A 58-year-old male patient was admitted to our department due to cough, wheezing, and fever for 20 days. The patient was confirmed to be HIV positive two month ago, the baseline CD4 + T-cell count and HIV-RNA level were unknown, antiviral therapy (ART) has been given with BIC/FTC/TAF. His past medical history included type 2 diabetes, alcohol abuse, and a 30-year pack history of tobacco smoking. In addition, the patient’s oral hygiene was not good, who had a history of gum swelling and pain, and one teeth had been extracted three month ago.

20 days before admission, the patient begun to paroxysmal cough and expectoration. Accompanying with shortness of breath mainly after exercise, and fever mainly in the afternoon and night, with a maximum body temperature of 39℃. Moreover, he had no chest tightness, chest pain, hemoptysis, palpitations, or other discomforts. So he was admitted to a local hospital, and chest computed tomography (CT) revealed infectious lesions in both lungs and a amount of right-sided pleural effusion. Closed thoracic drainage was performed to drain approximately 2000 ml of milky white pleural fluid, and received antibiotic therapy (specific drugs were unknown), however, symptomatic improvement was not noted. The patient was subsequently transferred to our hospital for further treatment.

On admission, his temperature was 37.0 ℃, pulse rate 116 beats/min, respiratory rate 30 breaths/min, blood pressure 148/82–mmHg, and oxygen saturation 94% on room air. Oral examination showed calculus and a tooth defect. No lymphadenopathy was detected. Pulmonary auscultation found decreased breath sounds on right lower fields. No abnormalities were detected upon cardiac and abdominal physical examination, Moderate edema of both lower limbs. The results of his laboratory examination were as follows: arterial blood gas revealed PH 7.34 (normal range: 7.35–7.45), oxygen pressure (PaO2) 58–mmHg (normal range: 83–108–mmHg) and oxygenation index 276–mmHg (normal range: 400–500 mmHg), white blood cell (WBC) count 14.84 × 10^9/L (normal range, 3.5–9.5 × 10^9/L), neutrophil ratio 89.90% (normal range, 40–75%). procalcitonin (PCT) 2.347 ng/ml (normal range, 0–0.05 ng/ml), C-reactive protein (CRP) 309.55 mg/L (normal range, 0-4 mg/L) with a erythrocyte sedimentation rate (ESR) of 66 mm/h (normal range, 0–20 mm/h), serum albumin 27.9 g/L (normal range, 40-55 g/L) and his fasting blood glucose was 12.98mmol/L (normal range, 3.9–6.1 mmol/L). CD4 + T-cell count 61 cells/µl, CD4/CD8: 0.46; HIV viral loads: 1.02E + 02 (copes/ml). Chest enhancement CT revealed multiple encapsulated pleural effusions, pneumatosis, and pleural thickening on the right side, partial compressive atelectasis in the right lung; a small number of scattered infection foci in the right lung; multiple small bullae in both lungs (Fig. 1). Subsequently, thoracocentesis was performed and a chest tube was introduced. Milky white pleural fluid was aspirated, laboratory analysis showed WBC count 230,600/mL, polymorphonuclear neutrophil count 93%, lactate dehydrogenase 7230IU/L (normal range, 109-245U/L), glucose 1.4 mg/dL (normal range, 2.4-4.5 mg/dL), protein level 8.0 g/L (normal range, 0–30 g/L), and adenosine deaminase 352.5 IU/L (normal range, 0–24 IU/L). Pleural fluid smear, gram stain, acid-fast bacilli culture and smear, and cytology were all negative. Electrocardiogram (ECG), abdominal ultrasound and fiberbronchoscopy were no abnormal changes. Culture specimens (including blood, sputum, pleural water and bronchoalveolar lavage fluid (BALF)) are retained before antibiotic.

The primary diagnosis were 1. empyema, 2. sepsis (according to SOFA score) [11], 3. AIDS, 4. type 2 diabetes, 5. hypoalbuminemia. It is vital to administer empirical antibiotics before bacterial culture results, especially in patients with severe infections. For empyema, the British Thoracic Society (BTS) and American Association for Thoracic Surgery suggest broad-spectrum antibiotics with Gram-positive, Gram-negative and anaerobic cover until culture and sensitivities are available [12, 13], so intravenous empiric meropenem (1 g once every 8 h) was commenced. He also continued to receive BIC/FTC/TAF for anti-human immunodeficiency virus (anti-HIV) treatment and metformin combined with glimepiride for controlling blood sugar. Meanwhile, the pleural effusion was drained continuously through the chest tube, and received repeated washout with urokinase (100000U/d) to avoid insufficient drainage.

Culture tests of the pleural effusion identified the presence of S constellatus on the fourth day of hospitalization, which was sensitive to penicillin, levofloxacin, ceftriaxone, linezolid and vancomycin, but resistant to tetracycline and clindamycin (Table 1), whereas S. constellatus was not detected in culture tests of the patient’s blood, sputum and BALF. After 3 days of treatment, body temperature returns to normal (fever on day 1 and day 2) and laboratory test results (WBC count 6.84 × 10^9/L, neutrophil ratio 78.90%, PCT 0.556 ng/ml, CRP 114.99 mg/L, PCT 0.556 ng/ml) showed improvement, antibiotic therapy was changed to intravenous amoxicillin clavulanate potassium (1.2 g once every 8 h) and metronidazole (0.2 g once every 8 h) according to the antibiotic susceptibility test results. On the 12th day of admission, the close thoracic drainage tube was removed, and the patient claimed gradually resolved symptoms under antibiotic treatment and effusion drainage, and then he was discharged for economic reasons. He continue to take a two-weeks oral amoxicillin clavulanate potassium tablet (1.2 g once every 8 h) after discharge. One month after treatment, repeat chest CT showed resolution of empyema (Fig. 1).

Chest CT. (A) before treatment, revealed multiple encapsulated pleural effusions, pneumatosis, and pleural thickening on the right side, partial compressive atelectasis in the right lung; a small number of scattered infection foci in the right lung; multiple small bullae in both lungs. (B) Twelve days after treatment. (C) Four weeks after treatment, (B) and (C) indicate that pleural effusion were improved