Implications of <Emphasis Type="Italic">stx</Emphasis> loss for clinical diagnostics of Shiga toxin-producing <Emphasis Type="Italic">Escherichia coli</Emphasis>

The dynamics related to the loss of stx genes from Shiga toxin-producing Escherichia coli remain unclear. Current diagnostic procedures have shortcomings in the detection and identification of STEC. This is partly owing to the fact that stx genes may be lost during an infection or in the laboratory. The aim of the present study was to provide new insight into in vivo and in vitro stx loss in order to improve diagnostic procedures. Results from the study support the theory that loss of stx is a strain-related phenomenon and not induced by patient factors. It was observed that one strain could lose stx both in vivo and in vitro. Whole genome comparison of stx-positive and stx-negative isolates from the same patient revealed that different genomic rearrangements, such as complete or partial loss of the parent prophage, may be factors in the loss of stx. Of diagnostic interest, it was shown that patients can be co-infected with different E. coli pathotypes. Therefore, identification of eae-positive, but stx-negative isolates should not be interpreted as “Shiga toxin-lost” E. coli without further testing. Growth and recovery of STEC were supported by different selective agar media for different strains, arguing for inclusion of several media in STEC diagnostics.     

Host species-specific translocation of <Emphasis Type="Italic">Escherichia coli</Emphasis>

The purpose of this paper is to investigate the rate of translocation of Escherichia coli strains in different experimental/animal models. Four proficient translocating E. coli strains isolated from mesenteric lymph nodes (MLNs) and/or the blood of rats (strains KIC-1 and KIC-2), from a fatal case of pancreatitis (HMLN-1) and from pigs (PC-1 isolated in this study) were tested for their ability to translocate across two host species and the Caco-2 cell line as a model of the human gut epithelium. HMLN-1 was found in the MLNs of all 15 pigs tested. This strain, however, did not translocate in any rats and only colonised the caecum of four rats in small numbers. HMLN-1 and PC-1 were the dominant translocating strains in Caco-2 cells compared to KIC-1 and KIC-2, which were found to translocate at a lower rate in pigs and in Caco-2 cells. The rate of translocation of PC-1 in rats was also very low compared to KIC-1 and KIC-2. We suggest that, in studies aiming to investigate the mechanism of translocation of E. coli strains isolated from humans, rats may not be an appropriate animal model and that the Caco-2 cells or pigs are more suitable in vitro and in vivo models, respectively.     

Simultaneous real-time PCR detection of <Emphasis Type="Italic">Bacillus anthracis</Emphasis>, <Emphasis Type="Italic">Francisella tularensis</Emphasis> and <Emphasis Type="Italic">Yersinia pestis</Emphasis>

This report describes the development of in-house real-time PCR assays using minor groove binding probes for simultaneous detection of the Bacillus anthracis pag and cap genes, the Francisella tularensis 23 KDa gene, as well as the Yersinia pestis pla gene. The sensitivities of these assays were at least 1 fg, except for the assay targeting the Bacillus anthracis cap gene, which showed a sensitivity of 10 fg when total DNA was used as a template in a serial dilution. The clinical value of the Bacillus anthracis- and Francisella tularensis-specific assays was demonstrated by successful amplification of DNA from cases of cow anthrax and hare tularemia, respectively. No cross-reactivity between these species-specific assays or with 39 other bacterial species was noted. These assays may provide a rapid tool for the simultaneous detection and identification of the three category A bacterial species listed as biological threats by the Centers for Disease Control and Prevention.     

Chromosome elimination in the interspecific hybrid medaka between <Emphasis Type="Italic">Oryzias latipes</Emphasis> and <Emphasis Type="Italic">O. hubbsi</Emphasis>

An interspecific hybrid medaka (rice fish) between Oryzias latipes and O. hubbsi is embryonically lethal. To gain an insight into the cellular and molecular mechanisms that cause the abnormalities occurring in the hybrid medaka, we investigated the behavior of chromosomes and the expression patterns of proteins responsible for the chromosome behavior. The number of chromosomes in the hybrid embryos gradually decreased to nearly half, since abnormal cell division with lagging chromosomes at anaphase eliminated the chromosomes from the cells. The chromosome lagging occurred at the first cleavage and continued throughout embryogenesis even after the midblastula transition. Fluorescent in-situ hybridization analyses revealed that the chromosomes derived from O. hubbsi are preferentially eliminated in both O. latipes–hubbsi and O. hubbsi–latipes embryos. Whole-mount immunocytochemical analyses using antibodies against α-tubulin, γ-tubulin, inner centromere protein, Cdc20, Mad2, phospho-histone H3 and cohesin subunits (SMC1α, SMC3 and Rad21) showed that the expression patterns of these proteins in the hybrid embryos are similar to those in the wild-type embryos, except for phospho-histone H3. Phospho-histone H3 present on chromosomes at metaphase was lost from normally separated chromosomes at anaphase, whereas it still existed on lagging chromosomes at anaphase, indicating that the lagging chromosomes remain in the metaphase state even when the cell has proceeded to the anaphase state. On the basis of these findings, we discuss the cellular and molecular mechanisms of chromosome elimination in the hybrid medaka.     

SCC<Emphasis Type="Italic">mec</Emphasis> and <Emphasis Type="Italic">spa</Emphasis> types of methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> strains in Israel. Detection of SCC<Emphasis Type="Italic">mec</Emphasis> type V

Molecular characterization of methicillin-resistant Staphylococcus aureus isolates from three hospitals in Israel was the aim of the study presented here. We identified 11 distinct genetic clones by pulsed-field gel electrophoresis. Molecular typing identified four different SCCmec types—I, II, IV, and V−and nine spa types. Spa type t002 was the most common. An erratum to this article can be found at     

Use of Phenotyping and Genotyping to Verify Transmission of <Emphasis Type="Italic">Escherichia coli</Emphasis> O157:H7 from Dairy Farms

A total of 80 human infections by Escherichia coli O157:H7 were documented in Finland in 1997 and 1998. Most were sporadic and their sources undetermined. Five cases not associated with one another, one of which led to secondary transmission within a family, could be traced to five different dairy farms. These five case patients (age range 2–17 years, median age 3 years) were hospitalised with bloody diarrhoea; two of them developed haemolytic uraemic syndrome. All nine human isolates obtained were sorbitol negative, carried the verocytotoxin 2 and eae genes, and produced verocytotoxin and enterohaemolysin. The phage and pulsed-field gel electrophoresis types of the human and bovine isolates from the corresponding farms were indistinguishable. The cattle (20–70 animals per farm) were monitored for up to 2 years after the human cases. The proportion of cattle excreting the type that caused the human infections varied from 3.2 to 66.7% when sampled soon after the human cases, and from 0.0 to 5.3% about a year or so later. On most of the farms, the animals excreted the pathogen intermittently. On one farm, Escherichia coli O157 isolates with other characteristics were also occasionally isolated. Although the infections were traced back to the farms, it could not be established whether the source was unpasteurised milk or direct or indirect contact with cattle. The results of this study emphasise the need for special recommendations for children visiting or living on a farm to prevent these infections. Electronic Publication     

<Emphasis Type="Italic">Trichomonas vaginalis</Emphasis> harboring <Emphasis Type="Italic">Mycoplasma hominis</Emphasis> increases cytopathogenicity in vitro

The parasite Trichomonas vaginalis causes one of the most common non-viral sexually transmitted infections in humans. Mycoplasmas are frequently found with trichomonads but the consequences of this association are not yet known. In the present study, the effects of T. vaginalis harboring M. hominis on human vaginal epithelial cells and on MDCK cells are described. The results were analyzed by light, scanning and transmission electron microscopy, as well as using cell viability assays. There was an increase in the cytopathic effects on the epithelial cells infected with T. vaginalis associated with M. hominis compared to T. vaginalis alone. The epithelial cells exhibited an increase in the intercellular spaces, a lesser viability, and increased destruction provoked by the infected T. vaginalis. In addition, the trichomonads presented a higher amoeboid transformation rate and an intense phagocytic activity, characteristics of higher virulence behavior.     

Heterogeneity of the <Emphasis Type="Italic">ospA</Emphasis> gene structure from isolates of <Emphasis Type="Italic">Borrelia garinii</Emphasis> and <Emphasis Type="Italic">Borrelia afzelii</Emphasis> from Western Siberia and Mongolia

In this work, identification and analyses of 48 full-length sequences of the ospA gene isolates of Borrelia garinii and Borrelia afzelii from Western Siberia and Mongolia has been made. It was shown that B. garinii isolates was of its high genetic heterogeneity of the ospA gene. Four genetic groups of the ospA gene from the Ixodes persulcatus tick collected in of Western Siberia and Mongolia were defined. The basic differences in the genetic variants of the ospA gene considered are seen in regions which code for antibody determinants of thhe OspA protein.     

Chromosome pairing in allotetraploid hybrids of <Emphasis Type="Italic">Festuca pratensis</Emphasis> × <Emphasis Type="Italic">Lolium perenne</Emphasis> revealed by genomic <Emphasis Type="Italic">in situ</Emphasis> hybridization (GISH)

Genomic in situ hybridization (GISH) was used to make a detailed study of chromosome pairing at metaphase I (MI) of meiosis in six F(1) hybrid plants of the allotetraploid Festuca pratensis x Lolium perenne (2n = 4x = 28; genomic constitution FpFpLpLp). The mean chromosome configurations for all hybrids analysed were 1.13 univalents + 11.51 bivalents + 0.32 trivalents + 0.72 quadrivalents, and the mean chiasma frequency was 21.96 per cell. GISH showed that pairing was predominantly intragenomic, with mean numbers of L. perenne (Lp/Lp) and F. pratensis (Fp/Fp) bivalents being virtually equal at 5.41 and 5.48 per cell, respectively. Intergenomic pairing between Lolium and Festuca chromosomes was observed in 33.3% of Lp/Fp bivalents (0.62 per cell), in 79.7% of trivalents - Lp/Lp/Fp and Lp/Fp/Fp (0.25 per cell), and in 98.4% of quadrivalents - Lp/Lp/Fp/Fp and Lp/Lp/Lp/Fp (0.71 per cell). About 4.0% of the total chromosome complement analysed remained as univalents, an average 0.68 Lp and 0.45 Fp univalents per cell. It is evident that in these hybrids there is opportunity for recombination to take place between the two component genomes, albeit at a low level, and this is discussed in the context of compromising the stability of Festulolium hybrid cultivars and accounting for the drift in the balance of the genomes over generations. We speculate that genotypic differences between hybrids could permit selection for pairing control, and that preferences for homologous versus homoeologous centromeres in their spindle attachments and movement to the poles at anaphase I could form the basis of a mechanism underlying genome drift.     

Histopathologic and electron microscopic characterization of cutaneous leishmaniasis in <Emphasis Type="Italic">Tatera indica</Emphasis> and <Emphasis Type="Italic">Gerbillus</Emphasis> spp. infected with <Emphasis Type="Italic">Leishmania major</Emphasis>

Cutaneous leishmaniasis (CL) is a zoonotic disease transmitted between rodents and canines, mainly by Phlebotomus sand flies and man. In southern Iran, the incidence of this protozoan disease has doubled over the last decade. The present study deals with histopathological features of CL in Tatera indica and Gerbillus spp. that participate in the epidemiology of CL in southern Iran. Thirty-two trapped rodents were evaluated for any Leishmania infection using enzyme electrophoresis and polymerase chain reaction and were concomitantly studied for any histopathological changes. Histopathological studies showed that bone marrow was the tissue of choice for light and electron microscopic study of Leishmania, demonstrating the macrophages infected with the amastigote form of the parasite. This is the first report of the histopathological detection of L. major in naturally infected T. indica and Gerbillus spp in the Larestan region.     

Community-acquired <Emphasis Type="Italic">Acinetobacter</Emphasis> infections

Acinetobacter infections have been attracting increasing attention during recent years because they have become common in hospitalized patients, especially in the intensive care unit (ICU) setting. However, the available literature suggests that the pathogen has another fearful potential; it can cause community-acquired infections. We searched PubMed and the reference lists of the initially identified articles and identified six case series regarding a total of 80 patients with community-acquired Acinetobacter baumannii infections; from these, 51 had pneumonia and 29 had bacteremia. Of these 80 patients, 45 (56%) died of the infection. In addition, we identified 26 case reports regarding 43 patients with community-acquired Acinetobacter infections; from these, 38 had pneumonia, two had meningitis, one had soft-tissue infection, one had ocular infection, and one had native valve endocarditis. Comorbidity was commonly present in patients reported in the case series as well as the case reports, mainly, chronic obstructive pulmonary disease, renal disease, and diabetes mellitus; heavy smoking and excess alcohol consumption were also common. Most of the studies originated from China, Taiwan, and tropical Australia. We also identified 12 retrospective or prospective studies (seven from the Far East, two from Oceania, one from N. Guinea, one from Palestine, and one from USA/Canada) that reported the frequency of community-acquired Acinetobacter infections; the range of isolation of Acinetobacter from patients with community-acquired pneumonia in these studies was 1.3%-25.9%. In conclusion, most community-acquired Acinetobacter infections have been reported from countries with tropical or subtropical climate, and mainly affect patients with some form of comorbidity or are associated with heavy smoking and excess alcohol consumption.     

Comparison of <Emphasis Type="Italic">SYBR Green I</Emphasis> and <Emphasis Type="Italic">TaqMan</Emphasis> real-time PCR formats for the analysis of <Emphasis Type="Italic">her2</Emphasis> gene dose in human breast tumors

We compared two technologies of real-time PCR (with the use of fluorescent SYBR Green I dye and specific TaqMan probe) for quantification of the dose of her2 gene in breast tumors. The maximum increase in the gene dose in TaqMan and SYBR Green I analyses was 10-and 5-fold, respectively. In was found that TaqMan and SYBR Green I technologies allow detection of the matrix in amounts corresponding to 1–100 and 2.5–40.0 ng genomic DNA, respectively. Tenfold increase in the gene dose leads to incorrect evaluation of multiplication ratio in the SYBR Green I analysis. These results suggest that TaqMan technology is more preferable for correct evaluation of her2 gene dose. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 2, pp. 201–205, February, 2008     

Chromosome homology between mouse and three Muridae species, <Emphasis Type="Italic">Millardia meltada</Emphasis>, <Emphasis Type="Italic">Acomys dimidiatus</Emphasis> and <Emphasis Type="Italic">Micromys minutus</Emphasis>, and conserved chromosome segments in murid karyotypes

Comparative chromosome painting with mouse (Mus musculus, MMU) chromosome-specific DNA probes was performed for three Muridae species, the Indian soft-furred field rat (Millardia meltada), the spiny mouse (Acomys dimidiatus) and the harvest mouse (Micromys minutus). All probes except for the Y probe were successfully hybridized to the chromosomes of all species, and homologous chromosome segments between mouse and the three species were identified at the molecular level. Comparison of our data with the published data of six other genera (Mus, Rattus, Apodemus, Otomys, Rhabdomys and Cricetulus) of the Muridae suggested that the associations MMU1b/17a, 2b/13a, 5b/11a, 7/19, 10b/17b, 10c/17c, 11b/16a, 12/17d and 13b/15, and the single painted chromosomes and chromosome segments MMU3, 4, 5a, 8a, 8b, 16b, 18 and X were probably contained by the ancestral karyotype of the Muridae, and have been strongly conserved throughout murid evolution.     

Structural and functional analysis of <Emphasis Type="Italic">araC</Emphasis> gene in <Emphasis Type="Italic">Yersinia pestis</Emphasis> of various origins

Structural and functional analyses of the araC gene, which is involved in regulation of expression of diagnostically important characteristics, such as arabinose fermentation in the plague microbe strain, were carried out. It was established that the reason for the lack of arabinose fermentation in the altaica and hissarica subspecies and strains of talassica groups is the presence of the insertion of a single nucleotide in the araC gene at position 773 bp. The strains of the basic, caucasia, and ulegeica subspecies do not contain this mutation in the araC gene, which correlates to their ability to ferment arabinose.     

Complicating infectious foci in patients with <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> or <Emphasis Type="Italic">Streptococcus</Emphasis> species bacteraemia

Complicating infectious foci resulting from haematogenous or local spread of microorganisms are observed frequently in patients with Staphylococcus aureus bacteraemia (SAB) or Streptococcus species bacteraemia (SSB). The aim of this study was to compare the epidemiology of complicating infectious foci during SAB and SSB in a university hospital in The Netherlands. The charts of all adult patients diagnosed with SAB or SSB (except for Streptococcus pneumoniae bacteraemia) from July 2002 until December 2004 were reviewed retrospectively. Overall, 180 immunocompetent patients were identified, 127 with SAB and 53 with SSB. The percentage of patients with complicating infectious foci (39% of SAB patients, 25% of SSB patients) did not differ significantly between the groups. Endocarditis and cerebral involvement, however, were significantly more common in the SSB group. Of all complicating infectious foci, 32% lacked guiding signs or symptoms and 10% were detected only at autopsy. Factors associated with the development of complicating infectious foci were a delay in treatment for more than 48 h after the onset of symptoms, community acquisition, persistently positive blood cultures, congenital heart disease, and the presence of foreign bodies or prosthetic valves. Infection-related mortality was 18% in SAB patients and 11% in SSB patients and was significantly higher in patients with complicating infectious foci (29 vs. 9%). In conclusion, complicating infectious foci develop in approximately one-third of all patients with SAB and SSB. An active approach that entails searching for the complicating infectious foci is warranted in these patients, because only two-thirds of complicated infectious foci have guiding symptoms or signs, and infection-related mortality is significantly increased in patients with complicating infectious foci compared to patients without these infections. Authors M.L.H. Cuijpers and F.J. Vos contributed equally to this work.     

Divergence within the marker region of the <Emphasis Type="Italic">groESL</Emphasis> operon in <Emphasis Type="Italic">Anaplasma phagocytophilum</Emphasis>

Anaplasma phagocytophilum is an obligate intracellular bacterial parasite in human and animal granulocytes. In Europe, A. phagocytophilum is transmitted by Ixodes ticks; Ixodes ricinus is the vector of the parasite in Poland. In terms of epidemiology, the identification of pathogens in ticks increasingly relies on molecular techniques. Polymerase chain reaction (PCR) with species-specific primers is a tool that allows the quick and accurate detection of pathogens in ticks, humans, or animals. DNA was extracted from the blood of Capreolus capreolus and Cervus elaphus, and amplified using the primers HS1/HS6 (external) and HS43/HSVR (internal). For sequencing, six samples from roe deer and two samples from red deer were selected, and the resulting sequences were submitted to GenBank (accession numbers DQ779568, DQ779567, EU157919, EU157920, EU157921, EU157922). These nucleotide sequences were compared with each other and five variants were distinguished in roe deer and one in red deer. A comparison of the sequences of the author’s database revealed 45 polymorphic sites of substitution character (76% transitions and 24% transversions). The homology tree revealed two groups, one with sequences only from roe deer, while the second with sequences isolated mainly from red deer, livestock animals, and humans. These strains of A. phagocytophilum are also present in Poland.