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1.
Seputienė V Vilkoicaitė A Armalytė J Pavilonis A Sužiedėlienė E 《Folia microbiologica》2010,55(5):502-507
A screening method for methicillin-resistant Staphylococcus aureus (MRSA) using real-time polymerase chain reaction (PCR) and dye Syto 9 was developed and evaluated. The assay was based on
the two duplex reactions run simultaneously. The detection reaction amplified staphylococcal cassette chromosome mec (SCCmec) right extremity sequences and S. aureus-specific 442-bp DNA (Sa442). The control reaction amplified S. aureus-specific nuclease gene nuc and a marker of methicillin resistance, mecA. The method was evaluated by analyzing 214 clinical S. aureus isolates yielding 98.7 % sensitivity, 100 % specificity, 100 % positive predictive value and 96.6 % negative predictive value
for detection of MRSA. The detection limit was determined to be 15–80 genome copies per real-time PCR. It was able to discriminate
between MRSA, methicillin resistant coagulase negative staphylococci and methicillin susceptible S. aureus (MSSA) isolates containing only small fragments of the right extremity of the SCCmec (MSSA revertants). 相似文献
2.
Seventy-eight staphylococcal strains were isolated from surgical-site, blood-stream and other hospital-acquired infections.
Eighteen isolates were determined as methicillin (MET)-resistant S. aureus (MRSA), while the remaining were MET-resistant coagulase-negative staphylococci (CoNS). Fifty percent of CoNS strains were
multiresistant, while 10 % of isolates were resistant only to β-lactams. Clinical isolates of CoNS were generally more resistant
to antimicrobial agents than S. aureus strains. Thirty-nine % of S. aureus strains were resistant only to β-lactams. None of the MRSA strains carried ileS-2 gene; this gene was found in two strains of S. epidermidis. 相似文献
3.
Identification ofStaphylococcus aureus nuclease by seroinhibition in blood culture supernatant fluid
A rapid (2 h) method forStaphylococcus aureus identification by seroinhibition of staphylococcal thermonuclease has been developed and applied to blood cultures. No false positive reaction occurred in blood cultures containing isolates other thanS. aureus, and only one false negative among 31S. aureus-positive blood cultures was found. 相似文献
4.
Staphylococcus aureus and Staphylococcal Enterotoxin A in Breaded Chicken Products: Detection and Behavior during the Cooking Process 总被引:2,自引:0,他引:2
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Olimpia Pepe Giuseppe Blaiotta Francesca Bucci Marilena Anastasio Maria Aponte Francesco Villani 《Applied microbiology》2006,72(11):7057-7062
In this study we examined the presence of Staphylococcus aureus and staphylococcal enterotoxin A (SEA) in 20 industrial breaded chicken products obtained from different retail butchers and supermarket stores in Italy. The levels of contamination in the products analyzed were quite low, although the pH values and water activities (aw) in the samples considered were in ranges favorable for S. aureus growth. As demonstrated by phenotypic and molecular characterization, in spite of the high percentage of coagulase-positive Staphylococcus strains, only three strains could be referred to the species S. aureus. Moreover, all the strains were negative in PCR assays targeting staphylococcal enterotoxin genes (seA to seE, seG to seJ, and seM to seO), as well as the toxic shock syndrome toxin 1 gene, and no SEA was detected in the retail breaded chicken samples analyzed by a reversed passive latex agglutination assay or by Western blotting. Hence, we evaluated the thermal resistance of two strains of SEA-producing S. aureus in a laboratory-scale preparation of precooked breaded chicken cutlets. The heat treatment employed in the manufacture determined the inactivation of S. aureus cells, but the preformed SEA remained active during product storage at 4°C. The presence of the staphylococci and, in particular, of S. aureus in the retail breaded chicken products analyzed is a potential health risk for consumers since the pH and aw values of these kinds of products are favorable for S. aureus growth. The thermal process used during their manufacture can limit staphylococcal contamination but cannot eliminate preformed toxins. 相似文献
5.
The staphylococcal nuclease, encoded by the nuc1 gene, is an important virulence factor of Staphylococcus aureus. However, the physiological role of the nuclease has not been fully characterized. The current study observed that biofilm
development could be prevented in staphylococcal nuclease-producing strains of S. aureus; however, when the nuc1 gene was knocked out, the ability to form a biofilm significantly increased. Scanning electron and confocal scanning laser
microscopy were used to evaluate the role of the nuc1 gene in biofilm formation. Moreover, the nuc1 gene product, staphylococcal nuclease, and recombinant NUC1 protein were found to have a visible effect on other biofilm-forming
bacteria, such as Pseudomonas aeruginosa, Actinobacillus pleuropneumoniae, and Haemophilus parasuis. The current study showed a direct relationship between staphylococcal nuclease production and the prevention of biofilm
development. The findings from this study underscore the important role of staphylococcal nuclease activity to prevent biofilm
formation in S. aureus. They also provided evidence for the biological role of staphylococcal nucleases in other organisms. 相似文献
6.
J. P. Maskell 《Antonie van Leeuwenhoek》1980,46(4):343-351
The functional interchangeability of staphylococcal and enterobacterial iron chelators was investigated with an indicator system in which minimally effective concentrations of ethylene diamine di-ortho-hydroxyphenyl acetic acid (EDDA) were used to inhibit the growth of indicator strains in the depth of simple agar media by making the iron unavailable. Test colonies were then applied to the surface of the media to determine whether the indicator organisms, by utilising chelators from the test colony could obtain the required iron for growth, in its vicinity.Approximately 50% of staphylococcal strains, both S. aureus and S. epidermidis, reversed the inhibition of enterobacterial indicators, whereas almost all enterobacterial test strains, representing five genera, reversed the inhibition of the staphylococcal indicators. A purified preparation of the enterobacterial iron chelator enterochelin also reversed the inhibition of four out of the five staphylococcal indicator strains. 相似文献
7.
Paulina Nastaly Mariusz Grinholc Krzysztof P. Bielawski 《Archives of microbiology》2010,192(8):603-617
Infections caused by methicillin-resistant S. aureus strains are mainly associated with a hospital setting. However, nowadays, the MRSA infections of non-hospitalized patients
are observed more frequently. In order to distinguish them from hospital-associated methicillin-resistant S. aureus (HA-MRSA) strains, given them the name of community-associated methicillin-resistant S. aureus (CA-MRSA). CA-MRSA strains most commonly cause skin infections, but may lead to more severe diseases, and consequently the
patient’s death. The molecular markers of CA-MRSA strains are the presence of accessory gene regulator (agr) of group I or III, staphylococcal cassette chromosome mec (SCCmec) type IV, V or VII and genes encoding for Panton–Valentine leukocidin (PVL). In addition, CA-MRSA strains show resistance
to β-lactam antibiotics. Studies on the genetic elements of CA-MRSA strains have a key role in the unambiguous identification
of strains, monitoring of infections, improving the treatment, work on new antimicrobial agents and understanding the evolution
of these pathogens. 相似文献
8.
Elena Ramos-Trujillo Eduardo Pérez-Roth Sebastián Méndez-Álvarez Félix Claverie-Martín 《International microbiology》2003,6(2):113-115
The experimental transfer of the vanA gene cluster from Enterococcus faecalis to Staphylococcus aureus has raised fears about the occurrence of such genetic transfer in clinical isolates of methicillin-resistant staphylococci. Recently, infections by a S. aureus strain carrying the enterococcal vancomycin resistance vanA gene cluster were reported. The possible emergence and dissemination of these strains is a serious health threat and makes optimization of prevention strategies and fast detection methods absolutely necessary. In the present study, we developed a PCR protocol for simultaneous detection of enterococcal vanA and vanB genes , the staphylococcal methicillin and mupirocin resistance markers mecA and ileS-2, and identification of S. aureus. As no vancomycin-resistant S. aureus isolates were available for our study, we used mixtures of enterococcal and staphylococcal colonies that harbored the different resistance markers to show that these genes could be detected simultaneously. This protocol could be used to facilitate the detection and identification of predictable S. aureus or methicillin-resistant strains carrying vanA or vanB. 相似文献
9.
10.
Lynn El Haddad Nour Ben Abdallah Pier-Luc Plante Jeannot Dumaresq Ramaz Katsarava Steve Labrie Jacques Corbeil Daniel St-Gelais Sylvain Moineau 《PloS one》2014,9(7)
Team1 (vB_SauM_Team1) is a polyvalent staphylococcal phage belonging to the Myoviridae family. Phage Team1 was propagated on a Staphylococcus aureus strain and a non-pathogenic Staphylococcus xylosus strain used in industrial meat fermentation. The two Team1 preparations were compared with respect to their microbiological and genomic properties. The burst sizes, latent periods, and host ranges of the two derivatives were identical as were their genome sequences. Phage Team1 has 140,903 bp of double stranded DNA encoding for 217 open reading frames and 4 tRNAs. Comparative genomic analysis revealed similarities to staphylococcal phages ISP (97%) and G1 (97%). The host range of Team1 was compared to the well-known polyvalent staphylococcal phages phi812 and K using a panel of 57 S. aureus strains collected from various sources. These bacterial strains were found to represent 18 sequence types (MLST) and 14 clonal complexes (eBURST). Altogether, the three phages propagated on S. xylosus lysed 52 out of 57 distinct strains of S. aureus. The identification of phage-insensitive strains underlines the importance of designing phage cocktails with broadly varying and overlapping host ranges. Taken altogether, our study suggests that some staphylococcal phages can be propagated on food-grade bacteria for biocontrol and safety purposes. 相似文献
11.
12.
Miyo Murai Keiko Seki Junji Sakurada Akemi Usui Shogo Masuda 《Microbiology and immunology》1995,39(9):725-728
Intratumoral growth of Staphylococcus aureus Cowan I-derived AP332 was examined by subcutaneous inoculation of cocci in doses ranging from 18 to 1.8 × 105 CFU with Ehrlich ascites tumor cells. Inoculation of 18 CFU AP332 resulted in staphylococcal growth in one of five mice, and the proportion of mice established intratumoral infection increased with the initial inocula. Six other strains of S. aureus also grew in the tumor tissue, and none of the three strains of coagulase-negative staphylococci grew at all. Ethanol-killed tumor cells did not promote staphylococcal growth as vigorously as the live tumor cells, especially when the initial inoculum of AP332 was smaller than 104 CFU. 相似文献
13.
J. Kurlenda M. Grinholc J. Krzysztoń-Russjan K. Wiśniewska 《Antonie van Leeuwenhoek》2009,95(4):387-394
During a 1-month period, eight neonates developed staphylococcal skin disease diagnosed as a bullous impetigo in the maternity
unit of the Provincial Hospital in Gdansk. An epidemiological investigation based on phenotyping and genotyping methods was
performed. All neonates involved in the outbreak, their mothers and 15 staff members were screened for carriage of Staphylococcus aureus by nasal swabs. Isolated strains were compared with strains cultured from affected skin and purulent conjunctiva of infected
newborns. Isolates were analyzed for the presence of the etA and etB genes using polymerase chain reaction and genotyped by pulsed-field gel electrophoresis (PFGE) and coa gene polymorphism. The analyzed S. aureus strains were methicillin-sensitive and could be divided into two groups according to antibiotyping, phage typing, coa polymorphism and PFGE pattern. The first group consisted of etA and etB negative strains, and the second one involved only the etB positive ones. Our results have shown that there were two different clusters of infection caused by two populations of S. aureus strains. Among the 15 medical staff members screened we have found seven carriers. However, phage typing revealed that distinct
strains unrelated to the outbreak isolates were carried. Although we have not been able to establish the source of bacteria
involved in the outbreak, our results suggest that for both groups, mothers could be the source of the infecting strains.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Kilic A Mert G Senses Z Bedir O Aydogan H Basustaoglu AC Appelbaum PC 《Antonie van Leeuwenhoek》2008,94(4):615-619
Methicillin-resistant Staphylococcus aureus (MRSA) colonize most frequently in the anterior nares of the nose and cause serious infections all over the world. The aim
of this study was to determine the nasal carriage rate of S. aureus and MRSA strains in Turkish elementary school children. We also analyzed molecular characterizations of MRSA strains by using
pulse field gel electrophoresis (PFGE), multi locus sequence typing (MLST), staphylococcal chromosomal cassette mec (SCCmec) typing, and detection of the Panton-valentine leucocidin (PVL) gene. The nasal swabs were obtained from 4,050 children during
a 4 month period in Ankara. In vitro antimicrobial susceptibility testing to 1 μg oxacillin and 30 μg cefoxitin was determined
by a disk diffusion method. We found that the 1,001 of 4,050 (24.7%) children were colonized with S. aureus. Three S. aureus strains were resistant to oxacillin and cefoxitin. The rate of MRSA among all children was 0.07%. The MRSA strains revealed
three different PFGE pattern. All MRSA isolates by harbored the SCCmec type IV element, but not the PVL gene. The two MRSA isolate belonged to sequence type (ST) 30, whereas the other one was
a unique type. The results of this study demonstrated that S. aureus nasal carriage rate was consistent with previous studies. However, MRSA carriage rate was low. This study also indicated
that the ST30-type IV without PVL gene MRSA clone may be expected to spread in Turkish community. 相似文献
15.
Staphylococcus aureus is the leading cause of bacteraemia and the dwindling supply of effective antibacterials has exacerbated the problem of managing infections caused by this bacterium. Isoliquiritigenin (ISL) is a plant flavonoid that displays therapeutic potential against S. aureus. The present study identified a novel mannich base derivatives of ISL, IMRG4, active against Vancomycin intermediate S. aureus (VISA). IMRG4 damages the bacterial membranes causing membrane depolarization and permeabilization, as determined by loss of salt tolerance, flow cytometric analysis, propidium idodie and fluorescent microscopy. It reduces the intracellular invasion of HEK-293 cells by S. aureus and decreases the staphylococcal load in different organs of infected mice models. In addition to anti-staphylococcal activity, IMRG4 inhibits the multidrug efflux pump, NorA, which was determined by molecular docking and EtBr efflux assays. In combination, IMRG4 significantly reduces the MIC of norfloxacin for clinical strains of S. aureus including VISA. Development of resistance against IMRG4 alone and in combination with norfloxacin was low and IMRG4 prolongs the post-antibiotic effect of norfloxacin. These virtues combined with the low toxicity of IMRG4, assessed by MTT assay and haemolysis, makes it an ideal candidate to enter drug development pipeline against S. aureus. 相似文献
16.
A.J. O’Neill 《Letters in applied microbiology》2010,51(3):358-361
Aims: To provide comparative genome sequence data for two related model strains of Staphylococcus aureus (SH1000 and 8325‐4) that are used extensively in laboratory research. Methods and Results: Comparative genome sequencing was used to identify genetic differences between Staph. aureus SH1000 and the fully genome‐sequenced ancestral strain, Staph. aureus NCTC 8325. PCR amplification and DNA sequencing were employed to determine which of the genetic polymorphisms identified were also present in Staph. aureus 8325‐4, a direct derivative of 8325 and the parent strain of SH1000. Aside from known genetic differences between these strains, Staph. aureus SH1000 harboured 15 single‐nucleotide polymorphisms compared with 8325 (of which 12 were also found in 8325‐4), and a 63‐bp deletion upstream of the spa gene not present in either 8325 or 8325‐4. Conclusions: Staphylococcus aureus SH1000 and 8325‐4 contain a number of genetic polymorphisms relative to the progenitor strain of the lineage (8325) and to each other. Significance and Impact of the Study: The comparative genome sequences of SH1000 and 8325‐4 presented here define the genotypes of two key strains in staphylococcal laboratory research and reveal genetic polymorphisms that may impact their phenotypic properties. 相似文献
17.
Yusuke Sato'o Katsuhiko Omoe Hisaya K. Ono Akio Nakane Dong‐Liang Hu 《Microbiology and immunology》2013,57(2):91-99
Staphylococcus aureus pathogenicity islands (SaPIs) form a growing family of mobile genetic elements (MGEs) in Staphylococci. Horizontal genetic transfer by MGEs plays an important role in the evolution of S. aureus. Several SaPIs carry staphylococcal enterotoxin and SE‐like toxin genes. To comprehensively investigate the diversity of SaPIs, a series of primers corresponding to sequences flanking six SaPI insertion sites in S. aureus genome were designed and a long and accurate (LA)‐PCR analysis method established. LA‐PCR products of 13–17 kbp were observed in strains with seb, selk or selq genes. Restriction fragment length polymorphism (RFLP) analysis showed that the products have different RFLP characteristics than do previously described SaPIs; they were therefore predicted to include new SaPIs. Nucleotide sequencing analysis revealed seven novel SaPIs: seb‐harboring SaPIivm10, SaPishikawa11, SaPIivm60, SaPIno10 and SaPIhirosaki4, selk and selq‐harboring SaPIj11 and non‐superantigen‐harboring SaPIhhms2. These SaPIs have mosaic structures containing components of known SaPIs and other unknown genes. Strains carrying different SaPIs were found to have significantly different production of superantigen toxins. The present results show that the LA‐PCR approach can comprehensively identify SaPI diversity and is useful for investigating the evolution of S. aureus pathogenicity. 相似文献
18.
19.
Zarizal Suhaili Saiful Azmi Johari Mastura Mohtar Ahmad Rushdi Tan Abdullah Affandi Ahmad Abdul Manaf Ali 《World journal of microbiology & biotechnology》2009,25(2):253-258
The aim of this study was to develop a methicillin-resistant Staphylococcus aureus (MRSA) detection method based on the melting temperature analysis profiling of S. aureus clinical isolates from three different hospitals in Malaysia. Simplex and duplex real-time PCR assay was used for the simultaneous
detection of nuc (species-specific) and mecA (methicillin-resistance) genes in a single SYBR Green I real-time PCR tube assay. Evaluations were based on the melting temperature
(T
m) analysis of the amplicons using 23 S. aureus clinical isolates including three ATCC S. aureus standard strains. Real-time PCR amplification products with melting peaks at 78.39 ± 0.4°C and 74.41 ± 0.6°C were detected
for nuc and mecA genes, respectively. Each real-time PCR assay was completed within two hours. This rapid genotypic method is useful for the
detection of resistant determinant (mecA) and identification of S. aureus (nuc) clinical isolates, thus benefiting patient therapy in hospitals. 相似文献
20.
Staphylococcus aureus, which mediated binding to heparan sulfate, and also strains of coagulase-negative staphylococci (CNS) adhered in high numbers
to polymers with end-point attached heparin. A characteristic feature of several cell growth factors is strong affinity for
heparin. In the present study, binding of the 125I-labeled heparin-binding growth factors (HBGF), acidic and basic fibroblast growth factor (aFGF, bFGF), and platelet-derived
growth factor (PDGF) by S. aureus and CNS strains was examined. Staphylococcal strains used in this study bind bFGF and PDGF, but not aFGF. The binding of
bFGF and PDGF was time dependent, influenced by pH and ionic strength for S. aureus Cowan 1. Preincubation of staphylococcal cells with unlabeled bFGF enhanced bFGF binding, but heparin, protamine sulfate,
poly-L-lysine, and suramin were potent inhibitors of 125I-bFGF binding to cells of S. aureus Cowan 1. Glycosaminoglycans of comparable size (chondroitin sulfate), other polysulfated polymers (λ-carrageenan, fucoidan),
and some polysulfated polysaccharides (dextran sulfate, pentosan polysulfate) inhibited binding of both GFs to various extents.
The partial inhibition of binding of both GFs after protease and periodate treatments indicates that both proteinaceous and
other carbohydrate moieties participate in the binding. A lysozyme cell surface extract and bacterial lysates of S. aureus Cowan 1 competitively inhibited binding of 125I-bFGF and 125I-PDGF. These results suggest that staphylococci have the ability to bind two of the HBGFs, bFGF and PDGF, but not aFGF, via
more than one cell structure. These binding structures seem to be exposed on the cell surface and deeply anchored in the cytoplasmic
membrane as well. 相似文献