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Frank Moller Aarestrup - One of the best experts on this subject based on the ideXlab platform.
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world health organization ranking of antimicrobials according to their importance in human medicine a critical step for developing risk management strategies for the use of antimicrobials in Food production Animals
Clinical Infectious Diseases, 2009Co-Authors: Peter Collignon, John H Powers, Tom Chiller, Awa Aidarakane, Frank Moller AarestrupAbstract:The use of antimicrobials in Food Animals creates an important source of antimicrobial-resistant bacteria that can spread to humans through the Food supply. Improved management of the use of antimicrobials in Food Animals, particularly reducing the usage of those that are "critically important" for human medicine, is an important step toward preserving the benefits of antimicrobials for people. The World Health Organization has developed and applied criteria to rank antimicrobials according to their relative importance in human medicine. Clinicians, regulatory agencies, policy makers, and other stakeholders can use this ranking when developing risk management strategies for the use of antimicrobials in Food production Animals. The ranking allows stakeholders to focus risk management efforts on drugs used in Food Animals that are the most important to human medicine and, thus, need to be addressed most urgently, such as fluoroquinolones, macrolides, and third- and fourth-generation cephalosporins.
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world health organization ranking of antimicrobials according to their importance in human medicine a critical step for developing risk management strategies for the use of antimicrobials in Food production Animals
Clinical Infectious Diseases, 2009Co-Authors: Peter Collignon, John H Powers, Tom Chiller, Awa Aidarakane, Frank Moller AarestrupAbstract:The use of antimicrobials in Food Animals creates an important source of antimicrobial-resistant bacteria that can spread to humans through the Food supply. Improved management of the use of antimicrobials in Food Animals, particularly reducing the usage of those that are “critically important” for human medicine, is an important step toward preserving the benefits of antimicrobials for people. The World Health Organization has developed and applied criteria to rank antimicrobials according to their relative importance in human medicine. Clinicians, regulatory agencies, policy makers, and other stakeholders can use this ranking when developing risk management strategies for the use of antimicrobials in Food production Animals. The ranking allows stakeholders to focus risk management efforts on drugs used in Food Animals that are the most important to human medicine and, thus, need to be addressed most urgently, such as fluoroquinolones, macrolides, and third- and fourth-generation cephalosporins. Antimicrobials decrease morbidity and mortality associated with serious and life-threatening infections. Antimicrobial resistance decreases the effectiveness of these drugs, increasing the risk of morbidity and mortality in serious diseases and, thus, compromising human health [1–6]. Antimicrobial resistance is an inevitable consequence of antimicrobial use. Poverty; suboptimal control of the sale, quality, and use of antimicrobials; and poor sewage and water systems are factors that contribute to the emergence and spread of
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resistance in bacteria of the Food chain epidemiology and control strategies
Expert Review of Anti-infective Therapy, 2008Co-Authors: Frank Moller Aarestrup, Henrik Caspar Wegener, Peter CollignonAbstract:Bacteria have evolved multiple mechanisms for the efficient evolution and spread of antimicrobial resistance. Modern Food production facilitates the emergence and spread of resistance through the intensive use of antimicrobial agents and international trade of both Animals and Food products. The main route of transmission between Food Animals and humans is via Food products, although other modes of transmission, such as direct contact and through the environment, also occur. Resistance can spread as resistant pathogens or via transferable genes in different commensal bacteria, making quantification of the transmission difficult. The exposure of humans to antimicrobial resistance from Food Animals can be controlled by either limiting the selective pressure from antimicrobial usage or by limiting the spread of the bacteria/genes. A number of control options are reviewed, including drug licensing, removing financial incentives, banning or restricting the use of certain drugs, altering prescribers behavior, i...
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veterinary drug usage and antimicrobial resistance in bacteria of animal origin
Basic & Clinical Pharmacology & Toxicology, 2005Co-Authors: Frank Moller AarestrupAbstract:In the production of Food Animals, large amounts of antimicrobial agents are used for therapy and prophylaxis of bacterial infections and in feed to promote growth. There are large variations in the amounts of antimicrobial agents used to produce the same amount of meat among the different European countries, which leaves room for considerable reductions in some countries. The emergence of resistant bacteria and resistance genes due to the use of antimicrobial agents are well documented. In Denmark it has been possible to reduce the usage of antimicrobial agents for Food Animals significantly and in general decreases in resistance have followed. Guidelines for prudent use of antimicrobial agents may help to slow down the selection for resistance and should be based on knowledge regarding the normal susceptibility patterns of the causative agents and take into account the potential problems for human health. Current knowledge regarding the occurrence of antimicrobial resistance in Food Animals, the quantitative impact of the use of different antimicrobial agents on selection of resistance and the most appropriate treatment regimes to limit the development of resistance is incomplete. Programmes monitoring the occurrence and development of resistance and consumption of antimicrobial agents are strongly desirable, as is research into the most appropriate ways to use antimicrobial agents in veterinary medicine.
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prevalence of beta lactamases among ampicillin resistant escherichia coli and salmonella isolated from Food Animals in denmark
Microbial Drug Resistance, 2004Co-Authors: Inger Olesen, Henrik Hasman, Frank Moller AarestrupAbstract:The genetic background for β-lactamase-mediated resistance to β-lactam antibiotics was examined by PCR and sequencing in 160 ampicillin-resistant isolates (109 Escherichia coli and 51 Salmonella) obtained from healthy and diseased Food Animals in Denmark. Sequencing revealed three different variants of bla TEM-1, of which bla TEM-1b was the most frequently detected (80 E. coli and 47 Salmonella), followed by bla TEM-1a (eight E. coli, one Salmonella) and bla TEM-1c (seven E. coli). A few isolates were found to express OXA, TEM-30, or PSE β-lactamases. Mutations in the ampC promoter leading to increased production of the AmpC β-lactamase were demonstrated in 11 cefoxitin-resistant or intermediate E. coli isolates. Nine of these isolates did not contain any bla TEM genes, whereas the remaining two did. No genes encoding SHV or extended-spectrum β-lactamases were detected. Two new variants of bla TEM were detected, which have been designated bla TEM-127 and bla TEM-128. In TEM-127, amino acid 158 is substitu...
Peter Collignon - One of the best experts on this subject based on the ideXlab platform.
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world health organization ranking of antimicrobials according to their importance in human medicine a critical step for developing risk management strategies to control antimicrobial resistance from Food animal production
Clinical Infectious Diseases, 2016Co-Authors: Scott A Mcewen, Peter Collignon, Awa Aidarakane, John Conly, Antoine Andremont, Yvonne AgersoAbstract:Antimicrobial use in Food Animals selects for antimicrobial resistance in bacteria, which can spread to people. Reducing use of antimicrobials-particularly those deemed to be critically important for human medicine-in Food production Animals continues to be an important step for preserving the benefits of these antimicrobials for people. The World Health Organization ranking of antimicrobials according to their relative importance in human medicine was recently updated. Antimicrobials considered the highest priority among the critically important antimicrobials were quinolones, third- and fourth-generation cephalosporins, macrolides and ketolides, and glycopeptides. The updated ranking allows stakeholders in the agriculture sector and regulatory agencies to focus risk management efforts on drugs used in Food Animals that are the most important to human medicine. In particular, the current large-scale use of fluoroquinolones, macrolides, and third-generation cephalosporins and any potential use of glycopeptides and carbapenems need to be addressed urgently.
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world health organization ranking of antimicrobials according to their importance in human medicine a critical step for developing risk management strategies for the use of antimicrobials in Food production Animals
Clinical Infectious Diseases, 2009Co-Authors: Peter Collignon, John H Powers, Tom Chiller, Awa Aidarakane, Frank Moller AarestrupAbstract:The use of antimicrobials in Food Animals creates an important source of antimicrobial-resistant bacteria that can spread to humans through the Food supply. Improved management of the use of antimicrobials in Food Animals, particularly reducing the usage of those that are “critically important” for human medicine, is an important step toward preserving the benefits of antimicrobials for people. The World Health Organization has developed and applied criteria to rank antimicrobials according to their relative importance in human medicine. Clinicians, regulatory agencies, policy makers, and other stakeholders can use this ranking when developing risk management strategies for the use of antimicrobials in Food production Animals. The ranking allows stakeholders to focus risk management efforts on drugs used in Food Animals that are the most important to human medicine and, thus, need to be addressed most urgently, such as fluoroquinolones, macrolides, and third- and fourth-generation cephalosporins. Antimicrobials decrease morbidity and mortality associated with serious and life-threatening infections. Antimicrobial resistance decreases the effectiveness of these drugs, increasing the risk of morbidity and mortality in serious diseases and, thus, compromising human health [1–6]. Antimicrobial resistance is an inevitable consequence of antimicrobial use. Poverty; suboptimal control of the sale, quality, and use of antimicrobials; and poor sewage and water systems are factors that contribute to the emergence and spread of
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world health organization ranking of antimicrobials according to their importance in human medicine a critical step for developing risk management strategies for the use of antimicrobials in Food production Animals
Clinical Infectious Diseases, 2009Co-Authors: Peter Collignon, John H Powers, Tom Chiller, Awa Aidarakane, Frank Moller AarestrupAbstract:The use of antimicrobials in Food Animals creates an important source of antimicrobial-resistant bacteria that can spread to humans through the Food supply. Improved management of the use of antimicrobials in Food Animals, particularly reducing the usage of those that are "critically important" for human medicine, is an important step toward preserving the benefits of antimicrobials for people. The World Health Organization has developed and applied criteria to rank antimicrobials according to their relative importance in human medicine. Clinicians, regulatory agencies, policy makers, and other stakeholders can use this ranking when developing risk management strategies for the use of antimicrobials in Food production Animals. The ranking allows stakeholders to focus risk management efforts on drugs used in Food Animals that are the most important to human medicine and, thus, need to be addressed most urgently, such as fluoroquinolones, macrolides, and third- and fourth-generation cephalosporins.
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resistance in bacteria of the Food chain epidemiology and control strategies
Expert Review of Anti-infective Therapy, 2008Co-Authors: Frank Moller Aarestrup, Henrik Caspar Wegener, Peter CollignonAbstract:Bacteria have evolved multiple mechanisms for the efficient evolution and spread of antimicrobial resistance. Modern Food production facilitates the emergence and spread of resistance through the intensive use of antimicrobial agents and international trade of both Animals and Food products. The main route of transmission between Food Animals and humans is via Food products, although other modes of transmission, such as direct contact and through the environment, also occur. Resistance can spread as resistant pathogens or via transferable genes in different commensal bacteria, making quantification of the transmission difficult. The exposure of humans to antimicrobial resistance from Food Animals can be controlled by either limiting the selective pressure from antimicrobial usage or by limiting the spread of the bacteria/genes. A number of control options are reviewed, including drug licensing, removing financial incentives, banning or restricting the use of certain drugs, altering prescribers behavior, i...
Patrick F Mcdermott - One of the best experts on this subject based on the ideXlab platform.
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antimicrobial drug resistance in escherichia coli from humans and Food Animals united states 1950 2002
Emerging Infectious Diseases, 2012Co-Authors: Daniel A Tadesse, Aparna Singh, Sherry Ayers, Shaohua Zhao, Emily Tong, Mary J Bartholomew, Patrick F McdermottAbstract:Antimicrobial drugs have played an indispensable role in decreasing illness and death associated with infectious diseases in Animals and humans. However, selective pressure exerted by antimicrobial drug use also has been the major driving force behind the emergence and spread of drug-resistance traits among pathogenic and commensal bacteria (1). In addition, resistance has developed after advent of every major class of antimicrobial drugs, varying in time from as short as 1 year (penicillin) to >10 years (vancomycin) (2,3). Escherichia coli is usually a commensal bacterium of humans and Animals. Pathogenic variants cause intestinal and extraintestinal infections, including gastroenteritis, urinary tract infection, meningitis, peritonitis, and septicemia (4,5). Therapeutic options vary depending on the type of infection. For example, for urinary tract infections, trimethoprim/sulfamethoxazole and fluoroquinolones are treatments of choice (6), whereas for Shiga toxin–producing E. coli infections, antimicrobial drug therapy is not recommended (7). E. coli is sometimes used as a sentinel for monitoring antimicrobial drug resistance in fecal bacteria because it is found more frequently in a wide range of hosts, acquires resistance easily (8), and is a reliable indicator of resistance in salmonellae (9). Surveillance data show that resistance in E. coli is consistently highest for antimicrobial agents that have been in use the longest time in human and veterinary medicine (10). The past 2 decades have witnessed major increases in emergence and spread of multidrug-resistant bacteria and increasing resistance to newer compounds, such as fluoroquinolones and certain cephalosporins (3). For example, a study of the susceptibility of E. coli isolates recovered from hospitals during a 12-year period (1971–1982) showed no major change in resistance to any of the antimicrobial drugs tested (11). In contrast, a retrospective analysis of E. coli from urine specimens collected from patients during 1997–2007 showed an increasing resistance trend for ciprofloxacin, trimethoprim/sulfamethoxazole, and amoxicillin/clavulanic acid (12). Similarly a 30-year (1979–2009) follow-up study on E. coli in Sweden showed an increasing resistance trend for ampicillin, sulfonamide, trimethoprim, and gentamicin (13). Although studies of farms have shown an association of multidrug-resistant E. coli with chronic antimicrobial drug exposure (14,15), there are few data on temporal trends of antimicrobial drug resistance in Food animal E. coli isolates, particularly those recovered before 1980. Recent data are available in several countries that established resistance monitoring programs during the mid-1990s. In the United States, the National Antimicrobial Resistance Monitoring System (NARMS) was established in 1996 to prospectively monitor changes in antimicrobial drug susceptibilities of zoonotic Foodborne bacteria, including E. coli from retail meats (chicken breast, pork chops, ground beef, ground turkey), and chickens at slaughter. During 2000–2008, NARMS laboratories tested 13,521 E. coli isolates from chickens to determine the MIC to antimicrobial drugs essential in human and veterinary medicine. The resistance trend in chickens observed during this period varied on the basis of the antimicrobial agents. For example, resistance during 2000–2008 decreased slightly for kanamycin (16.1% to 10.2%), streptomycin (77.5% to 54.6%), trimethoprim/sulfamethoxazole (17.2% to 9.1%), and tetracycline (68.4% to 47.4%). Cefoxitin resistance increased from 7.4% in 2000 to 15% in 2006, and ceftriaxone resistance increased from 6.3% to 13.5%. Ciprofloxacin resistance remained low (<1%) during this period. To better understand the historical emergence of resistance since the advent of the antimicrobial drug age, which led to baseline data in the first year of NARMS testing, we assayed E. coli collections from human and animal sources obtained during 1950–2002 for antimicrobial drug susceptibility. This information, when coupled with secular surveillance data, will provide a broader picture of evolution of resistance and lay the groundwork for understanding genetic mechanisms of resistance development and dissemination.
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identification of antimicrobial resistance and class 1 integrons in shiga toxin producing escherichia coli recovered from humans and Food Animals
Journal of Antimicrobial Chemotherapy, 2005Co-Authors: Ruby Singh, David G White, Patrick F Mcdermott, Carl M Schroeder, Jianghong Meng, David D Wagner, Hanchun Yang, Shabbir SimjeeAbstract:Results: Ninety-three (34%) of the isolates were resistant to streptomycin, followed by 89 (32%) to sulfamethoxazole, 83 (30%) to tetracycline, 48 (18%) to ampicillin, 29 (11%) to cefalothin, 22 (8%) to trimethoprim/sulfamethoxazole, 18 (7%) to gentamicin, 13 (5%) to chloramphenicol and 10 (4%) to cefoxitin. Class 1 integrons were detected in 43 (16%) of the 274 isolates. The adenyl acetyltransferase gene, aadA, which confers resistance to streptomycin, was identified in integrons from 41 (95%) of these 43 isolates, and the dfrA12 gene, which confers resistance to trimethoprim, was identified in integrons from eight (19%) of the isolates. The sat1 gene, which confers resistance to streptothricin, an antimicrobial that has never been approved for use in the United States, was identified in integrons from three (7%) of the isolates. Transfer of integrons by conjugation between strains of E. coli resulted in transfer of antimicrobial-resistant phenotypes for ampicillin, chloramphenicol, cefalothin, gentamicin, tetracycline, trimethoprim, sulfamethoxazole and streptomycin. Conclusions: Antimicrobial resistance is common in STEC. Class 1 integrons located on mobile plasmids have facilitated the emergence and dissemination of antimicrobial resistance among STEC in humans and Food Animals.
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characterization of salmonella enterica serotype newport isolated from humans and Food Animals
Journal of Clinical Microbiology, 2003Co-Authors: Shaohua Zhao, S Qaiyumi, Sharon Friedman, Ruby Singh, Steven L Foley, David G White, Patrick F Mcdermott, T Donkar, Carole A Bolin, S MunroAbstract:Salmonella enterica serotype Newport isolates resistant to at least nine antimicrobials (including extended-spectrum cephalosporins), known as serotype Newport MDR-AmpC isolates, have been rapidly emerging as pathogens in both Animals and humans throughout the United States. Resistance to extended-spectrum cephalosporins is associated with clinical failures, including death, in patients with systemic infections. In this study, 87 Salmonella serotype Newport strains were characterized by pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing and examined for the presence of class 1 integrons and blaCMY genes. Thirty-five PFGE patterns were observed with XbaI, and three of these patterns were indistinguishable among isolates from humans and Animals. Fifty-three (60%) Salmonella serotype Newport isolates were identified as serotype Newport MDR-AmpC, including 16 (53%) of 30 human isolates, 27 (93%) of 29 cattle isolates, 7 (70%) of 10 swine isolates, and 3 (30%) of 10 chicken isolates. However, 28 (32%) Salmonella serotype Newport isolates were susceptible to all 16 antimicrobials tested. The blaCMY gene was present in all serotype Newport MDR-AmpC isolates. Furthermore, the plasmid-mediated blaCMY gene was transferable via conjugation to an Escherichia coli strain. The transconjugant showed the MDR-AmpC resistance profile. Thirty-five (40%) of the isolates possessed class 1 integrons. Sequence analyses of the integrons showed that they contained aadA, which confers resistance to streptomycin, or aadA and dhfr, which confer resistance to trimethoprim-sulfamethoxazole. One integron from a swine isolate contained the sat-1 gene, which encodes resistance to streptothricin, an antimicrobial agent that has never been approved for use in the United States. In conclusion, Salmonella serotype Newport MDR-AmpC was commonly identified among Salmonella serotype Newport isolates recovered from humans and Food Animals. These findings support the possibility of transmission of this organism to humans through the Food chain.
Jianhua Liu - One of the best experts on this subject based on the ideXlab platform.
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increasing prevalence of extended spectrum cephalosporin resistant escherichia coli in Food Animals and the diversity of ctx m genotypes during 2003 2012
Veterinary Microbiology, 2014Co-Authors: Lili Rao, Yahong Liu, Xiaojie Chen, Zhenling Zeng, Sheng Chen, Yang Wang, Tong Yang, Jianhua LiuAbstract:Abstract The aim of this study was to investigate the trends and the diversity of CTX-M types of extended-spectrum β-lactamase (ESBL) in Escherichia coli isolated from Food Animals in China over a ten-year period. From 2003 to 2012, 2815 E. coli isolates collected from diseased Animals (chickens, pigs, and waterfowl) were screened for the prevalence of CTX-M genes. CTX-M-positive isolates were tested for their susceptibilities to 10 antimicrobial agents and the clonal relationship of CTX-M-producing E. coli isolates was also assessed. Overall, 677 (20.1%) of the 2815 E. coli isolates carried CTX-M genes. Eighteen different types of CTX-M ESBLs were identified, with CTX-M-14, CTX-M-55, and CTX-M-65 being the most dominant genotypes. The occurrence of CTX-M-producing E. coli increased significantly from 5.7% in 2003–2005 to 35.3% in 2009–2012 ( p E. coli isolates. Most CTX-M-producing strains were also resistant to other classes of antimicrobials. Compared to isolates carrying CTX-M-9 subgroup of ESBLs, isolates carrying CTX-M-1 subgroup ESBLs showed significantly higher resistance rates to ceftazidime, amikacin, and fosfomycin ( p E. coli isolated from Animals overtime in China. The increasing incidence of CTX-M-55 with high hydrolytic activity against ceftazidime and the widely spread co-resistance in CTX-M-producing isolates alarm the serious antimicrobial resistance situation in China and highlight the need for urgent control strategies to limit the dissemination of those resistant genes in China.
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antimicrobial resistance in escherichia coli isolates from Food Animals animal Food products and companion Animals in china
Veterinary Microbiology, 2010Co-Authors: Tao Lei, Yuting Deng, Wei Tian, Xianhui Huang, Yongxue Sun, Yan Sun, Liangzong Huang, Jianzhong Shen, Jianhua LiuAbstract:One thousand and thirty Escherichia coli isolates from Food Animals, Animals-derived Foods, and companion Animals between 2007 and 2008 in Southern China were used to investigate their antimicrobial susceptibility to 14 different antimicrobials by the standard agar dilution method. More than 70% of isolates showed resistance to tetracycline, trimethoprim-sulphamethoxazole, nalidixic acid, and ampicillin. In general, resistance was less frequent in companion animal isolates vs Food Animals isolates, but cephalosporin and amikacin resistance was more frequent in companion animal isolates, 42.6% to 56.2% vs 14.1% to 24.3%, and 28.5% vs 18.8%, respectively, which was most likely due to the common use of these antimicrobials as treatment in pet Animals. Fluroquinolones resistance was high in all animal isolates (>50%). Food products showed lowest resistance among isolates from these three resources. PFGE analysis indicated that a majority of multidrug-resistant E. coli isolates showed unique, unrelated PFGE profiles and were unlikely to be the spread of a specific clone. This study provides useful information about the prevalence of antimicrobial resistance in E. coli isolated from Animals and Food products in China and provided evidence of the linkage of the use of antimicrobials in Animals and its selection of antimicrobial resistance in bacterial isolates. The data from this study further warns the prudent use of antimicrobials in Food and pet Animals to reduce the risks of transmission of antimicrobial resistance zoonotic pathogen to humans.
Shaohua Zhao - One of the best experts on this subject based on the ideXlab platform.
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antimicrobial drug resistance in escherichia coli from humans and Food Animals united states 1950 2002
Emerging Infectious Diseases, 2012Co-Authors: Daniel A Tadesse, Aparna Singh, Sherry Ayers, Shaohua Zhao, Emily Tong, Mary J Bartholomew, Patrick F McdermottAbstract:Antimicrobial drugs have played an indispensable role in decreasing illness and death associated with infectious diseases in Animals and humans. However, selective pressure exerted by antimicrobial drug use also has been the major driving force behind the emergence and spread of drug-resistance traits among pathogenic and commensal bacteria (1). In addition, resistance has developed after advent of every major class of antimicrobial drugs, varying in time from as short as 1 year (penicillin) to >10 years (vancomycin) (2,3). Escherichia coli is usually a commensal bacterium of humans and Animals. Pathogenic variants cause intestinal and extraintestinal infections, including gastroenteritis, urinary tract infection, meningitis, peritonitis, and septicemia (4,5). Therapeutic options vary depending on the type of infection. For example, for urinary tract infections, trimethoprim/sulfamethoxazole and fluoroquinolones are treatments of choice (6), whereas for Shiga toxin–producing E. coli infections, antimicrobial drug therapy is not recommended (7). E. coli is sometimes used as a sentinel for monitoring antimicrobial drug resistance in fecal bacteria because it is found more frequently in a wide range of hosts, acquires resistance easily (8), and is a reliable indicator of resistance in salmonellae (9). Surveillance data show that resistance in E. coli is consistently highest for antimicrobial agents that have been in use the longest time in human and veterinary medicine (10). The past 2 decades have witnessed major increases in emergence and spread of multidrug-resistant bacteria and increasing resistance to newer compounds, such as fluoroquinolones and certain cephalosporins (3). For example, a study of the susceptibility of E. coli isolates recovered from hospitals during a 12-year period (1971–1982) showed no major change in resistance to any of the antimicrobial drugs tested (11). In contrast, a retrospective analysis of E. coli from urine specimens collected from patients during 1997–2007 showed an increasing resistance trend for ciprofloxacin, trimethoprim/sulfamethoxazole, and amoxicillin/clavulanic acid (12). Similarly a 30-year (1979–2009) follow-up study on E. coli in Sweden showed an increasing resistance trend for ampicillin, sulfonamide, trimethoprim, and gentamicin (13). Although studies of farms have shown an association of multidrug-resistant E. coli with chronic antimicrobial drug exposure (14,15), there are few data on temporal trends of antimicrobial drug resistance in Food animal E. coli isolates, particularly those recovered before 1980. Recent data are available in several countries that established resistance monitoring programs during the mid-1990s. In the United States, the National Antimicrobial Resistance Monitoring System (NARMS) was established in 1996 to prospectively monitor changes in antimicrobial drug susceptibilities of zoonotic Foodborne bacteria, including E. coli from retail meats (chicken breast, pork chops, ground beef, ground turkey), and chickens at slaughter. During 2000–2008, NARMS laboratories tested 13,521 E. coli isolates from chickens to determine the MIC to antimicrobial drugs essential in human and veterinary medicine. The resistance trend in chickens observed during this period varied on the basis of the antimicrobial agents. For example, resistance during 2000–2008 decreased slightly for kanamycin (16.1% to 10.2%), streptomycin (77.5% to 54.6%), trimethoprim/sulfamethoxazole (17.2% to 9.1%), and tetracycline (68.4% to 47.4%). Cefoxitin resistance increased from 7.4% in 2000 to 15% in 2006, and ceftriaxone resistance increased from 6.3% to 13.5%. Ciprofloxacin resistance remained low (<1%) during this period. To better understand the historical emergence of resistance since the advent of the antimicrobial drug age, which led to baseline data in the first year of NARMS testing, we assayed E. coli collections from human and animal sources obtained during 1950–2002 for antimicrobial drug susceptibility. This information, when coupled with secular surveillance data, will provide a broader picture of evolution of resistance and lay the groundwork for understanding genetic mechanisms of resistance development and dissemination.
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antimicrobial resistance genes associated with salmonella enterica serovar newport isolates from Food Animals
Antimicrobial Agents and Chemotherapy, 2008Co-Authors: Aaron M Lynne, Shaohua Zhao, Steven L Foley, Bobbie S Rhodesclark, Kimberly A BlivenAbstract:Salmonella enterica serotype Newport is an important cause of salmonellosis, with strains increasingly being resistant to multiple antimicrobial agents. The increase is associated with the acquisition of multiple resistance genes. This study characterizes the genetic basis of resistance of serotype Newport isolates collected from veterinary sources by PCR and DNA sequencing analysis.
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characterization of salmonella enterica serotype newport isolated from humans and Food Animals
Journal of Clinical Microbiology, 2003Co-Authors: Shaohua Zhao, S Qaiyumi, Sharon Friedman, Ruby Singh, Steven L Foley, David G White, Patrick F Mcdermott, T Donkar, Carole A Bolin, S MunroAbstract:Salmonella enterica serotype Newport isolates resistant to at least nine antimicrobials (including extended-spectrum cephalosporins), known as serotype Newport MDR-AmpC isolates, have been rapidly emerging as pathogens in both Animals and humans throughout the United States. Resistance to extended-spectrum cephalosporins is associated with clinical failures, including death, in patients with systemic infections. In this study, 87 Salmonella serotype Newport strains were characterized by pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing and examined for the presence of class 1 integrons and blaCMY genes. Thirty-five PFGE patterns were observed with XbaI, and three of these patterns were indistinguishable among isolates from humans and Animals. Fifty-three (60%) Salmonella serotype Newport isolates were identified as serotype Newport MDR-AmpC, including 16 (53%) of 30 human isolates, 27 (93%) of 29 cattle isolates, 7 (70%) of 10 swine isolates, and 3 (30%) of 10 chicken isolates. However, 28 (32%) Salmonella serotype Newport isolates were susceptible to all 16 antimicrobials tested. The blaCMY gene was present in all serotype Newport MDR-AmpC isolates. Furthermore, the plasmid-mediated blaCMY gene was transferable via conjugation to an Escherichia coli strain. The transconjugant showed the MDR-AmpC resistance profile. Thirty-five (40%) of the isolates possessed class 1 integrons. Sequence analyses of the integrons showed that they contained aadA, which confers resistance to streptomycin, or aadA and dhfr, which confer resistance to trimethoprim-sulfamethoxazole. One integron from a swine isolate contained the sat-1 gene, which encodes resistance to streptothricin, an antimicrobial agent that has never been approved for use in the United States. In conclusion, Salmonella serotype Newport MDR-AmpC was commonly identified among Salmonella serotype Newport isolates recovered from humans and Food Animals. These findings support the possibility of transmission of this organism to humans through the Food chain.
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virulence genes of shiga toxin producing escherichia coli isolated from Food Animals and humans
International Journal of Food Microbiology, 1998Co-Authors: Jianghong Meng, Shaohua Zhao, Michael P DoyleAbstract:The presence of virulence genes, encoding enterohemorrhagic Escherichia coli (EHEC)-hemolysin (EHEC-hlyA), intimin (eae), and Shiga toxins 1 (stx1) and 2 (stx2), in 178 isolates of pathogenic E. coli, was determined using the polymerase chain reaction with primers specific for each virulence gene. The tested organisms were 120 isolates of E. coli O157:H7 from human patients, cattle, sheep and Foods, 16 non-O157:H7 EHEC isolates from patients suffering from hemorrhagic colitis or hemolytic uremic syndrome, 15 non-O157:H7 Shiga toxin-producing E. coli (STEC) isolates from cattle and Foods, 26 isolates of enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC) and enterotoxigenic E. coli (ETEC), and an E. coli K12 strain. Results revealed that all isolates of O157:H7 carried EHEC-hlyA, eae, and one or both stx genes; 15 of the 16 non-O157:H7 EHEC isolates had EHEC-hlyA, but all possessed eae and one or both stx genes; only seven of the 15 non-O157 STEC isolated from cattle and Foods contained both EHEC-hlyA and eae genes. The EPEC, EIEC, ETEC, and the E. coli K12 strain did not carry these virulence genes, except eight EPEC isolates were positive for eae. Results suggest that a combination of EHEC-hlyA and eae genes could serve as markers to differentiate EHEC from less pathogenic STEC, and other pathogenic or non-pathogenic E. coli.