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.

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.

Experimental Study on Tissue Fluid Influenced by Antibiotic-Acrylic Bone Cement Composite / 대한정형외과학회잡지

Failure of total joint replacement is often due to infection. Many efforts have been made to reduce the rate of infection. The use of antibiotic-acrylic bone cement composites for the preventlon and treatment of infection after joint replacement surgery has been advocated. Early reports of clinical success using bone cement containing antibiotics are encouraging, but different results of antibacterial effect of antibiotic-acrylic bone cement were reported in vitro and in vivo studies. The purpose of this experiment is to determine the effectiveness of bone cement itself on bacterial growth, stability of antibiotics in cured bone cement, and whether antibiotic acrylic bone cement composites produce an effective antimicrobial concentration in tissue fluid of hip joint and if so, the duration of it. 30 rabbits were used as test animal: 3 each for hemiarthroplasty and for hemiarthroplasty with the insertion of bone cement as control; 6 each for dicloxacillin, cephacetrile, gentamycin and amlkacin impregnated bone cements. Antibiotic activities were measured by disk diffusion method and tube dilution method using tissue fluid collected through tube inserted in the hip joint of the animals. The results were as follows: 1. Bone cement itself does not have antibacterial effec: on the growth of Staphyiococcus aureus and Escherichia coli. Antibiotic impregnated acrylic bone cements showed antibacterial effects which were stable for 3 weeks in vitro test. 2. After the insertion of antibiotic-acrylic bone cement composites, maximal concentrations of antibiotics in tissue fluid were measured at 1 hour. The concentration of antibiotics remained in tissue fluid at relatively high level for 2 days, and decreased abruptly there after. Inhibition zones in disk diffusion method could be measured until 3rd day in dicloxacillin group and 4th day in cephacetrile, gentamycin and amikacin group. No antibacterial effect could be measured in control groups. 3. On first postoperative day the concentrations of antibiotics in tissue fluid were measured as 64 mcg/ml in dicloxacillin group and 128 mcg/ml in cephacetrille, gentamycin and amikacin group. The antiblotic activities in tissue fluid could be measured for 6 days in dicloxacillin group and 7 days in cephacetrile, gentamycin and amikacin group using tube dilution method. No antibiotic activities were measured in tissue fluid of control groups. As a result of this study, it is proved that the concentration of antibiotics in tissue fluid of hip joint can be maintained above the level of minimal inhibitory concentration for about a week when antibiotic-acrylic bone cement composite is used in joint replacement arthroplasty. The impregnation of antibiotics in crylic bone cement is proved to be effective in the prevention of exogenous infection, especially in the protection of damaged tissue prone to infection postoperatively.

Studies on the Antivacterial Effect of Cephalosporin Derivatives / 대한피부과학회지

The minimal inhibitory concentration(MIC) of cephalosporin derivatives, (cephaloridine, cefazolin sodium, cephradine, cephapirin aodium, cephacetrile sodium, and cephalexin from various Korean drug companies) for Staphykcoccus aureus ATCC 25923 and Escherichia coli ATCC 25922 was measured by the tube dilution method, using Mueller-Hinton broth. The results obtained were as follows: 1) The MIC of each individual cephalosporin derivative, although produced by different manufacturers, was similiar or equal. 2) Against Staphyloeoccus aureus, cephaloridine and cephapirin had the lowest MIC while cephradine and, cephalexin the highest. Against E. coli, cephaloridine and cefazolin had the lowest MIC while cephradine and cephalexin the highest. 3) The MIC against Staphylococcus aureus was l5.6 to 250 times lower than that against E. coli in all cephalosporin derivatives. 4) The MIC against Staphylococcus aureus ranges from 0.0125 to l.0ug/ml and against E. coli from 1. 56 to 25ug/ml in all cephalasporin derivatives.