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Ochrobactrum anthropi bacteremia
CASE STUDIES IN INFECTIOUS DISEASE
Ochrobactrum anthropi bacteremia Nazanin Jelveh, MD, and Burke A. Cunha, MD, Mineola and Stony Brook, N.Y. Ochrobactrum anthropi (O. anthropi), formerly known as Achromobacter CDC group Vd, is a gram-negative bacillus that is aerobic, oxidase producing, and nonlactose fermenting. This organism has been found in environmental and hospital water sources and has pathogenic potential in humans. Most reports in the literature of O. anthropi bacteremia are associated with intravenous line infections. We describe a case of bacteremia with O. anthropi in a 33-month-old boy with acute osteomyelitis. O. anthropi bacteremia also has been reported in immunocompromised hosts. Rarely, O. anthropi has been a cause of soft tissue or bone infection. (Heart Lung® 1999;28:145-6)
O
chrobactrum anthropi is a gram-negative, nonfermenting, oxidase-positive bacillus formerly known as Achromobacter CDC group Vd.1-3 This organism has been found in hospital and environmental water sources.2,4 O. anthropi resembles the Pseudomonas species in that it is water borne and may cause nosocomial infec-tion. In addition, both species are gram-negative, nonlactose-fermenting bacilli, and both grow well on MacConkey agar.5 O. anthropi differs from pseudomonads in that it lacks pigment production and has peritrichous flagella.4 In our review of the literature, we have found several case series and reports about bacteremia with O. anthropi, especially in patients with immunosuppression and central venous access.3-10 A case of puncture wound osteochondritis of the foot as a result of this organism has been described as well. We describe a case of O. anthropi bacteremia in a 33-month-old boy with left femur osteomyelitis.
CASE REPORT A 33-month-old boy with left leg pain and fever was brought to the emergency department. His left leg pain started approximately 2 days before admission and was associated with limping. He had a fever as high as 105.6°F; he had pain so severe that he cried every time he walked. There was some relief of the pain with ibuprofen. Outpatient radiographs of the left leg and hip were negative. Medical history was significant for asthma and pneumonia at age one and a half. The patient was taking From the Infectious Disease Division, Winthrop-University Hospital, Mineola, and the State University of New York School of Medicine, Stony Brook. Reprint requests: Burke A. Cunha, MD, Chief, Infectious Disease Division, Winthrop-University Hospital, Mineola, NY 11501. Copyright © 1999 by Mosby, Inc. 0147-9563/99/$8.00 + 0 2/1/94602
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ibuprofen for leg pain and fever and Proventil nebulizer as needed. There were no known drug allergies. On physical examination, the child was sitting comfortably in his father’s lap. His skin was warm and dry with no rashes. There was a small red spot in the right eye with no exudate. The ears, nose, and throat were normal. The neck was supple. There was no lymph-adenopathy. The lungs were clear to auscultation bilaterally, and the heart sounds were tachycardic at a rate of 160 beats per minute, with a 1-over-6 systolic murmur at the left sternal border. The abdomen was soft, nontender, and nondistended, with normoactive bowel sounds. There was diminished external rotation in the left hip joint. The patient appeared to walk with a limp. The neurologic examination was within normal limits. Laboratory testing revealed a white blood cell count of 13,600 k/mm3, (66% segmented neutrophils, 27% lymphocytes, and 6% monocytes). The hemoglobin was 10.6 g/dL; the hematocrit was 33.0%; and the platelet count was 404,000/mm3. The electrolyte levels and renal function were within normal limits. The erythrocyte sedimentation rate was 80 mm/hr, and the C-reactive protein was 5.08 mg/dL. The patient was admitted, and intravenous fluids and cefazolin were started empirically for possible osteomyelitis or septic arthritis of the left hip. An MRI of the left leg and hip, obtained on the day of admission, revealed abnormal marrow signal intensity and deep soft tissue edema in the left proximal femoral metaphysis. A bone scan revealed osteomyelitis in the left proximal femur. One set of blood cultures from hospital day 1 and one from hospital day 2 grew methicillin-resistant Staphylococcus aureus (MRSA). On hospital day 3, antibiotics were changed from cefazolin to clindamycin and rifampin, and the patient’s condition improved. On hospital day 5, another set of blood cultures was drawn. The organism was found to be a gram-negative bacillus able to grow on MacConkey agar, despite the fact that it appeared as a gram-positive rod on Gram
145
Ochrobactrum anthropi bacteremia stain. Because the patient was doing better clinically, the decision was made to observe him. Eventually, the organism was identified as O. anthropi. The organism was sensitive only to TMP-SMX, levofloxacin, and gentamicin. Repeated blood cultures from hospital day 7 were negative for gram-negative organisms. A nasal culture was negative for MRSA. The patient was discharged after placement of a Broviac catheter for home antibiotic therapy with clindamycin and rifampin for a 6-week total course.
DISCUSSION Unusual organisms that were not thought to have pathogenic potential are emerging now as causes of serious infections, especially in immunocompromised hosts. O. anthropi is an example. O. anthropi has been associated with the genus Achromobacter. It often has been associated with 3 other organisms: A. xylosoxidans, A. radiobacter, and Achromobacter group B. O. anthropi must be differentiated from these organisms. All 4 are motile, gramnegative organisms that produce oxidase and catalase and grow on MacConkey agar. Compared with the other 3, O. anthropi weakly produces acid from glucose and xylose, hydrolyzes urea, does not hydrolyze esculin, and does not grow on cetrimide.5 The gram variability, as has been described in our case, has been reported in the past.1 O. anthropi produces minute colonies at 25 hours, with progression to moderate-sized and very mucoid colonies within 48 hours. On Gram stain, this organism can have a swollen hook shape at one end and monopolar flagella.1 The source of O. anthropi has been thought to be the water in the environment or hospital, similar to Pseudomonas, Agrobacterium, and Alcaligenes. Since it was first described in the form of a pancreatic abscess in 1980, O. anthropi has presented in many different forms. From our review of the literature, several catheter-associated bacteremias have been described in immunocompromised patients who have had central venous catheters. The first reported case occurred in 1984 in a 16-year-old girl with Hodgkin’s disease.3 The next case was reported in 1992 in a 3-year-old with retinoblastoma.5 All 7 of the cases reported in 1992 were associated with central venous catheters. Other reports since then also found a strong association between O. anthropi and central venous catheters.6-10 Contaminated rabbit antithymocyte globulin has been implicated in one article as a source for O. anthropi bacteremia in patients who underwent transplantation.8 Localized infections with O. anthropi have been described. An example is a case of puncture wound osteochondritis of the foot caused by O. anthropi.2 A
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more recent article reported 3 cases of localized infection with this organism in the bile, sputum, and a foot wound.4 O. anthropi bone infections also have been reported.11-13 Without a culture of the infected bone, the cause of the osteomyelitis in our patient is uncertain. The first 2 blood cultures grew MRSA. The possibility of skin colonization, with MRSA being introduced into the blood culture, is possible; but the nares culture for MRSA was negative, which argues against this explanation. The third blood was drawn. The possibility of a peripheral line as a mechanism of introducing O. anthropi has not been reported. It cannot be proven in our patient because the line tip was not cultured, but it remains as a possible explanation. Although intravenous line infection and osteomyelitis are diagnostic possibilities, it must be emphasized that in a small but definitive number of patients with O. anthropi bacteremia, the source of the bacteremia is never found. Though our patient could have had an O. anthropi line infection or osteomyelitis, it is not likely that he represents a case of O. anthropi bacteremia of undetermined source. REFERENCES 1. Chester B, Cooper LH. Achromobacter species (CDC group Vd): morphological and biochemical characterization. J Clin Microbiol 1979;9:425-36. 2. Barson WJ, Cromer BA, Marcon MJ. Puncture wound osteochondritis of the foot caused by CDC group Vd. J Clin Microbiol 1987;25:2014-6. 3. Kish MA, Buggy PB, Forbes BA. Bacteremia caused by Achromobacter species in an immunocompromised host. J Clin Microbiol 1984;19:947-8. 4. Gill MV, Ly H, Mueenuddin M, Schoch PE, Cunha BA. Intravenous line infection due to Ochrobactrum anthropi (CDC group Vd) in a normal host. Heart Lung 1997;26:335-6. 5. Cieslak TJ, Robb M, Drabick CJ, Fischer GW. Catheter-associated sepsis caused by Ochrobactrum anthropi: report of a case and review of related nonfermentative bacteria. Clin Infect Dis 1992;14:902-7. 6. Gransden WR, Eykyn SJ. Seven cases of bacteremia due to Ochrobactrum anthropi. Clin Infect Dis 1992;15:1068-9. 7. Kern WV, Oethinger M, Kaufhold A, Rozdzinski E, Marre R. Ochrobactrum anthropi bacteremia: report of four cases and short review. Infection 1993;21:306-10. 8. Ezzedine H, Mourad M, Van Ossel C, Logghe C, Squifflet JP, Renault F, et al. An outbreak of Ochrobactrum anthropi bacteremia in five organ transplant patients. J Hosp Infect 1994;27:35-42. 9. Gill MV, Klein NC, Cunha BA. Unusual organisms causing intravenous line infections in compromised hosts; I: bacterial and algal infections. Infect Dis Clin Pract 1996;5:244-55. 10. Cieslak TJ, Drabnick CJ, Robb ML. Pyogenic infections due to Ochrobactrum anthropi. Clin Infect Dis 1996;22:845-7. 11. Hoddy DM, Barton LL. Puncture wound–induced Achromobacter xylosoxidans osteomyelitis of the foot. Am J Dis Child 1991;145:599-600. 12. Barton LL, Hoddy DM. Osteomyelitis due to Achromobacter xylosoxidans. Clin Infect Dis 1993;17:296-7. 13. Walsh RD, Klein NC, Cunha BA. Achromobacter xylosoxidans osteomyelitis. Clin Infect Dis 1993;16:176-8.
MARCH/APRIL 1999
HEART & LUNG
Ochrobactrum anthropi bacteremia Nazanin Jelveh, MD, and Burke A. Cunha, MD, Mineola and Stony Brook, N.Y. Ochrobactrum anthropi (O. anthropi), formerly known as Achromobacter CDC group Vd, is a gram-negative bacillus that is aerobic, oxidase producing, and nonlactose fermenting. This organism has been found in environmental and hospital water sources and has pathogenic potential in humans. Most reports in the literature of O. anthropi bacteremia are associated with intravenous line infections. We describe a case of bacteremia with O. anthropi in a 33-month-old boy with acute osteomyelitis. O. anthropi bacteremia also has been reported in immunocompromised hosts. Rarely, O. anthropi has been a cause of soft tissue or bone infection. (Heart Lung® 1999;28:145-6)
O
chrobactrum anthropi is a gram-negative, nonfermenting, oxidase-positive bacillus formerly known as Achromobacter CDC group Vd.1-3 This organism has been found in hospital and environmental water sources.2,4 O. anthropi resembles the Pseudomonas species in that it is water borne and may cause nosocomial infec-tion. In addition, both species are gram-negative, nonlactose-fermenting bacilli, and both grow well on MacConkey agar.5 O. anthropi differs from pseudomonads in that it lacks pigment production and has peritrichous flagella.4 In our review of the literature, we have found several case series and reports about bacteremia with O. anthropi, especially in patients with immunosuppression and central venous access.3-10 A case of puncture wound osteochondritis of the foot as a result of this organism has been described as well. We describe a case of O. anthropi bacteremia in a 33-month-old boy with left femur osteomyelitis.
CASE REPORT A 33-month-old boy with left leg pain and fever was brought to the emergency department. His left leg pain started approximately 2 days before admission and was associated with limping. He had a fever as high as 105.6°F; he had pain so severe that he cried every time he walked. There was some relief of the pain with ibuprofen. Outpatient radiographs of the left leg and hip were negative. Medical history was significant for asthma and pneumonia at age one and a half. The patient was taking From the Infectious Disease Division, Winthrop-University Hospital, Mineola, and the State University of New York School of Medicine, Stony Brook. Reprint requests: Burke A. Cunha, MD, Chief, Infectious Disease Division, Winthrop-University Hospital, Mineola, NY 11501. Copyright © 1999 by Mosby, Inc. 0147-9563/99/$8.00 + 0 2/1/94602
HEART & LUNG
VOL. 28, NO. 2
ibuprofen for leg pain and fever and Proventil nebulizer as needed. There were no known drug allergies. On physical examination, the child was sitting comfortably in his father’s lap. His skin was warm and dry with no rashes. There was a small red spot in the right eye with no exudate. The ears, nose, and throat were normal. The neck was supple. There was no lymph-adenopathy. The lungs were clear to auscultation bilaterally, and the heart sounds were tachycardic at a rate of 160 beats per minute, with a 1-over-6 systolic murmur at the left sternal border. The abdomen was soft, nontender, and nondistended, with normoactive bowel sounds. There was diminished external rotation in the left hip joint. The patient appeared to walk with a limp. The neurologic examination was within normal limits. Laboratory testing revealed a white blood cell count of 13,600 k/mm3, (66% segmented neutrophils, 27% lymphocytes, and 6% monocytes). The hemoglobin was 10.6 g/dL; the hematocrit was 33.0%; and the platelet count was 404,000/mm3. The electrolyte levels and renal function were within normal limits. The erythrocyte sedimentation rate was 80 mm/hr, and the C-reactive protein was 5.08 mg/dL. The patient was admitted, and intravenous fluids and cefazolin were started empirically for possible osteomyelitis or septic arthritis of the left hip. An MRI of the left leg and hip, obtained on the day of admission, revealed abnormal marrow signal intensity and deep soft tissue edema in the left proximal femoral metaphysis. A bone scan revealed osteomyelitis in the left proximal femur. One set of blood cultures from hospital day 1 and one from hospital day 2 grew methicillin-resistant Staphylococcus aureus (MRSA). On hospital day 3, antibiotics were changed from cefazolin to clindamycin and rifampin, and the patient’s condition improved. On hospital day 5, another set of blood cultures was drawn. The organism was found to be a gram-negative bacillus able to grow on MacConkey agar, despite the fact that it appeared as a gram-positive rod on Gram
145
Ochrobactrum anthropi bacteremia stain. Because the patient was doing better clinically, the decision was made to observe him. Eventually, the organism was identified as O. anthropi. The organism was sensitive only to TMP-SMX, levofloxacin, and gentamicin. Repeated blood cultures from hospital day 7 were negative for gram-negative organisms. A nasal culture was negative for MRSA. The patient was discharged after placement of a Broviac catheter for home antibiotic therapy with clindamycin and rifampin for a 6-week total course.
DISCUSSION Unusual organisms that were not thought to have pathogenic potential are emerging now as causes of serious infections, especially in immunocompromised hosts. O. anthropi is an example. O. anthropi has been associated with the genus Achromobacter. It often has been associated with 3 other organisms: A. xylosoxidans, A. radiobacter, and Achromobacter group B. O. anthropi must be differentiated from these organisms. All 4 are motile, gramnegative organisms that produce oxidase and catalase and grow on MacConkey agar. Compared with the other 3, O. anthropi weakly produces acid from glucose and xylose, hydrolyzes urea, does not hydrolyze esculin, and does not grow on cetrimide.5 The gram variability, as has been described in our case, has been reported in the past.1 O. anthropi produces minute colonies at 25 hours, with progression to moderate-sized and very mucoid colonies within 48 hours. On Gram stain, this organism can have a swollen hook shape at one end and monopolar flagella.1 The source of O. anthropi has been thought to be the water in the environment or hospital, similar to Pseudomonas, Agrobacterium, and Alcaligenes. Since it was first described in the form of a pancreatic abscess in 1980, O. anthropi has presented in many different forms. From our review of the literature, several catheter-associated bacteremias have been described in immunocompromised patients who have had central venous catheters. The first reported case occurred in 1984 in a 16-year-old girl with Hodgkin’s disease.3 The next case was reported in 1992 in a 3-year-old with retinoblastoma.5 All 7 of the cases reported in 1992 were associated with central venous catheters. Other reports since then also found a strong association between O. anthropi and central venous catheters.6-10 Contaminated rabbit antithymocyte globulin has been implicated in one article as a source for O. anthropi bacteremia in patients who underwent transplantation.8 Localized infections with O. anthropi have been described. An example is a case of puncture wound osteochondritis of the foot caused by O. anthropi.2 A
146
Jelveh and Cunha
more recent article reported 3 cases of localized infection with this organism in the bile, sputum, and a foot wound.4 O. anthropi bone infections also have been reported.11-13 Without a culture of the infected bone, the cause of the osteomyelitis in our patient is uncertain. The first 2 blood cultures grew MRSA. The possibility of skin colonization, with MRSA being introduced into the blood culture, is possible; but the nares culture for MRSA was negative, which argues against this explanation. The third blood was drawn. The possibility of a peripheral line as a mechanism of introducing O. anthropi has not been reported. It cannot be proven in our patient because the line tip was not cultured, but it remains as a possible explanation. Although intravenous line infection and osteomyelitis are diagnostic possibilities, it must be emphasized that in a small but definitive number of patients with O. anthropi bacteremia, the source of the bacteremia is never found. Though our patient could have had an O. anthropi line infection or osteomyelitis, it is not likely that he represents a case of O. anthropi bacteremia of undetermined source. REFERENCES 1. Chester B, Cooper LH. Achromobacter species (CDC group Vd): morphological and biochemical characterization. J Clin Microbiol 1979;9:425-36. 2. Barson WJ, Cromer BA, Marcon MJ. Puncture wound osteochondritis of the foot caused by CDC group Vd. J Clin Microbiol 1987;25:2014-6. 3. Kish MA, Buggy PB, Forbes BA. Bacteremia caused by Achromobacter species in an immunocompromised host. J Clin Microbiol 1984;19:947-8. 4. Gill MV, Ly H, Mueenuddin M, Schoch PE, Cunha BA. Intravenous line infection due to Ochrobactrum anthropi (CDC group Vd) in a normal host. Heart Lung 1997;26:335-6. 5. Cieslak TJ, Robb M, Drabick CJ, Fischer GW. Catheter-associated sepsis caused by Ochrobactrum anthropi: report of a case and review of related nonfermentative bacteria. Clin Infect Dis 1992;14:902-7. 6. Gransden WR, Eykyn SJ. Seven cases of bacteremia due to Ochrobactrum anthropi. Clin Infect Dis 1992;15:1068-9. 7. Kern WV, Oethinger M, Kaufhold A, Rozdzinski E, Marre R. Ochrobactrum anthropi bacteremia: report of four cases and short review. Infection 1993;21:306-10. 8. Ezzedine H, Mourad M, Van Ossel C, Logghe C, Squifflet JP, Renault F, et al. An outbreak of Ochrobactrum anthropi bacteremia in five organ transplant patients. J Hosp Infect 1994;27:35-42. 9. Gill MV, Klein NC, Cunha BA. Unusual organisms causing intravenous line infections in compromised hosts; I: bacterial and algal infections. Infect Dis Clin Pract 1996;5:244-55. 10. Cieslak TJ, Drabnick CJ, Robb ML. Pyogenic infections due to Ochrobactrum anthropi. Clin Infect Dis 1996;22:845-7. 11. Hoddy DM, Barton LL. Puncture wound–induced Achromobacter xylosoxidans osteomyelitis of the foot. Am J Dis Child 1991;145:599-600. 12. Barton LL, Hoddy DM. Osteomyelitis due to Achromobacter xylosoxidans. Clin Infect Dis 1993;17:296-7. 13. Walsh RD, Klein NC, Cunha BA. Achromobacter xylosoxidans osteomyelitis. Clin Infect Dis 1993;16:176-8.
MARCH/APRIL 1999
HEART & LUNG