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Etiological Misidentification by Routine Biochemical Tests of Bacteremia Caused by Gordonia terrae Infection in the Course of an Episode of
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     Microbiology Department, Hospital San Rafael, Las Jubias 82, 15006 A Corua, Spain

    Internal Medicine, Hospital San Rafael, Las Jubias 82, 15006 A Corua, Spain

    Pathology Department, Hospital San Rafael, Las Jubias 82, 15006 A Corua, Spain

    Instituto Valenciano de Microbiología, Masia El Romeral, Ctra. de Betera a San Antonio Km. 0.3, 46117 Betera, Valencia, Spain

    ABSTRACT

    Gordonia terrae has been reported to be a rare cause of bacteremia. We report the first case of bacteremia associated with acute cholecystitis. Commercial biochemical testing was not able to identify the strain at the genus level, classifying it instead as Rhodococcus sp. Definitive identification was obtained by sequencing of the 16S rRNA gene.

    CASE REPORT

    A 61-year-old male patient with longstanding hepatitis C, hypertension, and calculous gallbladder presented with a fever (38.5°C) of 2 days' duration, lack of urinary sphincter control, and altered mental status, without other accompanying signs/symptoms at admission. Serum and urine laboratory data were unremarkable, a thorax chest film was normal, and abdominal sonographic findings consisted of dilated lumen of gallbladder and the presence of stones. Pretreatment cerebrospinal fluid and blood samples were taken for culturing, and antibiotic treatment with intravenous piperacillin-tazobactam (4 g every 8 h for 20 days) plus intravenous gentamicin (240 mg every 24 h for the first 4 days) was initiated due to a clinical diagnosis of acute cholecystitis. During the antibiotic course, the patient remained apyretic and asymptomatic. Afterward, cholecystectomy was performed; the gallbladder, of 11 by 6.5 cm, was sent to the laboratory for pathological study; and a bile sample was collected for culturing. After being discharged from the hospital, the patient remained asymptomatic upon outpatient follow-up.

    Cerebrospinal fluid samples taken at admission showed no biochemical alterations, and culturing yielded no bacterial growth. The blood culture set taken at admission was incubated in BACTEC 9050 (Becton Dickinson, Cockeysville, Md.). On the fourth day of incubation, the aerobic bottle was positive for growth and subcultures in chocolate agar incubated at 37°C under aerobiosis with 5% CO2 were performed. After 72 h, smooth, salmon-pink, catalase-positive and oxidase-negative colonies were obtained. Microscopic examination showed gram-positive coccobacilli that were negative for Ziehl-Neelsen staining. API CORYNE (bioMerieux, Marcy-l'Etoile, France) was used for initial identification. The isolate gave a profile number of 1110004 and was identified as Rhodococcus sp. (98.1% identification; T index, 0.94). The strain was sent to the reference laboratory at Instituto Valenciano de Microbiología for further analysis.

    Cultures of bile samples taken at surgery after 20 days of piperacillin-tazobactam treatment were negative.

    Macroscopic and histological examination of the gallbladder wall revealed intense ulceration, calcification areas, adherences of external surfaces to hepatic tissues, and moderate acute and chronic inflammation. A stone of 3 by 1.5 cm was found. A definite diagnosis of acute and chronic cholecystitis was made.

    At the reference laboratory, the metabolic characteristics of the strain, determined by standard methods (3), were acid production from mannitol, rhamnose, galactose, raffinose, sorbitol, and citrate; hydrolysis of urea and esculin; reduction of nitrates; absence of beta-galactosidase; and absence of growth in lysozyme broth. With Kinyoun stain, a weakly acid-fast nature was shown. The following phenotypic identifications were discarded for the indicated reasons: Corynebacterium sp. and Rhodococcus sp., based on the weakly acid-fast nature of the strain; Tsukamurella sp., due to the absence of beta-galactosidase, the absence of growth in lysozyme broth, and the strain's capability for nitrate reduction; and Nocardia sp., due to the absence of beta-galactosidase, the absence of growth in lysozyme broth, and the absence of aerial filaments.

    The strain was presumptively identified as Gordonia terrae based on colony characteristics and the profile of utilization of sugars as the sole carbon source. Due to the very infrequent isolation rate of G. terrae in human specimens by clinical microbiology laboratories, the strain was finally identified by genomic DNA extraction from pure culture colonies and sequence analysis of the 16S rRNA gene (10). Bacterial DNA was extracted, amplified with previously described primers (17), and gel purified by using the QIAquick PCR purification kit (QIAGEN, Hilden, Germany). Sequencing was performed with an ABI Prism 310 automated sequencer (Perkin-Elmer Applied Biosystems, Foster City, Calif.). The nucleotide sequence was analyzed with the use of a BLAST search of the National Institutes of Health GenBank database (BLASTN, version 2.2.13). The strain was definitively identified as G. terrae, as 100% similarity with the G. terrae type strain (sequence accession no. DQ180334, corresponding to strain NML88-1049) was obtained. Susceptibility tests were performed by agar dilution in Mueller-Hinton agar according to CLSI guidelines for aerobes (6). MICs were 0.03, 0.25, 0.125, 0.015, and 0.25 μg/ml for penicillin, vancomycin, cefotaxime, piperacillin-tazobactam, and gentamicin, respectively.

    Hepatitis C virus infection facilitates gallstone formation (5). The diagnosis of obstructive cholecystitis is based on clinical and sonographic findings with specificity and sensitivity values of greater than 90% (12), as other signs, such as moderate temperature elevation and minimal icterus, may not occur. Moreover, laboratory data are rarely required for diagnosis because there are usually only moderately elevated leukocyte counts, and mild elevations in bilirubin, aspartate aminotransferase, alkaline phosphatase, and serum amylase occur in only 50%, 40%, 25%, and 10% of patients, respectively (12). Elderly patients with calculous cholecystitis appear to be more susceptible to the presence of bacteria in bile (12) and bacteremia (9). The presence of bacteria in bile is assumed to occur via an ascending route from the duodenum, when high bacterial counts occur transiently after meals under conditions that allow overgrowth. Elderly patients and/or those with infectious complications should be treated early for infection; piperacillin plus an aminoglycoside is an appropriate initial antibiotic regimen (12), and delayed surgery has been advocated based on the conservative management opinion that morbidity is thereby decreased (12).

    The bacterial genus Gordonia includes 21 species (www.bacterio.cict.fr) of mycolic acid-containing actinomycetes and belongs to the supragenic group, which also includes the genera Mycobacterium, Corynebacterium, Nocardia, Rhodococcus, Tsukamurella, and Dietzia (8). Gordonia species have been isolated from the environment and from the intestinal contents of mammals (3). To our knowledge, 11 infections by G. terrae have been previously described: six catheter-related bacteremias (4, 11, 13), two brain abscesses (7, 8), one skin infection with lymphadenitis (11), one mycetoma (1), and one granulomatous mastitis (18). The isolation of Gordonia strains requires 3 to 4 days of incubation; this delay can provide false-negative results and underestimations of infections caused by this genus (14) and can lead to easy confusion with Rhodococcus spp., with no single commercially available biochemical testing kit able to differentiate them (13, 15). Penicillins and aminoglycosides are active against Gordonia species (2), and treatment of previous bacteremias caused by species from this genus suggests that a combination of penicillins and aminoglycosides can be a suitable therapy (14).

    Here, we describe a G. terrae bacteremia in the course of an episode of acute cholecystitis (the definitive anatomopathological diagnosis) in a patient with chronic cholecystitis and hepatitis C successfully treated with piperacillin-tazobactam (20 days) plus gentamicin (4 days). G. terrae was isolated only from the one blood culture set taken prior to treatment initiation; it was not recovered from the surgical specimen. The lack of isolation in the bile sample may be due to the high susceptibility of the isolate (consistent with the susceptibility of a G. terrae isolate reported previously [13]), as well as to the antibiotics used as treatment (MIC of piperacillin-tazobactam, 0.015 μg/ml) and to the length of the treatment prior to cholecystectomy. Previous reports of patients undergoing cholecystectomy have shown very high mean concentrations of piperacillin-tazobactam in serum (69.1-9.9 μg/ml, respectively), in gallbladder bile (342.3-7.7 μg/ml, respectively), and in the gallbladder wall (49.3-2.9 μg/ml, respectively) after a single dose of 4 g of piperacillin and 0.5 g of tazobactam (16).

    The small reported number of infections by Gordonia species, together with the time-consuming, labor-intensive, and inconclusive results of biochemical identifications of aerobic actinomycetes, suggest the need for methods such as 16S rRNA sequencing for definitive identification (15). The fact that these highly complex methods rely on specialized equipment, facilities, and personnel suggests that suspected isolates should be sent to reference laboratories (14).

    FOOTNOTES

    REFERENCES

    Bakker, X. R., P. H. Spauwen, and W. M. Dolmans. 2004. Mycetoma of the hand caused by Gordona terrae: a case report. J. Hand Surg. (Br.) 29:188-190.

    Boiron, P., and F. Provost. 1990. Characterization of Nocardia, Rhodococcus and Gordona species by in vitro susceptibility testing. Zentbl. Bakteriol. 274:203-213.

    Brown, J. N., M. M. McNeil, and E. P. Desmond. 1999. Nocardia, Rhodococcus, Gordona, Actinomadura, Streptomyces, and other actinomycetes of medical importance, p. 370-398. In P. R. Murray, E. J. Baron, M. A. Pfaller, F. C. Tenover, and R. H. Yolken (ed.), Manual of clinical microbiology, 7th ed. ASM Press, Washington, D.C.

    Buchman, A. L., M. M. McNeil, J. M. Brown, B. A. Lasker, and M. E. Ament. 1992. Central venous catheter sepsis caused by unusual Gordona (Rhodococcus) species: identification with a digoxigenin-labeled rDNA probe. Clin. Infect. Dis. 15:694-697.

    Chang, T. S., S. K. Lo, H. Y. Shyr, J. T. Fang, W. C. Lee, D. I. Tai, I. S. Sheen, D. Y. Lin, C. M. Chu, and Y. F. Liaw. 2005. Hepatitis C virus infection facilitates gallstone formation. J. Gastroenterol. Hepatol. 20:1416-1421.

    Clinical and Laboratory Standards Institute. 2006. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard, 7th ed. CLSI document M7-A7. Clinical and Laboratory Standards Institute, Wayne, Pa.

    Drancourt, M., M. M. McNeil, J. M. Brown, B. A. Lasker, M. Maurin, M. Choux, and D. Raoult. 1994. Brain abscess due to Gordona terrae in an immunocompromised child: case report and review of infections caused by G. terrae. Clin. Infect. Dis. 19:258-262.

    Drancourt, M., J. Pelletier, A. A. Cherif, and D. Raoult. 1997. Gordona terrae central nervous system infection in an immunocompetent patient. J. Clin. Microbiol. 35:379-382.

    Hacker, K. A., C. C. Schultz, and T. S. Helling. 1990. Choledochotomy for calculous disease in the elderly. Am. J. Surg. 160:610-612.

    Han, X. Y., A. S. Pham, J. J. Tarrand, P. K. Sood, and R. Luthra. 2002. Rapid and accurate identification of mycobacteria by sequencing hypervariable regions of the 16S ribosomal RNA gene. Am. J. Clin. Pathol. 118:796-801.

    Lesens, O., Y. Hansmann, P. Riegel, R. Heller, M. Benaissa-Djellouli, M. Martinot, H. Petit, and D. Christmann. 2000. Bacteremia and endocarditis caused by a Gordonia species in a patient with a central venous catheter. Emerg. Infect. Dis. 6:382-385.

    Levison, M. E., and L. M. Bush. 1995. Peritonitis and other intra-abdominal infections, p. 705-740. In G. L. Mandell, J. E. Bennett, and R. Dolin (ed.), Principles and practice of infectious diseases, 4th ed. Churchill Livingstone, New York, N.Y.

    Pham, A. S., I. De, K. V. Rolston, J. J. Tarrand, and X. Y. Han. 2003. Catheter-related bacteremia caused by the nocardioform actinomycete Gordonia terrae. Clin. Infect. Dis. 36:524-527.

    Riegel, P., R. Ruimy, D. de Briel, F. Eichler, J. P. Bergerat, R. Christen, and H. Monteil. 1996. Bacteremia due to Gordona sputi in an immunocompromised patient. J. Clin. Microbiol. 34:2045-2047.

    Sng, L. H., T. H. Koh, S. R. Toney, M. Floyd, W. R. Butler, and B. H. Tan. 2004. Bacteremia caused by Gordonia bronchialis in a patient with sequestrated lung. J. Clin. Microbiol. 42:2870-2871.

    Westphal, J. F., J. M. Brogard, F. Caro-Sampara, M. Adloff, J. F. Blickle, H. Monteil, and F. Jehl. 1997. Assessment of biliary excretion of piperacillin-tazobactam in humans. Antimicrob. Agents Chemother 41:1636-1640.

    Woo, P. C., K. H. Ng, S. K. Lau, K. T. Yip, A. M. Fung, K. W. Leung, D. M. Tam, T. L. Que, and K. Y. Yuen. 2003. Usefulness of the MicroSeq 500 16S ribosomal DNA-based bacterial identification system for identification of clinically significant bacterial isolates with ambiguous biochemical profiles. J. Clin. Microbiol. 41:1996-2001.

    Zardawi, I. M., F. Jones, D. A. Clark, and J. Holland. 2004. Gordonia terrae-induced suppurative granulomatous mastitis following nipple piercing. Pathology 36:275-278.(E. Gil-Sande, M. Brun-Ote)