ABSTRACT
ABSTRACT: This research aimed to detect coagulase-positive Staphylococcus (CPS) directly in samples of artificially contaminated milk, using multiplex PCR (mPCR). Standard and isolated bacterial strains of S. aureus, S. epidermidis, S. hyicus, S. intermedius, Listeria monocytogenes and Escherichia coli species were used, evaluating the specificity and detection limit of mPCR, for artificially contaminated UHT milk. Primers specific for the nuc gene (NUC1-NUC2 were used for S. aureus, NUC3-NUC4 for S. hyicus and NUC5-NUC6 for S. intermedius). It was possible to detect the three target species by mPCR, directly from bovine whole milk, with adequate specificity and acceptable detention limit for identification of coagulase-positive Staphylococcus (CPS) in foods. The specificity was determined by the amplification of species-specific fragments, and the detection limit was assessed by the detection thresholds obtained for the three species (103 CFU mL-1). From these results, the mPCR described, with the proposed set of primers, has the potential for use in precise identification and differentiation between CPSs in milk samples.
RESUMO: Esta pesquisa teve como objetivo detectar diretamente em amostras de leite contaminado artificialmente Staphylococcus coagulase positiva (ECP) por multiplex PCR (mPCR). Cepas padrão e isolados de S. aureus, S. epidermidis, S. hyicus, S. intermedius, Listeria monocytogenes e Escherichia coli foram utilizados no estudo. Foram utilizados primers específicos para o gene nuc (NUC1-NUC2 para o S. aureus, NUC3-NUC4 para o S. hyicus e NUC5-NUC6 para o S. intermedius ). Foi possível detectar as três espécies-alvo por mPCR, formar diretamente nas amostras de leite integral bovino, com especificidade adequada e limite de detecção aceitável para identificação de espécies de Staphylococcus coagulase positiva (ECP) em alimentos. A especificidade foi determinada por meio da amplificação de fragmentos específicos das espécies e o limite de detecção foi avaliado pelos limiares de detecção obtidos para as três espécies (103 UFC mL-1 para as espécies presentes nas amostras de leite contaminadas artificialmente).
ABSTRACT
Objective To understand the colonization ,distribution and prevention of methicillin‐resistant Staphylococcus aureus (MRSA) in ICU .Methods The nasal vestibule swabs were immediately taken from new patients in ICU and the sputum suction catheter specimens were collected from the patients conforming to respiratory tract infection at 72 h after entering ICU .The fluores‐cence PCR was adopted to rapidly detect mecA ,nuc gene .The related environment specimens such as nasal cavity and hands in med‐ical staffs were performed the regular tracking monitoring ,prevention and control .Results The MRSA‐detection rates were 9 .9%for nasal vestibule swabs ,2 .7% for sputum suction catheter ;7 .1% for nasal vestibule swabs of medical staffs ,4 .0% for hands and 4 .4% for cuffs;the medical staffs and patient′s nasal cavity with MRSA‐positive adopted mupirocin for scrubing ,MRSA detection rate in hands after reinforce disinfection was 0 .0% ,but nasal cavity MRSA in medical staff was still detected out every quarter . Conclusion The PCR method has significantly higher positive detection rate compared with the conventional culture method .Nasal vestibule is a major colonization site of M RSA and the main infection source of infection ,the hands are the important route of trans‐mission ,monitoring nasal vestibule in ICU patients and medical staffs and hands in medical staffs is important to control MRSA nosocomial infection .
ABSTRACT
Sixty-five strains of coagulase positive staphylococci (Staphylococcus aureus, S. intermedius and S. hyicus) were identified at species level by PCR amplification of the coa gene, specific for S. aureus, and of the nuc gene, specific for S. intermedius and for S. hyicus.
Sessenta e cinco cepas de estafilococos coagulase positiva foram identificadas em nível de espécie, através da amplificação, por PCR, de seqüências do gene coa, específicas para S. aureus, e do gene nuc, específicas para S. intermedius e para S. hyicus.
ABSTRACT
Sixty-five strains of coagulase positive staphylococci (Staphylococcus aureus, S. intermedius and S. hyicus) were identified at species level by PCR amplification of the coa gene, specific for S. aureus, and of the nuc gene, specific for S. intermedius and for S. hyicus.
Sessenta e cinco cepas de estafilococos coagulase positiva foram identificadas em nível de espécie, através da amplificação, por PCR, de seqüências do gene coa, específicas para S. aureus, e do gene nuc, específicas para S. intermedius e para S. hyicus.