Peptidoglycan biosynthesis-associated enzymatic kinetic characteristics and ß-lactam antibiotic inhibitory effects of different Streptococcus pneumoniae penicillin-binding proteins.

Penicillin-binding proteins (PBPs) include transpeptidases, carboxypeptidases, and endopeptidases for biosynthesis of peptidoglycans in the cell wall to maintain bacterial morphology and survival in the environment. Streptococcus pneumoniae expresses six PBPs, but their enzymatic kinetic characteristics and inhibitory effects on different ß-lactam antibiotics remain poorly understood. In this study, all the six recombinant PBPs of S. pneumoniae displayed transpeptidase activity with different substrate affinities (Km = 1.56-9.11 mM) in a concentration-dependent manner, and rPBP3 showed a greater catalytic efficiency (Kcat = 2.38 s-1) than the other rPBPs (Kcat = 3.20-7.49 × 10-2 s-1). However, only rPBP3 was identified as a carboxypeptidase (Km = 8.57 mM and Kcat = 2.57 s-1). None of the rPBPs exhibited endopeptidase activity. Penicillin and cefotaxime inhibited the transpeptidase and carboxypeptidase activity of all the rPBPs but imipenem did not inhibited the enzymatic activities of rPBP3. Except for the lack of binding of imipenem to rPBP3, penicillin, cefotaxime, and imipenem bound to all the other rPBPs (KD = 3.71-9.35 × 10-4 M). Sublethal concentrations of penicillin, cefotaxime, and imipenem induced a decrease of pneumococcal pbps-mRNA levels (p < 0.05). These results indicated that all six PBPs of S. pneumoniae are transpeptidases, while only PBP3 is a carboxypeptidase. Imipenem has no inhibitory effect on pneumococcal PBP3. The pneumococcal genes for encoding endopeptidases remain to be determined.

Survival status of HIV/AIDS patients aged ≥ 50 years old receiving antiretroviral therapy in Shanxi, 2011-2019 / 中国热带医学

@#Abstract: Objective　To analyze the survival status of HIV/AIDS patients aged above 50 years receiving antiviral therapy (ART) in Shanxi Province from 2011 to 2019, and to provide evidence for further improvement of antiviral therapy. Methods　Basic information and follow-up information of HIV/AIDS patients aged above 50 years who first received HIV/AIDS antiviral therapy in Shanxi Province from 2011 to 2019 were collected. Excel database was established and SPSS23.0 software was used for analysis. Retrospective cohort study was conducted. Cox proportional risk regression model was used to analyze the factors influencing survival time. Results　A total of 1 183 subjects were included, of which 172 died, including 84(48.84%) from other causes, 74(43.02%) AIDS-related death and 14 (8.14%) from accidents, suicides and undetermined deaths. Setting AIDS-related deaths as an outcome event, life table analysis showed that the cumulative survival rates at 1, 3, 5, 7 and 9 years after receiving ART were 96.61%, 93.59%, 90.35%, 87.57% and 83.44%, respectively. Multivariate Cox proportional risk model analysis showed that the risk of death in patients aged 60-<70 years group and over 70 age group was 2.53 times (95%CI: 1.51-4.23) and 3.59 times (95%CI: 1.74-7.40) for patients aged the 50-<60 group , respectively. The risk of death in patients with baseline CD4+T lymphocyte (CD4) counts of ≥200/mm3, 50-<200 /mm3 was 0.22 times (95%CI: 0.12-0.41) and 0.37 times (95%CI: 0.21-0.67) for patients with CD4+T lymphocyte counts of <50/mm3. The risk of death in patients with opportunistic infections at baseline was 1.99 times (95%CI: 1.16-3.39) for patients without baseline opportunistic infections. Conclusions　The survival rate of HIV/AIDS patients aged above 50 who received antiviral therapy (ART) in Shanxi Province from 2011 to 2019 was relatively high. To further improve the quality of antiviral treatment in our province, the strategy of "early detection and early treatment" should be continued and improved in the future, and information collection of specific causes of non-AIDS-related deaths among this population should be further strengthened.

Leptospirosis is an invasive infectious and systemic inflammatory disease.

Pathogenic Leptospira species are the causative agents of leptospirosis, a world-spreading zoonotic infectious disease. The pathogens possess a powerful invasiveness by invading human body through mucosal/skin barriers, rapid entry into bloodstream to cause septicemia, diffusion from bloodstream into internal organs and tissues to cause aggravation of disease, and discharge from urine through renal tubules to form natural infectious sources. Leptospirosis patients present severe inflammatory symptoms such as high fever, myalgia and lymphadenectasis. Hemorrhage and jaundice are the pathological features of this disease. Previous studies revealed that some outer membrane proteins of Leptospira interrogans, the most important pathogenic Leptospira species, acted as adherence factors to binding to receptor molecules (fibronectin, laminin and collagens) in extracellular matrix of host cells. Collagenase, metallopeptidases and endoflagellum contributed to the invasiveness of L. interrogans. Except for lipopolysaccharide, multiple hemolysins of L. interrogans displayed a powerful ability to induce pro-inflammatory cytokines and hepatocyte apoptosis. vWA and platelet activating factor acetylhydrolase-like proteins from L. interrogans could induce severe pulmonary hemorrhage in mice. L. interrogans utilized cellular endocytic recycling and vesicular transport systems for intracellular migration and transcellular transport. All the research achievements are helpful for further understanding the virulence of pathogenic Leptospira species and pathogenesis of leptospirosis.

Sublethal ß-lactam antibiotics induce PhpP phosphatase expression and StkP kinase phosphorylation in PBP-independent ß-lactam antibiotic resistance of Streptococcus pneumoniae.

StkP and PhpP of Streptococcus pneumoniae have been confirmed to compose a signaling couple, in which the former is a serine/threonine (Ser/Thr) kinase while the latter was annotated as a phosphotase. StkP has been reported to be involved in penicillin-binding protein (PBP)-independent penicillin resistance of S. pneumoniae. However, the enzymatic characterization of PhpP and the role of PhpP in StkP-PhpP couple remain poorly understood. Here we showed that 1/4 minimal inhibitory concentration (MIC) of penicillin (PCN) or cefotaxime (CTX), the representatives of ß-lactam antibiotics, could induce the expression of stkP and phpP genes and phosphorylation of StkP in PCN/CTX-sensitive strain ATCC6306 and three isolates of S. pneumoniae (MICs: 0.02-0.5 µg/ml). The product of phpP gene hydrolyzed PP2C type Ser/Thr phosphotase-specific RRA (pT)VA phosphopeptide substrate with the Km and Kcat values of 277.35 µmoL/L and 0.71 S-1, and the hydrolytic activity was blocked by sodium fluoride, a PP2C type Ser/Thr phosphatase inhibitor. The phosphorylation levels of StkP in the four phpP gene-knockout (ΔphpP) mutants were significantly higher than that in the wild-type strains. In particular, the MICs of PCN and CTX against the ΔphpP mutants were significantly elevated as 4-16 µg/ml. Therefore, our findings confirmed that sublethal PCN and CTX act as environmental inducers to cause the increase of phpP and stkP gene expression and StkP phosphorylation. PhpP is a PP2C type Ser/Thr protein phosphatase responsible for dephosphorylation of StkP. Knockout of the phpP gene results in a high level of StkP phosphorylation and PBP-independent PCN/CTX resistance of S. pneumoniae.

Molecular Characterization and Correlation with ß-lactam Resistance of Streptococcus pneumonia Isolates in Hangzhou, China.

Penicillin-binding proteins (PBPs) are the target of ß-lactam antibiotics (the major treatment for Streptococcus pneumoniae infections), and mutations in PBPs are considered as a primary mechanism for the development of ß-lactam resistance in S. pneumoniae. This study was conducted to investigate the mutations in the PBPs of clinical S. pneumoniae isolates in Hangzhou, China, in correlation with ß-lactam resistance. Results showed that 19F was the predominant serotype (7/27) and 14 of the S. pneumoniae isolates were resistant to both penicillin G and cephalosporin. Genotyping results suggested that ß-lactam-resistant isolates primarily exhibited single-site mutations in both the STMK and SRNVP motifs of pbp1a in combination with double-site mutations in the STMK motif of pbp2x, which might be the primary mechanisms underlying the ß-lactam resistance of the isolates in this study.

Usefulness of interferon-γ release assay for the diagnosis of sputum smear-negative pulmonary and extra-pulmonary TB in Zhejiang Province, China.

BACKGROUND: Quick diagnosis of smear-negative pulmonary tuberculosis (TB) and extra-pulmonary TB are urgently needed in clinical diagnosis. Our research aims to investigate the usefulness of the interferon-γ release assay (IGRA) for the diagnosis of smear-negative pulmonary and extra-pulmonary TB. METHODS: We performed TB antibody and TB-IGRA tests on 389 pulmonary TB patients (including 120 smear-positive pulmonary TB patients and 269 smear-negative pulmonary TB patients), 113 extra-pulmonary TB patients, 81 patients with other pulmonary diseases and 100 healthy controls. Blood samples for the TB-Ab test and the TB-IGRA were collected, processed, and interpreted according to the manufacturer's protocol. RESULTS: The detection ratio of smear-positive pulmonary TB patients and smear-negative pulmonary TB patients were 90.8% (109 of 120) and 89.6% (241 of 269), respectively. There was no statistically significant difference of its performance between these two sample sets (P > 0.05). The detection ratio of positive TB patients and extra-pulmonary TB patients were 90.0% (350 of 389) and 87.6% (99 of 113), respectively, which was not significantly different (P > 0.05). CONCLUSIONS: In this work, the total detection ratio using TB-IGRA was 89.4%, therefore TB-IGRA has diagnostic values in smear-negative pulmonary TB and extra-pulmonary TB diagnosis.

The complete mitogenome and phylogenetic analysis of Acrossocheilus jishouensis (Osteichthyes: Cyprinidae).

Acrossocheilus jishouensis is an endemic south China stream-dwelling cyprinid species. Its complete mitochondrial genome is 16,587 bp in length, consisting of 13 protein-coding genes, 22 tRNA genes (ranging from 67 bp in tRNACys to 76 bp in tRNALeu and tRNALys ), two rRNA genes (956 bp in 12S rRNA and 1673 bp in 16S rRNA), and one control region (942 bp). Its overall base composition is A: 31.2%, C: 27.6%, G: 16.2%, and T: 25.1%. The complete mitogenome of the Chinese barred species of Cpynidae could provide a basic data for further phylogenetics analysis.

The complete mitogenome and phylogenetic analysis of Acrossocheilus beijiangensis (osteichthyes: Cyprinidae).

Acorssocheilus beijiangensis is an endemic south China stream-dwelling cyprinid species. Its complete mitochondrial genome is 16,596 bp in length, consisting of 13 protein-coding genes, 22 tRNA genes (ranging from 67 bp in tRNACys to 76 bp in tRNALeu and tRNALys ), two rRNA genes (959 bp in 12S rRNA and 1683 bp in 16S rRNA), and one control region (937 bp). Its overall base composition is A: 31.1%, C: 27.9%, G: 16.2%, and T: 124.8%. The complete mitogenome of the Chinese barred species of Cyprinidae could provide a basic data for further phylogenetics analysis.

Complete mitochondrial genome of Gnathopogon taeniellus (Cypriniformes: Cyprinidae).

The complete mitochondrial genome of Gnathopogon taeniellus was first determined in this study. It is 16,596 bp in length, contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and one control region in the typical vertebrate gene order and transcriptional direction. There are total of 29 bp short overlaps and 34 bp non-coding intergenic spacers were found in the mitogenome. Overall nucleotide base composition of light strand is 29.3% A, 25.8% C, 17.9% G and 27.0% T. Two start codons (ATG and GTG) and two stop codons (TAG and TAA/T) were used in the protein-coding genes. The origin of light strand replication (OL) was identified between tRNA(Asn) and tRNA(Cys) genes and could fold a hairpin structure. The nucleotide composition of control region is 31.8% A, 20.9% C, 14.0% G and 33.3% T.

Mitochondrial phylogeny of Chinese barred species of the cyprinid genus Acrossocheilus Oshima, 1919 (Teleostei: Cypriniformes) and its taxonomic implications.

Sequences from the mitochondrial control region of 14 putative species of Acrossocheilus (Cyprinidae) were examined to elucidate phylogenetic relationships within species of the barred group in that genus. Phylogenetic reconstructions were generated using three tree-building methods: maximum parsimony, maximum likelihood, and Bayesian inference. The resultant phylogenies were consistent with monophyly of the majority of the morphologically recognized species. However, mitochondrial DNA sequence evidence is incongruent with monophyly of A. fasciatus, as currently conceived. This species occurs only in the upper Qiantang-Jiang basin in Zhejiang and Anhui provinces, and coastal rivers in the Zhejiang Province. The species formerly recognized as A. paradoxus from Zhejiang Province is A. fasciatus. The specimens previously reported as A. fasciatus from river basins in Fujian Province are misidentified A. wuyiensis. The barred group of Acrossocheilus is shown to be polyphyletic. Acrossocheilus is restricted to the barred species here placed in "Clade II," containing A. paradoxus and relatives. Separate generic status is recommended for A. monticola and for A. longipinnis and their closest relatives, although more information on phylogenetic relationships based on multiple genes is required to develop robust phylogenetic hypotheses and diagnoses. Masticbarbus Tang, 1942 is available for A. longipinnis and three allied species (A. iridescens, A. microstomus and A. lamus).

Human papillomavirus prevalence and type-distribution among women in Zhejiang Province, Southeast China: a cross-sectional study.

BACKGROUND: Human papillomavirus (HPV) infection is the main etiological factor for cervical cancer and premalignant lesions of the cervix. The purposes of the present study were to determine the prevalence of type-specific HPV infections and the association of different HPV types with cervical dysplasia among women in Zhejiang province, Southeast China. METHODS: A total of 15,267 women presenting to a gynaecological outpatient clinic were enrolled in this study. Women were screened for HPV in addition to routine cervical cytology testing. Microarray hybridization and liquid-based cytology tests were used to detect HPV genotypes and cervical cytology, respectively. RESULTS: Based on the population attending a gynaecological outpatient clinic, overall prevalence of any 23 HPV type was 22.8% and multiple HPV infection was found in 4.0% of all the outpatients. HPV prevalence showed bimodal age distribution, with a peak (55.7%) at the ≤20 age group and a second one (35.5%) at >60 age group. In total samples, the five most frequent types were HPV 16 (4.4%), 58 (2.9%), 52 (2.7%), 33 (2.2%) and 11 (1.9%). Overall HPV prevalence increased with the severity of the cytologic result. Analysis through crude odds ratios (ORs) revealed that the cervical lesion risk of HPV-infected women increased to about 26-fold of uninfected women (OR 26.1, 95% CI 22.4 to 30.3). The five most risky HPV types associated with abnormal cytology were HPV 73, 16, 82, 45 and 51. CONCLUSIONS: This study provided baseline data on HPV prevalence in women attending a gynecological outpatient clinic in Zhejiang province. Our data will supply guidance for the primary screening and vaccination program for cervical cancer in this area.

[Detected of associated contagious parameters of blood recipients before transfusion and their clinical significance].

OBJECTIVE: To investigate the significance in prevention of nosocomial infection of the testing of the associated contagious parameters of blood recipients before transfusion. METHODS: A retrospective analysis was adopted, 44 968 pre-transfusion patients were tested the serum hepatitis B virus surface antigen (HBsAg), antibody against hepatitis C virus (anti-HCV), antibody against T. pallidum (anti-TP) and antibody against human immunodeficiency virus(anti-HIV). RESULTS: The total positive rate was 22.41%. Positive rate of HBsAg, anti-HCV and anti-TP were 20. 67% (9294/44 968) , 0.33% (148/ 44 968) and 1.65% (9741/44968), respectively; anti-HIV was positive in 39 patients, 23 cases coinfection of the other three indicators at least one positive in 39 cases of anti-HIV-positive blood recipients, of which was mostly observed T. pallidum; co-infection of HBV, HCV and/or TP were 117 cases, and were mostly observed between HBV and HCV, HCV and TP; for HBV infection the department of digestive medicine was prevalent(Chi2>or=83.0, P <0.01). CONCLUSION: Part of blood recipients before admission had been infected with a contagious disease. The testing of the associated contagious parameters of blood recipients before transfusion is not only useful for both of the hospital and the patients, but also more important to ensure safe blood transfusion, decrease medial dissatisfaction and to prevent nosocomial infection.

[The expression of protein kinase C and the regulatory effect of nerve growth factor in the lung and the visceral sensory afferent system of asthmatic guinea pigs].

OBJECTIVE: To explore the expression of protein kinase C (PKC) and the regulatory effect of nerve growth factor (NGF) in the lung and the visceral sensory afferent system (C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord) of asthmatic guinea pigs. METHODS: Forty guinea pigs were divided to four groups, a saline control group (group A, n = 8), a provocation alone control group (group B, n = 8), an asthmatic group (group C, n = 12) and an anti-NGF group (group D, n = 12). The alterations of PKC immunoreactivity were investigated by means of immunohistochemistry in the C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of all groups. The expressions of NGF and PKC were investigated by Western blot in the lung, C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of all groups. The results were analyzed by the Luzex-F real time image analysis system and the gel imaging analysis system respectively. RESULTS: (1) Immunohistochemistry results: The absorbency (A) values of PKC were 0.102 +/- 0.009, 0.113 +/- 0.009, 0.106 +/- 0.005 and 0.116 +/- 0.007 in the C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of group A and group B respectively. There was no significant difference between group A and group B (P > 0.05). The A values of PKC were 0.215 +/- 0.014 and 0.176 +/- 0.010 respectively in the C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of group C, which were significantly different compared with group A (P < 0.01). The A values of PKC were 0.140 +/- 0.008 and 0.130 +/- 0.011 respectively in the C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of group D, which were significantly different compared with group C (P < 0.01). (2) Western blot results: Compared with group A (the relative A values were 0.51 +/- 0.02, 0.43 +/- 0.01 and 0.92 +/- 0.02 respectively) and group B, the expression of PKC (the relative A values were 1.51 +/- 0.01, 1.40 +/- 0.03 and 2.22 +/- 0.02 respectively) increased markedly in the lung, C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of group C; however, the expression of PKC of group D (the relative A values were 0.80 +/- 0.03, 0.83 +/- 0.01 and 1.12 +/- 0.02 respectively) decreased markedly in comparison with group C. CONCLUSION: The present results indicate that PKC might be involved in the pathogenesis of bronchial asthma, and NGF can upregulate the expression of PKC.