Twenty (18.5%) out of 108 clinical isolates of the family Enterobacteriaceae responsible for bloodstream infection were extended-spectrum beta-lactamase (ESBL)-positive in two screening tests, the double disk synergy test and the Oxoid Combination Disk method. Eleven out of the 20 ESBL-positive isolates transferred oxyimino-beta-lactam resistance to E. coli K12 C600 recipient strain with a frequency of 10(-8) - 10(-1) per donor cell. PCR analysis revealed that the majority of the transconjugants (9 of 11) express CTX-M-type beta-lactamases. Donor strains and their transconjugants displayed susceptibility patterns typical of ESBL producers. They were resistant to oxyimino-beta-lactams but susceptible to clavulanic acid and carbapenems. Resistances to aminoglycosides, tetracycline and mercuric chloride were, in some cases, co-transferred with oxyimino-beta-lactam resistance, suggesting that various resistance determinants were carried by the same conjugative plasmids.

• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Drug Resistance, Bacterial genetics   MeSH
• Bacteremia microbiology   MeSH
• beta-Lactamases genetics   MeSH
• beta-Lactam Resistance genetics   MeSH
• beta-Lactams pharmacology   MeSH
• Enterobacteriaceae drug effects   enzymology   genetics   isolation & purification   MeSH
• Enterobacteriaceae Infections microbiology   MeSH
• Conjugation, Genetic MeSH
• Humans MeSH
• Microbial Sensitivity Tests methods   MeSH
• Polymerase Chain Reaction MeSH
• Gene Transfer, Horizontal * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• beta-Lactamases MeSH
• beta-Lactams MeSH

Susceptibility of 62 clinical isolates of Enterobacteriaceae to 15 aminoglycosides, beta-lactams and fluoroquinolones was determined. The isolates originating from 3 intensive care units (neonatal, pediatric, and surgical) and the Department of Infant Internal Medicine of the Children's University Hospital City Center in Munich (Germany) were collected in August 1999, and March and October 2000. Transferability of antibiotic resistance from donors to their E. coli transconjugants was also demonstrated. The majority of isolates were resistant to ampicillin, cefoxitin, ceftriaxone, cefotaxime, ceftazidime and azthreonam but they were susceptible to cefepime, meropenem, aminoglycosides and fluoroquinolones. The occurrence of beta-lactamases and extended-spectrum beta-lactamases (ESBL) was also shown. In August 1999 75% of isolates produced beta-lactamases and 15% ESBL, in March 2000 95% of isolates produced beta-lactamases and 9% ESBL; in October 2000 all isolates produced beta-lactamases and only 5% produced ESBL. Plasmid DNA analysis in randomly chosen isolates and their transconjugants revealed the presence of plasmids ranging from 19 to 136 kb; in the majority of isolates a 120-kb plasmid was observed. Further analysis using restriction endonuclease suggested a dissemination and persistence of an endemic plasmid at all 4 wards of the large pediatric hospital in the City Center of Munich which may be responsible for resistance to beta-lactams among Enterobacteriaceae isolates.

• MeSH
• beta-Lactamases metabolism   MeSH
• beta-Lactam Resistance * MeSH
• Child MeSH
• Enterobacteriaceae drug effects   enzymology   genetics   MeSH
• Cross Infection microbiology   MeSH
• Conjugation, Genetic MeSH
• Humans MeSH
• Plasmids * MeSH
• Check Tag
• Child MeSH
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• beta-Lactamases MeSH

Seasonal samplings of rumen and fecal populations of Enterobacteriacae from sheep digestive tract were done to elucidate potential occurrence and spreading of antibiotic resistance in the environment. Thus 350 rumen and fecal isolates were tested for ampicillin (Amp) resistance in single sampling. Low frequency of Amp resistance (from 0 to 15%) was observed. The occurrence of tem1 encoded Amp resistance confirmed by PCR was observed among both rumen and fecal isolates. The small tem1 carrying plasmid and its transfer (mobilization) was detected and partially characterized after conjugation to laboratory Escherichia coli strain.

• MeSH
• Ampicillin pharmacology   MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Rumen microbiology   MeSH
• beta-Lactamases genetics   MeSH
• Enterobacteriaceae drug effects   isolation & purification   MeSH
• Escherichia coli genetics   MeSH
• Feces microbiology   MeSH
• Conjugation, Genetic MeSH
• Sheep microbiology   MeSH
• Gene Transfer, Horizontal MeSH
• R Factors * MeSH
• Ampicillin Resistance genetics   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Ampicillin MeSH
• Anti-Bacterial Agents MeSH
• beta-Lactamases MeSH

The prevalence of extended-spectrum beta-lactamases (ESBL) was determined among isolates of Escherichia coli (n = 63) isolated from hospitalized (43) and healthy (20) children. Ten isolates (21%) were ESBL-positive for two screening tests, the double disk-synergy test and the Oxoid Combination Disk method. One ESBL-positive isolate came from a healthy child. The transfer frequency of oxyimino-beta-lactam resistance from ESBL-producing isolates to E. coli K12 C600 recipient strain ranged from 10(-8) to 10(-5) per donor cell. Donor strains and transconjugants displayed susceptibility patterns typical of ESBL producers. They were resistant to oxyimino-beta-lactams but susceptible to clavulanic acid and carbapenems. Seven out of the 10 ESBL-positive isolates were found to produce MR/MS fimbria, which may play an important role in the colonization of the human intestinal mucosa.

• MeSH
• beta-Lactamases metabolism   MeSH
• beta-Lactam Resistance MeSH
• beta-Lactams pharmacology   MeSH
• Child MeSH
• Escherichia coli classification   enzymology   isolation & purification   MeSH
• Hospitalization * MeSH
• Escherichia coli Infections epidemiology   microbiology   MeSH
• Humans MeSH
• Microbial Sensitivity Tests MeSH
• Child, Preschool MeSH
• Diarrhea epidemiology   microbiology   MeSH
• Intestinal Mucosa microbiology   MeSH
• Check Tag
• Child MeSH
• Humans MeSH
• Child, Preschool MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• beta-Lactamases MeSH
• beta-Lactams MeSH