Yersinia enterocolitica infection with multiple liver abscesses uncovering a primary hemochromatosis

A 60-year-old man, although treated with antibiotics, suffered from a severe pyrexial illness of unknown origin, weight loss and intermittent abdominal pain. There was no history of diarrhea or common infections. Computed tomography and ultrasound imaging showed uncharacteristic multiple small lesions of the entire liver parenchyma. These lesions were histologically pyogenic abscesses. In addition, an unexpected, pronounced accumulation of iron pigment in hepatocytes and second degree fibrotic changes of the liver were detected. Serum iron and serum transferrin were low, but serum ferritin concentration and transferrin saturation were increased to the maximum. The demonstration of the cysteine-282-tyrosine mutation confirmed underlying primary hemochromatosis. Bacteriological cultures of the abscess material yielded Yersinia enterocolitica serotype O:3, while stool and blood cultures were negative. Antibiotic therapy with piperacillin/tazobactam and tobramycin was successful within a few days. A repeat CT scan and ultrasound imaging demonstrated complete regression of the pathologic liver morphology. The patient was discharged and treated with an orally administered fluoroquinolone for an additional 6 months. After this time the patient had no morphological residues of the infection except one enlarged lymph node near the portal vein but still was so weak that he was unable to work again. In conclusion, severe septic forms of yersiniosis are mainly found in patients with iron overload, due to a handicapped iron metabolism of the Yersinia bacteria. Mortality is high despite treatment.

Plastidic metabolite transporters and their physiological functions in the inducible crassulacean acid metabolism plant Mesembryanthemum crystallinum

The inducible crassulacean acid metabolism (CAM) plant Mesembryanthemum crystallinum accumulates malic acid during the night and converts it to starch during the day via a pathway that, because it is located in different subcellular compartments, depends on specific metabolite transport across membranes. The chloroplast glucose transporter (pGlcT) and three members of the phosphate translocator (PT) family were isolated. After induction of CAM, transcript amounts of the phosphoenolpyruvate (PEP) phosphate translocator (PPT) and the glucose-6-phosphate (Glc6P) phosphate translocator (GPT) genes were increased drastically, while triose phosphate (TP) phosphate translocator (TPT) and the pGlcT transcripts remained unchanged. PPT- and GPT-specific transcripts and transporter activities exhibited a pronounced diurnal variation, displaying the highest amplitude in the light. pGlcT transcripts were elevated towards the end of the light period and at the beginning of the dark period. These findings, combined with diurnal variations of enzyme activities and metabolite contents, helped to elucidate the roles of the PPT, GPT, TPT and pGlcT in CAM. The main function of the PPT is the daytime export from the stroma of PEP generated by pyruvate orthophosphate:dikinase (PPDK). The increased transport activity of GPT in the light suggests a higher requirement for Glc6P import for starch synthesis rather than starch mobilization. Most likely, Glc6P rather than 3-phosphoglycerate or triose phosphates is the main substrate for daytime starch biosynthesis in M. crystallinum plants in which CAM has been induced (CAM-induced), similar to non-green plastids. In the dark, starch is mobilized both phosphorylytically and amylolytically and the products are exported by the GPT, TPT and pGlcT. The transport activities of all three phosphate translocators and the transcript amounts of the pGlcT adapt to changing transport requirements in order to maintain high metabolic fluxes during the diurnal CAM cycle.

Protein S-100beta in brain and serum after deep hypothermic circulatory arrest in rabbits: relationship to perivascular astrocytic swelling

The aim of this study was to evaluate the relationship between the kinetic patterns of the protein S-100beta, an astroglial cell marker, and its immunohistochemical expression in the brain in rabbits that underwent cardiopulmonary bypass with deep hypothermic circulatory arrest. Fourteen New Zealand rabbits (weight, 3.1+/-0.25 kg) were anaesthetised, intubated and mechanically ventilated. Four animals were not connected to the cardiopulmonary bypass and served as controls. Ten animals were perfused according to a uniform protocol. After systemic cooling, deep hypothermic circulatory arrest was induced for 60 minutes. After reperfusion and rewarming, the animals were weaned from bypass and sacrificed. In the brain, astrocyte reactivity for S-100beta was evaluated immunocytochemically (DPC Immustain) and the serum concentrations of S-100beta were analysed using a commercially available immunoluminometric kit (Byk-Sangtec, Dietzenbach, Germany). In all experimental animals a significant increase of the serum concentration of the protein S-100beta was found immediately after reperfusion and the termination of cardiopulmonary bypass. In comparison with the control animals, increased staining of S-100beta was found in the astroglial cells and swollen astrocytic end-feet in the perivascular regions. There were fewer signs of neuronal cell injury of neurones in the hippocampus structure. In conclusion, astrocytic activation and S-100beta overexpression seems to precede the neurodegeneration following deep hypothermic circulatory arrest. The marked perivascular cell swelling may support the assumption of reperfusion injury of the astroglial cell complex that forms the blood-brain barrier, which may be indicative of the source of the released S-100beta into the blood stream.

The effect of continuous treatment with sodium nitroprusside on the serum kinetics of the brain marker protein S-100beta in neonates undergoing corrective cardiac surgery by means of hypothermic cardiopulmonary bypass

Neonates who undergo cardiac surgery of d-transposition of the great arteries by means of hypothermic cardiopulmonary bypass (CPB) represent a group at increased risk to develop brain injury and altered psychomotor development in early life. Measurement of protein S-100beta, an astrocytic calcium binding protein, in serum may provide information on transient astroglial cell activation and disintegration of the related blood-brain barrier due to oxidative stress during and after CPB. Conflicting results have been reported that concern the neuroprotective effect of the NO liberator sodium nitroprusside (SNP) in vitro. We evaluated the effect of continuous treatment with SNP on the serum kinetics of S-100beta in infants and children after corrective cardiac surgery. The data on 25 neonates treated intraoperatively and postoperatively and 28 without treatment were analyzed. SNP was infused (1-5 microg/kg body weight/minute depending on the haemodynamic status) after the induction of anesthesia, and during and after the termination of CPB for 2 days. Serum concentrations of S-100beta were analyzed by the use of a commercially available immunoluminometric kit (Byk-Sangtec, Dietzenbach, Germany). There were no significant differences in the bypass data between the SNP-treated and non-treated group. In comparison to the pre-bypass values, a similar increase in the concentration of protein S-100beta was found 2 hours after the termination of CPB in the SNP-treated and non-treated neonates, which decreased over the subsequent 48 postoperative hours. However, significantly lower post-bypass serum levels of S-100beta were found in the SNP-treated group after 24 hours (p = 0.0009) and 48 hours (p = 0.04) of treatment. In conclusion, the significant elevation of serum levels of protein S-100beta may indicate increased astroglial cell reactivity and increased passage into the blood stream. Longer-lasting treatment with NO liberator SNP seemed to decrease the release of S-100beta into the blood stream and may have delayed protection on the astroglial cells. The neurological significance of such an observation, however, should be evaluated in further follow-up studies, which need to include additional neurophysiological and neurodevelopmental tests.

High-pathogenicity island of Yersinia pestis in enterobacteriaceae isolated from blood cultures and urine samples: prevalence and functional expression

Production of the siderophore yersiniabactin is associated with virulence in Yersinia species. The genes for biosynthesis and uptake of yersiniabactin are located on a high-pathogenicity island (HPI). The distribution and functioning of the Yersinia HPI were assessed in different Enterobacteriaceae strains isolated from blood cultures and urine samples. In total, 550 clinical isolates from 10 Enterobacteriaceae species were investigated by polymerase chain reaction and DNA hybridization. The Yersinia HPI was most prevalent in Escherichia coli (overall prevalence, 72.3%) and, to a lesser extent, in Klebsiella oxytoca (58.3%), Citrobacter species (25%), Klebsiella pneumonia (17.7%), and Enterobacter species (12.2%). The production of the siderophore yersiniabactin was also demonstrated in these HPI-positive strains by use of a reporter gene bioassay. These findings indicate that the HPI of Yersinia is distributed and functions in clinical specimens of different Enterobacteriaceae species.

Organization and expression of rat Tspy

We have isolated both a full-length rat Tspy cDNA from testicular mRNA by rapid amplification of cDNA ends (RACE) and RT-PCR and a full-length rat Tspy gene from genomic DNA by PCR. In contrast to the mouse, where Tspy is present in a single copy and is apparently functionless, and to man and cattle, where TSPY is organized in a moderately repetitive cluster, the rat Tspy locus apparently consists of one complete functional and one truncated, probably nonfunctional, copy, coherently localized on Yp, as revealed by FISH analysis.

Culture independent and rapid identification of bacterial pathogens in necrotising fasciitis and streptococcal toxic shock syndrome by fluorescence in situ hybridisation

Fluorescence in situ hybridisation (FISH) targeted to ribosomal RNA is well established for studies in environmental microbiology. Initial applications of this technique in the field of medical microbiology showed that FISH is also a suitable means for the rapid, reliable and cultivation-independent identification of bacterial pathogens. In particular, for infectious diseases that follow a fulminant live-threatening course, such as sepsis or necrotising fasciitis (NF), a fast and reliable detection technique is of great importance. This study describes the development of an rRNA-targeted oligonucleotide set covering more than 95% of the pathogens associated with NF. These probes were tested with a broad collection of target and non-target organisms and found to be highly specific. Subsequently, the FISH approach was applied for the direct detection of bacterial pathogens in clinical samples. Two cases of NF and one case of streptococcal toxic shock syndrome (STSS) were analysed. FISH correctly identified almost all pathogens present in the samples examined within 2-3 h. However, Proteus mirabilis, which was identified in one sample by conventional methods was detected as a rod-shaped bacteria but could not be identified by FISH, since no specific probe was available for this particular organism. In contrast, identification of pathogens in these samples by conventional laboratory methods took 48-72 h. Furthermore, in one patient with pre-sampling antimicrobial therapy bacteria could not be grown from any of the samples. FISH unequivocally revealed the presence of Streptococcus pyogenes in affected tissue samples from this patient. In an experimental setting we demonstrated that FISH readily identifies S. pyogenes cells rendered non-cultivable by antibiotic treatment.

Conjugation of hydroxyethyl starch to desferrioxamine (DFO) modulates the dual role of DFO in Yersinia enterocolitica infection

The iron chelator desferrioxamine (DFO) B is widely used in the therapy of patients with iron overload. As a side effect, DFO may favor the occurrence of fulminant Yersinia infections. Previous work from our laboratory showed that this might be due to a dual role of DFO: growth promotion of the pathogen and immunosuppression of the host. In this study, we sought to determine whether conjugation of DFO to hydroxyethyl starch (HES-DFO) may prevent exacerbation of Yersinia infection in mice. We found HES-DFO to promote neither growth of Yersinia enterocolitica nor mitogen-induced T-cell proliferation and gamma interferon production by T cells in vitro. Nevertheless, in vivo HES-DFO promoted growth of Y. enterocolitica possibly due to cleavage of HES and release of DFO. The pretreatment of mice with DFO resulted in death of all mice 2 to 5 days after application of a normally sublethal inoculum of Y. enterocolitica, while none of the mice pretreated with HES-DFO died within the first 7 days postinfection. However, some of the HES-DFO-treated mice died 8 to 14 days postinfection. Thus, due to the delayed in vivo effect HES-DFO failed to trigger Yersinia-induced septic shock, which accounts for early mortality in DFO-associated septicemia. Moreover, our data suggest that DFO needs to be taken up by host cells in order to exert its immunosuppressive action. These results strongly suggest that HES-DFO might be a favorable drug with fewer side effects than DFO in terms of DFO-promoted fulminant infections.

Signalling pathways in vascular endothelium activated by shear stress: relevance to atherosclerosis

Major advances in our understanding of how endothelial cells sense and respond to haemodynamic forces and, more specifically, to fluid shear stress have been achieved during the past 3 years. These include definition of potential shear stress receptors and multiple signalling pathways that mediate shear stress regulation of gene expression. A few studies have also pointed to the unique effects of complex shear stress on endothelial activation, thus leading to better understanding of the mechanisms that lead to the development of atherosclerosis.

Silencing of the Y-chromosomal gene tspy during murine evolution

We have studied the process of tspy gene silencing in murine evolution. We have isolated functional tspy sequences from Apodemus agrarius, A. sylvaticus, A. flavicollis, and Mus platythrix (subgenus Pyromys) and nonfunctional tspy sequences from species of the subgenus Mus. We present two alternative models as to how tspy may have lost its function in the murine lineage.

Internalization of extraintestinal Escherichia coli O18 strains by epithelial cells is modulated by EGF, insulin, and effectors of transmembrane signal transduction

Adhesion to and internalization into host cells is an essential step in the pathogenesis of various bacterial infections. Here we investigated the effects of growth factors on the internalization of Escherichia coli O18 strains isolated from patients with urinary tract infection (UTI) by human epithelial cells. A dramatic increase in the uptake of Escherichia coli was observed after treatment of epithelial cells with epidermal growth factor (EGF) and to a lower extent with insulin. EGF-dependent internalization can be suppressed by tyrosine kinase inhibitors suggesting an involvement of the receptor tyrosine kinases in the regulation of the endocytotic process. Inhibitors of phospholipase A2, lipoxygenase, and cyclooxygenase significantly decreased internalization of bacteria induced by EGF. Finally, the specific inhibitor of PI 3-kinases Wortmannin was shown to suppress completely the EGF-independent internalization. The data of this analysis indicate the involvement of several signaling paths in bacterial internalization of uropathogenic Escherichia coli O18 strains and contribute to the comprehension of the pathogenesis of recurrent UTI.

They were different and few: an Australian study of midwives' attitudes to research and computerised research findings

This study sought to determine factors influencing the utilisation of research findings by Australian midwives before and after exposure to an on-line research database within their practice setting. The setting was a large maternity hospital in South Australia and data were collected via pre and post intervention questionnaires. 14 midwives from the Delivery Suite and Birth Centre of this hospital participated in the study. Midwives showed an increased receptivity to the concept of computerised research findings after exposure to the database. They rated research as highly important to providing quality midwifery care and for the midwifery profession, and saw midwives as the key players in maternity care research. These findings are not in keeping with previous research--largely accounted for, we believe, by the particular, and small number of, midwives who volunteered to participate in the study (24% of those invited).

Local hopping of IS3 elements into the A+T-rich part of the high-pathogenicity island in Yersinia enterocolitica 1B, O:8

The high-pathogenicity island (Yen HPI) of Yersinia enterocolitica biogroup (BG) 1B strains is associated with mouse virulence. Three repeated sequences are clustered on the A+T-rich part of the Yen HPI downstream of the fyuA yersiniabactin receptor gene in Y. enterocolitica O:8 strains WA-314 and 8081. In addition to IS1328 and IS1400, the RS3 repeated sequence consists of a novel insertion sequence, IS1329, inserted into the remnants of IS1222. This partial IS retains both 44-bp inverted terminal repeats (ITRs) of IS1222 but has suffered deletions of different sizes in strains WA-314 and 8081. IS1329 is 1243-bp long, carries 25-bp imperfect ITRs and two consecutive orfs capable to encode 110-amino acid (aa) and 249-aa proteins, respectively. IS1329 is present only in BG 1B Y. enterocolitica strains. Similarly to IS1400, IS1329 and IS1222 belong to the IS3 group of mobile elements and seem to have preference for the 'local hopping' into the A+T-rich part of the Yen HPI. These insertion sequences may be responsible for the imprecise deletions of the Yen HPI in strain WA-314.

A genomic island, termed high-pathogenicity island, is present in certain non-O157 Shiga toxin-producing Escherichia coli clonal lineages

Shiga toxin-producing Escherichia coli (STEC) strains cause a wide spectrum of diseases in humans. In this study, we tested 206 STEC strains isolated from patients for potential virulence genes including stx, eae, and enterohemorrhagic E. coli hly. In addition, all strains were examined for the presence of another genetic element, the high-pathogenicity island (HPI). The HPI was first described in pathogenic Yersinia species and encodes the pesticin receptor FyuA and the siderophore yersiniabactin. The HPI was found in the genome of distinct clonal lineages of STEC, including all 31 eae-positive O26:H11/H(-) strains and 7 of 12 eae-negative O128:H2/H(-) strains. In total, the HPI was found in 56 (27.2%) of 206 STEC strains. However, it was absent from the genome of all 37 O157:H7/H(-), 14 O111:H(-), 13 O103:H2, and 13 O145:H(-) STEC isolates, all of which were positive for eae. Polypeptides encoded by the fyuA gene located on the HPI could be detected by using immunoblot analysis in most of the HPI-positive STEC strains, suggesting the presence of a functional yersiniabactin system. The HPI in STEC was located next to the tRNA gene asnT. In contrast to the HPI of other pathogenic enterobacteria, the HPI of O26 STEC strains shows a deletion at its left junction, leading to a truncated integrase gene int. We conclude from this study that the Yersinia HPI is disseminated among certain clonal subgroups of STEC strains. The hypothesis that the HPI in STEC contributes to the fitness of the strains in certain ecological niches rather than to their pathogenic potential is discussed.

Characterization of the integration site of Yersinia high-pathogenicity island in Escherichia coli

The high-pathogenicity island (HPI) of virulent Yersiniae consists of (i) a functional core encoding for biosynthesis and uptake of the siderophore yersiniabactin and (ii) a 5- to 13-kb AT-rich region of unknown function. This Yersinia HPI has been shown to be widely distributed among different pathotypes of Escherichia coli. In this study, the insertion site of the HPI was defined in three different E. coli strains: The enteroaggregative E. coli (EAggEC) strain 17-2, the uropathogenic (UPEC) E. coli strain 536, and the probiotic E. coli DSM6601. We demonstrated that in all three E. coli isolates the HPI is associated with the asnT tRNA (5'-extremity) and truncated in the AT-rich region (3'-extremity) since the 17-bp direct repeat (DR) of the asn tRNA that flanks the HPI in Yersinia is missing in E. coli. Moreover, in comparison to the HPI-negative E. coli K-12 strain, a uniform deletion must have taken place in the E. coli chromosome adjacent to the 3'-border of the HPI.

Common and specific characteristics of the high-pathogenicity island of Yersinia enterocolitica

Yersinia pestis, Y. pseudotuberculosis O:1, and Y. enterocolitica biogroup 1B strains carry a high-pathogenicity island (HPI), which mediates biosynthesis and uptake of the siderophore yersiniabactin and a mouse-lethal phenotype. The HPI of Y. pestis and Y. pseudotuberculosis (Yps HPI) are highly conserved in sequence and organization, while the HPI of Y. enterocolitica (Yen HPI) differs significantly. The 43,393-bp Yen HPI sequence of Y. enterocolitica WA-C, serotype O:8, was completed and compared to that of the Yps HPI of Y. pseudotuberculosis PB1, serotype O:1A. A common GC-rich region (G+C content, 57.5 mol%) of 30.5 kb is conserved between yersinia strains. This region carries genes for yersiniabactin biosynthesis, regulation, and uptake and thus can be considered the functional "core" of the HPI. In contrast, the second part of the HPI is AT rich and completely different in two evolutionary lineages of the HPI, being 12.8 kb in the Yen HPI and 5.6 kb in the Yps HPI. The variable part acquired one IS100 element in the Yps HPI and accumulated four insertion elements, IS1328, IS1329, IS1400, and IS1222, in the Yen HPI. The insertion of a 125-bp ERIC sequence modifies the structure of the promoter of the ybtA yersiniabactin regulator in the Yen HPI. In contrast to the precise excision of the Yps HPI in Y. pseudotuberculosis, the Yen HPI suffers imprecise deletions. The Yen HPI is stably integrated in one of the three asn tRNA copies in Y. enterocolitica biogroup 1B (serotypes O:8, O:13, O:20, and O:21), probably due to inactivation of the putative integrase. The 17-bp duplications of the 3' end of the asnT RNA are present in both Yersinia spp. The HPI attachment site is unoccupied in nonpathogenic Y. enterocolitica NF-O, biogroup 1A, serotype O:5. The HPI of Yersinia is a composite and widely spread genomic element with a highly conserved yersiniabactin functional "core" and a divergently evolved variable part.

Ferric enterochelin transport in Yersinia enterocolitica: molecular and evolutionary aspects

Yersinia enterocolitica is well equipped for siderophore piracy, encompassing the utilization of siderophores such as ferrioxamine, ferrichrome, and ferrienterochelin. In this study, we report on the molecular and functional characterization of the Yersinia fep-fes gene cluster orthologous to the Escherichia coli ferrienterochelin transport genes (fepA, fepDGC, and fepB) and the esterase gene fes. In vitro transcription-translation analysis identified polypeptides of 30 and 35 kDa encoded by fepC and fes, respectively. A frameshift mutation within the fepA gene led to expression of a truncated polypeptide of 40 kDa. The fepD, fepG, and fes genes of Y. enterocolitica were shown to complement corresponding E. coli mutants. Insertional mutagenesis of fepD or fes genes abrogates enterochelin-supported growth of Y. enterocolitica on iron-chelated media. In contrast to E. coli, the fep-fes gene cluster in Y. enterocolitica consists solely of genes required for uptake and utilization of enterochelin (fep) and not of enterochelin synthesis genes such as entF. By Southern hybridization, fepDGC and fes sequences could be detected in Y. enterocolitica biotypes IB, IA, and II but not in biotype IV strains, Yersinia pestis, and Yersinia pseudotuberculosis strains. According to sequence alignment data and the coherent structure of the Yersinia fep-fes gene cluster, we suggest early genetic divergence of ferrienterochelin uptake determinants among species of the family Enterobacteriaceae.

Comparative in-vitro activity of levofloxacin, other fluoroquinolones, doxycycline and erythromycin against Ureaplasma urealyticum and Mycoplasma hominis

The susceptibility of 56 Ureaplasma urealyticum and 57 Mycoplasma hominis strains to levofloxacin, ofloxacin, ciprofloxacin, fleroxacin, doxycycline and erythromycin was determined by an agar dilution method. The reference strain used was M. hominis PG 21. Agar plates containing serial dilutions of antibiotics (range 0.03-16 mg/L), and control plates (without antibiotics) were inoculated with bacteria suspended in modified Shepard's broth using a multipoint inoculator. Levofloxacin showed greater activity against all U. urealyticum and M. hominis strains compared with all other antibiotics tested. The MIC90 values for U. urealyticum were as follows: levofloxacin, 1 mg/L; ofloxacin, 2 mg/L; ciprofloxacin, 4 mg/L; fleroxacin, 4 mg/L; doxycycline, 1 mg/L; erythromycin, 8 mg/L. The MIC90s for M. hominis were: levofloxacin, 1 mg/L; ofloxacin, 2 mg/L; ciprofloxacin, 4 mg/L; fleroxacin, 4 mg/L; doxycycline, 4 mg/L; erythromycin, > or = 16 mg/L. In conclusion, the results of this study suggest that levofloxacin may be useful in the treatment of mycoplasma genital infections.