Antimicrobial drug-resistant Escherichia coli from humans and poultry products, Minnesota and Wisconsin, 2002-2004

Similarities were found between drug-resistant E. coli from humans and poultry products.

The food supply, including poultry products, may transmit antimicrobial drug–resistant Escherichia coli to humans. To assess this hypothesis, 931 geographically and temporally matched E. coli isolates from human volunteers (hospital inpatients and healthy vegetarians) and commercial poultry products (conventionally raised or raised without antimicrobial drugs) were tested by PCR for phylogenetic group (A, B1, B2, D) and 60 virulence genes associated with extraintestinal pathogenic E. coli. Isolates resistant to trimethoprim-sulfamethoxazole, quinolones, and extended-spectrum cephalosporins (n = 331) were compared with drug-susceptible isolates (n = 600) stratified by source. Phylogenetic and virulence markers of drug-susceptible human isolates differed considerably from those of human and poultry isolates. In contrast, drug-resistant human isolates were similar to poultry isolates, and drug-susceptible and drug-resistant poultry isolates were largely indistinguishable. Many drug-resistant human fecal E. coli isolates may originate from poultry, whereas drug-resistant poultry-source E. coli isolates likely originate from susceptible poultry-source precursors.

First-line treatment with single agent rituximab, followed by maintenance rituximab plus anti-idiotype Id-KLH active immunotherapy vaccine (FavId) in patients (pts) with low-grade non-Hodgkin lymphoma (NHL): Preliminary results of a phase II trial

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Background: Single agent rituximab produces a high response rate when used as first-line treatment, and maintenance rituximab prolongs remission duration. Active immunotherapy is a promising treatment approach, when administered following remission induction by initial therapy. In this phase II trial, we evaluate the feasibility, toxicity, and efficacy of administering concurrent maintenance rituximab plus Id-KLH vaccine in pts with low-grade NHL. Methods: Pts with previously untreated low-grade NHL (grade 1/2 follicular or SLL) who were judged to be candidates for single agent rituximab therapy were eligible. All pts had initial biopsy for production of the Id-KLH vaccine. All pts received rituximab 375mg/m2 IV, weekly × 4. Pts with CR/CRu, PR, or stable disease at 8 weeks proceeded with maintenance rituximab (standard 4 week courses at 6 month intervals for 3 courses) and Id-KLH vaccination (Id-KLH 1cc day 1; GMCSF 250μg SQ days 1–4) monthly × 8, beginning month 3, then every 2 months during the second year. Pts were monitored for response rate, progression- free survival, and toxicity. Results: To date, 36 of a planned 56 pts have been enrolled. Idiotype vaccine was successfully manufactured in 27 of 32 pts (84%), with 4 in production. Of the 27 pts for whom Id-KLH was successfully manufactured, 2 progressed during rituximab. 19 of 25 pts (14FL;5SLL) have had response determined after rituximab: 8 PR (42%), 11 stable (58%; 4 of 5 SLL). Pts have now received rituximab maintenance therapy plus Id-KLH for durations of 6 - 34 months. 6 of 19 pts (3 SLL) progressed at months 5, 6, 9, 9, 10, and 12, respectively. Treatment has been well tolerated, with no unusual toxicities observed. Rituximab-related hypotension and atrial fibrillation occurred in 1 pt. The most common Id-KLH related adverse event has been injection site reaction. Conclusions: Concurrent maintenance therapy with rituximab plus Id-KLH is safe and well tolerated. At present, 6 of 25 pts (24%) have progressed (including 3 of the 5 SLL pts) with a median followup of 19 months. This trial is continuing.

No significant financial relationships to disclose.

Phase II trial of a 10-epitope CTL vaccine, EP-2101, in metastatic NSCLC patients

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Background: The 10-peptide EP-2101 vaccine is designed to induce multi-specific CTL responses against epitopes in CEA, p53, HER-2/neu and MAGE 2/3. Seven epitopes are modified for enhanced MHC binding or heteroclitic T-cell activation including the previously described CAP1–6D heteroclitic analog and 2 epitopes are native wild-type (WT) sequences. Also included is the helper epitope PADRE. We report here immunogenicity results from a Phase II trial of the EP-2101 vaccine. Methods: 66 HLA-A2+ good performance patients with Stage IIIB/IV NSCLC were enrolled. Patients received 6 induction doses (0.5 mg/epitope) q3 wks followed by maintenance treatments at 2–3 month intervals. Endpoints included survival and induction of immune responses. CTL responses in peripheral blood MNC were measured after a 10 day in vitro stimulation with peptide followed by an IFNγ ELISPOT assay. Results: 33 patients completed induction and the first 11 patients were monitored for CTL against all vaccine epitopes. Seven of 11 patients generated responses against ≥ 4 epitopes after 3 and 6 vaccine doses and 8 patients generated CTL against ≥ 3 WT vaccine epitopes and WT sequences of vaccine analogs. Responses ranged between 10–50 spots/5x10e4 cells with stronger responses of >100 spots observed. All 9 vaccine epitopes were immunogenic in at least 1 patient. CTL responses against epitopes were maintained at Wk 30 and/or Month 9 in 7 of 8 patients. At Month 12, 2 of 4 patients also had detectable CTL against the vaccine. The 22 remaining patients were monitored against 5 representative vaccine epitopes. 13 of these patients generated CTL responses to ≥ 2 epitopes and 7 patients generated responses to ≥ 3 epitopes. Th-cell responses against PADRE measured with a direct IFNγ ELISPOT assay were observed in 18 of the 33 patients tested. Toxicities attributable to vaccine were mild and consisted mostly of injection site reactions. Follow-up for survival is ongoing. Conclusions: The peptide vaccine EP-2101 is well-tolerated and induces broadly-specific CTL responses in metastatic NSCLC patients.

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Creatine supplementation in Parkinson disease: a placebo-controlled randomized pilot trial

Mitochondrial dysfunction plays a major role in the pathogenesis of Parkinson disease (PD). Creatine (Cr) is an ergogenic compound that exerts neuroprotective effects in animal models of PD. We conducted a 2-year placebo-controlled randomized clinical trial on the effect of Cr in 60 patients with PD. Cr improved patient mood and led to a smaller dose increase of dopaminergic therapy but had no effect on overall Unified Parkinson's Disease Rating Scale scores or dopamine transporter SPECT.

Growth and nutritive quality of Poa pratensis as influenced by ozone and competition

Interspecific plant competition has been hypothesized to alter effects of early-season ozone (O3) stress. A phytometer-based approach was utilized to investigate O3 effects on growth and nutritive quality of Poa pratensis grown in monoculture and in mixed cultures with four competitor-plant species (Anthoxanthum odoratum, Achillea millefolium, Rumex acetosa and Veronica chamaedrys). Mesocosms were exposed during April/May 2000-2002 to charcoal-filtered air+25 ppb O3 (control) or non-filtered air+50 ppb O3 (elevated O3). Biomass production was not affected by O3, but foliar injury symptoms were observed in May 2002. Early-season O3 exposure decreased relative food value of P. pratensis by an average of 8%, which is sufficient to have nutritional implications for its utilization by herbivores. However, forage quality response to O3 was not changed by interspecific competition. Lack of injury and nutritive quality response in P. pratensis harvested in September may reflect recovery from early-season O3 exposure.

Pathologic and immunohistochemical findings in goshawks (Accipiter gentilis) and great horned owls (Bubo virginianus) naturally infected with West Nile virus

The carcasses of 25 great horned owls and 12 goshawks were investigated for West Nile virus (WNV) infection by immunohistochemistry (IHC) performed on various organs, including brain, spinal cord, heart, kidney, eye, bone marrow, spleen, liver, lungs, pancreas, intestine, and proventriculus, using a WNV-antigen-specific monoclonal antibody and by WNV-specific reverse transcriptase-polymerase chain reaction (RT-PCR), performed on fresh brain tissue only. WNV infection was diagnosed by IHC in all owls and all goshawks. WNV-specific RT-PCR amplified WNV-RNA in the brain of all goshawks but only 12 owls (48%). Cachexia was a common macroscopic finding associated with WNV infection in owls (76%). Myocarditis was occasionally macroscopically evident in goshawks (33%). Microscopically, inflammatory lesions, including lymphoplasmacytic and histiocytic encephalitis, myocarditis, endophthalmitis, and pancreatitis were present in both species but were more common and more severe in goshawks than in owls. The most characteristic brain lesion in owls was the formation of glial nodules, in particular in the molecular layer of the cerebellum, while encephalitis affecting the periventricular parenchyma of the cerebral cortex was common in the goshawks. In owls, WNV-antigen-positive cells were present usually only in very small numbers per organ. Kidney (80%), heart (39%), and cerebellum (37%) were the organs that most commonly contained WNV antigen in owls. WNV antigen was frequently widely distributed in the organs of infected goshawks, with increased amounts of WNV antigen in the heart and the cerebrum. Spleen (75%), cerebellum (66%), heart (58%), cerebrum (58%), and eye (50%) were often WNV-antigen positive in goshawks. In contrast with the goshawks, WNV antigen was not present in cerebral and retinal neurons of owls. WNV infection appears to be capable of causing fatal disease in great horned owls and goshawks. However, the distribution and severity of histologic lesions, the antigen distribution in the various organs, and the amount of antigen varied among both species. Therefore, the diagnostician may choose organs for histology and immunohistochemistry as well as RT-PCR depending on the investigated species in order to avoid false-negative results.

Transdermal delivery from a lipid sponge phase--iontophoretic and passive transport in vitro of 5-aminolevulinic acid and its methyl ester

The hydrochloride salts of 5-aminolevulinic acid (ALA) and its methyl ester (m-ALA), respectively, were dissolved in a lipid sponge phase comprising monoolein, propylene glycol and aqueous buffer at concentrations of approximately 0.25% and 16% w/w m-ALA. The iontophoretic and passive delivery of ALA and m-ALA from this formulation through porcine skin in vitro were measured and compared to formulations used in clinical practice, 20% w/w ALA in Unguentum M and Metvix (a cream containing 16% w/w m-ALA). A sponge phase with 16% w/w m-ALA showed a higher passive flux (approximately 140 nmol cm(-2) h(-1) at 5 h) but a lower iontophoretic flux (approximately 800 nmol cm(-2) h(-1) at 5 h) compared to the clinically used products but the differences are hardly significant due to large standard deviations. ALA and m-ALA in sponge phase formulation showed iontophoretic fluxes in the range 80-100 nmol cm(-2) h(-1) at 3 h, i.e. values comparable to the passive fluxes from the more concentrated vehicles. The results demonstrate that the lipid sponge phase, a thermodynamically stable liquid with amphiphilic character, may have potential as a transdermal drug delivery vehicle.

Pathologic findings in red-tailed hawks (Buteo jamaicensis) and Cooper's hawks (Accipiter cooper) naturally infected with West Nile virus

Carcasses of 13 red-tailed hawks (RTHAs) and 11 Cooper's hawks (COHAs) were tested for West Nile virus (WNV) using WNV-specific reverse transcriptase-polymerase chain reaction (RT-PCR) on fresh brain tissue and WNV-specific immunohistochemistry (IHC) on various organs. Ten COHAs (91%) and 11 RTHAs (85%) were positive for WNV RNA by RT-PCR. All 11 COHAs (100%) and 10 RTHAs (77%) were positive for WNV antigen by IHC. A triad of inflammatory lesions, including chronic lymphoplasmacytic and histiocytic encephalitis, endophthalmitis, and myocarditis, was common in both species. In COHAs, the heart (54%), cerebrum (50%), and eye (45%) were the organs that most commonly contained WNV antigen. The amount of WNV antigen was usually small. In RTHAs, the kidney (38%), cerebrum (38%), cerebellum (38%), and eye (36%) were the organs most commonly containing WNV antigen. Unlike COHAs, larger amounts of WNV antigen were present in the cerebrum of RTHAs. WNV antigen was detected in similar cell populations in both species, including neurons of brain, spinal cord, and retina, pigmented epithelial cells of the retina, epithelial cells of renal medullary tubules, cardiomyocytes, endothelial cells and smooth muscle cells of arteries, dendritic cells of splenic lymph follicles, exocrine pancreatic cells, adrenal cells, and keratinocytes of the skin. The study presents strong evidence that WNV can cause a chronic fatal disease in RTHAs and COHAs. The lesion distribution of WNV infection in both species is variable, but inflammatory lesions are common, and a triad of lesions including encephalitis, myocarditis, and endophthalmitis is indicative of WNV infection in both species.

Pathological and immunohistochemical findings in American crows (Corvus brachyrhynchos) naturally infected with West Nile virus

Twenty-one American crows were identified as being West Nile virus (WNV) infected by WNV-specific reverse transcriptase-polymerase chain reaction (RT-PCR) performed on fresh brain tissue (cerebrum and cerebellum of 16 crows) or by WNV-specific immunohistochemistry of various organs (21 crows). Consistent gross lesions attributable to WNV infection were not detected. Common histological lesions included necrosis of spleen and bone marrow. West Nile virus antigen was consistently detected in heart and kidney (100%). In addition, bone marrow (92%), duodenum (89%), proventriculus (87%), liver (86%), lung (85%), spleen (80%), pancreas (61%), and brain (45%) contained WNV antigen-positive cells. Infected cells included cardiomyocytes; neurons; endothelial cells and vascular smooth muscle cells; hematopoietic cells of bone marrow; and macrophages of spleen, liver (Kupffer cells), and lungs. Epithelial cells of renal tubules, duodenum, pancreas, and proventriculus were also infected. The diagnostic histopathologist should consider WNV infection in crows in the absence of any inflammatory lesions. Immunohistochemistry of heart and kidney is as reliable in detecting WNV infection in American crows as RT-PCR of fresh brain tissue.

Prior antimicrobial agent use increases the risk of sporadic infections with multidrug-resistant Salmonella enterica serotype Typhimurium: a FoodNet case-control study, 1996-1997

Several strains of multidrug-resistant (MDR) Salmonella serotype Typhimurium, including MDR S. Typhimurium definitive type 104, cause almost 10% of Salmonella infections among humans in the United States. To determine the risk factors for acquiring sporadic MDR S. Typhimurium infection, we conducted a population-based, case-control study using data from the Foodborne Diseases Active Surveillance Network (FoodNet) during 1996-1997. S. Typhimurium isolates from 5 FoodNet surveillance areas (California, Connecticut, Georgia, Minnesota, and Oregon) were tested for antimicrobial resistance and phage typing. Telephone interviews were conducted with ill persons and matched control subjects. Compared with both control subjects and patients infected with pansensitive strains of S. Typhimurium, patients with MDR S. Typhimurium infection were significantly more likely to have received an antimicrobial agent, particularly an agent to which the Salmonella isolate was resistant, during the 4 weeks preceding illness onset. Prudent antimicrobial agent use among humans and among veterinarians and food-animal producers is necessary to reduce the burden of drug-resistant salmonellosis in humans.

Zoonotic infections in travelers to the tropics

Infections that normally occur in animal hosts, zoonoses are transmitted occasionally between animals and humans. Zoonoses occur worldwide, and the traveler may engage in activities increasing the risk of acquiring these otherwise rare infections. This article reviews selected zoonoses in the context of travel to the tropics.

Development of a closed-system process for clinical-scale generation of DCs: evaluation of two monocyte-enrichment methods and two culture containers

BACKGROUND

Clinical immunotherapy trials using DCs depend on large-scale methods for DC generation that fulfil current good manufacturing practice requirements. Our goal was to develop data on two variables, monocyte-enrichment method and culture container, which could be used to design a closed-system process for ex vivo generation of immature DCs.

METHODS

Mononuclear cells were collected by leukapheresis and enriched for monocytes by either counterflow centrifugal elutriation, or immunomagnetic selection using Isolex, an automated closed-system device. Monocytes were cultured for 7 days in serum-free medium with GM-CSF and IL-4, using either plastic flasks or gas-permeable Stericell bags. Monocytes and cultured DCs were evaluated for yield, flow cytometric phenotype, and in vitro function in MLR, and autologous recall responses to tetanus toxoid and influenza virus.

RESULTS

Enriched monocyte products from elutriation and immunomagnetic selection were equivalent in yield and purity, and were capable of generating immature DCs in either flasks or bags. DCs from all four culture conditions were equivalent in yield, phenotype, and in vitro function. Mean DC yield was 67-80% per seeding monocyte, and 11-13% per starting mononuclear cell (MNC). A leukapheresis product containing 5 x 10(9) MNCs processed by this method could therefore yield approximately 5 x 10(8) immature DCs.

DISCUSSION

In this manufacturing process, the Isolex system was equivalent to elutriation, and Stericell bags were equivalent to flasks. Together, the Isolex system and Stericell bags can be incorporated into a closed-system process to generate immature DCs.

CT and diffusion-weighted MR imaging in randomized order: diffusion-weighted imaging results in higher accuracy and lower interrater variability in the diagnosis of hyperacute ischemic stroke

BACKGROUND AND PURPOSE

Diffusion-weighted MRI (DWI) has become a commonly used imaging modality in stroke centers. The value of this method as a routine procedure is still being discussed. In previous studies, CT was always performed before DWI. Therefore, infarct progression could be a reason for the better result in DWI.

METHODS

All hyperacute (<6 hours) stroke patients admitted to our emergency department with a National Institutes of Health Stroke Scale (NIHSS) score >3 were prospectively randomized for the order in which CT and MRI were performed. Five stroke experts and 4 residents blinded to clinical data judged stroke signs and lesion size on the images. To determine the interrater variability, we calculated kappa values for both rating groups.

RESULTS

A total of 50 patients with ischemic stroke and 4 patients with transient symptoms of acute stroke (median NIHSS score, 11; range, 3 to 27) were analyzed. Of the 50 patients, 55% were examined with DWI first. The mean delay from symptom onset until CT was 180 minutes; that from symptom onset until DWI was 189 minutes. The mean delay between DWI and CT was 30 minutes. The sensitivity of infarct detection by the experts was significantly better when based on DWI (CT/DWI, 61/91%). Accuracy was 91% when based on DWI (CT, 61%). Interrater variability of lesion detection was also significantly better for DWI (CT/DWI, kappa=0.51/0.84). The assessment of lesion extent was less homogeneous on CT (CT/DWI, kappa=0.38/0.62). The differences between the 2 modalities were stronger in the residents' ratings (CT/DWI: sensitivity, 46/81%; kappa=0.38/0.76).

CONCLUSIONS

CT and DWI performed with the same delay after onset of ischemic stroke resulted in significant differences in diagnostic accuracy. DWI gives good interrater homogeneity and has a substantially better sensitivity and accuracy than CT even if the raters have limited experience.

Downregulation of beta2-microglobulin in human cord blood somatic stem cells after transplantation into livers of SCID-mice: an escape mechanism of stem cells?

Adherently growing, non-hematopoietic somatic stem cells isolated from human cord blood were stained with the fluorescent dye PKH26 and transplanted into livers of SCID-mice to examine a possible cell fate transition. Already 7 days after transplantation stem cells were well integrated into the liver tissue. Human albumin that was not expressed by the stem cells before transplantation was detectable in the host's livers after injection of cord blood stem cells. Human alpha1-antitrypsin was detectable in stem cells already before transplantation and remained positive in the mouse liver. The most interesting observation in this study was the downregulation of human beta2-microglobulin (beta2M) in the stem cells after transplantation: beta2M is expressed constitutively in our cord blood stem cells. However, beta2M was no longer detectable by RT-PCR in all tissues where human albumin and alpha1-antitrypsin were expressed after stem cell transplantation. beta2M is known to participate as an integral part of the major histocompatibility complex. Absence of beta2M makes the residual heavy chain inactive as an antigen. Thus, downregulation of beta2M may represent an escape mechanism from killer-T cells and may be a molecular mechanism explaining the recently described "immunological blindness" [37] of stem cells. In contrast to the results obtained after direct injection of stem cells as a suspension, no consistent downregulation of beta2M was observed after transplantation of stem cells encapsulated in alginate beads to generate a compartment where stem cells are protected from the host's natural killer cells. No expression of human genes was observed after transplantation of human cord blood derived mononuclear cells (MNC) that were used as a negative control. In conclusion, we have shown that human cord blood somatic stem cells survive and are reprogrammed after transplantation into mouse livers, although a complete transdifferentiation to hepatocytes did not occur within 7 days, since some marker genes (GATA4 and alpha-fetoprotein) were still negative. Switching off expression of beta2M may be part of an intriguing and novel mechanism explaining why stem cells escape the host's immune system.

Identification and characterization of Magmas, a novel mitochondria-associated protein involved in granulocyte-macrophage colony-stimulating factor signal transduction

OBJECTIVE

The aim of this study was to identify granulocyte-macrophage colony-stimulating factor (GM-CSF) responsive genes.

MATERIALS AND METHODS

Potential GM-CSF responsive genes were identified by comparing the mRNA expression pattern of the murine myeloid cell line PGMD1 grown in either interleukin-3 (IL-3) or GM-CSF by differential display. Human and murine cDNA clones of one of the bands having increased expression in GM-CSF were isolated. mRNA expression of the gene was examined by Northern blot. Immunohistochemistry and studies with a green fluorescent fusion protein were used to determine its intracellular location. Growth factor-stimulated proliferation of PGMD1 cells transfected with constitutively expressed sense and anti-sense cDNA constructs of the gene was measured by 3H-thymidine incorporation.

RESULTS

A gene, named Magmas (mitochondria-associated granulocyte macrophage CSF signaling molecule), was shown to be rapidly induced when cells were switched from IL-3 to GM-CSF. Analysis of the amino acid sequence of Magmas showed it contained a mitochondrial signal peptide, but not any other known functional domains. The human and murine clones encode nearly identical 13-kDa proteins that localized to the mitochondria. Magmas mRNA expression was observed in all tissues examined. PGMD1 cells that overexpressed Magmas proliferated similarly to untransfected cells when cultured in IL-3 or GM-CSF. In contrast, cells with reduced protein levels grew normally in IL-3, but had impaired proliferation in GM-CSF.

CONCLUSION

Magmas is a mitochondrial protein involved in GM-CSF signal transduction.