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1.
Abstract

An in vitro susceptibility assay of sarafloxacin (A-56620), a new 4-quinolone, was performed against five important bacterial species that are pathogenic to fish. A collection of 44 clinical isolates and five corresponding type strains were included in the study. The objectives were to determine the minimal inhibitory concentrations (MICs) of sarafloxacin by a drug microdilution method and to compare the MIC values at two different temperatures, 4 and 15°C. Sarafloxacin was active against all species tested and showed the following mean MIC values at 15 and 4°C, respectively, against the bacterial pathogens investigated: Aeromonas salmonicida subspecies salmonicida, 0.029 and 0.045 μg/mL; atypical A. salmonicida, 0.053 and 0.041 μg/mL; Vibrio anguillarum, 0.085 and 0.054 μg/mL; V. salmonicida, 0.125 and 0.123 μg/mL; and Yersinia ruckeri, 0.023 and 0.031 μg/mL. The MICs ranged from 0.0025 μg/mL (or less) for two strains of A. salmonicida salmonicida to 0.32 μg/mL for one strain of atypical A. salmonicida and one strain of V anguillarum. A decrease in antimicrobial activity was observed as the incubation temperature was lowered from 15 to 4°C; however, no significant statistical difference between the measured values was demonstrated.  相似文献   

2.
The prevalence of strains of Staphylococcus aureus, coagulase‐negative (CN) staphylococci, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, E. faecium and Bacillus cereus, was investigated in 111 bulk milk samples. Staphylococcus aureus was isolated from 38 samples, CN staphylococci from 63 samples, E. coli from 49 samples, E. faecalis or E. faecium from 107 samples, and L. monocytogenes from two samples. Bacillus cereus was not found in any of the samples and three samples were free of any of the selected species. Sensitivity to the anti‐microbial drugs amikacin, ampicillin, ampicillin + sulbactam, cephalothin (CLT), cephotaxime, clindamycin, chloramphenicol (CMP), co‐trimoxazole, erythromycin (ERY), gentamicin, neomycin, norfloxacin, oxacillin, penicillin, streptomycin (STR), tetracycline (TTC) and vancomycin was tested using the standard dilution technique. Minimum inhibitory concentration (MIC) characteristics (MIC50, MIC90, MIC range) were determined for each microbial species. Resistance against one or more anti‐microbial drugs was found in 93% of S. aureus, 40% of CN staphylococci, 73% of E. coli, 88% of E. faecalis, 55% of E. faecium, and one L. monocytogenes strain. Most of the strains, particularly enterococci, were resistant to STR, TTC, and ERY (MIC50 4 μg/ml). A high percentage of staphylococci were resistant to β‐lactam antibiotics. High resistance to CLT was found in 11 strains of E. coli (MIC 256 μg/ml) and strains resistant to CMP (MIC90 16 μg/ml) were detected. The highest numbers of resistance phenotypes were found in E. coli (16) and CN staphylococci (12). Eighteen identical resistance phenotypes were demonstrated in indicator bacteria (E. coli, E. faecalis, E. faecium) and pathogens (S. aureus, CN staphylococci) isolated from the same bulk milk sample. The obtained resistance data were matched against the herd owners' information on therapeutic use of the drugs. This confrontation could not explain the findings of strains resistant to ERY or CMP. Our findings are evidence of selection of resistant strains among not only pathogenic agents, but also among indicator bacteria which can become significant carriers of transmissible resistance genes.  相似文献   

3.
This study evaluated the effects of hinokitiol (a natural antibacterial compound extracted from Thujopsis dolabrata var. hondai) and an organic acid mixture (citrate content 50%) on ruminal fermentation. Antibacterial properties were examined by measuring minimal inhibitory concentration. Hinokitiol at 1.56 µg/mL or an organic acid mixture at 1600 µg/mL inhibited Streptococcus bovis growth. The combination of 0.78 µg/mL hinokitiol and 200 µg/mL of an organic acid mixture also inhibited S. bovis growth. Both hinokitiol and the hinokitiol and an organic acid mixture combination showed strong antibacterial properties on Gram‐positive bacteria such as S. bovis, but relatively weak antibacterial activities on Gram‐negative bacteria such as Megasphaera elsdenii. Three ruminally cannulated heifers were fed a bloat‐producing diet containing barley, pelleted alfalfa meal, soybean meal and salt without long‐cut roughage to investigate the ruminal characteristics in vivo. Feeding to heifers a bloat‐producing diet containing 7.8 mg/kg hinokitiol and 0.2% of an organic acid mixture significantly decreased the increase in stable ingesta volume. Hinokitiol or an organic acid mixture did not affect ruminal volatile fatty acids, protozoa and bacteria. These results suggest that a combination of hinokitiol and an organic acid mixture might reduce frothy bloat in cattle fed high‐grain diets.  相似文献   

4.
Zhao, Z., Xue, F., Zhang, L., Zhang, K., Fei, C., Zheng, W., Wang, X., Wang, M., Zhao, Z., Meng, X. The pharmacokinetics of nitazoxanide active metabolite (tizoxanide) in goats and its protein binding ability in vitro. J. vet. Pharmacol. Therap. 33 , 147–153. The pharmacokinetics of tizoxanide (T), the active metabolite of nitazoxanide (NTZ), and its protein binding ability in goat plasma and in the solutions of albumin and α‐1‐acid‐glycoprotein were investigated. The plasma and protein binding samples were analyzed using a high‐performance liquid chromatography (HPLC) assay with UV detection at 360 nm. The plasma concentration of T was detectable in goats up to 24 h. Plasma concentrations vs. time data of T after 200 mg/kg oral administration of NTZ in goats were adequately described by one‐compartment open model with first order absorption. As to free T, the values of t1/2Ka, t1/2Ke, Tmax, Cmax, AUC, V/F(c), and Cl(s) were 2.51 ± 0.41 h, 3.47 ± 0.32 h, 4.90 ± 0.13 h, 2.56 ± 0.25 μg/mL, 27.40 ± 1.54 (μg/mL) × h, 30.17 ± 2.17 L/kg, and 7.34 ± 1.21 L/(kg × h), respectively. After β‐glucuronidase hydrolysis to obtain total T, t1/2ke, Cmax, Tmax, AUC increased, while the V/F(c) and Cl(s) decreased. Study of the protein binding ability showed that T with 4 μg/mL concentration in goat plasma and in the albumin solution achieved a protein binding percentage of more than 95%, while in the solution of α‐1‐acid‐glycoprotein, the percentage was only about 49%. This result suggested that T might have much more potent binding ability with albumin than with α‐1‐acid‐glycoprotein, resulting from its acidic property.  相似文献   

5.
β‐Defensins (BDs) are highly conserved antimicrobial peptides important in innate defence against bacteria. β‐Defensin 3 has a specific role in protecting the skin. This study quantified the minimal inhibitory concentration (MIC) of human (h)BD3 against Staphylococcus pseudintermedius isolates from atopic and healthy dogs. Single colony isolates (1 × 105 colony‐forming units/mL log phase) were cultured with doubling dilutions of hBD3 in sodium phosphate buffer from 0.8 to 50 μg/mL at 37 °C for 2 h, before adding 100 μL of tryptone soy broth and incubating for a further 20 h. Bacterial growth was assessed as the mean optical density at 540 nm corrected for background. The median MIC was 12.5 μg hBD3/mL (range 3.125–25 μg/mL; n = 22). Forty‐five percent of the isolates were inhibited at ≤6.25 μg hBD3/mL, and 90% were inhibited at ≤12.5 μg hBD3/mL. Bacterial growth was not inhibited at ≤1.6 μg hBD3/mL. There were no significant differences in the inhibition by hBD3 of isolates from atopic (median MIC 12.5 μg/mL, range 6.25–25 μg/mL, n = 14) and healthy dogs (median MIC 9.4 μg/mL, range 3.125–12.5 μg/mL, n = 8); from noninfected colonized sites (median MIC 12.5 μg/mL, range 3.125–25 μg/mL, n = 16) and infected lesions (median MIC 9.4 μg/mL, range 6.25–12.5 μg/mL, n = 6); or between sample sites (nose median MIC 12.5 μg/mL, range 6.25–25 μg/mL, n = 5; perineum median MIC 12.5 μg/mL, range 3.125–25 μg/mL, n = 7; ear median MIC 6.25 μg/mL, range 6.25–12.5 μg/mL, n = 4; lesions median MIC 9.4 μg/mL, range 6.25–12.5 μg/mL, n = 6). In conclusion, hBD3 inhibited the growth of canine S. pseudintermedius isolates in vitro irrespective of origin.  相似文献   

6.
Vallé, M., Schneider, M., Galland, D., Giboin, H., Woehrlé, F. Pharmacokinetic and pharmacodynamic testing of marbofloxacin administered as a single injection for the treatment of bovine respiratory disease. J. vet. Pharmacol. Therap. 35, 519–528. New approaches in Pharmacokinetic/Pharmacodynamic (PK/PD) integration suggested that marbofloxacin, a fluoroquinolone already licensed for the treatment of bovine respiratory disease at a daily dosage of 2 mg/kg for 3–5 days, would be equally clinically effective at 10 mg/kg once (Forcyl®), whilst also reducing the risk of resistance. This marbofloxacin dosage regimen was studied using mutant prevention concentration (MPC), PK simulation, PK/PD integration and an in vitro dynamic system. This system simulated the concentration–time profile of marbofloxacin in bovine plasma established in vivo after a single 10 mg/kg intramuscular dose and killing curves of field isolated Pasteurellaceae strains of high (minimum inhibitory concentration (MIC) MIC ≤0.03 μg/mL), average (MIC of 0.12–0.25 μg/mL) and low (MIC of 1 μg/mL) susceptibility to marbofloxacin. The marbofloxacin MPC values were 2‐ to 4‐fold the MIC values for all Mannheimia haemolytica, Pasteurella multocida tested. Marbofloxacin demonstrated a concentration‐dependant killing profile with bactericidal activity observed within 1 h for most strains. No resistance development (MIC ≥4 μg/mL) was detected in the dynamic tests. Target values for risk of resistance PK/PD surrogates (area under the curve (AUC) AUC24 h/MPC and T>MPC/TMSW ratio) were achieved for all clinically susceptible pathogens. The new proposed dosing regimen was validated in vitro and by PK/PD integration confirming the single‐injection short‐acting antibiotic concept.  相似文献   

7.
Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N‐acetylcysteine (NAC), Tris‐EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000–10,000 µg/ml and from 20,000–80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris‐EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16‐fold and eightfold higher than the MIC/MBC of NAC and Tris‐EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris‐EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm‐associated OE in dogs.  相似文献   

8.
A bovine myeloid antimicrobial peptide (BMAP‐28) is a member of the cathelicidin family which is included in the innate immune system of mammals. Recently, there have been many studies about antimicrobial peptides. This study aims to clarify whether BMAP‐28 has bactericidal activity against methicillin‐resistant Staphylococcus aureus (MRSA) and compares its activity against methicillin‐susceptible S. aureus (MSSA) and MRSA. We found that the peptide was effective in killing MRSA (minimal inhibitory concentration (MIC) range; 5–20 µg/mL). It was also revealed that MSSA (MIC range; 1.25–20 µg/mL) had two levels of susceptibility to BMAP‐28. We also examined the effect of BMAP‐28 on bacterial shape to visually show its activity. After exposure to the peptide, both MSSA and MRSA cells showed the morphological changes on their surfaces. Our results indicate that BMAP‐28 is a promising candidate for medicine against drug‐resistant bacteria.  相似文献   

9.
Albarellos, G. A., Montoya, L., Denamiel, G. A. A., Velo, M. C., Landoni, M. F. Pharmacokinetics and bone tissue concentrations of lincomycin following intravenous and intramuscular administrations to cats. J. vet. Pharmacol. Therap.  35 , 534–540. The pharmacokinetic properties and bone concentrations of lincomycin in cats after single intravenous and intramuscular administrations at a dosage rate of 10 mg/kg were investigated. Lincomycin minimum inhibitory concentration (MIC) for some gram‐positive strains isolated from clinical cases was determined. Serum lincomycin disposition was best‐fitted to a bicompartmental and a monocompartmental open models with first‐order elimination after intravenous and intramuscular dosing, respectively. After intravenous administration, distribution was rapid (T1/2(d) = 0.22 ± 0.09 h) and wide as reflected by the volume of distribution (V(d(ss))) of 1.24 ± 0.08 L/kg. Plasma clearance was 0.28 ± 0.09 L/h·kg and elimination half‐life (T1/2) 3.56 ± 0.62 h. Peak serum concentration (Cmax), Tmax, and bioavailability for the intramuscular administration were 7.97 ± 2.31 μg/mL, 0.12 ± 0.05 h, and 82.55 ± 23.64%, respectively. Thirty to 45 min after intravenous administration, lincomycin bone concentrations were 9.31 ± 1.75 μg/mL. At the same time after intramuscular administration, bone concentrations were 3.53 ± 0.28 μg/mL. The corresponding bone/serum ratios were 0.77 ± 0.04 (intravenous) and 0.69 ± 0.18 (intramuscular). Lincomycin MIC for Staphylococcus spp. ranged from 0.25 to 16 μg/mL and for Streptococcus spp. from 0.25 to 8 μg/mL.  相似文献   

10.
Objectives To examine the role of spinal 5‐hydroxytryptamine (5‐HT) binding sites in nociceptive processing in conscious sheep and to study the role of 5‐HT agonists in mediating analgesia. Study design Prospective controlled study. Animals Nine adult healthy female sheep (Swaledale, Swaledale‐cross or Clun Forest) weighing 45–65 kg. Methods Intrathecal (IT) catheters were implanted at the cervical (n = 5) or lumbar (n = 4) level of the spinal cord under general anaesthesia. At least 1 week later, and at 1 week intervals thereafter, the effects of intrathecal Ringer's solution (control), xylazine (100 µg), 5‐HT creatinine sulphate (200, 400 and 800 µg), RU24969 (200 µg), α‐Methyl‐5‐HT and 1‐(3‐Chlorophenyl)‐biguanide (CPBG) on the mechanical nociceptive threshold (MT) were studied. Results were plotted as mean variable versus time curves. Areas under portions of the curves (0–30 and 0–60 minutes) were measured and expressed as mean ± standard error. Differences between values for control and drug trials were examined using the two‐tailed Student's t‐test. Results Baseline values of MT were lower on the hind limbs than on the forelimbs. Intrathecal Ringer's solution did not alter MT in the cervical or lumbar region. Xylazine (100 µg) produced a characteristic elevation in MT between 5 and 60 + minutes. Lumbar IT injection of 5‐HT (800 µg) raised the MT more than cervical injection, while cervical injection of RU24969 (200 µg) raised the MT more than lumbar administration. Cervical IT injection of α‐Me‐5‐HT (500 µg) produced a marked and significant increase in MT while lumbar application had no effect. CPBG (500 µg) injection caused no significant effect on MT with either cervical or lumbar applications. Conclusions The activation of 5‐HT1 and 5‐HT2 receptors particularly at the cervical level appears to be involved in spinal nociceptive processing in the sheep. Clinical relevance These effects, which lasted about 60 minutes, may have an implication in the development of new analgesic strategies for animals.  相似文献   

11.
The aim of this study was to determine the in vitro antifungal activity of several antifungal drugs (posaconazole, nystatin, miconazole and clotrimazole) against Malassezia pachydermatis with microdilution and agar dilution techniques. Malassezia pachydermatis isolates were obtained from the skin and ears of dogs. Tests on solid media were performed using 25‐well Petri dishes (2 mL/well containing Sabouraud's dextrose agar and diluted antifungal drug) inoculated with 5 μL suspensions of M. pachydermatis. Microtitre broth dilution used 96‐well microtitre plates containing Sabourauds dextrose broth and appropriate dilutions of antifungal drugs, inoculated with 10 μL standard suspensions of M. pachydermatis. Plates were inoculated in duplicate and incubated at 30°C for 5 days and growth assessed. The four antifungal drugs were tested in 10 dilutions (4.0‐0.007 μg/mL for posaconazole, and 32‐‐0.06 μg/mL for clotrimazole, miconazole and nystatin). Results obtained for 83 strains of M. pachydermatis and a control reference strain (CBS 1879) exhibited the same pattern. Results of the MIC between microtitre and agar methodologies showed no significant differences (≤ 2‐fold) across all drugs. For both solid and liquid methods, posaconazole was the most effective antifungal drug of the four tested with MIC90 of 1–2 μg/mL for posaconazole, 16–32 μg/mL for clotrimazole, and ≥ 32 μg/mL for miconazole and nystatin. Funding: Schering‐Plough.  相似文献   

12.
The cephalosporin antimicrobial drug cefquinome was administered to yellow cattle intravenously (i.v.) and intramuscularly (i.m.) at a dose of 1 mg/kg of body weight in a two‐period crossover study. The pharmacokinetic (PK) properties of cefquinome in serum, inflamed tissue‐cage fluid (exudate), and noninflamed tissue‐cage fluid (transudate) were studied using a tissue‐cage model. The in vitro and ex vivo activities of cefquinome in serum, exudate, and transudate against a pathogenic strain of Pasteurella multocida (P. multocida) were determined. A concentration‐independent antimicrobial activity of cefquinome was confirmed for levels lower than 4 × MIC. Integration of in vivo pharmacokinetic data with the in vitro MIC provided mean values for the time that drug levels remain above the MIC (T > MIC) in serum was 14.10 h after intravenous and 14.46 h after intramuscular dosing, indicating a likely high level of effectiveness in clinical infections caused by P. multocida of MIC 0.04 μg/mL or less. These data may be used as a rational basis for setting dosing schedules, which optimize clinical efficacy and minimize the opportunities for emergence of resistant organisms.  相似文献   

13.
The effects of in vitro exposure of porcine spermatozoa to zearalenone (ZEN) and α‐zearalenol (α‐ZOL) were studied by evaluating several parameters of an in vitro fertilization (IVF) system. For this purpose, boar spermatozoa cultured with semen storage medium containing 0 (control), 10 and 1000 µg/L of ZEN and α‐ZOL for 1 week at 5°C were used for IVF of in vitro matured oocytes. Overall, there were no significant differences in the rates of total penetration, monospermic fertilization, and polyspermic fertilization of oocytes inseminated with spermatozoa from the different groups. Similarly, ZEN and α‐ZOL at 10 and 1000 µg/L did not have detrimental effects on the cleavage and development to blastocysts of oocytes after in vitro fertilization. Although the motility, viability, and plasma membrane integrity of spermatozoa significantly decreased after 3 weeks of storage compared to non‐stored spermatozoa (P < 0.05), ZEN and α‐ZOL at the evaluated concentrations did not exert detrimental effects on the above parameters, even after 3 weeks of storage. These results indicate that prolonged exposure of boar spermatozoa to ZEN and α‐ZOL up to 1000 µg/L under reduced metabolic conditions does not affect their in vitro function.  相似文献   

14.
We previously described that supplementary garlic, onion and purple sweet potato (PSP) enhance humoral immune response in White Leghorn chickens. In the present in vitro study, we investigated the effects of garlic (GE), onion (OE) and PSP (PSPE) extracts on proliferation, interleukin (IL)‐2 and interferon (INF)‐γ gene expression of stimulated lymphocytes. The effects on microbicidal activity, reactive oxygen species (ROS) and nitric oxide (NO) productions of stimulated peritoneal macrophages were studied as well. The results showed that GE augmented Concanavalin A (ConA)‐induced splenocytes (4, 8 and 16 µg/mL) and thymocytes (2, 4 and 8 µg/mL) proliferations, and gene expression of IL‐2 (8 and 16 µg/mL) and INF‐γ (16 µg/mL). None of the examined extracts had mitogenic effect nor stimulated bursacytes response to phorbol 12‐myristate 13‐acetate (PMA). Macrophages exhibited superior microbicidal activity and ROS production with GE at 4 and 8 µg/mL and with OE at 25.6 µg/mL. None of the extracts showed stimulatory effects on NO production. The extracts showed concentration‐dependent inhibitory effects on all measured parameters at higher concentrations. Taken together, it is likely that garlic has direct stimulatory effects on immune cell functions, whereas the in vitro inhibitory effects of onion and PSP were likely attributed to high flavonoid contents.  相似文献   

15.
Data from 19 Japanese Black multiparous cows were collected to clarify the relationships among immunoglobulin (Ig) G, IgA, β‐carotene, vitamin A and α‐tocopherol contents in colostrum of cows in order to evaluate the role of fat‐soluble vitamins on colostral IgG and IgA production. Mean colostral IgG was 141 mg/mL, ranging from 65 to 208 mg/mL, whereas mean colostral IgA was 8.7 mg/mL, ranging from 1.0 to 34.6 mg/mL. Colostral IgG increased with aging in multiparous cows. There were positive correlations between colostral IgG and colostral vitamin A or colostral α‐tocopherol in cows, and the higher adjusted R2 was obtained in the prediction model of colostral IgG from age and colostral vitamin A. Colostral vitamin A was positively correlated with colostral β‐carotene or colostral α‐tocopherol in cows, but there were no relationships between colostral IgA and colostral IgG or colostral fat‐soluble vitamins. These results indicate that fat‐soluble vitamin contents in colostrum of cows may change in similar patterns and high colostral vitamin A is related with high colostral IgG.  相似文献   

16.
The single‐dose disposition kinetics of the antibiotic marbofloxacin were determined in Chinese soft‐shelled turtles (n = 10) after oral and intramuscular (i.m.) dose of 10 mg/kg bodyweight. The in vitro and ex vivo activities of marbofloxacin in serum against a pathogenic strain of Aeromonas hydrophila were determined. A concentration‐dependent antimicrobial activity of marbofloxacin was confirmed for levels lower than 4 × MIC. For in vivo PK data, values of AUC: minimum inhibitory concentration (MIC) ratio for serum were 1166.6 and 782.4 h, respectively, after i.m. and oral dosing of marbofloxacin against a pathogenic strain of A. hydrophila (MIC = 0.05 μg/mL). The ex vivo growth inhibition data after oral dosing were fitted to the inhibitory sigmoid Emax equation to provide the values of AUC/MIC required to produce bacteriostasis, bactericidal activity and elimination of bacteria. The respective values were 23.79, 36.35 and 126.46 h. It is proposed that these findings might be used with MIC50 or MIC90 data to provide a rational approach to the design of dosage schedules, which optimize efficacy in respect of bacteriological as well as clinical cures.  相似文献   

17.
The in-vitro activity of enrofloxacin against 117 strains of bacteria isolated from bustards was determined. Minimum inhibitory concentrations for 72% of the Proteus spp., E. coli, Salmonella spp. and Klebsiella spp. (n = 61) and for 48% of the Streptococci spp. and Staphylococci spp. (n = 31) were 0.5 μ g/mL. The minimum inhibitory concentration (MIC) of 76% of Pseudomonas spp. (n = 25) was 2 μg/mL. Fourteen strains were resistant to concentrations 128 μg/mL. The elimination half-lives (t½ elim β) (mean± SEM) of 10 mg/kg enrofloxacin in eight houbara bustards (Chlamydotis undulata) were 6.80± 0.79, 6.39± 1.49 and 5.63± 0.54 h after oral (p.o.), intramuscular (i.m.) and intravenous (i.v.) administration, respectively. Enrofloxacin was rapidly absorbed from the bustard gastro-intestinal tract and maximum plasma concentrations of 1.84± 0.16 μg/mL were achieved after 0.66± 0.05 h. Maximum plasma concentration after i.m. administration of 10 mg/kg was 2.75± 0.11 μg/mL at 1.72± 0.19 h. Maximum plasma concentration after i.m. administration of 15 mg/kg in two birds was 4.86 μg/mL. Bioavailability was 97.3± 13.7% and 62.7± 11.1% after i.m. and oral administration, respectively. Plasma concentrations of enrofloxacin 0.5 μg/mL were maintained for at least 12 h for all routes at 10 mg/kg and for 24 h after i.m. administration at 15 mg/kg. Plasma enrofloxacin concentrations were monitored during the first 3 days of treatment in five houbara bustards and kori bustards (Ardeotis kori) with bacterial infections receiving a single daily i.m. injection of 10 mg/kg for 3 days. The mean plasma enrofloxacin concentrations in the clinical cases at 27 and 51 h (3.69 and 3.86 μg/mL) and at 48 h (0.70 μg/mL) were significantly higher compared with the 3 h and 24 h time intervals from clinically normal birds. The maximum plasma concentration (Cmax)/MIC ratio was ranked i.v. (10/mg/kg) > i.m. (15 mg/kg) > i.m. (10 mg/kg) > oral (10 mg/kg), but it was only higher than 8:1 for i.v and i.m. administrations of enrofloxacin at 10 mg/kg and 15 mg/kg, respectively, against a low MIC (0.5 μg/mL). A dosage regimen of 10 mg/kg repeated every 12 h, or 15 mg/kg repeated every 24 h, would be expected to give blood concentrations above 0.5 μg/mL and hence provide therapeutic response in the bustard against a wide range of bacterial infections.  相似文献   

18.
The purpose of the present study was to determine the prevalence of antibiotic resistance, with special attention to vancomycin, in 104 strains of Enterococcus, which is the sentinel bacterium isolated from dog and cat faeces samples. The phenotypic characterization of the isolates classified them as E. faecium (58%), E. avium (41%) and E. faecalis (1%). Sensitivity testing used the diffusion method according to the recommendations of CASFM (Comité de l'Antibiogramme de la Société Française de Microbiogie), to oxacillin, amoxycillin, amoxycilin + clavulanic acid, ampicillin, piperacillin, cefoperazone, imipenem, enrofloxacin, ciprofloxacin, οfloxacin, nalidixic acid, tetracycline, lincomycin, erythromicin and vancomycin. Minimum inhibitory concentration (MIC) determination by E test revealed a MIC to vancomycin of between 0.5 μg/ml and 3 μg/ml. All the strains were resistant to nalidixic acid, erythromycin, cefoperazone and oxacillin. We detected resistance to amoxycillin + clavulanic acid in 1.9% of isolates, to amoxycillin in 4.8%, to piperacillin in 13.5%, and to ampicillin in 21.2% of strains. A high prevalence of antibiotic resistance to lincomycin, tetracycline, enrofloxacin, ciprofloxacin and ofloxacin was found in 98.1%, 95.2%, 76.9%, 73.1% and 64.4% of strains, respectively. Resistance to vancomycin was not found, which indicates that there is no transmission risk of vancomycin‐resistant enterococcal strains to man or transfer of their resistance genes to other bacteria belonging to the endogenous flora of humans.  相似文献   

19.
Körber‐Irrgang, B., Wetzstein, H.‐G., Bagel‐Trah, S., Hafner, D., Kresken, M. Comparative activity of pradofloxacin and marbofloxacin against coagulase‐positive staphylococci in a pharmacokinetic–pharmacodynamic model based on canine pharmacokinetics. J. vet. Pharmacol. Therap.  35 , 571–579. Pradofloxacin (PRA), a novel veterinary 8‐cyano‐fluoroquinolone (FQ), is active against Staphylococcus pseudintermedius, the primary cause of canine pyoderma. An in vitro pharmacokinetic–pharmacodynamic model was used to compare the activities of PRA and marbofloxacin (MAR) against three clinical isolates of S. pseudintermedius and reference strain Staphylococcus aureus ATCC 6538. Experiments were performed involving populations of 1010 CFU corresponding to an inoculum density of approximately 5 × 107 CFU/mL. The time course of free drug concentrations in canine serum was modelled, resulting from once daily standard oral dosing of 3 mg of PRA/kg and 2 mg of MAR/kg. In addition, experimentally high doses of 6 mg of PRA/kg and 16 mg of MAR/kg were tested against the least susceptible strain. Viable counts were monitored over 24 h. At concentrations associated with standard doses, PRA caused a faster and more sustained killing than MAR of all strains. The ratios of free drug under the concentration–time curve for 24 h over MIC and the maximum concentration of free drug over MIC were at least 90 and 26, and 8.5 and 2.1 for PRA and MAR, respectively. At experimentally high doses, PRA was superior to MAR in terms of immediate killing. Subpopulations with reduced susceptibility to either FQ did not emerge. We conclude that PRA is likely to be an efficacious therapy of canine staphylococcal infections.  相似文献   

20.

  1. The aim of this study was to determine the antibiotic susceptibility of 93 Lactobacillus strains isolated from domestic geese raised on Polish farms. The minimal inhibitory concentration (MIC) of 13 antimicrobial substances was determined by the broth microdilution method.

  2. All strains were sensitive to the cell wall inhibitors ampicillin and amoxicillin (MIC ≤ 8 μg/ml). Resistance to inhibitors of protein synthesis and to fluoroquinolone inhibitors of replication was found in 44.1% and 60.2% of isolates, respectively; 26.9% strains were resistant to neomycin (MIC ≥ 64 μg/ml), 23.6% to tetracycline (MIC ≥ 32 μg/ml), 15% to lincomycin (MIC ≥ 64 μg/ml), 18.3% to doxycycline (MIC ≥ 32 μg/ml), 9.7% to tylosin (MIC ≥ 32 μg/ml), 56% to flumequine (MIC ≥ 256 μg/ml) and 22.6% to enrofloxacin (MIC ≥ 64 μg/ml).

  3. Bimodal distribution of MICs indicative of acquired resistance and unimodal distribution of the high MIC values indicative of intrinsic resistance were correlated with Lactobacillus species. Eleven (11.8%) strains displayed multiple resistance for at least three classes of antibiotics.

  4. Data derived from this study can be used as a basis for reviewing current microbiological breakpoints for categorisation of susceptible and resistant strains of Lactobacillus genus and help to assess the hazards associated with the occurrence of drug resistance among natural intestinal microflora.

  相似文献   

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