science

Streptobacillus moniliformis

Streptobacillus moniliformis is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Streptobacillus moniliformis rather than just read about it. In short: Streptobacillus moniliformis is a non-motile, Gram-negative rod-shaped bacterium that is a member of the family Leptotrichiaceae. The genome of S. moniliformis is one of two completed sequences of the order Fusobacteriales.

Key takeaways

Streptobacillus moniliformis belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Streptobacillus moniliformis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Streptobacillus moniliformis from memory before moving on to harder problems.

Reference excerpt

Streptobacillus moniliformis is a non-motile, Gram-negative rod-shaped bacterium that is a member of the family Leptotrichiaceae. The genome of S. moniliformis is one of two completed sequences of the order Fusobacteriales.

Etymology Its genus name comes from the Ancient Greek word στρεπτός : streptós for "curved" or "twisted", and the Latin word bacillus meaning "small rod." The specific name moniliformis means "necklace like". S. moniliformis is microaerophilic, requiring less oxygen than is present in the atmosphere for its growth.

Background

History S. moniliformis was first isolated from a rat-bitten man in 1914 by German microbiologist H. Schottmüller, who described it as Streptothrix muris ratti. In the United States during the year 1916, S. moniliformis was determined to be the causative source of rat-bite fever.

Microbiology Some isolates of S. moniliformis have been collected from the upper respiratory tract of domestic and wild rats. Two known variants of S. moniliformis have been identified. The bacillary type is pathogenic. In contrast, the spontaneously occurring L-form, which lacks a cell wall and whose colonies grow in a "fried egg" formation, is non-pathogenic.

Morphology The bacterium S. moniliformis is a gram-negative pleomorphic rod occurring frequently in chains and tangled filaments with bulbous or Monilia-like swellings. The organism presents phenotypically as being facultatively anaerobic, non-motile, weakly ferments glucose and maltose, is catalase and oxidase-negative, does not reduce nitrate, and exhibits no growth on MacConkey agar. Morphologically, colonies of S. moniliformis are 1–2 mm in size, smooth, convex, non-hemolytic (varied presentation with an α-hemolysis is not uncommon) and gray in color. When cultured in broth, a typical "puff-ball" appearance is seen.

Taxonomy Streptobacillus moniliformis was previously classified under the family Fusobacteriaceae. It was later regrouped with three other genera: Sebaldella, Sneathia, and Leptotrichia. These four genera were classified under the family Leptotrichiaceae following comparative analyses of the 16S ribosomal RNA gene sequences and 16S-23S rDNA internal transcribed spacer sequences among members of the phylum Fusobacteria. Identification of conserved signature indels unique to Fusobacteria and its primary clades as well as phylogenetic analysis of members of Fusobacteria based on concatenated sequences of 17 conserved proteins further support the distinction between the two families. S. moniliformis was formerly classified as the only member of the genus Streptobacillus. However, Streptobacillus strains HKU33T and HKU34 were isolated in Hong Kong in September 2014. Streptobacillus HKU33T was found in pus isolated from the abscess of a 38-year-old patient with quinsy and HKU34 from the elbow joint fluid of a 64-year-old patient with septic arthritis. Following analysis of the 16S rRNA gene sequences found in members of Leptotrichiaceae and partial sequences of the recA, groEl, and gyrB genes present in both isolates, the two strains were taxonomically grouped under the novel species Streptobacillus hongkongensis sp. nov.

Genomics The U.S. Department of Energy's Joint Genome Institute (DOE JGI) sequenced the complete genome of S. moniliformis DSM 12112. It is made up of one circular chromosome of 1,673,280 base pairs as determined from a combination of Sanger and 454 sequencing. The mol% of guanine and cytosine in the DNA is 26.3% with 1,511 protein coding genes out of the 1,566 genes predicted. These low G+C values were previously only seen in members of the order Mycoplasmatales, which includes the genus Mycoplasma, indicating a relationship between Mycoplasma and S. moniliformis. However, 16S rRNA gene analysis showed this relation to be incorrect. S. moniliformis also has a single circular plasmid pSMON01 that is 10,702 base pairs long with 1,511 protein coding genes.

Isolation and identification The fastidious nature of Streptobacillus moniliformis makes it difficult to culture, with current published recommendations stating it requires media supplemented with 20% serum, ascitic fluid, or whole blood in order to grow. Numerous published reports also state that the organism is inhibited by the polyanionic detergent sodium polyanethole sulfonate (SPS-trade name; Liquoid; Hoffman-La Roche, Inc., Nutley, N.J.), the main anticoagulant in modern commercially available blood culture bottles, used in automated continuous blood culture instruments. Optimizing the best chances for organism recovery should include the aseptic collection of blood or sterile body fluids into commercial blood culture bottles (documenting the amount of blood drawn from the patient, if applicable) during the acute phase of infection, and collected in duplicate with optimal volumes of inoculation for the isolation and growth of S. moniliformis being 10 ml for adolescent to adult patients. In a pediatric population, 4–5 ml should be extrapolated. Bottles should be incubated minimally for 7 days to ensure the best chance for organism recovery when working with low levels of bacteremia. If not yet detected by day 7, they should be blind sub-cultured to rule out a false-negative blood culture result. Automated continuous blood culturing instrumentation growth and fluorescent detection data should be checked manually during the course of incubation in order to rule out missed false-negative samples. Once a bottle shows signs of organism growth and detection, a Gram stain should be performed followed by inoculation of blood onto rabbit or sheep blood agar and brain heart infusion broth and incubated aerobically at 35 °C, 35–37 °C, or 5% CO2 enriched (microaerophilic) environment for a minimum of 3–4 days. While the organism has been reported to be inhibited by specific blood culture additives, specifically SPS in the clinical lab, current research has proposed methods to overcome this limitation with "100% culture, growth success rates". According to Szewc et al., their research into the "reported" fastidious nature of S. moniliformis, and its inhibition by the anticoagulant SPS showed, that when using a specific volume of blood for inoculum, it resulted in 100% recovery and successful growth of this organism and appeared to overcome the inhibitions and limitations that historically have been observed when using SPS for blood culturing and recovering S. moniliformis in a clinical setting.

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Illustrations

Worked examples

Example 1 — a first encounter with Streptobacillus moniliformis

Start with the simplest possible case. Write down what Streptobacillus moniliformis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Streptobacillus moniliformis before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Streptobacillus moniliformis ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Streptobacillus moniliformis

In research: Streptobacillus moniliformis appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Streptobacillus moniliformis in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Streptobacillus moniliformis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fusobacteriota, Pathogenic bacteria, so understanding it makes those chapters shorter.
In everyday life: Look for Streptobacillus moniliformis outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Streptobacillus moniliformis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Streptobacillus moniliformis means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Streptobacillus moniliformis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Streptobacillus moniliformis in simple terms?

Why does Streptobacillus moniliformis matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Streptobacillus moniliformis?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Streptobacillus moniliformis.