he was admitted for an elective left typanomastoidectomy and removal of the incus and malleus with tympanoplasty .
his medical history included hypertension , dyslipidemia , gout , polycystic kidney disease and gastroesophageal reflux disease .
his medications at the time of admission were rosuvastatin , domperidone , esomeprazole , allopurinol , irbesartan / hydrochlorothiazide and labetalol . on the first day
postoperatively the patient experienced a sudden drop in his level of consciousness accompanied by marked agitation , and required intubation .
his glasgow coma scale score was 9 ( eyes 3 , verbal 3 , motor 3 ) .
there were no focal neurological signs , his pupils were symmetrical but sluggish to react and the fundi appeared normal .
a computed tomography scan of the patient s head showed no structural abnormalities , no masses and no hematoma .
lumbar puncture was performed and revealed cloudy cerebrospinal fluid ( csf ) with an elevated protein level ( 5.78
g / l ) , low glucose level ( < 1.0 mmol / l ) and a leukocyte count of 11,97410/l , with 95% neutrophils . based on these findings , the patient was treated empirically for bacterial meningitis with intravenous ( iv ) vancomycin , ceftriaxone and dexamethasone pending culture results and sensitivities .
further blood work revealed a blood leukocyte count of 13.810/l , hemoglobin level of 123 g / l and platelet count of 15410/l .
mmol / l , potassium level 3.6 mmol / l , chloride level 106 mmol / l , urea level 12.6 mmol / l and creatinine level 190 mol / l . initial gram stain of the csf using the cytospin technique revealed abundant polymorphonuclear leukocytes and no organisms .
preliminary reports revealed growth of gram - negative coccobacilli , and at this point metronidazole was also added to the treatment regime until an anaerobic cause was ruled out .
ultimately , the organism was identified from aerobic cultures as p multocida using the vitek 2 identification system ( biomrieux , usa ) .
interestingly , a swab of the left ear performed on postoperative day 2 grew the same organism as that cultured from the csf ( growth on chocolate and blood agar ; no growth on macconkey s or inhibitory mold agar ) .
the empirical antibiotics and dexamethasone were discontinued , and the patient was started on a 14-day course of iv penicillin g at a dose of 2,000,000 units every 4 h. the patient made a rapid recovery from his meningitis , and he was discharged on postoperative day 10 to continue treatment as an outpatient . on further questioning , it was revealed that the patient was the primary caregiver of several pet cats and a dog , although he reported no history of bites .
the pets were allowed on the furniture , including his bed , and would occasionally lick his face .
meningitis is an uncommon outcome of p multocida infection ( 3 ) , making p multocida a rare cause of adult bacterial meningitis .
two reviews spanning 1950 to 1999 report only 29 cases published in the english literature during that time period ( 4,5 ) .
animal contact was a major risk factor , present in 89% of cases , and a history of a bite was much less common , occurring only 15% of the time ( 4 ) .
previous cranial / facial surgery or skull fracture has been reported as a cause of p multocida meningitis ( 513 ) .
table 1 summarizes adult cases of p multocida meningitis published in the english literature after 1999 ( 1322 ) .
animal contact was present in all cases , while only two ( 20% ) reported a history of a bite .
the current report presents one of only a handful of cases of p multocida meningitis ever documented in the literature from a canadian site ( 5,6,9,21,23 ) .
the patient had the typical csf findings of bacterial meningitis ( low glucose , high protein , high leukocytes ) .
penicillin is the most commonly used antibiotic to treat p multocida meningitis ( 4,15 ) , and our patient recovered fully with a course of iv penicillin g. many of the more recent cases describe treating with third generation cephalosporins ( table 1 ) .
p multocida meningitis has been reported following mastoidectomy ( 11,12 ) , and the pathogenesis of infection is hypothesized to involve contiguous spread of the organism from a colonized ear canal . supporting this theory ,
local spread from an adjacent infected site has been proposed as an etiology ( 4 ) because chronic otitis media and otorrhea have been found in association with p multocida meningitis ( 4,19,2427 ) .
our patient showed no signs of clinical meningitis preoperatively ; therefore , extension to the surgical site is the likely mechanism in this case .
a preoperative ear swab has been proposed for patients having a mastoidectomy that have a history of exposure to animals ( 12 ) , and may be supported by the present case .
 pasteurella multocida is a gram - negative anaerobe that is known to colonize household pets ; in fact , it has been reported to be present in a majority of cats and dogs . 
 p multocida can cause a variety of infections in humans , of which skin infections are the most common . 
 this article describes a case involving a 56-year - old man who developed meningitis caused by p multocida following tympanomastoidectomy . 
 the authors discuss the treatment course and most likely route of infection in this case , and summarize the cases of p multocida - associated meningitis presented in the literature . 
CASE PRESENTATION
DISCUSSION