Kathryn Bernard

The Genus Corynebacterium and Other Medically Relevant Coryneform-Like Bacteria

ABSTRACT Catalase-positive Gram-positive bacilli, commonly called “diphtheroids” or “coryneform” bacteria were historically nearly always dismissed as contaminants when recovered from patients, but increasingly have been implicated as the cause of significant infections. These taxa have been underreported, and the taxa were taxonomically confusing. The mechanisms of pathogenesis, especially for newly described taxa, were rarely studied. Antibiotic susceptibility data were relatively scant. In this minireview, clinical relevance, phenotypic and genetic identification methods, matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) evaluations, and antimicrobial susceptibility testing involving species in the genus Corynebacterium and other medically relevant Gram-positive rods, collectively called coryneforms, are described.

Characteristics of Rare or Recently Described Corynebacterium Species Recovered from Human Clinical Material in Canada

ABSTRACT Nineteen new Corynebacterium species or taxa described since 1995 have been associated with human disease. We report the characteristics of 72 strains identified as or most closely resembling 14 of these newer, medically relevant Corynebacterium species or taxa, as well as describe in brief an isolate of Corynebacterium bovis, a rare pathogen for humans. The bacteria studied in this report were nearly all derived from human clinical specimens and were identified by a polyphasic approach. Most were characterized by nearly full 16S rRNA gene sequence analysis. Some isolates were recovered from previously unreported sources and exhibited unusual phenotypes or represented the first isolates found outside Europe. Products of fermentation, with emphasis on the presence or absence of propionic acid, were also studied in order to provide an additional characteristic with which to differentiate among phenotypically similar species.

Multilocus Sequence Typing Identifies Evidence for Recombination and Two Distinct Lineages of Corynebacterium diphtheriae

ABSTRACT We describe the development of a multilocus sequence typing (MLST) scheme for Corynebacterium diphtheriae, the causative agent of the potentially fatal upper respiratory disease diphtheria. Global changes in diphtheria epidemiology are highlighted by the recent epidemic in the former Soviet Union (FSU) and also by the emergence of nontoxigenic strains causing atypical disease. Although numerous techniques have been developed to characterize C. diphtheriae, their use is hindered by limited portability and, in some instances, poor reproducibility. One hundred fifty isolates from 18 countries and encompassing a period of 50 years were analyzed by multilocus sequence typing (MLST). Strain discrimination was in accordance with previous ribotyping data, and clonal complexes associated with disease outbreaks were clearly identified by MLST. The data produced are portable, reproducible, and unambiguous. The MLST scheme described provides a valuable tool for monitoring and characterizing endemic and epidemic C. diphtheriae strains. Furthermore, multilocus sequence analysis of the nucleotide data reveals two distinct lineages within the population of C. diphtheriae examined, one of which is composed exclusively of biotype belfanti isolates and the other of multiple biotypes.

Molecular Methods and Platforms for Infectious Diseases Testing: A Review of FDA-Approved and Cleared Assays

The superior sensitivity and specificity associated with the use of molecular assays has greatly improved the field of infectious disease diagnostics by providing clinicians with results that are both accurate and rapidly obtained. Herein, we review molecularly based infectious disease diagnostic tests that are Food and Drug Administration approved or cleared and commercially available in the United States as of December 31, 2010. We describe specific assays and their performance, as stated in the Food and Drug Administrations Summary of Safety and Effectiveness Data or the Office of In Vitro Diagnostic Device Evaluation and Safetys decision summaries, product inserts, or peer-reviewed literature. We summarize indications for testing, limitations, and challenges related to implementation in a clinical laboratory setting for a wide variety of common pathogens. The information presented in this review will be particularly useful for laboratories that plan to implement or expand their molecular offerings in the near term.

Legionella pneumophila monoclonal antibody subgroups and DNA sequence types isolated in Canada between 1981 and 2009: Laboratory Component of National Surveillance.

Legionella pneumophila (Lp) is a significant cause of nosocomial, community-acquired, and travel-associated pneumonia in industrialized regions. Legionellosis has been a nationally notifiable disease in Canada since 1986, with an average of 75 cases reported annually; however, only the most severe, and often fatal, cases are reported or investigated. Here, epidemiological relationships, types, and distribution of Lp referrals to the Canadian national reference center were studied. Lp strains from different years, sources, and geographic locations were subtyped using a sequence-based typing (SBT) scheme and by the ‘Joly’ and/or ‘Dresden’ monoclonal antibody panels. Included were 128 epidemiologically unrelated clinical and 86 unrelated environmental strains. Sixty-four (index of diversity [IOD] = 0.964) and 45 (IOD = 0.888) sequence types (STs) were observed among clinical and environmental sources, respectively. Serogroup (sg) 1 was represented by 60.2% (77/128) and 52.3% (45/86) of clinical and environmental strains, respectively, and 63.6% (49/77) and 15.6% (7/45) of those were mAb2-positive, respectively. Serogroup 1, ST1 accounted for 14.1% (18/128) and 30.2% (26/86) of unrelated clinical and environmental isolates, respectively. This database will serve as a basis for Canadian epidemiological surveillance efforts and is linked to global surveillance initiatives curated by the European Working Group for Legionella Infections (EWGLI) network.

Human Clinical Isolates of Corynebacterium diphtheriae and Corynebacterium ulcerans Collected in Canada from 1999 to 2003 but Not Fitting Reporting Criteria for Cases of Diphtheria

ABSTRACT A 5-year collection of Corynebacterium diphtheriae and Corynebacterium ulcerans human clinical isolates yielded nine isolates from blood cultures of patients with invasive infections, stressing the importance of C. diphtheriae as a serious blood-borne pathogen. Seven percent of C. diphtheriae and 100% of C. ulcerans isolates produced diphtheria toxin, demonstrating that toxigenic corynebacteria continue to circulate.

Novel Corynebacterium diphtheriae in domestic cats.

Novel nontoxigenic Corynebacterium diphtheriae was isolated from a domestic cat with severe otitis. Contact investigation and carrier study of human and animal contacts yielded 3 additional, identical isolates from cats, although no evidence of zoonotic transmission was identified. Molecular methods distinguished the feline isolates from known C. diphtheriae.

Paracoccus yeeii sp. nov. (Formerly CDC Group EO-2), a Novel Bacterial Species Associated with Human Infection

ABSTRACT CDC eugonic oxidizer group 2 (EO-2) is a group of unclassified gram-negative bacterial strains isolated from various human sources. As determined by biochemical tests and analyses of fatty acid compositions, these organisms form a homogeneous group that appears to be distinct from but related to other Paracoccus species. Molecular studies were performed on a set of 13 EO-2 strains from various clinical sources and geographic locations in the United States and Canada to determine their relationship to the Paracoccus genus. Control strains were Paracoccus denitrificans ATCC 17741T, P. versutus ATCC 25364T, P. aminophilus ATCC 49673T, P. solventivorans ATCC 700252T, and Psychrobacter immobilis ATCC 43116T, which are phenotypically similar to EO-2. Nearly complete (1,500-base) 16S rRNA gene sequencing of eight EO-2 strains showed a high level of sequence similarity (>99.3%) within the group, and a BLAST search of GenBank placed the EO-2 cluster in close proximity to Paracoccus species (95 to 97% similarity). DNA-DNA hybridization studies of 13 of the EO-2 strains showed all to be related at the species level, with >70% relatedness under stringent conditions and a divergence within the group of less than 2%. None of the Paracoccus control strains hybridized at >54% with any of the EO-2 strains. These results indicate that EO-2 represents a new Paracoccus species, the first isolated from human clinical specimens. A new species, Paracoccus yeeii, is proposed for the EO-2 strains. The type strain of P. yeeii is CDCG1212 (ATCC BAA-599 and CCUG 46822), isolated in Pennsylvania from dialysate of a 77-year-old male with peritonitis.

Cutaneous Diphtheria in the Urban Poor Population of Vancouver, British Columbia, Canada: a 10-Year Review

ABSTRACT Between 1998 and 2007, records from 33 patients with cutaneous diphtheria from Vancouvers inner city were reviewed. Cases were associated with injection drug use and poverty. Coinfections with Staphylococcus aureus, Streptococcus pyogenes, and Arcanobacterium haemolyticum occurred. Corynebacterium diphtheriae is endemic in Vancouvers urban core, with strains of multilocus sequence type (MLST) 76 predominating.

Assignment of Brevibacterium stationis (ZoBell and Upham 1944) Breed 1953 to the genus Corynebacterium, as Corynebacterium stationis comb. nov., and emended description of the genus Corynebacterium to include isolates that can alkalinize citrate.

Brevibacterium stationis ATCC 14403(T), Corynebacterium ammoniagenes ATCC 6872 and two clinical isolates were found to form a single taxon group consistent with the genus Corynebacterium, designated here as Corynebacterium stationis comb. nov. The type strain of Corynebacterium stationis is ATCC 14403(T) =CCUG 43497( T) =CIP 104228(T) =DSM 20302(T) =NBRC 12144(T) =JCM 11611(T) =VKM B-1228(T). These strains can utilize citrate; therefore, inclusion of C. stationis requires that the description of the genus Corynebacterium be amended to include citrate-positive strains.