No abstract available.
Integrons*

No abstract available.
Integrons*

BACKGROUND: Clinical isolates of AmpC beta-lactamase- producing Enterobacteriaceae were evaluated to determine the prevalence of CTX-M extended-spectrum beta-lactamases (ESBLs) and their genetic environments. METHODS: A total of 250 non-duplicate isolates of Eneterobacter aerogenes, E. cloacae, Citrobacter freundii, Serratia marcescens and Morganella morganii were collected at a Korean hospital. ESBL production was determined by double disk synergy test. For ESBL producers, bla genes were sequenced and blaCTX-M environment was characterized by PCR mapping and sequencing. RESULTS: Among the 250 isolates 29 (11.6%) produced ESBL, and 14 of the 29 isolates produced CTX-M ESBLs, including CTX-M-9 by 8 isolates, CTX-M-3 by 4 isolates, CTX-M-12 by 1 isolate, and CTX-M-14 by 1 isolate. ISEcp1 was present upstream of blaCTX-M-3, 12, and 14. Three of the four CTX- M-3 producers had the same genetic environment (pemK-ISEcp1-blaCTX-M-3-orf477-mucA). An IS903-like element was found downstream of blaCTX-M-14. ISCR1 was identified upstream of blaCTX-M-9 and ISCR1 and blaCTX-M-9 were located on sul1-type class 1 integron. The variable region between the 5'-CS and the first 3'-CS contained dfrA16 and aadA2. Its structure was similar to that of In60, but our isolates did not have IS3000 or second 3'-CS. CONCLUSION: CXT-M type ESBL was prevalent in AmpC beta-lactamase-producing Enterobacteriaceae, particularly E. cloacae. blaCTX-M genes were associated with ISEcp1 or ISCR1. This is the first report on the genetic environment of blaCTX-M in Korean isolates.
beta-Lactamases ; Citrobacter freundii ; Cloaca ; Enterobacteriaceae ; Integrons ; Korea ; Morganella morganii ; Polymerase Chain Reaction ; Prevalence ; Serratia marcescens

BACKGROUND: Metallo-beta-lactamase-mediated carbapenem resistance has been increasingly reported in Pseudomonas, Acinetobacter and other Gram-negative bacilli (GNB) in many countries. A few studies showed highly variable structure of MBL-gene cassette-carrying integrons. The aim of this study was to determine the structure of blaVIM-2-carrying integrons in Pseudomonas and Acinetobacter. METHODS: blaVIM-2-carrying GNB were isolated at a Korean hospitals during the years 1995-1999 and 2005. The size of blaVIM-2-carrying integrons was estimated by the PCR products. Representative integrons were sequenced by the dideoxy-chain termination method. The MICs of antimicrobial agents were tested by the CLSI agar dilution methods. RESULTS: During the years 1995-1999 and 2005, the approximate size of the blaVIM-2-carrying class 1 integrons was 3-7 kb in 35 Pseudomonas isolates and 3-5 kb in 24 Acinetobacter isolates. The integrons carried one-five resistance gene cassettes in addition to the blaVIM-2 cassette. Other resistance gene cassettes found were blaOXA-1, aacA1, aac(6')-I, and aac(6')-II. Interestingly, sequences homologous to part of a putative class II intron were inserted into the recombination site of the last cassette in four of nine integrons. The class 1 integron from P. aeruginosa isolates had fused orf/IntI1 in a downstream leftward inverted repeat (IRi). CONCLUSION: According to period, the size and structure of blaVIM-2-carrying integrons are quite variable, but an identical one is also present in a different genus, indicating high mobility of the blaVIM-2 cassette and horizontal transfer of the whole integron. We suggest that the class 1 integron containing the blaVIM-2 gene is spreading horizontally among Gram-negative bacilli and is undergoing continuous development in Korea.
Acinetobacter ; Agar ; Anti-Infective Agents ; Integrons ; Introns ; Korea ; Lifting ; Polymerase Chain Reaction ; Pseudomonas ; Recombination, Genetic

OBJECTIVES: Integrons are thought to play an important role in the spread of antibiotic resistance. This study investigates class 1 and 2 integron-positive methicillin-resistant coagulase-negative staphylococci strains isolated in Iran and characterizes their patterns of antimicrobial resistance. METHODS: Hundred clinical isolates of coagulase-negative staphylococci were characterized for integron content and staphylococcal cassette chromosome mec (SCCmec) type. RESULTS: Sixteen isolates carried class 1 (intI1) integrons and four isolates carried class 2 (intI2) integrons. One resistance gene array was identified among the class 1 integrons (aadA1 cassette). The distribution of SCCmec types in 50 methicillin-resistant coagulase-negative staphylococci strains showed that SCCmec types III and V dominated among the tested strains. CONCLUSION: This is the first report of methicillin-resistant coagulase-negative staphylococci strains that carry two mobile genetic elements, including class 1 and 2 integrons and SCCmec, in Iran.
Coagulase* ; Drug Resistance, Microbial ; Integrons* ; Interspersed Repetitive Sequences ; Iran ; Methicillin Resistance*

The class 1 integron and complex gene cassettes among different species of clinical isolates in northern China were characterized in this study. 383 clinical isolates were obtained from northern China, and class 1 integrons containing gene cassettes widely distributed among gram negative clinical isolates was observed. We find that the class 1 integron showed positive correlation with multidrug resistance phenotype of gram negative bacteria. In addition, we find that isolates belonged to one species harbored different types of gene cassette arrays, while same types of gene cassette arrays were observed in different species of isolates. The diversity of gene cassette arrays among the isolates indicated the complexity of multidrug resistance in clinical isolates in northern China.
Bacteria ; classification ; genetics ; isolation & purification ; China ; Hospitals, Public ; Humans ; Integrons ; genetics

Drug Resistance, Bacterial ; genetics ; Food Microbiology ; Gram-Negative Bacteria ; genetics ; isolation & purification ; Integrons ; Japan ; Seafood ; microbiology

Objective To explore the effects of Scutellaria baicalensis on activity and biofilm formation of Klebsiella pneumonia (Kp).Methods The broth and agar dilution Methods were carried out to determine minimum inhibitory concentration and minimum bactericidal concentration of Scutellaria baicalensis for TW518. VITEK-32 system was used to assay TW518 susceptibility to antibiotics. Kp biofilms were formed in vitro and stained with BacLight Live/Dead stain. The class integron geneⅠ1 mRNA expression was analyzed with RT-PCR.Results The minimum inhibitory concentration of Scutellaria baicalensis on TW518 identified as a Kp colony was 32 mg/ml, and minimum bactericidal concentration was 64 mg/ml. Scutellaria baicalensis and broad-spectrum penicillin, cephalosporin, quinolones, or beta-lactamase had synergistic bactericidal effects. Biofilm formation activity of Kp treated with Scutellaria baicalensis was significantly lower than that of the control group. And class integron geneⅠ1 mRNA expression of TW518 was significantly inhibited by Scutellaria baicalensis.Conclusions Scutellaria baicalensis has sterilization effect on Kp, and Scutellaria baicalensis could effectively inhibit Kp biofilm formation with prolonged treatment. Scutellaria baicalensis might inhibit Kp biofilm formation through down-regulating integron geneⅠ1 expression.
Biofilms ; drug effects ; Integrons ; drug effects ; Klebsiella pneumoniae ; drug effects ; physiology ; Microbial Sensitivity Tests ; Scutellaria baicalensis

Salmonella enterica isolates (n = 122), including 32 serotypes from 113 dogs and 9 cats, were obtained from household dogs (n = 250) and cats (n = 50) during 2012–2015. The isolates were characterized by serotyping, antimicrobial resistance phenotyping and genotyping, and virulence gene screening. Serovars Weltevreden (15.6%) and Typhimurium (13.9%) were the most common. The majority (43%) of the isolates were multidrug resistant. The dog isolates (12.3%) harbored class 1 integrons, of which the dfrA12-aadA2 cassette was most frequent (66.7%). The only class integron in serovar Albany was located on a conjugative plasmid. Two ESBL-producing isolates (i.e., a serovar Krefeld and a serovar Enteritridis) carried bla(TEM) and bla(CTX-M), and the bla(TEM) gene in both was horizontally transferred. Of the plasmid-mediated quinolone resistance genes tested, only qnrS (4.9%) was detected. Most Salmonella isolates harbored invA (100%), prgH (91.8%), and sipB (91%). Positive associations between resistance and virulence genes were observed for bla(PSE-1)/orgA, cmlA/spaN, tolC, and sul1/tolC (p < 0.05). The results suggest that companion dogs and cats are potential sources of S. enterica strains that carry resistance and virulence genes and that antimicrobial use in companion animals may select for the examined Salmonella virulence factors.
Animals ; Cats* ; Dogs* ; Family Characteristics ; Friends ; Humans ; Integrons ; Mass Screening ; Pets ; Plasmids ; Salmonella enterica* ; Salmonella* ; Serogroup ; Serotyping ; Virulence Factors ; Virulence*

One hundred and eight Acinetobacter baumannii strains isolated from three university hospitals in Korea were investigated for the presence of integrons and its correlation with multiple antibiotic resistance. A. baumannii strains were classified into 23 different groups based on the biochemical tests, RAPD patterns, and antibiotic susceptibility. Many strains isolated from same hospital showed identical epidemiological markers: 75% of isolates from Gwangju, 53% from Seoul, and 39% from Cheonan appeared identical. Integrase genes were detected in 79 (73%) A. baumannii isolates. The intI1 and intI2 genes were detected in 73 (68%) and 10 (9%) isolates, respectively. Class 3 integrons were not detected. Integrase genes were detected in A. baumannii isolates from Gwangju and Seoul, but not in the strains from Cheonan. Based on the epidemiological grouping, most of A. baumannii strains affecting four or more patients carried integrons, while only one strain among the sporadic strains carried a class 2 integron. Integron-carrying A. baumannii strains were resistant to more antibiotics compared to the integron-negative strains. This result suggests that integron-carrying A. baumannii strains are more apt to spread nosocomially and to show multiple antibiotic resistances.
Acinetobacter baumannii* ; Acinetobacter* ; Anti-Bacterial Agents ; Chungcheongnam-do ; Drug Resistance, Microbial ; Gwangju ; Hospitals, University ; Humans ; Integrases ; Integrons* ; Korea ; Seoul