Objective:To investigate the drug-resistant gene characteristics and core genome characteristics of carbapenem-resistant Enterobacter cloacae (CR-ECL) in rural residents of Weifang City, Shandong Province. Methods:Fecal samples were collected from rural community residents in Weifang City, Shandong Province in 2017. Drug-resistant strains were screened using a carbapenem-resistant enterobacter chromogenic medium. CR-ECL positive strains were acquired via Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry(MALDI-TOFMS) analysis. The antibiotic resistance phenotype of CR-ECL was determined using a microbroth dilution assay. Whole genome sequencing (WGS) and analysis were conducted, along with an examination of the immediate vicinity of the blaNDM gene and phylogenetic analysis of the strains. Results:A total of 628 fecal samples were collected and tested, of which 6 were CR-ECL positive (detection rate 0.96%), all exhibiting multiple drug resistance (MDR) phenotypes. Six CR-ECL strains had four MLST genotypes (ST), all of which carried multiple drug resistance genes ( blaNDM-1, blaNDM-5, etc.) and virulence genes ( acrA, acrB, entB, fepC, etc.). There were mobile genetic elements ISAba125, TN3-IS3000, TN3 and IS5 in the genetic environment surrounding the blaNDM gene. The phylogenetic tree showed that the multi-locus sequence typing of the core genome (cgMLST) was consistent with the single nucleotide polymorphism (SNPs) results. The cgMLST results showed that the allele differences between strains 2BC0101B and 2BC0251B, 2BG0561B and 2BI0221B were 2 and 1, respectively. The SNPs results showed that the above two pairs of bacteria also clustered together. It was found that the strains of chicken fecal samples in the National Center for Biotechnology Information (NCBI) database were located in the center of the evolutionary tree, and the local sequences could be traced back to American human sequences. Conclusion:Multidrug-resistant CR-ECL is detected in rural community residents in Weifang City, Shandong Province.

Objective:To characterize the complete genome sequence and elucidate the structural features of norovirus (NoV) isolate SD20200267.Methods:The viral nucleic acid was extracted from patient samples, followed by amplification and sequencing for genotyping based on the nucleotide sequences. The metagenomic sequencing technology was utilized for whole genome sequencing, and subsequent analysis was performed on the acquired nucleotide sequences.Results:The complete genome sequence of the SD20200267 strain, spanning a total length of 7 465 nucleotides, was successfully obtained. The SD20200267 strain belongs to the GⅡ.12 and GⅡ.P16 genotypes in the VP1 and RdRp regions, respectively. The nucleotide sequence identity of SD20200267 strain with other GⅡ.12[P16] strains ranged from 96.0% to 97.3%, exhibiting 15 amino acid variations. The strain displayed evidence of recombination, with the recombination site located in the overlapping region of ORF1 and ORF2.Conclusions:SD20200267 is classified as a GⅡ.12[P16] strain, and recombination was observed in the overlapping region of ORF1 and ORF2.

Objective:To analyze the surveillance data of population in rabies exposure and post-exposure prophylaxis (PEP) clinics in Shandong province from 2019 to 2023, explore risk factors for exposure, and provide a basis for further standardizing PEP.Methods:Based on surveillance data from the rabies exposure treatment clinic vaccination information system, population, and spatial administrative division data in Shandong province from 2019 to 2023, descriptive epidemiological methods were applied to analyze using SPSS 18.0.Results:The number of individuals receiving post-exposure treatment at PEP clinics in Shandong province from 2019 to 2023 was over 1 million annually and showed an increasing trend year by year, with the highest number of visits occurring from May to August each year. The number of female patients is increasing year by year. The 15-year-old and younger age group accounted for 31.69%-36.86% of clinic visits. Grade Ⅲ exposures accounted for 53.40%, and limbs accounted for approximately 89.81% of exposed areas. Approximately 1.94% is multi site exposure. The main injuring animals were dogs, followed by cats, and the proportion of cats is increasing year by year. The proportion of doctor′s office visitors who self-treated wounds increased from 32.32% to 45.46%, while the proportion of outpatient wound treatment decreased from 76.07% to 66.24%. The whole course vaccination rate after initial exposure is 63.79%. The whole course vaccination rate for the 15-29-year-old age group was lower than that for other age groups. The usage rate of passive immune preparations among grade Ⅲ exposed individuals is 35.66%. From 2019 to 2023, 8 cases of rabies were reported, none of whom received standard post-exposure treatment.Conclusions:The epidemic characteristics and exposure risk of people exposed to suspected rabies animals in Shandong province have changed. It is necessary to pay attention to the female population, the population with low vaccination rate between 15 to 29 years of age, cat bitten people, and carry out continuous monitoring on the exposed population, and timely adjust the prevention and control strategies.

Objective:To investigate the potential source of infection for a cluster outbreak of human brucellosis in Yantai City, Shandong Province.Methods:The information of a human brucellosis cluster outbreak case in Yantai City, Shandong Province in 2022 was collected, the strains were isolated and cultured, and DNA was extracted. BCSP31-PCR was used for species identification, and AMOS-PCR was used for species type identification. Multiple locus variable-number tandem-repeat analysis (MLVA)-16 was used for clustering analysis, and the results were compared with the public database MLVAbank and the monitoring data of Brucella in Shandong Province in 2022. At the same time, whole genome single nucleotide polymorphism (wgSNP) typing was used to analyze the 53 Brucella strains that had completed whole genome sequencing in Shandong Province in 2022, and the wgSNP phylogenetic tree was constructed. Results:According to BCSP31-PCR and AMOS-PCR identification, the three strains related to the cluster outbreak of brucellosis in Yantai City, Shandong Province in 2022 were all Brucella melitensis biotype. The results of MLVA-16 typing showed that the MLVA-16 typing of the three isolated strains was completely consistent, with 16 tandem repeat loci of 1-5-3-13-2-2-3-2-4-41-8-4-4-3-6-5, belonging to the Eastern Mediterranean clade. Compared with MLVAbank, the MLVA-16 typing of two strains isolated from Kazakhstan was consistent with the results of this study. Compared with the monitoring data of Brucella in Shandong Province in 2022, it was found that the MLVA-16 typing of 11 isolated strains was consistent with the results of this study, which were isolated from Zaozhuang, Linyi, Taian, Yantai, and Weifang cities, respectively. The results of wgSNP typing showed that the distance between the 11 strains and the strains of the current outbreak was less than 7 single nucleotide polymorphisms, and the strains were isolated from Taian, Zibo, Linyi, Binzhou, Jinan, Jining, Yantai and Weihai cities, respectively. Conclusion:After tracing the source of a human brucellosis cluster outbreak in Yantai City, Shandong Province in 2022, it is speculated that the strains of Brucella melitensis isolated from Linyi, Taian and Yantai cities are closely related, indicating that sheep in these areas have homology.

Objective:To investigate the drug resistance status and genomic characterization of Proteus mirabilis (PM) isolated from outpatient cases with diarrhea in Tai′an City and Laizhou City, Shandong Province. Methods:A total of 510 fecal samples were collected from 510 patients with acute diarrhea admitted to 43 sentinel hospitals in Tai′an City and Laizhou City, Shandong Province, between January 2021 and December 2022. The samples were cultured and isolated to identify Proteus spp. by direct inoculation, the drug susceptibility testing was performed by microbroth dilution method, and resistance genes and virulence genes were obtained by whole genome sequencing and bioinformatic analysis, thereby revealing the genetic environment surrounding the blaOXA-1 and blaCTX-M-65 genes. Single nucleotide polymorphism (SNP) analysis and core genome multilocus sequence typing (cgMLST) were conducted on the current strains and 100 PM isolates downloaded from the National Center for Biotechnology Information (NCBI) database via customizable methods utilizing RidomSeqSphere+ software, with the objective of exploring the phylogenetic relationships among the strains. Results:A total of 35 strains of Proteus were isolated from 510 fecal samples, including 31 strains of PM with a detection rate of 6.08% (31/510) and four strains of Proteus vulgaris.The multidrug resistance rate of PM was 100.00% (31/31).The 35 isolates carried a total of 43 resistance genotypes.Thirteen strains of PM carried blaOXA-1, six strains carried both blaOXA-1 and blaCTX-M-65, and 15 PM strains carried at least 15 antibiotic resistance genes (ARGs). The virulence genes included ureA, mrpA, ZapA, hpmA and so on. blaOXA-1 and blaCTX-M-65 genes were surrounded by mobile elements such as Tn3, ISL3 and IS6. cgMLST showed consistency with the SNP clustering results. Isolate 2022LZ41 from Laizhou City clustered with isolates 2022TA018, 2022TA017 and 2022TA019 from Tai′an City, with the number of allelic differences ranging from zero to two, and the Laizhou City isolate 2022LZ40 was highly genetically related to strain CRK0056 (human, USA, 2015). Conclusions:PM isolated from patients with diarrhea is multidrug-resistant, carrying many resistance and virulence genes.The presence of mobile genetic elements can lead to horizontal transfer of resistance genes.

Objective:To characterize and analyze the genetic variation of hemagglutinin (HA) of influenza A (H1N1) pdm09 subtype virus in Shandong Province, and explore the genetic variation patterns for providing reference for influenza monitoring, epidemic prevention and control, and vaccine strain selection.Methods:HA gene sequences of the recommended strains of influenza vaccine from 2009 to 2024 and the representative strains of each branch were downloaded from the GISAID Influenza Data Platform, and were phylogenetically analyzed and characterized in terms of amino acid site variation with the HA gene sequences of 298 influenza A (H1N1) virus strains isolated from Shandong Province. A phylogenetic tree was constructed using the maximum likelihood (ML) method of the IQ-TREE online tool, and the amino acid site variants were viewed using MegAlign software. The potential glycosylation sites of the HA gene were predicted using the NetNGlyc 1.0 online software.Results:The HA gene homology of the 298 influenza A (H1N1) viruses isolated in Shandong Province ranged from 91.2% to 100.0%. The evolutionary branches were gradually distantly related over time, but the direction of evolution was roughly the same as that in other provinces. Amino acid mutations in the HA occurred every year and most were found in the antigenic determinants.Conclusions:The HA genes of influenza viruses isolated in Shandong Province from 2009 to 2024 are still in the process of continuous evolution, and continuous monitoring of the epidemiological trends and the evolutionary directions of influenza viruses is essential for early warning of influenza virus pandemics.

Objective To investigate the molecular epidemiological characteristics of Proteus mirabilis from healthy populations, animals, and environmental sources in rural areas of Zhucheng, Weifang City, Shandong Province, China. Methods In this study, drug susceptibility testing was conducted on Proteus mirabilis isolated from healthy populations, animal feces, and sewage samples in Zhucheng, Weifang City, Shandong Province, China. The genetic environment surrounding the blaNDM-1 resistance gene was elucidated through whole-genome sequencing, and the genetic evolutionary relationships among strains were investigated through core genome multilocus sequence typing (cgMLST) and single nucleotide polymorphism (SNP) analysis. Results A total of 840 human fecal samples, 336 animal fecal samples, and 48 sewage samples were collected; the positivity rates were 3.21%, 0.89%, and 2.08%, respectively. Proteus mirabilis (PM) showed high sensitivity to meropenem (96.97%), ertapenem (96.97%), ceftazidime (84.85%), ceftazidime/avibactam (90.91%), and tigecycline (100%). A total of 54 antibiotic resistance genes were identified, with high detection rates of tet(J) (81.81%) and cat (81.81%). Two sewage-sourced PM strains carried both blaNDM-1 and blaOXA-1 resistance genes. The blaNDM-1 gene was flanked by IS91, ISVsa3, and IS6 insertion sequences. The sewage-derived isolates (E3DJ004, C3DJ004) and alleles such as 5pro, 16pro (2017, China, human) had only 69 SNP differences, indicating high genetic similarity. Strains (3BF020, 3BH05801) and (3BK028, 3BL044, 3BL045) were closely related (allelic and SNP differences <3), all of human origin, with SNP results consistent with cgMLST results. Conclusions Although PM in this study remains sensitive to carbapenems, it carries a greater number of drug-resistant genes. To prevent the undetected dissemination of drug-resistant genes, monitoring of multi-source samples from humans, animals, and the environment should be strengthened, to prevent the spread of drug-resistant bacteria at the "human-animal-environment" interface.

Objective:To analyze the cause and epidemiological characteristics of an outbreak of cutaneous anthrax in Caoxian County, Heze City, Shandong Province, and to provide scientific basis for anthrax prevention and control.Methods:Using on-site epidemiological investigation methods and the "Anthrax Epidemiological Case Investigation Form", case investigations were conducted based on the epidemiological contact history and close contacts of suspected anthrax cases reported by the national health care system ( n = 83). Scorched skin smears, diseased cattle tissues, soil samples from the slaughter site and smears from slaughter utensils were collected from cases for Real-time PCR testing and pathogenic bacteria isolation and culture, respectively. Anthrax determination criteria were carried out with reference to "Anthrax Diagnosis" (WS 283-2020). Results:A total of 13 cases of cutaneous anthrax were found in this outbreak, including 12 clinically diagnosed cases and one confirmed case (positive Real-time PCR test and isolation of a strain of Bacillus anthracis). The epidemiological investigation determined that the source of infection in this outbreak was diseased cattle, the transmission route was through slaughter of diseased cattle, contact with contaminated utensils and related cattle products, and the patients were mainly engaged in occupations related to cattle slaughter or cattle product collection and sale. A total of 84 samples were collected, including 13 skin scabs, 64 environmental samples and 7 beef samples. Thirty-six positive PCR tests were performed, with a positive rate of 42.86% (36/84). Among them, 100.00% (13/13) were positive for skin scab smear specimens, 29.69% (19/64) for environmental samples and 4/7 for beef samples. A total of 8 strains of Bacillus anthracis were isolated, including 6 environmental specimens, 1 suspected case and 1 beef strain, with an overall detection rate of 9.52% (8/84). Eighty-three close contacts were investigated. Thirteen households involved in the epidemic were disinfected by spraying (200 ml/m 2) with chlorine-containing disinfectant (5 000 mg/L), and a total of 40 households involved in the epidemic were disinfected, covering an area of about 10 765 m 2. Forty-five pieces of suspected contaminated clothing were burned and disposed of, and 152 pieces of kitchenware were soaked. Conclusions:Slaughter of infected cattle, contact with contaminated utensils and related cattle products are the main causes of this skin anthrax outbreak. Strengthening market supervision, deepening inter-animal epidemic prevention, carrying out publicity and education on anthrax prevention and control, and enhancing practitioners' awareness of disease prevention is the key to prevent anthrax from occurring.

Enterotoxigenic Escherichia coli（ETEC）infection can induce watery diarrhea，leading to dehydration，electrolyte disturbance，and even death in severe cases. Recombinant B subunit/inactivated whole-cell cholera（rBS/WC）vaccine is effective in preventing ETEC infectious diarrhea. On the basis of the latest evidence on etiology and epidemiology of ETEC，as well as the effectiveness，safety，and health economics of rBS/WC vaccine，National Clinical Research Center for Child Health（The Children’s Hospital，Zhejiang University School of Medicine）and Zhejiang Provincial Center for Disease Control and Prevention invited experts to develop expert consensus on rBS/WC vaccine in prevention of ETEC infectious diarrhea. It aims to provide the clinicians and vaccination professionals with guidelines on using rBS/WC vaccine to reduce the incidence of ETEC infectious diarrhea.

Objective:To study the infection of human rhinovirus, respiratory syncytial virus and human adenovirus in Jinan from April 2018 to March 2019, and analyze epidemiological characteristics of human adenovirus.Methods:All of 1969 nasopharyngeal swabs were collected from hospitalized patients with acute respiratory tract infections in The Fourth People’s Hospital of Jinan, Qilu Children′s Hospital of Shandong University, Peoples Hospital of Zhangqiu District from April 2018 to March 2019, fluorescence quantitative PCR was used to detect the positive rate of human rhinovirus, respiratory syncytial virus and human adenovirus. Seven adenovirus positive samples were isolated and examined by sequencing, then we determined adenovirus type, constructed gene phylogenetic trees for analysis.Results:Of the 1969 samples, 242 were positive, the total positive rate was 12.30% (242/1969), the positive rate was 3.00% (59/1969) for rhinovirus, 6.30% (124/1969) for respiratory syncytial virus (RSV), and 3.86% (76/1969) for adenovirus. There was no significant difference in the detective rate of rhinovirus in different age groups (Fisher′s exact test value =8.376, P=0.720), the positive rates of RSV and adenovirus in different age groups was statistically significant ( χ2=19.28, 12.16; P=0.001, 0.016). There was a statistically significant difference in the positive rate of adenovirus between different sexes ( χ2=14.33, P<0.001), and there was no statistically significant difference in the positive rate of rhinovirus and RSV between males and females ( χ2=0.30, 2.90, P=0.862, 0.089). Comparing the positive rates of viral nucleic acid in different months, we found that the positive rate of rhinovirus, RSV and adenovirus separately reached the highest in October, December and November (8.61%, 26.50% and 8.84%). We constructed a gene phylogenetic tree after seven positive samples of adenoviruses were sequenced, by the molecular typing method we detected that seven adenovirus-positive samples were all HAdV-2 type. Conclusions:By comparing the epidemiological trends of human rhinovirus, RSV and human adenovirus in Jinan from April 2018 to March 2019 in different ages, genders, and months, providing reference basis for the early prevention and clinical treatment of acute respiratory tract infection.