A 30-year-old presented to the emergency department with an 8-day history of widespread pustular follicular lesions, particularly concentrated in the axillary and anterior torso regions. The patient had just returned from a 2-week trip with his wife to the Azores, Portugal, 1 day before the rash appeared. The day before the patient's return he had visited a hot spring on Sao Miguel Island.
Six days prior to hospital admission, most of the patient's lesions had subsided and resolved except for three sites: one in his right axilla and two lesions in the right lower abdominal area. Over the subsequent days, these began to increase in size, most notably the right axillary lesion. One day preceding hospital admission the patient became systemically unwell with fevers, vomiting and anorexia. His only significant past medical history was discoid lupus managed with topical steroids. He worked as a health economist, was a non-smoker and had no history of recreational drug use.
On examination at admission, he was pyrexial (37.7  C) and tachycardic (heart rate 135 min-1) with a blood pressure of 112/66 mmHg. His respiratory rate was 25 breaths min-1 and his oxygen saturation was 98 % on room air. He was noted to have a fluctuant, tender and warm mass in his right axilla measuring 8x3 cm, as well as less-defined fluctuant mass in his suprapubic region with overlying erythematous skin.
His admission complete blood count showed results of haemoglobin 125 g l-1 and total WBC 35.31 109 l-1, with an absolute neutrophil count of 30.47 109 l-1. His lactate was 2.04 mmol l-1, his eGFR was 69 ml min-1 and his C-reactive protein was 338 mg l-1. His admission blood culture did not have any growth after 48 h and 5 days' incubation. An HIV screening test was negative. A methicillin-resistant   Staphylococcus aureus   skin swab screen was negative.
He was admitted under the general surgeons with a diagnosis of systemic sepsis secondary to bacterial abscesses. He was started empirically on intravenous amoxicillin/clavulanic acid. A surgical incision and drainage was performed on his abdominal and axillary lesions on the day of admission, with large quantities of pus being drained, which was sent for microscopy and culture. A macroscopic image of the incised abdominal lesion is presented in Fig. 1.
The pus fluid obtained from both surgical sites was set up and incubated on blood agar (BA), chocolate blood agar (CBA) and a cysteine-lactose-electrolyte-deficient agar (CLED). No organisms were seen on auramine staining, and the samples were analysed on the GeneXpert platform and found to be negative for   Mycobacterium tuberculosis  . After 24 h incubation, smooth, round and convex colonies were noted on the CBA plate. A subset of colonies was processed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) (Bruker, USA), which reported a result of   C. violaceum   with a modified score value of 1.86, indicative of identification to genus level.
Post-operatively he was transferred back to a ward environment. Day 1 (D1) post-admission he developed persistent fevers (>38  C) and became increasingly hypotensive, tachycardic and oliguric despite adequate fluid resuscitation. A CT scan taken at the time confirmed the presence of multiple soft tissue nodes and pulmonary nodules, as well as complications related to systemic sepsis, such as bilateral patchy basal consolidation. His antimicrobials were switched to piperacillin/tazobactam and intravenous clindamycin. He was taken for a surgical washout of his lesions and then transferred to the intensive therapy unit (ITU) for haemodynamic support with ionotropes.
D2 post-admission he was reviewed by the Infectious Diseases team on the ITU, with the results of the initial laboratory analysis suggestive of   C. violaceum  . Based on the organism identification, the empirical antimicrobial treatment regimen was changed to meropenem, intravenous ciprofloxacin and gentamicin.
Further microbiological tests and results were available at this point. A legionella urinary antigen test was negative. A peripheral blood culture taken on D1 post-admission had flagged positive on the incubator with an organism identified via MALDI-TOF as a   Chromobacterium   spp. Growth plates of the initial pus sample are shown in Fig. 2. Antimicrobial susceptibility testing on the initial pus samples using a disc diffusion method was employed (Fig. 3). Discs on Mueller-Hinton agar were set up for ceftazidime, gentamicin, meropenem, ciprofloxacin, piperacillin/tazobactam and amikacin using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints for   Pseudomonas   spp.
The patient improved following the switch of his antimicrobials. He was stepped down to the general surgical ward on D5 post-admission. Antimicrobial disc sensitivities reported good zone diameter sizes for meropenem (33 mm) and ciprofloxacin (35 mm), and so all of his antimicrobials were discontinued except for meropenem. A transthoracic echocardiogram did not show any evidence of valvulopathy. His clinical state, mobility and appetite improved over the next week and he was discharged on D12 with a course of oral ciprofloxacin 750 mg twice daily to complete a total of 6 weeks of effective antimicrobial use.
Subsequent final microbiological tests were completed in the interim. Extended fungal cultures after 3 weeks did not yield any growth, and TB cultures on tissue and pus samples from the abscesses were negative. The final report returned from the national reference laboratory (BRD, PHE Colindale) indicated a species ID of   C. violaceum   and the following MICs: ciprofloxacin (4 mg l-1), ceftazidime (4 mg l-1), imipenem (2 mg l-1), meropenem (2 mg l-1) and piperacillin/tazobactam (4 mg l-1).