title: Recovery method development of sodium chloride-susceptible methicillin-resistant Staphylococcus aureus isolates from ground pork samples.
abstract: The growth of certain methicillin-resistant Staphylococcus aureus (MRSA) isolates could be inhibited by NaCl higher than 2.5%. The objective of this study was to develop an enrichment method to recover NaCl-susceptible MRSA isolates from meat samples. The growth of 12 MRSA and 10 non-MRSA strains was measured in Mueller-Hinton (MH) broth supplemented with 2.5%, 4%, 6.5%, and 7.5% NaCl. Selective agents, including aztreonam, polymyxin B, NaCl, nalidixic acid, and NaN3, were determined for their inhibitory effect to MRSA and non-MRSA strains in MH broth. Based on these data, a two-step enrichment method was developed to recover both NaCl-susceptible and -resistant MRSA isolates in meat products. Comparing to the enrichment method that only used MH broth supplemented with 6.5% NaCl, five additional NaCl-susceptible MRSA isolates were recovered from 92 retail ground pork samples by this newly developed two-step enrichment method. To the best of our knowledge, this is the first study that considers NaCl-susceptible MRSA recovery from ground pork samples. The application of this new enrichment method might expand the diversity of MRSA isolates recovered from various samples.
authors.affiliation: 1 Tianjin Entry-Exit Inspection and Quarantine Bureau , Beijing, People's Republic of China .
authors.forename: Lu
authors.initials: L
authors.lastname: Pang
authors.forename: Yanping
authors.initials: Y
authors.lastname: Luo
authors.forename: Yihai
authors.initials: Y
authors.lastname: Gu
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
authors.forename: Fenglan
authors.initials: F
authors.lastname: Zhang
authors.forename: Shenghui
authors.initials: S
authors.lastname: Cui
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002681:China; D003470:Culture Media / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D005516:Food Microbiology; D008461:Meat Products / Q000382:microbiology*; D008712:Methicillin / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D012965:Sodium Chloride / Q000494:pharmacology; D034421:Sus scrofa / Q000382:microbiology*; D013552:Swine
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D012965:Sodium Chloride; D008712:Methicillin