Bacteremia caused by a novel species of Sphingobacterium

A Gram-negative rod was isolated from the blood cultures of an 84-year-old man with foot cellulitis. The bacterium was first identified as Sphingobacterium spiritivorum on the basis of standard assimilation tests. However, sequencing analysis of its 16S rRNA genes and whole genome hybridization studies with other related bacteria showed that this isolate belongs to a so far undescribed species of Sphingobacterium , close to S. mizutae . This bacterium was susceptible to most of the antibiotics tested, including glycopeptides, but was resistant to aminoglycosides and polymyxins. Treatment with amoxicillin–clavulanate cured the infection.     

Endocarditis caused byAerococcus urinae,a newly recognized pathogen

Aerococcus urinae is a newly described pathogen. A case ofAerococcus urinae endocarditis is presented, the primary focus being a urinary tract infection. The diagnosis of endocarditis was supported by isolation ofAerococcus urinae from blood as well as from heart vegetations.     

Bacteremia caused by a recently described novel Desulfovibrio species.

An obligately anaerobic, fastidious, slowly growing, spiral, gram-negative bacterium was isolated from the blood of a 75-year-old man with acute onset of pyrexia. The patient responded rapidly to appropriate antibiotic therapy. Extensive investigation failed to detect a focus for the infection. Phenotypically, the organism was consistent with Desulfovibrio species. Microscopic investigation revealed an organism with a vibrioid or spirillioid morphology with rapidly progressive motility by means of a single polar flagellum. Biochemically, the organism produced large amounts of H2S and contained desulfovirdin. The 16S rRNA gene sequence of the organism was found to be most similar to those of members of the genus Desulfovibrio, with identical sequence homology to the newly proposed species described by Tee et al. (W. Tee, M. Dyall-Smith, W. Woods, and D. Eisen, J. Clin. Microbiol. 34:1760-1764, 1996). This is a second unrelated isolation of this novel species from two widely different locations in Australia. The two isolates show some phenotypic differences, indicating that they are different strains of the same species.     

Bacteremia caused by an undescribed species of Janibacter

A yellow-pigmented rod- to coccoid-shaped coryneform microorganism was isolated from the blood of a patient with acute myeloid leukemia. It was identified by 16S rRNA gene sequencing as a previously undescribed species of Janibacter. The isolate was susceptible to penicillins, aminoglycosides, fluoroquinolones, and glycopeptides.     

Illness associated with Campylobacter laridis, a newly recognized Campylobacter species.

Campylobacter laridis, a recently described thermophilic Campylobacter species found principally in seagulls, has not previously been linked to illness in humans. Six clinical isolates of this species were referred to the national campylobacter reference laboratory in 1982 and 1983. Each isolate was confirmed by biochemical characterization and by DNA relatedness studies. The six isolates were obtained during an illness: enteritis in four, severe crampy abdominal pain in one, and terminal bacteremia in an immunocompromised host in one. The infections occurred in persons 8 months to 71 years old. Neither the geographic distribution nor the reports of the patients suggest that seagulls played a direct role in the epidemiology of these infections. This potential human enteric pathogen appears to be clinically, epidemiologically, and microbiologically similar to Campylobacter jejuni and may be mistaken for it if nalidixic acid susceptibility screening is not routinely performed.     

Characterization of and application of monoclonal antibodies against Rickettsia africae, a newly recognized species of spotted fever group rickettsia.

Rickettsia africae is a newly described species which causes African tick bite fever. Mediterranean spotted fever caused by R. conorii is endemic in the same regions of Africa as tick bite fever, and differentiation of the two syndromes by characterization of their etiological agents is important for epidemiological studies. R. africae and R. conorii are, however, difficult to distinguish, and therefore, our aim was to produce monoclonal antibodies to address this problem. Monoclonal antibodies were produced against R. africae by fusing splenocytes from BALB/C mice immunized with purified rickettsial organisms and SP2/0-Ag14 myeloma cells. A total of 355 hybridomas producing monoclonal antibodies to R. africae were identified by initial screening with six different antigens by microimmunofluorescence assay. A panel of 23 representative monoclonal antibodies were selected and subcloned. This panel was screened with a further 17 different spotted fever group (SFG) rickettsial reference antigens. Of these 23 monoclonal antibodies, 1 cross-reacted with only R. parkeri, whereas the others cross-reacted with more than two different antigens. Immunoblotting indicated that all the monoclonal antibodies were directed against the epitopes on two major high-molecular-mass heat-labile proteins, of which the molecular masses were 128 and 135 kDa, respectively. This monoclonal antibody panel was used successfully to identify R. africae in the blood culture of an infected patient, in infected cells within shell vials, and in infected ticks collected from Africa. Furthermore, the cross-reactivity of each SFG rickettsia with each of these 23 monoclonal antibodies was scored and was used to build a dendrogram of taxonomic relatedness between R. africae and the other SFG rickettsiae on the basis of Jaccard coefficients and unweighted pair group method with arithmetic mean analysis. The relatedness was generally consistent with that obtained by other methods of comparison.     

Bacteremia caused by Brevibacterium species in a patient with chronic lymphocytic leukemia

We report a case of bacteremia caused by Brevibacterium species which is one of the coryneform bacteria, in a patient with chronic lymphocytic leukemia. We conclude that, if a coryneform bacteria is isolated from sterile body sites, it must be carefully evaluated, and especially in immunocompromised patients, Brevibacterium species should be considered as potential pathogens.     

A newly recognized fastidious gram-negative pathogen as a cause of fever and bacteremia

BACKGROUND. We identified a motile, curved, gram-negative bacillus as the cause of persistent fever and bacteremia in two patients with symptomatic human immunodeficiency virus infection. The same organism was subsequently recovered from a bone marrow-transplant recipient with septicemia and from two immunocompetent persons with week-long febrile illnesses. All the patients recovered after antimicrobial therapy. METHODS AND RESULTS. Primary cultures of blood processed by centrifugation after blood-cell lysis yielded adherent, white, iridescent, morphologically heterogeneous colonies in 5 to 15 days. Subcultures grew in four days on chocolate, charcoal-yeast extract, or blood agar. The organisms stained weakly with safranin and were not acid-fast. Fluorescent-antibody tests for legionella and francisella were negative. Biochemical reactivity was minimal and difficult to ascertain. Agar-dilution testing revealed in vitro susceptibility to most antimicrobial agents tested. The cellular fatty acid composition of the isolates was similar, resembling that of Rochalimaea quintana or brucella species, but not Helicobacter pylori or species of campylobacter or legionella. As resolved by gel electrophoresis, cell-membrane preparations of all isolates contained similar proteins, with patterns that differed from that of R. quintana. Patterns of digestion of DNA from all isolates by EcoRV restriction endonuclease were virtually identical and also differed from that of R. quintana. On immunodiffusion, serum from one convalescent patient produced a line of identity with sonicates of all five isolates. CONCLUSIONS. This pathogen may have been unidentified until now because of its slow growth, broad susceptibility to antimicrobial agents, and possible requirement of blood-cell lysis for recovery in culture. It should be sought as a cause of unexplained fever, especially in persons with defective cell-mediated immunity.     

Bacteremia caused by Achromobacter species in an immunocompromised host.

A case of bacteremia caused by Achromobacter species in an immunocompromised patient is described. The patient responded to antibiotic therapy. Detailed antibiotic susceptibility data are presented.     

Pneumonia caused by a newly recognized pseudomonad in a child with chronic granulomatous disease.

A pseudomonad was isolated from the pleural fluid and pulmonary decortication tissue of a 5-year-old child with chronic granulomatous disease. Although the isolate was phenotypically similar to Pseudomonas cepacia, its biochemical profile was more similar to that of Pseudomonas pickettii biovar 2. Its slow growth rate, ability to hydrolyze urea rapidly, and lateral and polar flagellar pattern were suggestive of Oligella ureolytica (formerly CDC group IVe). The cellular fatty acid composition was similar to that of P. cepacia and Pseudomonas gladioli, except for the presence of dodecanoic acid. Numerical analysis of the fatty acid data supported the interrelatedness of the isolate with other species of the pseudomallei group (rRNA homology group II) of Pseudomonas. The organism described in this report is an addition to the growing list of catalase-positive organisms which can potentially cause severe morbidity in patients with chronic granulomatous disease.     

The neuropathology in toxoplasmosis-like infection caused by a newly recognized cyst-forming sporozoon in dogs

The pathomorphological changes in the central nervous system associated with an infection with a previously reported, Toxoplasma-like, cyst-forming sporozoon were studied by means of light microscopy, including immunohistochemistry, and transmission electron microscopy in seven dogs, aged 4 months to 2 years. Tachyzoites (endozoites) within parasitophorous vacuoles were found in neurons, astrocytes, macrophages, vascular pericytes and probably also in fibroblasts, while cyst stages were only observed in cells showing features of neurons. Proliferating tachyzoites were associated with lesions of a necrotic/granulomatous type. Perivascular accumulations of lymphocytes and plasma cells, together with an activation of astrocytes and perivascular fibroblasts resulting in marked sclerosis, were prominent features in all cases. The grey matter was most seriously affected in the brain, while the white matter was most often the site of inflammation in the spinal cord. The structural similarity to the newly reported Neospora caninum suggests that we are dealing here with the same parasite. However, the present infection and toxoplasmosis have so many features in common, including the light microscopical morphology of the organisms and host/parasite relationship, that a definite etiological diagnosis should be based on ultrastructural and/or immunohistochemical examinations.     

Bacteremia caused by a lactose-fermenting, multiply resistant Salmonella typhi strain in a patient recovering from typhoid fever.

A female patient suffered a typical attack of typhoid fever due to a lactose-negative, fully susceptible Salmonella typhi strain. During convalescence she became febrile, and a lactose-fermenting S. typhi strain resistant to ampicillin, chloramphenicol, tetracycline, and trimethoprim was isolated from blood culture. This isolated was shown to harbor a plasmid which cotransferred lactose fermentation and antibiotic resistance.     

Toluca-1, a newly recognized enterovirus

Summary The characteristics of a hemagglutinating enterovirus, Toluca-1, are described. The virus appears to be sufficiently distinct from all previously described enteroviruses to be considered a new serotype.This work was supported in part by Grant AI-01475 and Contract NIH 69 — 89 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, U.S.A.     

Bacteremia caused by a novel helicobacter species in a 28-year-old man with X-linked agammaglobulinemia

We report on a case of bacteremia caused by a previously unknown urease-negative Helicobacter strain, IMMIB HP-28/08, isolated from blood cultures of a 28-year-old man with X-linked agammaglobulinemia. The identification of the isolate was based on 16S rRNA gene sequencing. In the phylogenetic tree, the isolate fell into a cluster which included Helicobacter canadensis, Helicobacter equorum, and Helicobacter pullorum. This is the first report of bacteremia caused by this fastidious organism. Further investigations are necessary to determine the potential role of this species as a pathogen of bloodstream infections.     

Bacteremia caused byBrevibacterium species in an immunocompromised patient

A 46-year-old woman suffering from non-Hodgkin's lymphoma was admitted to the hospital because of high fever. Multiple blood cultures revealed an unusual finding, aBrevibacterium species, which was reisolated 16 days later from the tip of her long-term central venous catheter. This case indicates thatBrevibacterium species isolated from normally sterile sites should be considered as a potential pathogen, especially in immunocompromised patients.     

Bacteremia caused by Clostridium intestinale

We describe a case of Clostridium intestinale bacteremia in a previously healthy adolescent female presenting with fever and abdominal pain. The bacterium was definitively identified via 16S rRNA gene sequencing. This is the first report, in the world literature, of human infection caused by this microorganism.     

Bacteremia caused by Janibacter melonis

We report a case of bacteremia caused by Janibacter melonis, a recently described aerobic actinomycete originally isolated from a spoiled oriental melon. Our patient's blood culture isolate was identified by partial 16S rRNA gene sequencing. This is the first report of the recovery of Janibacter species from humans.     

Bacteremia caused by Clostridium symbiosum

We describe a fatal case of Clostridium symbiosum bacteremia in a 70-year-old man with metastatic colon cancer. Our report is the first, in the world literature, of human infection caused by this microorganism.