Most cases of Yersinia enterocolitica manifest with symptoms of enterocolitis, such as diarrhoea, fever and abdominal pain. Y. enterocolitica is a very rare cause of pneumonia, and usually occurs in immunocompromised patients. We report a case of community-acquired pneumonia (CAP) caused by Y. enterocolitica in an elderly patient who did not develop symptoms of enterocolitis. This aetiology should be considered in patients with CAP who do not respond to initial empirical therapy.
Case reportThe patient was an 83-year-old female with a past medical history of paroxysmal atrial fibrillation and hypertension. She presented to the hospital with a 5 day history of shaking chills, fevers, a non-productive cough and haemoptysis. She denied any diarrhoea, abdominal pain, sick contacts, recent travel, recent hospitalization or antibiotic usage. She went to an outside hospital initially and was discharged home from their accident and emergency department with a presumed viral upper respiratory infection. She did not receive antibiotics and a chest X-ray was not performed. Her symptoms did not improve so she returned the next day to our accident and emergency department. Physical examination revealed a SpO 2 of 98 % on a BiPAP machine 10/5 cmH 2 O, pulse 87, respiratory rate 29, blood pressure 126/33 and temperature 38.7 u C. She was in moderate respiratory distress with accessory muscle use. A chest X-ray showed a right lower lobe infiltrate consistent with pneumonia. Two sets of blood culture were obtained. Due to multiple antibiotic allergies (penicillin caused hives, trimethoprim-sulfamethoxazole caused a rash and hives, moxifloxacin caused an unknown reaction), she was started on azithromycin and clindamycin empirically and admitted to the hospital. Her initial CURB-65 score was 3, with a calculated mortality rate of 17 %.On hospital day 1, two blood cultures grew Gram-negative bacilli. Intravenous aztreonam was initiated. Both urinary streptococcal and legionella antigen tests were negative. On hospital day 2, the patient's respiratory condition worsened and she was transferred to the intensive care unit. She was noted to have a temperature of 38.7 u C. Azithromycin and clindamycin were discontinued after blood cultures revealed Y. enterocolitica sensitive to amikacin, aztreonam, cefepime, ceftazidime, ceftriaxone, ciprofloxacin, doripenem, gentamicin, levofloxacin, meropenem, piperacillin-tazobactam, tobramycin and trimethoprim-sulfamethoxazole. An echocardiogram was completed which showed moderate mitral regurgitation without any vegetations. A computed tomography scan of the abdomen and pelvis with oral and intravenous contrast showed no acute colonic changes. Her condition improved and she was transferred back to the regular hospital ward on day 3. She was sent to an extended care facility on hospital day 8 for rehabilitation and to complete a 14 day course of intravenous aztreonam.
DiscussionY. enterocolitica is a pleomorphic Gram-negative bacillus that belongs to the family Enterobacteriaceae. It is a lactose n...