Study on multidrug resistance related genes of Salmonella isolated from food and clinical samples

ObjectiveTo investigate distribution of integron and extended-spectrum β-lactamase produced by Salmonella isolated from food and clinical samples， and explore the relationship between different drug resistance genes and multidrug resistance.MethodsPhenotype of ESBL-producing strains were confirmed by K-B method. The ESBL related drug resistance genes （blaTEM， blaSHV， blaCTX） and the mobile element integron in Salmonella were amplified by polymerase chain reaction. The amplified products of integron variable region were sequenced and the drug resistance gene cassettes were analyzed.ResultsThree hundred and nine Salmonella strains were isolated. A total of 138 Salmonella strains were isolated from food， including poultry （n=96）， raw pork （n=19） and aquatic products （n=23）. One hundred and seventy one Salmonella strains were isolated from clinical samples. The drug resistance rate of 309 Salmonella strains was 78.3%， and the multidrug resistance rate was 41.1%. The antimicrobial resistance rate of poultry was the highest. A total of 56 ESBL-producing strains were detected， of which 35 strains carried the ESBL genes （15 strains carried blaTEM； 10 strains carried blaCTX， 10 strains carried blaTEM and blaCTX ）. The blaSHV gene was not detected. A total of 98 strains which carried class I integron gene were detected， and the positive rate was 31.7%. Among the 98 strains， 54 strains carried drug resistance gene cassette. Forty seven strains carried dfrA and aadA， 1 strain carried linG-aadA22， the rest were empty gene cassette. The multi-drug resistance rates of integron positive and ESBL-producing strains were as high as 98.0% and 89.3%， respectively. The positive rate of integron in ESBL-producing strains was 76.8% （43/56）.ConclusionThe class I integron and ESBL-producing Salmonella were widely distributed in this area. The genotypes of ESBL-producing strains were mainly blaTEM and blaCTX. Both integron and ESBL-producing strains were associated with multidrug resistance. The dug resistance situation of Salmonella in this area was serious， and it was particularly necessary to pay attention to the standardized use of antibiotics in poultry breeding

Convergence of resistance and evolutionary responses in Escherichia coli and Salmonella enterica co-inhabiting chicken farms in China

Sharing of genetic elements among different pathogens and commensals inhabiting same hosts and environments has significant implications for antimicrobial resistance (AMR), especially in settings with high antimicrobial exposure. We analysed 661 Escherichia coli and Salmonella enterica isolates collected within and across hosts and environments, in 10 Chinese chicken farms over 2.5 years using novel data-mining methods. Most isolates within same hosts possessed same clinically relevant AMR-carrying mobile genetic elements (plasmids: 70.6%, transposons: 78%), which also showed recent common evolution. Machine learning revealed known and novel AMR-associated mutations and genes underlying resistance to 28 antimicrobials and primarily associated with resistance in E. coli and susceptibility in S. enterica. Many were essential and affected same metabolic processes in both species, albeit with varying degrees of phylogenetic penetration. Multi-modal strategies are crucial to investigate the interplay of mobilome, resistance and metabolism in cohabiting bacteria, especially in ecological settings where community-driven resistance selection occurs

Cytokine and chemokine levels in patients with severe fever with thrombocytopenia syndrome virus.

BACKGROUND: Severe fever with thrombocytopenia syndrome virus (SFTSV), which can cause hemorrhagic fever-like illness, is a newly discovered bunyavirus in China. The pathogenesis of SFTSV infection is poorly understood. However, it has been suggested that immune mechanisms, including cytokines and chemokines, play an important role in disease pathogenesis. In the present study, we investigated host cytokine and chemokine profiles in serum samples of patients with SFTSV infection from Northeast China and explored a possible correlation between cytokine levels and disease severity. METHODS AND PRINCIPAL FINDINGS: Acute phase serum samples from 40 patients, diagnosed with SFTSV infection were included. Patients were divided into two groups--severe or non-severe--based on disease severity. Levels of tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, interleukin-6, interferon (IFN)-γ, IFN- γ-induced protein (IP)-10 and RANTES were measured in the serum samples with commercial ELISAs. Statistical analysis showed that increases in TNF-α, IP-10 and IFN-γ were associated with disease severity. CONCLUSIONS: We suggest that a cytokine-mediated inflammatory response, characterized by cytokine and chemokine production imbalance, might be in part responsible for the disease progression of patients with SFTSV infection

Correlations between variables were assessed using the Pearson test.

<p><i>P</i><0.05 was considered significant. Symbols and colors: red diamonds, severe patients; blue circles, non-severe patients.</p

Differences in clinical and laboratory characteristics between severe and non-severe cases of SFTSV infection.

<p>Data are median (interquartile range).</p>a<p>Severe versus non-severe.</p

Characteristics of 40 SFTSV-infected patients included in the study.

<p>Characteristics of 40 SFTSV-infected patients included in the study.</p

Clinical Features and Factors Associated with Severity and Fatality among Patients with Severe Fever with Thrombocytopenia Syndrome Bunyavirus Infection in Northeast China

<div><p>Background</p><p>In 2009, severe fever with thrombocytopenia syndrome virus (SFTSV) was identified as a novel member of the genus phlebovirus in the Bunyaviridae family in China. The detailed clinical features of cases with SFTSV infection have not been well described, and the risk factors for severity among patients and fatality among severe patients remain to be determined.</p> <p>Methodology/Principal Findings</p><p>Clinical and laboratory features of 115 hospitalized patients with SFTSV infection during the period from June 2010 to December 2011 in Northeast China were retrospectively reviewed. We assessed the risk factors associated with severity in confirmed cases and fatality in severe cases by multivariate analysis. One hundred and three (89.6%) of 115 patients presented with multiple organ dysfunction, and 22 (19.1%) of 115 proceeded to the stage of life threatening multiple organ failure. Of the 115 patients, 14 fatalities (12.2%) were reported. Multivariate analysis demonstrated that the independent predictors of risk for severity were: albumin ≤30 g/l (OR, 8.09; 95% CI, 2.58-25.32), APTT ≥ 66 seconds (OR, 14.28; 95% CI, 3.28-62.24), sodium ≤130 mmol/l (OR, 5.44; 95% CI, 1.38-21.40), and presence of neurological manifestations (OR, 7.70; 95% CI, 1.91-31.12). Among patients with severe disease, presence of acute lung injury/acute respiratory distress syndrome (HR, 4.59; 95% CI, 1.48–14.19) and disseminated intravascular coagulation (HR, 4.24; 95% CI, 1.38–13.03) were independently associated with fatality.</p> <p>Conclusions/Significance</p><p>SFTSV infection may present with more severe symptoms and laboratory abnormalities than hitherto reported. Due to infection with a novel bunyavirus, the patients may sufferer multiple organ dysfunction and die of multiple organ failure. In the clinical assessment of any case of SFTS, independent factors relating to prognosis need to be taken into account by clinicians.</p> </div