ABSTRACT
Objective To collect the laboratory parameters and clinical parameters of blood culture positive samples,and analyze the composition and laboratory characteristics of real pathogens by combining with clinical follow-up and anti-infectious treatment outcomes.Methods We conducted a prospective study to isolate the 483 strains of pathogens from 4313 cases of blood samples for clinical examination between March 2013 and March 2015.The results of laboratory and clinical infections were collected for each positive culture and were followed up for clinical follow-up to understand the responsible doctors' experience-based judgment and targeted clinical treatment of antibiotics.After comprehensive analysis we determined the real pathogens and contaminants.Results Of the 483 positive cultures,331 were finally determined as pathogenic ones,accounting for 68.5% of the number of positive isolates; 97 were contaminated bacteria (20.1%); and 55 strains with uncertain pathogenic nature (11.4%).Escherichia coli accounted for the highest proportion (41.2%)of pathogenic bacteria.Coagulase-negative staphylococci took up the highest proportion (75.3%)of the contaminated bacteria.As many as 253 strains (52.4%)were detected from the aerobic or anaerobic bottles.The detection rate of Escherichia coli in anaerobic bottles (23.9%)was higher than that in aerobic bottles (13.8%)(P <0.05).Of 97 strains of positive isolates,only one bottle was reported positive for 90 strains,accounting for (92.8%),and more than two bottles of 7 positive strains,accounting for (7.2%)(P <0.05).34 positive in 24 h (35.1%),77 positive in 48 h (79.4%),the positivebacteria ratio within 48 h (79.4%)was higher than that of bacteria contamination ratio within 24 h (χ2 =38.935, P =0.000),with a significant difference.Conclusion Establishment of contaminated bacteria in blood culture cannot rely solely on laboratory or clinical parameters.It should be combined with the experience of clinicians to determine the clinical response to comprehensive judgments.For the laboratory to determine the presence of contamination,the number of positive bottles and the amount of sun are still two factors of important value.Paying attention to inspection of anaerobic bottles is more conducive to the detection of Escherichia coli.
ABSTRACT
Objective To confirm the species of multidrug-resistant Acinetobacter baumannii (MRAB)strains collected from our hospital by specific PCR amplification,and further investigate their distribution,antibiotic resistance and molecular classification characteristics.Methods We collected 47 MRAB clinical strains which had been identified by VITEK-2 system,followed by species confirmation using specific primers sp2F,sp4F and sp4R through PCR amplification.Antibiotic resistance characteristics were detected using VITEK-2 system.And the homology of MRAB isolates was analyzed using multilocus sequence typing (MLST).Results We confirmed 46 out of 47 strains as A .baumannii .All of them were multidrug-resistant strains,and the majority of them were found in sputum samples from patients in intensive care units (ICUs).MLST analysis found 4 ST types,namely ST195,ST218,ST368 and ST208.The last two types had the closest genetic relationship.Conclusion SpecificPCR amplification is a rapid and accurate method to identify A .baumannii .The MRAB strains in our hospital are mainly distributed in ICUs and are susceptible to only a few antibiotics such as tigecycline.
ABSTRACT
Objective To collect the laboratory parameters and clinical parameters of blood culture positive samples,and analyze the composition and laboratory characteristics of real pathogens by combining with clinical follow-up and anti-infectious treatment outcomes.Methods We conducted a prospective study to isolate the 483 strains of pathogens from 4313 cases of blood samples for clinical examination between March 2013 and March 2015.The results of laboratory and clinical infections were collected for each positive culture and were followed up for clinical follow-up to understand the responsible doctors' experience-based judgment and targeted clinical treatment of antibiotics.After comprehensive analysis we determined the real pathogens and contaminants.Results Of the 483 positive cultures,331 were finally determined as pathogenic ones,accounting for 68.5% of the number of positive isolates; 97 were contaminated bacteria (20.1%); and 55 strains with uncertain pathogenic nature (11.4%).Escherichia coli accounted for the highest proportion (41.2%)of pathogenic bacteria.Coagulase-negative staphylococci took up the highest proportion (75.3%)of the contaminated bacteria.As many as 253 strains (52.4%)were detected from the aerobic or anaerobic bottles.The detection rate of Escherichia coli in anaerobic bottles (23.9%)was higher than that in aerobic bottles (13.8%)(P <0.05).Of 97 strains of positive isolates,only one bottle was reported positive for 90 strains,accounting for (92.8%),and more than two bottles of 7 positive strains,accounting for (7.2%)(P <0.05).34 positive in 24 h (35.1%),77 positive in 48 h (79.4%),the positivebacteria ratio within 48 h (79.4%)was higher than that of bacteria contamination ratio within 24 h (χ2 =38.935, P =0.000),with a significant difference.Conclusion Establishment of contaminated bacteria in blood culture cannot rely solely on laboratory or clinical parameters.It should be combined with the experience of clinicians to determine the clinical response to comprehensive judgments.For the laboratory to determine the presence of contamination,the number of positive bottles and the amount of sun are still two factors of important value.Paying attention to inspection of anaerobic bottles is more conducive to the detection of Escherichia coli.
ABSTRACT
Objective To confirm the species of multidrug-resistant Acinetobacter baumannii (MRAB)strains collected from our hospital by specific PCR amplification,and further investigate their distribution,antibiotic resistance and molecular classification characteristics.Methods We collected 47 MRAB clinical strains which had been identified by VITEK-2 system,followed by species confirmation using specific primers sp2F,sp4F and sp4R through PCR amplification.Antibiotic resistance characteristics were detected using VITEK-2 system.And the homology of MRAB isolates was analyzed using multilocus sequence typing (MLST).Results We confirmed 46 out of 47 strains as A .baumannii .All of them were multidrug-resistant strains,and the majority of them were found in sputum samples from patients in intensive care units (ICUs).MLST analysis found 4 ST types,namely ST195,ST218,ST368 and ST208.The last two types had the closest genetic relationship.Conclusion SpecificPCR amplification is a rapid and accurate method to identify A .baumannii .The MRAB strains in our hospital are mainly distributed in ICUs and are susceptible to only a few antibiotics such as tigecycline.