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1.
REASONS FOR PERFORMING STUDY: Bacterial ulcerative keratitis is a common and often vision-threatening problem in horses. Emerging bacterial resistance to commonly used topical antibiotics has been demonstrated. Previous antibiotic use may alter the antimicrobial susceptibility of bacterial isolates. OBJECTIVES: To document aerobic bacterial isolates and associated bacterial susceptibilities from horses with ulcerative keratitis treated at the University of Tennessee between January 1993 and May 2004 and determine whether prior antibiotic therapy affected antimicrobial susceptibility of the isolates. METHODS: Medical records from horses with ulcerative keratitis and positive aerobic bacterial cultures and antimicrobial susceptibility were evaluated. Clinical history regarding antibiotic therapy prior to culture was documented. RESULTS: Fifty-one aerobic bacterial isolates from 43 horses were identified. Streptococcus equi subspecies zooepidemicus was the most commonly isolated organism, accounting for 33.3% of all isolates, followed by Pseudomonas aeruginosa (11.8%), Staphylococcus spp. (11.8%) and Gram-negative nonfermenting rods (7.8 %). No resistance was noted amongst S. equi ssp. zooepidemicus to cephalothin, chloramphenicol or ciprofloxacin. Only 64 % of S. equi ssp. zooepidemicus isolates were sensitive to bacitracin. No resistance was noted among P. aeruginosa to gentamicin, tobramycin or ciprofloxacin. Antibiotic therapy with neomycin-polymixin B-bacitracin prior to presentation and culture was documented in 11/17 horses in which S. equi ssp. zooepidemicus was isolated and in 4/6 horses in which P. aeruginosa was isolated. Three horses received topical corticosteroids prior to culture, of which 2 had polymicrobial infections. CONCLUSIONS: S. equi ssp. zooepidemicus and P. aeruginosa were the most frequently isolated bacterial organisms in equine ulcerative keratitis. No significant trends in aminoglycoside or fluoroquinolone resistance were noted among these organisms. However, the resistance of S. equi ssp. zooepidemicus to bacitracin with common use of this antibiotic suggests that previous antibiotic therapy probably affects antimicrobial resistance. POTENTIAL RELEVANCE: Therapy prior to culture may play an important role in antimicrobial susceptibility of corneal bacterial isolates. Corticosteroid use may increase the risk of polymicrobial infections of corneal ulcers, leading to a worse prognosis. Although significant fluoroquinolone resistance has not been documented in the veterinary literature, these antimicrobials should be reserved for known infected corneal ulcers and not used for prophylaxis. Empirical antibiotic therapy should not only be guided by clinical signs, but also take into consideration previous antimicrobial and corticosteroid therapy.  相似文献   

2.
OBJECTIVES: To analyse antibiotic susceptibility of bacteria associated with ulcerative keratitis in dogs. METHODS: Bacteria isolated from 190 eyes with ulcerative keratitis were identified, and the antibiotic susceptibility of isolates was studied. RESULTS: In total, 258 species of bacteria were isolated from the 190 eyes. Of the isolates, 78 per cent were Gram-positive and 28 per cent were Gram-negative bacteria. The most commonly isolated Gram-positive bacteria in dogs were Staphylococcus spp (49 per cent), Streptococcus spp (7 per cent) and Corynebacterium spp (7 per cent); while Pseudomonas aeruginosa (7.6 per cent) and Escherichia coli (5.8 per cent) were the commonest Gram-negative pathogens. Resistance to commonly used ophthalmic antibiotics was seen in Staphylococcus, Streptococcus, Corynebacterium, Pseudomonas and Escherichia species isolates. CLINICAL SIGNIFICANCE: Isolates from dogs with corneal ulcers in Taiwan may be resistant to several commonly used ophthalmic preparations. Ciprofloxacin showed good action against most isolates, with the notable exception of Streptococcus species. Chloramphenicol or cephalothin had the best in vitro action against the Streptococcus species isolates.  相似文献   

3.
OBJECTIVE: To determine whether antimicrobial resistance patterns of major mastitis pathogens isolated from milk samples from dairy cows have changed over time. DESIGN: Retrospective study. SAMPLE POPULATION: 8905 bacterial isolates obtained from milk samples submitted to the Wisconsin Veterinary Diagnostic Laboratory between January 1994 and June 2001. PROCEDURE: Antimicrobial susceptibility was determined by means of the Kirby-Bauer disk diffusion method. Logistic regression was used to determine whether percentages of isolates resistant to various antimicrobials changed over time. RESULTS: For the gram-positive mastitis pathogens, percentages of isolates resistant to various flactam antimicrobials did not increase over the course of the study. Percentage of Staphylococcus aureus isolates resistant to penicillin decreased from 49 to 30%; percentage of Streptococcus isolates resistant to penicillin decreased from 6 to 1%. Percentage of isolates resistant to erythromycin increased for S aureus, Escherichia coli, Enterobacter spp, Enterococcus spp, and Pasteurella spp. Percentage of isolates resistant to lincomycin increased for S aureus and Staphylococcus spp. Percentage of coagulase-negative Staphylococcus isolates resistant to pirlimycin increased from 6 to 19%. For several pathogens, percentages of isolates resistant to sulfisoxazole and to trimethoprim-sulfamethoxazole decreased. No pathogens had a significant increase in the percentage of isolates resistant to novobiocin-penicillin. CONCLUSIONS AND CLINICAL RELEVANCE: Results did not indicate a trend toward increased antimicrobial resistance among mastitis pathogens isolated from milk samples from dairy cows between 1994 and 2001. Reduced resistance to flactam antimicrobials was identified for several gram-positive mastitis pathogens.  相似文献   

4.
OBJECTIVE: To determine whether resistance to oxacillin and other antimicrobials in 3 Staphylococcus spp commonly isolated from dogs increased from 2001 to 2005. DESIGN: Retrospective case series. SAMPLE POPULATION: 1,772 clinical samples of various types obtained from dogs examined at the University of Tennessee Veterinary Teaching Hospital or at regional veterinary hospitals and submitted to the bacteriology and mycology laboratories associated with the teaching hospital. PROCEDURES: Samples were submitted by attending veterinarians to the bacteriology and mycology laboratories for routine aerobic microbial culture. Identification and antimicrobial susceptibility procedures were performed on all isolates. Susceptibility reports for each antimicrobial and Staphylococcus spp were determined from aggregate electronically archived test results. Oxacillin and multidrug resistance for Staphylococcus intermedius was analyzed by reviewing disk diffusion zone measurements. RESULTS: Oxacillin resistance increased among S. intermedius isolates during the past 5 years, and the increase was associated with multidrug resistance. In 2005, 1 in 5 Staphylococcus spp isolates from canine clinical samples was resistant to oxacillin. The most common staphylococcal species isolated were S. intermedius (n = 37), Staphylococcus schleiferi (21), and Staphylococcus aureus (4), and frequencies of oxacillin resistance in isolates of these species were 15.6%, 46.6%, and 23.5%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Veterinarians should be aware of the potential for empiric drug treatment failures in instances where Staphylococcus spp infections are common (eg, pyoderma). Judicious use of bacterial culture and susceptibility testing is recommended.  相似文献   

5.
This study evaluated the middle ear microbial flora and antimicrobial susceptibility patterns from dogs with otitis media. Antimicrobial susceptibility patterns were obtained on 164 micro-organisms from 107 ears of 82 dogs with otitis media that presented to Louisiana State University over a 12-year period. The most common micro-organisms isolated were Staphylococcus intermedius (26.8%), Pseudomonas aeruginosa (23.2%), β-haemolytic streptococcus (12.8%), Proteus spp. (11.0%) and Staphylococcus epidermidis (8.5%). Antimicrobial susceptibility testing was performed on all isolates employing the disk diffusion method (Kirby-Bauer). Minimum inhibitory concentration (MIC) testing for enrofloxacin and ciprofloxacin was performed on 10 of the 18 P. aeruginosa isolates found to be resistant to enrofloxacin on Kirby-Bauer. Of these isolates, 6 (60%) were susceptible, 1 (10%) was intermediate and 3 (30%) were resistant to enrofloxacin. Eight of these isolates (80%) were susceptible to ciprofloxacin, 1 (10%) showed intermediate susceptibility and 1 (10%) was resistant.  相似文献   

6.
Fluoroquinolone (FQ) antimicrobial agents are used extensively in human and veterinary medicine. Widespread use of any antimicrobial agent can apply selective pressure on populations of bacteria, which may result in an increase in the prevalence of antimicrobial-resistant isolates. Antimicrobial-susceptibility data on bacteria isolated from the canine urinary tract by the University of Missouri-Columbia Veterinary Medical Diagnostic Laboratory, Columbia, MO, were used to determine whether there has been an increase in the prevalence of FQ-resistant bacteria over time. Between January 1992 and December 2001, minimum inhibitory concentrations of either ciprofloxacin (1992-1998) or enrofloxacin (1998-2001) were determined for 1,478 bacterial isolates from the canine urinary tract. The predominant bacterial species isolated were Escherichia coli (547 isolates), Proteus mirabilis (156), and Staphylococcus intermedius (147). In all, there were 13 bacterial species with more than 25 isolates each. A significant increase in the overall proportion of resistant bacterial isolates was documented from 1992 to 2001 (Cochran-Armitage test for trend, P < 0.0001). The same increase in resistant isolates was documented when either ciprofloxacin or enrofloxacin was analyzed separately (P < 0.0001 and P < 0.0002, respectively). No difference was detected in rates of bacterial FQ resistance with regard to the sex of the dog from which the bacteria were isolated. The frequency with which some bacterial species were isolated differed with the sex of the infected dog. Proteus mirabilis was found more often in females (P < 0.0001), whereas beta hemolytic Streptococcus spp., were found more often in males (P = 0.0003). Although the overall efficacy of FQ antimicrobials remained high with greater than 80% of isolates being susceptible, the data demonstrated an increase in the proportion of resistant bacteria isolated from the urinary tract of the dog.  相似文献   

7.
OBJECTIVE: To determine the in vitro fluoroquinolone susceptibility profiles of Pseudomonas aeruginosa isolates from dogs with ulcerative keratitis. Animals-27 dogs with P. aeruginosa-associated ulcerative keratitis. PROCEDURES: P. aeruginosa isolates from dogs with ulcerative keratitis were collected during a 3-year period. Isolates were tested by use of the disk diffusion method for their susceptibility to 7 fluoroquinolones that are available as commercial ophthalmic preparations. The antimicrobials included second- (ciprofloxacin, ofloxacin, norfloxacin, and lomefloxacin), third- (levofloxacin), and fourth-generation (gatifloxacin and moxifloxacin) fluoroquinolones. Isolates were designated as susceptible, intermediate, or resistant to the various antimicrobials. The percentage of susceptible isolates was compared among individual fluoroquinolones and among fluoroquinolone generations. RESULTS: None of the dogs had received topical or systemic fluoroquinolone treatment prior to referral. Twenty-seven P. aeruginosa isolates were collected during the study period. In vitro, bacterial resistance to the tested fluoroquinolones was infrequently identified (24/ 27 isolates were susceptible to all fluoroquinolones evaluated); susceptibility percentages ranged from 88.9% to 100% for individual antimicrobials. There were no significant differences among isolate susceptibilities to the individual antimicrobials or among generations of fluoroquinolones. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of these in vitro data, none of the 7 evaluated fluoroquinolones (individually or collectively by generation) appeared to offer a clinically important advantage in the treatment of P. aeruginosa-associated ulcerative keratitis in dogs. Among the P. aeruginosa isolates collected from dogs with ulcerative keratitis in this study, the likelihood of susceptibility to the fluoroquinolones evaluated was high.  相似文献   

8.
OBJECTIVE: To evaluate the in vitro activity of an ear rinse (ER) containing tromethamine, EDTA, and benzyl alcohol on bacterial pathogens from dogs with otitis. SAMPLE POPULATION: Organisms were collected from ear swab specimens from the external and middle ear and included Staphylococcus spp (n = 11; Staphylococcus intermedius [7] and Staphylococcus spp [4]), Pseudomonas aeruginosa (5), Proteus spp (5), beta-hemolytic streptococcus (11), and 1 control strain of each organism. PROCEDURES: 3 test solutions were evaluated including EDTA, tromethamine, and benzyl alcohol (ER); EDTA and tromethamine (ER without benzyl alcohol [ER - BA]); and purified water. Ten-milliliter aliquots of each test solution were transferred into 36 tubes and inoculated with one of the organisms. Samples were retrieved from each tube at 0, 15, 30, 45, and 60 minutes, transferred to Petri dishes, mixed with soybean-casein digest agar, and incubated. After incubation, plates were examined for growth, and the number of colonies was expressed as CFU per milliliter. RESULTS: ER significantly decreased bacterial growth in vitro of P aeruginosa and beta-hemolytic streptococcal organisms within 15 minutes, Proteus spp within 30 minutes, and Staphylococcus spp within 60 minutes. Comparatively, the presence of benzyl alcohol in ER significantly decreased bacterial growth of beta-hemolytic streptococcus and Proteus spp. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of results of this study, future studies should be performed to evaluate the in vivo efficacy of ER alone as a treatment for otic infections caused by beta-hemolytic streptococcus, P aeruginosa, and Proteus spp and of ER combined with an antimicrobial agent for otic infections caused by Staphylococcus spp.  相似文献   

9.
Objective To document changes in antibiotic resistance of organisms in cases of equine bacterial ulcerative keratitis over a 10‐year time period. Design A retrospective study. Participants Medical records of equine patients with bacterial ulcerative keratitis seen at the University of Florida's VMTH for the years 1991–2000 were reviewed. Materials and methods All cases of equine bacterial ulcerative keratitis for the above mentioned years were examined. Bacterial isolates were identified and subjected to Kirby‐Bauer disc diffusion method sensitivity tests. Antibiotics used in the sensitivity tests included bacitracin, ampicillin, gentamicin, chloramphenicol, polymyxin B, trimethoprim‐sulfa, neomycin, kanamycin, carbenicillin, tobramycin and enrofloxacin. Results A total of 65 bacterial isolates were subjected to sensitivity testing. Of these isolates, Pseudomonas aeruginosa accounted for 14 of the bacterial isolates (22%), Streptococcus equi subspecies zooepidemicus accounted for 13 of the bacterial isolates (20%), and Staphylococcus aureus accounted for four of the isolates (6%). A statistically significant increase in resistance of Pseudomonas aeruginosa isolates to the antibiotics gentamicin and tobramycin was found between the isolates from 1992 to 1998 and those from 1999 to 2000. An increase in resistance of Streptococcus equi subspecies zooepidemicus to gentamicin was found between the isolates from 1993 to 1997 and those from 1998 to 2000. Conclusions Streptococcus equi subspecies zooepidemicus and Pseudomonas aeruginosa were the most common organisms isolated from cases of equine bacterial keratitis referred to the University of Florida's VMTH for the years 1991–2000. There appears to be an increase in resistance of Streptococcus equi subspecies zooepidemicus to gentamicin over the past 10 years. In addition, there is a significant increase in resistance of Pseudomonas aeruginosa to both gentamicin and tobramycin over the same time period.  相似文献   

10.
Objectives: To assess the antibiotic susceptibility of bacteria isolated from corneal ulcers in cats. Methods: A total of 92 cats with infected corneal ulcers were swabbed for bacterial culture and the antibiotic sensitivity of the isolates analysed. Results: Bacteria were isolated from 54 of 92 infected eyes with corneal ulcers and purulent discharge. A total of 59 bacterial isolates were obtained from the 54 ulcers. The ratio of Gram-positive to Gram-negative isolates was approximately 3:1. The most commonly isolated Gram-positive bacteria were Staphylococcus species (51 per cent of all isolates), while Pseudomonas aeruginosa (13.5 per cent of all isolates) was the most common Gram-negative bacteria isolated. The Gram-negative isolates demonstrated a greater incidence of antibiotic resistance than the Gram-positive ones. The most effective antibiotics against the isolates were ciprofloxacin, tobramycin and gentamicin, with erythromycin and lincomycin showing the greatest number of resistant isolates. Clinical Significance: Staphylococcus and Pseudomonas species were the most common Gram-positive and Gram-negative bacteria, respectively, isolated from feline eyes with ulcerative keratitis. The second-generation fluoroquinolone, ciprofloxacin and the aminoglycoside gentamicin were found to be highly effective against the majority of isolates.  相似文献   

11.
The bacterial and fungal flora of 1118 ears of dogs with otitis externa and 100 ears of healthy control dogs were studied in order to isolate the causative agents. The yeast Malassezia pachydermatis (56%) was by far the most common organism in otitic dogs followed by the bacteria Staphylococcus intermedius (23%), Pseudomonas aeruginosa (12%), Proteus spp. (6%) and Streptococcus canis (5%). A statistical analysis of observed results showed that the incidence of these organisms is significant in otitic dogs. Many strains of S.intermedius, P.aeruginosa and Proteus spp. are resistant to antimicrobial agents commonly used to treat otitis externa. Therefore an antimicrobial susceptibility testing was performed using "Cobas Bact" for these bacterias. Furthermore, 80 strains of M.pachydermatis were submitted to identification-kits (API 20 CAUX, API STAPH, Cobas Micro). The observed results showed that an identification with these tests was not possible.  相似文献   

12.
The bacterial and fungal flora of the external ear canal of dogs with otitis externa and of healthy dogs were studied. The most frequently isolated microorganism from otitic ears was Staphylococcus intermedius (58.8%), followed by Malassezia pachydermatis (30.9%), Streptococcus canis (29.9%), Proteus spp. (14.4%) and Escherichia coli (10.3%). A statistical analysis of our results showed that the prevalence of these microorganisms is significant in dogs with otitis externa. Furthermore, the antimicrobial susceptibility patterns of isolated strains were determined. Majority of all bacterial isolates were most susceptible to gentamicin. Malassezia pachydermatis, the most prevalent yeast in this study, showed an excellent level of susceptibility to all antifungal agents tested.  相似文献   

13.
OBJECTIVE: To evaluate a method of aerobic bacteriologic culture of epidermal collarette specimens from dogs with superficial pyoderma and compare results with those for aerobic bacteriologic culture of abdominal skin specimens in healthy dogs. DESIGN: Prospective study. ANIMALS: 22 dogs with epidermal collarettes and 24 healthy dogs. PROCEDURE: Dry sterile cotton swabs were rolled across epidermal collarettes or hairless areas of abdominal skin in healthy dogs and submitted for aerobic bacteriologic culture. Hemolytic colonies of gram-positive-staining cocci were tested for catalase production, and if results were positive, a coagulase test was performed. Colonies with coagulase activity were tested for the ability to ferment mannitol. Antimicrobial susceptibility testing was performed on all Staphylococcus spp that were isolated. RESULTS: S. intermedius was isolated from collarettes in 18 of 22 dogs with superficial pyoderma but not from healthy dogs. Estimated sensitivity and specificity of the culture method were 81.8% and 100%, respectively. There were no significant differences in the ability to culture S. intermedius, the number of S. intermedius isolates without resistance to antimicrobials, and the number of S. intermedius isolates resistant to penicillin G when comparing dogs with superficial pyoderma for the first time and dogs with recurrent pyoderma, dogs that did or did not receive concurrent antimicrobials, and dogs with and without underlying allergic disease. CONCLUSIONS AND CLINICAL RELEVANCE: Bacteriologic culture of epidermal collarette specimens was a simple and reliable method for identification of S. intermedius in dogs with superficial pyoderma, regardless of history of pyoderma or current antimicrobial use.  相似文献   

14.
Bacterial cultures collected over 12 yr from stranded harbor seal (Phoca vitulina) pups and weanlings located in the North Puget Sound and San Juan Islands region of Washington were analyzed retrospectively to determine the most common pathogenic isolates and to describe their antimicrobial resistance patterns. Culture attempts (n = 58) from wounds, umbilici, ears, conjunctiva, nares, oral lesions, and feces yielded 134 pathogenic isolates that represented 17 genera. The majority of isolates were Gram-negative (n = 87; 65%) and of the tested isolates were most susceptible to amikacin (n = 76; 99%) and gentamicin (n = 76; 97%) and least susceptible to ampicillin (n = 76; 26%). Of the Gram-positive isolates tested (n = 29), all were susceptible to amoxicillin/clavulanic acid. The most frequent isolates were Escherichia coli (17%), beta-hemolytic Streptococcus spp. (15%), Enterococcus spp. (11%), and Pseudomonas aeruginosa (11%), with all four exhibiting resistance to more than 50% of the antimicrobials tested. The variety of organisms isolated, the variation in either Gram-negative or Gram-positive predominance, and the multiple drug resistance patterns observed suggest that when treating stranded harbor seals, culture and sensitivity testing are warranted and that antibiotic therapy should be based on results.  相似文献   

15.
Medical records of 131 dogs with external ocular diseases were reviewed. Bacteriologic culture of swab specimens from 151 eyes revealed 100 eyes (66.2%) were considered positive for potentially pathogenic microorganisms. Of 127 species of microorganisms (bacterial and fungal) isolated, 50 (39.3%) were Staphylococcus spp (S intermedius, 17.3%). Streptococcus spp were the next most frequently isolated organism at 32 (25.2%), (Str canis, 16.5%). beta-Hemolytic streptococci (17%) were isolated more frequently than were alpha-hemolytic streptococci (9%), and coagulase-positive staphylococcal species (29%) were isolated almost 3 times as often as were coagulase-negative species (11%). Fungal and yeast organisms were isolated from 4.6% of the eyes. In vitro, most Staphylococcus spp were susceptible to cephalothin, bacitracin, and gentamicin, whereas most Streptococcus spp were susceptible to chloramphenicol, erythromycin, carbenicillin, and cephalothin. Pseudomonas spp were sensitive to tobramycin, gentamicin, and amikacin.  相似文献   

16.
Between January 2002 and June 2007, uropathogens were isolated from 473 of 1557 canine urine samples submitted to Prairie Diagnostic Services from the Western College of Veterinary Medicine Veterinary Teaching Hospital. Culture and susceptibility results were analyzed, retrospectively, to estimate the prevalence of common bacterial uropathogens in dogs with urinary tract infections and to identify changes in antimicrobial resistance. The most common pathogens identified were Escherichia coli, Staphylococcus intermedius, Enterococcus spp., and Proteus spp. Antimicrobial resistance increased during the study period, particularly among recurrent E. coli isolates. Using the formula to help select rational antimicrobial therapy (FRAT), bacterial isolates were most likely to be susceptible to gentamicin, fluoroquinolones, amoxicillin-clavulanic acid, and groups 4 and 5 (third generation) cephalosporins.  相似文献   

17.
Resistance to cephalosporins and/or fluoroquinolones by Staphylococcus intermedius has remained low in Europe, with effective drugs generally available for systemic therapy in pets. However, multiresistant, mecA-positive S. intermedius isolated from dogs and cats is now emerging in Europe. Twelve S. intermedius isolates, highly resistant to at least five antimicrobial classes, were isolated from skin and ear infections in 11 dogs and a cat. The 12 isolates represented 23% of all S. intermedius submissions from one veterinary dermatology referral clinic in northern Germany to veterinary diagnostic laboratories during an 18-month period and resistance included cefalexin, methicillin and enrofloxacin. The animals had been referred to the clinic with recurrent superficial pyoderma, deep pyoderma, pododermatitis or chronic otitis, all unresponsive to systemic beta-lactam-antibiotics or fluoroquinolones. Infection resolved in 10 dogs and the cat on a combination of antimicrobial treatment and correction of underlying causes. Four dogs and a cat required systemic and topical therapy; in six dogs topical antimicrobial therapy alone was successful. Phenotypic and genotypic characteristics of the S. intermedius isolates were determined; species identification was confirmed by polymerase chain detection of thermonuclease genes (nuc) and the presence and expression of the gene conferring resistance to all beta-lactam antibiotics (mecA) were demonstrated in all; based on pulsed-field gel electrophoresis, six were indistinguishable, the others closely or possibly related. The emergence of multiresistant, mecA-positive S. intermedius in Europe is alarming. Zoonotic implications, awareness among veterinary laboratories and strategies for the use of antimicrobials in small animal practice need to be considered.  相似文献   

18.
The susceptibility to antimicrobials of bacterial species most frequently isolated from companion animals in a veterinary teaching diagnostic laboratory was evaluated retrospectively. A significant decrease between 1990-1992 and 2002-2003 was noted in the susceptibility of dog isolates to the following antimicrobials: Escherichia coli to cephalothin (86% to 61%, P < 0.001); E. coli to ampicillin (85% to 67%, P < 0.001); Proteus spp. to ampicillin (92% to 71%, P < 0.01); coagulase-positive staphylococci (Staphylococcus aureus and Staphylococcus intermedius) to enrofloxacin (99% to 95%, P < 0.01). Significantly increased susceptibilities were also noted as follows: coagulase-positive staphylococci to erythromycin (78% to 90%, P < 0.001) and tetracycline (61% to 77%, P < 0.001). Despite a limited number of results available for cats, a significant increase in susceptibility was noted for Pseudomonas spp. to gentamicin (40% to 100%, P < 0.05) and for E. coli to tetracycline (59% to 80%, P < 0.05). Regular updates on the resistance to antimicrobials used in veterinary medicine are required.  相似文献   

19.
BACKGROUND: Fluoroquinolones are often used interchangeably in dogs and cats. HYPOTHESIS: Predicted therapeutic efficacy differs among fluoroquinolones. ANIMALS: Bacterial pathogens isolated from dogs and cats. METHODS: Using microtube-dilution procedures, percent resistance and 2 pharmacodynamic/pharmacokinetic indices (maximum concentration/minimum inhibitory concentration [Cmax/MIC] [target 0.10] and area under curve/minimum inhibitory concentration [AUC/MIC] [target 0.125]) were compared prospectively at low and high doses (mg/kg) for ciprofloxacin (5 and 20), difloxacin (5 and 10), enrofloxacin (including enrofloxacin+ciprofloxacin) (5 and 20), marbofloxacin (2.5 and 5), and orbifloxacin (2.5 and 7.5). Indices were calculated for organisms represented by < or = 15 isolates. RESULTS: Percent resistance for all Gram-negative (n = 180; 20+/-3%; 39+/-5% for Escherichia coli) and Gram-positive isolates (n = 66; 18+/-3%) did not differ among drugs or organisms. The pattern of Cmax/MIC was generally enrofloxacin+ciprofloxacin > or = enrofloxacin or ciprofloxacin > or = marbofloxacin > or = orbifloxacin > or = difloxacin; and for AUIC/ MIC, enrofloxacin+ciprofloxacin > or = marbofloxacin > or = ciprofloxacin > or = enrofloxacin > difloxacin > orbifloxacin. Among susceptible Gram-negative isolates studied (n = 117), targeted Cmax/MIC or AUC/MIC were achieved in 88% of E. coli, 53% of Proteus mirabilis, and 35% of Pseudomonas aeruginosa; and for susceptible Gram-positive isolates studied (n = 49), 53% of Streptotoccus spp. and Staphylococcus intermedius and 27% of Staphylococcus spp. At the high dose, the proportion of isolates for which a target was reached was: ciprofloxacin, enrofloxacin+ciprofloaxin, and marbofloxacin (77%), enrofloxacin (73%), orbifloxacin (51%), and difloxacin (40%); and at the low dose, enrofloxacin+ciprofloxacin and enrofloxacin (43%), ciprofloxacin (40%), marbofloxacin (39%), orbifloxacin (29%), and difloxacin (28%). CONCLUSIONS: E. coli resistance to fluoroquinolones approximated 40%. For susceptible isolates, enrofloxacin, marbofloxacin, and ciprofloxacin more consistently reached indices associated with predicted efficacy, but only at the high dose.  相似文献   

20.
OBJECTIVE: To determine frequency with which Staphylococcus schleiferi could be isolated from dogs with pyoderma and antimicrobial susceptibility patterns of isolates that were obtained. DESIGN: Prospective study. ANIMALS: 54 dogs with a first (n = 14) or recurrent (40) episode of pyoderma. PROCEDURE: Specimens were obtained and submitted for bacterial culture. Isolates were identified as S schleiferi on the basis of growth and biochemical characteristics. Two isolates were submitted for DNA sequencing to confirm identification. Methicillin susceptibility was determined by means of disk diffusion with oxacillin-impregnated disks. RESULTS: 3 of 14 dogs examined because of a first episode of pyoderma and 12 of 40 dogs examined because of a recurrent episode of pyoderma were receiving antimicrobials at the time of specimen collection. Staphylococcus schleiferi was not isolated from any dog with first-time pyoderma but was isolated from 5 dogs with recurrent pyoderma that were not receiving antimicrobials at the time of specimen collection and 10 dogs with recurrent pyoderma that were receiving antimicrobials. Nine isolates were identified as S schleiferi subsp schleiferi, and 6 were identified as S schleiferi subsp coagulans. All S schleiferi subsp schleiferi isolates were resistant to methicillin, but only 2 S schleiferi subsp coagulans isolates were. Two methicillin-resistant isolates were also resistant to fluoroquinolones, and 1 isolate had intermediate susceptibility to fluoroquinolones. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that S schleiferi subsp schleiferi and S schleiferi subsp coagulans may be isolated from dogs with recurrent pyoderma. Although isolates from dogs with pyoderma were frequently resistant to methicillin, multiple drug resistance was uncommon.  相似文献   

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