1
|
Kaur P, Moon L, Srikumaran D, Salzberg SL, Lu J, Simner PJ, Soiberman US. No Evidence of Chronic Infection in a Metagenomic Sequencing Study of the Keratoconus Corneal Epithelium. J Clin Med 2024; 13:3399. [PMID: 38929928 PMCID: PMC11205138 DOI: 10.3390/jcm13123399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Revised: 06/05/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024] Open
Abstract
Objectives: This study aims to assess the presence of pathogenic microorganisms in the corneal epithelial layer of keratoconus patients. Methods: DNA was extracted from corneal epithelial samples procured from ten individual keratoconus eyes and three healthy controls. Metagenomic next-generation sequencing (mNGS) was performed to detect ocular microbiota using an agnostic approach. Results: Metagenomic sequencing revealed a low microbial read count in corneal epithelial samples derived from both keratoconus eyes (average: 530) and controls (average: 622) without a statistically significant difference (p = 0.29). Proteobacteria were the predominant phylum in both keratoconus and control samples (relative abundance: 72% versus 79%, respectively). Conclusions: The overall low microbial read count and the lack of difference in the relative abundance of different microbial species between keratoconus and control samples do not support the hypothesis that a chronic corneal infection is implicated in the pathogenesis of keratoconus. These findings do not rule out the possibility that an acute infection may be involved in the disease process as an initiating event.
Collapse
Affiliation(s)
- Pritpal Kaur
- The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Loren Moon
- The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Divya Srikumaran
- The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Steven L. Salzberg
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21218, USA
- Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jennifer Lu
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Patricia J. Simner
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Uri S. Soiberman
- The Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| |
Collapse
|
2
|
Zou XR, Zhang P, Zhou Y, Yin Y. Ocular surface microbiota in patients with varying degrees of dry eye severity. Int J Ophthalmol 2023; 16:1986-1995. [PMID: 38111925 PMCID: PMC10700088 DOI: 10.18240/ijo.2023.12.10] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/14/2023] [Indexed: 12/20/2023] Open
Abstract
AIM To elucidate the profiles of commensal bacteria on the ocular surfaces of patients with varying severity of dry eye (DE). METHODS The single-center, prospective, case-control, observational study categorized all participants into three distinct groups: 1) control group (n=61), 2) mild DE group (n=56), and 3) moderate-to-severe DE group (n=82). Schirmer's tear secretion strips were used, and the bacterial microbiota was analyzed using 16S ribosomal ribonucleic acid gene sequencing. RESULTS The three groups had significant differences in alpha diversity: the control group had the highest richness (Chao1, Faith's phylogenetic diversity), the mild DE group showed the highest diversity (Shannon, Simpson), and the moderate-to-severe DE group had the lowest of the above-mentioned indices. DE severity was positively correlated with a reduction in beta diversity of the microbial community, with the moderate-to-severe DE group exhibiting the lowest beta diversity. Linear discriminant analysis effect size presented distinct dominant taxa that significantly differed between each. Furthermore, the exacerbation of DE corresponded with the enrichment of certain pathogenic bacteria, as determined by random forest analysis. CONCLUSION As DE severity worsens, microbial community diversity tends to decrease. DE development corresponds with changes in microbial constituents, primarily characterized by reduced microbial diversity and a more homogenous species composition.
Collapse
Affiliation(s)
- Xin-Rong Zou
- Department of Ophthalmology, Fengcheng Hospital, Fengxian District, Shanghai 201411, China
- Fengcheng Branch, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 201411, China
| | - Pei Zhang
- Department of Ophthalmology, Huashan Hospital of Fudan University, Shanghai 200040, China
- Department of Ophthalmology, Gonghui Hospital, Jing'an District, Shanghai 200436, China
| | - Yuan Zhou
- Department of Ophthalmology, Fengcheng Hospital, Fengxian District, Shanghai 201411, China
- Fengcheng Branch, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 201411, China
| | - Yao Yin
- Department of Ophthalmology, Fengcheng Hospital, Fengxian District, Shanghai 201411, China
- Fengcheng Branch, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 201411, China
| |
Collapse
|
3
|
Cheng Y, An N, Ishaq HM, Xu J. Ocular microbial dysbiosis and its linkage with infectious keratitis patients in Northwest China: A cross-sectional study. Microb Pathog 2023; 184:106371. [PMID: 37741304 DOI: 10.1016/j.micpath.2023.106371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/25/2023]
Abstract
OBJECTIVES To evaluate the alteration of ocular surface microbiome of patients with infectious keratitis in northwest of China. METHODS The corneal scrapings, eyelid margin and conjunctiva samples were collected from 57 participants, who were divided into bacterial keratitis, fungal keratitis, viral keratitis and control group. The V3-V4 region of bacterial 16S rDNA in each sample was amplified and sequenced on the Illumina HiSeq 2500 sequencing platform, and the differences among different groups were compared bioinformatically. RESULTS Significant alterations of the microbiome were observed in alpha-diversity and beta-diversity analysis between the keratitis groups and the control group (p < 0.05). There was no significant differences between eyelid margin and conjunctiva samples in Alpha-Diversity analysis, but a significant difference between eyelid margin and corneal scraping samples in the keratitis group (p < 0.05, independent t-test). The abundances of Bacillus, Megamonas, Acinetobacter, and Rhodococcu were significantly elevated, while the abundance of Staphylococcus was decreased in the keratitis group compared to the control group. CONCLUSIONS The abundance of the ocular microbiome in patients with bacterial keratitis, fungal keratitis, or viral keratitis was significantly higher than those in the control group. Keratitis patients may have ecological disorder on ocular surface microbiome compared with controls. We believe that the conjunctiva and eyelid margin microbiome combined analysis can more comprehensively reflect the composition and abundance of ocular surface microbiome.
Collapse
Affiliation(s)
- Yan Cheng
- Department of Microbiology and Immunology, Key Laboratory of Environment and Genes Related to Diseases of Chinese Ministry of Education, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Na An
- The Fist Affiliated Hospital of Northwestern University, Department of Ophthalmology, The Xi'an Fist Hospital, Shaanxi Institute of Ophthalmology, China
| | - Hafiz Muhammad Ishaq
- Faculty of Veterinary and Animal Sciences, Muhammad Nawaz Shareef University of Agriculture Multan, Pakistan
| | - Jiru Xu
- Department of Microbiology and Immunology, Key Laboratory of Environment and Genes Related to Diseases of Chinese Ministry of Education, School of Medicine, Xi'an Jiaotong University, Xi'an, China.
| |
Collapse
|
4
|
Barrera B, Bustamante A, Marín-Cornuy M, Aguila-Torres P. Contact lenses and ocular dysbiosis, from the transitory to the pathological. ARCHIVOS DE LA SOCIEDAD ESPANOLA DE OFTALMOLOGIA 2023; 98:586-594. [PMID: 37648207 DOI: 10.1016/j.oftale.2023.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 07/19/2023] [Indexed: 09/01/2023]
Abstract
Normal ocular microbiota is composed of different Gram-negative and positive bacterial communities that act as commensals on the ocular surface. An imbalance in the homeostasis of the native species or dysbiosis triggers functional alterations that can eventually lead to ocular conditions, indicating the use of contact lenses as the most relevant predisposing factor. Through a bibliographic review that added scientific articles published between 2018 and 2022, the relationship between healthy ocular microbiota and dysbiosis associated with the use of contact lenses that trigger ocular conditions was analyzed. The ocular microbiota in healthy individuals is mainly composed of bacteria from the phyla: Proteobacteria, Actinobacteria and Firmicutes. These bacterial communities associated with the use of contact lenses develop dysbiosis, observing an increase in certain genera such as Staphylococcus spp. and Pseudomonas spp., which under normal conditions are commensals of the ocular surface, but as their abundance is increased, they condition the appearance of various ocular conditions such as corneal infiltrative events, bacterial keratitis and corneal ulcer. These pathologies tend to evolve rapidly, which, added to late detection and treatment, can lead to a poor visual prognosis. It is suggested that professionals in the ophthalmology area learn about the composition of the communities of microorganisms that make up this ocular microbiota, in order to correctly distinguish and identify the causative agent, thereby providing a adequate and effective treatment to the user.
Collapse
Affiliation(s)
- B Barrera
- Laboratorio de Microbiología Molecular, Escuela de Tecnología Médica, Universidad Austral de Chile, Puerto Montt, Chile
| | - A Bustamante
- Laboratorio de Microbiología Molecular, Escuela de Tecnología Médica, Universidad Austral de Chile, Puerto Montt, Chile
| | - M Marín-Cornuy
- Laboratorio de Microbiología Molecular, Escuela de Tecnología Médica, Universidad Austral de Chile, Puerto Montt, Chile
| | - P Aguila-Torres
- Laboratorio de Microbiología Molecular, Escuela de Tecnología Médica, Universidad Austral de Chile, Puerto Montt, Chile.
| |
Collapse
|
5
|
Ashby NS, Johnson TJ, Castillo-Ronquillo Y, Payne CJ, Davenport C, Hoopes PC, Moshirfar M. Cutibacterium (Formerly Propionibacterium ) acnes Keratitis: A Review. Eye Contact Lens 2023; 49:212-218. [PMID: 36888541 DOI: 10.1097/icl.0000000000000975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
ABSTRACT Infectious keratitis is a devastating cause of vision loss worldwide. Cutibacterium acnes ( C. acnes ), a commensal bacterium of the skin and ocular surface, is an underrecognized but important cause of bacterial keratitis. This review presents the most comprehensive and up-to-date information for clinicians regarding the risk factors, incidence, diagnosis, management, and prognosis of C. acnes keratitis (CAK). Risk factors are similar to those of general bacterial keratitis and include contact lens use, past ocular surgery, and trauma. The incidence of CAK may be approximately 10%, ranging from 5% to 25% in growth-positive cultures. Accurate diagnosis requires anaerobic blood agar and a long incubation period (≥7 days). Typical clinical presentation includes small (<2 mm) ulcerations with deep stromal infiltrate causing an anterior chamber cell reaction. Small, peripheral lesions are usually resolved, and patients recover a high visual acuity. Severe infections causing VA of 20/200 or worse are common and often do not significantly improve even after treatment. Vancomycin is considered the most potent antibiotic against CAK, although other antibiotics such as moxifloxacin and ceftazidime are more commonly used as first-line treatment.
Collapse
Affiliation(s)
- Nathaniel S Ashby
- Creighton University School of Medicine (N.S.A.), Omaha, NE; Spencer Fox Eccles School of Medicine at the University of Utah (T.J.J.), Salt Lake City, UT; Hoopes Vision Research Center (Y.C.-R., C.J.P., C.D., P.C.H., M.M.), Hoopes Vision, Draper, UT; Case Western Reserve University School of Medicine (C.J.P.), Cleveland, OH; John A. Moran Eye Center (M.M.), Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT; and Utah Lions Eye Bank (M.M.), Murray, UT
| | | | | | | | | | | | | |
Collapse
|
6
|
Roth M, Goerke P, Holtmann C, Frings A, MacKenzie CR, Geerling G. Spectrum and resistance in bacterial infections of the ocular surface in a German tertiary referral center 2009-2019. Graefes Arch Clin Exp Ophthalmol 2022; 260:3909-3917. [PMID: 35687174 PMCID: PMC9666293 DOI: 10.1007/s00417-022-05721-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 05/23/2022] [Accepted: 05/27/2022] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Aim of this study was to evaluate the frequencies, trends, and antibiotic resistance of bacteria collected from ocular surface or contact lens material in a German tertiary referral center from 2009 to 2019. METHODS Microbiological data from 2009 to 2019 was analyzed. Culture-dependent microbial identification and analysis of antibiotic sensitivity was completed by the Institute of Microbiology. Statistical analysis of age- and sex-specific differences as well as changes in the microbial spectrum and resistance over the study period was performed with GraphPad Prism 9.0 applying nonparametric tests (level of significance: p ≦ 0.05). RESULTS A total of 6361 specimens were analyzed. Positivity rate was 18.6%. Sixty-three percent (n = 680) of the bacterial isolates were derived from ocular surface and 37% (n = 399) from contact lens material. The ratio of gram-negative bacteria was significantly higher in contact lens material. Multiresistant bacteria showed a significant increase with patient age (p < 0.0001). An overall increase in resistance to levofloxacin (p = 0.0239) was detected. Only 2.4% and 3.1% isolates were resistant to a combination of moxifloxacin and gentamicin, respectively, levofloxacin and gentamicin. CONCLUSIONS The reported bacterial spectrum is similar to comparable centers. Our data show that it should not be assumed that the newest classes of antibiotics have the best efficacy or lowest resistance levels. In suspected bacterial conjunctivitis, we propose using gentamicin as first-line therapy. In therapy refractive cases and in involvement of the cornea, we recommend a combination of gentamicin and ofloxacin or moxifloxacin. Overall, the evaluated organisms showed good sensitivity to the regularly used antibiotics.
Collapse
Affiliation(s)
- Mathias Roth
- Department of Ophthalmology, Heinrich-Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany.
| | - Paul Goerke
- Department of Ophthalmology, Heinrich-Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Christoph Holtmann
- Department of Ophthalmology, Heinrich-Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Andreas Frings
- Department of Ophthalmology, Heinrich-Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Colin R MacKenzie
- Institute of Medical Microbiology and Hospital Hygiene of the University Hospital Duesseldorf, Duesseldorf, Germany
| | - Gerd Geerling
- Department of Ophthalmology, Heinrich-Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| |
Collapse
|
7
|
Cavuoto KM, Zhu AY. The Role of the Ocular Surface Microbiome (OSM) in Diseases of the Anterior Segment and Ocular Surface. CURRENT OPHTHALMOLOGY REPORTS 2022. [DOI: 10.1007/s40135-022-00294-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
8
|
Borroni D, Paytuví-Gallart A, Sanseverino W, Gómez-Huertas C, Bonci P, Romano V, Giannaccare G, Rechichi M, Meduri A, Oliverio GW, Rocha-de-Lossada C. Exploring the Healthy Eye Microbiota Niche in a Multicenter Study. Int J Mol Sci 2022; 23:ijms231810229. [PMID: 36142138 PMCID: PMC9499403 DOI: 10.3390/ijms231810229] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 12/16/2022] Open
Abstract
Purpose: This study aims to explore and characterize healthy eye microbiota. Methods: Healthy subjects older than 18 years were selected for this descriptive cross-sectional study. Samples were collected with an eSwab with 1 mL of Liquid Amies Medium (Copan Brescia, Italy). Following DNA extraction, libraries preparation, and amplification, PCR products were purified and end-repaired for barcode ligation. Libraries were pooled to a final concentration of 26 pM. Template preparation was performed with Ion Chef according to Ion 510, Ion 520, and Ion 530 Kit-Chef protocol. Sequencing of the amplicon libraries was carried out on a 520 or 530 chip using the Ion Torrent S5 system (Thermo Fisher; Waltham, MA, USA). Raw reads were analyzed with GAIA (v 2.02). Results: Healthy eye microbiota is a low-diversity microbiome. The vast majority of the 137 analyzed samples were highly enriched with Staphylococcus, whereas only in a few of them, other genera such as Bacillus, Pseudomonas, and Corynebacterium predominate. We found an average of 88 genera with an average Shannon index of 0.65. Conclusion: We identified nine different ECSTs. A better understanding of healthy eye microbiota has the potential to improve disease diagnosis and personalized regimens to promote health.
Collapse
Affiliation(s)
- Davide Borroni
- Department of Doctoral Studies, Riga Stradins University, LV-1007 Riga, Latvia
- Eyemetagenomics Ltd., 71–75, Shelton Street, Covent Garden, London WC2H 9JQ, UK
- Correspondence:
| | | | - Walter Sanseverino
- Sequentia Biotech SL, Carrer del Dr. Trueta, 179, 08005 Barcelona, Spain
| | - Carmen Gómez-Huertas
- Department of Ophthalmology, Hospital Universitario Virgen de las Nieves, 18014 Granada, Spain
| | - Paola Bonci
- Ospedale Civile di Ravenna, Banca Delle Cornee Della Regione Emilia-Romagna, 48121 Ravenna, Italy
| | - Vito Romano
- Department of Medical and Surgical Specialties, Radiological Specialties and Public Health, 9297 University of Brescia, ASST Spedali Civili, 25100 Brescia, Italy
| | - Giuseppe Giannaccare
- Department of Ophthalmology, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy
| | - Miguel Rechichi
- Centro Polispecialistico Mediterraneo, 88050 Sellia Marina, Italy
| | - Alessandro Meduri
- Biomedical Science Department, Institute of Ophthalmology, University of Messina, Via Consolare Valeria, 98146 Messina, Italy
| | - Giovanni William Oliverio
- Biomedical Science Department, Institute of Ophthalmology, University of Messina, Via Consolare Valeria, 98146 Messina, Italy
| | - Carlos Rocha-de-Lossada
- Eyemetagenomics Ltd., 71–75, Shelton Street, Covent Garden, London WC2H 9JQ, UK
- Department of Ophthalmology, Qvision (Vithas Almeria), 04120 Almería, Spain
- Hospital Regional Universitario de Malaga, 29010 Malaga, Spain
- Departamento de Cirugía, Área de Oftalmología, Universidad de Sevilla, 41004 Sevilla, Spain
| | | |
Collapse
|
9
|
Quorum quenching action of marine red alga Halemenia durvillei on biofilm forming Gram negative bacterial isolates from contact lens. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
10
|
Singh RB, Das S, Chodosh J, Sharma N, Zegans ME, Kowalski RP, Jhanji V. Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis. Prog Retin Eye Res 2021; 88:101028. [PMID: 34813978 DOI: 10.1016/j.preteyeres.2021.101028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 12/12/2022]
Abstract
Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the "anti-biotic era". Although, we are expeditiously developing our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins. In this review article, we have provided an overview of the established classical diagnostic techniques and therapeutics for keratitis caused by various bacteria. We have extensively reported our recent in-roads through novel tools for accurate diagnosis of mono- and poly-bacterial corneal infections. Furthermore, we outlined the recent progress by our group and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discussed in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.
Collapse
Affiliation(s)
- Rohan Bir Singh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Leiden University Medical Center, 2333, ZA Leiden, the Netherlands
| | - Sujata Das
- Cornea and Anterior Segment Services, LV Prasad Eye Institute, Bhubaneshwar, India
| | - James Chodosh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Namrata Sharma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Michael E Zegans
- Department of Ophthalmology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Regis P Kowalski
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| |
Collapse
|