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At least 487 records · Page 27Linked to original sources
PubMed1999

Identification of Enterobacteriaceae by partial sequencing of the gene encoding translation initiation factor 2.

Nucleotide sequence analysis is increasingly being used to identify bacteria. In this work, a PCR assay based on degenerate primers was used to obtain the partial sequence of infB, the gene encoding translation initiation factor 2 (IF2), in 39 clinical isolates of different Enterobacteriaceae. The partial sequence encodes the GTP-binding domain of IF2. Together with sequences from the literature, a total of 15 species, each represented by one to seven strains, was investigated. Phylogenetic analysis yielded an evolutionary tree which had a topology similar to a tree constructed using available 16S rRNA sequences. It is concluded that the inter-species variation of the infB gene fragment is sufficient for its use in the characterization of strains that have aberrant phenotypic reactions.

Bacterial Typing Techniques↗
PubMed2004

Prevalence of colonisation with third-generation cephalosporin-resistant Enterobacteriaceae in ICU patients of Heidelberg University Hospitals.

The aim of this study was to assess colonisation and transmission of third-generation cephalosporin-resistant Enterobacteriaceae (CRE) from patients in 16 intensive care units. A prospective, repetitive point prevalence survey was performed over 6 months, involving samples from 1851 patients. CRE were isolated from 186 (10%) patients, with Enterobacter spp. being the most common. Mean point prevalence rates were significantly higher for paediatric wards (22.5%) compared to surgical (8.1%) and medical (5.5%) units. All CRE isolates were typed by pulsed-field gel electrophoresis. Non-outbreak nosocomial transmission rates of these pathogens were calculated as 12.8% for paediatric patients, compared to 6.8% for adult patients, which may reflect differences in sensitivity to overgrowth with resistant bacteria and contact with health care workers.

Adolescent↗
PubMed2004

Evolution of acquired resistance to third-generation cephalosporins in Enterobacteriaceae in a Tunisian hospital 1993-2001.

Between January 1993 and December 2001, the overall frequency of resistance to third-generation cephalosporins in isolates of Enterobacteriaceae from Charles Nicolle Hospital, Tunis, rose from 2.4% to 7.4%. Klebsiella pneumoniae was the most prevalent species (56%), followed by Escherichia coli (15%) and Proteus mirabilis (9%). A rate of 49% was observed among isolates from paediatric patients in 1999, caused mostly by outbreaks in the neonatal intensive care unit of K. pneumoniae and P. mirabilis isolates that produced extended-spectrum beta-lactamases.

Anti-Bacterial Agents↗
PubMed1976

Rapid diagnosis of Enterobacteriaceae. I. Detection of bacterial glycosidases.

The paper describes a number of tests for the rapid detection of glycosidases including alpha-glucosidase, beta-glucosidase, beta-glucuronidase, beta-xylosidase and alpha-fucosidase. The methods use heavy suspensions of viable but non-multiplying bacteria in a buffered solution of a chromogenic substrate. The results of the tests are readable within 4 h. The application of these tests to a collection of 633 strains of Enterobacteriaceae and Vibrionaceae demonstrates that some of the tests may be valuable additions to the present tests available for the identification of bacteria belonging to these families. beta-glucuronidase activity was observed only in strains of the Escherichia-Shigella group. 97 per cent of the Escherichia strains possessed beta-glucuronidase activity. beta-xylosidase activity was almost completely restricted to strains of the Klebsiella-Enterobacter group in addition to Yersinia strains. None of the strains possessed alpha-fucosidase activity.

Bacteriological Techniques↗
PubMed1997

Antibiotic susceptibility of blood culture isolates of Enterobacteriaceae from six Norwegian hospitals 1991-1992.

From August 1991 to February 1992, each of the six largest hospitals throughout Norway collected 84 to 107 consecutive blood culture isolates of Enterobacteriaceae, altogether 571 isolates. The distribution of various species and genera at the different hospitals was uniform; Escherichia coli being most prevalent (57-67%), followed by Klebsiella spp. (12-18%) and Proteus mirabilis (7-11%). Twenty-one and 4% of E. coli isolates were resistant to ampicillin and cefuroxime, respectively, and 11% of Klebsiella isolates were cefuroxime resistant. Five Enterobacter isolates and one Citrobacter isolate were resistant to ceftazidime, and one Salmonella isolate was resistant to imipenem. All isolates were susceptible to ciprofloxacin and tobramycin. These results were compared with the antibiotic consumption in each hospital region. Although hospitals in the regions with the highest consumption of ampicillin tended to have a higher percentage of isolates resistant to this agent, no significant differences were found. There was no significant difference between hospitals regarding prevalence of cefuroxime-resistant isolates.

Anti-Bacterial Agents↗
PubMed2006

Genetic environment of acquired bla(ACC-1) beta-lactamase gene in Enterobacteriaceae isolates.

We studied the genetic organization of bla(ACC-1) in 14 isolates of Enterobacteriaceae from France, Tunisia, and Germany. In a common ancestor, ISEcp1 was likely involved in the mobilization of this gene from the Hafnia alvei chromosome to a plasmid. Other genetic events involving insertion sequences (particularly IS26), transposons (particularly Tn1696), or sulI-type integrons have occurred, leading to complex genetic environments.

Base Sequence↗
PubMed2006

qnr prevalence in ceftazidime-resistant Enterobacteriaceae isolates from the United States.

We screened 313 ceftazidime-resistant Enterobacteriaceae isolates obtained in the United States from 1999 to 2004 for all three known qnr genes. A qnr gene was present in 20% of Klebsiella pneumoniae isolates, 31% of Enterobacter sp. isolates, and 4% of Escherichia coli isolates. qnrA and qnrB occurred with equivalent frequencies and, except for qnrB in enterobacters, were stable over time. qnrS was absent.

Age Distribution↗
PubMed1977

Synergy between ticarcillin and tobramycin against Pseudomonas aeruginosa and Enterobacteriaceae in vitro and in vivo.

The antibacterial activities of ticarcillin, carbenicillin, tobramycin, and gentamicin and of combinations of these antibiotics were measured against Pseudomonas aeruginosa and other gram-negative bacilli in vitro and in experimental mouse infections. Synergistic effects were produced by the penicillin/aminoglycoside combinations in growth inhibition tests and in bactericidal tests against many of the bacteria tested. Combinations of ticarcillin + tobramycin were more active in vitro than carbenicillin + gentamicin against P. aeruginosa but were no more active than the latter against other gram-negative bacilli. Ticarcillin + tobramycin and carbenicillin + gentamicin also demonstrated synergistic activities against P. aeruginosa, Escherichia coli, and Enterobacter cloacae in experimental mouse infection models. Thus, the penicillin/aminoglycoside combinations produced greater protective effects than the individual antibiotics against lethal intraperitoneal infections and also were more effective in reducing kidney counts of viable bacteria and kidney abscess formation in experimental pyelonephritis infections. As was the case in vitro, ticarcillin + tobramycin was more effective than carbenicillin + gentamicin against the experimental P. aeruginosa infections. The results of these in vitro and in vivo studies suggest that combined therapy with ticarcillin and tobramycin may be warranted in the treatment of serious infections due to P. aeruginosa and Enterobacteriaceae.

Animals↗
PubMed1982

Antimicrobial activity of amikacin combinations against Enterobacteriaceae moderately susceptible to third-generation cephalosporins.

Enterobacteriaceae strains having elevated minimal inhibitory concentrations (greater than or equal to 2.0 to less than or equal to 32 micrograms/ml) of cefoperazone, cefotaxime, ceftazidime, and moxalactam were synergistically inhibited by amikacin combinations (54.1 to 69.6% occurrence). Indifference was rare (8.1% for moxalactam), and true antagonistic interactions were not observed. Strains resistant or susceptible to these new cephalosporins were also synergistically inhibited by the addition of amikacin, reducing resistant cephalosporin minimal inhibitory concentrations to clinically achievable levels.

Amikacin↗
PubMed1986

Transfer of amikacin resistance by closely related plasmids in members of the family Enterobacteriaceae isolated in Chile.

During a 9-month period when amikacin was the sole aminoglycoside used clinically in a hospital in Santiago, Chile, resistance to amikacin and other antibiotics was encountered in 42 strains of the family Enterobacteriaceae, including Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Enterobacter cloacae, Serratia marcescens, and Serratia liquefaciens. Amikacin resistance was transferable by conjugation and carried by IncM plasmids ranging in size from ca. 48.4 to 58.1 kilobase pairs. The plasmids had ca. 70 to 80% of their structure in common, as judged after digestion with restriction endonucleases. The resistance was mediated by a 6' aminoglycoside acetyltransferase. We conclude that selective pressure has favored the dissemination of a wide-host-range amikacin resistance plasmid and its derivatives.

Amikacin↗
PubMed1986

Epidemiology of intestinal colonization by members of the family Enterobacteriaceae highly resistant to erythromycin in a hematology-oncology unit.

Intestinal colonization by highly erythromycin-resistant members of the family Enterobacteriaceae was surveyed for 4 years in a hematology-oncology unit. Fifty-four of 555 patients (9.7%) were colonized, each with a different strain. The incidence of intestinal carriage was not correlated with erythromycin consumption in the ward but was strongly associated with individual exposure to erythromycin.

Carrier State↗
PubMed1986

Epidemiology of intestinal colonization by members of the family Enterobacteriaceae resistant to cefotaxime in a hematology-oncology unit.

Intestinal colonization by members of the family Enterobacteriaceae resistant to cefotaxime was surveyed for 3 years in a hematology-oncology unit. Of 416 patients, 66 (15.9%) were colonized, each with a different strain. The incidence of intestinal carriage was not correlated with cefotaxime consumption in the ward but was strongly associated with individual exposure to cefotaxime.

Agranulocytosis↗
PubMed1989

Nucleotide sequence of the aacC2 gene, a gentamicin resistance determinant involved in a hospital epidemic of multiply resistant members of the family Enterobacteriaceae.

A gentamicin resistance determinant of a conjugative plasmid from Enterobacter cloacae was cloned on a 3.2-kilobase fragment in the PstI site of pBR322. Substrate profiles for eight aminoglycosides at three concentrations showed that the resistance was due to aminoglycoside-(3)-N-acetyltransferase isoenzyme II. Insertion mapping by the gamma-delta transposon revealed that the size of the gene was approximately 1 kilobase. Nucleotide sequencing of the aacC2 gene identified an open reading frame of 858 base pairs, preceded by a promoter and a ribosome-binding site. From these data the molecular mass of the protein was calculated to be 30.6 kilodaltons. A comparison of the nucleotide sequence of the aacC2 gene with those published for the aacC3 and aacC4 genes showed complete homology of the aacC2 gene and the presumed aacC3 gene. An internal restriction fragment of the gene used as a probe in colony hybridization demonstrated the presence of the aacC2 gene in 86% of 86 multiply resistant isolates of the family Enterobacteriaceae obtained during an 18-month hospital epidemic. This corroborates our earlier data on the enzyme identification by the susceptibility profiling method.

Autoradiography↗
PubMed1998

Cefotaxime-resistant Enterobacteriaceae isolates from a hospital in Warsaw, Poland: identification of a new CTX-M-3 cefotaxime-hydrolyzing beta-lactamase that is closely related to the CTX-M-1/MEN-1 enzyme.

A group of cefotaxime-resistant Citrobacter freundii and Escherichia coli isolates were collected by a clinical laboratory in a hospital in Warsaw, Poland, in July 1996. Detailed analysis has shown that all of these produced a beta-lactamase (pI, 8.4) belonging to the CTX-M family, one of the minor extended-spectrum beta-lactamase families with a strong cefotaxime-hydrolyzing activity. Sequencing has revealed that C. freundii isolates produced a new CTX-M-3 enzyme which is very closely related to the CTX-M-1/MEN-1 beta-lactamase, sporadically identified in Europe over a period of 6 years. Amino acid sequences of these two beta-lactamases differ at four positions: Val77Ala, Asp114Asn, Ser140Ala, and Asn288Asp (the first amino acid of each pair refers to CTX-M-1/MEN-1 and second refers to CTX-M-3). The partial sequence of the E. coli CTX-M gene was identical to the corresponding region of bla(CTX-M-3), but a transconjugant of the E. coli isolate expressed higher levels of resistance to beta-lactams than did C. freundii transconjugants. These resistance differences correlated with differences in plasmid DNA restriction patterns. Our results suggest that CTX-M genes have been spread among different species of the family Enterobacteriaceae in the hospital and that the CTX-M-3-expressing C. freundii strain causing routine urinary tract infections has been maintained for a relatively long time in the hospital environment.

Amino Acid Sequence↗
PubMed2001

Rapid screening technique for class 1 integrons in Enterobacteriaceae and nonfermenting gram-negative bacteria and its use in molecular epidemiology.

A screening technique for integrons in members of the family Enterobacteriaceae and nonfermenting gram-negative bacteria by real-time PCR is reported. A total of 226 isolates of gram-negative bacteria obtained from a variety of clinical specimens were screened for class 1 integrons by real-time PCR performed on a LightCycler instrument. This technique used a primer pair specific for a 300-bp conserved region at the 5' ends of class 1 integrons. The screening assay was evaluated by comparison with results obtained by the conventional, thermal-block PCR (long PCR) by using established conditions and primers for the detection of class 1 integrons, and the real-time PCR technique was thus shown to be both sensitive and specific. DNA from 50 of 226 (22%) isolates screened was identified as containing an integron by the screening PCR, and sequence data were obtained across the integron for 34 of 50 (68%) of these isolates. In an attempt to study the molecular epidemiology of antimicrobial resistance genes carried within integrons, a comparison of the types of gene cassettes carried by isolates from different patients was made. Adenyltransferase genes conferring resistance to streptomycin and spectinomycin were the predominant gene cassettes amplified in the study. Resistance to trimethoprim was also frequently found to be encoded within integrons. Furthermore, multiple bacterial isolates obtained from one patient over a 5-month period were all shown to carry an integron containing the same single adenyltransferase gene cassette, suggesting that these elements were relatively stable in this case.

Community-Acquired Infections↗
PubMed2003

Survey of plasmid-associated genetic markers in enterobacteriaceae with reduced susceptibilities to cephalosporins.

Clinical isolates of Enterobacteriaceae with reduced susceptibilities to cephalosporins were collected from 1993 to 2000. The organisms were screened for the extended-spectrum beta-lactamase (ESBL) phenotype, and plasmid extracts were screened for genetic markers by hybridization. A bla(TEM) probe was derived from pUC19; other probes were derived from pACM1, the plasmid responsible for the first known appearance of an ESBL in our institution. These probes included bla(SHV), int, aac(3)-Ia, dfrA1, IS6100, tetA, IncM markers, and Anon 13, a marker for the Klebsiella pneumoniae chromosomal sequences that flank bla(SHV-5). There were 42 hybridization patterns among 237 isolates. Patterns designated pACM1-like occurred in 44% of the isolates (eight species) and were always associated with the clavulanic acid (CA)-susceptible ESBL phenotype. The TEM marker was not predictive of the ESBL phenotype. Mapping indicated the presence of an SHV marker and up to 7.5 kb of its flanking chromosomal sequences in three non-IncM plasmids obtained in transformation experiments. We theorize that this DNA segment spread to other plasmids from pACM1-like sources. CA insensitivity became more frequent with time and was usually associated with either the TEM marker or the absence of both bla markers. One plasmid-encoded enzyme with characteristics of an AmpC beta-lactamase was observed in a transformant lacking both TEM and SHV markers. Although SHV type ESBLs were a continuing source of reduced susceptibility to cephalosporins in our institution, organisms with different resistance mechanisms were added to the hospital microflora in later years. These changes might be related, in part, to ESBL control strategies implemented in 1995.

Adult↗
PubMed2004

Dissemination of CTX-M-type beta-lactamases among clinical isolates of Enterobacteriaceae in Paris, France.

We analyzed 19 clinical isolates of the family Enterobacteriaceae (16 Escherichia coli isolates and 3 Klebsiella pneumoniae isolates) collected from four different hospitals in Paris, France, from 2000 to 2002. These strains had a particular extended-spectrum cephalosporin resistance profile characterized by a higher level of resistance to cefotaxime and aztreonam than to ceftazidime. The bla(CTX-M) genes encoding these beta-lactamases were involved in this resistance, with a predominance of bla(CTX-M-15). Ten of the 19 isolates produced both TEM-1- and CTX-M-type enzymes. One strain (E. coli TN13) expressed CMY-2, TEM-1, and CTX-M-14. bla(CTX-M) genes were found on large plasmids. In 15 cases the same insertion sequence, ISEcp1, was located upstream of the 5' end of the bla(CTX-M) gene. In one case we identified an insertion sequence designated IS26. Examination of the other three bla(CTX-M) genes by cloning, sequencing, and PCR analysis revealed the presence of a complex sul1-type integron that includes open reading frame ORF513, which carries the bla gene and the surrounding DNA. Five isolates had the same plasmid DNA fingerprint, suggesting clonal dissemination of CTX-M-15-producing strains in the Paris area.

DNA Fingerprinting↗
PubMed2005

CTX-M-10 linked to a phage-related element is widely disseminated among Enterobacteriaceae in a Spanish hospital.

CTX-M-10 has been widely disseminated among multiple clones of several species of Enterobacteriaceae, harboring seemingly different plasmids, for over a decade in Ramón y Cajal University Hospital, Madrid, Spain. Cloning and sequencing of a 12.2-kb DNA fragment from plasmid pRYCE21 from Klebsiella pneumoniae strain KP4aC revealed a novel phage-related element immediately upstream of bla(CTX-M-10) conserved among different CTX-M-10-producing strains. This is the first report showing an extended-spectrum-beta-lactamase gene linked to a phage-related element.

Amino Acid Sequence↗