Mycoplasma phocimorsus sp. nov., isolated from Scandinavian patients with seal finger or septic arthritis after contact with seals.

Seal finger (sealer's finger, spekk finger), an extremely painful hand infection contracted by individuals handling seals, has previously been associated with Mycoplasma phocacerebrale. From 2000 to 2014, six independent strains of a novel Mycoplasma species were isolated at Statens Serum Institut, Denmark, from Scandinavian patients with seal finger (M5725T, M6447, M6620, M6642 and M6879) or septic arthritis (M6921). Prior to the onset of infection, all patients had reported contact with unspeciated seals. All isolates grew within 2-5 days in Friis' modified broth and metabolized glucose and arginine but not urea. Strains M5725T, M6447, M6642 and M6921 also grew in Hayflick-type media. Colonies on agar media were large (0.5-1.0 mm) and had a typical 'fried egg' appearance, reduced tetrazolium, and were digitonin sensitive. Growth occurred at 32 °C but not at 42 °C. Strains were susceptible to doxycycline and moxifloxacin but resistant to azithromycin and erythromycin. The genomes of the six strains were sequenced and relatedness to all known Mycoplasma species was inferred. Phylogenetic analyses using 16S rRNA gene sequences and core genome single nucleotide polymorphisms showed that the isolated strains were highly similar and phylogenetically distinct from all other species within the genus Mycoplasma. The sizes of the genome sequences of the strains ranged from 744 321 to 772409 bp, with a G+C content of 25.0-25.2 mol%. Based on these analyses, we propose a novel species of the genus Mycoplasma with the name Mycoplasma phocimorsus sp. nov. with the first isolate M5725T (NCTC 14922T=DSM 116188T) as the proposed type strain and representative strains M6447, M6620, M6642, M6879 and M6921.

Sialidase and N-acetylneuraminate catabolism in nutrition of Mycoplasma alligatoris.

The contribution of N-acetylneuraminate scavenging to the nutrition of Mycoplasma alligatoris was examined. The wild-type grew substantially faster (P<0.01) than the mutant strains that were unable either to liberate (extracellular NanI- mutants) or to catabolize (NanA- mutants) N-acetylneuraminate from glycoconjugates in minimal SP-4 medium supplemented only with serum, but the growth of sialidase-negative mutants could not be restored to wild-type rate simply by adding unconjugated sialic acid to the culture medium. In 1 : 1 growth competition assays the wild-type was recovered in >99-fold excess of a sialidase-negative mutant after co-culture on pulmonary fibroblasts in serum-free RPMI 1640 medium, even with supplemental glucose. The advantage of nutrient scavenging via this mechanism in a complex glycan-rich environment may help to balance the expected selective disadvantage conferred by the pathogenic effects of mycoplasmal sialidase in an infected host.

Cellular Microbiology of Mycoplasma canis.

Mycoplasma canis can infect many mammalian hosts but is best known as a commensal or opportunistic pathogen of dogs. The unexpected presence of M. canis in brains of dogs with idiopathic meningoencephalitis prompted new in vitro studies to help fill the void of basic knowledge about the organism's candidate virulence factors, the host responses that it elicits, and its potential roles in pathogenesis. Secretion of reactive oxygen species and sialidase varied quantitatively (P < 0.01) among strains of M. canis isolated from canine brain tissue or mucosal surfaces. All strains colonized the surface of canine MDCK epithelial and DH82 histiocyte cells and murine C8-D1A astrocytes. Transit through MDCK and DH82 cells was demonstrated by gentamicin protection assays and three-dimensional immunofluorescence imaging. Strains further varied (P < 0.01) in the extents to which they influenced the secretion of tumor necrosis factor alpha (TNF-α) and the neuroendocrine regulatory peptide endothelin-1 by DH82 cells. Inoculation with M. canis also decreased major histocompatibility complex class II (MHC-II) antigen expression by DH82 cells (P < 0.01), while secretion of gamma interferon (IFN-γ), interleukin-6 (IL-6), interleukin-10 (IL-10), and complement factor H was unaffected. The basis for differences in the responses elicited by these strains was not obvious in their genome sequences. No acute cytopathic effects on any homogeneous cell line, or consistent patterns of M. canis polyvalent antigen distribution in canine meningoencephalitis case brain tissues, were apparent. Thus, while it is not likely a primary neuropathogen, M. canis has the capacity to influence meningoencephalitis through complex interactions within the multicellular and neurochemical in vivo milieu.

Identification of a Novel Mycoplasma Species in a Patient With Septic Arthritis of the Hip and Seal Finger.

An Alaska Native hunter developed fever, swollen finger, and septic hips after harvesting seals. Evaluation of hip tissue by 16S rRNA gene polymerase chain reaction and sequencing revealed a putative novel mycoplasma species. We report the identification of this organism and describe the first known case of disseminated seal finger mycoplasmosis.

Complete Sequence and Annotation of the Mycoplasma phocirhinis Strain 852T Genome.

The genome of Mycoplasma phocirhinis strain 852T was examined for determinants of tropism or virulence. It encodes multiple orthologs of an immunosuppressor that may predispose susceptibility to infection or influence outcomes of intercurrent diseases in marine mammals.

Complete Sequence and Annotation of the Mycoplasma phocicerebrale Strain 1049T Genome.

The Mycoplasma phocicerebrale genome was analyzed to better understand this opportunistic pathogen. Amplification with ϕ29 polymerase was used to generate enough genomic DNA for large-insert library construction. Like other mycoplasmas from seals, M. phocicerebrale encodes an immunosuppressor that may predispose susceptibility to infection or influence intercurrent diseases of affected hosts.

Complete Sequence and Annotation of the Mycoplasma phocidae Strain 105T Genome.

The genome of Mycoplasma phocidae strain 105T was analyzed in order to improve our understanding of its role in epidemic marine mammal mortalities. It was found to encode a suite of immunosuppressors that may enable evasion of host defenses and modulate susceptibility to viral coinfections or their severity in seals.

Complete Genome Sequence of Mycoplasma synoviae Strain WVU 1853T.

A hybrid sequence assembly of the complete Mycoplasma synoviae type strain WVU 1853(T) genome was compared to that of strain MS53. The findings support prior conclusions about M. synoviae, based on the genome of that otherwise uncharacterized field strain, and provide the first evidence of epigenetic modifications in M. synoviae.