Spiroplasma – an emerging arthropod-borne pathogen?

Abstract

Spiroplasma is a genus of wall-less, low-GC, small Gram-positive bacteria of the internal contractile cytoskeleton, with helical morphology and motility. The genus is classified within the class Mollicutes. Spiroplasma / host interactions can be classified as commensal, pathogenic or mutualist. The majority of spiroplasmas are found to be commensals of insects, arachnids, crustaceans or plants, whereas a small number of species are pathogens of plants, insects, and crustaceans. Insects are particularly rich sources of spiroplasmas. The bacteria are common in haematophagous arthropods: deerflies, horseflies, mosquitoes, and in ticks, where they may occur abundantly in salivary glands. The ability of spiroplasmas to propagate in rodents was experimentally proven, and Spiroplasma infections have been reported recently in humans. Some authors have purported an etiological role of Spiroplasma in causing transmissible spongiform encephalopathies (TSEs), but convincing proof is lacking. The possibility for humans and other vertebrates to be infected with Spiroplasma spp. in natural conditions is largely unknown, as well as the possibility of the transmission of these bacteria by ticks and haematophagous insects. Nevertheless, in the light of new data, such possibilities cannot be excluded.

Bacterial Associates of a Gregarious Riparian Beetle With Explosive Defensive Chemistry

“…Spiroplasma have been found to have commensal, mutualistic and/or pathogenic relationships with their plant and arthropod hosts (e.g., crustaceans, arachnids, insects). Insects most commonly infected with Spiroplasma include species of Odonata, Hemiptera, Hymenoptera, Diptera, Lepidoptera and Coleoptera ( Cisak et al, 2015 ). In Coleoptera, three species of Spiroplasma have been characterized from members of Scarabaeidae, Lampyridae, and Cantharidae ( Whitcomb et al, 1993 ; Hackett et al, 1996 ).…”

“…Spiroplasma has also been found in Tenebrionidae and Coccinellidae ( Tinsley and Majerus, 2006 ; Wang and Zhang, 2015 ). Different species of Spiroplasma have been shown (1) to be pathogens of honeybees ( Schwarz et al, 2014 ), (2) to cause reproductive manipulation in planthoppers and Drosophila ( Haselkorn, 2010 ; Sanada-Morimura et al, 2013 ), (3) to provide host defense against nematode-induced sterilization in Drosophila neotestacea ( Jaenike et al, 2010 ) and parasitoid wasps ( Xie et al, 2014 ), and (4) there are many Spiroplasma -host interactions in a wide variety of insects, crustaceans, and arachnids that are not well characterized ( Cisak et al, 2015 ). Future research is needed to determine whether Spiroplasma are mutualists, pathogens, or commensals in B. elongatulus .…”

Symbiont‐conferred reproduction and fitness benefits can favour their host occurrence

“…Indeed, recent years have seen a growing body of evidence on Wolbachia ‐associated fitness benefits (reviewed in Zug & Hammerstein, ). Spiroplasma is a wall‐less bacterium associated with diverse arthropods and plants in which it has commensal, pathogenic, or mutualistic effects (Cisak et al., ). Some Spiroplasma species and strains are known as male killers in fruit flies, ladybird beetles, planthoppers, and butterflies, wherein infected females produce all‐female or female‐biased offspring (Jiggins, Hurst, Jiggins, VD Schulenburg, & Majerus, ; Sanada‐Morimura, Matsumura, & Noda, ; Tinsley & Majerus, ; Williamson et al., ).…”

“…Indeed, recent years have seen a growing body of evidence on Wolbachia-associated fitness benefits (reviewed in Zug & Hammerstein, 2015). Spiroplasma is a wall-less bacterium associated with diverse arthropods and plants in which it has commensal, pathogenic, or mutualistic effects (Cisak et al, 2015).…”

Herbivore-Associated Bacteria as Potential Mediators and Modifiers of Induced Plant Defense Against Spider Mites and Thrips

“…Recent studies provide a growing body of evidence for Wolbachia -associated fitness benefits (for review, see Zug and Hammerstein, 2015 ). Also, other bacterial endosymbionts, such as Cardinium ( Weeks et al, 2003 ), Spiroplasma ( Cisak et al, 2015 ), or Rickettsia ( Weinert et al, 2009 ), ranked at decreasing prevalence in arthropods ( Duron et al, 2010 ), are similarly able to manipulate reproduction of their hosts ( Engelstädter and Hurst, 2009 ). These endosymbionts have been previously thought to be primarily vertically transmitted from mother to offspring but recent experimental evidence suggests that horizontal transmission via feeding on prey/hosts ( Le Clec’h et al, 2013 ; Ahmed et al, 2015 ), mating ( Moran and Dunbar, 2006 ), sharing hosts ( Huigens et al, 2004 ; Duron et al, 2010 ) and/or feeding on plants ( Caspi-Fluger et al, 2012 for Rickettsia ; Gonella et al, 2015 for Cardinium ; Li et al, 2017 for Wolbachia ) is probably more common than previously anticipated.…”