A 26-year-old male with HIV was referred from a local secondary level hospital with a presumptive diagnosis of infective endocarditis. Four days prior, he had presented complaining of a one-week history of fever, cough and dyspnoea. He reported a history of regular injection drug use, injecting a substance known locally as "nyaope" (a form of black tar heroin often combined with other active substances that may include crystal methamphetamine, cocaine, cannabis and antiretroviral medications such as efavirenz and ritonavir). He had been diagnosed with HIV two years previously and was taking a fixed-dose antiretroviral therapy (ART) combination of tenofovir, emtricitabine and efavirenz since that time, with poor self-reported adherence. Of note, he had no history of tuberculosis or any AIDS-defining opportunistic infections.
On examination, his temperature was 36.9  C, heart rate 110 beats per minute, blood pressure 85/73 mmHg, respiratory rate 36 breaths per minute, and oxygen saturation 80% on room air (99% on a rebreather mask at 15 L/min). He was pale, had digital clubbing and "track marks" on his forearms indicating recent injection drug use. His cardiac examination revealed a raised jugular venous pulsation and a soft first heart sound with a pan-systolic murmur over the tricuspid and mitral valves. He had scattered crackles over his lung fields bilaterally with a mild hepatomegaly. A chest radiograph showed an enlarged cardiothoracic-ratio, and his 12- lead electrocardiogram revealed a sinus tachycardia with evidence of left atrial enlargement. He was assessed as being in cardiac failure and was initiated on diuretics.
The white blood cell count was 15.35 x 109/L (reference range, 3.92 - 10.40); absolute lymphocyte count 1.11 x 109/L (reference range, 1.40 - 4.20); absolute neutrophil count 11.13 x 109/L (reference range, 1.60 - 6.98); haemoglobin 7.6 g/dL (reference range, 13.4 - 17.5); platelet count 61 x 109/L (reference range, 171 - 388); C-reactive protein was 27 mg/L (reference <10 ); procalcitonin 2.72 ug/L (reference range <0.1); creatinine 73 umol/L (reference range, 64 - 104); total bilirubin 34 umol/L (reference range, 5 - 21); conjugated bilirubin 24 umol/L (reference range, 0 - 3); alanine transaminase 226 U/L (reference range, 10 - 40); aspartate transaminase 226 U/L (reference range, 15 - 40), alkaline phosphatase 191 U/L (reference range, 53 - 128) and gamma-glutamyl transferase 68 U/L (reference, <68). A CD4 T cell count of 206 cells/uL and HIV viral load of 3640 copies/mL was on record having been done at the local ART clinic 2 weeks prior to presentation. Serology for hepatitis B was negative, however hepatitis C infection was confirmed by a quantitative polymerase chain reaction (PCR) with a viral load of 149000 IU/mL. Sputa sent for tuberculosis work up were negative for acid-fast bacilli on microscopy and negative on GeneXpert MTB/RIF PCR.
The first blood culture, taken on presentation, flagged positive after 21 h of incubation in the BacT/ALERT 3D (BioMerieux, Marcy l'Etoile, France) automated blood culture machine. The Gram stain showed Gram-negative bacilli and the positive culture was plated out onto 5% blood, CHOC and MacConkey agar and incubated at 35  C +- 2  C. Monomicrobial growth was noted on all three plates after approximately 18 h of incubation. The colony morphology on the MacConkey plate was of a non-lactose fermenter, with mid-sized, flat, translucent colonies with entire borders. The isolate was oxidase negative and identified using the API20E (BioMerieux, Marcy l'Etoile, France) system as Salmonella spp. (confidence level 99%). Confirmation serotyping with polyvalent O antigen was positive and the Salmonella Vi antigen was negative, and a laboratory identification of "Salmonella spp., non-typhoidal" was released. Antibiotic susceptibility testing was done using the Kirby-Bauer method. Antibiotic susceptibility showed a pan-susceptible isolate, and co-trimoxazole, ampicillin, ciprofloxacin (greater than 31 mm), ceftriaxone and chloramphenicol were released on the report. A repeat pair of blood cultures was received two days later, with one flagging positive for Salmonella spp. after 77 h of incubation and the other being negative for growth after 5 days. The two Salmonella isolates were referred to the national reference laboratory for serotyping. Both isolates were confirmed as Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) using whole genome sequencing.
Having been started empirically on ampicillin, cloxacillin and gentamicin on admission, antimicrobial therapy was adjusted to ampicillin and ciprofloxacin. Trans-thoracic and trans-oesophageal echocardiography revealed severe mitral and tricuspid valve regurgitation complicated by pulmonary hypertension (Fig. 1). Mitral valve perforations and vegetations were visible confirming the diagnosis of infective endocarditis (Fig. 1) and the indication for urgent valvular surgery. During the patient's workup for mitral valve replacement surgery (which was not available at our hospital) he developed acute limb ischaemia of his left forearm. An urgent computed tomography angiogram revealed occlusion of the left radial artery and an open arterotomy and thrombectomy was performed, restoring perfusion to his hand with a good clinical outcome and no consequent tissue or functional loss (Fig. 2). Thereafter, the patient was transferred to another hospital for mitral valve surgery. A mitral valve replacement was performed using a Hancock II bioprosthetic mitral valve (Fig. 3) and the patient was transferred back to our hospital one week post-operatively. During his admission he received physiotherapy, social worker support and ART adherence counselling. He received a total of 6 weeks of ampicillin and ciprofloxacin, and blood cultures were negative from 5 days after initiating targeted antimicrobials. Arrangement was made, on discharge, to continue with outpatient social support for substance addiction as well as follow up for management of his chronic hepatitis C and HIV infection.