Recovery of Bordetella bronchiseptica sequence type 82 and B. pseudohinzii from urban rats in Terengganu, Malaysia

Abstract

Rodents have historically been associated with zoonotic pandemics that claimed the lives of large human populations. Appropriate pathogen surveillance initiatives could contribute to early detection of zoonotic infections to prevent future outbreaks. Bordetella species are bacteria known to cause mild to severe respiratory disease in mammals and, some have been described to infect, colonize and spread in rodents. There is a lack of information on the population diversity of bordetellae among Malaysian wild rodents. Here, bordetellae recovered from lung tissues of wild rats were genotypically characterized using 16S rDNA sequencing, MLST and nrdA typing. A novel B. bronchiseptica ST82, closely related to other human-derived isolates, was discovered in three wild rats (n=3) from Terengganu (5.3333° N, 103.1500° E). B. pseudohinzii, a recently identified laboratory mice inhabitant, was also recovered from one rat (n=1). Both bordetellae displayed identical antimicrobial resistance profiles, indicating the close phylogenetic association between them. Genotyping using the 765-bp nrdA locus was shown to be compatible with the MLST-based phylogeny, with the added advantage of being able to genotype non-classical bordetellae. The recovery of B. pseudohinzii from wild rat implied that this bordetellae has a wider host range than previously thought. The findings from this study suggest that bordetellae surveillance among wild rats in Malaysia has to be continued and expanded to other states to ensure early identification of species capable of causing public health disorder.

Keywords: MLST; bordetellae; infectious disease; nrdA; tropical.

Fig. 1.

Map of Peninsular Malaysia showing the states that were involved in the study; Johor, Kedah, Kelantan and Terengganu, together with the number of bordetellae recovered, indicated below the names of each respective state. The table shows the number of rodents and shrews captured in the individual states.

Fig. 2.

Nucleic acid amplification products of cas9, cas1 and cas2 of B. pseudohinzii TRE152202. Lane 1, B. pseudohinzii BH370 (positive control); Lane 2, B. pseudohinzii TRE152202; Lane 3, B. bronchiseptica TRE151600; Lane 4, B. bronchiseptica TRE150202; Lane 5, B. bronchiseptica TRE155202.

Fig. 3.

Minimum spanning tree of B. bronchiseptica complex I, constructed using PHYLOViZ. Each circle represents individual STs and different colors indicate the host at which B. bronchiseptica was recovered. ST and hosts data were recovered from the Bordetella MLST database at http://pubmlst.org/bordetella/. The novel ST82 was indicated by a circle with dashed lines.

Fig. 4.

Neighbor-joining tree based on nrdA loci of classical and non-classical bordetellae. nrdA locus numbers are indicated behind the bordetellae species names. The nrdA locus numbers were extracted from the Bordetella MLST database at http://pubmlst.org/bordetella/. Bordetellae isolates which have not been classified to the species level were excluded from the study. Separation of complexes I-IV in the classical bordetellae group based on MLST data was consistent with the nrdA sequence analyses. All non-classical bordetellae were clustered separately.