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

Abdul Wahab, Asrul

Rahman, M. M.

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EXCLI Journal 2013;12:997-1000 – ISSN 1611-2156 Received: November 19, 2013, accepted: November 21, 2013, published: November 29, 2013   997 Case report: PSEUDOMONAS AERUGINOSA BACTEREMIA SECONDARY  TO ACUTE RIGHT LEG CELLULITIS:  CASE OF COMMUNITY-ACQUIRED INFECTION  Asrul Abdul Wahab*, M.M. Rahman  * corresponding author: Asrul Abdul Wahab, Department of Medical Microbiology and  Immunology, Faculty of Medicine, The National University of Malaysia, Cheras 56000 Kuala Lumpur, Malaysia. Tel: +603-91455927; E-mail: asrulwahab@hotmail.com   ABSTRACT Pseudomonas aeruginosa is a gram-negative bacillus that causes wide spectrum clinical in-fections. 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.  Keywords: AmpC, bacteremia, cellulitis, community-acquired, Pseudomonas aeruginosa    INTRODUCTION Pseudomonas aeruginosa is a gram-negative bacillus that commonly colonizes hospital environment. It contaminates water and hospital devices and is known as aetio-logical agent of nosocomial infection. Community-acquired infection of this or-ganism had been reported (Hadi et al., 2007). The prevalence of P. aeruginosa bacteremia varies from one to other institu-tions and the sources of bacteremia were identified in 66 % of cases (Vitkauskiene et al., 2010). Altogether 21% of these bacteri-al infections were classified as community-acquired infection (Parkins et al., 2010).  CASE REPORT A 58-year-old Malay male with back-ground 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. It started together with the right leg swelling. 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. This was his first episode of leg swelling. There was neither chest pain nor shortness of breath. Because of that he had some difficulty while walking. On clinical examination, he was alert and conscious but febrile with body temperature of 38 °C. His blood pres-sure was normal but he was tachycardic with heart rate of 130 beats per minute. His respiratory rate was normal. Respiratory and cardiovascular system examination re-vealed no abnormality. Right leg examina-tion revealed swelling of the right leg with erythematous skin. There was no blister. There was no clear demarcation with the surrounding skin. The right leg was not gangrenous and no trauma or bite mark was seen. It was tender on palpation but there was no crepitus. The peripheral pulses were present. Ultrasound Doppler of the right leg showed no evidence of deep vein throm-bosis and no osteomyelitis changes of the EXCLI Journal 2013;12:997-1000 – ISSN 1611-2156 Received: November 19, 2013, accepted: November 21, 2013, published: November 29, 2013   998 right tibia and fibula were noted by x-ray. His total white cell count was within nor-mal limit but the neutrophil level was ele-vated. The hemoglobin and platelet level were normal. C-reactive protein was mark-edly elevated at 23.8 mg/dL. His random blood sugar was within normal range. ECG showed sinus tachycardia with no other ab-normality. The diagnosis of acute right leg cellulitis was made. Empirical antibiotics consisting of intravenous c-penicillin and cloxacillins were applied. Blood sample from the patient was sent for culture on the day of admission, grew gram-negative rods after one day of incuba-tion. These were then identified as Pseudo-monas aeruginosa based on the typical morphological features. The organism pro-duced 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 reac-tions at both butt and slant in the triple sug-ar iron agar. The organism was motile and the cytochrome oxidase was positive. The organism was an AmpC producer. The pa-tient was not responding to the empirical antibiotics and they were judiciously re-placed by intravenous cefepime 1 gram 12 hourly. Subsequently, his condition im-proved and the right leg cellulitis was grad-ually resolved. The C-reactive protein and white cell counts also were decreasing in trend as shown in Table 1. Intravenous cefepime was continued for 14 days. Re-peated blood cultures on day five of treat-ment and before discharge were negative. He was discharged well.  DISCUSSION Pseudomonas aeruginosa is a leading cause of nosocomial infection and associat-ed 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. Pseudomonas aeru-ginosa is an uncommon cause of communi-ty-acquired bacteremia. Cases of communi-ty-acquired P. aeruginosa bacteremia re-present about 21 % of all cases of P. aeru-ginosa bacteremia (Parkins et al., 2010). Community-acquired P. aeruginosa infec-tions occurred in those with specific predis-posing 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 associ-ated with community-acquired P. aerugino-sa infection.     Table 1: C-reactive protein (CRP), total white cell count and neutrophils count from day of admission (Day 1) until Day 14 Parameters Day 1 Day 3 Day 8 Day 12 Day 14 Normal range C-reactive protein (CRP) (mg/dL)  23.81  48.11   10.63  4.43  1.83  < 0.5 Total white cell count 10.1 x 109/L 11.5 x 109/L 8.9 x  109/L 10.1 x 109/L 9.3 x  109/L 4.0-10.0 x 109/L Neutrophils 9.2 x 109/L (90%) - 8.3 x 109/L (93%) 9.8 x 109/L (97%) 8.1 x 109/L (86.8%) 2.0-7.0 x 109/L    EXCLI Journal 2013;12:997-1000 – ISSN 1611-2156 Received: November 19, 2013, accepted: November 21, 2013, published: November 29, 2013   999 From hospital-based study, P. aerugino-sa accounted around 2.7 % of all bactere-mia cases and the primary source is identi-fied in 60 to 70 % of the cases, with respira-tory 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 com-mon aetiological agents for cellulitis and P. aeruginosa is not a common cause of cellu-litis (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 or-ganism can appear as primary or metastatic foci, expressed in wide presentations in-cluding cellulitis, ecthyma gangrenosum, necrotizing fascitis and gangrene (Giamerellou, 2000). Independent predic-tors of P. aeruginosa bacteremia in com-munity setting were severe immunodefi-ciency, age >90 years, receipt of antimicro-bial therapy within past 30 days, and pres-ence of central venous catheter or urinary device (Schechner et al., 2009). None of these factors was identified for our patient. 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 easi-ly develop resistance to many classes of antibiotics. P. aeruginosa is known to pos-sess many resistance genes thus it is associ-ated 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. ae-ruginosa. 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 an-tibiotic course for 14 days. Repeated blood culture showed a negative result indicating a successful treatment. AmpC overexpres-sion 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 prognosis of P. aeruginosa bacte-remia varies from one hospital to another. The 30-day mortality rate shown by a study in Japan was 20.9 % with thrombocytope-nia and polymicrobial infections as the sig-nificantly contributing factors (Horino et al., 2012). Perhaps, absence of these two factors could contribute to better outcome in our case.   CONCLUSION Pseudomonas aeruginosa is not a com-mon 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 immuno-suppressant. Treatment of Pseudomonas aeruginosa infection is always challenging as the organism easily acquires resistance to different classes of antibiotics.   Acknowledgement: Authors thank the Dean of the Faculty of Medicine and the Head of the Department of Medical Micro-biology and Immunology, The National University of Malaysia for cooperation and help.  REFERENCES Cabot G, Alain A, Ocampo-Sosa, Tubau F, Macia MD, Rodriguez C et al. Overexpres-sion of AmpC and efflux pumps in Pseu-domonas aeruginosa isolates from blood-stream infections: Prevalence and impact on resistance in a Spanish multicenter study. Antimicrob Agents Chemother 2011;55: 1906-11.  Dryden MS. Skin and soft tissue infection: microbiology and epidemiology. Int J An-timicrob Agents 2009;34:S2-S7. EXCLI Journal 2013;12:997-1000 – ISSN 1611-2156 Received: November 19, 2013, accepted: November 21, 2013, published: November 29, 2013   1000 Fazlul MKK, Zaini MZ, Rashid MA, Na-zmul MHM. Antibiotic susceptibility pro-files of clinical isolates of Pseudomonas aeruginosa from Selayang Hospital, Malay-sia. Biomed Res 2011;22:263-6.  Giamerellou H. Therapeutic guideline for Pseudomonas aeruginosa infections. Int J Antimicrob Agents 2000;16:103-6.  Hadi U, Chaar M, Jaafar RF, Matar GM. Comparative analysis of hospital acquired and community acquired Pseudomonas ae-ruginosa strains in tertiary care medical center. J Appl Res2007;7:233-7.  Horino T, Chiba A, Kawano S, Kato T, Sa-to F, Maruyama Y et al. Clinical character-istics and risk factors for mortality in pa-tients with bacteremia caused by Pseudo-monas aeruginosa. Intern Med 2012;51: 59-64.  Parkins MD, Gregson DB, Pitout JDD, Ross T, Laupland KB. Population-based study of the epidemiology and the risk fac-tors for Pseudomonas aeruginosa blood-stream infection. Infection 2010;38:25-32.  Schechner V, Nobre V, Kaye KS, Leshno M, Giladi M, Rohner P et al. Gram-negative bacteremia upon hospital admis-sion: When should Pseudomonas aerugino-sa be suspected? Clin Infect Dis 2009;48:580-6.  Tam VH, Schilling AN, LaRocco MT, Gen-try LO, Lolans K, Quinn JP et al. 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Pseudomonas aeruginosa bacteremia secondary to acute right leg cellulitis

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Pseudomonas aeruginosa bacteremia secondary to acute right leg cellulitis

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