Human Infections by Wohlfahrtiimonas chitiniclastica: A Mini-Review and the First Report of a Burn Wound Infection after Accidental Myiasis in Central Europe

Wohlfahrtiimonas chitiniclastica are bacteria that cause rare infections, typically associated with the infestation of an open wound with fly larvae. Here, we present a unique case report of the first W. chitiniclastica isolation from a burn wound with accidental myiasis in a 63-year-old homeless man and a literature review focused on human infections caused by these bacteria. So far, 23 cases of infection with W. chitiniclastica have been reported; in 52% of these, larvae were found in the wound area. Most of these cases suffered from chronic non-healing wound infections but none of these were burn injuries. The overall fatality rate associated directly with W. chitiniclastica in these cases was 17%. Infections with parasitic larvae occur in moderate climates (especially in people living in poor conditions); therefore, an infection with rare bacteria associated with accidental myiasis, such as W. chitiniclastica, can be expected to become more common there. Thus, in view of the absence of recommendations regarding the treatment of patients with accidental myiasis and, therefore, the risk of infection with W. chitiniclastica or other rare pathogens, we provide a list of recommendations for the treatment of such patients. The importance of meticulous microbial surveillance using molecular biological methods to facilitate the detection of rare pathogens is emphasized.

First Isolation of Exiguobacterium aurantiacum in Serbia

Exiguobacterium aurantiacum is isolated from a variety of environmental samples but rarely from patients. The aim of the study was to represent isolation of unusual bacterial strains that could cause infection in patients. Final identification was performed using matrix-assisted description/ionization time-of-flight mass spectrometry (MALDI-TOF). Two isolates strains of E. aurantiacum were isolated, one isolate from distilled water used during surgical treatment and the second one from a patient with bacteremia after radical prostatectomy, both sensitive to all tested antimicrobials. Environmental strains could cause infection, especially in immunocompromised patients; therefore, rare bacteria testing is required, in which identification special assistance is provided by an automated system MALDI-TOF.

Host traits and evolution shape key coral-bacterial symbioses

The success of tropical scleractinian corals depends on their ability to establish symbioses with microbial partners. Host traits and evolution are known to shape the coral microbiome, but to what extent they affect its composition remains unclear. Here, by using twelve coral species representing the complex and robust clades, we show that functional traits and host evolutionary history explain 14% of the tissue and 13% of the skeletal microbiome composition, providing evidence that these predictors contribute to shaping the holobiont in terms of the presence and abundance of key bacterial species. Additionally, our study shows that the coral tissue and skeleton are dominated by rare bacteria and the skeleton can function as a microbial reservoir. Together, we provide novel insights into the processes driving coral-bacterial symbioses along with an improved understanding of the scleractinian tissue and skeleton microbiome.

Brassica napus phyllosphere bacterial composition changes with growth stage

Aims Phyllosphere bacteria play critical roles in plant growth promotion, disease suppression and global nutrient cycling but remain understudied. Methods In this project, we examined the bacterial community on the phyllosphere of eight diverse lines of Brassica napus for ten weeks in Saskatoon, Saskatchewan Canada. Results The bacterial community was shaped largely by plant growth stage with distinct communities present before and after flowering. Bacterial diversity before flowering had 111 core members with high functional potential, with the peak of diversity being reached during flowering. After flowering, bacterial diversity dropped quickly and sharply to 16 members of the core community, suggesting that the plant did not support the same functional potential anymore. B. napus line had little effect on the larger community, but appeared to have more of an effect on the rare bacteria. Conclusions Our work suggests that the dominant bacterial community is driven by plant growth stage, whereas differences in plant line seemed to affect rare bacteria. The role of these rare bacteria in plant health remains unresolved.

Identifying the Biogeographic Patterns of Rare and Abundant Bacterial Communities Using Different Primer Sets on the Loess Plateau

High-throughput sequencing is commonly used to study soil microbial communities. However, different primers targeting different 16S rRNA hypervariable regions often generate different microbial communities and result in different values of diversity and community structure. This study determined the consequences of using two bacterial primers (338f/806r, targeting the V3-V4 region, and 520f/802r, targeting the V4 region) to assess bacterial communities in the soils of different land uses along a latitudinal gradient. The results showed that the variations in the soil bacterial diversity in different land uses were more evident based on the former pair. The statistical results showed that land use had no significant impact on soil bacterial diversity when primer pair 520f/802r was used. In contrast, when primer pair 338f/806r was used, the cropland and orchard soils had significantly higher operational taxonomic units (OTUs) and Shannon diversity index values than those of the shrubland and grassland soils. Similarly, the soil bacterial diversity generated by primer pair 338f/806r was significantly impacted by mean annual precipitation, soil total phosphorus (TP), soil total nitrogen (TN), and soil available phosphorus (AVP), while the soil bacterial diversity generated by primer pair 520f/802r showed no significant correlations with most of these environmental factors. Multiple regression models indicated that soil pH and soil organic carbon (SOC) shaped the soil bacterial community structure on the Loess Plateau regardless of what primer pair was used. Climatic conditions mainly affected the diversity of rare bacteria. Abundant bacteria are more sensitive than rare bacteria to environmental changes. Very little of the variation in the rare bacterial community was explained by environmental factors or geographic distance, suggesting that the communities of rare bacteria are unpredictable. The distributions of the abundant taxa were mainly determined by variations in environmental factors.