RESUMO
OBJECTIVES: The aim of this study was to identify and analyse the first integrative and conjugative element (ICE) from Mannheimia haemolytica, the major bacterial component of the bovine respiratory disease (BRD) complex. METHODS: The novel ICEMh1 was discovered in the whole-genome sequence of M. haemolytica 42548 by sequence analysis and comparative genomics. Transfer of ICEMh1 was confirmed by conjugation into Pasteurella multocida recipient cells. RESULTS: ICEMh1 has a size of 92,345 bp and harbours 107 genes. It integrates into a chromosomal tRNA(Leu) copy. Within two resistance gene regions of â¼ 7.4 and 3.3 kb, ICEMh1 harbours five genes, which confer resistance to streptomycin (strA and strB), kanamycin/neomycin (aphA1), tetracycline [tetR-tet(H)] and sulphonamides (sul2). ICEMh1 is related to the recently described ICEPmu1 and both ICEs seem to have evolved from a common ancestor. A region of ICEMh1 that is absent in ICEPmu1 was found in putative ICE regions of other M. haemolytica genomes, suggesting a recombination event between two ICEs. ICEMh1 transfers to P. multocida by conjugation, in which it also uses a tRNA(Leu) as the integration site. PCR assays and susceptibility testing confirmed the presence and activity of the ICEMh1-associated resistance genes in the P. multocida recipient. CONCLUSIONS: These findings showed that ICEs, with structurally variable resistance gene regions, are present in BRD-associated Pasteurellaceae, can easily spread across genus borders and enable the acquisition of multidrug resistance via a single horizontal gene transfer event. This poses a threat to efficient antimicrobial chemotherapy of BRD-associated bacterial pathogens.
Assuntos
Sequências Repetitivas Dispersas , Mannheimia haemolytica/genética , Conjugação Genética , DNA Bacteriano/química , DNA Bacteriano/genética , Farmacorresistência Bacteriana , Ordem dos Genes , Transferência Genética Horizontal , Genes Bacterianos , Genoma Bacteriano , Dados de Sequência Molecular , Pasteurella multocida , Análise de Sequência de DNARESUMO
During a survey of fresh chicken and turkey meat as well as chicken and turkey meat products for the presence of methicillin-resistant Staphylococcus aureus (MRSA) isolates in Germany, 32 (37.2%) of 86 samples were MRSA positive. Twenty-eight of these MRSA isolates belonged to clonal complex 398 (CC398), which is widespread among food-producing animals. These CC398 isolates carried SCCmec elements of type IV or V and exhibited spa type t011, t034, t899, t2346 or t6574 and either the known dru types dt2b, dt6j, dt10a, dt10q, dt11a, dt11v, and dt11ab or the novel dru types dt6m, dt10as, and dt10at. In addition, two MRSA sequence type 9 (ST9) isolates with a type IV SCCmec cassette, spa type t1430, and dru type dt10a as well as single MRSA ST5 and ST1791 isolates with a type III SCCmec cassette, spa type t002, and dru type dt9v were identified. All but two isolates were classified as multiresistant. A wide variety of resistance phenotypes and genotypes were detected. All isolates were negative for the major virulence factors, such as Panton-Valentine leukocidin, toxic shock syndrome toxin 1, or exfoliative toxins. In contrast to the MRSA CC398 isolates, the four ST9, ST5, or ST1791 isolates harbored the egc gene cluster for enterotoxin G, I, M, N, O, and U genes. Although the relevance of contamination of fresh poultry meat or poultry products with MRSA is currently unclear, the presence of multiresistant and, in part, enterotoxigenic MRSA emphasizes the need for further studies to elucidate possible health hazards for consumers.
Assuntos
Carne/microbiologia , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Galinhas , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla , Enterotoxinas/genética , Exfoliatinas/genética , Exotoxinas/genética , Genes Bacterianos , Alemanha , Leucocidinas/genética , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Tipagem Molecular , Família Multigênica , Proteínas de Ligação às Penicilinas , Proteína Estafilocócica A/genética , Superantígenos/genética , Turquia , Fatores de Virulência/genéticaAssuntos
Antibacterianos/farmacologia , Doenças dos Bovinos/microbiologia , Macrolídeos/farmacologia , Mannheimia haemolytica/efeitos dos fármacos , Infecções por Pasteurella/veterinária , Pasteurella multocida/efeitos dos fármacos , Animais , Bovinos , Genes Bacterianos , Mannheimia haemolytica/genética , Mannheimia haemolytica/isolamento & purificação , Testes de Sensibilidade Microbiana , Infecções por Pasteurella/microbiologia , Pasteurella multocida/genética , Pasteurella multocida/isolamento & purificaçãoRESUMO
During the last decade, antimicrobial resistance in bacteria from food-producing animals has become a major research topic. In this review, different emerging resistance properties related to bacteria of food-producing animals are highlighted. These include: extended-spectrum ß-lactamase-producing Enterobacteriaceae; carbapenemase-producing bacteria; bovine respiratory tract pathogens, such as Pasteurella multocida and Mannheimia haemolytica, which harbor the multiresistance mediating integrative and conjugative element ICEPmu1; Gram-positive and Gram-negative bacteria that carry the multiresistance gene cfr; and the occurrence of numerous novel antimicrobial resistance genes in livestock-associated methicillin-resistant Staphylococcus aureus. The emergence of the aforementioned resistance properties is mainly based on the exchange of mobile genetic elements that carry the respective resistance genes.
Assuntos
Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla , Gado/microbiologia , Animais , Bactérias/genética , Proteínas de Bactérias/genética , Bovinos , Farmacorresistência Bacteriana Múltipla/genética , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/genética , Transferência Genética Horizontal , Humanos , Sequências Repetitivas Dispersas , Mannheimia haemolytica/efeitos dos fármacos , Mannheimia haemolytica/genética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Pasteurella multocida/efeitos dos fármacos , Pasteurella multocida/genética , beta-Lactamases/genéticaRESUMO
In the light of frequent discussions about the correct performance of in vitro susceptibility testing and the interpretation of the results obtained, the aim of the present report is to summarize basic facts that may facilitate the understanding of this complex topic. For this, the terms "antimicrobial resistance", "ESBL", and "MRSA" are defined. Besides the statements on antimicrobial resistance, information on intrinsic and acquired resistance properties as well as basic rules for the correct performance of antimicrobial susceptibility testing in routine diagnostics are presented. Moreover, the two groups of interpretive criteria--clinical breakpoints and epidemiological cut-off values--including their applications are explained in detail. Furthermore, currently valid diagnostic procedures--as published by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standards Institute (CLSI)--for the screening of ESBL-producing Enterobacteriaceae and MRSA as well as for the confirmation of suspicious isolates are presented and compared. Based on the information given, it becomes obvious that the correct performance of the diagnostic tests, which includes strict following the performance standards and the detailed information given therein, is an indispensable prerequisite for a standardized and harmonized in vitro susceptibility testing and--as a consequence--for the determination of valid and reliable susceptibility data in routine diagnostics. This is of utmost importance since the susceptibility data based on the use of clinical breakpoints often represent the basis for therapeutic interventions.
Assuntos
Enterobacteriaceae/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Medicina Veterinária/métodos , Animais , Infecções Bacterianas/microbiologia , Infecções Bacterianas/veterinária , Técnicas Bacteriológicas/métodos , Farmacorresistência Bacteriana , Terminologia como Assunto , beta-LactamasesRESUMO
Mannheimia haemolytica is the major bacterial component in the bovine respiratory disease complex, which accounts for considerable economic losses to the cattle industry worldwide. The complete genome sequence of M. haemolytica strain 42548 was determined. It has a size of 2.73 Mb and contains 2,888 genes, including several antibiotic resistance genes.