Research Note— Typing of Haemophilus paragallinarum Strains by Using Enterobacterial Repetitive Intergenic Consensus-Based Polymerase Chain Reaction V. E. Soriano, AC G. Te ´llez, B B. M. Hargis, B L. Newberry, B C. Salgado-Miranda, A and J. C. Va ´zquez A A Centro de Investigacio ´n y Estudios Avanzados en Salud Animal, Facultad de Medicina Veterinaria y Zootecnia, Universidad Auto ´noma del Estado de Me ´xico, Toluca, 50000, Me ´xico B John Kirkpatrick Skeeles Poultry Health Research Laboratory, The Center of Excellence in Poultry Science, Division of Agriculture, University of Arkansas, Fayetteville, AR 72701 Received 19 November 2003; Accepted 14 July 2004 SUMMARY. The enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) technique was used for fingerprinting of reference strains and Mexican isolates of Haemophilus paragallinarum. A total of nine ERIC patterns were given by the nine serovar reference strains of this bacteria. Two Modesto (C-2) reference strains from different sources showed the same ERIC pattern. Seventeen ERIC patterns were obtained among 29 Mexican isolates included in the study, belonging to serovars prevalent in Mexico (A-1, A-2, B-1, and C-2). Obtained results indicate that the ERIC-PCR technique could be used as a molecular laboratory tool for subtyping of H. paragallinarum. RESUMEN. Nota de Investigacio ´n—Tipificacio ´n de cepas de Haemophilus paragallinarum mediante el uso de la reaccio ´n en cadena por la polimerasa en las secuencias repetitivas interge ´nicas de consenso en Enterobacterias. Se utilizo ´ la te ´cnica de reaccio ´n en cadena por la polimerasa en las secuencias repetitivas interge ´nicas de consenso (ERIC-PCR por sus siglas en Ingle ´s) con el fin de tipificar las huellas dactilares gene ´ticas de cepas de referencia y cepas de campo Mexicanas de Haemophilus paragallinarum. Se obtuvo un total de 9 patrones de ERIC a partir de igual nu ´mero de cepas de referencia de la bacteria. Dos cepas de referencia, Modesto (C-2) obtenidas a partir de diferentes fuentes, mostraron el mismo patro ´n de ERIC. Se obtuvieron 17 patrones de ERIC a partir de 29 aislados de la bacteria obtenidos en Me ´xico, los cuales pertenecen a los serovares prevalecentes en el paı ´s (A-1, A-2, B-1, y C-2). Los resultados obtenidos indican que la te ´cnica de ERIC- PCR puede ser utilizada como una herramienta molecular para la tipificacio ´n de cepas de H. paragallinarum. Key words: Haemophilus paragallinarum, ERIC-PCR, fingerprinting, typing Abbreviations: ERIC ¼ enterobacterial repetitive intergenic consensus; PCR ¼ polymerase chain reaction Haemophilus paragallinarum is the causative agent of infectious coryza of chickens (5). The largest economic losses result from poor growth perfor- mance and a marked reduction (10%–40%) in egg production. The disease can have a significant impact in meat chickens (5). Serology has, so far, been the main typing method for H. paragallinarum (2). The Page scheme (13) was initially developed by using either a plate C Corresponding author. CIESA-FMVZ-UAEM, Insti- tuto Literario No. 100, Col. Centro, Toluca, 50000, Estado de Me ´xico, Me ´xico. 890 AVIAN DISEASES 48:890–895, 2004