Streptococcus intermedius causing infective endocarditis and abscesses: a report of three cases and review of the literature

Tran, MaryAnn P; Caldwell-McMillan, Molly; Khalife, Walid; Young, Vincent B.

doi:10.1186/1471-2334-8-154

Cited by 76 publications

(85 citation statements)

References 33 publications

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“…7 Similar to the recommendations for the management of brain abscess, which may frequently be polymicrobial, initial antibiotic therapy with ceftriaxone and metronidazole was administered. In most reported cases, patients underwent surgical abscess drainage together with antibiotic treatment.…”

Section: Case Reportmentioning

confidence: 99%

Diffusion-Weighted MR Imaging of Intramedullary Spinal Cord Abscess: Fig 1.

Dörflinger-Hejlek¹,

Kirsch²,

Reiter³

et al. 2009

AJNR Am J Neuroradiol

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SUMMARY:Early diagnosis and prompt initiation of adequate treatment are essential for clinical outcome in ISCA. We report a case in which DWI provided a more specific diagnosis than conventional MR imaging and allowed differentiation of a ring-enhancing lesion from intramedullary tumor. Diagnosis was proved by PCR from CSF (Streptococcus intermedius). Adequate antibiotic treatment was immediately initiated, and the patient recovered completely.ABBREVIATIONS: ADC ϭ apparent diffusion coefficient; DWI ϭ diffusion-weighted imaging; Gd ϭ gadolinium; ISCA ϭ intramedullary spinal cord abscess; PCR ϭ polymerase chain reaction I SCA is a rare entity that was first described by Hart in 1830, 1 and until now, to our knowledge, Ͻ100 cases have been reported in the literature. The early clinical suspicion and radiologic diagnosis are mandatory to start appropriate medical or surgical treatment and to avoid irreversible spinal cord damage. The radiologic technique of first choice is unambiguously MR imaging with intravenous Gd-chelates application, but differentiation from intramedullary tumors may be difficult. Case ReportA 80-year-old female patient with diabetes mellitus had been admitted with thoracic back pain after a collapse 2 days before. Other complaints were weakness in both legs, headache, and urinary incontinence.The clinical examination revealed slightly elevated body temperature (37.8°C), local tenderness along the thoracic spine, monoparesis, and hypoesthesia of the left leg below the T7 level and a positive Babinski sign on the left side. Blood tests at admission showed the following values: increased leukocytes of 16,700/L, an erythrocyte sedimentation rate of 16 mm/h, and moderately elevated C-reactive protein (69.5 mg/L). Findings of repeated blood and urine cultures were negative.Unremarkable conventional radiographs of the thoracic spine were followed by conventional MR imaging (including intravenous Gd-chelates application), which did not show any signs of contusion or fracture in the thoracic vertical bodies but did show an edema of the spinal cord extending from level T4 to T12 and a focal ring-enhancing lesion on level T8 with central necrosis and a diameter of 2 cm ( Fig 1A, -B). On T2-weighted images, the hypointense rim of the lesion could be delineated (Fig 1B). To differentiate an abscess from a tumor, we performed additional DWI with an axial and sagittal single-shot echo-planar spin-echo sequence. The images were acquired with b-values of 0 and 1000 s/mm 2 . The cavity of the lesion appeared strongly hyperintense on DWI and showed low ADCs on the ADC map compared with the myelon above and below the lesion, suggesting an intraspinal abscess (Fig 1C, -D). Lumbar puncture yielded the following values: white blood cells, 466/L; protein, 800 mg/L; and lactate, 4.7 mmol/L. CSF microscopy found predominantly polynuclear white blood cells but no tumor cells. Results of CSF Gram stain and culture were negative. PCR from CSF yielded deoxyribonucleic acid of Streptococcus intermedius. Therapy was initiat...

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Section: Case Reportmentioning

confidence: 99%

Diffusion-Weighted MR Imaging of Intramedullary Spinal Cord Abscess: Fig 1.

Dörflinger-Hejlek¹,

Kirsch²,

Reiter³

et al. 2009

AJNR Am J Neuroradiol

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“…It had been believed that deep-seated abscesses caused by AGS, including S. intermedius, are uncommon in healthy individuals without any identifiable risk factors such as immunocompromised states caused by diabetes, cirrhosis, and cancer (42)(43)(44). However, some reports have shown that S. intermedius can form deep-seated abscesses in the brain, lung, and spleen in healthy humans (45)(46)(47). It is important to analyze whether clinical isolates from such cases show high-ILY-producing phenotypes associated with lacR mutation.…”

Section: Discussionmentioning

confidence: 99%

LacR Mutations Are Frequently Observed in Streptococcus intermedius and Are Responsible for Increased Intermedilysin Production and Virulence

et al. 2013

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e Streptococcus intermedius secretes a human-specific cytolysin, intermedilysin (ILY), which is considered to be the major virulence factor of this pathogen. We screened for a repressor of ily expression by using random gene disruption in a low-ILY-producing strain (PC574). Three independent high-ILY-producing colonies that had plasmid insertions within a gene that has high homology to lacR were isolated. Validation of these observations was achieved through disruption of lacR in strain PC574 with an erythromycin cassette, which also led to higher hemolytic activity, increased transcription of ily, and higher cytotoxicity against HepG2 cells, compared to the parental strain. The direct binding of LacR within the ily promoter region was shown by a biotinylated DNA probe pulldown assay, and the amount of ILY secreted into the culture supernatant by PC574 cells was increased by adding lactose or galactose to the medium as a carbon source. Furthermore, we examined lacR nucleotide sequences and the hemolytic activity of 50 strains isolated from clinical infections and 7 strains isolated from dental plaque. Of the 50 strains isolated from infections, 13 showed high ILY production, 11 of these 13 strains had one or more point mutations and/or an insertion mutation in LacR, and almost all mutations were associated with a marked decline in LacR function. These results strongly suggest that mutation in lacR is required for the overproduction of ILY, which is associated with an increase in pathogenicity of S. intermedius. Streptococcus intermedius is a facultatively anaerobic member of the normal flora of the human oral cavity and the upper respiratory, gastrointestinal, and female urogenital tracts. S. intermedius belongs to the Anginosus group of streptococci (AGS), which also includes Streptococcus anginosus and Streptococcus constellatus (1, 2). AGS tend to form local suppurative infections, and these organisms are the most common pathogens associated with bacterial intracerebral abscesses (1-6). S. intermedius is the most pathogenic species of AGS and a leading cause of deepseated, serious purulent infections, including brain and liver abscesses (1, 2). This pathogen secretes a human-specific cytolysin, intermedilysin (ILY), which was originally identified in studies using an S. intermedius strain, UNS46, isolated from a human liver abscess (7). ILY is a member of the cholesteroldependent cytolysin (CDC) family and is considered the major virulence factor for infectivity and cytotoxicity toward human cells by S. intermedius (8-11). Therefore, investigation of the mechanisms that regulate ily expression could help elucidate how S. intermedius mediates its pathogenicity by controlling the amount of ILY secreted. To date, two factors have been reported to control the expression of ily. The first is autoinducer 2 (AI-2) (a LuxS product used by several bacteria in quorum-sensing signaling), which is reported to be an exponential-growth-phase-specific activator of ily transcription (12). In addition, we recently revealed th...

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“…Streptococcus intermedius is a member of the Streptococcus anginosus group (SAG). Several retrospective reviews and case reports have mentioned S. intermedius as a significant pathogen among the SAG species in the development of brain abscess (2)(3)(4)(5). However, no studies have compared S. intermedius brain abscess with abscess caused by other SAG members or other bacteria.…”

Section: Introductionmentioning

confidence: 99%

Culture-negative Brain Abscess with <i>Streptococcus intermedius</i> Infection with Diagnosis Established by Direct Nucleotide Sequence Analysis of the 16S Ribosomal RNA Gene

et al. 2012

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A 70-year-old woman developed a headache for a month followed by right upper limb weakness. CT scan and MRI showed multiple ring-enhancing lesions. An intracerebral aspiration of an abscess was performed, but culture results were negative. The nucleotide sequence analysis of the 16S rRNA gene from the specimens identified Streptococcus intermedius. Given this result, S. intermedius was cultured by enrichment culture, and its sensitivities to antibiotics were determined. The patient exhibited complete remission. Thus, 16S rRNA gene analysis was highly useful not only for pathogen identification with negative culture results but also for the appropriate selection of antibiotics.

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Streptococcus intermedius causing infective endocarditis and abscesses: a report of three cases and review of the literature

Cited by 76 publications

References 33 publications

Diffusion-Weighted MR Imaging of Intramedullary Spinal Cord Abscess: Fig 1.

Diffusion-Weighted MR Imaging of Intramedullary Spinal Cord Abscess: Fig 1.

LacR Mutations Are Frequently Observed in Streptococcus intermedius and Are Responsible for Increased Intermedilysin Production and Virulence

Culture-negative Brain Abscess with <i>Streptococcus intermedius</i> Infection with Diagnosis Established by Direct Nucleotide Sequence Analysis of the 16S Ribosomal RNA Gene

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