Abstract:

Objective To analyze the characteristics of drug resistance，biofilm forming ability，virulence gene and drug resistance gene in Klebsiella pneumoniae （KP） from different clinical samples，and to provide a reference for controlling nosocomial infection. Methods Totally，148 KP isolates from sputum，midstream urine and blood samples were collected from 3 teaching hospitals in Xinxiang from November 2021 to September 2022. Bacterial identification and drug susceptibility test were performed by automatic microbial identification system. Polymerase chain reaction （PCR） was used to determine serotypes，virulence genes and drug resistance genes. Stringing test was used to determine high viscosity phenotype，and crystal violet staining was used to determine biofilm formation. Results Among 148 KP isolates，55（37.2%）isolates were isolated from sputum samples，40（27.0%）isolates were isolated from blood samples，and 53（35.8%）isolates were isolated from midstream urine samples. The isolation rate of strong biofilm forming isolates in midstream urine samples （54.3%） was higher than those in sputum samples（27.45%）and in blood samples（29.73%）（P=0.027），and the drug resistance rate （69.8%） was higher than that in sputum samples （49.1%）（P=0.028）. The highest carrying rate of drug resistance gene was blaSHV-1（85.8%）. The determination rates of KP virulence genes，iroN and rmpA，in sputum samples were higher than those in midstream urine samples （P=0.004） and blood samples （P=0.012）. The carrying rates of wabG，fimH and mrkD genes were >93.2%. KP carrying iroN，iucA，rmpA genes and K1 and K2 serotypes were sensitive to antibiotics and easily determined high viscosity phenotype （P<0.05）. The proportion of KP isolates with high viscosity phenotype was higher than that of KP isolates without high viscosity phenotype （P<0.001），and KP isolates with high viscosity were more sensitive to antibiotics （P<0.05）. The 74.5% of sputum samples had KP with 4 or more virulence genes，which was higher than those of blood samples （52.5%） and midstream urine samples （49.1%） （P=0.016）. The biofilm forming KP isolates carried more wabG ，mrkD，uge and fimH genes （P<0.05）. Conclusions he drug resistance rate of KP from midstream urine samples is high，which is easy to form strong biofilm. Some specific virulence genes are prevalent in KP. The composition of KP virulence genes from sputum samples is complex. The iroN and rmpA genes are associated with KP infection in respiratory system. The iroN，iucA，rmpA genes and K1，K2 serotypes are associated with high viscosity phenotypes，and KP isolates containing these genes and serotypes are more sensitive to antibiotics.

Key words: Klebsiella pneumoniae, Sputum, Midstream urine, Blood, High viscosity, Virulence gene, Biofilm, Drug resistance