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Somerville TF, Mdala S, Zungu T, Gandiwa M, Herbert R, Everett D, Corless CE, Beare NAV, Neal T, Horsburgh MJ, Darby A, Kaye SB, Kayange PC. Microbial keratitis in Southern Malawi: a microbiological pilot study. BMJ Open Ophthalmol 2024; 9:e001682. [PMID: 38653537 PMCID: PMC11043707 DOI: 10.1136/bmjophth-2024-001682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/10/2024] [Indexed: 04/25/2024] Open
Abstract
OBJECTIVE Microbial keratitis (MK) is a significant cause of blindness in sub-Saharan Africa. We investigated the feasibility of using a novel corneal impression membrane (CIM) for obtaining and processing samples by culture, PCR and whole-genome sequencing (WGS) in patients presenting with suspected MK in Malawi. METHODS AND ANALYSIS Samples were collected from patients presenting with suspected MK using a 12 mm diameter polytetrafluoroethylene CIM disc. Samples were processed using culture and PCR for Acanthamoeba, herpes simplex virus type 1 (HSV-1) and the bacterial 16S rRNA gene. Minimum inhibitory concentrations of isolates to eight antimicrobials were measured using susceptibility strips. WGS was used to characterise Staphylococcus aureus isolates. RESULTS 71 eyes of 71 patients were included. The overall CIM isolation rate was 81.7% (58 positive samples from 71 participants). 69 (81.2%) of isolates were Gram-positive cocci. Coagulase-negative Staphylococcus 31.8% and Streptococcus species 14.1% were the most isolated bacteria. Seven (9.9%) participants were positive for HSV-1. Fungi and Acanthamoeba were not detected. Moxifloxacin and chloramphenicol offered the best coverage for both Gram-positive and Gram-negative isolates when susceptibility was determined using known antimicrobial first quartile concentrations and European Committee on Antimicrobial Susceptibility Testing breakpoints, respectively. WGS identified known virulence genes associated with S. aureus keratitis. CONCLUSIONS In a resource-poor setting, a CIM can be used to safely sample the cornea in patients presenting with suspected MK, enabling identification of causative microorganisms by culture and PCR. Although the microbiological spectrum found was limited to the dry season, these preliminary results could be used to guide empirical treatment.
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Affiliation(s)
- Tobi F Somerville
- Department of Eye and Vision Sciences, University of Liverpool, Liverpool, UK
| | - Shaffi Mdala
- Queen Elizabeth Central Hospital, Blantyre, Southern Region, Malawi
- Ophthalmology Unit, Kamuzu University of Health Sciences, Blantyre, Southern Region, Malawi
| | - Thokozani Zungu
- Queen Elizabeth Central Hospital, Blantyre, Southern Region, Malawi
- Ophthalmology Unit, Kamuzu University of Health Sciences, Blantyre, Southern Region, Malawi
| | - Moira Gandiwa
- Ophthalmology Unit, Kamuzu University of Health Sciences, Blantyre, Southern Region, Malawi
- Kamuzu Central Hospital, Lilongwe, Central Region, Malawi
| | - Rose Herbert
- Department of Eye and Vision Sciences, University of Liverpool, Liverpool, UK
| | - Dean Everett
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- College of Medicine and Health Sciences, Infection Research Unit, Khalifa University, Abu Dhabi, UAE
| | - Caroline E Corless
- Medical Microbiology, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | | | - Timothy Neal
- Department of Infection and Immunity, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Malcolm J Horsburgh
- Department of Infection Biology and Microbiomes, University of Liverpool, Liverpool, UK
| | - Alistair Darby
- Department of Infection Biology and Microbiomes, University of Liverpool, Liverpool, UK
| | - Stephen B Kaye
- Department of Eye and Vision Sciences, University of Liverpool, Liverpool, UK
| | - Petros C Kayange
- Queen Elizabeth Central Hospital, Blantyre, Southern Region, Malawi
- Ophthalmology Unit, Kamuzu University of Health Sciences, Blantyre, Southern Region, Malawi
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Timsit S, Armand-Lefèvre L, Le Goff J, Salmona M. The clinical and epidemiological impacts of whole genomic sequencing on bacterial and virological agents. Infect Dis Now 2024; 54:104844. [PMID: 38101516 DOI: 10.1016/j.idnow.2023.104844] [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: 11/29/2023] [Accepted: 12/08/2023] [Indexed: 12/17/2023]
Abstract
Whole Genome Sequencing (WGS) is a molecular biology tool consisting in the sequencing of the entire genome of a given organism. Due to its ability to provide the finest available resolution of bacterial and virological genetics, it is used at several levels in the field of infectiology. On an individual scale and through application of a single technique, it enables the typological identification and characterization of strains, the characterization of plasmids, and enhanced search for resistance genes and virulence factors. On a collective scale, it enables the characterization of strains and the determination of phylogenetic links between different microorganisms during community outbreaks and healthcare-associated epidemics. The information provided by WGS enables real-time monitoring of strain-level epidemiology on a worldwide scale, and facilitates surveillance of the resistance dissemination and the introduction or emergence of pathogenic variants in humans or their environment. There are several possible approaches to completion of an entire genome. The choice of one method rather than another is essentially dictated by the matrix, either a clinical sample or a culture isolate, and the clinical objective. WGS is an advanced technology that remains costly despite a gradual decrease in its expenses, potentially hindering its implementation in certain laboratories and thus its use in routine microbiology. Even though WGS is making steady inroads as a reference method, efforts remain needed in view of so harmonizing its interpretations and decreasing the time to generation of conclusive results.
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Affiliation(s)
- Sarah Timsit
- Service de Virologie, Hôpital Saint-Louis, APHP, Paris, France; Service de Bactériologie, Hôpital Bichat-Claude Bernard, APHP, Paris, France
| | - Laurence Armand-Lefèvre
- Service de Bactériologie, Hôpital Bichat-Claude Bernard, APHP, Paris, France; IAME UMR 1137, INSERM, Université Paris Cité, Paris, France
| | - Jérôme Le Goff
- Service de Virologie, Hôpital Saint-Louis, APHP, Paris, France; INSERM U976, Insight Team, Université Paris Cité, Paris, France
| | - Maud Salmona
- Service de Virologie, Hôpital Saint-Louis, APHP, Paris, France; INSERM U976, Insight Team, Université Paris Cité, Paris, France.
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Guo X, Wang L, Zhang J, Liu Q, Wang B, Liu D, Gao F, Lanzi G, Zhao Y, Shi Y. Thwarting resistance: MgrA inhibition with methylophiopogonanone a unveils a new battlefront against S. aureus. NPJ Biofilms Microbiomes 2024; 10:15. [PMID: 38413623 PMCID: PMC10899606 DOI: 10.1038/s41522-024-00485-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 02/06/2024] [Indexed: 02/29/2024] Open
Abstract
Limitations in the clinical treatment of Staphylococcus aureus (S. aureus) infections have arisen due to the advent of antibiotic-resistant strains. Given the immense potential of therapeutic strategies targeting bacterial virulence, the role of MgrA as a pivotal virulence determinant in S. aureus-orchestrating resistance, adherence, and hundreds of virulence targets-becomes indispensable. In this investigation, leveraging advanced virtual screening and fluorescence anisotropy assays, we discerned methylophiopogonanone A (Mo-A), a flavonoid derivative, as a potent disruptor of the MgrA-DNA interaction nexus. Subsequent analysis revealed that Mo-A effectively inhibits the expression of virulence factors such as Hla and Pvl in S. aureus and markedly reduces its adhesion capability to fibrinogen. On a cellular landscape, Mo-A exerts a mitigating influence on the deleterious effects inflicted by S. aureus USA300 on A549 cells. Furthermore, our data indicate that Mo-A downregulates the transcription of genes associated with immune evasion, such as nucleases (nuc), Staphylococcal Chemotaxis Inhibitory Protein (chips), and Staphylococcal Complement Inhibitor (scin), thereby undermining immune escape and amplifying neutrophil chemotaxis. Upon application in an in vivo setting, Mo-A assumes a protective persona in a murine model of S. aureus USA300-induced pneumonia and demonstrates efficacy in the Galleria mellonella infection model. Of note, S. aureus displayed no swift acquisition of resistance to Mo-A, and the effect was synergistically enhanced when used in combination with vancomycin. Our findings add substantive weight to the expanding field of virulence-targeted therapeutic strategies and set the stage for more comprehensive exploration of Mo-A potential in combating antibiotic-resistant S. aureus.
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Affiliation(s)
- Xuerui Guo
- School of Pharmaceutical Science, Jilin University, Changchun, China
| | - Li Wang
- Clinical Medical College, Changchun University of Chinese Medicine, Changchun, China
| | - Jinlong Zhang
- School of Pharmaceutical Science, Jilin University, Changchun, China
| | - Quan Liu
- Center for Pathogen Biology and Infectious Diseases, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Bingmei Wang
- Clinical Medical College, Changchun University of Chinese Medicine, Changchun, China
| | - Da Liu
- School of Pharmacy, Changchun University of Chinese Medicine, Changchun, China
| | - Fei Gao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, China
| | | | - Yicheng Zhao
- Clinical Medical College, Changchun University of Chinese Medicine, Changchun, China.
- Center for Pathogen Biology and Infectious Diseases, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China.
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China.
| | - Yan Shi
- School of Pharmaceutical Science, Jilin University, Changchun, China.
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André C, Lebreton F, Van Tyne D, Cadorette J, Boody R, Gilmore MS, Bispo PJM. Microbiology of Eye Infections at the Massachusetts Eye and Ear: An 8-Year Retrospective Review Combined With Genomic Epidemiology. Am J Ophthalmol 2023; 255:43-56. [PMID: 37343741 PMCID: PMC10592486 DOI: 10.1016/j.ajo.2023.06.016] [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: 04/13/2023] [Revised: 05/28/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023]
Abstract
PURPOSE Ocular bacterial infections are important causes of morbidity and vision loss. Early antimicrobial therapy is necessary to save vision, but their efficacy is increasingly compromised by antimicrobial resistance (AMR). We assessed the etiology of ocular bacterial infections seen at Massachusetts Eye and Ear and investigated the molecular epidemiology and AMR profiles of contemporary isolates. DESIGN Laboratory investigation. METHODS We used a combination of phenotypic tests and genome sequencing to identify the predominant lineages of leading ocular pathogens and their AMR profiles. RESULTS A total of 1601 isolates were collected from 2014 to 2021, with Staphylococcus aureus (n = 621), coagulase-negative staphylococci (CoNS) (n = 234), Pseudomonas aeruginosa (n = 213), Enterobacteriaceae (n = 167), and Streptococcus pneumoniae (n = 95) being the most common. Resistance was high among staphylococci, with methicillin resistance (MR) detected in 28% of S aureus and 39.8% of CoNS isolates. Multidrug resistance (MDR) was frequent among MR staphylococci (MRSA 60%, MRCoNS 76.1%). The population of S aureus isolates consisted mainly of 2 clonal complexes (CCs): CC8 (26.1%) and CC5 (24.1%). CC5 strains carried a variety of AMR markers, resulting in high levels of resistance to first-line therapies. Similarly, the population of ocular Staphylococcus epidermidis was homogenous with most belonging to CC2 (85%), which were commonly MDR (48%). Conversely, ocular S pneumoniae, P aeruginosa, and Enterobacteriaceae were often susceptible to first-line therapies and grouped into highly diverse genetic populations. CONCLUSION Our data showed that ocular bacterial infections in our patient population are disproportionately caused by strains that are resistant to clinically relevant antibiotics and are associated with major epidemic genotypes with both community and hospital associations.
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Affiliation(s)
- Camille André
- From the Department of Ophthalmology (C.A., F.L., D.V., J.C., R.B., M.S.G., P.J.M.B.), Massachusetts Eye and Ear Infirmary
| | - François Lebreton
- From the Department of Ophthalmology (C.A., F.L., D.V., J.C., R.B., M.S.G., P.J.M.B.), Massachusetts Eye and Ear Infirmary; Department of Microbiology and Immunology (F.L., D.V., M.S.G.), Harvard Medical School, Boston, Massachusetts, USA
| | - Daria Van Tyne
- From the Department of Ophthalmology (C.A., F.L., D.V., J.C., R.B., M.S.G., P.J.M.B.), Massachusetts Eye and Ear Infirmary; Department of Microbiology and Immunology (F.L., D.V., M.S.G.), Harvard Medical School, Boston, Massachusetts, USA
| | - James Cadorette
- From the Department of Ophthalmology (C.A., F.L., D.V., J.C., R.B., M.S.G., P.J.M.B.), Massachusetts Eye and Ear Infirmary
| | - Rick Boody
- From the Department of Ophthalmology (C.A., F.L., D.V., J.C., R.B., M.S.G., P.J.M.B.), Massachusetts Eye and Ear Infirmary
| | - Michael S Gilmore
- From the Department of Ophthalmology (C.A., F.L., D.V., J.C., R.B., M.S.G., P.J.M.B.), Massachusetts Eye and Ear Infirmary; Department of Microbiology and Immunology (F.L., D.V., M.S.G.), Harvard Medical School, Boston, Massachusetts, USA
| | - Paulo J M Bispo
- From the Department of Ophthalmology (C.A., F.L., D.V., J.C., R.B., M.S.G., P.J.M.B.), Massachusetts Eye and Ear Infirmary.
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Patil R, Dehari D, Chaudhuri A, Kumar DN, Kumar D, Singh S, Nath G, Agrawal AK. Recent advancements in nanotechnology-based bacteriophage delivery strategies against bacterial ocular infections. Microbiol Res 2023; 273:127413. [PMID: 37216845 DOI: 10.1016/j.micres.2023.127413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/16/2023] [Accepted: 05/16/2023] [Indexed: 05/24/2023]
Abstract
Antibiotic resistance is growing as a critical challenge in a variety of disease conditions including ocular infections leading to disastrous effects on the human eyes. Staphylococcus aureus (S. aureus) mediated ocular infections are very common affecting different parts of the eye viz. vitreous chamber, conjunctiva, cornea, anterior and posterior chambers, tear duct, and eyelids. Blepharitis, dacryocystitis, conjunctivitis, keratitis, endophthalmitis, and orbital cellulitis are some of the commonly known ocular infections caused by S. aureus. Some of these infections are so fatal that they could cause bilateral blindness like panophthalmitis and orbital cellulitis, which is caused by methicillin-resistant S. aureus (MRSA) and vancomycin-resistance S. aureus (VRSA). The treatment of S. aureus infections with known antibiotics is becoming gradually difficult because of the development of resistance against multiple antibiotics. Apart from the different combinations and formulation strategies, bacteriophage therapy is growing as an effective alternative to treat such infections. Although the superiority of bacteriophage therapy is well established, yet physical factors (high temperatures, acidic pH, UV-rays, and ionic strength) and pharmaceutical barriers (poor stability, low in-vivo retention, controlled and targeted delivery, immune system neutralization, etc.) have the greatest influence on the viability of phage virions (also phage proteins). A variety of Nanotechnology based formulations such as polymeric nanoparticles, liposomes, dendrimers, nanoemulsions, and nanofibres have been recently reported to overcome the above-mentioned obstacles. In this review, we have compiled all these recent reports and discussed bacteriophage-based nanoformulations techniques for the successful treatment of ocular infections caused by multidrug-resistant S. aureus and other bacteria.
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Affiliation(s)
- Rohit Patil
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India
| | - Deepa Dehari
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India
| | - Aiswarya Chaudhuri
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India
| | - Dulla Naveen Kumar
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India
| | - Dinesh Kumar
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India
| | - Sanjay Singh
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India; Babasaheb Bhimrao Ambedkar University, Lucknow 226025, U.P., India
| | - Gopal Nath
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, U.P., India
| | - Ashish Kumar Agrawal
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India.
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Johnson WL, Sohn M, Woeller CF, Wozniak RAF. Staphylococcal Enterotoxins Promote Virulence in Bacterial Keratitis. Invest Ophthalmol Vis Sci 2023; 64:5. [PMID: 37133835 PMCID: PMC10166116 DOI: 10.1167/iovs.64.5.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
Purpose Staphylococcus aureus is an important cause of corneal infections (keratitis). To better understand the virulence mechanisms mediating keratitis, a recent comparative genomics study revealed that a set of secreted enterotoxins were found with higher prevalence among ocular versus non-ocular S. aureus clinical infection isolates, suggesting a key role for these toxins in keratitis. Although well known to cause toxic shock syndrome and S. aureus food poisoning, enterotoxins have not yet been shown to mediate virulence in keratitis. Methods A set of clinical isolate test strains, including a keratitis isolate that encodes five enterotoxins (sed, sej, sek, seq, ser), its corresponding enterotoxin deletion mutant and complementation strain, a keratitis isolate devoid of enterotoxins, and the non-ocular S. aureus strain USA300 along with its corresponding enterotoxin deletion and complementation strains, were evaluated for cellular adhesion, invasion and cytotoxicity in a primary corneal epithelial model as well as with microscopy. Additionally, strains were evaluated in an in vivo model of keratitis to quantify enterotoxin gene expression and measure disease severity. Results We demonstrate that, although enterotoxins do not impact bacterial adhesion or invasion, they do elicit direct cytotoxicity in vitro toward corneal epithelial cells. In an in vivo model, sed, sej, sek, seq, ser were found to have variable gene expression across 72 hours of infection and test strains encoding enterotoxins resulted in increased bacterial burden as well as a reduced host cytokine response. Conclusions Our results support a novel role for staphylococcal enterotoxins in promoting virulence in S. aureus keratitis.
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Affiliation(s)
- William L Johnson
- Department of Ophthalmology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States
| | - Michael Sohn
- Department of Biostatistics and Computational Biology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States
| | - Collynn F Woeller
- Department of Ophthalmology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States
| | - Rachel A F Wozniak
- Department of Ophthalmology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States
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Afzal M, Vijay AK, Stapleton F, Willcox MDP. Genomics of Staphylococcus aureus Strains Isolated from Infectious and Non-Infectious Ocular Conditions. Antibiotics (Basel) 2022; 11:antibiotics11081011. [PMID: 36009880 PMCID: PMC9405196 DOI: 10.3390/antibiotics11081011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 01/08/2023] Open
Abstract
Staphylococcus aureus is a major cause of ocular infectious (corneal infection or microbial keratitis (MK) and conjunctivitis) and non-infectious corneal infiltrative events (niCIE). Despite the significant morbidity associated with these conditions, there is very little data about specific virulence factors associated with the pathogenicity of ocular isolates. A set of 25 S. aureus infectious and niCIEs strains isolated from USA and Australia were selected for whole genome sequencing. Sequence types and clonal complexes of S. aureus strains were identified by using multi-locus sequence type (MLST). The presence or absence of 128 virulence genes was determined by using the virulence finder database (VFDB). Differences between infectious (MK + conjunctivitis) and niCIE isolates from USA and Australia for possession of virulence genes were assessed using the chi-square test. The most common sequence types found among ocular isolates were ST5, ST8 while the clonal complexes were CC30 and CC1. Virulence genes involved in adhesion (ebh, clfA, clfB, cna, sdrD, sdrE), immune evasion (chp, esaD, esaE, esxB, esxC, esxD), and serine protease enzymes (splA, splD, splE, splF) were more commonly observed in infectious strains (MK + conjunctivitis) than niCIE strains (p = 0.004). Toxin genes were present in half of infectious (49%, 25/51) and niCIE (51%, 26/51) strains. USA infectious isolates were significantly more likely to possess splC, yent1, set9, set11, set36, set38, set40, lukF-PV, and lukS-PV (p < 0.05) than Australian infectious isolates. MK USA strains were more likely to possesses yent1, set9, set11 than USA conjunctivitis strains (p = 0.04). Conversely USA conjunctivitis strains were more likely to possess set36 set38, set40, lukF-PV, lukS-PV (p = 0.03) than MK USA strains. The ocular strain set was then compared to 10 fully sequenced non-ocular S. aureus strains to identify differences between ocular and non-ocular isolates. Ocular isolates were significantly more likely to possess cna (p = 0.03), icaR (p = 0.01), sea (p = 0.001), set16 (p = 0.01), and set19 (p = 0.03). In contrast non-ocular isolates were more likely to possess icaD (p = 0.007), lukF-PV, lukS-PV (p = 0.01), selq (p = 0.01), set30 (p = 0.01), set32 (p = 0.02), and set36 (p = 0.02). The clones ST5, ST8, CC30, and CC1 among ocular isolates generally reflect circulating non-ocular pathogenic S. aureus strains. The higher rates of genes in infectious and ocular isolates suggest a potential role of these virulence factors in ocular diseases.
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Afzal M, Vijay AK, Stapleton F, Willcox M. Virulence Genes of Staphylococcus aureus Associated With Keratitis, Conjunctivitis, and Contact Lens-Associated Inflammation. Transl Vis Sci Technol 2022; 11:5. [PMID: 35802366 PMCID: PMC9279920 DOI: 10.1167/tvst.11.7.5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Purpose Staphylococcus aureus, cause a range of ocular diseases in humans, including noninfectious corneal infiltrative events (niCIE), infectious conjunctivitis and sight threatening microbial keratitis (MK). This study aimed to determine the possession of known virulence genes of S. aureus associated with MK and conjunctivitis, in strains isolated from these conditions and niCIE. Methods Sixty-three S. aureus strains—23 from MK, 26 from conjunctivitis, and 14 from niCIE—were evaluated for possession of genes. Polymerase chain reaction was used for the detection of mecA and 10 known virulence genes involved in MK (clfA, fnbpA, eap, coa, scpA, sspB, sspA, hla, hld, and hlg), 2 associated with conjunctivitis (pvl and seb). Results mecA was present in 35% of infections and 7% of niCIE strains (P = 0.05). It was not seen in infection strains from Australia. Adhesion genes were found in all strains except clfA, which was found in 75% of infection and 93% of niCIE strains. Invasion genes were found in higher frequency in infections strains—hlg (100% vs. 85%; P = 0.04) and hld (94% vs. 50%; P = 0.005)—compared with niCIE strains. Evasion genes were common in infection strains except scpA, which was found at a significantly higher frequency in niCIE strains (86%) compared with infection strains (45%; P = 0.001). Conclusions The higher rates of hlg and hld in strains isolated from infections than niCIE may have a role in pathogenesis, whereas scpA may be an important virulence factor during niCIEs. Translational Relevance This study has identified virulence factors involved in the ocular pathogenesis of S. aureus infections and niCIE.
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Affiliation(s)
- Madeeha Afzal
- School of Optometry and Vision Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Ajay Kumar Vijay
- School of Optometry and Vision Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Fiona Stapleton
- School of Optometry and Vision Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Mark Willcox
- School of Optometry and Vision Sciences, University of New South Wales, Sydney, NSW, Australia
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Neutralizing Staphylococcus aureus Virulence with AZD6389, a Three mAb Combination, Accelerates Closure of a Diabetic Polymicrobial Wound. mSphere 2022; 7:e0013022. [PMID: 35642538 PMCID: PMC9241520 DOI: 10.1128/msphere.00130-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Nonhealing diabetic foot ulcers (DFU), a major complication of diabetes, are associated with high morbidity and mortality despite current standard of care. Since Staphylococcus aureus is the most common pathogen isolated from nonhealing and infected DFU, we hypothesized that S. aureus virulence factors would damage tissue, promote immune evasion and alter the microbiome, leading to bacterial persistence and delayed wound healing. In a diabetic mouse polymicrobial wound model with S. aureus, Pseudomonas aeruginosa, and Streptococcus pyogenes, we report a rapid bacterial proliferation, prolonged pro-inflammatory response and large necrotic lesions unclosed for up to 40 days. Treatment with AZD6389, a three-monoclonal antibody combination targeting S. aureus alpha toxin, 4 secreted leukotoxins, and fibrinogen binding cell-surface adhesin clumping factor A resulted in full skin re-epithelization 21 days after inoculation. By neutralizing multiple virulence factors, AZD6389 effectively blocked bacterial agglutination and S. aureus-mediated cell killing, abrogated S. aureus-mediated immune evasion and targeted the bacteria for opsonophagocytic killing. Neutralizing S. aureus virulence not only facilitated S. aureus clearance in lesions, but also reduced S. pyogenes and P. aeruginosa numbers, damaging inflammatory mediators and markers for neutrophil extracellular trap formation 14 days post initiation. Collectively, our data suggest that AZD6389 holds promise as an immunotherapeutic approach against DFU complications. IMPORTANCE Diabetic foot ulcers (DFU) represent a major complication of diabetes and are associated with poor quality of life and increased morbidity and mortality despite standard of care. They have a complex pathogenesis starting with superficial skin lesions, which often progress to deeper tissue structures up to the bone and ultimately require limb amputation. The skin microbiome of diabetic patients has emerged as having an impact on DFU occurrence and chronicity. DFU are mostly polymicrobial, and the Gram-positive bacterium Staphylococcus aureus detected in more than 95% of cases. S. aureus possess a collection of virulence factors which participate in disease progression and may facilitate growth of other pathogens. Here we show in a diabetic mouse wound model that targeting some specific S. aureus virulence factors with a multimechanistic antibody combination accelerated wound closure and promoted full skin re-epithelization. This work opens promising new avenues for the treatment of DFU.
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Tuft S, Somerville TF, Li JPO, Neal T, De S, Horsburgh MJ, Fothergill JL, Foulkes D, Kaye S. Bacterial keratitis: identifying the areas of clinical uncertainty. Prog Retin Eye Res 2021; 89:101031. [PMID: 34915112 DOI: 10.1016/j.preteyeres.2021.101031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/24/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022]
Abstract
Bacterial keratitis is a common corneal infection that is treated with topical antimicrobials. By the time of presentation there may already be severe visual loss from corneal ulceration and opacity, which may persist despite treatment. There are significant differences in the associated risk factors and the bacterial isolates between high income and low- or middle-income countries, so that general management guidelines may not be appropriate. Although the diagnosis of bacterial keratitis may seem intuitive there are multiple uncertainties about the criteria that are used, which impacts the interpretation of investigations and recruitment to clinical studies. Importantly, the concept that bacterial keratitis can only be confirmed by culture ignores the approximately 50% of cases clinically consistent with bacterial keratitis in which investigations are negative. The aetiology of these culture-negative cases is unknown. Currently, the estimation of bacterial susceptibility to antimicrobials is based on data from systemic administration and achievable serum or tissue concentrations, rather than relevant corneal concentrations and biological activity in the cornea. The provision to the clinician of minimum inhibitory concentrations of the antimicrobials for the isolated bacteria would be an important step forward. An increase in the prevalence of antimicrobial resistance is a concern, but the effect this has on disease outcomes is yet unclear. Virulence factors are not routinely assessed although they may affect the pathogenicity of bacteria within species and affect outcomes. New technologies have been developed to detect and kill bacteria, and their application to bacterial keratitis is discussed. In this review we present the multiple areas of clinical uncertainty that hamper research and the clinical management of bacterial keratitis, and we address some of the assumptions and dogma that have become established in the literature.
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Affiliation(s)
- Stephen Tuft
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK.
| | - Tobi F Somerville
- Department of Eye and Vision Sciences, University of Liverpool, 6 West Derby Street, Liverpool, L7 8TX, UK.
| | - Ji-Peng Olivia Li
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK.
| | - Timothy Neal
- Department of Clinical Microbiology, Liverpool Clinical Laboratories, Liverpool University Hospital NHS Foundation Trust, Prescot Street, Liverpool, L7 8XP, UK.
| | - Surjo De
- Department of Clinical Microbiology, University College London Hospitals NHS Foundation Trust, 250 Euston Road, London, NW1 2PG, UK.
| | - Malcolm J Horsburgh
- Department of Infection and Microbiomes, University of Liverpool, Crown Street, Liverpool, L69 7BX, UK.
| | - Joanne L Fothergill
- Department of Eye and Vision Sciences, University of Liverpool, 6 West Derby Street, Liverpool, L7 8TX, UK.
| | - Daniel Foulkes
- Department of Eye and Vision Sciences, University of Liverpool, 6 West Derby Street, Liverpool, L7 8TX, UK.
| | - Stephen Kaye
- Department of Eye and Vision Sciences, University of Liverpool, 6 West Derby Street, Liverpool, L7 8TX, UK.
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Silva V, Ferreira E, Manageiro V, Reis L, Tejedor-Junco MT, Sampaio A, Capelo JL, Caniça M, Igrejas G, Poeta P. Distribution and Clonal Diversity of Staphylococcus aureus and Other Staphylococci in Surface Waters: Detection of ST425-t742 and ST130-t843 mecC-Positive MRSA Strains. Antibiotics (Basel) 2021; 10:antibiotics10111416. [PMID: 34827354 PMCID: PMC8614751 DOI: 10.3390/antibiotics10111416] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 02/07/2023] Open
Abstract
Natural aquatic environments represent one of the most important vehicles of bacterial dissemination. Therefore, we aimed to isolate staphylococci from surface waters and to investigate the presence of antimicrobial resistance genes and virulence factors as well as the genetic lineages of all Staphylococcus aureus isolates. Staphylococci were recovered from water samples collected from 78 surface waters, including rivers, streams, irrigation ditches, dams, lakes, and fountains. The presence of antimicrobial resistance genes and virulence factors was investigated by PCR. Multilocus sequence typing and spa-typing were performed in all S. aureus isolates. From the 78 water samples, 33 S. aureus, one S. pseudintermedius, and 51 coagulase-negative staphylococci (CoNS) were identified. Among the S. aureus isolates, four MRSA were identified, and all harbored the mecC gene. Fourteen S. aureus were susceptible to all antimicrobials tested and the remaining showed resistance to penicillin, erythromycin and/or tetracycline encoded by the blaZ, ermT, msr(A/B), tetL, and vgaA genes. Regarding the clonal lineages, one mecC-MRSA isolate belonged to spa-type t843 and sequence type (ST) 130 and the other three to t742 and ST425. The remaining S. aureus were ascribed 14 spa-types and 17 sequence types. Eleven species of CoNS were isolated: S. sciuri, S. lentus, S. xylosus, S. epidermidis, S. cohnii spp. urealyticus, S. vitulinus, S. caprae, S. carnosus spp. Carnosus, S. equorum, S. simulans, and S. succinus. Thirteen CoNS isolates had a multidrug resistance profile and carried the following genes: mecA, msr(A/B), mph(C), aph(3′)-IIIa, aac(6′)-Ie–aph(2′’)-Ia, dfrA, fusB, catpC221, and tetK. A high diversity of staphylococci was isolated from surface waters including mecCMRSA strains and isolates presenting multidrug-resistance profiles. Studies on the prevalence of antibiotic-resistant staphylococci in surface waters are still very scarce but extremely important to estimate the contribution of the aquatic environment in the spread of these bacteria.
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Affiliation(s)
- Vanessa Silva
- Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal;
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal;
- Functional Genomics and Proteomics Unit, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), University NOVA of Lisboa, 2825-466 Lisbon, Portugal
| | - Eugénia Ferreira
- National Reference Laboratory of Antibiotic Resistances and Healthcare Associated Infections (NRL-AMR/HAI), Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal; (E.F.); (V.M.); (L.R.); (M.C.)
- Centre for the Studies of Animal Science, Institute of Agrarian and Agri-Food Sciences and Technologies, Oporto University, 4051-401 Oporto, Portugal
| | - Vera Manageiro
- National Reference Laboratory of Antibiotic Resistances and Healthcare Associated Infections (NRL-AMR/HAI), Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal; (E.F.); (V.M.); (L.R.); (M.C.)
- Centre for the Studies of Animal Science, Institute of Agrarian and Agri-Food Sciences and Technologies, Oporto University, 4051-401 Oporto, Portugal
| | - Lígia Reis
- National Reference Laboratory of Antibiotic Resistances and Healthcare Associated Infections (NRL-AMR/HAI), Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal; (E.F.); (V.M.); (L.R.); (M.C.)
| | - María Teresa Tejedor-Junco
- Research Institute of Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, 35001 Canary Islands, Spain;
- Department of Clinical Sciences, University of Las Palmas de Gran Canaria, 35001 Canary Islands, Spain
| | - Ana Sampaio
- Department of Biology and Environment, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal;
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), UTAD, 5000-801 Vila Real, Portugal
| | - José Luis Capelo
- BIOSCOPE Group, LAQV@REQUIMTE, Chemistry Department, Faculty of Science and Technology, NOVA University of Lisbon, 2825-466 Almada, Portugal;
- Proteomass Scientific Society, 2825-466 Setubal, Portugal
| | - Manuela Caniça
- National Reference Laboratory of Antibiotic Resistances and Healthcare Associated Infections (NRL-AMR/HAI), Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal; (E.F.); (V.M.); (L.R.); (M.C.)
- Centre for the Studies of Animal Science, Institute of Agrarian and Agri-Food Sciences and Technologies, Oporto University, 4051-401 Oporto, Portugal
| | - Gilberto Igrejas
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal;
- Functional Genomics and Proteomics Unit, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), University NOVA of Lisboa, 2825-466 Lisbon, Portugal
| | - Patrícia Poeta
- Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal;
- Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), University NOVA of Lisboa, 2825-466 Lisbon, Portugal
- Correspondence: ; Tel.: +351-259350466
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Chen H, Gao H, Xie HT, Liu ST, Huang YK, Zhang MC. Hyperkeratinization and Proinflammatory Cytokine Expression in Meibomian Glands Induced by Staphylococcus aureus. Invest Ophthalmol Vis Sci 2021; 62:11. [PMID: 34643663 PMCID: PMC8525831 DOI: 10.1167/iovs.62.13.11] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 09/15/2021] [Indexed: 02/06/2023] Open
Abstract
Purpose This exploratory study aimed to investigate the morphological and pathological alterations of the meibomian gland (MG) with the Staphylococcus aureus crude extracts (SACEs) treatment. Methods Mouse MG explants were cultured and differentiated with or without SACEs for 48 hours. Explant's viability and cell death were determined by thiazolyl blue tetrazolium bromide (MTT) assay and TUNEL assay. MG morphology was observed by Hematoxylin and Eosin staining. Lipid droplet production was detected by Nile Red staining and LipidTox immunostaining. The pro-inflammatory cytokines were detected by ELISA. The relative gene and protein expression in MG explants was determined via quantitative RT-PCR, immunostaining, and immunoblotting. The components of the SACEs were analyzed by immunoblotting and silver staining. Results Our findings demonstrated that the SACEs treatment induced overexpression of keratin 1 (Krt1) in the ducts and acini of MG explants, accompanied by a decrease in viability and an increase in cell death in explants. Furthermore, the SACEs treatment dose-dependently increased the levels of TNF-α, IL-1β, and IL-6 in MG explants. The SACEs treatment induced activation of the nuclear factor kappa B (NF-κB) and AIM2 (absent in melanoma 2)/ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain) inflammasome signaling pathway in explants. Further investigation showed expression of the key adipogenesis-related molecule peroxisome proliferator-activated receptor γ was decreased after SACEs treatment. However, no change was found in the lipid synthesis of MG explants after treatment with the SACEs. Staphylococcal enterotoxins B (SEB) was detected in the SACEs. SEB induced the overexpression of Krt1 and IL-1β in ducts and acini of MG explants. Conclusions Our findings confirm that Staphylococcus aureus induced hyperkeratinization and pro-inflammatory cytokines expression in MG explants ducts and acini. These effects might be mediated by SEB. Activation of the NF-κB and AIM2/ASC signaling pathway is involved in this process.
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Affiliation(s)
- Hua Chen
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Gao
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hua-Tao Xie
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shu-Ting Liu
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu-Kan Huang
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ming-Chang Zhang
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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