Acinetobacter baumannii ; classification ; genetics ; isolation & purification ; Drug Resistance, Multiple, Bacterial ; genetics ; Humans ; Phylogeny

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

BACKGROUND: Acinetobacter baumannii has a greater clinical impact and exhibits higher antimicrobial resistance rates than the non-baumannii Acinetobacter species. Therefore, the correct identification of Acinetobacter species is clinically important. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has recently become the method of choice for identifying bacterial species. The purpose of this study was to evaluate the ability of MALDI-TOF MS (Bruker Daltonics GmbH, Germany) in combination with an improved database to identify various Acinetobacter species. METHODS: A total of 729 Acinetobacter clinical isolates were investigated, including 447 A. baumannii, 146 A. nosocomialis, 78 A. pittii, 18 A. ursingii, 9 A. bereziniae, 9 A. soli, 4 A. johnsonii, 4 A. radioresistens, 3 A. gyllenbergii, 3 A. haemolyticus, 2 A. lwoffii, 2 A. junii, 2 A. venetianus, and 2 A. genomospecies 14TU. After 212 isolates were tested with the default Bruker database, the profiles of 63 additional Acinetobacter strains were added to the default database, and 517 isolates from 32 hospitals were assayed for validation. All strains in this study were confirmed by rpoB sequencing. RESULTS: The addition of the 63 Acinetobacter strains' profiles to the default Bruker database increased the overall concordance rate between MALDI-TOF MS and rpoB sequencing from 69.8% (148/212) to 100.0% (517/517). Moreover, after library modification, all previously mismatched 64 Acinetobacter strains were correctly identified. CONCLUSIONS: MALDI-TOF MS enables the prompt and accurate identification of clinically significant Acinetobacter species when used with the improved database.
Acinetobacter Infections/*microbiology/pathology ; Acinetobacter baumannii/*chemistry/classification/isolation & purification ; Bacterial Proteins/chemistry/genetics/metabolism ; Databases, Factual ; Humans ; Phylogeny ; RNA, Ribosomal, 16S/chemistry/genetics/metabolism ; *Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

The trends and types of carbapenemase-producing Gram-negative bacilli were analyzed from clinical specimens collected between 2005 and 2012 at a Korean teaching hospital. The proportions of carbapenem-resistant Acinetobacter spp. increased markedly to 66%. Metallo-beta-lactamase producers significantly decreased and the majority shifted from the bla(VIM-2) type to the bla(IMP-1) type.
Acinetobacter/classification/drug effects/*enzymology ; Acinetobacter Infections/drug therapy ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins ; Carbapenems/*pharmacology ; Drug Resistance, Microbial ; Gram-Negative Bacteria/*drug effects/enzymology/isolation & purification ; Humans ; Incidence ; Microbial Sensitivity Tests/trends ; Population Surveillance ; Pseudomonas/classification/drug effects/enzymology ; Republic of Korea/epidemiology ; beta-Lactamases/biosynthesis/*drug effects

OBJECTIVETo investigate the distribution and drug resistance of acinetobacter isolated from burn wounds.

METHODSThe acinetobacter strains were isolated and identified by routine methods. Based on the recommendation of NCCLS, AmpC enzyme was determined by cefoxiti three-dimensional test, ESBLs by disk diffusion method and bacterial susceptibility by Kirby-Bauer agar diffusion method.

RESULTSAmong the 69 strains of acinetobacter clinically isolated from burn wounds, 52 were baumannii (75.6%). The acinetobacter strains were identified to be highly resistant to 17 kinds of antibiotics. The drug resistance rate of beta-lactamase-producing strains (68.25%) was higher than that of non-beta-lactamase-producing strains (20.33%). The strains isolated in our burn ward exhibited multiple drug resistance which was mainly due to the production of many kinds of beta-lactamases. Among the 38 strains of beta-lactamase-producing acinetobacter, those producing AmpC beta-lactamase (AmpC BLA) accounted for 42.1%.

CONCLUSIONAcinetobacter strain was one of the pathogens in burn wound infection, and its isolation and identification of its drug resistance could be beneficial to the doctors to make right choice of antibiotics.

Acinetobacter ; classification ; enzymology ; isolation & purification ; Anti-Bacterial Agents ; pharmacology ; Burn Units ; Burns ; microbiology ; Drug Resistance, Bacterial ; drug effects ; Drug Resistance, Multiple ; drug effects ; Humans ; Membrane Proteins ; metabolism ; Ribosomal Proteins ; metabolism

OBJECTIVETo characterize the genetic background of multidrug-resistant Acinetobacter baumannii (A. baumannii) from China, and the population structure of this pathogen.

METHODSA previously reported MLST scheme was applied to a collection of 33 multidrug-resistant strains of A. baumannii from China, and the data of all the strains in the A. baumannii MLST database were downloaded for the population structure analysis. The sequence types and clonal complexes were identified, the presence or absence of recombination was analyzed for each MLST locus, and the values of I(A)(S), and recombination/mutation ratio were calculated for the whole strain collection. A phylogenetic tree was constructed using all the allelic profiles in the database.

RESULTSA total of six sequence types were identified from the 33 Chinese strains tested, and 29 of these strains belonged to the CC92 clonal complex. Three (gdhB, gpi, and rpoD) of the seven MLST loci (gltA, gyrB, recA, cpn60, gdhB, gpi, rpoD) had undergone recombination with statistical evidence. For all allele profiles in the MLST database, the I(A)(S) value was 0.155 and the recombination/mutation ratio was 6.083. Sequence types from each clonal complex were grouped closely in the phylogenetic tree, which gave an overview of the microevolution of this pathogen.

CONCLUSIONThe spread of multidrug-resistant A. baumannii in China was closely related to the CC92 clonal complex. A. baumannii had an 'epidemic' population structure, i.e., a superficially clonal structure with high levels of recombination, in which successful epidemic clones arise especially including worldwide dissemination of the CC92 clonal complex to cause a widespread occurrence of multidrug-resistant infections.

Acinetobacter baumannii ; classification ; genetics ; isolation & purification ; Bacterial Typing Techniques ; China ; Cluster Analysis ; DNA, Bacterial ; genetics ; Drug Resistance, Multiple, Bacterial ; Genetic Variation ; Genetics, Population ; Molecular Epidemiology ; Molecular Sequence Data ; Multilocus Sequence Typing ; Phylogeny

BACKGROUND/AIMS: Frequent pathogens of nosocomial meningitis were investigated and the adequacy of empiric antibiotic therapy was assessed. Outcomes of nosocomial meningitis were also evaluated. METHODS: Ninety-one patients, who were diagnosed and treated for nosocomial meningitis at a single tertiary hospital in Daegu, Korea for 10 years, were included. Medical record and electronic laboratory data on the causative pathogens, antibiotics used, and outcomes were retrospectively investigated. RESULTS: Coagulase-negative Staphylococcus (40.9%) was the most common pathogen, followed by Acinetobacter (32.5%). Both were cultured as a single organism in cerebrospinal fluid (CSF). Seventy-eight patients (85.7%) had infections related to external ventricular drains (EVD). The most common empirical antibiotics were extended-spectrum beta-lactam antibiotics plus vancomycin (35/91, 38.6%). Of the 27 patients who had cultured Acinetobacter in CSF, 10 (37%) were given the wrong empirical antibiotic treatment. Seven of the 27 patients (26.9%) with cultured Acinetobacter died, and overall mortality of the 91 patients was 16.5%. In the multivariate analysis, the presence of combined septic shock (p < 0.001) and a persistent EVD state (p = 0.021) were associated with a poor prognosis. CONCLUSIONS: Acinetobacter is one of the leading pathogens of nosocomial meningitis and may lead to inadequate coverage of empiric antibiotic therapy due to increasing resistance. An EVD should be removed early in cases of suspected nosocomial meningitis, and carbapenem might be required for the poor treatment response.
Acinetobacter/classification/*isolation & purification ; Acinetobacter Infections/cerebrospinal fluid/diagnosis/*drug therapy/*microbiology ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Cerebrospinal Fluid/microbiology ; Cross Infection/cerebrospinal fluid/diagnosis/*microbiology/mortality/*therapy ; Drug Resistance, Bacterial ; Female ; Humans ; Logistic Models ; Male ; Meningitis, Bacterial/cerebrospinal fluid/diagnosis/*drug therapy/*microbiology/mortality ; Middle Aged ; Multivariate Analysis ; Odds Ratio ; Republic of Korea ; Retrospective Studies ; Risk Assessment ; Risk Factors ; Staphylococcal Infections/cerebrospinal fluid/diagnosis/*drug therapy/*microbiology/mortality ; Staphylococcus/classification/*isolation & purification ; Time Factors ; Treatment Outcome ; Young Adult

OBJECTIVETo study the epidemiology of Acinetobacter baumannii infection in patients with ventilator-associated pneumonia (VAP).

METHODSProspective clinical study was carried out with 176 episodes of VAP with etiologic diagnosis being followed in two groups.

RESULTSTwenty-six episodes were caused by Acinetobacter baumannii and one hundred-fifty episodes were caused by "other" organisms. Using logistic regression analysis, the risk of VAP due to Acinetobacter baumannii was found to be high in patients with head trauma [odds ratio (OR) = 4.20, 95% confidence interva (CI): 2.72 to 6.48], surgery (OR = 2.88, 95% CI: 1.78 to 4.66), acute respiratory dispnea syndrome (OR = 2.81, 95% CI: 1.19 to 6.64), and large-volume pulmonary aspiration (OR = 6.71, 95% CI: 3.91 to 11.50).

CONCLUSIONSAcinetobacter baumannii pulmonary infection in incubated patients had an epidemiological pattern that different from "other" organisms. Patients with high risk identified in our study might mark the existence of cross-infection during airway manipulation.

Acinetobacter ; classification ; isolation & purification ; Acinetobacter Infections ; epidemiology ; etiology ; Aged ; Aged, 80 and over ; China ; epidemiology ; Cross Infection ; epidemiology ; etiology ; Female ; Follow-Up Studies ; Humans ; Logistic Models ; Male ; Middle Aged ; Pneumonia, Bacterial ; etiology ; microbiology ; Prospective Studies ; Respiration, Artificial ; adverse effects ; Respiratory Distress Syndrome, Adult ; complications ; Risk Factors ; Time Factors ; Ventilators, Mechanical ; adverse effects

OBJECTIVETo investigate the genotype of blaADC which was a kind of AmpC produced by Acinetobacter baumannii (AB), isolated through the detection of 28 similar strains among children.

METHODS28 strains of AB were collected and isolated from the Pediatrics clinic during 2006, and were identified through bacteria and susceptibility test using Vitex-32 automicroscan GNI and GNS cards. The genotype of blaADC was confirmed by polymerase chain reaction (PCR) and them sequenced.

RESULTS3 of the 28 strains of AB showed multi-drugs resistance, with a positive rate of 10.71%. blaADC was discovered in 17 of the 28 strains and the positive rate was 60.71%. All the 28 strains of AB were resistant to Cefoxitin. blaADC positive strains were all sensitive to Ampicil/Sulbactam, and only one of them was resistant to Piperacillin/Tazobactan. There were no blaADC genes discovered in the strains that were resistant to Ampicil/Sulbactam or Piperacillin/Tazobactan. There were changes of amino acids on the site 4, 242, 342 and 376 in the sequence of blaADC of No.2 strain, comparing to gi /7258342/ emb /CAB77444. 1/ in GenBank.

CONCLUSIONAbove 60% of the AB isolated in children were carrying blaADC while a strain was collected from them at random. When they were undertaken nucleotide sequence analysis, significant difference was found from the others that landed in GenBank, which identified itself as new subtype.

Acinetobacter Infections ; microbiology ; Acinetobacter baumannii ; classification ; drug effects ; genetics ; isolation & purification ; Amino Acid Sequence ; Anti-Bacterial Agents ; pharmacology ; Bacterial Typing Techniques ; Child ; DNA, Bacterial ; genetics ; Drug Resistance, Multiple, Bacterial ; genetics ; Genotype ; Humans ; Microbial Sensitivity Tests ; Molecular Sequence Data ; Sequence Alignment ; Sequence Analysis, DNA ; beta-Lactamases ; genetics