Listeria monocytogenes cross-contamination of cheese: risk throughout the food supply chain.

Listeria monocytogenes has been the most common microbial cause of cheese-related recalls in both the United States and Canada in recent years. Since L. monocytogenes is inactivated by pasteurization, the majority of these cases have been linked to environmental and cross-contamination of fresh-soft, soft-ripened, and semi-soft cheeses. Cross-contamination of foods with L. monocytogenes is a continuous risk throughout the food supply chain and presents unique challenges for subsequent illness and outbreak investigations. Reports on outbreaks of listeriosis attributed to cross-contamination downstream from primary processing help highlight the critical role of epidemiological investigation coupled with coordinated molecular subtyping and surveillance in the recognition and investigation of complex foodborne outbreaks. Despite their complexity, environmental sampling throughout the supply chain coupled with improved genotyping approaches and concomitant analysis of foodborne illness epidemiological exposure data are needed to help resolve these and similar cases more rapidly and with greater confidence.

[Mouse models of diabetic retinopathy: systematic review of the literature]. / Revue systématique de la littérature des modèles murins de rétinopathie diabétique.

INTRODUCTION: Diabetic retinopathy (DR) is a leading cause of vision loss worldwide. A variety of species of animals have been used to investigate the pathogenesis of DR. However, the mouse model of diabetic retinopathy, which is an attractive model due to the genetic modifications which can be carried out, remains underutilized. In order to explain this discrepancy, we performed a review of the literature concerning various mouse models of diabetic retinopathy so as to define their advantages and disadvantages. MATERIAL AND METHODS: We carried out a literature review using PubMed. We selected articles describing models of DR with pericyte loss, retinal capillary abnormalities and hyperglycemia. Articles not meeting these three criteria were excluded. RESULTS: Out of 25 articles, we found seven models of DR. For each of these models, we report the method of induction of DR and the electrophysiological and histopathological features. CONCLUSION: Models obtained through genetic manipulation appear the most interesting, since the diabetes and its complications present early without additional physiologic modifications. However, since these models differ frequently by sex, this is an important parameter that must be taken into account.

Ultra-wide-field autofluorescence imaging in non-traumatic rhegmatogenous retinal detachment.

PURPOSE: Rhegmatogenous retinal detachment (RRD) affects the function of the retina before and after surgical repair. We investigated ultra-wide-field autofluorescence (UAF) abnormalities in patients with acute RRD to improve our understanding of the functional changes in the retina before and after surgery. METHODS: In this retrospective study, we present the UAF imaging findings of 16 patients with acute, non-traumatic RRD. Imaging was obtained with the Optos 200 Tx (Optos) in 14 eyes preoperatively and in 12 eyes postoperatively. Twelve eyes had RRDs that involved the macula (group A), whereas four eyes had macula-sparing RRDs (group B). RESULTS: All patients (100%) with bullous retinal detachments demonstrated hypofluorescence over the area of retinal detachment. A hyperfluorescent leading edge (HLE) to the retinal detachment was observed preoperatively in 100% of eyes in group A and 75% of eyes in group B. Preoperative UAF through the fovea of group A eyes was normal (30%), hypofluorescent (50%) or hyperfluorescent (20%). In all patients with a HLE preoperatively, the HLE resolved by the 1-month postoperative visit. A residual line of demarcation remained in 8 of the 12 eyes (67%). In group A eyes, postoperative granular autofluorescent changes were present in four of the nine (44%) eyes, and were associated with worse preoperative (P=0.04) and postoperative (P=0.09) visual acuity. CONCLUSION: UAF imaging reveals abnormalities in RRDs that allow excellent demarcation of the extent of the retinal detachment and assist in preoperative characterization of the detachment and postoperative counselling.

Microbiological quality of raw milk used for small-scale artisan cheese production in Vermont: effect of farm characteristics and practices.

This study 1) evaluated the overall milk quality and prevalence of 4 target pathogens (Listeria monocytogenes, Staphylococcus aureus, Salmonella spp., and Escherichia coli O157:H7) in raw milk used for small-scale artisan cheesemaking and 2) examined specific farm characteristics and practices and their effect on bacterial and somatic cell counts (SCC). Raw milk samples were collected weekly from 21 artisan cheese operations (6 organic) in the state of Vermont that manufactured raw-milk cheese from cow (12), goat (5), or sheep (4) milk during the summer of 2008. Individual samples were examined for standard plate counts (SPC), coliform counts (CC), and SCC. Samples were also screened for target pathogens both quantitatively and qualitatively by direct plating and PCR. Overall, 86% of samples had SPC <10,000 cfu/mL, with 42% <1,000 cfu/mL. Additionally, 68% of samples tested were within pasteurized milk standards for coliform bacteria under the United States' Grade A Pasteurized Milk Ordinance at <10 cfu/mL. Log(10) SPC and CC did not differ significantly among species. Similarly, method of sample delivery (shipped or picked up), farm type (organic or conventional), and duration of milking (year-round or seasonal) did not have significant effects on farm aggregated mean log(10) SPC, CC, or SCC. Strong positive correlations were observed between herd size and mean log(10) SPC and between log(10) SPC and CC as well as SCC when data from all animal species were combined. Although SCC for cow milk were significantly lower than those for goat and sheep milk, 98, 71, and 92% of cow, sheep, and goat milk samples, respectively, were within the compliance limits of the United States' Grade A Pasteurized Milk Ordinance for SCC. Fourteen of the 21 farms (67%) were positive for Staph. aureus, detected in 38% of samples at an average level of 20 cfu/mL. Neither L. monocytogenes, E. coli O157:H7, or Salmonella spp. were detected or recovered from any of the 101 samples tested. Our results indicate that the majority of raw milk produced for small-scale artisan cheesemaking was of high microbiological quality with no detectable target pathogens despite the repeat sampling of farms. These data will help to inform risk assessments that evaluate the microbiological safety of artisan and farmstead cheeses, particularly those manufactured from raw milk.

Ablation of vitreous tissue with a high repetition rate erbium:YAG laser.

PURPOSE: To quantify erbium (Er):YAG laser ablation of vitreous in relation to different pulse repetition rates < or = 200 Hz, in order to examine the feasibility of laser for removal of vitreous gel (photovitrectomy) in clinically acceptable times. METHODS: Fresh porcine vitreous samples and saline controls were ablated in air with an Er:YAG laser connected to a sapphire fiber at pulse energies between 1.0 and 21.2 mJ and at pulse repetition rates between 10 and 200 Hz. Net ablation rates were determined by weight measurement. RESULTS: Reproducible and constant ablation rates were found for given laser parameters. Net ablation rates increased linearly with pulse repetition rate and nonlinearly with pulse energy. Expanded laser parameter domains permitted vitreous ablation rates as low as 1 microg/s to as high as 1031 microg/s. Ablation rates did not differ significantly between vitreous and saline. CONCLUSIONS: The study documents clinically useful vitreous ablation rates that scale linearly with high repetition rates of Er:YAG laser, and suggests directions for further development of laser technology for enhanced removal of vitreous and other tissues. However, nonlinear effects of pulse energy also exist, indicating need for careful examination of ablation characteristics in various instruments.

Evaluation of primary surgical procedures for retinal detachment with macular hole in highly myopic eyes: a comparison [corrected] of vitrectomy versus posterior episcleral buckling surgery.

PURPOSE: To evaluate postoperative outcomes between pars plana vitrectomy (PPV) and posterior episcleral buckle procedure (PEBP) in myopic eyes with retinal detachment (RD) and macular hole (MH). DESIGN: Retrospective nonrandomized comparative interventional trial. PARTICIPANTS AND INTERVENTION: The study included 30 phakic, highly myopic eyes (from 19-30 negative diopters) of 30 patients with an RD and MH. The patients were divided into two groups: They were assigned to PPV (15 eyes, group A) or to PEBP (15 eyes, group B). No significant (P > 0.01) differences in preoperative visual acuity (VA) between group A and group B eyes were found. Follow-up was 12 months. MAIN OUTCOME MEASURES: Anatomic attachment of the retina was determined, and VA was measured. RESULTS: Retinal reattachment was obtained on 11 of 15 (73.3%) eyes of group A and on 14 of 15 (93.3%) eyes of group B. In group A eyes the VA was substantially unmodified after surgical treatment, whereas in group B eyes the VA observed after surgical treatment increased significantly (P < 0.001) with respect to the preoperative values. CONCLUSIONS: PEBP resulted in better postoperative anatomic and functional results compared with PPV in eyes with extreme degrees of myopia, pronounced posterior staphyloma, and posterior vitreous schisis affected with RD caused by MH.

Central retinal vein occlusion in a patient with thrombotic thrombocytopenic purpura.

PURPOSE: To describe the occurrence of central retinal vein occlusion in a patient with thrombotic thrombocytopenic purpura. METHODS: Case report. RESULTS: A 52-year-old woman developed central retinal vein occlusion in the acute phase of thrombotic thrombocytopenic purpura, followed by iris neovascularization only 1 month after the onset of central retinal vein occlusion. Color Doppler imaging of the affected eye showed an increased resistive index of the central retinal artery and reduced blood flow velocity of the central retinal vein compared to the fellow eye. CONCLUSION: We describe a rare association between central retinal vein occlusion and thrombotic thrombocytopenic purpura with rapid evolution of iris neovascularization. Our case demonstrates that close ophthalmologic attention is important in thrombotic thrombocytopenic purpura.

Sclerosing inflammatory pseudotumor of the eye.

We report the clinical course and pathologic findings in a case of intraocular sclerosing inflammatory pseudotumor in a 21-year-old man. The patient initially had a unilateral right interstitial keratitis, scleritis, uveitis, ciliary body mass, and retinal detachment. Scleral and vitreous biopsy specimens revealed an inflammatory process. The eye was eventually enucleated despite therapy with high doses of prednisone and ciprofloxacin hydrochloride. Histologic examination of the globe showed nongranulomatous, acute (neutrophils) and chronic (lymphocytes and histiocytes) inflammation with proliferation of fibrous tissue within the vitreous cavity, uvea, sclera, and contiguous orbital fibroadipose tissue. The contralateral eye later developed a similar mass that resolved following aggressive and prolonged immunosuppressive therapy with retention of 20/16 visual acuity.

Maculopathies that resemble optic neuropathies.

This chapter outlines some diseases in which diagnosis of retinal pathology can prove difficult and often mislead one to think of optic nerve disease. Clinicians should consider these entities when atypical features or unexplained visual loss occurs. A careful medical history, review of systems, and the appropriate use of ancillary studies (as outlined) can provide insights helpful in making the correct diagnosis.

Elevation of vitreous leptin in diabetic retinopathy and retinal detachment.

PURPOSE: Leptin is a cytokine that regulates energy metabolism and is linked to diabetes mellitus through its metabolic actions. Leptin is angiogenic and promotes wound healing, and therefore this investigation was conducted to determine whether leptin is associated with neovascular and fibrotic complications of diabetes and other retinopathies. METHODS: Serum and vitreous samples were collected from patients classified by the presence and type of diabetic retinopathy or other ocular diseases. Leptin was measured in serum and vitreous by radioimmunoassay, and leptin and leptin receptor were localized in epiretinal membranes immunohistochemically. RESULTS: Leptin levels in serum and vitreous were higher in patients with diabetes than in those without, and vitreous leptin concentrations were especially elevated in patients with proliferative diabetic retinopathy or retinal detachment. Leptin and leptin receptor were detected in fibrovascular epiretinal membrane of patients with diabetes. CONCLUSIONS: Leptin in human vitreous is elevated in proliferative diabetic retinopathy, and retinal detachment and is present in fibrovascular epiretinal tissue. These data suggest an involvement of leptin in retinal disease.

Bacterial subretinal abscess: a case report and review of the literature.

PURPOSE: To report a case of Klebsiella subretinal abscess with a successful visual outcome with treatment and to review the literature pertaining to focal intraocular infection in bacterial endophthalmitis. METHODS: Clinical data including medical history, findings on physical examination, blood cultures, and an abdominal computed tomographic scan were collected in a 32-year-old man with Klebsiella sepsis, liver abscesses, and a focal subretinal abscess. Ocular data including visual acuity, fundus photographs, fluorescein angiography, and ultrasound were evaluated, as were results of culture and histopathologic studies. RESULTS: Despite immediate intervention, including vitreous tap and intravitreal antibiotics, the eye deteriorated, with enlargement of the abscess. A pars plana vitrectomy was performed in which the subretinal abscess material was removed after an extensive retinectomy of the involved area in association with an endophotocoagulative barrier and intravitreal amikacin without gas or oil tamponade. Culture confirmed Klebsiella subretinal infection. A retinal detachment occurred 1 month postoperatively and was successfully repaired. Visual acuity was 20/30 and has remained stable for 14 months. CONCLUSION: Klebsiella endophthalmitis with subretinal abscess formation is a rare but devastating ocular condition. In the present case, prompt intervention with extensive retinectomy, complete abscess excision, and intravitreal antibiotic therapy resulted in unprecedented visual recovery.

Intravitreal dexamethasone effect on intravitreal vancomycin elimination in endophthalmitis.

OBJECTIVE: To determine whether intravitreal dexamethasone administration can alter the elimination of intravitreal vancomycin hydrochloride in rabbit eyes with experimental Streptococcus pneumoniae endophthalmitis. METHODS: Albino rabbits were infected with an intravitreal inoculum of S pneumoniae (2 x 10(3) colony-forming units) and randomized after 24 hours to treatment with intravitreal vancomycin hydrochloride (1 mg), alone or in combination with intravitreal dexamethasone (400 microg). For comparison, uninfected eyes were similarly treated. All eyes were enucleated 24, 48, or 72 hours after treatment, and vitreous levels of vancomycin were quantitated using a fluorescence polarizing immunoassay. RESULTS: The half-life of intravitreal vancomycin in infected eyes was prolonged from 48 to 84 hours when eyes were treated with dexamethasone. Conversely, such treatment shortened the half-life in uninfected eyes from 56 to 42 hours. CONCLUSIONS: Intravitreal dexamethasone administration reduces the elimination of intravitreal vancomycin in rabbit eyes with pneumococcal endophthalmitis, whereas an opposite effect is noted in uninfected eyes. CLINICAL RELEVANCE: In patients with eyes having endophthalmitis caused by virulent organisms, the elimination of intravitreal vancomycin may be reduced when intraocular inflammation is minimized with corticosteroid therapy. This may enhance the efficacy of intravitreal vancomycin therapy in treating the infection.