OBJECTIVETo monitor genotypes and drug-resistance trend of Acinetobacter baumannii (AB) isolated from burn wards.

METHODSTwenty-six strains of AB isolated from wound secretion, venous catheter, and blood were collected from burn patients hospitalized in our burn wards from November 2008 to February 2009, and June to September 2010. Homogeneous genotype analysis was performed with repetitive extragenic palindromic PCR, and drug-resistance rate to 13 antibiotics including amikacin, gentamicin, etc., which were commonly used in clinic, was tested by K-B paper disk diffusion. The data of drug-resistance rate were processed with chi-square test.

RESULTS(1) Sixteen AB strains were multi-drug resistant (MDR), 9 AB strains were pan-drug resistant (PDR). Among all strains, the resistance rate to gentamicin, piperacillin, piperacillin/tazobactam, cefuroxime, cefotaxime, ceftazidime, cefepime, ciprofloxacin, imipenem, and meropenem was respectively higher than 90.00%; the resistance rate against cefoperazone/sulbactam was the lowest (11/26, 42.31%). There were obvious difference among the drug-resistance rates of AB strains to 13 antibiotics (with rates from 42.31% to 100.00%, χ(2) = 97.371, P < 0.05). (2) There were 7 genotypes among 26 AB strains, respectively type A (17), type B (3), type C (2), type D (1), type E (1), type F (1), and type G (1). Out of the 17 AB strains in A genotype, 1 strain was from 2008, 1 strain was from 2009, 15 strains were from 2010, and among them 11 strains were collected from wound secretion and 6 strains were obtained from blood and venous catheter.

CONCLUSIONSAB strains in A genotype are dominant in our burn wards in recent years, which are MDR or PDR to commonly used antibiotics. Cefoperazone/sulbactam is the drug of choice for burn patients with AB infection.

Acinetobacter Infections ; epidemiology ; microbiology ; Acinetobacter baumannii ; drug effects ; genetics ; Burns ; microbiology ; Cross Infection ; epidemiology ; microbiology ; Drug Resistance, Multiple, Bacterial ; Genes, Bacterial ; Humans

Infections caused by Acinetobacter baumannii (AB) have emerged as a knotty clinical problem in the burn wards due to its omni-resistance to antibiotics and high prevalence. Although our knowledge in regard to the pathogenesis and the resistance mechanisms of AB is increasing, the available treatment remains much limited. Measures to effectively control nosocomial infection are warranted. Meanwhile, development of novel therapeutic agents or combination of antibiotics should be considered.
Acinetobacter Infections ; epidemiology ; Acinetobacter baumannii ; drug effects ; Anti-Infective Agents ; pharmacology ; Burns ; microbiology ; Drug Resistance, Multiple, Bacterial ; Humans

Acinetobacter Infections ; epidemiology ; microbiology ; Acinetobacter baumannii ; isolation & purification ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Cross Infection ; epidemiology ; microbiology ; Female ; Hematologic Diseases ; microbiology ; Hospital Units ; Humans ; Male ; Middle Aged ; Prevalence ; Young Adult

OBJECTIVETo study the clinical distribution characteristics and vicissitude of antibiotic resistance of Acinetobacter baumannii (AB), and to look for the risk factors of AB infection in order to provide reasonable reference for the prevention and treatment of its infection.

METHODSSpecimens of blood, venous catheters, sputum, wound exudates and pharyngeal swabs from 156 patients hospitalized in our burn ICU from January 2006 to December 2008 were collected and cultured. The clinical distribution and antibiotic resistance of AB were determined and analyzed. The risk factors related to AB infection were analyzed. Drug resistance rate data were processed with WHONET 5.3 software; the other data were processed with chi-square test and Logistic regression analysis.

RESULTSNinety-two strains of AB were identified during the three years from different kinds of specimens, with 41 (44.6%) from wound exudates, 14 (15.2%) from pharyngeal swabs and sputum respectively, 13 (14.1%) from blood, and 10 (10.9%) from venous catheters. AB accounted for 23.1% (30/130), 27.5% (25/91), 28.2% (37/131) respectively among the strains detected in 2006, 2007, and 2008. During the three years, except for imipenem and cefoperazone/sulbactam, the average resistance rates of AB to other ten commonly used antibiotics were all above 50.0%. Burn area (χ(2) = 24.374, P = 0.000), mechanical ventilation (χ(2) = 8.968, P = 0.003), duration of use of antibiotics (χ(2) = 3.981, P = 0.046), and deep venous catheterization (χ(2) = 9.170, P = 0.002) were the risk factors of AB infection, and the former two were independent risk factors.

CONCLUSIONSThere is a pan-drug resistance tendency of AB in our burn ICU, and the positive culture rates are increasing in recent years. Disinfection and isolation measures, appropriate use of antibiotics, avoidance of invasive performances such as deep venous catheterization and tracheostomy, or shortening their duration are important means to prevent and control infection of AB.

Acinetobacter Infections ; epidemiology ; Acinetobacter baumannii ; drug effects ; isolation & purification ; Adult ; Burns ; epidemiology ; microbiology ; China ; epidemiology ; Cross Infection ; microbiology ; Drug Resistance, Bacterial ; Female ; Humans ; Intensive Care Units ; statistics & numerical data ; Male ; Young Adult

OBJECTIVETo analyse the plasmid-mediated SHV type beta-lactamases-encoding genes sequence and to identify its subtype of multiple-drug-resistant acinetobacter baumannii isolated from Huzhou district, Zhejiang province, China.

METHODSSixty strains of acinetobacter baumannii were isolated from hospitalized patients between Jul, 2000 and Dec, 2002. Susceptibility of antimicrobial agents and confirmatory tests for Extended-spectrum beta-lactamases (ESBLs) were tested by microdilute method. SHV type beta-lactamases-encoding genes were tested by polymerase chain reaction (PCR). SHV sequences of acinetobacter baumannii HZ02 and HZ10 strains were detected by ABI automated sequencer and were analysed to compare with SHV genes that had been published in GenBank.

RESULTSEighteen (30.0%) strains of acinetobacter baumannii isolated between Jun, 2001 and Jan, 2002 were carrying SHV beta-lactamases resistant gene of plasmids. Detected SHV sequences of acinetobacter baumannii HZ02 strain and HZ10 strain had 825 and 833 nucleotides respectively and had the same gene sequence as the gene encoding SHV-12 subtype of ESBLs discovered in Switzerland.

CONCLUSIONSThirty percentage of the clinically isolated acinetobacter baumannii were carrying SHV type (extended-spectrum) beta-lactamases resistant gene of plasmids and causing an outbreak in hospital and was discovered to have carried the strains of SHV-12 subtype producing ESBLs gene in acinetobacter baumannii which was the first reported case in the world.

Acinetobacter Infections ; epidemiology ; microbiology ; Acinetobacter baumannii ; enzymology ; genetics ; isolation & purification ; Amino Acid Sequence ; Base Sequence ; China ; epidemiology ; DNA, Bacterial ; genetics ; isolation & purification ; Drug Resistance, Multiple ; Humans ; Molecular Epidemiology ; Molecular Sequence Data ; Sequence Analysis, DNA ; beta-Lactamases ; classification ; genetics

OBJECTIVE: To survey antibiotic resistance of clinical isolates of Acinetobacter baumannii in Changsha and to investigate molecular epidemiological characteristics of carbapenem-resistant Acinetobacter baumannii. METHODS: A total of 205 non-duplicated, clinical isolates of Acinetabacter baumannii from 10 general hospitals in Changsha were collected from March 2010 to December 2010. The K-B disk diffusion method was applied for the drug-susceptibility test; a modified, double-disk synergy test was used to detect metallo-β-lactamase (MBL), and a modified Hodge test was used for the screening of carbapenemase. PCR was used to amplify carbapenemase genes (including OXA-23, OXA-24, OXA-51, IMP-1, and VIM-2) and the positive products were sequenced. Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) was used for DNA typing and test of homology. RESULTS: Of the 18 antibiotics tested, 14 had a high rate of resistance (>50% of the isolates tested), with piperacillin the highest (80.5% of strains), and cefoperazone/sulbactam the lowest (2.5%). In total, 115 carbapenem-resistant Acinetobacter baumannii strains were confirmed, but their MBL phenotype and genes were all negative. Seventy-one positive strains were detected by the modified Hodge test, among which 64 strains were OXA-23-positive. All the 115 strains were positive for the amplification of the OXA-51 gene, and no strain was found which carried OXA-24 or OXA-58 gene. Seven genomic types were included in the 115 Acinetobacter baumannii. The major prevalence types were Type B ( 72 strains) and Type A (19 strains). CONCLUSION Multiple drug resistance of clinically isolated Acinetobacter baumannii is a serious problem in Changsha. Production of OXA-23 and OXA-51 carbapenemases is an important mechanism of resistance to carbapenem antibiotics, and there is prevalence of the same clones in these carbapenem-resistant strains.
Acinetobacter Infections ; epidemiology ; microbiology ; Acinetobacter baumannii ; drug effects ; genetics ; isolation & purification ; Carbapenems ; pharmacology ; China ; epidemiology ; DNA, Bacterial ; genetics ; Drug Resistance, Multiple, Bacterial ; genetics ; Humans ; Molecular Epidemiology ; Piperacillin ; pharmacology ; Polymerase Chain Reaction ; methods

OBJECTIVETo analyze the detection, drug resistance, and status of infection of Acinetobacter baumannii (AB) in burn ICU during 3 years.

METHODSA total of 2 010 specimens of wound secretion, blood, venous catheter attachment, sputum, stool and urine were collected from 505 burn patients hospitalized in our burn ICU from January 2011 to December 2013, and bacterial culture was performed. Pathogens were identified by automatic microorganism identifying and drug sensitivity analyzer. Drug resistance of all the obtained AB to 16 antibiotics commonly used in clinic, including cefoperazone/sulbactam, polymyxin, etc., was tested with K-B paper disk diffusion method. Patients with AB infection were ascertained. The WHONET 5.6 software was used to analyze the distribution of pathogens during 3 years, the isolation of AB with different sources and the status of drug resistance of AB to 16 antibiotics each year, and the status of patients with AB infection, and their outcome.

RESULTSA total of 961 strains of pathogens were isolated, among which 185 (19.25%) strains were Gram positive cocci, 728 (75.75%) strains were Gram negative bacilli, and 48 (4.99%) strains were fungi. A total of 172 strains of AB were isolated, ranking the second place among all the detected pathogens, with 67 (38.95%) strains from wound secretion, 11 (6.40%) strains from blood, 23 (13.37%) strains from venous catheter attachment, and 71 (41.28%) strains from sputum, no AB strain was isolated from feces or urine. The AB strains were found sensitive to polymyxin and with relatively low drug resistance rate to minocycline, while the drug resistance rates were over 80.0% to the other 14 antibiotics commonly used in clinic in 2013. AB culture of wound secretion was positive in 27 patients. Among them, 7 patients suffered from wound infection, and the wound infection was caused by AB in 1 out of the 7 patients. AB culture of blood was positive in 7 patients. Among them, 3 patients suffered from bloodstream infection, and the infection was due to AB invasion in 1 out of the 3 patients. AB culture of venous catheter attachment was positive in 20 patients. Among them, 8 patients suffered from bloodstream infection, and the infection was due to AB invasion in 1 out of the 8 patients. AB culture of sputum was positive in 35 patients. Among them, 13 patients suffered from ventilatory associated pneumonia, and 2 out of the 13 patients were diagnosed as AB infection. A total of 69 patients were AB culture positive, among them 64 patients were cured, 2 patients were transferred to other hospitals, and 3 patients died, with the mortality rate of 4.35%.

CONCLUSIONSAB in our burn ICU has a high detection rate and extensive drug resistance in above-mentioned 3 years. However, AB was mainly colonized in patients with extensive burns with a low mortality rate.

Acinetobacter Infections ; drug therapy ; epidemiology ; microbiology ; Acinetobacter baumannii ; drug effects ; isolation & purification ; Anti-Bacterial Agents ; pharmacology ; Burns ; microbiology ; Cross Infection ; Drug Resistance ; Gram-Negative Bacteria ; isolation & purification ; Humans ; Intensive Care Units ; Microbial Sensitivity Tests

Monitoring temporal trends of antimicrobial resistance can provide useful information for the empirical selection of antimicrobial agents to treat infected patients and for the control of nosocomial infections. In this study, we analyzed antimicrobial resistance of clinically relevant bacteria in 2003 at Korean hospitals and at a commercial laboratory. The following organism-antimicrobial agent resistance combinations were very prevalent: oxacillin-resistant Staphylococcus aureus (68%), expanded-spectrum cephalosporin-resistant Klebsiella pneumoniae (25%), and fluoroquinolone-resistant Escherichia coli (33%), Acinetobacter spp. (58%), and Pseudomonas aeruginosa (40%). Moreover, gradual increases in vancomycin-resistant Enterococcus faecium (20%), cefoxitin-resistant E. coli (10%) and K. pneumoniae (23%), and imipenem-resistant P. aeruginosa (20%) and Acinetobacter spp. (13%) were also observed. The resistance rates of Acinetobacter spp. to most antimicrobial agents at hospitals and at the commercial laboratory were similar. Among the Acinetobacter spp. isolated at a tertiary-care hospital, 46.2% were multidrug-resistant to 9-12 of 13 antimicrobial agents, and 18.3% were panresistant. The exclusion of duplicate isolates at a tertiary-care hospital significantly lowered the proportion of oxacillin-resistant S. aureus, vancomycin-resistant E. faecium, and fluoroquinolone-resistant E. coli.
Vancomycin Resistance ; Vancomycin/pharmacology ; Population Surveillance ; Microbial Sensitivity Tests ; Korea/epidemiology ; Klebsiella pneumoniae/drug effects/isolation & purification ; Klebsiella Infections/drug therapy/epidemiology/microbiology ; Imipenem/pharmacology ; Humans ; Gram-Positive Bacterial Infections/drug therapy/epidemiology/*microbiology ; Gram-Negative Bacterial Infections/drug therapy/epidemiology/*microbiology ; Gammaproteobacteria/*drug effects/isolation & purification ; Fluoroquinolones/pharmacology ; Enterococcus faecium/*drug effects/isolation & purification ; *Drug Resistance, Bacterial ; Anti-Bacterial Agents/*pharmacology ; Amikacin/pharmacology ; Acinetobacter Infections/drug therapy/epidemiology/microbiology ; Acinetobacter/drug effects/isolation & purification

BACKGROUND: The aims of this study were to understand the molecular epidemiology of integron-associated gene cassettes in Acinetobacter baumannii across four hospitals in northern Taiwan and to clarify the relationship between the presence of integrons and antibiotic-resistant phenotypes. METHODS: Sixty-five A. baumannii isolates, collected from the patients of four regional hospitals in northern Taiwan in 2009, were tested for the presence of integrons and their associated gene cassettes. The susceptibility difference between integron-positive and integron-negative A. baumannii strains was analyzed. Antibiotic-resistant phenotypes among A. baumannii with different types of gene cassette array combinations were also compared. RESULTS: Around 72% of the A. baumannii isolates carried class 1 integrase genes. Despite this, only three gene cassette arrays were found in the integrons. Integron-positive strains were significantly more resistant to all the tested antibiotics than the integrase-negative strains. All the four types of A. baumannii with different gene cassette array combinations were multidrug-resistant in nature. Gene cassette array aacA4-catB8-aadA1 existed in all the integron-positive A. baumannii isolates. Repetitive-sequence-based PCR (rep-PCR) results revealed the prevalence of one major cluster of imipenem-resistant A. baumannii strains (84%) in the four regional hospitals. CONCLUSIONS: The presence of integrons with associated antimicrobial resistance gene cassettes can be used as a representative marker of multidrug resistance in A. baumannii. Some prevalent gene cassette arrays may exist among epidemiologically unrelated A. baumannii strains.
Acinetobacter Infections/epidemiology/*microbiology ; Acinetobacter baumannii/drug effects/*genetics/isolation & purification ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; DNA, Bacterial/analysis ; Drug Resistance, Bacterial ; Humans ; Imipenem/pharmacology ; Integrases/genetics ; Integrons/*genetics ; Microbial Sensitivity Tests ; Multiplex Polymerase Chain Reaction ; Taiwan/epidemiology

OBJECTIVETo determine the risk factors and outcomes of imipenem-resistant Acinetobacter baumannii (IRAB) bloodstream infection (BSI) cases, since there is very little publication on Acinetobacter baumannii infections from Malaysia.

METHODSA cross sectional study of 41 cases (73.2%) of imipenem-sensitive Acinetobacter baumanii (ISAB) and 15 cases (26.8%) of IRAB was conducted in a teaching hospital which was located at North-Eastern state of Malaysia.

RESULTSThere was no independent risk factor for IRAB BSI identified but IRAB BSI was significantly associated with longer bacteraemic days [OR 1.23 (95% CI 1.01, 1.50)]. Although prior use of carbepenems and cephalosporin were higher among IRAB than ISAB group, statistically they were not significant. There was no significant difference in term of outcomes between the two groups.

CONCLUSIONSAlthough statistically not significant, this analysis compliments previous publication highlighting the importance of appropriate empiric antibiotic usage in hospital especially carbepenems and need further evaluation with bigger subjects.

Acinetobacter Infections ; drug therapy ; epidemiology ; microbiology ; Acinetobacter baumannii ; drug effects ; isolation & purification ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Bacteremia ; drug therapy ; epidemiology ; microbiology ; Case-Control Studies ; Cross-Sectional Studies ; Female ; Hospitals, Teaching ; Humans ; Imipenem ; pharmacology ; therapeutic use ; Malaysia ; epidemiology ; Male ; Middle Aged ; Risk Factors ; Treatment Outcome ; Young Adult ; beta-Lactam Resistance