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Microbial Drug Resistance (Larchmont,... Sep 2018This study was conducted to determine the occurrence of antimicrobial resistance and enterotoxin-encoding genes (EEGs) in Staphylococcus spp. recovered from equipment...
This study was conducted to determine the occurrence of antimicrobial resistance and enterotoxin-encoding genes (EEGs) in Staphylococcus spp. recovered from equipment used to prepare hospital meals, in a university hospital in Rio de Janeiro, Brazil. Sixty samples were collected from semi-industrial equipment (one blender and one mixer) in the hospital's kitchen. Resistance genes and SCCmec types were detected by PCR. From the 40 isolates of Staphylococcus spp. identified, 8 were Staphylococcus aureus. Thirty-two (80%) Staphylococcus spp. isolates were resistant to at least one antimicrobial agent. Resistance genetic determinants were detected: erm gene (Staphylococcus epidermidis [n = 2]; Staphylococcus hominis [n = 1]), mecA gene (S. epidermidis [n = 2]), and aa(6')-aph(2'') gene (Staphylococcus caprae [n = 1], S. epidermidis [n = 2], S. hominis [n = 1], Staphylococcus pausteri [n = 1], Staphylococcus simulans [n = 1], and Staphylococcus warneri [n = 1]). The presence of at least one EEG in 83% (n = 33) of the isolates was identified. Two strains of S. epidermidis were methicillin-resistant S. epidermidis (MRSE) and harboring SCCmec type IV. Staphylococcus spp. contaminated some hospital kitchen's equipment, indicating that hygiene procedures should be improved. Results also indicate that meals can be a vehicle to disseminate multiresistant Staphylococcus spp., including MRSE, and Staphylococcus with EEGs.
Topics: Adult; Anti-Bacterial Agents; Bacterial Proteins; Brazil; DNA, Bacterial; Enterotoxins; Female; Hospitals, University; Humans; Male; Methicillin Resistance; Microbial Sensitivity Tests; Middle Aged; Staphylococcal Infections; Staphylococcus
PubMed: 29653479
DOI: 10.1089/mdr.2016.0309 -
Journal of Applied Microbiology Mar 2017The aims of this study were to design, synthesize and to evaluate 2-hydroxy-3-phenylsulfanylmethyl-[1,4]-naphthoquinones against Gram-negative and Gram-positive...
AIMS
The aims of this study were to design, synthesize and to evaluate 2-hydroxy-3-phenylsulfanylmethyl-[1,4]-naphthoquinones against Gram-negative and Gram-positive bacterial strains, including methicillin-resistant Staphylococcus aureus (MRSA) and its biofilm, to probe for potential lead structures.
METHODS AND RESULTS
Thirty-six new analogues were prepared with good yields using a simple, fast, operational three-procedure reaction and a thiol addition to an ο-quinone methide using microwave irradiation. All compounds were tested against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Proteus mirabilis ATCC 15290, Serratia marcescens ATCC 14756, Klebsiella pneumoniae ATCC 4352, Enterobacter cloacae ATCC 23355, Enterococcus faecalis ATCC 29212, S. aureus ATCC 25923, Staphylococcus simulans ATCC 27851, Staphylococcus epidermidis ATCC 12228 and a hospital strain of MRSA. Their antibacterial activity was determined using the disc diffusion method, revealing the activity of 19 compounds, mainly against Gram-positive strains. Interestingly, the minimal inhibitory concentration ranges detected for the hit molecules (32-128 μg ml ) were within Clinical and Laboratory Standards Institute levels. Promisingly, compound 15 affected the MRSA strain, with a reduction of up to 50% in biofilm formation, which is better than vancomycin as biofilm forms a barrier against the antibiotic that avoids its action.
CONCLUSIONS
After probing 36 naphthoquinones for a potential antibacterial lead structure against the bacterial biofilm, we found that compound 15 should be explored further and also should be structurally modified in the near future to test against Gram-negative strains.
SIGNIFICANCE AND IMPACT OF THE STUDY
Since vancomycin is one of the last treatment options currently available, and it is unable to inhibit biofilm, the research of new antimicrobials is urgent. In this context, 2-hydroxy-3-phenylsulfanylmethyl-[1,4]-naphthoquinones proved to be a promising lead structure against MRSA and bacterial biofilm.
Topics: Anti-Bacterial Agents; Biofilms; Enterobacter cloacae; Enterococcus faecalis; Escherichia coli; Gram-Positive Bacteria; Humans; Klebsiella pneumoniae; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Naphthoquinones; Proteus mirabilis; Pseudomonas aeruginosa; Staphylococcus; Vancomycin
PubMed: 27930849
DOI: 10.1111/jam.13369 -
Journal of Applied Microbiology Sep 2011The objective of this study was to investigate the detection of SEE, SEG, SEH and SEI in strains of Staphylococcus aureus and coagulase-negative staphylococci (CNS)...
AIMS
The objective of this study was to investigate the detection of SEE, SEG, SEH and SEI in strains of Staphylococcus aureus and coagulase-negative staphylococci (CNS) using RT-PCR.
METHODS AND RESULTS
In this study, 90 Staph. aureus strains and 90 CNS strains were analysed by PCR for the detection of genes encoding staphylococcal enterotoxins (SE) E, G, H and I. One or more genes were detected in 54 (60%) Staph. aureus isolates and in 29 (32.2%) CNS isolates. Staphylococcus epidermidis was the most frequently isolated CNS species (n = 64, 71.1%), followed by Staphylococcus warneri (n = 8, 8.9%) and other species (Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus lugdunensis, Staphylococcus simulans, Staphylococcus saprophyticus and Staphylococcus xylosus: n = 18, 20%). The genes studied were detected in Staph. epidermidis, Staph. warneri, Staph. haemolyticus, Staph. hominis, Staph. simulans and Staph. lugdunensis. The highest frequency of genes was observed in Staph. epidermidis and Staph. warneri, a finding indicating differences in the pathogenic potential between CNS species and highlighting the importance of the correct identification of these micro-organisms. RT-PCR used for the detection of mRNA revealed the expression of SEG, SEH and/or SEI in 32 (59.3%) of the 90 Staph. aureus isolates, whereas expression of some of these genes was observed in 10 (34.5%) of the 90 CNS isolates.
CONCLUSIONS
Staphylococcus epidermidis was the most toxigenic CNS species. Among the other species, only Staph. warneri and Staph. lugdunensis presented a positive RT-PCR result. PCR was efficient in confirming the toxigenic capacity of Staph. aureus and CNS.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study permitted to confirm the toxigenic capacity of CNS to better characterize the pathogenic potential of this group of micro-organisms. In addition, it permitted the detection of SEG, SEH and SEI, enterotoxins that cannot be detected by commercially available immunological methods.
Topics: Brazil; Coagulase; DNA, Bacterial; Enterotoxins; Genes, Bacterial; Humans; Infant, Newborn; Reverse Transcriptase Polymerase Chain Reaction; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus
PubMed: 21672099
DOI: 10.1111/j.1365-2672.2011.05076.x -
Veterinary Research Mar 2011Coagulase-negative staphylococci (CNS) are in several countries the most common bacteria isolated in subclinical mastitis. To investigate the innate immune response of...
Coagulase-negative staphylococci (CNS) are in several countries the most common bacteria isolated in subclinical mastitis. To investigate the innate immune response of cows to infections with two common mastitis-causing CNS species, Staphylococcus epidermidis and Staphylococcus simulans, experimental intramammary infection was induced in eight cows using a crossover design. The milk somatic cell count (SCC), N-acetyl-β-D-glucosaminidase (NAGase) activity, milk amyloid A (MAA), serum amyloid A (SAA) and proinflammatory cytokines interleukin (IL)-1β, IL-8, and tumor necrosis factor α (TNF-α) were determined at several time points before and after challenge. All cows became infected and showed mild to moderate clinical signs of mastitis. The spontaneous elimination rate of the 16 infections was 31.3%, with no difference between species. Infections triggered a local cytokine response in the experimental udder quarters, but cytokines were not detected in the uninfected control quarters or in systemic circulation. The innate local immune response for S. simulans was slightly stronger, with significantly higher concentrations of IL-1β and IL-8. The IL-8 response could be divided into early, delayed, or combined types of response. The CNS species or persistency of infection was not associated with the type of IL-8 response. No significant differences were seen between spontaneously eliminated or persistent infections.
Topics: Acetylglucosaminidase; Animals; Cattle; Cell Count; Colony Count, Microbial; Cross-Over Studies; Cytokines; Enzyme-Linked Immunosorbent Assay; Female; Immunity, Innate; Mammary Glands, Animal; Mastitis, Bovine; Milk; Serum Amyloid A Protein; Species Specificity; Staphylococcal Infections; Staphylococcus; Staphylococcus epidermidis
PubMed: 21414189
DOI: 10.1186/1297-9716-42-49 -
Foods (Basel, Switzerland) May 2022and screened from Guizhou specialty food were used to prepare fermented pork loin ham. The sensory qualities and flavor profiles of fermented pork loin hams from 0 to...
and screened from Guizhou specialty food were used to prepare fermented pork loin ham. The sensory qualities and flavor profiles of fermented pork loin hams from 0 to 42 days were investigated in order to reveal the dynamics of fermented pork loin ham. The results show that total free amino acids (TFAA) content reached the highest value on the 35th day, and the umami amino acids, including aspartic acid (ASP), glutamic acid (GLU), glycine (GLY), and alanine (ALA), were the main amino acids in all periods. Notably, the RV coefficient (0.875) indicates that free amino acids (FAA) are highly correlated with the sensory score of the E-tongue. In terms of the volatile compounds identified, the esters content gradually increased between 7 and 42 days, and ethyl octanoate was the most abundant compound during all periods. These esters imparted a characteristic aroma component to the fermented pork loin ham. The most important finding was that the increase in the content of esters represented by octanoic acid-ethyl ester might be related to the increase in the content of FAA with the increase in fermentation time. Both the E-nose and E-tongue showed good discrimination ability for fermented tenderloin ham with different fermentation times, which was crucial in cases with large clusters. In addition, the multiple factor analysis (MFA) indicated that the E-nose aroma value might be the key factor in distinguishing fermented pork loin ham with different fermentation times.
PubMed: 35627071
DOI: 10.3390/foods11101501 -
Journal of Dairy Science Sep 2012Coagulase-negative staphylococci (CNS) are the most commonly isolated bacteria from goat milk. The goal of this study was to explore and describe differences between CNS...
Coagulase-negative staphylococci (CNS) are the most commonly isolated bacteria from goat milk. The goal of this study was to explore and describe differences between CNS species in persistence of intramammary infection (IMI) and in effect on somatic cell count (SCC) and milk yield (MY). Milk samples were collected from 530 does from 5 Dutch dairy goat herds on 3 occasions during 1 lactation. Coagulase-negative staphylococci species were identified at the species level by transfer RNA-intergenic spacer PCR (tDNA-PCR) followed by capillary electrophoresis. The most prevalent CNS species were Staphylococcus caprae, Staphylococcus epidermidis, Staphylococcus simulans, and Staphylococcus xylosus, but large differences were seen in species distribution between herds. Staphylococcus caprae and Staph. xylosus appeared to be more persistent than other species, but confidence intervals were overlapping. The effect of IMI caused by the 4 most prevalent CNS species on SCC and on MY was determined with linear regression models, and Staph. aureus and Corynebacterium bovis were included in the analyses as reference organisms. Most species were associated with a significantly higher SCC than noninfected udder halves, but the effect of CNS species on SCC was much smaller than the effect of Staph. aureus on SCC. We found a significant positive association between infection with Staph. caprae and MY. Intramammary infection caused by Staph. xylosus, on the other hand, had a negative association with milk yield, comparable to the effect of Staph. aureus, but these effects were not significantly different from zero. Intramammary infections with CNS species have a high prevalence in goats and are persistent, but have a limited effect on SCC compared with IMI with Staph. aureus. The effect of CNS species on MY differed between species, but differences were nonsignificant because limited numbers per species were available for analysis. Therefore, CNS species appear to behave as minor pathogens in goats, but larger studies are needed to give better estimates for the effect on MY.
Topics: Animals; Cell Count; Female; Goat Diseases; Goats; Lactation; Mastitis; Milk; Staphylococcal Infections; Staphylococcus; Staphylococcus epidermidis
PubMed: 22916911
DOI: 10.3168/jds.2012-5615 -
Journal of Clinical Microbiology Jun 1984A multicentric study of clinical Staphylococcus isolates was performed by seven operative units working in different areas of Italy. Over a 6-month period, a total of...
Identification, clinical distribution, and susceptibility to methicillin and 18 additional antibiotics of clinical Staphylococcus isolates: nationwide investigation in Italy.
A multicentric study of clinical Staphylococcus isolates was performed by seven operative units working in different areas of Italy. Over a 6-month period, a total of 3,226 staphylococci, isolated from in- and outpatients, were identified and tested for antimicrobial susceptibility by a protocol agreed upon by all units. On the basis of their bacteriolytic-activity patterns and other conventional tests, the isolates were identified by lyogroups , which closely correlate with human Staphylococcus species. Lyogroup I (Staphylococcus aureus) and lyogroup III (Staphylococcus capitis) were the most and the least frequently isolated staphylococci, respectively. Significant differences depending on strain origin from in- or outpatients were only observed with lyogroup IV (i.e., novobiocin- resistant staphylococci), whose isolation from outpatients was three times greater than from inpatients. Lyogroup I was predominant among isolates from most clinical sources. Lyogroup IV predominated in strains isolated from the urinary tract; lyogroup V (Staphylococcus epidermidis) predominated in strains from blood, cerebrospinal fluid, and indwelling artificial devices; and lyogroup VI ( Staphylococcus hominis, Staphylococcus haemolyticus, and Staphylococcus warneri ) predominated in strains from bile and the male genital tract. The incidence of methicillin resistance within the different lyogroups varied from unit to unit, suggesting epidemiological differences among different hospitals and different geographical areas. On the whole, methicillin resistance was more frequent in coagulase-negative staphylococci than in S. aureus and ranged from 19% for lyogroups I and III to 30% for lyogroup II (Staphylococcus simulans). Laboratory testing with 18 additional antibiotics suggested the occurrence of some specific differences in susceptibility among the different lyogroups . The rate of organisms resistant to the various antibiotics was greater among methicillin-resistant than among methicillin -susceptible staphylococci; particularly marked differences occurred with cephalosporins, rifampin, gentamicin, and tobramycin. The results suggested an increasing spread in Italy, during the last few years, of staphylococcal resistance to methicillin and to many other antibiotics. Some questions about the actual reliability of laboratory tests for the determination of staphylococcal susceptibility to methicillin and other beta-lactam antibiotics were raised by parallel test performances in which both unsupplemented and 5% NaCl-supplemented Mueller-Hinton agars were used. The presence of NaCl heightened, on the whole, the number of resistant strains detected; however, a few isolates resistant in the unsupplemented medium and susceptible in the salt-supplemented medium were also encountered. This was true not only for methicillin but also for all other beta-lactam antibiotics tested except cefamandole. With cefamandole, the presence of 5% NaCl reduced the number of resistant strains detected.
Topics: Anti-Bacterial Agents; Humans; Italy; Methicillin; Microbial Sensitivity Tests; Penicillin Resistance; Sodium Chloride; Species Specificity; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Staphylococcus epidermidis
PubMed: 6565709
DOI: 10.1128/jcm.19.6.838-843.1984 -
Journal of Dairy Science Dec 2012The aim of this study was to investigate whether the main coagulase-negative staphylococci (CNS) species involved in bovine intramammary infections (IMI) possess...
Characterization of coagulase-negative staphylococcus species from cows' milk and environment based on bap, icaA, and mecA genes and phenotypic susceptibility to antimicrobials and teat dips.
The aim of this study was to investigate whether the main coagulase-negative staphylococci (CNS) species involved in bovine intramammary infections (IMI) possess specific characteristics that promote colonization of the udder. Virulence markers associated with biofilm formation, antimicrobial resistance, and biocide tolerance were compared between typically contagious CNS species (Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus simulans) and those rarely causing IMI (Staphylococcus sciuri, Staphylococcus equorum, and others) to find possible associations with pathogenicity. Coagulase-negative staphylococci isolates (n=366) belonging to 22 different species were analyzed by PCR for the presence of the biofilm-associated genes bap and icaA, and the methicillin resistance gene mecA. A selection of 82 isolates was additionally tested for their susceptibility to 5 antibiotics and 2 commercial teat dip products. Minimum inhibitory concentrations of antimicrobials were determined by Etest (AB bioMérieux, Marcy l'Etoile, France), and a microdilution method was optimized to determine minimum biocidal concentrations of teat dips. The bap, icaA, and mecA genes were detected significantly more in isolates from CNS species typically living in the cows' environment than in isolates from IMI-causing species. Antimicrobial resistance was mainly against erythromycin (23%) or oxacillin (16%), and was detected more often in the environmental species. The isolates least susceptible to the teat dips belonged to the IMI-causing species Staph. chromogenes and Staph. simulans. We concluded that carriage of biofilm genes and antimicrobial resistance were not associated with the ability to colonize the mammary gland because free-living CNS species constituted a more significant reservoir of biofilm and resistance determinants than did IMI-causing species. In contrast, increased tolerance to biocides may favor the establishment of bovine IMI by some CNS species.
Topics: Animals; Anti-Infective Agents; Bacterial Proteins; Cattle; Drug Resistance, Bacterial; Female; Genes, Bacterial; Mammary Glands, Animal; Mastitis, Bovine; Microbial Sensitivity Tests; Milk; Phenotype; Staphylococcal Infections; Staphylococcus; Staphylococcus epidermidis; Staphylococcus haemolyticus
PubMed: 22999285
DOI: 10.3168/jds.2012-5400 -
Saudi Journal of Biological Sciences Mar 2018An extracellular lipase of a newly isolated strain ALA1 (SAL4) was purified from the optimized culture medium. The SAL4 specific activity determined at 60 °C and pH...
An extracellular lipase of a newly isolated strain ALA1 (SAL4) was purified from the optimized culture medium. The SAL4 specific activity determined at 60 °C and pH 12 by using olive oil emulsion or TC4, reached 7215 U/mg and 2484 U/mg, respectively. The 38 NH-terminal amino acid sequence of the purified enzyme starting with two extra amino acid residues (LK) was similar to known staphylococcal lipase sequences. This novel lipase maintained almost 100% and 75% of its full activity in a pH range of 4.0-12 after a 24 h incubation or after 0.5 h treatment at 70 °C, respectively. Interestingly, SAL4 displayed appreciable stability toward oxidizing agents, anionic and non-ionic surfactants in addition to its compatibility with several commercial detergents. Overall, these interesting characteristics make this new lipase promising for its application in detergent industry.
PubMed: 29686504
DOI: 10.1016/j.sjbs.2016.10.006 -
Veterinary Research Apr 2021Communications via quorum sensing (QS) between non-aureus staphylococci (NAS) and Staphylococcus (S.) aureus in the bovine mammary gland remains largely unexplored. We...
Communications via quorum sensing (QS) between non-aureus staphylococci (NAS) and Staphylococcus (S.) aureus in the bovine mammary gland remains largely unexplored. We determined whether 34 S. chromogenes, 11 S. epidermidis, and 14 S. simulans isolates originating from bovine milk samples and teat apices were able to regulate the QS of S. aureus, and if so, how in vitro growth inhibition of S. aureus by NAS, or NAS metabolites, or NAS cells themselves play a role in this process. In co-culture with S. aureus we observed that these 3 NAS species in general downregulated the expression of rnaIII, the effector molecule of the QS system, but this effect was more pronounced in S. chromogenes and S. simulans isolates than in S. epidermidis isolates. In vitro growth inhibition of S. aureus by NAS resulted in a small underestimation of the downregulating effect of NAS on rnaIII expression of S. aureus. Additionally, the culture supernatant of these NAS isolates and supernatant treated with proteinase K expressed greater regulatory activity over S. aureus virulence genes rnaIII, hla, and spa than washed NAS cells suspended in sterile water. These microbial interactions may influence S. aureus virulence and pathogenesis within the host. Isolation and identification of NAS metabolites affecting the QS system of S. aureus might help to develop alternative strategies for treatment and control of S. aureus mastitis.
Topics: Animals; Bacterial Proteins; Down-Regulation; Gene Expression Regulation, Bacterial; Mammary Glands, Animal; Milk; Quorum Sensing; Staphylococcus; Staphylococcus aureus; Trans-Activators
PubMed: 33926572
DOI: 10.1186/s13567-021-00933-x