Inspired by Xiao et al 2022.
DM – diabetes mellituskey to acronyms
T6SS – type VI secretion system
T3SS – type III secretion system
CT – computed tomography
TB – tuberculosis
MRI – magnetic resonance imaging
IV – intravenous
Also known as Pseudomonas pseudomallei, sure enough this Gram-negative, bipolar, aerobic, motile, rod bacterium appears in my undergraduate microbiology textbook from the 1980’s. Although clearly it escaped my attention, along with quite a few other opportunistic pathogens that most of us never come across in practice.
This is the first report of infection with Burkholderia pseudomallei associated with acupuncture. The bug is a soil dwelling bacterium from tropical and subtropical regions, but its territory is thought to have expanded as a result of severe weather events and environmental disasters. That territory includes southern China, and whilst this case report comes from Nanjing, which translates as southern capital, it is a good halfway up the country, sitting west of Shanghai about 300 km along the Yangtze river.
This pathogen is important enough to have a specific disease named for it – Melioidosis, and it is said to have a mortality of 10–50%. A publication from 2016 estimated that there are about 165 000 cases per year, most going unreported, with 89 000 resulting in death. That is a little more than 50%!
Both humans and animals can be infected with Burkholderia pseudomallei, and naturally acquired infections occur via expose to contaminated water through broken skin, inhalation or ingestion. Melioidosis, symptomatic acute or chronic (>2 months) infection with Burkholderia pseudomallei, is particularly associated with diabetes mellitus (DM) – 23% to 60% of patients with melioidosis also have DM. Cell mediated immune responses are reduced in DM, in particular the capacity of macrophages to phagocytose and kill the bacteria.
Burkholderia pseudomallei is an intracellular pathogen with a variety of virulence factors including T6SS, a molecular system like an inverted bacteriophage that can inject effector substances from within its own cytoplasm across both its own cell membrane and that of a target cell. A similar mechanism (T3SS) is used by the bacteria to escape from inside a phagosome into the cytoplasm of the phagocytic host cell, where it can replicate.
In this case, a 49-year-old man with undiagnosed DM presented with a one-month history of fever, mostly low grade but with one episode reaching 40oC. CT scans at his local hospital suggested bilateral pleural effusions and lung nodules, and after a failure of initial antibiotic treatment, a diagnosis of TB was considered, and he was transferred to a specialist unit in Nanjing. Treatment for TB was initiated until the blood culture from his local hospital revealed Burkholderia pseudomallei infection. The lung nodules were then considered to be secondary to spread via the bloodstream and the hunt was on for the original source of the infection. The patient’s continued complaints of back pain and history of lumbar disc prolapse led to lumbar spine MRI, which revealed extensive subcutaneous paravertebral abscesses.
Investigation of the patient’s medical history subsequently revealed that he had undergone acupuncture treatment for his back pain a week prior to the onset of his fever. It seems reasonable to assume that the infection resulted from inoculation with acupuncture needles, and that his skin was contaminated with the bug. The authors of the report assumed that the acupuncture needles were ‘carelessly exposed to tap water’. I think it is more likely that the bug was inoculated from deep in the skin layer where the alcohol disinfectant did not reach.
After 2 weeks of IV meropenem he was discharged home on oral antibiotics, but he did not continue taking them and the infection recurred five and a half months after discharge. He was treated again with IV meropenem for 12 days and his blood glucose was brought under control. He was discharged on oral levofloxacin and followed up after three months.
Apparently this bug has survived for more than 16 years in distilled water, and it is thought to be able to enter a dormant state and evade immune surveillance. Reactivation after 19 to 29 years has been reported, but a claim of 62 years in a former World War II prisoner of war was not supported by genomic sequencing of cases in the Western hemisphere.
1 Xiao L, Zhou T, Chen J, et al. Paravertebral abscess and bloodstream infection caused by Burkholderia pseudomallei after acupuncture: a case report. BMC Complement Med Ther 2022;22:95. doi:10.1186/s12906-022-03563-8
2 Currie BJ, Dance DAB, Cheng AC. The global distribution of Burkholderia pseudomallei and melioidosis: an update. Trans R Soc Trop Med Hyg 2008;102 Suppl 1:S1-4. doi:10.1016/S0035-9203(08)70002-6
3 Wiersinga WJ, Virk HS, Torres AG, et al. Melioidosis. Nat Rev Dis Primer 2018;4:17107. doi:10.1038/nrdp.2017.107
4 Cheng AC, Currie BJ. Melioidosis: epidemiology, pathophysiology, and management. Clin Microbiol Rev 2005;18:383–416. doi:10.1128/CMR.18.2.383-416.2005
5 Limmathurotsakul D, Golding N, Dance DAB, et al. Predicted global distribution of Burkholderia pseudomallei and burden of melioidosis. Nat Microbiol 2016;1:15008. doi:10.1038/nmicrobiol.2015.8
6 Pumpuang A, Chantratita N, Wikraiphat C, et al. Survival of Burkholderia pseudomallei in distilled water for 16 years. Trans R Soc Trop Med Hyg 2011;105:598–600. doi:10.1016/j.trstmh.2011.06.004
7 Gee JE, Gulvik CA, Elrod MG, et al. Phylogeography of Burkholderia pseudomallei Isolates, Western Hemisphere. Emerg Infect Dis 2017;23:1133–8. doi:10.3201/eid2307.161978