A case of fulminant community-acquired Acinetobacter baumannii pneumonia in Korea
A 53-year-old male patient visited the emergency room for worsening symptoms of productive cough, fever, and chills that developed the day before. The patient, with no specific occupation, had a 30-pack/year history of cigarette smoking and consumed alcohol in moderation. He was successfully treated for CAP in another hospital 2 years prior and had experienced no other problems. Upon admission, the patient appeared acutely ill. His blood pressure was 82/46 mmHg, respiratory rate was 22 breaths per minute, pulse rate was 120 beats per minute, and body temperature was 40℃. A regular heart rhythm was observed and there were coarse breathing sounds with crackles on the right lower lung field.\nThe laboratory chemistry values were as follows: white blood cell count of 11,500/mm3 with 86.1% neutrophils, 11.5% lymphocytes, 1.9% monocytes, 0.2% eosinophils; hemoglobin 14.4 g/dL; platelet count 188,000/mm3; C-reactive protein 1.28 mg/dL. The arterial blood gas analysis at room air was pH of 7.47, pCO2 of 22.4 mmHg, pO2 of 52.5 mmHg, HCO3- of 16 mmol/L, and O2 saturation of 89%. Blood chemistries showed a blood urea nitrogen (BUN)/creatinine (Cr) level of 9/2.05 mg/dL and the serum sodium, potassium, and chloride were 139, 4.1, and 105 mmol/L, respectively. The urine sodium was 19 mmol/L, urine Cr was 222.31 mg/dL, and the calculated fractional excretion of sodium was 0.1%. A simple chest radiograph showed moderate patchy consolidation in the right lower lobe (). We made a presumptive diagnosis of sepsis caused by CAP.\nSeptic shock was suspected due to low blood pressure. A central line catheter was promptly inserted, along with fluid resuscitation, and oxygen was administered via nasal cannula. Cultures of blood, sputum, and urine samples were also completed. Empiric piperacillin/tazobactam with ciprofloxacin injections were administered simultaneously. The patient was admitted into the intensive care unit for directed therapy of septic shock. The initial APACHE II score was 25. Low blood pressure persisted after vigorous fluid therapy; thus, the vasoactive agent norepinephrine was administered. Vasopressin was later added when the mean arterial pressure did not normalize. Sixteen hours after admission, respiratory distress worsened, resulting in acute respiratory failure with arterial blood gas analysis showing a pH of 7.085, pCO2 of 61.4 mmHg, and HCO3- of 19 mmol/L. The patient was immediately intubated with mechanical ventilation at FiO2 of 1.0 and positive end expiratory pressure at 14 cmH2O; however, hypoxia persisted and respiratory and metabolic acidosis continued to deteriorate. Twenty-four hours after admission, follow-up arterial blood gas analysis showed a pH of 7.096, pCO2 of 63.7 mmHg, pO2 of 77.6 mmHg, HCO3- of 20 mmol/L, and O2 saturation of 89%. The follow-up chest radiograph showed more exacerbated consolidation in the right lung field with the beginning of patchy opacities in the left lower lobe (). The antibiotics were then switched to meropenem with teicoplanin. Twenty-eight hours after admission, oliguria ensued along with deteriorating acute kidney injury with BUN/Cr at 26/3.66 mg/dL. Continuous renal replacement therapy was promptly initiated. After 36 hours of intensive treatment, septic shock and acute respiratory failure did not improve and the patient went into cardiac arrest. Cardiopulmonary resuscitation was performed for 30 minutes but the patient did not recover.\nAfter the patient expired, AB was identified in both the culture of sputum and two pairs of blood samples taken during the emergency room visit. Bacterial sensitivity to antibiotics was measured using isolates from both sputum and blood cultures. The bacterial isolate was susceptible to piperacillin/tazobactam, ceftazidime, cefepime, imipenem, meropenem, gentamicin, and tobramycin; tolerant to ampicillin, amoxacillin/clavulanic acid, cafalotin, cefoxitin, and trimethoprim/sulfamethoxazole; and moderately tolerant to cefotaxime and levofloxacin (). A VITEK device (VITEK 2, Biomerieux, Marcy I'Etolile, France) was used for culturing, and the sensitivity test was conducted in accordance to the Clinical and Laboratory Standards Institute.