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Etheridge T, Swiston C, Harrie RP, Bernstein PS. ACUTE POST-TRAUMATIC ENDOPHTHALMITIS SECONDARY TO BACILLUS PUMILUS / SAFENSIS. Retin Cases Brief Rep 2024; 18:305-307. [PMID: 36729827 DOI: 10.1097/icb.0000000000001391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 11/26/2022] [Indexed: 02/03/2023]
Abstract
PURPOSE To report a case of post-traumatic endophthalmitis secondary to Bacillus pumilus/safensis . METHODS Observational case report of a single patient. RESULTS A 62-year-old man presented with a traumatic corneal laceration because of baling wire while working on a sheep farm. Appropriate corneal laceration repair with injection of intravitreal antibiotics (ceftazidime, clindamycin, and vancomycin) was performed. A single organism, identified as B. pumilus or Bacillus safensis, was isolated from the vitreous aspirate. A subsequent pars plana vitrectomy, pars plana lensectomy, anterior capsulotomy, and fluid-air exchange was required because of severe inflammatory reaction from retained lens material, retinal edema, and vitreous opacities. Vision improved from hand motion to 20/60 at the three-month follow-up visit. CONCLUSION We describe a case of acute post-traumatic endophthalmitis secondary to B. pumilus/safensis.
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Affiliation(s)
- Tyler Etheridge
- John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
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2
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Coburn PS, Miller FC, LaGrow AL, Mursalin H, Gregory A, Parrott A, Astley D, Callegan MC. Virulence-related genotypic differences among Bacillus cereus ocular and gastrointestinal isolates and the relationship to endophthalmitis pathogenesis. Front Cell Infect Microbiol 2023; 13:1304677. [PMID: 38106476 PMCID: PMC10722173 DOI: 10.3389/fcimb.2023.1304677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/03/2023] [Indexed: 12/19/2023] Open
Abstract
Background Bacillus cereus (Bc) can cause self-limiting gastrointestinal infections, but when infecting the eye, can cause rapid and irreversible blindness. This study investigated whether clinical ocular and gastrointestinal Bc isolates differed in terms of virulence-related genotypes and endophthalmitis virulence. Methods Twenty-eight Bc ocular, gastrointestinal, and laboratory reference isolates were evaluated. Hemolysis assays were performed to assess potential differences in hemolytic activity. The presence of twenty Bc virulence-related genes was assessed by PCR. A subset of ocular and gastrointestinal isolates differing in PCR positivity for 5 virulence genes was compared to strain ATCC14579 in an experimental murine model of endophthalmitis. At 8 hours post infection, retinal function was evaluated by electroretinography, and intraocular bacterial concentrations were determined by plate counts. Results Gastrointestinal Bc isolates were more hemolytic than the Bc ocular isolates and ATCC14579 (p < 0.0001). Bc ocular isolates were more frequently PCR-positive for capK, cytK, hblA, hblC, and plcR compared to the gastrointestinal isolates (p ≤ 0.0002). In the endophthalmitis model, mean A-wave retention did not differ significantly between eyes infected with ATCC14579 and eyes infected with the selected ocular or gastrointestinal isolates (p ≥ 0.3528). Similar results were observed for mean B-wave retention (p ≥ 0.0640). Only one diarrheal isolate showed significantly greater B-wave retention when compared to ATCC14579 (p = 0.0303). No significant differences in mean A-wave (p ≥ 0.1535) or B-wave (p ≥ 0.0727) retention between the selected ocular and gastrointestinal isolates were observed. Intraocular concentrations of ATCC14579 were significantly higher than the selected ocular isolate and 3 of the gastrointestinal isolates (p ≤ 0.0303). Intraocular concentrations of the selected ocular isolate were not significantly different from the gastrointestinal isolates (p ≥ 0.1923). Conclusions Among the subset of virulence-related genes assessed, 5 were significantly enriched among the ocular isolates compared to gastrointestinal isolates. While hemolytic activity was higher among gastrointestinal isolates, retinal function retention and intraocular growth was not significantly different between the selected ocular and gastrointestinal isolates. These results suggest that Bc strains causing gastrointestinal infections, while differing from ocular isolates in hemolytic activity and virulence-related gene profile, are similarly virulent in endophthalmitis.
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Affiliation(s)
- Phillip S. Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Frederick C. Miller
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Department of Family and Preventive Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Austin L. LaGrow
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Huzzatul Mursalin
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Anna Gregory
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Aaron Parrott
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Daniel Astley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Michelle C. Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Dean McGee Eye Institute, Oklahoma City, OK, United States
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3
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Sun B, Lin S, Zheng M, Zheng B, Mao L, Gu Y, Cai J, Dai Y, Zheng M, Lou Y. Phosphatidylinositol-specific phospholipase C can decrease Müller cell viability and suppress its phagocytic activity by modulating PI3K/AKT signaling pathway. Can J Microbiol 2023; 69:501-511. [PMID: 37672795 DOI: 10.1139/cjm-2023-0044] [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] [Indexed: 09/08/2023]
Abstract
Bacillus cereus endophthalmitis is a devastating eye infection that causes rapid blindness through the release of extracellular tissue-destructive exotoxins. The phagocytic and antibacterial functions of ocular cells are the keys to limiting ocular bacterial infections. In a previous study, we identified a new virulence gene, plcA-2 (different from the original plcA-1 gene), that was strongly associated with the plcA gene of Listeria monocytogenes. This plcA gene had been confirmed to play an important role in phagocytosis. However, how the Bc-phosphatidylinositol-specific phospholipase C (PI-PLC) proteins encoded by the plcA-1/2 genes affect phagocytes remains unclear in B. cereus endophthalmitis. Here, we found that the enzymatic activity of Bc-PI-PLC-A2 was approximately twofold higher than that of Bc-PI-PLC-A1, and both proteins inhibited the viability of Müller cells. In addition, PI-PLC proteins reduced phagocytosis of Müller cells by decreasing the phosphorylation levels of key proteins in the PI3K/AKT signaling pathway. In conclusion, we showed that PI-PLC proteins contribute to inhibit the viability of and suppress the phagocytosis of Müller cells, providing new insights into the pathogenic mechanism of B. cereus endophthalmitis.
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Affiliation(s)
- Bianjin Sun
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Shudan Lin
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- Department of Clinical Laboratory, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou, China
| | - Mengmeng Zheng
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Beijia Zheng
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
- Department of Clinical Laboratory, Taizhou Central Hospital (Taizhou University Hospital), Taizhou, China
| | - Liping Mao
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Yunfeng Gu
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Jiabei Cai
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Yiran Dai
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Meiqin Zheng
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Yongliang Lou
- Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
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Durán-Manuel EM, Bello-López JM, Salinas-Bobadilla AD, Vargas-De-León C, Nieto-Velázquez NG, Moreno-Eutimio MA, Pastelin-Palacios R, Calzada-Mendoza CC, Blanco-Hernández DMR. Molecular Characterization of Bacterial Agents Causing External Ocular Infections Isolates of Patients in a Third Level Hospital. Pathogens 2023; 12:1294. [PMID: 38003759 PMCID: PMC10675722 DOI: 10.3390/pathogens12111294] [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: 10/02/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
Empirical use of antibiotics in the treatment of eye infections leads to bacterial pathogens becoming resistant to antibiotics; consequently, treatment failure and eye health complications occur. The aim of this study was to describe the phenotype and genotype of the resistance and adherence of bacterial agents causing eye infections in patients at Hospital Juárez de México. An observational, prospective, cross-sectional, and descriptive study was carried out in patients with signs and symptoms of ocular infection. Bacterial agents were isolated and identified by classical microbiology and mass spectrometry. Antibiotic resistance and adherence profiles were determined. Finally, resistance (mecA/SCCmec) and virulence (icaA and icaD) genes were detected in the Gram-positive population. The results showed that blepharitis was the most prevalent condition in the study population. A MALDI-TOF analysis revealed that Staphylococcus and Pseudomonas genus were the most prevalent as causal agents of infection. Resistances to β-lactams were detected of 44 to 100%, followed by clindamycins, aminoglycosides, folate inhibitors, and nitrofurans. A multiple correspondence analysis showed a relationship between mecA genotype and β-lactams resistance. The identification of SCCmecIII and SCCmecIV elements suggested community and hospital sources of infection. Finally, the coexistence of icaA+/icaD+/mecA(SCCmecIII) and icaA+/icaD+/mecA(SCCmecIV) genotypes was detected in S. aureus. The identification of resistant and virulent isolates highlights the importance of developing protocols that address the timely diagnosis of ocular infections. Herein, implications for the failure of antimicrobial therapy in the treatment of ocular infections in susceptible patients are analysed and discussed.
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Affiliation(s)
- Emilio Mariano Durán-Manuel
- Hospital Juárez de México, Mexico City 07760, Mexico
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | | | | | - Cruz Vargas-De-León
- Hospital Juárez de México, Mexico City 07760, Mexico
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | | | - Mario Adán Moreno-Eutimio
- Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510, Mexico
| | - Rodolfo Pastelin-Palacios
- Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, Mexico City 09230, Mexico
| | - Claudia Camelia Calzada-Mendoza
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico
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Mursalin MH, Astley R, Coburn PS, Bagaruka E, Hunt JJ, Fischetti VA, Callegan MC. Therapeutic potential of Bacillus phage lysin PlyB in ocular infections. mSphere 2023; 8:e0004423. [PMID: 37273201 PMCID: PMC10449515 DOI: 10.1128/msphere.00044-23] [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: 01/25/2023] [Accepted: 04/19/2023] [Indexed: 06/06/2023] Open
Abstract
Bacteriophage lytic enzymes (i.e., phage lysins) are a trending alternative for general antibiotics to combat growing antimicrobial resistance. Gram-positive Bacillus cereus causes one of the most severe forms of intraocular infection, often resulting in complete vision loss. It is an inherently β-lactamase-resistant organism that is highly inflammogenic in the eye, and antibiotics are not often beneficial as the sole therapeutic option for these blinding infections. The use of phage lysins as a treatment for B. cereus ocular infection has never been tested or reported. In this study, the phage lysin PlyB was tested in vitro, demonstrating rapid killing of vegetative B. cereus but not its spores. PlyB was also highly group specific and effectively killed the bacteria in various bacterial growth conditions, including ex vivo rabbit vitreous (Vit). Furthermore, PlyB demonstrated no cytotoxic or hemolytic activity toward human retinal cells or erythrocytes and did not trigger innate activation. In in vivo therapeutic experiments, PlyB was effective in killing B. cereus when administered intravitreally in an experimental endophthalmitis model and topically in an experimental keratitis model. In both models of ocular infection, the effective bactericidal property of PlyB prevented pathological damage to ocular tissues. Thus, PlyB was found to be safe and effective in killing B. cereus in the eye, greatly improving an otherwise devastating outcome. Overall, this study demonstrates that PlyB is a promising therapeutic option for B. cereus eye infections.IMPORTANCEEye infections from antibiotic-resistant Bacillus cereus are devastating and can result in blindness with few available treatment options. Bacteriophage lysins are an alternative to conventional antibiotics with the potential to control antibiotic-resistant bacteria. This study demonstrates that a lysin called PlyB can effectively kill B. cereus in two models of B. cereus eye infections, thus treating and preventing the blinding effects of these infections.
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Affiliation(s)
- Md Huzzatul Mursalin
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Roger Astley
- Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Phillip S. Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Eddy Bagaruka
- Oklahoma Christian University, Edmond, Oklahoma, USA
| | | | - Vincent A. Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, New York, USA
| | - Michelle C. Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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6
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Astley RA, Mursalin MH, Coburn PS, Livingston ET, Nightengale JW, Bagaruka E, Hunt JJ, Callegan MC. Ocular Bacterial Infections: A Ten-Year Survey and Review of Causative Organisms Based on the Oklahoma Experience. Microorganisms 2023; 11:1802. [PMID: 37512974 PMCID: PMC10386592 DOI: 10.3390/microorganisms11071802] [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: 05/24/2023] [Revised: 06/29/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
Ocular infections can be medical emergencies that result in permanent visual impairment or blindness and loss of quality of life. Bacteria are a major cause of ocular infections. Effective treatment of ocular infections requires knowledge of which bacteria are the likely cause of the infection. This survey of ocular bacterial isolates and review of ocular pathogens is based on a survey of a collection of isolates banked over a ten-year span at the Dean McGee Eye Institute in Oklahoma. These findings illustrate the diversity of bacteria isolated from the eye, ranging from common species to rare and unique species. At all sampled sites, staphylococci were the predominant bacteria isolated. Pseudomonads were the most common Gram-negative bacterial isolate, except in vitreous, where Serratia was the most common Gram-negative bacterial isolate. Here, we discuss the range of ocular infections that these species have been documented to cause and treatment options for these infections. Although a highly diverse spectrum of species has been isolated from the eye, the majority of infections are caused by Gram-positive species, and in most infections, empiric treatments are effective.
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Affiliation(s)
- Roger A Astley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Md Huzzatul Mursalin
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Phillip S Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Erin T Livingston
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - James W Nightengale
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Eddy Bagaruka
- Department of Biology, Oklahoma Christian University, Edmond, OK 73013, USA
| | - Jonathan J Hunt
- Department of Biology, Oklahoma Christian University, Edmond, OK 73013, USA
| | - Michelle C Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
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7
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Bacillus cereus Invasive Infections in Preterm Neonates: an Up-to-Date Review of the Literature. Clin Microbiol Rev 2022; 35:e0008821. [PMID: 35138121 PMCID: PMC8826972 DOI: 10.1128/cmr.00088-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus cereus group species are widespread, Gram-positive, spore-forming environmental bacteria. B. cereus sensu stricto is one of the major causes of food poisoning worldwide. In high-risk individuals, such as preterm neonates, B. cereus infections can cause fatal infections. It is important to note that the phenotypic identification methods commonly used in clinical microbiology laboratories make no distinction between B. cereus sensu stricto and the other members of the group (Bacillus anthracis excluded). As a result, all the invasive infections attributed to B. cereus are not necessarily due to B. cereus sensu stricto but likely to other closely related species of the B. cereus group. Next-generation sequencing (NGS) should be used to characterize the whole genome of the strains belonging to the B. cereus group. This could confirm whether the strains involved in previously reported B. cereus invasive infections preferentially belong to formerly known or emerging individual species. Moreover, infections related to B. cereus group species have probably been overlooked, since their isolation in human bacteriological samples has for a long time been regarded as an environmental contaminant of the cultures. Recent studies have questioned the emergence or reemergence of B. cereus invasive infections in preterm infants. This review reports our current understanding of B. cereus infections in neonates, including taxonomical updates, microbiological characteristics, bacterial identification, clinical features, host-pathogen interactions, environmental sources of contamination, and antimicrobial resistance.
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Vercruysse EM, Narinx FP, Rives ACM, Sauvage AC, Grauwels MF, Monclin SJ. Equine ulcerative keratitis in Belgium: Associated bacterial isolates and in vitro antimicrobial resistance in 200 eyes. Vet Ophthalmol 2022; 25:326-337. [PMID: 35343046 DOI: 10.1111/vop.12985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 03/02/2022] [Accepted: 03/13/2022] [Indexed: 01/10/2023]
Abstract
PURPOSE To describe bacterial isolates and associated antibiotic resistance from horses with ulcerative keratitis in Belgium. METHODS Medical records from horses with ulcerative keratitis presented to the ophthalmology service of the Veterinary teaching hospital of Liege, Belgium, between 2014 and 2021 were evaluated. Bacterial isolates were identified and VITEK® 2 (Biomérieux) provided antimicrobial susceptibility testing and resistance detection. RESULTS Two hundred eyes of 196 horses were sampled. Ninety-seven eyes had a positive bacterial culture (48.5%) and 139 bacterial isolates were identified. Staphylococcus (63/139: 45.3%) and Streptococcus (33/139: 23.7%) were the most frequent genus isolated. Staphylococcus aureus (21/139: 15.1%) was the most frequent species isolated of which half were methicillin-resistant (MRS). Streptococcus equi subsp. zooepidemicus (19/139: 13.7%) was the second most identified bacterial isolate. Only two Pseudomonas species were isolated (2/139: 1.4%). The overall resistance of all bacterial isolates against chloramphenicol (12.4%) and fluoroquinolones (14.3%) was low. Resistance against tobramycin, polymyxin B, gentamicin, fusidic acid, tetracycline, and neomycin ranged from 40.8% to 58.6%. When separating the MRS from the other staphylococci, a significant difference was noted in percentage of resistance to gentamicin (p = .00026) and tetracycline (p = .00015). MRS were highly resistant to gentamicin (75%) and tetracycline (100%), whereas the remaining staphylococci were significantly less resistant to gentamicin (17%) and tetracycline (40.4%). CONCLUSION Although Pseudomonas species has been rarely cultured, our results are roughly consistent with previous studies. Multiple drug resistance was high and resistance to first-choice antibiotics in ulcerative keratitis was noted. These results warrant continued monitoring of susceptibility profile.
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Affiliation(s)
- Eline M Vercruysse
- Ophthalmology Service, Veterinary Teaching Hospital, University of Liège, Liège, Belgium
| | - Florine P Narinx
- Ophthalmology Service, Veterinary Teaching Hospital, University of Liège, Liège, Belgium
| | - Albane C M Rives
- Department of Veterinary Management of Animal Resources, Veterinary Teaching Hospital, University of Liège, Liège, Belgium
| | - Aurélie C Sauvage
- Ophthalmology Service, Veterinary Teaching Hospital, University of Liège, Liège, Belgium
| | - Magda F Grauwels
- Ophthalmology Service, Veterinary Teaching Hospital, University of Liège, Liège, Belgium
| | - Sébastien J Monclin
- Ophthalmology Service, Veterinary Teaching Hospital, University of Liège, Liège, Belgium
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9
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Immune Inhibitor A Metalloproteases Contribute to Virulence in Bacillus Endophthalmitis. Infect Immun 2021; 89:e0020121. [PMID: 34097460 DOI: 10.1128/iai.00201-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Endophthalmitis is a devastating infection that can cause blindness. Over half of Bacillus endophthalmitis cases result in significant loss of useful vision. Bacillus produces many virulence factors that may contribute to retinal damage and robust inflammation. We analyzed Bacillus immune inhibitor A (InhA) metalloproteases in the context of this disease, hypothesizing that InhAs contribute to Bacillus intraocular virulence and inflammation. We analyzed phenotypes and infectivity of wild type (WT), InhA1-deficient (ΔinhA1), InhA2-deficient (ΔinhA2), or InhA1, A2, and A3-deficient (ΔinhA1-3) Bacillus thuringiensis. In vitro analysis of growth, proteolysis, and cytotoxicity were compared. WT and InhA mutants were similarly cytotoxic to retinal cells. Mutants ΔinhA1 and ΔinhA2 entered log phase growth earlier than WT. Proteolysis by the ΔinhA1-3 mutant was decreased, but this strain grew similar to WT in vitro. Experimental endophthalmitis was initiated by intravitreally infecting C57BL/6J mice with 200 CFU of B. thuringiensis WT or InhA mutants. Eyes were analyzed for intraocular Bacillus and myeloperoxidase concentrations, retinal function loss, and gross histological changes. Eyes infected with ΔinhA1 or ΔinhA2 strains contained greater numbers of bacteria than eyes infected with WT throughout the infection course. Eyes infected with single mutants had inflammation and retinal function loss similar to eyes infected with WT strain. Eyes infected with ΔinhA1-3 cleared the infection. RT-PCR results suggested that there may be compensatory expression of the other InhAs in the single InhA mutant. These results indicate that together, the InhA metalloproteases contribute to the severity of infection and inflammation in Bacillus endophthalmitis.
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10
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Coburn PS, Miller FC, Enty MA, Land C, LaGrow AL, Mursalin MH, Callegan MC. The Bacillus virulome in endophthalmitis. MICROBIOLOGY-SGM 2021; 167. [PMID: 34032564 DOI: 10.1099/mic.0.001057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Bacillus cereus is recognized as a causative agent of gastrointestinal syndromes, but can also cause a devastating form of intraocular infection known as endophthalmitis. We have previously reported that the PlcR/PapR master virulence factor regulator system regulates intraocular virulence, and that the S-layer protein (SlpA) contributes to the severity of B. cereus endophthalmitis. To better understand the role of other B. cereus virulence genes in endophthalmitis, expression of a subset of factors was measured at the midpoint of disease progression in a murine model of endophthalmitis by RNA-Seq. Several cytolytic toxins were expressed at significantly higher levels in vivo than in BHI. The virulence regulators codY, gntR, and nprR were also expressed in vivo. However, at this timepoint, plcR/papR was not detectable, although we previously reported that a B. cereus mutant deficient in PlcR was attenuated in the eye. The motility-related genes fla, fliF, and motB, and the chemotaxis-related gene cheA were detected during infection. We have shown previously that motility and chemotaxis phenotypes are important in B. cereus endophthalmitis. The sodA2 variant of manganese superoxide dismutase was the most highly expressed gene in vivo. Expression of the surface layer protein gene, slpA, an activator of Toll-like receptors (TLR)-2 and -4, was also detected during infection, albeit at low levels. Genes expressed in a mouse model of Bacillus endophthalmitis might play crucial roles in the unique virulence of B. cereus endophthalmitis, and serve as candidates for novel therapies designed to attenuate the severity of this often blinding infection.
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Affiliation(s)
- Phillip S Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Frederick C Miller
- Department of Family and Preventive Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Morgan A Enty
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Craig Land
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Austin L LaGrow
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Md Huzzatul Mursalin
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Michelle C Callegan
- Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA.,Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.,Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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11
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Mursalin MH, Coburn PS, Miller FC, Livingston ET, Astley R, Callegan MC. Innate Immune Interference Attenuates Inflammation In Bacillus Endophthalmitis. Invest Ophthalmol Vis Sci 2021; 61:17. [PMID: 33180117 PMCID: PMC7671874 DOI: 10.1167/iovs.61.13.17] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose To explore the consequences of innate interference on intraocular inflammatory responses during Bacillus endophthalmitis. Methods Bacillus endophthalmitis was induced in mice. Innate immune pathway activation was interfered by injecting S layer protein-deficient (∆slpA) B. thuringiensis or by treating wild-type (WT)–infected mice with a TLR2/4 inhibitor (WT+OxPAPC). At 10 hours postinfection, eyes were harvested and RNA was purified. A NanoString murine inflammation panel was used to compare gene expression in WT-infected, WT+OxPAPC, ∆slpA-infected, and uninfected eyes. Results In WT-infected eyes, 56% of genes were significantly upregulated compared to uninfected controls. Compared to WT-infected eyes, the expression of 27% and 50% of genes were significantly reduced in WT+OxPAPC and ∆slpA-infected eyes, respectively. Expression of 61 genes that were upregulated in WT-infected eyes was decreased in WT+OxPAPC and ∆slpA-infected eyes. Innate interference resulted in blunted expression of complement factors (C3, Cfb, and C6) and several innate pathway genes (TLRs 2, 4, 6, and 8, MyD88, Nod2, Nlrp3, NF-κB, STAT3, RelA, RelB, and Ptgs2). Innate interference also reduced the expression of several inflammatory cytokines (CSF2, CSF3, IL-6, IL-1β, IL-1α, TNFα, IL-23α, TGFβ1, and IL-12β) and chemokines (CCL2, CCL3, and CXCLs 1, 2, 3, 5, 9, and 10). All of the aforementioned genes were significantly upregulated in WT-infected eyes. Conclusions These results suggest that interfering with innate activation significantly reduced the intraocular inflammatory response in Bacillus endophthalmitis. This positive clinical outcome could be a strategy for anti-inflammatory therapy of an infection typically refractory to corticosteroid treatment.
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Affiliation(s)
- Md Huzzatul Mursalin
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States.,Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
| | - Phillip S Coburn
- Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States.,Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
| | - Frederick C Miller
- Department of Cell Biology and Department of Family and Preventive Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Erin T Livingston
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Roger Astley
- Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States.,Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
| | - Michelle C Callegan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States.,Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States.,Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
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Mursalin MH, Livingston E, Coburn PS, Miller FC, Astley R, Callegan MC. Intravitreal Injection and Quantitation of Infection Parameters in a Mouse Model of Bacterial Endophthalmitis. J Vis Exp 2021:10.3791/61749. [PMID: 33616100 PMCID: PMC8107885 DOI: 10.3791/61749] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Intraocular bacterial infections are a danger to the vision. Researchers use animal models to investigate the host and bacterial factors and immune response pathways associated with infection to identify viable therapeutic targets and to test drugs to prevent blindness. The intravitreal injection technique is used to inject organisms, drugs, or other substances directly into the vitreous cavity in the posterior segment of the eye. Here, we demonstrated this injection technique to initiate infection in the mouse eye and the technique of quantifying intraocular bacteria. Bacillus cereus was grown in brain heart infusion liquid media for 18 hours and resuspended to a concentration 100 colony forming units (CFU)/0.5 µL. A C57BL/6J mouse was anesthetized using a combination of ketamine and xylazine. Using a picoliter microinjector and glass capillary needles, 0.5 µL of the Bacillus suspension was injected into the mid vitreous of the mouse eye. The contralateral control eye was either injected with sterile media (surgical control) or was not injected (absolute control). At 10 hours post infection, mice were euthanized, and eyes were harvested using sterile surgical tweezers and placed into a tube containing 400 µL sterile PBS and 1 mm sterile glass beads. For ELISAs or myeloperoxidase assays, proteinase inhibitor was added to the tubes. For RNA extraction, the appropriate lysis buffer was added. Eyes were homogenized in a tissue homogenizer for 1-2 minutes. Homogenates were serially diluted 10-fold in PBS and track diluted onto agar plates. The remainder of the homogenates were stored at -80 °C for additional assays. Plates were incubated for 24 hours and CFU per eye was quantified. These techniques result in reproducible infections in mouse eyes and facilitate quantitation of viable bacteria, the host immune response, and omics of host and bacterial gene expression.
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Affiliation(s)
- Md Huzzatul Mursalin
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center; Department of Ophthalmology, Dean McGee Eye Institute
| | - Erin Livingston
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center
| | - Phillip S Coburn
- Department of Ophthalmology, Dean McGee Eye Institute; Dean McGee Eye Institute
| | - Frederick C Miller
- Department of Cell Biology and Department of Family and Preventive Medicine, University of Oklahoma Health Sciences Center
| | - Roger Astley
- Department of Ophthalmology, Dean McGee Eye Institute; Dean McGee Eye Institute
| | - Michelle C Callegan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center; Department of Ophthalmology, Dean McGee Eye Institute; Dean McGee Eye Institute;
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Coburn PS, Miller FC, Enty MA, Land C, LaGrow AL, Mursalin MH, Callegan MC. Expression of Bacillus cereus Virulence-Related Genes in an Ocular Infection-Related Environment. Microorganisms 2020; 8:microorganisms8040607. [PMID: 32331252 PMCID: PMC7232466 DOI: 10.3390/microorganisms8040607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 04/21/2020] [Indexed: 12/03/2022] Open
Abstract
Bacillus cereus produces many factors linked to pathogenesis and is recognized for causing gastrointestinal toxemia and infections. B. cereus also causes a fulminant and often blinding intraocular infection called endophthalmitis. We reported that the PlcR/PapR system regulates intraocular virulence, but the specific factors that contribute to B. cereus virulence in the eye remain elusive. Here, we compared gene expression in ex vivo vitreous humor with expression in Luria Bertani (LB) and Brain Heart Infusion (BHI) broth by RNA-Seq. The expression of several cytolytic toxins in vitreous was less than or similar to levels observed in BHI or LB. Regulators of virulence genes, including PlcR/PapR, were expressed in vitreous. PlcR/PapR was expressed at low levels, though we reported that PlcR-deficient B. cereus was attenuated in the eye. Chemotaxis and motility genes were expressed at similar levels in LB and BHI, but at low to undetectable levels in vitreous, although motility is an important phenotype for B. cereus in the eye. Superoxide dismutase, a potential inhibitor of neutrophil activity in the eye during infection, was the most highly expressed gene in vitreous. Genes previously reported to be important to intraocular virulence were expressed at low levels in vitreous under these conditions, possibly because in vivo cues are required for higher level expression. Genes expressed in vitreous may contribute to the unique virulence of B. cereus endophthalmitis, and future analysis of the B. cereus virulome in the eye will identify those expressed in vivo, which could potentially be targeted to arrest virulence.
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Affiliation(s)
- Phillip S. Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (M.A.E.); (C.L.); (A.L.L.); (M.C.C.)
- Correspondence:
| | - Frederick C. Miller
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
- Department of Family and Preventive Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Morgan A. Enty
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (M.A.E.); (C.L.); (A.L.L.); (M.C.C.)
| | - Craig Land
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (M.A.E.); (C.L.); (A.L.L.); (M.C.C.)
| | - Austin L. LaGrow
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (M.A.E.); (C.L.); (A.L.L.); (M.C.C.)
| | - Md Huzzatul Mursalin
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
| | - Michelle C. Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (M.A.E.); (C.L.); (A.L.L.); (M.C.C.)
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
- Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
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Mursalin MH, Coburn PS, Livingston E, Miller FC, Astley R, Flores-Mireles AL, Callegan MC. Bacillus S-Layer-Mediated Innate Interactions During Endophthalmitis. Front Immunol 2020; 11:215. [PMID: 32117322 PMCID: PMC7028758 DOI: 10.3389/fimmu.2020.00215] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 01/27/2020] [Indexed: 12/14/2022] Open
Abstract
Bacillus endophthalmitis is a severe intraocular infection. Hallmarks of Bacillus endophthalmitis include robust inflammation and rapid loss of vision. We reported that the absence of Bacillus surface layer protein (SLP) significantly blunted endophthalmitis severity. Here, we further investigated SLP in the context of Bacillus-retinal cell interactions and innate immune pathways to explore the mechanisms by which SLP contributes to intraocular inflammation. We compared phenotypes of Wild-type (WT) and SLP deficient (ΔslpA) Bacillus thuringiensis by analyzing bacterial adherence to and phagocytosis by human retinal Muller cells and phagocytosis by mouse neutrophils. Innate immune receptor activation by the Bacillus envelope and purified SLP was analyzed using TLR2/4 reporter cell lines. A synthetic TLR2/4 inhibitor was used as a control for this receptor activation. To induce endophthalmitis, mouse eyes were injected intravitreally with 100 CFU WT or ΔslpA B. thuringiensis. A group of WT infected mice was treated intravitreally with a TLR2/4 inhibitor at 4 h postinfection. At 10 h postinfection, infected eyes were analyzed for viable bacteria, inflammation, and retinal function. We observed that B. thuringiensis SLPs contributed to retinal Muller cell adherence, and protected this pathogen from Muller cell- and neutrophil-mediated phagocytosis. We found that B. thuringiensis envelope activated TLR2 and, surprisingly, TLR4, suggesting the presence of a surface-associated TLR4 agonist in Bacillus. Further investigation showed that purified SLP from B. thuringiensis activated TLR4, as well as TLR2 in vitro. Growth of WT B. thuringiensis was significantly higher and caused greater inflammation in untreated eyes than in eyes treated with the TLR2/4 inhibitor. Retinal function analysis also showed greater retention of A-wave and B-wave function in infected eyes treated with the TLR2/4 inhibitor. The TLR2/4 inhibitor was not antibacterial in vitro, and did not cause inflammation when injected into uninfected eyes. Taken together, these results suggest a potential role for Bacillus SLP in host-bacterial interactions, as well as in endophthalmitis pathogenesis via TLR2- and TLR4-mediated pathways.
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Affiliation(s)
- Md Huzzatul Mursalin
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Phillip S. Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Dean McGee Eye Institute, Oklahoma City, OK, United States
| | - Erin Livingston
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Frederick C. Miller
- Department of Cell Biology and Department of Family and Preventive Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Roger Astley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Dean McGee Eye Institute, Oklahoma City, OK, United States
| | - Ana L. Flores-Mireles
- Department of Biological Sciences, University of Notre Dame, South Bend, IN, United States
| | - Michelle C. Callegan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Dean McGee Eye Institute, Oklahoma City, OK, United States
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15
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The cereus matter of Bacillus endophthalmitis. Exp Eye Res 2020; 193:107959. [PMID: 32032628 DOI: 10.1016/j.exer.2020.107959] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/06/2020] [Accepted: 02/03/2020] [Indexed: 02/06/2023]
Abstract
Bacillus cereus (B. cereus) endophthalmitis is a devastating intraocular infection primarily associated with post-traumatic injuries. The majority of these infections result in substantial vision loss, if not loss of the eye itself, within 12-48 h. Multifactorial mechanisms that lead to the innate intraocular inflammatory response during this disease include the combination of robust bacterial replication, migration of the organism throughout the eye, and toxin production by the organism. Therefore, the window of therapeutic intervention in B. cereus endophthalmitis is quite narrow compared to that of other pathogens which cause this disease. Understanding the interaction of bacterial and host factors is critical in understanding the disease and formulating more rational therapeutics for salvaging vision. In this review, we will discuss clinical and research findings related to B. cereus endophthalmitis in terms of the organism's virulence and inflammogenic potential, and strategies for improving of current therapeutic regimens for this blinding disease.
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Molecular Signatures Related to the Virulence of Bacillus cereus Sensu Lato, a Leading Cause of Devastating Endophthalmitis. mSystems 2019; 4:4/6/e00745-19. [PMID: 31796569 PMCID: PMC6890933 DOI: 10.1128/msystems.00745-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus endophthalmitis is a devastating eye infection that causes rapid blindness through extracellular tissue-destructive exotoxins. Despite its importance, knowledge of the phylogenetic relationships and population structure of intraocular Bacillus spp. is lacking. In this study, we sequenced the whole genomes of eight Bacillus intraocular pathogens independently isolated from 8/52 patients with posttraumatic Bacillus endophthalmitis infections in the Eye Hospital of Wenzhou Medical University between January 2010 and December 2018. Phylogenetic analysis revealed that the pathogenic intraocular isolates belonged to Bacillus cereus, Bacillus thuringiensis and Bacillus toyonensis To determine the virulence of the ocular isolates, three representative strains were injected into mouse models, and severe endophthalmitis leading to blindness was observed. Through incorporating publicly available genomes for Bacillus spp., we found that the intraocular pathogens could be isolated independently but displayed a similar genetic context. In addition, our data provide genome-wide support for intraocular and gastrointestinal sources of Bacillus spp. belonging to different lineages. Importantly, we identified five molecular signatures of virulence and motility genes associated with intraocular infection, namely, plcA-2, InhA-3, InhA-4, hblA-5, and fliD using pangenome-wide association studies. The characterization of overrepresented genes in the intraocular isolates holds value to predict bacterial evolution and for the design of future intervention strategies in patients with endophthalmitis.IMPORTANCE In this study, we provided a detailed and comprehensive clinicopathological and pathogenic report of Bacillus endophthalmitis over the 8 years of the study period. We first reported the whole-genome sequence of Bacillus spp. causing devastating endophthalmitis and found that Bacillus toyonensis is able to cause endophthalmitis. Finally, we revealed significant endophthalmitis-associated virulence genes involved in hemolysis, immunity inhibition, and pathogenesis. Overall, as more sequencing data sets become available, these data will facilitate comparative research and will reveal the emergence of pathogenic "ocular bacteria."
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Livingston ET, Mursalin MH, Callegan MC. A Pyrrhic Victory: The PMN Response to Ocular Bacterial Infections. Microorganisms 2019; 7:microorganisms7110537. [PMID: 31703354 PMCID: PMC6920826 DOI: 10.3390/microorganisms7110537] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/03/2019] [Accepted: 11/05/2019] [Indexed: 12/21/2022] Open
Abstract
Some tissues of the eye are susceptible to damage due to their exposure to the outside environment and inability to regenerate. Immune privilege, although beneficial to the eye in terms of homeostasis and protection, can be harmful when breached or when an aberrant response occurs in the face of challenge. In this review, we highlight the role of the PMN (polymorphonuclear leukocyte) in different bacterial ocular infections that invade the immune privileged eye at the anterior and posterior segments: keratitis, conjunctivitis, uveitis, and endophthalmitis. Interestingly, the PMN response from the host seems to be necessary for pathogen clearance in ocular disease, but the inflammatory response can also be detrimental to vision retention. This “Pyrrhic Victory” scenario is explored in each type of ocular infection, with details on PMN recruitment and response at the site of ocular infection. In addition, we emphasize the differences in PMN responses between each ocular disease and its most common corresponding bacterial pathogen. The in vitro and animal models used to identify PMN responses, such as recruitment, phagocytosis, degranulation, and NETosis, are also outlined in each ocular infection. This detailed study of the ocular acute immune response to infection could provide novel therapeutic strategies for blinding diseases, provide more general information on ocular PMN responses, and reveal areas of bacterial ocular infection research that lack PMN response studies.
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Affiliation(s)
- Erin T. Livingston
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (E.T.L.); (M.H.M.)
| | - Md Huzzatul Mursalin
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (E.T.L.); (M.H.M.)
| | - Michelle C. Callegan
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (E.T.L.); (M.H.M.)
- Department of Ophthalmology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Oklahoma Center for Neuroscience, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
- Correspondence:
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Mursalin MH, Coburn PS, Livingston E, Miller FC, Astley R, Fouet A, Callegan MC. S-layer Impacts the Virulence of Bacillus in Endophthalmitis. Invest Ophthalmol Vis Sci 2019; 60:3727-3739. [PMID: 31479113 PMCID: PMC6719748 DOI: 10.1167/iovs.19-27453] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 07/19/2019] [Indexed: 02/07/2023] Open
Abstract
Purpose Bacillus causes a sight-threating infection of the posterior segment of the eye. The robust intraocular inflammatory response in this disease is likely activated via host innate receptor interactions with components of the Bacillus cell envelope. S-layer proteins (SLPs) of some Gram-positive pathogens contribute to the pathogenesis of certain infections. The potential contributions of SLPs in eye infection pathogenesis have not been considered. Here, we explored the role of a Bacillus SLP (SlpA) in endophthalmitis pathogenesis. Methods The phenotypes and infectivity of wild-type (WT) and S-layer deficient (ΔslpA) Bacillus thuringiensis were compared. Experimental endophthalmitis was induced in C57BL/6J mice by intravitreally injecting 100-CFU WT or ΔslpA B. thuringiensis. Infected eyes were analyzed by bacterial counts, retinal function analysis, histology, and inflammatory cell influx. SLP-induced inflammation was also analyzed in vitro. Muller cells (MIO-M1) were treated with purified SLP. Nuclear factor-κB (NF-κB) DNA binding was measured by ELISA and expression of proinflammatory mediators from Muller cells was measured by RT-qPCR. Results Tested phenotypes of WT and ΔslpA B. thuringiensis were similar, with the exception of absence of the S-layer in the ΔslpA mutant. Intraocular growth of WT and ΔslpA B. thuringiensis was also similar. However, eyes infected with the ΔslpA mutant had significantly reduced inflammatory cell influx, less inflammatory damage to the eyes, and significant retention of retinal function compared with WT-infected eyes. SLP was also a potent stimulator of the NF-κB pathway and induced the expression of proinflammatory mediators (IL6, TNFα, CCL2, and CXCL-1) in human retinal Muller cells. Conclusions Taken together, our results suggest that SlpA contributes to the pathogenesis of Bacillus endophthalmitis, potentially by triggering innate inflammatory pathways in the retina.
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Affiliation(s)
- Md Huzzatul Mursalin
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Phillip S. Coburn
- Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
- Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
| | - Erin Livingston
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Frederick C. Miller
- Department of Cell Biology and Department of Family and Preventive Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Roger Astley
- Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
- Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
| | - Agnès Fouet
- Institut Cochin INSERM U1016, Paris, France
- CNRS 8104, Paris, France
- University Paris Descartes, Paris, France
| | - Michelle C. Callegan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
- Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
- Dean McGee Eye Institute, Oklahoma City, Oklahoma, United States
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
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19
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Borgman CJ. Recurrent conjunctivitis secondary to Gram‐positive bacillus, Bacillus thuringiensis. Clin Exp Optom 2018. [DOI: 10.1111/cxo.12561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Peker E, Cagan E, Dogan M, Kilic A, Caksen H, Yesilmen O. Periorbital Cellulitis Caused by Bacillus Thuringiensis. Eur J Ophthalmol 2018; 20:243-5. [DOI: 10.1177/112067211002000139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Purpose Periorbital cellulitis is an inflammation of the lids and periorbital tissues without signs of true involvement such as proptosis or limitation of eye movement. Methods Bacillus thuringiensis is a Gram-positive, spore-forming soil bacterium with the ability to produce insecticidal crystal proteins. B thuringiensis is an extremely rare causative organism of orbital and periorbital infections. However, it was rarely seen isolated in pediatric cases with preseptal cellulites. Ocular infections of this bacteria quickly progress, within 12–48 hours from inoculation, leading to endophthalmitis or panophthalmitis and irreversible vision loss. Results Periorbital cellulitis should be recognized promptly and treated carefully. Hospitalization, prompt systemic antibiotic therapy, and careful monitoring for signs of sepsis and local invasion are critical. Conclusions We report a rare presentation of periorbital cellulitis caused by B thuringiensis.
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Affiliation(s)
- Erdal Peker
- Department of Pediatrics, Yuzuncu Yil University School of Medicine, Van
| | - Eren Cagan
- Department of Pediatrics, Yuzuncu Yil University School of Medicine, Van
| | - Murat Dogan
- Department of Pediatrics, Yuzuncu Yil University School of Medicine, Van
| | - Adil Kilic
- Department of Ophthalmology, Yuzuncu Yil University School of Medicine, Van - Turkey
| | - Huseyin Caksen
- Department of Pediatrics, Yuzuncu Yil University School of Medicine, Van
| | - Osman Yesilmen
- Department of Pediatrics, Yuzuncu Yil University School of Medicine, Van
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Teweldemedhin M, Gebreyesus H, Atsbaha AH, Asgedom SW, Saravanan M. Bacterial profile of ocular infections: a systematic review. BMC Ophthalmol 2017; 17:212. [PMID: 29178851 PMCID: PMC5702129 DOI: 10.1186/s12886-017-0612-2] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 11/16/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Bacteria are the major contributor of ocular infections worldwide. Ocular infections, if left untreated, can damage the structures of the eye with possible blindness and visual impairments. This work was aimed to review the bacterial profile of ocular infections. METHODS Literature search was made in different electronic databases; the review was systematically made to get concrete findings. RESULTS As far as this review, Staphylococcus aureus, Coagulase negative Staphylococci, Streptococcus pneumoniae and Pseudomonas aeruginosa are the leading isolates in ocular infections. Frequent pathogens of the respective clinical diagnose include Staphylococci, Streptococcus pyogenes and Pseudomonas aeruginosa in blepharitis; Staphylococci, Streptococus pneumoniae, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli in Conjunctivitis; Staphylococci, P. aeruginosa and E. coli in dacryocystitis; Coagulase negative Staphylococci, Pseudomonas aeruginosa and Staphylococcus aureus in keratitis; Streptococcus viridians, Streptococcus pneumoniae and Coagulase negative Staphylococci in endophthalmitis diagnoses. Endogenous endophthalmitis is associated with Klebsiella pneumoniae whereas Coagulase negative Staphylococci and Bacillus spp. are common causes of post-operative and post-traumatic endophthalmitis. However, the predominant pathogens may not be exactly same in all areas of the world, in the United States for instance, Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae are the major causes of conjunctivitis. CONCLUSION Gram positive bacteria are the major contributor of bacterial ocular infections. The distribution and proportion of bacterial isolates among clinical diagnoses varied but without exclusive anatomical restriction. To mitigate the burden of bacterial ocular infections, physicians should regard on risk reduction and comply with etiologic approach of diagnosis.
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Affiliation(s)
- Mebrahtu Teweldemedhin
- Department of Medical Laboratory Sciences, College of Health Sciences, Aksum University, Aksum, Tigray Ethiopia
| | - Hailay Gebreyesus
- Department of Public health, College of Health Sciences, Aksum University, Aksum, Tigray Ethiopia
| | | | - Solomon Weldegebreal Asgedom
- Department of Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Mekelle University, Mekelle, Tigray Ethiopia
| | - Muthupandian Saravanan
- Department of Medical Microbiology and Immunology, Institute of Biomedical Sciences, College of Health Sciences, Mekelle University, Mekelle, Tigray Ethiopia
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Abstract
Endophthalmitis is a severe eye infection that may result in permanent loss of useful vision in the affected eye. Most cases are exogenous and occur as a complication of cataract surgery, an intravitreal injection, or penetrating ocular trauma. Endogenous endophthalmitis results from hematogenous seeding of the eye by bacteria or fungi, but bacteremia or fungemia may be transient and patients may present without symptoms of systemic infection. Nearly all endophthalmitis patients present with decreased vision, and some also have eye pain. Eye examination usually reveals a hypopyon and intraocular inflammation. Diagnosis is clinical, supported by cultures of the vitreous and/or aqueous or by blood cultures in some endogenous cases. Molecular diagnostic techniques have been used in research laboratories for pathogen identification in endophthalmitis and offer the possibility of rapid diagnosis, including in culture-negative cases. Intravitreal injection of antibiotics is the most important component of treatment; some cases also benefit from surgical debridement of the vitreous by a vitrectomy. The visual outcome depends partly on the pathogen: coagulase-negative staphylococcal endophthalmitis has a better prognosis than does streptococcal endophthalmitis, for example. Endophthalmitis is a medical emergency, and prompt diagnosis and treatment are essential for saving vision.
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Affiliation(s)
- Marlene L Durand
- Departments of Medicine and Ophthalmology, Harvard Medical School, and Infectious Disease Service, Massachusetts Eye and Ear Infirmary, and Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
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Transferrin Impacts Bacillus thuringiensis Biofilm Levels. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3628268. [PMID: 28025643 PMCID: PMC5153491 DOI: 10.1155/2016/3628268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 11/07/2016] [Accepted: 11/08/2016] [Indexed: 01/17/2023]
Abstract
The present study examined the impact of transferrin on Bacillus thuringiensis biofilms. Three commercial strains, an environmental strain (33679), the type strain (10792), and an isolate from a diseased insect (700872), were cultured in iron restricted minimal medium. All strains produced biofilm when grown in vinyl plates at 30°C. B. thuringiensis 33679 had a biofilm biomass more than twice the concentration exhibited by the other strains. The addition of transferrin resulted in slightly increased growth yields for 2 of the 3 strains tested, including 33679. In contrast, the addition of 50 μg/mL of transferrin resulted in an 80% decrease in biofilm levels for strain 33679. When the growth temperature was increased to 37°C, the addition of 50 μg/mL of transferrin increased culture turbidity for only strain 33679. Biofilm levels were again decreased in strain 33679 at 37°C. Growth of B. thuringiensis cultures in polystyrene resulted in a decrease in overall growth yields at 30°C, with biofilm levels significantly decreased for 33679 in the presence of transferrin. These findings demonstrate that transferrin impacts biofilm formation in select strains of B. thuringiensis. Identification of these differences in biofilm regulation may be beneficial in elucidating potential virulence mechanisms among the differing strains.
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Parkunan SM, Randall CB, Astley RA, Furtado GC, Lira SA, Callegan MC. CXCL1, but not IL-6, significantly impacts intraocular inflammation during infection. J Leukoc Biol 2016; 100:1125-1134. [PMID: 27286792 DOI: 10.1189/jlb.3a0416-173r] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/26/2016] [Indexed: 12/24/2022] Open
Abstract
During intraocular bacterial infections, the primary innate responders are neutrophils, which may cause bystander damage to the retina or perturb the clarity of the visual axis. We hypothesized that cytokine IL-6 and chemokine CXCL1 contributed to rapid neutrophil recruitment during Bacillus cereus endophthalmitis, a severe form of intraocular infection that is characterized by explosive inflammation and retinal damage that often leads to rapid vision loss. To test this hypothesis, we compared endophthalmitis pathogenesis in C57BL/6J, IL-6-/-, and CXCL1-/- mice. Bacterial growth in eyes of CXCL1-/-, IL-6-/-, and C67BL/6J mice was similar. Retinal function retention was greater in eyes of IL-6-/- and CXCL1-/- mice compared with that of C57BL/6J, despite these eyes having similar bacterial burdens. Neutrophil influx into eyes of CXCL1-/- mice was reduced to a greater degree compared with that of eyes of IL6-/- mice. Histology confirmed significantly less inflammation in eyes of CXCL1-/- mice, but similar degrees of inflammation in IL6-/- and C57BL/6J eyes. Because inflammation was reduced in eyes of infected CXCL1-/- mice, we tested the efficacy of anti-CXCL1 in B. cereus endophthalmitis. Retinal function was retained to a greater degree and there was less overall inflammation in eyes treated with anti-CXCL1, which suggested that anti-CXCL1 may have therapeutic efficacy in limiting inflammation during B. cereus endophthalmitis. Taken together, our results indicate that absence of IL-6 did not affect overall pathogenesis of endophthalmitis. In contrast, absence of CXCL1, in CXCL1-/- mice or after anti-CXCL1 treatment, led to an improved clinical outcome. Our findings suggest a potential benefit in targeting CXCL1 to control inflammation during B. cereus and perhaps other types of intraocular infections.
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Affiliation(s)
- Salai Madhumathi Parkunan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - C Blake Randall
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Roger A Astley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Glaucia C Furtado
- Immunology Institute, Icahn School of Medicine, Mount Sinai, New York, New York, USA; and
| | - Sergio A Lira
- Immunology Institute, Icahn School of Medicine, Mount Sinai, New York, New York, USA; and
| | - Michelle C Callegan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; .,Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.,Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA
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Affiliation(s)
- Allison R McMullen
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Carey-Ann D Burnham
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
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Kroeger JK, Hassan K, Vörös A, Simm R, Saidijam M, Bettaney KE, Bechthold A, Paulsen IT, Henderson PJF, Kolstø AB. Bacillus cereus efflux protein BC3310 - a multidrug transporter of the unknown major facilitator family, UMF-2. Front Microbiol 2015; 6:1063. [PMID: 26528249 PMCID: PMC4601019 DOI: 10.3389/fmicb.2015.01063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/15/2015] [Indexed: 02/06/2023] Open
Abstract
Phylogenetic classification divides the major facilitator superfamily (MFS) into 82 families, including 25 families that are comprised of transporters with no characterized functions. This study describes functional data for BC3310 from Bacillus cereus ATCC 14579, a member of the “unknown major facilitator family-2” (UMF-2). BC3310 was shown to be a multidrug efflux pump conferring resistance to ethidium bromide, SDS and silver nitrate when heterologously expressed in Escherichia coli DH5α ΔacrAB. A conserved aspartate residue (D105) in putative transmembrane helix 4 was identified, which was essential for the energy dependent ethidium bromide efflux by BC3310. Transport proteins of the MFS comprise specific sequence motifs. Sequence analysis of UMF-2 proteins revealed that they carry a variant of the MFS motif A, which may be used as a marker to distinguish easily between this family and other MFS proteins. Genes orthologous to bc3310 are highly conserved within the B. cereus group of organisms and thus belong to the core genome, suggesting an important conserved functional role in the normal physiology of these bacteria.
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Affiliation(s)
- Jasmin K Kroeger
- Laboratory for Microbial Dynamics, Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo Oslo, Norway ; Institut für Pharmazeutische Biologie und Biotechnologie, Albert-Ludwigs Universität Freiburg, Germany
| | - Karl Hassan
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney NSW, Australia
| | - Aniko Vörös
- Laboratory for Microbial Dynamics, Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo Oslo, Norway
| | - Roger Simm
- Laboratory for Microbial Dynamics, Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo Oslo, Norway
| | - Massoud Saidijam
- School of BioMedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, UK
| | - Kim E Bettaney
- School of BioMedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, UK
| | - Andreas Bechthold
- Institut für Pharmazeutische Biologie und Biotechnologie, Albert-Ludwigs Universität Freiburg, Germany
| | - Ian T Paulsen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney NSW, Australia
| | - Peter J F Henderson
- School of BioMedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, UK
| | - Anne-Brit Kolstø
- Laboratory for Microbial Dynamics, Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo Oslo, Norway
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Pitt TL, McClure J, Parker MD, Amézquita A, McClure PJ. Bacillus cereus in personal care products: risk to consumers. Int J Cosmet Sci 2015; 37:165-74. [PMID: 25482451 DOI: 10.1111/ics.12191] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/27/2014] [Indexed: 12/17/2022]
Abstract
Bacillus cereus is ubiquitous in nature and thus occurs naturally in a wide range of raw materials and foodstuffs. B. cereus spores are resistant to desiccation and heat and able to survive dry storage and cooking. Vegetative cells produce several toxins which on ingestion in sufficient numbers can cause vomiting and/or diarrhoea depending on the toxins produced. Gastrointestinal disease is commonly associated with reheated or inadequately cooked foods. In addition to being a rare cause of several acute infections (e.g. pneumonia and septicaemia), B. cereus can also cause localized infection of post-surgical or trauma wounds and is a rare but significant pathogen of the eye where it may result in severe endophthalmitis often leading to loss of vision. Key risk factors in such cases are trauma to the eye and retained contaminated intraocular foreign bodies. In addition, rare cases of B. cereus-associated keratitis (inflammation of the cornea) have been linked to contact lens use. Bacillus cereus is therefore a microbial contaminant that could adversely affect product safety of cosmetic and facial toiletries and pose a threat to the user if other key risk factors are also present. The infective dose in the human eye is unknown, but as few as 100 cfu has been reported to initiate infection in a susceptible animal model. However, we are not aware of any reports in the literature of B. cereus infections in any body site linked with use of personal care products. Low levels of B. cereus spores may on occasion be present in near-eye cosmetics, and these products have been used by consumers for many years. In addition, exposure to B. cereus is more likely to occur through other routes (e.g. dustborne contamination) due to its ubiquity and resistance properties of spores. The organism has been recovered from the eyes of healthy individuals. Therefore, although there may be a perceived hazard, the risk of severe eye infections as a consequence of exposure through contaminated near-eye cosmetics is judged to be vanishingly small. It is unlikely that more stringent microbiological standards for near-eye cosmetics will have any impact on the risk of severe eye infections caused by B. cereus, as these are not linked to use of personal care products.
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Affiliation(s)
- T L Pitt
- 712 Kenton Lane, Harrow, Middlesex, HA3 6AB, UK
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Celandroni F, Salvetti S, Senesi S, Ghelardi E. Bacillus thuringiensis membrane-damaging toxins acting on mammalian cells. FEMS Microbiol Lett 2014; 361:95-103. [PMID: 25283838 DOI: 10.1111/1574-6968.12615] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 01/20/2023] Open
Abstract
Bacillus thuringiensis is widely used as a biopesticide in forestry and agriculture, being able to produce potent species-specific insecticidal toxins and considered nonpathogenic to other animals. More recently, however, repeated observations are documenting the association of this microorganism with various infectious diseases in humans, such as food-poisoning-associated diarrheas, periodontitis, bacteremia, as well as ocular, burn, and wound infections. Similar to B. cereus, B. thuringiensis produces an array of virulence factors acting against mammalian cells, such as phosphatidylcholine- and phosphatidylinositol-specific phospholipase C (PC-PLC and PI-PLC), hemolysins, in particular hemolysin BL (HBL), and various enterotoxins. The contribution of some of these toxins to B. thuringiensis pathogenicity has been studied in animal models of infection, following intravitreous, intranasal, or intratracheal inoculation. These studies lead to the speculation that the activities of PC-PLC, PI-PLC, and HBL are responsible for most of the pathogenic properties of B. thuringiensis in nongastrointestinal infections in mammals. This review summarizes data regarding the biological activity, the genetic basis, and the structural features of these membrane-damaging toxins.
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Affiliation(s)
- Francesco Celandroni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
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29
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Tran SL, Ramarao N. Bacillus cereus immune escape: a journey within macrophages. FEMS Microbiol Lett 2013; 347:1-6. [PMID: 23827020 DOI: 10.1111/1574-6968.12209] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 06/28/2013] [Indexed: 12/14/2022] Open
Abstract
During bacterial infection, professional phagocytes are attracted to the site of infection, where they constitute a first line of host cell defense. Their function is to engulf and destroy the pathogens. Thus, bacteria must withstand the bactericidal activity of professional phagocytes, including macrophages to counteract the host immune system. Bacillus cereus infections are characterized by bacteremia despite the accumulation of inflammatory cells at the site of infection. This implies that the bacteria have developed means of resisting the host immune system. Bacillus cereus spores survive, germinate, and multiply in contact with macrophages, eventually producing toxins that kill these cells. However, the exact mechanism by which B. cereus evades immune attack remains unclear. This review addresses the interaction between B. cereus and macrophages, highlighting, in particular, the ways in which the bacteria escape the microbicidal activities of professional phagocytes.
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Affiliation(s)
- Seav-Ly Tran
- INRA, Unité MICALIS, AgroParisTech, UMR-1319, La Minière, Guyancourt, France
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30
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Ehling-Schulz M, Messelhäusser U. Bacillus "next generation" diagnostics: moving from detection toward subtyping and risk-related strain profiling. Front Microbiol 2013; 4:32. [PMID: 23440299 PMCID: PMC3579190 DOI: 10.3389/fmicb.2013.00032] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 02/05/2013] [Indexed: 11/29/2022] Open
Abstract
The highly heterogeneous genus Bacillus comprises the largest species group of endospore forming bacteria. Because of their ubiquitous nature, Bacillus spores can enter food production at several stages resulting in significant economic losses and posing a potential risk to consumers due the capacity of certain Bacillus strains for toxin production. In the past, food microbiological diagnostics was focused on the determination of species using conventional culture-based methods, which are still widely used. However, due to the extreme intra-species diversity found in the genus Bacillus, DNA-based identification and typing methods are gaining increasing importance in routine diagnostics. Several studies showed that certain characteristics are rather strain-dependent than species-specific. Therefore, the challenge for current and future Bacillus diagnostics is not only the efficient and accurate identification on species level but also the development of rapid methods to identify strains with specific characteristics (such as stress resistance or spoilage potential), trace contamination sources, and last but not least discriminate potential hazardous strains from non-toxic strains.
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Affiliation(s)
- Monika Ehling-Schulz
- Institute of Functional Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna Vienna, Austria
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31
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Ahmed Y, Pathengay A, Flynn HW, Isom R. Delayed-onset endophthalmitis associated with Ex-PRESS mini glaucoma shunt®. Ophthalmic Surg Lasers Imaging Retina 2012; 43 Online:e62-3. [PMID: 22785601 DOI: 10.3928/15428877-20120705-01] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 05/29/2012] [Indexed: 11/20/2022]
Abstract
The authors describe a 92-year-old man who developed delayed-onset endophthalmitis secondary to Bacillus sp. in his left eye 3 years after placement of an Ex-PRESS mini glaucoma shunt (Optonol Ltd., Neve Ilan, Israel). Seidel testing was positive over the Ex-PRESS mini glaucoma shunt. The patient underwent vitreous tap followed by intravitreal injections of vancomycin (1 mg/0.1 mL), ceftazadime (2.25 mg/0.1 mL), and dexamethasone (0.4 mg/0.1 mL), along with subconjunctival injection of vancomycin and tobramycin. The last recorded visual acuity was 3/200 in the left eye. With a 1-month follow-up, this case illustrates successful treatment with a vitreous tap and injection of intravitreal antibiotics. Vitrectomy and removal of the Ex-PRESS mini glaucoma shunt were not performed.
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Affiliation(s)
- Yasir Ahmed
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, Florida, USA
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Abstract
PURPOSE To evaluate the efficacy of vitrectomy with vancomycin for the treatment of experimental Bacillus cereus endophthalmitis. METHODS Endophthalmitis was initiated in rabbits via intravitreal injection of 100 colony-forming unit B. cereus. Treatment groups included 25-gauge transconjunctival sutureless vitrectomy with intravitreal vancomycin (1 mg) or vancomycin alone. Groups were treated at 4, 5, or 6 hours after infection. At 48 hours (for 4-hour and 5-hour groups) or 36 hours (for the 6-hour group) after infection, eyes were analyzed by electroretinography, histology, and inflammatory cell counts. RESULTS Treatment with vitrectomy/vancomycin at 4 hours resulted in significantly greater retinal function compared with that of vancomycin alone. Intraocular inflammation after treatment at 4 hours was minimal for both the treatment groups. Treatment with vitrectomy/vancomycin or vancomycin alone at 5 hours or 6 hours after infection resulted in similar levels of retinal function loss (i.e., >90%) and significant intraocular inflammation. CONCLUSION These results demonstrate that vitrectomy may be of therapeutic benefit in the treatment of B. cereus endophthalmitis but only during the early stages of infection.
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Shamsuddin N, Kumar A. TLR2 mediates the innate response of retinal Muller glia to Staphylococcus aureus. THE JOURNAL OF IMMUNOLOGY 2011; 186:7089-97. [PMID: 21602496 DOI: 10.4049/jimmunol.1100565] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Muller cells, the principal glia of the retina, play several key roles in normal and various retinal diseases. To date, their direct involvement in retinal innate defense against bacterial pathogens has not been investigated. In this article, we show that Muller cells express TLR2, a key sensor implicated in recognizing Gram-positive bacteria. We found that intravitreal injection of TLR2 agonist Pam3Cys and Staphylococcus aureus activated Muller glia in C57BL/6 mouse retina. Similarly, Pam3Cys or S. aureus elicited the expression of TLR2 and activated the NF-κB and p38 MAPK signaling cascade. Concomitant with the activation of signaling pathways, transcriptional expression and secretion of various proinflammatory cytokines (IL-6, TNF-α, and IL-1β), chemokines (IL-8), and antimicrobial peptide (LL-37) were also induced in Muller glia. Importantly, the culture media derived from TLR2-activated Muller glia exhibited robust bactericidal activity against S. aureus. Furthermore, use of neutralizing Ab, small interfering RNA, and pharmacological inhibitors revealed that Muller glial innate response to S. aureus is mediated via the TLR2-NF-κB axis. Collectively, this study for the first time, to our knowledge, establishes that the retinal Muller glia senses pathogens via TLR2 and contributes directly to retinal innate defense via production of inflammatory mediators and antimicrobial peptides.
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Affiliation(s)
- Nazeem Shamsuddin
- Department of Ophthalmology, Kresge Eye Institute, Wayne State University, Detroit, MI 48201, USA
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Fangio MF, Roura SI, Fritz R. Isolation and identification of Bacillus spp. and related genera from different starchy foods. J Food Sci 2010; 75:M218-21. [PMID: 20546413 DOI: 10.1111/j.1750-3841.2010.01566.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
UNLABELLED Samples of butternut squash, potatoes, rice, and wheat flour were analyzed. Bacillus spp. and related species belonging to Paenibacillus and Brevibacillus genera were found in 96% of the samples. In butternut squash, predominant species were Bacillus pumilus and Paenibacillus polymyxa together with other Bacillus spp. species (B. cereus, B. licheniformis, B. sphaericus, and B. subtilis). In all the potato samples, Bacillus species were detected (B. cereus, B. mycoides, and B. licheniformis). Also, Bacillus spp. were detected in 100% of the unhusked rice samples, while incidence in white rice samples was 83%. In total rice samples, B. pumilus, Brevibacillus brevis, and Paenibacillus macerans were the main species and B. cereus, P. polymyxa, B. subtilis, and Brevibacillus laterosporus had the lower percentage. The most important species found in wheat flour was P. polymyxa with colony forming units per gram of about 10(2). As the identified species were potentially causatives of foodborne diseases, attention should be given to sanitary and temperature conditions as critical factors that influence the safety and shelf life of these products. PRACTICAL APPLICATION Foodborne illness produce by B. cereus have been associated with a wide variety of food. In addition, some other Bacillus species have been related to foodborne disease in humans. Information about the virulence mechanisms of other Bacillus spp. is scanty and their risk is underestimated. Identifying the group of food and the food processes in which Bacillus cereus or other Bacillus spp. would be hazardous for human health is vital for the prevention of foodborne outbreak. In this study, we determined the incidence of Bacillus spp. and related genera in some food items of agriculture origin from Argentina. This research is relevant to identify the presence of potentially pathogen Bacillus species and related genera in this type of food.
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Mallozzi M, Viswanathan VK, Vedantam G. Spore-forming Bacilli and Clostridia in human disease. Future Microbiol 2010; 5:1109-23. [DOI: 10.2217/fmb.10.60] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Many Gram-positive spore-forming bacteria in the Firmicute phylum are important members of the human commensal microbiota, which, in rare cases, cause opportunistic infections. Other spore-formers, however, have evolved to become dedicated pathogens that can cause a striking variety of diseases. Despite variations in disease presentation, the etiologic agent is often the spore, with bacterially produced toxins playing a central role in the pathophysiology of infection. This review will focus on the specific diseases caused by spores of the Clostridia and Bacilli.
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Affiliation(s)
- Michael Mallozzi
- Department of Veterinary Science and Microbiology, University of Arizona, 1117, East Lowell St., Building 90, Room 303, Tucson, AZ 85721, USA
| | - VK Viswanathan
- Department of Veterinary Science and Microbiology, University of Arizona, 1117, East Lowell St., Building 90, Room 303, Tucson, AZ 85721, USA
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Abstract
Bacillus cereus is a Gram-positive aerobic or facultatively anaerobic, motile, spore-forming, rod-shaped bacterium that is widely distributed environmentally. While B. cereus is associated mainly with food poisoning, it is being increasingly reported to be a cause of serious and potentially fatal non-gastrointestinal-tract infections. The pathogenicity of B. cereus, whether intestinal or nonintestinal, is intimately associated with the production of tissue-destructive exoenzymes. Among these secreted toxins are four hemolysins, three distinct phospholipases, an emesis-inducing toxin, and proteases. The major hurdle in evaluating B. cereus when isolated from a clinical specimen is overcoming its stigma as an insignificant contaminant. Outside its notoriety in association with food poisoning and severe eye infections, this bacterium has been incriminated in a multitude of other clinical conditions such as anthrax-like progressive pneumonia, fulminant sepsis, and devastating central nervous system infections, particularly in immunosuppressed individuals, intravenous drug abusers, and neonates. Its role in nosocomial acquired bacteremia and wound infections in postsurgical patients has also been well defined, especially when intravascular devices such as catheters are inserted. Primary cutaneous infections mimicking clostridial gas gangrene induced subsequent to trauma have also been well documented. B. cereus produces a potent beta-lactamase conferring marked resistance to beta-lactam antibiotics. Antimicrobials noted to be effective in the empirical management of a B. cereus infection while awaiting antimicrobial susceptibility results for the isolate include ciprofloxacin and vancomycin.
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Affiliation(s)
- Edward J Bottone
- Division of Infectious Diseases, Box 1090, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
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The maintenance of the list of QPS microorganisms intentionally added to food or feed - Scientific Opinion of the Panel on Biological Hazards. EFSA J 2008. [DOI: 10.2903/j.efsa.2008.923] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Wiskur BJ, Robinson ML, Farrand AJ, Novosad BD, Callegan MC. Toward improving therapeutic regimens for Bacillus endophthalmitis. Invest Ophthalmol Vis Sci 2008; 49:1480-7. [PMID: 18385066 DOI: 10.1167/iovs.07-1303] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Bacillus cereus causes the most virulent and refractory form of endophthalmitis. The authors analyzed the effectiveness of early treatment with vancomycin or gatifloxacin, with or without dexamethasone, for experimental B. cereus endophthalmitis. METHODS Rabbit eyes were injected intravitreally with 100 colony-forming units of B. cereus. At 2, 4, or 6 hours after infection, eyes were injected intravitreally with 0.1 mL gatifloxacin (0.3%), vancomycin (1.0%), either antibiotic plus dexamethasone, dexamethasone alone (1.0%), or PBS. Eyes were analyzed by electroretinography, bacterial quantitation, and antibiotic penetration analysis. Drug toxicity toward Müller cells, retinal pigment epithelium, and cones was also analyzed. RESULTS Eyes treated at 2 hours with vancomycin or gatifloxacin, with or without dexamethasone, maintained higher ERG amplitudes than the dexamethasone alone and PBS control groups. Eyes treated with antibiotic plus dexamethasone at 6 hours had reduced retinal function compared to antibiotic treatment alone. With the exception of vancomycin with or without dexamethasone at 6 hours, all antibiotic treatments sterilized eyes. Only gatifloxacin reached aqueous concentrations greater than the minimal inhibitory concentration for B. cereus when measured at 8 hours. Neither gatifloxacin nor vancomycin was toxic to retinal cells in vitro. CONCLUSIONS Early intravitreal injection of vancomycin or gatifloxacin improved the therapeutic outcome of B. cereus endophthalmitis. The addition of dexamethasone to antibiotic treatment did not provide a therapeutic benefit over antibiotics alone and appeared to reduce the antibiotic efficacy of vancomycin 6 hours after infection. In this model, delay in treatment past 6 hours significantly reduced the potential for salvaging useful vision.
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Affiliation(s)
- Brandt J Wiskur
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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Moyer AL, Ramadan RT, Thurman J, Burroughs A, Callegan MC. Bacillus cereus induces permeability of an in vitro blood-retina barrier. Infect Immun 2008; 76:1358-67. [PMID: 18268029 PMCID: PMC2292856 DOI: 10.1128/iai.01330-07] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 11/06/2007] [Accepted: 01/28/2008] [Indexed: 11/20/2022] Open
Abstract
Most Bacillus cereus toxin production is controlled by the quorum-sensing-dependent, pleiotropic global regulator plcR, which contributes to the organism's virulence in the eye. The purpose of this study was to analyze the effects of B. cereus infection and plcR-regulated toxins on the barrier function of retinal pigment epithelium (RPE) cells, the primary cells of the blood-retina barrier. Human ARPE-19 cells were apically inoculated with wild-type or quorum-sensing-deficient B. cereus, and cytotoxicity was analyzed. plcR-regulated toxins were not required for B. cereus-induced RPE cytotoxicity, but these toxins did increase the rate of cell death, primarily by necrosis. B. cereus infection of polarized RPE cell monolayers resulted in increased barrier permeability, independent of plcR-regulated toxins. Loss of both occludin and ZO-1 expression occurred by 8 h postinfection, but alterations in tight junctions appeared to precede cytotoxicity. Of the several proinflammatory cytokines analyzed, only interleukin-6 was produced in response to B. cereus infection. These results demonstrate the deleterious effects of B. cereus infection on RPE barrier function and suggest that plcR-regulated toxins may not contribute significantly to RPE barrier permeability during infection.
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Affiliation(s)
- A L Moyer
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center,Oklahoma City, OK 73104, USA
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Bibliography. Current world literature. Neuro-ophthalmology. Curr Opin Ophthalmol 2007; 18:515-17. [PMID: 18163005 DOI: 10.1097/icu.0b013e3282f292cf] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Introduction of a Qualified Presumption of Safety (QPS) approach for assessment of selected microorganisms referred to EFSA - Opinion of the Scientific Committee. EFSA J 2007. [DOI: 10.2903/j.efsa.2007.587] [Citation(s) in RCA: 243] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Callegan MC, Gilmore MS, Gregory M, Ramadan RT, Wiskur BJ, Moyer AL, Hunt JJ, Novosad BD. Bacterial endophthalmitis: therapeutic challenges and host-pathogen interactions. Prog Retin Eye Res 2007; 26:189-203. [PMID: 17236804 PMCID: PMC1941835 DOI: 10.1016/j.preteyeres.2006.12.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Endophthalmitis is an infection of the posterior segment of the eye that frequently results in loss of vision. This devastating result occurs despite prompt and often aggressive therapeutic and surgical intervention. Over the past decade, research has centered on determining the bacterial and host factors involved in this potentially blinding disease. The initial focus on the bacterial factors responsible for intraocular virulence has recently expanded into analysis the inflammatory response to infection, including the molecular and cellular interactions between the pathogen and host. This review discusses the epidemiology and therapeutic challenges posed by endophthalmitis, as well as recent findings from the analysis of interactions between the host and pathogen. Based on these findings, a model for the pathogenesis of endophthalmitis is presented. A more comprehensive understanding of the molecular and cellular interactions taking place between pathogen and host during endophthalmitis will expose possible therapeutic targets designed to arrest the infection and prevent vision loss.
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Affiliation(s)
- Michelle C Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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