Recent Transmission and Prevalent Characterization of the Beijing Family Mycobacterium tuberculosis in Jiangxi, China.

The Beijing genotype is the most common type of tuberculosis in Jiangxi Province, China. The association of population characteristics and their prevalence in the development of recent transmission is still unclear. 1,433 isolates were subjected to drug-resistant tests and MIRU-VNTR analysis. We compared differences in demographic characteristics and drug resistance patterns between the Beijing and non-Beijing family strains. We also explored the association of the clustering rate with the Beijing genotype of Mycobacterium tuberculosis. The Beijing genotype was dominant (78.16%). The results of MIRU-VNTR showed that 775 of 1,433 strains have unique patterns, and the remaining gather into 103 clusters. A recent transmission rate was 31.54% (452/1,433). The Beijing genotype strains were more likely to spread among the recurrent population (p = 0.004), people less than 50 years of age (p = 0.02 or 0.003), and the personnel in the northern regions (p = 0.03). Drug resistance patterns did not show significant differences between Beijing and non-Beijing genotype isolates. Furthermore, we found that HIV-positive cases had a lower clustering rate (p = 0.001). Our results indicated that the recurrent population and people under 50 years of age were more likely to be infected with the Beijing genotype of M. tuberculosis. The strains from the Beijing family were easier to cluster compared to strains isolated from the non-Beijing family. Social activity and AIDS substantially impacted the clustering rate of the Beijing genotype of M. tuberculosis. Multidrug resistant M. tuberculosis affected Beijing genotype transmission.

Accessory Gene Regulator (agr) Allelic Variants in Cognate Staphylococcus aureus Strain Display Similar Phenotypes.

The accessory gene regulator (agr) quorum-sensing system is an important global regulatory system of Staphylococcus aureus and contributes to its pathogenicity. The S. aureus agr system is divided into four agr groups based on the amino acid polymorphisms of AgrB, AgrD, and AgrC. The agr activation is group-specific, resulting in variations in agr activity and pathogenicity among the four agr groups. Strains with divergent agr system always have different phenotypes. In the present report, we, respectively, exchanged the agr system of a certain S. aureus with other three agr alleles and assessed the corresponding phenotypes of these congenic strains. Replacement of the agr system led to significant variations in hemolytic activity, protein expression, and virulence gene expression comparing with that of the parental strain. Interestingly, we found that the biological characteristics of these agr congenic strains in the same strain background were highly similar to each other, and the allele-dependent differences of the agr systems were weakened. These findings indicate that the allele-dependent agr predilections of S. aureus are determined by some factors in addition to the polymorphisms of AgrB, AgrD, and AgrC. Future studies may reveal the novel mechanism to improve our understanding of the agr network.

cydA, spdC, and mroQ are novel genes involved in the plasma coagulation of Staphylococcus aureus.

Coagulation is a critical pathogenic process in Staphylococcus aureus. Although the agglutination of S. aureus has been studied for a long time, the genes involved in this process are not completely clear. We performed tube agglutination and dynamic turbidimetry tests to identify novel genes involved in reduced plasma coagulation. A total of 15 genes were identified, including coa, clfA, vwbp, saeS, agrA, trpC, spdC, mroQ, cydA, qoxC, sucC, pyrP, menH, threonine aldolase, and truncated transposase for IS1272. The functions of these genes include bicomponent regulation, membrane transport, energy metabolism and biosynthesis, respectively. cydA, spdC, and mroQ genes were further studied by gene knockout and complementation. Results of gene knockout and complementation and real-time-qPCR proved that cydA, spdC, and mroQ genes are necessary for plasma coagulation. Furthermore, the survival ability of 7 day mice decreased significantly when cydA, spdC, and mroQ genes had been knocked out.

Treatment with the traditional Chinese medicine BuYang HuanWu Tang induces alterations that normalize the microbiome in ASD patients.

Autism spectrum disorders (ASDs) are prevalent neurobiological conditions with complicated causes worldwide. Increasing researcher awareness of ASD and accumulated evidence suggest that the development of ASD may be strongly linked to the dysbiosis of the gut microbiota. In addition, most of the current studies have compared autistic children and neurotypical children or have compared ASD patients before and after antibiotic treatment. Treatment of autism with traditional Chinese medicine (TCM) has increasingly been promoted, but the relationship between its efficacy and intestinal flora has rarely been reported. Under the premise that treatment with the TCM BuYang HuanWu Tang is effective, we conducted a comparative bioinformatics analysis to identify the overall changes in gut microbiota in relation to ASD by comparing the intestinal flora before and after treatment with TCM and contrasting the intestinal flora with that of healthy controls. At the phylum level, Proteobacteria showed a significant increase in children with ASD, which may be a signature of dysbiosis in the gut microbiota. At the genus level, Blautia, Coprococcus 1, the Lachnospiraceae family, and the Ruminococcaceae family were found at the lowest levels of relative abundance in children with ASD, whereas the abundances of Escherichia-Shigella, Klebsiella, and Flavonifractor were significantly increased compared with those in the healthy control group. In sum, this study characterized the alterations of the intestinal microbiome in children with ASD and its normalization after TCM treatment (TCMT), which may provide novel insights into the diagnosis and therapy of ASD.

Application of combined cerebrospinal fluid physicochemical parameters to detect intracranial infection in neurosurgery patients.

Routine test of cerebrospinal fluid (CSF), such as glucose concentrations, chloride ion, protein and leukocyte, as well as color, turbidity and clot, were important indicators for intracranial infection. However, there were no models to predict the intracranial infection with these parameters. We collected data of 221 cases with CSF positive-culture and 50 cases with CSF negative culture from January 1, 2016 to December 31, 2018 in the First Affiliated Hospital of Nanchang University, China. SPSS17.0 software was used to establish the model by adopting seven described indicators, and P < 0.05 was considered as statistically significant. Meanwhile, 40 cases with positive-culture and 10 cases with negative-culture were selected to verify the sensitivity and specificity of the model. The results showed that each parameter was significant in the model establishment (P < 0.05). To extract the above seven parameters, the interpretation model C was established, and C = 0.952-0.183 × glucose value (mmol/L) - 0.024 × chloride ion value (mmol/L)- 0.000122 × protein value (mg/L) - 0.0000859 × number of leukocytes per microliter (× 106/L) + 1.354 × color number code + 0.236 × turbidity number code + 0.691 × clot number code. In addition, the diagnostic sensitivity and specificity of the model were 85.0 and 100%, respectively. The combining application of seven physicochemical parameters of CSF might be of great value in the diagnosis of intracranial infection for adult patients.

Development of Therapeutic Gramicidin S Analogues Bearing Plastic ß,γ-Diamino Acids.

Gramicidin S (GS), one of the most widely investigated antimicrobial peptides (AMPs), is known for its robust antimicrobial activity. However, it is restricted to topical application due to undesired hemolytic activity. With the aim of obtaining nontoxic GS analogues, we describe herein a molecular approach in which the native GS ß-turn region is replaced by synthetic ß,γ-diamino acids (ß,γ-DiAAs). Four ß,γ-DiAA diastereomers were employed to mimic the ß-turn structure to afford GS analogues GS3-6, which exhibit diminished hemolytic activity. A comparative structural study demonstrates that the (ßR,γS)-DiAA is the most-stable ß-turn mimic. To further improve the therapeutic index (e. g., high antibacterial activity and low hemolytic activity) and to extend the molecular diversity, GS5 and GS6 were used as structural scaffolds to introduce additional hydrophobic or hydrophilic groups. We show that GS6K, GS6F and GS display comparable antibacterial activity, and GS6K and GS6F have significantly decreased toxicity. Moreover, antibacterial mechanism studies suggest that GS6K kills bacteria mainly through the disruption of the membrane.

Recurrence Is a Noticeable Cause of Rifampicin-Resistant Mycobacterium tuberculosis in the Elderly Population in Jiangxi, China.

Setting: Rifampicin-resistant tuberculosis (RR-TB) in elderly people in Jiangxi Province, China. Objective: To investigate the incidence of RR-TB and risk factors in elderly people within a hospital setting in China. Design: Retrospective cohort study. Methods: A comparative study was performed to analyze RR-TB and rifampicin-susceptible TB (RS-TB). The 15-locus mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR) method was used to distinguish between relapse and reinfection. Results: Twenty-three recurrent cases occurred in 151 elderly patients with RR-TB, and 24 recurrent cases occurred in 466 elderly patients with RS-TB during this period. TB recurrence was significantly different in the RR-TB and RS-TB groups (OR = 0.35, 95% CI: 0.14-0.88; χ2 = 5.28, P = 0.03). Comparing the risk factors for RR-TB and RS-TB, we found that educational level, age, and pulmonary cavity were inextricably linked to RR-TB in elderly patients. Furthermore, pulmonary cavity, HIV status, and alcohol consumption were associated with recurrence in elderly RR-TB patients. Conclusions: Recurrence is an important source of RR-TB in the elderly population. It is necessary to promptly treat tuberculosis patients, prevent the spread of AIDS, and reduce alcohol intake to control recurrent RR-TB in the elderly population.

Prevalence and molecular characterization of multidrug-resistant M. tuberculosis in Jiangxi province, China.

Multidrug-resistant Mycobacterium tuberculosis (MDR-TB) is a severe health threat to human beings; however, the epidemic and molecular characteristics exist along with the change in the geographic environment and genealogy. Jiangxi province is located in southeast China, which is a high-MDR-TB burden area. Rifampin (RIF) and isoniazid (INH) are the most important first-line anti-tuberculosis drugs. The major drug target genes include rpoB for RIF and katG, inhA, and ahpC for INH. To determine the frequency and distribution of mycobacterial mutations in these genes, we sequenced specific genes of M. tuberculosis that are associated with resistance to RIF and INH in 157 phenotypic MDR isolates. At the same time, RD105 DTM-PCR and 15 loci MIRU-VNTR were performed to demonstrate the genetic lineage. It was shown that the Beijing genotype was predominant (84.1%) among these strains. The results also showed mutations within the 81 bp core region of rpoB in 93.6% of strains and mutations in a structural gene (katG) and two regulatory regions (the promoter of inhA and intergenic region of oxyR-ahpC) were shown in 88.5% of phenotypic MDR isolates. There were no significant differences in codon mutations between the Beijing and non-Beijing genotypes, as well as the clustered and no-clustered strains. The most prevalent mutations involved in RIF and INH were Ser531Leu in rpoB (55.4%) and Ser315Thr in KatG (56.1%), respectively. There was no significant difference in RIF and INH resistance between MDR-TB and other drug-resistant tuberculosis (DR-TB). The results demonstrated that some MDR-TB patients are predicted to have recent transmission.

Characterization of Staphylococcus aureus isolated from patients with burns in a regional burn center, Southeastern China.

BACKGROUND: S.aureus is a predominant pathogen that causes infection in critically ill patients, but little information exists regarding the characterization of S. aureus from different sources in burn patients in southeastern China. METHODS: We enrolled 125 patients with S. aureus infection in burns center between Jan 2014 and Dec 2015. S. aureus isolates were characterized by antimicrobial susceptibility test, toxin gene detection, and molecular typing with multilocus sequence type, staphylococcal protein A (spa) type, and staphylococcal cassette chromosome mec (SCCmec) type. RESULTS: Sixty-eight MRSA were isolated from SSTI and 31 from non-SSTI patients, respectively. Overall, the drug-resistant ability of S. aureus isolated from SSTI was higher than that from non-SSTI groups. SCCmecIII-CC239-t030 was the most common clone (38 from SSTIs, and 8 from non-SSTIs). Seg was the most common enterotoxin gene (21 from SSTIs and 33 from non-SSTIs). Isolates from SSTIs was more likely to carry seb (P = 0.04), while those from non-SSTIs tended to carry sea and seg (P = 0.002 and 0.01, respectively). Although isolates carried four hemolysin genes, there was no significant difference between them (P > 0.05). CONCLUSION: SCCmecIII-CC239-t030 was the most common clone in Jiangxi burns center, China. The molecular characterization of S. aureus was quite different between SSTI and non-SSTI groups.

Variable-number tandem repeat markers for Mycobacterium intracellulare genotyping: comparison to the 16S rRNA gene sequencing.

INTRODUCTION: Characterizing Mycobacterium intracellulare responsible for nontuberculous mycobacterial (NTM) infections may aid in controlling outbreaks. This study aimed to compare 16S ribosomal ribonucleic acid (rRNA) sequencing and variable-number tandem repeat (VNTR) genotyping of M. intracellulare strains isolated from clinical samples, and to characterize VNTR clusters associated with NTM infections or cavity formation. METHODOLOGY: Sputum samples were obtained from 77 HIV-negative patients with pulmonary disease between 2009 and 2013. One M. intracellulare strain was isolated from each patient and genotyped using 16S rRNA and eight loci VNTR sequencing. RESULTS: Single nucleotide polymorphism (SNP) genotyping identified seven point mutations at nucleotide positions 101, 178, 190, 252, 382, 443, and 490 in 16S rRNA, and four SNP patterns were identified: type 1 (16 strains), 2 (41 strains), 3 (11 strains), and 4 (1 strain); 5 strains had unique SNP patterns. VNTR genotyping identified VNTR12 as the most discriminating marker (allelic diversity 0.692). VNTR3 was the most homogeneous marker (allelic diversity 0.518), but each locus had high discriminating ability. The 77 strains were clustered according to the unpaired group method using arithmetic averages: cluster 1 (17 strains), 2 (43 strains), 3 (9 strains), and 4 (4 strains); 4strains had unique SNP patterns. Overall, over 90% strains were matched to similar SNP and VNTR groupings. VNTR clusters were associated with NTM infection (p =0.007) and presence of a cavity (p =0.042). Both methods distinguished four subtypes of M. intracellulare, which corresponded. CONCLUSIONS: VNTRs may represent an effective, user-friendly, low-cost typing technique.

Drug-resistance dynamics of Staphylococcus aureus between 2008 and 2014 at a tertiary teaching hospital, Jiangxi Province, China.

BACKGROUND: To understand the relationship between the Staphylococcus aureus infection rate and the reasonable usage of antibiotics, which will help in the effective control of MRSA infection. METHODS: All data were obtained by the application of the nosocomial infection surveillance network. Drug resistance, departmental sources, and isolated sites as well as infection rate variations of S. aureus were analyzed in the 7-year period in key departments. RESULTS: Between 2008 and 2014, 2525 strains of S. aureus isolates, mainly from sputum, skin/soft tissue, bloodstreams were collected from several hospital departments including respiratory, burn, brain surgery, orthopedics, ICU, and emergency. During these periods, the resistance rate of S. aureus to most drugs, including oxacillin, tetracycline, erythromycin, clindamycin, gentamicin, and ciprofloxacin, showed a tendency to decrease. The resistance to sulphamethoxazole/trimethoprim showed the opposite trend (P = 0.075) and there were no S. aureus strains resistant to linezolid and vancomycin. The MRSA infection rate was different across crucial hospital departments, with the burns department and ICU maintaining a high infection level. Over the 7-year period, both the brain surgery and the emergency departments had an expected upward trend (P < 0.05), while the orthopedic department showed a clear downward trend (P < 0.05) in MRSA infection rate. CONCLUSION: Hospitals should continue to maintain the current pattern of antibiotic administration, while more effective measures should be taken to reduce the high MRSA infection rate in some important hospital departments.