Apr 12, 1996 - resces red under UV light and reduces nitrate. When isolated ... A bone scan gave negative results, and a gallium scan showed uptake in the ...
JOURNAL OF CLINICAL MICROBIOLOGY, Dec. 1996, p. 3235–3236 0095-1137/96/$04.0010 Copyright q 1996, American Society for Microbiology
Vol. 34, No. 12
Veillonella parvula Bacteremia without an Underlying Source RANDALL G. FISHER*
AND
MARK R. DENISON
Department of Pediatric Infectious Diseases, Vanderbilt University Medical Center, Nashville, Tennessee Received 12 February 1996/Returned for modification 12 April 1996/Accepted 11 September 1996
Veillonella parvula is an anaerobic gram-negative coccus that is part of the normal human flora. It has rarely been identified as a pathogen in humans, and the most frequently reported infection caused by V. parvula is osteomyelitis. We report a case of bacteremia unrelated to a central venous catheter and without an underlying source of infection.
Veillonella parvula is a small, nonfermentative anaerobic gram-negative coccus that is part of the normal flora of the mouth, gastrointestinal tract, and vagina in humans. It fluoresces red under UV light and reduces nitrate. When isolated from clinical specimens, it is often regarded as a contaminant or a commensal. However, it has been isolated in pure culture from various sites and implicated as a pathogen in the sinuses, lungs, liver, central nervous system, heart, and bone. Bacteremia in the absence of an underlying source, however, is extremely rare; to our knowledge, there is only one prior case described in the literature (6). We report a case of V. parvula bacteremia. The patient was a 5-year-old boy with recurrent stage IV neuroblastoma who presented to the hematology-oncology clinic at Vanderbilt University Medical Center with a 5-day history of fever to 1028F (38.98C) and intermittent leg pain. On the day of his clinic visit, his temperature was 1048F (408C) and a blood specimen was obtained from a peripheral site and cultured. He had been off chemotherapy for 10 days. His leukocyte count at presentation was 2,500/mm3, with 57% segmented neutrophils. Three days earlier, however, his leukocyte count had been 1,100/mm3, with 35% segmented cells, yielding an absolute neutrophil count of 374. The blood culture, which was inoculated into a Peds plus/F bottle (Becton-Dickinson, Sparks, Md.) and processed by a Bactec 9240 nonradiometric system (BD), grew gram-negative cocci within 18 h, and the boy was admitted to the hospital and treated with vancomycin and ceftazidime. Repeat cultures were performed with blood drawn from both ports of his Hickman catheter at the time of admission. Physical examination revealed a patient who was active and alert, with an oral temperature of 101.38F (38.58C) and mild tachycardia. The findings in the remainder of the physical examination were normal, except for slight tenderness in the right upper quadrant of the patient’s abdomen. Following admission, the patient was afebrile until day 3 of hospitalization, when his temperature rose to 101.98F (38.88C). The original peripheral blood culture, which had been subcultured on Trypticase soy agar with sheep blood (BBL Microbiology Systems, Cockeysville, Md) and incubated at 358C in 7% CO2, and in an anaerobic GasPak jar (BBL), grew gram-negative cocci only in the anaerobic state. Blood was drawn from the patient’s Hickman catheter and from a peripheral site and cultured. The next morning, the new peripheral-site culture was also growing gram-negative cocci in pairs and short chains.
Antimicrobial therapy was changed to ceftriaxone and clindamycin. A careful physical examination showed the patient to have good dentition, without obvious carious lesions, mucositis, or gingivitis. No bony tenderness or joint swelling was noted. The original isolate was identified as a Veillonella species by the rapID ANA II System (Innovative Diagnostic Systems, Norcross, Ga.). A source for the bacteremia was sought. A bone scan gave negative results, and a gallium scan showed uptake in the superior mediastinum and lower posterior thorax that was confirmed by a CT scan to be due to tumor. A bone marrow biopsy showed persistent involvement by a tumor but was otherwise unremarkable. Bone marrow culture and sinus X rays gave negative results. The isolate was sent to the state laboratory for identification to species level, and it was positively identified as V. parvula on the basis of its biochemical profile. It grew well in both thioglycolate and chopped-meat carbohydrate-enriched thioglycolate broth, but not on thioglycolate gel; it was asacchrolytic; it was indole and bile esculin negative; and it reduced nitrate. Gas-liquid chromatography showed peaks at acetic and propionic acids. These reactions differentiated this organism from Acidaminococcus species and Megasphaera species, both of which are nitrate negative and have gas-liquid chromatographic peaks at butyric acid. Antimicrobial susceptibility testing was not performed. The patient became afebrile on therapy with ceftriaxone and clindamycin, and all subsequent blood cultures were negative. Isolation of a clinically relevant anaerobic gram-negative coccus is rare. V. parvula is the only one reported to cause infection in humans. Additionally, most cases of V. parvula infection are localized to one anatomic site. Bacteremia has been reported, but it is almost always in association with an underlying infection such as osteomyelitis (1, 2, 14). V. parvula bacteremia in the absence of an underlying site has been described once, in a 48-year-old man with posthepatitic cirrhosis (6). The authors speculated that an emergency central line may have been the source of his infection. Interestingly, although our patient had an indwelling Hickman catheter, only blood drawn from peripheral sites yielded positive culture results. There is also a report of a 71-year-old institutionalized man who was infected with V. parvula as part of a polymicrobial bacteremia (17). The literature describing anaerobic bacteremia in neonates contains references to three babies with blood cultures positive for V. parvula (5, 15). No further clinical detail of the cases is available, although in a review paper Brook states that all three patients had concomitant pneumonia (3). Anaerobic bacteremia, once considered fairly commonplace (in one study, anaerobes were identified in 49% of positive
* Corresponding author. Mailing address: Pediatric Infectious Diseases, D-7235 Medical Center North, Vanderbilt University Medical Center, Nashville, TN 37235. Phone: (615) 322-2250. Fax: (615) 3439723. 3235
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blood cultures over a 2-year period [11]), has decreased in frequency over the past 19 years (7). The reasons for the decline in the incidence of anaerobic bacteremia are not clear. Even when anaerobic bacteria were being isolated with high frequency, however, the isolation of V. parvula was not common. It is noteworthy that Martin’s study of 10,998 anaerobic isolates did not include a single case (11). Veillonella species have been reported as a cause of endocarditis (10), obstructive pneumonitis (9), lung abscess (12), chronic sinusitis (16), chronic tonsillitis (4), liver abscess (8), and even meningitis, in a child who injured her eyelid with a toothbrush (13). The most frequently reported infection with V. parvula is osteomyelitis, of which five reports exist. In only one case, however, was V. parvula the only organism identified (14). As is the case with many localized anaerobic infections, V. parvula is usually isolated as part of a polymicrobial process. This, combined with the fact that V. parvula is a normal inhabitant of the mouth, gastrointestinal tract, and vagina, has made elucidation of its pathogenetic role difficult. The case we describe, in which the organism was isolated twice in pure culture from a patient with symptoms compatible with bacteremia, illustrates that V. parvula cannot always be considered a commensal and that it should be eradicated in cases where it is likely to be a true pathogen. In patients with underlying immune deficiencies or exogenous immune suppression, V. parvula should be considered a pathogen. The finding of anaerobic gram-negative cocci on blood culture should prompt alternatives to standard fever and neutropenia antimicrobial regimens, especially given that V. parvula is vancomycin resistant. Although our patient had no identifiable underlying source of infection, one should be sought. V. parvula infection typically responds well to therapy with a penicillin. Other antimicrobial agents to which the organism is usually susceptible in vitro include cephalosporins, clindamycin, metronidazole, and chloramphenicol, although large susceptibility trials using clinical isolates have not been performed. This case also illustrates that in vitro susceptibility patterns do not always correlate with clinical cure.
J. CLIN. MICROBIOL. We thank Rosemary Verrall for reviewing the manuscript and making helpful suggestions. REFERENCES 1. Barnhart, R. A., M. R. Weitekamp, and R. C. Aber. 1983. Osteomyelitis caused by Veillonella. Am. J. Med. 74:902–904. 2. Borchardt, K. A., M. Baker, and R. Gelber. 1977. Veillonella parvula septicemia and osteomyelitis. Ann. Intern. Med. 86:63–64. 3. Brook, I. 1990. Bacteremia due to anaerobic bacteria in newborns. J. Perinatol. 10:351–355. 4. Chaturved, V. N., A. Methwani, P. Chaturved, and P. Narang. 1989. Bacterial flora in chronic tonsillitis. Indian Pediatr. 26:52–56. 5. Chow, A. W., R. D. Leake, T. Yamauchi, B. F. Anthony, and L. B. Guze. 1974. The significance of anaerobes in neonatal bacteremia: analysis of 23 cases and review of the literature. Pediatrics 54:736–745. 6. Gessoni, G., N. Saccheto, S. Gelmi, et al. 1989. Veillonellae: personal observation of a fatal bacteremia. Boll. Ist. Sieroter. Milan 68:193–196. 7. Gransden, W. R., S. J. Eykyn, and I. Phillips. 1991. Anaerobic bacteremia: declining rate over a 15-year period. Rev. Infect. Dis. 13:1255–1256. 8. Lambe, D. W., and V. E. DelBeve. The incidence and clinical significance of anaerobic cocci in certain infections. Presented at the 72nd Annual Meeting of the American Society for Microbiology, Philadelphia, 23 to 28 April 1972. 9. Liaw, Y. S., P. C. Yang, Z. G. Wu, et al. 1994. The bacteriology of obstructive pneumonitis. A prospective study using ultrasound-guided transthoracic needle aspiration. Am. J. Resp Crit. Care Med. 149:1648–1653. 10. Loughrey, A. C., and E. W. Chew. 1990. Endocarditis caused by Veillonella dispar. J. Infect. 21:319–320. 11. Martin, W. 1974. Isolation and identification of anaerobic bacteria in the clinical laboratory. A two-year experience. Mayo Clin. Proc. 49:300–308. 12. Mori, T., T. Ebe, M. Takahashi, H. Isonuma, H. Ikemoto, and T. Oguri. 1993. Lung abscess: analysis of 66 cases from 1979 to 1991. Intern. Med. 32:278–284. 13. Nukina, S., A. Hibi, and K. Mishida. 1989. Bacterial meningitis caused by Veillonella parvula. Acta Paediatr. Jpn. 31:609–614. 14. Singh, N., and V. L. Yu. 1992. Osteomyelitis due to Veillonella parvula. Case report and review. Clin. Infect. Dis. 14:361–363. 15. Spector, S. A., W. Ticknor, and M. Grossman. 1981. Study of the usefulness of clinical and hematologic findings in the diagnosis of neonatal bacterial infections. Clin. Pediatr. 20:385–392. 16. Su, W. Y., C. Liu, S. Y. Hung, and W. F. Tsai. 1983. Bacteriologic study in chronic maxillary sinusitis. Laryngoscope 93:931–934. 17. Wilson, W. R., W. J. Martin, C. J. Wilkowske, and J. A. Washington II. 1972. Anaerobic bacteremia. Mayo Clin. Proc. 47:639–646.
