Development of Genome-Driven, Lifestyle-Informed Markers for Identification of the Cereal-Infecting Pathogens Xanthomonas translucens Pathovars undulosa and translucens

Bacterial leaf streak, bacterial blight, and black chaff caused by Xanthomonas translucens pathovars are major diseases affecting small grains. Xanthomonas translucens pv. translucens and X. translucens pv. undulosa are seedborne pathogens that cause similar symptoms on barley, but only X. translucens pv. undulosa causes bacterial leaf streak of wheat. Recent outbreaks of X. translucens have been a concern for wheat and barley growers in the Northern Great Plains; however, there are limited diagnostic tools for pathovar differentiation. We developed a multiplex PCR based on whole-genome differences to distinguish X. translucens pv. translucens and X. translucens pv. undulosa. We validated the primers across different Xanthomonas and non-Xanthomonas strains. To our knowledge, this is the first multiplex PCR to distinguish X. translucens pv. translucens and X. translucens pv. undulosa. These molecular tools will support disease management strategies enabling detection and pathovar incidence analysis of X. translucens. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

First Report of Bacterial Leaf Streak of Barley (Hordeum vulgare) Caused by Xanthomonas translucens pv. translucens in British Columbia, Canada

Bacterial leaf streak (BLS) of barley is caused by the Gram-negative bacterial pathogen Xanthomonas translucens (Sapkota et al. 2020). In 2021, we observed multiple hill plots with BLS symptomatic plants in a barley stripe rust nursery in Vancouver, BC, Canada. We collected 29 leaf samples showing typical BLS symptoms (e.g. necrotic lesions; Fig. S1) and stored at 4 oC until bacterial isolation. Samples were surface-sterilized in 10% NaOCl for 20 sec and rinsed twice. About 1 cm2 of leaf tissue containing BLS characteristic lesions was macerated in 200 μL sterile H2O on a petri dish, incubated for 15 min, and 10 μl of the homogenates was streaked onto Wilbrink's - Boric Acid - Cephalexin (WBC) agar medium. Plates were incubated at 28-30 oC for 48 hrs. Four single colonies were obtained: BC10-1-2a (USask BC10-2a), BC10-1-2b (USask BC10-2b), UBC026 and UBC028. Colonies were grown in WBC broth and gDNA was extracted using E.Z.N.A. Bacterial DNA Kit (Omega Bio-Tek) or DNeasy Plant Pro Kit® (Qiagen) following manufacturer protocols. Genus-level identification was achieved using 16S rRNA sequencing with 27F/1492R primers (Lane 1991) of UBC026 (1,399 bp; NCBI # OP327375) and UBC028 (1,415 bp; NCBI #OP327376). Complete 16S rRNA sequences (1,533bp) of BC10-2a and BC10-2b (1,533 bp) were extracted from the draft whole-genome sequences (WGS) generated in this study. The 16S rRNA sequence homology values of 99.0-100% were recorded between the 4 strains. BLAST analyses of the 16S rRNA sequences to GenBank entries exhibited 99.5-100% similarity values (100% coverage) with the pathotype strains of Xtt DSM 18974T (LT604072) and X. translucens pv. undulosa (Xtu) CFBP 2055 (CP074361). Whole genomes of BC10-2a (JANUQY01) and BC10-2b (JANUQZ01) were sequenced (150-bp; reads 33.1 million; mean coverage 2125x) using NovaSeq Illumina, assembled (Unicycler v0.4.8; Wick et al. 2017) and analyzed to identify the strains to the species-level (Tambong et al. 2021). WGS of strains USask BC10-2a and USask BC10-2b exhibited genome-based DNA-DNA hybridization (dDDH; Meier-Kolthoff et al. 2013) and BLAST-based average nucleotide identity (ANIb; Richter et al. 2015) of 100%. The two strains also showed dDDH and ANIb of 90.4% (species-leel cut-off of 70%) and 98.780% and 98.80% (cut-off of 96%), respectively, with Xtt DSM 18974T (LT604072). In contrast, the WGS of BC10-2a and BC10-2b exhibited only 78.2% dDDH homology values with Xtu CFBP 2055T, suggesting that the strains are genetically more similar to Xtt. The assignment of these strains to Xtt is corroborated by phylogenomic analysis (Fig. S2; Meier-Kolthoff and Göker 2019) that showed the two strains clustering together (100% bootstrap) with the type strain DSM 18974T. These data suggest that these strains are taxonomically members of Xtt. Identification was also confirmed to the genus-level by LAMP assay using published X. translucens primers (Langlois et al. 2017). Pathovar-level identification was confirmed using a cbsA and S8.pep multiplex PCR diagnostic assay (Roman-Reyna et al. 2022). Koch's postulates were verified by greenhouse inoculation via leaf infiltration of UBC026 and UBC028 on 21-day old barley plants (line HB522) using an inoculum of 108 CFU ml-1 followed by re-isolation of the bacteria on WBC. The inoculated plants showed typical BLS symptoms similar to those observed in the field (Fig. S1). Water-inoculated plants had no symptoms. To our knowledge, this is the first published report of BLS of barley in British Columbia.

First report of Fusarium graminearum causing Fusarium Head Blight (FHB) of wheat and barley in Lower Mainland of British Columbia, Canada

Fusarium head blight (FHB), predominantly caused by Fusarium graminearum is one of the most economically important fungal diseases of small-grain cereals. Since the early 1990s, FHB has been a devastating wheat disease in parts of Canada and the United States, causing significant economic impacts on the cereal grain industry through reduced seed quality and yield, and grain contamination with fungal toxins (Brar et al. 2019). Spikes of wheat and barley with bleached spikelets and pinkish coloration were observed with low incidence and high severity in August 2021 field stripe rust nursery at UBC Totem Plant Science Farm in Vancouver, Canada (Supplementary File 1). FHB-like Symptomatic spikes were collected during the growing season. The Fusarium damaged kernels (FDK) were surface-sterilized with 1% sodium hypochlorite (NaOCl) for 1.5 min, rinsed three times in distilled water and dried using sterile filter paper discs in Biological Safety Cabinet. The kernels were placed on Petri dishes containing three layers of moist blotter papers and incubated in the dark at 22-25°C for 24 hours. The Petri dishes were transferred into a -20°C freezer for 24 hours, followed by five days of incubation at 22-25°C under fluorescent light, during which distilled water was added onto blotter papers every day to maintain moisture. After incubation, mycelium growing on kernels was transferred to potato dextrose agar (PDA) media and subcultured based on the colony and conidial morphology of F. graminearum (Leslie and Summerell 2006). The colonies selected grew white mycelia with a pink pigment at the bottom. Macroconidia with five to six septate were produced after seven days and microconidia were absent. Seven isolates derived from different wheat samples were derived from single conidia and identified based on amplicon sequencing using a MinION Flongle flow cell described by Boutigny et al. (2019). Reads which passed the integrated MinKNOW quality control step were mapped to the Partial translation elongation factor 1- α (EF1a) gene, using primers EF1-F2 (5'TCATC GGCCACGTCGACTCT3') and EF1-R3 (5'TACCAGCCTCGAACTCACCA3'). The consensus sequence for each sample was aligned to the reference sequence (JF740867.1) using BLASTn, revealing all the similarities of more than 99.5% (Supplementary File 2). The morphological characteristics (colony, pink pigment, shape of macroconidia, absence of microconidia) (Leslie and Summerell, 2006) and sequencing results indicated that the seven isolates from wheat were F. graminearum of the 3ADON chemotype. Besides, Koch's postulates were performed by spray-inoculating healthy inflorescences of eight wheat plants derived from the cross Avocet/CDC Silex at half anthesis stage (one isolate per plant and one non-inoculated control). Each spike was thoroughly sprayed with 1ml of spore suspension containing 5 × 104 conidia per ml (4-5 spikes per plant). The spikes on one plant were treated with distilled water (1 ml per spike) as a blank control. The inoculated spikes were covered with moist plastic bags for 48 hours, and the plants were placed in a growth chamber under a 12-h photoperiod at 18°C. Seven days later, spikes of the spores-treated plants exhibited bleached spikelets, which is a typical symptom of FHB, and there was no disease on the control plant. F. graminearum was re-isolated from FDK of diseased spikes using the isolation methodology and identified by morphology described above. To our knowledge and based on a literature review, this is the first report of F. graminearum causing FHB on wheat and barley in the Lower Mainland of British Columbia. The reason for the concealment of F. graminearum in BC might be the small acreage of commercially grown small-grain cereals. Further, there is limited cultivation of winter wheat and barley in the region for forage/silage, but the crops are harvested at the soft dough stage leaving limited grain/spike residue for the next crop. While presently there is very low acreage of cereal host crops of F. gramineraum in Lower Mainland, this acreage might increase in future years as winter cereals are slowly expanding in the region as cover crops, forages, and even grain production for sale to forgae producers or for local breweries in case of barley; therefore, finding of F. gramineraum could have economic consequences on cereal production in the region in future. Further investigation is needed to better understand the aggressiveness of the strains and their population structure of the pathogen in the Region.

First report of Uromyces rumicis on Rumex crispus in Canada

Rumex crispus L. (curled dock) is a noxious weed in both grasslands (mainly pastures) and arable lands, but is also an early colonizer of many disturbed areas in lowland and upland regions. Rumex crispus is of agricultural significance because it competes with sown or native pasture and crops species and occupies areas that could be utilized by more palatable crop species. Rumex crispus can grow on almost all soil types but less often on peat and acidic soils. The range of altitude to which the species has become adapted varies from sea level to 3,500 m (Zaller 2004). This plant species has Eurasian origin and is widely distributed through temperate regions of North America as an introduced species. There is no previous rust report on R. crispus in Canada. On other Rumex species two Puccinia species viz. Puccinia acetosae (Schumach.) Körn., and P. ornata Arthur & Holw., have been previously reported from Canada (Farr & Rossman 2022). During the recent field survey from southern British Columbia, Langley, heavily rust infected leaves of R. crispus were observed. Uredinia and telia were present on both sides of the leaf mainly on the lower side. Uredinia early exposed, brown, and pulverulent. Urediniospores were obovoid, ellipsoid or oblong, measuring 20-28 × 17-23 µm. Urediniospore walls are yellowish brown to brown, 1.5-2 µm thick; covered in evenly distributed echinulae, spaced 2 to 3 μm apart, with smooth (non-echinulate) patches at the equator of the urediniospores. Urediniospores with 2- (mostly 3 and less often 2) germ pores, usually supraequatorial (at the upper part of the spore), or distributed irregularly (scattered), or 2 germ pores supraequatorial, one equatorial or all germ pores equatorial, germ pores covered with flat papilla. Telia similar to the uredinia, dark brown. Teliospores more or less globoid, ellipsoid, broadly ellipsoid, obovoid or oblong, 25--36 × 15-23 µm, brownish yellow to brown, smooth, 2-3 um thick, with apical or sup-apical germ pore, covered with a hemispherical, yellowish papilla, pedicels colorless, short. The above-mentioned characters fit Majewski's (1977) description for Uromyces rumicis (Schumach.) G. Winter. To confirm identity, the first 903 bp of the 5' end of the 28S rDNA of the above specimen was amplified following protocols of Aime (2006) and Aime et al. (2018) (GenBank accession no. ON166844). BLAST queries of the sequence shared 99.56% identity (900/903) with U. rumicis (GenBank accession no. KY764197). To our knowledge this is the first report of U. rumicis from Canada (Farr and Rossma 2022). There is only one previous published report of this rust species in North America made by French (1989) who reported U. rumicis on R. crispus from California. Uromyces rumicis is quite common on Rumex species including R. crispus in Eurasia and has also been reported on this host from Africa (Farr and Rossman 2022). It appears that the above rust fungus species may have been introduced to the North America by accompanying its host plant. A voucher specimen of infected R. crispus with U. rumicis was deposited at Arthur Fungarium (PUR) under the accession number PUR N24014. Uromyces rumicis is a heteromacrocyclic rust with aecial state on Ranunculaceae members especially Ranunculus ficaria L. This species is another introduced plant in North America. However, there is no report of the aecial state of this rust in North America to date. Existence of only two reports of U. rumicis in California and British Columbia, making it likely that U. rumicis became established in the West Coast of North America probably no earlier than the second half of the 20th century.

A152 NATURAL HISTORY OF SMALL BOWEL STRICTURES IN CROHN’S DISEASE

Background

Crohn’s disease (CD) is a progressive inflammatory disease that often results in intestinal complications such as small bowel (SB) strictures. SB strictures are frequently associated with substantial morbidity and may require surgery. The natural history of SB strictures in the era of biologic treatments has not been well characterized.

Aims

To determine the proportion of patients with SB strictures who develop complicated stricturing disease and to identify clinical factors associated with this outcome.

Methods

We performed a retrospective observational study between January 1, 2009, and May 31, 2019. Adults (>17 years) with CD who underwent an abdominal CT scan or MRI were identified from our institutional data warehouse using the ICD-10 code K50* and local imaging codes. Reports were reviewed to determine the imaging protocol and the presence of SB strictures. We included CT or MR enterography studies that reported SB strictures and excluded encounters with incomplete records, diverting ostomies, ileal J-pouches, and patients evaluated for pre-surgical planning. Each imaging study was included as a separate encounter in our analysis. Our primary endpoint was the development of complicated stricturing disease defined as stricture-related hospitalization or surgery. Time to event was estimated using Kaplan–Meier analysis and associated factors were assessed by multivariable Cox proportional hazard models adjusted for age, sex, exposure to biologics and corticosteroids.

Results

A total of 6583 unique imaging studies were identified: 926 (14%) studies reported SB strictures without penetrating complications, and 568 (9%) studies reported penetrating complications. A total of 503 (8%) studies, performed on 330 patients, met our inclusion criteria: mean age 42 (SD, 15.1) years and 166 (50%) males. Overall, 144 (44%) patients developed complicated stricturing disease: 106 (32%) patients required surgery and 132 (40%) patients were hospitalized for stricture related complications. Of the patients who underwent surgery, the mean time to surgery was 13 months (SD, 18.3) and among patients who required hospitalization, mean time to hospitalization was 15 months (SD, 17.8) (Figure 1). On multivariable analysis, exposure to corticosteroids (aHR 2.11; 95% CI, 1.54–2.90; p<0.001) but not biologics (aHR 1.1; 95% CI, 0.84–1.43; p<0.48) at the time of the imaging study was independently associated with the development of complicated stricturing disease.

Conclusions

In our single center study, complicated stricturing disease occurred in 44% of patients with CD who had a SB stricture and was associated with corticosteroids but not biologics.These findings, along with additional clinical and radiologic factors may help in the development of clinical support tools to identify patients at highest risk of developing complicated stricturing disease.

Funding Agencies

None

Prevalence of Molecular Subtypes in Operated Cases of Breast Cancer and Its Clinicopathological Correlation: A Single Institute Study from a Tertiary Cancer Centre in North India

Breast cancer has emerged as a major health problem among women in India. There are few Indian studies which have looked at prevalence of molecular subtypes of breast cancer in Indian population. The primary objective of our study was to find out the prevalence of various molecular subtypes in operated cases of breast cancer patients presenting to us. Three hundred sixty patients who were operated in our department were analysed. Clinicopathological features of all cases were recorded. Classification into various molecular subtypes was done using St. Gallen 2013 criteria. Luminal B HER2 negative was the predominant molecular subtype in our study population constituting 30.3% of patients. The percentage of aggressive subtypes, viz. triple negative breast cancer and HER2 enriched, were 21.7% and 11.4% respectively. Only 19.4% of patients in our study population had tumour size ≤ 2 cm with nodes being positive in 56.9% of our patients at presentation. Data from our study and other studies published from India show that the two most aggressive subtypes of, viz. triple negative breast cancer and HER2 enriched, may be more prevalent in our population as compared to western population.

Genetic factors affecting Fusarium head blight resistance improvement from introgression of exotic Sumai 3 alleles (including Fhb1, Fhb2, and Fhb5) in hard red spring wheat

BACKGROUND

Fusarium head blight resistance genes, Fhb1 (for Type-II resistance), Fhb2 (Type-II), and Fhb5 (Type-I plus some Type-II), which originate from Sumai 3, are among the most important that confer resistance in hexaploid wheat. Near-isogenic lines (NILs), in the CDC Alsask (susceptible; n = 32) and CDC Go (moderately susceptible; n = 38) backgrounds, carrying these genes in all possible combinations were developed using flanking microsatellite markers and evaluated for their response to FHB and deoxynivalenol (DON) accumulation in eight environments. NILs were haplotyped with wheat 90 K iSelect assay to elucidate the genomic composition and confirm alleles' presence. Other than evaluating the effects of three major genes in common genetic background, the study elucidated the epistatic gene interactions as they influence FHB measurements; identified loci other than Fhb1, Fhb2, and Fhb5, in both recurrent and donor parents and examined annotated proteins in gene intervals.

RESULTS

Genotyping using 81,857 single nucleotide polymorphism (SNP) markers revealed polymorphism on all chromosomes and that the NILs carried < 3% of alleles from the resistant donor. Significant improvement in field resistance (Type-I + Type-II) resulted only among the CDC Alsask NILs, not the CDC Go NILs. The phenotypic response of NILs carrying combinations of Sumai 3 derived genes suggested non-additive responses and Fhb5 was as good as Fhb1 in conferring field resistance in both populations. In addition to Fhb1, Fhb2, and Fhb5, four to five resistance improving alleles in both populations were identified and three of five in CDC Go were contributed by the susceptible parent. The introgressed chromosome regions carried genes encoding disease resistance proteins, protein kinases, nucleotide-binding and leucine rich repeats' domains. Complex epistatic gene-gene interactions among marker loci (including Fhb1, Fhb2, Fhb5) explained > 20% of the phenotypic variation in FHB measurements.

CONCLUSIONS

Immediate Sumai 3 derivatives carry a number of resistance improving minor effect alleles, other than Fhb1, Fhb2, Fhb5. Results verified that marker-assisted selection is possible for the introgression of exotic FHB resistance genes, however, the genetic background of the recipient line and epistatic interactions can have a strong influence on expression and penetrance of any given gene.

Fungicide and Cultivar Management of Leaf Spot Diseases of Winter Wheat in Western Canada

A complex of leaf-spotting diseases-tan spot, the Septoria complex, spot blotch, and powdery mildew-are frequently observed on winter wheat in western Canada; however, there are few studies indicating varietal differences in reaction to these diseases or the benefit of fungicide application. To determine the benefit of varietal improvement and multiple fungicide treatments and application timings, field experiments were conducted at six site-years in western Canada. Two cultivars varying in reaction to leaf spot diseases were used in combination with fungicide treatments. Disease severity ranged from trace to 64% of the combined flag and penultimate leaf area diseased, differed between cultivars, and was reduced from the check by some fungicide treatments. Yield improvement by fungicide treatment varied from 3.3 to 13.2% greater than the nontreated check. At two site-years, the split application of two half rates of fungicide resulted in the greatest yield; however, in both cases, the yield benefit did not differ from a single application at the flag leaf growth stage. Cultivar selection and fungicide use under environments conducive to disease are beneficial components of an integrated leaf spot disease management program for winter wheat in western Canada.

Race Characterization of Puccinia striiformis f. sp. tritici, the Cause of Wheat Stripe Rust, in Saskatchewan and Southern Alberta, Canada and Virulence Comparison with Races from the United States

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, has been common across Saskatchewan, Canada since 2000. Fifty-nine isolates of P. striiformis f. sp. tritici, the majority of which were collected between 2011 and 2013 from Saskatchewan and southern Alberta, were analyzed for virulence frequency and diversity and compared with isolates characterized in the Pacific Northwest and Great Plains regions of the United States. In all, 31 wheat differentials, including 20 near-isogenic lines and 1 triticale variety, differentiated 59 P. striiformis f. sp. tritici isolates into 33 races, of which one race, C-PST-1, represented 31% of the isolates. None of the races were virulent on Yr5, Yr15, or YrSP. Virulence frequency ranged from 65 to 98% on YrA, Yr2, Yr8, Yr9, Yr27, Yr29, Yr32, YrSu, 'Heines VII', and 'Nord Deprez'. Race C-PST-6 was virulent on the greatest number of the differentials (n = 25) and C-PST-18 on the fewest (n = 14). Discriminant analysis of principal components and multivariate cluster analyses detected three and four major groups, respectively, which differed from each other in terms of virulence spectrum and year of collection. The diversity of the P. striiformis f. sp. tritici population in southern Alberta was greater than in Saskatchewan, which indicated that, although P. striiformis f. sp. tritici is primarily windborne over great distances and does not usually overwinter, there are detectable differences in virulence between these regions of western Canada. Comparative analyses of virulence frequency of Saskatchewan or southern Alberta isolates with isolates representing races from the Great Plains and the Pacific Northwest of the United States indicated greater similarity of Saskatchewan races to the Great Plains despite strong correlations with both parts of the United States. This suggests that the P. striiformis f. sp. tritici population in Saskatchewan is a mixture of inoculum from both parts of the United States.

Uranium: A Dentist's perspective

Uranium is a naturally occurring radionuclide found in granite and other mineral deposits. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). On an average, 1% – 2% of ingested uranium is absorbed in the gastrointestinal tract in adults. The absorbed uranium rapidly enters the bloodstream and forms a diffusible ionic uranyl hydrogen carbonate complex (UO2HCO3+) which is in equilibrium with a nondiffusible uranyl albumin complex. In the skeleton, the uranyl ion replaces calcium in the hydroxyapatite complex of the bone crystal. Although in North India, there is a risk of radiological toxicity from orally ingested natural uranium, the principal health effects are chemical toxicity. The skeleton and kidney are the primary sites of uranium accumulation. Acute high dose of uranyl nitrate delays tooth eruption, and mandibular growth and development, probably due to its effect on target cells. Based on all previous research and recommendations, the role of a dentist is to educate the masses about the adverse effects of uranium on the overall as well as the dental health. The authors recommended that apart from the discontinuation of the addition of uranium to porcelain, the Public community water supplies must also comply with the Environmental Protection Agency (EPA) standards of uranium levels being not more than 30 ppb (parts per billion).

Comparison of Scheimpflug imaging and spectral domain anterior segment optical coherence tomography for detection of narrow anterior chamber angles

PURPOSE

To compare the performance of anterior chamber volume (ACV) and anterior chamber depth (ACD) obtained using Scheimpflug imaging with angle opening distance (AOD500) and trabecular-iris space area (TISA500) obtained using spectral domain anterior segment optical coherence tomography (SD-ASOCT) in detecting narrow angles classified using gonioscopy.

METHODS

In this prospective, cross-sectional observational study, 265 eyes of 265 consecutive patients underwent sequential Scheimpflug imaging, SD-ASOCT imaging, and gonioscopy. Correlations between gonioscopy grading, ACV, ACD, AOD500, and TISA500 were evaluated. Area under receiver operating characteristic curve (AUC), sensitivity, specificity, and likelihood ratios (LRs) were calculated to assess the performance of ACV, ACD, AOD500, and TISA500 in detecting narrow angles (defined as Shaffer grade ≤1 in all quadrants). SD-ASOCT images were obtained at the nasal and temporal quadrants only.

RESULTS

Twenty-eight eyes (10.6%) were classified as narrow angles on gonioscopy. ACV correlated with gonioscopy grading (P<0.001) for temporal (r=0.204), superior (r=0.251), nasal (r=0.213), and inferior (r=0.236) quadrants. ACV correlated with TISA500 for nasal (r=0.135, P=0.029) and temporal (P=0.160, P=0.009) quadrants and also with AOD500 for nasal (r=0.498, P<0.001) and temporal (r=0.517, P<0.001) quadrants. For detection of narrow angles, ACV (AUC=0.935; 95% confidence interval (CI) =0.898-0.961) performed similar to ACD (AUC=0.88, P=0.06) and significantly better than AOD500 nasal (AUC=0.761, P=0.001), AOD500 temporal (AUC=0.808, P<0.001), TISA500 nasal (AUC=0.756, P<0.001), and TISA500 temporal (AUC=0.738, P<0.001). Using a cutoff of 113 mm(3), ACV had 90% sensitivity and 88% specificity for detecting narrow angles. Positive and negative LRs for ACV were 8.63 (95% CI=7.4-10.0) and 0.11 (95% CI=0.03-0.4), respectively.

CONCLUSIONS

ACV measurements using Scheimpflug imaging outperformed AOD500 and TISA500 using SD-ASOCT for detecting narrow angles.

Intracameral amphotericin B: initial experience in severe keratomycosis

PURPOSE

Fungal keratitis is a significant cause of ocular morbidity in India. The most commonly implicated fungi are Aspergillus spp. Patients often present with hypopyon, which usually contains fungal elements. The treatment is difficult owing to poor intraocular penetration of most available antifungal agents. This study evaluated the results of intracameral injection of amphotericin B in natamycin resistant cases of severe keratomycosis.

METHODS

Three patients of culture proven Aspergillus flavus corneal ulcer with hypopyon not responding to topical natamycin 5%, amphotericin B 0.15%, and oral itraconazole were administered intracameral amphotericin B. The first case received 7.5 microg in 0.1 mL followed by two subsequent injections of 10 microg in 0.1 mL each, the second case received two injections of 10 microg in 0.1 mL, and the third patient received a single dose of 10 microg in 0.1 mL. Culture of the aqueous sample also grew A. flavus in all three cases.

RESULTS

All three cases responded favorably, with the ulcer and hypopyon clearing completely. There was no clinical evidence of corneal or lenticular toxicity in any patient.

CONCLUSIONS

Intracameral amphotericin B may be a useful modality in the treatment of severe keratomycosis not responding to topical natamycin. It ensures adequate drug delivery into the anterior chamber and may be especially useful to avoid surgical intervention in the acute stage of the disease.

Neodymium:YAG capsulotomy rates following phacoemulsification with implantation of PMMA, silicone, and acrylic intraocular lenses

BACKGROUND AND OBJECTIVE

Posterior capsular opacification (PCO) is the most common visually disabling sequela of modern cataract surgery. Methods of reducing its incidence include the development of newer surgical techniques and intraocular lens (IOL) materials and designs. The aim of this study was to compare the incidence and time interval of development of PCO, and the requirement of laser capsulotomy in patients implanted with a polymethylmethacrylate (PMMA), silicone, or acrylic IOL.

PATIENTS AND METHODS

The data of 340 consecutive patients who underwent phacoemulsification and implantation ofa PMMA, silicone, or acrylic intraocular lens were analyzed. The aim of this study was to compare the incidence and time interval of development of PCO, and the requirement of laser capsulotomy in patients implanted with a PMMA, silicone, or acrylic IOL.

RESULTS

The incidence of PCO was found to be significantly less in the acrylic group (6.5% as compared to 21.74% and 26.6% in the PMMA and silicone groups, respectively; P = 0.01297 and 0.0039). Most patients (65%) exhibiting PCO in the PMMA group developed it within the first six months. In the silicone group, development of PCO was delayed. In 60% of patients, it appeared 18 months after surgery. Neodymium:YAG capsulotomy was required in 45% and 60% of patients developing PCO in the PMMA and silicone groups, respectively, while it was required in only 1 of the 4 patients developing PCO in the acrylic group.

CONCLUSION

This study indicates that implantation of an acrylic IOL helps reduce the incidence of PCO as well as the need for Nd:YAG capsulotomy. PMMA IOLs require Nd:YAG capsulotomy earlier in the postoperative period as compared to silicone IOLs.

Effect of in-the-bag intraocular lens fixation on the prevention of posterior capsule opacification

PURPOSE

To compare the incidence of posterior capsule opacification (PCO) after extracapsular cataract extraction (ECCE) and phacoemulsification and to evaluate the role of posterior chamber intraocular lens (PC IOL) haptic fixation and biomaterial/design in reducing the incidence.

SETTING

Postgraduate Institute of Medical Education and Research, Chandigarh, India; Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

This study comprised 278 eyes of 263 patients having ECCE and 318 eyes of 297 patients having phacoemulsification with PC IOL implantation. Posterior capsule opacification leading to a decrease in Snellen visual acuity of 2 or more lines was considered visually significant. The presence of PCO and IOL haptic fixation were evaluated postoperatively using slitlamp biomicroscopy. Haptic position was noted as in-the-bag (B-B), 1 haptic in the bag and 1 in the sulcus (bag-sulcus [B-S]), or both haptics out of the bag (sulcus-sulcus [S-S]). In addition, the rate of visually significant PCO was compared among 3 IOL biomaterials: poly(methyl methacrylate), silicone, and hydrophobic acrylic.

RESULTS

Visually significant PCO occurred in 42.45% of eyes having ECCE and 19.18% of eyes having phacoemulsification (P <.001, chi-square test) after a mean follow-up of 2.4 years +/- 0.7 (SD). In both groups, visually significant PCO was significantly less in eyes with B-B fixation than in those with B-S or S-S fixation (P <.001). The rate of visually significant PCO in all eyes in the phacoemulsification group with B-B fixation was low (11.90%) and was significantly lower in eyes with a hydrophobic acrylic IOL (2.22%; P <.05, chi-square test).

CONCLUSIONS

In-the-bag PC IOL fixation is required to consistently reduce the incidence of PCO. Thorough removal of lens substance, including hydrodissection-assisted cortical cleanup, and in-the-bag PC IOL fixation seem to be the most important factors in reducing PCO, regardless of surgical procedure or IOL type used. Intraocular lens biomaterial and design also help prevent PCO.

Postoperative complications and visual results in uniocular pediatric traumatic cataract

BACKGROUND AND OBJECTIVES

This study was prospectively carried out to evaluate the postoperative complications and visual results following posterior chamber intraocular lens (PCIOL) implantation in children with unilateral traumatic cataract.

PATIENTS AND METHODS

We prospectively evaluated 40 children, 12 years or younger, with traumatic cataract (blunt trauma, n = 22 eyes, repaired penetrating eye injury, n = 18 eyes) undergoing PCIOL implantation with a minimum follow-up period of one year. Children with posterior segment ocular injury were excluded.

RESULTS

The postoperative complications were significantly higher in the penetrating eye injury group as compared to blunt trauma group (ie, pupillary capture 44.44% vs 9.09%, posterior capsulotomy rate 83.33% vs 40.90% and IOL decentration 27.77% vs 4.54%). The final visual acuity was 6/12 or better in 38.8% and 86.36% of eyes with penetrating eye injury and blunt trauma, respectively.

CONCLUSION

Extracapsular cataract extraction (ECCE) with PCIOL implantation in traumatic cataract following blunt trauma results in better visual outcome and fewer complications compared to penetrating eye injury if the posterior segment is not involved.

Traumatic lens abscess with chornic endophthalmitis successfully treated with pars plana lensectomy and vitrectomy

Intralenticular abscess is a rare entity and has been infrequently reported after surgery, metastatic infection, or trauma. We report a case of post traumatic lens abscess with low-grade endophthalmitis following a penetrating eye injury with a splinter of wood. The patient was successfully treated with a pars plana lensectomy and vitrectomy. Despite thorough microbiological investigations, no causative organism could be isolated.

Prevention of postoperative infections in ophthalmic surgery

Postoperative endophthalmitis is a serious, vision-threatening complication of intraocular surgery. Better instrumentation, surgical techniques, prophylactic antibiotics and better understanding of asepsis have significantly reduced the incidence of this complication. Postoperative endophthalmitis may occur as an isolated event or as a cluster infection. Topical antibiotics, preoperative periocular preparation with povidone-iodine combined with a sterile operating room protocol significantly reduce the incidence of isolated postoperative endophthalmitis. The role of antibiotics in the irrigating fluid and subconjunctival antibiotics remains controversial. Cluster infections on the other hand are more likely to occur due to the use of contaminated fluids/viscoelastics or a breach in operating room asepsis. Prevention of postoperative endophthalmitis requires strict adherence to operating room norms, with all involved personnel discharging their assigned roles faithfully.

Bacterial adherence to polymethylmethacrylate posterior chamber intra ocular lenses

PURPOSE

Bacterial adherence to intraocular lenses (IOLs) has been incriminated in the pathogenesis of postoperative endophthalmitis. Staphylococcus epidermidis is the most common organism isolated. We studied the in-vitro adhesion of Staphylococcus epidermidis to Polymethylmethacrylate (PMMA) IOLs and the effect of duration of exposure to adherence.

METHODS

Two groups of 10 IOLs each were incubated in Staphylococcus epidermidis suspension for 2 minutes and 20 minutes respectively. Adhesion of bacterial cells was determined by counting the number of viable bacteria attached to IOLs.

RESULTS

The mean bacterial adherence with 2 minutes incubation was 12,889 +/- 7,150 bacteria/ IOL and with 20 minutes incubation was 84,226 +/- 35,024 bacteria/IOL (P< 0.01).

CONCLUSION

Our results show that Staphylococcus epidermidis adheres to PMMA IOLs in vitro and the degree of adherence is less for shorter duration of exposure. We conclude that viable bacteria irreversibly adherent to IOLs may play a role in the pathogenesis of postoperative endophthalmitis. Shorter duration of operative manipulation and exposure to contaminating sources may decrease the chances of postoperative endophthalmitis.

Curvularia lunata endophthalmitis with secondary keratitis

PURPOSE

To report a case of pseudophakic endophthalmitis with secondary keratitis caused by Curvularia lunata.

METHODS

A 40-year-old man presented with a fluffy mass in the anterior chamber with low-grade delayed postoperative inflammation in the right eye.

RESULTS

The anterior chamber and vitreous aspirate demonstrated C. lunata. A large corneal infiltrate developed after aspiration of the mass. Treatment with systemic, topical, and intraocular antifungal agents cleared the vitreous, but the cornea perforated.

CONCLUSION

Delayed low-grade infection with a fluffy mass in the anterior chamber after cataract surgery can rarely be a clinical presentation of dematiaceous fungal infection. Secondary keratitis may result after a diagnostic aspiration.

Visual results and postoperative complications of capsular bag and ciliary sulcus fixation of posterior chamber intraocular lenses in children with traumatic cataracts

PURPOSE

To evaluate the visual results and postoperative complications of capsular bag and ciliary sulcus fixation of posterior chamber intraocular lenses (IOLs) for traumatic cataracts in children.

SETTING

Department of Ophthalmology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.

METHODS

Twenty children (20 eyes) with traumatic cataracts had extracapsular cataract extraction (ECCE) and posterior chamber IOL implantation. They were randomly divided into 2 groups. Capsular bag fixation was performed in 10 children (Group A) and ciliary sulcus fixation in the other 10 (Group B). Traumatic cataracts associated with large corneal lacerations (10.0 mm or more), hyphema, angle recession, or posterior segment involvement were excluded. The best corrected visual acuity (BCVA) as well as early and delayed postoperative complications were prospectively evaluated in both groups.

RESULTS

The BCVA was 6/12 or better in 9 eyes (90%) in Group A and 8 eyes (80%) in Group B at the end of the mean follow-up (24.6 months +/- 10.6 [SD]). Amblyopia (1 eye in Group A) and corneal scar and commotio retinae (1 eye each in Group B) accounted for a visual acuity of worse than 6/12. The residual refractive error did not exceed 3.50 diopters in either group. The incidences of fibrinous anterior uveitis and pupillary capture were significantly higher in Group B (P < .05, Fisher exact test).

CONCLUSION

Capsular bag fixation of posterior chamber IOLs provided visual results similar to those with ciliary sulcus fixation but was associated with fewer postoperative complications, particularly uveitis and pupillary capture. This represents another important reason to attempt in-the-bag fixation in cases of traumatic cataract.

Response of Soybean Lines to Differentially Selected Cultures of Soybean Cyst Nematode Heterodera glycines Ichinohe

Eight soybean cyst nematode, Heterodera glycines Ichinohe, cultures were developed by their continuous selection on soybean lines with various level of resistance. Each soybean line was inoculated with eggs and larvae of the eight cultures. Female development was much higher on 'Essex' and 'Forrest' than the other lines. The development of nematode cultures selected on Essex and Forrest was low on the other six soybean lines compared with the lines on which they were selected. PI 89772 and PI 90763 had a high level of resistance to the culture selected on PI 88788, whereas cultures selected on PI 89772 and PI 90763 reproduced very little on PI 88788 and PI 209352. Cultures selected on PI 87631-1, PI 209332, and 'Cloud' gave response similar to that of PI 88788. The use of various sources for resistant variety development program is discussed.