Carbapenem-resistant
(CRE) represent a health threat, but effective control interventions remain unclear. Hospital wastewater sites are increasingly being highlighted as important potential ...reservoirs. We investigated a large
carbapenemase (KPC)-producing
outbreak and wider CRE incidence trends in the Central Manchester University Hospital NHS Foundation Trust (CMFT) (United Kingdom) over 8 years, to determine the impact of infection prevention and control measures. Bacteriology and patient administration data (2009 to 2017) were linked, and a subset of CMFT or regional hospital KPC-producing
isolates (
= 268) were sequenced. Control interventions followed international guidelines and included cohorting, rectal screening (
= 184,539 screens), environmental sampling, enhanced cleaning, and ward closure and plumbing replacement. Segmented regression of time trends for CRE detections was used to evaluate the impact of interventions on CRE incidence. Genomic analysis (
= 268 isolates) identified the spread of a KPC-producing
outbreak clone (strain A, sequence type 216 ST216;
= 125) among patients and in the environment, particularly on 2 cardiac wards (wards 3 and 4), despite control measures. ST216 strain A had caused an antecedent outbreak and shared its KPC plasmids with other
lineages and
species. CRE acquisition incidence declined after closure of wards 3 and 4 and plumbing replacement, suggesting an environmental contribution. However, ward 3/ward 4 wastewater sites were rapidly recolonized with CRE and patient CRE acquisitions recurred, albeit at lower rates. Patient relocation and plumbing replacement were associated with control of a clonal KPC-producing
outbreak; however, environmental contamination with CRE and patient CRE acquisitions recurred rapidly following this intervention. The large numbers of cases and the persistence of
in
, including pathogenic lineages, are of concern.
A number of pathogens induce immature dendritic cells (iDC) to migrate to lymphoid organs where, as mature DC (mDC), they serve as efficient APC. We hypothesized that pathogen recognition by iDC is ...mediated by Toll-like receptors (TLRs), and asked which TLRs are expressed during the progression of monocytes to mDC. We first measured mRNA levels for TLRs 1-5 and MD2 (a protein required for TLR4 function) by Northern analysis. For most TLRs, message expression decreased severalfold as monocytes differentiated into iDC, but opposing this trend, TLR3 and MD2 showed marked increases during iDC formation. When iDC were induced to mature with LPS or TNF-alpha, expression of most TLRs transiently increased and then nearly disappeared. Stimulation of iDC, but not mDC, with LPS resulted in the activation of IL-1 receptor-associated kinase, an early component in the TLR signaling pathway, strongly suggesting that LPS signals through a TLR. Surface expression of TLRs 1 and 4, as measured by mAb binding, was very low, corresponding to a few thousand molecules per cell in monocytes, and a few hundred or less in iDC. We conclude that TLRs are expressed in iDC and are involved in responses to at least one pathogen-derived substance, LPS. If TLR4 is solely responsible for LPS signaling in humans, as it is in mice, then its extremely low surface expression implies that it is a very efficient signal transducer in iDC.
Whole-genome sequencing potentially represents a single, rapid and cost-effective approach to defining resistance mechanisms and predicting phenotype, and strain type, for both clinical and ...epidemiological purposes. This retrospective study aimed to determine the efficacy of whole genome-based antimicrobial resistance prediction in clinical isolates of Escherichia coli and Klebsiella pneumoniae.
Seventy-four E. coli and 69 K. pneumoniae bacteraemia isolates from Oxfordshire, UK, were sequenced (Illumina HiSeq 2000). Resistance phenotypes were predicted from genomic sequences using BLASTn-based comparisons of de novo-assembled contigs with a study database of >100 known resistance-associated loci, including plasmid-associated and chromosomal genes. Predictions were made for seven commonly used antimicrobials: amoxicillin, co-amoxiclav, ceftriaxone, ceftazidime, ciprofloxacin, gentamicin and meropenem. Comparisons were made with phenotypic results obtained in duplicate by broth dilution (BD Phoenix). Discrepancies, either between duplicate BD Phoenix results or between genotype and phenotype, were resolved with gradient diffusion analyses.
A wide variety of antimicrobial resistance genes were identified, including blaCTX-M, blaLEN, blaOKP, blaOXA, blaSHV, blaTEM, aac(3')-Ia, aac-(3')-IId, aac-(3')-IIe, aac(6')-Ib-cr, aadA1a, aadA4, aadA5, aadA16, aph(6')-Id, aph(3')-Ia, qnrB and qnrS, as well as resistance-associated mutations in chromosomal gyrA and parC genes. The sensitivity of genome-based resistance prediction across all antibiotics for both species was 0.96 (95% CI: 0.94-0.98) and the specificity was 0.97 (95% CI: 0.95-0.98). Very major and major error rates were 1.2% and 2.1%, respectively.
Our method was as sensitive and specific as routinely deployed phenotypic methods. Validation against larger datasets and formal assessments of cost and turnaround time in a routine laboratory setting are warranted.
Members of the Toll-like receptor (TLR) family are components of the mammalian anti-microbial response, signaling with a domain closely related to that of IL-1 receptors. In this report the ...expression and function of TLR1, a TLR of unknown function, are examined. TLR1 is expressed by monocytes, as demonstrated using a novel mAb. Monocytes also express TLR2. TLR1 transfection of HeLa cells, which express neither TLR1 nor TLR2, was not sufficient to confer responsiveness to several microbial extracts. However, cotransfection of TLR1 and TLR2 resulted in enhanced signaling by HeLa cells to soluble factors released from Neisseria meningitidis relative to the response with either TLR alone. This phenomenon was also seen with high concentrations of some preparations of LPS. The N. meningitidis factors recognized by TLR1/TLR2 were not released by N. meningitidis mutant in the LpxA gene. Although LpxA is required for LPS biosynthesis, because cooperation between TLR1 and TLR2 was not seen with all LPS preparations, the microbial component(s) TLR1/2 recognizes is likely to be a complex of LPS and other molecules or a compound metabolically and chemically related to LPS. The functional IL-1R consists of a heterodimer; this report suggests a similar mechanism for TLR1 and TLR2, for certain agonists. These data further suggest that mammalian responsiveness to some bacterial products may be mediated by combinations of TLRs, suggesting a mechanism for diversifying the repertoire of Toll-mediated responses.
To investigate trends in Escherichia coli resistance, bacteraemia rates and post-bacteraemia outcomes over time.
Trends in E. coli bacteraemia incidence were monitored from January 1999 to June 2011 ...using an infection surveillance database including microbiological, clinical risk factor, infection severity and outcome data in Oxfordshire, UK, with imported temperature/rainfall data.
A total of 2240 E. coli (from 2080 patients) were studied, of which 1728 (77%) were susceptible to co-amoxiclav, cefotaxime, ciprofloxacin and gentamicin. E. coli bacteraemia incidence increased from 3.4/10,000 bedstays in 1999 to 5.7/10,000 bedstays in 2011. The increase was fastest around 2006, and was essentially confined to organisms resistant to ciprofloxacin, co-amoxiclav, cefotaxime and/or aminoglycosides. Resistant E. coli isolation rates increased similarly in those with and without recent hospital contact. The sharp increase also occurred in urinary isolates, with similar timing. In addition to these long-term trends, increases in ambient temperature, but not rainfall, were associated with increased E. coli bacteraemia rates. It is unclear whether resistant E. coli bacteraemia rates are currently still increasing incidence rate ratio = 1.07 per annum (95% CI = 0.99-1.16), P = 0.07, whereas current susceptible E. coli bacteraemia rates are not changing significantly incidence rate ratio = 1.01 (95% CI = 0.99-1.02). However, neither mortality nor biomarkers associated with mortality (blood creatinine, urea/albumin concentrations, neutrophil counts) changed during the study.
E. coli bacteraemia rates have risen due to rising rates of resistant organisms; little change occurred in susceptible E. coli. Although the severity of resistant infections, and their outcome, appear similar to susceptible E. coli in the setting studied, the increasing burden of highly resistant organisms is alarming and merits on-going surveillance.
Aims: To determine the relevance of lymphopenia to the diagnosis of bacteraemia in patients admitted with medical emergencies, relative to peripheral blood white cell count and neutrophilia. ...Patients/Methods: A two year cohort study carried out in a teaching hospital in Oxford, UK of 21 495 consecutive adult emergency admissions to general medical or infectious disease wards. Full blood data were available in 21 372 cases; 41 cases with extreme full blood count results (neutrophil count, > 75 × 109/litre; lymphocyte count, > 10 × 109/litre) were excluded, leaving 21 331 cases for analysis. The association between the admission lymphocyte and neutrophil counts and the risk of bacteraemia was assessed. Results: Neutrophilia and lymphopenia were both associated with bacteraemia. Lymphopenia was the better predictor in this cohort. Both neutrophilia and lymphopenia were more predictive of bacteraemia than the total white blood cell count. Conclusions: Both lymphocyte and neutrophil counts, rather than total white blood cell count, should be considered in adult medical admissions with suspected bacteraemia.
Saliva for Detection of SARS-CoV-2 Markewitz, Robert D.H; Wandinger, Klaus-Peter; Junker, Ralf ...
The New England journal of medicine,
03/2021, Letnik:
384, Številka:
9
Journal Article
Recenzirano
Odprti dostop
To the Editor:
Wyllie and colleagues (Sept. 24 issue)
1
provide helpful data regarding the use of saliva samples for the detection of SARS-CoV-2 by reverse-transcriptase polymerase chain reaction ...(RT-PCR). We would like to call attention to one detail. For most of the PCR data, absolute quantification was applied, which provided data on the viral load of the samples in units of copies per milliliter. Wyllie et al. did so using a formula that was based on a standard curve that was generated by measuring serial dilutions of known quantities of SARS-CoV-2 RNA transcripts, which was done during a previous study.
2
. . .
We questioned the significance of haplotype structure in gene regulation by testing whether individual single nucleotide polymorphisms (SNPs) within a gene promoter region interleukin-1-beta (IL1B) ...might affect promoter function and, if so, whether function was dependent on haplotype context. We sequenced genomic DNA from 25 individuals of diverse ethnicity, focusing on exons and upstream flanking regions of genes of the cluster. We identified four IL1B promoter region SNPs that were active in transient transfection reporter gene assays. To substantiate allelic differences found in reporter gene assays, we also examined nuclear protein binding to promoter sequence oligonucleotides containing different alleles of the SNPs. The effect of individual SNPs on reporter gene transcription varied according to which alleles of the three other SNPs were present in the promoter construct. The SNP patterns that influenced function reflected common haplotypes that occur in the population, suggesting functionally significant interactions between SNPs according to haplotype context. Of the haplotypes that include the four functional IL1B promoter SNPs (−3737, −1464, −511, −31), the four haplotypes that showed different contextual effects on SNP function accounted for >98% of the estimated haplotypes in Caucasian and African-American populations. This finding underlines the importance of understanding the haplotype structure of populations used for genetic studies and may be especially important in the functional analysis of genetic variation across gene regulatory regions.
Summary Despite the importance of healthcare-associated infection, few studies have quantified the association between severe infection and hospital exposure in UK populations. Our aim was to ...estimate the proportion of the population with recent hospital admission, together with rates of infection in hospital-exposed and hospital-naïve populations. We studied bacteraemia as a marker of severe infection in a population of 550 000, served by two hospitals, between 1 April 2000 and 31 March 2005. Hospital-exposed persons accounted for 8.3% of the population, defined as having been resident in a hospital in the last year. The hospital-exposed population accounted for 55% of all admissions, and 42% of emergency admissions to medical, paediatric or surgery departments. After adjustment for age, the hospital-exposed group had much higher rates of admission bacteraemia. Age-standardised incidence rate ratios relative to hospital-naïve patients were 43 95% confidence interval (CI): 22–85 for meticillin-resistant Staphylococcus aureus (MRSA), 20 (15–27) for S. aureus other than MRSA, 7.3 (5.2–10) for Streptococcus pneumoniae , and 14 (11–18) for E. coli . MRSA was common among hospital-exposed admissions, including emergencies in hospital-exposed men, rates of admission MRSA bacteraemia (31 per 100 000 per annum) and S. pneumoniae bacteraemia (33 per 100 000 per annum) were similar. This quantitative analysis confirms that prior hospital admission is a major risk factor for bacteraemia on hospital admission; it is unclear whether acquisition of pathogens in hospital, co-morbidity or other factors explain this.
Meningococcal disease severity correlates with circulating concentrations of lipopolysaccharide (LPS) and proinflammatory cytokines. Disruption of the lpxA gene of Neisseria meningitidis generated a ...viable strain that was deficient of detectable LPS. The potency of wild-type N. meningitidis to elicit tumor necrosis factor (TNF)—α production by human monocyte-derived macrophages was ∼ 10-fold greater than that of the lpxA mutant. Killed wild-type N. meningitidis and its soluble products induced interleukin (IL)—8 and TNF-α secretion by transfected HeLa cells expressing Toll-like receptor (TLR) 4/MD2, but the lpxA mutant was inactive via this pathway. In contrast, both strains induced IL-8 promoter activity in TLR2-transfected HeLa cells. These data provide evidence that N. meningitidis contains components other than LPS that can elicit biological responses via pathways that are independent of the TLR4/MD2 receptor system, and TLR2 is one of these alternate pathways. These findings have implications for future therapeutic strategies against meningococcal disease on the basis of the blockade of TLRs and the modulation of LPS activity.
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