasty included penetrating keratoplasty (PKP), deep anterior lamellar keratoplasty (DALK), and Descemet's stripping endothelial keratoplasty (DSEK). Additionally, we performed cataract surgery and intraocular lens (IOL) insertion for those with cataracts, using either IOLs with scleral fixation or IOLs with iris fixation. We complete the task on the first day following the purchase order, then the first week, the first month, and every six months thereafter. Prior to surgery, patients with corneal vascularization had laser photocoagulation of the blood vessels in the cornea.&#x0D; Results: Ages range from 4 to 90. People over 40 (60.8%) were the most common age group. The female prevalence was 52.9%. Right-eye illness was diagnosed 51.6% of the time. 60% of patients underwent PKP. 26.8% had DALK, 12.4% had DSEK. Post keratoplasty, the statistically-significant improvement-ratio was 68.5% as eyes best corrected visual acuity (BCVA) improvement, while 12.2% of eyes showed a decline in BCVA and 19.3% discharged with no changes in BCVA. Postoperatively, BCVA was significantly lower in cases with a duration below 1 year (1.5), and better among the duration &gt; 3 years (0.5). The greatest improvements were seen in cases with infective keratitis (-0.7), corneal dystrophies (-0.6), and advanced keratoconus (-0.7) whereas the lowest rates were documented in cases with a graft rejection (-0.3), and bullous keratopathy (-0.3)&#x0D; Conclusion: Keratoplasty is associated with a substantial enhancement of visual acuity in the younger population. Infective keratitis, keratoconus, and corneal dystrophy produce the most optimal and superior results. The PKP method is the most frequently performed.

Antimicrobial activity of cell-free supernatant derived from Ligilactobacillus animalis SWLA-1 in a novel ex vivo canine corneal infection model.

Canine bacterial keratitis is a corneal infection that causes various symptoms, including visual impairment, and necessitates eye removal in severe cases. Staphylococcus pseudintermedius is a pathogen that causes significant bacterial keratitis in canine patients. Moreover, multi-drug resistant Staphylococcus pseudintermedius (MDRSP) has been reported in both humans and animals. Regarding treatment failure against multi-drug resistant (MDR) pathogens with classic antibiotics, antimicrobial compounds derived from probiotics have been suggested as an alternative approach. Ligilactobacillus animalis SWLA-1 strain and its cell-free supernatant (CFS) have previously demonstrated potent antimicrobial activity against various MDR pathogenic bacteria. Based on this finding, we evaluated the anti-staphylococcal activity of CFS derived from Ligilactobacillus animalis SWLA-1 against MDRSP in a newly established ex vivo canine corneal infection model using fresh canine corneoscleral rims. Additionally, an in vitro cytotoxicity test using human keratocytes was performed. CFS significantly inhibited the growth of MDRSP in the novel ex vivo model and did not exhibit any significant toxicity against keratocytes in vitro. Based on these results, the antimicrobial compounds in CFS show potential as a novel approach for MDR staphylococcal keratitis treatment.

Distribution of pathogenic bacteria and antimicrobial sensitivity of eye infections in Suzhou.

To investigate the types of bacteria in patients with eye infections in Suzhou and their drug resistance to commonly used antibacterial drugs. The clinical data of 155 patients were retrospectively collected in this study, and the pathogenic bacteria species and drug resistance of each pathogenic bacteria were analyzed. Among the 155 patients (age from 12 to 87 years old, with an average age of 57, 99 males and 56 females) with eye infections (160 eyes: 74 in the left eye, 76 in the right eye and 5 in both eyes, all of which were exogenous), 71 (45.81%) strains were gram-positive bacteria, 23 (14.84%) strains were gram-negative bacteria and 61 (39.35%) strains were fungi. Gram-positive bacteria were highly resistant to penicillin and erythromycin (78.87% and 46.48% respectively), but least resistant to vancomycin at 0. Gram-negative bacteria were highly resistant to cefoxitin and compound sulfamethoxazole (100% and 95.65% respectively), but least resistant to meropenem at 0. Comparison of the resistance of gram-positive and gram-negative bacteria to some drugs revealed statistically significant differences (P<0.05) in the resistance of both to cefoxitin, cotrimoxazole, levofloxacin, cefuroxime, ceftriaxone and ceftazidime, and both had higher rates of resistance to gram-negative bacteria than to gram-positive bacteria. The distribution of bacterial infection strains showed that Staphylococcus epidermidis was the most common strain in the conjunctiva, cornea, aqueous humor or vitreous body and other eye parts. Besides, Fusarium and Pseudomonas aeruginosa were also among the most common strains of conjunctival and corneal infections. Gram-positive bacteria are the dominant bacteria in eye infections, followed by gram-negative bacteria and fungi. Considering the resistance of gram-negative bacteria to multiple drugs, monitoring of bacteria should be strengthened in eye bacterial infections for effective prevention and control to reduce complications caused by eye infections.