title: Staphylococcus epidermidis with the icaA⁻/icaD⁻/IS256⁻ genotype and protein or protein/extracellular-DNA biofilm is frequent in ocular infections.
abstract: In ocular infections (OIs) caused by Staphylococcus epidermidis, biofilms composed mainly of poly-N-acetylglucosamine (PNAG) have been widely studied, but PNAG-independent biofilms have not. Therefore, we searched for a relationship between the ica operon (involved in PNAG-biofilm) and the biochemical composition of biofilms in isolates from OI. Isolates from OI (n = 62), from healthy conjunctiva (HC; n = 45) and from healthy skin (HS; n = 53), were used to detect icaA and icaD genes, and the insertion sequence 256 (IS256) using PCR. The compositions of the biofilms were determined by treatment with NaIO₄, proteinase K and DNase I. Multilocus sequence typing (MLST) was performed to characterize the isolates, and the expression of aap and embp genes was determined by real-time qPCR. A strong relationship between the icaA(-)/icaD(-)/IS256(-) genotype and protein- or protein/extracellular DNA (eDNA)-biofilm composition was found in the isolates from OI (53.6%), whereas the icaA(+)/icaD(+)/IS256(-) genotype and carbohydrate-biofilm was most prevalent in isolates from HC (25%) and HS (25%). Isolates with an icaA(-)/icaD(-)/IS256(-) genotype and protein-biofilm phenotype were predominantly of the ST2 lineage, while carbohydrate-biofilm-producing strains were mainly of the ST9 lineage. The protein-biofilm-producing strains had higher expression levels of aap gene than carbohydrate-biofilm-producing strains; while embp gene did not have the same pattern of expression. These results suggest that S. epidermidis strains with icaA(-)/icaD(-)/IS256(-) genotype and protein- or protein/eDNA-biofilms have a stronger ability to establish in the eye than S. epidermidis strains with icaA(+)/icaD(+)/IS256(-) genotype and PNAG-biofilms.
authors.affiliation: Department of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. CP 11340 Mexico City, Mexico.
authors.forename: Marco A
authors.initials: MA
authors.lastname: Juárez-Verdayes
authors.affiliation: Department of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. CP 11340 Mexico City, Mexico.
authors.forename: Miriam L
authors.initials: ML
authors.lastname: Ramón-Peréz
authors.affiliation: Department of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. CP 11340 Mexico City, Mexico.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Flores-Páez
authors.affiliation: Department of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. CP 11340 Mexico City, Mexico.
authors.forename: Omar
authors.initials: O
authors.lastname: Camarillo-Márquez
authors.affiliation: Instituto de Oftalmología Fundación Conde de Valenciana, Chimalpopoca No. 14, Col. Obrera, Deleg. Cuauhtémoc. CP 06800 Mexico City, Mexico.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Zenteno
authors.affiliation: Department of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. CP 11340 Mexico City, Mexico.
authors.forename: Janet
authors.initials: J
authors.lastname: Jan-Roblero
authors.affiliation: Immunology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. CP 11340 Mexico City, Mexico.
authors.forename: Mario E
authors.initials: ME
authors.lastname: Cancino-Diaz
authors.affiliation: Department of Microbiology, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Santo Tomas. Deleg. Miguel Hidalgo. CP 11340 Mexico City, Mexico.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Cancino-Diaz
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D015817:Eye Infections / Q000453:epidemiology* / Q000382:microbiology; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D058885:Multilocus Sequence Typing; D016133:Polymerase Chain Reaction; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013212:Staphylococcus epidermidis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D037521:Virulence Factors / Q000172:deficiency*
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; D037521:Virulence Factors