An examination of the clonal variants of Serratia marcescens that infect the eye during contact lens wear

Hume, Emma B.H.; Willcox, Mark; Sweeney, Deborah F.; Ba, Holden

doi:10.1099/00222615-45-2-127

Cited by 14 publications

(6 citation statements)

References 23 publications

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“…Moreover, this organism is a good colonizer of living and inanimate surfaces. For example, S. marcescens strains can consistently be isolated from contact lenses and contact lens cases (19,31), and S. marcescens MG1 has previously been shown to colonize tomato roots (60). In light of this general control, we studied QS regulation of attachment and found that QS mediates attachment to some surfaces, such as hydrophilic, polystyrene microtiter plates.…”

Section: Discussionmentioning

confidence: 99%

Quorum-Sensing Regulation of Adhesion in Serratia marcescens MG1 Is Surface Dependent

et al. 2007

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Serratia marcescens is an opportunistic pathogen and a major cause of ocular infections. In previous studies of S. marcescens MG1, we showed that biofilm maturation and sloughing were regulated by N-acyl homoserine lactone (AHL)-based quorum sensing (QS). Because of the importance of adhesion in initiating biofilm formation and infection, the primary goal of this study was to determine whether QS is important in adhesion to both abiotic and biotic surfaces, as assessed by determining the degree of attachment to hydrophilic tissue culture plates and human corneal epithelial (HCE) cells. Our results demonstrate that while adhesion to the abiotic surface was AHL regulated, adhesion to the HCE cell biotic surface was not. Type I fimbriae were identified as the critical adhesin for non-QS-mediated attachment to the biotic HCE cell surface but played no role in adhesion to the abiotic surface. While we were not able to identify a single QS-regulated adhesin essential for attachment to the abiotic surface, four AHL-regulated genes involved in adhesion to the abiotic surface were identified. Interestingly, two of these genes, bsmA and bsmB, were also shown to be involved in adhesion to the biotic surface in a non-QS-controlled fashion. Therefore, the expression of these two genes appears to be cocontrolled by regulators other than the QS system for mediation of attachment to HCE cells. We also found that QS in S. marcescens regulates other potential cell surface adhesins, including exopolysaccharide and the outer membrane protein OmpX. We concluded that S. marcescens MG1 utilizes different regulatory systems and adhesins in attachment to biotic and abiotic surfaces and that QS is a main regulatory pathway in adhesion to an abiotic surface but not in adhesion to a biotic surface.

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Section: Discussionmentioning

confidence: 99%

Quorum-Sensing Regulation of Adhesion in Serratia marcescens MG1 Is Surface Dependent

et al. 2007

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“…Serratia marcescens has been implicated in both CLARE and corneal ulceration, but may also colonize the eye in low numbers without any overt pathogenic symptoms (5). This study has shown that there are differences between isolates of S. marcescens in their ability to evade complement attack, which may have implications for the pathogenicity of these ocular isolates.…”

Section: Discussionmentioning

confidence: 73%

“…The type of O-antigen may also confer complement resistance (27). These strains have previously been shown to have different O-antigens (5), so this may be an additional mechanism determining complement resistance. The complement-resistant strains produced far more endotoxin than the complement-sensitive isolates and this was correlated.…”

Section: Discussionmentioning

confidence: 99%

“…Six strains of S. marcescens were used (Table I). The assigned 'types' have been allocated according to a combination of biotype, serotype and ribotype pro les as published previously (5). Capsulation type was determined by Dr. Hazel Aucken from the Public Health Laboratory Service, Central Public Health Laboratory, Colindale, London, UK.…”

Section: Bacteriamentioning

confidence: 99%

“…CLARE is one of the major reasons contact lens wearers discontinue using contact lens and occurs speci cally during the overnight wear of contact lenses, resulting in pain, photophobia, tearing and reddening of the conjunctiva. However, strains have also been isolated from eyes wearing contact lens with no apparent in ammation occurring (5). Greater numbers of bacteria are usually isolated during active contact lens-related infection or in ammation than during non-in ammatory episodes (4).…”

Section: Introductionmentioning

confidence: 99%

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Survival ofSerratia marcescensin the Presence of Complement

Hume

Willcox

2001

Microbial Ecology in Health and Disease

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Serratia marcescens has been isolated from a variety of ocular infections and:or in ammation. In order to survive in the eye, strains must be able to resist host defence systems. Complement has been shown to have an increased concentration and to be active during sleep. Not only is the complement system involved in host defence, but its activation can also produce in ammation. The aim of the present study was to examine the ability of ocular isolates of S. marcescens to withstand complement attack, activate complement and to examine the mechanisms used for evasion of this host defence system. The majority of isolates tested (4:6) were resistant to complement attack. These isolates were able to activate both complement pathways, as detected by enzyme-linked immunosorbent assays (ELISA) and western blotting assays. Components detected included C4, Factor B, C3 and C5. Possible mechanisms of resistance were elucidated including quantity of lipopolysaccharide (LPS) on the cell surface, ability to bind lactoferrin, types of complement components deposited onto the surfaces of strains, and the amount and location of C3 bound on the surface, as determined by transmission electron microscopy. Complement-resistant strains generated iC3b, bound more lactoferrin (1.7 9 0.6 for resistant cells compared with 0.4 90.2 for complement-sensitive cells, relative values), and had larger amounts of extractable endotoxin (216.8 988.8 m g:ml for resistant strains and 36.0 948.4 mg:ml for sensitive strains). Although there was no direct correlation between the ability to resist and activate complement and the isolation of strains from symptomatic or asymptomatic eyes, the resistance of strains to complement may allow these strains to remain in the eye and the activation of complement may contribute to the in ammatory response seen during infection or ocular in ammation.

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Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis

Singh

Das

Chodosh

et al. 2022

Progress in Retinal and Eye Research

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An examination of the clonal variants of Serratia marcescens that infect the eye during contact lens wear

Cited by 14 publications

References 23 publications

Quorum-Sensing Regulation of Adhesion in Serratia marcescens MG1 Is Surface Dependent

Quorum-Sensing Regulation of Adhesion in Serratia marcescens MG1 Is Surface Dependent

Survival ofSerratia marcescensin the Presence of Complement

Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis

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