First Report of Wohlfahrtiimonaschitiniclastica Isolation from a Patient with Cellulitis in the United States

Abstract

We report the first documented isolation of Wohlfahrtiimonas chitiniclastica from a human in the United States. Initially misidentified as Acinetobacter lwoffii by Vitek-2, the isolate was subsequently identified as W. chitiniclastica by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing. While the clinical significance of the isolate in this case is unclear, it highlights the superior performance of MALDI-TOF MS for bacterial identification. CASE REPORTA 26-year-old morbidly obese male courier worker was admitted with worsening right leg swelling and draining ulcers. He had developed lymphedema of the right leg during the preceding year after undergoing surgical correction of a right lower extremity varus deformity. A few weeks prior to the current admission, he had noticed right leg ulcers draining yellowish green serosanguineous fluid. On admission, he was afebrile and his white blood cell count was 11,100/l. He was found to have right lower extremity cellulitis.A swab was collected from the right leg and sent to the microbiology laboratory for wound cultures. The sample was inoculated onto blood, chocolate, and MacConkey agars and incubated under aerobic conditions at 37°C. Gram staining revealed many Gram-negative bacilli and moderate Gram-positive cocci. Four different organisms were isolated from the swab after growth. Microbial identification of each isolate was performed by using routine biochemical tests, including automated identification by the Vitek 2 system (bioMérieux, Marcy l'Etoile, France). The organisms were identified as Proteus vulgaris, Klebsiella pneumoniae, Acinetobacter lwoffii, and Staphylococcus aureus. The isolates were subsequently analyzed in triplicate by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) (RUO version 3.1, Bruker Biotyper; Bruker Daltonics, Bremen, Germany). Of note, the isolate identified as A. lwoffii by the Vitek 2 system was identified by MALDI-TOF MS as Wohlfahrtiimonas chitiniclastica, with identification log (score) values of 2.253, 2.296, and 2.229. Log (score)

Wohlfahrtiimonas chitiniclastica: current insights into an emerging human pathogen

“…Antimicrobial susceptibility testing was performed in 11 out of the 12 cases and revealed that W. chitiniclastica is susceptible to β-lactam antibiotics, quinolones, aminoglycosides, colistin, trimethoprim/ sulfamethoxazole and tetracyclin as reported in the literature [4,6,7,[13][14][15] and measured in our isolates given in Table 3. According to our investigations the MIC value determined for fosfomycin is very high ( Table 3).…”

“…chitiniclastica patients, their underlying diseases and cause of hospitalization are listed in Table 1. Most patients suffered from diseases affecting the skin such as ulcers (cases 9-11 [13][14][15]), wounds (cases 7 and 8 [15]), gangrene (cases 4 and 5 [7,13]) or cellulitis (case 5 [13]). Patients suffered also from impairments of the cardiovascular system such as occlusive arteriopathy (case 2 [6]), hypertension (cases 3 [12] and 11), different heart diseases (cases 3 [12], 9 and 11), chronic venous insufficiency (cases 9 and 11) or deep vein thrombosis (case 12).…”

“…Furthermore, another publication about the pathogen's occurrence in the insect species Hermetia illucens [3] and a report on a whole genome sequence of a W. chitiniclastica strain [11] appeared. To date, seven case reports and in total eight cases have been published on W. chitiniclastica infections in humans (case numbers: 1 [4], 2 [6], 3 [12], 4 [7], 5 [13], 6 [14], 7, 8 [15]). Additionally, we report on the outcome of four patients treated at Dresden University Hospital during the last three years (cases 9-12).…”

Wohlfahrtiimonas chitiniclasticaInfections in 2 Elderly Patients, Hawaii, USA

“…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 ).…”

Fly Reservoir Associated with Wohlfahrtiimonas Bacteremia in a Human

“…The scarcity of reports of Wohlfahrtiimonas spp. infections might be attributable to the difficulty in laboratory identification ( 7 , 8 ) or because wound myiasis is routinely addressed with broad-spectrum antimicrobial drugs.…”