Myiasis Associated Septicemia with Wohlfartiimonas: Innocent Bystander or Wolf in Sheep’s Clothing?

w magnifica flyThe recent issue of the U.S. Centers for Disease Control and Prevention’s (CDC) journal, Emerging Infectious Diseases (EID), has published a couple of cases of septicemia in two elderly people with Wohlfartiimonas chitiniclastica, of whom one had succumbed to the infection. This comes as an addition to a growing body of evidence about this rare infection, associated with the fly Wohlfartiimonas magnifica, which has been most commonly been associated with myiasis. Image Credit: CDC EID via Joaquim Alves Gaspar, Wikimedia Commons.


The article speaks about two cases of infection due to Wohlfartiimonas chitiniclastica, which is associated with the W. magnifica fly, commonly implicated in myiasis in neglected human beings. The case report states:

W. chitiniclastica is a short, gram-negative, facultative anaerobic, and motile gammaproteobacterium with strong chitinase activity. It was isolated from the homogenated third-stage larvae of the W. magnifica fly (1) (Figure). This fly has been reported as the cause of myiasis in live vertebrates in Spain, France, Hungary, Turkey, Egypt, Iran, and Korea (2); its distribution is known to be progressively expanding, in part because of its broad adaptation capacities. Reported cases of human bacteremia have been mainly from Europe and South America; patients included a 60-year-old homeless woman in southeastern France (3), a 70-year-old homeless man with alcoholism in Argentina (4), and an 82-year-old woman in the United Kingdom (5). A skin and soft tissue infection was reported in a child with orofacial gangrene (noma) in Niger (6), and an osteomyelitis case was reported in India (7). The northernmost region from which a case has been reported is Estonia, where a 64-year-old man with chronic foot gangrene was coinfected with W. chitiniclastica and Myroides odoratimimus (8). Cases from the United States include septicemia in a deer in Michigan (9) and a leg wound infection in a 26-year-old man in New York (10).

The two cases reported in the case are:

  • A 72 year old man, suffering from stroke and deafness, was found unconscious and unattended for 3 days, hypothermic, bradycardic, and hypotensive, with maggots crawling out of an umbilical wound. Anerobic and aerobic cultures grew Escherichia coli and Wohlfartiimonas chitiniclastica within 12 hours. He succumbed to the infection.
  • 69 year old homeless woman with hemiparesis following ruptured arterial aneurysm. She had sacral decubitus ulcers for which she underwent debridement. “The deep wound culture grew polymicrobial flora that included W. chitiniclastica, Staphylococcus aureus, Aeromonas spp., S. simulans, and Bacteroides fragilis. The anaerobic bottle from both blood cultures grew a gram-negative anaerobic bacillus, Anaerobiospirilum succinicproducens. In addition, Proteus mirabilis was isolated from a urine culture.”

The article goes on to conclude on a rather important note:

For the 2 patients in Hawaii, maggots were not collected, and we could not identify the specific fly species. In the first patient, W. chitiniclastica was clinically relevant because it was isolated from blood culture and maggots were observed in his wound. However, the coexisting E. coli infection may have played a critical role in the patient’s death. The second case was nonfatal, and we cannot determine the clinical relevance of W. chitiniclastica because it was isolated from a polymicrobial wound in which no maggots were observed and because A. succinicproducens was isolated from blood culture. Even so, these reports should help increase awareness of this specific type of infection related to myiasis in homeless and hygiene-deficient patients in the United States.

Reference:

Nogi M, Bankowski MJ, Pien FD. Wohlfahrtiimonas chitiniclastica in 2 elderly patients, Hawaii [letter]. Emerg Infect Dis. 2016 Mar [15th March, 2016]. http://dx.doi.org/10.3201/eid2203.151701

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