Novel Fastidious, Partially Acid-Fast, Anaerobic Gram-Positive Bacillus Associated with Abscess Formation and Recovered from Multiple Medical Centers

Abstract

We report a novel anaerobe causing abscess in four patients at three hospitals. In the clinical specimen, bacilli were branching, Gram positive, and acid fast. The organism grew slowly and was not identified by 16S rRNA sequencing. Our findings support the description of a new genus and species of the suborder Corynebacterineae. CASE REPORTSC ase 1. A 65-year-old male with metastatic prostate cancer diagnosed in Cleveland, OH, in March 2009 presented 1 June 2011 with an enlarging mass adjacent to a surgical incision at T3-8 from previous spinal stabilization at the time of diagnosis. Medications included prednisone (5 mg daily), docetaxel, zoledronic acid, and leuprolide. There was no significant travel history, exposure to animals, or sick contacts. He denied trauma to the upper back and had a sedentary life. A physical exam revealed a weight of 130 kg, blood pressure of 106/78, pulse of 160/min (atrial fibrillation), temperature of 38.6°C, and respiratory rate of 22/min. He was unaware of his fever. The mass was minimally warm to the touch, mildly erythematous, fluctuant, nondraining, and nonpainful. The white blood cell (WBC) count was 12,370/l with 77% neutrophils.The magnetic resonance imaging (MRI) and computed tomography (CT) scan were consistent with thoracic fluid collection and abscess. Surgical incision and drainage produced a large amount of purulent, nonodorous fluid. Pedicle screws placed previously were solidly in position, and there was no evidence of bony destruction. Partial hardware removal and debridement of necrotic tissue were performed. A swab of the subfascial tissue, fluid, and hardware were submitted for culture. A beaded Gram-positive, branching bacillus and inflammatory cells were present on Gram stains of all material submitted. Modified Kinyoun stain was positive. (Fig. 1a and b).Vancomycin started prior to surgery was switched to ampicillin-sulbactam but changed to meropenem due to suspicion of Nocardia. Blood cultures produced no growth. The white blood cell count normalized, and he was afebrile by postoperative day 2. His surgical site healed well, and he was discharged postoperative day 7 on meropenem. After 4 weeks, home antibiotic therapy was switched to sulfamethoxazole-trimethoprim (SXT) at 800 to 160 mg with two tablets 3 times per day (TID). Docetaxel chemotherapy was resumed.Anaerobic cultures of the fluid and hardware grew after 13 days of incubation. Cultures performed from swabs of tissue did not grow, nor was growth obtained from any specimen submitted for culture for mycobacteria, fungi, and aerobic bacteria. By partial 16S rRNA sequencing, the organism was Ͻ95% identical to Dietzia, Tsukamurella, and Corynebacterium spp. The 16S rRNA sequence (1,445 bp) was later submitted to GenBank. With these results, therapy was changed to amoxicillin-clavulanate (1,000/ 62.5 mg twice daily).Five weeks postoperatively, a scant amount of clear yellow nonodorous fluid was noted draining from a pinhole-sized opening of a 3-cm fluctuant, nonerythematous collection at the surgical si...

Lawsonella clevelandensis gen. nov., sp. nov., a new member of the suborder Corynebacterineae isolated from human abscesses

“…These results are consistent with those reported previously for NML 120705 (Harrington et al, 2013). Cellular fatty acid analysis was repeated three times under varied conditions to gain a more complete understanding of the growth characteristics of this new taxon.…”

“…Strains have been isolated only from human sources: a spinal abscess, two breast abscesses, a liver abscess and a peritoneal abscess (unpublished), all in different geographic locations in the USA and Canada. The cases shared the following common characteristics: isolation from abscess material; three individuals were immunocompromised with extensive medical histories and all but one had been diagnosed with diabetes mellitus type II (Harrington et al, 2013;unpublished). Due to the fastidious nature of this organism and the lengthy incubation time required, it could be an often overlooked opportunistic pathogen originating as part of the normal human microbiome.…”

“…Based on the results of this polyphasic study, we conclude that these strains represent a novel genus and species within the suborder Corynebacterineae for which we propose the name Lawsonella clevelandensis gen. nov., sp. nov., with the type strain X1036 Previously, Harrington et al (2013) published a report of four cases of human abscess from which an unidentified fastidious, Gram-stain-positive, partially acid-fast bacillus was detected. Based on nearly full-length 16S rRNA gene sequence similarity values (100 %) and the distinctive morphological and phenotypic characteristics shared by these strains, they were believed to belong to the same genus and species.…”

“…Preliminary descriptions and the details of isolation methods from clinical samples for strain NML 120705 (isolated in Winnipeg, Manitoba, Canada) and strain X1036 T (isolated in Cleveland, OH, USA) were described previously (Harrington et al, 2013). For characterization studies, X1036…”

Can anaerobes be acid fast? A novel, clinically relevant acid fast anaerobe

“…Since all efforts to identify the organism in the microbiology laboratory as well as at a local reference laboratory were unsuccessful, the isolate was sent to the University of Washington for sequencing. No matching sequence with species level identification was found in the database; however the sequence did match that of a novel organism that had been described in four different patients before (Harrington et al , 2013). The isolate was then sent to the Centers for Disease Control and Prevention (CDC) for characterization and further study.…”