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1.
Brent P. Avery Andrijana Raji? Margaret McFall Richard J. Reid-Smith Anne E. Deckert Rebecca J. Irwin Scott A. McEwen 《Canadian journal of veterinary research》2008,72(2):137-142
Information regarding antimicrobial use in sheep is scarce. In 2001, a scrapie surveillance program was initiated in Alberta that also provided a mechanism for collecting other sheep health data including antimicrobial use information between April 2001 and April 2002. A major objective of this study was to describe antimicrobial use in the Alberta sheep industry. This was done by obtaining qualitative antimicrobial use information from all flocks (n = 212) providing cull ewes to the program using a brief, primarily flock-level, questionnaire. The respondents' flocks represented 13.6% of the total provincial flock in Alberta in 2001. By a substantial amount, the most frequent method of administering antimicrobials was through injection followed by in-feed, oral (liquids, pills, boluses), and in-water routes, respectively. Drug-specific use data were collected for injectable antimicrobials only, with the most commonly used antimicrobial classes being penicillins followed by tetracyclines. Producers rarely treated some or all of their flock with injectable antimicrobials after discovering an individual sick animal. Adult sheep were the most common age group treated with injectable antimicrobials and the most frequent reason for injectable antimicrobial use was mastitis followed by respiratory problems. This study provides some initial insight regarding antimicrobial use in Alberta sheep flocks. However, collection of more drug-specific data (drug type, dose/concentration, duration of treatment) for noninjectable routes of administration should be conducted in future studies. Assessing antimicrobial use in other sectors of the Alberta sheep industry (feedlots) and other provinces across Canada would also be beneficial. 相似文献
2.
Antimicrobial use through feed, water, and injection in 20 swine farms in Alberta and Saskatchewan 
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下载免费PDF全文 Leigh B. Rosengren Cheryl L. Waldner Richard J. Reid-Smith John C.S. Harding Sheryl P. Gow Wendy L. Wilkins 《Canadian journal of veterinary research》2008,72(2):143-150
Antimicrobial resistance (AMR) is an emerging animal welfare and public health issue linked to antimicrobial use (AMU) in livestock. This study was conducted in 2004 on 20 swine farms in Alberta and Saskatchewan. On-farm records and questionnaires were used to retrospectively describe the antimicrobial exposures of pigs through feed, water, and injection. Antimicrobial use in all production categories was described over 12 months. On-farm records and questionnaires provided sufficient data to describe antimicrobial exposure rates through feed and water. In contrast, on-farm records did not supply sufficient data to describe parenteral antimicrobial exposure rates. Records lacked data on the number of exposures per treatment, therefore parenteral AMU was described as an exposure incidence. Parenteral exposure records were often unavailable for pigs less than 22 kg, in which case questionnaires were used. The incidence of parenteral AMU was significantly higher in herds reporting exposure by questionnaire compared with existing records, suggesting that on-farm records did not reliably describe parenteral AMU. However, because antimicrobial exposures in feed and water were markedly more common than through injection, it was concluded that existing on-farm data would be a valuable resource for investigating AMU and AMR in pigs. 相似文献
3.
L.E. Redding F. Cubas-Delgado M.D. Sammel G. Smith D.T. Galligan M.Z. Levy S. Hennessy 《Preventive veterinary medicine》2014
Very little is known about the use of antibiotics on small dairy farms in lower/middle-income countries. The use of these drugs can have profound impacts on animal health, farmer income and public health. A survey of 156 farmers was conducted in Cajamarca, a major dairy-producing center in the highlands of Peru characterized by small farms (<15 cows) to assess patterns and determinants of antibiotic use and farmers’ knowledge of antibiotics. The reported incidence of disease on these farms was relatively low (0.571 episodes of disease per cow-year), but more than 83% of the reported episodes were treated with antibiotics. The most commonly used antibiotics were oxytetracycline, penicillin and trimethoprim-sulfamethoxazole drugs; antiparasitic drugs were also used to treat what were likely bacterial infections. An increased incidence of treated disease was significantly associated with smaller farm size, lower farmer income, the previous use of the Californian Mastitis test on the farm and antibiotic knowledge. Farmers’ knowledge of antibiotics was assessed with a series of questions on antibiotics, resulting in a “knowledge score”. Increased knowledge was significantly associated with the use of antibiotics for preventative reasons, the purchase of antibiotics from feed-stores, the experience of complications in animals after having administered antibiotics, the number of workers on the farm and the educational level of the farmer. Overall, antibiotics appeared to be used infrequently, most likely because therapeutic interventions were sought only when the animal had reached an advanced stage of clinical disease. Few farmers were able to define an antibiotic, but many farmers understood that the use of antibiotics carried inherent risks to their animals and potentially to the consumers of dairy products from treated animals. The results of this study are useful for understanding the patterns of antibiotic use and associated management, demographic and knowledge factors of farmers on small dairy farms in rural Peru. 相似文献
4.
Moon CS Berke O Avery BP McEwen SA Reid-Smith RJ Scott L Menzies P 《The Canadian veterinary journal. La revue veterinaire canadienne》2010,51(12):1373-1378
This study examined characteristics of the use of drugs, especially antimicrobials, on Ontario sheep farms. Forty-nine sheep farms participated in a 12-month prospective study. Producers documented treatment events during the study period and drug use data from the records were summarized. The most frequently used drugs of the 15 drug categories used by producers belonged to the following categories: antimicrobial (40.7%, n=2710), vitamin/mineral (12.0%), and biological (11.1%). Short-acting penicillin (27.2%, n=1103), long-acting oxytetracycline (22.9%), and long-acting penicillin (21.9%) were the most frequently used antimicrobials. The drugs that were used most frequently on sheep farms were antimicrobials, of which 93% of treatments were extra-label. Extensive extra-label drug use may be the result of the limited number of drugs that are approved in Canada for use in sheep. 相似文献
5.
Antimicrobial resistance of Salmonella isolated from finishing swine and the environment of 60 Alberta swine farms 总被引：5，自引：0，他引：5
Rajić A McFall ME Deckert AE Reid-Smith R Manninen K Poppe C Dewey CE McEwen SA 《Veterinary microbiology》2004,104(3-4):189-196
The study objective was to describe and evaluate antimicrobial resistance profiles in Salmonella isolated from Alberta swine finishing farms. Salmonella isolates (n = 322) were obtained from 192 fecal and 84 environmental samples of the 60 Salmonella-positive swine finishing farms. Isolates were classified susceptible, intermediate or resistant based on NCCLS guidelines. More than half of the isolates (53.4%) were susceptible to all of the 18 antimicrobials in the testing panel. No resistance was observed to amikacin, amoxicillin/clavulanic acid, cefoxitin, ceftiofur, ceftriaxone, cephalothin, ciprofloxacin, imipenem or nalidixic acid. Less than 1% of isolates were resistant to apramycin, gentamicin and trimethoprim/sulfamethoxazole. Higher frequencies of resistance were observed for chloramphenicol (4.7%), ampicillin (7.8%), kanamycin (11.8%), sulfamethoxazole (21.1%), streptomycin (25.5%) and tetracycline (38.8%). Eleven Salmonella serovars had isolates with resistance to > or =3 antimicrobials. The most frequently resistant serovar was Salmonella Derby, with 27 (38.0%) isolates resistant to > or =3 antimicrobials, including resistance to five and six antimicrobials. An absence of resistance to cephalosporins and fluoroquniolones and a low proportion of isolates resistant to amikacin, amoxicillin/clavulanic acid, apramycin, gentamicin and trimethoprim/sulfamethoxazole are encouraging findings from public health and animal health perspectives. Frequent resistance observed for ampicillin, kanamycin, sulfamethoxazole, streptomycin and tetracycline, antimicrobials commonly used in veterinary medicine for decades, indicates an urgent need to utilize these antimicrobials more prudently if their benefits are to be preserved. 相似文献
6.
Rajic A Keenliside J McFall ME Deckert AE Muckle AC O'Connor BP Manninen K Dewey CE McEwen SA 《Veterinary microbiology》2005,105(1):47-56
The aim of this study was to determine the farm prevalence of Salmonella in 90 Alberta finishing swine farms over a 5-month period, to evaluate Salmonella distribution in the farm environment and to describe Salmonella serovar diversity on these farms. Ten veterinary practitioners selected 90 Alberta swine farms based on an annual production of > or =2000 market pigs per farm and the willingness of the producers to participate in the study. Between May and September 2000, twenty samples were collected from finishing swine and the environment of each farm. The annual production of selected farms represented approximately 25% of the market swine production in Alberta. Participating farms were geographically representative of major swine production areas in Alberta. Sixty (66.7%) farms had at least one Salmonella-positive sample, with confidence interval (CI) of 57.1-77.2%. Salmonella were detected in 14.3% of fecal and 20.1% of environmental samples. The number of Salmonella-positive samples per farm ranged from 1 to 19. Among environmental samples, Salmonella were most frequently recovered from boots (38.6%) and the main drain (31.8%). Twenty-two serovars were detected on the 60 Salmonella-positive farms. Serovars Typhimurium (78 isolates), Derby (71 isolates) and Infantis (47 isolates) were the most common. A single serovar was detected on 58 farms, while 2, 3 and >3 serovars were detected on 15, 10 and 7 farms, respectively. The Salmonella farm status changed frequently over the 5-month period indicating the dynamic nature of Salmonella infections on these farms. 相似文献
7.
Drug residues in food animals 总被引：5，自引：0，他引：5
W R Van Dresser J R Wilcke 《Journal of the American Veterinary Medical Association》1989,194(12):1700-1710
A total of 292 field investigative reports of drug residues in food animals for 1983 to 1988 were analyzed. The investigations had been conducted by the Food and Drug Administration (FDA) and the Virginia State Veterinarian's Office, in cooperation with the Center for Veterinary Medicine of the FDA, to trace residues reported by the USDA Food Safety and Inspection Service to the source of the animal and the administration of the drug. The analysis disclosed the following. (1) Antibiotic residues were most often associated with streptomycin, penicillin, oxytetracycline, and neomycin. Sulfamethazine was, by far, the most frequently cited sulfonamide. (2) Residues are being found predominantly in cows, veal calves, and market hogs (barrows and gilts). (3) The cause of drug residue most frequently cited by the field investigators was failure to observe the withholding time for the drug. Almost half of these investigations revealed that the individual responsible for the sale of the animal did not know the proper withholding time for the drug. Failure to maintain adequate records was also a contributing factor. (4) The producer was considered to be the responsible party in over 80% of the cases for which responsibility was determined. (5) Residues associated with injectable drugs were investigated most frequently. Long-acting and sustained-release products were most often associated with penicillin and oxytetracycline residues. (6) The 2 most common sources of purchase for the drugs involved in the investigations were the feed/farm supply store and the veterinarian. (7) Unapproved drug use was not a major cause of residues. 相似文献
8.
Na lampang K Chongsuvivatwong V Kitikoon V 《Tropical animal health and production》2007,39(5):355-361
The study was conducted on antibiotics use and determinant of use on 101 broiler farms in Songkhla province, Thailand. Ninety-six farms used the broiler production system under contracting companies and 5 farms were independently operated. All of the farms used antibiotics for disease prevention. Twenty agents in 9 classes of antibiotics were used; the most commonly used ones were enrofloxacin, amoxicillin, doxycycline, colistine and roxithromycin. There were 33 patterns of antibiotics use, the most frequently used being the combination of amoxicillin-enrofloxacin (21.18%). Cluster analysis suggested that the variation in antibiotic usage is mostly under the influence of the companies. Regulation of antibiotics use thus should focus on the company level. 相似文献
9.
Karina L. Goularte Flávia L. S. Voloski Josiara F. M. Redú Carlos E. R. Ferreira Arnaldo D. Vieira Eduarda H. Duval Rafael G. Mondadori Thomaz Lucia Jr 《Reproduction in domestic animals》2020,55(3):318-324
Many microorganisms from various sources may be present in ejaculates of bulls. This study identified and isolated bacteria from bull sperm samples in a commercial stud and evaluated their resistance to antibiotics. The number of colony-forming units was determined in semen samples collected at distinct steps during freezing and thawing. The minimum inhibitory concentration and the minimum bactericidal concentration were determined for four antibiotics commonly used in commercial studs. A total of 135 microorganisms from 25 genera were isolated. After a sensitivity test, all evaluated microorganisms (n = 55) were resistant to penicillin and most of them were resistant to tylosin and lincomycin (n = 54). Resistance to all tested antibiotics was observed in 22% of all isolates, whereas only 3.9% of the isolates were inhibited by the tested antibiotics at the concentrations recommended by the international legislation. As the isolated microorganisms presented high resistance to frequently used antibiotics, sensitivity tests should be periodically conducted in commercial bull semen studs to prevent the use of contaminated semen in artificial insemination. 相似文献
10.
Eltayb A Barakat S Marrone G Shaddad S Stålsby Lundborg C 《Zoonoses and public health》2012,59(5):330-338
Antibiotic resistance is a major emerging global public health threat. Farmers in the Khartoum state are believed to misuse antibiotics in animal farming leading to daily exposure to resistant bacteria and antibiotic residues. Hence, farmers are at potential risk exposure to bacteria, zoonotic infection and toxicity. We hypothesized that farmers' misuse of antibiotics could be due to their ignorance of the importance of optimal use of antibiotics, the potential health hazards and the economical waste associated with antibiotic misuse practices. In the present study, we investigated knowledge and practices among farmers regarding antibiotic use and resistance. For this purpose, a cross-sectional study was conducted in Khartoum state where data were collected from 81 farmers using structured interviews. Data were analysed both quantitatively and qualitatively. Fifty-two per cent of farmers were uneducated or had studied for < 6 years. The majority reported antibiotic use for treatment and prevention while only 5% stated use for growth promotion. Antibiotic group treatment for both sick and healthy animals was commonly practiced among most farmers. The most commonly used group of antibiotics was the quinolones, which was reported by one-third. Only 30% of the farmers had heard of antibiotic resistance and provided their definition. Almost half were not aware of the commonly transferred zoonotic infections between humans and animals. The farmers consume 1-2 meals/day from their own farm products. A significant association between low education, poor knowledge of farmers on antibiotic use, antibiotic resistance and zoonotic infections was found. This association may play a vital role in the present practiced misuse of antibiotics. Our findings on farmers' practices could be used as baseline information in defining the gaps related to antibiotic use and resistance in animal farming in Sudan. It can thus serve as a foundation for future interventions. 相似文献
11.
J O Ikheloa M B Aruna G O Ayoade 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1992,45(2):135-137
Diarrhoeic faecal samples from 210 humans and 192 swine were screened for Yersinia enterocolitica in 1990. Ten and 8 Y. enterocolitica strains were isolated from pig and man, respectively. The isolates were found to belong to Wauter's biotypes 1, 2, 3 and 4. Biotype 2 was isolated mainly from human stool samples. Biotype 3 was found only in swine while biotypes 1 and 4 were isolated from both man and swine. All the 18 strains showed varying degrees of sensitivity to antibiotics used in this investigation. The organisms were consistent in their resistance to ampicillin and penicillin. 相似文献
12.
Residue persistence in sheep milk following antibiotic therapy 总被引：2，自引：0，他引：2
Molina A Molina MP Althaus RL Gallego L 《Veterinary journal (London, England : 1997)》2003,165(1):84-89
Drug residues in milk supplies may have public health implications and can interfere in the manufacture of dairy products, such as cheese. In Spain, most ewe milk production is destined for cheese making, often using raw milk. This study analyses the main factors influencing antibiotic depletion time in lactating dairy sheep. 42, Manchega ewes were distributed into three groups, each receiving a different treatment (cephalexin intramammary infusion, penicillin G intramuscular, and oxytetracycline intravenous injections). During and after the recommended withdrawal period, milk samples were taken at each milking. A microbiological inhibition test (Brilliant Black Reduction, BRT) was used to screen all samples and antibiotic withholding times were established using a logistic regression model. The response to the BRT method in milk from individual ewes treated showed that the effect of the milking order was significant (P<0.001) with the three antibiotics. However the only influence on milk yield was with the intramammary treatment (P<0.005). The BRT method was found to be very sensitive, particularly to the two beta-lactamic antibiotics. 相似文献
13.
Carolee A. Carson Richard Reid-Smith Rebecca J. Irwin Wayne S. Martin Scott A. McEwen 《Canadian journal of veterinary research》2008,72(2):109-118
Understanding risk factors for antimicrobial resistance requires knowledge of antimicrobial selection pressure. The objectives of this research were to develop methodology for collecting quantitative antimicrobial use information from beef producers in Ontario, to document the types and quantities of antimicrobials reported (for a minimum of 12 mo), and to compare 2 metrics for injectable use reporting. Twenty-four volunteer beef producers were asked to complete a questionnaire, document drug use in a treatment diary, and retain empty medication containers. For injectable antimicrobials, producers recorded approximately 60% of the total use in the treatment diaries; oxytetracycline, penicillin, macrolides, florfenicol, and spectinomycin were used in the greatest quantities. Based on estimated weights of active ingredients (calculated according to number of animals exposed, duration, and average dose per day) the antimicrobials most commonly used in feed were monensin, tylosin, lasalocid, and tetracyclines. The antimicrobials most commonly used in water were lincomycin-spectinomycin, chlortetracycline, and oxytetracycline. Based on estimated weights and measured quantities, < 1% of antimicrobials used were in the Canadian category of highest importance to human medicine. A comparison of animal daily dosages to kilograms of active ingredient demonstrated that the relative ranking of use of antimicrobials varied with the chosen metric, and that further investigation into the best measure in relation to antimicrobial resistance is warranted. 相似文献
14.
Uterine microbiology and antimicrobial susceptibility was investigated in 239 mares with fertility problems in a prospective study in Sweden. Uterine swab samples were collected with double guarded swabs and transported overnight before being cultured. The Minimum Inhibitory Concentrations (MIC) was determined for a panel of antimicrobials. From 152 of the 239 mares at least one bacterial species was isolated, most frequently E. coli (104 isolates), beta-haemolytic streptococci (31) and fungi (16). beta-haemolytic streptococci were more frequently (p < 0.01) associated with clinical endometritis than with repeat breeding. The opposite was true for E. coli (p < 0.01). Among beta-haemolytic streptococcal isolates some resistance was noted for 4 of 11 tested antibiotics, however, all isolates were susceptible to the widely used penicillin G. Among E. coli isolates enrofloxacin was the only of the 10 tested antibiotics for which no resistance was noted. Resistance was most commonly noted to cephalothin (39% of the isolates), streptomycin (22%), trimethoprim/sulphamethoxazole (15%) and ampicillin (11%). In conclusion, we show that both E.coli and beta-haemolytic streptococci are frequently associated with fertility problems in mares and that antimicrobial resistance is a common feature of E. coli but also recognised for beta-haemolytic streptococcal uterine isolates. 相似文献
15.
为确定导致江苏某奶牛场蹄部感染的病原,采集发病奶牛蹄部感染病灶的病料进行细菌分离培养,使用MALDI Biotyper微生物快速鉴定系统进行细菌鉴定,并对分离菌株进行药物敏感性试验。结果显示,病灶中的分离株为污蝇解壳杆菌(Wohlfahrtiimonas chitiniclastica),血平板上呈β型溶血。药敏试验结果显示,该菌株对阿莫西林钠-克拉维酸钾、多西环素、四环素、头孢氨苄、链霉素、青霉素和复方新诺明7种抗生素耐药,对多黏菌素、丁胺卡那、庆大霉素、环丙沙星、克林霉素5种抗生素敏感。污蝇解壳杆菌作为一种人畜共患的病原菌,其在奶牛蹄部的感染需要引起奶牛场的关注,同时其耐药性增加更具有公共卫生学意义。该病原的分离鉴定和药敏试验为指导奶牛养殖场合理用药和提高公共卫生管理具有重要意义。 相似文献
16.
广东地区动物源性大肠杆菌的分离及药敏分析 总被引：1，自引：0，他引：1
由广东多个地区猪及禽类养殖场采集疑似大肠杆菌病病料,分离出猪源及禽源大肠杆菌共71株。血清型鉴定实验确定52株的血清型,其中猪源大肠杆菌28株,优势血清型为O101及O157,这两种血清型分别占25％与17．9％;禽源大肠杆菌24株,优势血清型为O119,占62．4％。选用10种抗生素试纸进行药敏试验（庆大霉素、复方新诺明、氟哌酸、红霉素、羧苄青霉素、头孢氨苄、青霉素G、氯霉素、氨苄青霉素、丁胺卡那霉素）,结果表明实验菌株耐药性程度较高。 相似文献
17.
Klimiene I Ruzauskas M Spakauskas V Matusevicius A Mockeliūnas R Pereckiene A Butrimaite-Ambrozeviciene C Virgailis M 《Polish journal of veterinary sciences》2011,14(3):467-472
The aim of the study was to isolate gram-positive cocci from cows with mastitis and to determine their resistance to beta-lactamic antibiotics. Eight hundred and nine strains were isolated and identified as staphylococci (n=516), streptococci (n=199) and enterococci (n=94) from sub-clinical and clinical cases of bovine mastitis in Lithuania. The most common causative agents of udder disease included: S. epidermidis (n=176), S. aureus (n=176), S. agalactiae (n=134), S. hyicus (136) and E. hirae (n=68). Isolates were analysed for antimicrobial resistance to penicillin, ampicillin, amoxicillin, cephalothin, cephalexin, amoxicillin + clavulanate. The susceptibility patterns were analysed using the agar disk diffusion method. S. aureus showed the highest level of resistance to amoxicillin (81.3%), penicillin (76.7%) and ampicillin (78.4%). The corresponding values for CNS strains were 59.7%, 59.7% and 50.6% against penicillin, ampicillin and amoxicillin respectively. Streptococci were the most frequently resistant to amoxicillin (29.3%), and enterococci to penicillin (27%), amoxicillin (27.5%) and amoxicillin/clavulanic acid (23.8%). The resistance of all tested mastitis pathogens to aminopenicillins and penicillin highly correlated (r=0.83). Compared with other antibiotics, amoxicillin and clavulanic acid combination tended to be more effective (p<0.05) against all tested bacteria in vitro. However, S. aureus, in 38.1% of cases, was resistant to this combination of antimicrobials. This study demonstrates that S. epidermidis, S. aureus, S. hyicus, S. agalactiae and E. hirae remain the most frequent mastitis causative agents on Lithuanian cattle farms. The highest resistance in vitro to penicillins was demonstrated by S. aureus, S. hyicus and S. intermedius. Resistance to cephalosporins remains low, irrespective of bacterial species of gram-positive cocci. 相似文献
18.
《畜牧与生物技术杂志(英文版)》2016,(1)
With the widespread ban on the use of antibiotics in swine feed,alternative measures need to be sought to maintain swine health and performance.Antimicrobial peptides(AMPs) are part of the nonspecific defense system and are natural antibiotics produced by plants,insects,mammalians,and micro-organisms as well as by chemical synthesis.Due to their broad microbicidal activity against various fungi,bacteria and enveloped viruses,AMPs are a potential alternative to conventional antibiotics for use in swine production.This review focuses on the structure and mechanism of action of AMPs,as well as their effects on performance,immune function and intestinal health in pigs.The aim is to provide support for the application of AMPs as feed additives replacing antibiotics in swine nutrition. 相似文献
19.
[目的] 了解泰州市某奶牛场乳房炎中金黄色葡萄球菌（Staphylococcus aureus ）感染情况及其对常用药物的敏感性。[方法] 试验选用Baird-Parker培养基分离、生化鉴定、PCR检测等方法,对采集的9份奶牛乳房炎奶样进行分离鉴定和药敏试验。[结果] 共分离到6株葡萄球菌,进一步通过凝固酶试验和16S rDNA测序等方法鉴定其中3株为金黄色葡萄球菌。药敏试验结果显示,3株金黄色葡萄球菌对青霉素G均耐药,2株对四环素耐药,2株对红霉素和苯唑西林表现为中介。[结论] 该次分离的金黄色葡萄球菌主要对青霉素G和四环素耐药,对其他常用抗生素表现为敏感。 相似文献
20.
Multiple drug resistance in Pasteurella multocida and Pasteurella haemolytica from cattle and swine. 总被引：10，自引：0，他引：10
The results of antimicrobial susceptibility testing on 262 strains of Pasteurella multocida and 141 strains of Pasteurella haemolytica isolated from cattle and swine from 1971 to 1974 were analyzed for patterns of resistance to streptomycin, penicillin, tetracycline, and chloramphenicol, using a modified Kirby-Bauer procedure. Resistance was recorded for 80.5% of the isolants of P multocida and 92.2% of those of P haemolytica. Resistance to streptomycin was most frequent, followed by resistance to penicillin and tetracycline. Most cultures of P multocida and P haemolytica were susceptible to chloramphenicol. There were 9 patterns of resistance with the aforementioned antibiotics. The combinations, streptomycin and penicillin and streptomycin and tetracycline, each accounted for approximately 10% of the resistance patterns of P multocida. Approximately half of the 14 isolants of P haemolytica were resistant to the combination of streptomycin, penicillin, and tetracycline. These observations underscore the need for antimicrobial susceptibility testing of clinical isolants of P multocida and P haemolytica. 相似文献