Epidemiology

Shigella generally is considered to have a narrow distribution in nature, inhabiting essentially the intestinal tract of humans, as well as captive primates in which shigellosis naturally occurs. There is no evidence, however, that the disease naturally occurs, particularly in the wild in those monkeys, without prior contact with humans (Carpenter et al., 1965 Takasaka et al., 1964). Although shigellae are difficult, if not impossible, to grow from environmental samples, they are consistently...

Specific Immune Response Against Shigella Infection

Most of our knowledge of the specific (adaptive) immune response against Shigella has been collected from observations in humans. Evidence indicates that Shigella infection confers protective immunity, although its mechanisms are not fully understood. Among the evidence is the fact that shigellosis peaks during the first five years of life and subsequently declines, suggesting that immunity occurs following repeated exposures to Shigella during childhood (Taylor et al., 1986). Also, the...

Bacterial Relationships and Realities

The living world is organized taxonomically into three domains Archaea, Bacteria and Eucarya which have been delineated in terms of their SSU rRNA sequences and cell membrane structures (Woese et al., 1990 Winker and Woese, 1991). Despite the prevailing nomenclature, Bacteria are the most ancient and are estimated to have appeared between 3.5 and 4 billion years ago. Bacteria comprise about 40 phyla (i.e., deep-branching subdivisions), about one-third of which presently contain representatives...

Enteriobacteriaceae Whats in a Name

Even for the most extensively studied group of the Bacteria, recent molecular phylogenetic analyses have revealed some unrecognized kinships between taxa as well as numerous inconsistencies in the present classification scheme. The Enterobacteriaceae are Gram-negative, facultatively anaerobic rods belonging to the y-class of Proteobacteria. Only a few actually reside in an enteric environment however, most fall within a group of related species that colonize the mammalian intestine. There are...

Cell Structure

Escherichia coli are Gram-negative, nonspore-forming bacilli. They are approximately 0.5 im in diameter and 1.0-3.0 im in length. Within the periplasm is a single layer of peptidoglycan. The peptidoglycan has a typical subunit structure where the N-acetylmuramic acid is linked by an amide bond to a peptide consisting of L-alanine, D-glutamic acid, meso-diaminopimelic acid and finally D-alanine. Escherichia coli are commonly motile in liquid by means of peritrichous flagella. Swarming behavior...

N I

Schematic representation of the crossing, rupture, invasion and inflammatory destruction of the intestinal barrier by Shigella. to diagnose Shigella infection in retrospect (Lindberg et al., 1991 Cam et al., 1993). Bacteriological methods for isolation of Shigella from feces are widely available. Shigella are present in the feces of patients in concentrations ranging from 103-109 viable bacteria per gram during the acute phase of the disease, but they readily die off if the stool...

Arsenophonus Androcidium

In 1986, Werren et al. isolated the causative agent (Arsenophonus nasoniae) of the son-killer (sk) trait from infected tissues of the parasitic wasp, Nasonia vitropennis. The sk trait, a sexratio distorter, is carried by approximately 5 of female wasps from natural populations (Gherna et al., 199l). Infected wasps transmit the bacterium to fly pupae (wasp host) during oviposition and offspring then become infected perorally (Werren et al., 1986). The bacterium causes the death of only male wasp...

Disease Manifestations

As noted in Table 9, both E. ictaluri and E. tarda are important pathogens of fish (Frerichs, 1985 Thune et al., 1993). The causative agent of enteric septicemia of catfish (ESC Fig. 4), E. ictaluri is responsible for enormous economic losses to the channel catfish industry, the largest aquaculture business in the United States (Hawke et al., 1981). A 1988 fish mortality summary for catfish listed E. ictaluri (n 1,169) as the leading cause of death, accounting for 48 of all cases reported...

Bacteriological Characters

The genus Shigella consists of four species, S. dysenteriae (subgroup A), S. flexneri (subgroup B), S. boydii (subgroup C) and S. sonnei (subgroup D), characterized by biochemical and serological properties. The subgroup A differs from the other subgroups by its inability to ferment mannitol. Shigella serotypes are differentiated on the basis of their somatic O antigens. Shigella spp. express numerous negative characters. Isolates are always nonmotile and nonflagellated. They do not grow on...

Yokenella Koserella

In 1985, Hickman-Brenner et al. proposed the name Koserella trabulsii for a biochemical and phylogenetically new taxa that had been previously referred to by a number of vernacular names including Hafnia species 3 and CDC Enteric Group 45 (Farmer et al., 1985 Brenner, 1991). Kosako et al. (1984) independently concluded that a group of strains resembling H. alvei, called NIH (Japan) biogroup 9, was a single DNA relatedness group that they named Yokenella regensburgei. These two groups were...

Usa

Department of Biotechnology Engineering Institute for Applied Biological Research Environmental Biotechnology Institute Ben Gurion University 84105 Beer-Sheva Israel Director of Graduate Studies in Pathology Departments of Pathology, Molecular Genetics and Microbiology, and Immunology Duke University Medical Center Durham, NC 27710 USA School of Biochemistry and Microbiology University of Leeds Leeds LS2 9JT UK Faculty of Medicine, Nursing and Health Sciences Department of Microbiology Clayton...

Buttiauxella

The genus Buttiauxella consists of seven named species whose primary ecologic niche appears to be as inhabitants of mollusks (M ller et al., 1996). The genus was initially defined by Ferra-gut and others in 1981 when a taxon previously designated group F was formerly proposed as a new genus, Buttiauxella, with a single species, B. agrestis. However, from the early onset it was clear that additional unrecognized species within the genus existed. Over a decade later, the genus was amended to...

Xenorhabdus

In 1965, Poinar and Thomas proposed the name Achromobacter nematophilus for the symbiotic organism found in the digestive tract of the nematode Steinernema (formerly Neoaplectana) feltiae. The genus name was subsequently rejected, resulting in a lengthy chronology of tax-onomic proposals naming the bacterial symbiont and its nematode host (for a review, see Forst and Nealson, 1996). In 1979, Thomas and Poinar proposed the new genus Xenorhabdus in the family Enterobacteriaceae for the nematode...

Pantoea

The genus Pantoea was created in 1989 by Gavini and colleagues to house two closely related taxa that had formerly resided in several genera, including Enterobacter and Erwinia. One taxon, referred to as DNA hybridization group (HG) 27155 by Beij and others (Beji et al., 1988) consisted of the type strain of Enterobacter agglom-erans (ATCC 27155) and strains belonging to the B4 phenom of Gavini et al. (1983a). An electro-phoretic protein analysis of these strains indicated that those belonging...

Antibiotic Susceptibility

Antibiotic resistance in Citrobacter species, as in other bacteria causing nosocomial infections, is an emerging problem. Citrobacter species without acquired antibiotic resistance are susceptible to sulfonamides, trimethoprim, aminoglycosides, chloramphenicol, tetracycline, nalidixic acid, flu oroquinolones, nitrofurantoin, polymyxins and fosfomycin (The Genus Citrobacter in the second edition Pepperell et al. 2002). Like other Enterobacteriaceae, Citrobacter species are resistant to...

Af025369

Original genomospecies numbers from Brenner et al. (1993) species names from Brenner et al. (1993), except C. rodentium (Schauer et al., 1995), and C. gillenii and C. mur-liniae (Brenner et al., 1999). Original genomospecies numbers from Brenner et al. (1993) species names from Brenner et al. (1993), except C. rodentium (Schauer et al., 1995), and C. gillenii and C. mur-liniae (Brenner et al., 1999). Citrobacter species are infrequently isolated from stool and occasionally cause infections in...

Budvicia

The genus Budvicia, with its single species B. aquatica, was first isolated and described by Aldova and colleagues in Czechslovakia in 1983 (Brenner, 1991). DNA relatedness studies on these strains and a formal genus and species proposal were subsequently reported collabora-tively by the Czech group and a group at the Pasteur Institute in Paris (Bouvet et al., 1985 Brenner, 1991).Phylogenetic analysis of the type strain of B. aquatica indicates that Budvicia forms a distinct lineage in the...

Photorhabdus

The genus Photorhabdus was proposed in 1993 to include bacterial endosymbionts of ento-mopathogenic nematodes that had previously been assigned to the genus Xenorhabdus as X. luminescens (Boemare et al., 1993). Creation of this new genus appeared warranted since X. luminescens strains were significantly different from all other known Xenorhabdus strains at that time on a genetic, phenotypic, physiologic and ecologic basis (Boemare et al., 1993). DNA relatedness studies conducted by Grimont et...

Disease

One of the most notable features of E. coli is broad diversity of disease-causing genotypes. As mentioned above, the diseases can encompass different symptoms and gastrointestinal tract pathologies, but there are also diseases at extraintestinal sites. These different genotypes and their disease-causing abilities lead to categories of E. coli often referred to as pathotypes. There are six intestinal and two extraintestinal pathotypes currently recognized Nataro and Kaper, 1998a Nataro et al.,...

Taxonomy and Phylogeny

The comparative analysis of 5S and 16S riboso-mal RNA sequences suggest that Escherichia and Salmonella diverged from a common ancestor between 120 and 160 million years ago, which coincides with the origin of mammals (Ochman and Wilson, 1987). Escherichia and Shigella have been historically separated into different genera within the Enterobacteriaceae. DNA sequence analysis of their genomes reveals a high degree of sequence similarity and suggests to many bacteriologists that they should be...

Brenneria

The genus Brenneria is composed of several necrogenic phytopathogenic species that formerly resided within the amylovora group of the genus Erwinia. Phylogenetic investigations conducted on 16 Erwinia species utilizing 16S rDNA sequence data identified four distinct clusters, one of which (cluster IV) contained the species E. salicis, E. nigrifluens and E. rubrifa-ciens (Kwon et al., 1997). Hauben et al. (1998a) analyzed the 16S rDNA sequences of 29 plant-associated strains and also identified...

Buchnera

The genus Buchnera consists of a single species, B. aphidicola, which is an obligate intracellular symbiont of the greenbug aphid, Schizaphis graminum (Munson et al., 1991). Buchera aphidicola cannot be cultured in vitro. The bacterium exists within 60-80 huge specialized aphid cells called bacteriocytes or mycetocytes located within host-derived membrane vesicles termed symbiosomes (Baumann et al., 1995). Buch-nera is vertically transmitted to eggs and offspring by a process that is not...

Rahnella

Gavini et al. (1976), during a study of the genus Enterobacter, used the name Group H2 for phenotypically similar, phenylalanine deami-nase-positive strains that may have been included in the Enterobacter agglomerans-Erwinia herbicola complex on the basis of their negative lysine- and ornithine decarboxylase reactions, and negative arginine dihydrolase reaction (Brenner, 1991). On the basis of DNA relatedness reactions on 12 of the 20 strains of Group H2, a single species, Rahnella aquatilis,...

Info

Identified) was recovered from a suprapubic aspirate and from blood. Luttrell et al. described a soft tissue infection of the right forearm in a healthy 37-year-old woman. She apparently acquired her Kluyvera infection (species not identified) after cutting herself on the open lid of a can in the garbage. A case of Kluyvera pyelonephritis (species not identified) has also been described in a five-year-old girl where > 100,000 cfu ml were recovered from a urine sample (Dollberg et al., 1990)...

L is il V

HEp2 cells invaded by E. tarda, magnification x 200. 1991b Ling et al., 2000). Subsequently, two p-hemolysins from E. tarda have been cloned and sequenced. The first, cloned from strain ET16, resides in an open-reading frame (ORF) of 933 bp encoding for a 311 amino acid polypeptide with a molecular mass of 34 kDa (Chen et al., 1996). The structural gene for this P-hemolysin shares over 90 homology to the hemolysin BL of Bacillus cereus (Hirono et al., 1997). The frequency of this gene...

Antimicrobial Susceptibility

All species of Edwardsiella are uniformly susceptible to all antibiotics or to all -lactam antibiotic- -lactamase inhibitor combinations (Table 7) that are used to treat gastrointestinal and systemic infections (Reinhardt et al., 1985 Reger et al., 1993 Clark et al., 1991). Interestingly, this includes the -lactam antibiotics even though all isolates of E. tarda tested to date have been found to produce -lactamases. None of thirteen E. hoshinae or ten E. ictaluri strains tested by Reger et al....

The Emergence of Bacterial Symbionts

The characterization of bacterial symbionts, which are broadly distributed and cannot be maintained outside of their animal hosts, has been one of the greatest successes of culture-independent methods for the identification and classification of microbes. Insects that feed exclusively on blood or plant sap contain obligate primary symbionts that offset their host nutritional deficiencies, reside within specialized host organs, and are essential for host survival. In addition to these primary...

Gastroenteritis

The mechanism by which serovar Typhimurium causes gastroenteritis is not completely clear, but the current model suggests it is caused by inflammation, increased fluid accumulation within the small intestine, and polymorphonuclear leukocyte PMN influx into the small intestine McCormick et al., 1995 Darwin and Miller, 1999b Zhang et al., 2003 . Most virulence studies on serovar Typhimurium use a mouse model of infection. One caveat is that a serovar Typhi-murium infection of a mouse unlike that...