Spread of ESBL-producing Escherichia coli in nursing home residents in Ireland and the Netherlands may reflect infrastructural differences.

A prevalence study in two nursing homes (one each in the Netherlands and Ireland) found four (11%) Dutch and six (9%) Irish residents colonized with 11 extended-spectrum beta-lactamase-producing Escherichia coli, 10 of which contained CTX-M-15. Four Dutch isolates, from three residents of the same ward, belonged to E. coli O25:H4, sequence type (ST) 131 and were part of the same cluster type by whole-genome sequencing. Four Irish residents on three different wards were colonized with an identical E. coli O89:H9, ST131, complex type 1478. Cross-transmission between three Irish wards may reflect differences in nursing home infrastructure, specifically communal areas and multi-bedded resident rooms.

Spatial clustering and livestock exposure as risk factor for community-acquired Clostridium difficile infection.

OBJECTIVES: Clostridium difficile infections (CDI) account for 1.5% of diarrhoeic episodes in patients attending a general practitioner in the Netherlands, but its sources are unknown. We searched for community clusters to recognize localized point sources of CDI. METHODS: Between October 2010 and February 2012, a community-based prospective nested case-control study was performed in three laboratories in the Netherlands with a study population of 2 810 830 people. Bernoulli spatial scan and space-time permutation models were used to detect spatial and/or temporal clusters of CDI. In addition, a multivariate conditional logistic regression model was constructed to test livestock exposure as a supposed risk factor in CDI patients without hospital admission within the previous 12 weeks (community-acquired (CA) CDI). RESULTS: In laboratories A, B and C, 1.3%, 1.8% and 2.1% of patients with diarrhoea tested positive for CDI, respectively. The mean age of CA-CDI patients (n = 124) was 49 years (standard deviation, 22.6); 64.5% were female. No spatial or temporal clusters of CDI cases were detected compared to C. difficile-negative diarrhoeic controls. Except for one false-positive signal, no spatiotemporal interaction amongst CDI cases was found. Livestock exposure was not related to CA-CDI (odds ratio, 0.99; 95% confidence interval, 0.44-2.24). Ten percent of CA-CDIs was caused by PCR ribotype 078, spatially dispersed throughout the study area. CONCLUSIONS: The absence of clusters of CDI cases in a community cohort of diarrhoeic patients suggests a lack of localized point sources of CDI in the living environment of these patients.

An outbreak of Clostridium difficile infections due to new PCR ribotype 826: epidemiologic and microbiologic analyses.

OBJECTIVES: To investigate an unusual outbreak of five patients with a total of eight episodes of a Clostridium difficile infection on a gastrointestinal surgical ward of a Dutch tertiary-care, university-affiliated hospital. METHODS: Clinical case investigations and laboratory analyses were performed. Laboratory analyses included PCR ribotyping, multiple-locus variable-number tandem repeat analysis typing, toxin typing, antimicrobial susceptibility testing and whole genome sequencing. RESULTS: The outbreak was associated with recurrent and severe disease in two of five patients. All episodes were due to a unique ribotype that was not recognized in the collection of an international network of reference laboratories and was assigned PCR ribotype 826. PCR ribotype 826 is a toxin A-, toxin B- and binary toxin-positive ribotype which according to molecular typing belongs to clade 5 and resembles the so-called hypervirulent ribotype 078. The presence of a clonal outbreak was confirmed by whole genome sequencing, yet the source of this newly identified ribotype remained unclear. CONCLUSIONS: This newly identified C. difficile PCR ribotype 826 is part of clade 5 and might also have increased virulence. The recognition of this outbreak highlights the need for ongoing C. difficile infection surveillance to monitor new circulating ribotypes with assumed increased virulence.

Molecular typing and antimicrobial susceptibility testing to six antimicrobials of Clostridium difficile isolates from three Czech hospitals in Eastern Bohemia in 2011-2012.

In 2011-2012, a survey was performed in three regional hospitals in the Czech Republic to determine the incidence of Clostridium difficile infections (CDIs) and to characterize bacterial isolates. C. difficile isolates were characterized by PCR ribotyping, toxin genes detection, multiple-locus variable-number tandem-repeat analysis (MLVA), and antimicrobial susceptibility testing to fidaxomicin, vancomycin, metronidazole, clindamycin, LFF571, and moxifloxacin using agar dilution method. The incidence of CDI in three studied hospitals was 145, 146, and 24 cases per 100,000 inhabitants in 2011 and 177, 258, and 67 cases per 100,000 inhabitants in 2012. A total of 64 isolates of C. difficile was available for molecular typing and antimicrobial susceptibility testing. 60.9% of the isolates were classified as ribotype 176. All 41 isolates of ribotypes 176 and 078 were positive for the presence of binary toxin genes. Ribotype 176 also carried 18-bp deletion in the regulatory gene tcdC. Tested isolates of C. difficile were fully susceptible to vancomycin and metronidazole, whereas 65.1% of the isolates were resistant to moxifloxacin. MLVA results indicated that isolates from three different hospitals were genetically related, suggesting transmission between healthcare facilities.

Whole genome sequencing reveals potential spread of Clostridium difficile between humans and farm animals in the Netherlands, 2002 to 2011.

Farm animals are a potential reservoir for human Clostridium difficile infection (CDI), particularly PCR ribotype 078 which is frequently found in animals and humans. Here, whole genome single-nucleotide polymorphism (SNP) analysis was used to study the evolutionary relatedness of C. difficile 078 isolated from humans and animals on Dutch pig farms. All sequenced genomes were surveyed for potential antimicrobial resistance determinants and linked to an antimicrobial resistance phenotype. We sequenced the whole genome of 65 C. difficile 078 isolates collected between 2002 and 2011 from pigs (n = 19), asymptomatic farmers (n = 15) and hospitalised patients (n = 31) in the Netherlands. The collection included 12 pairs of human and pig isolates from 2011 collected at 12 different pig farms. A mutation rate of 1.1 SNPs per genome per year was determined for C. difficile 078. Importantly, we demonstrate that farmers and pigs were colonised with identical (no SNP differences) and nearly identical (less than two SNP differences) C. difficile clones. Identical tetracycline and streptomycin resistance determinants were present in human and animal C. difficile 078 isolates. Our observation that farmers and pigs share identical C. difficile strains suggests transmission between these populations, although we cannot exclude the possibility of transmission from a common environmental source.

γδT cells elicited by CMV reactivation after allo-SCT cross-recognize CMV and leukemia.

Human cytomegalovirus (CMV) infections and relapse of disease remain major problems after allogeneic stem cell transplantation (allo-SCT), in particular in combination with CMV-negative donors or cordblood transplantations. Recent data suggest a paradoxical association between CMV reactivation after allo-SCT and reduced leukemic relapse. Given the potential of Vδ2-negative γδT cells to recognize CMV-infected cells and tumor cells, the molecular biology of distinct γδT-cell subsets expanding during CMV reactivation after allo-SCT was investigated. Vδ2(neg) γδT-cell expansions after CMV reactivation were observed not only with conventional but also cordblood donors. Expanded γδT cells were capable of recognizing both CMV-infected cells and primary leukemic blasts. CMV and leukemia reactivity were restricted to the same clonal population, whereas other Vδ2(neg) T cells interact with dendritic cells (DCs). Cloned Vδ1 T-cell receptors (TCRs) mediated leukemia reactivity and DC interactions, but surprisingly not CMV reactivity. Interestingly, CD8αα expression appeared to be a signature of γδT cells after CMV exposure. However, functionally, CD8αα was primarily important in combination with selected leukemia-reactive Vδ1 TCRs, demonstrating for the first time a co-stimulatory role of CD8αα for distinct γδTCRs. Based on these observations, we advocate the exploration of adoptive transfer of unmodified Vδ2(neg) γδT cells after allo-SCT to tackle CMV reactivation and residual leukemic blasts, as well as application of leukemia-reactive Vδ1 TCR-engineered T cells as alternative therapeutic tools.

Prognostic factors and outcome in relapsed multiple myeloma after nonmyeloablative allo-SCT: a single center experience.

For relapsed multiple myeloma (MM) patients, allo-SCT is a possible treatment option, but recent data obtained using a nonmyeloablative (NMA) conditioning regimen are scarce. We retrospectively collected data from 38 relapsed MM patients who received a NMA allo-SCT from October 2001 to January 2008. In total, 18 patients (48%) were transplanted using a matched unrelated donor. The median follow-up is 2.3 years. In 16 patients (42%) the response improved and eight patients (21%) were rapidly progressive within 6 months after allo-SCT. In total, 15 patients (39%) were in CR after allo-SCT. The median PFS was 1.4 years (range, 0.1-4.9), and having a CR after allo-SCT or having chronic GVHD resulted in longer PFS. Median OS was 3.1 years (range, 0.2-7.2) and again having a CR after allo-SCT or chronic GVHD was associated with a better OS. Six patients (16%) have died from treatment-related diseases. These results indicate that NMA allo-SCT is a treatment option in relapsed MM patients and that results may be improved by strategies that enhance the CR rate after allo-SCT.

High level of perforin expression in T cells: An early prognostic marker of the severity of herpesvirus reactivation after allogeneic stem cell transplantation in adults.

BACKGROUND: Epstein-Barr virus (EBV) and cytomegalovirus reactivations are frequent complications of hematopoeitic allogeneic stem cell transplantation (SCT) because of a lack of T cell control after immunosuppression. Early diagnosis of reactivation and subsequent preemptive therapy relies on frequent viral load measurement. Additional virus-specific T cell reconstitution data could improve the predictive value of viral load detection for viral complications after transplantation. Here, we studied perforin expression in CD8(+) T cells as a measure of cytotoxic T cell capacity in relation to the occurrence of viral reactivation. METHODS: In a prospective study, we monitored 40 patients during the first 3 months after transplantation and measured viral loads in combination with intracellular perforin expression in CD8(+) T cells. RESULTS: Median perforin expression in CD8(+) T cells throughout follow-up was higher in patients with viral reactivations than in patients without viral reactivations (4.9% vs 2.3%; P = .001). The median percentage of perforin-expressing CD8(+) T cells in patients with high viral reactivations exceeding 1000 copies/mL (10.7%) was statistically significantly higher than that in patients with minor reactivations of 50-1000 copies (4.0%), that in patients with detectable EBV loads that did not exceed the detection limit of 50 copies/mL (2.9%), and that in patients without reactivations (0.8%). Patients with high viral reactivations reached a high percentage of perforin-expressing CD8(+) T cells (>10.2%) more often and faster than did patients with low viral loads (1000 copies/mL) or without viral reactivations. High perforin expression preceded high viral loads. CONCLUSION: Perforin-expressing CD8(+) T cells may be useful as an easy-to-measure prognostic marker for identifying patients at risk for severe viral reactivation very soon after SCT.

Single-centre experience with nonmyeloablative allogeneic stem cell transplantation in patients with multiple myeloma: prolonged remissions induced.

BACKGROUND: The role of allogeneic stem cell transplantation in multiple myeloma is not yet established. METHODS: We retrospectively evaluated the outcome of nonmyeloablative allogeneic stem cell transplantation (NMA) in patients with multiple myeloma treated at the Department of Haematology of the University Medical Centre Utrecht. Thirty-six patients received NMA as part of the first-line treatment; 23 patients as part of salvage therapy. Conditioning regimen was low-dose total body irradiation (TBI, 2 Grays) only; fludarabine was added in patients without previous autologous stem cell transplantation and patients with matched unrelated donors received antithymocyte globulin in addition to fludarabine and TBI. RESULTS: Following NMA overall response increased from 84 to 90%, complete remission rate from 15 to 32%. As part of first-line treatment NMA induced complete remission in 50% of patients vs one patient (4%) treated for relapsed multiple myeloma. Median progression-free survival was 26 months (13 months for the salvage group, 38 months for the 'upfront' patients). Median overall survival has not been reached yet. The achievement of complete remission following NMA as part of first-line treatment was associated with prolonged progression-free and overall survival. Major toxicities were acute and chronic graft-vs-host disease occurring in 64% (23% grade 3-4) and in 54% (49% extensive) patients, respectively. Seven patients (12%) died from nonrelapse mortality, five patients (9%) directly related to toxicity of NMA. CONCLUSION: NMA in multiple myeloma is feasible, is associated with acceptable nonrelapse mortality and may induce prolonged complete remission. In pretreated patients the result of NMA is disappointing which urges new strategies.