Desulfovibrio desulfuricans bacteremia in an immunocompromised host with a liver graft and ulcerative colitis.

Desulfovibrio spp. are anaerobic, sulfate-reducing, nonfermenting, Gram-negative bacteria found in the digestive tract of humans. Identification of these species with conventional methods is difficult. The reported case of a Desulfovibrio desulfuricans bacteremia occurring in an immunocompromised host with ulcerative colitis confirms that this organism may be a possible opportunistic human pathogen.

Psychrobacter isolates of human origin, other than Psychrobacter phenylpyruvicus, are predominantly Psychrobacter faecalis and Psychrobacter pulmonis, with emended description of P. faecalis.

Human Psychrobacter isolates, other than Psychrobacter phenylpyruvicus, are predominantly designated Psychrobacter immobilis. Phenotypic and genotypic testing of Psychrobacter isolates that have been deposited in different culture collections as P. immobilis indicates that most of these human isolates belong to the species Psychrobacter faecalis and Psychrobacter pulmonis.

Isolates belonging to CDC group II-i belong predominantly to Sphingobacterium mizutaii Yabuuchi et al. 1983: emended descriptions of S. mizutaii and of the genus Sphingobacterium.

Two clinical strains, NF 296 and NF 931, present in our collection, were identified biochemically as members of CDC group II-i. Determination of the 16S rRNA gene sequence revealed highest similarity with strains of Sphingobacterium mizutaii. Because these strains produced indole, whereas S. mizutaii has been described as indole-negative, we also investigated the type strain and a reference strain of S. mizutaii, LMG 8340(T) (=CCUG 15907(T)) and LMG 8341 (=CCUG 15908), and found both strains also to be positive for indole production. These data warrant inclusion of some of the CDC group II-i strains into S. mizutaii and emended descriptions of Sphingobacterium mizutaii as indole-production-positive and of the genus Sphingobacterium as variable for indole production.

Outbreaks of keratoconjunctivitis in a camel herd caused by a specific biovar of Moraxella canis.

Two tributyrin hydrolysis-negative Moraxella isolates obtained in cases of keratoconjunctivitis in Camelus dromedarius in the Canary Islands showed highest degrees of 16S rRNA gene sequence similarity to Moraxella canis. A level of DNA relatedness to the M. canis type strain of 79% confirmed the identity of the isolates as a tributyrin hydrolysis-negative biovar of M. canis.

Species identification of corynebacteria by cellular fatty acid analysis.

We evaluated the usefulness of cellular fatty acid analysis for the identification of corynebacteria. Therefore, 219 well-characterized strains belonging to 21 Corynebacterium species were analyzed with the Sherlock System of MIDI (Newark, DE). Most Corynebacterium species have a qualitative different fatty acid profile. Corynebacterium coyleae (subgroup 1), Corynebacterium riegelii, Corynebacterium simulans, and Corynebacterium imitans differ only quantitatively. Corynebacterium afermentans afermentans and C. coyleae (subgroup 2) have both a similar qualitative and quantitative profile. The commercially available database (CLIN 40, MIDI) identified only one third of the 219 strains correctly at the species level. We created a new database with these 219 strains. This new database was tested with 34 clinical isolates and could identify 29 strains correctly. Strains that remained unidentified were 2 Corynebacterium aurimucosum (not included in our database), 1 C. afermentans afermentans, and 2 Corynebacterium pseudodiphtheriticum. Cellular fatty acid analysis with a self-created database can be used for the identification and differentiation of corynebacteria.

Extended-Spectrum beta-lactamase (ESBL) producing Enterobacter aerogenes phenotypically misidentified as Klebsiella pneumoniae or K. terrigena.

BACKGROUND: Enterobacter aerogenes and Klebsiella pneumoniae are common isolates in clinical microbiology and important as producers of extended spectrum beta-lactamases (ESBL). The discrimination between both species, which is routinely based on biochemical characteristics, is generally accepted to be straightforward. Here we report that genotypically unrelated strains of E. aerogenes can be misidentified as K. pneumoniae by routine laboratories using standard biochemical identification and using identification automates. RESULTS: Ten clinical isolates, identified as K. pneumoniae or K. terrigena with the routinely used biochemical tests and with API-20E, were identified as E. aerogenes by tDNA-PCR - an identification that was confirmed by 16S rRNA gene sequencing for five of these isolates. Misidentification also occurred when using the automated identification systems Vitek 2 and Phoenix, and was due to delayed positivity for ornithine decarboxylase and motility. Subculture and prolonged incubation resulted in positive results for ornithine decarboxylase and for motility. It could be shown by RAPD-analysis that the E. aerogenes strains belonged to different genotypes. CONCLUSIONS: Clinical E. aerogenes isolates can be easily misidentified as Klebsiella due to delayed positivity for ornithine decarboxylase and motility. The phenomenon may be widespread, since it was shown to occur among genotypically unrelated strains from different hospitals and different isolation dates. A useful clue for correct identification is the presence of an inducible beta-lactamase, which is highly unusual for K. pneumoniae. In several instances, the use of genotypic techniques like tDNA-PCR may circumvent problems of phenotypic identification.

Yersinia enterocolitica in sheep--a high frequency of biotype 1A.

BACKGROUND: Pigs are regarded as the main reservoir for human pathogenic Yersinia enterocolitica, which is dominated by bioserotype 4/O:3. Other animals, including sheep, have occasionally been reported as carriers of pathogenic strains of Y. enterocolitica. To our knowledge, this is the first study performed in the Nordic countries in which the presence of Y. enterocolitica in sheep is investigated. METHODS: Tonsils and faecal samples collected from sheep slaughtered on the island Gotland (Sweden) from September 2010 through January 2011 were analysed for presence of Y. enterocolitica. In an attempt to maximize recovery, several cultural strategies were applied. Various non-selective media were used and different temperatures and durations of the enrichment were applied before subculturing on Cefsulodin Irgasan Novobiocin (CIN) agar. Presumptive Y. enterocolitica colonies were subjected to urease, API 20E and agglutination test. Yersinia enterocolitica isolates were biotyped, serotyped, and tested for pathogenicity using a TaqMan PCR directed towards the ail-gene that is associated with human pathogenic strains of Y. enterocolitica. RESULTS: The samples collected from 99 sheep yielded 567 presumptive Y. enterocolitica colonies. Eighty urease positive isolates, from 35 sheep, were identified as Y. enterocolitica by API 20E. Thirty-four of 35 further subtyped Y. enterocolitica isolates, all from faecal samples, belonged to biotype 1A serotype O:5, O:6. O:13,7 and O:10. One strain was Yersinia mollaretii serotype O:62. No human pathogenic strains of Y. enterocolitica were found in the investigated sheep. Other species identified were Y. kristensenii (n = 4), Y. frederiksenii/intermedia (n = 3), Providencia rettgeri (n = 2), Serratia marcescens (n = 1) and Raoultella ornithinolytica (n = 1). CONCLUSIONS: This study does not support the hypothesis that sheep play an important role in transmission of the known human pathogenic Y. enterocolitica in the studied geographical region. However, because there are studies indicating that some strains of Y. enterocolitica biotype 1A may cause disease in humans, the relative importance of sheep as carriers of human pathogenic strains of Y. enterocolitica remains unclear. Tonsils do not appear to be favourable sites for Y. enterocolitica biotype 1A in sheep.

Chryseobacterium arothri Campbell et al. 2008 is a later heterotypic synonym of Chryseobacterium hominis Vaneechoutte et al. 2007.

The type strains of the species Chryseobacterium arothri (DSM 19326(T)) and Chryseobacterium hominis (NF802(T)) were compared in order to clarify the taxonomic relationship of the two species. The 16S rRNA gene sequences of the two strains shared 99.9 % identity. DNA-DNA pairing studies between the two strains showed 100 % (reciprocal, 76.0 %) relatedness. Phenotypic data, including fatty acid patterns and substrate utilization profiles, showed no pronounced differences between the type strains of the two species. On the basis of these results, we propose the reclassification of Chryseobacterium arothri Campbell et al. 2008 as a later heterotypic synonym of Chryseobacterium hominis Vaneechoutte et al. 2007.

Transfer of Sejongia antarctica, Sejongia jeonii and Sejongia marina to the genus Chryseobacterium as Chryseobacterium antarcticum comb. nov., Chryseobacterium jeonii comb. nov. and Chryseobacterium marinum comb. nov.

The genus Sejongia was described in 2005, with the two species Sejongia antarctica and Sejongia jeonii, mainly on the basis of 16S rRNA gene sequence analysis. At that time, these organisms formed a quite separate branch in a 16S rRNA gene sequence-based tree, but, in subsequent studies, it became obvious that the species S. antarctica and S. jeonii and a third species, Sejongia marina, were most closely related (>95.0% similarity) to some Chryseobacterium species (e.g. Chryseobacterium hominis, C. formosense and C. haifense). In addition, there is no evidence for clear phenotypic (i.e. chemotaxonomic) differences between these organisms that justifies their assignment to different genera. For these reasons, a proposal is made to transfer these species to the genus Chryseobacterium as Chryseobacterium antarcticum comb. nov. (type strain AT1013T=JCM 12381T=IMSNU 14040T=KCTC 12225T), Chryseobacterium jeonii comb. nov. (type strain AT1047T=JCM 12382T=IMSNU 14049T=KCTC 12226T) and Chryseobacterium marinum comb. nov. (type strain IMCC3228T=KCCM 42689T=NBRC 103143T) on the basis of 16S rRNA gene sequence data and published phenotypic data.

Kytococcus schroeteri infection of a ventriculoperitoneal shunt in a child.

Kytococcus schroeteri is a newly described micrococcal species and, to date, has been associated mostly with endocarditis. Six infections attributable to this opportunistic pathogen have been described since 2002, when the first case was identified. We describe here the first pediatric case of a K. schroeteri ventriculoperitoneal shunt infection. The child was successfully treated with a combination of rifampin and vancomycin and shunt replacement. Initially identified as a Micrococcus spp. by both automated identification and conventional biochemical testing, sequencing of the 16S ribosomal RNA gene enabled accurate identification of the organism.

Description of Chryseobacterium anthropi sp. nov. to accommodate clinical isolates biochemically similar to Kaistella koreensis and Chryseobacterium haifense, proposal to reclassify Kaistella koreensis as Chryseobacterium koreense comb. nov. and emended description of the genus Chryseobacterium.

A collection of eight strains, NF 1366(T), NF 450, NF 1101, NF 1107, NF 1123, NF 1413, CCUG 15260 and CCUG 15624, from various clinical origins, were characterized biochemically as similar to Kaistella koreensis and Chryseobacterium haifense. They differed from K. koreensis, which is unable to alkalinize acetate, and from C. haifense, which is ONPG-positive (beta-galactosidase) and acidifies sucrose, fructose and lactose. Based on 16S rRNA gene sequence comparisons, this collection of strains was most closely related to the type strains of K. koreensis (97.3-97.5 %) and C. haifense (99.1 %). Representative strain NF 1366(T) showed only 41.8 % DNA-DNA relatedness with K. koreensis DSM 12107(T) and only 51.9 % with C. haifense DSM 19056(T). DNA-DNA hybridization of strains NF 450 and CCUG 15624 to strain NF 1366(T) was 41.7 and 74.6 %, respectively, and relatedness of these strains with C. haifense DSM 19056(T) was 72.6 and 70.2 %. With the present information, these two strains must be classified as intermediate between C. haifense and strain NF 1366(T). The fatty acid composition and polar lipid profile of strain NF 1366(T) were similar to those reported for other Chryseobacterium species. Like other chryseobacteria, strain NF 1366(T) exhibited a polyamine pattern with the predominant compound sym-homospermidine and a quinone system consisting of menaquinone MK-6 only. For this collection of clinical strains, the name Chryseobacterium anthropi sp. nov. is proposed, with NF 1366(T) (=CCUG 52764(T) =CIP 109762(T)) as the type strain. K. koreensis was shown to be very similar genotypically and phenotypically to Chryseobacterium. Its polar lipid profile exhibited the major characteristics shown for recently described Chryseobacterium species and the fatty acid profile of K. koreensis was also very similar to those of the Chryseobacterium species. Hence, no striking genotypic or phenotypic differences could be found that could justify the classification of this species into a separate genus, and we therefore propose to reclassify Kaistella koreensis in the genus Chryseobacterium as Chryseobacterium koreense comb. nov. (type strain Chj707(T) =IAM 15050(T) =JCM 21512(T) =KCTC 12107(T) =NBRC 103027(T)). An emended description of the genus Chryseobacterium is also proposed.

Chryseobacterium hominis sp. nov., to accommodate clinical isolates biochemically similar to CDC groups II-h and II-c.

A collection of eight clinical strains from Belgian hospitals and three clinical strains of the CCUG collection were characterized biochemically as being similar to CDC groups II-h and II-c; the latter differs from group II-h only by positivity for sucrose acidification. These 11 strains were found to cluster according to 16S rRNA gene sequence similarity at a level of >or=99.5%, and on the basis of their tDNA-PCR profile. Based on 16S rRNA gene sequence analysis, this collection of strains was related most closely to Chryseobacterium hispanicum (97.2%), but they differed from the type strain of this species by the following phenotypic characteristics: growth at 37 degrees C, negativity for xylose acidification, positivity for acetate assimilation-alkalinization on Simmons' agar base and absence of flexirubin pigments, and by their tDNA-PCR profile. Strain NF802T showed only 57.8% DNA-DNA relatedness to the type strain of C. hispanicum. Fatty acid composition did not enable differentiation from C. hispanicum. The DNA G+C content of strain NF802T is 36.5 mol%. The name Chryseobacterium hominis sp. nov. is proposed for this taxon, with type strain NF802T (=CCUG 52711T=CIP 109415T).

Alloscardovia omnicolens gen. nov., sp. nov., from human clinical samples.

The taxonomic position of 12 isolates tentatively assigned to the genus Bifidobacterium on the basis of a limited phenotypic characterization was examined. The isolates were collected between 1978 and 2005 in Belgium, Sweden and Norway, and originated from various human clinical samples, including urine, blood, urethra, oral cavity, tonsil, and abscesses of lung and aortic valve. On the basis of band number and clustering analysis, repetitive DNA element-based PCR fingerprinting using the BOXA1R and (GTG)(5) primers indicated that the clinical isolates represented a taxon probably not belonging to the genus Bifidobacterium. Analysis of 16S rRNA gene sequence similarities revealed that the isolates were most closely affiliated to Parascardovia denticolens LMG 18312(T) (93.0-93.2 %), Scardovia inopinata LMG 18313(T) (92.9-93.1 %) and other members of the Bifidobacteriaceae, indicating that the isolates belong to a novel genus within that family. This observation was further substantiated by the results of partial sequencing of the heat-shock protein 60 gene (hsp60) and determination of the DNA G+C contents (47.3-48.3 mol%). Members of the novel taxon can be phenotypically distinguished from S. inopinata, P. denticolens and Gardnerella vaginalis by the ability to grow on agar under aerobic conditions and on the basis of positive reactions for acid production from L-arabinose, raffinose, salicin and D-xylose. Unambiguous phenotypic differentiation from Aeriscardovia aeriphila and Bifidobacterium species may be difficult, so phenotypic analyses should be complemented by molecular methods. The values for DNA-DNA binding among four members of the novel genus were in the range of 89-100 %, indicating that the strains should be considered as a single novel species of a novel genus, for which the name Alloscardovia omnicolens gen. nov., sp. nov. is proposed. The type strain of Alloscardovia omnicolens is CCUG 31649(T) (=LMG 23792(T)).

Mycobacterium mucogenicum sepsis in an immunocompetent patient.

We report a case of Mycobacterium mucogenicum sepsis in an immunocompetent woman with Münchausen syndrome presenting with multiple abscesses.

Streptococcus cristatus isolated from a resected heart valve and blood cultures: case reports and application of phenotypic and genotypic techniques for identification.

BACKGROUND: Viridans streptococci are known as an important cause of endocarditis, but at present no cases of endocarditis caused by Streptococcus cristatus have been published, probably because phenotypic identification of viridans streptococci is tedious. Using tDNA-PCR, it is possible to identify to species level and to differentiate between species of the viridans group.

Distribution of nocardia species in clinical samples and their routine rapid identification in the laboratory.

Eighty-six Nocardia strains isolated from clinical samples in Belgium were identified by 16S rRNA gene sequencing. Eighty-three (96%) strains belonged to only six Nocardia species: N. farcinica (38 [44%]), N. nova (19 [22%]), N. cyriacigeorgica (13 [15%]), N. brasiliensis (6 [6.9%]), N. abscessus (5 [5.8%]), and N. paucivorans (2 [2.3%]). A gallery of nine conventional and enzymatic tests was developed for the rapid identification of the most common species isolated during this survey. Pyrrolidonyl aminopeptidase, gamma-glutamyl aminopeptidase, alpha-mannosidase, and alpha-glucosidase were found to be highly discriminating and could be used to develop an identification scheme.

Multilocus sequence typing for studying genetic relationships among Yersinia species.

The intra- and interspecies genetic relationships of 58 strains representing all currently known species of the genus Yersinia were examined by multilocus sequence typing (MLST), using sequence data from 16S RNA, glnA, gyrB, recA, and Y-HSP60 loci. Yersinia aldovae, Y. bercovieri, Y. intermedia, Y. pestis, Y. pseudotuberculosis, Y. rohdei, and Y. ruckeri were genetically more homogeneous than were Y. enterocolitica, Y. frederiksenii, Y. kristensenii, and Y. mollaretii. The MLST data concerning the genetic relatedness within and among various species of Yersinia support the idea that Y. pestis and Y. pseudotuberculosis are two lineages within the same species rather than two distinct species. Y. ruckeri is the genetically most distant species within the genus. There was evidence of O-antigen switching and genetic recombination within and among various species of Yersinia. The genetic relatedness data obtained by MLST of the four housekeeping genes and 16S RNA agreed in most, but not all, instances. MLST was better suited for determining genetic relatedness among yersiniae than was 16S RNA analysis. Some strains of Y. frederiksenii and Y. kristensenii are genetically less related to other strains within those species, compared to strains of all other species within the genus. The taxonomic standing of these strains should be further examined because they may represent currently unrecognized Yersinia species.

Evaluation of arbitrarily primed polymerase chain reaction analysis for typing Legionella pneumophila.

OBJECTIVE: To evaluate the performance of arbitrarily primed polymerase chain reaction (AP-PCR) analysis in epidemiologic typing of Legionella pneumophila. METHODS: Sixty-two isolates of L. pneumophila of serogroups 1, 3, 6 and 10, including epidemiologically related and unrelated isolates, were analyzed by AP-PCR using the primer BG2. Twenty-six of the serogroup 1 isolates were typed by pulsed-field gel electrophoresis (PFGE). RESULTS: AP-PCR analysis showed 98% typeability and complete reproducibility. A majority of unrelated isolates of each serogroup could be distinguished (discrimination index: 92%). Clinical isolates showed AP-PCR patterns indistinguishable from those of the isolates of the related environmental source. PFGE and AP-PCR results were in agreement for 88% of isolates. CONCLUSIONS: Single-primer AP-PCR analysis can be used as a simple and reproducible screening method for typing L. pneumophila strains of different serogroups.

Histidine decarboxylase in Enterobacteriaceae revisited.

With a modification of Taylor's decarboxylation broth, histidine decarboxylase was detected in Enterobacter aerogenes, Morganella morganii, Raoultella ornithinolytica, and some strains of Citrobacter youngae and Raoultella planticola. This method provides a useful confirmatory test for identification of E. aerogenes strains.

Biochemical and susceptibility tests useful for identification of nonfermenting gram-negative rods.

Six hundred nineteen strains of nonfermenting gram-negative rods were tested for alkaline phosphatase, benzyl-arginine arylamidase, pyrrolidonyl arylamidase, ethylene glycol acidification, and susceptibility to desferrioxamine and colistin. The results were highly discriminant. Therefore, the proposed tests may be helpful for the identification of this group of organisms.