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Summary: The clinical and environmental infections caused by AmpC β‐lactamases have been increasingly reported recently. In this study, we characterize the novel chromosome‐encoded AmpC β‐lactamase SFDC‐1 identified in Serratia fonticola strain R28, which was isolated from a rabbit raised on a farm in southern China. SFDC‐1 shared the highest amino acid identity of 79.6% with the functionally characterized AmpC β‐lactamase gene blaYRC‐1, although it had highly homologous functionally uncharacterized relatives in the same species from different sources, including some of the clinical significance. The cloned blaSFDC‐1 exhibited resistance to a broad spectrum of β‐lactam antibiotics, including most cephalosporins with the highest resistance to ampicillin, cefazolin and ceftazidime, with increased MIC levels ≥128‐fold compared with the control strains. The purified SFDC‐1 showed catalytic activities against β‐lactams with the highest catalytic activity to cefazolin. The genetic context of blaSFDC‐1 and its relatives was conserved in the chromosome, and no mobile genetic elements were found surrounding them. [ABSTRACT FROM AUTHOR]

Background: Acute promyelocytic leukemia (APL) is a special type of acute myeloid leukemia Thrombosis is at increased risk complication in patients with this disease. However, the risk factors of thrombosis related to Chinese APL patients are not fully understood. Methods: In this study, clinical and laboratory data of 44 consecutively Chinese APL patients were collected and analyzed. Results: One arterial and 6 venous thrombosis occurred in 44 patients, including 22 males and 22 females, with a median age of 44 years (range from 18 to 74 years). The ratio of male and female gender, age, white blood cell count, hemoglobin, platelets, disease risk stratification, CD2, Khorana score, differentiation syndrome (DS) and gene mutation related to prognosis of APL, including DNMT3A, TET2, IDH1, IDH2, NRAS and ASXL1 in the two groups with and without thrombosis were not statistically significant. The detection rate of PAI-1 genotype 4G4G was 71.4% (5/7) in 7 patients with thrombosis, while the detection rate of PAI-1 genotype 4G4G in 37 patients without thrombosis was 8.1% (3/37). The differences between the two groups in WT-1 (P = 0.01), PAI-1 4G4G (P = 0.0009), bcr3 (P = 0.027), CD15 (P = 0.005), and FLT3-ITD mutation (P = 0.0008) were statistically significant. Using multivariate analysis, the risk factors of venous thrombosis in APL were CD15 (P = 0.043), PAI-1 4G4G (P = 0.009), WT-1 (P = 0.043) and FLT3/ITD (P = 0.013), respectively. Conclusion: Our results suggested the PAI-1 gene 4G4G type, CD15, WT-1 and FLT3-ITD mutations excluding DNMT3A, TET2, IDH1/2, NRAS and ASXL1 are risk factors of thrombotic events in Chinese APL patients. [ABSTRACT FROM AUTHOR]

Aminoglycosides are important options for treating life-threatening infections. However, high levels of aminoglycoside resistance (HLAR) among Klebsiella pneumoniae isolates have been observed to be increasing frequently. In this study, a total of 292 isolates of the K. pneumoniae complex from a teaching hospital in China were analyzed. Among these isolates, the percentage of HLAR strains was 13.7% (40/292), and 15 aminoglycoside resistance genes were identified among the HLAR strains, with rmtB being the most dominant resistance gene (70%, 28/40). We also described an armA -carrying Klebsiella variicola strain KP2757 that exhibited a high-level resistance to all aminoglycosides tested. Whole-genome sequencing of KP2757 demonstrated that the strain contained one chromosome and three plasmids, with all the aminoglycoside resistance genes (including two copies of armA and six AME genes) being located on a conjugative plasmid, p2757-346, belonging to type IncHI5. Comparative genomic analysis of eight IncHI5 plasmids showed that six of them carried two copies of the intact armA gene in the complete or truncated Tn 1548 transposon. To the best of our knowledge, for the first time, we observed that two copies of armA together with six AME genes coexisted on the same plasmid in a strain of K. variicola with HLAR. Comparative genomic analysis of eight armA -carrying IncHI5 plasmids isolated from humans and sediment was performed, suggesting the potential for dissemination of these plasmids among bacteria from different sources. These results demonstrated the necessity of monitoring the prevalence of IncHI5 plasmids to restrict their worldwide dissemination. [ABSTRACT FROM AUTHOR]

Introduction: Human adenovirus (HAdV) is a common pathogen in children with acute respiratory infections (ARIs). The aim was to describe the epidemiology, molecular, and clinical characteristics of HAdV among children hospitalized with ARIs in Wenzhou in southeastern China. Methodology: From January 2018 to December 2019, nasopharyngeal swab or sputum specimens were prospectively collected from hospitalized children with ARIs. HAdV was detected using direct immunofluorescence. We used a multiplex PCR assay combined with capillary electrophoresis targeting the hexon gene's hypervariable region to identify HAdV types 1, 2, 3, 4, 5, 7, 14, 21, 37, 40, 41, and 55. We analyzed the epidemiological, molecular, and clinical data according to the HAdV type. Results: HAdVs were detected in 1,059 (3.5%) of the total of 30,543 children tested. A total of 947 cases with monotype HAdV identified by the PCR assay were included in the analysis. HAdV-3 (415/947, 43.8%), HAdV-7 (318/947, 33.6%), HAdV-2 (108/947, 11.4%), and HAdV-1 (70/947, 7.4%) were the predominant types. Of the 550 (58.1%) cases detected from December 2018 to August 2019, HAdV-3, and HAdV-7 were the main types. The main diagnoses included 358 cases of pneumonia, 232 cases of tonsillitis, 198 cases of bronchitis, and 159 cases of upper respiratory tract infection (URTI). Among children with pneumonia the main types were HAdV-7 (51.1%), HAdV-3 (36.9%), and HAdV-1 (2.2%). Among children with bronchitis, the main types were HAdV-3 (48.0%), HAdV-7 (28.3%), and HAdV-2 (10.6%). Among children with URTIs, the main types were HAdV-3 (49.7%), HAdV-7 (22.6%), and HAdV-2 (13.2%). Among children with tonsillitis, the main types were HAdV-3 (47.4%), HAdV-2 (22.4%), and HAdV-7 (18.5%). In total, 101 (55.2%) patients required supplemental oxygen, 15 (8.2%) required critical care, and 1 child (0.5%) with HAdV-7 pneumonia died. Conclusion: HAdV-3 -7, -2, and -1 were the predominant types identified in hospitalized children with ARIs in Wenzhou. From December 2018 to August 2019, there were outbreaks of HAdV-3 and -7. There were significant differences in HAdV types among children with pneumonia, tonsillitis, bronchitis, and URTI. HAdV-7 can cause more severe pneumonia in children than HAdV-3. [ABSTRACT FROM AUTHOR]

Background: Procalcitonin (PCT) has been recommended and widely used for the prognosis, diagnosis, and monitoring of sepsis. Currently, a majority of PCT detection products are limited to using serum samples, which requires the tedious pre-treatment process, as well as a large sample volume for analysis. Hence, there is an increasing need to replace serum with plasma or whole blood samples. In this work, we evaluated the effects of different blood sample types on PCT quantitative detection by measuring PCT levels in clinically homogenous whole blood, plasma, and serum samples, in hope of extending the application of PCT detection in more sample types., Methods: Ninety patients from Tong Ren Hospital of Shanghai Jiao Tong University, School of Medicine with different PCT levels volunteered for this study. Clinically homogenous samples, including EDTA- K2 anticoagulant whole blood, centrifuged serum and procoagulant plasma, were collected and analyzed using i-Reader S automatic immunoanalyzer and its supporting reagent kits. Passing and Bablok regression analysis, Bland-Altman plotting, and Kappa test were used for consistency analysis and the determination of consistency intensity, respectively., Results: Correlation analysis showed that PCT concentrations measured from EDTA-K2 anticoagulated plasma samples had a good linear regression relationship with PCT from serum samples, with a slope of 0.8741, r = 0.958, p < 0.05. A similar correlation was observed between whole blood and serum, with a slope of 0.9234, r = 0.965, p < 0.05. A good correlation was found from the quantitative results of different sample types obtained from the same patient. In detail, PCT levels in EDTA-K2 anticoagulant whole blood and plasma are well correlated with that in the serum (r = 0.831, p < 0.05; r = 0.814, p < 0.05). There was no significant difference among different sample types (p > 0.05). Variation in PCT quantification induced by different sample types has no statistical influence on positive/negative decision (p > 0.05). Bland-Altman analysis for assessing PCT concentration agreement showed there was no outlier ratio between whole blood and plasma within the range of the detection system, as well as no outlier between serum and plasma. Kappa coefficient of PCT concentration between serum and homologous EDTA-K2 anticoagulated plasma was 0.8942 (p < 0.001), and for serum and homologous whole blood it was 0.6954 (p < 0.001)., Conclusions: We concluded that quantitative PCT detection can be conducted in different sample types with good correlation and consistency, which means that it is feasible to replace serum samples with whole blood and/or plasma samples for PCT detection in clinical use. These findings reduce the sample volume and turnover time of PCT detection in clinical labs, greatly improving the process of PCT detection and promoting the application of PCT as an important inflammatory biomarker for disease diagnosis.

Background: With the wide use of florfenicol to prevent and treat the bacterial infection of domestic animals, the emergence of the florfenicol resistance bacteria is increasingly serious. It is very important to elucidate the molecular mechanism of the bacteria's resistance to florfenicol., Methods: The minimum inhibitory concentration (MIC) levels were determined by the agar dilution method, and polymerase chain reaction was conducted to analyze the distribution of florfenicol resistance genes in 39 CoNS strains isolated from poultry and livestock animals and seafood. The whole genome sequence of one multidrug resistant strain, Staphylococcus lentus H29, was characterized, and comparative genomics analysis of the resistance gene-related sequences was also performed., Results: As a result, the isolates from the animals showed a higher resistance rate (23/28, 82.1%) and much higher MIC levels to florfenicol than those from seafood. Twenty-seven animal isolates carried 37 florfenicol resistance genes (including 26 fexA, 6 cfr and 5 fexB genes) with one carrying a cfr gene, 16 each harboring a fexA gene, 5 with both a fexA gene and a fexB gene and the other 5 with both a fexA gene and a cfr gene. On the other hand, all 11 isolates from seafood were sensitive to florfenicol, and only 3 carried a fexA gene each. The whole genome sequence of S. lentus H29 was composed of a chromosome and two plasmids (pH29-46, pH29-26) and harbored 11 resistance genes, including 6 genes [cfr, fexA, ant(6)-Ia, aacA-aphD, mecA and mph(C)] encoded on the chromosome, 4 genes [cfr, fexA, aacA-aphD and tcaA] on pH29-46 and 1 gene (fosD) on pH29-26. We found that the S. lentus H29 genome carried two identical copies of the gene arrays of radC-tnpABC-hp-fexA (5671 bp) and IS256-cfr (2690 bp), of which one copy of the two gene arrays was encoded on plasmid pH29-46, while the other was encoded on the chromosome., Conclusions: The current study revealed the wide distribution of florfenicol resistance genes (cfr, fexA and fexB) in animal bacteria, and to the best of our knowledge, this is the first report that one S. lentus strain carried two identical copies of florfenicol resistance-related gene arrays.

The diagnosis of tuberculous pericarditis (TBP) remains challenging. This prospective study evaluated the diagnostic value of Xpert MTB/RIF (Xpert) and T-SPOT.TB and adenosine deaminase (ADA) for TBP in a high burden setting. A total of 123 HIV-negative patients with suspected TBP were enrolled at a tertiary referral hospital in China. Pericardial fluids were collected and subjected to the three rapid tests, and the results were compared with the final confirmed diagnosis. Of 105 patients in the final analysis, 39 (37.1%) were microbiologically, histopathologically or clinically diagnosed with TBP. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio (DOR) for Xpert were 66.7%, 98.5%, 96.3%, 83.3%, 44.0, 0.338, and 130.0, respectively, compared to 92.3%, 87.9%, 81.8%, 95.1%, 7.6, 0.088, and 87.0, respectively, for T-SPOT.TB, and 82.1%, 92.4%, 86.5%, 89.7%, 10.8, 0.194, and 55.8, respectively, for ADA (≥ 40 U/L). ROC curve analysis revealed a cut-off point of 48.5 spot-forming cells per million pericardial effusion mononuclear cells for T-SPOT.TB, which had a DOR value of 183.8, while a cut-off point of 41.5 U/L for ADA had a DOR value of 70.9. Xpert (Step 1: rule-in) followed by T-SPOT.TB [cut-off point] (Step 2: rule-out) showed the highest DOR value of 252.0, with only 5.7% (6/105) of patients misdiagnosed. The two-step algorithm consisting of Xpert and T-SPOT.TB could offer rapid and accurate diagnosis of TBP.

Members of the Enterobacter cloacae complex are important opportunistic human pathogens capable of causing a wide variety of infections. During recent decades, aminoglycoside-resistant E. cloacae complex isolates have increasingly been reported and have become a major concern. Here, we employed high-throughput sequencing in combination with specific PCR assays to investigate the prevalence of aminoglycoside resistance genes among 170 isolates of the E. cloacae complex collected from a teaching hospital in Wenzhou, China. A total of 12 known genes [ aphA-1 , strA , strB , aac(6')-IIc , aadA2 , aac(3)-IId , aadB , aadA1 , rmtB , armA , aadA5 , and aac(6')-Ie-aph(2'')-Ia ] and 1 novel gene [ aac(3)-IIg ] were identified, with aphA-1 (71.18%), strA (55.29%), and strB (52.35%) being the most prevalent, and aac(3)-IIg was detected with a positive rate of 21.76% (37/170). The aac(3)-IIg gene was 810 bp in length and encoded a protein that shared 72 to 78% identities with previously known AAC(3)-II aminoglycoside 3- N -acetyltransferases. The MICs of gentamicin and tobramycin were 512 μg/ml and 64 μg/ml, respectively, when aac(3)-IIg was cloned into Escherichia coli DH5α. All aac(3)-IIg -positive isolates exerted broad aminoglycoside resistance profiles, mediated by the coexistence of multiple resistance genes. Moreover, aminoglycoside resistance and resistance genes were found to be transferable in most strains (24/37). Nevertheless, pulsed-field gel electrophoresis (PFGE) and dendrogram analysis showed clonal diversity among these isolates. S1 nuclease PFGE, Southern hybridization, and whole-genome sequencing indicated that aac(3)-IIg was located on transferable as well as nontransferable plasmids of various sizes. The analysis of the genetic environment suggested that aac(3)-IIg is embedded within a class 1 integron, with IS 26 playing an important role in its mobility., (Copyright © 2020 American Society for Microbiology.)