Pasteurella multocida involved in respiratory disease of wild chimpanzees

Abstract

Pasteurella multocida can cause a variety of diseases in various species of mammals and birds throughout the world but nothing is known about its importance for wild great apes. In this study we isolated P. multocida from wild living, habituated chimpanzees from Taï National Park, Côte d'Ivoire. Isolates originated from two chimpanzees that died during a respiratory disease outbreak in 2004 as well as from one individual that developed chronic air-sacculitis following this outbreak. Four isolates were subjected to a full phenotypic and molecular characterisation. Two different clones were identified using pulsed field gel electrophoresis. Multi Locus Sequence Typing (MLST) enabled the identification of previous unknown alleles and two new sequence types, ST68 and ST69, were assigned. Phylogenetic analysis of the superoxide dismutase (sodA) gene and concatenated sequences from seven MLST-housekeeping genes showed close clustering within known P. multocida isolated from various hosts and geographic locations. Due to the clinical relevance of the strains described here, these results make an important contribution to our knowledge of pathogens involved in lethal disease outbreaks among endangered great apes.

Figure 1. Dendrogram showing macrorestriction patterns of P. multocida isolates after digestion with SmaI.

Cluster analysis of Dice similarity indices (UPGMA) was exerted to generate a dendrogram depicting the relationships among PFGE profiles using the BioNumerics software (optimisation 0.5%, position tolerance 1.0%). P. multocida reference strain ATCC 43137 served as methodological control.

Figure 2. Phylogenetic analysis of the sodA gene.

The tree was built using the maximum-likelihood method from an analysis of sodA sequences (452 bp) from the chimpanzee's isolates and sequences obtained from GenBank. Isolates belonging to the species P. multocida are boxed grey; the chimpanzees isolates are written in bold. Taxon labels indicate species and strain number, including strains with identical sodA sequences (species and subspecies assignments are according to Gautier et al. (2005) [28]). P. langaensis and P. bettyae were used as outgroup. Bootstrap values were calculated with 500 replicates and are given in percent.

Figure 3. Radial Maximum Likelihood trees constructed with concatenated housekeeping gene allele sequences used for MLST analysis.

Shown left is the complete MLST tree constructed with 73 sequence types (STs) and the position of the type strains for the P. multocida subspecies (P. multocida ssp. septica: CIPA125; P. multocida ssp. multocida: NCTC10322; P. multocida ssp. gallicida: NCTC10204). The position of the chimpanzee isolates (boxed grey) is displayed in the subtree (A). STs are labelled with coloured dots indicating the isolation sources and ST numbers. Bold branches indicate for bootstrap values >70%.