Vol. 17, No. 38
THE JOHNS HOPKINS MICROBIOLOGY NEWSLETTER
Monday, October 19, 1998
10/5-10/9 - 10 outbreaks: 4 gastroenteritis at food service organizations/restaurants
1 respiratory (Legionella), 3 scabies, 1 influenza-like illness (first of this flu season) 1 Group A strep. 10/12-10/16 - 3 outbreaks: 1 influenza-like illness; 1 conjunctivitis; and 1 scabies
Case report: This 68 year old man with a history of chronic active hepatitis B cirrhosis, renal insufficiency and development of lower extremity edema and mild ascites over the last two years presents with increasing abdominal girth, worsening lower extremity edema and confusion. The patient was recently admitted to an outside hospital with similar symptoms and concomitant fever. He was treated with a course of antibiotics, which were completed two days prior to the current presentation. Additionally, this patient was admitted to The Johns Hopkins Hospital three months ago with fever and worsening ascites and was found to have a spontaneous bacterial peritonitis that grew Streptococcus viridans on day four of culture. He was treated with a seven day course of IV cefotaxime to which he responded well. On this admission the patient was afebrile and the physical exam was notable for the following: marked abdominal distention with tense ascites; 4+ pitting edema of the lower extremities to the level of the hips; slow speech with a mini-mental status exam score of 12/24; and mild asterixis. Pertinent labs included the following: WBC 4.4 with a normal differential; Hct 31; BUN 27; Cr 2.4; AST 50; alk phos 122; INR 1.6. An abdominal paracentesis was performed and yielded 10 liters of fluid. Microscopic examination of the peritoneal fluid revealed moderate PMNs, but no organisms were seen with Gram stain. Aerobic and anaerobic culture bottles were positive at one day and preliminary identification showed Gram-negative rods. Two colony morphologies grew on blood agar plates and both were oxidase positive. Final identification revealed two strains of Pseudomonas stutzeri with distinct susceptibility patterns.
Organism and Laboratory Diagnosis: Pseudomonas stutzeri is an aerobic, nonfermentative, gram-negative rod with a polar monotrichous flagella. P. stutzeri is a ubiquitous saprophyte found in soil, water and hospital environments.
On sheep blood agar, isolated strains of P. stutzeri produce dry, wrinkled, tough, adherent colonies, usually light brown. P. stutzeri is identified using the following criteria: presence of oxidase, ability to oxidize but not ferment dextrose, ability to reduce nitrate to gas, growth on MacConkey agar, and demonstration of motility by polar flagella.
Clinical Manifestations: P. stutzeri is uncommonly isolated from patients and is rarely associated with disease. In most cases, isolation of P. stutzeri represents contamination or colonization in hospitalized patients. The most common reported sites of clinical isolates are from surgical wounds, blood, the respiratory tract, and urine. Several cases of bacteremia were reported in patients undergoing hemodialysis and P. stutzeri was subsequently isolated from the dialysate in the dialysis machine. The ultimate source was the deionized water used to form the dialysate. Contaminated intravenous fluids have also been implicated in P. stutzeri septicemia in hospitalized patients. If a number of isolates appear at the same time in a hospital setting, the possibility of contamination with water or soap should be considered and pursued.
P. stutzeri is usually considered a contaminant, but in rare cases the organism can become an opportunistic pathogen when host defense mechanisms are weakened. There have been several case reports of community-acquired pnuemonia, one associated with empyema and one case of bacterial meningitis due to P. stutzeri. In each case described the patients had underlying conditions or predisposing risk factors for disease such as chemotherapy, COPD, chronic liver disease, or HIV infection.
Treatment: P. stutzeri is highly susceptible to antibiotics and clinical response to treatment with antibiotics effective for other Gram-negative bacteria is generally good. In vitro studies have shown that isolates of P. stutzeri are generally susceptible to aminoglycosides, carbapenems, monobactams, antipseudomonal penicillins, trimethoprim-sulfamethoxazole, and third-generation cephalosporins, and are variably susceptible to ampicillin.
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2. Campos-Herrero MI, Bordes A, Rodriguez H et al: Pseudomonas stutzeri Community-Acquired Pneumonia Associated with Empyema: Case Report and Review. CID 1997;25:325-326.
3. Goetz A, Yu VL, Hanchett JE et al: Pseudomonas stutzeri Bacteremia Associated with Hemodialysis. Arch Intern Med 1983;143:1909-12.
4. Roig P, Orti A, Navarro V: Meningitis Due to Pseudomonas stutzeri in a Patient Infected with Human Immunodeficiency Virus. CID 1996;22:587-8.