Molecular characterization of temporally and geographically matched Streptococcus agalactiae strains isolated from food products and bloodstream infections.
In a defined geographic area, during a 3-month period, 914 food products were screened for Streptococcus agalactiae, and S. agalactiae strains isolated from bloodstream infections (BSI) in nonpregnant adults were collected. Eleven S. agalactiae strains were isolated from 1.2% of food products, with high rates in pastries (7.0%) and seafood products (11.8%). These findings indicate that S. agalactiae is a food product contaminant. Seven S. agalactiae BSI were observed in nonpregnant adults representing an incidence of 0.015/100 admissions. The distribution of strains in serotypes did not differ according to origin of the strains; food products and clinical strains were of serotypes Ia (22%), Ib (11%), II (5%), III (22%), IV (5%), and V (33%). The strains isolated from seafoods were of serotypes Ia and Ib. The distribution of strains in Sequence Types differed according to their origin; food strains were equally distributed between the major clonal complex (CC), CC1 (27%), CC9 (18%), CC17 (18%), and CC23 (27%), whereas a high proportion of BSI strains belonged to CC1 (57%). DNA macrorestriction using SmaI revealed diversity; nine different patterns were found for the 11 food strains and seven for the 7 BSI strains. One pattern was similar for two food strains and one BSI strain. On account of the molecular characteristics previously described for S. agalactiae strains of human carriage and fish and mice infections, the serotype characteristics of seafood strains suggest contamination by aquatic S. agalactiae, whereas the molecular characteristics of strains from pastries suggest human contamination, but may also originate from rodents. Indeed, serotype V CC1 strains, found in food and responsible for a high percentage of BSI in nonpregnant adults, belong to a known clone spreading worldwide, and have also been described in mice.
van der Mee-Marquet
Nathalie
N
UFR de Médecine, Bactéries et Risque Materno-Foetal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, Université François-Rabelais de Tours, Tours Cedex, France. n.vandermee@chu-tours.fr
Domelier
Anne-Sophie
AS
Salloum
Mazen
M
Violette
Jérémie
J
Arnault
Laurence
L
Gaillard
Nicolas
N
Bind
Jean-Louis
JL
Lartigue
Marie-Frédérique
MF
Quentin
Roland
R
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology*; D015373:Bacterial Typing Techniques; D003296:Cooking / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D005260:Female; D005502:Food / Q000706:statistics & numerical data; D019649:Food Industry / Q000706:statistics & numerical data; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000145:classification / Q000382:microbiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D011159:Population Surveillance; D017747:Seafood / Q000382:microbiology; D013045:Species Specificity; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification