[Antimicrobial sensitivity of coagulase-positive staphylococcal strains isolated from bovine mastitis in the central dairy catchment area of Argentina ]. / Susceptibilidad a antimicrobianos de cepas de estafilococos coagulasa positivos aisladas de mastitis bovina en la cuenca lechera central de la Argentina.

The activity of antimicrobial agents frequently used for treating bovine mastitis was determined against 101 coagulase-positive staphylococci isolated from bovine mammary secretion. The isolates were obtained from 39 dairy farms located in the central dairy area of Argentina. The disk diffusion method was used and the following antimicrobial agents were tested: penicillin, ampicillin, oxacillin, cephacetrile, penicillin + novobiocin, erythromycin, pirlimycin, novobiocin and neomycin. The highest levels of resistance were observed against penicillin and ampicillin (47.6%), while the lowest against erythromycin (2%), pirlimycin (4%) and neomycin (2.9%). No resistant strains against oxacillin, cephacetrile and penicillin + novobiocin were detected.

Susceptibilidad a antimicrobianos de cepas de estafilococos coagulasa positivos aisladas de mastitis bovina en la cuenca lechera central de la Argentina / Antimicrobial sensitivity of coagulase-positive staphylococcal strains isolated from bovine mastitis in the central dairy catchment area of Argentina

The activity of antimicrobial agents frequently used for treating bovine mastitis was determined against 101 coagulase-positive staphylococci isolated from bovine mammary secretion. The isolates were obtained from 39 dairy farms located in the central dairy area of Argentina. The disk diffusion method was used and the following antimicrobial agents were tested: penicillin, ampicillin, oxacillin, cephacetrile, penicillin + novobiocin, erythromycin, pirlimycin, novobiocin and neomycin. The highest levels of resistance were observed against penicillin and ampicillin (47.6), while the lowest against erythromycin (2), pirlimycin (4) and neomycin (2.9). No resistant strains against oxacillin, cephacetrile and penicillin + novobiocin were detected.

Susceptibilidad a antimicrobianos de cepas de estafilococos coagulasa positivos aisladas de mastitis bovina en la cuenca lechera central de la Argentina / Antimicrobial sensitivity of coagulase-positive staphylococcal strains isolated from bovine mastitis in the central dairy catchment area of Argentina

The activity of antimicrobial agents frequently used for treating bovine mastitis was determined against 101 coagulase-positive staphylococci isolated from bovine mammary secretion. The isolates were obtained from 39 dairy farms located in the central dairy area of Argentina. The disk diffusion method was used and the following antimicrobial agents were tested: penicillin, ampicillin, oxacillin, cephacetrile, penicillin + novobiocin, erythromycin, pirlimycin, novobiocin and neomycin. The highest levels of resistance were observed against penicillin and ampicillin (47.6), while the lowest against erythromycin (2), pirlimycin (4) and neomycin (2.9). No resistant strains against oxacillin, cephacetrile and penicillin + novobiocin were detected.(AU)

[Effects of various antibiotic treatments of lactating cows with subclinical mastitis]. / Uber den Erfolg verschiedener antibiotischer Therapieformen bei laktierenden Kühen mit subklinischer Mastitis.

101 cows with 197 udder quarters with subclinical mastitis from 23 dairy farms were selected for different antibiotic treatments under field conditions. Group 1 consisting of 27 animals and 50 infected udder quarters was treated twice intramammaryly with 250 mg Cefacetril. Group 2 (26 animals/50 quarters) was treated twice intramuscular with 10 Mio IU Penethamathydrojodid and with 5 Mio IU respectively. Group 3 was treated twice with the combination of the intramammary and the intramuscular therapies in the above mentioned groups. Group 4 served as control. 23 animals with 36 subclinical infected udder quarters were treated twice intramuscular with 2.0 ml of sterile isotonic sodium-solution. Therapeutic success was controlled with bacteriological and cytological examinations of quarter milk probes one week, two weeks and four weeks after the end of treatments. Concerning bacteriological healing both the intramammary and the combined therapy had an even success with a 72.9% elimination rate of pathogenic bacteria whereas the intramuscular therapy led to bacteriological healing in 36.7%. In comparison cytological healing rates (< 100 x 10(3) cell counts per ml milk) with 29.8% in group 1, 32.3% in group 3 and 8.2% in group 2 were not satisfying. S. aureus was the predominating isolated bacteria. With respect to bacterial species found in the subclinically infected milk probes, elimination rates in Streptococcaceae and in Enterococcaceae was evident higher than in Staphylococcaceae. The results are discussed.

The cephalosporin antibiotics in pediatric therapy.

The cephalosporins have been available for clinical use for nearly 20 years and a large number is presently marketed, including drugs with a wide range of different pharmacokinetic and microbiologic properties. While some of these agents have certain specific uses in which they excel, the cephalosporins have not replaced older antibiotics but do provide the physician with a broader range of choices for the treatment of many infections, allowing greater individualization of therapy.

Effects of cephacetrile on reproduction cycle.

The research of possible effects of cephacetrile (Celospor) on the reproductive function was carried out on two animal species, rats and rabbits. The animals were divided into experimental groups, each treated subcutaneously with different amounts of cephacetrile (50, 100 and 500 mg/kg/die), control group receiving physiological solution. Effects of the preparation on fertility and post-natal growth in rats were analyzed, and trials were performed to test perinatal toxicity and teratogenesis in rabbits. From the observation of the experimental data collected it can be assumed that cephacetrile, administered subcutaneously in the given doses--1, 2 and 10 times, respectively, higher than the maximum therapeutic dose advisable--does not alter fertility, gestation and post-natal development of term foetuses of rats and fertility and gestation of rabbits.

Bactericidal activity and induction of cell volume alterations of cephalosporins in Escherichia coli.

The bactericidal efficacy of cefuroxime and cephacetril on Escherichia coli cultures was measured by killing curves. Simultaneously bacterial cell volumes were analysed by electronic particle counting using a Coulter Counter Channelanalyser system in order to study the relationship between bactericidal activity and bacterial cell volume alterations. Various concentrations (2-120 mg/l cefuroxime and 16-120 mg/l cephacetril) and different exposure times (over a time period of 12 h) were used. Growth medium was human plasma ultrafiltrate. The bactericidal activity of cefuroxime, as measured by the rate of killing of the E. coli culture, was independent of the concentration and constant in the range 4-120 mg/l. The characteristic cefuroxime-induced change in bacterial cell volume was a marked volume increase up to a maximum of 5-fold after 160-200 min exposure with a low-grade bacteriolysis following. The cefuroxime-induced bacterial volume changes were, in accordance with the bactericidal testing, almost independent of the concentration. In contrast, the killing curves for cephacetril strongly depended on the drug concentration. However, this effect was short-lived and regrowth of the E. coli culture followed. The typical cephacetril-induced volume distribution curves were also highly concentration-dependent. With increasing drug levels bacterial cell volume increased up to 20-fold, and regrowth of a persisting bacterial population occurred at lower antibiotic concentrations. Bacteriolysis started earlier than with cefuroxime. The relationship between loss of viability and cell volume increase was more marked with cefuroxime than with cephacetril.

Encapsulated forms of slow-release dry cow products of rapidly absorbed antibiotics.

The persistence of chloramphenicol, cephacetrile, and clindamycin in the udders of dry cows was studied after drying-off therapy with salts of these antibiotics suspended in conventional oil bases. Antibiotic activity was not found in dry udder secretions collected 3-5 days after treatment. After equivalent doses of encapsulated formulations of chloramphenicol were suspended in the same oil bases and infused at drying-off, most of the drug remained bound within the microcapsules; chloramphenicol concentrations higher than 10 micrograms/ml secretion were maintained for 3-4 weeks, but upon release from the microcapsule, the free drug was very quickly absorbed from the udder. Microcapsulated formulations of cephacetrile and clindamycin were infused at drying-off, suspended in the same type of oil base and at similar doses to the non-capsulated preparations. The concentrations of free drug in the secretions remained constant over a period of 2-3 weeks, although total drug (bound and free) concentrations in the udder, which were much higher than free drug levels, were progressively and markedly reduced. It appeared that after infusion of the microcapsulated preparations of cephacetrile and clindamycin, rates of drug release from the depot were equal to the rates of absorption of free drug from the udder.

[Cefacetril in treatment of clinical bovine mastitis]. / Lekuvane na klinichni mastiti pri kravite s cefacetril.

The dynamic of the reconvalescence process was followed up in the udder of cows treated with the intramammary preparation Cefacetril. Complete therapeutic effect was recorded with 93.10 per cent of the cases, elimination of the infection -- with 86 per cent, and normalization of the cell content -- with 37.93 per cent. It was also established that during recovery the chlorine content of milk dropped, while lactose rose. The percent content of the protein fractions changed, whereupon the serum albumin and the immunoglobulins decreased, and the beta-lactoglobulin and the gamma-lactoglobulin increased.

Permeability of Pseudomonas aeruginosa outer membrane to hydrophilic solutes.

Pseudomonas aeruginosa is usually resistant to a wide variety of antibacterial agents, and it has been inferred, on the basis of indirect evidence, that this was due to the low permeability of its outer membrane. We determined the permeability of P. aeruginosa outer membrane directly, by measuring the rates of hydrolysis of cephacetrile, cephaloridine, and various phosphate esters by hydrolytic enzymes located in the periplasm. The permeability to these compounds was about 100-fold lower than in the outer membrane of Escherichia coli K-12. Also, we found that the apparent Km values for active transport of various carbon and energy source compounds were typically higher than 20 microM in P. aeruginosa, in contrast to E. coli in which the values are usually lower than 5 microM. These results also are consistent with the notion that the P. aeruginosa outer membrane indeed has a low permeability to most hydrophilic compounds and that this membrane acts as a rate limiting step in active transport processes with high Vmax values.

In vitro evaluation of pyridine-2-azo-p-dimethylaniline cephalosporin, a new diagnostic chromogenic reagent, and comparison with nitrocefin, cephacetrile, and other beta-lactam compounds.

Pyridine-2-azo-p-dimethylanaline cephalosporin (PADAC), a chromogenic reagent which is purple and changes to yellow upon cleavage of its beta-lactam ring, was evaluated in comparison with other chromogenic cephalosporins. PADAC exhibited little antimicrobial activity against gram-negative bacteria, but did have good activity (minimum inhibitory concentration, 0.12 to 0.5 microgram/ml) against Staphylococcus aureus, a quality comparable to nitrocefin. Nitrocefin, however, demonstrated an unexpected and uniquely potent activity against Streptococcus faecalis (minimum inhibitory concentration, less than or equal to 0.06 to 0.12 microgram/ml) The relative hydrolysis rate of PADAC when subjected to six different beta-lactamases was substantially greater than that of cephacetrile, but less than that of nitrocefin. The relative hydrolysis rates of PADAC and nitrocefin were comparable with type IIIa beta lactamase and the derived from Bacillus cereus. The inhibition of beta-lactamase hydrolysis of the chromogenic cephalosporin substrates by six enzyme-stable inhibitors was generally greater with PADAC than with nitrocefin. Unlike nitrocefin, PADAC mixed with 50% human serum or various broth culture media showed no evidence of color change or degradation over several hours. The subsequent enzyme hydrolysis rates of such mixtures were the same as in phosphate buffer. Beta-lactamase-containing bacterial suspensions and clinical specimens containing such bacteria produced positive visual and spectrophotometric color changes when mixed with PADAC or nitrocefin. Although color changes occurred more slowly with PADAC than with nitrocefin, PADAC was not adversely influenced (non-enzyme-related color change) by the protein content of specimens. PADAC appears to be a promising alternative for beta-lactamase diagnostic testing in the clinical and research microbiology laboratory.

[Microbiological evaluation of the antibacterial activity of cefotaxime in comparison with other cephalosporins]. / Valutazione microbiologica dell'attività antibatterica del cefotaxime in rapporto ad altre cefalosporine.

In this study we have evaluated the antibacterial activity of six cephalosporins of the first generation (cephacetrile, cephalothin, cefazolin, cephaloridin, cephalexin, cephradine) two cephalosporin of the second generation (cefoxitin and cefuroxime) and two of the third generation (cefotaxime and cefoperazone) against 66 clinical bacterial isolates. Cefotaxime has been highly active against the strains examined in this study with low MICs.

A Study on The Antibacterial Effect of antibiotic Impregnated Bone Cement / 대한정형외과학회잡지

This experiment was performed to determine the stability of antiblotics in cured bone cement and the antibacterial effect with various the amount of antibiotics mixed in bone cement. Experimental animals were divided into control and antibioticimpregnated groups; 3 each for control, cloxacillin, celospor, kanamycln and panimycln groups. Antibiotic activities were measured by disk diffusion method using Staphylococcus aureus and Escherichla coli as standard organisms. The results were as follows: 1. Bone cement itself does not have antibacterial effect on the growth of Staphylococcus aureus and Escherlchia coli. Antlbiotlc impregnated acrylic bone cement showed antibacterial effects which was stable for 4 weeks. 2. In vitro test, the amount to antibiotics released In 24 hours perlod was proportional to the amount of antibiotlcs mixed in bone cement. 3. The duration of antibacterial effect was also roughly proportional to the amount of antiblotics mixed In bone cement. 4. No antibacterial effect could be measured in control groups. 4. In vivo test, the result was revealed similar patterns compared with the result of “In vitro test”, but the amounts of antibiotics released and durations of antibaterial effect was decreased. No antibacterial effect could be measured in control groups. As a result of this sutdy of this study, It is proved that the amount of antiblotics and the duratlon of antibacterial effect are proportional to the amount of antibiotics mixed in bone cemcnt. The impregnation of antiblotics in acrylic bone cement may be used to prevent and treat Infection in the orthopedic fleld.

The cephalosporins: activity and clinical use.

The cephalosporin antibiotics have been employed with increasing frequency since their introduction into clinical practice in the early 1960s. With the exception of cephaloridine, cephalosporin compounds are not associated with the production of significant untoward effects. The availability of newer cephalosporins, both oral and parenteral, with enhanced antibacterial activity, has expanded the clinical indications for administration of these antibiotics.

[Antibiotic concentration during extracorporeal circulation (author's transl)].

In open surgery, ampicillin (Solcillin) or cephacetrile (Celtol), 2 g for patients weighing 20 kg or more, and 1 g for those below 20 kg, was administered, and the antibiotic concentrations in blood and urine were estimated during extracorporeal circulation, from the time of operation to the admission in an intensive care unit (Group A). In other group, a total circulation volume of 0.3 mg/ml of the antibiotic was administered, based on body weight of patients and priming volumes (Group B). In Group A, blood concentration of antibiotics was so variable that it was difficult to decide additional dosage. In Group B, comparatively definite concentrations were estimated in each case. In extracorporeal circulation for a long time, it is preferable to maintain the blood concentration of antibiotic at 50 micrograms/ml, by additional antibiotic administration 90 approximately 120 minutes after the beginning of the extracorporeal circulation. In patients with preoperative subacute bacterial endocarditis, the blood concentration should be kept over 100 micrograms/ml during extracorporeal circulation.