Diagnosis Of Bacterial Keratitis Research Articles

Clinical comparative analysis of culture-proven bacterial keratitis according to prior topical steroid use: a retrospective study in a tertiary referral center of South Korea

This study analyzed the clinical characteristics of patients exposed to topical steroids before bacterial keratitis diagnosis (the prior topical steroid use, PS group), and compared these with those of the non-exposed group (the no prior topical steroid use, NPS group). We retrospectively analyzed 194 patients (PS, 34; NPS, 160) with culture-proven bacterial keratitis between 2007 and 2016. The microbiological profiles, epidemiology, predisposing factors, clinical characteristics, and treatment outcomes of PS and NPS were compared, and the risk factors for surgical intervention were evaluated. Pseudomonas spp. and Staphylococcus spp. were the most common isolates in PS and NPS, respectively, and no significant difference in the strain distribution between the two groups were observed. Significant differences were observed between PS and NPS for previous ocular surface disease (41.2%: 23.8%), initial BCVA < 0.1 (70.6%: 49.4%), epithelial defect size ≥ 5 mm2 (64.7%: 41.2%), epithelial healing time > 14 days (55.9%: 37.3%), and surgical intervention (23.5%: 8.8%). Prior topical steroid use, strong steroid use, and long-term steroid use groups were included in significant risk factors for surgical intervention. Previous exposure to topical steroids before the diagnosis of bacterial keratitis was associated with a worse initial clinical presentation and treatment outcomes. Additional multicenter studies should be conducted in the future.

Keratitis following leech therapy for periocular eczematous dermatitis: a case report

BackgroundThe medicinal leech therapy (MLT) is a kind of complementary treatment method used for various diseases. The leeches (Hirudo medicinalis) have been used for more than 2500 years by surgeons. The substances presenting in the saliva of leeches have anti-inflammatory, anticoagulant, platelet inhibitory, thrombin regulatory, analgesic, extracellular matrix degradative and antimicrobial effects. The method is cheap, easy to apply, effective and its mechanisms of action have been clarified for specific diseases. Infection particularly Aeromonas infection is the most common complication of MLT.Case presentationIn this case report, a keratitis case developing after leech therapy applied for the periocular and facial eczematous dermatitis lesions will be presented. The patient referred to our hospital with decreased vision, ocular pain, stinging, redness and lacrimation complaints. A large corneal epithelial defect with irregular margins, dying by fluorescein, involving more than inferior half of cornea and conjunctival hyperemia were seen in the right eye. No agent was determined in microbiological investigation, as the patient had used topical moxifloxacin eye drop which was commenced in another clinic before applying to us. The patient was treated with fortified vancomycin and ceftazidime, before using besifloxacin with the diagnosis of bacterial keratitis. Three weeks later epithelial defect improved completely leaving an opacity and neovascularization.ConclusionsMLT should be performed by certified physicians with sterile medicinal leeches and precautious antibiotics should be used before MLT for prevention against potential infections.

Bacterial keratitis: identifying the areas of clinical uncertainty.

Bacterial keratitis is a common corneal infection that is treated with topical antimicrobials. By the time of presentation there may already be severe visual loss from corneal ulceration and opacity, which may persist despite treatment. There are significant differences in the associated risk factors and the bacterial isolates between high income and low- or middle-income countries, so that general management guidelines may not be appropriate. Although the diagnosis of bacterial keratitis may seem intuitive there are multiple uncertainties about the criteria that are used, which impacts the interpretation of investigations and recruitment to clinical studies. Importantly, the concept that bacterial keratitis can only be confirmed by culture ignores the approximately 50% of cases clinically consistent with bacterial keratitis in which investigations are negative. The aetiology of these culture-negative cases is unknown. Currently, the estimation of bacterial susceptibility to antimicrobials is based on data from systemic administration and achievable serum or tissue concentrations, rather than relevant corneal concentrations and biological activity in the cornea. The provision to the clinician of minimum inhibitory concentrations of the antimicrobials for the isolated bacteria would be an important step forward. An increase in the prevalence of antimicrobial resistance is a concern, but the effect this has on disease outcomes is yet unclear. Virulence factors are not routinely assessed although they may affect the pathogenicity of bacteria within species and affect outcomes. New technologies have been developed to detect and kill bacteria, and their application to bacterial keratitis is discussed. In this review we present the multiple areas of clinical uncertainty that hamper research and the clinical management of bacterial keratitis, and we address some of the assumptions and dogma that have become established in the literature.

Frequency of Causative Factors and Microbial Etiology of the Keratitis

Objective: To determine the frequency of the causative factors and most common organisms of keratitis. Materials and methods: This descriptive cross- sectional study was conducted at the Ophthalmology department of Indus Medical College Tando Muhammad Khan. The study included both male and female patients diagnosed with microbial keratitis between the ages of 17 and 60 years. Slit lamp bio microscopy of the anterior segment was performed on all patients, and the corneal epithelial defect was quantified in millimeters using the slit lamp. Corneal scrapings were collected from the base of ulcer using a bent tip 26-gauge hypodermic needle under topical anaesthetic (Alcain), and the sample was immediately studied under an electron microscope, confirming the diagnosis of bacterial keratitis. Patients were then hospitalized, and at the conclusion of therapy, their healing was examined. The research proforma was used to gather all the data, and SPSS version 26 was applied for data analysis. Results: A total of 70 cases diagnosed with microbial keratitis were studied with an average age was 38.22+7.81 years and males were in majority 65.7%. A majority of the patients 55.7% were poor socioeconomically, followed by 32.9% had middle socioeconomic status and only 11.4% were rich socioeconomically. Contact lens and trauma were commonest factors as 28.6% and 24.3% respectively, followed by a history of steroid 11.4%, past ocular previous surgery 11.4%, ocular surface illness 14.3% cases, and others10.0%. Bacterial and fungus keratitis were commonest 55.7% and 27.1% respectively, followed by 12.9% viral keratitis, mixed microbial keratitis was 2.9% and only one case had Acanthamoeba keratitis. Conclusion: This study concludes that rural areas’ poor young males were highly affected by the microbial keratitis. Trauma and unhygienic lens wear were observed to be the prevalent causative factors, with highly prevalent bacterial and fungal microbial etiology. Keywords: factors, prevalence, microbes, keratitis

Polymicrobial Keratitis: Risk Factors, Clinical Characteristics, Bacterial Profile, and Antimicrobial Resistance.

To describe clinical characteristics, complications, and the most prevalent microorganisms causing polymicrobial keratitis and their antibiotic sensitivities. A cross-sectional study including a consecutive analysis of patient's records with a diagnosis of bacterial keratitis with a positive culture and antibiogram report were included. Patients were grouped into those having monomicrobial and polymicrobial infection. Features studied included demographic and clinical characteristics, risk factors, Gram stain, cultures, and antibiotic sensitivity. We included 656 patients; in 31.5% more than one microorganism was found. Seven hundred and twenty-three gram-positive bacteria were isolated, and 336 (46.5%) had polymicrobial keratitis. One hundred sixty-one gram-negative bacteria were isolated, and 99 (61.5%) from polymicrobial keratitis. Fourteen (0.60%) patients presented ring infiltrate, and 10 (71.42%) of those patients had polymicrobial keratitis (X2 10.654, P=0.001). Multivariate analysis showed that patients with history of contact lens use (odds ratio [OR] of 1.78, P=0.042), coexistent autoimmune disease (OR 4.64, P=0.03), irregular edges of the infiltrate (OR 2.06, P=0.005), and ring infiltrate (OR 6.034, P=0.005) have a higher risk for developing polymicrobial infection. In the polymicrobial group, gram-positive and gram-negative organisms showed a high sensitivity to Netilmicin. We found a high incidence of polymicrobial keratitis. Our results suggest that it should be suspected in patients with a history of contact lens use, coexistent autoimmune disease, infiltrates with indistinct edges, and ring infiltrates. Sensitivities to moxifloxacin are lower than those reported in previous studies, but sensitivity to Netilmicin is higher.

16S RNA PCR in the diagnosis of bacterial keratitis and endophthalmitis

AbstractPurpose Classical bacterial culture often fails to detect the infecting agent in bacterial keratitis and endophthalmitis. Our study was designed to evaluate the contribution of 16S RNA amplification using polymerase chain reaction (PCR) and nested PCR, when compared to culture, in the diagnosis of bacterial keratitis and endophthalmitis.Methods In this prospective study, we included 63 patients (24 bacterial keratitis and 39 endophthalmitis). For every patient, two samples were taken: one for bacterial culture, the other for PCR. PCR and nested PCR 16S rRNA were performed using universal primers (8/27‐1510 for PCR and 91E‐13BS for nested PCR) and the amplicons were thereafter sequenced.Results Culture offers a sensibility of 25%; associated to first PCR (8/27‐1510), this rate increase to 31,7%, and with nested PCR (91E‐13BS), we had 34,9% of identifications. We have to note that the rate of positive PCR were much better, but the sequencing rate was 59,5% only. For bacterial keratitis, culture was positive in 25% and PCR in 8%. For aqueous humor samples, culture was positive in 32%, PCR in 25% and nested PCR in 20,6%. Sequencing was possible in 76,5% for humor aqueous samples.. For vitreous samples, the culture alone was positive in 9%, PCR in 36,3%, and nested PCR in 36,3%.Conclusion 16S rRNA PCR is a rapid alternative to culture, sensitive and reproductible.. PCR associated to culture increases the number of positive samples. PCR was found necessary for the microbiological diagnosis in 10% of all cases (PCR+, cultures‐).

Bakterielle Keratitis – aktuelle Aspekte zur Diagnostik

Keratitis remains the third most common etiology for blindness worldwide. Whereas bacteria still predominate as causative organisms in temperate climates, fungal and mixed infections are more common in tropical and semitropical areas. In recent years, a shift in the causative organisms, as well as predisposing factors, has been reported. Risk factors that may have gained in importance, such as wearing contact lenses and corneal surgery, have been identified. Microorganisms, especially Pseudomonas spp. and mycobacteria have been frequently isolated in these patients. A changing pattern in microorganism infection has been observed that might be caused by inappropriate use of potent antimicrobial agents. Because of the sight threatening nature of bacterial keratitis, proper diagnosis and antibiotic selection are required. Management should be guided by the appropriate diagnosis, severity of clinical symptoms and underlying risk factors. Molecular techniques, such as polymerase chain reaction, have increased our diagnostic options, even when they cannot replace established procedures. This article reviews the current data and procedures available for the diagnosis of bacterial keratitis.