19株多杀巴斯德菌感染的临床特征和病原学特点OA

Objective To analyze the clinical characteristics,antimicrobial susceptibility profiles,and molecular typing features of clinically isolated Pasteurella multocida(P.multocida),and provide basis for clinical diagnosis and treatment.Methods Clinical data and strains of 19 confirmed cases with P.multocida infection in three tertia-ry first-class hospitals in Hainan Province from December 2020 to December 2024 were retrospectively collected.The strains were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS)and kmt gene polymerase chain reaction(PCR),and a phylogenetic tree was constructed by full-length 16S rRNA gene sequencing.Capsule serotypes(A/B/D/E/F)and LPS genotypes(L1-L8)were detected by multi-plex PCR.Sequence typing analysis was performed based on the RIRDC-MLST typing system.The diameters of the inhibition zone of 8 antimicrobial agents were detected using Kirby-Bauer disc diffusion method,and the activity of β-lactamase activity was detected by nitrocefin test.Results 19 clinical strains were all identified as P.multoci-da,and 16S rRNA gene sequence analysis showed single nucleotide polymorphism differences among the strains.Based on RIRDC-MLST,13 strains(68.42％)were identified as 7 known sequence types(ST5,ST7,ST9,ST50,ST129,ST287,ST487),and 6 strains(31.58％)didn't match the existing database.The distribution of capsule serotypes showed that type A was dominant(13/19,68.42％),and the L3 genotype had the highest proportion among LPS genotypes(8/19,42.11％).Antimicrobial susceptibility testing results showed the highest susceptibility rate of 100％(n=19)for compound sulfamethoxazole and the susceptibility rate of 78.95％(n=15)for penicillin,ampicillin,and tetracycline.Ceftriaxone had a susceptibility rate of 89.47％(n=17).The resistance rate of eryth-romycin was 100％(n=19),and the susceptibility rate of azithromycin and levofloxacin were both 94.74％(n=18).The positive rate of β-lactamase was 21.05％(n=4).Conclusion The 19 clinical strains of P.multocida in this study showed a significant molecular diversity,and the sequence type ST7 and capsule type A may be the domi-nant types in this region.It is recommended to avoid empirical use of penicillin and ampicillin in clinical practice,and select susceptible antimicrobial agents based on antimicrobial susceptibility testing results.