Characterization of bla-positive carbapenem-resistant strains isolated in Guangzhou, China.

Background: Carbapenemase-producing makes a great contribution to carbapenem resistance in Gram-negative bacilli. Bla gene was first discovered by us in Alcaligenes faecalis AN70 strain isolated in Guangzhou of China and, was submitted to NCBI on 16 November 2018.

Methods: Antimicrobial susceptibility testing was performed by broth microdilution assay using BD Phoenix 100.

Selective Photothermal Therapy Based on Lipopolysaccharide Aptamer Functionalized MoS Nanosheet-Coated Gold Nanorods for Multidrug-Resistant Pseudomonas aeruginosa Infection.

Chronic wounds infected by multidrug-resistant gram-negative bacteria have evolved resistance to traditional antibiotic therapy, posing a threat to global public health in recent years. Herein, a selective therapeutic nanorod (MoS -AuNRs-apt) based on molybdenum disulfide (MoS ) nanosheets coated gold nanorods (AuNRs) targeting lipopolysaccharide (LPS) is presented. AuNRs have excellent photothermal conversion efficiency in 808 nm laser-guided photothermal therapy (PTT), and the MoS nanosheets coating significantly enhances the biocompatibility of AuNRs.

Rapid detection of a novel B1-β-lactamase gene, blaAFM-1 using a loop-mediated isothermal amplification (LAMP) assay.

Background: BlaAFM-1 (GenBank Accession No. 143105.1) is a new B1 subclass metallo-β-lactamase gene discovered by our group, and isolated from an Alcaligenes faecalis plasmid that renders carbapenem antibiotics ineffective.

Rapid detection for infected ascites in cirrhosis using metagenome next-generation sequencing: A case series.

Empirical antibiotic therapy in patients with spontaneous bacterial peritonitis (SBP) is common as pathogen(s) are identified in only 5%-20% patients using conventional culture-based techniques. Metagenome next-generation sequencing (mNGS) test is a promising approach for the diagnosis of infectious disease. The clinical application of mNGS for infected ascites in cirrhotic patients is rarely reported.

Heat inactivation of serum interferes with the immunoanalysis of antibodies to SARS-CoV-2.

Background: The detection of serum antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is emerging as a new tool for the coronavirus disease 2019 (COVID-19) diagnosis. Since many coronaviruses are sensitive to heat, heating inactivation of samples at 56°C prior to testing is considered a possible method to reduce the risk of transmission, but the effect of heating on the measurement of SARS-CoV-2 antibodies is still unclear.

Methods: By comparing the levels of SARS-CoV-2 antibodies before and after heat inactivation of serum at 56°C for 30 minutes using a quantitative fluorescence immunochromatographic assay RESULTS: We showed that heat inactivation significantly interferes with the levels of antibodies to SARS-CoV-2.

Molecular characteristics of carbapenem-resistant Acinetobacter spp. from clinical infection samples and fecal survey samples in Southern China.

Background: Carbapenem resistance among Acinetobacter species has become a life-threatening problem. As a last resort in the treatment of gram-negative bacteria infection, resistance to colistin is also a serious problem. The aim of study was to analyze the mechanism of resistance and perform genotyping of carbapenem-resistant Acinetobacter from clinical infection and fecal survey samples in Southern China.

Multiplex real-time PCR assays to detect Stenotrophomonas maltophilia carrying sul1, sul2, and sul3 genes.

Nosocomial infections caused by Stenotrophomonas maltophilia resistant to SXT are increasingly reported worldwide. In this study, a novel melting-curve based multiplex real-time PCR assay for the simultaneous detection of the ssrA and sul1, sul2 and sul3 genes was first established. The assays were performed on a Roche LightCycler® 480 II system.

Detection of common mobile genetic elements and genotyping of multidrug-resistant Gram-negative bacilli in blood specimens from septicemia patients in southern China.

Background: Integron, ISCR1 and complex class 1 integrons lead bacteria to become resistant to antibiotic regimens. The aim of this study was to detect common mobile genetic elements of multidrug-resistant Gram-negative bacilli and evaluate the genotyping of these bacilli in blood specimens from septicemia patients in southern China.

Methods: A total of 837 Gram-negative bacilli including 578 strains containing and 259 strains containing non-fermentative bacilli were investigated in blood samples collected from septicemia patients between 2011 and 2014 in southern China.

Integrons and insertion sequence common region 1 (ISCR1) of carbapenem-non-susceptible Gram-negative bacilli in fecal specimens from 5000 patients in southern China.

The integrons and insertion sequence common region 1 (ISCR1) of 329 carbapenem-non-susceptible Gram-negative bacilli, excluding 60 Stenotrophomonas maltophilia strains, in fecal specimens from 5000 patients in southern China were studied. A total of 205 (62.3%) class 1 integron-positive strains and 126 (61.

Two Multiplex Real-Time PCR Assays to Detect and Differentiate Acinetobacter baumannii and Non- baumannii Acinetobacter spp. Carrying blaNDM, blaOXA-23-Like, blaOXA-40-Like, blaOXA-51-Like, and blaOXA-58-Like Genes.

Nosocomial infections caused by Acinetobacter spp. resistant to carbapenems are increasingly reported worldwide. Carbapenem-resistant Acinetobacter (CRA) is becoming a serious concern with increasing patient morbidity, mortality, and lengths of hospital stay.

New structures simultaneously harboring class 1 integron and ISCR1-linked resistance genes in multidrug-resistant Gram-negative bacteria.

Background: The connection structure of class 1 integron and insertion sequence common region 1 (ISCR1) is called "complex class 1 integrons" or "complex sul1-type integrons", which is also known to be associated with many resistance genes. This structure is a powerful gene-capturing tool kit that can mobilize antibiotic resistance genes. In order to look for and study the structure among clinical multidrug-resistant (MDR) Gram-negative isolates, 63 isolates simultaneously harbored class 1 integron and ISCR1-linked resistance genes were isolated from 2309 clinical non-redundant MDR Gram-negative isolates in Nanfang Hospital in 2008-2013.

Molecular characteristics of carbapenem-resistant gram-negative bacteria in southern China.

A total of 368 nonreplicate gram-negative bacteria with resistance to imipenem or meropenem were collected to search for carbapenemase genes, class 1 integrons, and insertion sequence with common region 1 (ISCR1). The carbapenemase genes blaIMP-4, blaKPC-2, and blaNDM-1 were found in two Enterobacteriaceae and seven Pseudomonas aeruginosa isolates, nine Klebsiella pneumoniae isolates, and seven Enterobacteriaceae and two Acinetobacter spp. isolates.

[Combined drug sensitivity test of 50 strains of extensively drug-resistant Acinetobacter baumannii].

Objective: To study the in vitro antibacterial activity of meropenem combined with doxycycline, ciprofloxacin, sulbactam or cefoperazone/sulbactam against clinically isolated extensively drug-resistant Acinetobacter baumannii (XDRAB).

Methods: Using a checker board synergy design, the minimal inhibitory concentration (MIC) of antibiotics against 50 isolates of XDRAB was determined by broth microdilution antifungal susceptibility test. The fractional inhibitory concentration (FIC) index was calculated to determine the combined effect of the antibiotics.

Rapid detection of blaNDM, blaKPC, blaIMP, and blaVIM carbapenemase genes in bacteria by loop-mediated isothermal amplification.

A loop-mediated isothermal amplification (LAMP) assay was developed and evaluated for rapid detection of blaKPC, blaNDM, blaIMP, and blaVIM carbapenemase genes. Six oligonucleotides, including outer, inner, and loop primers, were designed for eight distinct regions in each target gene. Two qualitative criteria were used to evaluate LAMP reactions: visual inspection of color change and real-time detection of fluorescence change.

Construction and characterization of a Vibrio cholerae serogroup O139 vaccine candidate by genetic engineering.

The present study aimed to construct and evaluate the live attenuated Vibrio cholerae serogroup O139 vaccine candidate, in which genes encoding protective antigens were integrated into the chromosomal DNA. Using the initial strain, O139-ZJ9693, the toxin-linked cryptic (TLC) and cholera toxin (CTX) genetic elements and repeats in the toxin (RTX) gene cluster were deleted from its chromosomal DNA, and the cholera toxin genes, ctxB and rstR, were transferred into the chromosome to construct the candidate vaccine strain. The expression of ctxB and the vaccine virulence were then examined.

Molecular identification of clinical "difficult-to-identify" microbes from sequencing 16S ribosomal DNA and internal transcribed spacer 2.

Background: Clinical microbiology laboratories have to accurately identify clinical microbes. However, some isolates are difficult to identify by the automated biochemical text platforms, which are called "difficult-to-identify" microbes in this study. Therefore, the ability of 16S ribosomal DNA (16S rDNA) and internal transcribed spacer 2 (ITS2) sequencing to identify these "difficult-to-identify" bacteria and fungi was assessed in this study.

The establishment of a duplex real-time PCR assay for rapid and simultaneous detection of blaNDM and blaKPC genes in bacteria.

The latest threat of multidrug-resistant Gram-negative bacteria corresponds to the emergence of carbapenemase New Delhi metallo-β-lactamase (NDM) and Klebsiella pneumoniae carbapenemase (KPC) producers. Rapid molecular detection is essential to limit their spread. In this study, a duplex real-time polymerase chain reaction (PCR) that was specific for the detection of blaNDM and blaKPC with the same limit of detection of ten plasmid copies was developed.

Class 1 integrons in urinary isolates of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in Southern China during the past five years.

We analyzed extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (226) and Klebsiella pneumoniae (53) collected from urine specimens during 2005-2009 for the presence of ESBL genes, class 1 integrons, and characterization of gene cassettes. TEM and CTX-M β-lactamase genes were the most prevalent. One hundred and forty-four E.

Novel ISCR1-linked resistance genes found in multidrug-resistant Gram-negative bacteria in southern China.

Non-duplicate multidrug-resistant (MDR) Gram-negative bacteria (n=1329) isolated from southern China between January 2008 and December 2009 were investigated for the presence of ISCR1 as well as characterisation of ISCR1-linked resistance genes. Of 433 ISCR1-positive strains, 151 appeared to carry ISCR1-linked resistance genes. Seven different ISCR1-linked resistance gene arrays were identified by restriction fragment length polymorphism (RFLP) and DNA sequencing analysis.

Class 1 integron gene cassettes in multidrug-resistant Gram-negative bacteria in southern China.

Non-duplicate multidrug-resistant Gram-negative bacteria (n=1447) isolated from January 2008 to December 2009 were investigated for the presence of integrons as well as characterisation of gene cassettes. Among 825 strains carrying the class 1 integrase gene intI1, 461 gene cassette-positive isolates were found. Thirty-eight distinct gene cassette arrays were identified by restriction fragment length polymorphism (RFLP) and DNA sequencing analyses.

[Analysis of distribution, drug resistance and risk factors of pathogens isolated from septicemic patients].

Objective: To investigate distribution, drug resistance and risk factors of pathogens isolated from septicemic patients in a hospital in the past 6 years.

Methods: Most of the bacterial isolates were identified with BD Phoenix, and a few isolates were identified manually and with K-B method. Candida isolates were identified with color display plates and K-B method.

[ALL 98 strains of Brucella OMP25 gene is conservative in China].

Objective: To investigate the genetic polymorphism of OMP25 gene isolated from 116 Brucella strains, including 18 Brucella reference strains and 98 Chinese field strains.

Methods: Chromosomal DNA of Brucella strains were analyzed by PCR, and then the product OMP25 gene was digested with Hind III and separated on 10% polypropylene agarose gel electrophoresis. OMP25 genes of different types were sequenced.

[Distribution and drug resistance spectrum analysis of 2478 clinical bacterial and Candida isolates].

Objective: To investigate the distribution and drug resistance spectrum of clinical bacterial and Candida isolates.

Methods: Most of the bacterial isolates were identified using automated BD Phoenix, and a few with K-B method carried out manually. Candida isolates were identified by color-display plate and K-B method.

[Sequence analysis of housekeeping genes recA, dnaE, and mdh in different serogroups or biotypes of Vibrio cholerae isolated from China].

Objective: To analyze sequences of the housekeeping genes including recA, dnaE, and mdh in different serogroups or different biotypes of Vibrio cholerae (VC) strains isolated from China.

Methods And Results: recA, dnaE, and mdh genes of Vibrio cholerae were obtained by PCR, sequenced and analyzed. Forty-four variable bases were identified in the 500 bases of recA gene of 18 VC strains, and the mutation of only 3 variable bases could result in changes of 2 amino acids.