2011-2012Hospital In Our City Patients Sputum Culture Analysis Of Distribution And Drug Resistance Of Pathogenic Bacteria

ObjectiveBased on a systematic retrospective analysis of the results in drug susceptibility testand bacterial culture of sputum specimens in pediatric in three top hospitals in our cityfrom2011-2012, we contrast the results of bacteria strains and resistance in the twoyears,understand the bacteria types,distributions,different strains of drug-resistantcharacteristics and resistance trends of children with respiratory tract bacterial infection.This study is helpful to drug use for pediatrician and public. On the result, the region’spediatriations can make rational use of antibiotics to reduce the incidence of bacterialresistant strains and develop experienced treatment programs, which can lead to a mostreasonable social and economic benefits ratio.Methods1. Case selection：select children aged0~14years old to meet the conditions based onthe results of drug susceptibility test and bacterial culture of sputum specimens frommicrobiological laboratory in the city’s top three hospitals. All children were divided intotwo groups: group A(2011.01.01~2011.12.31), group B (2012.01.01~2012.12.31).2.Statistical Analysis:: calculate the composition ratio of various pathogens andantimicrobial drug resistance rates (the same patients repeated strains would not beaccumulated) between the two groups by the chi-square test, P<0.05or0.01, the differenceis statistically significant, P>0.1the difference is not statistically significant. Use theWHOnet5.6statistical software to calculate resistance rate and infection rate, establish andanalyze drug susceptibility testing database. The chi-square test forthe rate was made bySPSS13.0statistical software.Results1. Rate of positive results for sputum culture Rate of positive results for sputum culture was lower. It took up to26.40%in2011while27.51%in2012. The chi-square test for the rates between two groups was notstatistically significant (P>0.1).2.Results of bacteria distribution2.1Bacteria distribution PercentageThe study showed that the major pathogens of children with respiratory tract infectionin the past two years was Gram-negative bacteria (77.6%in2011,69.1%in2012),whileGram-positive bacteria infection accounted for20.1%in2011and20.5%in2012. The twogroups showed no significant difference. But compared with other pathogens includingfungi (2.3%in2011,10.4%in2012), there existed a significant upward trend withstatistical significance. According to the percentages,Gram-negative bacteria rankings inthe two years were as follows:The top six Gram-negative bacteria in2011were Klebsiella pneumonia (28.5%),Escherichia coli (12.5%),Pseudomonas aeruginosa (10.6%) and Acinetobacter Bowman(18.2%), Pseudomonas maltophilia (3.5%),Enterobacter cloacae (3.2%). The top sixGram-negative bacteria in2012were Klebsiella pneumonia (34.1%), Escherichia coli(13.0%), Pseudomonas aeruginosa (26.1%), Acinetobacter Bowman(12.4%), Pseudomonasmaltophilia (3.6%), Enterobacter cloacae (3.5%).It indicated that Klebsiella pneumoniaeplayed a dominant role in children with respiratory tract infections, but the detectedquantity ofAcinetobacter Bowman decreased in2012compared to the one in2011, whilethe detected quantity of Pseudomonas aeruginosa showed a clear upward trend (P<0.05).Rankings of Gram-positive bacteria were successively Staphylococcus aureus,Streptococcus pneumoniae and Staphylococcus hemolytic. The distribution in the past twoyears ranked the same,but still Staphylococcus aureus was dominant in Gram-positivebacteria distribution.Therefore,Clinicians in the early empiric medication should take these types ofbacteria as the main suspect,and make rational drug selection based on the detected statusof microbiology effect and drug resistance.2.2Phenotypic resistance detection rateThe MRSA (+) strain detection rate of Staphylococcus aureus are24.3%in2011and37.9%in2012. ESBL (+) strains detection rate is15.4%in2011and17.9%in2012. InKlebsiella pneumoniae, ESBLs (+) strain detection rate is15.7%in2011and23.2%in2012. All results above showed a rising trend.3. Bacterial resistance analysis On the whole, compared overall situation in2012with that in2011,bacterialresistance rate showed an upward trend. According to the classification of bacteria, here weshowed analysis results as follows:3.1Klebsiella pneumoniae’s resistanceKlebsiella pneumoniae were highly resistant to penicillin antibiotics such asampicillin, ampicillinsulbactam,piperacillin, amoxicillin Rowe potassium andcephalosporins generation Ⅰsuch ascefazolin, with a percentage up to85%.Besides,resistance rate of ampicillin and cefazolin was more than95%, but highly sensitive topiperacillinsulbactam with92.8%.No significant difference showed in the comparison ofthe two years.The bacterial resistance rates were slightly lower to cephalosporinsgeneration Ⅲ and Ⅳ, such as cefepime, cefotaxime, ceftazidime, but the two-yearresistance comparison result showed an upward trend. To aminoglycosideamikacin,resistance rate was less than10%,and no difference showed in the comparison ofthe two years.To gentamicin,resistance rates in2012increased significantly. To quinolonessuch as ciprofloxacin, levofloxacin,resistance rate was loweredby about10%in2011, butin2012was increased by more than50%, thereforethis type of drugs should be carefullychosed. Klebsiella pneumoniae was still highly sensitive to imipenem, meropenem, forresistant strains had not been found yet. The study also found that the vast majority ofESBLs (+) strains’ resistance rate was significantly higher than ESBLs (-) strains (p<0.01).3.2Escherichia coli’s resistanceBoth drug resistance spectrum of Escherichia coli and Klebsiella pneumoniaewerealmost the same, but the former resistance rates were higher. Escherichia coli washighly resistant to penicillin antibiotics such as ampicillin, piperacillin, amoxicillin Rowepotassium and cephalosporins generation Ⅰsuch ascefazolin, with a percentage up to90%,butwas highly sensitive to piperacillinsulbactam and ampicillin sulbactam, with apercentage of more than90%.No significant difference showed in the comparison of thetwo years.The bacterial resistance rates were slightly lower to cephalosporins generationⅢand Ⅳ, such as cefepime, cefotaxime, ceftazidime, but the two-year resistance comparisonresult showed an upward trend and a significantly difference. To aminoglycosideamikacin,resistance rate was less than15%,and no difference showed in the comparison ofthe two years.To gentamicin,resistance rates in2012increased significantly. To quinolonessuch as ciprofloxacin,levofloxacin,resistance rate washigher about60%in2011,and tolevofloxacin,resistance rate is obviously higher up to80%. There was a upward trend and significant difference between the two years’ rate.To imipenem and meropenem,resistantstrains had not been foundwithin two years, but both produced ESBLs (+)strainswith ahigher resistance rate.3.3Pseudomonas aeruginosa’s resistancePseudomonas aeruginosa were highly resistant to penicillin antibiotics such asampicillin, ampicillin sulbactam,piperacillin, amoxicillin Rowe potassium andcephalosporins generation Ⅰsuch ascefazolin, with a percentage more than99%, while toampicillin and cefazolin,resistance rate was completely100%.However,it was highlysensitive to piperacillinsulbactam with92.8%.No significant difference showed in thecomparison of the two years.The bacterialresistance rates were slightly lower tocephalosporins generation Ⅲ and Ⅳ, such as cefepime, cefotaxime, ceftazidime, butthetwo-yearsresistance comparison result showed anupward trend. To aminoglycosideamikacin,resistance rate was less than10%,while with a rate of less than15%togentamicin, and no difference showed in the comparison of the two years.To quinolonessuch as ciprofloxacin, levofloxacin,resistance rate waslowered about20%,which showedno significant difference. To imipenem and meropenem,resistance rate was about20%.3.4Enterobacter cloacae’s resistanceEnterobacter cloacae were highly resistant to ampicillin,ampicillin-sulbactam, amoxicillin Rowe potassium and cefazolin.Besides, resistance rate of ampicillin,ampicillin-sulbactam and cefazolin was completely100%in2012.To cefepime, cefotaxime,ceftazidime, amikacin, gentamicin, ciprofloxacin, levofloxacin, aztreonam, the sensitiverate was above60%. To Imipenem, meropenem,resistant strains had not been found. Allresults showed no siginificant difference.3.5Acinetobacter Bowman’s resistanceAcinetobacter Bowman were highly resistant to penicillin antibiotics such asampicillin, ampicillin sulbactam,piperacillin, amoxicillin Rowe potassium and cephalosporins generationⅠ such ascefazolin, with a percentage up to100%.But to Piperacillinsulbactam and ampicillin sulbactam,resistance rate was about70%.No significant difference showed in the comparison of the two years.The bacterial resistance rates were slightlylower to cephalosporins generation Ⅲ and Ⅳ,such as cefepime, cefotaxime, ceftazidime,about70%, and the two-year resistance comparison result showed no upward trend. Toaminoglycoside amikacin and gentamicin, resistance rate was about60%,and no statisticalsignificance showed in the comparison of the two years.To quinolones such as ciprofloxacin, levofloxacin,resistance rate washigh of about10%, which showed no changes in the comparison. To Imipenem, meropenem, resistance rate was up to70%,and two-year comparesonshowed a rising trend.3.6Staphylococcus aureus’s resistanceStaphylococcus aureus were highly resistant to penicillin antibiotics such asampicillin, ampicillin-sulbactam,piperacillin, amoxicillin Rowe potassium andcephalosporins generation Ⅰsuch ascefazolin, with a percentage up to100%.To QuinolineNu PutinG-dalfopristin, nitrofurantoin morpholine Hubei ketone and teicoplanin, thebacteria performed a higher sensitive rate, while was highly resistant to tobramycin,gentamicin, amikacin, erythromycin. There was no emergence of vancomycin-resistantstrains. Two-year comparison showed no statistical significance.ConclutionsIn this study, among children with respiratory tract infections of0~14years old in thecity’s three top three hospitals, bacterial infections were caused mainly by Gram-negativebacteria, including Klebsiella pneumoniae,which was the most common pathogen, whilethe infections were dominated by Staphylococcusaureusin Gram-positive bacteria.Comparison between the past two years showed no significant changes in antimicrobial spectrum.A variety of bacteria were highly resistant to penicillins,cephalosporins generationⅠ andⅡ, but were highly sensitive to cephalosporins generation Ⅲ and Ⅳ, and the two-yearscomparison indicated a rising trend. To amikacin and gentamicin, the study showed ahigher sensitive rate, but both of the drugs should be carefully chosed, forthey can causenephrotoxicity and ototoxicity side effects. To ciprofloxacin and levofloxacin,resistancerates had risen, and such drugs should be applied to children with caution, therefore wemust be cautious with selection of such drugs.All pathogens remained highly sensitive tocarbapenems,however, as the last trump drug, carbapenems were not recommended to usein the case that other drugs can beselected,so as to minimize the screened possibility ofdruG-resistant strains.Not a last resort,it was the same as vancomycin should not be used inthe treatment of staphylococcal.