Efficient transfer of conjugative plasmids by multipoint inoculation and some observations on host range and prevalence of R plasmids

Burman, Lars; Östensson, Rune

doi:10.1016/0147-619x(78)90050-1

Cited by 4 publications

(3 citation statements)

References 16 publications

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“…Transfer of resistance. Conjugation experiments were performed at 37°C as a two-step procedure in order to enhance their efficacy (5). Conjugation mixtures were spread on agar containing ampicillin, cephalothin, cephalexin, or cefuroxime (10 g/ml) for the selection of transconjugants and rifampin (50 g/ml) for the counterselection of donors.…”

Section: Methodsmentioning

confidence: 99%

An allelic variant of the chromosomal gene for class A beta-lactamase K2, specific for Klebsiella pneumoniae, is the ancestor of SHV-1

Hæggman

Löfdahl

Burman

1997

Antimicrob Agents Chemother

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Fecal Klebsiella isolates from neonates in 22 Swedish special care units were examined by a PCR we developed for detection of the SHV-1 beta-lactamase gene. All 105 K. pneumoniae isolates and all 11 K. pneumoniae reference strains (including the K. pneumoniae subsp. pneumoniae, ozaenae, and rhinoscleromatis type strains) tested were positive, whereas all 67 K. oxytoca isolates and the K. oxytoca, K. planticola, and K. terrigena type strains tested were negative. Resistance to beta-lactams in K. pneumoniae was not transferable by conjugation, and the beta-lactamase gene was never found on a plasmid. Southern blot analysis showed that the gene had a defined chromosomal location. Isoelectric focusing and sequencing of 231-bp PCR amplicons from different isolates revealed many variants of the enzyme, with the two main groups being SHV-1 like (pI 7.6; 68 isolates) and LEN-1 like (pI 7.1; 14 isolates). Clavulanic acid markedly reduced the MICs of ampicillin for all the K. pneumoniae isolates tested. This fact, MIC profiles (penicillin rather than cephalosporin resistance), pIs, and sequence data showed that the chromosomal beta-lactamase of K. pneumoniae is a class A, group 2 enzyme distinct from the chromosomal AmpC enzymes found in several other gram-negative bacteria and from the chromosomal beta-lactamase K1 of K. oxytoca. We propose that the chromosomal beta-lactamase of K. pneumoniae be designated K2 and suggest that an allelic pI 7.6 variant of this enzyme is the ancestor of the SHV family of plasmid-mediated beta-lactamases.

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Section: Methodsmentioning

confidence: 99%

An allelic variant of the chromosomal gene for class A beta-lactamase K2, specific for Klebsiella pneumoniae, is the ancestor of SHV-1

Hæggman

Löfdahl

Burman

1997

Antimicrob Agents Chemother

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“…These plates were originally designed by G. Bertani and will be referred to as the Bertani plates. Pictures of these plates and of the multiple inoculating device have been published previously (3). The multiple inoculating device fitted either with 20-gauge pins or with 3-mm-diameter steel rods was used.…”

Section: Methodsmentioning

confidence: 99%

Incidence of lysogeny, colicinogeny, and drug resistance in enterobacteria isolated from sewage and from rectum of humans and some domesticated species

Dhillon¹,

Dhillon²

1981

Appl Environ Microbiol

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Enterobacteria were isolated by streaking swabs of sewage and rectal swabs from human volunteers and from domesticated animals. Thirty strains of human origin were identified as Escherichia coli. Out of 1,367 rectal isolates of animal origin, 21% were lysogenic (phi'), 29% were colicinogenic (col+), and 7% were col+ phi'. Out of 85 rectal samples more than 60% harbored variable numbers of col+ or phi' bacteria. Lysogens harboring homoimmune prophages were detectable in six out of eight human subjects in sequential samples taken at weekly intervals. Chickens in Hong Kong are fed on antibiotic-containing feeds; the avian isolates contained the highest frequency (98%) of drug-resistant bacteria, whereas only 39% of the bovine and 61% of the human isolates were drug resistant. Transmissible drug resistance was demonstrable in sewage isolates and those from animal sources; the highest frequency (58%) of resistance donors was shown by the avian isolates, and the lowest (9%) was shown by the bovine isolates. Unselected marker analysis has shown that a vast majority of multiply resistant donors of diverse origins are able to transmit multiple resistance.

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“…Using a multipoint needle inoculator [3] the bacteria were inoculated into a semisolid medium containing 0.3% agar (Difco), 78% (v/v) pooled urine (see above), distilled water and various supplements. coli strains to be tested were cultivated on PDM agar (9 h, 30°C) and suspended to an approximate density of 1 • 108 cells ml 1 wash solution.…”

Section: Agar Chemotaxis Assaymentioning

confidence: 99%

Chemoattracting effect of human urine on motile Escherichia coli

Herrmann

1983

FEMS Microbiology Letters

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Efficient transfer of conjugative plasmids by multipoint inoculation and some observations on host range and prevalence of R plasmids

Cited by 4 publications

References 16 publications

An allelic variant of the chromosomal gene for class A beta-lactamase K2, specific for Klebsiella pneumoniae, is the ancestor of SHV-1

An allelic variant of the chromosomal gene for class A beta-lactamase K2, specific for Klebsiella pneumoniae, is the ancestor of SHV-1

Incidence of lysogeny, colicinogeny, and drug resistance in enterobacteria isolated from sewage and from rectum of humans and some domesticated species

Chemoattracting effect of human urine on motile Escherichia coli

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