Haemophilus influenzae Carriage in Children Attending French Day Care Centers: a Molecular Epidemiological Study

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http://jcm.asm.org/cgi/content/abstract/41/4/1664

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Haemophilus influenzae Carriage in Children Attending French Day Care Centers: a Molecular Epidemiological Study

Henri Dabernat,^1,2* Marie-Anne Plisson-Sauné,² Catherine Delmas,^1,2 Martine Séguy,¹ Gèneviéve Faucon,² Roselyne Pélissier,² Hélène Carsenti,³ Christian Pradier,³ Micheline Roussel-Delvallez,⁴ Joël Leroy,⁵ Marie-Jeanne Dupont,⁵ Frédéric De Bels,⁶ and Pierre Dellamonica³

Laboratoire de Microbiologie, Centre National de Référence des Haemophilus influenzae, Hôpital Purpan,¹ Faculté de Médecine Toulouse Purpan, 31059 Toulouse Cédex 9,² Hôpital de l'Archet, 06202 Nice,³ CHRU, Hôpital Calmette, 59037 Lille Cédex,⁴ CHU Jean Minjoz, 25030 Besançon Cédex,⁵ France INSERM 99-22, CHU Bichat-Claude Bernard, 75877 Paris Cédex 18, France⁶

Received 5 August 2002/ Returned for modification 30 August 2002/ Accepted 9 December 2002

The nasopharyngeal Haemophilus influenzae flora of healthy childrenunder the age of 3 years attending day care centers in threedistinct French geographic areas was analyzed by sampling duringtwo periods, spring 1999 (May and June) and fall 1999 (November and December). The average carrier rate among 1,683 childrenwas 40.9%. The prevalence of capsulated H. influenzae carrierswas 0.4% for type f and 0.6% for type e. No type b strains werefound among these children, of whom 98.5% had received one ormore doses of anti-Haemophilus b vaccine. Among the strains,44.5% were TEM-type beta-lactamase producers and nine (1.3%)were beta-lactamase-negative ampicillin-resistant strains. Pulsed-field gel electrophoresis restriction patterns showed a large diversity with 366 SmaI patterns from 663 strains. Among the strains isolatedduring a given period, 33% were isolated simultaneously in more than one area. In each area, depending on the sampling period,68 to 72% of the strains had new pulsotypes and persistenceof 28 to 32% of the strains was noted. For the 297 beta-lactamase-producingstrains, 194 patterns were found. The genomic diversity of thesestrains was comparable to that of the whole set of strains anddoes not suggest a clonal diffusion. Among the beta-lactamase-producingstrains isolated in November and December, depending on thearea, 66 to 73% had new pulsotypes with persistence of only27 to 33% of the strains. In any given geographic area, colonizationby H. influenzae appears to be a dynamic process involving ahigh degree of genomic heterogeneity among the noncapsulatedcolonizing strains.

* Corresponding author. Mailing address: Laboratoire de Microbiologie, Hôpitaux de Toulouse, CHU Purpan, TSA 40031, 31059 Toulouse Cédex 9, France. Phone: 33 561 77 23 57. Fax: 33 561 77 23 33. E-mail: dabernat.h@chu-toulouse.fr.

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