Corneal Swabs Research Articles

The use of human albumin eye drops as an adjunctive therapy in cases of persistant corneal epithelial defects

Background Albumin eye drops (AED) can be effective in the healing of corneal epithelial defects. Albumin is the main protein component of autologous serum and therefore may be useful in the treatment of ocular surface diseases such as corneal ulcers and epithelial defects. Aim This work aimed to study the effect of human AED as adjunctive therapy in the treatment of persistent corneal epithelial defects (PCEDs). Patients and methods This prospective study was conducted in 20 patients aged 18–60 years, of both sexes, with PCEDs that did not respond to standard medical treatment for 10 to 14 days. All patients underwent slit-lamp examination, fundus examination, intraocular pressure measurement (digital), corneal swab, culture, and sensitivity. Results There was a significant positive correlation between the duration of medical therapy with the persistent antiepithelial defect AED and the size of the persistent epithelial defect at presentation (P<0.05). There was significant improvement in pain sensation, ciliary injection, persistent epithelial defect size, corneal, and stromal infiltration during the study period. There was no significant association between the duration of continuous ant epithelial drug therapy AED and stromal infiltration at presentation (P=0.627). Conclusion The promising therapeutic effects of AED on the corneal epithelium have been demonstrated. Albumin has shown a therapeutic effect in the treatment of PCEDs.

Clinical and Etiology Presentations of Keratitis Caused by Mixed Infectious Agents (Bacteria and Fungi)

Introduction: Microbiological studies following the culture of corneal infiltrates are the gold standard for determining the etiology of infectious keratitis caused by bacteria or fungi; however, even if a culture of the corneal ulcer is obtained. Purpose: To investigate the predisposing factors and clinical and Etiology presentations of keratitis caused by mixed infectious agents (bacteria and fungi). Methods: This was a prospective study of cases with mixed bacterial and fungal keratitis, done between July to December 2022 in Department of Ophthalmology, Netraloy Eye Care Center, Thanthania, Bogura Sadar, Bogura, Bangladesh. Sixty (60) cases of mixed bacterial and fungal keratitis were identified. Samples (corneal swabs and scrapings) were collected aseptically from corneal ulcer patients. Isolation and identification of the microbial agents and antimicrobial susceptibility testing were done in the Microbiology and Pathology departments. Results: 38 cases (63.3%) were men, and the mean age was 54.2±9.3 years. The affected people were mostly (50; 83.3%) residing in the rural areas. 34 patients (56.7%) were involved in agricultural activities. The people of 41- 60 years of age were particularly prone to this disease (40; 66.7%). The most common predisposing factor for mixed keratitis was a history of ocular trauma (42; 70%) and 28 patients (46.7%) had a history of trauma with vegetative matter. The incidence of the disease was highest in the monsoon season, between June to September (32; 53.3%). The most common causative bacterial organisms was Staphylococcus aureus (26;43.3%) followed by Pseudomonas secies (10;16.7%) and among fungal organisms was Aspervgillus fumigates (22;36.7%) followed by Fusarium species (12;20%). Conclusion: The identification of the etiology and the predisposing factors of corneal ulcers in this region are important for the prevention and early treatment of the disease. Usually, patients with mixed bacterial and fungal keratitis have poor prognosis. Thus, when the infectious keratitis is running an atypical course or found unresponsive to the initial medical treatment, the possibility of a mixed infection by bacterial and fungal organisms should be considered.

Phenotypic Screening and Antibiogram of Infectious Ulcerative Keratitis Cases in Tripoli Eye Hospital, Libya

Aims: This study to investigate the most prevalent pathogens that cause corneal ulcer in Tripoli-Libya, and to recognize the antibiogram of the isolated pathogens Study Design: This study was a prospective study performed in eye hospital (Zawyet-Aldahmany eye hospital). Place and Duration of Study: It was conducted at the microbiology laboratory of the hospital over a year from December 2018 to January 2020, The overall size of the sample enrolled in this study was 50 inpatients in the admission department, which was taken according to the incidence of the corneal ulceration cases admitted to the hospital. Methodology: The corneal scrapings and swabs were collected and subjected to microbiological examination. Demographic data and risk factors were collected for each patient. The antibiotic susceptibility of the bacterial microorganisms was determined by the Kirby-Bauer disk diffusion method, to identify the most appropriate antibiotic for each bacterial isolate. Results: 60% of the patients were males, the mean age of the patients was 46.5 years, unilateral right eye keratitis was involved in (54%) of cases, trauma was the major risk factor (24%), followed by systemic disease (14%). Concerning the seasonal distribution of the cases between months, our study revealed that summer and winter seasons in Libya (January, July, August, and September) involved most of the cases, and interestingly, fungal keratitis (Aspergillus) was higher in (July, August), which is the summer season in Libya. The culture positive rate was (80%), of which (36%) were bacterial, and (22%) were fungal pathogens, and the other (22%) were mixed fungal and bacterial cultures. The most common bacterial isolate was (26%) P.aeruginosa and (16%) staphylococcus aureus, while Aspergillus (40%) was the most common fungal isolate, followed by Penicillium and fusarium species. Our results showed that P.aeruginosa was the responsible microorganism for rapid keratitis progression in three cases who were using cosmetic lenses promptly. Concerning antibiotic sensitivity, all gram-negative bacteria and positive isolates were susceptible to old-generation fluoroquinolones such as ciprofloxacin and levofloxacin, while ceftazidime showed resistance to penicillins. Conclusion: In conclusion, with early suspicion and microbiological diagnostic procedures, appropriate therapy can only reduce the incidence of this threatening ocular case.

A Mystery Unsolved: A Spontaneous Lens and Uveal Prolapse in a New-born

Introduction : Corneal rupture in new-born, especially during the first week of life is rare. Some of these cases occur because of ocular trauma during deliveries, systemic infection, and congenital anomalies. We aim to deliver a rare case of spontaneous lens and uveal prolapse in new-born and management in treating the case.
 Case Illustration : A-2-day-old full-term-baby was referred due to bleeding of the right eye 6 hours post-partum by spontaneous vaginal delivery with no trauma. The mother, a 23-year-old, having the second born with no history of medical illness or vaginal discharged during pregnancy. Measurements of birth weight and length were normal. Eye examination of the right eye (RE) was uveal and lens prolapse and left eye (LE) cloudy cornea with leukoma and prominent neovascularization. Orbital CT-Scan revealed bilateral vitreous bleeding of both eyes. Laboratory examination showed reactive IgM for herpes simplex virus, reactive IgG for both toxoplasma and rubella. Corneal swab culture was sterile. Systemic and topical antibiotics were administered then switched to systemic antivirus. The 12-day-old-patient showed partial epithelization of cornea, less uveal volume with it partially shrank. Close observation was conducted and evisceration was postponed.
 Discussion : Although etiologic work-up has been addressed, exact etiology remains unknown with the possibility of congenital cause. It has been postulated that structurally malformed eyes are more prone to corneal perforations. Management should be personalized based on the patient’s need.
 Conclusion : Thorough examination is vital a rare case with undisclosed aetiology especially new-born. Patient monitoring is sufficient if no infections and bleedings found.

MANAGEMENT OF CORNEAL ULCER PRESENTED WITH RARE PATHOGEN : STREPTOCOCCUS MITIS

Introduction : Corneal ulcers can arise from various corneal diseases, including infections, inflammation, and autoimmune disease. Staphylococcus aureus is the most common bacterial pathogen, but lesser- known bacteria like Streptococcus mitis can also cause corneal ulcers. Accurate diagnosis and treatment are essential to prevent vision loss and complications.
 Case Illustration : A 19-year-old female patient presented with a chief complaint of white spots on her right eye for three months. Previously, her right eye was hit by a foreign object and subsequently, the patient experienced redness and pain in the affected eye. One week later, white spot appeared in the patient's eye and reported to enlarge in the last month. The patient also complained of pain, blurry vision with visual acuity of 1/300, redness, glare, and a foreign body sensation. Corneal swab culture discovered Streptococcus mitis to be the causative agent. The patients was given hourly drop of topical levofloxacin. One month after initial treatment, patient’s symptoms was improving with visual acuity of 6/60 on her affected eye and the ulcer was healed.
 Discussion : Streptococcus mitis is a commensal pathogen in oral cavity and not normally cause infection of ocular tissue. It may cause ulcer due to prolonged use of topical steroid and previous ocular trauma, since Streptococcus mitis had low virulence rate.
 Conclusion : Corneal scraping culture should be carried out before treatment of infectious corneal ulcer. Streptococcus mitis is considered rare for corneal ulcer pathogen. Topical quinolones are the first- line drug for bacterial corneal ulcer and worked exceptional for wide range of bacteria.

The role of naturally acquired intracellular Pseudomonas aeruginosa in the development of Acanthamoeba keratitis in an animal model.

Acanthamoeba is an environmental host for various microorganisms. Acanthamoeba is also becoming an increasingly important pathogen as a cause of keratitis. In Acanthamoeba keratitis (AK), coinfections involving pathogenic bacteria have been reported, potentially attributed to the carriage of microbes by Acanthamoeba. This study assessed the presence of intracellular bacteria in Acanthamoeba species recovered from domestic tap water and corneas of two different AK patients and examined the impact of naturally occurring intracellular bacteria within Acanthamoeba on the severity of corneal infections in rats. Household water and corneal swabs were collected from AK patients. Acanthamoeba strains and genotypes were confirmed by sequencing. Acanthamoeba isolates were assessed for the presence of intracellular bacteria using sequencing, fluorescence in situ hybridization (FISH), and electron microscopy. The viability of the bacteria in Acanthamoeba was assessed by labelling with alkyne-functionalized D-alanine (alkDala). Primary human macrophages were used to compare the intracellular survival and replication of the endosymbiotic Pseudomonas aeruginosa and a wild type strain. Eyes of rats were challenged intrastromally with Acanthamoeba containing or devoid of P. aeruginosa and evaluated for the clinical response. Domestic water and corneal swabs were positive for Acanthamoeba. Both strains belonged to genotype T4F. One of the Acanthamoeba isolates harboured P. aeruginosa which was seen throughout the Acanthamoeba's cytoplasm. It was metabolically active and could be seen undergoing binary fission. This motile strain was able to replicate in macrophage to a greater degree than strain PAO1 (p<0.05). Inoculation of Acanthamoeba containing the intracellular P. aeruginosa in rats eyes resulted in a severe keratitis with increased neutrophil response. Acanthamoeba alone induced milder keratitis. Our findings indicate the presence of live intracellular bacteria in Acanthamoeba can increase the severity of acute keratitis in vivo. As P. aeruginosa is a common cause of keratitis, this may indicate the potential for these intracellular bacteria in Acanthamoeba to lead to severe polymicrobial keratitis.

Peripheral sterile corneal infiltrate after cross linking in keratoconus: A case report

Aims/Purpose: The aim of our work is to describe the clinical aspect of sterile corneal infiltrates after cross linking and to evaluate the risk factors involved in their occurrence.Methods: We report the case of a young girl, followed for bilateral keratoconus having made a cross linking which was complicated by sterile catarrhal infiltrates.Results: This is a 15 years old girl, followed for allergic conjunctivitis with notion of self‐medication. The ophthalmological examination on admission found a visual acuity with correction counting fingers at 1 metre in oculus uterque (OU), some conjunctival papillae, minimal blepharitis, clear cornea, cortico‐nuclear cataract ocular tone was 10 mmHg in OU, normal fundus in OU. A corneal topography was performed showing signs of bilateral keratoconus classified as stage III according to the Krumeich classification. An emergency cross linking was indicated in OU starting with the OL, the patient was put on a topical antibiotic treatment, artificial tears with a daily control. At 4 days post‐op, the cornea had completely re‐epithelialized with the presence of a slight central haze and the appearance of 2 inferior stromal opacities of 1 mm/1 mm associated with a crescent infiltrate and 2 similar superior stromal opacities taking the fluorescent in front of the free edge. A corneal swab was taken for bacteriological, mycological and parasitological study and came back negative. The patient was initially put on ceftazidime and vancomycin based eye drops with a blepharitis treatment based on azyter collyrium lavage and artificial tear. The examination 48 h later showed persistence of stromal opacities without taking fluo. A local corticosteroid therapy was started with strict monitoring. The evolution was marked by an almost total regression of the stromal opacities and a disappearance of the central haze. The diagnosis of sterile infiltrate was made in view of the marked clinical improvement under local corticosteroid therapy and the absence of germs in the corneal sample.Conclusions: Evaluation of risk factors showed that epithelial injury may be the common pathway in pathogenesis, as no sterile infiltrate in Epi‐on CXL occurred, and postoperative NSAIDs use increased the risk of developing sterile infiltrates approximately fourfold.

Ocular surface immune transcriptome and tear cytokines in corneal infection patients.

Microbial keratitis is one of the leading causes of blindness globally. An overactive immune response during an infection can exacerbate damage, causing corneal opacities and vision loss. This study aimed to identify the differentially expressed genes between corneal infection patients and healthy volunteers within the cornea and conjunctiva and elucidate the contributing pathways to these conditions' pathogenesis. Moreover, it compared the corneal and conjunctival transcriptomes in corneal-infected patients to cytokine levels in tears. Corneal and conjunctival swabs were collected from seven corneal infection patients and three healthy controls under topical anesthesia. RNA from seven corneal infection patients and three healthy volunteers were analyzed by RNA sequencing (RNA-Seq). Tear proteins were extracted from Schirmer strips via acetone precipitation from 38 cases of corneal infection and 14 healthy controls. The cytokines and chemokines IL-1β, IL-6, CXCL8 (IL-8), CX3CL1, IL-10, IL-12 (p70), IL-17A, and IL-23 were measured using an antibody bead assay. A total of 512 genes were found to be differentially expressed in infected corneas compared to healthy corneas, with 508 being upregulated and four downregulated (fold-change (FC) <-2 or > 2 and adjusted p <0.01). For the conjunctiva, 477 were upregulated, and 3 were downregulated (FC <-3 or ≥ 3 and adjusted p <0.01). There was a significant overlap in cornea and conjunctiva gene expression in patients with corneal infections. The genes were predominantly associated with immune response, regulation of angiogenesis, and apoptotic signaling pathways. The most highly upregulated gene was CXCL8 (which codes for IL-8 protein). In patients with corneal infections, the concentration of IL-8 protein in tears was relatively higher in patients compared to healthy controls but did not show statistical significance. During corneal infection, many genes were upregulated, with most of them being associated with immune response, regulation of angiogenesis, and apoptotic signaling. The findings may facilitate the development of treatments for corneal infections that can dampen specific aspects of the immune response to reduce scarring and preserve sight.

Bacterial and fungal isolates from 107 cases of ulcerative keratitis in Japanese Thoroughbred racehorses (2017–2021)

Infectious ulcerative keratitis is a common disease in racehorses. To improve treatment outcomes, this study aimed to assess the antimicrobial susceptibilities of bacterial and fungal isolates obtained from the cornea of Japanese Thoroughbred racehorses with equine infectious ulcerative keratitis. Bacterial and fungal cultures were performed for 166 corneal swabs from 107 cases. A disc diffusion test and minimum inhibitory concentration test were also performed to assess antimicrobial susceptibility of the bacterial and fungal isolates, respectively. Bacterial and/or fungal isolates were obtained from 85.0% (91/107) of the cases. Staphylococcus was primarily isolated from bacterial isolates, including methicillin-resistant Staphylococcus aureus (MRSA), Aerococcus, Streptococcus, Acinetobacter, and Pseudomonas. Aspergillus was primarily isolated from filamentous fungi, and Debaryomyces species was primarily identified in yeast-like fungi. Ofloxacin resistance was observed in 100% (12/12), 15.9% (7/44), and 25.0% (3/12) of MRSA, Staphylococcus, and Streptococcus isolates, respectively. The prevalence of quinolone-resistant Staphylococci and Streptococci has increased in the past two decades. All Aspergillus isolates were susceptible to voriconazole, whereas other filamentous fungi, including Fusarium, were less susceptible to voriconazole. Further studies are required to determine effective treatments for antimicrobial-resistant isolates.

Rapid Point-of-Care Identification of Aspergillus Species in Microbial Keratitis

Microbial keratitis (MK) is a common cause of unilateral visual impairment, blindness, and eye loss in low-income and middle-income countries. There is an urgent need to develop and implement rapid and simple point-of-care diagnostics for MK to increase the likelihood of good outcomes. To evaluate the diagnostic performance of the Aspergillus-specific lateral-flow device (AspLFD) to identify Aspergillus species causing MK in corneal scrape and corneal swab samples of patients presenting with microbial keratitis. This diagnostic study was conducted between May 2022 and January 2023 at the corneal clinic of Aravind Eye Hospital in Madurai, Tamil Nadu, India. All study participants were recruited during their first presentation to the clinic. Patients aged 15 years or older met the eligibility criteria if they were attending their first appointment, had a corneal ulcer that was suggestive of a bacterial or fungal infection, and were about to undergo diagnostic scrape and culture. Sensitivity and specificity of the AspLFD with corneal samples collected from patients with MK. During routine diagnostic scraping, a minimally invasive corneal swab and an additional corneal scrape were collected and transferred to aliquots of sample buffer and analyzed by lateral-flow device (LFD) if the patient met the inclusion criteria. Photographs of devices were taken with a smartphone and analyzed using a ratiometric approach, which was developed for this study. The AspLFD results were compared with culture reports. The 198 participants who met the inclusion criteria had a mean (range) age of 51 (15-85) years and included 126 males (63.6%). Overall, 35 of 198 participants with corneal scrape (17.7%) and 17 of 40 participants with swab samples (42.5%) had positive culture results for Aspergillus species. Ratiometric analysis results for the scrape samples found that the AspLFD achieved high sensitivity (0.89; 95% CI, 0.74-0.95), high negative predictive value (0.97; 95% CI, 0.94-0.99), low negative likelihood ratio (0.12; 95% CI, 0.05-0.30), and an accuracy of 0.94 (95% CI, 0.90-0.97). Ratiometric analysis results for the swab samples showed that the AspLFD had high sensitivity (0.94; 95% CI, 0.73-1.00), high negative predictive value (0.95; 95% CI, 0.76-1.00), low negative likelihood ratio (0.07; 95% CI, 0.01-0.48), and an accuracy of 0.88 (95% CI, 0.73-0.96). Results of this diagnostic study suggest that AspLFD along with the ratiometric analysis of LFDs developed for this study has high diagnostic accuracy in identifying Aspergillus species from corneal scrapes and swabs. This technology is an important step toward the provision of point-of-care diagnostics for MK and could inform the clinical management strategy.

Adjuvant Topical Interferon Alpha 2b for the Treatment of Monkeypox Ocular Manifestations.

The aim of this study was to report a case of ocular Mpox that responded favorably to treatment with topical interferon and oral doxycycline. This is a case report of a previously healthy 24-year-old woman who developed a pustular rash, headache, fever, arthralgia, sore throat, and asthenia 3 weeks before attending to our clinic. Her main complaint at the moment of the visit was pain, photophobia, foreign body sensation, blurred vision, red eye, and discharge on the left eye. The slit-lamp examination of the left eye showed severe conjunctival hyperemia associated with tarsal follicles, 360 degrees ciliary injection, diffuse corneal epithelial edema with white linear epithelial infiltrates, pigmented and nonpigmented keratic precipitates, and two 1-mm peripheral corneal ulcers with white infiltrates, associated with positive fluorescein staining. Anterior chamber cellularity and flare were mildly present. Mpox with ocular manifestations diagnosis was confirmed by real-time quantitative reverse transcription polymerase chain reaction assay (qRT-PCR) testing; samples were taken from corneal, conjunctival, and nasopharynx swab as well as a skin scab. Topical interferon alpha 2b 1 MIU/mL every 6 hours for 1 month and oral doxycycline 100 mg BID were administered along with other medications with consequent decrease of inflammation and malaise symptoms 1 week later, associated with uncorrected visual acuity improvement. Alternative and efficacious treatment options for Mpox ocular manifestations are needed to prevent further disease progression and sequelae in countries with no access to the gold-standard therapy. Topical interferon alpha 2b and oral doxycycline have shown adequate response as shown with this patient.

English

This study aimed to describe the clinical course of SA-MCF and the duration of viremia in surviving cattle and to perform the phylogenetic analysis of the tegument protein gene of OvHV-2 in cattle in the Central Balkan. A farm housing two heifers and 7 sheep with a confirmed SA-MCF case were selected for the investigation. For the estimation of the length of viremia and the virus shedding, the animals were sampled repeatedly, weekly for two months. For the phylogenetic analysis, a retrospective study was performed on 21 samples from cattle, and 7 samples from sheep, from the Central Balkan. In the blood samples of the survived heifer, the OvHV-2 genome was detected until week 7, in corneal swabs, the OvHV-2 genome was detected until week 6, and in nasal swabs until week two of the study. A retrospective study revealed that out of 21 tested cattle, OvHV–2 was detected in 15 (71.4%), and out of 7 tested sheep, three (42.9%) were positive. The sequenced samples show the highest percentage of similarity with the strains from Brasil KJ658293.1 (100%) and Germany HM216475.1 (100%).. Since there is a variety of different clinical signs similar to other notifiable diseases such as BVD, IBR, and FMD, there is a clear benefit in including SA-MCF in the differential diagnosis in cattle. As mixed farming in the Central Balkan is practiced, implementing SA-MCF monitoring in passive surveillance would allow a better understanding of the disease, ascertaining its prevalence and could provide new information regarding SA-MCF epidemiology

Comparison of Culture Results between Specimens from Corneal Scraping with Microhomogenization and Corneal Swab in Moderate and Severe Bacterial Corneal Ulcers.

The purpose of this study was to compare the bacterial culture results from corneal infiltrate specimens collected using two different methods, corneal scraping followed by microhomogenization and corneal swab. This is a comparative crosssectional study, with 18 participants undergoing corneal specimen collection using each of the 2 sampling techniques. The results from the scraping and swab methods were separated and then compared using data analysis. The proportion of Gram stain results that matched the culture results for the scraping-microhomogenization technique was 6/13 (46.2%), and the proportion of Gram stain results that matched the culture results for the swab technique was 5/13 (38.5%) (McNemar test P value, 1.000; P > 0.05). The proportion of positive cultures obtained using the scraping-microhomogenization technique was 13/18 (72.2%), and the proportion of positive cultures obtained using the swab technique was 9/18 (50%) (McNemar test P value, 0.219; P > 0.05). The Kappa suitability test value for comparison of the scraping-microhomogenization technique to the corneal swab was 0.333. The specimens collected by corneal scraping followed by microhomogenization had a higher positive bacterial culture rate than those collected by corneal swab, but the results were not statistically significant. IMPORTANCE This study aimed to compare the culture results between scraping specimens with microhomogenization and corneal smears in patients with moderate to severe bacterial corneal ulcers. This study could be a guideline for treating bacterial corneal ulcers.

Antibiotic Recommendations for Treatment of Canine Stromal Corneal Ulcers.

The aim of the study was to identify the aerobic bacterial isolates and determine corresponding antibiotic susceptibility profiles in vitro in canine clinical specimens with stromal corneal ulcers, with the goal of providing recommendations for first-line treatment with antibiotics. A total of 198 canine corneal stromal ulcer samples were studied between 2018 and 2021. A corneal swab was collected and cultured under aerobic conditions. Bacterial organisms were identified at the species level by MALDI-TOF mass spectrometry. Antibiotic susceptibility testing for commonly used topical and systemic antibiotics was performed by disk diffusion. Bacterial growth was obtained from 80% of samples. A variety of bacterial species were identified wherein the most common specimens were represented by Staphylococcus pseudintermedius (22%), Staphylococcus epidermidis (12%), Staphylococcus capitis (11%), and Pseudomonas aeruginosa (10%). Based on the overall antibiotic susceptibility data, neopolybac alone (96%) or a combination of neopolybac with either ofloxacin or amikacin (each 99%) showed the best coverage for commonly isolated bacterial organisms from canine corneal stromal ulcers. Results of this study support the use of the combined antibiotics as the first-line response for the treatment of canine corneal stromal ulcers. A statically significant increase in acquired bacterial resistance was detected during the longitudinal data observation.

Assessment of quinolone resistance in bacteria isolated from corneal ulcers in dogs

Corneal ulcers or ulcerative keratitis is the loss of continuity of corneal epithelium leading to exposure of corneal stroma. It is a highly painful condition in dogs. The common aetiological agents responsible for this condition are bacteria and for treatment, antibiotics are widely used. Indiscriminate and prolonged use of antibiotics can cause antimicrobial resistance (AMR) in bacteria. The present communication deals with the isolation of bacteria from corneal ulcers in dogs and the assessment of quinolone resistance. A total of 15 corneal swab samples were collected from dogs suffering from corneal ulcers, presented to the Department of Veterinary Surgery and Radiology, Teaching Veterinary Clinical Complex, College of Veterinary and Animal Sciences, Mannuthy. They were inoculated on to brain heart infusion agar as well as blood agar and incubated at 37 °C for 24 h for the isolation of aerobic bacteria. Eighteen isolates obtained were then subjected to antibiotic susceptibility test by disc diffusion method using the quinolone group of antibiotics, viz. ciprofloxacin, enrofloxacin, ofloxacin and moxifloxacin. Majority of the isolates exhibited varying resistance to these antibiotics. Polymerase chain reaction was performed to amplify gyrA gene, which is reported to be one of the reasons responsible for quinolone resistance with respect to its mutation. Seven out of the 18 isolates amplified gyrA gene. The amplicon obtained corresponding to a representative sample, which was found resistant by disc diffusion method was sequenced and a single point mutation was detected.

Trends in antibiotic resistance in ocular samples in a tertiary eye centre in Saudi Arabia in 2003–2019

ObjectifLa présente étude visait à analyser l'antibiorésistance dans des échantillons oculaires recueillis pendant 16 ans. MéthodesIl s'agissait d'une étude de cohorte rétrospective réalisée à l'hôpital King Khaled, spécialisé en ophtalmologie, situé à Riyad, en Arabie Saoudite, entre 2003 et 2019. On y a examiné des écouvillonnages cornéens et conjonctivaux de même que des échantillons aqueux et vitréens. RésultatsOn a observé une tendance significative vers une augmentation de la résistance des staphylocoques à coagulase négative au fil du temps envers l’érythromycine (p < 0,001), l'oxacilline (p < 0,001), l'acide fusidique (p < 0,001) et la moxifloxacine (p = 0,003). Staphylococcus aureus a également présenté une hausse significative de ses profils de résistance envers l'oxacilline (p = 0,001), l'ofloxacine (p = 0,003) et la moxifloxacine (p = 0,001). Streptococcus pneumoniæ, pour sa part, a manifesté une augmentation significative de ses profils de résistance envers l’érythromycine (p = 0,01) et l'ofloxacine, soit de 0,80 % en 2003 à 80 % en 2019 (p = 0,015). On n'a enregistré aucune hausse statistiquement significative de l'antibiorésistance de Pseudomonas. ConclusionsOn a observé une augmentation des profils d'antibiorésistance, notamment dans le cas des microorganismes gram-positifs. Compte tenu de ces résultats, il serait judicieux de réviser les stratégies habituelles de prescription des antibiotiques à usage oculaire et d'envisager le recours à des antibiotiques différents.

The Role of Topical Povidone-Iodine in the Management of Infectious Keratitis: A Pilot Study.

The aim of this prospective explorative study was to evaluate the safety and the effectiveness of topical polyvinylpyrrolidone-iodine (PVP-I) administered during the time-to-results period for pathogen identification and susceptibility testing in patients with infectious keratitis (IK). A corneal swab (CS) for antimicrobial evaluation was performed at enrollment (T0) and topical 0.66%-PVP-I was administered until the laboratory results were available (T1). Ulcer and infiltrate areas and infiltrate depths were compared between T0 and T1 (i.e., time-to-result period). Patients were then shifted to a specific antimicrobial therapy and followed up until resolution of their infiltrates (Tlast-TL). Twenty-five eyes were enrolled, and none showed clinical worsening leading to protocol withdrawal. At T1, ulcer and infiltrate areas showed significant improvement in Gram-positive IK (n = 13–52%; p = 0.027 and p = 0.019, respectively), remained stable in fungal IK (n = 5–20%; both p = 0.98) and increased in those with Gram-negative bacteria (n = 4–16%; p = 0.58 and p = 0.27). Eyes with negative cultures (n = 3–12%) showed complete resolution at T1 and did not initiate any additional antimicrobial therapy. The administration of 0.66% PVP-I during the time-to-result period seems to be a safe strategy in patients with IK while often sparing broad-spectrum antimicrobial agents. In addition, it showed to be effective in eyes with a Gram-positive bacterial infection.

Impact of Sample Collection Order on the Diagnostic Performance of Metagenomic Deep Sequencing for Infectious Keratitis.

The purpose of this article was to evaluate the impact of sample collection order on the diagnostic yield of metagenomic deep sequencing (MDS) for determining the causative pathogen in infectious keratitis. We performed a cross-sectional diagnostic test evaluation among subjects with infectious keratitis at Aravind Eye Hospital in Madurai, India. All subjects underwent corneal scrapings of the affected eye to obtain potassium hydroxide smear, Gram stain, bacterial culture, and fungal culture, in this order. The order of MDS specimen collection relative to smear and culture samples was randomized and served as the primary predictor. Outcomes included the normalized copy number of pathogenic RNA detected by MDS, the proportion of MDS samples that were diagnostic, and the agreement of MDS results with cultures. MDS samples from 46 subjects with corneal ulcers were evaluated. MDS was positive in 33 subjects (76%) and had 74% overall agreement with culture results. There was no association between order of MDS sample collection and normalized copy number of genetic material detected (P = 0.62) or the likelihood of MDS positivity (P = 0.46). However, the likelihood of agreement between MDS and cultures decreased when MDS corneal swabs were collected after other diagnostic corneal scrapings (P = 0.05). The overall yield of MDS for detecting the cause of infectious keratitis was not affected by sample collection order. However, diagnostic agreement between MDS and cultures decreased when MDS samples were collected after other specimens. Additional investigation is warranted to determine whether this represents increased sensitivity of MDS compared with cultures or higher susceptibility to contaminants.

Prevalence and Antibiotic Susceptibility of Bacterial Isolates From Dogs With Ulcerative Keratitis in Midwestern United States.

The objective of this study was to describe bacterial culture and antibiotic susceptibility results in 476 dogs presenting with suspected bacterial keratitis in Iowa and surrounding Midwestern states, further detailing trends in patient characteristics, seasonality, and antimicrobial resistance. Corneal swabs yielded 465 bacterial isolates and 220 cultures (46.2%) with no apparent growth (0–5 isolates per culture). The most frequent bacterial genera were Staphylococcus (32.3%), Streptococcus (19.1%), and Pseudomonas (12.5%), while the most common bacterial species were Staphylococcus pseudintermedius (26.7%), Streptococcus canis (12%), and Pseudomonas aeruginosa (7.5%). Compared to mixed-breed dogs, canine breeds most likely to be examined for ulcerative keratitis included Boston terrier, Cavalier King Charles spaniel, miniature pinscher, pug, rat terrier, Saint Bernard, shih tzu, and silky terriers. In summer, the likelihood to yield a negative culture was reduced while the likelihood to culture Pseudomonas species was increased. Bacteria considered multidrug resistant (MDR, resistant to ≥ 3 antibiotic classes) represented 20% of all canine isolates and were most prevalent for Staphylococcus species (33%). An alarming, escalating trend of MDR prevalence was noted between 2016 (5%) and 2020 (34%). Individual ophthalmic preparations (i.e., single antibiotics or commercially available antibiotic combinations) with highest efficacy against all bacterial isolates included chloramphenicol (83%), ceftiofur (79%), amikacin (77%), neomycin-polymyxin B-bacitracin (77%), and gentamicin (74%). Efficacy of systemic antibiotics and combinations of ophthalmic preparations was also evaluated. Based on the present findings, triple antibiotic (Neo-Poly-Bac) is recommended as empirical monotherapy for prophylactic antibiotic therapy in dogs with simple corneal ulcers, while a chloramphenicol-ciprofloxacin combination is empirically recommended for therapeutic management of infected corneal ulcers. Pending culture and susceptibility results, appropriate selection of empiric antibiotic therapy is important to enhance therapeutic outcome and reduce antibacterial resistance in dogs with corneal ulceration.

Bacterial pathogens in conjunctivitis and corneal ulcers with special reference to Streptococcus pneumoniae, in early 2008, in the National Eye Hospital, Sri Lanka

Introduction: The most important and frequently occurring eye infections are conjunctivitis and corneal ulcers. Though the significance of Streptococcus pneumoniae in eye infections is well-known, identification of causative serotypes is important for comparison with serotypes causing invasive diseases. Objectives: To describe the spectrum and characteristics of bacterial pathogens associated with conjunctivitis and corneal ulcers with special reference to S. pneumoniae. Methods: A descriptive cross-sectional study was carried out from January to April 2008 in which samples were collected from patients above one month old with suspected conjunctivitis or corneal ulcers seen in the out-patients department and wards of the National Eye Hospital, Colombo, Sri Lanka. Both eye swabs (n=322) and corneal buttons (n=31) were cultured. Isolated bacteriawere identified as far as possible and antibiotic sensitivity testing done. S. pneumoniae isolates were stored in sheep blood agar slants at -70 oC and serotyped. Results: There were 296 conjunctival swabs and 26 corneal swabs. From 296 conjunctival swabs 118 (39.8%) samples yielded no bacterial growth. There were 185 bacterial isolates from 159 significant positive samples. The most frequently isolated bacteria were coagulase negative Staphylococcus sp. (n=58: 31.4%), and second commonest was S. pneumoniae (n=33: 17.84%). From 57 samples from patients with corneal ulcers, 47 (82%) did not yield any bacterial growth. Sensitivity to chloramphenicol was high among Staphylococcus sp., S. pneumoniae, Haemophilus influenzae, Moraxella sp and coliforms. Among pneumococcal isolates serotyped, 19F was predominant. Conclusion: Coagulase negative staphylococci were predominantly isolated from eye swabs and corneal buttons, but the most significant frequent isolate was S. pneumoniae. Except Pseudomonas, >90% isolates were sensitive to chloramphenicol. The predominant pneumococcal serotype was 19F.