JID 1992; 165 (March) Concise Communications 569 tive pneumonia study: implications for underdiagnosis. JAMA 1983;249:3184-92. 1 I. Dournon E, Bibb WF. Rajagopalan P, Desplaces N. McKinney RM. Monoclonal antibody reactivity as a virulence marker for Legione/la pneumophila serogroup I strains. J Infect Dis 1988;157:496-501. 12. World Health Organization. Epidemiology. prevention and control of legionellosis: memorandum from a WHO meeting. Bull World Health Organ 1990;68:155-64. 13. Alary M. Joly JR. Risk factors for the contamination of domestic hot water systems by Legionellaceae. Appl Environ Microbiol 1991 ;57:2360-7. 14. Ciesielski CA, Blaser MJ, Wang WL. Role of stagnation and obstruc- tion of water flow in isolation of Legione/la pneumophila from hospi- tal plumbing. Appl Environ Microbiol 1984;48:984-7. 15. Stout JE, Yu VL, Best MG. Ecology of Legione/la pneumophila within water distribution systems. Appl Environ MicrobioI1985;49:221-8. Analysis of DNA Restriction Fragment Length Polymorphism Extends the Evidence for Breast Milk Transmission in Streptococcus agalactiae Late-Onset Neonatal Infection Edouard Bingen, Erick Denamur, Nicole Lambert-Zechovsky, Yannick Aujard, N alma Brahimi, Pierre Geslin, and Jacques Elion Laboratoires de Bacteriologic and Biochimie Genhique. Service de Neonatologie et I NSERM U J20. Hiipital Robert Debre, Paris; Laboratoire de Bacteriologic. Centre Hospitalier Intercommunal de Creteil, France Analysis of restriction fragment length polymorphism (RFLP) of total DNA and of ribosomal DNA (ribotyping) was used to document four cases of Streptococcus agalactiae mother-to-infant transmission potentially associated with ingestion of infected mother's milk. Twenty strains were analyzed. Ten strains were mother-baby pairs, five from the milk of five mothers, four from their neonates with late-onset infection, and one from a colonized neonate. All mothers had early postpartum mastitis. Ten unrelated strains were studied for comparison. In each case, the two strains of each mother-baby pair produced identical RFLP patterns of total DNA. The 10 unre- lated strains generated 10 different patterns, one of which, though, was observed in one of the mother-baby pairs. Ribotyping was less discriminative than total DNA RFLP analysis (6 differ- ent patterns vs. 13). These data extend the evidence for breast milk transmission in S. agalactiae late-onset neonatal infection. Streptococcus agalactiae is the major cause of severe infec- tion during the first 2 months of life [I]. Acquisition of S. agalactiae by neonates in the early-onset type of infection is clearly vertical from the maternal genital tract in utero or during passage through the birth canal [I]. But the mode of transmission of S. agalactiae in infants with late-onset dis- ease is not so well defined. Previous studies have provided evidence that infants acquire the organism from their mothers [1], nosocomially, via the contaminated hands of nursery personnel [2], or, occasionally, from community contacts [3]. It has been also suggested that maternal strepto- cocci may be transmitted by breast-feeding [4-6]. Study of the modes of transmission in these infections has been some- what hampered by the lack of a sufficiently discriminatory typing system. Received 3 July 1991; revised 23 September 1991. Reprints or correspondence: Dr. E. Bingen. Laboratoire de Bacteriologic, Hopital Robert Debre, 48 Bd Serurier, 75019 Paris, France. The Journal of Infectious Diseases 1992;165:569-73 © 1992 by The University of Chicago. All rights reserved. 0022-1899/92/6503-0027$01.00 In this study, we analyzed the restriction fragment length polymorphism (RFLP) of total DNA and of ribosomal DNA (rDNA) regions (ribotyping) to document four cases of S. agalactiae vertical mother-to-infant transmission associated with ingestion of infected mother's milk. Materials and Methods Patient population. Patients were from the obstetric and newborn services and from the neonatal intensive care unit at the Hopital Robert Debre, Paris, a children's hospital. Five mother-baby pairs were studied (table 1). All mothers had post- partum mastitis with erythema, pain, and tenderness in the sub- areolar region but all continued breast-feeding until infant col- onization or infection was ascertained. Two patients subse- quently developed a breast abscess. Of the five neonates, four had a late-onset infection with meningitis (one case), arthritis (one case), and urinary tract infection (two cases). One neonate was colonized with S. agalactiae. The mean age of the four neo- nates at the onset of infection was 11 days (range, 5-19). Bacterial strains. Twenty strains of S. agalactiae were se- lected for study. Ten were mother-baby pairs (table 1). Five were from maternal breast milk of five mothers with a mean at Assistance Publique - Hopitaux De Paris on March 30, 2014 http://jid.oxfordjournals.org/ Downloaded from