Varibaculum cambriense infections in Hong Kong, China, 2006

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Bausch DG, Borchert M, Grein T, Roth C, Swanepoel R, Libande ML, et al. Risk factors for Marburg hemorrhagic fever, Democratic Republic of the Congo. Emerg Infect Dis. 2003;9:1531–7. 10. Borchert M, Mulangu S, Swanepoel R, Tshomba A, Afounde A, Kulidri A, et al. Pygmy populations seronegative for Marburg virus. Emerg Infect Dis. 2005;11:174–7. Address for correspondence: Eric M. Leroy, Centre International de Recherches Médicales de Franceville, BP 769, Franceville, Gabon; email: [email protected] Varibaculum cambriense Infections in Hong Kong, China, 2006 To the Editor: Varibaculum cam- briense is an anaerobic, gram-posi- tive, diphtheroid bacterium that was described by Hall et al. in 2003 (1). Biochemical testing, electrophoretic analysis of whole-cell proteins, and phylogenetic analysis of 16S rRNA gene sequences showed that V. cam- briense is related to but distinct from Actinomyces spp. and related taxa, including the genera Actinobaculum, Arcanobacterium, and Mobiluncus. Although its natural habitat re- mains unknown, V. cambriense has been isolated from intrauterine de- vices and human vagina and abscess specimens (2). Commercial systems, such as analytical profile index (API) Rapid ID 32 Strep and Coryne kits (bioMérieux, Marcy l’Etoile, France), used in differentiation of novel bacte - ria provide biochemical profiles useful for identification of V. cambriense (1). However, the absence of data on this organism in manufacturers’ databases has hampered recognition of V. cam- briense in routine clinical laboratories. We report 4 cases of V. cambriense in- fection and show that this bacterium is a potential pathogen in skin and soft tissue infections. In 2006, four isolates of gram- positive curved bacilli that grew on Columbia agar with 5% horse blood under anaerobic conditions were re- ferred by 2 regional hospitals in Hong Kong to our laboratory for identifica - tion. These isolates originated from the abscess specimens of 4 patients. Patient 1 was a 45-year-old wom- an with a right ovarian chocolate cyst and endometriosis who had undergone laparotomy, right salpingo-oophorec - tomy, and lysis of adhesions in 2001. Since then, she had a recurrent abscess over the umbilical scar that was treat - ed conservatively. Culture of pus from Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 15, No. 7, July 2009 1137 1These authors contributed equally to this article. All material published in Emerging Infectious Diseases is in the public domain and may be used and reprinted without special permission; proper citation, however, is required. LETTERS the umbilical scar grew an unidenti - fied gram-positive bacillus (M124). Histologic analysis of umbilical tissue showed acute suppurative inflamma - tory cells and microabscess formation. The patient refused follow-up and no antimicrobial drug treatment was given. Patient 2 was a 25-year-old man who had a history of excision of mul- tiple sebaceous cysts in the groin, and buttock pain and swelling for 4 days. He had no previous trauma and was afebrile. An abscess was incised and drained. Culture of tissue obtained grew an unidentified gram-positive ba- cillus (M397) and a Peptostreptococ- cus spp. The infection later subsided without antimicrobial drug treatment. Patient 3 was a 34-year-old man with a lump in the left groin that had been present for 1 year. He was hos- pitalized with erythema and increased swelling of the lesion. An abscess was diagnosed, incised, and drained. Gram staining of pus showed numerous leukocytes and gram-positive bacilli. Culture yielded an unidentified gram- positive bacillus (M380). He was treated with ampicillin and cloxacillin, and the wound healed. Patient 4 was a 55-year-old wom- an with an abscess on her back. She had a 3-year history of seronegative rheumatoid arthritis but was not re- ceiving immunosuppressant therapy. The abscess was drained, and gram staining of pus showed numerous leu- kocytes and gram-positive cocci and bacilli. Culture yielded Peptostrepto- coccus spp. and an unidentified gram- positive bacillus (M398). The abscess healed without antimicrobial drug treatment. The 4 unidentified gram-positive bacilli from these patients were ini- tially characterized by using the API Rapid ID 32 Strep and Coryne kits. Doubtful identifications at various confidence levels were obtained, in- cluding Corynebacterium diphtheriae var. mitis or var. belfanti, Gardner- ella vaginalis, Streptococcus mitis, S. oralis, Gemella morbillorum, and Aerococcus urinae. Sequencing of full length 16S rRNA genes suggested that the isolates were V. cambriense; Gen- Bank BLAST (http://blast.ncbi.nlm. nih.gov/Blast.cgi) results showed V. cambriense type strain CCUG 44998 T sequence as the best match (identities 98%–99%) (3). Biochemical reactions of the strains were similar to those of CCUG 44998 T (1). All 4 isolates grew poorly in air and 5% CO2, were catalase nega- tive, did not hydrolyse esculin or gela- tin, or reduce nitrates. The 4 isolates did not ferment most of the carbo- 1138 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 15, No. 7, July 2009 Table. Characteristics and test results for 4 isolates of unknown bacteria, Hong Kong, China, 2006* Isolate Characteristic Varibaculum cambriense type strain CCUG 44998 T M124 M397 M380 M398 Hospital B B A A Patient sex/age, y F/45 M/25 M/34 F/55 Date referred/isolated 2006 May 2006 Dec 2006 Dec 2006 Dec API test code Rapid ID32 Strep 00100010100 00102010100 02122001100 00002011100 Coryne 1010321 1410321 1010721 1010321 Acid production from Glucose + + + + + Lactose – – – – – Maltose V – (+) – (+) + + Melibiose – – – – – Pullulan – – – – – Raffinose – – – – – Ribose V + + + – (+) Sucrose V + + + + Trehalose V – – + – MBDG – – – – – Hydrolysis of hippurate V + + – + Production of Į-galactosidase – – – + – ȕ-galactosidase V – – (+) – – Į-glucosidase + – (+) – (+) – (+) – (+) Alkaline phosphatase – – – – – APPA V – + + + GenBank accession no.† FJ169866 FJ169867 FJ169868 FJ169869 Identity to type strain CCUG 44998 T , % 99 98 99 99 *API, analytical profile index; V, variable; MBDG, methyl-ȕ-D-glucopyranoside; APPA, alanyl-phenylalanyl-proline arylamidase. Test

were obtained by using the API Rapid ID32 Strep kit (bioMérieux, Marcy l’Etoile, France). Results in parentheses were obtained by using the API Coryne kit (bioMérieux). †For 16S rRNA gene sequence. LETTERS hydrates in the 2 API kits, except for ribose, maltose, glucose, and sucrose. Discrepancies in results between the 2 test kits were seen with ribose in 1 iso- late (M398) and maltose in 2 isolates (M124 and M397). One isolate (M380) did not hydrolyze hippurate but pro- duced acid from trehalose and xylose. This isolate was also α-galactosidase positive, a result different from that of the type strain. All 4 isolates were α-glucosidase positive and 3 were ala- nyl-phenyl-alanyl-proline arylamidase positive. Some of the biochemical re- actions for the 4 isolates, including all tests for delineating V. cambriense from other catalase-negative Actino- myces spp. (1), are summarized in the Table. We report the isolation of V. cam- briense from 4 patients with purulent skin and soft tissue infections. Our findings contribute to understanding of the clinical and pathogenic po- tential of this anaerobic bacterium. Gram-positive diphtheroid organisms from wound specimens are occasion - ally considered to be skin commensal organisms. Clinical microbiologists should be aware of this organism and the current inadequacy of commercial systems for its identification. We have shown that 16S rRNA gene sequenc- ing is a useful alternative to gas–liquid chromatographic analyses of cell wall fatty acids or metabolic products for identification of anaerobic gram-pos- itive bacilli. Yiu-Wai Chu, Chi-Ho Wong, Man-Yu Chu, Cara P.F. Cheung, Terence K.M. Cheung, Cindy Tse, Wei-Kwang Luk, and Janice Y.C. Lo Author affiliations: Centre for Health Pro- tection, Hong Kong, People’s Republic of China (Y .-W. Chu, C.-H. Wong, M.-Y . Chu, C.P .F . Cheung, T .K.M. Cheung, J.Y .C. Lo); Kwong Wah Hospital, Hong Kong (C. T se); and T seung Kwan O Hospital, Hong Kong (W.-K. Luk) DOI: 10.3201/eid1507.081291

1. Hall V , Collins MD, Lawson PA, Hutson RA, Falsen E, Inganas E, et al. Character- ization of some Actinomyces-like isolates from human clinical sources: description of Varibaculum cambriensis gen. nov., sp. nov. J Clin Microbiol. 2003;41:640–4. DOI: 10.1128/JCM.41.2.640-644.2003 2. Verhelst R. Characterization of the vaginal microflora [dissertation]. Ghent (the Neth- erlands): University of Ghent; 2006. 3. Edwards U, Rogall T, Blocker H, Emde M, Bottger EC. Isolation and direct com- plete nucleotide determination of entire genes. Characterization of a gene coding for 16S ribosomal RNA. Nucleic Acids Res. 1989;17:7843–53. DOI: 10.1093/ nar/17.19.7843 Address for correspondence: Yiu-Wai Chu, Public Health Laboratory Centre, 382 Nam Cheong St, Kowloon, Hong Kong Special Administrative Region, People’s Republic of China; email: [email protected] Outbreaks of Hemotrophic Mycoplasma Infections in China To the Editor: Infections caused by hemotrophic mycoplasmas (for - merly called eperythrozoonoses) in animals and humans have been emerg- ing in the People’s Republic of China in recent years. To date, 6 hemotrophic Mycoplasma spp. have been identified in rodents and mammals (1 ). M. suis from pigs, M. wenyonii from cattle, and M. ovis from sheep have been con- firmed; the human pathogen, which is most frequently observed in China, has not been genetically identified (2). However, the zoonotic potential of the bacteria is evident because the disease is more prevalent in farmers and veter- inary doctors, who have frequent close contact with domestic animals, than in other persons (2 ). Vertical trans- mission from mother to fetus has also been confirmed (2). In animals, espe- cially in piglets, the disease is charac- terized by febrile acute anemia, jaun- dice, and eventual death resulting from concurrent infection with other mi- crobes (3–6). Infected humans may be asymptomatic or have various clinical signs, including acute fever, anemia, and severe hemolytic jaundice, espe- cially in infected neonates. Pregnant women and newborns were reported to be more vulnerable to the disease than others and to show more severe clini- cal signs after infection (2). We conducted an epidemiologic investigation of hemotrophic myco- plasma infections in China by review- ing all reported cases and outbreaks for 1994–2007. Clinical cases for >6 animal species (including pigs, cows, goats, horses, foxes, chickens, and hu- mans) were reported during the period (Table). The number of reported cases varied from year to year. Human infec- tions were confirmed by clinical and laboratory methods (2). We reinvesti - gated blood samples of >600 pigs with previous diagnoses of mycoplasma in- fection accompanied by clinical signs of fever and jaundice. Slides were made and stained in Giemsa-staining solution. We used light microscopy to look for the presence of M. suis on the erythrocyte surface. We also used flu- orescence microscopy to look for the microbes by mixing a drop of infected blood with acridine orange solution (0.1 mg/mL). The microbes bound to red blood cells were examined with a confocal microscope. Positive cases were further confirmed by PCR us- ing primers of the small subunit RNA gene sequences. All samples were PCR positive, but PCR sensitivity is higher than sensitivity of acridine or - ange staining, which is higher than sensitivity of Geimsa staining. Hemotrophic mycoplasma infec- tion is still a neglected zoonotic disease, which poses a threat to public health and the animal industry, especially in China (2,7). The prevalence of the dis- Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 15, No. 7, July 2009 1139