title: Clinical relevance and virulence factors of pigmented Serratia marcescens.
abstract: Pigmented Serratia marcescens isolated in a Brazilian hospital were studied with respect to frequency of isolation, serotyping, antibiotic resistance and virulence factors. The serotype most frequent was O6:K14 (53%) and all isolates were resistant to ampicillin, cephalothin and tetracycline. The majority of the isolates (92%) were resistant to the action of human serum and all produced cytotoxins on Vero, CHO, HEp-2 and HeLa cells. These isolates were virulent for mice (LD(50)=10(7) bacteria ml(-1)) and showed virulence factors, but were isolated with low frequency (3. 4%) and caused infection in only 31% of cases. Analysis of serotyping, phage typing and chromosomal DNA revealed at least 13 unrelated strains among pigmented S. marcescens. In conclusion, this work describes a low frequency of isolation of pigmented S. marcescens from clinical specimens, indicating that non-pigmented strains are clinically more significant.
authors.affiliation: Departamento de Microbiologia e Imunologia, Universidade Estadual de Campinas, Sao Paulo, Brazil.
authors.forename: G V
authors.initials: GV
authors.lastname: Carbonell
authors.forename: H H
authors.initials: HH
authors.lastname: Della Colleta
authors.forename: T
authors.initials: T
authors.lastname: Yano
authors.forename: A L
authors.initials: AL
authors.lastname: Darini
authors.forename: C E
authors.initials: CE
authors.lastname: Levy
authors.forename: B A
authors.initials: BA
authors.lastname: Fonseca
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001938:Brazil / Q000453:epidemiology; D016466:CHO Cells; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003428:Cross Infection / Q000382:microbiology; D003603:Cytotoxins / Q000378:metabolism; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D010957:Plasmids; D012141:Respiratory Tract Infections / Q000382:microbiology; D012703:Serotyping; D016868:Serratia Infections / Q000453:epidemiology / Q000382:microbiology*; D012706:Serratia marcescens / Q000235:genetics / Q000472:pathogenicity*; D014709:Vero Cells; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D003603:Cytotoxins