OCCURRENCE OF PASTEURELLACEAE BACTERIA IN THE ORAL CAVITY OF THE TASMANIAN DEVIL ( SARCOPHILUS HARRISII )

Comparative Genome Analysis of Canine Frederiksenia canicola Isolates

Background/Objectives: The One Health approach is crucial for managing and controlling the spread of antimicrobial resistance. Frederiksenia canicola is a recently identified bacterial species that seems to be a component of the oral microbiota of dogs; however, its pathogenic nature is questionable. Methods: In this study, the antibacterial susceptibility of F. canicola isolates was determined using the disk diffusion and broth microdilution methods. Genome-wide comparative analyses were performed to identify the genetic factors driving virulence and antimicrobial drug resistance (e.g., virulence factors, antimicrobial resistance genes (ARGs) and prophage-related sequences). Results: Most of the F. canicola isolates lacked virulence-associated genes. F. canicola is likely resistant to clindamycin, lincomycin and neomycin, but susceptible to penicillin, erythromycin and enrofloxacin. Antimicrobial resistance genes were not found in the F. canicola genomes, but prophage-related sequences were identified, suggesting its potential in the transfer of genes associated with drug resistance between bacteria in the oral microbiome. Conclusions: F. canicola is presumably a commensal organism with low virulence potential, as evidenced by the absence of virulence-associated genes. As F. canicola can colonize a wide range of hosts, including humans, further investigation with a greater number of isolates is needed to better understand the role of F. canicola in disease development and the spread of drug resistance.

MOLECULAR IDENTIFICATION OF MEMBERS OF THE FAMILY PASTEURELLACEAE FROM THE ORAL CAVITY OF KOALAS (PHASCOLARCTOS CINEREUS) AND THEIR RELATIONSHIP WITH ISOLATES FROM KOALA BITE WOUNDS IN HUMANS

A total of 22 Pasteurellaceae isolates obtained from the oral cavity of koalas (Phascolarctos cinereus) at different wildlife centers in Australia were investigated using amplification and sequencing of two housekeeping genes, rpoA and recN. The available sequences from the Lonepinella koalarum type strain (ACM3666^T) and the recent isolates of Lonepinella-like bacteria obtained from human infected wounds associated with koala bites were also included. Phylogenetic analysis was performed on the concatenated rpoA-recN genes and genome relatedness was calculated based on the recN sequences. The oral cavity isolates, the koala bite wound isolates, and L. koalarum ACM3666T resulted in four clusters (Clusters 1-4). Clusters 1-3 were clearly not members of the genus Lonepinella. Cluster 1 was closely related to the genus Fredericksenia, and Clusters 2 and 3 appeared to be novel genera. Cluster 4 consisted of three subclusters: Cluster 4a with one koala bite wound isolate and L. koalarum ACM3666^T, Cluster 4b with three oral cavity isolates and two Lonepinella-like wound isolates, and Cluster 4c with three nearly identical oral cavity isolates that may represent a different species within the genus Lonepinella. The rich Pasteurellaceae population, including potential novel taxa in the oral cavity of koalas supports an important role of these highly adapted microorganisms in the physiology of koalas. Moreover, the pathogenic potential of Lonepinella-like species is an important consideration when investigating infected koala bites in humans.

Occurrence of Pasteurellaceae and Neisseriaceae bacteria in the pharyngeal and respiratory tract of dogs and cats - Short communication

The occurrence of members of the Pasteurellaceae and Neisseriaceae families was studied in dogs and cats. A total of 110 nasal and pharyngeal swab samples from 47 dogs and 8 cats were collected. Most of the strains were identified by 16S rDNA sequencing, except Frederiksenia canicola and Pasteurella multocida where species-specific polymerase chain reactions were applied. The most frequently isolated species was F. canicola, which occurred only in dogs, mainly in the pharyngeal cavity. The second commonest bacterium, P. multocida was found in both types of samples and in both hosts. Other species from the family Pasteurellaceae, such as Haemophilus haemoglobinophilus, Pasteurella canis and P. dagmatis, were detected only in dogs. All isolated species belonging to the family Neisseriaceae, mainly representing Neisseria weaveri, were found only in the pharyngeal cavity. Neisseria weaveri and N. zoodegmatis could be detected in both hosts. Neisseria dumasiana and N. canis were isolated from dogs, while N. shayeganii only from a cat. For phylogenetic analysis, rpoB gene sequencing was performed, where the strains were on monophyletic branches and clearly separated from each other. In this study, recently described species such as F. canicola, N. shayeganii and N. dumasiana were detected that had never been isolated in Hungary before.

Phase variation in latB associated with a fatal Pasteurella multocida outbreak in captive squirrel gliders

A septicaemic disease outbreak caused by Pasteurella multocida at a zoo in Western Australia (Zoo A) occurred in a resident group of squirrel gliders (Petaurus norfolcensis) following the introduction of two squirrel gliders imported from another zoo (Zoo B). P. multocida isolates obtained from the affected animals and asymptomatic, cohabiting marsupials at both zoos were typed via lipopolysaccharide outer core biosynthesis locus (LPS) typing, repetitive extragenic palindromic PCR (Rep-PCR) typing, and multilocus sequence typing (ST). Investigation of isolate relatedness via whole genome sequencing (WGS) and phylogenomic analysis found that the outbreak isolates shared the same genetic profile as those obtained from the imported gliders and the positive marsupials at Zoo B. Phylogenomic analysis demonstrated that these isolates belonged to the same clone (named complex one), confirming that the outbreak strain originated at Zoo B. As well, the carriage of multiple different strains of this pathogen in a range of marsupials in a zoo setting has been demonstrated. Importantly, the genomic investigation identified a missense mutation in the latB, a structural LPS gene, resulting in introduction of an immediate stop codon in the isolates carried by asymptomatic squirrel gliders in Zoo B. The identified diversity in the latB gene of LPS outer core biosynthesis loci of these isolates is consistent with a novel phase variable mechanism for virulence in P. multocida. Our study demonstrates the benefit of WGS and bioinformatics analysis in epidemiological investigations of pasteurellosis and its potential to reveal unexpected insights into bacterial virulence.

Ecology and Host Identity Outweigh Evolutionary History in Shaping the Bat Microbiome

This study is the first to provide a comprehensive survey of bacterial symbionts from multiple anatomical sites across a broad taxonomic range of Afrotropical bats, demonstrating significant associations between the bat microbiome and anatomical site, geographic locality, and host identity—but not evolutionary history. This study provides a framework for future systems biology approaches to examine host-symbiont relationships across broad taxonomic scales, emphasizing the need to elucidate the interplay between host ecology and evolutionary history in shaping the microbiome of different anatomical sites.

Recent studies of mammalian microbiomes have identified strong phylogenetic effects on bacterial community composition. Bats (Mammalia: Chiroptera) are among the most speciose mammals on the planet and the only mammal capable of true flight. We examined 1,236 16S rRNA amplicon libraries of the gut, oral, and skin microbiota from 497 Afrotropical bats (representing 9 families, 20 genera, and 31 species) to assess the extent to which host ecology and phylogeny predict microbial community similarity in bats. In contrast to recent studies of host-microbe associations in other mammals, we found no correlation between chiropteran phylogeny and bacterial community dissimilarity across the three anatomical sites sampled. For all anatomical sites, we found host species identity and geographic locality to be strong predictors of microbial community composition and observed a positive correlation between elevation and bacterial richness. Last, we identified significantly different bacterial associations within the gut microbiota of insectivorous and frugivorous bats. We conclude that the gut, oral, and skin microbiota of bats are shaped predominantly by ecological factors and do not exhibit the same degree of phylosymbiosis observed in other mammals.

IMPORTANCE This study is the first to provide a comprehensive survey of bacterial symbionts from multiple anatomical sites across a broad taxonomic range of Afrotropical bats, demonstrating significant associations between the bat microbiome and anatomical site, geographic locality, and host identity—but not evolutionary history. This study provides a framework for future systems biology approaches to examine host-symbiont relationships across broad taxonomic scales, emphasizing the need to elucidate the interplay between host ecology and evolutionary history in shaping the microbiome of different anatomical sites.

Pasteurellaceae bacteria from the oral cavity of Tasmanian devils (Sarcophilus Harrisii) show high minimum inhibitory concentration values towards aminoglycosides and clindamycin

Threatened by Devil Facial Tumor Disease, the Tasmanian devil populations are vulnerable and decreasing. Additionally, the devils' biting behaviour elevates their risk of acquiring bite wound infections caused by members of the bacterial Pasteurellaceae family that are natural inhabitants of the oral microbiota. In medical management of such bite wounds, antimicrobial susceptibility profiles are crucial. Prior to this investigation, no available data on minimal inhibitory concentration (MIC) values existed. A total of 26 isolates obtained from the oral cavity of 26 healthy Tasmanian devils were tested for their antimicrobial susceptibility by broth micro dilution. Most prominently, high MIC values for clindamycin (≥4 μg ml(-1) ), gentamicin (≥8 μg ml(-1) ) and amikacin (≥32 μg ml(-1) ), were observed for 92, 77 and 73% of the strains tested respectively. This study may be used as a guideline for antimicrobial therapy against bite wound infections caused by Pasteurellaceae originating from the oral cavity of Tasmanian devils.

SIGNIFICANCE AND IMPACT OF THE STUDY

Tasmanian devils' aggressive behaviour makes bite wounds in fellow devils and human caretakers a common entity. Pasteurellaceae bacteria are common inhabitants of the oral microbiota of Tasmanian devils and a likely cause of bite wound infections. Here, for the first time, we report antimicrobial sensitivity profiles from a broad collection of Pasteurellaceae isolates obtained from the oral cavity of Tasmanian devils. Low MIC values were observed for the majority of the 22 antimicrobial agents included, yet nearly all strains were tolerant to clindamycin and the aminoglycosides. The work can serve as a guide for clinicians involved in treatment of bite wounds inflicted by devils in animals and humans.