Objective:To analyze the short-term hospital-based transmission characteristics and gene variation of Carbapenem-Resistant Klebsiella pneumoniae (CRKP) by genome-wide technique to provide evidence for transmission control. Methods:The experimental strain was derived from all the CRKP isolated in Affiliated Hospital of North China University of Science and Technology from October 2022 to December 2023. Strain identification and drug susceptibility were tested with VITEK 2-Compact automatic bacterial identification drug susceptibility analyzer or disk method, and the results were interpreted through whole genome sequencing. The ST type, carbapenem resistance gene, virulence factor, and O serotype of the collected strains were analyzed.Results:Among the 115 strains of CRKP, 94 strains were isolated from the intensive care unit (ICU), accounting for 81.7%, and 21 strains were isolated from the non-intensive care unit (NICU), accounting for 18.3%. The 115 strains of CRKP can be divided into 11 ST types, of which ST11 type was the most (54.8%, 63/115), followed by ST15 type (22.6%, 26/115) and ST5492 type (15.7%, 18/115). Type ST5492 was a new clonal group in the region. The 115 strains of CRKP could be divided into 7 O serotypes, most of which were O2a type(32.2%,37/115), followed by O5 type(30.4%,35/115) and O1 type(27.8%,32/115). The resistance genes of carbapenem antibiotics showed that there were 107 strains carrying the blaKPC-2 gene, one strain with the blaNDM-1 gene, and one strain with both the blaKPC-2 and blaNDM-13 genes. Virulence genes were detected in 55 CRKP strains (47.8%, 55/115), among which six strains detected peg-344, iucA, iroB, rmpA, and rmpA2 virulence genes (5.2%, 6/115). Four virulence genes ( peg-344, iucA, rmpA, and rmpA2) were detected in 34 strains (29.6%, 34/115). Three virulence genes ( iucA, iroB and rmpA) were detected in two strains (1.7%, 2/115). Three virulence genes ( peg-344, iucA and rmpA) were detected in one strain (0.8%, 1/115). IucA and rmpA virulence genes were detected in 12 strains (10.4%, 12/115). KPC-2_ST11_O2a, KPC-2_ST15_O1 and KPC-2_ST5492_O5 were dominant clones, and their distribution was mainly in the intensive care unit. The whole genome sequence analysis showed that there were three dominant clones, among which ST11 clones were subdivided into three dominant O serotypes, all of which were mainly in the intensive care unit. Conclusion:The popular strain in the hospital of CRKP is a KPC-2_ST11 clone group carrying iucA, rmpA/rmpA2, with cross-department transmission and mutation. ST5492 is a newly-launched clone type. The intensive care unit of hvKP carrying five virulence genes, including peg-344, should be alert to the epidemic risk of CR-hvKP outbreak.

Objective:To analyze the carriage status, subtype distribution and flanking gene sequence characteristics of oxacillinases (OXA enzyme) in 241 clinical strains of Pseudomonas aeruginosa, and assess their roles in the drug resistance of Pseudomonas aeruginosa and ability to horizontally transfer across species. Methods:Clinical P. aeruginosa isolates were collected from four hospitals in Sanya, Tangshan, Zhangjiakou, and Beijing. The prevalence of oxacillinases and their flanking gene sequences was analyzed by whole-genome sequencing (NGS) and bioinformatic approaches. Results:A total of 241 isolates of P. aeruginosa were gathered, and 35 blaOXA subtypes were identified through screening of 252 blaOXA genes. These genes were classified into three subfamilies: blaOXA-50-like (241, 95.6%), blaOXA-1-like (9, 3.6%) and blaOXA-10-like (2, 0.8%). Among these, 11 subtypes (11, 31.4%) were novel blaOXA subtypes. Nine of these belonged to the blaOXA-50-like subfamily and were designated as blaOXA-1244, blaOXA-1245, blaOXA-1246, blaOXA-1250, blaOXA-1252, blaOXA-1253, blaOXA-1254, blaOXA-1255, and blaOXA-1256. The remaining two belonged to the blaOXA-10-like subfamily and were named blaOXA-1247 and blaOXA-1248. Compared to the amino acid sequence of OXA-10, the newly identified subtype OXA-1247 exhibited a mutation at position 117, where a valine was replaced by a leucine. This change was thought to improve the enzyme′s ability to hydrolyze carbapenems. In the analysis of the flanking sequences of the blaOXA genes, Class I integrons were identified in four bacterial strains. The variable regions of these integrons carried three distinct patterns of resistance gene cassettes: aac( 6′) -Ib-blaOXA-1247-ant( 3′′) -Ia, aac( 6′) -Ib-blaOXA-1248 and aac( 6′) -Ib- blaIMP-45-blaOXA-1-catB3. Among these, the strain BJ2326 carried a class I integron that was connected to the downstream IS CR1 element to form a composite class I integron structure, additionally carrying the resistance gene blaPER-1. Out of the 223 non-wild-type P. aeruginosa strains, 127 strains exhibited non-wild-type profiles to the four beta-lactam antibiotics MEM, CAZ, FEP, and TZP, with the combination of MEM+CAZ+FEP being the most prevalent, representing 57.0% of the total. Conclusions:The blaOXA genes in 241 clinical P. aeruginosa strains showed diversity. Some blaOXA genes had a co-transfer risk with the metallo-β-lactamase resistance gene blaIMP-45. Among the 11 newly discovered blaOXA subtypes, the new subtype OXA-1247 may have carbapenemase activity and potential for horizontal transfer.

Objective:To analyze the short-term hospital-based transmission characteristics and gene variation of Carbapenem-Resistant Klebsiella pneumoniae (CRKP) by genome-wide technique to provide evidence for transmission control. Methods:The experimental strain was derived from all the CRKP isolated in Affiliated Hospital of North China University of Science and Technology from October 2022 to December 2023. Strain identification and drug susceptibility were tested with VITEK 2-Compact automatic bacterial identification drug susceptibility analyzer or disk method, and the results were interpreted through whole genome sequencing. The ST type, carbapenem resistance gene, virulence factor, and O serotype of the collected strains were analyzed.Results:Among the 115 strains of CRKP, 94 strains were isolated from the intensive care unit (ICU), accounting for 81.7%, and 21 strains were isolated from the non-intensive care unit (NICU), accounting for 18.3%. The 115 strains of CRKP can be divided into 11 ST types, of which ST11 type was the most (54.8%, 63/115), followed by ST15 type (22.6%, 26/115) and ST5492 type (15.7%, 18/115). Type ST5492 was a new clonal group in the region. The 115 strains of CRKP could be divided into 7 O serotypes, most of which were O2a type(32.2%,37/115), followed by O5 type(30.4%,35/115) and O1 type(27.8%,32/115). The resistance genes of carbapenem antibiotics showed that there were 107 strains carrying the blaKPC-2 gene, one strain with the blaNDM-1 gene, and one strain with both the blaKPC-2 and blaNDM-13 genes. Virulence genes were detected in 55 CRKP strains (47.8%, 55/115), among which six strains detected peg-344, iucA, iroB, rmpA, and rmpA2 virulence genes (5.2%, 6/115). Four virulence genes ( peg-344, iucA, rmpA, and rmpA2) were detected in 34 strains (29.6%, 34/115). Three virulence genes ( iucA, iroB and rmpA) were detected in two strains (1.7%, 2/115). Three virulence genes ( peg-344, iucA and rmpA) were detected in one strain (0.8%, 1/115). IucA and rmpA virulence genes were detected in 12 strains (10.4%, 12/115). KPC-2_ST11_O2a, KPC-2_ST15_O1 and KPC-2_ST5492_O5 were dominant clones, and their distribution was mainly in the intensive care unit. The whole genome sequence analysis showed that there were three dominant clones, among which ST11 clones were subdivided into three dominant O serotypes, all of which were mainly in the intensive care unit. Conclusion:The popular strain in the hospital of CRKP is a KPC-2_ST11 clone group carrying iucA, rmpA/rmpA2, with cross-department transmission and mutation. ST5492 is a newly-launched clone type. The intensive care unit of hvKP carrying five virulence genes, including peg-344, should be alert to the epidemic risk of CR-hvKP outbreak.

Objective:To analyze the carriage status, subtype distribution and flanking gene sequence characteristics of oxacillinases (OXA enzyme) in 241 clinical strains of Pseudomonas aeruginosa, and assess their roles in the drug resistance of Pseudomonas aeruginosa and ability to horizontally transfer across species. Methods:Clinical P. aeruginosa isolates were collected from four hospitals in Sanya, Tangshan, Zhangjiakou, and Beijing. The prevalence of oxacillinases and their flanking gene sequences was analyzed by whole-genome sequencing (NGS) and bioinformatic approaches. Results:A total of 241 isolates of P. aeruginosa were gathered, and 35 blaOXA subtypes were identified through screening of 252 blaOXA genes. These genes were classified into three subfamilies: blaOXA-50-like (241, 95.6%), blaOXA-1-like (9, 3.6%) and blaOXA-10-like (2, 0.8%). Among these, 11 subtypes (11, 31.4%) were novel blaOXA subtypes. Nine of these belonged to the blaOXA-50-like subfamily and were designated as blaOXA-1244, blaOXA-1245, blaOXA-1246, blaOXA-1250, blaOXA-1252, blaOXA-1253, blaOXA-1254, blaOXA-1255, and blaOXA-1256. The remaining two belonged to the blaOXA-10-like subfamily and were named blaOXA-1247 and blaOXA-1248. Compared to the amino acid sequence of OXA-10, the newly identified subtype OXA-1247 exhibited a mutation at position 117, where a valine was replaced by a leucine. This change was thought to improve the enzyme′s ability to hydrolyze carbapenems. In the analysis of the flanking sequences of the blaOXA genes, Class I integrons were identified in four bacterial strains. The variable regions of these integrons carried three distinct patterns of resistance gene cassettes: aac( 6′) -Ib-blaOXA-1247-ant( 3′′) -Ia, aac( 6′) -Ib-blaOXA-1248 and aac( 6′) -Ib- blaIMP-45-blaOXA-1-catB3. Among these, the strain BJ2326 carried a class I integron that was connected to the downstream IS CR1 element to form a composite class I integron structure, additionally carrying the resistance gene blaPER-1. Out of the 223 non-wild-type P. aeruginosa strains, 127 strains exhibited non-wild-type profiles to the four beta-lactam antibiotics MEM, CAZ, FEP, and TZP, with the combination of MEM+CAZ+FEP being the most prevalent, representing 57.0% of the total. Conclusions:The blaOXA genes in 241 clinical P. aeruginosa strains showed diversity. Some blaOXA genes had a co-transfer risk with the metallo-β-lactamase resistance gene blaIMP-45. Among the 11 newly discovered blaOXA subtypes, the new subtype OXA-1247 may have carbapenemase activity and potential for horizontal transfer.

Objective:To analyze the drug resistance characteristics of Klebsiella pneumoniae in the nasopharynx of hospitalized patients in North China from 2022 to 2023. Methods:From November 2022 to July 2023, nasopharyngeal swabs were collected from 100 inpatients in Affiliated Hospital of North China University of Science and Technology, and Klebsiella pneumoniae was isolated and cultured. At the same time, the clinical data of the patients were collected, including gender, age, department, clinical diagnosis of disease type, etc. The minimum inhibitory concentration of strains was detected by an automatic bacterial drug sensitivity system. The drug resistance genes, ST types, capsule serotypes and population structure of the strains were analyzed by whole genome sequencing and data analysis. Results:Klebsiella pneumoniae was isolated from 55 nasopharyngeal swabs of 100 inpatients(55.00%). Among the 55 inpatients with Klebsiella pneumoniae in the nasopharynx, 70.91% (39/55) were male, with an age distribution concentrated between 61 and 80 years old (58.18%, 32/55), and 50.91% (28/55) were in intensive care units (ICU). The main underlying disease type was nervous system disease (49.09%, 27/55). The results of drug sensitivity showed that the non-susceptibility rates of 55 strains of Klebsiella pneumoniae to cephalosporins, quinolones, aztreonam and nitrofurantoin were all more than 80.00%. Twenty-eight carbapenem-resistant Klebsiella pneumoniae strains (50.91%), 47 extended-spectrum β-lactamase producing strains (85.45%), and 48 multi-drug-resistant strains (87.27%) were detected. A total of 11 antibiotic resistance genes were detected, including carbapenems (carrying rate 76.36%) and extended-spectrum β-lactamase (carrying rate 96.36%). The 55 strains could be divided into 17 ST types, and the most common type was ST11 (25.45%). The 55 strains were divided into 18 capsular serotypes, among which K102 was the most prevalent (23.64%). OXA-1_ST307_K102 (21.82%) and KPC-2_ST5492_K125 (18.18%) were the dominant clones, distributed in the Department of Neurosurgery and ICU. The result of whole genome sequence analysis showed that there were four clusters with high homology among the 55 strains. The strains from the ICU formed two independent clusters, and strains from the Neurology ICU and Neurosurgery department formed one cluster respectively. Conclusion:The carrying rate of Klebsiella pneumoniae in the nasopharynx of inpatients is high, and the drug resistance of the strains is serious. There are many types of drug-resistant genes.

To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and r df_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, l mb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.

Objective:To analyze the drug resistance characteristics of Klebsiella pneumoniae in the nasopharynx of hospitalized patients in North China from 2022 to 2023. Methods:From November 2022 to July 2023, nasopharyngeal swabs were collected from 100 inpatients in Affiliated Hospital of North China University of Science and Technology, and Klebsiella pneumoniae was isolated and cultured. At the same time, the clinical data of the patients were collected, including gender, age, department, clinical diagnosis of disease type, etc. The minimum inhibitory concentration of strains was detected by an automatic bacterial drug sensitivity system. The drug resistance genes, ST types, capsule serotypes and population structure of the strains were analyzed by whole genome sequencing and data analysis. Results:Klebsiella pneumoniae was isolated from 55 nasopharyngeal swabs of 100 inpatients(55.00%). Among the 55 inpatients with Klebsiella pneumoniae in the nasopharynx, 70.91% (39/55) were male, with an age distribution concentrated between 61 and 80 years old (58.18%, 32/55), and 50.91% (28/55) were in intensive care units (ICU). The main underlying disease type was nervous system disease (49.09%, 27/55). The results of drug sensitivity showed that the non-susceptibility rates of 55 strains of Klebsiella pneumoniae to cephalosporins, quinolones, aztreonam and nitrofurantoin were all more than 80.00%. Twenty-eight carbapenem-resistant Klebsiella pneumoniae strains (50.91%), 47 extended-spectrum β-lactamase producing strains (85.45%), and 48 multi-drug-resistant strains (87.27%) were detected. A total of 11 antibiotic resistance genes were detected, including carbapenems (carrying rate 76.36%) and extended-spectrum β-lactamase (carrying rate 96.36%). The 55 strains could be divided into 17 ST types, and the most common type was ST11 (25.45%). The 55 strains were divided into 18 capsular serotypes, among which K102 was the most prevalent (23.64%). OXA-1_ST307_K102 (21.82%) and KPC-2_ST5492_K125 (18.18%) were the dominant clones, distributed in the Department of Neurosurgery and ICU. The result of whole genome sequence analysis showed that there were four clusters with high homology among the 55 strains. The strains from the ICU formed two independent clusters, and strains from the Neurology ICU and Neurosurgery department formed one cluster respectively. Conclusion:The carrying rate of Klebsiella pneumoniae in the nasopharynx of inpatients is high, and the drug resistance of the strains is serious. There are many types of drug-resistant genes.

To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and r df_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, l mb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.

Objective:To explore the feasibility of U6 and Cel-miR-39 as reference genes for quantitative detection of microRNA (miRNA) in cerebrospinal fluid (CSF) of tuberculous meningitis (TBM), and validate the difference of miRNAs between tuberculous and viral meningitis (VM).Methods:The remaining CSF specimens after routine examination were collected in Beijing Chest Hospital of Capital Medical University. A total of 36 TBM and 34 VM patients were enrolled based on the information in the medical records. Total RNA were extracted from the CSF samples, and Taqman based real-time quantitative PCR (RT-CR) analysis were performed to determine the concentration of the miRNAs in CSF. GeNorm, NormFinder and Bestkeeper software were used for stability analysis of the two reference genes. 2 -ΔCt method was used to determine the relative gene expression. Accordance of repeated tests was analyzed by Pearson correlation test. Continuous variables were compared by the t-test. Results:Among the 70 samples, the average cycle threshold (Ct) value of U6 was 30.40±3.30, while the average Ct value of Cel-miR-39 was 21.49±0.70. The expression level of Cel-miR-39 was higher than that of U6. Correlation analysis showed good accordance of the repeated tests among the reference genes and target genes analysis in the randomly selected 10 samples ( r>0.931, P<0.001). Based on the analyses results of the three software, including GeNorm, NormFinder and Bestkeeper, Cel-miR-39 presented better stability in RT-PCR analysis and was more suitable as a reference gene for miRNA quantitative determination in CSF sample of TBM patients. The relative expression levels of the three target miRNAs were calculated using Cel-miR-39 as the reference gene, and miR-126-3p (1.13±0.41 vs 3.34±0.82, t=2.452, P=0.016), miR-130a-3p (0.56±0.10 vs 2.59±0.70, t=2.960, P=0.004) and miR-151a-3p (0.64±0.25 vs 2.11±0.33, t=3.536, P<0.001) were showed significant lower expression levels in CSF in TBM group than that in VM group. Conclusions:Cel-miR-39 can be used as a reference gene for quantitative detection of miRNAs in CSF of TBM patients. Significant differences were detected in expression level of miR-126-3p, miR-130a-3p and miR-151a-3p between TBM and VM group.

Objective To describe a case of lower limbs infection of Helcococcus Kunzii in North China University of Science and Technology Affiliated Hospital in October 2017 and to analyze the etiology and drug susceptibility??Methods The bacteria were identified by French Meriere mass spectrometer and BD Phoenix?100 automatic bacterial identification／drug sensitivity system??The drug resistance of the bacteria was detected by disk diffusion method,and collected the clinical information and related literature information of the Helcococcus Kunzi to analyze??Results The Gram?positive cocci was isolated from the foot secretion of a patient with venous thrombosis of lower limbs complicated with infection??The result of smear was Gram?positive cocci in double,agglomerate and varied in size??On the blood plate,there was a small colony of α hemolysis??Thixozyme negative,β galactosidase negative??The results of mass spectrometry identification and two kinds of fully automatic bacterial identification ／ drug sensitivity system were identified as Helcococcus Kunzii,the isolates was resistant to erythromycin and clindamycin among the 10 antibiotics tested??By searching,sorting out and analyzing the literature information, it is revealed that the infection of this bacterium is not related to sex??Middle?aged and elderly people are mostly infected??And the cocci easily infected patients with lower immunity??The infection of lower limbs is 47??37%,the infection of blood flow is 15??79% and the other ways of infection are 42??11%( lung, mammary gland, etc??)??Conclusion Helcococcus Kunzii is a conditional pathogen, and patients with lower immunity are more common??Erythromycin resistance could identify it from the green balloon bacteria??Moreover, the bacteria could cause a wide spectrum of diseases,and easily cause sepsis and lower limbs infections,which reminds us that we should be vigilant in clinical practice??