Ignatzschineria indica Bacteremia Initially Misdiagnosed in a Patient With a Maggot-Infested Wound

Design

Case presentation

A 72-year-old Caucasian man with a history of recurrent lower extremity cellulitis, homelessness, paroxysmal atrial fibrillation with poor medication adherence, and ongoing intravenous drug use presented to the emergency department with worsening pain in his left lower leg. He also experienced increasing nausea, vomiting, diarrhea, and confusion over the past six days. He had recently completed a course of cephalexin from a free clinic, which did not improve his condition, and initially declined emergency evaluation but came to the hospital as symptoms progressed.

On examination, a chronic wound on his left foot was noted to be infested with maggots. Erythema and swelling extended from the distal foot up to just below the knee, with significant tenderness and some purulent drainage. He was febrile with a temperature of 101.0°F. Cardiac monitoring and EKG confirmed atrial fibrillation with a rapid ventricular rate between 140 and 160 beats per minute. His respiratory rate was 22 breaths per minute, and oxygen saturation was adequate on room air. The patient was initially hypotensive (69/47 mmHg) but responded well to two liters of lactated Ringer’s solution, normalizing his blood pressure. His Glasgow Coma Scale was 14, with lethargy and occasional confusion, but he followed commands appropriately.

Laboratory results revealed leukocytosis with a white blood cell count of 18,000 cells/mm³ and thrombocytosis with platelets at 390,000 cells/µL. His creatinine was elevated at 1.48 mg/dL (baseline unknown), and lactic acid was 2.5 mg/dL. Inflammatory markers were elevated: C-reactive protein at 44 mg/dL and erythrocyte sedimentation rate at 54 mg/dL. Blood cultures were drawn on admission. A CT scan of the left lower extremity showed no evidence of osteomyelitis.

The patient was admitted for worsening cellulitis and started on broad-spectrum IV antibiotics, including vancomycin and piperacillin-tazobactam. He received two IV doses of metoprolol tartrate, which successfully resolved his atrial fibrillation; he was transitioned to daily oral metoprolol thereafter. Infectious disease and wound care teams were consulted.

After 24 hours, initial blood cultures suggested Corynebacterium jeikeium, but this was uncertain, so the sample was sent to a tertiary lab. Polymerase chain reaction (PCR) testing identified the pathogen as Ignatzschineria indica. Antibiotic susceptibility testing showed no significant resistance to common treatments. Based on these results, his antibiotics were de-escalated to oral levofloxacin.

After five days of treatment, the patient showed marked improvement: vital signs normalized, confusion and lethargy resolved, and erythema and swelling nearly disappeared. His heart rhythm remained stable in normal sinus rhythm after metoprolol treatment, and he was afebrile for over 24 hours before discharge. Discharge plans included outpatient wound debridement, continued wound care follow-up, infectious disease outpatient care, and an additional five days of oral levofloxacin.

Study Author Conclusions

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

Design

Case presentation

A 60-year-old homeless male presented to a tertiary hospital emergency department in Winnipeg during the summer with hypothermia and a reduced level of consciousness after being found unresponsive outdoors. On examination, he had a Glasgow Coma Scale score of 14, hypothermia at 34°C, atrial fibrillation with a heart rate of 170 beats per minute, and a large gangrenous wound on his left leg infested with maggots, along with scrotal swelling and cellulitis but no necrosis. Laboratory tests showed leukocytosis with neutrophilia, severe hyperglycemia, acute kidney injury, elevated creatine kinase, acidosis with elevated lactate, and imaging revealed gas in the soft tissues of the left leg without evidence of osteomyelitis or pelvic abscess. A central line was placed in the right internal jugular vein, and he was treated with intravenous lactated Ringer’s solution for volume resuscitation, external forced-air warming, and insulin to correct hyperglycemia.

He received empiric intravenous antibiotic therapy with piperacillin–tazobactam and vancomycin. Surgical irrigation and debridement of the left leg were performed; however, some maggots remained and were managed with petroleum jelly to suffocate them, while the urology team managed the genital infection without surgery. The patient’s clinical status improved rapidly, and he was transferred to a general medicine ward on the second day.

Blood cultures from a peripheral site grew Ignatzschineria indica, confirmed by mass spectrometry and gene sequencing, which was susceptible to multiple antibiotics including ceftazidime, ciprofloxacin, gentamicin, meropenem, piperacillin–tazobactam, and trimethoprim–sulfamethoxazole. Wound cultures revealed Morganella morganii, methicillin-susceptible Staphylococcus aureus, and Proteus mirabilis from the scrotal swab. Repeat blood cultures on day four were negative, and the central line was removed; no further surgical intervention was needed for the leg wound. The patient was diagnosed with previously unrecognized diabetes mellitus, with a hemoglobin A1c of 8.9%. Despite a systolic murmur and bacteremia, a transthoracic echocardiogram was normal. He completed 10 days of intravenous piperacillin–tazobactam followed by two weeks of oral amoxicillin–clavulanate due to the infection severity, underlying diabetes, and incomplete surgical source control.

Study Author Conclusions

We describe a case of Ignatzschineria spp bloodstream infection associated with wound myiasis. This report illustrates the potential utility of MALDI-TOF in the identification of Ignatzschineria spp, although this may depend on the instrument and database being used. Microbiologists and clinicians should be aware of uncommon bacteria, including Ignatzschineria spp, that may cause infection in patients with maggot-infested wounds such that these organisms are appropriately worked up and treated when found in clinical specimens.

The Brief Case: A Maggot Mystery—Ignatzschineria larvae Sepsis Secondary to an Infested Wound

Design

Case presentation

A 58-year-old man with hypertension, bipolar disorder, alcoholism, polysubstance abuse on methadone maintenance, treated hepatitis C, and chronic venous stasis with lower leg ulcers was brought to the Emergency Department after his brother’s fall. The apartment was insect-infested and covered with animal feces. The patient complained of a painful, draining left ankle wound present for 4 days, which was maggot-infested on exam.

He was afebrile with stable blood pressure initially (150/80 mm Hg) but later became hypotensive (85/56 mm Hg). Labs showed hyponatremia, hypoglycemia, leukocytosis, acute kidney injury, and elevated lactate. He received 1 liter of normal saline and empirical antibiotics: piperacillin-tazobactam and vancomycin.

A wound culture grew methicillin-resistant Staphylococcus aureus (MRSA). Blood cultures grew Gram-positive rods initially, prompting addition of metronidazole for anaerobic coverage. Further identification via MALDI-TOF and 16S rRNA sequencing revealed Ignatzschineria species, a Gram-negative rod resistant to tetracycline but susceptible to other tested antibiotics. After infectious diseases consultation, vancomycin, piperacillin-tazobactam, and metronidazole were discontinued and the patient was switched to oral levofloxacin.

The patient improved symptomatically and was discharged three days later to a subacute rehabilitation facility on oral levofloxacin and doxycycline. After completing a seven-day course, the nursing home medical team observed resolution of the cellulitis with a healed 5-cm eschar over the left medial malleolus. No further antimicrobial treatment was given, and the patient was advised to follow up in clinic if needed.

For research purposes, whole-genome sequencing (WGS) was performed on the isolate. DNA from the isolate was sequenced and compared to reference genomes of several Ignatzschineria species. Phylogenetic analysis showed that the patient’s isolate was most closely related to Ignatzschineria larvae, based on single-nucleotide polymorphism (SNP) distances, confirming species-level identification.

Study Author Conclusions

Ignatzschineria indica bacteremia in a patient with a maggot-infested heel ulcer: a case report and literature review

Design

Case presentation

An elderly diabetic patient with a history of myocardial infarction was brought to a community hospital by EMS after a fall at home, where squalid conditions including garbage and rats were noted. The patient was hypotensive (BP 89/70), tachycardic (HR 152), and had vomited once. Examination revealed a left foot wound covered with numerous maggots, cellulitis extending to the mid-lower leg, and excoriation of the toes and forefoot. Laboratory tests showed elevated white blood cell count (18.75 × 10^9/L), high blood lactate (11.2 mmol/L), acute kidney injury (creatinine 206 µmol/L), and poorly controlled blood glucose (random glucose 18.8 mmol/L).

The patient was resuscitated with 2 liters of normal saline and started on empirical piperacillin-tazobactam. The foot wound was irrigated with water and hydrogen peroxide to remove maggots.

Aerobic blood cultures grew Gram-variable bacilli initially reported as Gram-positive but later corrected to Gram-negative bacilli after MALDI-TOF MS identified the organism as Ignatzschineria indica (score 2.47). The isolate was confirmed by partial 16S rRNA and gyrB gene sequencing and showed susceptibility to tested antibiotics including ceftazidime, ciprofloxacin, meropenem, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole.

The patient was treated with piperacillin-tazobactam intravenously for 7 days, followed by oral amoxicillin-clavulanic acid for another 7 days. Daily manual maggot removal and povidone baths were performed on the foot wound. By hospital day 3, cellulitis was improving, and by day 4, no maggot infestation remained. The wound continued to heal with hydroalginate dressings every other day.

The patient was discharged on hospital day 14 with home wound care for dressing changes. They were readmitted a week later for unrelated reasons, stayed for a month, during which no additional antibiotics were needed. By the end of the second admission, the foot wound was fully healed.

Study Author Conclusions

To the best of our knowledge, this is the first case of I. indica bacteremia reported in Canada. All reported cases of bacteremia with I. indica have been associated with wound myiasis, and potential vectors for this organism are commonly found in North America. Some clinical isolates have shown resistance to broad-spectrum beta-lactams, with no formal resistance mechanism identified at this time. Poor socioeconomic status and living conditions were noted in all reported literature cases, which likely contribute to contacts with vectors carrying I. indica.

A Case of Ignatzschineria indica Bacteremia following Maggot Colonization

Design

Case presentation

A 46-year-old African American man with hypertension, stage 2 chronic kidney disease, and gout was brought to the emergency department after being found unresponsive and hypotensive. He was intubated in the field after pulselessness and received intravenous fluids and dopamine for hypotension. On arrival, he was hypotensive (BP 63/36 mm Hg), hypothermic (30.9°C), and had multiple maggot-infested laceration-type lesions along his back, a stage 4 sacral decubitus ulcer, and a left heel ulcer. The patient had been bedbound for 6–8 months due to gout pain and depression.

Laboratory findings included lactic acidosis, hyperkalemia, leukocytosis, anemia, and acute kidney injury. Urinalysis was positive for leukocyte esterase with numerous white blood cells. Blood and urine cultures were obtained. Empirical treatment with intravenous fluids, norepinephrine, intermittent vancomycin 1750 mg IV, and piperacillin-tazobactam 3.375 g IV every 6 hours was started. Hyperkalemia was medically managed, and a blood transfusion was given for anemia.

Blood cultures grew Streptococcus gallolyticus, Streptococcus anginosus, and an unidentified Gram-negative rod later identified as Ignatzschineria indica, susceptible to multiple antibiotics including amikacin, aztreonam, cefepime, ceftazidime, ciprofloxacin, gentamicin, levofloxacin, meropenem, piperacillin-tazobactam, and tobramycin. Urine cultures grew oxacillin-susceptible Staphylococcus aureus, and wound cultures grew Proteus mirabilis and diphtheroids.

On hospital day 7, piperacillin-tazobactam was switched to cefepime 2 g IV every 12 hours plus metronidazole 500 mg IV every 8 hours due to increased white blood cells and worsening renal function. Surgical debridement of back wounds cultured Escherichia coli and Proteus mirabilis, and pathology confirmed acute osteomyelitis of the sacrum.

Following surgery and antimicrobial therapy, the patient improved. Vancomycin was discontinued on day 8 after susceptibilities returned. Metronidazole was discontinued on day 10. After approximately 17 days of cefepime, treatment was changed to renally dosed oral levofloxacin 750 mg every 48 hours. Infectious Diseases recommended continuing levofloxacin for a total of six weeks from the start of cefepime to complete osteomyelitis treatment.

Study Author Conclusions

This case demonstrates the need for clinicians to be aware of possible Ignatzschineria infection in patients presenting with poor hygiene and presence of maggots. Medical staff should consider collecting samples of maggots from these infested wounds for further evaluation by professional entomologists in order to better understand the transmission of I. indica.