Prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae among healthy children under 5 years of age in Hainan Province, China.

BACKGROUND: The thirteen-valent pneumococcal conjugate vaccine (PCV13) is not included in the national immunization program and is administered voluntarily with informed consent in China. In preparation for assessing the impact of pilot introduction in Hainan Province, we conducted a carriage study among children under 5 years of age from four locations in Hainan Province, China. METHODS: From March to June 2022, nasopharyngeal (NP) swabs, collected from healthy children aged younger than 59 months who lived in the 4 different locations (Haikou, Wanning, Baisha and Qiongzhong) in Hainan Province, were tested for pneumococcus using conventional culture. Pneumococcal isolates were serotyped using the Quellung reaction. Risk factors associated with pneumococcal colonization were assessed using univariate analysis and multivariable logistic regression adjusting for age, daycare attendance and other factors. RESULTS: Pneumococcus was isolated in 710 (30.4%) of the 2333 children enrolled. Of 737 pneumococci, 29 serotypes were identified; 60.9% were PCV13 serotypes; the most common vaccine serotypes were 6B (20.4%), 19F (13.0%), 6A (11.9%) and 23F (6.1%); and the most common nonvaccine serotypes were 23A (12.9%), 34 (6.1%) and nontypeable (NT) pneumococci (5.6%). Children vaccinated with PCV13 had lower carriage (17.7% vs 32.5%; P = 0.0001) and fewer PCV13 serotypes (41.9% vs 62.7%; P = 0.0017) compared to unimmunized children. After adjustment, NP carriage was higher among children attending daycare (aOR = 2.3, 95% CI: 1.7-3.2), living in rural areas (aOR = 1.4, 95% CI: 1.1-1.8), living with siblings (aOR = 1.3, 95% CI: 1.0-1.6) and whose mothers had completed senior high/technical secondary school (aOR = 1.5, 95% CI: 1.1-2.0). In contrast, completion of 3-4 doses of PCV13 were associated with a lower carriage rate (aOR = 0.6, 95% CI: 0.4-0.9). CONCLUSIONS: We established the baseline of pneumococcal carriage, serotype distribution and PCV13 immunization rates among healthy children under 5 years of age in Hainan Province, prior to the introduction of PCV13 into the national immunization program. The high proportion of PCV13 serotypes suggests that PCV13 introduction will likely have a substantial impact on pneumococcal carriage in Hainan Province.

Rabies Virus Neutralizing Activity, Safety, and Immunogenicity of Recombinant Human Rabies Antibody Compared with Human Rabies Immunoglobulin in Healthy Adults.

Objective: Preliminary assessment of rabies virus neutralizing activity, safety and immunogenicity of a recombinant human rabies antibody (NM57) compared with human rabies immunoglobulin (HRIG) in Chinese healthy adults. Methods: Subjects were randomly (1:1:1) allocated to Groups A (20 IU/kg NM57), B (40 IU/kg NM57), or C (20 IU/kg HRIG). One injection was given on the day of enrollment. Blood samples were collected on days -7 to 0 (pre-injection), 3, 7, 14, 28, and 42. Adverse events (AEs) and serious AEs (SAEs) were recorded over a period of 42 days after injection. Results: All 60 subjects developed detectable rabies virus neutralizing antibodies (RVNAs) (> 0.05 IU/mL) on days 3, 7, 14, 28, and 42. The RVNA levels peaked on day 3 in all three groups, with a geometric mean concentration (GMC) of 0.2139 IU/mL in Group A, 0.3660 IU/mL in Group B, and 0.1994 IU/mL in Group C. At each follow-up point, the GMC in Group B was significantly higher than that in Groups A and C. The areas under the antibody concentration curve over 0-14 days and 0-42 days in Group B were significantly larger than those in Groups A and C. Fifteen AEs were reported. Except for one grade 2 myalgia in Group C, the other 14 were all grade 1. No SAEs were observed. Conclusion: The rabies virus neutralizing activity of 40 IU/kg NM57 was superior to that of 20 IU/kg NM57 and 20 IU/kg HRIG, and the rabies virus neutralizing activity of 20 IU/kg NM57 and 20 IU/kg HRIG were similar. Safety was comparable between NM57 and HRIG.

Effect of photodynamic inactivation of Escherichia coli by hypericin.

The present study has focused on the effects of hypericin (Hyp) based photodynamic inactivation (PDI) of Escherichia coli (E. coli). To evaluate the efficiency of Hyp based PDI of E. coli, single factor experiments and response surface optimization experiment were conducted to obtain the optimum parameter values (36 µM Hyp, 5.9 J cm-2 light dose: 16.4 mW cm-2, 60 W, 260 s, 590 nm and 68 min incubation time) and finally achieved a 4.1 log CFU mL-1 decrease of E. coli. Cell-Hyp interaction and intracellular reactive oxygen species (ROS) level were detected by fluorescence spectrometric photometer. Data indicated that Hyp possessed a strong ability to bind with cells. In addition, a significant increase was observed in intracellular ROS level after Hyp-based photosensitization treatment. Therefore, Hyp-based photosensitization seems to be a promising method to efficiently inactivate E. coli. It is expected to be a safe, efficient, low cost and practical method which can be applied in the field of food safety.

Prediction of Signal Peptide Cleavage Sites with Subsite-Coupled and Template Matching Fusion Algorithm.

Fast and effective prediction of signal peptides (SP) and their cleavage sites is of great importance in computational biology. The approaches developed to predict signal peptide can be roughly divided into machine learning based, and sliding windows based. In order to further increase the prediction accuracy and coverage of organism for SP cleavage sites, we propose a novel method for predicting SP cleavage sites called Signal-CTF that utilizes machine learning and sliding windows, and is designed for N-termial secretory proteins in a large variety of organisms including human, animal, plant, virus, bacteria, fungi and archaea. Signal-CTF consists of three distinct elements: (1) a subsite-coupled and regularization function with a scaled window of fixed width that selects a set of candidates of possible secretion-cleavable segment for a query secretory protein; (2) a sum fusion system that integrates the outcomes from aligning the cleavage site template sequence with each of the aforementioned candidates in a scaled window of fixed width to determine the best candidate cleavage sites for the query secretory protein; (3) a voting system that identifies the ultimate signal peptide cleavage site among all possible results derived from using scaled windows of different width. When compared with Signal-3L and SignalP 4.0 predictors, the prediction accuracy of Signal-CTF is 4-12 %, 10-25 % higher than that of Signal-3L for human, animal and eukaryote, and SignalP 4.0 for eukaryota, Gram-positive bacteria and Gram-negative bacteria, respectively. Comparing with PRED-SIGNAL and SignalP 4.0 predictors on the 32 archaea secretory proteins of used in Bagos's paper, the prediction accuracy of Signal-CTF is 12.5 %, 25 % higher than that of PRED-SIGNAL and SignalP 4.0, respectively. The predicting results of several long signal peptides show that the Signal-CTF can better predict cleavage sites for long signal peptides than SignalP, Phobius, Philius, SPOCTOPUS, Signal-CF and Signal-3L. These results show that Signal-CTF is more accurate and flexible in predicting signal peptides of different characteristics for many organisms. Signal-CTF is freely available as a web-server at http://darwin2.cbi.utsa.edu/minniweb/index.html.