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Storey PP, Tauqeer Z, Yonekawa Y, Todorich B, Wolfe JD, Shah SP, Shah AR, Koto T, Abbey AM, Morizane Y, Sharma P, Wood EH, Morizane-Hosokawa M, Pendri P, Pancholy M, Harkey S, Jeng-Miller KW, Obeid A, Borkar DS, Chen E, Williams P, Okada AA, Inoue M, Shiraga F, Hirakata A, Shah CP, Prenner J, Garg S, Garg S. The Impact of Prefilled Syringes on Endophthalmitis Following Intravitreal Injection of Ranibizumab. Am J Ophthalmol 2019;199:200-208.Abstract
PURPOSE: To compare the rates of infectious endophthalmitis following intravitreal injection of ranibizumab using prefilled syringes vs conventional preparation. DESIGN: Multicenter retrospective cohort study. METHODS: All eyes receiving intravitreal injection of 0.5 mg ranibizumab for retinal vascular diseases at 10 retina practices across the United States (2016 to 2017) and Japan (2009 to 2017) were included. The total numbers of eyes and injections were determined from billing codes. Endophthalmitis cases were determined from billing records and evaluated with chart review. Primary outcome was the rate of postinjection acute endophthalmitis. Secondary outcomes were visual acuity and microbial spectrum. RESULTS: A total of 243 754 intravitreal 0.5 mg ranibizumab injections (165 347 conventional and 78 407 prefilled) were administered to 43 132 unique patients during the study period. In the conventional ranibizumab group, a total of 43 cases of suspected endophthalmitis occurred (0.026%; 1 in 3845 injections) and 22 cases of culture-positive endophthalmitis occurred (0.013%; 1 in 7516 injections). In the prefilled ranibizumab group, 12 cases of suspected endophthalmitis occurred (0.015%; 1 in 6534 injections) and 2 cases of culture-positive endophthalmitis occurred (0.0026%; 1 in 39 204 injections). Prefilled syringes were associated with a trend toward decreased risk of suspected endophthalmitis (odds ratio 0.59; 95% confidence interval 0.31-1.12; P = .10) and a statistically significant decreased risk of culture-positive endophthalmitis (odds ratio 0.19; 95% confidence interval 0.045-0.82; P = .025). Average logMAR vision loss at final follow-up was significantly worse for eyes that developed endophthalmitis from the conventional ranibizumab preparation compared to the prefilled syringe group (4.45 lines lost from baseline acuity vs 0.38 lines lost; P = .0062). Oral-associated flora was found in 27.3% (6/22) of conventional ranibizumab culture-positive endophthalmitis cases (3 cases of Streptococcus viridans, 3 cases of Enterococcus faecalis) compared to 0 cases in the prefilled ranibizumab group. CONCLUSION: In a large, multicenter, retrospective study the use of prefilled syringes during intravitreal injection of ranibizumab was associated with a reduced rate of culture-positive endophthalmitis, including from oral flora, as well as with improved visual acuity outcomes.
Paschalis EI, Lei F, Zhou C, Chen XN, Kapoulea V, Hui P-C, Dana R, Chodosh J, Vavvas DG, Dohlman CH. Microglia Regulate Neuroglia Remodeling in Various Ocular and Retinal Injuries. J Immunol 2019;202(2):539-549.Abstract
Reactive microglia and infiltrating peripheral monocytes have been implicated in many neurodegenerative diseases of the retina and CNS. However, their specific contribution in retinal degeneration remains unclear. We recently showed that peripheral monocytes that infiltrate the retina after ocular injury in mice become permanently engrafted into the tissue, establishing a proinflammatory phenotype that promotes neurodegeneration. In this study, we show that microglia regulate the process of neuroglia remodeling during ocular injury, and their depletion results in marked upregulation of inflammatory markers, such as , , and in the retina, and abnormal engraftment of peripheral CCR2 CX3CR1 monocytes into the retina, which is associated with increased retinal ganglion cell loss, retinal nerve fiber layer thinning, and pigmentation onto the retinal surface. Furthermore, we show that other types of ocular injuries, such as penetrating corneal trauma and ocular hypertension also cause similar changes. However, optic nerve crush injury-mediated retinal ganglion cell loss evokes neither peripheral monocyte response in the retina nor pigmentation, although peripheral CX3CR1 and CCR2 monocytes infiltrate the optic nerve injury site and remain present for months. Our study suggests that microglia are key regulators of peripheral monocyte infiltration and retinal pigment epithelium migration, and their depletion results in abnormal neuroglia remodeling that exacerbates neuroretinal tissue damage. This mechanism of retinal damage through neuroglia remodeling may be clinically important for the treatment of patients with ocular injuries, including surgical traumas.
Lahola-Chomiak AA, Footz T, Nguyen-Phuoc K, Neil GJ, Fan BJ, Allen KF, Greenfield DS, Parrish RK, Linkroum K, Pasquale LR, Leonhardt RM, Ritch R, Javadiyan S, Craig JE, Allison WT, Lehmann OJ, Walter MA, Wiggs JL. Non-Synonymous variants in premelanosome protein (PMEL) cause ocular pigment dispersion and pigmentary glaucoma. Hum Mol Genet 2019;28(8):1298-1311.Abstract
Pigmentary glaucoma (PG) is a common glaucoma subtype that results from release of pigment from the iris, called pigment dispersion syndrome (PDS), and its deposition throughout the anterior chamber of the eye. Although PG has a substantial heritable component, no causative genes have yet been identified. We used whole exome sequencing of two independent pedigrees to identify two premelanosome protein (PMEL) variants associated with heritable PDS/PG. PMEL encodes a key component of the melanosome, the organelle essential for melanin synthesis, storage and transport. Targeted screening of PMEL in three independent cohorts (n = 394) identified seven additional PDS/PG-associated non-synonymous variants. Five of the nine variants exhibited defective processing of the PMEL protein. In addition, analysis of PDS/PG-associated PMEL variants expressed in HeLa cells revealed structural changes to pseudomelanosomes indicating altered amyloid fibril formation in five of the nine variants. Introduction of 11-base pair deletions to the homologous pmela in zebrafish by the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 method caused profound pigmentation defects and enlarged anterior segments in the eye, further supporting PMEL's role in ocular pigmentation and function. Taken together, these data support a model in which missense PMEL variants represent dominant negative mutations that impair the ability of PMEL to form functional amyloid fibrils. While PMEL mutations have previously been shown to cause pigmentation and ocular defects in animals, this research is the first report of mutations in PMEL causing human disease.
Hård A-L, Nilsson AK, Lund A-M, Hansen-Pupp I, Smith LEH, Hellström A. Review shows that donor milk does not promote the growth and development of preterm infants as well as maternal milk. Acta Paediatr 2019;108(6):998-1007.Abstract
AIM: This nonsystematic review examined differences in the composition of raw maternal breastmilk and pasteurised donor milk and possible health effects on preterm infants. METHODS: We searched PubMed up to July 2018 for studies published in English that focused on four comparisons as follows: raw maternal milk versus donor milk, human milk before and after Holder pasteurisation, milk from mothers who delivered preterm and at term and milk collected during early and late lactation. We also searched for possible effects of the milk components, as well as the effects of maternal and donor milk on preterm infants' health. RESULTS: Raw maternal milk contained factors involved in antioxidant and anti-inflammatory defence, gut microbiome establishment and the maturation of immune defences, food tolerability and metabolism. Many of these factors were reduced or abolished in processed donor milk. Both maternal milk and donor milk have been associated with a reduced incidence of necrotising enterocolitis. High-dose feeding with maternal milk during the neonatal period reportedly reduced the risk of other morbidities and promoted growth and neurodevelopment. CONCLUSION: Many of the components in raw maternal breastmilk were lacking in pasteurised donor milk, which was inferior in promoting the growth and development of very preterm infants.
Adil MY, Xiao J, Olafsson J, Chen X, Lagali NS, Ræder S, Utheim ØA, Dartt DA, Utheim TP. Meibomian Gland Morphology Is a Sensitive Early Indicator of Meibomian Gland Dysfunction. Am J Ophthalmol 2019;200:16-25.Abstract
PURPOSE: To investigate the relationship between meibomian gland (MG) morphology and clinical dry eye tests in patients with meibomian gland dysfunction (MGD). DESIGN: Cross-sectional study. SUBJECTS: Total 538 MGD patients and 21 healthy controls. METHODS: MG loss on meibography images of upper (UL) and lower lids (LL) was graded on a scale of 0 (lowest degree of MG loss) to 3. MG length, thickness, and interglandular space in the UL were measured. Clinical tests included meibum expression and quality, tear film break-up time, ocular staining, osmolarity, Schirmer I, blink interval timing, and Ocular Surface Disease Index (OSDI) questionnaire. RESULTS: Mean UL and LL meibogrades were significantly higher in MGD patients compared to controls (P < .001 for UL and LL). The sensitivity and specificity of the meibograde as a diagnostic parameter for MGD was 96.7% and 85%, respectively. Schirmer I was significantly increased in MGD patients with meibograde 1 compared to patients with meibograde 0, 2, and 3 in the UL (P < .05). MG thickness increased with higher meibograde (P < .001). MG morphology correlated significantly but weakly with several clinical parameters (P < .05). OSDI did not correlate with any MG morphologic parameter. CONCLUSIONS: Grading of MG loss using meibograde effectively diagnoses MGD. Compensatory mechanisms such as increased aqueous tear production and dilation of MGs make early detection of MGD difficult by standard clinical measures of dry eye, whereas morphologic analysis of MGs reveals an early stage of MGD, and therefore represents a complementary clinical parameter with diagnostic potential.
VanderVeen DK, Kraker RT, Pineles SL, Hutchinson AK, Wilson LB, Galvin JA, Lambert SR. Use of Orthokeratology for the Prevention of Myopic Progression in Children: A Report by the American Academy of Ophthalmology. Ophthalmology 2019;126(4):623-636.Abstract
PURPOSE: To review the published evidence to evaluate the ability of orthokeratology (Ortho-K) treatment to reduce myopic progression in children and adolescents compared with the use of spectacles or daytime contact lenses for standard refractive correction. METHODS: Literature searches of the PubMed database, the Cochrane Library, and the databases of clinical trials were last conducted on August 21, 2018, with no date restrictions but limited to articles published in English. These searches yielded 162 citations, of which 13 were deemed clinically relevant for full-text review and inclusion in this assessment. The panel methodologist then assigned a level of evidence rating to the selected studies. RESULTS: The 13 articles selected for inclusion include 3 prospective, randomized clinical trials; 7 nonrandomized, prospective comparative studies; and 3 retrospective case series. One study provided level I evidence, 11 studies provided level II evidence, and 1 study provided level III evidence. Most studies were performed in populations of Asian ethnicity. Change in axial length was the primary outcome for 10 of 13 studies and change in refraction was the primary outcome for 3 of 13 studies. In these studies, Ortho-K typically reduced axial elongation by approximately 50% over a 2-year study period. This corresponds to average axial length change values of approximately 0.3 mm for Ortho-K patients compared with 0.6 mm for control patients, which corresponds to a typical difference in refraction of approximately 0.5 diopters (D). Younger age groups and individuals with larger than average pupil size may have a greater effect with Ortho-K. Rebound can occur after discontinuation or change to alternative refractive treatment. CONCLUSIONS: Orthokeratology may be effective in slowing myopic progression for children and adolescents, with a potentially greater effect when initiated at an early age (6-8 years). Safety remains a concern because of the risk of potentially blinding microbial keratitis from contact lens wear.
Pollack S, Igo RP, Jensen RA, Christiansen M, Li X, Cheng C-Y, Ng MCY, Smith AV, Rossin EJ, Segrè AV, Davoudi S, Tan GS, Chen Y-DI, Kuo JZ, Dimitrov LM, Stanwyck LK, Meng W, Hosseini MS, Imamura M, Nousome D, Kim J, Hai Y, Jia Y, Ahn J, Leong A, Shah K, Park KH, Guo X, Ipp E, Taylor KD, Adler SG, Sedor JR, Freedman BI, Family Investigation of Nephropathy and Diabetes-Eye Research Group DCCT/EDICRG, Lee I-T, Sheu WH-H, Kubo M, Takahashi A, Hadjadj S, Marre M, Tregouet D-A, McKean-Cowdin R, Varma R, McCarthy MI, Groop L, Ahlqvist E, Lyssenko V, Agardh E, Morris A, Doney ASF, Colhoun HM, Toppila I, Sandholm N, Groop P-H, Maeda S, Hanis CL, Penman A, Chen CJ, Hancock H, Mitchell P, Craig JE, Chew EY, Paterson AD, Grassi MA, Palmer C, Bowden DW, Yaspan BL, Siscovick D, Cotch MF, Wang JJ, Burdon KP, Wong TY, Klein BEK, Klein R, Rotter JI, Iyengar SK, Price AL, Sobrin L. Multiethnic Genome-Wide Association Study of Diabetic Retinopathy Using Liability Threshold Modeling of Duration of Diabetes and Glycemic Control. Diabetes 2019;68(2):441-456.Abstract
To identify genetic variants associated with diabetic retinopathy (DR), we performed a large multiethnic genome-wide association study. Discovery included eight European cohorts ( = 3,246) and seven African American cohorts ( = 2,611). We meta-analyzed across cohorts using inverse-variance weighting, with and without liability threshold modeling of glycemic control and duration of diabetes. Variants with a value <1 × 10 were investigated in replication cohorts that included 18,545 European, 16,453 Asian, and 2,710 Hispanic subjects. After correction for multiple testing, the C allele of rs142293996 in an intron of nuclear VCP-like () was associated with DR in European discovery cohorts ( = 2.1 × 10), but did not reach genome-wide significance after meta-analysis with replication cohorts. We applied the Disease Association Protein-Protein Link Evaluator (DAPPLE) to our discovery results to test for evidence of risk being spread across underlying molecular pathways. One protein-protein interaction network built from genes in regions associated with proliferative DR was found to have significant connectivity ( = 0.0009) and corroborated with gene set enrichment analyses. These findings suggest that genetic variation in as well as variation within a protein-protein interaction network that includes genes implicated in inflammation, may influence risk for DR.
Woodward AM, Lehoux S, Mantelli F, Di Zazzo A, Brockhausen I, Bonini S, Argüeso P. Inflammatory Stress Causes N-Glycan Processing Deficiency in Ocular Autoimmune Disease. Am J Pathol 2019;189(2):283-294.Abstract
High levels of proinflammatory cytokines have been associated with a loss of tissue function in ocular autoimmune diseases, but the basis for this relationship remains poorly understood. Here we investigate a new role for tumor necrosis factor α in promoting N-glycan-processing deficiency at the surface of the eye through inhibition of N-acetylglucosaminyltransferase expression in the Golgi. Using mass spectrometry, complex-type biantennary oligosaccharides were identified as major N-glycan structures in differentiated human corneal epithelial cells. Remarkably, significant differences were detected between the efficacies of cytokines in regulating the expression of glycogenes involved in the biosynthesis of N-glycans. Tumor necrosis factor α but not IL-1β had a profound effect in suppressing the expression of enzymes involved in the Golgi branching pathway, including N-acetylglucosaminyltransferases 1 and 2, which are required for the formation of biantennary structures. This decrease in gene expression was correlated with a reduction in enzymatic activity and impaired N-glycan branching. Moreover, patients with ocular mucous membrane pemphigoid were characterized by marginal N-acetylglucosaminyltransferase expression and decreased N-glycan branching in the conjunctiva. Together, these data indicate that proinflammatory cytokines differentially influence the expression of N-glycan-processing enzymes in the Golgi and set the stage for future studies to explore the pathophysiology of ocular autoimmune diseases.
Nangia V, Jonas JB, George R, Lingam V, Ellwein L, Cicinelli MV, Das A, Flaxman SR, Keeffe JE, Kempen JH, Leasher J, Limburg H, Naidoo K, Pesudovs K, Resnikoff S, Silvester AJ, Tahhan N, Taylor HR, Wong TY, Bourne RRA, of the of Study VLEGGBD. Prevalence and causes of blindness and vision impairment: magnitude, temporal trends and projections in South and Central Asia. Br J Ophthalmol 2019;103(7):871-877.Abstract
BACKGROUND: To assess prevalence and causes of vision loss in Central and South Asia. METHODS: A systematic review of medical literature assessed the prevalence of blindness (presenting visual acuity<3/60 in the better eye), moderate and severe vision impairment (MSVI; presenting visual acuity <6/18 but ≥3/60) and mild vision impairment (MVI; presenting visual acuity <6/12 and ≥6/18) in Central and South Asia for 1990, 2010, 2015 and 2020. RESULTS: In Central and South Asia combined, age-standardised prevalences of blindness, MSVI and MVI in 2015 were for men and women aged 50+years, 3.72% (80% uncertainty interval (UI): 1.39-6.75) and 4.00% (80% UI: 1.41-7.39), 16.33% (80% UI: 8.55-25.47) and 17.65% (80% UI: 9.00-27.62), 11.70% (80% UI: 4.70-20.32) and 12.25% (80% UI:4.86-21.30), respectively, with a significant decrease in the study period for both gender. In South Asia in 2015, 11.76 million individuals (32.65% of the global blindness figure) were blind and 61.19 million individuals (28.3% of the global total) had MSVI. From 1990 to 2015, cataract (accounting for 36.58% of all cases with blindness in 2015) was the most common cause of blindness, followed by undercorrected refractive error (36.43%), glaucoma (5.81%), age-related macular degeneration (2.44%), corneal diseases (2.43%), diabetic retinopathy (0.16%) and trachoma (0.04%). For MSVI in South Asia 2015, most common causes were undercorrected refractive error (accounting for 66.39% of all cases with MSVI), followed by cataract (23.62%), age-related macular degeneration (1.31%) and glaucoma (1.09%). CONCLUSIONS: One-third of the global blind resided in South Asia in 2015, although the age-standardised prevalence of blindness and MSVI decreased significantly between 1990 and 2015.
Yin J, Jacobs DS. Long-term outcome of using Prosthetic Replacement of Ocular Surface Ecosystem (PROSE) as a drug delivery system for bevacizumab in the treatment of corneal neovascularization. Ocul Surf 2019;17(1):134-141.Abstract
PURPOSE: To report the long-term outcome of Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) for delivery of bevacizumab in the treatment of corneal neovascularization (KNV). METHODS: Retrospective, non-comparative, interventional case series of 13 sequential patients treated for KNV at the BostonSight between 2006 and 2017. In all cases, PROSE treatment was initiated for management of ocular surface disease and patients wore PROSE consistently on a daily wear basis prior to bevacizumab treatment. Patients applied a drop of 1% preservative free bevacizumab to the reservoir of PROSE device twice daily. Patients continued with daily wear of the device during treatment and afterwards. RESULTS: 13 patients (8 female and mean age of 45 years) are included with a mean follow-up of 5.1 years (range 6 months-11 years). Underlying ocular diagnoses included Stevens-Johnson syndrome (7), ocular chronic graft-versus-host disease (2), corneal transplant (2), contact lens-related corneal ulcer and limbal stem cell deficiency (1), and familial dysautonomia (1). Median duration of bevacizumab use was 6 months (range 3 months-10 years). Twelve cases (92%) had regression of KNV and 10 cases (77%) had improved best-corrected visual acuity (BCVA) with treatment. Median BCVA improved from -1.1 (LogMAR) at baseline, to -0.66 at end of bevacizumab treatment, and remained -0.63 at last follow-up (P = 0.047). KNV progressed in one eye after discontinuation of bevacizumab. There were no ophthalmic or systemic complications. CONCLUSIONS: Topical bevacizumab used in PROSE is effective in treating KNV and improving vision. Long-term follow-up reveals durable response and no complications.
Sun JK, Wang P-W, Taylor S, Haskova Z. Durability of Diabetic Retinopathy Improvement with As-Needed Ranibizumab: Open-Label Extension of RIDE and RISE Studies. Ophthalmology 2019;126(5):712-720.Abstract
PURPOSE: To evaluate the durability of diabetic retinopathy (DR) improvements after a change in ranibizumab dosing from monthly to individualized pro re nata (PRN) therapy. DESIGN: Pooled analysis of the open-label extension (OLE) of RIDE and RISE (clinicaltrials.gov identifiers, NCT00473382 and NCT00473330) patients with DR and diabetic macular edema (DME). PARTICIPANTS: Patients who completed 36-month participation in RIDE and RISE and entered the OLE. METHODS: In RIDE and RISE, patients (n = 759) were randomized 1:1:1 to ranibizumab 0.3 mg monthly, 0.5 mg monthly, or monthly sham injections with rescue macular laser available after 6 months, per protocol-specified criteria. After 24 months, sham patients crossed over to ranibizumab 0.5 mg monthly. After 36 months in the core studies, patients in the OLE (n = 500) could receive ranibizumab 0.5 mg PRN based on predefined DME re-treatment criteria. Diabetic retinopathy severity was evaluated photographically using the Early Treatment Diabetic Retinopathy Study DR severity scale. MAIN OUTCOME MEASURES: Change in DR severity from months 36 to 48 by re-treatment status. RESULTS: Among patients who entered the OLE, 121 of 500 (24%) did not require additional ranibizumab injections. Overall, 367 patients had evaluable DR at months 36 and 48. Among patients not requiring ranibizumab re-treatment from months 36 to 48 (88/367), 57% to 78%, 0% to 7%, and 22% to 36% experienced DR severity stability, 2-step or more improvement, and 2-step or more worsening, respectively. Among patients requiring ranibizumab re-treatment (279/367), 84% to 94%, 2%, and 3% to 14% experienced DR severity stability, 2-step or more improvement, and 2-step or more worsening, respectively. On average, vision improvements were maintained during the OLE regardless of change in DR severity. CONCLUSIONS: Diabetic retinopathy severity improvements with ranibizumab were maintained in over 70% of OLE patients after switching from ranibizumab monthly to an individualized ranibizumab 0.5 mg PRN dosing regimen. Because approximately one third of OLE patients experienced DR worsening, careful monitoring should be part of the long-term management of patients with DR.
Gupta A, El-Rami H, Barham R, Fleming A, van Hemert J, Sun JK, Silva PS, Aiello LP. Effect of phase-plate adjustment on retinal image sharpness and visible retinal area on ultrawide field imaging. Eye (Lond) 2019;33(4):587-591.Abstract
BACKGROUND: To evaluate changes in image sharpness across ultrawide field (UWF) images and the effect of phase-plate adjustment on image contrast and extent of visible retinal area (VRA). METHODS: This was a single site evaluation of 200° UWF images acquired with phase-plate adjustment (California, Optos, plc) and without (200TX, Optos, plc). Images were acquired using standardized protocol. VRA was manually outlined on each image and quantified using customized software. Mean image sharpness was evaluated using an automated method within the full VRA of each image and within the peripheral region of the VRA. The VRA and image sharpness were evaluated and compared between the two devices. RESULTS: Twenty eyes of 10 healthy volunteers were evaluated. Devices with and without phase-plate adjustment produced a similar extent of VRA. Eye steering increased VRA in devices with and without phase-plate adjustment by 39.3% and 34.3%, respectively. Regardless of gaze direction, mean sharpness of the full VRA was reduced in peripheral area with or without phase-plate adjustment. Compared to images without phase-plate adjustment, use of phase-plate adjustment reduced the loss of peripheral image sharpness in all fields (-4.2 to -26.0%; p < 0.001 all fields). The sharpness of the peripheral area for on-axis images was 61.5% higher with phase-plate adjustment. CONCLUSIONS: The use of phase-plate adjustment does not alter the extent of VRA. However, for on-axis images the loss of sharpness in the periphery is 4.5-fold less with phase-plate adjustment, potentially reducing the need to steer images and improving lesion detection in these areas.
Barros EM, Martin MJ, Selleck EM, Lebreton F, Sampaio JLM, Gilmore MS. Daptomycin Resistance and Tolerance Due to Loss of Function in Staphylococcus aureus dsp1 and asp23. Antimicrob Agents Chemother 2019;63(1)Abstract
Lipopeptide daptomycin is a last-line cell-membrane-targeting antibiotic to treat multidrug-resistant Alarmingly, daptomycin-resistant isolates have emerged. The mechanisms underlying daptomycin resistance are diverse and share similarities with resistances to cationic antimicrobial peptides and other lipopeptides, but they remain to be fully elucidated. We selected mutants with increased resistance to daptomycin from a library of transposon insertions in sequent type 8 (ST8) HG003. Insertions conferring increased daptomycin resistance were localized to two genes, one coding for a hypothetical lipoprotein (SAOUHSC_00362, Dsp1), and the other for an alkaline shock protein (SAOUHSC_02441, Asp23). Markerless loss-of-function mutants were then generated for comparison. All transposon mutants and knockout strains exhibited increased daptomycin resistance compared to those of wild-type and complemented strains. Null and transposon insertion mutants also exhibited increased resistance to cationic antimicrobial peptides. Interestingly, the mutant also showed increased resistance to vancomycin, a cell-wall-targeting drug with a different mode of action. Null mutations in both and resulted in increased tolerance as reflected by reduced killing to both daptomycin and vancomycin, as well as an increased tolerance to surfactant (Triton X-100). Neither mutant exhibited increased resistance to lysostaphin, a cell-wall-targeting endopeptidase. These findings identified two genes core to the species that make previously uncharacterized contributions to antimicrobial resistance and tolerance in .

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