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2.
Staphylococcus intermedius isolates (n = 106), including 44 dog isolates and 62 pigeon isolates, were examined for their susceptibility to ampicillin, cephalexin, erythromycin, gentamicin, kanamycin, lincomycin, norfloxacin, oxacillin, tetracycline, and vancomycin by standard disk-diffusion test. The frequencies of resistance to ampicillin, kanamycin, and tetracycline were significantly higher in dog isolates than pigeon isolates (95.5% vs. 0%, 31.8% vs. 0%, and 45.5% vs. 9.7%, respectively; P < 0.01). Antimicrobial resistance patterns of dog isolates and pigeon isolates were categorized respectively into nine and five distinct profiles. Significantly higher occurrence of resistance to two or more antimicrobials was observed in dog isolates than pigeon isolates (54.5% vs. 12.9%; P < 0.01) and also in domesticated pigeon isolates than non-domesticated pigeon isolates (53.3% vs. 0%; P < 0.01).  相似文献   

3.
Seo KS  Lim JY  Yoo HS  Bae WK  Park YH 《Veterinary microbiology》2005,106(3-4):225-233
Vancomycin-resistant enterococci (VRE) have emerged as an important nosocomial pathogen. Since 1989, a rapid increase in the incidence of enterococcal bacteremia and endocarditis by VRE has been reported. The use of avoparcin in animal husbandry is reportedly associated with the appearance of VRE. In this study, a multiplex polymerase chain reaction (PCR) method was established to detect and differentiate resistant types of enterococci, which specifically amplify the four van genes that encode vancomycin resistance elements. Using this method, we investigated the incidence rates and types of VRE from two types of farms: those that had used avoparcin and those that had not used avoparcin. A total of 1091 animal fecal samples were collected from 70 pig farms and 32 poultry farms. A total of 425 enterococci were isolated from the fecal samples. Among the 425 isolates, six showed a pattern of high-level vancomycin resistance (Minimal Inhibitory Concentration, MIC: 64-256 microg/ml). Out of six high-level VRE, three were isolated from poultry farms that had used avoparcin and three were not. The six high-level VRE harbored the vanA gene. Sixty-seven of 425 isolates that showed a pattern of low-level vancomycin resistance (MIC: 4-8 microg/ml) were associated with the presence of vanC-1 or vanC-2/3 gene. We also performed a repetitive extragenic palindromic PCR (rep-PCR) method to compare the genetic relatedness between the high-level VRE of six animal isolates and 31 human isolates. None of the animal isolates had a similar rep-PCR pattern as the human isolates but similarities between human VRE isolates were observed.  相似文献   

4.
An epidemiologic study was conducted to investigate the incidence and characterize the antimicrobial resistance determinants, analyzing plasmid profiles, and establishing the genetic relationship among β-lactam-resistant isolates of Salmonella Infantis from broilers in Southern Japan. A total of 120 isolates were recovered from 56 flocks belonging to 44 holdings during 2004–2006. The percentages of resistance were as follows: ampicillin (24%), cephalothin (23%), cefoxitin (0%), ceftazidime (11%), cefotaxime (11%), chloramphenicol (0%), kanamycin (7.5%), ofloxacin (20%), oxytetracycline, streptomycin and sulfamethoxazole (100%) and trimethoprim (75%). The incidence of blaTEM-encoded β-lactam resistance in 2004–2006 was significantly higher than in 1998–2003 (P < 0.001). BlnI-digested PFGE patterns generated two related clusters implicated in the dissemination of β-lactam resistance. Two types of plasmid profiles were observed and two plasmids of ca. 50 and 180-kb size were carried by β-lactam-resistant isolates. Streptomycin resistance was conferred by aadA1 (n = 116), aadA1-aadA2 (n = 1), and aadA1-strA-strB (n = 3). Resistances to kanamycin, oxytetracycline, sulfamethoxazole and trimethoprim were conferred by aphA1 (n = 9, 100%), tetA (n = 120, 100%) sul1 (n = 120, 100%) and dfrA5 (n = 90, 100%), respectively. Two types of class 1 integrons were detected: 1.0 kb (n = 120) and, 1.0/1.5 kb (n = 3). Integrons of 1.0/1.5 kb were found in isolates with the aadA1-strA-strB gene combination. For the first time, all S. Infantis isolates showed resistance to at least three classes of antimicrobial agents; and the intestinal tract of healthy poultry was a reservoir of the extended-spectrum cephalosporin-resistant isolates of serovar Infantis.  相似文献   

5.
This study describes and compares the pharmacokinetics of a single 7.5 mg/kg dose of cephalexin monohydrate oil-based 20% suspension after its administrations to six cows by the intramuscular (i.m.) and subcutaneous (s.c.) routes, and to five calves by the i.m. route. Significantly (P < 0.05) higher peak plasma concentrations (5.6 ± 0.79 μg/ml versus 3.93 ± 1.24 μg/ml) and lower half-life (1.81 ± 0.56 h versus 4.21 ± 0.82 h) and mean residence time (4.12 ± 1.07 h versus 6.63 ± 0.85 h) were obtained after i.m. administration when compared to the s.c. administration to cows. No differences were found between pharmacokinetic parameters calculated for cows and calves. Cephalexin plasma concentrations remained above 0.5–0.75 μg/ml for 11–14 h and 8–9 h after the s.c. and i.m. administrations, respectively. Thus, route of administration may be an important issue to be considered when calculating dosage schedules for successful treatments and safe withdrawal times for veterinary medicines.  相似文献   

6.
We describe the morphological, biological, and molecular characteristics of Cryptosporidium pig genotype II and propose the species name Cryptosporidium scrofarum n. sp. to reflect its prevalence in adult pigs worldwide. Oocysts of C. scrofarum are morphologically indistinguishable from C. parvum, measuring 4.81–5.96 μm (mean = 5.16) × 4.23–5.29 μm (mean = 4.83) with a length to width ratio of 1.07 ± 0.06 (n = 400). Oocysts of C. scrofarum obtained from a naturally infected pig were infectious for 8-week-old pigs but not 4-week-old pigs. The prepatent period in 8-week-old Cryptosporidium-naive pigs was 4–6 days and the patent period was longer than 30 days. The infection intensity of C. scrofarum in pigs was generally low, in the range 250–4000 oocysts per gram of feces. Infected pigs showed no clinical signs of cryptosporidiosis and no pathology was detected. Cryptosporidium scrofarum was not infectious for adult SCID mice, adult BALB/c mice, Mongolian gerbils (Meriones unguiculatus), southern multimammate mice (Mastomys coucha), yellow-necked mice (Apodemus flavicollis), or guinea pigs (Cavia porcellus). Phylogenetic analyses based on small subunit rRNA, actin, and heat shock protein 70 gene sequences revealed that C. scrofarum is genetically distinct from all known Cryptosporidium species.  相似文献   

7.
The increasing prevalence of antimicrobial resistances is now a worldwide problem. Investigating the mechanisms by which pets harboring resistant strains may receive and/or transfer resistance determinants is essential to better understanding how owners and pets can interact safely. Here, we characterized the genetic determinants conferring resistance to β-lactams and quinolones in 38 multidrug-resistant Escherichia coli isolated from fecal samples of dogs, through PCR and sequencing. The most frequent genotype included the β-lactamase groups TEM (n = 5), and both TEM + CTX-M-1 (n = 5). Within the CTX-M group, we identified the genes CTX-M-32, CTX-M-1, CTX-M-15, CTX-M-55/79, CTX-M-14 and CTX-M-2/44. Thirty isolates resistant to ciprofloxacin presented two mutations in the gyrA gene and one or two mutations in the parC gene. A mutation in gyrA (reported here for the first time), due to a transversion and transition (TCG → GTG) originating a substitution of a serine by a valine in position 83 was also detected. The plasmid-encoded quinolone resistance gene, qnrs1, was detected in three isolates. Dogs can be a reservoir of genetic determinants conferring antimicrobial resistance and thus may play an important role in the spread of antimicrobial resistance to humans and other co-habitant animals.  相似文献   

8.
Rectal smears of calves, cows and young bulls, as well as cloacal smears of house sparrows (Passer domesticus), from farms at the villages of Šumice and Troskotovice, Czech Republic, were examined for E. coli resistant to 12 antimicrobials. The resistant isolates were tested for antimicrobial-resistance genes and integrons. Totals of 40% (n = 183), 3% (n = 95), 0% (n = 33), and 9% (n = 54) of Escherichia coli isolates from calves, cows, young bulls and house sparrows, respectively, were antimicrobial resistant. The following genes were identified in cattle E. coli isolates: tetA, tetB (isolates resistant to tetracycline), blaTEM (beta-lactams), strA, aadA (streptomycin), sul1, sul2 (sulphonamides), and cat, floR (chloramphenicol). Seven of 16 antimicrobial-resistant calf isolates from the Šumice farm possessed class 1 integrons with the aadA1 gene cassette integrated, 1 kb in size. On the Troskotovice farm, eight of 57 antimicrobial-resistant calf isolates possessed class 1 integrons. Integrons of 1.5 kb with the dhfr1- aadA1 gene cassette were found in four isolates, followed by a 1 kb integron with the aadA1 gene found in three isolates, and a 1.7 kb integron with the dhfr17-aadA5 gene cassette and the phenotype ASSuTSxtNaCipCCfG. The prevalence of resistant E. coli in calves compared to adult cattle was much higher and probably was influenced by oral antimicrobial usage in calves, feeding with milk and colostrum from treated cows, as well as mechanisms unrelated to antimicrobial drug selection. Although house sparrows lived together with the cattle and came into contact with cattle waste on the farm, they were not infected by resistant E. coli isolates with the same characteristics as those found in cattle.  相似文献   

9.
Escherichia coli-associated diarrhoea is an important disease adversely affecting the pig industry. This study was conducted to investigate the frequency of virulence factors expressed by E. coli strains isolated from suckling pigs with diarrhoea in China. A total of 381 E. coli strains, obtained from 290 faecal samples from pigs on 38 farms, were tested for fimbriae (K88, K99, 987P, F41, F18, F17), non-fimbrial adhesins (AIDA-I, paa, CS31A, eae, saa), enterotoxin (LT-I, LT-II, STa, STb, EAST1), Shiga toxin (Stx1, Stx2, Stx2e), pathogenicity islands (HPI, LEE), α-haemolysin (hlyA), afa8 gene cluster (afaD, afaE) and sepA genes by PCR. Out of the 381 isolates, 206 carried at least one virulence gene. Of the 206 virulence positive isolates, the virulence factor genes detected were EAST1 (n = 120), irp2 (n = 59), paa (n = 50), STb (n = 41), AIDA-I (n = 34), LT-I (n = 23), ler (n = 11), hlyA (n = 9), K88 (n = 8), eae (n = 8), STa (n = 7), sepA (n = 6), F18 (n = 5), afaD (n = 3), afaE (n = 3), K99 (n = 2) and Stx2e (n = 1), with most isolates carrying multiple virulence genes. These results demonstrate that relatively few isolates from the study population express K88, K99, LT-I or STa, but that EAST1 (58%), irp2 (29%), AIDA-I (16.5%), paa (24%) and STb (20%) are frequent virulence factors expressed by E. coli strains isolated from suckling pigs with diarrhoea in China.  相似文献   

10.
Ivermectin (IVM) resistance of Cooperia spp. in cattle has become an increasing and global problem. The early detection of anthelmintic resistance (AR) is important to propose strategies to slow down the development of resistance and requires sensitive, reliable, economic high-throughput and practical tests. The purpose of the present study was to apply a larval migration inhibition test (LMIT) for evaluating IVM and MOX efficacy against well-characterized field isolates of Cooperia spp. infecting cattle in Brazil. Eight isolates were used for IVM and seven for MOX. The following EC50 values of IVM were observed for the isolates: susceptible, 1.16 ηmol; Nova Alvorada do Sul I, 4.09 ηmol (RF = 3.52); Campo Grande BNA, 3.57 ηmol (RF = 3.07); Campo Grande TBR, 4.09 ηmol (RF = 3,52); Nova Alvorada do Sul II, 2.50 ηmol (RF = 2.15); Bandeirantes, 11.35 ηmol (RF = 9.78); Campo Grande II, 6.03 ηmol (RF = 5.20); and Porto Mortinho, 8.63 ηmol (RF = 7.44). For MOX, the following EC50 values were observed: susceptible, 0.75 ηmol; Campo Grande BNA, 0.93 ηmol (RF = 1.24); Campo Grande TBR, 0.36 ηmol (RF = 0.48); Nova Alvorada do Sul II, 2.57 ηmol (RF = 3.42); Bandeirantes, 1.43 ηmol (RF = 1.90); Campo Grande II, 1.08 ηmol (RF = 1.44); and Porto Mortinho, 0.49 ηmol (RF = 0.65). The LMIT used in the present study can be a useful tool for in vitro evaluation of IVM, but not of MOX. However, such methodology cannot be used in large-scale studies yet. The isolates of Cooperia spp. showed various degrees of resistance to IVM, though remaining susceptible to MOX.  相似文献   

11.
A tissue cage (TC) model was used to evaluate the pharmacokinetics and ex vivo pharmacodynamics of cefquinome after intravenous (IV) and intramuscular (IM) administration to piglets at 2 mg/kg bodyweight. The mean values of area under the concentration–time curve (AUC) were 21.28 (IV) and 21.37 (IM) μg h/mL for serum, and 17.40 (IV) and 16.57 (IM) μg h/mL for TC fluid (TCF), respectively. Values of maximum concentration (Cmax) were 6.15 μg/mL (serum) and 1.15 μg/mL (TCF) after IM administration. The elimination half-lives (t1/2β) in TCF (10.63 h IV and 11.81 h IM) were significantly higher than those in serum (2.33 h IV and 2.30 h IM) (P < 0.05). The values of AUCTCF/AUCserum (%) after IV and IM administration were 82.4% and 80.7%, respectively.The ex vivo time-kill curves were established for serum and TCF samples using Escherichia coli ATCC 25922. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values of cefquinome against E. coli were 0.030 and 0.060 μg/mL in Mueller–Hinton broth, and 0.032 and 0.064 μg/mL in both serum and TCF, respectively. The ex vivo growth inhibition data of TCF after IM administration were fitted to the sigmoid Emax model; AUC24h/MIC was 35.01 h for bactericidal activity and 44.28 h for virtual eradication, respectively. The findings from this study suggest that cefquinome may be therapeutically effective in diseases of pigs caused by E. coli when used at a dose rate of 1.33 mg/kg administered every 24 h for organisms with MIC90 ⩽ 0.50 μg/mL.  相似文献   

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13.
《Veterinary parasitology》2015,207(3-4):309-317
The present study aimed to determine the susceptibility of 17 Rhipicephalus (Boophilus) microplus populations, originating in the Southeast and Southern regions of Brazil, to different ivermectin concentrations (200, 500 and 630 μg/kg), administered through subcutaneous or topical (pour-on) routes. R. (B.) microplus populations from the states of Minas Gerais (seven populations), São Paulo (seven populations) and Paraná (three populations) were chosen for the tests. The selected cattle were allocated to treatment groups on day 0, and block formation was based on the arithmetic mean of female ticks (4.5–8.0 mm long) counted on three consecutive days (−3, −2 and −1). To evaluate the therapeutic and residual efficacies of these formulations, tick counts (females ranging from 4.5 to 8.0 mm long) were performed on days 3, 7 and 14 post-treatment, and continued on a weekly basis thereafter until the end of each experiment. The results obtained throughout this study, utilizing field efficacy studies, allowed us to conclude that the resistance of R. (B.) microplus against 200 and 500 μg/kg ivermectin is widely disseminated because all tick populations that had contact with these specific concentrations were diagnosed as resistant. However, it is possible to infer that R. (B.) microplus resistance against 630 μg/kg ivermectin was also widespread, diagnosed at six of ten analyzed properties. Resistance of these ectoparasites to 630 μg/kg ivermectin is most likely emerging in three other populations of R. (B.) microplus. Strategies of resistance management need to be quickly determined to keep the selection pressure at a minimum level in Brazil.  相似文献   

14.
Brucellosis is a highly contagious zoonotic infection affecting livestock and human beings. The disease has been reported worldwide except in few countries where it has been eradicated. The prevalence of brucellosis among cattle from 11 farms having a history of abortions was studied. A total of 481 samples comprising of blood, milk, vaginal swabs, vaginal discharges, placental tissues and fetal tissues were collected from 296 animals. Clinical samples were processed for the isolation of Brucella. Serum samples (n = 296) were tested by Rose Bengal Plate Test (RBPT) and indirect ELISA. A total of 90 (30.40%) and 123 (41.55%) samples were positive by RBPT and indirect ELISA, respectively. Also 27.02% samples were positive by both the tests. Brucella isolates (n = 8) were recovered from clinical samples using Brucella selective media. All the isolates demonstrated PCR amplification for the bcsp31 and IS711 genes. Amplification of Brucella abortus specific primer was demonstrated by all the isolates in AMOS PCR indicating isolates to be of either B. abortus biotype 1, 2 or 4. Risk factors for transmission of brucellosis among cattle population were studied by field surveys. It was observed that lack of awareness about brucellosis (OR = 8.739, P = 0.138) and inadequate floor space (OR = 0.278, P = 0.128) were crucial risk factors for transmission of bovine brucellosis.  相似文献   

15.
《Veterinary microbiology》2015,175(1):114-122
Mannheimia haemolytica is the primary bacterial agent in the bovine respiratory disease complex. It is thought that M. haemolytica colonizes the tonsillar crypts of cattle as a commensal and subsequently descends into the lungs to cause disease. Many bacterial species persist in the host as biofilms. There is limited information about the ability of M. haemolytica to form biofilms. The aim of this study was to develop an in vitro model for M. haemolytica biofilm formation. We found that M. haemolytica required at least 36 h to form robust biofilms on plastic in vitro when incubated in RPMI-1640 tissue culture medium at 37 °C, with maximal biofilm formation being evident at 48 h. Biofilm formation was inhibited by adding the monosaccharides d(+) galactose and d(+) mannose to the growth medium. Addition of antibodies to the M. haemolytica surface protein OmpA also reduced biofilm formation. Upon evaluating the macromolecules within the biofilm extracellular polymeric substance we found it contained 9.7 μg/cm2 of protein, 0.81 μg/cm2 of total carbohydrate, and 0.47 μg/cm2 of extracellular DNA. Furthermore, proteinase K treatment significantly decreased biofilms (P < 0.05) while α-amylase and micrococcal nuclease decreased biofilms to a lesser extent. M. haemolytica biofilm cells were more resistant than planktonic cells to the antibiotics florfenicol, gentamicin, and tulathromycin. These results provide evidence that M. haemolytica can form biofilms, which could contribute to its ability to persist as a commensal in the bovine upper respiratory tract.  相似文献   

16.
The aim of this study was to determine whether hospitalisation of horses leads to increased antimicrobial resistance in equine faecal Escherichia coli isolates. E. coli were cultured from faecal samples of horses on admission and after 7 days of hospitalisation; antimicrobial susceptibility was determined for eight antimicrobial agents. Resistance profiles of E. coli isolates were grouped into clusters, which were analysed to determine resistance patterns. Resistance to 7/8 antimicrobial agents and multi-drug resistance (MDR; resistance to ?3 antimicrobial classes) were significantly higher after 7 days of hospitalisation. Forty-eight resistance profiles were identified; 15/48 were present on day 0 only, 16/48 on day 7 only and 17/48 at both times of sampling. There was a significant association between day 7 profiles and resistance detected to an increased number of antimicrobial agents. Hospitalisation of horses for 7 days resulted in alterations in equine faecal E. coli antimicrobial resistance profiles.  相似文献   

17.
The study was undertaken to determine the efficacy of hydro-methanolic (1:1) extract of tamarind (Tamarindus indica L.) fruit pulp in removing body fluoride burden. Thirty rats were divided into five groups. Keeping no fluoride group as the control, rats of no treatment, low dose, middle dose and high dose groups received sodium fluoride orally at the rate of 200 mg per kg body weight daily for 14 weeks. Rats of low dose, middle dose and high dose group simultaneously received tamarind fruit pulp extract at three doses, viz. 25 (low), 50 (medium) and 100 mg (high) per kg body weight orally, respectively. Fluoride concentration in blood, urine and long bone of experimental rats was monitored to assess the efficacy of the extract. Mean serum fluoride concentration in fluoride exposed rats was 0.145 ± 0.009 and 0.783 ± 0.042 μg/ml on days 0 and 98. In comparison, fluoride concentrations in tamarind treated rats were 0.179 ± 0.021 and 0.633 ± 0.015; 0.179 ± 0.021 and 0.502 ± 0.025 and 0.176 ± 0.021 and 0.498 ± 0.030 μg/ml in low, medium and high dose groups, respectively on day 0 and day 98 of the experiment. There was a significant (p ⩽ 0.01) increase in urinary fluoride excretion from day 28 onwards. The mean fluoride concentration in long bones of treated rats was significantly lower than the values recorded in fluoride exposed rats. These findings suggest that concomitant use of tamarind fruit pulp extract can reduce fluoride concentration in blood and bone and enhanced urinary excretion, indicating the ameliorative potential of fruits of tamarind in fluoride toxicity.  相似文献   

18.
Salmonella is the second most frequent cause of foodborne illness in the European Union (EU), so EU enforced legislation to achieve a reduction in Salmonella prevalence in the swine sector. To set the reduction target each country carried out a baseline survey to estimate Salmonella prevalence. The aim of our study was to identify risk factors for the presence of Salmonella in breeding pigs based on the data of the Baseline Study for Salmonella in Breeding Pigs in Portugal. In total, 1670 pen fecal samples from 167 herds were tested by culture and 170 samples tested positive. Along with the collection of the samples a survey was applied to collect information about the herd management and potential risk factors. Multilevel analysis was applied to the data using generalized linear mixed models and a logit link function. The outcome variable was the presence/absence of Salmonella in the pen fecal samples. The first level was assigned to the pen fecal samples and the second level to the herds. The results showed significant associations between Salmonella occurrence and the factors (p < 0.05): maternity pens versus mating pens (OR = 0.39, 95%CI: 0.24–0.63), feed from external or mixed source versus home source (OR = 2.81, 95%CI: 1.19–6.61), more than 10 animals per pen versus 10 animals per pen (OR = 2.02, 95%CI: 1.19–3.43), North Region versus Alentejo Region (OR = 3.86, 95%CI: 1.08–13.75), rodents control (OR = 0.23, 95%CI: 0.090–0.59), more than 90% of boars homebred or no boars versus more than 90% of boars from an external source (OR = 0.54, 95%CI: 0.3–0.97), semen from another herd versus semen from insemination centers (OR = 4.47, 95%CI: 1.38–14.43) and herds with a size of 170 or more sows (OR = 1.82, 95%CI: 1.04–3.19). This study offers very relevant information for both the Portuguese veterinary authorities and the pig farmers currently developing control programmes for Salmonella. This is the first study providing evidence for semen and boars source as risk factors for Salmonella in breeding pigs.  相似文献   

19.
A PCR based method was developed for the identification of ceftiofur resistance genes (blaCMY-2, blaTEM-1, and ampC) in swine bacterial pathogens. Using this method, the ceftiofur resistant (n = 76) and susceptible (n = 45) strains of Bordetella bronchiseptica, Salmonella spp., Escherichia coli, and Pasteurella multocida were screened for the presence of these three genes. The resistant genes were detected in 70% (blaTEM-1), 68% (blaCMY-2) and 45% (ampC) of the resistant isolates and in 18% (blaTEM-1), 27% (blaCMY-2), and 36% (ampC) of the susceptible isolates. Results obtained in the present study showed widespread distribution of these three resistance genes in ceftiofur-resistant swine pathogens. It was also observed that more pathogens are acquiring these resistance genes.  相似文献   

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