pasteurella multocida was first described by revolee in 1877 and further characterized by pasteur in 1880 . pasteurella species usually have low virulence in humans , but serious manifestations sometimes occur and can lead to bacteremia . we present a patient who developed septic shock as a result of p. multocida bacteremia , presumptively from an intra - abdominal infection . a 52-year - old african american female was brought to the emergency department for generalized abdominal discomfort , altered mental status , diarrhea , fevers and chills for 4 - 5 days . her past medical history was significant for alcohol abuse and alcohol - related liver cirrhosis . in the emergency department , vital signs were as follows : blood pressure of 74/42 mmhg , heart rate of 112 beats / min , respiratory rate of 20 breaths / min and temperature of 98.6 f. remarkable findings on physical examination included jaundice as well as abdominal distention and tenderness to palpation , especially in the right upper quadrant . as per family , she did not have recent travels or exposure to sick people . they denied having domestic animals at home or any contact to the patient with pets . admission diagnosis was systemic inflammatory response syndrome with sepsis and septic shock with multi - organic dysfunction syndrome , presumptively secondary to community - acquired pneumonia , possible biliary tract infection ( ascending cholangitis ) , probable spontaneous bacterial peritonitis ( sbp ) and alcoholic hepatitis . empiric intravenous antimicrobial therapy , composed by piperacillin / tazobactam ( 2.25 g every 8 h ) and azithromycin ( 500 mg every 24 h ) , was initiated . laboratory results on admission were : a complete blood cell count of 21,000/mm(90% neutrophils ) , a platelet count of 51,000/mm , a sodium level of 127 meq / l , a potassium level of 5.3 meq / l , a bicarbonate level of 15 meq / l and a creatinine level of 6.3 mg / dl . alkaline phosphatase level was 290 iu / l , gamma - glutamyl transpeptidase level was 290 u / l and lactate dehydrogenase level was 482 total bilirubin level was 14.5 mg / dl , with a direct bilirubin level of 10.1 mg / dl . arterial blood gases showed a ph of 7.15 , a pco2 of 23 , and a po2 of 132 while the patient was receiving mechanical ventilation with fio2 of 60% . after 24 h of admission , patient remained in critical condition and requiring maximum doses of vasopressors , despite of what it seems to be the appropriate empiric antimicrobial therapy . blood culture system bact - alert 3d was used for the recovery of the organism . no minimal inhibitory concentrations for these antimicrobials were reported . in spite of all medical efforts , p. multocida is a small gram - negative non - spore forming facultative anaerobe organism that is a natural inhabitant of the normal gastrointestinal flora and the upper respiratory tract of wild and domestic animals , especially cats and dogs . it is easily overgrowing by other flora in the sputum and might be regularly missed , as it resembles haemophilus influenzae , francisella tularensis and yersinia pestis . the five species that cause the majority of pasteurellosis are : multocida , septica , canis , stomatis , and dagmatis . human p. multocida infections have been reported to occur with and without animal exposure , the former mostly associated with the domestic cat and dog bites or scratches . most of the infections involve the skin and soft - tissues and they can be complicated by abscess formation , osteomyelitis or septic arthritis . the respiratory tract is the second most common site of infection with a wide spectrum of diseases that includes rhinosinusitis , tracheobronchitis , epiglottitis , pneumonia , empyema and lung abscesses . the majority of p. multocida pneumonia cases occur in elderly patients with underlying chronic pulmonary disease . invasive forms of p. multocida infection usually occur in immunocompromised patients , such as those with advanced age , chronic renal failure , solid tumors , hematological malignancies , diabetes mellitus or liver cirrhosis . p. multocida causes a wide variety of disease , including abdominal and pelvic infections , endocarditis , meningitis and endophtalmitis . von graevenitz et al . reviewed 21 proven cases of p. multocida bacteremia . a remarkable number of those cases involved patients with liver diseases , including liver cirrhosis of any etiology , hepatitis and infiltrating tumors . impaired function of the reticuloendothelial system and the presence of portosystemic shunts in patients with liver disease seem to play a major role in the development of bacteremia . this case seems peculiar in that no direct contact with a domestic animal could be documented . our patient had a history of alcohol - induced liver cirrhosis , which predisposed her to the development of bacteremia . however , retrospectively , it is difficult to establish the primary source of infection in this case . the findings of the abdominal examination may suggest that the primary source was the intra - abdominal cavity . unfortunately , the medical team was not able to performed paracentesis to obtain ascitic fluid for cytology and cultures due to patient s medical condition . no abdominal imaging was available . on the other hand , the chest radiography findings of infiltrate and pleural effusion may point the respiratory tract as the primary source of infection . we believed that , given the history of symptoms on admission and the presence of underlying liver disease , the intra - abdominal cavity was the most likely primary source of infection in this patient . nasopharyngeal colonization with p. multocida with transient bacteremia and seeding of the peritoneal cavity in immunosupressed cat owners could play an important role in the development of sbp . ten of these patients were exposed to animals , nine had positive blood cultures and four patients died . however , penicillin - resistant strains in human infections have been described . in these cases , 2 and 3 generation cephalosporins , macrolides , fluoroquinolones , tetracyclines , and trimethoprim - sulfamethoxazole outcome is associated with severity of the infection , the extent of the underlying disease and the early initiation of appropriate therapy . although cases of bacteremic p. multocida infections has been infrequently reported in the literature , clinicians should considered this organism as an important and potentially lethal pathogen in humans , where it can cause life - threatening infections . p. multocida should be included in the microbiologic differential diagnosis in patients with underlying chronic liver diseases who presents with possible intra - abdominal infection , even without history of exposure to domestic animals .
pasteurella multocida is a gram - negative organism characterized morphologically as coccobacillus . 
 it is the commonest organism infecting pet bites . 
 however , severe infections may occur in the absence of animal bites or scratches . 
 pasteurella multocida serves as an opportunistic pathogen in humans , especially in patients with depressed immune system . 
 few cases in the literature identify pasteurella multocida as the causative agent of septic shock , especially in cirrhotic patients . 
 we report a patient who presented with septic shock as a result of pasteurella multocida bacteremia , without prior history of animal exposure .