Ignatzschineria indica Isolated From a Human Breast Abscess: A Rare Case

Abstract

Ignatzschineria indica is a gram-negative aerobic bacillus, usually isolated from the gut content of adult flesh flies or larvae of Wohlfahrtia magnifica. Ignatzschineria spp. associated with human infection is hypothesized to be related to maggot therapy. We are reporting the first case of Ignatzschineria indica isolated from a breast abscess, along with Proteus penneri and Providencia stuartii in a 76-year-old female. The patient presented with a left breast mass, weight loss, and normal vital signs; physical examination of the left breast showed a fungating mass with foul smelling draining necrotic tissue and a left axillary abscess. A biopsy was performed that revealed an invasive mammary carcinoma (mucinous type) with the tumor ulcerating the overlying skin. Additionally, a culture of the abscess yielded growth of gram-negative rods. The organism was identified as I. indica by 16S rRNA gene sequencing. Although the pathogenic capacity of the organism cannot be determined at this point, we are establishing the need for further study of patients with cultures positive for I. indica in order to understand the pathologic implications, and therapy to control this organism in human host.

A Case of Ignatzschineria indica Bacteremia following Maggot Colonization

“…Over the past 10 years, there have been a handful of cases reported where Ignatzschineria indica was considered to be pathogenic [ 2 , 4 – 7 ]. There are several similarities between case reports, predominantly wound infestation with maggots.…”

“…Finally, a female with a history of hypertension and diabetes presented with intense abdominal pain, constipation, and an elevated white blood cell count [ 7 ]. Physical examination revealed a left side fungating breast mass, malodorous necrotic tissue on the left nipple, and a left axillary abscess.…”

Ignatzschineria indica bloodstream infection associated with maggot infestation of a wound in a patient from Canada

“…Most clinical cases from Europe have described infection due to the species I. larvae and I. ureiclastica (9)(10)(11)13). In contrast, I. indica is the only species that has been reported in cases from the United States and Canada (8,12,14,15). All four Ignatzschineria spp have been isolated from the gut contents or larvae of flesh flies (Diptera: Sarcophagidae), but it remains unclear which fly larvae are predominantly associated with Ignatzschineria infections in humans (3,5).…”

“…In the published case reports of Ignatzschineria infection, various methods have been used for susceptibility testing, including disk diffusion, testing on an automated instrument (VITEK2), and ETEST (bioMérieux) (7,9,10). In some case reports, no details were provided on the method used for susceptibility testing, or susceptibility testing was not performed (7,8,11,13,15,17). The breakpoints used for interpretation of susceptibility data were also not always clearly indicated, although CLSI breakpoints for non-Enterobacteriaceae have been applied in at least one case as we elected to do here (8).…”

“…The breakpoints used for interpretation of susceptibility data were also not always clearly indicated, although CLSI breakpoints for non-Enterobacteriaceae have been applied in at least one case as we elected to do here (8). Despite these limitations, Ignatzschineria spp clinical isolates have generally been found to be susceptible to aminoglycosides, fluoroquinolones, and trimethoprim-sulfamethoxazole (8)(9)(10)(13)(14)(15)18). Many of the reported isolates have also tested susceptible to various β-lactams (Table 1), but resistance to third-generation cephalosporins, piperacillin-tazobactam, and carbapenems has been described (12).…”