Doctors discovered a rare bloodstream infection caused by a bacteria normally found on skin in a healthy 50-year-old woman. The infection was unusual because it typically doesn’t cause serious illness. Researchers found that the patient had very low vitamin D levels and mouth sores, which may have allowed the bacteria to enter her bloodstream. When doctors gave her antibiotics and vitamin D supplements, she improved quickly. This case shows how vitamin D deficiency and damaged mouth tissue might work together to cause infections, and it demonstrates a new testing method that can detect hard-to-find bacteria.

The Quick Take

  • What they studied: A single patient with a rare bloodstream infection caused by a bacteria that normally lives harmlessly on skin, and what factors may have allowed this infection to develop.
  • Who participated: One 50-year-old woman with no serious health problems or medical implants who came to the hospital with fever and mouth sores.
  • Key finding: The patient had extremely low vitamin D levels (11.6 ng/mL, when normal is above 30) and mouth ulcers. These two problems together may have allowed a normally harmless skin bacteria to enter her bloodstream and cause infection.
  • What it means for you: This case suggests that vitamin D deficiency might increase infection risk, especially if you also have mouth sores or other damaged skin. While this is just one patient’s story, it highlights why maintaining healthy vitamin D levels may be important for immune health. However, this is not proof that low vitamin D causes infections in everyone.

The Research Details

This is a case report, which means doctors documented the medical story of one patient in detail. The patient was a 50-year-old woman who came to the hospital with recurring low-grade fever and painful sores in her mouth. Doctors used a special genetic testing method called metagenomic next-generation sequencing (mNGS) to identify the bacteria in her blood. This is like using a super-powerful microscope that can read the genetic code of tiny organisms, even when there are very few of them present. The doctors also did traditional blood cultures and blood tests to confirm the diagnosis and check for vitamin D levels.

This study matters because it shows how a new testing method (mNGS) can catch infections that older methods might miss. The bacteria in this case was so rare and grew so slowly that it might have been overlooked or thought to be contamination. By combining the new genetic test with traditional methods, doctors got a clear picture of what was happening. The case also suggests that vitamin D deficiency might be an important factor in allowing infections to develop, which could change how doctors think about preventing and treating certain infections.

This is a single case report, which is the lowest level of scientific evidence. It describes what happened to one person, not a large group. While the observations are detailed and well-documented, you cannot assume the same thing will happen to other people. The strength of this report is that multiple testing methods confirmed the diagnosis, and the patient’s improvement after treatment supports the doctors’ theory. However, because it’s just one case, the findings need to be studied in more patients before drawing firm conclusions.

What the Results Show

The patient presented with recurring low-grade fever and painful ulcers (sores) in her mouth. Blood tests showed she had a severe vitamin D deficiency with a level of 11.6 ng/mL (normal is above 30 ng/mL). The genetic sequencing test identified the rare bacteria Staphylococcus saccharolyticus in her blood at a level of 15%, meaning it made up a significant portion of the genetic material detected. This was confirmed by traditional blood culture methods. Her inflammation markers were very high, with C-reactive protein at 88.3 mg/L, indicating her body was fighting an infection. When doctors started her on an antibiotic called moxifloxacin and vitamin D supplements (2000 IU daily), her fever went away within five days, and her inflammation markers dropped dramatically to 12.0 mg/L.

An initial antibiotic (ceftriaxone) did not work, but switching to moxifloxacin was effective. This suggests the bacteria may have been resistant to the first antibiotic or that moxifloxacin was better at reaching the bacteria. The combination of treating the infection with antibiotics while also correcting the vitamin D deficiency appeared to work better than antibiotics alone might have. The patient’s mouth sores also improved as her overall infection resolved.

This bacteria is extremely rare in bloodstream infections, especially in healthy people without medical implants like artificial joints or heart valves. Previous cases have been documented, but they usually occur in people with weakened immune systems or implanted devices. This case is unusual because the patient was otherwise healthy, suggesting that vitamin D deficiency and mouth damage created a unique situation that allowed the infection to develop. The use of mNGS genetic testing is newer than traditional methods and appears to be more effective at finding rare bacteria.

This is a single case, so we cannot know if the same pattern would occur in other patients. We don’t know if vitamin D deficiency alone causes this infection, or if the mouth sores alone would have caused it—it may require both factors together. The patient’s exact source of infection is not completely clear. We also don’t know the long-term outcome or whether the infection could return. Finally, because this is so rare, we cannot do a controlled study comparing treatment approaches.

The Bottom Line

Based on this single case, there is no strong evidence to change medical practice for most people. However, the case suggests that maintaining adequate vitamin D levels (above 30 ng/mL) may be important for immune health. If you have mouth sores or other skin damage combined with symptoms like fever, see a doctor. If you are found to have very low vitamin D, correcting this deficiency appears to be important for overall health. Confidence level: Low (based on one case, not a large study).

This case is most relevant to doctors treating rare infections and patients with severe vitamin D deficiency. People with mouth sores, skin damage, or signs of infection should be aware that vitamin D status might matter. This is particularly important for people with weakened immune systems. However, this single case does not mean that everyone with low vitamin D will develop infections.

In this patient, fever resolved within five days of starting appropriate treatment, and inflammation markers improved significantly within the same timeframe. However, recovery timelines vary greatly depending on the individual and the specific infection.

Want to Apply This Research?

  • Track vitamin D levels quarterly through blood tests and log any mouth sores, skin damage, or fever episodes. Record vitamin D supplement intake daily to ensure consistency.
  • If your app shows low vitamin D levels, set a daily reminder to take vitamin D supplements as recommended by your doctor. If you develop mouth sores or other skin damage, log this in your health app and monitor for fever or other infection signs.
  • Establish a baseline vitamin D level through testing, then retest every 3 months if deficient. Track any infections or fever episodes in relation to vitamin D levels and supplement adherence. Share this data with your healthcare provider to identify patterns.

This case report describes one patient’s experience with a rare infection and is not medical advice. Vitamin D deficiency should be diagnosed and treated by a healthcare provider based on blood tests. If you have fever, mouth sores, or signs of infection, consult a doctor immediately. Do not self-treat with vitamin D supplements without medical guidance, as excessive vitamin D can be harmful. This single case does not prove that low vitamin D causes infections in other people. Always discuss your individual health situation with your healthcare provider before making changes to supplements or treatment.