Streptococcus anginosus (Streptococcus milleri Group) Pyomyositis in a 50-Year-Old Man with Acquired Immunodeficiency Syndrome: Case Report and Review of Literature

Multiple Brain Abscesses due to Streptococcus anginosus: Prediction of Mortality by an Imaging Severity Index Score

An elderly patient with altered mental status, brain abscesses, ventriculitis, and empyemas died of septic shock and brain abscesses secondary to Streptococcus anginosus despite aggressive treatment. An imaging severity index score with a better prognostic value than the Glasgow coma scale predicted mortality in this patient.

Acquired torticollis due to primary pyomyositis of the paraspinal muscles in an 11-year-old boy

Torticollis is characterised by tilting and rotation of the cervical spine in opposite directions. Causes can be congenital or acquired. Primary pyomyositis is a rare subacute deep bacterial infection of skeletal muscles that typically affects individuals under 20 years of age from tropical countries. Infrequently, pyomyositis occurs in individuals from temperate regions, usually in immunocompromised adults, and this is defined as secondary pyomyositis. We report a case of acquired torticollis due to primary pyomyositis of the paraspinal muscles in a previously healthy boy from the UK. A prolonged course of antibiotics and physiotherapy led to a complete resolution of his illness. We review how to differentiate pyomyositis from focal myositis, a more common inflammatory muscular cause of acquired torticollis.

Solitary Pyomyositis of the Left Rhomboideus Muscle Caused byStreptococcus anginosusandStreptococcus intermediusin an Immunocompetent Person

Primary pyomyositis is a bacterial infection of the skeletal muscle commonly affecting children with Staphylococcus aureus most often isolated as a pathogen. However, pyomyositis caused by anaerobic bacteria is rare in adults. Here, we report a case of solitary Pyomyositis of the left rhomboideus muscle in an immunocompetent person. A 70-year-old Japanese male presented with high fever and left shoulder pain. His muscle below the lower edge of the left scapula was tender and swollen. His laboratory examinations revealed severe inflammation. Computed tomography showed a solitary low-density area around a contrast enhancement in the left rhomboideus muscle. He was diagnosed as having solitary pyomyositis. Although his symptoms did not improve despite empiric intravenous administration of antibiotics, an incision was performed. Streptococcus anginosus and Streptococcus intermedius were isolated from the culture of drainage fluid. His symptoms gradually disappeared after the incisional drainage and continuous administration of antibiotics. Pyomyositis did not recur after his discharge. To the best of our knowledge, this is the first report on anaerobic pyomyositis of the shoulder muscle.

An unusual case of Streptococcus anginosus group pyomyositis diagnosed using direct 16S ribosomal DNA sequencing

Bacteria belonging to the Streptococcus anginosus group (Streptococcus intermedius, Streptococcus constellatus and Streptococcus anginosus) are capable of causing serious pyogenic infections, with a tendency for abscess formation. The present article reports a case of S anginosus group pyomyositis in a 47-year-old man. The pathogen was recovered from one of two blood cultures obtained from the patient, but speciation was initially not performed because the organism was considered to be a contaminant (viridans streptococci group). The diagnosis was ultimately confirmed using 16S ribosomal DNA sequencing of purulent fluid obtained from a muscle abscess aspirate. The present case serves to emphasize that finding even a single positive blood culture of an organism belonging to the S anginosus group should prompt careful evaluation of the patient for a pyogenic focus of infection. It also highlights the potential utility of 16S ribosomal DNA amplification and sequencing in direct pathogen detection from aspirated fluid in cases of pyomyositis in which antimicrobial therapy was initiated before specimen collection.

Phylogenetic relationship and virulence inference of Streptococcus Anginosus Group: curated annotation and whole-genome comparative analysis support distinct species designation

Background

The Streptococcus Anginosus Group (SAG) represents three closely related species of the viridans group streptococci recognized as commensal bacteria of the oral, gastrointestinal and urogenital tracts. The SAG also cause severe invasive infections, and are pathogens during cystic fibrosis (CF) pulmonary exacerbation. Little genomic information or description of virulence mechanisms is currently available for SAG. We conducted intra and inter species whole-genome comparative analyses with 59 publically available Streptococcus genomes and seven in-house closed high quality finished SAG genomes; S. constellatus (3), S. intermedius (2), and S. anginosus (2). For each SAG species, we sequenced at least one numerically dominant strain from CF airways recovered during acute exacerbation and an invasive, non-lung isolate. We also evaluated microevolution that occurred within two isolates that were cultured from one individual one year apart.

Results

The SAG genomes were most closely related to S. gordonii and S. sanguinis, based on shared orthologs and harbor a similar number of proteins within each COG category as other Streptococcus species. Numerous characterized streptococcus virulence factor homologs were identified within the SAG genomes including; adherence, invasion, spreading factors, LPxTG cell wall proteins, and two component histidine kinases known to be involved in virulence gene regulation. Mobile elements, primarily integrative conjugative elements and bacteriophage, account for greater than 10% of the SAG genomes. S. anginosus was the most variable species sequenced in this study, yielding both the smallest and the largest SAG genomes containing multiple genomic rearrangements, insertions and deletions. In contrast, within the S. constellatus and S. intermedius species, there was extensive continuous synteny, with only slight differences in genome size between strains. Within S. constellatus we were able to determine important SNPs and changes in VNTR numbers that occurred over the course of one year.

Conclusions

The comparative genomic analysis of the SAG clarifies the phylogenetics of these bacteria and supports the distinct species classification. Numerous potential virulence determinants were identified and provide a foundation for further studies into SAG pathogenesis. Furthermore, the data may be used to enable the development of rapid diagnostic assays and therapeutics for these pathogens.

Streptococcus milleri Group Cutaneous Abscess Associated with Insulin Injection to Distal Lower Extremity in an Insulin-Dependent Diabetic Man

Purpose

We report a case of Streptococcus milleri group (SMG)-associated cutaneous abscess in an older diabetic man. The infection developed after subcutaneous insulin injection to the distal lower extremity. This is the first known account of SMG-associated abscess secondary to insulin administration.

Summary

A 60-year-old Caucasian insulin-dependent diabetic male developed a severe cutaneous infection including abscess and surrounding cellulitis at the site of a self-administered insulin glargine injection on the medial portion of his right lower leg. The infection developed rapidly within 1 day following the injection. Cultures from purulent drainage were positive for SMG. The infection resolved rapidly with an antibiotic regimen including 1 dose of clindamycin followed by intravenous pipercillin/tazobactam plus vancomycin and concluded with outpatient treatment with sulfamethoxazole/trimethoprim. Organisms belonging to SMG are increasingly recognized as pyogenic pathogens responsible, most commonly, for abscess infections. SMG infections have been reported in diabetics; however, this is the first known case of SMG-associated abscess secondary to subcutaneous insulin administration.

Conclusion

A 60-year-old diabetic male experienced a severe SMG-associated abscess in the distal lower extremity after self-injection with insulin glargine. The infection resolved rapidly with intravenous and oral antibiotics. Clinicians should be aware of the potential for abscess infection from SMG at insulin injection sites.

Pyomyositis

Pyomyositis is the primary infection of the skeletal muscle. It is common in the tropics, but is increasingly being reported worldwide. It can affect immunocompromised and immunocompetent individuals. Staphylococcus aureus is the most common causative organism. Muscle histology and its culture remain the gold standard for diagnosis. However, among noninvasive methods, MR imaging is highly sensitive and can image large areas of the body and detect subclinical involvement. Early diagnosis, institution of appropriate antibiotic therapy, and drainage of pus lead to favorable outcome.