Sassi, Mohamed; Sharma, Deepak; Brinsmade, Shaun ,; Felden, Brice; Augagneur, Yoann
We report here the draft genome sequence of Staphylococcus aureus subsp. aureus strain UAMS-1. UAMS-1 is a virulent oxacillin-susceptible clinical isolate. Its genome is composed of 2,763,963 bp and will be useful for further gene expression analysis using RNA sequencing (RNA-seq) technology. S taphylococcus aureus is an opportunistic human bacterial pathogen responsible for nosocomial and community-associated infections. S. aureus subsp. aureus strain UAMS-1 was originally isolated from the ...
Boles, Blaise R.; Thoendel, Matthew; Roth, Aleeza J.; Horswill, Alexander R.
Staphylococcus aureus is a potent biofilm former on host tissue and medical implants, and biofilm growth is a critical virulence determinant for chronic infections. Recent studies suggest that many clinical isolates form polysaccharide-independent biofilms. However, a systematic screen for defective mutants has not been performed to identify factors important for biofilm formation in these strains. We created a library of 14,880 mariner transposon mutants in a S. aureus strain that generates ...
Holtfreter, Silva; Fiona J Radcliff; Grumann, Dorothee; Read, Hannah; Johnson, Sarah; Monecke, Stefan; Ritchie, Stephen; Clow, Fiona; Goerke, Christiane; Bröker, Barbara M.; Fraser, John D.; Wiles, Siouxsie
More effective antibiotics and a protective vaccine are desperately needed to combat the ‘superbug’ Staphylococcus aureus. While in vivo pathogenicity studies routinely involve infection of mice with human S. aureus isolates, recent genetic studies have demonstrated that S. aureus lineages are largely host-specific. The use of such animal-adapted S. aureus strains may therefore be a promising approach for developing more clinically relevant animal infection models. We have isolated a mouse-ad...
Gottlieb, Caroline Trebbien; Thomsen, L.E.; Ingmer, H.;
the human β-defensin 3 (HBD-3). All strains were inhibited by concentrations of hydrogen peroxide between 0.1% – 1.0%. Sub-selections of both species differed in expression of several virulence-related factors and in their ability to survive in human whole blood and kill the nematode virulence model...
Kim, Bong-Soo; Yi, Hana; Chun, Jongsik; Cha, Chang-Jun
Background Staphylococcus aureus is a pathogen that causes food poisoning and community-associated infection with antibiotic resistance. This species is an indigenous intestinal microbe found in infants and not found in adult intestine. The relatively small genome size and rapid evolution of antibiotic resistance genes in the species have been drawing an increasing attention in public health. To extend our understanding of the species and use the genome data for comparative genomic studies, w...
Grzegorczyk, Agnieszka; Malm, Anna
The paper presents results on the relatedness of Staphylococcus aureus strains colonizing the upper respiratory tract isolated from healthy persistent carriers. Genotyping was carried out using two methods--multiple-locus variable-number tandem-repeat fingerprinting (MLVF) and pulsed-field gel electrophoresis (PFGE). By comparison of the results obtained by both methods, good correlations between MLVF and PFGE genotyping of strains isolated from the asymptomatic carriers were observed. Further studies are needed to evaluate methods useful for genotyping of S. aureus strains circulating in the community. PMID:24488811
Wang, Junfeng; Liu, Yanhong; Wan, Daiwei; Fang, Xiangqun; Li, Tianzhi; Guo, Yinghua; Chang, De; Su, Longxiang; Wang, Yajuan; Zhao, Jiao; Liu, Changting
Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. S. aureus is the most common species of Staphylococcus to cause staphylococcal infections, which are very common in clinical medicine. Here we report the genome sequence of S. aureus strain LCT-SA112, which was isolated from S. aureus subsp. aureus CGMCC 1.230.
Holtfreter, Silva; Radcliff, Fiona J; Grumann, Dorothee; Read, Hannah; Johnson, Sarah; Monecke, Stefan; Ritchie, Stephen; Clow, Fiona; Goerke, Christiane; Bröker, Barbara M; Fraser, John D; Wiles, Siouxsie
More effective antibiotics and a protective vaccine are desperately needed to combat the 'superbug' Staphylococcus aureus. While in vivo pathogenicity studies routinely involve infection of mice with human S. aureus isolates, recent genetic studies have demonstrated that S. aureus lineages are largely host-specific. The use of such animal-adapted S. aureus strains may therefore be a promising approach for developing more clinically relevant animal infection models. We have isolated a mouse-adapted S. aureus strain (JSNZ) which caused a severe outbreak of preputial gland abscesses among male C57BL/6J mice. We aimed to extensively characterize this strain on a genomic level and determine its virulence potential in murine colonization and infection models. JSNZ belongs to the MLST type ST88, rare among human isolates, and lacks an hlb-converting phage encoding human-specific immune evasion factors. Naive mice were found to be more susceptible to nasal and gastrointestinal colonization with JSNZ than with the human-derived Newman strain. Furthermore, naïve mice required antibiotic pre-treatment to become colonized with Newman. In contrast, JSNZ was able to colonize mice in the absence of antibiotic treatment suggesting that this strain can compete with the natural flora for space and nutrients. In a renal abscess model, JSNZ caused more severe disease than Newman with greater weight loss and bacterial burden. In contrast to most other clinical isolates, JSNZ can also be readily genetically modified by phage transduction and electroporation. In conclusion, the mouse-adapted strain JSNZ may represent a valuable tool for studying aspects of mucosal colonization and for screening novel vaccines and therapies directed at preventing colonization. PMID:24023720
Full Text Available More effective antibiotics and a protective vaccine are desperately needed to combat the 'superbug' Staphylococcus aureus. While in vivo pathogenicity studies routinely involve infection of mice with human S. aureus isolates, recent genetic studies have demonstrated that S. aureus lineages are largely host-specific. The use of such animal-adapted S. aureus strains may therefore be a promising approach for developing more clinically relevant animal infection models. We have isolated a mouse-adapted S. aureus strain (JSNZ which caused a severe outbreak of preputial gland abscesses among male C57BL/6J mice. We aimed to extensively characterize this strain on a genomic level and determine its virulence potential in murine colonization and infection models. JSNZ belongs to the MLST type ST88, rare among human isolates, and lacks an hlb-converting phage encoding human-specific immune evasion factors. Naive mice were found to be more susceptible to nasal and gastrointestinal colonization with JSNZ than with the human-derived Newman strain. Furthermore, naïve mice required antibiotic pre-treatment to become colonized with Newman. In contrast, JSNZ was able to colonize mice in the absence of antibiotic treatment suggesting that this strain can compete with the natural flora for space and nutrients. In a renal abscess model, JSNZ caused more severe disease than Newman with greater weight loss and bacterial burden. In contrast to most other clinical isolates, JSNZ can also be readily genetically modified by phage transduction and electroporation. In conclusion, the mouse-adapted strain JSNZ may represent a valuable tool for studying aspects of mucosal colonization and for screening novel vaccines and therapies directed at preventing colonization.
Full Text Available In the research work the results of the study of resistance forming to antibiotics, antiseptics and decametoxine composition with modified polysaccharides in S.aureus strains are presented. The development of resistance to penicillins, cephalosporins, glycopeptides, macrolides is shown. Slow forming of resistance to decasan and decametoxine composition with carboxymethylamylum, oxyethylcellulose was determined.
Donnio, Pierre-Yves; Février, Frédéric; Bifani, Pablo; Dehem, Marie; Kervégant, Christèle; Wilhelm, Nathalie; Gautier-Lerestif, Anne-Lise; Lafforgue, Nathalie; Cormier, Michel; Le Coustumier, Alain
The excision of the staphylococcal chromosomal cassette mec (SCCmec) from methicillin-resistant Staphylococcus aureus (MRSA) strains results in methicillin-susceptible S. aureus (MSSA) strains. In order to determine the proportion and diversity of multidrug-resistant MSSA (MR-MSSA) strains derived from MRSA strains, 247 mecA-negative isolates recovered in 60 French hospitals between 2002 and 2004 were characterized. The spa types of all strains were determined, and a subset of the strains (n = 30) was further genotyped by multilocus sequence typing. The IDI-MRSA assay was used to test the isolates for the presence of the SCCmec element, which was detected in 68% of all isolates analyzed. Molecular analysis of the samples suggested that 92% of the MR-MSSA isolates were derived from MRSA clones of diverse genetic backgrounds, of which the clone of sequence type 8 and SCCmec type IVA accounted for most of the samples. High variations in incidence data and differences in the molecular characteristics of the isolates from one hospital to another indicate that the emergence of MR-MSSA resulted from independent SCCmec excisions from epidemic MRSA isolates, as well as the diffusion of methicillin-susceptible strains after the loss of SCCmec. MR-MSSA could constitute a useful model for the study of the respective genetic and environmental factors involved in the dissemination of S. aureus in hospitals. PMID:17709473
M. Nagel; Dischinger, J.; Türck, M.; Verrier, D.; Oedenkoven, M.; Ngoubangoye, B.; Le Flohic, G.; Drexler, J. F.; Bierbaum, G.; Gonzalez, Jean-Paul
The risk of serious infections caused by Staphylococcus aureus is well-known. However, most studies regarding the distribution of (clinically relevant) S.aureus among humans and animals took place in the western hemisphere and only limited data are available from (Central) Africa. In this context, recent studies focused on S.aureus strains in humans and primates, but the question of whether humans and monkeys share related S.aureus strains or may interchange strains remained largely unsolved....
Sung, Julia M.-L.; Lindsay, Jodi A
We identified naturally occurring Staphylococcus aureus mutants of the restriction modification pathway SauI, including bovine lineage ST151. In a model of vancomycin resistance transfer from Enterococcus faecalis, ST151 isolates are 500 times more susceptible than human S. aureus isolates. The eradication of “hyperrecipient” strains may reduce the evolution of vancomycin-resistant S. aureus.
Kant, Ravi; Taponen, Suvi; Koort, Joanna; Paulin, Lars; Åvall-Jääskeläinen, Silja; Palva, Airi
Staphylococcus aureus is a major causative agent of mastitis in dairy cows. The pathogenicity of S. aureus may vary; it is able to cause severe clinical mastitis, but most often it is associated with chronic subclinical mastitis. Here, we present the genome assemblies of four S. aureus strains from bovine mastitis.
Kant, Ravi; Taponen, Suvi; Koort, Joanna; Paulin, Lars; Åvall-Jääskeläinen, Silja; Palva, Airi
Staphylococcus aureus is a major causative agent of mastitis in dairy cows. The pathogenicity of S. aureus may vary; it is able to cause severe clinical mastitis, but most often it is associated with chronic subclinical mastitis. Here, we present the genome assemblies of four S. aureus strains from bovine mastitis. PMID:25908141
Poulsen, Marianne Ø; Jacobsen, Kirstine; Thorsing, Mette; Kristensen, Nadia R D; Clasen, Julie; Lillebæk, Eva M S; Skov, Marianne N; Kallipolitis, Birgitte H; Kolmos, Hans Jørn; Klitgaard, Janne K
The neuroleptic antipsychotic derivate thioridazine has been shown to increase the susceptibility of a methicillin-resistant Staphylococcus aureus (MRSA) isolate towards dicloxacillin. The aim of this study was to investigate the combinatorial effect of the two drugs on a broad selection of staphylococcal strains by analyzing a large collection of MRSA strains carrying different types of SCCmec, as well as MSSA strains. Transcription and translation of the resistance marker PBP2a encoded by mecA within the SCCmec cassette were analyzed by primer extension and western blotting. We observed increased susceptibility to dicloxacillin in the presence of thioridazine in all tested MRSA isolates. In contrast to previously published results, the synergistic effect was also applicable to methicillin-susceptible S. aureus (MSSA). We conclude that the combination of dicloxacillin and thioridazine potentiates the killing effect against S. aureus in a broad selection of clinical isolates. Additionally, the study indicates that the killing effect by the combinatorial treatment is independent of PBP2a-mediated resistance mechanisms. PMID:23089256
Musa, N. O.; Eltom, K.; Gessler, F.; H. Böhnel; Babiker, A.; Sanousi, S. M.
Staphylococcus aureus ssp anaerobius strain S10 was isolated from an outbreak of sheep abscess disease. Sequence of the catalase gene of this strain showed 99 % identity to the catalase gene (katB) sequence of the reference strain (S. aureus ssp. anaerobius strain MVF213) with mismatching of three base pairs. An important substitution located 1036 nucleotides upstream of the initiation codon from “C” in katB to “T” in the catalase gene of strain S10 originated a stop codon. The de...
Nagel, M; Dischinger, J; Türck, M; Verrier, D; Oedenkoven, M; Ngoubangoye, B; Le Flohic, G; Drexler, J F; Bierbaum, G; Gonzalez, J-P
The risk of serious infections caused by Staphylococcus aureus is well-known. However, most studies regarding the distribution of (clinically relevant) S. aureus among humans and animals took place in the western hemisphere and only limited data are available from (Central) Africa. In this context, recent studies focused on S. aureus strains in humans and primates, but the question of whether humans and monkeys share related S. aureus strains or may interchange strains remained largely unsolved. In this study we aimed to evaluate the distribution and spread of human-like S. aureus strains among great apes living in captivity. Therefore, a primate facility at the International Centre for Medical Research of Franceville (Gabon) was screened. We detected among the primates a common human S. aureus strain, belonging to the spa-type t148. It was isolated from three different individuals of the western lowland gorilla (Gorilla gorilla gorilla), of which one individual showed a large necrotizing wound. This animal died, most probably of a staphylococcal sepsis. Additionally, we discovered the t148 type among chimpanzees (Pan troglodytes) that were settled in the immediate neighbourhood of the infected gorillas. A detailed analysis by pulsed field gel electrophoresis showed that the gorilla and chimpanzee isolates represented two closely related strains. To our knowledge, this is the first report of a human-associated S. aureus strain causing disease in great apes. The simultaneous detection in gorillas and chimpanzees indicated an interspecies transmission of this S. aureus strain. Our results recommend that protection of wild animals must not only be based on habitat conservation, but also on the assessment of the risk of contact with human pathogens. PMID:23398468
Popoola, Victor O; Carroll, Karen C.; Ross, Tracy; Reich, Nicholas G.; Perl, Trish M.; Aaron M Milstone
We studied the transmissibility of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and healthcare-associated methicillin-resistant S. aureus (HA-MRSA) strains and the association of MRSA colonization pressure and MRSA transmission in critically ill children. Importantly, we found that in hospitalized children MRSA colonization pressure above 10% increases the risk of MRSA transmission 3-fold, and CA-MRSA and HA-MRSA strains have similar transmission dynamics.
Lee, Soomin; Ahn, Sooyeon; Lee, Heeyoung; Kim, Won-Il; Kim, Hwang-Yong; Ryu, Jae-Gee; Kim, Se-Ri; Choi, Kyoung-Hee; Yoon, Yohan
This study investigated the effect of adaptation of Staphylococcus aureus strains to the acidic condition of tomato in response to environmental stresses, such as heat and acid. S. aureus ATCC 13565, ATCC 14458, ATCC 23235, ATCC 27664, and NCCP10826 habituated in tomato extract at 35°C for 24 h were inoculated in tryptic soy broth. The culture suspensions were then subjected to heat challenge or acid challenge at 60°C and pH 3.0, respectively, for 60 min. In addition, transcriptional analysis using quantitative real-time PCR was performed to evaluate the expression level of acid-shock genes, such as clpB, zwf, nuoF, and gnd, from five S. aureus strains after the acid habituation of strains in tomato at 35°C for 15 min and 60 min in comparison with that of the nonhabituated strains. In comparison with the nonhabituated strains, the five tomato-habituated S. aureus strains did not show cross protection to heat, but tomato-habituated S. aureus ATCC 23235 showed acid resistance. In quantitative real-time-PCR analysis, the relative expression levels of acid-shock genes (clpB, zwf, nuoF, and gnd) were increased the most in S. aureus ATCC 23235 after 60 min of tomato habituation, but there was little difference in the expression levels among the five S. aureus strains after 15 min of tomato habituation. These results indicate that the variation of acid resistance of S. aureus is related to the expression of acid-shock genes during acid habituation. PMID:25285500
Cordwell, Stuart J; Larsen, Martin Røssel; Cole, Rebecca T;
profiles of S. aureus strains COL (methicillin-resistant) and 8325 (methicillin-sensitive). Reference mapping via this approach identified 377 proteins that corresponded to 266 distinct ORFs. Amongst these identified proteins were 14 potential virulence factors. The production of 41 'hypothetical' proteins...... was confirmed, and eight of these appeared to be unique to S. aureus. Strain COL displayed 12 protein spots, which included alkaline-shock protein 23 (Asp23) and cold-shock proteins CspABC, which either were not present in strain 8325 or were present at a significantly lower intensity in this strain....... Comparative maps were used to characterize the S. aureus response to treatment with Triton X-100 (TX-100), a detergent that has been shown to reduce methicillin resistance independently of an interaction with the mecA-encoded penicillin-binding protein 2a. In response to growth of the bacteria in the presence...
Baum, Cathrin; Haslinger-Löffler, Bettina; Westh, Henrik;
Staphylococcus aureus is a major human pathogen responsible for increasing the prevalence of community- and hospital-acquired infections. Protein A (SpA) is a key virulence factor of S. aureus and is highly conserved. Sequencing of the variable-number tandem-repeat region of SpA (spa typing......) provides a rapid and reliable method for epidemiological studies. Rarely, non-spa-typeable S. aureus strains are encountered. The reason for this is not known. In this study, we characterized eight non-spa-typeable bacteremia isolates. Sequencing of the entire spa locus was successful for five strains...... and revealed various mutations of spa, all of which included a deletion of immunoglobulin G binding domain C, in which the upper primer for spa typing is located, while two strains were truly spa negative. This is the first report demonstrating that nontypeability of S. aureus by spa sequencing is due either...
Baum, Cathrin; Haslinger-Löffler, Bettina; Westh, Henrik; Boye, Kit; Peters, Georg; Neumann, Claudia; Kahl, Barbara C
Staphylococcus aureus is a major human pathogen responsible for increasing the prevalence of community- and hospital-acquired infections. Protein A (SpA) is a key virulence factor of S. aureus and is highly conserved. Sequencing of the variable-number tandem-repeat region of SpA (spa typing......) provides a rapid and reliable method for epidemiological studies. Rarely, non-spa-typeable S. aureus strains are encountered. The reason for this is not known. In this study, we characterized eight non-spa-typeable bacteremia isolates. Sequencing of the entire spa locus was successful for five strains and...... revealed various mutations of spa, all of which included a deletion of immunoglobulin G binding domain C, in which the upper primer for spa typing is located, while two strains were truly spa negative. This is the first report demonstrating that nontypeability of S. aureus by spa sequencing is due either...
Johler, Sophia; Stephan, Roger; Althaus, Denise; Ehling-Schulz, Monika; Grunert, Tom
Staphylococcus aureus causes a variety of serious illnesses in humans and animals. Subtyping of S. aureus isolates plays a crucial role in epidemiological investigations. Metabolic fingerprinting by Fourier-transform infrared (FTIR) spectroscopy is commonly used to identify microbes at species as well as subspecies level. In this study, we aimed to assess the suitability of FTIR spectroscopy as a tool for S. aureus subtyping. To this end, we compared the subtyping performance of FTIR spectroscopy to other subtyping methods such as pulsed field gel electrophoresis (PFGE) and spa typing in a blinded experimental setup and investigated the ability of FTIR spectroscopy for identifying S. aureus clonal complexes (CC). A total of 70 S. aureus strains from human, animal, and food sources were selected, for which clonal complexes and a unique virulence and resistance gene pattern had been determined by DNA microarray analysis. FTIR spectral analysis resulted in high discriminatory power similar as obtained by spa typing and PFGE. High directional concordance was found between FTIR spectroscopy based subtypes and capsular polysaccharide expression detected by FTIR spectroscopy and the cap specific locus, reflecting strain specific expression of capsular polysaccharides and/or other surface glycopolymers, such as wall teichoic acid, peptidoglycane, and lipoteichoic acid. Supervised chemometrics showed only limited possibilities for differentiation of S. aureus CC by FTIR spectroscopy with the exception of CC45 and CC705. In conclusion, FTIR spectroscopy represents a valuable tool for S. aureus subtyping, which complements current molecular and proteomic strain typing. PMID:27021524
Bouchard, Damien; Peton, Vincent; Almeida, Sintia; Le Maréchal, Caroline; Miyoshi, Anderson; Azevedo, Vasco; Berkova, Nadia; Rault, Lucie; Francois, Patrice; Schrenzel, Jacques; Even, Sergine; Hernandez, David; Le Loir, Yves
Staphylococcus aureus is a major etiological agent of mastitis in ruminants. We report here the genome sequence of bovine strain Newbould 305, isolated in the 1950s in a case of bovine mastitis and now used as a model strain able to reproducibly induce chronic mastitis in cows.
Zhang, Lili; Li, Yuchen; Bao, Hongduo; Wei, Ruicheng; Zhou, Yan; Zhang, Hui; Wang, Ran
Staphylococcus aureus is a significant bacterial pathogen associated with bovine mastitis. The aim of the present study was to investigate and characterize of S. aureus strains isolated from the milk of cows suffering from mastitis in the mid-east of China. Among the 200 milk samples analyzed, 58 were positive for S. aureus, of these isolates, 11 isolates were methicillin-resistant Staphylococcus aureus (MRSA). All of the 58 S. aureus strains were classified in agr group I, while seven different sequence type (ST) patterns were identified and among them the most common was ST630 followed by ST188. All of the S. aureus isolates belonging to ST630 were resistant to more than four antimicrobials, and 22.2% of isolates belonging to ST188 were resistant to eight antimicrobials. Interestingly, while strong biofilm producers demonstrated higher resistance to multiple antimicrobials, they exhibited lower intracellular survival rates. The results of this study illustrated the distribution, antimicrobial susceptibility profiles, genotype, and the ability of biofilm production and mammary epithelial cells invasion of these S. aureus isolates. This study can provide the basis for the development of a disease prevention program in dairy farms to reduce the potential risk in both animal and human health. PMID:27265679
Watts, Andrew; Ke, Danbing; Wang, Qun; Pillay, Anil; Nicholson-Weller, Anne; Lee, Jean C.
Most isolates of Staphylococcus aureus produce a serotype 5 (CP5) or 8 (CP8) capsular polysaccharide. To investigate whether CP5 and CP8 differ in their biological properties, we created isogenic mutants of S. aureus Reynolds that expressed CP5, CP8, or no capsule. Biochemical analyses of CP5 and CP8 purified from the isogenic S. aureus strains were consistent with published structures. The degree of O acetylation of each polysaccharide was similar, but CP5 showed a greater degree of N acetyl...
Katayama, Yuki; Sekine, Miwa; Hishinuma, Tomomi; Aiba, Yoshifumi; Hiramatsu, Keiichi
Complete reconstitution of the vancomycin-intermediate Staphylococcus aureus (VISA) phenotype of strain Mu50 was achieved by sequentially introducing mutations into six genes of vancomycin-susceptible S. aureus (VSSA) strain N315ΔIP. The six mutated genes were detected in VISA strain Mu50 but not in N315ΔIP. Introduction of the mutation Ser329Leu into vraS, encoding the sensor histidine kinase of the vraSR two-component regulatory (TCR) system, and another mutation, Glu146Lys, into msrR, belonging to the LytR-CpsA-Psr (LCP) family, increased the level of vancomycin resistance to that detected in heterogeneous vancomycin-intermediate S. aureus (hVISA) strain Mu3. Introduction of two more mutations, Asn197Ser into graR of the graSR TCR system and His481Tyr into rpoB, encoding the β subunit of RNA polymerase, converted the hVISA strain into a VISA strain with the same level of vancomycin resistance as Mu50. Surprisingly, however, the constructed quadruple mutant strain ΔIP4 did not have a thickened cell wall, a cardinal feature of the VISA phenotype. Subsequent study showed that cell wall thickening was an inducible phenotype in the mutant strain, whereas it was a constitutive one in Mu50. Finally, introduction of the Ala297Val mutation into fdh2, which encodes a putative formate dehydrogenase, or a 67-amino-acid sequence deletion into sle1 [sle1(Δ67aa)], encoding the hydrolase of N-acetylmuramyl-l-alanine amidase in the peptidoglycan, converted inducible cell wall thickening into constitutive cell wall thickening. sle1(Δ67aa) was found to cause a drastic decrease in autolysis activity. Thus, all six mutated genes required for acquisition of the VISA phenotype were directly or indirectly involved in the regulation of cell physiology. The VISA phenotype seemed to be achieved through multiple genetic events accompanying drastic changes in cell physiology. PMID:27067329
Musa, N O; Eltom, K; Gessler, F; Böhnel, H; Babiker, A; El Sanousi, S M
Staphylococcus aureus ssp anaerobius strain S10 was isolated from an outbreak of sheep abscess disease. Sequence of the catalase gene of this strain showed 99% identity to the catalase gene (katB) sequence of the reference strain (S. aureus ssp. anaerobius strain MVF213) with mismatching of three base pairs. An important substitution located 1036 nucleotides upstream of the initiation codon from "C" in katB to "T" in the catalase gene of strain S10 originated a stop codon. The deduced protein (345 amino acids) is 105 amino acids shorter than that of katB. Partial sequence of the catalase gene of other 8 local isolates in addition to another reference strain (DSM 20714/ATCC 35844) revealed the same mutations in all local (African) strains, whereas the sequence of the reference (European) strain was typical to that of katB. Sequence of the catalase gene of S. aureus ssp. anaerobius strain S10 was deposited in GenBank under accession no. EU281993. PMID:20526831
Lahtinen, Sampo J; Jalonen, Lotta; Ouwehand, Arthur C; Salminen, Seppo J
Cell-free, pH-controlled supernatants of thirty-eight Bifidobacterium strains isolated from healthy elderly subjects were subjected to antimicrobial activity assay. Bioluminescent indicator strains Staphylococcus aureus RN4220, Escherichia coli K-12, and Salmonella enterica serovar Typhimurium ATCC 14028 were used as targets of antimicrobial activity. The effect of nutrient depletion on the inhibition was eliminated with spent-culture controls. Three out of thirty-eight Bifidobacterium strains were capable of inhibiting the growth of S. aureus. The inhibition was equal to 23.2+/-19.1% to 50.4+/-26.7% of the inhibition caused by 50 IU/ml nisin. Reuterin-producing positive strain Lactobacillus reuteri SD2112 was capable of 86.0+/-24.6% inhibition, but Bifidobacterium lactis Bb-12, a known probiotic strain, showed no inhibition. None of the strains was capable of inhibiting the growth of E. coli or S. enterica. The observed inhibition by bifidobacteria was related to hydrogen peroxide formation and possible production of heat-stable proteinaceous compounds. The results suggest that production of antimicrobial substances other than organic acids is not common among Bifidobacterium strains typical of elderly subjects. However, specific strains were identified which showed considerable inhibitory activity against S. aureus. PMID:17462772
Morteza Shojaei Moghadam; Susan Maleki; Esmaeil Darabpour; Hossein Motamedi; Seyyed Mansour Seyyed Nejad
Objective:To assess the antibacterial activity of eight Iranian plant extracts against Staphylococcus aureus (S. aureus)strains which were isolated from infected patients.Methods:The studied strains were isolated from urine, stool, blood and wound of infected patients and identified by biochemical tests. In further, the antibacterial activity of 8 ethanolic local plant extracts includingQuerqus brantii (Q. brantii),Ziziphus spina-christi (Z. spina-christi),Peganum harmala(P. harmala),Oliveira decumbens (O. decumbens),Galium tricornutum(G. tricornutum), Vitex pseudonegundo (Vi. pseudo negundo),Salvia officinalis (S. officinalis) ,Vaccaria pyramidata (V.pyramidata)were then evaluated using agar disc diffusion method.Results:A total of 9 isolates were isolated and identified asS. aureus. Antibacterial profile of the strains showed that the strains were resistant to methicillin and cefixime. The highest antibacterial activity against the studied strains were belong toQ. brantii,P. harmala,Z. spina-christi andO. decumbens vent extracts with 11-40 mm, 15-28 mm, 8-26 mm and 10-20 mm of diameters, respectively. Intermediate antibacterial activity was exhibited byG. tricornutum andVi. pseudo negundo against some of the studied strains with 7-20 mm and 7-13 mm of diameters, respectively. Noteworthy, out of 9 studied strains; 6 and 2 of them were resistant to theG. tricornutum andVi. pseudo negundo extracts, respectively. TheS. officinalis andVa. pyramidata, however, showed no antibacterial activity against the studied strains.Conclusions: TheQ. brantii,P. harmala,Z. spina-christi andO. decumbens extracts were shown to possess strong antibacterial activity against methicillin and cefixime resistant S. aureus strains and can be considered as the promising natural antibiotics for treating the studied strains.
Snel, Gustavo G M; Monecke, Stefan; Ehricht, Ralf; Piccinini, Renata
The biofilm-associated protein (Bap) of Staphylococcus aureus is a high molecular weight cell-wall-anchored protein involved in biofilm formation, first described in bovine mastitis strains from Spain. So far, studies regarding Bap were mainly based on the Spanish strain V329 and its mutants, but no information on the genetic variability of bap-positive Staph. aureus strains is yet available in the literature. The present study investigated the molecular characteristics of 8 bap-positive Staph. aureus strains from subclinical bovine mastitis, isolated in 5 herds; somatic cell counts (SCC) of milk samples were also registered. Strains were characterised using MLST, SPA typing and microarray and the results were compared with V329. All isolates from this study and V329 were assigned to ST126, t605, but some molecular differences were observed. Only herd A and B strains harboured the genes for β-lactams resistance; the leukocidin D/E gene, a type I site-specific deoxyribonuclease subunit, 3rd locus gene and serin-protease A and B were carried by all strains, but not by V329, while serin-protease E was absent in V329 and in another isolate. Four isolates and V329 harboured the fibronectin-binding protein B gene. SCC showed the highest value in the milk sample affected by the only strain carrying all the virulence factors considered. Potential large variability of virulence was evidenced among V329 and all bap-positive Staph. aureus strains considered: the carriage of fnb could enhance the accumulation of biofilm, but the lack of lukD/E and splA, B or E might decrease the invasiveness of strain. PMID:25850658
Full Text Available Staphylococcus (S. aureus and Pseudomonas (Ps. aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections.
I.V. Babushkina; V.B. Borodulin; G.V. Korshunov; D.M. Puchinjan
Research objective is to study antibacterial action of nanoparticles of iron and copper on polyantibiotically resistant clinical Staphylococcus aureus strains. Materials and methods include antibacterial action of nanoparticles of copper and iron on 10 Staphylococcus au¬reus strains, isolated from patients with purulent complications stayed in the in-patient department of traumatology and orthopedics. Solutions of powders of iron and copper have been prepared directly before the experiment in...
Abazar Pournajaf; Abdollah Ardebili; Leyla Goudarzi; Mahmoud Khodabandeh; Tahmineh Narimani; Hassan Abbaszadeh
Objective: To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification. Methods: A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates.Results:activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay. Among antibiotics used in our study, penicillin showed the least anti-staphylococcal Conclusions: This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic.
Baumgartner, Andreas; Niederhauser, Isabel; Johler, Sophia
Staphylococcal food poisoning represents the most prevalent foodborne intoxication worldwide. Oral intake of staphylococcal enterotoxins from food can result in emesis and diarrhea and can be fatal in children and the elderly. Few data have been available on the characteristics and sources of Staphylococcus aureus strains isolated from ready-to-eat (RTE) foods. In this study, we used a DNA microarray to determine virulence and antimicrobial resistance gene profiles of S. aureus from RTE foods. A total of 267 S. aureus strains isolated from 244 RTE foods were investigated. The isolates originated from precooked foods (41% of isolates), meat and fish products (17%), cheese (13%), delicatessen salads (8%), sandwiches and canapés (8%), confectionery and bakery products (6%), and various other RTE foods (7%). Eleven samples (5%), of which 9 were raw milk cheeses, contained > 10(5) CFU/g, which is considered a health risk. Four S. aureus strains were associated with intoxications; three cases were linked to consumption of cheese and one case was linked to consumption of potato salad. DNA microarray results revealed that one-third of the tested strains had at least one major enterotoxin gene (sea through see). We also detected the toxic shock syndrome gene (18% of isolates) and various genes conferring antimicrobial resistance, including genes involved in resistance to beta-lactams (blaZ, 72% of isolates), methicillin (mecA, 1% of isolates), and vancomycin (vanB, 1% of isolates). S. aureus strains were most frequently assigned to clonal complex (CC) 30 (17% of isolates), CC8 (12%), CC15 (11%), and CC45 (10%), which are commonly detected in humans colonized or infected with S. aureus. Although a large proportion of the tested food items contained milk, we did not detect CC705, the most prevalent clonal complex among S. aureus isolates from bovine mastitis milk. Our results suggest that S. aureus isolates from RTE foods do not commonly originate from animals but more
Phuti E Makgotlho
Full Text Available The Staphylococcus aureus regulatory saePQRS system controls the expression of numerous virulence factors, including extracellular adherence protein (Eap, which amongst others facilitates invasion of host cells. The saePQRS operon codes for 4 proteins: the histidine kinase SaeS, the response regulator SaeR, the lipoprotein SaeP and the transmembrane protein SaeQ. S. aureus strain Newman has a single amino acid substitution in the transmembrane domain of SaeS (L18P which results in constitutive kinase activity. SDS was shown to be one of the signals interfering with SaeS activity leading to inhibition of the sae target gene eap in strains with SaeS(L but causing activation in strains containing SaeS(P. Here, we analyzed the possible involvement of the SaeP protein and saePQ region in SDS-mediated sae/eap expression. We found that SaePQ is not needed for SDS-mediated SaeS signaling. Furthermore, we could show that SaeS activity is closely linked to the expression of Eap and the capacity to invade host cells in a number of clinical isolates. This suggests that SaeS activity might be directly modulated by structurally non-complex environmental signals, as SDS, which possibly altering its kinase/phosphatase activity.
Full Text Available The aim of the present study was to investigate the prevalence of S. aureus in raw sheep milk cheese and to assess the enterotoxigenic profile of the isolated strains. N.16 raw milk sheep cheese, collected from 8 artisan dairies, were analyzed to detect the presence of Coagulase Positive Staphylococci (CPS. In the frame of Regulation (EC No 2073/2005 cheese samples were tested for the presence of staphylococcal enterotoxins (SEs when a CPS count >105 cfu/g was detected. CPS isolates identified as S. aureus were analyzed using multiplex PCR for the detection of classical (sea-see and enterotoxins-like (seh, sek, sel, sem, seo, sep genes. S. aureus was recovered in all cheese samples and in 50% with levels >105 cfu/g. 14 strains carried at least one of the genes coding for enterotoxins. In none of the cheese samples SEs were detected. Although a correct acidification (pH 5.1-5.4 at 6 hours was observed in dairies using natural starter culture, in cheese samples obtained from these dairies, CPS counts were greater (P<0.05 as compared with those where starter culture were not used. This result might be related to the main role of microbial competition on the control of S. aureus in early stage of cheesemaking. Further research is needed to better understand the effect of lactic acid bacteria competition on the growth of S. aureus.
Ansari, Shamshul; Gautam, Rajendra; Shrestha, Sony; Ansari, Safiur Rahman; Subedi, Shankar Nanda; Chhetri, Muni Raj
Background Staphylococcus aureus (S. aureus), a normal flora of nasal cavity, can cause minor to life threatening invasive diseases and nosocomial infections. Methicillin resistant strains of S. aureus are causing a great challenge for treatment options. Therefore, the purpose of this study was to assess the nasal carriage rate of S. aureus, its methicillin resistant strains and risk factors in medical students prior to clinical exposure. Methods The bacterial growth of S. aureus from nasal s...
Full Text Available Abstract Background There has been considerable effort to discover plant-derived antibacterials against methicillin-resistant strains of Staphylococcus aureus (MRSA which have developed resistance to most existing antibiotics, including the last line of defence, vancomycin. Pentacyclic triterpenoid, a biologically diverse plant-derived natural product, has been reported to show anti-staphylococcal activities. The objective of this study is to evaluate the interaction between three pentacyclic triterpenoid and standard antibiotics (methicillin and vancomycin against reference strains of Staphylococcus aureus. Methods and Results The activity of the standard antibiotics and compounds on reference methicillin-sensitive and resistant strains of S. aureus were determined using the macrodilution broth method. The minimum inhibitory concentration (MIC of the compounds was compared with that of the standard antibiotics. The interaction between any two antimicrobial agents was estimated by calculating the fractional inhibitory concentration (FIC index of the combination. The various combinations of antibiotics and compounds reduced the MIC to a range of 0.05 to 50%. Conclusion Pentacyclic triterpenoids have shown anti-staphylococcal activities and although individually weaker than common antibiotics produced from bacteria and fungi, synergistically these compounds may use different mechanism of action or pathways to exert their antimicrobial effects, as implicated in the lowered MICs. Therefore, the use of current antibiotics could be maintained in their combination with plant-derived antibacterial agents as a therapeutic option in the treatment of S. aureus infections.
Pumarola, J; Berástegui, E; Canalda, C; Brau, E
The mean goal of this study is the determination of the conduct of 120 strains of Staphylococcus aureus against seven root canal sealers: Traitement Spad, Endométhasone, N2 Universal, AH26 with silver, Diaket-A, Tubli Seal and Sealapex. The agar diffusion test was employed in the determination of its bacterial growth inhibition. The results obtained have demonstrated values very different between the tested strains. Therefore we recommended to employ strains with reference in the investigation of the bacterial growth inhibition in order to repeat equal experimentation conditions. PMID:1659856
Full Text Available Essential oils extracted by microwave assisted hydrodistillation technique from Ocinum basilicum and Mentha piperita were characterized by GC-MS. An adapted diffusion method was used in order to assess the potentiator effect of the essential oils on the susceptibility of Staphylococcus aureus clinical and reference strains to some of the currently used antibiotics, i.e. clindamycin, ciprofloxacin, tetracycline, gentamicin, penicillin and erythromycin.. The Ocimum basilicum and Mentha piperita essential oils, exhibited a strong, strain specific influence on the antibiotic susceptibility of the tested strains.
Ghasemzadeh-Moghaddam, H; Neela, V; van Wamel, W; Hamat, R A; Shamsudin, M Nor; Hussin, N Suhaila Che; Aziz, M N; Haspani, M S Mohammad; Johar, A; Thevarajah, S; Vos, M; van Belkum, A
We performed a prospective observational study in a clinical setting to test the hypothesis that prior colonization by a Staphylococcus aureus strain would protect, by colonization interference or other processes, against de novo colonization and, hence, possible endo-infections by newly acquired S. aureus strains. Three hundred and six patients hospitalized for >7 days were enrolled. For every patient, four nasal swabs (days 1, 3, 5, and 7) were taken, and patients were identified as carriers when a positive nasal culture for S. aureus was obtained on day 1 of hospitalization. For all patients who acquired methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus via colonization and/or infection during hospitalization, strains were collected. We note that our study may suffer from false-negative cultures, local problems with infection control and hospital hygiene, or staphylococcal carriage at alternative anatomical sites. Among all patients, 22% were prior carriers of S. aureus, including 1.9% whom carried MRSA upon admission. The overall nasal staphylococcal carriage rate among dermatology patients was significantly higher than that among neurosurgery patients (n = 25 (55.5%) vs. n = 42 (16.1%), p 0.005). This conclusion held when the carriage definition included individuals who were nasal culture positive on day 1 and day 3 of hospitalization (p 0.0001). All MRSA carriers were dermatology patients. There was significantly less S. aureus acquisition among non-carriers than among carriers during hospitalization (p 0.005). The mean number of days spent in the hospital before experiencing MRSA acquisition in nasal carriers was 5.1, which was significantly lower than the score among non-carriers (22 days, p 0.012). In conclusion, we found that nasal carriage of S. aureus predisposes to rather than protects against staphylococcal acquisition in the nose, thereby refuting our null hypothesis. PMID:26183299
Full Text Available Background: Staphylococcus aureus is a major nosocomial pathogen world wide. Mupirocin plays a crucial role in strategies designed to control outbreaks of S. aureus. .Objectives: The aim of this study was to determine the frequency of mupirocin resistance in S. aureus strains isolated from nasal carriers among the hospitalized patients at Kermanshah Hospital, Iran..Patients and Methods: A total of 174 S. aureus isolates (sensitive and resistant to methicillin were collected from the nasal anterior nares of hospitalized patients. All isolates were tested for mupirocin susceptibility by a disc diffusion method. The minimum inhibitory concentration (MIC was determined by an E-test and they were also analyzed by a PCR for the presence of ileS-1 and ileS-2 genes..Results: Utilizing the disc diffusion agar method, E-test and PCR, all of the S. aureus strains tested were susceptible to mupirocin. In this study, the range of mupirocin MICs was determined to be between 0.064 and 4 μg/ml. There was a significant association between MIC observed and multi-drug resistant (MDR carriage (P value 0.04, and resistance to oxacillin (P value 0.004..Conclusions: This is a report of an initial survey of mupirocin resistance in S. aureus, in Kermanshah where the use of mupirocin is still limited. Perhaps the sensitivity of all isolates to mupirocin in this study is due to the less common usage of this antibiotic, especially in the form of nasal and site sample collections.
Full Text Available Strains of S. aureus were isolated from individual milk samples of 500 lacting cows from different areas in Slovakia (PH 1 - Košice region, 300 samples; PH 2 - Žilina region, 200 samples. The statistical significance between both dairy farms included in the experiment in the presence of genus Staphylococcus isolated on Baird-Parker agar from milk samples was p (*** . Totally, 122 milk samples were positive for the presence of Staphylococcus aureus (83 Košice regions, 52 Žilina regions. All 122 isolates of S. aureus were sensitive for the methicilin as detected by interpretative criteria developed by NCCLS (2002. For 122 S. aureus isolates, we compared antibiotic susceptibility results determined by the standardized agar diffusion assay with the PCR assay for the detection of antibiotic resistance mecA gene. For all isolates, we found a correlation between the results of the PCR and those of classical resistance testing. The obtained results were confirmed by PCR analysis, according to which, any of our tested isolate of S. aureus from all 122 individual milk samples from both experimental dairy farms were not positive for the presence of mecA gene coding the methicilin resistance. doi:10.5219/21
Juuti, Katri; Ibrahem, Salha; Virolainen-Julkunen, Anni; Vuopio-Varkila, Jaana; Kuusela, Pentti
pls, a gene found in type I staphylococcal cassette chromosome mec (SCCmec) regions of methicillin-resistant Staphylococcus aureus strains, was present in 12 of the 15 human clinical Staphylococcus sciuri isolates studied. Pls was expressed in the S. sciuri isolates, although at a lower level than in S. aureus. Other parts of SCCmec could also be found in the S. sciuri genome.
Murali, Thokur Sreepathy; Paul, Bobby; Parikh, Hersh; Singh, Rana Pratap; Kavitha, Shettigar; Bhat, Manoj K; Satyamoorthy, Kapaettu
Staphylococcus aureus is a major pathogen associated with diabetic foot ulcer infections. To gain insight into their pathogenicity and virulence potential, we report draft genome sequences of four strains of Staphylococcus aureus, isolated from diabetic foot ulcers, showing profiles with various degrees of resistance to common antibiotics.
Dan Mihaiescu; Crina Saviuc; Ioana Marinaş; Carmen Mariana Chifiriuc; Alexandru Mihai Grumezescu; Veronica Lazǎr
Essential oils extracted by microwave assisted hydrodistillation technique from Ocinum basilicum and Mentha piperita were characterized by GC-MS. An adapted diffusion method was used in order to assess the potentiator effect of the essential oils on the susceptibility of Staphylococcus aureus clinical and reference strains to some of the currently used antibiotics, i.e. clindamycin, ciprofloxacin, tetracycline, gentamicin, penicillin and erythromycin.. The Ocimum basilicum and Mentha piperit...
Sotto, Albert; Lina, Gérard; Richard, Jean-Louis; Combescure, Christophe; Bourg, Gisèle; Vidal, Laure; Jourdan, Nathalie; Etienne, Jérôme; Lavigne, Jean-Philippe
OBJECTIVE—The purpose of this study was to assess the virulence potential of Staphylococcus aureus strains isolated from diabetic foot ulcers and to discriminate noninfected from infected ulcers. RESEARCH DESIGN AND METHODS—Diabetic patients hospitalized in a diabetic foot department with a foot ulcer were prospectively enrolled if they had been free of antibiotic treatment over the previous 6 months. At admission, ulcers were classified as infected or noninfected on the basis of clinical exa...
Silva, Danielle Mendes; da Silva, Mônica Pacheco; Vidigal, Pedro M Pereira; Barcelos, Rafael Mazioli; Klein, Raphael Contelli; Aguilar, Ananda Pereira; Fabres-Klein, Mary Hellen; Oliveira, Guilherme; Ribon, Andréa Oliveira Barros
Here, we present the draft genome sequences of four Staphylococcus aureus strains isolated from mastitic milk collected from animals with subclinical manifestations. Three of them were typed as sequence type 126 (ST126), a genotype with no genome sequence available. ST126 is found in several herds of southern Brazil and is described as a bovine pathogen strongly associated with milk around the world. PMID:26893417
POUTREL, B.; Rainard, P; Sarradin, P.
It was reported previously that two capsular polysaccharides, types 5 and 8 (CP5 and CP8), account for 70 to 80% of Staphylococcus aureus strains isolated from human and animal sources. The capsular material has been shown to play a part in virulence and in resistance to phagocytosis. With a view to investigating the role that CP plays in pathogenicity or protection, relative measurement of cell-associated CP is desirable. Flow cytometry, which permits the analysis of individual bacteria, was...
Ouyang, Ping; Chen, Junjie; Sun, Mao; Yin, Zhongqiong; Lin, Juchun; Fu, Hualin; Shu, Gang; He, Changliang; Lv, Cheng; Deng, Xuming; Wang, Kaiyu; Geng, Yi; Yin, Lizi
Both community-associated and hospital-acquired infections with methicillin-resistant Staphylococcus aureus (MRSA) have been increasingly reported around the world in the past 20 years. In 2006, the Centers for Disease Control and Prevention reported that 64 % of MRSA isolates were of the USA300 clonal type in infected patients in USA. The aim of our study was to estimate the in vitro effect of imperatorin on MRSA strain BAA-1717 (USA300). The effects of imperatorin on alpha-hemolysin (Hla) production, when strain BAA-1717 was co-cultured with sub-inhibitory concentrations of imperatorin, were analysed using susceptibility testing, hemolysis assays, western blotting and real-time PCR. Live/Dead analysis and cytotoxicity assays were employed to examine the protective effect of imperatorin against the strain BAA-1717-mediated injury of human alveolar epithelial cells (A549). The results showed that imperatorin has no anti-S. aureus activity at the tested concentrations in vitro. However, imperatorin can observably inhibit the production of Hla in culture supernatants and reduce the transcriptional levels of hla (the gene encoding Hla) and arg (the accessory gene regulator). Imperatorin prevented Hla-mediated A549 epithelial cell injury in a co-culture system. In conclusion, our results suggested that imperatorin has the potential to be developed as a new anti-virulence drug candidate for managing S. aureus infection. PMID:27043440
Full Text Available Abstract Background Staphylococcus aureus is one of the most prevalent pathogens to cause mastitis in dairy cattle. Intramammary infection of dairy cows with S. aureus is often subclinical, due to the pathogen's ability to evade the innate defense mechanisms, but this can lead to chronic infection. A sub-population of S. aureus, known as small colony variant (SCV, displays atypical phenotypic characteristics, causes persistent infections, and is more resistant to antibiotics than parent strains. Therefore, it was hypothesized that the host immune response will be different for SCV than its parental or typical strains of S. aureus. In this study, the local and systemic immune protein responses to intramammary infection with three strains of S. aureus, including a naturally occurring bovine SCV strain (SCV Heba3231, were characterized. Serum and casein-depleted milk cytokine levels (interleukin-8, interferon-γ, and transforming growth factor-β1, as well as serum haptoglobin concentrations were monitored over time after intramammary infection with each of the three S. aureus strains. Furthermore, comparative proteomics was used to evaluate milk proteome profiles during acute and chronic phases of S. aureus intramammary infection. Results Serum IL-8, IFN-γ, and TGF-β1 responses differed in dairy cows challenged with different strains of S. aureus. Changes in overall serum haptoglobin concentrations were observed for each S. aureus challenge group, but there were no significant differences observed between groups. In casein-depleted milk, strain-specific differences in the host IFN-γ response were observed, but inducible IL-8 and TGF-β1 concentrations were not different between groups. Proteomic analysis of the milk following intramammary infection revealed unique host protein expression profiles that were dependent on the infecting strain as well as phase of infection. Notably, the protein, component-3 of the proteose peptone (CPP3, was
Ott, C. Mark; Castro, S. L.; Nickerson, C. A.; Nelman-Gonzalez, M.
Background: The opportunistic pathogen, Staphylococcus aureus, experiences fluctuations in fluid shear during infection and colonization of a human host. Colonization frequently occurs at mucus membrane sites such as in the gastrointestinal tract where the bacterium may experience low levels of fluid shear. The response of S. aureus to low fluid shear remains unclear. Methods: S. aureus was cultured to stationary phase using Rotating-Wall Vessel (RWV) bioreactors which produce a physiologically relevant low fluid shear environment. The bacterial aggregates that developed in the RWV were evaluated by electron microscopy as well as for antibiotic resistance and other virulence-associated stressors. Genetic expression profiles for the low-shear cultured S. aureus were determined by microarray analysis and quantitative real-time PCR. Results: Planktonic S. aureus cultures in the low-shear environment formed aggregates completely encased in high amounts of extracellular polymeric substances. In addition, these aggregates demonstrated increased antibiotic resistance indicating attachment-independent biofilm formation. Carotenoid production in the low-shear cultured S. aureus was significantly decreased, and these cultures displayed an increased susceptibility to oxidative stress and killing by whole blood. The hfq gene, associated with low-shear growth in Gram negative organisms, was also found to be down-regulated in S. aureus. Conclusions: Collectively, this data suggests that S. aureus decreases virulence characteristics in favor of a biofilm-dwelling colonization phenotype in response to a low fluid shear environment. Furthermore, the identification of an Hfq response to low-shear culture in S. aureus, in addition to the previously reported responses in Gram negative organisms, strongly suggests an evolutionarily conserved response to mechanical stimuli among structurally diverse prokaryotes.
Bonar, Emilia; Wojcik, Iwona; Jankowska, Urszula; Kedracka-Krok, Sylwia; Bukowski, Michal; Polakowska, Klaudia; Lis, Marcin W.; Kosecka-Strojek, Maja; Sabat, Artur J.; Dubin, Grzegorz; Friedrich, Alexander W.; Miedzobrodzki, Jacek; Dubin, Adam; Wladyka, Benedykt
Staphylococcus aureus is a commensal inhabitant of skin and mucous membranes in nose vestibule but also an important opportunistic pathogen of humans and livestock. The extracellular proteome as a whole constitutes its major virulence determinant; however, the involvement of particular proteins is still relatively poorly understood. In this study, we compared the extracellular proteomes of poultry-derived S. aureus strains exhibiting a virulent (VIR) and non-virulent (NVIR) phenotype in a chicken embryo experimental infection model with the aim to identify proteomic signatures associated with the particular phenotypes. Despite significant heterogeneity within the analyzed proteomes, we identified alpha-haemolysin and bifunctional autolysin as indicators of virulence, whereas glutamylendopeptidase production was characteristic for non-virulent strains. Staphopain C (StpC) was identified in both the VIR and NVIR proteomes and the latter fact contradicted previous findings suggesting its involvement in virulence. By supplementing NVIR, StpC-negative strains with StpC, and comparing the virulence of parental and supplemented strains, we demonstrated that staphopain C alone does not affect staphylococcal virulence in a chicken embryo model.
Full Text Available Background: Staphylococcus aureus is a gram positive coccus which is able to cause different kinds of infection in certain condition. The function of this bacteria is to provide the conditions for the invasion of it to the host with the secretion of different sorts of toxins such as Staphylococcus aureus enterotoxin, including important virulence factors that super antigens are all factors digestive inconvenience. Staphylococcus aureus enterotoxin-secreting toxins such conditions provides invasion of host genes. There are different types of SE, but type A enterotoxin (SEA and type B enterotoxin (SEB are the most important types. Therefore, in this study, the prevalence of Staphylococcus aureus toxin-producing enterotoxin genes (SEB, SEA in clinical strains isolated from patients in teaching hospitals of Shahrekord city, Iran, were studied. Methods: This cross-sectional and descriptive study, which was conducted from May 2014 to December 2014. A hundred and ten isolates of Staphylococcus aureus from patients collected over a period of 8 months and were first identified using standard biochemical methods and laboratory. Using standard methods and laboratory tests were identified and compared with the antibiotic oxacillin minimum inhibitory concentration were determined by broth micro dilution, and then they were assessed by polymerase chain reaction (PCR technique. Results: The results indicated that, 110 samples of dairy products infected by Staphylococcus aureus were detected. Two cases (1.8% of these infected samples were carrying both enterotoxin A and enterotoxin B genes. The frequencies of enterotoxin A genes were twenty-six cases (23/6% and The frequencies of enterotoxin B genes were two cases (1/8%, respectively. Conclusion: The detection of enterotoxin A and enterotoxin B genes, shows the most important role they have in bringing about superinfection. The detection of enterotoxin A and B genes, shows the most important role they have in
Schlenker, Gerd; Szabo, Istvan; Roesler, Uwe
Sensitivity to commercial teat dips (nonoxinol-9 iodine complex and chlorhexidine digluconate) of 56 Staphylococcus (S.) aureus strains isolated from quarter milk samples of various German dairy herds treated with different teat dipping schemes was investigated in this study. The minimum inhibitory concentration was determined using a broth macrodilution method according to the German Veterinary Association guidelines. The main objective of the current study was to induce in vitro resistance induction of S. aureus to chemical disinfectants. Ten different strains were repeatedly passed ten times in growth media with sub-lethal concentrations of disinfectants. Nine strains showed a significant reduction in susceptibility to the nonoxinol-9 iodine complex but only one strain developed resistance to chlorhexidine digluconate. Stability of the acquired resistance was observed in all S. aureus strains adapted to the nonoxinol-9 iodine complex and chlorhexidine digluconate. In contrast, simultaneous resistance to different antibiotics was not observed in any of the ten investigated S. aureus strains. However, the isolates exhibited a high degree of resistance to penicillin G. Based on these results, resistance of S. aureus to chemical disinfectants may be more likely to develop if the chemicals are used at concentrations lower than that required for an optimal biocidal effect. PMID:22705737
MRS926 is a livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) strain of sequence type (ST) 398. In order to facilitate in vitro and in vivo studies of this strain, we sought to tag it with a fluorescent marker. We cloned a codon-optimized gene for TurboGFP into a shuttle vector...
Wladyka, Benedykt; Wielebska, Katarzyna; Wloka, Marcin; Bochenska, Oliwia; Dubin, Grzegorz; Dubin, Adam; Mak, Pawel
Staphylococcus aureus strain CH-91, isolated from a broiler chicken with atopic dermatitis, has a highly proteolytic phenotype that is correlated with the disease. We describe the isolation and biochemical and molecular characterization of the AI-type lantibiotic BacCH91 from S. aureus CH-91 culture medium. The bacteriocin was purified using a three-stage procedure comprising precipitation with ammonium sulfate, extraction with organic solvents, and reversed-phase HPLC. The BacCH91 peptide is...
Melchior, M.B.; van Osch, M.H.J.; Graat, R.M.; van Duijkeren, E.; Mevius, D.J.; Nielen, M.; Gaastra, W.; Fink-Gremmels, J.
The increasing evidence for a role of biofilm formation in bovine mastitis caused by Staphylococcus aureus led to further investigations on biofilm formation by S. aureus isolates from mastitis in two growth media (TSBg and bovine milk serum). The ability of 99 S. aureus strains that were recently i
Melchior, M.B.; Osch, M.H.J.; Graat, R.; Duijkeren, van E.; Mevius, D.J.; Nielen, M.; Gaastra, W.; Fink, J.
The increasing evidence for a role of biofilm formation in bovine mastitis caused by Staphylococcus aureus led to further investigations on biofilm formation by S. aureus isolates from mastitis in two growth media (TSBg and bovine milk serum). The ability of 99 S. aureus strains that were recently i
Full Text Available Staphylococcus epidermidis and Staphylococcus aureus are currently considered two of the most important pathogens in nosocomial infections associated with catheters and other medical implants and are also the main contaminants of medical instruments. However because these species of Staphylococcus are part of the normal bacterial flora of human skin and mucosal surfaces, it is difficult to discern when a microbial isolate is the cause of infection or is detected on samples as a consequence of contamination. Rapid identification of invasive strains of Staphylococcus infections is crucial for correctly diagnosing and treating infections. The aim of the present study was to identify specific genes to distinguish between invasive and contaminating S. epidermidis and S. aureus strains isolated on medical devices; the majority of our samples were collected from breast prostheses. As a first step, we compared the adhesion ability of these samples with their efficacy in forming biofilms; second, we explored whether it is possible to determine if isolated pathogens were more virulent compared with international controls. In addition, this work may provide additional information on these pathogens, which are traditionally considered harmful bacteria in humans, and may increase our knowledge of virulence factors for these types of infections.
Karima G. Abdel Hameed
Full Text Available Aim: The aim was to investigate cheese samples for the prevalence of Staphylococcus aureus, evaluate multiplex polymerase chain reaction (PCR methods for S. aureus identification, as well as to determine the antibacterial activity of silver nanoparticles against such strains. Materials and Methods: Total of 100 random locally manufactured cheese samples were collected from Qena dairy markets, Egypt, and examined conventionally for the prevalence of S. aureus then, confirmation of these isolates were done using multiplex PCR. The antibacterial activity of silver nanoparticles against such isolates was also checked. Results: Lower prevalence of S. aureus in Damietta cheese (54% than in Kareish cheese (62% was recorded. As well lower frequency distribution for both S. aureus (36% and CNS (8% was also reported for Damietta cheese. Using of multiplex PCR method for S. aureus identification have been confirmed all 58 S. aureus stains that were identified conventionally by detection of two PCR products on agarose gel: The 791 bp and the 638 bp. The correlation coefficient between conventional and multiplex PCR method was 0.91 and was significant at p≤0.001. Regarding antibacterial activity of silver nanoparticles using disk diffusion method on Baird Parker agar it was found that inhibition zone of silver nanoparticles against S. aureus, was 19.2±0.91 mm and it was higher than that produced by gentamicin (400 units/ml 15.2±0.89 mm. Conclusions: The present study illustrated the higher prevalence of S. aureus in cheese samples that may constitute a public health hazard to consumers. According to the results, it can be concluded that silver nanoparticles can be used as an effective antibacterial against S. aureus. Thereby, there is a need for an appropriate study for using silver nanoparticles in cleaning and disinfection of equipment and in food packaging.
Djahmi, N; Messad, N; Nedjai, S; Moussaoui, A; Mazouz, D; Richard, J-L; Sotto, A; Lavigne, J-P
Staphylococcus aureus is the most common pathogen cultured from diabetic foot infection (DFI). The consequence of its spread to soft tissue and bony structures is a major causal factor for lower-limb amputation. The objective of the study was to explore ecological data and epidemiological characteristics of S. aureus strains isolated from DFI in an Algerian hospital setting. Patients were included if they were admitted for DFI in the Department of Diabetology at the Annaba University Hospital from April 2011 to March 2012. Ulcers were classified according to the Infectious Diseases Society of America/International Working Group on the Diabetic Foot classification system. All S. aureus isolates were analysed. Using oligonucleotide arrays, S. aureus resistance and virulence genes were determined and each isolate was affiliated to a clonal complex. Among the 128 patients, 277 strains were isolated from 183 samples (1.51 isolate per sample). Aerobic Gram-negative bacilli were the most common isolated organisms (54.9% of all isolates). The study of ecological data highlighted the extremely high rate of multidrug-resistant organisms (MDROs) (58.5% of all isolates). The situation was especially striking for S. aureus [(85.9% were methicillin-resistant S. aureus (MRSA)], Klebsiella pneumonia (83.8%) and Escherichia coli (60%). Among the S. aureus isolates, 82.2% of MRSA belonged to ST239, one of the most worldwide disseminated clones. Ten strains (13.7%) belonged to the European clone PVL+ ST80. ermA, aacA-aphD, aphA, tetM, fosB, sek, seq, lukDE, fnbB, cap8 and agr group 1 genes were significantly associated with MRSA strains (p <0.01). The study shows for the first time the alarming prevalence of MDROs in DFI in Algeria. PMID:23521557
Mashouf, Rasoul Y.; Seyed M. Hosseini; Arabestani, Mohammad R.
Objectives: The aims of our study were to evaluate the prevalence of Staphylococcus aureus (S. aureus) strains in food samples of animal origin, examine their antibacterial susceptibility pattern, and to detect staphylococcal enterotoxin (SEs) genes and the mecA gene in isolated S. aureus strains using the polymerase chain reaction (PCR). Methods: A total of 1050 food samples including 671 raw milk and dairy products and 379 raw meats were collected between September 2013 and June 2014 in Ham...
Cheng, Jinghua; Wang, Yan; Cao, Yongzhong; Yan, Wenguang; Niu, Xiaosai; Zhou, Liping; Chen, Jianhao; Sun, Ying; Li, Chenxi; Zhang, Xiaorong; Wu, Yantao
The distribution of 18 staphylococcal enterotoxin (SE) or SE-like (SEl) genes in Staphylococcus aureus strains from different sources in east China was investigated. Among all 496 S. aureus strains, 291 strains carried one or more SE genes. The more frequently occurred genes were sea, seb, seg, selk, sell, selm, selo, and seq; the less frequent occurred genes were sec, selj, and ser. The classic SE genes and the enterotoxin gene cluster (egc) (seg, sei, selm, seln, selo, and/or selu) accounted for 25.67% and 61.68% of all detected genes, respectively. There were three gene clusters (egc, sea-sek-seq, and sed-sej-ser), of which the egc cluster was the important one that could generate novel complexes, and the sea-sek-seq cluster was a close relative to the hospital-acquired methicillin-resistant S. aureus. The SE gene distributions were different among strains of different sources and formed diverse toxin gene profiles. The human- and foodborne-origin strains harbored classic and novel SE and SEl genes, whereas animal-origin strains harbored egc and other novel SE and SEl genes mainly. The foodborne- and human-origin strains were the main dangerous factors of classic staphylococcal foodborne poisoning, whereas the strains (especially from animals) that carried egc and other novel genes mainly should be new potential dangerous factors for food safety. PMID:27074376
Full Text Available The aim of the presented study was to examine in vitro the antibacterial activity of protocatechuic acid ethyl ester (ethyl 3,4-dihydroxybenzoate, EDHB against Staphylococcus aureus clinical isolates alone and in the combination with four selected antibiotics. The EDHB antimicrobial activity was tested against twenty S. aureus strains isolated from the clinical samples, and three reference strains. The phenotypes and genotypes of resistance to methicillin for the tested strains were defined as well as the phenotypic resistance to macrolides, lincosamides and streptogramin B (MLSB. EDHB displayed diverse activity against examined S. aureus strains with the minimal inhibitory concentration (MIC within the range from 64 to 1024 µg/mL. Addition of ¼ MIC of EDHB into the Mueller-Hinton Agar (MHA resulted in augmented antibacterial effect in the presence of clindamycin. In the case of cefoxitin no synergistic effect with EDHB was noted. For erythromycin and vancomycin the decrease of mean MICs in the presence of EDHB was observed but did not reach statistical significance. The results of the present study showed that in vitro EDHB possesses antibacterial activity against S. aureus clinical strains and triggers a synergistic antimicrobial effect with clindamycin and to the lesser extent with erythromycin and vancomycin.
Lv, GuoPing; Xu, BaoHong; Wei, PeiNan; Song, Jie; Zhang, HongYing; Zhao, Chuan; Qin, LiYun; Zhao, BaoHua
Staphylococcus aureus is an opportunistic pathogen commonly identified from food poisoning-associated foodstuffs. From 1996 to the present, S. aureus isolates have been found to exhibit increasing resistance to antimicrobial drugs. The aim of this study was to assess the molecular epidemiology properties of various S. aureus isolates through molecular typing and to investigate their characterization based on their production of enterotoxins and hemolysins and their resistance to antibiotics. A total of 78 coagulase-positive staphylococcal strains isolated from food or clinical samples were analyzed. Eight VNTR loci were used to genotype the 78 isolates, and this analysis resulted in 39 different multilocus variable number tandem repeat analysis (MLVA) profiles. The isolates recovered from a single outbreak exhibited the same MLVA profile. According to CLSI, 97.4% of the isolates were resistant to penicillin, whereas only 3.8% were methicillin-resistant Staphylococcus aureus strains. Through multiplex PCR, 87.2% of the isolates were shown to be enterotoxigenic (SEs), and the most common genes present were sea, sem, seg, seu, and sek. In conclusion, this study demonstrates the prevalence of staphylococcal enterotoxins, the contents of virulent factors, and the characteristics of β-lactam antibiotic resistance in 78 S. aureus isolates. These findings emphasize the need to prevent the presence of S. aureus strains and SE production in foods. Our results also demonstrate that MLVA is a useful and powerful method for epidemiological studies of S. aureus. In contrast to multilocus sequence typing, the MLVA method is a simpler and more rapid method for epidemiological typing with a higher discriminatory power. PMID:24582576
The present study aims to investigate the bactericidal activity (specifically antistaphylococcal) of Inula helenium. The antimicrobial activity of the extract is tested against 200 clinically significant Irish Staphylococcus aureus isolates consisting of methicillin-resistant (MRSA) and -sensitive (MSSA) S. aureus using a drop test method and a microbroth dilution method. The antibacterial effect is evaluated by measuring the area of the inhibition zone against the isolates. Results proved I. helenium to be 100% effective against the 200 staphylococci tested, with 93% of isolates falling within the ++ and +++ groups. The minimum bactericidal concentration of I. helenium was examined on a subset of isolates and values ranged from 0.9 mg\\/mL to 9.0 mg\\/mL. The extract was equally effective against antibiotic-resistant and -sensitive strains. This plant therefore possesses compounds with potent antistaphylococcal properties, which in the future could be used to complement infection control policies and prevent staphylococcal infection and carriage. This research supports other studies wherein herbal plants exhibiting medicinal properties are being examined to overcome the problems of antibiotic resistance and to offer alternatives in the treatment and control of infectious diseases.
Ghaleb Adwan; Mohammad Mhanna
Objective:This study has been done to evaluate the interaction between water extracts of Psidium guajava, Rosmarinus officinalis,Salvia fruticosa,Majorana syriaca,Ocimum basilucum,Syzygium aromaticum,Laurus nobilis,and Rosa damascena alone and then synergy testing of these extracts with known antimicrobial agents including oxytetracycline HCl,gentamicin sulfate,penicillin G,cephalexin and enrofloxacin.This study was conducted against five S.aureus isolates;one is Methicillin -resistant Staphylococcus aureus (MRSA)and 4 Methicillin -sensitive Staphylococcus aureus (MSSA).Methods:Evaluation of the interaction between plant extracts and different antimicrobial agents has been done using well -diffusion and microdilution methods. Results:The results of the conducted experiments using well -diffusion method demonstrate that these plants showed in vitro interactions between antimicrobial agents and plant extracts were additive,while using microdi-lution method showed synergistic effects with significant reduction in the MICs of the test antibiotics against these strains of S.aureus.This change in MIC was noticed in all plant extracts against test antibiotics inclu-ding these plants showed weak antibacterial activity by well diffusion method.Synergism effect was occurred in both sensitive and resistant strains but the magnitude of minimum fold reduction of inhibitory concentration in resistant strains especially MRSA strain was higher than the sensitive strains.Coclusion:This study probably suggests the possibility of concurrent use of these antimicrobial drugs and plant extracts in combination in trea-ting infections caused by S.aureus strains or at least the concomitant administration may not impair the antimi-crobial activity of these antibiotics.
Larner-Svensson, Hanna; Worning, Peder; Bartels, Mette;
We report the genome sequence, in five contigs, of a methicillin-resistant Staphylococcus aureus isolate designated M1. This clinical isolate was from the index patient of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak in Copenhagen, Denmark, that started in 2003. This strain is...
Aarestrup, Frank Møller; Wegener, Henrik Caspar; Rosdahl, V.T.
Fiftytwo strains of S. aureus isolated from cases of bovine subclinical mastitis in 52 different dairy herds in Denmark, in the peri ods 1952 to 1956 and 1992, were compared with regard to their phage- and EcoRI ribotypes. Furthermore, susceptibility to penicillin and production of fibrinolysin...
Ohtomo, T; Yamada, T; Yoshida, K.
The effects of drying time during freeze-drying on the outermost cell surface of an encapsulated strain of Staphylococcus aureus S-7 (Smith, diffuse) were investigated, with special attention paid to capsule and slime production. To quantify capsule and slime production, capsule antigen production and cellular characteristics such as growth type in serum-soft agar, cell volume index, and clumping factor reaction were examined. After freeze-drying the colonial morphology of strain S-7 was alte...
Chongtrakool, Piriyaporn; Ito, Teruyo; Ma, Xiao Xue; Kondo, Yoko; Trakulsomboon, Suwanna; Tiensasitorn, Chuntima; Jamklang, Mantana; Chavalit, Tavinun; Song, Jae-Hoon; Hiramatsu, Keiichi
A description of staphylococcal cassette chromosome mec (SCCmec) elements carried by 615 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in 11 Asian countries is reported, and a novel nomenclatural system based on their structures is proposed. The 615 strains were classified as type 3A (370 strains), type 2A (207 strains), type 2B (32 strains), type 1B (1 strain), and nontypeable (5 strains). The previously reported type III SCCmec (DDBJ/EMBL/GenBank accession no. AB037671...
Full Text Available Research objective is to study antibacterial action of nanoparticles of iron and copper on polyantibiotically resistant clinical Staphylococcus aureus strains. Materials and methods include antibacterial action of nanoparticles of copper and iron on 10 Staphylococcus au¬reus strains, isolated from patients with purulent complications stayed in the in-patient department of traumatology and orthopedics. Solutions of powders of iron and copper have been prepared directly before the experiment in concentra¬tion from 0,001 to 1 mg/ml. it has been revealed that the influence of nanoparticles on growth of clinical strains and the intensity of antibacterial effect depends on the form of nanoparticles, their concentration and action time. concentration of 0,1 mg/ml and 1 mg/ ml of iron nanoparticles has provoked the decrease in quantity of microbe cells from 3 to 34 % (p <0,01. in smaller concentrations the reliable antibacterial effect has not been observed. Antibacterial activity of copper nanoparticles has been expressed in a wide range of concentrations from 0,001 mg/ml to 1 mg/ml, even during short-term action (30 minutes it has provoked reduction of quantity of the microbe cells grown on the firm nutrient medium, 97-100 % in comparison with the control (p <0,001. in conclusion it is to point out that copper nanoparticles have more expressed inhibitory effect on growth of clini��cal strains of golden staphylococcus than iron nanoparticle suspension. inhibition degree depends on superdispersed powder dosage and incubation period
D'amico, Dennis J; Donnelly, Catherine W
Staphylococcus aureus is an important agent of bacterial mastitis in milking animals and of foodborne intoxication in humans. The purpose of this study was to examine the genetic and phenotypic diversity, enterotoxigenicity, and antimicrobial resistance of S. aureus strains isolated from raw milk used for the production of artisan cheese in Vermont. Cross-tabulations revealed that the 16 ribotypes identified among the 90 milk isolates examined were typically associated with a specific animal species and that more than half of these ribotypes were unique to individual farms. In general, specific EcoRI ribotypes were commonly associated with specific phenotypical characteristics, including staphylococcal enterotoxin production or the lack thereof. Limited antimicrobial resistance was observed among the isolates, with resistance to ampicillin (12.51%) or penicillin (17.04%) most common. Two isolates of the same ribotype obtained from the same farm were resistant to oxacillin with 2% NaCl. More than half (52.22%) of isolates produced toxin, and 31 of the 32 isolates solely produced staphylococcal enterotoxin type C. Although these data demonstrate that S. aureus strains found in raw milk intended for artisan cheese manufacture are capable of enterotoxin production, staphylococcal enterotoxin C is not typically linked to foodborne illness. Because S. aureus is a common contaminant of cheese, an understanding of the ecology of this pathogen and of the antimicrobial susceptibility and toxigenicity of various strains will ultimately contribute to the development of control practices needed to enhance the safety of artisan and farmstead cheese production. PMID:21819666
Aarestrup, Frank Møller; Wegener, Henrik Caspar; Rosdahl, V.T.
Fiftytwo strains of S. aureus isolated from cases of bovine subclinical mastitis in 52 different dairy herds in Denmark, in the peri ods 1952 to 1956 and 1992, were compared with regard to their phage- and EcoRI ribotypes. Furthermore, susceptibility to penicillin and production of fibrinolysin...... were used as additional phenotypic markers. Fortynine strains (94%) could be separated into 12 phage types. Ribotyping assigned the 52 strains to 21 different types. Both methods showed that 57% of the 1950's strains and between 38-45% of the 1992 strains belonged to 3 dominating types. The remaining...... differences. Penicillin resistance only occurred in a single genotype from the 1950's compared to 6 different genotypes among the 1992 strains....
Strommenger, B; Braulke, C; Pasemann, B; Schmidt, C; Witte, W
The continuous spread of community-acquired methicillin-resistant Staphylococcus aureus (caMRSA) and the introduction of these highly virulent isolates into hospitals represent increasing threats. The timely recognition of caMRSA strains is crucial for infection control purposes. Thus, we developed a PCR-based assay for the easy and rapid determination of those caMRSA clones that currently are the most prevalent in Germany and Central Europe. This assay was able to correctly identify the majority of the isolates as caMRSA of sequence type 80 (ST80), clonal complex 1 (USA400), and ST8 (USA300). In combination with spa typing-BURP (based upon repeat pattern) analysis and resistance typing, it provides a means for the extensive characterization of suspicious isolates. Thus, this assay represents a reliable tool for monitoring the emergence and spread of different caMRSA clones. The resulting information, in combination with careful interpretation of the epidemiological records, might help to prevent the further spread of those highly virulent caMRSA clones. PMID:18032620
Behiry, Ayman El; Schlenker, Gerd; Szabo, Istvan; Roesler, Uwe
Sensitivity to commercial teat dips (nonoxinol-9 iodine complex and chlorhexidine digluconate) of 56 Staphylococcus (S.) aureus strains isolated from quarter milk samples of various German dairy herds treated with different teat dipping schemes was investigated in this study. The minimum inhibitory concentration was determined using a broth macrodilution method according to the German Veterinary Association guidelines. The main objective of the current study was to induce in vitro resistance ...
Wang, Shu-Hua; Hines, Lisa; van Balen, Joany; José R Mediavilla; Pan, Xueliang; Hoet, Armando E; Kreiswirth, Barry N.; Pancholi, Preeti; Stevenson, Kurt B.
Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are classified epidemiologically as health care-associated hospital onset (HAHO)-, health care-associated community onset (HACO)-, or community-associated (CA)-MRSA. Clinical and molecular differences between HAHO- and HACO-MRSA BSI are not well known. Thus, we evaluated clinical and molecular characteristics of MRSA BSI to determine if distinct features are associated with HAHO- or HACO-MRSA strains. Molecular ge...
Růzicková, Vladislava; Karpísková, Renata; Pantůcek, Roman; Pospísilová, Markéta; Cerníková, Pavla; Doskar, Jirí
Twenty-eight enterotoxin H-positive Staphylococcus aureus strains isolated from food samples collected in eleven districts of the Czech Republic between 2000 and 2005 were genotypically characterized by pulsed-field gel electrophoresis (PFGE) profiling, spa gene polymorphism analysis, enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) fingerprinting and prophage carriage detection. These strains accounted for about 21% of the food-derived, staphylococcal enterotoxin (SE)-positive isolates. One strain, detected in feta cheese, was implicated in a case of enterotoxinosis. Sixteen of the twenty-eight isolates carried the seh gene alone. The remaining twelve strains harbored the seh gene in combination with other enterotoxin genes, most often the seg and sei genes, followed by the sea, seb, sec and sed genes. Comparison of various genomic profiles resulted in the determination of twenty genotypes designated G-1 to G-20. Two new, to date not defined, spa types (t2000 and t2002) were identified in one strain isolated from raw meat and two strains obtained from prepacked pizza. Evidence has been given that the seh-positive S. aureus isolates from foodstuffs did not originate from a single source or a common ancestor. PMID:18054105
Lozano, Carmen; García-Migura, Lourdes; Aspiroz, Carmen; Zarazaga, Myriam; Torres, Carmen; Aarestrup, Frank Møller
An expansion of a previously described plasmid classification was performed and used to reveal the plasmid content of a collection of 92 Staphylococcus aureus strains of different origins. rep genes of other genera were detected in Staphylococcus. S1 pulsed-field gel electrophoresis (PFGE) hybridizations were performed with 18 representative S. aureus strains, and a high number of plasmids of different sizes and organizations were detected.
Østergaard, Claus; Grønvall Kjær Hansen, Sanne; Møller, Jens K
Fast and reliable discrimination of methicillin-resistant Staphylococcus aureus (MRSA) isolates is essential in identifying an outbreak. Molecular typing methods, such as S. aureus protein A (spa) typing, multi locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE) are generally...
M. Pujol (Miquel); C. Pena; R. Pallares (Roman); J. Ariza (Javier); J. Ayats (Josefina); M.A. Dominguez; F. Gudiol (Francesc)
textabstractObjectives To determine the relevance of nasal carriage of Staphylococcus aureus, either methicillin-sensitive (MSSA) or methicillinresistant (MRSA), as a risk factor for the development of nosocomial S aureus bacteremia during an MRSA outbreak. patients and methods: In this prospective
Antibiotic activity of the extract of Punica granatum Linn. over bovine strains of Staphylococcus aureus Atividade antimicrobiana do extrato de Punica granatum Linn. em linhagens de Staphylococcus aureus de origem bovina
Maria A. R. Silva; Jane S. Higino; Jozinete V. Pereira; José P. Siqueira-Júnior; Maria S.V. Pereira
Human and veterinary medicines have not been so well succeeded in order to achieving their goals concerning the treatment of infections for long term caused by Staphylococcus aureus linked to resistance development against antibiotic agents. The antibiotic activity of the Punica granatum Linn. fresh fruit pericarp extract was evaluated by the agar diffusion method on 38 S. aureus strains, isolated from apparently healthy lactating cows in farms situated in counties of the semi-arid region of ...
Eriksen, N H; Hartzen, S H; Bangsborg, Jette Marie;
During the period 1961-91 a total of 567,635 strains of Staphylococcus aureus from hospitalized patients in Denmark have been characterized according to their antibiotic resistance, site of isolation and phage type. Strains of phage group II (typed by the phages 3A, 3C, 55 and 71) have been...... analysed further. The occurrence of group II strains was relatively constant (approximately 16%) from 1961 until 1983. Since then the frequency of group II strains increased; in 1991 they accounted for 22.7% of all S. aureus strains isolated. Strains of group II can, on the basis of their phage types......, be divided in four subgroups: 3A, 71, 71+ and the 'rest of group II'. Furthermore, within these groups strains may differ from one another in respect to their sensitivity to phages. The increased isolation of group II strains during recent years was because of an increase in strains of subgroups 71...
Yan, Xiaomei; Wang, Bing; Tao, Xiaoxia; Hu, Qinghua; Cui, Zhigang; Zhang, Jianzhong; Lin, Yiman; You, Yuanhai; Shi, Xiaolu; Grundmann, Hajo
To characterize isolates of Staphylococcus aureus that were associated with staphylococcal food poisoning between 2006 and 2009 in Shenzhen, Southern China, a total of 52 Staphylococcus aureus isolates from 11 outbreaks were analyzed by using multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE). PCR analysis was used to analyze the staphylococcal enterotoxin (SE) genes sea to sei, and antimicrobial susceptibility testing was also performed. ST6 was the mo...
R. Kasra Kermanshahi
Full Text Available Nowadays, the multiple drug resistance and resistance to different antimicrobial are observed in a wide variety of bacteria. One of these agents is U.V. ray that sometimes used to sterilize the operation room space and utensils and gamma ray to sterilize some medical Instruments such as disposal syringes & cottons and etc. If resistance emerges against the above mentioned factor, fighting microbs by these factors will encounter more problems.Therefore, In this research the multiple resistance of pathogenic strains of S. aureus isolated from different infections were studied. The M.I.C and M.B.C to penicillins were determined, using dilution tube method and plate cultured respectively. The influence of U.V ray on the growth of bacteria under hood of laminator flow was measured by photon-meter, during different times (0, 30, 60, 120, 240 Sec at intensity of radiation 0.25 J/m2.S-1. The study of gamma ray on the growth of these bacteria were done by Iridium 192 source projector sentinel 660 as a gamma ray generator. Gamma irradiation was used at the intensity of 20 Gy/min and with dose of 500, 750 and 1000 Gray. The statistical study of the results obtained in different experiments was processed using S.A.S software. The standard strains were used as control and comparison.In these results, the strains of S. aureus showed maximum and minimum of MIC = 0.125% - 65 µg/ml and MBC = 1-128 µg/ml, respectively. For the study of bacterial level of resistance to U.V. ray, The most important resistance strains to antibiotics have been selected. The mean number of the colonies grown in the culture medium area after 120 and 240 seconds of U.V. radiation were Log N/No = 21.8, 6.9 respectively in the strain of Staphylococcus.Resistance of isolated strains of S. aureus in this research was higher than those of standard strains.
Saulnier, P; Bourneix, C; Prévost, G; Andremont, A
Twenty-six strains of methicillin-resistant Staphylococcus aureus with different pulsed-field gel electrophoresis fingerprints were tested by random amplified polymorphic DNA assay with three primers, resulting in 15 to 20 different random amplified polymorphic DNA fingerprints. By summing the results for the three primers, the number of different fingerprints increased to 25, but two strains could not be differentiated. We conclude that pulsed-field gel electrophoresis remains the best method of typing methicillin-resistant S. aureus strains. PMID:8463406
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens which can cause a broad spectrum of infections. Objectives: The current study aimed to describe the frequency and antibiotic susceptibility patterns of clonal groups of gentamicin-resistant strains of MRSA isolated from a tertiary care hospital in Tehran, Iran. Materials and Methods: A total of 301 S. aureus isolates were collected during January to November 2012. All of the isolates ...
Rahimi, Fateh; Shokoohizadeh, Leili
Methicillin resistant Staphylococcus aureus is one of the most common causes of a variety of infections ranging from wound infections to urinary tract infections (UTI) in hospital and community. In this study during 3 years we characterized the antibiotic resistance patterns of 491 hospital acquired MRSA and community associated MRSA strains by the guidelines of clinical and laboratory standard institute. A combination of high resolution PhP typing method and SCCmec typing were used for clonal dissemination of isolates. Among all 491 MRSA strains, diverse PhP types consisting of 29 common types (CTs) and 4 single types (STs) and also 2 different SCCmec types (III and IVa) were detected. In addition, 18 CTs were common among CA- and HA-MRSA strains and the presence of all 4 STs was limited to HA-MRSA strains. All isolates were resistant to penicillin and high level resistance was observed against ciprofloxacin, erythromycin, tobramycin and kanamycin and the rate of resistance to most of the antibiotic tested among HA-MRSA was significantly higher than CA-MRSA isolates. Moreover, all isolates showed susceptibility to linezolid, vancomycin and quinupristin-dalfopristin and very low resistance to fusidic acid, nitrofurantoin and chloramphenicol were detected. Our findings illustrated the increasing rate of clonal dissemination and persistence of highly antibiotic resistant CA-MRSA strains in Tehran hospitals, and also indicated the important role of the hospitals as the reservoir of MRSA strains. PMID:27265678
Lee, John Hwa
From May 2001 to April 2003, various types of specimens from cattle, pigs, and chickens were collected and examined for the presence of methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA). S. aureus was isolated and positively identified by using Gram staining, colony morphology, tests for coagulase and urease activities, and an API Staph Ident system. Among 1,913 specimens collected from the animals, 421 contained S. aureus; of these, 28 contained S. aureus resistant to concentrations of oxacillin higher than 2 micro g/ml. Isolates from 15 of the 28 specimens were positive by PCR for the mecA gene. Of the 15 mecA-positive MRSA isolates, 12 were from dairy cows and 3 were from chickens. Antimicrobial susceptibility tests of mecA-positive MRSA strains were performed by the disk diffusion method. All isolates were resistant to members of the penicillin family, such as ampicillin, oxacillin, and penicillin. All isolates were also susceptible to amikacin, vancomycin, and trimethoprim-sulfamethoxazole. To determine molecular epidemiological relatedness of these 15 animal MRSA isolates to isolates from humans, random amplified polymorphic DNA (RAPD) patterns were generated by arbitrarily primed PCR. The RAPD patterns of six of the isolates from animals were identical to the patterns of certain isolates from humans. The antibiotypes of the six animal isolates revealed types similar to those of the human isolates. These data suggested that the genomes of the six animal MRSA isolates were very closely related to those of some human MRSA isolates and were a possible source of human infections caused by consuming contaminated food products made from these animals. PMID:14602604
Šalplachta, Jiří; Růžička, F.; Horká, Marie
2015. s. 210-210. [International Conference on Instrumental methods of Analysis: Modern Trends and Applications /9./. 20.09.2015-24.09.2015, Kalamata] R&D Projects: GA MV VG20112015021; GA MV VG20102015023 Institutional support: RVO:68081715 Keywords : MALDI-TOF MS * S. aureus * MSSA and MRSA differentiation Subject RIV: CB - Analytical Chemistry, Separation
Heijer, C.D.J. den; Bijnen, E.M.E. van; Paget, W.J.; Stobberingh, E.E.
Aim: To evaluate fusidic acid resistance pheno- and geno-typically in nasal carriage Staphylococcus aureus isolated from general practice patients in nine European countries. Materials & methods: Phenotypic fusidic acid resistance was determined by disc diffusion and MIC values, and genotypically by
Heijer, C.D. den; Bijnen, E.M. van; Paget, W.J.; Stobberingh, E.E.
AIM: To evaluate fusidic acid resistance pheno- and geno-typically in nasal carriage Staphylococcus aureus isolated from general practice patients in nine European countries. MATERIALS & METHODS: Phenotypic fusidic acid resistance was determined by disc diffusion and MIC values, and genotypically by
Henrique D. M. Coutinho
Full Text Available Introduction: Combining multiple drugs is an strategy used to combat the dissemination of pathogenic and drug resistant bacteria. However, the misuse of these drugs against bacteria have caused the selection of more resistant specimens called multidrug-resistant bacteria. Objective: In this work we evaluated the antibiotic activity of claritromicin, gentamicin, ciprofloxacin and imipenen, alone or associating one by one, against strains of Escherichia coli and Staphylococcus aureus. Material and methods: The minimal inhibitory concentration (mic was performed using the microdilution assay. Based in the mic values, the antibiotic effect of the drugs alone and in association were determined. Results: The association between the drugs demonstrated the synergism against the bacterial strains. Conclusion: The use of the combined antibiotic-therapy can be positively performed, but additional studies have to be conducted first for proving that its use is safe.
Ballhausen, Britta; Kriegeskorte, André; Schleimer, Nina; Peters, Georg; Becker, Karsten
In staphylococci, methicillin resistance is mediated by mecA-encoded penicillin-binding protein 2a (PBP2a), which has a low affinity for beta-lactams. Recently, a novel PBP2a homolog was described as being encoded by mecC, which shares only 70% similarity to mecA. To prove that mecC is the genetic determinant that confers methicillin resistance in Staphylococcus aureus, a mecC knockout strain was generated. The S. aureus ΔmecC strain showed considerably reduced oxacillin and cefoxitin MICs (0.25 and 4 μg/ml, respectively) compared to those of the corresponding wild-type methicillin-resistant S. aureus (MRSA) strain (8 and 16 μg/ml, respectively). Complementing the mutant in trans with wild-type mecC restored the resistance to oxacillin and cefoxitin. By expressing mecC and mecA in different S. aureus clonal lineages, we found that mecC mediates resistance irrespective of the genetic strain background, yielding oxacillin and cefoxitin MIC values comparable to those with mecA. In addition, we showed that mecC expression is inducible by oxacillin, which supports the assumption that a functional beta-lactam-dependent regulatory system is active in MRSA strains possessing staphylococcal cassette chromosome mec (SCCmec) type XI. In summary, we showed that mecC is inducible by oxacillin and mediates beta-lactam resistance in SCCmec type XI-carrying strains as well as in different S. aureus genetic backgrounds. Furthermore, our results could explain the comparatively low MICs for clinical mecC-harboring S. aureus isolates. PMID:24752255
Ben Bacha, Abir; Moubayed, Nadine Ms; Al-Assaf, Alaa
In this study, a new strain, ALA1, was identified as Staphylococcus aureus by biochemical tests, and its 16S ribosomal DNA sequence was isolated from dromedary milk. ALA1 lipase production was optimized in shake flask experiments and measured with varying pH (3-11), temperature (20-55 °C) and substrate concentrations. The maximum lipase production was recorded at pH 8 and 30 °C for up to 30 H of culture period for the S. aureus ALA1 strain. Among the substrates tested, selected carbon sources, xylose, nitrogen source, yeast extract, and olive oil (1%) were suitable for maximizing lipase production. The effects of surfactants were investigated and showed that Tween 20, Tween 80, and Triton X-100 prevented lipase production. Interestingly, isolate ALA1 was able to grow in high concentrations of benzene or toluene (up to 50% (v/v)). Moreover, the lipolytic activity of the S. aureus ALA1 lipase was stimulated by diethyl ether, whereas almost 100% of S. aureus ALA1 lipase activity was retained in 25% acetone, acetonitrile, benzene, 2-propanol, ethanol, methanol, or toluene. Because of its stability in organic solvent, the S. aureus ALA1 lipase was used as a biocatalyst to synthesize high levels of added value molecules. S. aureus ALA1 lipase could be considered as an ideal choice for applications in detergent formulations because of its high stability and compatibility with various surfactants, oxidizing agents, and commercial detergents. PMID:25828848
Pellegrino, MS; Frola, ID; Odierno, LM; Bogni, CI
ResumenLa mastitis bovina es considerada la enfermedad infecciosa del ganado lechero de mayor impacto económico mundial, siendo Staphylococcus aureus el principal agente patógeno en muchos países.SummaryBovine mastitis is a frequent cause of economic loss in worldwide dairy herds, being Staphylococcus aureus the main etiological agent in many countries.
Full Text Available ResumenLa mastitis bovina es considerada la enfermedad infecciosa del ganado lechero de mayor impacto económico mundial, siendo Staphylococcus aureus el principal agente patógeno en muchos países.SummaryBovine mastitis is a frequent cause of economic loss in worldwide dairy herds, being Staphylococcus aureus the main etiological agent in many countries.
Full Text Available The cassette chromosome mec (SCCmec present in methicillin-resistant Staphylococcus aureus (MRSA has two essential components, the ccr gene complex and the mec gene complex. Additionally, SCCmec has non-essential components called J regions which are used for MRSA subtyping. This study was performed to determine subtypes MRSA strains carrying SCCmec type I based on polymorphism of regions located downstream of the mecA gene. A total of 98 MRSA strains carrying SCCmec type I isolated from patients hospitalized at the County Hospital of Valdivia (Chile between May 2007 and May 2008, were analyzed by multiplex PCR designed to amplify the mecA gene and 7 DNA hypervariable regions located around the mecA gene. MRSA strains were classified into seventeen genotypes accordingly to amplification patterns of DNA hypervariable regions. Five genotypes showed amplification patterns previously described. The remaining twelve genotypes showed new amplification patterns. Genotypes 18 and Genotype 19 were the most frequently detected. Regions HVR, Ins117 and pI258 stand out as being present in more than 60% of tested isolates. The acquisition of hypervariable regions by MRSA is a continuous horizontal transfer process through which the SCCmec have been preserved intact, or even may give rise to new types and subtypes of SCCmec. Therefore it is possible to infer that most MRSA strains isolated at the County Hospital of Valdivia (Chile were originated from two local clones which correspond to Genotype 18 and Genotype 19.
Tenover, Fred C; Sinner, Scott W; Segal, Robert E; Huang, Vanthida; Alexandre, Shandline S; McGowan, John E; Weinstein, Melvin P
Following an initial response to vancomycin therapy, a patient with meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia developed endocarditis, failed a second course of vancomycin and then failed daptomycin therapy. An increase in the vancomycin minimum inhibitory concentrations of four consecutive MRSA blood isolates from 2 microg/mL to 8 microg/mL was shown by Etest. Population analysis of four successive blood culture isolates recovered over the 10-week period showed that the MRSA strain became progressively less susceptible to both vancomycin and daptomycin. Retrospectively, the macro Etest method using teicoplanin indicated a decrease in vancomycin susceptibility in the second blood isolate. The patient improved after treatment with various courses of trimethoprim/sulfamethoxazole, quinupristin/dalfopristin and linezolid. Early detection of vancomycin-heteroresistant S. aureus isolates, which appeared to have clinical significance in this case, continues to be a challenge for the clinical laboratory. Development of suitable practical methods for this should be given priority. Concurrent development of resistance to vancomycin and daptomycin, whilst rare, must be considered in a patient who is unresponsive to daptomycin following vancomycin therapy. PMID:19233622
Lozano, C.; Garcia-Migura, L.; Aspiroz, C.;
An expansion of a previously described plasmid classification was performed and used to reveal the plasmid content of a collection of 92 Staphylococcus aureus strains of different origins. rep genes of other genera were detected in Staphylococcus. S1 pulsed-field gel electrophoresis (PFGE) hybrid...
Saulnier, P; Bourneix, C; Prévost, G; Andremont, A
Twenty-six strains of methicillin-resistant Staphylococcus aureus with different pulsed-field gel electrophoresis fingerprints were tested by random amplified polymorphic DNA assay with three primers, resulting in 15 to 20 different random amplified polymorphic DNA fingerprints. By summing the results for the three primers, the number of different fingerprints increased to 25, but two strains could not be differentiated. We conclude that pulsed-field gel electrophoresis remains the best metho...
Full Text Available ABSTRACT Background and objective: Todays, the resistance to antibiotics among of pathogen bacteria is one of the main concerns of doctors all around the world, with consideration to different reports about Staphylococcus aureus bacteria’s sensitivity, this study was done to examine the pattern of sensitivity and antibiotic resistance of Staphylococcus aureus strains collected from clinical samples of patients hospitalized in Tehran’s Araad hospital. Materials and methods: In this descriptive examination, after extracting Staphylococcus aureus derivations from clinical samples (urine, catheter, phlegm, wound, bronchial and blood, their sensitivity was measured using standard Kirby-Bauer test, in contract with following antibiotics Amikacin, Ciprofloxacin, Vancomycin, Imipenem, Sulfametoxazole Trimetoprime, Tetracycline, Oxacillin, Ceftriaxone and Penicillin. Results: In this study 260 samples of Staphylococcus aureus isolated from clinical specimens in three years. The most sensivity was to Vancomycin and the most resistance was to Penicillin and Oxacillin. Conclusion: The results of this study are indicating that Staphylococcus aureus strains resistance has increased against Penicillin and Oxacillin; presumably it is due to excessive consumption of these antibiotics. It is obvious that, with regard to increasing consumption of antibiotics and consequently, augmentation of antibacterial resistance, control of this resistance factor is necessary and inevitable, so it is recommended to avoid unnecessary usage of antibiotics.
Lee, John Hwa
From May 2001 to April 2003, various types of specimens from cattle, pigs, and chickens were collected and examined for the presence of methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA). S. aureus was isolated and positively identified by using Gram staining, colony morphology, tests for coagulase and urease activities, and an API Staph Ident system. Among 1,913 specimens collected from the animals, 421 contained S. aureus; of these, 28 contained S. aureus resistant to concentrat...
We report a study of 35 methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates collected between February and May 1998 from 4 different hospitals in Northern and Southern Palestine. The isolates were recovered from infection and carriage sites of patients and hospital environmental samples. The arbitrarily primed PCR (AP-PCR) method with two primers appears to be a useful tool, provides a fast and simple method for genetic analysis of MRSA infections and allows us to differentiate 22 different AP-PCR patterns. The major cluster, however, sharing common AP-PCR as well as a common PFGE pattern, represented 34% of all MRSA isolates. Isolates of these clusters were spread throughout the neonatal and intensive care units of Rafidya hospital during the entire period. In addition, these isolates were distributed in the southern part of Palestine as well. (author)
Brouillette, Eric; Hyodo, Mamoru; Hayakawa, Yoshihiro; Karaolis, David K.R.; Malouin, François
The cyclic dinucleotide 3′,5′-cyclic diguanylic acid (c-di-GMP) is a naturally occurring small molecule that regulates important signaling systems in bacteria. We have recently shown that c-di-GMP inhibits Staphylococcus aureus biofilm formation in vitro and its adherence to HeLa cells. We now report that c-di-GMP treatment has an antimicrobial and antipathogenic activity in vivo and reduces, in a dose-dependent manner, bacterial colonization by biofilm-forming S. aureus strains in a mouse mo...
El-Guendouz, Soukaina; Aazza, Smail; Lyoussi, Badiaa; Bankova, Vassya; Lourenço, João P; Costa, Ana M Rosa; Mariano, José F; Miguel, Maria G; Faleiro, Maria L
Biofilm bacteria are more resistant to antibiotics than planktonic cells. Propolis possesses antimicrobial activity. Generally, nanoparticles containing heavy metals possess antimicrobial and antibiofilm properties. In this study, the ability of adherence of Methicillin Resistant Strains of Staphylococcus aureus (MRSA) to catheters treated with magnetite nanoparticles (MNPs), produced by three methods and functionalized with oleic acid and a hydro-alcoholic extract of propolis from Morocco, was evaluated. The chemical composition of propolis was established by gas chromatography mass spectrometry (GC-MS), and the fabricated nanostructures characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Mossbauer spectroscopy and Fourrier transform infrared spectroscopy (FTIR). The capacity for impairing biofilm formation was dependent on the strain, as well as on the mode of production of MNPs. The co-precipitation method of MNPs fabrication using Fe(3+) and Na₂SO₃ solution and functionalized with oleic acid and propolis was the most effective in the impairment of adherence of all MRSA strains to catheters (p < 0.001). The adherence of the strain MRSA16 was also significantly lower (p < 0.001) when the catheters were treated with the hybrid MNPs with oleic acid produced by a hydrothermal method. The anti-MRSA observed can be attributed to the presence of benzyl caffeate, pinocembrin, galangin, and isocupressic acid in propolis extract, along with MNPs. However, for MRSA16, the impairment of its adherence on catheters may only be attributed to the hybrid MNPs with oleic acid, since very small amount, if any at all of propolis compounds were added to the MNPs. PMID:27618006
Pereira, Gilmar Ferreira; McGugan, Malcolm; Mikkelsen, Lars Pilgaard
A novel method to obtain independent strain and temperature measurements using embedded Fibre Bragg Grating (FBG) in polymeric tensile test specimens is presented in this paper. The FBG strain and temperature cross-sensitivity was decoupled using two single mode FBG sensors, which were embedded in....... Equations to calculate independently the strain and temperature are presented in the article, together with a measurement resolution study. This multi-parameter measurement method was applied to an epoxy tensile specimen, tested in a unidirectional tensile test machine with a temperature controlled cabinet...... variation of temperature, from 40 C to -10 C. The consistency of the expected theoretical results with the calibration procedure and the experimental validation shows that this proposed method is applicable to measure accurate strain and temperature in polymers during static or fatigue tensile testing. Two...
Mukherjee, Sandipan; Ramesh, Aiyagari
In the present study, the adhesion of bacteriocin-producing probiotic strains of Lactobacillus plantarum onto extracellular matrix (ECM) proteins such as collagen and mucin and their potential to prevent pathogen invasion onto the ECM was ascertained. Fluorescence-based in vitro assays indicated that L. plantarum strains CRA21, CRA38 and CRA52 displayed considerable adhesion to ECM molecules, which was comparable to the probiotic Lactobacillus rhamnosus GG. Flow cytometry-based quantitative assessment of the adhesion potential suggested that L. plantarum CRA21 exhibited superior adhesion onto the ECM as compared with other lactic acid bacteria strains. Furthermore, fluorescence-based assays suggested that the highest inhibition of Staphylococcus aureus adhesion onto collagen and mucin by bacteriocin-producing L. plantarum strains was observed in the exclusion mode as compared with the competition and displacement modes. This observation was supported by the higher binding affinity (k(d)) for the ECM exhibited by the L. plantarum strains as compared with S. aureus. Interestingly, a crude plantaricin A extract from food isolates of L. plantarum displayed potent antibacterial activity on ECM-adhered S. aureus cells. It is envisaged that the L. plantarum isolates displaying bacteriocinogenic and ECM-adhering traits can perhaps be explored to develop safe antibacterial therapeutic agents. PMID:26445850
Rodrigues da Silva, Gislene; Henrique Correia Pereira, André; Guerra Pinto, Juliana; José Raniero, Leandro; Ferreira-Strixino, Juliana
The treatment of bacterial infections has been a challenge after the end of the ‘era of antibiotics’. Bacteria are capable of causing many infectious diseases; therefore, with the increasing number of bacteria becoming resistant, development of alternative therapies is needed to minimize, or even eliminate the use of antibiotics. Photodynamic therapy (PDT) is a promising alternative to fight microorganism. In view of the increasing emergence of resistant bacteria and the limitations of conventional treatment, this study evaluated the effect of photodynamic therapy with photodithazine (PDZ) in inactivating bacterial strains of E. coli and S. aureus in vitro, comparing the behavior of clinical and ATCC strains. Confocal microscopy analysis was performed to determine the internalization of the PS and spectrophotometric technique was used to determine the growth of bacteria in vitro. PDT using PDZ was able to reduce the growth of S. aureus strains using the incubation time of 24 h, whereas no satisfactory results were obtained with 15 min incubation. The E. coli strains, tested at two incubation times, did not affectively reduce bacterial growth. Therefore, it is concluded that PDT using PDZ is viable when applied to the S. aureus strains, when suitable incubation times are used.
Zhang, Wanjiang; Hao, Zhihui; Wang, Yang; Cao, Xingyuan; Logue, Catherine M; Wang, Bing; Yang, Jing; Shen, Jianzhong; Wu, Congming
The aim of this study was to determine the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolates from pet animals and veterinary staff and the characteristics of these isolates. A total of 22 MRSA isolates were isolated from nasal swabs from dogs, cats and veterinary staff in six pet hospitals in six cities, and examined for antimicrobial susceptibility, the presence of resistance genes, Panton-Valentine leukocidin gene lukF-lukS, staphylococcal chromosomal cassette (SCC) mec typing, spa tying, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Of 22 MRSA isolates, 21 were recovered from pet animals, and one was isolated from a member of sstaff. All 22 MRSA strains were resistant to penicillin, oxacillin, azithromycin, clindamycin and ceftriaxone, and harboured mecA, ermB and linA genes. The lukF-lukS gene was not detected in any of the MRSA isolates. Eighteen MRSA strains from Qingdao belonged to ST59-MRSA-IV-spa t437. Of four MRSA isolates from Beijing, one belonged to ST398-MRSA-V-spa t034, and three belonged to ST239-MRSA-III-spa t030 profiles. Two PFGE types (A and B) were identified. Two isolates originating from dogs and one isolate originating from a staff member in Beijing shared similar PFGE patterns. Our cumulative data suggested that cross-transmission of MRSA may have occurred between pet animals and veterinary staff. PMID:21382731
Antibiotic activity of the extract of Punica granatum Linn. over bovine strains of Staphylococcus aureus Atividade antimicrobiana do extrato de Punica granatum Linn. em linhagens de Staphylococcus aureus de origem bovina
Maria A. R. Silva
Full Text Available Human and veterinary medicines have not been so well succeeded in order to achieving their goals concerning the treatment of infections for long term caused by Staphylococcus aureus linked to resistance development against antibiotic agents. The antibiotic activity of the Punica granatum Linn. fresh fruit pericarp extract was evaluated by the agar diffusion method on 38 S. aureus strains, isolated from apparently healthy lactating cows in farms situated in counties of the semi-arid region of the State of Paraíba, Brazil to determine the minimum inhibitory concentration (MIC. Twenty-two of the thirty-eight strains are penicillin-resistant (PRSA. The extract of P. granatum presented potential antibiotic action over all the assayed strains, forming 10 to 36 mm diameter inhibition zones. This paper's results claim the effectiveness of the extract of P. granatum as a potential antibacterial agent on S. aureus, and display the significance of evaluating new substances with antimicrobial potential, which can contribute to alternative therapeutics for veterinary and medicine.A medicina humana e veterinária tem falhado no tratamento de infecções em longo prazo causadas por Staphylococcus aureus associadas ao desenvolvimento de resistência a agentes antimicrobianos. A atividade antimicrobiana do extrato da casca do fruto de Punica granatum Linn. foi avaliada sobre 38 linhagens de S. aureus de origem bovina para a determinação da concentração inibitória mínima (CIM. Das 38 linhagens ensaiadas, 22 são resistentes à penicilina.(PRSA. O extrato de P. granatum apresentou potencial ação antimicrobiana sobre todas as linhagens ensaiadas formando halos de inibição variando de 10 a 36 mm de diâmetro. Os resultados deste estudo confirmam a eficácia do extrato de P. granatum como potencial agente antibacteriano sobre S. aureus e demonstram a importância de se avaliar novas substâncias com potencial antimicrobiano, o que pode contribuir para a
Full Text Available The objective of this study is to determine whether various hycanthone resistant strains of schistosomes which have been independently isolated are all affected in the same gene. A strain obtained from a Brazilian patient was compared with a strain of Puerto Rican origin selected in the laboratory. If the mutation conferring resistance involved two different genes, one would expect that the progeny of a cross between the two strains would show complementation, i.e. it would be sensitive to the drug. We have performed such a cross and obtained F1 hybrid worms wich were essentially all resistant, thus suggesting that the mutation conferring resistance in the two strains involves the same gene.
Disk with High Oxacillin Content Discriminates between Methicillin-Resistant and Borderline Methicillin-Susceptible Staphylococcus aureus Strains in Disk Diffusion Assays Using a Low Salt Concentration
Petersson, Ann Cathrine; Kamme, Carl; Miörner, Håkan
A separation between mecA+ strains of Staphylococcus aureus and strains lacking mecA was achieved by the disk diffusion assay and the agar dilution method, utilizing disks containing 5 μg of oxacillin and inocula of approximately 5 × 105 CFU/spot, respectively, provided that agar with 0 to 0.5% NaCl and incubation at 30°C were employed. The 5-μg oxacillin disks clearly discriminated between borderline methicillin-susceptible and mecA+ strains. The oxacillin MICs were more affected by the inoc...
Lin, Gengrong; Appelbaum, Peter C
Among 10 hospital- and community-acquired Staphylococcus aureus strains with differing methicillin and vancomycin resistotypes, all strains were susceptible to ceftobiprole at MICs quinupristin/dalfopristin. Ceftobiprole, at 4x MIC, was bactericidal (99.9% killing) against 9 of 10 strains tested at 4x MIC after 24 h. Ceftobiprole also yielded significant activity at earlier periods, with 90% killing of all strains at 2x MIC at 6 and 12 h. Vancomycin was bactericidal against 6 of 8 strains tested at 2x MIC after 24 h. By contrast, linezolid and tigecycline were mainly bacteriostatic, and quinupristin/dalfopristin was bactericidal against 4 of 10 strains at 2x MIC after 24 h. PMID:17997257
Full Text Available Background: Methicillin-resistant Staphylococcus aureus (MRSA has emerged recently worldwide in production animals, particularly pigs and veal calves, which act as reservoirs for MRSA strains for human infection. The study determined the prevalence of MRSA and other resistant strains of S. aureus isolated from the anterior nares of pigs and human handlers on pig farms in Trinidad. Methods: Isolation of S. aureus was done by concurrently inoculating Baird-Parker agar (BPA and Chromagar MRSA (CHROM with swab samples and isolates were identified using standard methods. Suspect MRSA isolates from Chromagar and BPA were subjected to confirmatory test using Oxoid PBP2 latex agglutination test. The disc diffusion method was used to determine resistance to antimicrobial agents. Results: The frequency of isolation of MRSA was 2.1% (15 of 723 for pigs but 0.0% (0 of 72 for humans. Generally, for isolates of S. aureus from humans there was a high frequency of resistance compared with those from pigs, which had moderate resistance to the following antimicrobials: penicillin G (54.5%, 51.5%, ampicillin (59.1%, 49.5%, and streptomycin (59.1%, 37.1%, respectively. There was moderate resistance to tetracycline (36.4%, 41.2% and gentamycin (27.2%, 23.7% for human and pig S. aureus isolates, respectively, and low resistance to sulfamethoxazole-trimethoprim (4.5%, 6.2% and norfloxacin (9.1%, 12.4%, respectively. The frequency of resistance to oxacillin by the disc method was 36.4 and 34.0% from S. aureus isolates from humans and pigs, respectively. Out of a total of 78 isolates of S. aureus from both human and pig sources that were resistant to oxacillin by the disc diffusion method, only 15 (19.2% were confirmed as MRSA by the PBP'2 latex test kit. Conclusions: The detection of MRSA strains in pigs, albeit at a low frequency, coupled with a high frequency of resistance to commonly used antimicrobial agents in pig and humans could have zoonotic and therapeutic
Hall, Martica H.; Matthews, Karen A.; Kravitz, Howard M.; Gold, Ellen B.; Buysse, Daniel J.; Bromberger, Joyce T.; Owens, Jane F.; Sowers, MaryFran
Study Objectives: To examine racial differences in sleep in a large cohort of midlife women and to evaluate whether indices of socioeconomic status (SES) are associated with racial differences in sleep. Design: Cross-sectional study. Setting: Participants' homes. Participants: Caucasian (n = 171), African American (n = 138) and Chinese women (n = 59). Interventions: None. Measurements: Sleep quality was assessed with the Pittsburgh Sleep Quality Index. Polysomnographically assessed sleep duration, continuity, architecture, and NREM electroencephalograhic (EEG) power were calculated over multiple nights. Sleep disordered breathing and periodic leg movements were measured on a separate night. Linear regression analysis was used to model the independent and synergistic effects of race and SES on sleep after adjusting for other factors that impact sleep in midlife women. Indices of SES were self-reported educational attainment and financial strain. Results: Sleep was worse in African American women than Caucasian participants as measured by self-report, visual sleep stage scoring, and NREM EEG power. Slow wave sleep differences were also observed between Chinese and Caucasian participants. Racial differences persisted after adjustment for indices of SES. Although educational attainment was unrelated to sleep, financial strain was associated with decreased sleep quality and lower sleep efficiency. Financial strain-by-race interactions were not statistically significant, suggesting that financial strain has additive effects on sleep, independent of race. Conclusions: Independent relationships between race and financial strain with sleep were observed despite statistical adjustment for other factors that might account for these relationships. Results do not suggest that assessed indices of SES moderate the race-sleep relationship, perhaps due to too few women of low SES in the study. Citation: Hall MH; Matthews KA; Kravitz HM; Gold EB; Buysse DJ; Bromberger JT; Owens JF
The aim of the present thesis was to conduct an extensive characterization of S. aureus isolated from small ruminant milk and dairy products. S. aureus is considered a major public health concern because of its ability to give disease in human, after consumption of contaminated foods with enterotoxins. This pathogen can aquire resistance against several antibiotics used in human and veterinary practices. Farms and cheese-making plants can serve as a reservoir of S. aureus and are involved in ...
Balaram Das; Debasis Mandal; Sandeep Kumar Dash; Sourav Chattopadhyay; Satyajit Tripathy; Durga Pada Dolai; Sankar Kumar Dey; Somenath Roy
Due to the indiscriminate use of antibiotics, resistance to antibiotics has increased remarkably in Staphylococcus aureus. Vancomycin is the final drug to treat the S. aureus infection, but nowadays, resistance to this antibiotic is also increasing. So, the investigation of antibiotic resistance pattern is important. As there is already resistance to vancomycin, there is an urgent need to develop a new kind of antimicrobial to treat S. aureus infection. Eugenol may be the new drug of choice. ...
Full Text Available The antimicrobial activity of the synthetic peptide K9CATH was determined by the Resazurin microtitre Method (RMM against a strain of S. aureus isolated from a case of mastitis. To the antibiogram this bacteria strain showed to be resistant to Ampicillin, Erythromycin, Cefeprime, Dicloxaciline and Penicillin (10 U, while the MIC obtained for the K9CATH was 5.66 &mug/mL. Unlike the reference broth method, visual reading for MIC determination with the RMM showed to be easier, rapid, inexpensive and more sensitive for antimicrobial peptide screening, based in a color change from blue (not growth to pink (growth. This is the first time that the resazurin method is used to determine the MIC of the 38 aa´s K9CATH peptide against a mastitic isolate of S. aureus.
武超; 晏开力; 戴媛媛
目的 了解住院患者感染的金黄色葡萄球菌(methicillin sensitive staphylococcus aureus,MSSA)对常用抗生素的耐药情况,以指导临床合理使用抗生素.方法 应用VITEK32微生物自动鉴定分析系统,采用K-B法对2009-03至2011-10临床各科室分离的158株MSSA进行药物敏感性试验,并对其药敏结果 进行统计分析.结果 158株MSSA中耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus,MRSA)96株,占60.76%,对青霉素G、氨苄西林100%耐药,对万古霉素100%敏感;对甲氧西林敏感MSSA,占39.24%,对青霉素G、氨苄西林耐药率分别为69.35%和67.74%,对利奈唑胺、喹努普汀/达福普汀和万古霉素100%敏感.结论 MSSA是临床感染的主要病原菌之一,分析MSSA耐药情况,可以指导临床合理选用抗生素.%Objective To study the resistance of clinically - isolated Staphylococcus aureus to antimicrobial agents so as to facilitate the rational use of antibiotics. Methods The pathogenic bacteria were evaluated by VITEK32. Drug susceptibility test was carried out by K - B method. The results of 158 strains of Staphylococcus aureus were analysed by WHONET. Results 96 strains of MR-SA were detected from 158 strains of Staphylococcus aureus, which accounted for 60.76% . All the MRSA was resistant to penicillin and ampicillin but was sensitive to vancomycin. The resistance rate of MSSA to penicillin and ampicillin was 69.35% and 67.74% , respectively, and all the MSSA was sensitive to linezolid, quinupristin/dalfopristin and vancomycin. Conclusions Staphylococcus aureus is one of the main pathogens of clinical infection. Analysis of drug resistance of Staphylococcus aureus can guide the clinical use of antibiotics.
Mellmann, Alexander; Weniger, Thomas; Berssenbrügge, Christoph; Keckevoet, Ursula; Friedrich, Alexander W; Harmsen, Dag; Grundmann, Hajo
We evaluated the BURP (based upon repeat patterns) algorithm, which relies on sequencing of the Staphylococcus aureus protein A gene (spa), for its ability to infer clonal relatedness within a population of 110 wild-type strains. BURP clustering of the resulting 66 spa types was highly concordant with multilocus sequence typing (96.5% concordance) and pulsed-field gel electrophoresis (94.9%). PMID:18524961
Mellmann, Alexander; Weniger, Thomas; Berssenbrügge, Christoph; Keckevoet, Ursula; Friedrich, Alexander W.; Harmsen, Dag; Grundmann, Hajo
We evaluated the BURP (based upon repeat patterns) algorithm, which relies on sequencing of the Staphylococcus aureus protein A gene (spa), for its ability to infer clonal relatedness within a population of 110 wild-type strains. BURP clustering of the resulting 66 spa types was highly concordant with multilocus sequence typing (96.5% concordance) and pulsed-field gel electrophoresis (94.9%).
Assadian, Ojan; Wehse, Katrin; Hübner, Nils-Olaf; Koburger, Torsten; Bagel, Simone; Jethon, Frank; Kramer, Axel
Background: An in-vitro study was conducted investigating the antimicrobial efficacy of polihexanide and triclosan against clinical isolates and reference laboratory strains of Staphylococcus aureus and E scherich ia coli. Methods: The minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC) were determined following DIN 58940-81 using a micro-dilution assay and a quantitative suspension test following EN 1040. Polihexanide was tested in polyethylene glycol 4000...
Genestier, Anne-Laure; Michallet, Marie-Cécile; Prévost, Gilles; Bellot, Gregory; Chalabreysse, Lara; Peyrol, Simone; Thivolet, Françoise; Etienne, Jerome; Lina, Gérard; Vallette, François M.; Vandenesch, François; Genestier, Laurent
Panton-Valentine leukocidin (PVL) is a pore-forming toxin secreted by Staphylococcus aureus that has recently been associated with necrotizing pneumonia. In the present study, we report that in vitro, PVL induces polymorphonuclear cell death by necrosis or by apoptosis, depending on the PVL concentration. PVL-induced apoptosis was associated with a rapid disruption of mitochondrial homeostasis and activation of caspase-9 and caspase-3, suggesting that PVL-induced apoptosis is preferentially m...
Guo, Jun; Han, Na; Zhang, Yuanyuan; Wang, Haiyin; Zhang, Xuelin; Su, Longxiang; Liu, Chao; Li, Jia; Chen, Chen; Liu, Changting
The extreme environment of space could affect microbial behavior and may increase the risk of infectious disease during spaceflight. However, the molecular genetic changes of methicillin-resistant Staphylococcus aureus (MRSA) in response to the spaceflight environment have not been fully clarified. In the present study, we determined the draft genome sequences for an ancestral S. aureus strain (LCT-SAO) isolated from a clinical sample and three derivative strains, LCT-SAS, LCT-SAM and LCT-SAG, cultured in parallel during the spaceflight Shenzhou-X, under simulated microgravity and on the ground, respectively. To evaluate the impact of short-term spaceflight on the MRSA strains, comparative genomic analysis was implemented. Genome-based mapping of toxin genes and antibiotic resistance genes confirmed that these strains have the conventional pathogenicity and resistance to drugs, as none of the strains showed significant changes in these regions after culturing in the three different environments; this result suggests that spaceflight may not change bacterial virulence or drug resistance. Thirty-nine strain-specific sequence variants (SVs) were identified throughout the genomes, and the three derivatives exhibited almost the same mutation rates. Fifty-nine percent of SVs were located in the intergenic regions of the genomes, indicating that S. aureus may have an extremely robust repair mechanism responsible for recognizing and repairing DNA replication mismatches. It is noteworthy that strain LCT-SAS, cultured in space, presented the most unique SVs (n=9) and shared the fewest SVs with LCT-SAM (n=5) and LCT-SAG (n=4). Furthermore, we identified 10 potential deletion regions and 2 potential insertion regions, with LCT-SAS appearing more fragile than other strains by this measure. These results suggest that the environment of space is inherently complicated, with multiple variables, and cannot be simulated in a simple manner. Our results represent the first analysis of
Bui, Long M G; Kidd, Stephen P
A key to persistent and recurrent Staphylococcus aureus infections is its ability to adapt to diverse and toxic conditions. This ability includes a switch into a biofilm or to the quasi-dormant Small Colony Variant (SCV). The development and molecular attributes of SCVs have been difficult to study due to their rapid reversion to their parental cell-type. We recently described the unique induction of a matrix-embedded and stable SCV cell-type in a clinical S. aureus strain (WCH-SK2) by growing the cells with limiting conditions for a prolonged timeframe. Here we further study their characteristics. They possessed an increased viability in the presence of antibiotics compared to their non-SCV form. Their stability implied that there had been genetic changes; we therefore determined both the genome sequence of WCH-SK2 and its stable SCV form at a single base resolution, employing Single Molecular Real-Time (SMRT) sequencing that enabled the methylome to also be determined. The genetic features of WCH-SK2 have been identified; the SCCmec type, the pathogenicity and genetic islands and virulence factors. The genetic changes that had occurred in the stable SCV form were identified; most notably being in MgrA, a global regulator, and RsbU, a phosphoserine phosphatase within the regulatory pathway of the sigma factor SigB. There was a shift in the methylomes of the non-SCV and stable SCV forms. We have also shown a similar induction of this cell-type in other S. aureus strains and performed a genetic comparison to these and other S. aureus genomes. We additionally map RNAseq data to the WCH-SK2 genome in a transcriptomic analysis of the parental, SCV and stable SCV cells. The results from this study represent the unique identification of a suite of epigenetic, genetic and transcriptional factors that are implicated in the switch in S. aureus to its persistent SCV form. PMID:26458527
Avaliação da tolerância à vancomicina em 395 cepas hospitalares de Staphylococcus aureus resistentes à oxacilina Evaluation of the tolerance to vancomycin in 395 oxacillin-resistant Staphylococcus aureus strains isolated from Brazilian hospitals
Geraldo A. Oliveira
Full Text Available O objetivo deste estudo foi avaliar a presença de tolerância à vancomicina em cepas de Staphylococcus aureus resistentes à oxacilina (Orsa isoladas de quatro hospitais da cidade de São Paulo. Foram estudadas 395 cepas Orsa isoladas de pacientes hospitalizados entre outubro de 1998 e maio de 2000. A determinação da concentração inibitória mínima (CIM e da concentração bactericida mínima (CBM para vancomicina foi realizada conforme padronizado pelo National Committee for Clinical Laboratory Standards (NCCLS. A tolerância à vancomicina foi definida como a razão CBM/CIM > ou = 32. Do total de cepas estudadas, 10,4% apresentaram CIM de 0,5µg/ml para vancomicina; 41,3%, CIM de 1µg/ml; 42,2%, CIM de 2µg/ml; e 6,1%, CIM de 4µg/ml. Em média, 49,1% dos Orsa apresentaram tolerância à vancomicina. Em conclusão, a tolerância à vancomicina entre as cepas Orsa foi considerada elevada. Conseqüentemente, aumentam as chances de falhas no tratamento com vancomicina, além de aumentar o risco da emergência de Staphylococcus aureus vancomicina-intermediário.The objective of this study was to evaluate the presence of tolerance to vancomycin in oxacillin-resistant Staphylococcus aureus (Orsa strains isolated from four hospitals in the city of São Paulo. From October/1998 to May/2000 we analysed 395 Orsa strains isolated from hospitalized patients. MIC and MBC to vancomycin were determined as standardised by National Committee for Clinical Laboratory Standards (NCCLS. Tolerance was defined as the ratio MBC/MIC > or = 32. The results showed that 10.4% of the Orsa strains presented a MIC of 0.5µg/mL for vancomycin, 41.3% presented a MIC of 1µg/mL, 42.2% a MIC of 2µg/mL and 6.1% a MIC of 4µg/mL. On average, 49,1% of the Orsa presented tolerance to vancomycin. We conclude that the tolerance to vancomycin amongst the Orsa strains was considered high. These high levels of tolerance augment the chances of failure in the treatment with
Ulbrich, Norbert Manfred
A new method was developed that makes it possible to use an extended set of independent calibration variables for an iterative analysis of wind tunnel strain gage balance calibration data. The new method permits the application of the iterative analysis method whenever the total number of balance loads and other independent calibration variables is greater than the total number of measured strain gage outputs. Iteration equations used by the iterative analysis method have the limitation that the number of independent and dependent variables must match. The new method circumvents this limitation. It simply adds a missing dependent variable to the original data set by using an additional independent variable also as an additional dependent variable. Then, the desired solution of the regression analysis problem can be obtained that fits each gage output as a function of both the original and additional independent calibration variables. The final regression coefficients can be converted to data reduction matrix coefficients because the missing dependent variables were added to the data set without changing the regression analysis result for each gage output. Therefore, the new method still supports the application of the two load iteration equation choices that the iterative method traditionally uses for the prediction of balance loads during a wind tunnel test. An example is discussed in the paper that illustrates the application of the new method to a realistic simulation of temperature dependent calibration data set of a six component balance.
Full Text Available Abstract Background Staphylococcus aureus is a major human pathogen responsible for a variety of nosocomial and community-acquired infections. Recent reports show that the prevalence of Methicillin-Resistant S. aureus (MRSA infections in cystic fibrosis (CF patients is increasing. In 2006 in Marseille, France, we have detected an atypical MRSA strain with a specific antibiotic susceptibility profile and a unique growth phenotype. Because of the clinical importance of the spread of such strain among CF patients we decided to sequence the genome of one representative isolate (strain CF-Marseille to compare this to the published genome sequences. We also conducted a retrospective epidemiological analysis on all S. aureus isolated from 2002 to 2007 in CF patients from our institution. Results CF-Marseille is multidrug resistant, has a hetero-Glycopeptide-Intermediate resistance S. aureus phenotype, grows on Cepacia agar with intense orange pigmentation and has a thickened cell wall. Phylogenetic analyses using Complete Genome Hybridization and Multi Locus VNTR Assay showed that CF-Marseille was closely related to strain Mu50, representing vancomycin-resistant S. aureus. Analysis of CF-Marseille shows a similar core genome to that of previously sequenced MRSA strains but with a different genomic organization due to the presence of specific mobile genetic elements i.e. a new SCCmec type IV mosaic cassette that has integrated the pUB110 plasmid, and a new phage closely related to phiETA3. Moreover this phage could be seen by electron microscopy when mobilized with several antibiotics commonly used in CF patients including, tobramycin, ciprofloxacin, cotrimoxazole, or imipenem. Phylogenetic analysis of phenotypically similar h-GISA in our study also suggests that CF patients are colonized by polyclonal populations of MRSA that represents an incredible reservoir for lateral gene transfer. Conclusion In conclusion, we demonstrated the emergence and
Gongora, Carmen Espinosa; Moodley, Arshnee; Lipinska, Urszula;
INTRODUCTION: Staphylococcus aureus sequence type ST398 has recently gained attention due to the spread of methicillin-resistant strains among people exposed to livestock. The aim of this study was to explore temporal changes in the population structure of S. aureus in pigs over the last 40 years...... historical isolates from 1973-1974 (n = 19) and from 1991-2003 (n = 13), and 59 contemporary isolates from 2004-2009. The latter isolates represented the most common MLST types (ST1, ST9, ST97 and ST433) and spa types isolated from pigs in Europe. RESULTS AND DISCUSSION: S. aureus sequence type ST398...... isolates are occasionally reported in pigs today (ST8, ST30, ST97, ST387, ST1092, ST2468) or have never been described in this animal host (ST12, ST133, ST1343). These results indicate that the population structure of porcine S. aureus has changed over the last 40 years and confirm the current theory...
Jacob, J; Meers, P D
Selected strains of methicillin- and aminoglycoside-resistant Staphylococcus aureus (MARSA) were subjected to a preliminary examination. They were representative of a larger group collected in a routine clinical microbiology laboratory over a period of 2 years. MARSA was endemic in the associated hospital. The characteristics investigated were antimicrobial resistance, the production of beta-lactamase, free and bound coagulase, protein A, DNA-ase, urease, lipase and pigment. The MARSA strains were generally indistinguishable, other than in their antimicrobial resistances. The resistance to methicillin was completely homogeneous. Except with imipenem, growth extended to the edge of discs containing methicillin and the other beta-lactam antibiotics tested when the strains were cultured at 37 degrees C on media without added salt. Homogeneous resistance may confer an epidemiological advantage on strains of this phenotype. PMID:1353087
Full Text Available Background: An in-vitro study was conducted investigating the antimicrobial efficacy of polihexanide and triclosan against clinical isolates and reference laboratory strains of Staphylococcus aureus and Escherichia coli. Methods: The minimal inhibitory concentration (MIC and the minimal microbicidal concentration (MMC were determined following DIN 58940-81 using a micro-dilution assay and a quantitative suspension test following EN 1040. Polihexanide was tested in polyethylene glycol 4000, triclosan in aqueous solutions. Results: Against all tested strains the MIC of polihexanide ranged between 1–2 µg/mL. For triclosan the MICs varied depending on strains ranging between 0.5 µg/mL for the reference strains and 64 µg/mL for two clinical isolates. A logRF >5 without and logRF >3 with 0.2% albumin burden was achieved at 0.6 µg/mL triclosan. One exception was S. aureus strain H-5-24, where a triclosan concentration of 0.6 µg/mL required 1 minute without and 10 minutes with albumin burden to achieve the same logRFs. Polihexanide achieved a logRF >5 without and logRF >3 with albumin burden at a concentration of 0.6 µg/mL within 30 sec. The exception was the North-German epidemic MRSA strain, were an application time of 5 minutes was required. Conclusion: The clinical isolates of E. coli generally showed higher MICs against triclosan, both in the micro-dilution assay as well in the quantitative suspension test than comparable reference laboratory strains. For polihexanide and triclosan strain dependant susceptibility was shown. However, both antimicrobial compounds are effective when used in concentrations common in practice.
Bardiau, Marjorie; Caplin, Jonathan; Detilleux, Johann; Graber, Hans; Moroni, Paolo; Taminiau, Bernard; Mainil, Jacques G
Staphylococcus (S.) aureus is recognised worldwide as an important pathogen causing contagious acute and chronic bovine mastitis. Chronic mastitis account for a significant part of all bovine cases and represent an important economic problem for dairy producers. Several properties (biofilm formation, intracellular survival, capsular expression and group agr) are thought to be associated with this chronic status. In a previous study, we found the existence of two groups of strains based on the association of these features. The aim of the present work was to confirm on a large international and non-related collection of strains the existence of these clusters and to associate them with case history records. In addition, the genomes of eight strains were sequenced to study the genomic differences between strains of each cluster. The results confirmed the existence of both groups based on capsular typing, intracellular survival and agr-typing: strains cap8-positive, belonging to agr group II, showing a low invasion rate and strains cap5-positive, belonging to agr group I, showing a high invasion rate. None of the two clusters were associated with the chronic status of the cow. When comparing the genomes of strains belonging to both clusters, the genes specific to the group "cap5-agrI" would suggest that these strains are better adapted to live in hostile environment. The existence of these two groups is highly important as they may represent two clusters that are adapted differently to the host and/or the surrounding environment. PMID:26931384
Movement of the tectonic plates leads to strain build-up in the Earth, which can be released during earthquakes when one side of a seismic fault suddenly slips with respect to the other one. The amount of seismic strain release (or 'strain drop') is thus a direct measurement of a basic earthquake property, i.e. the ratio of seismic slip over the dimension of the ruptured fault. SCARDEC, a recently developed method, gives access to this information through the systematic determination of earthquakes source time functions (STFs). STFs describe the integrated spatio-temporal history of the earthquake process, and their maximum value can be related to the amount of stress or strain released during the earthquake. Here I analyse all earthquakes with magnitudes greater than 6 occurring in the last 20 years, and thus provide a catalogue of 1700 STFs which sample all the possible seismic depths. Analysis of this new database reveals that the strain drop remains on average the same for all earthquakes, independent of magnitude and depth. In other words, it is shown that, independent of the earthquake depth, magnitude 6 and larger earthquakes keep on average a similar ratio between seismic slip and dimension of the main slip patch. This invariance implies that deep earthquakes are even more similar than previously thought to their shallow counterparts, a puzzling finding as shallow and deep earthquakes should originate from different physical mechanisms. Concretely, the ratio between slip and patch dimension is on the order of 10-5-10-4, with extreme values only 8 times lower or larger at the 95% confidence interval. Besides the implications for mechanisms of deep earthquake generation, this limited variability has practical implications for realistic earthquake scenarios.
Rasoul Y. Mashouf
Full Text Available Objectives: The aims of our study were to evaluate the prevalence of Staphylococcus aureus (S. aureus strains in food samples of animal origin, examine their antibacterial susceptibility pattern, and to detect staphylococcal enterotoxin (SEs genes and the mecA gene in isolated S. aureus strains using the polymerase chain reaction (PCR. Methods: A total of 1050 food samples including 671 raw milk and dairy products and 379 raw meats were collected between September 2013 and June 2014 in Hamadan, Iran. Food samples were analyzed for S. aureus identification. The antibiotic susceptibility pattern of all isolates was determined using the disk agar diffusion method followed by detecting mecA resistance gene using PCR. In addition, harboring of SE genes were determined using a multiplex PCR assay targeting nine genes. Results: A total of 98 (9.3% S. aureus strains were isolated from 1050 food samples. Of the 98 isolates examined, the most frequent resistance was observed to erythromycin (30.6%, followed by tetracycline (29.6%, gentamicin (27.6%, clindamycin (26.5%, ciprofloxacin and rifampin (24.5%, trimethoprim-sulfamethoxazole (14.3%, and cefoxitin (5.1%. All cefoxitin resistant isolates were positive for mecA. The prevalence of SEs was 77.6% (n=76. Among the genes that code classic enterotoxins, sea was the most frequent and was carried by 25.5% of isolates, followed by see in 18.4%, sed in 11.2%, sec in 5.1%, and seb in 4.1% of isolates. Among the detected enterotoxins, seg was the predominantly identified enterotoxin gene in isolates with prevalence of 35.7%. The seh gene with prevalence of 1% and sei gene with 3.1% were other detected enterotoxins with low frequencies. Conclusion: The high prevalence of SE genes detected indicates a potential risk for causing animal-originated food poisoning. The increasing prevalence of community-acquired MRSA and its emerging antibiotic resistance in foods is a serious problem for public health.
Full Text Available An isolate of the methicillin-resistant Staphylococcus aureus (MRSA clone USA300 with reduced susceptibility to vancomycin (SG-R (i.e, vancomycin-intermediate S. aureus, VISA and its susceptible "parental" strain (SG-S were recovered from a patient at the end and at the beginning of an unsuccessful vancomycin therapy. The VISA phenotype was unstable in vitro generating a susceptible revertant strain (SG-rev. The availability of these 3 isogenic strains allowed us to explore genetic correlates of antibiotic resistance as it emerged in vivo. Compared to the susceptible isolate, both the VISA and revertant strains carried the same point mutations in yycH, vraG, yvqF and lspA genes and a substantial deletion within an intergenic region. The revertant strain carried a single additional frameshift mutation in vraS which is part of two component regulatory system VraSR. VISA isolate SG-R showed complex alterations in phenotype: decreased susceptibility to other antibiotics, slow autolysis, abnormal cell division and increased thickness of cell wall. There was also altered expression of 239 genes including down-regulation of major virulence determinants. All phenotypic properties and gene expression profile returned to parental levels in the revertant strain. Introduction of wild type yvqF on a multicopy plasmid into the VISA strain caused loss of resistance along with loss of all the associated phenotypic changes. Introduction of the wild type vraSR into the revertant strain caused recovery of VISA type resistance. The yvqF/vraSR operon seems to function as an on/off switch: mutation in yvqF in strain SG-R turns on the vraSR system, which leads to increase in vancomycin resistance and down-regulation of virulence determinants. Mutation in vraS in the revertant strain turns off this regulatory system accompanied by loss of resistance and normal expression of virulence genes. Down-regulation of virulence genes may provide VISA strains with a "stealth
Kang, Jun; Sahin, Hasan; Ozaydin, H. Duygu; Senger, R. Tugrul; Peeters, François M.
The electronic properties, carrier mobility, and strain response of TiS3 nanoribbons (TiS3 NRs) are investigated by first-principles calculations. We found that the electronic properties of TiS3 NRs strongly depend on the edge type (a or b). All a-TiS3 NRs are metallic with a magnetic ground state, while b-TiS3 NRs are direct band gap semiconductors. Interestingly, the size of the band gap and the band edge position are almost independent of the ribbon width. This feature promises a constant band gap in a b-TiS3 NR with rough edges, where the ribbon width differs in different regions. The maximum carrier mobility of b-TiS3 NRs is calculated by using the deformation potential theory combined with the effective mass approximation and is found to be of the order 103cm2V-1s-1 . The hole mobility of the b-TiS3 NRs is one order of magnitude lower, but it is enhanced compared to the monolayer case due to the reduction in hole effective mass. The band gap and the band edge position of b-TiS3 NRs are quite sensitive to applied strain. In addition we investigate the termination of ribbon edges by hydrogen atoms. Upon edge passivation, the metallic and magnetic features of a-TiS3 NRs remain unchanged, while the band gap of b-TiS3 NRs is increased significantly. The robust metallic and ferromagnetic nature of a-TiS3 NRs is an essential feature for spintronic device applications. The direct, width-independent, and strain-tunable band gap, as well as the high carrier mobility, of b-TiS3 NRs is of potential importance in many fields of nanoelectronics, such as field-effect devices, optoelectronic applications, and strain sensors.
Full Text Available Background: Microorganisms develop biofilm on various medical devices. The process is particularly relevant in public health since biofilm associated organisms are much more resistant to antibiotics and have a potential to cause infections in patients with indwelling medical devices. Materials and Methods: To determine the efficiency of an antibiotic against the biofilm it is inappropriate to use traditional technique of determining Minimum Inhibitory Concentration (MIC on the free floating laboratory phenotype. Thus we have induced formation of biofilm in two strains (Pseudomonas aeruginosa and Staphylococcus aureus, which showed heavy growth of biofilm in screening by Tube method in a flow cell system and determined their antibiotic susceptibility against ciprofloxacin by agar dilution method in the range (0.25 mg/ml to 8 mg/ml. The MIC value of ciprofloxacin for the biofilm produced organism was compared with its free form and a standard strain as control on the same plates. Observations: Both the biofilm produced strains showed a higher resistance (MIC > 8 mg/ml than its free form, which were 2 μg/ml for Pseudomonas aeruginosa and 4 mg/ml for Staphylococcus aureus. Thus biofilm can pose a threat in the patient treatment.
Activities of the Combination of Quinupristin-Dalfopristin with Rifampin In Vitro and in Experimental Endocarditis Due to Staphylococcus aureus Strains with Various Phenotypes of Resistance to Macrolide-Lincosamide-Streptogramin Antibiotics
Zarrouk, Virginie; Bozdogan, Bülent; Leclercq, Roland; Garry, Louis; Feger, Celine; Carbon, Claude; Fantin, Bruno
We evaluated the activities of quinupristin-dalfopristin (Q-D), alone or in combination with rifampin, against three strains of Staphylococcus aureus susceptible to rifampin (MIC, 0.06 μg/ml) and to Q-D (MICs, 0.5 to 1 μg/ml) but displaying various phenotypes of resistance to macrolide-lincosamide-streptogramin antibiotics: S. aureus HM1054 was susceptible to quinupristin and dalfopristin (MICs of 8 and 4 μg/ml, respectively); for S. aureus RP13, the MIC of dalfopristin was high (MICs of quin...
Intra- and extracellular activities of dicloxacillin and linezolid against a clinical Staphylococcus aureus strain with a small-colony-variant phenotype in an in vitro model of THP-1 macrophages and an in vivo mouse peritonitis model
Sandberg, A.; LEMAIRE, S.; Van Bambeke, F.; Tulkens, P M; Hughes, D.; von Eiff, C.; Frimodt-Moller, N.
The small-colony-variant (SCV) phenotype of Staphylococcus aureus has been associated with difficult-to-treat infections, reduced antimicrobial susceptibility, and intracellular persistence. This study represents a detailed intra- and extracellular investigation of a clinical wild-type (WT) S. aureus strain and its counterpart with an SCV phenotype both in vitro and in vivo, using the THP-1 cell line model and the mouse peritonitis model, respectively. Bacteria of both phenotypes infected the...
Liu, Xiaoli; Liang, Jiansheng; Jiang, Yuanshan; Wang, Bin; Yuan, Hong; Zhang, Lihua; Zhou, Yanfei; Xu, Huiqiong; Zhou, Wang
This study aims to investigate the antimicrobial susceptibility, molecular characteristics and virulence genes of community-acquired methicillin-resistant ITALIC! Staphylococcus aureus(CA-MRSA) isolates with skin and soft tissue infections (SSTIs). Outpatients with SSTIs visiting five medical and health institutions were enrolled from 2011 to 2013. Available ITALIC! S. aureus isolates were characterized by antimicrobial susceptibility testing, and detection of PVL genes. For CA-MRSA isolates, we performed typing of staphylococcal cassette chromosome ITALIC! mec(SCC ITALIC! mec), multi locus sequence typing (MLST) and carriage of 27 virulence genes. A total of 203 ITALIC! S. aureusstrains were isolated from 1400 outpatients with SSTIs, and 21 (10.3%) were CA-MRSA isolates. The positive rate of PVL genes among ITALIC! S. aureus, CA-MRSA and methicillin-susceptible ITALIC! S. aureus(MSSA) isolates were 39.4%, 71.4% and 35.7%, respectively. CA-MRSA strains had greater sensitivity to non-β-lactam antimicrobial agents. All CA-MRSA isolates belonged to SCC ITALIC! mecIV and V, accounting for 47.6% and 52.4%, respectively. ST59 was the most common lineage accounting for 76.2%; ST59-SCC ITALIC! mecIVa-PVL-positive clone was found to be the predominant clone, accounting for 38.1%. All CA-MRSA isolates were found to be positive for one or more virulence genes, 28.6% of isolates carried PVL, ITALIC! seb, ITALIC! sek, ITALIC! seq, ITALIC! hla, ITALIC! hlb, ITALIC! hldand ITALIC! hlg-2. CA-MRSA infections were relatively uncommon in outpatients with SSTIs, but they carried many virulence genes, ST59-SCC ITALIC! mecIV a-PVL-positive clone was the predominant clone in Wuhan, China. PMID:27060098
Yaser; Hamadeh; Tarazi; Ahmed; Mahmoud; Almajali; Mustafa; Mohammad; Kheer; Ababneh; Humam; Shawket; Ahmed; Adnan; Saleem; Jaran
Objective: To determine the prevalence, genetic relatedness, and pattern of antimicrobial susceptibility in methicillin-resistant Staphylococcus aureus(S. aureus)(MRSA) isolated from household dogs, farm dogs, and stray dogs, compared to isolates from their associated personnel.Methods: MRSA was isolated from 250 nasal swabs(150 swabs from dogs and 100 swabs from humans). PCR assays were used to detect the presence of both the nuc and mec A genes,which con firmed the identity of S. aureus isolates and the presence of methicillin resistance,respectively. Disk diffusion was used to determine the antibiotic susceptibility against 15 antimicrobial agents along with an E-test that determined the minimum inhibitory concentration for oxacillin. Pulsed field gel electrophoresis was conducted to determine the genetic relatedness of MRSA isolates from dogs to those from associated and unassociated personnel.Results: The prevalence of S. aureus in dogs and humans was 12.7% and 10.0%respectively, while the prevalence of MRSA isolates in dogs and humans was 5.3% and5.0%, respectively. The prevalence of MRSA isolates in household dogs, farm dogs, and stray dogs was 7.8%, 4.7%, and 0.0%, respectively. MRSA isolates demonstrated a significantly higher rate of multi-resistance against three or more antimicrobial agents than methicillin-susceptible S. aureus(MSSA). Trimethoprim-sulphamethoxazole and chloramphenicol were the most effective antibiotics against all MRSA isolates. Pulsed field gel electrophoresis revealed a strong association between dog MRSA isolates and MRSA isolates from strongly associated personnel.Conclusions: MRSA is prevalent in house dogs, as well as in dog rearing centers and among their strongly associated personnel. A strong association was found between the MRSA isolates from dogs and those from humans who are in close contact. In addition,MRSA isolates showed a high rate of multi-resistance compared to MSSA isolates.
Yaser Hamadeh Tarazi; Ahmed Mahmoud Almajali; Mustafa Mohammad Kheer Ababneh; Humam Shawket Ahmed; Adnan Saleem Jaran
Objective:To determine the prevalence, genetic relatedness, and pattern of antimicrobial susceptibility in methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA) isolated from household dogs, farm dogs, and stray dogs, compared to isolates from their associated personnel. Methods: MRSA was isolated from 250 nasal swabs (150 swabs from dogs and 100 swabs from humans). PCR assays were used to detect the presence of both the nuc and mecA genes, which confirmed the identity of S. aureus isolates and the presence of methicillin resistance, respectively. Disk diffusion was used to determine the antibiotic susceptibility against 15 antimicrobial agents along with an E-test that determined the minimum inhibitory concentration for oxacillin. Pulsed field gel electrophoresis was conducted to determine the genetic relatedness of MRSA isolates from dogs to those from associated and unassociated personnel. Results:The prevalence of S. aureus in dogs and humans was 12.7%and 10.0%respectively, while the prevalence of MRSA isolates in dogs and humans was 5.3%and 5.0%, respectively. The prevalence of MRSA isolates in household dogs, farm dogs, and stray dogs was 7.8%, 4.7%, and 0.0%, respectively. MRSA isolates demonstrated a significantly higher rate of multi-resistance against three or more antimicrobial agents than methicillin-susceptible S. aureus (MSSA). Trimethoprim-sulphamethoxazole and chloramphenicol were the most effective antibiotics against all MRSA isolates. Pulsed field gel electrophoresis revealed a strong association between dog MRSA isolates and MRSA isolates from strongly associated personnel. Conclusions:MRSA is prevalent in house dogs, as well as in dog rearing centers and among their strongly associated personnel. A strong association was found between the MRSA isolates from dogs and those from humans who are in close contact. In addition, MRSA isolates showed a high rate of multi-resistance compared to MSSA isolates.
Davis, Meghan F; Misic, Ana M; Morris, Daniel O; Moss, John T; Tolomeo, Pam; Beiting, Daniel P; Nachamkin, Irving; Lautenbach, Ebbing; Rankin, Shelley C
The strain dynamics of methicillin-resistant Staphylococcus aureus (MRSA) isolates from people and the household dog were investigated. The isolates were identified in the context of a randomized controlled trial that tested household-wide decolonization of people. Genotypic comparison of MRSA isolates obtained from two household members, the dog, and home surfaces over a three-month period failed to implicate the pet or the home environment in recurrent colonization of the household members. However, it did implicate the pet's bed in exposure of the dog prior to the dog's infection. Whole genome sequencing was performed to differentiate the isolates. This report also describes introduction of diverse strains of MRSA into the household within six weeks of cessation of harmonized decolonization treatment of people and treatment for infection in the dog. These findings suggest that community sources outside the home may be important for recurrent MRSA colonization or infection. PMID:26411322
Cellular pharmacokinetics and intracellular activity of the novel peptide deformylase inhibitor GSK1322322 against Staphylococcus aureus laboratory and clinical strains with various resistance phenotypes: studies with human THP-1 monocytes and J774 murine macrophages.
Peyrusson, Frédéric; Butler, Deborah; Tulkens, Paul M; Van Bambeke, Françoise
GSK1322322 is a peptide deformylase inhibitor active against Staphylococcus aureus strains resistant to currently marketed antibiotics. Our aim was to assess the activity of GSK1322322 against intracellular S. aureus using an in vitro pharmacodynamic model and, in parallel, to examine its cellular pharmacokinetics and intracellular disposition. For intracellular activity analysis, we used an established model of human THP-1 monocytes and tested one fully susceptible S. aureus strain (ATCC 25923) and 8 clinical strains with resistance to oxacillin, vancomycin, daptomycin, macrolides, clindamycin, linezolid, or moxifloxacin. Uptake, accumulation, release, and subcellular distribution (cell fractionation) of [(14)C]GSK1322322 were examined in uninfected murine J774 macrophages and uninfected and infected THP-1 monocytes. GSK1322322 demonstrated a uniform activity against the intracellular forms of all S. aureus strains tested, disregarding their resistance phenotypes, with a maximal relative efficacy (E max) of a 0.5 to 1 log10 CFU decrease compared to the original inoculum within 24 h and a static concentration (C s) close to its MIC in broth. Influx and efflux were very fast (gemfibrozil and verapamil. GSK1322322 was recovered in the cell-soluble fraction and was dissociated from the main subcellular organelles and from bacteria (in infected cells). The results of this study show that GSK1322322, as a typical novel deformylase inhibitor, may act against intracellular forms of S. aureus. They also suggest that GSK1322322 has the ability to freely diffuse into and out of eukaryotic cells as well as within subcellular compartments. PMID:26169402
Lívia Viganor da Silva
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA and coagulase-negative Staphylococcus spp (CNS are the most common pathogens that cause serious long term infections in patients. Despite the existence of new antimicrobial agents, such as linezolid, vancomycin (VAN remains the standard therapy for the treatment of infections caused by these multidrug-resistant strains. However, the use of VAN has been associated with a high frequency of therapeutic failures in some clinical scenarios, mainly with decreasing concentration of VAN. This work aims to evaluate the synergic potential of VAN plus sulfamethoxazole/trimethoprim (SXT, VAN plus rifampin (RIF and VAN plus imipenem (IPM in sub-minimum inhibitory concentrations against 22 clinical strains of MRSA and CNS. The checkerboard method showed synergism of VAN/RIF and VAN/SXT against two and three of the 22 strains, respectively. The combination of VAN with IPM showed synergistic effects against 21 out of 22 strains by the E-test method. Four strains were analyzed by the time-kill curve method and synergistic activity was observed with VAN/SXT, VAN/RIF and especially VAN/IPM in sub-inhibitory concentrations. It would be interesting to determine if synergy occurs in vivo. Evidence of in vivo synergy could lead to a reduction of the standard VAN dosage or treatment time.
Robust indices of regional and global cardiac function are a key factor in detection and treatment of heart disease as well as understanding of the fundamental mechanisms of a healthy heart. Myocardial elastography provides a noninvasive method for imaging and measuring displacement and strain of the myocardium for the early detection of cardiovascular disease. However, two-dimensional in-plane axial and lateral strains measured depend on the sonographic view used. This becomes especially critical in a clinical setting and may induce large variations in the measured strains, potentially leading to false diagnoses. A novel method in myocardial elastography is proposed for eliminating this view dependence by deriving the polar, principal and classified principal strains. The performance of the proposed methodology is assessed by employing 3D finite-element left-ventricular models of a control and an ischemic canine heart. Although polar strains are angle-independent, they are sensitive to the selected reference coordinate system, which requires the definition of a centroid of the left ventricle (LV). In contrast, principal strains derived through eigenvalue decomposition exhibit the inherent characteristic of coordinate system independence, offering view (i.e., angle and centroid)-independent strain measurements. Classified principal strains are obtained by assigning the principal components in the physical ventricular coordinate system. An extensive strain analysis illustrates the improvement in interpretation and visualization of the full-field myocardial deformation by using the classified principal strains, clearly depicting the ischemic and non-ischemic regions. Strain maps, independent of sonographic views and imaging planes, that can be used to accurately detect regional contractile dysfunction are demonstrated
孔晋亮; 张东伟; 陈一强; 闫萍; 蔡双启; 简丽娟
目的 比较临床分离同源性金黄色葡萄球菌(SAU)的黏附及生物被膜(BF)形成能力差异.方法 刚果红平板法定性能形成BF的菌株；建立SAU的BF体外静置模型,分别于建模第1、3、7天,采用结晶紫染色方法,比较临床分离同源性SAU的黏附及BF形成能力差异.结果 临床分离10株同源性SAU中,刚果红平板法定性可全部形成BF；SAU 17546的黏附及形成早期BF能力最强(P＜0.001),而SAU 17422最弱(P＜0.001)；形成成熟BF能力,仍以SAU 17546最强(P＜0.001),但SAU 17642与17546比较,两者极近似(P =0.495)；SAU 17422形成BF能力最弱,但是与17431、18541-2、18558、18565、18719等菌株差异无统计学意义.结论 刚果红平板法可定性SAU形成BF菌株,同源性SAU黏附及形成BF的能力存在差异.%OBJECTIVE To compare the adhesion and the abilities of biofilm formation of the homologous clinical isolates of Staphylococcus aureus. METHODS Congo red plate method was used to detect strains The in vitro biofilm model of S. aureus was established, and the crystal violet staining biofilm semi-quantitative method was employed to compare the adhesion and biofilm formation abilities of the homologous S. aureus. RESULTS Totally 10 strains of homologous S. aureus were biofilm formation-positive, which were isolated from the clinic. The ability of adhesion and early biofilm formation of S. aureus 17546 was the strongest (P<0. 001), but S. aureus 17422's was the weakest (P<0. 001). As for the formation ability of the mature biofilm, S. aureus 17546 was the most powerful (P<0. 001), S. aureus 17642 was extremely similar to strain 17546(P=0. 495). the biofilm formation ability of S. aureus 17422 was the weakest, but as compared with S. aureus 17431, S. aureus 18541-2, S. aureus 18558, S. aureus 18565 and S. aureus 18719, the difference was not statistically significant. CONCLUSION Congo red plate method can detect the S. aureus strains of BF formation. All the homologous S
Clonal Structure and Characterization of Staphylococcus aureus Strains from Invasive Infections in Paediatric Patients from South Poland: Association between Age, spa Types, Clonal Complexes, and Genetic Markers.
Ilczyszyn, Weronika M; Sabat, Artur J; Akkerboom, Viktoria; Szkarlat, Anna; Klepacka, Joanna; Sowa-Sierant, Iwona; Wasik, Barbara; Kosecka-Strojek, Maja; Buda, Aneta; Miedzobrodzki, Jacek; Friedrich, Alexander W
The aim of current study was to examine clonal structure and genetic profile of invasive Staphylococcus aureus isolates recovered from infants and children treated at the Jagiellonian University Children's Hospital of Krakow, Poland. The 107 invasive S. aureus isolates, collected between February 2012 and August 2014, were analysed retrospectively. Antimicrobial susceptibility testing, spa typing and DNA microarray analysis were performed to determine clonal distribution, diversity and gene content in regard to patients characteristics. In total, 107 isolates were recovered from 88 patients with clinical symptoms of invasive bacterial infection. The final set of 92 non-duplicate samples included 38 MRSA isolates. Additionally, a set of 54 S. aureus isolates collected during epidemiological screening was genotyped and analysed. There were 72 healthcare-associated (HCA) and 20 community-onset (CO) infection events caused by 33 and 5 MRSA isolates, respectively. The majority of isolates were affiliated with the major European clonal complexes CC5 (t003, spa-CC 002), CC45 (spa-CC 015), CC7 or CC15 (t084, t091, spa-CC 084). Two epidemic clones (CC5-MRSA-II or CC45-MRSA-IV) dominated among MRSA isolates, while MSSA population contained 15 different CCs. The epidemiological screening isolates belonged to similar genetic lineages as those collected from invasive infection cases. The HCA infection events, spa types t003, t2642 or CC5 were significantly associated with infections occurring in neonates and children under 5 years of age. Moreover, carriage of several genetic markers, including erm(A), sea (N315), egc-cluster, chp was significantly higher in isolates obtained from children in this age group. The spa types t091 and t008 were underrepresented among patients aged 5 years or younger, whereas spa type t008, CC8 and presence of splE was associated with infection in children aged 10 years or older. The HCA-MRSA strains were most frequently found in children under 5
Monecke, Stefan; Coombs, Geoffrey W; Pearson, Julie; Hotzel, Helmut; Slickers, Peter; Ehricht, Ralf
A West Australian methicillin-resistant Staphylococcus aureus strain (WA MRSA-59) was characterized by microarray and sequencing. Its pseudo-staphylococcal cassette chromosome mec (SCCmec) element comprised dcs, Q9XB68-dcs, mvaS-SCC, Q5HJW6, dru, ugpQ, ydeM, mecA-mecR-mecI, txbi mecI, tnp IS431, copA2-mco (copper resistance), ydhK, arsC-arsB-arsR (arsenic resistance), open reading frame PT43, and per-2. Recombinase genes, xylR (mecR2), and PSM-mec (phenol-soluble modulin) were absent. We suggest that mec complex A should be split into two subtypes. One harbors PSM-mec and xylR (mecR2). It is found in SCCmec types II, III, and VIII. The second subtype, described herein, is present in WA MRSA-59 and some coagulase-negative staphylococci. PMID:26349822
Antimicrobial activity of honey of stingless bees, tiúba (Melipona fasciculata) and jandaira (Melipona subnitida) compared to the strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa
Tenório, Eleuza Gomes; de Jesus, Natália Rocha; Nascimento, Adenilde Ribeiro; Teles, Amanda Mara
This study aimed to investigate the antimicrobial activity of honeys of stingless bees produced in Maranhão, tiúba (Melipona fasciculata) and jandaira (Melipona subnitida), opposite the strains of pathogenic bacteria, namely, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The honey samples were collected from different regions of Maranhão. Of the 17 samples collected, twelve samples were honey M. fasciculata and five were honey M. subnitida. We used the Kirby-Bauer method, and the technique of agar disk diffusion through the extent of inhibition in milimetros. Results were negative for all samples from M. fasciculata. However, the tests for M. subnitida demonstrated bacteriostatic halos ranging from 12 to 32,6mm.
Interactions of Quinupristin-Dalfopristin with Eight Other Antibiotics as Measured by Time-Kill Studies with 10 Strains of Staphylococcus aureus for Which Quinupristin-Dalfopristin Alone Was Not Bactericidal
Fuchs, Peter C.; Barry, Arthur L.; Brown, Steven D.
Quinupristin-dalfopristin (Q-D) and eight other antimicrobial agents were tested alone and in combination with Q-D in time-kill studies against 10 strains of macrolide-lincosamide-streptogramin B-resistant Staphylococcus aureus. Although Q-D is normally a bactericidal drug, it was only bacteriostatic for these isolates. Gentamicin alone was bactericidal against 7 of the 10 strains, and Q-D did not alter that killing effect. However, when vancomycin, cefepime, ceftazidime, imipenem, piperacill...
Hedin, Göran; Fang, Hong
Thirty-nine methicillin-resistant Staphylococcus aureus (MRSA) isolates with diverse genetic backgrounds and two reference strains were correctly identified as S. aureus on CHROMagar MRSA and S. aureus ID media. Growth inhibition on CHROMagar MRSA was noted. A combination of cefoxitin disk and S. aureus ID was found suitable for rapid MRSA screening.
Pelletier, Dale A [ORNL; Morrell-Falvey, Jennifer L [ORNL; Karve, Abhijit A [ORNL; Lu, Tse-Yuan S [ORNL; Tschaplinski, Timothy J [ORNL; Tuskan, Gerald A [ORNL; Chen, Jay [ORNL; Martin, Madhavi Z [ORNL; Jawdy, Sara [ORNL; Weston, David [ORNL; Doktycz, Mitchel John [ORNL; Schadt, Christopher Warren [ORNL
Colonization of plants by nonpathogenic Pseudomonas fluorescens strains can confer enhanced defense capacity against a broad spectrum of pathogens. Few studies, however, have linked defense pathway regulation to primary metabolism and physiology. In this study, physiological data, metabolites, and transcript profiles are integrated to elucidate how molecular networks initiated at the root-microbe interface influence shoot metabolism and whole-plant performance. Experiments with Arabidopsis thaliana were performed using the newly identified P. fluorescens GM30 or P. fluorescens Pf-5 strains. Co-expression networks indicated that Pf-5 and GM30 induced a subnetwork specific to roots enriched for genes participating in RNA regulation, protein degradation, and hormonal metabolism. In contrast, only GM30 induced a subnetwork enriched for calcium signaling, sugar and nutrient signaling, and auxin metabolism, suggesting strain dependence in network architecture. In addition, one subnetwork present in shoots was enriched for genes in secondary metabolism, photosynthetic light reactions, and hormone metabolism. Metabolite analysis indicated that this network initiated changes in carbohydrate and amino acid metabolism. Consistent with this, we observed strain-specific responses in tryptophan and phenylalanine abundance. Both strains reduced host plant carbon gain and fitness, yet provided a clear fitness benefit when plants were challenged with the pathogen P. syringae DC3000.
Immunoglobulin Fc receptors in clinical strains of Staphylococcus aureus do not confer resistance to Phagocytosis in an in vitro assay Los receptores Fc para inmunoglobulinas en cepas clínicas de Staphylococcus aureus no confieren resistencia a la fagocitosis in vitro
Full Text Available Staphylococcus aureus binds Immunoglobulin G (IgG on its external surface due to the presence of specific receptors for the Fc domain of this immunoglobulin. This mechanism represents a kind of camouflage against phagocytic cells. In order to confirm that possibility an in vitro evaluation of the phagocytic activity of leukocytes polymorpho-nuclear (PMN against strains of Staphylococcus aureus was done, comparing 18 strains isolated from clinical samples and 16 from healthy individuals. The presence of Fc receptors was evaluated by haemagglutination (HA with erythrocytes group A after incubation of the strains with IgG anti blood group A. Phagocytosis of S. aureus was carried out by mixing live bacteria with a suspension of human PMN and incubating at 37 °C for 1 h; survivors were counted as colony forming units by plating. The strains from clinical specimens showed higher HA than those from healthy individuals (p = 0.01; but the former were killed more efficiently than the latter (80-90% and 40%, respectively. It is may be possible that S. aureus showed different behavior in vivo, where could express other virulence factors to prevent the action of phagocytes.Staphylococcus aureus liga inmunoglobulinas G (IgG a su superficie externa debido a la presencia de receptores para el dominio Fc de esas inmunoglobulinas. Este mecanismo representa una clase de camuflage contra células fagocíticas. Para confirmar tal posibilidad se realizó una evaluación in vitro de la actividad fagocítica de leucocitos polimorfonucleares (PMN contra cepas de Staphylococcus aureus, comparando 18 cepas aisladas de casos clínicos y 16 de individuos sanos. La presencia de receptores fue evaluada por hemaglutinación (HA con eritrocitos grupo A luego que las cepas fueron incubadas con IgG anti grupo sanguíneo A. La fagocitosis de S. aureus fue realizada mezclando células vivas con una suspensión de PMN e incubada a 37 °C por una hora; las bacterias sobrevivientes
Full Text Available Aim and Background: Staphylococcus aureus is a major human pathogen that also causes important infections in cattle and sheep. The present study aimed to test genetic diversity among strains of S. aureus isolated from cattle (n=34 and humans (n=22 by DNA typing. Materials and Methods: Fluorescent amplified fragment length polymorphism (FAFLP is the genotyping tool used in the study. The presence of the mecA and Panton-Valentine leukocidin (PVL genes among these strain groups was also checked. Results: A dendrogram deduced from FAFLP showed that all the strains clustered into 10 groups (A-J with a relative genetic divergence of less than 8%. Sixty-seven percent of the isolates from bovine sources clustered together in two clades (A and H, while another major cluster with 13 isolates (59% (Cluster G had all strains from a human host. The remaining strains from both the hosts clustered independently into smaller clusters with the exception of two strains of human origin, which clustered along with a bovine cluster. Thirteen strains belonging to cluster G were highly clonal. About 77% of strains obtained from human infections were methicillin-resistant S. aureus (MRSA, whereas only 29% of strains from bovine origin were MRSA. Only three strains from human origin showed PVL positive, while no strain from cattle had PVL genes. The complete absence of PVL genes in all the bovine strains in the study appears to be significant. Conclusions: FAFLP can be successfully applied to assess the genetic relationship of S. aureus isolates from different hosts. The study also provided the valuable epidemiological data on S. aureus from bovine sources in India, which is lacking.
王若飞; 丁天鹏; 李定宪; 龚英英; 周志虹; 夏云昆
OBJECTIVE To investigate the clinical distribution and drug resistance of Staphylococcus aureus(SAU) isolated from the hospitalized patients during the past three years so as to guide the reasonable use of antibiotics. METHODS The clinical distribution and antimicrobial resistance of 196 strains of S. aureus were investigated and analyzed. The bacterial culture and identification of S. aureus strains were performed according to National Guide to Clinical Laboratory Operation Procedures. The antimicrobial susceptibility testing was performed by KB method recommended by CLSI. RESULTS Of 196 strains of S. aureus, 48. 5% were methicillin-resistant S. aureus (MRSA), and 51. 5% were methicillin-susceptible S. aureusi MSSA). Of 95 strains of MRSA, isolation rate was relatively high in the ICU, respiratory department, or the neurology department, and was low in the pediatrics department. S. aureus strains varied in the drug resistance to various commonly used antibiotics. The drug resistance rate of the MRSA strains was higher than the MSSA strains. CONCLUSION The drug resistance of S. aureusstrains is serious. It is very important to enhance the monitoring of drug resistance and rational application of antibiotics.%目的 分析近3年医院住院患者金黄色葡萄球菌(SAU)分离株的临床分布及耐药性,为指导临床治疗SAU感染合理使用抗菌药物提供帮助.方法 对196株SAU的分布及耐药性进行调查分析,严格按照《全国临床检验操作规程》进行SAU培养与鉴定,采用CLSI推荐的KB法进行药敏试验.结果 196株SAU中,48.5％为耐甲氧西林金黄色葡萄球菌(MRSA),51.5％为甲氧西林敏感金黄色葡萄球菌(MSSA)；在95株MRSA中,ICU、呼吸科、神经内科检出率较高,儿科检出率相对较低；SAU对多种常用抗菌药物均产生了不同程度的耐药；MRSA的耐药率均高于MSSA.结论 SAU引起的耐药现象严重,加强耐药性监测,合理使用抗菌药物非常重要.
Produção de enterotoxinas e da toxina da síndrome do choque tóxico por cepas de Staphylococcus aureus isoladas na mastite bovina Production of enterotoxins and toxic shock syndrome toxin by Staphylococcus aureus strains isolated from bovine mastitis
A. Nader Filho
Full Text Available A total of 72 strains of Staphylococcus aureus were examined for the production of staphylococcal enterotoxins (SE A, B, C, D and toxic shock syndrome toxin (TSST-1. The strains were isolated from milk samples from cows with mastitis in dairy herds of São Paulo State, Brazil. Off 72 isolates, 38 (52.8% produced SEA, 38 (52.8% SEB, 32 (44.4% SED, 28 (38.9% SEC and 27 (37.5% TSST-1. From the 72 strains, 66 (91.7% produced, at least, one or more toxin, including TSST-1.
Full Text Available Abstract Background Infections caused by community-associated strains of methicillin-resistant Staphylococcus aureus (CA-MRSA are associated with a marked and prolonged host inflammatory response. In a sepsis simulation model, we tested whether the anesthetic ketamine inhibits the macrophage TNF response to antibiotic-exposed CA-MRSA bacteria via its antagonism of N-methyl-D-aspartate (NMDA receptors. RAW264.7 cells were stimulated for 18 hrs with 105 to 107 CFU/mL inocula of either of two prototypical CA-MRSA isolates, USA300 strain LAC and USA400 strain MW2, in the presence of either vancomycin or daptomycin. One hour before bacterial stimulation, ketamine was added with or without MK-801 (dizocilpine, a chemically unrelated non-competitive NMDA receptor antagonist, APV (D-2-amino-5-phosphono-valerate, a competitive NMDA receptor antagonist, NMDA, or combinations of these agents. Supernatants were collected and assayed for TNF concentration by ELISA. Results RAW264.7 cells exposed to either LAC or MW2 in the presence of daptomycin secreted less TNF than in the presence of vancomycin. The addition of ketamine inhibited macrophage TNF secretion after stimulation with either of the CA-MRSA isolates (LAC, MW2 in the presence of either antibiotic. The NMDA inhibitors, MK-801 and APV, also suppressed macrophage TNF secretion after stimulation with either of the antibiotic-exposed CA-MRSA isolates, and the effect was not additive or synergistic with ketamine. The addition of NMDA substrate augmented TNF secretion in response to the CA-MRSA bacteria, and the addition of APV suppressed the effect of NMDA in a dose-dependent fashion. Conclusions Ketamine inhibits TNF secretion by MRSA-stimulated RAW264.7 macrophages and the mechanism likely involves NMDA receptor antagonism. These findings may have therapeutic significance in MRSA sepsis.
Comparison of Virulence Gene Identification, Ribosomal Spacer PCR, and Pulsed-Field Gel Electrophoresis for Typing of Staphylococcus aureus Strains Isolated from Cases of Subclinical Bovine Mastitis in the United States.
Adkins, Pamela R F; Middleton, John R; Fox, Lawrence K
Staphylococcus aureus is one of the most important pathogens causing contagious mastitis in dairy cattle worldwide. The objectives of this study were to determine if recently described S. aureus genotype B was present among previously characterized isolates from cases of bovine intramammary infection in the United States and to compare pulsed-field gel electrophoresis (PFGE) to the combination of ribosomal spacer PCR (RS-PCR) and virulence gene identification for typing of S. aureus strains. The hypothesis was that isolates that were previously characterized as contagious would be identified as genotype B and that the results of the two strain-typing methods would be comparable. Isolates were selected from a collection of S. aureus isolates from eight dairy farms. Mammary quarter milk somatic cell count (SCC) and N-acetyl-β-d-gluconaminidase (NAGase) activity data were known and used to evaluate strain pathogenicity. RS-PCR was performed with conventional gel electrophoresis, and PCR was used for toxin gene identification. RS-PCR patterns were associated with a specific virulence gene pattern, as previously reported. Five RS-PCR banding patterns were identified. None of the isolates were characterized as genotype B. No association between RS-PCR types and milk SCC was found; however, NAGase activity was significantly higher in milk from mammary glands infected with RS-PCR banding type 1 (RSP type 1) than in milk from those infected with RSP type 2. The discriminatory power values were 1.0 and 0.46 for PFGE and RS-PCR, respectively. These data suggest that genotype B may have a limited geographic distribution and that PFGE is more discriminatory than RS-PCR performed with conventional gel electrophoresis for typing of S. aureus isolates of bovine origin. PMID:27194685
Jelsbak, Lotte; Ingmer, Hanne; Valihrach, Lukás; Cohn, Marianne Thorup; Christiansen, Mie H.G.; Kallipolitis, Birgitte H.; Frees, Dorte
The Clp ATPases (Hsp100) constitute a family of closely related proteins that have protein reactivating and remodelling activities typical of molecular chaperones. In Staphylococcus aureus the ClpX chaperone is essential for virulence and for transcription of spa encoding Protein A. The present...
Carro, David; Bartra, Enric; Piña, Benjamín
Yeast strains isolated from the wild may undergo karyotype changes during vegetative growth, a characteristic that compromises their utility in genetic improvement projects for industrial purposes. Karyotype instability is a dominant trait, segregating among meiotic derivatives as if it depended upon only a few genetic elements. We show that disrupting the RAD52 gene in a hypervariable strain partially stabilizes its karyotype. Specifically, RAD52 disruption eliminated recombination at telome...
Comparative Activities of Clinafloxacin, Grepafloxacin, Levofloxacin, Moxifloxacin, Ofloxacin, Sparfloxacin, and Trovafloxacin and Nonquinolones Linozelid, Quinupristin-Dalfopristin, Gentamicin, and Vancomycin against Clinical Isolates of Ciprofloxacin-Resistant and -Susceptible Staphylococcus aureus Strains
Jones, Mark E.; Visser, Maarten R.; Klootwijk, Miriam; Heisig, Peter; Verhoef, Jan; Schmitz, Franz-Josef
The activities of eight fluoroquinolones and linezolid, quinupristin-dalfopristin (Synercid), gentamicin, and vancomycin were tested against 96 ciprofloxacin-susceptible and 205 ciprofloxacin-resistant Staphylococcus aureus strains. Overall, clinafloxacin, followed by moxifloxacin and trovafloxacin, was the most active quinolone tested. For all isolates, linezolid and quinupristin-dalfopristin showed activities that were at least comparable to vancomycin, with no cross-resistance to any other...
Tuchina, Elena S.; Petrov, Pavel O.; Ratto, Fulvio; Centi, Sonia; Pini, Roberto; Tuchin, Valery V.
The effect of NIR laser radiation (808 nm) on methicillin-sensitive and methicillin resistant strains of Staphylococcus aureus incubated with gold nanorods is studied. Nanorods having length of 44 (± 4) nm and diameter of 10 (± 3) nm with the absorption maximum in the NIR (800 nm), functionalized with human immunoglobulins IgA and IgG, were synthesized and used in the studies. The killing ability up to 97% of the microorganism populations by using this nanotechnology was shown.
Nicholas P Vitko; Richardson, Anthony R.
Staphylococcus aureus is an important bacterial pathogen in the hospital and community settings, especially Staphylococcus aureus clones that exhibit methicillin-resistance (MRSA). Many strains of S. aureus are utilized in the laboratory, underscoring the genetic differences inherent in clinical isolates. S. aureus grows quickly at 37°C with aeration in rich media (e.g. BHI) and exhibits a preference for glycolytic carbon sources. Furthermore, S. aureus has a gold pigmentation, exhibits β-hem...
Nicholas J Patterson
Full Text Available Staphylococcus aureus, sequence type (ST 398, is an emerging pathogen and the leading cause of livestock-associated methicillin-resistant Staphylococcus aureus infections in Europe and North America. This strain is characterised by high promiscuity in terms of host species and also lacks several traditional S. aureus virulence factors. This does not however explain the apparent ease with which it crosses species-barriers. Recently, TIR-domain containing proteins (Tcps inhibitng the innate immune response were identified in some Gram-negative bacteria. Here we report the presence of two proteins, S. aureus TIR-like Protein 1 (SaTlp1 and S. aureus TIR-like Protein 2 (SaTlp2, expressed by ST398 which contain Domain of Unknown Function 1863 (DUF1863, similar to the Toll/IL-1 receptor (TIR domain. In contrast to the Tcps in Gram-negative bacteria, our data suggest that SaTlp1 and SaTlp2 increase activation of the transcription factor NF-κB as well as downstream pro-inflammatory cytokines and immune effectors. To assess the role of both proteins as potential virulence factors knock-out mutants were created. These showed the potential for a slightly increased survival rate in a murine infectious model compared to the wild-type strain at one dose, but the data did not reach level of significance. Our data suggest that both proteins may act as factors contributing to the enhanced ability of ST398 to cross species-barriers.
Tara C Smith
Full Text Available BACKGROUND: Recent research has demonstrated that many swine and swine farmers in the Netherlands and Canada are colonized with MRSA. However, no studies to date have investigated carriage of MRSA among swine and swine farmers in the United States (U.S.. METHODS: We sampled the nares of 299 swine and 20 workers from two different production systems in Iowa and Illinois, comprising approximately 87,000 live animals. MRSA isolates were typed by pulsed field gel electrophoresis (PFGE using SmaI and EagI restriction enzymes, and by multi locus sequence typing (MLST. PCR was used to determine SCCmec type and presence of the pvl gene. RESULTS: In this pilot study, overall MRSA prevalence in swine was 49% (147/299 and 45% (9/20 in workers. The prevalence of MRSA carriage among production system A's swine varied by age, ranging from 36% (11/30 in adult swine to 100% (60/60 of animals aged 9 and 12 weeks. The prevalence among production system A's workers was 64% (9/14. MRSA was not isolated from production system B's swine or workers. Isolates examined were not typeable by PFGE when SmaI was used, but digestion with EagI revealed that the isolates were clonal and were not related to common human types in Iowa (USA100, USA300, and USA400. MLST documented that the isolates were ST398. CONCLUSIONS: These results show that colonization of swine by MRSA was very common on one swine production system in the midwestern U.S., suggesting that agricultural animals could become an important reservoir for this bacterium. MRSA strain ST398 was the only strain documented on this farm. Further studies are examining carriage rates on additional farms.
Malachowa, Natalia; Kobayashi, Scott D.; Porter, Adeline R.; Braughton, Kevin R.; Scott, Dana P.; Gardner, Donald J.; Missiakas, Dominique M.; Schneewind, Olaf; DeLeo, Frank R.
Staphylococcus aureus produces numerous factors that facilitate survival in the human host. S. aureus coagulase (Coa) and von Willebrand factor-binding protein (vWbp) are known to clot plasma through activation of prothrombin and conversion of fibrinogen to fibrin. In addition, S. aureus clumping factor A (ClfA) binds fibrinogen and contributes to platelet aggregation via a fibrinogen- or complement-dependent mechanism. Here, we evaluated the contribution of Coa, vWbp and ClfA to S. aureus pathogenesis in a rabbit model of skin and soft tissue infection. Compared to skin abscesses caused by the Newman wild-type strain, those caused by isogenic coa, vwb, or clfA deletion strains, or a strain deficient in coa and vwb, were significantly smaller following subcutaneous inoculation in rabbits. Unexpectedly, we found that fibrin deposition and abscess capsule formation appear to be independent of S. aureus coagulase activity in the rabbit infection model. Similarities notwithstanding, S. aureus strains deficient in coa and vwb elicited reduced levels of several proinflammatory molecules in human blood in vitro. Although a specific mechanism remains to be determined, we conclude that S. aureus Coa, vWbp and ClfA contribute to abscess formation in rabbits. PMID:27336691
Staphylococcus aureus can bind soluble collagen in a specific, saturable manner. We have previously shown that some variability exists in the degree of collagen binding between different strains of heat-killed, formaldehyde-fixed S. aureus which are commercially available as immunologic reagents. The present study demonstrates that live S. aureus of the Cowan 1 strain binds amounts of collagen per organism equivalent to those demonstrated previously in heat-killed, formaldehyde-fixed bacteria but has an affinity over 100 times greater, with Kd values of 9.7 X 10(-11) M and 4.3 X 10(-8) M for live and heat-killed organisms, respectively. Studies were also carried out with S. aureus killed by ionizing radiation, since this method of killing the organism seemed less likely to alter the binding moieties on the surface than did heat killing. Bacteria killed by exposure to gamma radiation bound collagen in a manner essentially indistinguishable from that of live organisms. Binding of collagen to irradiated cells of the Cowan 1 strain was rapid, with equilibrium reached by 30 min at 22 degrees C, and was fully reversible. The binding was not inhibited by fibronectin, fibrinogen, C1q, or immunoglobulin G, suggesting a binding site for collagen distinct from those for these proteins. Collagen binding was virtually eliminated in trypsin-treated organisms, indicating that the binding site has a protein component. Of four strains examined, Cowan 1 and S. aureus ATCC 25923 showed saturable, specific binding, while strains Woods and S4 showed a complete lack of binding. These results suggest that some strains of S. aureus contain high-affinity binding sites for collagen. While the number of binding sites per bacterium varied sixfold in the two collagen-binding strains, the apparent affinity was similar
FOSTER, TIMOTHY JAMES
PUBLISHED There has been some debate about the disease-invoking potential of Staphylococcus aureus strains and whether invasive disease is associated with particularly virulent genotypes, or "superbugs." A study in this issue of the JCI describes the genotyping of a large collection of nonclinical, commensal S. aureus strains from healthy individuals in a Dutch population. Extensive study of their genetic relatedness by amplified restriction fragment typing and comparison with strains that...
Nielsen, Kim Lau; Niordson, Christian Frithiof
A numerical model formulation of the higher order flow theory (rate-independent) by Fleck and Willis [2009. A mathematical basis for strain-gradient plasticity theory – part II: tensorial plastic multiplier. Journal of the Mechanics and Physics of Solids 57, 1045-1057.], that allows for elastic......–plastic loading/unloading and the interaction of multiple plastic zones, is proposed. The predicted model response is compared to the corresponding rate-dependent version of visco-plastic origin, and coinciding results are obtained in the limit of small strain-rate sensitivity. First, (i) the evolution of a...... single plastic zone is analyzed to illustrate the agreement with earlier published results, whereafter examples of (ii) multiple plastic zone interaction, and (iii) elastic–plastic loading/unloading are presented. Here, the simple shear problem of an infinite slab constrained between rigid plates is...
Haslund, P; Bangsgaard, N; Jarløv, J O;
BACKGROUND: The role of bacterial infections in hand eczema (HE) remains to be assessed. OBJECTIVES: To determine the prevalence of Staphylococcus aureus in patients with HE compared with controls, and to relate presence of S. aureus, subtypes and toxin production to severity of HE. METHODS......: Bacterial swabs were taken at three different visits from the hand and nose in 50 patients with HE and 50 controls. Staphylococcus aureus was subtyped by spa typing and assigned to clonal complexes (CCs), and isolates were tested for exotoxin-producing S. aureus strains. The Hand Eczema Severity Index...... was used for severity assessment. RESULTS: Staphylococcus aureus was found on the hands in 24 patients with HE and four controls (P aureus was found to be related to increased severity of the eczema (P aureus types on the hands...
Does nasal cocolonization by methicillin-resistant coagulase-negative staphylococci and methicillin-susceptible Staphylococcus aureus strains occur frequently enough to represent a risk of false-positive methicillin-resistant S. aureus determinations by molecular methods?
Becker, Karsten; Pagnier, Isabelle; Schuhen, Brigitte; Wenzelburger, Frauke; Friedrich, Alexander W; Kipp, Frank; Peters, Georg; von Eiff, Christof
By analyzing the colonization of the anterior nares in cardiothoracic surgery patients on admission, nasal cocolonization by methicillin-susceptible Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci was detected in 8/235 (3.4%) specimens. Consequently, in a low-methici
Atividade antibacteriana de óleos essenciais de plantas frente a linhagens de Staphylococcus aureus e Escherichia coli isoladas de casos clínicos humanos Antibacterial activity of plant essential oils against Staphylococcus aureus and Escherichia coli strains isolated from human specimens
Full Text Available A ação antibacteriana in vitro de óleos essenciais de seis plantas foi verificada por meio da Concentração Inibitória Mínima (CIM=%v/v pela diluição dos óleos em meio de cultura Mueller Hinton Agar, frente a linhagens de Staphylococcus aureus (n=16 e Escherichia coli (n=16 isoladas de casos clínicos humanos, além de 1 amostra padrão ATCC para cada espécie (Sa ATCC 25923 e Ec ATCC 25922, e determinação de curvas de sobrevivência em concentrações equivalentes a CIM90% dos respectivos óleos. O óleo essencial de canela foi o mais eficiente, com valores de CIM90% de 0,047 e 0,09 para S. aureus e E. coli respectivamente, enquanto gengibre (0,09, cravo da índia (0,095 e capim cidreira (0,1 apresentaram eficiências semelhantes para S. aureus. Frente a E. coli, os óleos de gengibre (0,52 e capim cidreira (0,55 foram equivalentes quanto à eficiência. De acordo com as curvas de sobrevivência, foi possível verificar também que os valores de CIM90% obtidos podem ser tanto bactericidas ou bacteriostáticas de acordo com a bactéria testada. Em conclusão, verificou-se que os óleos essenciais testados foram efetivos no controle do desenvolvimento bacteriano, sendo o potencial antimicrobiano diferente em função da espécie bacteriana testada, sendo que a bactéria Gram positiva (S. aureus mostrou-se mais susceptível aos óleos testados que a Gram negativa (E. coli.The in vitro antibacterial activity of essential oils from six plants was verified through minimal inhibitory concentration (MIC=%v/v, determined by diluting the oils in culture medium Mueller Hinton Agar, against Staphylococcus aureus (n=16 and Escherichia coli (n=16 strains isolated from human clinical specimens, besides one standard ATCC strain for each species (Sa 25923 and Ec 25922. Time-kill curves were also determined at concentrations equivalent to MIC90% for the respective oils. Cinnamon oil was the most efficient, with MIC90% values of 0.047 and 0.09 against
Rossi, R.; Roubíček, Tomáš
Roč. 74, č. 10 (2011), s. 3159-3190. ISSN 0362-546X R&D Projects: GA ČR GAP201/10/0357 Institutional research plan: CEZ:AV0Z20760514 Keywords : adhesive contact * nonlinear heat equation * rate-independence Subject RIV: BA - General Mathematics Impact factor: 1.536, year: 2011 http://www.sciencedirect.com/science/article/pii/S0362546X11000496
Soni, Isha; Chakrapani, Harinath; Chopra, Sidharth
Staphylococcus aureus subsp. aureus ATCC 29213 is one of the most commonly used strains in drug discovery research and for quality control. We report the completed draft genome sequence for the strain.
Full Text Available In order to analyse the impact of oxacillin resistance on the mortality of Staphylococcus aureus bacteremia, and to assess the antimicrobial susceptibility of community-acquired strains in two large university hospitals (the Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo and the Instituto Central do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, we carried out a four-month-long prospective cohort study, which included 163 consecutive cases of S. aureus bacteremia. Of these, 140 (85.9% were hospital-acquired, 9 (5.5% were community-acquired and 14 (8.6% were of indeterminate origin. No cases of community-acquired infection by oxacillin-resistant S. aureus was identified. Among hospital-acquired infections, oxacillin-resistant S. aureus was responsible for 64.3% of cases. Mortality up to 15 days after diagnosis of bacteremia was 27% (18/67 for infections caused by susceptible strains and 33% (32/96 for infections caused by oxacillin-resistant strains (p=0.10. The following independent risk factors for the acquisition of oxacillin-resistant S. aureus were identified in multiple logistical regression analysis: age over 60 years, use of corticoids; presence of a central vascular catheter, and previous use of antibiotics.
Intracellular Activity of Antibiotics in a Model of Human THP-1 Macrophages Infected by a Staphylococcus aureus Small-Colony Variant Strain Isolated from a Cystic Fibrosis Patient: Pharmacodynamic Evaluation and Comparison with Isogenic Normal-Phenotype and Revertant Strains▿ †
Nguyen, Hoang Anh; Denis, Olivier; Vergison, Anne; Theunis, Anne; Tulkens, Paul M.; Struelens, Marc J.; Van Bambeke, Françoise
Small-colony variant (SCV) strains of Staphylococcus aureus show reduced antibiotic susceptibility and intracellular persistence, potentially explaining therapeutic failures. The activities of oxacillin, fusidic acid, clindamycin, gentamicin, rifampin, vancomycin, linezolid, quinupristin-dalfopristin, daptomycin, tigecycline, moxifloxacin, telavancin, and oritavancin have been examined in THP-1 macrophages infected by a stable thymidine-dependent SCV strain in comparison with normal-phenotype...
杨再昌; 杨小生; 王伯初; 郝小江
The present work was carried out to screen the effect of the traditional Chinese medicine in combination with the antibiotics to identify systems, which might be used to improve the efficiency of the antibiotics used. The inhibitory effects of ethanolic extracts of 14 traditional Chinese medicines and their combinations with four antibiotics on the resistance of Staphylococcus aureus were checked. Methicillin resistant S. aureus (MRSA), which was isolated from patient,and a standard strain of S. aureus were used. M. fortunei , Portulaca oleracea, M. officinalis , Platycodon grandifiorum, Leonurus heteropyllus , Prunella vulgaris were effective on improving the inhibitory effects of both the resistant and sensitive S. aureus when combined with four antibiotics. E. helioscopia , Verbena officinalis , A . carmichaeli , Plantago asiatica, Eucommia ulmoides , Datura metel showed no synergistic activity. Combinations of penicillin and ceftriaxone with Paeania lactifiora on both strains showed significant improvement in the antimicrobial activity. A. yunnanensis combined with ciprofloxacin exhibited powerful antimicrobial activity. It is a valuable practice to screen traditional Chinese medicines combined with antibiotics against S. aureus.%用耐甲氧西林的金葡菌(MRSA)及金葡菌标准株为试验菌,测定了14种中药的乙醇提取物与4种抗菌药物的联合抗菌作用.狭叶十大功劳、马齿苋、厚朴、桔梗、益母草、夏枯草与4种抗菌药物对两株金葡菌存在联合作用;泽漆、马鞭草、乌头、车前草、白曼陀罗、杜仲与4种抗菌药物无联合作用;芍药与青霉素、头孢曲松产生很好的联合效应;鸡骨常山能提高环丙沙星的抗菌作用.筛选与抗菌素有联合作用的中草药对抑制金黄色葡萄球菌是可行的.
Holmes, Natasha E.; Johnson, Paul D. R.; Howden, Benjamin P.
Vancomycin has been used successfully for over 50 years for the treatment of Staphylococcus aureus infections, particularly those involving methicillin-resistant S. aureus. It has proven remarkably reliable, but its efficacy is now being questioned with the emergence of strains of S. aureus that display heteroresistance, intermediate resistance, and, occasionally, complete vancomycin resistance. More recently, an association has been established between poor outcome and infections with strain...
Rahman, M.; Noble, W. C.; Cookson, B
The spread of two strains of Staphylococcus aureus with high level resistance to mupirocin is described. The resistance proved to be easily transferred to other S. aureus strains by filter mating experiments and on the skin of mice. No plasmid band corresponding to the resistance could be demonstrated by agarose gel electrophoresis or by caesium chloride gradient centrifugation but cleavage of 'chromosomal' DNA from resistant recipients showed bright bands of DNA absent from sensitive controls.
Zhang, Yufeng; Yu, Yongqin; Du, Chenlin; Ruan, Shuangchen; Chen, Xue; Huang, Quandong; Zhou, Wen
A simple Mach-Zehnder interferometer (MZI) was presented for high temperature measurement. The device was composed of a short segment of suspended-core fiber (SCF) sandwiched between two standard single mode fibers (SMFs) with a misaligned splicing joint. Lower temperature measurements were firstly carried out from room temperature to 190 °C, and the obtained sensitivity at the wavelength of 1465 nm was 25.82 pm/°C. However, a nonlinear response was further achieved for high-temperature sensing up to 1000 °C. Between 20 and 200 °C, the sensitivity was just 24.24 pm/°C at the wavelength of 1457 nm, whereas a higher sensitivity of 53.87 pm/°C was acquired in the range of 200-1000 °C. In addition, the strain cross-sensitivity was extremely low. As a result, the device can be developed as a strain-independent temperature sensor and become an excellent candidate for high temperature measurement.
The effects of u.v. irradiation on the survival of Staphylococcus aureus and its phage phi11 were studied. The recA and uvr mutations affected their survival like synonymous mutations in Escherichia coli. Weigle reactivation (W-reactivation) of phi11 occurred in wild-type S. aureus and in a uvr mutant. Reactivation was recA-dependent and was accompanied by u.v.-induced mutagenesis in a temperature-sensitive mutant of phi11. Bacterial mutation to streptomycin resistance was induced by u.v. and was also recA-dependent. In S. aureus, as in E. coli, u.v. was a more effective mutagen in the uvr genetic background. However, a dose-squared response for u.v.-induced mutation of wild-type and uvr strains of S. aureus to streptomycin resistance, and of a trp auxotroph to tryptophan independence, was found only with u.v. doses below 1 J m-2. In relation to the Uvr mechanism of DNA repair, u.v. mutagenesis in S. aureus may involve both repairable and non-repairable lesions. As in E. Coli, the uvr genetic background reduced the u.v. dose required for maximal W-reactivation of u.v.-irradiated phage. However, there was no enhancement of W-reactivation by post-irradiation broth incubation of S. aureus. The results are compatible with a non-inducible mechanism for this phenomenon. (author)
Detection of different Staphylococcus aureus strains in bovine milk from subclinical mastitis using PCR and routine techniques Detecção de diferentes cepas de Staphylococcus aureus de mastite bovina subclínica através da técnica de PCR e técnicas tradicionais
Full Text Available Contamination of fresh milk with Staphylococcus aureus was assessed comparatively through routine phenotypic (coagulase tube test and coagulase slide test and genotypic (PCR screening of 128 S. aureus strains isolated from 555 milk samples. These samples were collected from 362 cows with subclinical mastitis, hosted in different dairy herds at various locations of the Northern and Northeastern rural areas of the State of Rio de Janeiro, 39.7% of which were CMT-positive. All S. aureus isolates tested positive for the presence of the coagulase gene by PCR and the isolates could be grouped into four distinct classes according to the size of the PCR product. The strains also yielded variable results when assayed with coagulase test. Taken together, these data indicate the existence of extensive polymorphism at the coagulase gene locus in the genus Staphylococcus and exemplifies the extent of molecular and phenotypic heterogeneity associated with the strains circulating in rural herds.Quinhentas e cinqüenta e cinco amostras de leite, provenientes de 362 vacas com mastite subclínica em diferentes propriedades rurais do Estado do Rio de Janeiro, Brasil, de 1995 a 1997, foram submetidas ao teste "Califórnia Mastitis Test" (CMT. 39,7% das amostras foram positivas, das quais foram isoladas 128 cepas de Staphylococcus aureus. Todas as cepas isoladas foram positivas para o gene da coagulase utilizando a técnica de PCR, todavia, resultados de coagulase através das técnicas em tubo e "coagulase slide test" foram variáveis. Após a amplificação do gen de coagulase através da técnica de PCR utilizando iniciadores específicos para o referido gen, fragmentos com diferentes pesos moleculares foram vistos através de análise em gel de agarose, sugerindo a ocorrência de polimorfismo genético. O estudo também sugere a ocorrência de diferentes cepas da bactéria atuando nos rebanhos leiteiros causando mastite bovina.
Detecção da toxina-1 da síndrome do choque tóxico em amostras de Staphylococcus aureus isoladas de mastite bovina Detection of toxic shock syndrome toxin by Staphylococcus aureus strains isolated from bovine mastitis
Full Text Available Este trabalho teve por objetivo caracterizar a produção da toxina da síndrome do choque tóxico (TSST-1 e de enterotoxinas estafilocócicas (SE A, B, C e D em 127 amostras de S. aureus, isoladas de amostras de leite proveniente de vacas com mastite no Estado de Minas Gerais, entre 1994 e 1997. A verificação da produção de toxinas foi feita pela técnica de sensibilidade ótima em placa. Das 127 amostras testadas, 60 (47% eram produtoras de TSST-1 e 54 (43% produtoras de SE, 38 amostras produziram SED (30%, 24 SEB (19%, 8 SEC (6% e 4 SEA (3%. Estes resultados trazem preocupações quanto à saúde pública pela alta prevalência de amostras de S. aureus produtoras de TSST-1 e de enterotoxinas em isolamentos a partir de leite de vacas com mastite.A total of 127 strains of Staphylococcus aureus were examined for the production of toxic shock syndrome toxin (TSST-1 and staphylococcal enterotoxins (SE A, B, C and D. The strains were isolated from milk samples from cows with mastitis in dairy herds of Minas Gerais State, Brazil, from 1994 to 1997. The toxins were detected using the optimum-sensitivity plate method. Of 127 isolates, 60 (47% produced TSST-1 and 54 (43% produced SE, 38 (30% produced SED, 24 (19% SEB, 8 (6% SEC and 4 (3% enterotoxin A..
Kareivienė, Violeta; Pavilonis, Alvydas; Sinkutė, Gintarė; Liegiūtė, Sigutė; Gailienė, Greta
Objective. The aim of this study was to identify the phage groups of Staphylococcus aureus strains, their prevalence, and resistance of different phage groups to antibiotics. Materials and methods. A total of 294 Staphylococcus aureus strains in Kaunas hospitals were obtained; they were phage typed and their resistance to antibiotics was determined. We used the method of routine dilution to test 17 antibiotics against the isolates. Susceptibility of Staphylococcus aureus to studied antibio...
Atividade antimicrobiana do extrato de Anacardium occidentale Linn. em amostras multiresistentes de Staphylococcus aureus Antimicrobial activity of the hydroalcoholic extract of Anacardium occidentale Linn. against multi-drug resistant strains of Staphylococcus aureus
Jackeline G. da Silva
Full Text Available Plantas medicinais com propriedades terapêuticas são de grande relevância em todo o mundo, principalmente em países em desenvolvimento. A planta Anacardium occidentale Linn. é largamente usada na medicina tradicional na nossa região, como antidiarréico, para amigdalite, bronquites, artrites, e antiiflamatório. No presente estudo avaliou-se a ação antimicrobiana do extrato hidroalcóolico da casca do caule do cajueiro frente a amostras de Staphylococcus aureus resistentes e sensíveis à meticilina, obtidas a partir de pacientes internados do Hospital Universitário/Universidade Federal da Paraíba. A atividade antimicrobiana foi determinada pelo método de difusão em meio sólido para a determinação da Concentração Inibitória Mínima do extrato, e foi observada no total de 30 amostras, pela presença ou não do halo de inibição. Todas as amostras ensaiadas mostraram-se sensíveis à ação do extrato do cajueiro, com diâmetros dos halos de inibição variando de 10 a 20 mm, demonstrando grande eficácia do cajueiro. Assim, o uso desta planta na nossa região pode inferir uma alternativa terapêutica eficiente e de baixo custo, contra infecções bacterianas causadas por Staphylococcus aureus.Medicinal plants with therapeutical properties are of great significance in the whole world, especially in developing countries. Anacardium occidentale Linn. is a plant widely used in the traditional medicine in our region against diarrhea, tonsillitis, bronchitis, arthritis, and inflammation. In this paper, the antimicrobial activity of the hydroalcoholic extract of the cashew tree stem was evaluated against samples of meticillin-resistant and meticillin-sensible Staphylococcus aureus, attained from patients interned at Hospital Universitário/Universidade Federal da Paraíba. The antimicrobial activity was determined by the diffusion method in solid milieu to determine the Minimum Inhibitory Concentration (MIC of the extract, and it was
Tesařová, Marie; Horká, Marie; Moravcová, Dana; Svojanovská, Lenka; Mlynariková, K.; Růžička, F.
Roč. 72, č. 3 (2016), s. 315-320. ISSN 0343-8651 R&D Projects: GA MV VG20112015021 Institutional support: RVO:68081715 Keywords : methicillin-resistant and methicillin-sensitive Staphylococcus aureus * sodium dodecylsulphate polyacrylamide gel electrophoresis * gel isoelectric focusing * precipitated proteins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.423, year: 2014 http://hdl.handle.net/11104/0251069
Spreading of genes encoding enterotoxins, haemolysins, adhesin and biofilm among methicillin resistant Staphylococcus aureus strains with staphylococcal cassette chromosome mec type IIIA isolated from burn patients.
Motallebi, Mitra; Jabalameli, Fereshteh; Asadollahi, Kheirollah; Taherikalani, Morovat; Emaneini, Mohammad
The emergence of antibiotic-resistant Staphylococcus aureus in particular methicillin-resistant S. aureus (MRSA) is an important concern in burn medical centers either in Iran or worldwide. A total of 128 S. aureus isolates were collected from wound infection of burn patients during June 2013 to June 2014. Multiplex-polymerase chain reaction (MPCR) assay was performed for the characterization of the staphylococcal cassette chromosome mec (SCCmec). Genes encoding virulence factors and biofilm were targeted by PCR. Of 128 S. aureus isolates, 77 (60.1%) isolates were MRSA. Fifty four (70.1%) isolates were identified as SCCmec type IIIA. The most frequently detected toxin genes among MRSA isolates with SCCmec type IIIA were sea (64.1%) and hla (51.8%). The rate of coexistence of sea with hla and sea with hla and hlb was 37% and12.9%, respectively. The sec, eta, tst, pvl, hla and hlb genes were not detected in any of the MRSA isolates. The most prevalent genes encoding biofilm was eno, found in 61.1% of isolates, followed by fib and icaA found in 48.1% and 38.8% of the isolates, respectively. The rate of coexistence of fib + eno + icaA + icaD and fib + eno was 20.3% and 9.2%, respectively. The ebps gene was not detected in any of the isolates. In conclusion, our study indicated that the sea, hla, fib and icaA were most frequent genes encoding virulence factors among MRSA with SCCmec type IIIA isolated from burn wound infection. Moreover, the results of this study shows that the rate of coexistence of genes encoding different virulence factor were high. PMID:27238459
Budri, P E; Silva, N C C; Bonsaglia, E C R; Fernandes Júnior, A; Araújo Júnior, J P; Doyama, J T; Gonçalves, J L; Santos, M V; Fitzgerald-Hughes, D; Rall, V L M
Bovine mastitis is an inflammation of the mammary glands of cows and causes significant economic losses in dairy cattle. Staphylococcus aureus is one of the microorganisms most commonly isolated. Novel agents are required in agricultural industries to prevent the development of mastitis. The production of biofilm by Staph. aureus facilitates the adhesion of bacteria to solid surfaces and contributes to the transmission and maintenance of these bacteria. The effect of the essential oils of Syzygium aromaticum (clove; EOSA) and Cinnamomum zeylanicum (cinnamon; EOCZ) and their major components, eugenol and cinnamaldehyde, on Staph. aureus biofilm formation on different surfaces was investigated. The results showed a significant inhibition of biofilm production by EOSA on polystyrene and stainless steel surfaces (69.4 and 63.6%, respectively). However, its major component, eugenol, was less effective on polystyrene and stainless steel (52.8 and 19.6%, respectively). Both EOCZ and its major component, cinnamaldehyde, significantly reduced biofilm formation on polystyrene (74.7 and 69.6%, respectively) and on stainless steel surfaces (45.3 and 44.9%, respectively). These findings suggest that EOSA, EOCZ, and cinnamaldehyde may be considered for applications such as sanitization in the food industry. PMID:26142866
苏洋; 蒲万霞; 陈智华; 邓海平
[目的]了解内蒙古地区奶牛乳房炎金黄色葡萄球菌耐药性和耐甲氧西林金黄色葡萄球菌(MRSA)感染的情况,为奶牛乳房炎的防治提供理论依据.[方法]采用K-B纸片扩散法,检测分离自内蒙古地区38株金黄色葡萄球菌对17种药物的敏感性,同时用琼脂稀释法检测苯唑西林、万古霉素对金黄色葡萄球菌的最小抑菌浓度(MIC)；再用头孢西丁、苯唑西林纸片扩散法、苯唑西林盐琼脂筛选法和PCR方法扩增mecA耐药基因对分离菌株进行全面MRSA检测.[结果]分离菌株对每种抗生素都有不同程度抗性,对氨苄西林、头孢拉丁、青霉素、复方新诺明、新生霉素和链霉素的耐药率都高于45％,而对氧氟沙星、丁胺卡那霉素、万古霉素、环丙沙星、庆大霉素和头孢唑林的敏感性高于90％,2株细菌的万古霉素MIC≥16 μg.mL-1；其中8株细菌的苯唑西林MIC≥8μg·mL-1,而其它菌株的苯唑西林MIC≤2μg·mL-1,分离菌株多重耐药情况严重,耐受3种及3种以上药物的菌株占84.21％,其中4株细菌能同时耐受9种不同抗菌药物；16 (42.11％)株细菌被检测携带mecA耐药基因,而仅有其中7株的苯唑西林MIC≥4 μg·mL-1;头孢西丁、苯唑西林纸片扩散法和苯唑西林盐琼脂筛选法分别检出7株、10株和7株表型为MRSA的菌株.[结论]分离菌株的耐药性和多重耐药现象较为严重,被调查地区奶牛场中已经存在MRSA和OS-MRSA感染情况,且感染率高.%[Objective] The aim of the study is to investigate the antimicrobial resistance of S. aureus (Science) and to detect the presence of methicillin-resistant S. aureus (MRSA) among S. aureus strains isolated from bovine mastitis in Inner Mongolia, and to provide credible theory evidence for prevention and treatment of bovine mastitis. [Method] K-B.disk diffusion method was used to test drug sensitivity of 38 total strains of S.aureus to 17 commonly used antibiotics
Efficiency of vanilla, patchouli and ylang ylang essential oils stabilized by iron oxide@C14 nanostructures against bacterial adherence and biofilms formed by Staphylococcus aureus and Klebsiella pneumoniae clinical strains.
Bilcu, Maxim; Grumezescu, Alexandru Mihai; Oprea, Alexandra Elena; Popescu, Roxana Cristina; Mogoșanu, George Dan; Hristu, Radu; Stanciu, George A; Mihailescu, Dan Florin; Lazar, Veronica; Bezirtzoglou, Eugenia; Chifiriuc, Mariana Carmen
Biofilms formed by bacterial cells are associated with drastically enhanced resistance against most antimicrobial agents, contributing to the persistence and chronicization of the microbial infections and to therapy failure. The purpose of this study was to combine the unique properties of magnetic nanoparticles with the antimicrobial activity of three essential oils to obtain novel nanobiosystems that could be used as coatings for catheter pieces with an improved resistance to Staphylococcus aureus and Klebsiella pneumoniae clinical strains adherence and biofilm development. The essential oils of ylang ylang, patchouli and vanilla were stabilized by the interaction with iron oxide@C14 nanoparticles to be further used as coating agents for medical surfaces. Iron oxide@C14 was prepared by co-precipitation of Fe+2 and Fe+3 and myristic acid (C14) in basic medium. Vanilla essential oil loaded nanoparticles pelliculised on the catheter samples surface strongly inhibited both the initial adherence of S. aureus cells (quantified at 24 h) and the development of the mature biofilm quantified at 48 h. Patchouli and ylang-ylang essential oils inhibited mostly the initial adherence phase of S. aureus biofilm development. In the case of K. pneumoniae, all tested nanosystems exhibited similar efficiency, being active mostly against the adherence K. pneumoniae cells to the tested catheter specimens. The new nanobiosystems based on vanilla, patchouli and ylang-ylang essential oils could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with anti-adherence and anti-biofilm properties. PMID:25375335
Efficiency of Vanilla, Patchouli and Ylang Ylang Essential Oils Stabilized by Iron Oxide@C14 Nanostructures against Bacterial Adherence and Biofilms Formed by Staphylococcus aureus and Klebsiella pneumoniae Clinical Strains
Full Text Available Biofilms formed by bacterial cells are associated with drastically enhanced resistance against most antimicrobial agents, contributing to the persistence and chronicization of the microbial infections and to therapy failure. The purpose of this study was to combine the unique properties of magnetic nanoparticles with the antimicrobial activity of three essential oils to obtain novel nanobiosystems that could be used as coatings for catheter pieces with an improved resistance to Staphylococcus aureus and Klebsiella pneumoniae clinical strains adherence and biofilm development. The essential oils of ylang ylang, patchouli and vanilla were stabilized by the interaction with iron oxide@C14 nanoparticles to be further used as coating agents for medical surfaces. Iron oxide@C14 was prepared by co-precipitation of Fe+2 and Fe+3 and myristic acid (C14 in basic medium. Vanilla essential oil loaded nanoparticles pelliculised on the catheter samples surface strongly inhibited both the initial adherence of S. aureus cells (quantified at 24 h and the development of the mature biofilm quantified at 48 h. Patchouli and ylang-ylang essential oils inhibited mostly the initial adherence phase of S. aureus biofilm development. In the case of K. pneumoniae, all tested nanosystems exhibited similar efficiency, being active mostly against the adherence K. pneumoniae cells to the tested catheter specimens. The new nanobiosystems based on vanilla, patchouli and ylang-ylang essential oils could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with anti-adherence and anti-biofilm properties.
Intra- and extracellular activities of dicloxacillin and linezolid against a clinical Staphylococcus aureus strain with a small-colony-variant phenotype in an in vitro model of THP-1 macrophages and an in vivo mouse peritonitis model.
Sandberg, Anne; Lemaire, Sandrine; Van Bambeke, Françoise; Tulkens, Paul M; Hughes, Diarmaid; von Eiff, Christof; Frimodt-Møller, Niels
The small-colony-variant (SCV) phenotype of Staphylococcus aureus has been associated with difficult-to-treat infections, reduced antimicrobial susceptibility, and intracellular persistence. This study represents a detailed intra- and extracellular investigation of a clinical wild-type (WT) S. aureus strain and its counterpart with an SCV phenotype both in vitro and in vivo, using the THP-1 cell line model and the mouse peritonitis model, respectively. Bacteria of both phenotypes infected the mouse peritoneum intra- and extracellularly. The SCV phenotype was less virulent and showed distinct bacterial clearance, a reduced multiplication capacity, and a reduced internalization ability. However, some of the SCV-infected mice were still culture positive up to 96 h postinfection, and bacteria of this phenotype could spread to the mouse kidney and furthermore revert to the more virulent WT phenotype in both the mouse peritoneum and kidney. The SCV phenotype is therefore, despite reduced virulence, an important player in S. aureus pathogenesis. In the THP-1 cell line model, both dicloxacillin (DCX) and linezolid (LZD) reduced the intracellular inocula of bacteria of both phenotypes by approximately 1 to 1.5 log(10) in vitro, while DCX was considerably more effective against extracellular bacteria. In the mouse peritonitis model, DCX and LZD were also able to control both intra- and extracellular infections caused by either phenotype. Treatment with a single dose of DCX and LZD was, however, insufficient to clear the SCVs in the kidneys, and the risk of recurrent infection remained. This stresses the importance of an optimal dosing of the antibiotic when SCVs are present. PMID:21282430
Hernandez, David; Seidl, Kati; Corvaglia, Anna-Rita; Bayer, Arnold S.; Xiong, Yan Q.; Francois, Patrice
Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia (positive blood cultures after ≥7 days) represents a challenging subset of invasive MRSA infections. The comparison of genome sequences of persistent (300-169) and resolving (301-188) MRSA bacteremia isolates with similar genetic background (sequence type 45 [ST45]) will help us to better understand underlying mechanisms of persistent MRSA bacteremia.
Sinergismo entre óleos essenciais e drogas antimicrobianas sobre linhagens de Staphylococcus aureus e Escherichia coli isoladas de casos clínicos humanos Synergism between essential oils and antimicrobial drugs against Staphylooccus aureus and Escherichia coli strains from human infections
Juliana A. A. Zago
Full Text Available Estudos com plantas e utilização em terapias combinatórias têm sido estimulados. Verificou-se as possíveis interações entre óleos essenciais de plantas [canela (Cinnamomum zeylanicum Blume Lauraceae, capim-cidreira (Cymbopogon citratus (DC. Stapf, Poaceae, hortelã-pimenta (Mentha piperita L. Lamiaceae, gengibre (Zingiber officinale Roscoe Zingiberaceae, cravo-da-índia (Caryophillus aromaticus L. Myrtaceae e alecrim (Rosmarinus officinalis L. Lamiaceae] combinados a oito drogas antimicrobianas frente a doze linhagens de Staphylococcus aureus e doze de Escherichia coli isoladas de humanos. Após determinação da Concentração Inibitória Mínima (CIM para os óleos pelo método da diluição foram realizados ensaios para verificação de sinergismo entre os óleos essenciais e os antimicrobianos pela metodologia de Kirby & Bauer. S. aureus foi mais suscetível às interações óleos e drogas, tendo o óleo de capim cidreira apresentado sinergismo com as oito drogas testadas, seguido pelo óleo de hortelã com sete drogas. Nos ensaios com E. coli, houve sinergismo apenas para os óleos de alecrim (três drogas e capim-cidreira (duas drogas. Não ocorreram casos de antagonismo e os resultados de sinergismo foram influenciados pelos microrganismos estudados.The studies with plants and combinatory therapy have been stimulated. The interactions between cinnamon (Cinnamomun zeylanicum Blume Lauraceae, lemon grass (Cymbopogon citratus (DC. Stapf, Poaceae, mint (Mentha piperita L. Lamiaceae, ginger (Zingiber officinale Roscoe Zingiberaceae, clove (Caryophillus aromaticus L. Myrtaceae and rosemary (Rosmarinus officinalis L. Lamiaceae and eight antimicrobial drug was carried. It was made against twelve S. aureus and twelve E.coli strains isolated from human specimens. After minimal inhibitory concentration (MIC values determination of essential oils by dilution agar method, the synergism assays were performed by Kirby and Bauer method. The S
Daum, T E; Schaberg, D R; Terpenning, M S; Sottile, W S; Kauffman, C A
We demonstrated the marked emergence of resistance to ciprofloxacin among Staphylococcus arueus strains isolated at the Ann Arbor Veterans Administration Medical Center. All S. aureus isolates tested from 1984 to 1985 were susceptible, whereas 55.1% of methicillin-resistant and 2.5% of methicillin-susceptible strains from 1989 had high-level resistance to ciprofloxacin.
Full Text Available In China, fosfomycin alone or in combination with other antibiotics is commonly used in the treatment of infections caused by Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA. Although fosfomycin-resistant S. aureus strains have continued to emerge and increase, the research on them is rare. In order to determine the prevalence and mechanisms of fosfomycin resistance in MRSA clinical isolates, a total of 96 non-duplicate MRSA isolates were collected from blood and cerebrospinal fluid samples at Huashan Hospital in Shanghai, China between 2004 and 2014. Antimicrobial susceptibility testing was performed by agar dilution. Meanwhile, the fosfomycin-resistance-related genes, fosB, murA, glpT, and uhpT, were amplified by PCR and subjected to sequencing analysis. Multilocus sequence typing (MLST was conducted to assess strain types. The minimum inhibitory concentration (MIC of fosfomycin for the 96 MRSA strains ranged from 1.0 to >1,024 mg/L, and approximately 70% (67/96 of the isolates were resistant to fosfomycin (MIC ≥ 64.0 mg/L. Nine isolates with MICs ≥ 128 mg/L carried fosB gene. Twenty-five distinct mutations were detected in the murA (7, glpT (10, and uhpT (8 genes. While five of the murA mutations and five of the glpT mutations were observed only in fosfomycin-sensitive isolates and one of the murA mutation was found both in fosfomycin-resistant and fosfomycin-sensitive isolates, the remaining 14 mutations (1 murA, 5 glpT, and all uhpT mutations were present only in fosfomycin-resistant isolates. MLST analysis demonstrated that the majority (46/67 of the glpT and/or uhpT mutants belong to ST5, the predominant sequence type among the fosfomycin-resistant MRSA isolates. In conclusion, there is a high rate of fosfomycin resistance in MRSA strains. The mutations in the murA, glpT, and uhpT genes are common in fosfomycin-resistant MRSA strains, and may play a greater role in the development of fosfomycin
Full Text Available The present study was designed to assess and compare three different formulations of the new Onderstepoort infectious coryza (IC quadrivalent vaccine, which contain an NAD-independent strain of Avibacterium paragallinarum (previously known as Haemophilus paragallinarum, and a commercial IC vaccine, not containing an NAD-independent strain, for their safety and ability to protect chickens of varying ages against virulent challenges with four different serovars of A. paragallinarum, including the NAD-independent strain of the C-3 serovar. Four groups of 140 chickens each were vaccinated at the age of 17 weeks and revaccinated at the age of 19 weeks with each of the four vaccine formulations. A similar sized group of non-vaccinated chickens was used as control. Two rounds of challenge were conducted: a group of chicken in each vaccination group was challenged between 31 and 35 weeks of age, while another group was challenged between 51 and 55 weeks of age. The ''in-contact'' challenge model was used in this experiment. For each vaccination group, the four challenge strains representing four local serovars were used in each challenge round. The efficacy of the vaccines was compared based on overall protection levels obtained and the duration of protection. The safety of the different vaccines was determined by the severity of post-vaccination reactions. The need for the incorporation of the NAD-independent strain in the vaccine was evidenced by the low protection level against NAD-independent challenge recorded in the group of birds vaccinated with the commercial vaccine. The results obtained confirmed not only the variation in virulence of different South African serovars, with serovar C-3 being the most virulent and serovar B having almost no virulence but also the age related increase in susceptibility. The importance of a suitable formulation of the vaccine is discussed.
Le Maréchal Caroline; Jardin Julien; Jan Gwenaël; Even Sergine; Pulido Coralie; Guibert Jean-Michel; Hernandez David; François Patrice; Schrenzel Jacques; Demon Dieter; Meyer Evelyne; Berkova Nadia; Thiéry Richard; Vautor Eric; Le Loir Yves
Abstract Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11) or subclinical (strain O46) mastitis. Strains induced drastically distinct clinical symptoms when tested in ew...
Steidl, Rebecca; Pearson, Stacy; Stephenson, Robert E.; Ledala, Nagender; Sitthisak, Sutthirat; Wilkinson, Brian J; Jayaswal, Radheshyam K.
lacZ fusion strains were constructed using the promoters of five cell wall stress stimulon genes: pbp2, tcaA, vraSR, sgtB, and lytR. All fusion strains were induced only in the presence of cell wall-active antibiotics, suggesting the potential of these strains for use in high-throughput screening for new cell wall-active agents.
Holmes, Mark A.; Harrison, Ewan M.; Fisher, Elizabeth A.; Graham, Elizabeth M.; Parkhill, Julian; Foster, Geoffrey; Paterson, Gavin K.
In addition to being an important human pathogen, Staphylococcus aureus is able to cause a variety of infections in numerous other host species. While the S. aureus strains causing infection in several of these hosts have been well characterised, this is not the case for companion rabbits (Oryctolagus cuniculus), where little data are available on S. aureus strains from this host. To address this deficiency we have performed antimicrobial susceptibility testing and genome sequencing on a collection of S. aureus isolates from companion rabbits. The findings show a diverse S. aureus population is able to cause infection in this host, and while antimicrobial resistance was uncommon, the isolates possess a range of known and putative virulence factors consistent with a diverse clinical presentation in companion rabbits including severe abscesses. We additionally show that companion rabbit isolates carry polymorphisms within dltB as described as underlying host-adaption of S. aureus to farmed rabbits. The availability of S. aureus genome sequences from companion rabbits provides an important aid to understanding the pathogenesis of disease in this host and in the clinical management and surveillance of these infections. PMID:26963381
苏洋; 蒲万霞; 邓海平; 李春慧; 梁红雁; 陈智华
本研究旨在了解甘肃地区奶牛乳房炎金黄色葡萄球菌的耐药性和耐甲氧西林金黄色葡萄球菌的感染情况,为奶牛乳房炎的防制提供理论依据.采用KB纸片扩散法,检测17株金黄色葡萄球菌对8种不同抗菌药物的敏感性；再用琼脂稀释法检测了苯唑西林、万古霉素对金黄色葡萄球菌的最小抑菌浓度(MICs)；头孢西丁纸片扩散法和PCR扩增特异性mecA耐药基因对所有受试菌株进行全面的耐甲氧西林金黄色葡萄球菌检测.结果表明,菌株对青霉素、磺胺异恶唑具有较强抗性,而对环丙沙星、头孢唑啉、万古霉素和苯唑西林全敏感；头孢西丁纸片扩散法未能检测出表型为MRSA的阳性菌株,而PCR方法却检测出8株mecA基因阳性菌株,且这些菌株的苯唑西林MIC均小于2μg/mL.菌株的耐药情况较严重,对甲氧西林敏感而携带mecA基因的菌株高频存在于被调查地区的奶牛场中.%The aim of present study was to investigate the antimicrobial resistance, and the prevalence of methicillin-resistant Staphylococcus aureus (S. aureus) isolated from bovine mastitis in Gansu province, to provide credible theory evidence for prevention and treatment on bovine mastitis. Eight commonly used antimicrobial agents were used for determining antimicrobial susceptibility of 17 total S. aureus strains by disk diffusion method. Agar screen method was used for determining the oxacil-lin and vancomycin minimum inhibitory concentration value as well. Disk diffusion method using the cephamycin antibiotics ce-foxitin and detection of mecA gene by PCR assay were performed to detect the presence of MRSA. Most of strains showed a high resistance for penicillin and sulfafurazole, yet keeping complete sensitivity for ciprofloxacin, cefazolin, vancomycin and ox-acillin. None MRS A isolate was identified by the phenotypic detection method, but eight MRSA isolates with the MIC of oxac-illin lower than 2 μg/mL were
Objective: To detect genes for enterotoxins, exfoliative and toxic shock syndrome toxins in Staphylococcus aureus (S. aureus) strains isolated from clinical specimens. Study Design: Cross-sectional observational study. Place and Duration of Study: Department of Molecular Genetics, Dr. Ziauddin Hospital, Karachi, from January to December 2010. Methodology: Two hundred and ninety eight S. aureus clinical isolates were obtained from various clinical samples received at Dr. Ziauddin Hospital, Karachi. Out of these, 115 were detected as methicillin resistant (MRSA) by cefoxitin disk diffusion test showing a prevalence rate of 38.6%. Detection of individual toxin genes was performed by Polymerase Chain Reaction (PCR) by using only one primer pair for each tube. Uniplex primers were preferred as multiplex primers are longer in base pairs and have the potential for cross reaction due to non-specific binding and increase in optimization time. Results: The possession of a single gene or more than a single gene in MRSA isolates was found in 61.73% of clinical samples; the highest number was found in pus swab, followed by sputum, blood, urethral swab, and urine. The prevalence of toxin genes was higher in MRSA as compared to methicillin sensitive (MSSA) isolates (19.12%). Conclusion: PCR detects strains possessing toxin genes independent of their expression. The possession of genes for super-antigens seems to be a frequent and habitual trait of S. aureus more so in MRSA. (author)
O'Neill, Eoghan; Pozzi, Clarissa; Houston, Patrick; Humphreys, Hilary; Robinson, D. Ashley; Loughman, Anthony; Foster, Timothy J.; O'Gara, James P.
Device-associated infections involving biofilm remain a persistent clinical problem. We recently reported that four methicillin-resistant Staphylococcus aureus (MRSA) strains formed biofilm independently of the icaADBC-encoded exopolysaccharide. Here, we report that MRSA biofilm development was promoted under mildly acidic growth conditions triggered by the addition of glucose to the growth medium. Loss of sortase, which anchors LPXTG-containing proteins to peptidoglycan, reduced the MRSA bio...
Janssen, D A; Zarins, L T; Schaberg, D R; Bradley, S. F.; Terpenning, M S; Kauffman, C A
Fourteen mupirocin-resistant Staphylococcus aureus strains were isolated over 18 months; 12 exhibited low-level resistance, while two showed high-level resistance. Highly mupirocin-resistant strains contained a large plasmid which transferred mupirocin resistance to other S. aureus strains and to Staphylococcus epidermidis. This plasmid and pAM899-1, a self-transferable gentamicin resistance plasmid, have molecular and biologic similarities.
Harter, L. V.; Hruska, K. A.; Duncan, R. L.
Exposure of osteosarcoma cell lines to chronic intermittent strain increases the activity of mechano-sensitive cation (SA-cat) channels. The impact of mechano-transduction on osteoblast function has not been well studied. We analyzed the expression and production of bone matrix proteins in human osteoblast-like osteosarcoma cells, OHS-4, in response to chronic intermittent mechanical strain. The OHS-4 cells exhibit type I collagen production, 1,25-Dihydroxyvitamin D-inducible osteocalcin, and mineralization of the extracellular matrix. The matrix protein message level was determined from total RNA isolated from cells exposed to 1-4 days of chronic intermittent strain. Northern analysis for type I collagen indicated that strain increased collagen message after 48 h. Immunofluorescent labeling of type I collagen demonstrated that secretion was also enhanced with mechanical strain. Osteopontin message levels were increased several-fold by the application of mechanical load in the absence of vitamin D, and the two stimuli together produced an additive effect. Osteocalcin secretion was also increased with cyclic strain. Osteocalcin levels were not detectable in vitamin D-untreated control cells. However, after 4 days of induced load, significant levels of osteocalcin were observed in the medium. With vitamin D present, osteocalcin levels were 4 times higher in the medium of strained cells compared to nonstrained controls. We conclude that mechanical strain of osteoblast-like cells is sufficient to increase the transcription and secretion of matrix proteins via mechano-transduction without hormonal induction.
邓建军; 万朝敏; 母得志; 范娟; 徐爱丽; 肖国光; 舒敏
目的 调查成都地区儿童金黄色葡萄球菌定植/感染分离株的流行病学特征.方法 2004年1月 - 2009年4月,以成都市健康儿童、门诊呼吸道感染患儿和金黄色葡萄球菌感染住院患儿为研究对象,采集鼻拭子或感染部位标本进行培养,并对分离的金黄色葡萄球菌进行药敏实验,应用PCR方法检测菌株的PVL毒力基因和mecA耐药基因,对菌株进行多位点序列分析(MLST).结果 培养分离金黄色葡萄球菌定植株174株、感染株51株.门诊呼吸道感染患儿金葡菌的多重耐药率分别为,定植株59.3%,感染株52.9%;PVL基因阳性率分别为,定植株55.6%(15/27),感染株80.4%(41/51);mecA耐药基因阳性率分别为,定植株11.1%(3/27),感染株62.7%(32/51).对健康儿童定植株以及感染株进行MLST分析,共发现33个ST类型,定植株以ST121、ST59和ST398为主,感染株以ST121、ST88和ST398为主;这些菌株属于15个克隆类型,以CC121、CC59和CC398为主.结论 成都地区儿童金黄色葡萄球菌定植和感染分离株具有较高的PVL毒力基因和mecA耐药基因携带率,具有明显不同于其他地区的独特的遗传背景.%bstract: Objective To evaluate antibiotic resistance profiling and molecular characteristics of Staphylococcus aureus strains in healthy or infected Children in Chengdu. Methods From January, 2004 to April, 2009, we isolated Staphylococcus aureus from hospitalized pediatric patients with S. Aureus infection, outpatients with respiratory tract infections and healthy children in Chengdu and the antibiotic resistance was tested. PCR was used to assess presence/ absence of mecA and PVL genes, and multilocus sequence typing (MLST) were performed. Results One hundred and seventy-four children carried S. Aureus, and 51 children were infected with S. Aureus. Sixteen isolates from patients with respiratory tract infections (59.2%) , and twenty seven isolates from S. Aureus infected patients ( 52.9% ) were multi
Weston, David J; Pelletier, Dale A; Morrell-Falvey, Jennifer L; Tschaplinski, Timothy J; Jawdy, Sara S; Lu, Tse-Yuan; Allen, Sara M; Melton, Sarah J; Martin, Madhavi Z; Schadt, Christopher W; Karve, Abhijit A; Chen, Jin-Gui; Yang, Xiaohan; Doktycz, Mitchel J; Tuskan, Gerald A
Colonization of plants by nonpathogenic Pseudomonas fluorescens strains can confer enhanced defense capacity against a broad spectrum of pathogens. Few studies, however, have linked defense pathway regulation to primary metabolism and physiology. In this study, physiological data, metabolites, and transcript profiles are integrated to elucidate how molecular networks initiated at the root-microbe interface influence shoot metabolism and whole-plant performance. Experiments with Arabidopsis thaliana were performed using the newly identified P. fluorescens GM30 or P. fluorescens Pf-5 strains. Co-expression networks indicated that Pf-5 and GM30 induced a subnetwork specific to roots enriched for genes participating in RNA regulation, protein degradation, and hormonal metabolism. In contrast, only GM30 induced a subnetwork enriched for calcium signaling, sugar and nutrient signaling, and auxin metabolism, suggesting strain dependence in network architecture. In addition, one subnetwork present in shoots was enriched for genes in secondary metabolism, photosynthetic light reactions, and hormone metabolism. Metabolite analysis indicated that this network initiated changes in carbohydrate and amino acid metabolism. Consistent with this, we observed strain-specific responses in tryptophan and phenylalanine abundance. Both strains reduced host plant carbon gain and fitness, yet provided a clear fitness benefit when plants were challenged with the pathogen P. syringae DC3000. PMID:22375709
Full Text Available Abstract Background The first step in invasive disease caused by the normally commensal bacteria Streptococcus pneumoniae, Staphylococcus aureus and Haemophilus influenzae is their colonization of the nasal passages. For any population to colonize a new habitat it is necessary for it to be able to compete with the existing organisms and evade predation. In the case of colonization of these species the competition is between strains of the same and different species of bacteria and the predation is mediated by the host's immune response. Here, we use a neonatal rat model to explore these elements of the ecology of nasal colonization by these occasionally invasive bacteria. Results When neonatal rats are colonized by any one of these species the density of bacteria in the nasal passage rapidly reaches a steady-state density that is species-specific but independent of inoculum size. When novel populations of H. influenzae and S. pneumoniae are introduced into the nasal passages of neonatal rats with established populations of the same species, residents and invaders coexisted. However, this was not the case for S. aureus - the established population inhibited invasion of new S. aureus populations. In mixed-species introductions, S. aureus or S. pneumoniae facilitated the invasion of another H. influenzae population; for other pairs the interaction was antagonistic and immune-mediated. For example, under some conditions H. influenzae promoted an immune response which limited the invasion of S. pneumoniae. Conclusions Nasal colonization is a dynamic process with turnover of new strains and new species. These results suggest that multiple strains of either H. influenzae or S. pneumoniae can coexist; in contrast, S. aureus strains require a host to have no other S. aureus present to colonize. Levels of colonization (and hence the possible risk of invasive disease by H. influenzae are increased in hosts pre-colonized with either S. aureus or S
Claassen-Weitz, Shantelle; Shittu, Adebayo O.; Ngwarai, Michelle R.; Thabane, Lehana; Nicol, Mark P.; Kaba, Mamadou
Background and rationale: Staphylococcus aureus fecal carriage has been identified as a potential source for nosocomial transmission and a risk factor for disease development. This systematic review determined the overall S. aureus [including methicillin susceptible and resistant S. aureus (MSSA and MRSA)] fecal carriage rates within the community and healthcare settings. Methodology: Peer-reviewed articles indexed in Medline, Scopus, Academic Search Premier, Africa-Wide Information, CINAHL, and Web of Science were identified using applicable and controlled vocabulary through to 11 November 2015. Eligible studies were ascertained by three independent reviewers. Random-effects meta-analyses of proportions were performed to determine S. aureus, MSSA and MRSA fecal carriage rates reported by eligible studies. Results: Twenty six studies were included in this review. The pooled estimates for S. aureus, MSSA and MRSA fecal carriage were 26% (95% confidence interval (CI): 16.8–36.3%), 86% (95% confidence interval (CI): 65.9–97.9%) and 10% (95% CI: 0.7–27.0%), respectively. Fecal S. aureus carriage rates increased on average from 10 to 65% during the first 8 weeks of life, followed by an average carriage rate of 64% at 6 months and 46% at 1 year of life. Genotyping techniques were employed mainly in studies conducted in developed countries and comprised largely of gel-based techniques. Six studies reported on the role of S. aureus fecal strains in diarrhea (n = 2) and the risk for acquiring infections (n = 4). Eight of the 26 studies included in this review performed antibiotic susceptibility testing of S. aureus fecal isolates. Conclusion: This study provides evidence that screening for S. aureus fecal carriage, at least in populations at high risk, could be an effective measure for the prevention of S. aureus transmission and infection in the healthcare and community setting. More well-structured studies need to be conducted and sequence-based genotyping
Full Text Available Background and rationale: Staphylococcus aureus faecal carriage has been identified as a potential source for nosocomial transmission and a risk factor for disease development. This systematic review determined the overall S. aureus (including methicillin susceptible and resistant S. aureus (MSSA and MRSA faecal carriage rates within the community and healthcare settings.Methodology: Peer-reviewed articles indexed in Medline, Scopus, Academic Search Premier, Africa-Wide Information, CINAHL, and Web of Science were identified using applicable and controlled vocabulary through to 11 November 2015. Eligible studies were ascertained by three independent reviewers. Random-effects meta-analyses of proportions were performed to determine S. aureus, MSSA and MRSA faecal carriage rates reported by eligible studies.Results: Twenty six studies were included in this review. The pooled estimates for S. aureus, MSSA and MRSA faecal carriage were 26 % (95 % confidence interval (CI: 16.8 % - 36.3 %, 86 % (95 % confidence interval (CI: 65.9 % - 97.9 % and 10 % (95 % CI: 0.7 % - 27.0 %, respectively. Faecal S. aureus carriage rates increased on average from 10 % to 65 % during the first eight weeks of life, followed by an average carriage rate of 64 % at six months and 46 % at one year of life. Genotyping techniques were employed mainly in studies conducted in developed countries and comprised largely of gel-based techniques. Six studies reported on the role of S. aureus faecal strains in diarrhoea (n = 2 and the risk for acquiring infections (n = 4. Eight of the 26 studies included in this review performed antibiotic susceptibility testing of S. aureus faecal isolates.Conclusion: This study provides evidence that screening for S. aureus faecal carriage, at least in populations at high risk, could be an effective measure for the prevention of S. aureus transmission and infection in the healthcare and community setting. More well-structured studies need to be
Staphylococcus aureus and Pregnancy In every pregnancy, a woman starts out with a 3-5% chance of ... risk. This sheet talks about whether exposure to staphylococcus aureus may increase the risk for birth defects ...
Full Text Available This study compared the variability of 3D echo derived circumferential and longitudinal strain values computed from vendor-specific and vendor-independent analyses of images acquired using ultrasound systems from different vendors.Ten freshly harvested porcine hearts were studied. Each heart was mounted on a custom designed phantom and driven to simulate normal cardiac motion. Cardiac rotation was digitally controlled and held constant at 5°, while pumped stroke volume (SV ranged from 30-70ml. Full-volume image data was acquired using three different ultrasound systems from different vendors. The image data was analyzed for longitudinal and circumferential strains (LS, CS using both vendor-specific and vendor-independent analysis packages.Good linear relationships were observed for each vendor-specific analysis package for both CS and LS at the mid-anterior segment, with correlation coefficients ranging from 0.82-0.91 (CS and 0.86-0.89 (LS. Comparable linear regressions were observed for results determined by a vendor independent program (CS: R = 0.82-0.89; LS: R = 0.86-0.89. Variability between analysis packages was examined via a series of ANOVA tests. A statistical difference was found between vendor-specific analysis packages (p0.05.Circumferential and longitudinal regional strain values differ when quantified by vendor-specific analysis packages; however, this variability is mitigated by use of a vendor-independent quantification method. These results suggest that echocardiograms acquired using different ultrasound systems could be meaningfully compared using vendor-independent software.
Staphylococcus aureus is a dangerous pathogen that causes a variety of severe diseases. The virulence of S. aureus is defined by a large repertoire of virulence factors, among which secreted toxins play a preeminent role. Many S. aureus toxins damage biological membranes, leading to cell death. In particular, S. aureus produces potent hemolysins and leukotoxins. Among the latter, some were recently identified to lyse neutrophils after ingestion, representing an especially powerful weapon agai...
Daghighi, Seyedmojtaba; Sjollema, Jelmer; Jaspers, Valery; de Boer, Leonie; Zaat, Sebastian A J; Dijkstra, Rene J B; van Dam, Gooitzen M; van der Mei, Henny C; Busscher, Henk J
Biomaterials are increasingly used for the restoration of human function, but can become infected as a result of peri- or early post-operative bacterial contamination, although biomaterial-associated infections (BAIs) can also initiate at any time from hematogenous spreading of bacteria from an infection elsewhere in the body. Infecting bacteria in BAIs not only seek shelter in their own protective biofilm matrix, but also hide in surrounding tissue. This study compares staphylococcal persistence on and around a degradable and non-degradable surgical mesh through the use of longitudinal bioluminescence imaging in a murine model, including histological evaluation of surrounding tissue after sacrifice. Surgical meshes were first contaminated with bioluminescent Staphylococcus aureus Xen29 and subsequently subcutaneously implanted in mice. Bioluminescent staphylococci persisted on and around non-degradable meshes during the 28-day course of the study, whereas bioluminescence returned to control levels and bacteria disappeared from surrounding tissues once a degradable mesh had fully dissolved. Thus the application of degradable biomaterials yields major advantages with respect to the prevention of BAIs, as dissolution of the implant not only is associated with elimination of the protective biofilm mode of growth of the infecting organisms, but also allows the immune system to clear the surrounding tissue from infecting organisms. PMID:22824527
Levin, Todd P.; Suh, Byungse; Axelrod, Peter; Truant, Allan L.; Fekete, Thomas
The erm gene product confers clindamycin resistance on Staphylococcus aureus. We report a clindamycin clinical failure where resistance developed on therapy in a D-test-positive strain. D tests of 91 clindamycin-susceptible, erythromycin-resistant S. aureus isolates showed that 68% of methicillin-susceptible and 12.3% of methicillin-resistant S. aureus strains were D-test positive.
Kono, M; Sasatsu, M; O'Hara, K; Shiomi, Y.; HAYASAKA, T.
The mechanism of resistance to some cephalosporins in Staphylococcus aureus strains was investigated with high-pressure liquid chromatography and nuclear magnetic resonance spectrometry. Drug inactivation by penicillinase was found to be the main mechanism of resistance to cefazolin, cephaloridine, and cephalothin in S. aureus.
Ince, Dilek; Zhang, Xiamei; Hooper, David C.
Moxifloxacin has enhanced potency against Staphylococcus aureus, lower propensity to select for resistant mutants, and higher bactericidal activity against highly resistant strains than ciprofloxacin. Despite similar activity against purified S. aureus topoisomerase IV and DNA gyrase, it selects for topoisomerase IV mutants, making topoisomerase IV the preferred target in vivo.
Kali, Arunava; Stephen, Selvaraj; Umadevi, Sivaraman; Kumar, Shailesh; Joseph, Noyal Mariya; Srirangaraj, Sreenivasan
Background: Methicillin resistance in Staphylococcus aureus is associated with multidrug resistance, an aggressive course, increased mortality and morbidity in both community and health care facilities. Monitoring of newly emerging and prevalent Methicillin Resistant Staphylococcus aureus (MRSA) strains for their resistance patterns to conventional as well as novel drugs, are essential for infection control.
Background: Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a promising novel method for quantification of myocardial wall mechanics from standard steady-state free precession (SSFP) images. We sought to determine whether magnetic field strength affects the intra-observer reproducibility of CMR-FT strain analysis. Methods: We studied 2 groups, each consisting of 10 healthy subjects, at 1.5 T or 3 T Analysis was performed at baseline and after 4 weeks using dedicated CMR-FT prototype software (Tomtec, Germany) to analyze standard SSFP cine images. Right ventricular (RV) and left ventricular (LV) longitudinal strain (EllRV and EllLV) and LV long-axis radial strain (ErrLAX) were derived from the 4-chamber cine, and LV short-axis circumferential and radial strains (EccSAX, ErrSAX) from the short-axis orientation. Strain parameters were assessed together with LV ejection fraction (EF) and volumes. Intra-observer reproducibility was determined by comparing the first and the second analysis in both groups. Results: In all volunteers resting strain parameters were successfully derived from the SSFP images. There was no difference in strain parameters, volumes and EF between field strengths (p > 0.05). In general EccSAX was the most reproducible strain parameter as determined by the coefficient of variation (CV) at 1.5 T (CV 13.3% and 46% global and segmental respectively) and 3 T (CV 17.2% and 31.1% global and segmental respectively). The least reproducible parameter was EllRV (CV 1.5 T 28.7% and 53.2%; 3 T 43.5% and 63.3% global and segmental respectively). Conclusions: CMR-FT results are similar with reasonable intra-observer reproducibility in different groups of volunteers at 1.5 T and 3 T. CMR-FT is a promising novel technique and our data indicate that results might be transferable between field strengths. However there is a considerable amount of segmental variability indicating that further refinements are needed before CMR-FT can be fully
Cohen, M. L.; Wong, E. S.; Falkow, S
During a 7-month period in 1978 to 1979, 31 patients and personnel at a Kentucky hospital were colonized or infected with a Staphylococcus aureus strain resistant to clindamycin, erythromycin, gentamicin, methicillin, penicillin, and tetracycline. S. epidermidis with similar antibiotic resistance patterns had been isolated in this hospital in the year before the S. aureus outbreak. A 32-megadalton R-plasmid, pUW3626, mediating resistance to penicillin and gentamicin, was present in these isol...
Budd, Kathleen E; Mitchell, Jennifer; Keane, Orla M
Bovine mastitis is the most costly disease to the dairy industry worldwide with Staphylococcus aureus commonly associated with intramammary infections that are persistent and refractory to treatment. The strains of S. aureus that cause mastitis predominantly belong to a number of well-described bovine-adapted lineages. The objective of this study was to determine if a variety of potential virulence traits were associated with lineage. Bovine-adapted S. aureus isolates (n=120), belonging to lineages CC97, CC151 and ST136, were tested for their ability to adhere to and internalise within cultured bovine mammary epithelial cells (bMEC), to bind bovine fibronectin, to form a biofilm in TSB, TSB+1% glucose and TSB+4% NaCl, and to induce an immune response from bMEC. There were no significant differences between the lineages in ability to adhere to or internalise within bMEC although there were significant differences between individual isolates. For lineages CC97 and ST136, mammalian cell adherence was correlated with the ability to bind bovine fibronectin, however isolates from CC151 could not bind bovine fibronectin in vitro, but adhered to bMEC in a fibronectin-independent manner. There were significant differences between the lineages in ability to form a biofilm in all three growth media with ST136 forming the strongest biofilm while CC151 formed the weakest biofilm. Lineages also differed in their ability to elicit an immune response from bMEC with CC97 eliciting a stronger immune response than CC151 and ST136. These data indicate the potential for both lineage and strain-specific virulence and a strain-specific response to infection in vivo and caution against extrapolating an effect from a single strain of S. aureus to draw conclusions regarding virulence or the host response to infection in unrelated lineages. PMID:27259823
Full Text Available Linezolid is the only antibiotic available as an oral formulation for resistant staphylococcal infections. It is effective in skin and soft tissue infections, nosocomial pneumonias including VAP, infective endocarditis and MRSA meningitis. It is also effective in the eradication of both nasal and throat colonization of MRSA. Its high bioavailability and post antibiotic effect, ease of switching to oral therapy during its use and the fact that it can be used in patients of all ages, also in patients with liver disease and poor kidney function and its increased effectiveness over glycopeptides makes this drug a precious drug in the treatment of resistant staphylococcal infections. Linezolid resistance in staphylococcus is defined as a linezolid MIC of and #8805;8 mg/L. Reported Linezolid resistance in India and elsewhere is 2-20%. There is clonal dissemination of Linezolid Resistant Staphylococcus aureus (LRSA within or across health care settings which demands continuous surveillance to determine the emergent risk of resistance strains and to establish guidelines for appropriate use. Clinical laboratories should confirm any LRSA preferably by a second method, prior to using linezolid for serious infections. Effective surveillance, more judicious use of this antibiotic, avoiding linezolid usage for empiric therapy in hospital acquired staphylococcus infections, optimization of the pharmacological parameters of the antibiotics in specific clinical situation, decreasing bacterial load by timely surgical debridement or drainage of collections, use of combination therapies would prevent the emergence of resistance to linezolid in staphylococcus aureus. [Int J Res Med Sci 2014; 2(4.000: 1253-1256
Giezendanner, N; Meyer, B; Gort, M; Müller, P; Zweifel, C
Four hours after the consumption of raw goat milk, three Swiss children came down with emesis and diarrhea in July 2008. First investigations showed that the milk originated from a goat suffering from clinical mastitis (Staphylococcus aureus). In the milk sample from the untreated left udder, Staphylococcus aureus counts reached 5.0 x 10(7) CFU ml(-1). By PCR, the gene for the staphylococcal enterotoxin D was found in isolated strains. The consumption of raw milk is rarely associated with Staphylococcus aureus intoxications. Due to the flora naturally present in raw milk, Staphylococcus aureus normally cannot multiply sufficiently. However, in the present case, high Staphylococcus aureus counts were already present in the milk due to the mastitis of the goat. This amount sufficed to cause a Staphylococcus aureus intoxication in the children. PMID:19565455
58株致肺炎金黄色葡萄球菌耐药性分布及耐药菌体外诱导耐药情况分析%Drug Resistance Distribution of 58 Strains of Staphylococcus Aureus Leading to Pneumonia and Situation Analysis of Drug-fast Bacteria in Vitro Induc-tion of Resistance
目的：以58株金黄色葡萄球菌为例，分析其耐药性分布，指导临床抗生素的合理使用。通过体外诱导耐药，初步探讨其耐药机制。方法整群选取该院2013年3月—2014年3月临床分离得到的58株金黄色葡萄球菌，进行药敏实验，分析其耐药性分布。通过体外诱导法建立金黄色葡萄球菌的耐药模型，初步探讨其耐药机制。结果58株金黄色葡萄球菌中，分离出32株耐甲氧西林金黄色葡萄球菌（MRSA），占金黄色葡萄球菌的55.2%。金黄色葡萄球菌主要分布在ICU病房、呼吸内科以及神经外科。主要感染标本为痰液和分泌物。所分离到的58株菌对万古霉素和利奈唑胺均敏感，青霉素耐药率为98.3%。结论金黄色葡萄球菌主要分布在门诊、ICU等科室，且耐药菌株的数量已不容乐观，应引起临床上的足够重视，加强抗生素合理使用的管理以及对金黄色葡萄球菌感染的监测。%Objective To analyze the drug resistance distribution by taking 58 strains of staphylococcus aureus for example in order to guide the rational use of clinical antibiotics and preliminarily discuss the drug resistance mechanism by in vitro induction of resistance. Methods 58 strains of Staphylococcus aureus obtained by clinical isolates from March 2013 to March 2014 were selected and the drug resistance distribution of them were analyzed by drug sensitivity test, the drug re-sistance model of staphylococcus aureus was built by in vitro induction method and its drug resistance mechanism was pre-liminarily discussed. Results 32 strains of staphylococcus aureus (MRSA) were separated from 58 strains of staphylococcus aureus, accounting for 55.2% of staphylococcus aureus, staphylococcus aureus was mainly distributed in the ICU ward, res-piratory department of internal medicine and department of neurosurgery, the main infection specimens were sputum and se-cretion, the isolated 58 strains were
Sauget, Marlène; van der Mee-Marquet, Nathalie; Bertrand, Xavier; Hocquet, Didier
Within the last decade methicillin-resistant Staphylococcus aureus belonging to CC398 has become a worldwide threat associated with livestock. More recently, methicillin-susceptible S. aureus (MSSA) belonging to CC398 have been increasingly reported as a cause of invasive infections in patients without livestock contact. It appears therefore necessary to implement a convenient tool for the surveillance this emerging pathogen. We evaluated the MALDI-TOF MS as a tool for rapid detection of S. aureus CC398. We used 626 S. aureus isolates characterized by a CC398-specific PCR, to constitute independent training (300 isolates including 60 isolates CC398) and validation sets (326 isolates including 82 isolates CC398). Fifteen peak biomarkers of CC398 were identified from the mass spectra of the training set. Ninety four % (307 of 326) of strains of the validation set were well assigned with an overall sensitivity of 93% and a specificity of 95%. Six CC398 and 13 non-CC398 isolates were misclassified. With MALDI-TOF MS, clinical laboratories could rapidly detect S. aureus CC398 associated with a higher mortality in hospitalized patients. PMID:27192668
Rahat Ejaz; Usman A Ashfaq; Sobia Idrees
Objective: To determine resistance patterns of Staphylococcus aureus (S. aureus) isolated from different areas of Pakistan and to identify antimicrobial agents against multi-drug resistant S.aureus strains. Methods: A total of 67 samples (sewerage, nasal and milk) were collected from different farm areas of Pakistan to identify local strains of S. aureus. Sixteen out of 67 samples were positive for S.aureus. Only 6 out of 16 S. aureus strains showed resistance to antibiotics. Then the antibacterial effect of 29 medicinal plants was evaluated on these S. aureus isolates and a standard S. aureus strain ATCC 25923. The solvents used for the extraction of plants were acetone, dimethyl sulfoxide and methanol. The in vitro antibacterial activity was performed using agar disc diffusion method. Moreover, minimum inhibitory concentration of effective medicinal plant extracts was identified through micro-dilution method to find out their 50% inhibitory concentration.Results:Plant extracts of 5 medicinal plants (Psidium guajava, Nigella sativa, Piper nigrum, Valeriana jatamansi, and Cucurbita pepo) exhibited antibacterial activity against locally isolated multidrug resistant strains of S. aureus. The minimum inhibitory concentration of these extracts was ranged from 0.328 to 5.000 mg/mL. Conclusions: Plant extracts of Psidium guajava, Piper nigrum seed, Valeriana jatamansi, Cucurbita pepo and Nigella sativa showed significant in vitro antibacterial activity and thus, such findings may serve as valuable contribution in the treatment of infection and may contribute to the development of potential antimicrobial agents against multi drug resistant strains of S. aureus.
Full Text Available Objective: To determine resistance patterns of Staphylococcus aureus (S. aureus isolated from different areas of Pakistan and to identify antimicrobial agents against multi-drug resistant S. aureus strains. Methods: A total of 67 samples (sewerage, nasal and milk were collected from different farm areas of Pakistan to identify local strains of S. aureus. Sixteen out of 67 samples were positive for S. aureus. Only 6 out of 16 S. aureus strains showed resistance to antibiotics. Then the antibacterial effect of 29 medicinal plants was evaluated on these S. aureus isolates and a standard S. aureus strain ATCC 25923. The solvents used for the extraction of plants were acetone, dimethyl sulfoxide and methanol. The in vitro antibacterial activity was performed using agar disc diffusion method. Moreover, minimum inhibitory concentration of effective medicinal plant extracts was identified through micro-dilution method to find out their 50% inhibitory concentration. Results: Plant extracts of 5 medicinal plants (Psidium guajava, Nigella sativa, Piper nigrum, Valeriana jatamansi, and Cucurbita pepo exhibited antibacterial activity against locally isolated multidrug resistant strains of S. aureus. The minimum inhibitory concentration of these extracts was ranged from 0.328 to 5.000 mg/mL. Conclusions: Plant extracts of Psidium guajava, Piper nigrum seed, Valeriana jatamansi, Cucurbita pepo and Nigella sativa showed significant in vitro antibacterial activity and thus, such findings may serve as valuable contribution in the treatment of infection and may contribute to the development of potential antimicrobial agents against multi drug resistant strains of S. aureus
Ordway, Diane; Viveiros, Miguel; Leandro, Clara; Arroz, Maria Jorge; Amaral, Leonard
The effect of thioridazine (TZ) was studied on the killing activity of human peripheral blood monocyte derived macrophages (HPBMDM) and of human macrophage cell line THP-1 at extracellular concentrations below those achievable clinically. These macrophages have nominal killing activity against bacteria and therefore, would not influence any activity that the compounds may have against intracellular localised Staphylococcus aureus. The results indicated that whereas TZ has an in vitro minimum inhibitory concentration (MIC) against the strains of S. aureus of 18, 0.1 mg/l of TZ in the medium completely inhibits the growth of S. aureus that has been phagocytosed by macrophages. The latter concentration was non-toxic to macrophages, did not cause cellular expression of activation marker CD69 nor induction of CD3+ T cell production of IFN-gamma, but blocked cellular proliferation and down-regulated the production of T cell-derived cytokines (IFN-gamma, IL-5). These results suggest that TZ induces intracellular bactericidal activities independent of the capacity to generate Type 1 responses against S. aureus. PMID:12127709
Full Text Available Clostridium botulinum (group III, Clostridium novyi and Clostridium haemolyticum are well-known pathogens causing animal botulism, gas gangrene/black disease, and bacillary hemoglobinuria, respectively. A close genetic relationship exists between the species, which has resulted in the collective term C. novyi sensu lato. The pathogenic traits in these species, e.g., the botulinum neurotoxin and the novyi alpha toxin, are mainly linked to a large plasmidome consisting of plasmids and circular prophages. The plasmidome of C. novyi sensu lato has so far been poorly characterized. In this study we explored the genomic relationship of a wide range of strains of C. novyi sensu lato with a special focus on the dynamics of the plasmidome. Twenty-four genomes were sequenced from strains selected to represent as much as possible the genetic diversity in C. novyi sensu lato. Sixty-one plasmids were identified in these genomes and 28 of them were completed. The genomic comparisons revealed four separate lineages, which did not strictly correlate with the species designations. The plasmids were categorized into 13 different plasmid groups on the basis of their similarity and conservation of plasmid replication or partitioning genes. The plasmid groups, lineages and species were to a large extent entwined because plasmids and toxin genes had moved across the lineage boundaries. This dynamic process appears to be primarily driven by phages. We here present a comprehensive characterization of the complex species group C. novyi sensu lato, explaining the intermixed genetic properties. This study also provides examples how the reorganization of the botulinum toxin and the novyi alpha toxin genes within the plasmidome has affected the pathogenesis of the strains.
Fabiola Gutierrez-Orozco; Thomas-Ahner, Jennifer M; Jeffrey D. Galley; Bailey, Michael T.; Clinton, Steven K.; Lesinski, Gregory B.; Failla, Mark L.
Beverages and supplements prepared from mangosteen fruit are claimed to support gut health and immunity, despite the absence of supporting evidence from clinical trials. We recently reported that α-mangostin (α-MG), the most abundant xanthone in mangosteen fruit, altered the intestinal microbiome, promoted dysbiosis, and exacerbated colitis in C57BL/6J mice. The objective of this study was to determine whether induction of dysbiosis by dietary α-MG is limited to the C57BL/6J strain or represe...
Roubíček, Tomáš; Valdman, Jan
-, - (2016). ISSN 1081-2865 R&D Projects: GA ČR GA14-15264S; GA ČR GA13-18652S Institutional support: RVO:67985556 ; RVO:61388998 Keywords : rate-independent systems * nonsmooth continuum mechanics * incomplete ductile damage Subject RIV: BA - General Mathematics Impact factor: 1.298, year: 2014 http://library.utia.cas.cz/separaty/2016/MTR/valdman-0458555.pdf
The Emergence and Spread of Multiple Livestock-Associated Clonal Complex 398 Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Strains among Animals and Humans in the Republic of Ireland, 2010-2014.
Gráinne I Brennan
Full Text Available Clonal complex (CC 398 methicillin-resistant Staphylococcus aureus (MRSA and methicillin-susceptible S. aureus (MSSA are associated with carriage and infection among animals and humans but only a single case of CC398 MRSA has been reported in the Republic of Ireland (ROI. The present study investigated the molecular epidemiology of CC398 MRSA (n = 22 and MSSA (n = 10 from animals and humans in the ROI from 2010-2014. Isolates underwent antimicrobial susceptibility testing, spa typing, DNA microarray profiling and PCR for CC398-associated resistance genes. All MRSA underwent SCCmec IV or V subtyping. Four distinct CC398-MRSA incidents were identified from (i a man in a nursing home (spa type t011-SCCmec IVa, immune evasion complex (IEC negative, (ii a horse and veterinarian who had recently travelled to Belgium (t011-IVa, IEC positive, (iii pigs (n = 9 and farm workers (n = 9 on two farms, one which had been restocked with German gilts and the other which was a finisher farm (t034-VT, IEC negative, 3/9 pigs; t011-VT, IEC negative, 6/9 pigs & 9/9 farm workers, and (iv a child who had worked on a pig farm in the UK (t034-VT, IEC negative. Isolates also carried different combinations of multiple resistance genes including erm(A, erm(B, tet(K, tet(M & tet(L, fexA, spc, dfrG, dfrK aacA-aphD and aadD further highlighting the presence of multiple CC398-MRSA strains. CC398 MSSA were recovered from pigs (n = 8 and humans (n = 2. CC398 MSSA transmission was identified among pigs but zoonotic transmission was not detected with animal and human isolates exhibiting clade-specific traits. This study highlights the importation and zoonotic spread of CC398 MRSA in the ROI and the spread of CC398 MSSA among pigs. Increased surveillance is warranted to prevent further CC398 MRSA importation and spread in a country that was considered CC398 MRSA free.
Zhao, Wei; Hu, Haixia; Zsak, Laszlo; Yu, Qingzhong; Yang, Zengqi
Newcastle disease virus (NDV) can cause serious diseases and substantial economic losses to the poultry industry. To gain a better understanding of NDV pathogenesis, several reverse genetics systems for different NDV strains have been established. However, the construction of infectious cDNA clone by conventional restriction digestion/ligation cloning methods is a time-consuming process and has many drawbacks by its nature. To address the problems, we employed a novel and robust ligation-independent cloning (LIC) method for efficient assembly of multiple DNA fragments. Using this method, we successfully generated a NDV minigenome construct within three weeks by assembling RT-PCR products of the VG/GA strain genomic termini and a cDNA coding for the green fluorescence protein (GFP), as a reporter, into a modified pBluescript vector. Co-transfection of the NDV minigenome with three supporting plasmids expressing the N, P, and L proteins into MVA-T7 infected HEp-2 cells and followed by infection with NDV VG/GA resulted in the minigenome replication, transcription, and packaging as evidenced by the reporter gene GFP expression. These results suggest that this LIC approach is a powerful tool for all sequence-independent DNA cloning and multi-DNA fragment assembly, which has a potential application for rapid development of gene therapy and recombinant vaccines. PMID:23928042
Full Text Available Beverages and supplements prepared from mangosteen fruit are claimed to support gut health and immunity, despite the absence of supporting evidence from clinical trials. We recently reported that α-mangostin (α-MG, the most abundant xanthone in mangosteen fruit, altered the intestinal microbiome, promoted dysbiosis, and exacerbated colitis in C57BL/6J mice. The objective of this study was to determine whether induction of dysbiosis by dietary α-MG is limited to the C57BL/6J strain or represents a more generic response to chronic intake of the xanthone on the gut microbiota of mice. C3H, Balb/c, Nude FoxN1nu, and C57BL/6J mice, each demonstrating unique microbiomes, were fed standard diet or diet containing 0.1% α-MG for four weeks. Dietary α-MG significantly altered the cecal and colonic microbiota in all four strains of mice, promoting a reduction in generally assumed beneficial bacterial groups while increasing the abundance of pathogenic bacteria. Consumption of α-MG was associated with reduced abundance of Firmicutes and increased abundance of Proteobacteria. The abundance of Lachnospiraceae, Ruminococcaceae, and Lactobacillaceae was reduced in α-MG-fed mice, while that of Enterobacteriaceae and Enterococcaceae was increased. Dietary α-MG also was associated with increased proliferation of colonic epithelial cells, infiltration of immune cells, infiltration of immune cells and increased fluid content in stool. These results suggest that ingestion of pharmacologic doses of xanthones in mangosteen-containing supplements may adversely alter the gut microbiota and should be used with caution.
Gutierrez-Orozco, Fabiola; Thomas-Ahner, Jennifer M; Galley, Jeffrey D; Bailey, Michael T; Clinton, Steven K; Lesinski, Gregory B; Failla, Mark L
Beverages and supplements prepared from mangosteen fruit are claimed to support gut health and immunity, despite the absence of supporting evidence from clinical trials. We recently reported that α-mangostin (α-MG), the most abundant xanthone in mangosteen fruit, altered the intestinal microbiome, promoted dysbiosis, and exacerbated colitis in C57BL/6J mice. The objective of this study was to determine whether induction of dysbiosis by dietary α-MG is limited to the C57BL/6J strain or represents a more generic response to chronic intake of the xanthone on the gut microbiota of mice. C3H, Balb/c, Nude FoxN1nu, and C57BL/6J mice, each demonstrating unique microbiomes, were fed standard diet or diet containing 0.1% α-MG for four weeks. Dietary α-MG significantly altered the cecal and colonic microbiota in all four strains of mice, promoting a reduction in generally assumed beneficial bacterial groups while increasing the abundance of pathogenic bacteria. Consumption of α-MG was associated with reduced abundance of Firmicutes and increased abundance of Proteobacteria. The abundance of Lachnospiraceae, Ruminococcaceae, and Lactobacillaceae was reduced in α-MG-fed mice, while that of Enterobacteriaceae and Enterococcaceae was increased. Dietary α-MG also was associated with increased proliferation of colonic epithelial cells, infiltration of immune cells, infiltration of immune cells and increased fluid content in stool. These results suggest that ingestion of pharmacologic doses of xanthones in mangosteen-containing supplements may adversely alter the gut microbiota and should be used with caution. PMID:25621505
Dungu, B; BRETT, B; Macdonald, R.; S. Deville; Dupuis, L.; Theron, J.; R.R. Bragg
The present study was designed to assess and compare three different formulations of the new Onderstepoort infectious coryza (IC) quadrivalent vaccine, which contain an NAD-independent strain of Avibacterium paragallinarum (previously known as Haemophilus paragallinarum), and a commercial IC vaccine, not containing an NAD-independent strain, for their safety and ability to protect chickens of varying ages against virulent challenges with four different serovars of A. paragallinarum, inc...
Staphylococcus aureus is a typical human pathogen. Some animal S. aureus lineages have derived from human strains following profound genetic adaptation determining a change in host specificity. Due to the close relationship of animals with the environmental microbioma and resistoma, animal staphylococcal strains also represent a source of resistance determinants. Methicillin-resistant S. aureus (MRSA) emerged fifty years ago as a nosocomial pathogen but in the last decade it has also become...
Taruna Bhati; Prerna Nathawat; Sandeep Kumar Sharma; Rahul Yadav; Jyoti Bishnoi; Anil Kumar Kataria
Aim: The virulence-associated protein-A of Staphylococcus aureus, encoded by spa gene shows a variation in length in different strains. In this study, the spa gene variation in S. aureus strains was studied which were isolated from subclinical cases of bovine mastitis. Materials and Methods: About 38 isolates of S. aureus were recovered from Holstein–Friesian (HF) crossbred (n=16) and Rathi cattle (n=22) with subclinical mastitis as per standard procedures, and these isolates were subjecte...
Bhati, Taruna; Nathawat, Prerna; Sharma, Sandeep Kumar; Yadav, Rahul; Bishnoi, Jyoti; Kataria, Anil Kumar
Aim: The virulence-associated protein-A of Staphylococcus aureus, encoded by spa gene shows a variation in length in different strains. In this study, the spa gene variation in S. aureus strains was studied which were isolated from subclinical cases of bovine mastitis. Materials and Methods: About 38 isolatesof S. aureus were recovered from Holstein–Friesian (HF) crossbred (n=16) and Rathi cattle (n=22) with subclinical mastitis as per standard procedures, and these isolates were subjected to...
Pedro J. Esteves
Full Text Available Rabbit hemorrhagic disease is caused by a calicivirus, rabbit hemorrhagic disease virus (RHDV, which is responsible for high mortality in domestic and wild European rabbits (Oryctolagus cuniculus. RHDV strains were sequenced from wild European rabbits (Oryctolagus cuniculus algirus collected in the Azorean island of Pico, Portugal. Phylogenetic analyses showed that the Pico RHDV strains diverge from all of the others described so far, but cluster with the genogroups 1–5 (G1–G5. The genetic distance between the Pico RHDV sequences and each G1, G2 and G3–G5 genogroup (~0.08 is compatible with an RHDV introduction at least 17 years ago. Our results show that in Pico, RHDV is the outcome of an independent evolution from the original RHDV strain that appeared in its European rabbit population. These are the first sequences of RHDV obtained in the subspecies O. c. algirus, outside of its original region, the Iberian Peninsula. Furthermore, we discuss the risk of rabbit translocations from the Azores to the Iberian Peninsula, where the rabbit wild populations are suffering high mortalities.
A sensitive assay for staphylococcal nuclease involving incubation of the enzyme sample with heat-denatured [3H] thymidine labelled DNA from E.coli, precipitation with trichloroacetic acid and measurement of the radioactivity of acid-soluble nucleotides released has been developed. The assay is sensitive enough to be used for comparing the levels of nucleases elaborated by different strains of S. aureus as well as for determining the extent of contamination of S. aureus in food and water samples even at levels at which the conventional spectrophotometric and toluidine blue-DNA methods are totally inadequate. (author). 26 refs., 3 figs ., 3 tabs
Jung, Byeong Su; Lee, Yong Ju; Lee, Na-Kyoung; Kim, Hyoun Wook; Oh, Mi-Hwa; Paik, Hyun-Dong
The aim of this study was to investigate the antimicrobial resistance profiles of and the enterotoxin gene distribution in 4 strains of Staphylococcus aureus (S10-2, S10-3, S12-2, and S13-2) isolated from 90 bulgogi samples. The S. aureus enterotoxin H gene (seh) was found in all the strains, while the S. aureus enterotoxin A gene (sea) was found only in 3 of the 4 strains. The S10-2 strain expressed a combination of enterotoxin genes - seg, seh, sei, sej, selm, and seln. The strains S10-2 an...
Boss, R; Cosandey, A; Luini, M; Artursson, K; Bardiau, M; Breitenwieser, F; Hehenberger, E; Lam, Th; Mansfeld, M; Michel, A; Mösslacher, G; Naskova, J; Nelson, S; Podpečan, O; Raemy, A; Ryan, E; Salat, O; Zangerl, P; Steiner, A; Graber, H U
Staphylococcus aureus is globally one of the most important pathogens causing contagious mastitis in cattle. Previous studies using ribosomal spacer (RS)-PCR, however, demonstrated in Swiss cows that Staph. aureus isolated from bovine intramammary infections are genetically heterogeneous, with Staph. aureus genotype B (GTB) and GTC being the most prominent genotypes. Furthermore, Staph. aureus GTB was found to be contagious, whereas Staph. aureus GTC and all the remaining genotypes were involved in individual cow disease. In addition to RS-PCR, other methods for subtyping Staph. aureus are known, including spa typing and multilocus sequence typing (MLST). They are based on sequencing the spa and various housekeeping genes, respectively. The aim of the present study was to compare the 3 analytic methods using 456 strains of Staph. aureus isolated from milk of bovine intramammary infections and bulk tanks obtained from 12 European countries. Furthermore, the phylogeny of animal Staph. aureus was inferred and the zoonotic transfer of Staph. aureus between cattle and humans was studied. The analyzed strains could be grouped into 6 genotypic clusters, with CLB, CLC, and CLR being the most prominent ones. Comparing the 3 subtyping methods, RS-PCR showed the highest resolution, followed by spa typing and MLST. We found associations among the methods but in many cases they were unsatisfactory except for CLB and CLC. Cluster CLB was positive for clonal complex (CC)8 in 99% of the cases and typically positive for t2953; it is the cattle-adapted form of CC8. Cluster CLC was always positive for tbl 2645 and typically positive for CC705. For CLR and the remaining subtypes, links among the 3 methods were generally poor. Bovine Staph. aureus is highly clonal and a few clones predominate. Animal Staph. aureus always evolve from human strains, such that every human strain may be the ancestor of a novel animal-adapted strain. The zoonotic transfer of IMI- and milk-associated strains
Full Text Available Context: Staphylococcus aureus is one of the most devastating human pathogen. The organism has a differential ability to spread and cause outbreak of infections. Characterization of these strains is important to control the spread of infection in the hospitals as well as in the community. Aim: To identify the currently existing phage groups of Staphylococcus aureus, their prevalence and resistance to antibiotics. Materials and Methods: Study was undertaken on 252 Staphylococcus aureus strains isolated from clinical samples. Strains were phage typed and their resistance to antibiotics was determined following standard microbiological procedures. Statistical Analysis: Chi square test was used to compare the antibiotic susceptibility between methicillin resistant Staph. aureus (MRSA and methicillin sensitive S. aureus (MSSA strains. Results: Prevalence of MRSA and MSSA strains was found to be 29.36% and 70.65% respectively. Of these 17.56% of MRSA and 40.44% of MSSA strains were community acquired. All the MSSA strains belonging to phage type 81 from the community were sensitive to all the antibiotics tested including clindamycin and were resistant to penicillin. Forty five percent strains of phage group III and 39% of non-typable MRSA strains from the hospital were resistant to multiple antibiotics. Conclusion: The study revealed that predominant phage group amongst MRSA strains was phage group III and amongst MSSA from the community was phage group NA (phage type 81. MSSA strains isolated from the community differed significantly from hospital strains in their phage type and antibiotic susceptibility. A good correlation was observed between community acquired strains of phage type 81 and sensitivity to gentamycin and clindamycin.
Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); Yamazaki, N; Taniguchi, H; Fujimura, S.
Staphylococci from samples of human saliva were isolated on staphylococcal-selective agar plates. These strains were tested for the inhibition of the growth of Staphylococcus aureus FDA209P. The frequency of inhibitory strains among all of the staphylococcal isolates was 5.2%. Strain IYS2, which formed the biggest inhibitory zone against the growth of the indicator strain, was used as the producer of bacteriocin. IYS2 was identified to be S. aureus, based on its biological properties. The bac...