Objective To analyze the epidemic characteristics of brucellosis in Yilan County, Heilongjiang Province, and to provide theoretical reference and scientific basis for prevention and control of brucellosis. Methods Descriptive epidemiology methods were used to analyze the cases of brucellosis in Yilan County in 2012 - 2016. The epidemiological characteristics of brucellosis in Yilan County were analyzed in time distribution, regional distribution and population distribution. Results The total of reported brucellosis was 385, the average annual incidence rate was 18.33/100 thousand, among them, most cases occurred in 2013, which was 92 cases, the incidence rate was 21.90/100 thousand, and a total of 64 cases were diagnosed in 2014, with the lowest morbidity, the incidence rate was 15.24/100 thousand. The peak of incidence happened from February to July, the number of cases was 269, accounting for 69.87％. The number of cases in other months was 116 cases, which occupied 30.13％of the total cases. In 2012-2016, the disease was spreading to every township and village of Yilan. Yugong village had the highest morbidity, it was 43.50/100 thousand, and there were 87 villagers suffered from this disease in total. Yilan township had the lowest morbidity, it was 5.66/100 thousand, and there were 30 patients. Male had the highest incidence, male and female incidence ratio was 3.64:1.00 (302:83). The peak age of onset was 31-60 years old, accounting for 72.47％ (279/385). After analyzing the incidence of occupational groups, farmer was the highest, accounting for 90.13％ (347/385). Most of brucellosis patients contacted with pigs, cows and sheep, accounted for 56.36％ (217/385). Conclusions There are many cases of brucellosis in Yilan County, and the occupation is mainly farmers. The infection route is mostly in contact with livestock. In the future, in response to the epidemiological characteristics of brucellosis in Yilan County, appropriate preventive measures should be taken to control the local outbreak.

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 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.