Emergence, Distribution, and Molecular and Phenotypic Characteristics ofSalmonella entericaSerotype 4,5,12:i:–

Abstract

Salmonella spp. represent one of the most common causes of bacterial foodborne illnesses around the world. The species Salmonella enterica contains more than 2500 serotypes, and emergence of new human pathogenic Salmonella strains and serotypes represents a major public health issue. Salmonella enterica subsp. enterica serotype 4,5,12:i:- represents a monophasic variant of Salmonella Typhimurium, which has rarely been identified before the mid-1990 s. The prevalence of this serotype among human salmonellosis cases has increased considerably since the mid-1990 s and Salmonella 4,5,12:i:- currently (i.e., the first decade of the 2000s) represents one of the most common serotypes among human cases in many countries around the world. This paper discusses our current knowledge of the global ecology, epidemiology, transmission, and evolution of this emerging Salmonella serotype.

Molecular Characterization of Salmonella enterica Serovar Typhimurium Isolated from Human, Food, and Animal Sources in Malaysia

“…In this study, we found only 1 monophasic variant of S. Typhimurium (STM032/04) from a hospitalized patient in 2004. It has been known that the majority of Salmonella 4, [5],12:i:-strains reported in European and Asian countries showed MDR phenotypes (8). We found that the monophasic STM032/04 strain in this study was resistant to AMP, GEN, and TET, in addition to NAL; this finding was similar to those obtained for monophasic strains in Thailand (37).…”

“…The worldwide emergence and spreading of monophasic Salmonella 4, [5],12:i:-has been reported since 1990s (8). In Asia, the isolation of this clinically important NTS from clinical samples has been reported in Thailand and Taiwan (35,36) but not in Malaysia.…”

“…Typhimurium (antigenic profile 4, [5],12:i:1,2) shows motility by means of peritrichous flagella. These flagella are made up of either of the 2 types of flagellar antigens (H:i and H:1,2), which are encoded by flagellin genes fliC and fljB, respectively (8). Phase transition of biphasic S. Typhimurium is achieved by switching between the expressions of the above-mentioned flagellin genes (9).…”

“…Phase transition of biphasic S. Typhimurium is achieved by switching between the expressions of the above-mentioned flagellin genes (9). However, since the mid-1990s, a worldwide increase has been observed in the prevalence of Salmonella 4, [5],12:i:-, a monophasic variant of S. Typhimurium (8,10). Similar to their biphasic counterparts, many of the monophasic variants also show multidrug resistance (10), and therefore, pose an additional threat to public health.…”

Salmonella enterica Typhimurium fljBA operon stability: implications regarding the origin of Salmonella enterica I 4,[5],12:i:-

“…Salmonella enterica subspecies (subsp) enterica serovar 4, [5],12:i:-has been frequently isolated from humans and other animals worldwide (reviewed by Moreno-Switt et al, 2009). Considered an emergent and multi-drug resistant serovar, S. enterica 4,5,12:i:-has been responsible for outbreaks in several continents (Echeita and Usera, 1998;Amavist et al, 2005;Mossong et al, 2006;Hauser et al, 2010;Hopkins et al, 2010;CDC, 2011;Raguenaud et al, 2012;Guillier et al, 2013;Mandilara et al, 2013;Gallati et al, 2013;Mulvey et al, 2013;Arguello et al, 2014;Garcia et al, 2014).…”