In vitro activity of six beta-lactam antibiotics against non-beta-lactamase producing and producing enterobacteria and antibiotic resistance transfer.

beta-Lactamase production was evaluated by chromogenic cephalosporin 87/312 in 184 enterobacteria isolated from clinical sources. Minimal inhibitory concentrations (MICs) of six beta-lactam antibiotics (Ampicillin, Cephaloridine, Cephalexine, Cefazoline, Cefuroxime, Cefotaxime) were determined on 90 non beta-lactamase producing and 94 beta-lactamase producing strains by a miniaturized dilution method. beta-lactamase production transfer and antibiotic resistance transfer were observed in a receiving E.

Comparative activity of ceftazidime and four other cephalosporins against gram-negative bacteria and their sensitivity to beta-lactamases.

The in vitro activity of ceftazidime compared with other beta-lactamase stable compounds was assessed against recent Gram-negative isolates. Three hundred forty-three bacterial strains were isolated from patients affected with UTI, identified by standard bacteriological methods and investigated for their production of beta-lactamases by the Nitrocefin test. MICs and MBCs (minimum inhibitory concentrations and minimum bactericidal concentration) of ceftazidime, cefamandole, cefoxitin, cefotaxime and cefuroxime were determined by a miniaturized dilution broth method against all beta-lactamase producing bacteria (129 out of 343).

Comparative in vitro activity of norfloxacin and four other chemotherapeutics against urinary gram-negative isolates.

Three hundred seventy-five Gram-negative bacterial strains were isolated from urine specimens of as many patients affected by symptomatic or asymptomatic urinary tract infections. Susceptibility of bacteria to five chemotherapeutics (norfloxacin, oxolinic acid, pipemidic acid, nalidixic acid and nitrofurantoin) was studied determining minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of each compound by a miniaturized dilution broth method. Norfloxacin, a quinoline carboxylic acid compound structurally related to nalidixic acid, showed a much higher antibacterial activity against all bacterial strains under examination including Pseudomonas sp.

[In vitro activity of beta-lactam antibiotics and their sensitivity to beta-lactamase].

beta-lactamase production was evaluated by chromogenic cephalosporin 87/312 in 116 E. coli isolated from clinical sources. Such test revealed beta-lactamase production in 54 strains out of 116 (46%): MICs of eight beta-lactam antibiotics (Ampicillin, Piperacillin, Cefazoline, Cephaloridine, Cephalexine, Cefuroxime, Cefotaxime, Cefotaxime) were determined using a miniaturized dilution broth method.

[Sensitivity of 5 beta-lactam antibiotics to beta-lactamase isolated from E. coli and its respective transconjugates].

54 beta-lactamase producing E. coli were tested to observe their eventual capacity to transfer beta-lactamase production by conjugation to a receiving E. coli K12 C600 Na-.

Rashes associated with intravenous administration of ampicillin.

532 patients under intravenous Ampicillin therapy have been included in the trial to evaluate the eventual onset of rashes. These patients have been divided into two groups: the first group comprised of patients affected with acute or chronic liver diseases, the second one with diseases of bacterial etiology. In the first group Ampicillin has been utilized either for its antiammoniaemic activity or to treat urinary or respiratory tract infections of bacterial origin.

Transferable drug resistance in Escherichia coli isolated from antibiotic-fed chickens.

The isolation and transferable drug resistance of Escherichia coli from the feces of chickens after oral administration of tetracylcine, chloramphenicol, rifampicin, and amoxicillin were studied. Each antibiotic was administered at two different dosages to four groups of 12 chickens. Treatment was carried out for 3 weeks.

[Antibiotic resistance and transfer in Enterobacteriaceae of avian origin].

Thirty-six specimens of feces were taken from as many chicken farms, from which 118 different strains of Enterobacteriaceae were isolated. The resistances of the single isolated bacteria were studied, performing plate sensitivity tests by the Kirby-Bauer method. The capacity of the bacteria under examination to transfer their antibiotic resistances in vitro to a sensitive E.