Illustration of Klebsiella pneumoniae bacteria linked to sacroiliac joint inflammation.

Uncommon Infection, Unexpected Culprit: How to Spot Klebsiella Sacroiliitis

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Beau Callahan in Health & Wellness October 2026 • 4 min read.

"A rare case highlights the importance of considering Klebsiella pneumoniae in sacroiliac joint infections, especially in diabetic patients."


Infective sacroiliitis, or septic arthritis of the sacroiliac joint, is a relatively rare condition, affecting only 1% to 2% of all patients with septic arthritis. It's a diagnostic puzzle, often mimicking other musculoskeletal issues like degenerative spine disease. The challenge lies in its varied symptoms and lack of clear indicators, leading to delays in proper diagnosis and treatment.

The usual suspects in these infections are gram-positive cocci, with staphylococci leading the pack. Gram-negative bacillus, Salmonella spp and Pseudomonas aeruginosa are most commonly encountered. However, Klebsiella pneumoniae is a less common culprit, typically popping up in specific situations like trauma, in neonates, elderly, intravenous drug abuser and immune-compromised patients.

Now, a recent case shines a light on an unexpected twist: a Klebsiella pneumoniae infection in the sacroiliac joint. This case emphasizes the importance of considering Klebsiella pneumoniae as a potential cause, particularly in individuals with diabetes.

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Klebsiella in a 25-Case Series

A retrospective study titled “Sacroiliites infectieuses dans le centre tunisien: étude rétrospective de 25 cas” reported several organisms among pyogenic sacroiliitis cases. Staphylococcus aureus accounted for 8 cases (57%) and Escherichia coli for 3 (22%). Klebsiella pneumoniae, Klebsiella oxytoca, and Pseudomonas aeruginosa were each reported in one case (7%).

Targeted Treatment in an Immunocompromised Patient

A 2024 case report on infectious sacroiliitis in immunocompromised patients describes diagnostic and treatment challenges. It highlights a minimum six-week course of targeted antibiotics to support bacterial eradication and prevent relapse. The snippet concerns these patients specifically and does not establish that this duration applies to every case.

The Case: When Diabetes Opens the Door

Illustration of Klebsiella pneumoniae bacteria linked to sacroiliac joint inflammation.

Consider the case of a 62-year-old woman with a history of poorly controlled diabetes. She presented with fever and feeling unwell for five days. On arrival, she had a high spiking fever and was biochemically in diabetic ketoacidosis. Initially, blood cultures revealed gram-negative bacilli, which were later identified as Klebsiella pneumoniae.

She initially responded well to intravenous antibiotics (Cefuroxime), hydration, and insulin. However, during the second week, she developed a gradual, dull ache in her right gluteal region, worsened by movement. This pain intensified, leaving her unable to walk due to the pain. Imaging revealed widening, erosion, and sclerosis of the right sacroiliac joint.

  • The Challenge of Diagnosis: Attempts to obtain a joint sample via CT guidance were unsuccessful. In the presence of Klebsiella pneumoniae bacteremia and consistent imaging, she underwent debridement and washout of the sacroiliac joint with gentamicin bone cement.
  • Treatment and Recovery: Samples from the procedure confirmed Klebsiella pneumoniae. She completed eight weeks of intravenous antibiotics, leading to a successful recovery.
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Limits in the Evidence Base

A multicentre study of 39 adults notes that most observations on infectious sacroiliitis are based on isolated case reports or small case series. The SANJO guideline reports that no clinical trials evaluate the total duration of antimicrobial treatment or the duration of intravenous and oral antibiotic treatment in adults with septic arthritis of native joints. Together, these sources point to limits in the available evidence for treatment-duration decisions.

CT’s Sensitivity and Role

The Klebsiella pneumoniae sacroiliac septic arthritis case report cites a patient series in which CT had low sensitivity for pyogenic sacroiliitis: only 40% of adult patients had positive findings. The report suggests CT is more suitable for detecting cortical bone destruction, particularly in elderly patients with osteoporosis who may develop such destruction early in the disease course. These figures and observations are reported in the cited case report’s discussion.

This case underscores that even in the absence of typical risk factors, Klebsiella pneumoniae should be considered, especially in those with diabetes.

Why This Matters: Recognizing the Uncommon

Non-brucellar and non-tuberculous infective sacroiliitis are rare, often masked by misleading symptoms. With only about 350 reported cases from 1878 to 2012, the condition is easily overlooked. Symptoms like lower back, gluteal, or hip pain can point to various issues, making diagnosis tricky.

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Rare Joint Infections in Adults

The cited report says septic arthritis of the knee or sacroiliac joint has been occasionally reported in adults, while septic arthritis of the hip joint (SAHJ) is rare. It states that K. pneumoniae-induced SAHJ had not been reported to date and presents a very rare case with successful treatment. The report’s rarity claim is specific to K. pneumoniae-induced SAHJ, not sacroiliitis.

Projected Septic Arthritis Trends

A market report expects the incidence of septic arthritis to continue to increase. It identifies increasing use of joint replacements as a major contributor to that expected rise. The snippet gives no numerical forecast and does not specify a projection for Klebsiella sacroiliitis in particular.

A Reported Klebsiella Case

A case report describes pyogenic septic arthritis of the sacroiliac joint caused by Klebsiella pneumoniae. Its authors present the case as one not previously reported in the literature. They highlight it as an important case of this infection.

While Staphylococcus aureus is often the main culprit in sacroiliac joint infections, it's crucial to remember that gram-negative organisms like Klebsiella pneumoniae can also be responsible, especially in specific populations. Therefore, treatment should cover a range of potential pathogens.

This case adds to the existing knowledge, emphasizing the need for clinicians to consider sacroiliac joint septic arthritis in patients with suggestive symptoms, particularly those with diabetes or other health-related infections. Early diagnosis and appropriate treatment are essential for preventing long-term complications and ensuring a full recovery.

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

Everything You Need To Know

1

What is infective sacroiliitis and why is it important?

Infective sacroiliitis is a rare condition, representing only 1% to 2% of septic arthritis cases. This makes it a diagnostic challenge, as it often presents symptoms similar to other musculoskeletal problems such as degenerative spine disease. Its rarity and ambiguous symptoms contribute to delays in diagnosis and treatment. The case highlights the importance of quick recognition to avoid potentially serious complications.

2

What is Klebsiella pneumoniae and why is it relevant in this context?

Klebsiella pneumoniae is a gram-negative bacterium that, in this context, caused sacroiliitis in a patient. This is significant because Klebsiella pneumoniae is not a common cause of this type of infection. The specific case involved a 62-year-old woman with poorly controlled diabetes, illustrating that this bacterium should be considered a possible cause, particularly in diabetic patients, even without the usual risk factors like trauma. The infection's presence required specific treatment and surgical intervention to resolve.

3

What is the sacroiliac joint and why is it important to this case?

The sacroiliac joint is the joint where the sacrum (the triangular bone at the base of the spine) meets the ilium (part of the pelvis). It is a relatively immobile joint designed to bear weight and absorb shock. An infection of this joint, known as infective sacroiliitis, is uncommon. The symptoms can be misleading, making diagnosis difficult. The case underscores that this joint infection can be caused by Klebsiella pneumoniae and highlights the need to consider this bacterium as a potential cause, especially in individuals with diabetes.

4

What were the challenges in diagnosing this specific case?

The diagnostic process faced challenges. The symptoms like fever, pain in the gluteal region, and difficulty walking can be misleading. The initial blood cultures revealed Klebsiella pneumoniae. The patient's condition improved with intravenous antibiotics (Cefuroxime), hydration, and insulin. However, imaging revealed widening, erosion, and sclerosis of the right sacroiliac joint. Attempts to get a joint sample failed, leading to debridement and washout of the sacroiliac joint with gentamicin bone cement. Samples confirmed the presence of Klebsiella pneumoniae. The complexity arises from the need to differentiate this rare condition from other more common issues and the necessity for invasive procedures to confirm the diagnosis.

5

What are the implications of this case for healthcare providers?

The implications are that healthcare providers must consider Klebsiella pneumoniae in patients with diabetes presenting with symptoms suggestive of sacroiliitis, even in the absence of typical risk factors. Early diagnosis and treatment are crucial to avoid prolonged illness and potential complications. The case emphasizes the importance of thorough investigations, including imaging and potentially joint aspiration/biopsy, to confirm the diagnosis and guide appropriate antibiotic therapy and, if needed, surgical intervention such as debridement and washout of the sacroiliac joint. Prompt and accurate diagnosis is vital in improving patient outcomes and reducing morbidity.

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