| Background/Aims:Pseudomonas aeruginosa is a Gram-negative bacillus which extensive distribution.The microbe is one of the most common pathogen in opportunistic and hospital acquired infections.The aim of this study is to understand the isolating rates and infectious conditions of P.aeruginosa in the samples from different types of infectious diseases and resistance rates against different antibacterial drugs that will provide a basis for more efficient diagnosis and treatment of P.aeruginosa-infected diseases in clinic.Methods:1.The sputum,incision secretion,urine,ascites,bile and blood samples of emergency or hospitalized patients with infectious diseases in the Sir Run Run Shaw Hospital of Zhejiang University School of Medicine were collected during January to December in 2017.2.Streaking inoculation was performed to isolate and obtain bacterial colonies from the different clinical samples and then a single colony was inoculated for routine enrichment cultivation.3.VITEK-2 Compact Automatic Bacterial Analyzer plus GN bacterial identification card and MALDI-TOF mass spectrometry were used for identification of different bacterial isolates.4.The isolates of P.aeruginosa were identified again by EX-Taq high fidelity PCR using P.aeruginosa 16S rRNA gene-specific primers.5.The susceptibility of P.aeruginosa isolates to 17 antimicrobial drugs were determined by using VITEK-2 Compact Automatic Bacterial Analyzer plus AST-GN drug-sensitivity identification card and K-B slip diffusion method.6.The multi-drug resistance model analysis criteria were designed according to the American Clinical and Laboratory Standards Institute(CLSI),the European Committee On Antimicrobial Susceptibility Testing(EUCAST)and the US Food and Drug Administration(FDA)documents and judgment points.7.Using SPSS20.0 as a tool,the chi-square test and multivariate correspondence analysis of the statistical model were used to analyze the resistance rate of the above-mentioned P.aeruginosa clinical strains to different antibiotics and the multi-drug resistance model.Results:1.A total of 199 P.aeruginosa isolates were obtained from the samples of 859 cases with infectious diseases.All the isolates presented the expected size 16S rRNA gene fragments(1425 bp)after PCR amplification.2.Among the 199 cases with P.aeruginosa infection,lower respiratory tract infection such as pneumonia was the most common(35.7%,71/199)(χ2=24.8,p<0.05),followed by skin infection(14.1%,28/199),abdominal infection(13.1%,26/199),urinary tract infection(13.1%,26/199),upper respiratory tract infection(10.0%,20/199)and biliary tract infection(7.5%,15/199)(x 2=4.0,p<0.05).However,ear,blood and other infections were only accounted for 7.5%of the cases.3.In the 199 P.aeruginosa-infected patients,62.8%(125/199)were male and 37.2%(74/199)were female.The age range of patients ranged from 22 to 97 years old,in which 69.3%(138/199)of the patients were over 60 years old(χ 2=59.5,p<0.05)while 21.1%(42/199)or 9.6%(19/199)of the patients were 41-59 or 20-40 years old.4.In the 199 P.aeruginosa-infected patients,27%(54/199)and 26%(51/199)were from intensive care unit and general surgery,respectively,which was significantly more than that from other departments(χ2=17.7,p<0.05).5.The drug susceptibility tests showed that the sensitive rates of P.aeruginosa isolates against tobramycin and amikacin were 95.48%and 93.47%respectively,followed by gentamicin(88.44%),levofloxacin(72.36%)and piperacillin(70.51%),but the resistance rates were higher against tcompound neotamine,cefazolin,ampicillin,ampicillin/sulbactam,minocycline and ceftriaxone with 99.50%,98.99%,98.48%,97.99%,97.80%and 95.48%,respectively.6.55.3%(110/199)of the P.aeruginosa isolates were multi-drug resistant.The predominant multi-drug resistant patterns were listed as below:30.9%(34/110)were resistant to penicillin+cephalosporin+carbapenems and 39.1%(43/110)were resistant to penicillin+cephalosporin+carbapenem+quUnolones(χ2=25.1,p<0.05).7.There were significantly higher corelations between penicillin+cephalosporin+carbapenems resistance pattern and>60 years old males with lower respiratory infection,biliary tract infection or skin infection,male,penicillin+cephalosporin+carbapenem+quinolones resistance pattern and 41-59 or ≥60 years old males with abdominal infection,penicillin+cephalosporin+carbapenem+quinolone+aminoglycosides resistance pattern and>60 years old females with upper respiratory tract infection,and penicillin+cephalosporins+quinolones resistance pattern and 41-59 years old males with blood infection or urinary tract infection.Conclusions:Pneumonia is the main disease caused by P.aeruginosa infection.The population over 60 years old is susceptible to be infected with P.aeruginosa.Most of the P.aeruginosa-infected patients were from intensive care unit and general surgery.The P.aeruginosa isolates in this study were resistant to the commonly-used penicillin and cephem antibiotics and presented higher multi-drug resistant rates that indicate the necessity to isolate the strains of P.aeruginosa-infected patients for drug susceptibility test. |
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