Objective: To investigate the prevalence of undernutrition and its associated factors among left behind and non left behind primary and secondary school students in the Nutrition Improvement Program for Rural Compulsory Education Students (NIPRCES) areas of central and western China, so as to provide evidence for improving the nutritional status of children and adolescents. Methods: A survey was conducted among 123 782 students selected by random cluster sampling method in grades 3-9 from NIPRCES in central (Hebei, Shanxi, Heilongjiang, Jilin, Anhui, Jiangxi, Henan, Hunan, Hubei, and Hainan) and western (Gansu, Guangxi, Inner Mongolia, Ningxia, Tibet, Shaanxi, Guizhou, Sichuan, Xinjiang, the Xinjiang Production and Construction Corps, Yunnan, Qinghai, and Chongqing) China in 2023. Anthropometric measurements and questionnaires were used to assess nutritional and dietary status. The prevalence of undernutrition was compared between left behind and non left behind students by Chi square test, and associated factors were analyzed by three level Logistic mixed effects model. Results: The prevalence of undernutrition was 8.5% (4 326) in left behind students and 8.1% (5 905) in non left behind students. Three level Logistic mixed effect model analysis showed that whether left behind or non left behind, the undernutrition rates of primary and secondary students in western regions were higher than those of students in central regions [ OR (95% CI )=1.72(1.57-1.87),2.25(2.07- 2.43 )]; the undernutrition risk was lower for those whose fathers had a cultural level of high school or above [ OR (95% CI )=0.69(0.62-0.77),0.90(0.82-0.98)] or junior high school [ OR (95% CI )=0.72(0.66-0.79),0.92(0.85-0.99)] compared to those with primary school or below; picky eating or selective eating increased the risk of undernutrition [ OR (95% CI )=2.36(2.07-2.68),2.28(2.04-2.55)], and primary and secondary school students without nutritional content in health education classes had higher rates of undernutrition [ OR (95% CI )=1.12(1.03-1.23),1.09(1.01-1.17)](all P <0.05). Conclusion The prevalence of undernutrition is slightly higher in left behind primary and secondary students than in non left behind primary and secondary students in central and western NIPRCES areas, with variations across different characteristics.

Objective To gain insights into the biological characteristics of different populations of Culex tritaeniorhynchus within and around the Yellow Sea wetland from the perspective of the occurrence of resistance, we investigated the levels of resistance to deltamethrin and kdr gene mutation in the wetland and its peripheral areas. Methods Specimens were collected from Cx. tritaeniorhynchus populations at two monitoring sites in the Rare Bird National Nature Reserve and Tiaozi Ni Wetland Scenic Area, and also from two populations in Yancheng City and the Liuhe District of Nanjing, and the resistance of these mosquitoes to deltamethrin was determined using the CDC biotest bottle method. For each concentration of deltamethrin assessed, a random subset of exposed specimens was selected for amplification of the kdr gene fragment, followed by Sanger sequencing to identify and analyze resistance-associated mutations. Results The LC50 levels of deltamethrin among mosquitoes from the four populations in Luhe, Yancheng, the Rare Bird National Nature Reserve and the Tiaozi Ni Wetland Scenic Area were 2.048 5, 7.798 2, 3.473 3, and 17.695 5 mg/mL, respectively, with corresponding concentrations of deltamethrin ranging from 0.005 to 5.000,0.050 to 50.000,0.050 to 25.000 and 0.050 to 50.000 mg/mL, respectively. Furthermore, the ranges of the KT50 values were 11.76-107.43, 67.05-216.30,29.77-107.43 and 28.40-329.51 min; the 1-h knockdown rates were 34.58%-99.15%, 9.52%-43.80%, 55.09%-73.01%, and 10.09%-68.07%; and the 24-h mortality rates were 12.15%-67.52%,9.52%-79.56%,13.17%-82.21%, and 11.01%-78.99%, respectively. With respect to kdr gene mutation, we assayed a total of 63,70,59, and 57 mosquitoes for the four populations, for which we detected L1014F mutation frequencies of 14.29%, 35.00%, 20.34%, and 31.58%, respectively, with a majority of these mutations being heterozygous for resistance. In addition, five adult mosquitoes were identified has having synonymous mutations at site 1011[i. e. , AAT(asparagine)mutation to AAC(asparagine)]. Conclusions Our findings revealed the clear resistance of Cx. tritaeniorhynchus to deltamethrin in the Yancheng region of the Yellow Sea wetland, and the resistance phenotype and kdr frequency of Cx. tritaeniorhynchus in the wetland environment were comparable to those of Cx. tritaeniorhynchus in the wetland environment, thereby indicating that the resistance of different populations of Cx. tritaeniorhynchus was homogeneous under the pressure of different insecticide selection within and around the wetland. However, the underlying mechanisms need to be further studied.

Objective To explore the association between dynamic indexes of maternal progesterone in early pregnancy and the average level and growth rate of fetal head circumference(HC)in mid-and late pregnancy.Methods This study adopted a retrospective cohort design and included 255 singleton pregnant women in the maternal and infant cohort of The First Affiliated Hospital of Xi'an Jiaotong University from January 2015 to December 2024.The progesterone levels of their early venous blood were detected and divided into two groups of progesterone trajectories,namely,fluctuating type and increasing type,by morphology.The dynamic indicators of progesterone in early pregnancy were constructed:cumulative dynamic deviation index in the first trimester(CDDI-P1T),gestational age at progesterone peak(GA-PP),and maximal relative progesterone decline in the first trimester(MRD-P1T).The average head circumference level and linear growth rate of the fetuses in the middle and late pregnancy were calculated.Generalized linear regression(GLM)was used to analyze the linear association between progesterone dynamic indicators and head circumference development.The key gestational weeks of progesterone affecting fetal head development were explored by linear regression of gestational weeks.Ordinary least squares(OLS)regression and restricted cubic spline(RCS)plots were used to draw the nonlinear association between progesterone dynamic indicators and head circumference.Results Among the 255 pregnant women included,92.5％of the progesterone trajectories in early pregnancy were fluctuating,and 7.5％were increasing.The growth rates of the increasing progesterone trajectory group were higher in the second and third trimesters than in the fluctuating group,but the differences were not statistically significant(all P＞0.05).GLM analysis showed that for every 1 unit increase in CDDI-P1T,the head circumference in the middle and late pregnancy increased significantly by 1.574 cm and 1.193 cm(Z=3.714,2.885,P＜0.01).The delay of GA-PP was negatively correlated with the head circumference in the middle pregnancy(β=-0.190 cm,95％CI:-0.339--0.041,P=0.010)but positively correlated with the head circumference growth rate in the late pregnancy(β=0.022 cm/week,95％CI:0.003-0.041,P=0.025).A 10％decrease in the decline of CDDI-P1T increased the head circumference in the middle pregnancy by 0.200 cm(95％CI:0.016-0.384,P=0.033),and a 100％decrease in the decline increased the head circumference growth rate in the late pregnancy by 0.201 cm/week(95％CI:0.002-0.399,P=0.048).The analysis of the key time window showed that for every 20 nmol/L increase in progesterone during 9.5-13 weeks of pregnancy,the mid-term head circumference increased by 0.035-0.166 cm(Z=2.452-3.517,allP＜0.05),and the late-term head circumference increased by 0.767 cm during 9-13 weeks of pregnancy(Z=2.452-3.517,all P＜0.05).When progesterone increased during 9.5-10.5 weeks of pregnancy,the growth rate of mid-term head circumference increased by 0.013-0.023 cm/week(Z=2.074-2.243,all P＜0.01).When progesterone increased during 8.5-10.5 weeks of pregnancy,the growth rate of late-term head circumference increased by 0.010-0.026 cm/week(Z=2.061-3.137,all P＜0.05).Conclusion Progesterone dynamic index is a new sensitive tool for evaluating fetal head circumference development.There is a stage-specific window period for progesterone regulation.9.5-13 weeks of pregnancy is the critical period for progesterone to affect head circumference growth,and 9.5-10.5 weeks of pregnancy is the core window for regulating the growth rate of head circumference.Therefore,it is necessary to combine progesterone dynamic index and time window for individualized intervention to promote the transformation of prenatal care from pregnancy maintenance to eugenics intervention.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objective To develop an enteral nutrition delivery device for nasal feeding patients to relieve gastrointestinal discomfort during enteral nutrition therapy and solve the problems in heating,quality preservation and constant temperature maintenance of the solution.Methods The enteral nutrition delivery device was mainly composed of a nasal feeding container,a fixing frame,a limiting trough,a heating wire,a temperature control unit and a speed control unit.The heating wire and temperature and speed control units were combined to facilitate the nasogastric solution in the container to be delivered to the patient's stomach and intestines at a constant temperature and a uniform speed.The device developed had its shell made of 304 waterproof stainless steel and the nasal feeding container made of 05-polypropylene.Results The device developed realized constant-temperature and uniform-speed delivery and auto cleaning,and could reduced effectively gastrointestinal adverse reactions during nasal feeding.Conclusion The device developed gains advantages in easy operation and autonomous feeding,and thus is worth promoting for nasal feeding patients clinically.[Chinese Medical Equipment Journal,2025,46(2):108-111]

Objective To explore the association between dynamic indexes of maternal progesterone in early pregnancy and the average level and growth rate of fetal head circumference(HC)in mid-and late pregnancy.Methods This study adopted a retrospective cohort design and included 255 singleton pregnant women in the maternal and infant cohort of The First Affiliated Hospital of Xi'an Jiaotong University from January 2015 to December 2024.The progesterone levels of their early venous blood were detected and divided into two groups of progesterone trajectories,namely,fluctuating type and increasing type,by morphology.The dynamic indicators of progesterone in early pregnancy were constructed:cumulative dynamic deviation index in the first trimester(CDDI-P1T),gestational age at progesterone peak(GA-PP),and maximal relative progesterone decline in the first trimester(MRD-P1T).The average head circumference level and linear growth rate of the fetuses in the middle and late pregnancy were calculated.Generalized linear regression(GLM)was used to analyze the linear association between progesterone dynamic indicators and head circumference development.The key gestational weeks of progesterone affecting fetal head development were explored by linear regression of gestational weeks.Ordinary least squares(OLS)regression and restricted cubic spline(RCS)plots were used to draw the nonlinear association between progesterone dynamic indicators and head circumference.Results Among the 255 pregnant women included,92.5％of the progesterone trajectories in early pregnancy were fluctuating,and 7.5％were increasing.The growth rates of the increasing progesterone trajectory group were higher in the second and third trimesters than in the fluctuating group,but the differences were not statistically significant(all P＞0.05).GLM analysis showed that for every 1 unit increase in CDDI-P1T,the head circumference in the middle and late pregnancy increased significantly by 1.574 cm and 1.193 cm(Z=3.714,2.885,P＜0.01).The delay of GA-PP was negatively correlated with the head circumference in the middle pregnancy(β=-0.190 cm,95％CI:-0.339--0.041,P=0.010)but positively correlated with the head circumference growth rate in the late pregnancy(β=0.022 cm/week,95％CI:0.003-0.041,P=0.025).A 10％decrease in the decline of CDDI-P1T increased the head circumference in the middle pregnancy by 0.200 cm(95％CI:0.016-0.384,P=0.033),and a 100％decrease in the decline increased the head circumference growth rate in the late pregnancy by 0.201 cm/week(95％CI:0.002-0.399,P=0.048).The analysis of the key time window showed that for every 20 nmol/L increase in progesterone during 9.5-13 weeks of pregnancy,the mid-term head circumference increased by 0.035-0.166 cm(Z=2.452-3.517,allP＜0.05),and the late-term head circumference increased by 0.767 cm during 9-13 weeks of pregnancy(Z=2.452-3.517,all P＜0.05).When progesterone increased during 9.5-10.5 weeks of pregnancy,the growth rate of mid-term head circumference increased by 0.013-0.023 cm/week(Z=2.074-2.243,all P＜0.01).When progesterone increased during 8.5-10.5 weeks of pregnancy,the growth rate of late-term head circumference increased by 0.010-0.026 cm/week(Z=2.061-3.137,all P＜0.05).Conclusion Progesterone dynamic index is a new sensitive tool for evaluating fetal head circumference development.There is a stage-specific window period for progesterone regulation.9.5-13 weeks of pregnancy is the critical period for progesterone to affect head circumference growth,and 9.5-10.5 weeks of pregnancy is the core window for regulating the growth rate of head circumference.Therefore,it is necessary to combine progesterone dynamic index and time window for individualized intervention to promote the transformation of prenatal care from pregnancy maintenance to eugenics intervention.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.