REVIEW ARTICLE published: 27 September 2011 doi: 10.3389/fmicb.2011.00200 Campylobacter spp. as a foodborne pathogen: a review Joana Silva, Daniela Leite, Mariana Fernandes, Cristina Mena, Paul Anthony Gibbs and PaulaTeixeira* CBQF/Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal Edited by: Kostas Koutsoumanis, Aristotle University, Greece Reviewed by: SandraTorriani, Università degli Studi di Verona, Italy Alexandra Lianou, Aristotle University of Thessaloniki, Greece *Correspondence: PaulaTeixeira, CBQF/Escola Superior de Biotecnologia, Universidade Católica Portuguesa, R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal e-mail: pcteixeira@esb.ucp.pt Campylobacter is well recognized as the leading cause of bacterial foodborne diarrheal disease worldwide. Symptoms can range from mild to serious infections of the children and the elderly and permanent neurological symptoms. The organism is a cytochrome oxidase positive, microaerophilic, curved Gram-negative rod exhibiting corkscrew motil- ity and is carried in the intestine of many wild and domestic animals, particularly avian species including poultry. Intestinal colonization results in healthy animals as carriers. In contrast with the most recent published reviews that cover specific aspects of Campy- lobacter /campylobacteriosis, this broad review aims at elucidating and discussing the (i) genus Campylobacter, growth and survival characteristics; (ii) detection, isolation and con- firmation of Campylobacter ; (iii) campylobacteriosis and presence of virulence factors; and (iv) colonization of poultry and control strategies. Keywords: Campylobacter spp., foodborne pathogens, virulence factors, antimicrobial susceptibility, control measures THE GENUS CAMPYLOBACTER It is believed that the first report concerning Campylobacter was back in 1886 by Theodore Escherich who observed and described non-culturable spiral-shaped bacteria ( Vandamme, 2000; King and Adams, 2008; Vandamme et al., 2010). After this, Campy- lobacter was identified for the first time in 1906 when two British veterinarians reported the presence of “large numbers of a pecu- liar organism” in the uterine mucus of a pregnant sheep (Skirrow, 2006; Zilbauer et al., 2008). In 1913, McFadyean and Stockman isolated these microorganisms from aborted bovine fetuses. Later in 1927, Smith and Orcutt named a group of bacteria, isolated from the feces of cattle with diarrhea, as Vibrio jejuni. Seven- teen years later, in 1944, Doyle isolated a different vibrio from feces of pigs with diarrhea and classified them as Vibrio coli (Van- damme, 2000; Vandamme et al., 2010). Due to their low DNA base composition, their non-fermentative metabolism and their microaerophilic growth requirements, the genus Campylobacter was first proposed in 1963 by Sebald and Véron, distinguishing them from the “true” Vibrio spp. (On, 2001). After that, the study of Butzler et al. (1973) raised the interest in Campylobacter by noting their high incidence in human diarrhea (On, 2001). Since its inception, the taxonomic structure of the genus Campylobacter has experienced extensive changes and even some parts of the cur- rent genus taxonomy remain a matter of controversy and require further investigation (On, 2001; Debruyne et al., 2005). According to these latter authors, Debruyne et al. (2005), there are 14 validly described Campylobacter species. More recently, Fernández et al. (2008) stated that the genus comprises 20 species and subspecies. However, other authors have stated that there are 16 species with a further six subspecies within the genus Campylobacter (On, 2001; Foster et al., 2004). Campylobacters have been known to be the cause of diseases in animals since 1909, but they have been generally recognized as a cause of human disease, only since about 1980. The family Campylobacteraceae consists of two genera, Campy- lobacter and Arcobacter and occur primarily as commensals in humans and domestic animals (Vandamme, 2000). The genus Campylobacter contains small (0.2–0.8 μm × 0.5–5 μm) Gram- negative, slender spirally curved rods. When two or more bacterial cells are grouped together, they form an “S” or a “V” shape of gull- wing. The majority of the species have a corkscrew-like motion by means of a single polar unsheathed flagellum at one or both ends of the cell. The only exceptions are Campylobacter gracilis which is non-motile and Campylobacter showae which has multiple flagella (see Debruyne et al., 2005 for a comprehensive description of the taxonomy of Campylobacteraceae). Oxidase activity is present in all species except for C. gracilis. They neither ferment nor oxidize carbohydrates; instead they obtain energy from amino acids, or tricarboxylic acid cycle intermediates (Vandamme, 2000). Campy- lobacter jejuni hydrolyzes hippurate, indoxyl acetate and reduces nitrate. Most strains are resistant to cephalothin, and also resis- tance to fluoroquinolones, a category of antibiotics normally used to treat animal and human illness, has been reported (Koenraad et al., 1995). Under unfavorable growth conditions, these microorganisms have the ability to form viable but non-culturable cells (VBNC; Portner et al., 2007). Cappelier (1997), observed under labora- tory conditions, that Campylobacter strains, isolated from the soil around the broiler house, may have been transformed into viable but non-cultivable forms and might have become cultivable after passing through the intestinal tract of chickens. Many ques- tions have been raised on whether non-culturability equates to non-viability (McKay, 1992), whether it is possible to convert the VBNC form to a culturable form (Jones et al., 1991; Beumer et al., 1992; Stern et al., 1994), and whether, indeed, a VBNC form of Campylobacter actually exists (ACMSF, 2004). GROWTH AND SURVIVAL CHARACTERISTICS Thermophilic Campylobacter species are able to grow between 37 and 42˚C, but incapable of growth below 30˚C (absence of cold shock protein genes which play a role in low-temperature adaptation), with an optimum temperature of 41.5˚C. Levin www.frontiersin.org September 2011 |Volume 2 | Article 200 | 1