Occurrence and Characterization of Salmonella Hiduddify from Chickens and Poultry Meat in Nigeria Ibrahim Raufu, 1 Rene S. Hendriksen, 2 J.A. Ameh, 1 and Frank M. Aarestrup 2 Abstract The objective of this study was to determine the prevalence of Salmonella serovars and the antimicrobial sus- ceptibility in chickens and poultry meat products in rural areas in Nigeria. The study was an observational cross- sectional investigation in which the target population included exotic and local chickens in Maiduguri main markets, chickens from farms, and free-range local chickens. A total of 865 samples were collected from feces, kidney, lungs, cecum, intestine, liver, heart, gizzard, and cloacal swabs from 525 different chickens. Salmonella was isolated from 130 of the samples. A stratified random sampling technique was used to select 41 isolates out of the 130 strains for serotyping, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing. Thirty-nine out of the 41 samples serotyped yielded Salmonella Hiduddify; two yielded a rough Salmonella serovar. The 39 Salmonella Hiduddify isolates and the two rough isolates were highly similar by PFGE typing, indicating that all of the isolates were of the same serovar. A low frequency of resistance was found among the isolates, except for resistance to ciprofloxacin for which 23 (56%) of the isolates tested exhibited resistance. This study documents for the first time the isolation of Salmonella Hiduddify in chickens and shows that this serovar is widespread in rural areas in Nigeria. It also documents a high frequency of fluoroquinone resistance in the isolates indicating the presence of selective pressure in the environment. Further studies should be conducted to reveal if the serovar is present in eggs and causes salmonellosis among the general population. Introduction S almonella enterica is a common cause of human gastroenteritis and bacteremia, and a wide variety of an- imals, particularly food animals, have been identified as res- ervoirs for non-Typhi Salmonella (Coyle, 1988; Humphrey 1988, 2000; Mead, 1999; Adak et al., 2002; Hald et al., 2007). However, poultry are often considered the most common vehicle for human Salmonella infection in humans (Braden, 2006). It has been estimated that over 1.4 million cases of salmonellosis occur each year in the United States alone (Galanis et al., 2006). Although 2587 serovars of S. enterica have been identified, most human infections are caused by a limited number of serovars. In developed countries, S. enterica serovars Typhimurium and Enteritidis are the most common causes of human salmonellosis, although other serovars have been reported to be more prevalent in specific regions (Humphrey, 2000; Herikstad et al., 2002; Bangtrakulnonth et al., 2004). Recently, the isolation of new strains and serovars of Sal- monella in some countries and the increase in the isolation of antimicrobial-resistant strains, especially those resistant to fluoroquinolone and nalidixic acid, have become a cause for concern. This shift in prevalence of specific strain types and serovars can reflect the influence of international travel and trade of animals and food products (Aarestrup et al., 2007). Antimicrobial susceptibility profiles and genetic strain typing methods are useful epidemiological tools to determine the source of infections including potential risk factors be- tween food, animals, and humans. It has previously been shown that pulsed-field gel electrophoresis (PFGE) is highly discriminatory and useful for the validation of typing meth- ods used in bacterial epidemiology (Liebana et al., 2002; Belkum et al., 2007). A study conducted in 2001 to determine the prevalence of S. enterica serovar Enteritidis in Maiduguri, Nigeria found Salmonella in 27% (n ¼ 150) chicken meat samples, of which eight were Salmonella Enteritidis (Ameh et al., 2001). 1 Faculty of Veterinary Medicine, Department of Veterinary Microbiology, University of Maiduguri, Maiduguri, Nigeria. 2 WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and EU Community Reference Laboratory for Anti- microbial Resistance, National Food Institute, Technical University of Denmark, Bu ¨ llowsvej, Copenhagen, Denmark. FOODBORNE PATHOGENS AND DISEASE Volume 6, Number 4, 2009 ª Mary Ann Liebert, Inc. DOI: 10.1089=fpd.2008.0150 425