Objective To investigate the drug resistance and homogeneous analysis of Acinetobacter baumanii in emergency intensive care unit ( EICU) . Methods Four multidrug-resistant Acinetobacter baumannii ( MDR-Ab) strains isolated fromnosocomial inpatients fromJuly 25 to September 7 in 2009 were collected and tested for drug sensitivity and MIC determination as well. The A. baumannii isolates were typed with pulsed-field gel electrophoresis ( PFGE) to determine whether they derived fromthe same clone.Results Four isolates from nosocomial inpatients were resistant to multiple antibiotics including carbapenem. The PFGE types identified from four isolates were A and B. The A. baumannii isolates did not derived from the same clone. Conclusion The prevalence of nosocomial infection is not due to transmission of the same strains among different individuals in EICU.
Objective To study the risk factors and prognosis of hospital acquired pneumonia( HAP)caused by carbapenem-resistant Acinetobacter baumannii( CRAB) . Methods By a case-control study, the data of 44 cases of HAP caused by CRAB fromJan 2005 to Dec 2007 in Nanfang Hospital were analyzed. 66 cases of HAP caused by Carbapenem-susceptible A. baumannii ( CSAB) were selected randomly at the same time as control. Univariate analysis( T test and chi-square test) and multivariate logistic regression were used for statistics analysis. Results Univariate analysis revealed that five factors associated with the infection caused by CRAB were APACHE Ⅱ score ≥ 16, chronic pulmonary disease ( COPD/ bronchiectasis ) , imipenem/meropenem and fluoroquinolone used 15 days before isolation of CRAB, and early combination therapy of antibiotics. Multivariate logistic regression analysis identified two independent factors as APACHEⅡ score ≥16( OR=6. 41, 95% CI 2. 20-18. 67) and imipenem/meropenemused 15 days before isolation of CRAB( OR =6. 33,95% CI 1. 83-21. 87) . Of 44 cases of CRAB infections, 14 patients died and 30 patients survived. Univariate analysis revealed that two factors associated with poor prognosis were organ failure and clinical pulmonary infection score( CPIS) rise after three-day treatment. According to multivariate logistic regression analysis, only CPIS rise after three-day treatment ( OR =7. 01, 95% CI 1. 23-40. 03) was an independent predictive factor. Conclusions APACHEⅡ score ≥ 16 and imipenem/meropenem used 15 days before isolation of CRAB were independent risk factors for CRAB infection. CPIS rise after three-day treatment was a predictive factor for the prognosis of CRAB infection.
ObjectiveTo detect the in vitro susceptibility of common clinical multidrug-resistant bacteria to tigecycline by disk diffusion (KB), minimum inhibitory concentrations (MIC) test strip (MTS) and Vitek 2 Compact methods, in order to evaluate the accuracy of the three different susceptibility testing methods. MethodsA total of 140 multidrug-resistant isolates (excluding Pseudomonas aeruginosa) were collected retrospectively from West China Hospital between January 2014 and March 2015. The inhibitory zone diameters and MIC of tigecycline were determined by KB, Vitek 2 Compact system and MTS respectively. The results of Vitek 2 Compact system and KB method were compared with that of MTS. ResultsAmong the 140 multidrug-resistant isolates, 119 were Acinetobacter baumannii, and 21 were Enterobacteriaceae. According to the US Food and Drug Administration standards, the sensitivity rates of 119 Acinetobacter baumannii isolates to tigecycline were 88.2%, 85.7%, and 90.8% respectively for KB method, Vitek 2 Compact system and MTS, and those of 21 Enterobacteriaceae were 76.2%, 81.0%, and 81.0%, respectively. ConclusionsTigecycline displays effective in vitro antibacterial activity to clinical common multidrug-resistant bacteria (excluding Pseudomonas aeruginosa), but different susceptibility testing methods have shown different susceptibility rates. For Acinetobacter baumannii, KB method is superior to Vitek 2 Compact system, and for Enterobacteriaceae, Vitek 2 Compact system is superior to KB method.
ObjectiveTo evaluate the diagnostic value of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) level in bronchoalveolar lavage fluid (BALF) for discrimination of Acinetobacter baumannii (A. baumannii) colonization from infection.MethodsSixty patients with tracheal intubation or tracheotomy who were admitted in intensive care unit from July 2016 to July 2018, were divided into an infection group (n=20), a colonization group (n=20) and a control group (n=20). The serum and BALF samples were collected from the patients on the day when lower respiratory tract sample culture was positive so as to detect sTREM-1, serum procalcitonin (PCT) and interleukin-6 (IL-6). The value of serum PCT, IL-6, sTREM-1 and BALF sTREM-1 in differentiation of infection or colonization for A. baumannii was analyzed by mean of receiver operating characteristic (ROC) curve.ResultsThere were no significant differences in gender composition, age or Glasgow coma score among the three groups (P>0.05). The clinical pulmonary infection score (CPIS) of the infection group was higher than that in the control group (P<0.05). Compared with the control group, while the sTREM-1 concentration of BALF with A. baumannii colonization increased significantly but levels of PCT, IL-6 and sTREM-1 remained unchanged in serum. The levels of PCT, IL-6 and sTREM-1 in serum, and sTREM-1 in BALF increased significantly in the infection group (P<0.001). Compared with the colonization group, the levels of PCT, IL-6 and sTREM-1 in serum, and sTREM-1 in BALF increased significantly in the infection group (P<0.05). The area under the ROC curve (AUC) of serum PCT was 0.67 with the sensitivity of 0.55 and the specificity of 0.90 (95%CI 0.52 - 0.82). AUC of serum IL-6 was 0.72 with the sensitivity of 0.60 and the specificity of 0.95 (95%CI 0.58 - 0.85). AUC of serum sTREM-1 was 0.72 with the sensitivity of 0.75 and the specificity of 0.60 (95%CI 0.55 - 0.85). AUC of sTREM-1 in BALF was 0.92 with the sensitivity of 0.95 and the specificity of 0.70 (95%CI 0.79 - 0.98). The diagnostic accuracy of sTREM-1 in BALF was higher than that of PCT, IL-6 and sTREM-1 in serum (P<0.05).ConclusionssTREM-1 in BALF has good diagnostic performance in differentiating patients with infection of colonization for A. baumannii. Its sensitivity and specificity are higher than serum PCT, IL-6 and sTREM-1.
ObjectivesTo detect the admission rate and hospital acquired rate of carbapenem-resistant Klebsiella pneumoniae (CRKP) and carbapenem-resistant Acinetobacter baumannii (CRAB) of active surveillance in Emergency Intensive Care Unit patients of West China Hospital of Sichuan University, to examine whether rectal colonization of CRKP and CRAB are associated with nosocomial infection, so as to provide a scientific basis for the prevention and control of CRKP and CRAB.MethodsA nested case-control study was conducted between April and September 2018 in Emergency Intensive Care Unit. Rectal swabs were obtained to screen CRAB and CRKP, and the admission rate of colonization was calculated. According to whether infected with CRKP/CRAB, the patients were divided into case group (infection group) and control group (noninfection group) to determine whether colonization of CRKP/CRAB were independent risk factors for nosocomial infection using logistic regression model.ResultsThe admission rate of CRKP and CRAB patients were 4.08% (18/441) and 8.78% (38/433), and the nosocomial infection rate was 3.63% (16/441) and 18.01% (78/433) separately. Multivariate analysis showed that rectal colonization of CRKP [odds ratio=5.438, 95% confidence interval (1.643, 17.999), P=0.006] was an independent risk factor for nosocomial infection. However, there was no statistical correlation between rectal colonization of CRAB and nosocomial infection [odds ratio=1.449, 95% confidence interval (0.714, 2.942), P=0.305].ConclusionsThe rectal colonization rate of CRAB is higher than that of CRKP, but it does not increase the risk of CRAB infection in patients. Rectal colonization of CRKP is an important factor for infection of patients. Therefore, early detection of CRKP through active surveillance and taking control measures can help reduce the risk of its spread in the hospital.
ObjectiveTo investigate clinical characteristics and influencing factors of lower respiratory tract infection of Acinetobacter baumannii (AB-LRTI) in respiratory intensive care unit (RICU).MethodsClinical data were collected from 204 RICU patients who were isolated Acinetobacter baumannii (AB). The bacteriological specimens were derived from sputum, bronchoscopic endotracheal aspiration, bronchoalveolar lavage fluid, pleural effusion and blood. The definition of bacterial colonization was based on the responsible criteria from Centers for Disease Control and Prevention/National Medical Safety Network (CDC/NHSN). The patients were divided into three groups as follows, AB colonization group (only AB was isolated, n=40); simple AB-LRTI group (only AB was isolated and defined as infection, n=63), AB with another bacteria LRTI group (AB and another pathogen were isolated simultaneously, n=101). The epidemiology, clinical characteristics and influencing factors of each group were analyzed and compared. ResultsCompared with the AB colonization group, the AB with another bacteria LRTI group had higher proportion of patients with immunosuppression, specimens from sputum and bronchoalveolar lavage fluid, more than 4 invasive procedures, 90-day mortality, white blood cell count >10×109/L (or <4×109/L), neutrophil percent >75% (or <40%), lymphocyte count <1.1×109/L, platelet count <100×109/L, albumin <30 g/L, high sensitivity C-reactive protein >10 mg/L, and neutrophil-to-lymphocyte ratio (NLR). The frequency of bronchoscopy and days of infusing carbapenem within 90 days before isolating AB, the Acute Physiology and Chronic Health Evaluation Ⅱ score, the proportion of patients with invasive mechanical ventilation and the duration of invasive mechanical ventilation in the AB with another pathogen LRTI group were higher than those in the AB colonization group (all P<0.05). Days of infusing carbapenem and β-lactams/β-lactamase inhibitors within 90 days before isolating AB, proportion of septic shock, NLR and 90-day mortality of the patients from the AB with another pathogen LRTI group were more than those in the simple AB-LRTI group (all P<0.05). After regression analysis, more than 4 invasive procedures, or immunosuppression, or with more days of infusing carbapenem within 90 days before isolating AB were all the independent risk factors for AB-LRTI.ConclusionsThere are significant differences in epidemiology, clinical symptoms and laboratory indicators between simple AB-LRTI, AB with another pathogen LRTI and AB colonization in RICU patients. For RICU patients, who suffered more than 4 invasive procedures, immunosuppression, or with more days of infusing carbapenem within 90 days before isolating AB, are more susceptible to AB-LRTI.
ObjectiveTo study the clinical distribution and the change of drug resistance of Acinetobacter baumannii from different inpatient specimens sources during 2008 to 2012, and to provide guidance for rational use of antibiotics. MethodsThe identification of Acinetobacter baumannii was conducted by VITEK-2 based on clinical and laboratory standards institute (CLSI) guideline between January 2008 and December 2012. The susceptibility of antibiotics was determined by K-B test, and data analysis was conducted by Excel and SAS. ResultsA total of 3 139 stains of Acinetobacter baumannii were isolated from 2013 patients during this period. The Acinetobacter baumannii was mainly obtained from the Burn ward, Intensive Care Unit ward and Thoracic ward. Sputum was the most specimens of Acinetobacter baumannii, accounting for 48.4%. The drug resistance rates of Acinetobacter baumannii to most of the antimicrobial agents were more than 55%. Compound antibacterial is more effective than the single drug ingredient. Compared with other antimicrobial agents, β-lactams/β-lactamase inhibitor compound and carbapenems antimicrobial agents were more sensitive. ConclusionThe drug resistance of Acinetobacter baumannii is serious and has differences among hospitals. Clinicians should monitor the drug resistance of Acinetobacter baumannii timely and choose proper antibiotics according to the results of drug sensitivity.
Objective To investigate the predictors for carbapenem-resistant Acinetobacter baumannii, Enterobacteriaceae and Pseudomonas aeruginosa (CR-AEP) as the pathogens of bloodstream infection (BSI) for intensive care unit (ICU) patients. Methods A retrospective case-control study based on ICU- healthcare-associated infection (HAI) research database was carried out. The patients who have been admitted to the central ICU between 2015 and 2019 in the ICU-HAI research database of West China Hospital of Sichuan University were selected. The included patients were divided into two groups, of which the patients with ICU-acquired BSI due to CR-AEP were the case group and the patients with BSI due to the pathogens other than CR-AEP were the control group. The clinical features of the two groups of patients were compared. Logistic regression model was used to identify the predictors of BSI due to CR-AEP.ResultsA total of 197 patients with BSI were included, including 83 cases in the case group and 114 cases in the control group. A total of 214 strains of pathogenic bacteria were isolated from the 197 BSI cases, including 86 CR-AEP strains. The results of multivariate logistic regression analysis showed that previous use of tigecycline [odds ratio (OR)=2.490, 95% confidence interval (CI) (1.141, 5.436), P=0.022] was associated with higher possibility for CR-AEP as the pathogens of BSI in ICU patients with BSI, while previous use of antipseudomonal penicillin [OR=0.497, 95%CI (0.256, 0.964), P=0.039] was associated with lower possibility for that. Conclusion Previous use of tigecycline or antipseudomonal penicillin is the predictor for CR-AEP as the pathogens of BSI in ICU patients with BSI.
Objective To evaluate the clinical effects and safety of polymyxin B on ventilator-associated pneumonia caused by pandrug-resistant Acinetobacter baumannii (PDR-AB) in patients with chronic obstructive pulmonary disease (COPD). Methods COPD patients who were diagnosed as ventilator-associated pneumonia caused by PDR-AB and treated with polymyxin B between January 2015 and August 2016 in this hospital were included in this retrospective study. The patients’ symptoms, vital signs, and the results of laboratory examinations were recorded before and after treatment. The clinical cure rates, microbiological eradication rates, mortality and safety were also measured. Results A total of 11 cases were included in this study. Mean time of therapy was 10 days, ranged 8-13 days. After treatment with polymyxin B, most of the patients’ clinical symptoms, signs, and results of laboratory tests as well as imaging examinations were significantly improved. Seven cases had clinical response, and the clinical efficacy rate was 63.6%; 8 cases achieved bacteriological eradication, with the bacteriological eradication rate of 72.7%. Four patients died, and the overall mortality was 36.4%. Only 1 case discontinued treatment with polymyxin B because of the drug fever. Conclusions Polymyxin B might be an alternative option for COPD patients with ventilator-associated pneumonia caused by PDR-AB, who is non-responder to prior antimicrobial therapy. However, this method should be evaluated cautiously in prospective well-controlled studies.