Statistical Analysis with Missing Data

INTRODUCTION 149 TAXONOMY 149 Historical Features 149 Current Taxonomic Status 149 Delineation of Species 149 Species of Clinical Importance 150 LABORATORY IDENTIFICATION 150 Isolation from Clinical Specimens 150 Morphological, Cultural, and Metabolic Characteristics 151 Species Identification 151 NOSOCOMIAL INFECTIONS CAUSED BY ACINETOBACTER SPP. 152 Overview 152 Respiratory Infection 152 Bacteremia 153 Meningitis 153 Urinary Tract Infection 154 Other Miscellaneous Infections 154 PATHOGENESIS OF ACINETOBACTER INFECTIONS 154 Predisposing Factors 154 Virulence of Acinetobacter spp. 154 EPIDEMIOLOGY 155 Human Carriage 155 Persistence in the Hospital Environment 155 TYPING SYSTEMS 156 Biotyping 156 Antibiograms 156 Serotyping 156 Phage Typing 157 Bacteriocin Typing 157 Protein Profiles 157 Multilocus Enzyme Electrophoretic Typing 157 Plasmid Profiles 157 Analysis by Pulsed-Field Gel Electrophoresis 157 Ribotyping 157 PCR-Based Methods 158 CLINICAL ANTIBIOTIC RESISTANCE 158 BIOCHEMICAL AND GENETIC MECHANISMS OF ANTIBIOTIC RESISTANCE 158 Genetics of Resistance 158 b-Lactams 159 Aminoglycosides 159 Quinolones 160 Other Antibiotics 160 THERAPY OF ACINETOBACTER INFECTIONS 160 CONCLUSIONS 160 ACKNOWLEDGMENTS 161 REFERENCES 161

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Acinetobacter spp. as nosocomial pathogens: microbiological, clinical, and epidemiological features.

Background Ocular trauma or disease may lead to severe corneal opacification and, consequently, severe loss of vision as a result of complete loss of corneal epithelial stem cells. Transplantation of autologous corneal stem-cell sources is an alternative to allograft transplantation and does not require immunosuppression, but it is not possible in many cases in which bilateral disease produces total corneal stem-cell deficiency in both eyes. We studied the use of autologous oral mucosal epithelial cells as a source of cells for the reconstruction of the corneal surface. Methods We harvested 3-by-3-mm specimens of oral mucosal tissue from four patients with bilateral total corneal stem-cell deficiencies. Tissue-engineered epithelial-cell sheets were fabricated ex vivo by culturing harvested cells for two weeks on temperature-responsive cell-culture surfaces with 3T3 feeder cells that had been treated with mitomycin C. After conjunctival fibrovascular tissue had been surgically removed from the ocular surfa...

https://www.nejm.org/doi/pdf/10.1056/NEJMoa040455

Corneal reconstruction with tissue-engineered cell sheets composed of autologous oral mucosal epithelium.

Herpes simplex virus (HSV) infections of humans have been documented since the advent of writing. The spectrum of disease was expanded to include primary and recurrent infections of mucous membranes (gingivostomatitis, herpes labialis, and genital HSV infections), keratoconjunctivitis, neonatal HSV infection, visceral HSV infections of the immunocompromised host, HSV encephalitis, Kaposi's varicella-like eruption, and an association with erythema multiforme. Cumulative experience suggests that factors associated with pregnancy may place both the mother and fetus at increased risk for severe infection, possibly because of altered cell-mediated immunity. The major risk to the fetus is with primary or initial genital HSV infection of the mother. PCR evaluation of cerebrospinal fluid can be utilized to monitor therapeutic outcome in patients with herpes simplex encephalitis. The use of HSV for gene therapy heralds a new era of herpes biology, the conversion of a hazardous foe into a user-friendly surgical tool. Asymptomatic shedding of virus can continue despite clinically effective suppression with acyclovir, so the possibility of person-to-person transmission persists. Newborns with HSV infections can be classified as having disease that is localized to the skin, eyes, and mouth; affects the central nervous system (CNS); or is disseminated. Drug resistance was considered rare and resistant isolates were thought to be less pathogenic until a series of acyclovir-resistant HSV isolates from patients with AIDS were characterized. The risk of nephrotoxicity can be minimized by administering acyclovir by slow infusion and ensuring adequate hydration.

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Herpes Simplex Viruses

Human corneal thickness and its impact on intraocular pressure measures: a review and meta-analysis approach.

Purpose To describe the incidence and prevalence of glaucoma in a patient population with severe ocular surface disease (OSD). Methods A retrospective case series was compiled from all charts of patients in the Cincinnati Eye Institute/University of Cincinnati and University of Minnesota population with a diagnosis of severe OSD from 1991 to 2003. The incidence and prevalence of glaucoma in the overall patient population were identified, and stratified into disease subgroups. Results Of the 108 eyes evaluated in this study, 71 were diagnosed with glaucoma. The overall prevalence of glaucoma in patients with severe OSD is 65.7%, with a range from 42.9% to 88.4%. Analysis by subgroup shows the highest percentage of patients with concurrent glaucoma fall into the categories of aniridia and chemical injury, and the lowest was noted in those patients with autoimmune or iatrogenic OSD. Overall, the incidence of glaucoma was 20.4%, with a range of 13.6% to 60%. Conclusions Compared with previous studies, our results show a significantly higher prevalence of glaucoma in patients with severe OSD. This information warrants increased attention to treatment and management of OSD and concurrent glaucoma.

Incidence and prevalence of glaucoma in severe ocular surface disease.

Although little has been written about iatrogenic limbal stem cell deficiency, patients with this disorder are probably more common than the literature might suggest. It is important to recognize this disorder as a limbal deficiency, since standard medical therapies will not address its etiology. The sequelae of this condition include stromal scarring and significant loss of vision. Fortunately, phacoemulsification has replaced ECCE and ICCE as the procedure of choice for cataract extraction in many parts of the world. Because of its shorter, and often temporally placed, incision, phacoemulsification is probably less likely to lead to iatrogenic limbal stem cell deficiency. Hopefully we will be witnessing less iatrogenic limbal stem cell deficiency in the future.

Iatrogenic limbal stem cell deficiency.

Intraocular Lens Implantation in Patients With Juvenile Rheumatoid Arthritis

Purpose To describe the systemic immunosuppression protocol used at the Cincinnati Eye Institute and University of Cincinnati, and to evaluate the success, tolerability, and side effects of systemic immunosuppression in patients undergoing ocular surface stem cell transplantation (OSST). Methods Retrospective study of all patients who had OSST from 1997 to 2007 and received follow-up for systemic immunosuppression at the Cincinnati Eye Institute. Patients were analyzed for demographics, systemic immunosuppression exposure, ocular surface stability, efficacy, and toxicity variables. Results A total of 225 eyes from 136 patients with a mean age of 43.6 years (range, 8.9-80.6 years) underwent OSST with systemic immunosuppression. The most common systemic immunosuppression regimen consisted of tacrolimus, mycophenolate mofetil, and a short course (1-3 months) of prednisone (102/136 patients, 75%). Prophylactic valganciclovir and trimethoprim/sulfamethoxazole (dapsone if sulfa allergy was present) were also used. Mean duration of immunosuppression was 42.1 months (range, 3.6-128 months) and mean follow-up time after OSST was 53.9 months (range, 3.6-147.3 months). At the patients' final follow-up visit, 105/136 patients (77.2%) had a stable ocular surface. There were 3 severe adverse events in 2 patients (1.5%) and 21 minor adverse events in 19 patients (14.0%). Of the 21 patients with adverse events, 10 (47.6%) had systemic comorbidities at initial presentation. Conclusions The prevention of graft rejection with the use of systemic immunosuppression after OSST is crucial and should be approached with the same rigor as in solid organ transplantation. With appropriate long-term monitoring by the cornea specialist and transplant physician, the risk of irreversible toxicity at current dosages of systemic immunosuppression in this population is minimal.

Systemic immunosuppression in ocular surface stem cell transplantation: results of a 10-year experience

Laser in situ keratomileusis (LASIK) is the most commonly performed refractive surgical procedure for the correction of ametropia. The advantages of LASIK include rapid visual rehabilitation, decreased stromal scarring, less irregular astigmatism, minimal regression, less postoperative pain, and the ability to treat a greater range of refractive disorders. Unlike surface-ablation procedures, LASIK preserves the integrity of Bowman’s membrane and the overlying epithelium, thus decreasing the risk for microbial keratitis. However, microbial keratitis following LASIK has become an increasingly recognized, sight-threatening complication of refractive surgery. The incidence of infectious keratitis following LASIK is difficult to estimate and can vary widely depending on the source of the information. One large retrospective study investigating the complications associated with LASIK found an incidence of 2 infections in 1062 eyes; a similar study found an incidence of 1 infection in 1019 eyes. A more recent case series of LASIK-associated infections encountered at a single institution reports an estimated incidence between 1:1000 and 1:5000. Based on a comprehensive review and analysis of the literature on infections following LASIK, Chang et al. state that the incidence of infection after LASIK can vary widely (0% to 1.5%). In a survey by the American Society of Cataract and Refractive Surgery (ASCRS), the incidence reported by LASIK surgeons who had experienced an infectious keratitis was 1 in 2919 cases performed during the year 2001. In this study of 116 cases, 76 presented the first week after surgery, 7 during the second week, 17 between the second week and the fourth week, and 16 after 1 month. The most common organisms cultured were atypical mycobacteria (33 of 116 cases, 28%) and staphylococci (23 of 116 cases, 20%) species. In 47 of the 116 cases, infectious keratitis was

Edward J. Holland

Papers

Incidence and prevalence of glaucoma in severe ocular surface disease.

Iatrogenic limbal stem cell deficiency.

Intraocular Lens Implantation in Patients With Juvenile Rheumatoid Arthritis

Systemic immunosuppression in ocular surface stem cell transplantation: results of a 10-year experience

ASCRS White Paper: Management of infectious keratitis following laser in situ keratomileusis.