Study of the genetic diversity of Moraxella spp. isolates obtained from corneal abscesses / Estudio de la diversidad genética de aislamientos de Moraxella spp. a partir de abscesos corneales

Abstract This is the first study of the genetic diversity of Moraxella spp. Isolates were detected in an Eye Hospital in the City of Buenos Aires. Due to the high frequency of Moraxella spp. observed in corneal abscesses, we decided to validate their identification at the species level, determine their drug susceptibility and perform molecular subtyping. Seventeen (17) isolates obtained from corneal abscesses were evaluated. The identification was carried out using a combination of biochemical tests and MALDI-TOF mass spectrometry. Of these isolates, 88.2% were identified as Moraxella lacunata, and 11.8% as Moraxella nonliquefaciens. Molecular subtyping was performed using the pulsed-field gel electrophoresis (PFGE) technique. All isolates were typable and thirteen digestion patterns were identified. Based on the obtained results, the PFGE technique using the SmaI enzyme can be used for epidemiological studies of strains of these species.

Resumen En este trabajo se presenta el primer estudio de diversidad genética de aislamientos de Moraxella spp. detectados en un hospital de oftalmología de la Ciudad Autónoma de Buenos Aires. Debido a la observación de una elevada frecuencia de Moraxella spp. en abscesos corneales, se decidió confirmar su identificación a nivel de especie, conocer su sensibilidad y realizar la subtipificación molecular. Se analizaron 17 aislamientos provenientes de abscesos corneales. La identificación se realizó mediante una combinación de pruebas bioquímicas y espectrometría de masas, MALDI-TOF MS. El 88,2% fueron identificados como Moraxella lacunata y el 11,8% como Moraxella nonliquefaciens. La subtipificación molecular se realizó por la técnica de electroforesis en gel de campo pulsado (PFGE). Todos los aislamientos fueron tipificables y se identificaron 13 patrones de digestión. Nuestros resultados muestran que la técnica de PFGE con la enzima SmaI es útil para hacer estudios epidemiológicos en cepas de estas especies.

Study of the genetic diversity of Moraxella spp. isolates obtained from corneal abscesses.

This is the first study of the genetic diversity of Moraxella spp. Isolates were detected in an Eye Hospital in the City of Buenos Aires. Due to the high frequency of Moraxella spp. observed in corneal abscesses, we decided to validate their identification at the species level, determine their drug susceptibility and perform molecular subtyping. Seventeen (17) isolates obtained from corneal abscesses were evaluated. The identification was carried out using a combination of biochemical tests and MALDI-TOF mass spectrometry. Of these isolates, 88.2% were identified as Moraxella lacunata, and 11.8% as Moraxella nonliquefaciens. Molecular subtyping was performed using the pulsed-field gel electrophoresis (PFGE) technique. All isolates were typable and thirteen digestion patterns were identified. Based on the obtained results, the PFGE technique using the SmaI enzyme can be used for epidemiological studies of strains of these species.

Dolosigranulum pigrum en absceso corneal / Dolosigranulum pigrum in corneal abscess

Resumen Dolosigranulum pigrum es un coco gram positivo, anaerobio facultativo, que forma parte de la microbiota oral y del tracto respiratorio superior. Aunque los reportes de infecciones por este microorganismo son escasos, se lo ha asociado a un amplio espectro de enfermedades infecciosas. Se describe el caso de un hombre adulto con un absceso corneal del que se aisló D. pigrum. El microorganismo fue identificado por espectrometría de masas (MALDI-TOF MS) y secuenciación del gen 16S ARNr. A su vez, se logró la identificación presuntiva mediante pruebas fenotípicas claves, como la disposición en racimos en la coloración de Gram, la prueba negativa de la catalasa, la producción de pirrolidonil arilamidasa y leucina aminopeptidasa, el crecimiento en NaCl al 6,5% y la hidrólisis de esculina. Los datos de la literatura y el presente caso respaldan la asociación del microorganismo con infecciones oculares, a menudo de curso destructivo, principalmente en pacientes de edad avanzada.

Abstract Dolosigranulum pigrum is a gram-positive, facultatively anaerobic coccus, which is part of the oral and upper respiratory tract microbiota. Although reports of infections by this microorganism are scarce, it has been associated with a wide spectrum of infectious diseases. The case of an elderly man with a lower corneal abscess, in which Dolosigranulum pigrum was isolated, is described. The microorganism was identified by mass spectrometry (MALDI-TOF MS) and by the sequencingof the 16S rRNAgene. Furthermore, the presumptive identification of the causative agent was achieved by using key phenotypic tests such as the cluster arrangement in Gram stain, the negative catalase test, the production of pyrrolidonyl arylamidase and leucine aminopeptidase activity, the growth in 6.5% NaCl and esculin hydrolysis. The data from the literature (and the present case) support the association of the microorganism with ocular infections, which often take a destructive course, mainly in elderly patients.

Moraxella nonliquefaciens superinfecting herpes simplex keratitis.

INTRODUCTION: Moraxella nonliquefaciens (M. nonliquefaciens) is a low pathogenicity microorganism, which rarely causes ocular infections, unless there is a predisposing factor. The main clinical manifestation of M. nonliquefaciens ocular infections is endophthalmitis and only five cases of corneal infection have been reported. This work shows an update in M. nonliquefaciens corneal infections, and the first reported case of keratitis due to M. nonliquefaciens superinfecting herpes simplex infection. CASE REPORT: A 84-year old woman with worsening of her herpes simplex keratitis, diagnosed, and treated 2 days before. The slit lamp showed deep paracentral infiltrate and hypopyon. A corneal sample was collected for culture prior to initiation of empiric antibiotic therapy with vancomycin and ceftazidime fortified, oral acyclovir, and cyclopentolate. The strain was identified as M. nonliquefaciens and topical antibiotic therapy was adjusted to ciprofloxacin and ceftazidime. After 2 weeks, the epithelial defect and the infiltrate were resolved and prednisolone was added to the regimen. As the corneal oedema and neovascularization decreased, acyclovir, and prednisolone were slowly tapered. About 4 months later, the visual outcome was 20/50 and the ophthalmic examination showed a clear cornea with a paracentral leucoma. CONCLUSION: Keratitis due to M. nonliquefaciens is rare and should be suspected in patients with local predisposing factors such as corneal damage or previous corneal infection. Prompt and appropriate combined treatment for the predisposing lesions and the keratitis may improve the prognosis and avoid a more aggressive approach.

[Dolosigranulum pigrum in corneal abscess]. / Dolosigranulum pigrum en absceso corneal.

Dolosigranulum pigrum is a gram-positive, facultatively anaerobic coccus, which is part of the oral and upper respiratory tract microbiota. Although reports of infections by this microorganism are scarce, it has been associated with a wide spectrum of infectious diseases. The case of an elderly man with a lower corneal abscess, in which Dolosigranulum pigrum was isolated, is described. The microorganism was identified by mass spectrometry (MALDI-TOF MS) and by the sequencing of the 16S rRNA gene. Furthermore, the presumptive identification of the causative agent was achieved by using key phenotypic tests such as the cluster arrangement in Gram stain, the negative catalase test, the production of pyrrolidonyl arylamidase and leucine aminopeptidase activity, the growth in 6.5% NaCl and esculin hydrolysis. The data from the literature (and the present case) support the association of the microorganism with ocular infections, which often take a destructive course, mainly in elderly patients.

Case series of scleral patch grafts during COVID-19 pandemic.

Scleral graft is done for clinical conditions as scleral melt post pterygium surgery, immune or infection related scleral melt, for covering the tubes of Ahmed glaucoma valve implant, for covering the orbital implants post enucleation, etc. A review of literature revealed the use of sclera for corneal perforations in the past, but became obsolete after the cornea being used for patch grafts. Now in this COVID-19 time, due to scarcity of corneal tissue, this technique of scleral patch grafts can be considered as an alternative to corneal patch grafts, which serves well the tectonic/therapeutic purpose and helps salvage the eye.

Role of intrastromal vancomycin in recalcitrant corneal abscess after phacoemulsification.

Side port infection and corneal abscess after cataract surgery can produce devastating outcomes. Topical antibacterial drugs are the mainstay in management of these cases. Although intrastromal antifungal agents are an established modality for fungal keratitis, such use of antibacterial agents is rarely reported due to better pharmacokinetic profile of antibacterial agents.We report a case of methicillin-resistant Staphylococcus aureus corneal abscess following phacoemulsification that responded to intrastromal vancomycin injection in addition to conventional therapy.This case of postphacoemulsification corneal abscess highlights the importance of postoperative hygiene practices, use of anterior segment optical coherence tomography for monitoring these patients and use of intrastromal vancomycin as an adjunct to topical and systemic therapy.

Case Report: Successful Management of Refractory Keratomycosis in an Alpaca Using Penetrating Keratoplasty and Combination Antifungal Therapy (Caspofungin 0.5% and Terbinafine 1%).

Fungal keratitis is a common disease in certain parts of the world and affects several species, including equids, camelids, and homo sapiens, leading to blindness or loss of the eye if the infection is not adequately controlled. Reports of clinical use of antifungals caspofungin and terbinafine are limited across both veterinary and human medical literature. The alpaca presented in this case demonstrates that deep keratomycosis can be caused by Scopulariopsis brevicaulis and Fusarium verticillioides, two previously unreported fungi to cause keratomycosis in camelids. This report demonstrates successful management with a combination of surgery and topical ophthalmic treatment with caspofungin 0.5% solution and terbinafine 1% dermatologic cream, after initially failing treatment with topical voriconazole 1% solution. Combination therapy appears more effective than monotherapy with some fungal organisms, and synergy between antifungal agents is thought to play a role in the success of combination therapy. Surgery to remove the bulk of the fungal infection is especially helpful in cases that fail initial medical therapy.

Challenges in the diagnosis of microbial keratitis: A detailed review with update and general guidelines.

The incidence of microbial keratitis (MK) is variable worldwide with an estimated 1.5-2 million cases of corneal ulcers in developing countries. The complications of MK can be severe and vision threatening. Therefore, proper diagnosis of the causative organism is essential for early successful treatment. Accurate sampling of microbiological specimens in MK is an important step in identifying the infective organism. Corneal scrapping, tear samples and corneal biopsy are examples of specimens obtained for the investigative procedures in MK. Ophthalmologists especially in an emergency room setting should be aware of the proper sampling techniques based on their microbiology-related basic information for each category of MK. This review article briefly describes the clinical presentation and defines in details the best updated diagnostic methods used in different types of MK. It can be used as a guide for ophthalmology trainees and general ophthalmologists who may be handling such cases at initial presentation.

[Diagnostic and therapeutic contribution of microbiological analysis in severe microbial keratitis at Reims University Hospital between 2012 and 2014]. / Apport diagnostique et thérapeutique des prélèvements microbiologiques des abcès de cornées avec critères de gravité au CHU de Reims entre 2012 et 2014.

PURPOSE: To investigate the contribution of microbial analysis in the diagnosis and management of severe microbial keratitis. MATERIAL AND METHOD: This is a monocentric retrospective study at the University Hospital of Reims from January 2012 to December 2014. Corneal scrapings with infectious keratitis were subjected to routine bacterial and fungal culture. PCR was also performed to detect various viral DNA (VZV, CMV, EBV, HSV 1 & 2, adenovirus) and Acanthamoeba sp. DNA. All contact lens cases were analyzed if available. RESULTS: One hundred and six patients were hospitalized, including 30 contact lens wearers (28.3%). Sixty-four bacterial cultures were positive (68%). Twenty-five different bacterial species were identified with a majority of gram-positive bacteria (67.92%). Among contact lens wearers, the initial VA was better than non-wearers (P=0.0004) and 37% of bacteria identified (a plurality) were gram positive. Of 11 contact lens case analyzed, in only one case (3.3%) did the result correlate with the corneal culture. Only 9 samples from the 323 viral DNA extractions and real time PCR were positive (2.8%); 7 were HSV1. No prior antiviral therapy had been started. Fungal culture was positive in 2 of the 97 corneal samples taken and 63.6% of the contact lens cases (7/11 cases). Only one of the 40 Acanthamoeba sp. PCR's was positive. CONCLUSION: The systematic performance of microbiological investigations is a good diagnostic approach given the polymorphism of clinical presentations of corneal ulcers, which can sometimes be extremely misleading. Culture of contact lens cases appears ineffective for the detection and determination of the causative microorganism. The high incidence of Staphylococcus in bacterial keratitis and the prevalence of infections with gram-positive bacteria in contact lens wearers were noted.

[Non-traumatic corneal perforations: Therapeutic modalities]. / Perforations cornéennes non traumatiques : modalités thérapeutiques.

INTRODUCTION: The treatment of non-traumatic perforations of the cornea is a real challenge for the choice of surgical technique as well as for management of the causal pathology. The goal of our study is to determine the anatomical and functional results of the management of non-traumatic perforation of the cornea in the absence of ready access to a corneal graft. MATERIALS AND METHODS: This is a retrospective, non-comparative monocentric study of 23 consecutive cases diagnosed and treated between January 2011 and January 2013. We included 23 eyes with non-traumatic corneal perforation. Various surgical techniques were used depending on the size and location of the corneal perforation. RESULTS: The predominant etiology of the corneal perforations in our series was corneal abscess, found in 30.4% of cases (7 eyes). A conjunctival flap was performed in 43.5% of cases (10 eyes) followed by tarsorrhaphy in 21.7% of cases (5 eyes), autologous corneal patch in 17.4% of cases (4 eyes), amniotic membrane in 13% of cases (3 eyes) and finally cyanoacrylate glue in one case. Mean follow-up was 12.4 ± 2.1 months. Anatomical closure of the corneal perforation was achieved in 91.3% of cases (21 eyes), while the final visual acuity was not improved due to secondary opacities. DISCUSSION: The choice of surgical technique depends on the size of the corneal perforation, its location, its etiology and the resources available for emergencies. When amniotic membrane and corneal donor tissue are unavailable, conjunctival flap is an easy and effective technique, which is a good alternative to close corneal perforations less than 3mm. It improves ocular surface quality and prepares the eye for later penetrating keratoplasty. CONCLUSION: Conjunctival flap is a good technique that is still relevant today, especially in the absence of corneal donor tissue or amniotic membrane. The anatomical success rate is very satisfactory, but sometimes several interventions are needed to improve the visual prognosis.

Femtosecond Laser-Assisted Intra-Corneal Drug Delivery.

PURPOSE: To present a case of fungal keratitis that was successfully treated with direct intrastromal medication delivery through a corneal incision created with the femtosecond laser. METHODS: A 71-year-old female patient with recurrent episodes of an unresponsive, deep stromal keratitis for six months' duration, resistant to various therapeutic approaches, was referred to our institute. The 150 kHz Intralase iFS laser (Abbott Medical Optics Inc., Santa Ana, CA) was used to create a corneal pocket in an attempt to permit drug delivery directly into the corneal abscess. RESULTS: Five days after the intrastromal injections, the clinical condition was improved. Two years after the procedure, the cornea is stable and free of any clinical signs or symptoms of recurrence. CONCLUSIONS: In this case report, an alternative application of femtosecond laser technology is presented, performing intrastromal drug delivery through a corneal incision for the treatment of fungal keratitis.

Keratomycosis complicating pterygium excision.

The authors describe a case of keratomycosis that appeared after the exeresis of a pterygium. A 48-year-old patient had been referred with a red right eye associated with an abscess of the cornea along the ablation zone of the pterygium. The surgery had been performed a month beforehand. The abscess was 6 mm high and 4 mm wide. The authors instigated a treatment that included amphotericin B (0.25%) after noticing a clinical aspect evoking a fungal keratitis and finding several septate filaments on direct examination. On day 10, a Fusarium dimerum was isolated on Sabouraud agar. After 15 days of treatment, the result was favorable and the size of the ulceration as well as the size of the abscess had progressively decreased. The antifungal treatment was definitively stopped at 14 weeks. Infectious-related complications of the pterygium surgery are rare and are essentially caused by bacterial agents. Secondary infections by fungus are rare. There have been two previous cases reported: one that appeared 15 years after radiotherapy and another that appeared at 3 weeks post surgery, consecutive to the use of mitomycin C. To the authors' knowledge, this is the first case of a keratomycosis due to F. dimerum reported that complicated the exeresis of a pterygium without the use of an adjuvant antihealing treatment. Pterygium surgery is a common procedure; nevertheless, ophthalmologists need to be aware of the existence of potential infectious complications.