it contaminates water and hospital devices and is known as aetiological agent of nosocomial infection . community - acquired infection of this organism had been reported ( hadi et al . , 2007 ) . the prevalence of p. aeruginosa bacteremia varies from one to other institutions and the sources of bacteremia were identified in 66 % of cases ( vitkauskiene et al . , altogether 21% of these bacterial infections were classified as community - acquired infection ( parkins et al . , 2010 ) . a 58-year - old malay male with background medical problem of hypertension and dyslipidemia presented with fever and right leg swelling for three days duration prior to admission . the fever was described as a high grade and it was associated with chills and rigors . the right leg swelling was sudden onset and it was associated with severe throbbing pain . there was no prior history of trauma and insect bite . there was neither chest pain nor shortness of breath . because of that he had some difficulty while walking . on clinical examination his blood pressure was normal but he was tachycardic with heart rate of 130 beats per minute . ultrasound doppler of the right leg showed no evidence of deep vein thrombosis and no osteomyelitis changes of the right tibia and fibula were noted by x - ray . his total white cell count was within normal limit but the neutrophil level was elevated . blood sample from the patient was sent for culture on the day of admission , grew gram - negative rods after one day of incubation . the organism produced hemolytic colonies on blood agar and greenish diffusible pigment seen on the muller hinton agar ( mha ) with typical odor of pseudomonas aeruginosa . it was non - lactose fermenter with alkaline reactions at both butt and slant in the triple sugar iron agar . the patient was not responding to the empirical antibiotics and they were judiciously replaced by intravenous cefepime 1 gram 12 hourly . the c - reactive protein and white cell counts also were decreasing in trend as shown in table 1(tab pseudomonas aeruginosa is a leading cause of nosocomial infection and associated with high mortality rate ( fazlul et al . , 2011 ) . pneumonia and sepsis are the most common infections associated with these bacteria ( tam et al . , 2009 ) . this is a case of pseudomonas aeruginosa bacteremia , which we believe might have acquired from community setting . cases of community - acquired p. aeruginosa bacteremia represent about 21 % of all cases of p. aeruginosa bacteremia ( parkins et al . , 2010 ) . community - acquired p. aeruginosa infections occurred in those with specific predisposing factors such as neutropenic and chronic structural lung diseases such as cystic fibrosis and bronchitis ( schechner et al . , 2009 ) . in our case , we could not find any significant risk factors that are associated with community - acquired p. aeruginosa infection . from hospital - based study , p. aeruginosa accounted around 2.7 % of all bacteremia cases and the primary source is identified in 60 to 70 % of the cases , with respiratory tract as most common site of infection ( vitkauskiene et al . , 2010 ) . most of the time , community - acquired p. aeruginosa infection presents as otitis externa ( hadi et al . , 2007 ) . staphylococcus aureus and beta hemolytic streptococci are the most common aetiological agents for cellulitis and p. aeruginosa is not a common cause of cellulitis ( dryden et al . , 2009 ) . p. aeruginosa was not suspected in our case at the time of presentation due to this knowledge . skin and soft tissue infections caused by this organism can appear as primary or metastatic foci , expressed in wide presentations including cellulitis , ecthyma gangrenosum , necrotizing fascitis and gangrene ( giamerellou , 2000 ) . independent predictors of p. aeruginosa bacteremia in community setting were severe immunodeficiency , age > 90 years , receipt of antimicrobial therapy within past 30 days , and presence of central venous catheter or urinary device ( schechner et al . , 2009 ) . perhaps , molecular methods are the most appropriate investigational tool to identify clusters of pseudomonas aeruginosa that belong to community or hospital - acquired skin and soft tissue infection in origin ( hadi et al . , 2007 ) . treatment of p. aeruginosa is always challenging because these bacteria can easily develop resistance to many classes of antibiotics . p. aeruginosa is known to possess many resistance genes thus it is associated with multiple mechanisms of antibiotic resistance ( tam et al . , 2007 ) . over - expression of ampc is one of the resistance mechanisms that commonly exist in p. aeruginosa . we were able to see the similar phenotype of ampc overexpression in our isolate in this case . the patient responded well to the treatment and completed the antibiotic course for 14 days . ampc overexpression was found to be associated with non - susceptibility to ciprofloxacin by cabot et al . , 2011 . however this association did not occur in this case as the organism is still susceptible to ciprofloxacin . the 30-day mortality rate shown by a study in japan was 20.9 % with thrombocytopenia and polymicrobial infections as the significantly contributing factors ( horino et al . , 2012 ) . perhaps , absence of these two factors could contribute to better outcome in our case . pseudomonas aeruginosa is not a common aetiological agent of community - acquired skin and soft tissue infection with bacteremia . its infections in community should be managed cautiously particularly in high - risk populations those are immunosuppressant . treatment of pseudomonas aeruginosa infection is always challenging as the organism easily acquires resistance to different classes of antibiotics . authors thank the dean of the faculty of medicine and the head of the department of medical microbiology and immunology , the national university of malaysia for cooperation and help .
pseudomonas aeruginosa is a gram - negative bacillus that causes wide spectrum clinical infections . 
 however , it is most frequently associated with hospital - acquired infection . in this case a 58-year - old male with underlying hypertension and dyslipidaemia was admitted for acute right leg cellulitis . 
 pseudomonas aeruginosa was identified from the case , though it was not a usual suspected organism . 
 it might be due to community - acquired infection .