Peritonitis associated with a CDC group EO-3 organism.

A 63-year-old female with chronic renal failure on continuous ambulatory peritoneal dialysis developed chronic peritonitis. A CDC group EO-3 organism was isolated from the peritoneal dialysis fluid on five occasions over a period of 4 months. This is the first reported isolation of this organism in which it is associated with a patient on continuous ambulatory peritoneal dialysis.     

Primary identification of Microbacterium spp. encountered in clinical specimens as CDC coryneform group A-4 and A-5 bacteria.

Over nearly two decades, 13 yellow- or orange-pigmented, fermentative gram-positive rods belonging to the genus Microbacterium were encountered in clinical specimens. All 13 strains, 10 of which came from blood cultures, were initially identified as CDC coryneform group A-4 and A-5 bacteria according to the scheme of Hollis and Weaver for the identification of gram-positive rods. The clinical isolates were compared with the type strains of the six species constituting the genus Microbacterium as well as with three Microbacterium strains isolated from hospital environments. By biochemical methods only 5 of 13 clinical isolates could be identified to species level. Peptidoglycan analysis proved to be a valuable tool for differentiation between Microbacterium spp. and related genera, whereas cellular fatty acid analysis did not allow species identification within the genus Microbacterium. The 22 Microbacterium strains studied were, in general, susceptible to antimicrobial agents used in the treatment of infections caused by gram-positive rods. This report is the first one concerning the isolation of Microbacterium strains from clinical specimens. The sources as well as the mode of transmission remain to be established.     

Neisseria elongata subsp. nitroreducens subsp. nov., formerly CDC group M-6, a gram-negative bacterium associated with endocarditis.

CDC group M-6 is the vernacular name given to a gram-negative, oxidase-positive, aerobic, nonmotile, rod-shaped bacterium. This organism is biochemically similar to Kingella denitrificans and displays a cellular fatty acid profile consistent with CDC groups M-5 and EF-4 and with Neisseria elongata. Of the 95 M-6 strains referred to the Centers for Disease Control (CDC) for identification, 32 (64%) of the first 50 were from the throat or sputum and only 3 (6%) were from blood; only 5 (11%) of the next 45 isolates were from the upper respiratory tract and 23 (51%) were from blood, with many of these (15 or 65%) being associated with endocarditis. The major characteristics of CDC group M-6 include reduction of nitrate and nitrite with no gas formation; positive reaction for oxidase; negative reactions for catalase, urease, indole, and motility; and no acid production from carbohydrates. Guanine-plus-cytosine content determined spectrophotometrically by thermal denaturation was 55 to 58 mol % for six M-6 strains tested: 56 mol % for the N. elongata subsp. elongata type strain and for the N. elongata subsp. glycolytica type strain. By the hydroxyapatite method, DNAs from 24 M-6 strains showed an average of 78% relatedness to M-6 reference strain B1019 in reactions at 60 degrees C and 73% relatedness in reactions at 75 degrees C. M-6 strain B1019 was 79% related to the N. elongata type strain at 60 degrees C and 71% related at 75 degrees C; it was 75% related to the type strain N. elongata subsp. glycolytica at 60 degrees C and was 66% related at 75 degrees C. DNAs from CDC group EF-4, K. denitrificans, and CDC group M-5 were all less than 14% related to CDC group M-6 at 75 degrees C. The DNA relatedness data showed conclusively that all the M-6 strains belong in the species N. elongata. M-6 is different from N. elongata subsp. elongata in that M-6 reduces nitrate and sometimes weakly acidifies D-glucose, and it is different from N. elongata subsp. glycolytica in that it reduces nitrate and is negative for glucose and catalase. Because of the apparent clinical significance of M-6 compared with the clinical significance of N. elongata subsp. elongata and N. elongata subsp. glycolytica and the ease in distinguishing it biochemically, we propose M-6 as a third subspecies of N.elongata, N. elongata subsp. nitroreducens subsp. nov.     

Cancer risk associated with receipt of vaccines contaminated with simian virus 40: epidemiologic research

Simian virus (SV)40 was an accidental contaminant of poliovirus vaccines used widely in the USA and other countries in 1955-1962. Exposure to SV40 via contaminated vaccines has led to concern as SV40 causes cancer in laboratory animals. In addition, some laboratories, although not all, have detected SV40 DNA in human tumors including mesothelioma, certain brain tumors, osteosarcoma and non-Hodgkin's lymphoma. This article reviews the data regarding contamination of poliovirus vaccines with SV40 and summarizes the results from epidemiologic studies of vaccine recipients. Long-term follow-up studies have not revealed recipients of SV40-contaminated poliovirus vaccines to be at an increased risk for cancer. Thus, these studies are somewhat reassuring and indicate that either SV40 does not readily infect humans or, following infection, does not cause cancer. Recognizing that the history of SV40 contamination of vaccines highlights an inherent risk of contamination of vaccines with adventitious agents, the Institute of Medicine recently called for the development of a comprehensive US plan to prevent vaccine contamination and respond to potential contamination events when they arise.     

Bacteremia and urinary tract infection associated with CDC group Vd biovar 2.

A case of urinary tract infection and bacteremia caused by CDC group Vd biovar 2 in a 23-year-old woman with Hodgkin's disease is described. This is the first report of CDC group Vd biovar 2 isolated from a clinical specimen and considered as a pathogen. Detailed antimicrobial susceptibility data are presented.     

Oerskovia xanthineolytica implicated in peritonitis associated with peritoneal dialysis: case report and review of Oerskovia infections in humans.

Oerskovia species are nocardialike bacteria that have been implicated as pathogens only rarely. These organisms are branched, gram-positive bacilli that are oxidase negative, catalase positive, and non-acid fast. Unlike Nocardia species, these organisms are motile, do not produce aerial mycelia, and possess a cell wall with large amounts of galactose. Colonies are bright yellow and produce branched vegetative hyphae on nutrient agar. A 70-year-old patient undergoing chronic ambulatory peritoneal dialysis for end-stage renal dysfunction developed recurrent peritonitis. Five peritoneal fluid cultures and one catheter specimen obtained over a period of two weeks yielded a gram-positive bacillus; Oerskovia xanthineolytica was isolated from all six cultures. Prolonged systemic therapy with gentamicin and vancomycin was unsuccessful in curing the peritonitis, but the infection resolved following removal of the peritoneal catheter. This is the first reported case of peritonitis associated with this microorganism. A review of previously described Oerskovia infections, most of which were associated with foreign bodies, showed that removal of infected foci was usually necessary for cure.     

Molecular epidemiologic evaluation of transmissibility and virulence of Mycobacterium tuberculosis.

Discovery of genotypic markers associated with increased transmissibility in Mycobacterium tuberculosis would represent an important step in advancing mycobacterial virulence studies. M. tuberculosis strains may be classified into one of three genotypes on the basis of the presence of specific nucleotide substitutions in codon 463 of the katG gene (katG-463) and codon 95 of the gyrA gene (gyrA-95). It has previously been reported that two of these three genotypes are associated with increased IS6110-based clustering, a potential proxy of virulence. We designed a case-control analysis of U.S.-born patients with tuberculosis in San Francisco, Calif., between 1991 and 1997 to investigate associations between katG-463 and gyrA-95 genotypes and epidemiologically determined measures of strain-specific infectivity and pathogenicity and IS6110-based clustering status. We used a new class of molecular probes called molecular beacons to genotype the isolates rapidly. Infectivity was defined as the propensity of isolates to cause tuberculin skin test conversions among named contacts, and pathogenicity was defined as their propensity to cause active disease among named contacts. The molecular beacon assay was a simple and reproducible method for the detection of known single nucleotide polymorphisms in large numbers of clinical M. tuberculosis isolates. The results showed that no genotype of the katG-463- and gyrA-95-based classification system was associated with increased infectivity and pathogenicity or with increased IS6110-based clustering in San Francisco during the study period. We speculate that molecular epidemiologic studies investigating clinically relevant outcomes may contribute to the knowledge of the significance of laboratory-derived virulence factors in the propagation of tuberculosis in human communities.     

Fatal case of toxic shock-like syndrome due to group C streptococcus associated with superantigen exotoxin

Group C streptococci have been reported to cause invasive disease similar to that classically associated with group A streptococcus (GAS). We describe a fatal case of toxic shock-like syndrome due to Streptococcus equi subsp. zooepidemicus. The causative organism did not possess any known GAS superantigen exotoxin genes but did show evidence of superantigen production.     

Characteristics of CDC group 3 and group 5 coryneform bacteria isolated from clinical specimens and assignment to the genus Dermabacter.

Over a 1-year period, 11 isolates (including 5 from blood cultures) of the recently described CDC group 3 and group 5 coryneform bacteria were derived from clinical specimens and compared with reference strains. Biochemical characteristics indicated a very close relationship between CDC group 3 and group 5 coryneform bacteria. The ability of CDC group 3 and the inability of CDC group 5 coryneform bacteria to ferment xylose were the only reactions that were different for the two taxa. Chemotaxonomic features of the two groups included the presence of meso-diaminopimelic acid, a lack of mycolic acids, and the presence of predominantly branched cellular fatty acids, a combination found among gram-positive rods only in Brevibacterium spp., Brachybacterium faecium, and Dermabacter hominis. 16S rRNA gene sequence analysis revealed that CDC group 3 and group 5 coryneform bacteria are members of the genus Dermabacter, which to date has been isolated exclusively from human skin.     

Chemical characterization of clinical isolates which are similar to CDC group DF-3 bacteria.

Six clinical isolates, taken from blood or wounds, that had biochemical characteristics most similar to Centers for Disease Control group DF-3 bacteria were examined for cellular fatty acid composition and isoprenoid quinone content to evaluate their chemical relatedness to known bacterial species and groups. The fatty acids were liberated from whole cells by base hydrolysis, methylated, and analyzed by capillary gas-liquid chromatography. The isoprenoid quinones were extracted from lyophilized whole cells and analyzed by reverse-phase high-performance liquid chromatography. All six strains, which were designated group DF-3-like, possessed a distinct fatty acid profile that was characterized by large amounts (greater than 20%) of 13-methyltetradecanoate (i-C15:0) and 12-methyltetradecanoate (a-C15:0), moderate amounts of saturated branched-chain 13-carbon acids (i-C13:0 and a-C13:0) and hexadecanoate (n-C16:0), and small to moderate amounts of both branched- and straight-chain hydroxy acids (i-3-OH-C15:0, 3-OH-C16:0, i-3-OH-C17:0, and 2-OH-C17:0). This fatty acid profile was unique compared with the profiles of group DF-3 and other bacteria we have previously tested and is useful for the rapid identification of group DF-3-like isolates. The isoprenoid quinone content of four group DF-3-like strains was similar, with ubiquinone-9 (Q-9) and Q-10 as their major quinones, while the other two group DF-3-like strains contained Q-7 as their major quinones, with smaller amounts of Q-8 and Q-9.     

Phenotypic and genetic characterization of clinical isolates of CDC coryneform group A-3: proposal of a new species of Cellulomonas, Cellulomonas denverensis sp. nov

CDC coryneform group A-3 bacteria are rare human pathogens. In this study, six group A-3 isolates (two from blood, one from cerebrospinal fluid, and one each from homograft valve, lip wound, and pilonidal cyst) were compared to the type strains of phenotypically related organisms, Cellulomonas fimi, Cellulomonas hominis, Oerskovia turbata, and Sanguibacter suarezii, and characterized by phenotypic, chemotaxonomic, and genotypic studies. DNA-DNA reassociation analysis identified two genomic groups, and phylogenetic analysis of the 16S rRNA gene sequence identified the taxonomic positions of these groups to genus level. Two groups were defined, and both were more closely related to Cellulomonas species: one group of three strains, for which we propose the new species Cellulomonas denverensis sp. nov., with the type strain W6929 (ATCC BAA-788(T) or DSM 15764(T)), was related to C. hominis ATCC 51964(T) (98.5% 16S rRNA gene sequence similarity), and the second group of three strains was related to C. hominis ATCC 51964(T) (99.8 to 99.9% 16S rRNA gene sequence similarity). The definition of this new Cellulomonas species and the confirmation of three strains as C. hominis serve to further clarify the complex taxonomy of CDC coryneform group A-3 bacteria and will assist in our understanding of the epidemiology and clinical significance of these microorganisms.     

Role of group C beta-hemolytic streptococci in pharyngitis: epidemiologic study of clinical features associated with isolation of group C streptococci.

All Lancefield group C beta-hemolytic streptococci isolated over 12 months from college students with clinical pharyngitis and age-matched healthy controls were identified. Clinical features of upper respiratory tract infection and pyogenic pharyngitis as well as colony counts were tabulated for each patient according to throat culture results. Of 1,480 patients, Lancefield group C Streptococcus equisimilis was isolated from 45 (3%) patients and Streptococcus anginosus ("Streptococcus milleri") was isolated from 164 (11.1%) patients. Patients from whom S. equisimilis was isolated had clinical features more suggestive of pyogenic infection than did patients from whom S. anginosus was isolated. Colony counts on primary throat culture plates from patients from whom S. equisimilis and Streptococcus pyogenes were isolated were higher than those from patients from whom S. anginosus was isolated. This study presents epidemiologic evidence supporting a role for S. equisimilis in causing pharyngeal infection and for S. anginosus as representing part of the normal oropharyngeal flora.     

Simplified serological diagnosis of endocarditis due to Coxiella burnetii and Bartonella

We tested a single-step serological assay against Coxiella burnetii and Bartonella species and found a sensitivity of 100%, and a positive predictive value of 98% for the diagnosis of blood culture-negative endocarditis (BCNE). This assay should be considered as a possible commercial test for the diagnosis of BCNE.     

Meningococcal meningitis associated with persistent hypocomplementaemia due to circulating C3 nephritic factor.

Two teenage patients who presented with meningococcal meningitis were found to have persistently low C3 levels even after recovery. This was accompanied by circulating C3 nephritic factor, which persisted for more than 12 months in each case. Neither patient had evidence of partial lipodystrophy or of glomerulonephritis initially, although one patient subsequently developed mesangioproliferative glomerulonephritis following a second admission with pneumococcal pneumonia. It is possible that the generation of the nephritic factor was initiated during the presenting illness.