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Objective To summarize current status of multidrug-resistant organism (MDRO) infection in lung transplant recipients and analyze the risk factors of MDRO infection. Methods Clinical data of 321 lung transplant recipients were retrospectively analyzed. According to the incidence of postoperative MDRO infection, they were divided into the MDRO group (n=122) and non-MDRO infection group (n=199). The incidence of MDRO infection in lung transplant recipients was summarized. The risk factors of MDRO infection in lung transplant recipients were analyzed by logistic regression model. The dose-response relationship between MDRO infection and time of ventilator use was determined by restricted cubic spline model. Results Among 321 lung transplant recipients, 122 cases developed MDRO infection, with an infection rate of 38.0%. Two hundred and twenty-nine strains of pathogenic bacteria were detected in the MDRO infection group, mainly Gram-negative bacteria (92.6%), and the top three strains were carbapenem-resistant acinetobacter baumannii (46.3%), carbapenem-resistant pseudomonas aeruginosa (22.3%) and carbapenem-resistant klebsiella pneumoniae (14.8%), respectively. MDRO infection mainly consisted of lower respiratory tract infection (61.5%), followed by ventilator-associated pneumonia (26.2%). Univariate analysis showed that the risk factors of MDRO infection in lung transplant recipients were single-lung transplantation, long-time postoperative use of extracorporeal membrane oxygenation (ECMO), long operation time, long-time urinary catheterization, long-time central venous catheterization and long-time ventilator use (all P < 0.05). Multivariate logistic regression analysis indicated that single-lung transplantation and long-time ventilator use were the independent risk factors for MDRO infection in lung transplant recipients (both P < 0.05). Results of restricted cubic spline model analysis showed that the risk of infection continued to increase with the prolongation of ventilator use time within 20 d. After 20 d, prolonging the time of ventilator use failed to increase the risk of infection, showing a plateau effect. Conclusions The MDRO infection rate tends to decline in lung transplant recipients year by year. Single-lung transplantation and long-time ventilator use are the independent risk factors for MDRO infection in lung transplant recipients.
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In recent years, the bloodstream infection rate of Gram-negative bacilli has continued to increase. Among them, drug-resistant bacteria have a higher mortality rate and longer hospital stay, especially the bloodstream infection of carbapenem-resistant Acinetobacter baumannii (CRAB). Polymyxin began to be used clinically in the 1950s and has antibacterial activity against multidrug resistant and poly drug-resistant Gram-negative bacilli. It can also be used as an effective permeation agent for the cell envelope of Gram-negative bacilli. Polymyxin is reserved for microbiologically clear drug-resistant Gram-negative bacilli infections. The World Health Organization classifies polymyxin as an antimicrobial drug with clinical significance for human infections and can be used to treat drug-resistant Acinetobacter baumannii infection. This article reviews the clinical treatment of polymyxin in bloodstream infections of drug-resistant Acinetobacter baumannii, to provide reference for clinical medication.
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The clinical efficacy of polymyxins in severe infection caused by carbapenem resistant organism (CRO) has gradually been recognized, and the course of treatment is generally 2 to 4 weeks. The most common complications after intravenous injection are nephrotoxicity and neurotoxicity, however, there are few reports on the efficacy and safety of the long course use of polymyxins. A patient with carbapenem resistant Acinetobacter baumannii (CRAB) infection after neurosurgery was admitted to the department of neurosurgical intensive care unit (NICU) of Lanzhou University Second Hospital. As the family refused the excision of brain abscess and Ommaya reservoir placement, polymyxin B was given intravenous (3.0 mg·kg -1·d -1) combined with intrathecal (5 mg once daily) injection, and high-dose sulbactam (8 g/d) was intravenously injected for anti-infection therapy. Finally, the brain abscess was absorbed and the patient was successfully cured. The total course of polymyxin B was 69 days with a cumulative dosage of 7 500 mg. There were no complications such as polymyxin-related nephrotoxicity and neurotoxicity during the period, and no symptoms of respiratory inhibition or neuromuscular blockage were observed, but polymyxin-related skin pigmentation appeared about 1 month after intravenous administration of polymyxins B, which subsided after drug withdrawal. It is suggested that long course of polymyxins B is safe and effective for intracranial infection caused by CRAB.
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Background & objectives: Acinetobacter baumannii is an opportunistic pathogen responsible for causing nosocomial infections. A. baumannii develops resistance to various antimicrobial agents including carbapenems, thereby complicating the treatment. This study was performed to characterize the isolates for the presence of various ?-lactamases encoding genes and to type the isolates to compare our clones with the existing international clones across five centres in India. Methods: A total 75 non-repetitive clinical isolates of A. baumannii from five different centres were included in this study. All the isolates were confirmed as A. baumannii by bl aOXA-51-likePCR. Multiplex PCR was performed to identify the presence of extended spectrum ?-lactamases (ESBL) and carbapenemases. Multilocus sequence typing was performed to find the sequence type (ST) of the isolates. e-BURST analysis was done to assign each ST into respective clonal complex. Results: blaOXA-51-likewas present in all the 75 isolates. The predominant Class D carbapenemase was blaOXA-23-likefollowed by Class B carbapenemase, blaNDM-like. Class A carbapenemase was not observed. blaPER-likewas the predominant extended spectrum ?-lactamase. ST-848, ST-451 and ST-195 were the most common STs. Eight-novel STs were identified. e-BURST analysis showed that the 75 A. baumannii isolates were clustered into seven clonal complexes and four singletons, of which, clonal complex 208 was the largest. Interpretation & conclusions: Most of the isolates were grouped under clonal complex 208 which belongs to the international clonal lineage 2. High occurrence of ST-848 carrying blaOXA-23-likegene suggested that ST-848 could be an emerging lineage spreading carbapenem resistance in India.
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Objective • To find lytic bacteriophages which have potential to combat carbapenem-resistant Acinetobacter baumannii (CRAB) infections and analyze the biological characterizations and genomic sequences of the phages. Methods • The phages were isolated from sewage followed by amplification and purification. They were characterized by the transmission electron microscopy, the host specificity, the biological characterizations, the lysis assay in vitro and the genome sequence analysis. Results • A novel bacteriophage, SH-Ab 15599, was isolated from sewage. The electron microscope revealed SH-Ab 15599 belongs to Myoviridae. Among the 51 clinical CRAB isolates tested, 15 (29.4%) were lysed by the phage. SH-Ab 15599 was relatively stable at temperature range from 4℃ to 50℃ or between pH 6 and 9. About 90% of the phage was approximately adsorbed to the host CRAB isolate in 5 min. The one-step growth curve showed that the latent period was about 10 min and the growth period was about 20 min. The burst size was estimated at 43 pfu per infected cell. The growth of the host CRAB isolate was inhibited by the phage in vitro. The genome of SH-Ab 15599 was a linear, 143 204 bp double-stranded DNA with GC content of 38.45%. Conclusion • SH-Ab 15599 is a novel phage targeting CRAB and has potential as an alternative against CRAB infections in the future.
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Objective To investigate the clinical distribution and antimicrobial resistance characteristics of carbapenem-resistant Acinetobacterbaumannii (CRAB).Methods CRAB isolated from all inpatients in a hospital in January-December 2015 were performed retrospective analysis,antimicrobial susceptibility testing result was analyzed.Results A total of 721 AB strains were detected,231 (32.04%)of which were CRAB,isolation rates of CRAB in quarter 1-4 were 48.99% (73/149),41.98%(68/162),27.39%(63/230),and 15.00%(27/180) respectively,which showed a decreased trend (P<0.001).CRAB mainly came from sputum specimen(n=140, 60.61%),followed by secretion of wound(n=33,14.28%)and urine specimen(n=24,10.39%).CRAB mainly distributed in intensive care unit,accounting for 43.72%(n=101),following by department of neurosurgery(n=37,16.02%),and burn/plastic surgery (n=22,9.52%).Resistance rates of CRAB to ampicillin/sulbactam, gentamicin,levofloxacin, and ciprofloxacin were 85.28% -90.48%,resistance rate to tobramycin was low (19.48%),no strains were found to be resistant to polymyxin B.Conclusion Antimicrobial resistance of CRAB is serious,it is necessary to focus on management of key departments,take scientific prevention and control measures, so as to effectively reduce the incidence of healthcare-associated infection.
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Objective To investigate the distribution of carbapenem‐resistant Acinetobacter baumannii(CRAB) infections and its resistance to commonly used antibacterial drugs to provide a basis for infection control and rational use of antibacterial drugs in this area .Methods The clinical data and drug susceptibility test results in the patients with CRAB infection in our hospital from January 1 ,2013 to December 31 ,2014 were retrospectively analyzed .Results Eighteen strains of CRAB in community‐acquired in‐fection and 140 strains of CRAB in nosocomial infection were isolated ,the resistance rates to piperacillin/tazobactam ,gentamicin and tobramycin were higher than 80% ,which to ampicillin/sulbactam and levofloxacin were 64 .5% and 48 .2% respectively ,which to compound SMZ and amikacin were lower than 25% .The distribution of drug sensitivity results had no statistical difference between community CRAB infection and nosocomial CRAB infection (P>0 .05) .Conclusion The CRAB infection is mainly nosocomial in‐fection ,the empirical therapy could select compound SMZ and amikacin .
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Objective To investigate the causes of a suspected outbreak of lower respiratory tract infection (LR-TI)caused by carbapenem-resistant Acinetobacter baumannii (CRAB)in the general intensive care unit(ICU)of a hospital,and provide scientific evidence for effective control of healthcare-associated infection(HAI).Methods Epi-demiological investigation on patients infected with CRAB and on-site monitoring on ICU environmental hygiene from March 4 to 23,2014 were performed,active prevention and control measures were taken.Results A total of 7 patients developed CRAB infection,the total length of stay during epidemic period were 160 days,the infection density of LRTI was 43.75‰(7/160),4 of 5 patients at No.02 bed had CRAB LRTI.Univariate analysis revealed that adopting conventional sputum suction procedure was a risk factor;the qualified rate of bacterial count on the object surfaces was 31 .75% (20/63).CRAB was also isolated from outer frame of suction device of No.02 bed, which had the same antimicrobial pattern as CRAB from 7 patients’sputum.After taking a series of controlling measures,there was no CRAB infection case after March 24,2014,this outbreak was effectively controlled. Conclusion This suspected HAI outbreak may be caused by inadequate disinfection of outer frame of suction device contaminated by CRAB,and horizontally transmitted through manipulation of sputum suction by health care workers.Clean and disinfection of ICU environmental object surfaces is of great importance for preventing HAI.
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Objective To Screen the carbapenem-resistant acinetobacter baumannii so as to understand the drug resistance,and to analyze the outer membrane protein expression between the carbapenem-resistant Acinetobacter baumannii and the sensitive strains.Methods The twofold agar dilution method was used to screen the carbapenem-resistant acinetobacter baumannii.PCR technique was used to detect the outer membrane protein-encoding gene carO.SDS-PAGE was used to analyze the expression of outer membrane protein.Results 32 strains were carbapenem-resistant acinetobacter baumannii separated from 1 10 strains,which were 100% sensitive to polymyxin B and were resistant to other drugs with different degrees O.They all carried carO gene.There were different protein bands between the carbapenem-resistant strains and the sensitive strains,in which two protein bands of 50× 10 3 and 22×10 3 were recognized as outer membrane proteins through the analysis of SDS-PAGE.Conclusion Drug resistance of acinetobacter baumannii is serious,and the outer membrane protein expression between the carbapenem-resistant strains and the sensitive strains presents discrepancy.
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Objective To investigate the distribution characteristics and antimicrobial resistance of carbapenem-resistantAcinetobacter baumannii (CRAB),and to guide effective clinical prevention and rational antimicrobial use. Methods Data about clinically isolated CRAB between January 2009 and December 2013 were analyzed retrospec-tively,distribution and antimicrobial resistance were analyzed by WHONET 5.5 software.Results A total of 888 Acinetobacter baumannii strains were isolated,421 of which were CRAB,the isolation rate was 47.4%,the isola-tion rates in 2011 ,2012 and 2013 were all about 50.0%;CRAB strains were mainly isolated from sputum (73.4%) and mostly distributed in intensive care unit (ICU)(61 .3%),followed by neurosurgery department (12.4% ). CRAB presented highly antimicrobial resistance.Except cefotaxime and cefatriaxone,resistant rates of CRAB to the other detected antimicrobial agents(ceftazidime,cefepime,cefoperazone/sulbactam,aztreonam,imipenem,amika-cin,gentamycin,minocycline,chloramphenicol,levofloxacin,ciprofloxacin,and compound sulfamethoxazole)were all higher than non-CRAB isolates(all P ≤0.01),Compared with non-CRAB isolates,The resistant rate of CRAB to cefoperazone/sulbactam was the lowest(80.0%.Conclusion Surveillance of CRAB should be further strengthened.It is necessary to fo-cus on the control and prevention of healthcare-associated infection in ICU patients and respiratory system.
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Objective To explore the risk factors and prognosis of hospitalized patients with bloodstream infection due to carbapenem-resistant Acinetobacter baumannii (CRAB).Methods 163 patients with CRAB bloodstream in-fection from 2010 to 2013 were conducted retrospective case-control study,68 patients with bloodstream infection due to carbapenem-susceptible Acinetobacter baumannii (CSAB)during the same period were as control group. Results The independent risk factors for CRAB bloodstream infection were stay in intensive care unit(ICU)(OR, 1 .27[95%CI ,5.55-22.89])and emergency department(OR,3.57 [95%CI ,1 .67 -7.62])before infection.Pa-tients with CRAB bloodstream infection had lower 28-day survival rate than those with CSAB bloodstream infection (66.17% vs 96.95%,χ2 =15.71 ,P <0.001 ).The independent risk factors for influencing prognosis of Acineto-bacter baumannii bloodstream infection were infection of CRAB (HR 95% CI ,3.01 -67.28),blood disease(HR 95%CI ,3.77-25.97),cardiac insufficiency(HR 95%CI ,2.10-20.41),stay in ICU(HR 95%CI ,1 .01 -5.28), and age(HR 95%CI ,1 .01 -1 .04).Conclusion The independent risk factors for CRAB bloodstream infection are stay in ICU and emergency department before infection,CRAB bloodstream infection is risk factor for influencing prognosis of patients.
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Objective To provide a scientific reference for the choice of antimicrobial drugs by analyzing the distributions and the antimicrobial resistances of Carbapenem‐resistant Acinetobacter baumannii (CR‐AB) and methicillin‐resistant Staphylococcus au‐reus (MRSA) in the Northern Jiangsu People′s Hospital .Methods All the CR‐AB and the MRSA isolated from hospitalized pa‐tients from January 2011 to March 2014 were collected and analyzed .Use the disk diffusion method for antimicrobial resistance tes‐ting .Results A total of 170 CR‐AB strains and 168 MRSA strains were isolated .CR‐AB mainly distributed in the ICU ,which ac‐counting for 61 .17% (104/170) .MRSA mainly isolated in neurosurgery ,about 27 .98% (47/168) .67 .06% of CR‐AB strains and 54 .17% of MRSA strains were from Sputum specimens .The antimicrobial resistance rate of CR‐AB to most antimicrobial drugs were reached 50 .00% ,the resistance rates to cefoperazone/sulbactam (27 .65% ) ,minocycline (21 .18% ) ,amikacin (19 .41% ) and tobramycin (12 .35% ) were all less than 30 .00% ,the strain that resistant to polymyxin was not found .The sensitivity rates of MR‐SA to linezolid ,vancomycin ,and tigecycline were 100 .00% ,and the resistance rates to nitrofurantoin and kuinuputing/ dalfopristin were low (less than 2 .00% ) .Conclusion The antimicrobial resistances of CR‐AB and MRSA are serious .In order to control effec‐tively the spreading of CR‐AB ,MRSA and other multi‐drug resistant bacteria ,it′s necessary for us to strengthen the management of key departments ,and select antimicrobial drugs based on the results of drug susceptibility testing .