| Objection: To discuss the drug-resistant conditions of Acinetobacterwhich detect in lower respiratory tract and the relationship between the outmembrane protein and pathogenicity in the different conditions ofAcinetobacter. We separated10colonization strians and31infection strians.According to analysis the clinical infection risk factors, discuss the host ofcolonization and infection strians’s difference in the clinical. According to theclinical pulmonary infection score and result of quantitative culture, the striandivided into two groups: the infection group and colonization group. The CPISscore contain: temperature, extracellular leukocyte count, the purulentsecretion of airway, oxygenation index, chest imaging findings, airwayaspirates gram stain and culture results. When CPIS score>6and result ofquantitative culture>106CFU/ml can diagnosis of ventilator-associatedpneumonia. Study the relationship between the expression of out membranevirulence protein (OMPA/BauA) and the pathogenicity in the resistance ofacinetobacter baumannii in the different conditions.Methods:1Bacterial isolate source: A total of42clinical isolates of Acinetobacterbaumannii were obtained from dec.2011to mar.2012in four hospitals of hebei province.2Antimicrobial susceptibility: The Kirby-Bauer method were performedto detect the susceptibility of cefoperazone/sulbactam, cefoperazone,piperacillin, ceftazidime, biapenem, amikacin, ciprofloxacin, minocycline,levofloxacin, cefotaxime, gentamicin, chloramphenicol, imipenem, aztreonam,selectrin. The antibiotics susceptibility test was performed according to theAmerican CLSI2008standard.3Analysis the clinical risk factors in the patients: According to antimicrobial susceptibility Multidrug-resistant, Pandrug-resistant, Extensive-resistant of acinetobacter baumannii were collected. According to the clinicalpulmonary infection score and result of quantitative culture,10colonizationstrians and32infection strians were separated, and though compairingpatients’ clinnical data, the difference of clinical risk factors between the twogroups were analysised4PCR amplification of the genes of out membrane virulence protein(OMPA/BauA): Acroding to the sequence published on GenBank, specificprimers for Ompa(AY485227)/BauA(AY571146) genes were designed. PCRswere carried out with Ompa gene forward primer, OMPA15’-ATTACGACG-GAAATTGTAAGTAATTT-3’, located at+1~+26bp and reverse primer,OMP25’-CGACTCGTTAGAGTCGCTTTTTTATG-3’ located at+1291~+1317bp the BauA gene forward primer, OMPA15’-TGCAAGCCCAACCT-CACT-3’ located at+4060~+4078bp; and reverse primer, OMP25’-TTCTC-CAGACTTAGGGA-3’ located at+6642~+6660bp, for PCRamplification. PCR products were analyzed on a0.8%agarose gel.5Sequence datas were analyzed of PCR prodoucts.Results:1Antibiotic susceptibility: We use Kirby-Bauer method to detect the42clinical isolates, they all show Multidrug-resistant, among this the drugresistant rate of the acinetobacter baumannii to cefoperazone/sulbactam were30.95%. It is the lowest drug resistant rate. The drug resistant rate tocefotaxime were95.23%, the drug resistant rate to cefoperazone were88.10%.The drug resistant rate of acinetobacter baumannii to aztreonam andminocycline were97.60%and78.57%and the drug resistant rate ofacinetobacter baumannii to gentamicin, amikacin were85.72%, the drugresistant rate of acinetobacter baumannii to piperacillin,1evofloxacin were all83.34%, and to cefepime, ceftazidime were76.20%the drug resistant rate ofacinetobacter baumannii to selectrin, were73.81%, the drug resistant rate ofacinetobacter baumannii to imipenem, biapenem were73.81%and92.86%; thedrug resistant rate of acinetobacter baumanni to chloramphenicol and ciprofloxacin were69.05%and90.48%.2Analysis the clinical risk factors in the patients: According to theanalysis of clinical high risk factors by reviewing the medical records andclinical interventions of infection and colonization patients,(medical recordscontain: age, gender, medical comorbidities, number of days in intensive careunit,presence and duration of intensive procedures, prognosis, etal.), the42strains were divided into two groups:10of which being in the colonizationgroup, and32in the infection group. The most frequently identifiedpredisposing actors were length of intensive care unit stay, mechanicalventilation, and other invasive procedures. The most common comorbidconditions were: cerebrovascular disease and chronic obstructive pulmonarydisease. For the clinical data of the two groups, it is no statistical significance(p>0.05). The mortality rate of infection group was higher than that of thecolonization group, though the difference had no statistical significance.(15.66%vs.10%, p>0.05). But in the ICU patients who were separated intothe two groups, the length of ICU stay of the infection group is longer thanthat of the colonization group (p<0.05). It is statistically significant.3The results of PCR: BauA colonization group (positive rate:70%,negative rate:30%), infection group (positive rate:53.13%, negative rate:46.87%). Through Chi-square test statistical method analyze, p>0.05. Ompacolonization group:(positive rate:80%, negative rate:20%), infection group:(positive rate:87.5%, negative rate:12.5%). Through Chi-square teststatistical method analyze, p>0.05, so it is no statistical significance.Conclusions:1This experiment analyzed the drug resistance of acinetobacterbaumannii in the four hospitals in He bei Provence through the method of drugsensitive test. The lowest resistant rate of acinetobacter baumannii iscefoperazone/sulbactam. The highest is to aztreonam, while the resistant rateto imipenem and biapenem reached73.81%and92.86%respectively.2The test shows that there is no significant difference between the twogroups in clinical risk factors and mortality rate. However, difference in the length of ICU stay is statistically significant. Indicating that the prolongedICU stay increases the chances of invasive infection. Other distinctionsbetween the two groups include: the epidemic phenotype, other virulenceaspects, or the immunization level of patients.3No significant differences was found after PCR molecular biologytechnology analyses of membrane protein(Ompa) and iron related outermembrane transport protein(BauA) between the two groups. Thus, we are yetto determine if the virulence of pan-resistant Acinetobacter baumannii arerelated to these proteins. There is the possibility that the it might be closer tiedto other virulence proteins or the immunization level of patients. |
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