Analysis Of Distribution And Drug Resistance Of Pathogenic Bacteria Of Urinary Tract Infection And Application Of PCR-quantum Dot Fluorescence Technique In Identification Of Pathogenic Bacteria Of Urinary Tract Infection

Objective:1.In order to screen out common pathogenic bacteria of urinary tract infection and provide basis for rational application of antibiotics for urinary tract infection in this area,the distribution and drug resistance of 4086 strains of pathogenic bacteria in urine culture were retrospectively analyzed.2.In order to provide a rapid and accurate detection method for clinical identification of pathogenic bacteria of urinary tract infection,19 common pathogenic bacteria were detected by PCR-quantum dot fluorescence method,and compared with the detection methods such as urine culture and Sanger sequencing.Methods:1.The urine culture positive results of 4086 patients in North Jiangsu People’s Hospital from January 2019 to December 2019 were statistically analyzed by WHONET version 5.6,and the data were statistically analyzed by SPSS 22.0 statistical software.2.Clean midcourse urine specimens from patients undergoing urine bacterial culture in North Jiangsu People’s Hospital from August 2020 to December 2020 were collected,and 465 patients with clean midcourse urine samples were screened according to the corresponding inclusion and exclusion schemes.The urine samples of 465 cases were detected by PCR-quantum dots fluorescence method and urine bacterial culture respectively(the positive results of urine culture were identified by identification card and identified by mass spectrometry),and the consistency of the results of PCR-quantum dots fluorescence method and urine culture was compared.Sanger sequencing was used for identification when PCR-quantum dots luorescence method were not consistent with the urine culture results.Results:1.Of the 4086 strains of pathogenic bacteria of urinary tract infection,mainly G~-bacteria,a total of 2835 strains(69.4%)were detected.The G~-bacteria with high detection rate were Escherichia coli,Klebsiella pneumoniae,Pseudomonas aeruginosa,Acinetobacter baumannii,Proteus mirabilis,Enterobacter cloacae and Citrobacter freundii,and the composition ratios were 52.6%,16.0%,8.4%,5.6%,3.9%,2.3%,and1.3%,respectively.826 strains of G~+bacteria(20.2%)were detected,mainly Enterococcus faecium and Enterococcus faecalis,with composition ratios of 40.6%and26.4%,respectively,followed by Staphylococcus epidermidis 9.8%,Streptococcus agalactiae 8.0%and Staphylococcus aureus 4.6%.425 strains(10.4%)of fungi were detected,and Candida albicans was the main strain with the composition ratio of70.6%.2.There were significant differences in the detection rates of G~-bacteria,G~+bacteria and fungi among different types of medical treatment(χ2=83.975,P<0.001),ages(χ2=21.558,P=0.001),genders(χ2=126.437,P<0.001)and departments(χ2=12.687,P=0.013).3.Drug resistance analysis showed that the resistance rates of Escherichia coli to amikacin,carbapenems,polymyxin were 1.6%,1.1-1.4%,1.3%,respectively.The resistance rates of Escherichia coli to cephalosporins(except cefotetan)and quinolones were over 53.0%and 60.0%,respectively.The drug resistance rates of Klebsiella pneumoniae to amikacin,polymyxin and tigacycline were all lower than 10.0%.Neither Enterococcus faecium nor Enterococcus faecalis were detected to be resistant to linezolid or tegacycline,and the drug resistance rates to vancomycin production were lower than 1.0%,and the drug resistance rates to teicolanin were lower than 10.0%.4.The PCR quantum dot fluorescence method was used to detect 465 urine specimens.Except for Streptococcus pyogenes which was not detected,the remaining18 pathogens(including Escherichia coli,Klebsiella pneumoniae,Pseudomonas aeruginosa,Acinetobacter baumannii,Proteus mirabilis,Citrobacter freundii,Enterobacter cloacae,Enterococcus faecium,Enterococcus faecalis,Staphylococcus epidermidis,Streptococcus agalactiae,Staphylococcus aureus,Staphylococcus saprophyticus,Candida albicans,Ureaplasma urealyticum,Chlamydia trachomatis,Neisseria gonorrhoeae,Mycoplasma genitalium)were all detected.5.Of the 465 urine samples tested by urine culture or PCR quantum dot method,404 samples were positive and 61 samples were negative.The results of urine culture and PCR quantum dot method were both positive in403 cases,and the positive coincidence rate of PCR quantum dot method and urine culture was 100.0%.One case of Ureaplasma urealyticum infection was reported by PCR quantum dot fluorescence method,while the urine culture report was negative.Sixty-one cases were negative for both methods,and the negative coincidence rate of PCR quantum dot method and urine culture was 98.4%.6.Among 404 positive results,304 cases reported monobacterial infection in culture and PCR.One case was found to be monobacterial infection by PCR quantum dot fluorescence,but the results of urine culture were negative.99 cases were reported to have polybacterial infection.Polybacterial infection:Polybacterial infection was reported in all 3specimens by PCR and culture.The 96 samples were reported as polybacterial infection by PCR quantum dot fluorescence method,while the urine culture was reported as monobacterial infection.7.Among the 96 samples reported as polybacterial infection by PCR quantum dots fluorescence method and those reported as monobacterial infection by urine culture,27 samples showed polybacterial infection of non-sexually transmitted disease(STD)pathogens,and 2 samples showed polybacterial infection of non-STD pathogens combined with STD pathogens.The DNA extracts of these 29 samples were sequenced by Sanger,and the results were consistent with those of PCR quantum dot fluorescence method.Sixty-seven cases were infections caused by single bacteria of non-STD pathogens combined with STD pathogens.8.All 465 samples were detected by PCR quantum dot fluorescence method,Ureaplasma urealyticum,Chlamydia trachomatis,Mycoplasma genitalium or Neisseria gonorrhoeae were detected in 70 samples(including69 samples with polybacterial infection and 1 sample with monobacterial infection).The results of PCR quantum dot fluorescence were consistent with those of Sanger sequencing.Conclusion:1.The main pathogenic bacteria of urinary tract infection are gram-negative bacteria,mainly Escherichia coli.The resistance rate of Escherichia coli to cephalosporin and quinolone antibiotics is high,so the routine use of these antibiotics is not recommended before the report of drug sensitivity results.2.There were differences in the distribution of pathogens among different genders,types of visits,ages and departments.Therefore,empiric drug treatment should be more targeted.3.PCR quantum dots fluorescence method has a faster identification speed than urine culture,and can be used to identify Ureaplasma urealyticum,Chlamydia trachomatis,Mycoplasma genitalium and Neisseria gonorrhoeae in urine samples.4.PCR quantum dot fluorescence method may be better than urine culture to detect polybacterial infection,and the identification of polybacterial infection pathogen has a higher accuracy.