Effect of butterfat on inhibition of Staphylococcus aureus by nisin

1974 ◽  
Vol 20 (9) ◽  
pp. 1257-1260 ◽  
Author(s):  
L. W. Jones
Keyword(s):  
Staphylococcus Aureus ◽  
Inhibitory Action ◽  
Brain Heart Infusion ◽  
Streptococcus Lactis ◽  
Control Growth ◽  
Whole Milk ◽  
Brain Heart Infusion Medium

Nisin in brain heart infusion medium (Difco) and Bacto-Staphylococcus medium 110 completely inhibited the growth of Staphylococcus aureus 196. This restraining action of nisin on S. aureus was not as effective in the presence of whole milk. This was especially noted when attempts were made to control growth of S. aureus in cheese made with starter inactivated by phage. Although nisin had some inhibitory action on S. aureus in cheese it was not equal to that exerted by an active Streptococcus lactis culture. Its presence failed to prevent production of enterotoxin A. A factor influencing the failure of nisin to control growth of S. aureus in cheese was the presence of butterfat which was shown to interfere with the action of nisin against the growth of S. aureus.

scholarly journals Screening for Intermediately Vancomycin-Susceptible and Vancomycin-Heteroresistant Staphylococcus aureus by Use of Vancomycin-Supplemented Brain Heart Infusion Agar Biplates: Defining Growth Interpretation Criteria Based on Gold Standard Confirmation

2015 ◽  
Vol 53 (11) ◽  
pp. 3543-3546 ◽  
Author(s):  
Riad Khatib ◽  
Kathleen Riederer ◽  
Mamta Sharma ◽  
Stephen Shemes ◽  
Sugantha P. Iyer ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Gold Standard ◽  
Population Analysis ◽  
Area Under The Curve ◽  
Brain Heart Infusion ◽  
Roc Curves ◽  
Clinical Samples ◽  
Content Type ◽  
Interpretation Criteria ◽  
Profile Area

BHI agars supplemented with vancomycin 4 (BHI-V4) and 3 (BHI-V3) mg/liter have been proposed for screening vancomycin intermediately susceptibleStaphylococcus aureus(VISA) and heteroresistant (hVISA) phenotypes, respectively, but growth interpretation criteria have not been established. We reviewed the growth results (CFU) during population analysis profile-area under the curve (PAP-AUC) of consecutive methicillin-resistantStaphylococcus aureus(MRSA) blood isolates, which were saved intermittently between 1996 and 2012. CFU counts on BHI-V4 and BHI-V3 plates were stratified according to PAP-AUC interpretive criteria: <0.90 (susceptible [S-MRSA]), 0.90 to 1.3 (hVISA), and >1.3 (VISA). CFU cutoffs that best predict VISA and hVISA were determined with the use of receiver operating characteristic (ROC) curves. Mu3, Mu50, and methicillin-susceptibleS. aureus(MSSA) controls were included. We also prospectively evaluated manufacturer-made BHI-V3/BHI-V4 biplates for screening of 2010-2012 isolates. The PAP-AUC of 616 clinical samples was consistent with S-MRSA, hVISA, and VISA in 550 (89.3%), 48 (7.8%), and 18 (2.9%) instances, respectively. For VISA screening on BHI-V4, a cutoff of 2 CFU/droplet provided 100% sensitivity and 97.7% specificity. To distinguish VISA from hVISA, a cutoff of 16 CFU provided 83.3% sensitivity and 94.7% specificity; the specificity was lowered to 89.5% with a 12-CFU cutoff. For detecting hVISA/VISA on BHI-V3, a 2-CFU/droplet cutoff provided 98.5% sensitivity and 93.8% specificity. These results suggest that 2-CFU/droplet cutoffs on BHI-V4 and BHI-V3 best approximate VISA and hVISA gold standard confirmation, respectively, with minimal overlap in samples with borderline PAP-AUC. Simultaneous screening for VISA/hVISA on manufacturer-made BHI-V4/BHI-V3 biplates is easy to standardize and may reduce the requirement for PAP-AUC confirmation.

scholarly journals The effect of immunoregulation of Streptococcus lactis L16 strain upon Staphylococcus aureus infection

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Maopeng Wang ◽  
Shengjie Gong ◽  
Shouwen Du ◽  
Yilong Zhu ◽  
Fengjun Rong ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Aureus Infection ◽  
Streptococcus Lactis

scholarly journals Prevalence of Methicillin-Resistant Staphylococcus aureus on Paper Currency Notes

2021 ◽  
pp. 25-32
Author(s):  
Rikhi Ram Marasini ◽  
Pratikshya Shrestha ◽  
Prabhat Dhakal ◽  
Sukra Raj Shrestha ◽  
Sirjana Adhikari ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Brain Heart Infusion ◽  
Biochemical Tests ◽  
Mannitol Salt Agar ◽  
Methicillin Resistant ◽  
Total Prevalence ◽  
Paper Currency ◽  
Antibiotic Susceptibility Test ◽  
Hygiene Measures

The main objective of this study was to determine the prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) in paper currency. The paper currencies in circulation in Pokhara Metropolitan City were inspected. Bills of various denominations (Rs 5, 10, 20, 50, 100, 500 and 1000) were collected from five different locations; namely Food and Vegetable Shop, Bus conductor, Hospital Pharmacy, Butcher Shop and Grocery Shop. Collected sample were cultured and incubated for 24 hours at 37 oC in Brain Heart Infusion (BHI) Broth. The inoculums were further cultured on Mannitol Salt Agar (MSA) and Blood Agar (BA) media to obtain colonies, which were examined and evaluated for various parameters like gram staining and biochemical tests for identification. Then, antibiotic susceptibility test of the isolates was performed using standard procedures. A total of 35 sample of paper currency were processed, all of which showed positive growth. Out of 86 total isolates, 21 (24.42%) were Staphylococcus aureus followed by Coagulase Negative Staphylococci 19 (22.09%), Diptheroids 14 (16.3%), Bacillus spp 13 (15.11%), Micrococci 9 (10.46%), Streptococcus pneumonia 4 (4.65%), Viridans Streptococcus 4 (4.65%) and Streptococcus pyogenes 2 (2.32%). The total prevalence of MRSA in this study was 7 (33.33%). Paper currency contaminated with MRSA poses a high threat to those handling the bills as well as the community. Thus, this study suggests proper hygiene measures to be adopted after handling of paper currency to minimize the risk of contamination and emergence of diseases.

scholarly journals Hidden reservoirs of pathogens in dental settings

2021 ◽  
Vol 17 (1) ◽  
pp. 73-79
Author(s):  
Silpi Chatterjee ◽  
Keyword(s):  
Staphylococcus Aureus ◽  
Mobile Phones ◽  
Nosocomial Infections ◽  
Bacterial Species ◽  
Brain Heart Infusion ◽  
Bacillus Species ◽  
Coagulase Negative Staphylococcus ◽  
Cross Contamination ◽  
Sterile Saline ◽  
Predominant Species

Nosocomial infections are a major concern to both clinicians and health care seekers. Investigations have suggested that laptops & mobile phones may contribute to cross-contamination and can serve as vehicles for infection transmission. Therefore, it is of interest to document the data on hidden reservoirs such as mobile phones and laptops of pathogens in dental settings at the Hazaribag college of dental sciences and Hospital, Jharkhand. The samples were collected from 25 laptops and 25 mobile phones from dentists working in a dental college in Hazaribag city. The samples were collected aseptically using sterile cotton swabs dipped in sterile saline by rotating the swabs on the keyboard surfaces of laptops and mobile phones, inoculated into Brain Heart Infusion broth, vortexed for 1 minute in Fischer Vortex Genie 2 on highest setting & streaked immediately on 5% sheep blood agar plates and were incubated at 370C for 24 hours aerobically. The isolates were identified based on the colony morphology, colony characteristics and biochemical reactions. The bacterial species isolated were Staphylococcus aureus, Coagulase negative Staphylococcus, Bacillus species, Enterococci, Micrococci, and Pseudomonas etc. Predominant species isolated was Staphylococcus aureus and least was Micrococci. Higher percentage of organisms was found at the Department of Periodontics, Endodontics and least was found in Department of Public Health Dentistry. The percentage and type of organism isolated from keyboards of laptops and mobile phones were similar. Thus, laptops and mobile phones act as vehicles for transfer of potential pathogens associated with dental hospitals. Disinfecting the hands prior to examination of patients and disinfection of laptops and mobiles with alcohol wipes should be done to prevent nosocomial infections.

scholarly journals Prevalence and Characterization of Heterogeneous Vancomycin-Intermediate Staphylococcus aureus Isolates from 14 Cities in China

2009 ◽  
Vol 53 (9) ◽  
pp. 3642-3649 ◽  
Author(s):  
Wenjia Sun ◽  
Hongbin Chen ◽  
Yudong Liu ◽  
Chunjiang Zhao ◽  
Wright W. Nichols ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Population Analysis ◽  
Screening Method ◽  
Estimation Method ◽  
Area Under The Curve ◽  
Brain Heart Infusion ◽  
Screening Tests ◽  
Screening Methods ◽  
Large Numbers ◽  
Screening Cascade

ABSTRACT The prevalence of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) among 1,012 vancomycin-susceptible methicillin (meticillin)-resistant S. aureus isolates collected from 14 cities in China from 2005 to 2007 was 13 to 16%, as determined by a combination of (i) measurement by the modified population analysis profile-area under the curve method (PAP-AUC) and (ii) estimation from the measured sensitivity and specificity of a screening method. Two hundred isolates from blood were chosen as a subset for measurement of the sensitivities and the specificities of several previously described screening methods by using the results of PAP-AUC as the reference. During this testing, one isolate was found to be a vancomycin-intermediate S. aureus (VISA) strain so was not used in the evaluation of the screening tests. Of the other 199 isolates, 26 (13.1%) were hVISA, as assessed by PAP-AUC. A screening cascade of culturing the isolates on brain heart infusion agar containing teicoplanin (5 mg/liter) and then subjecting the positive isolates to a macro-Etest method was applied to the 812 non-blood isolates, yielding 149 positive results. From these results and by adjusting for sensitivity (0.423) and specificity (0.861), the prevalence was estimated to be 15.7%. The precision of that estimate was assessed by reapplying the screening cascade to 120 randomly selected isolates from the 812 non-blood isolates and simultaneously determining their heterogeneous vancomycin-intermediate susceptibility status by PAP-AUC. Because PAP-AUC is impractical for use with large numbers of isolates, the screening-based estimation method is useful as a first approximation of the prevalence of hVISA. Of the 27 VISA or hVISA isolates from blood, 22.2% and 74.1% were staphylococcal chromosome cassette mec types II and III, respectively, while 77.8% and 22.2% were agr type 1 and agr type 2, respectively; the MIC ranges were 0.5 to 4 mg/liter for vancomycin and 0.25 to 1 mg/liter for daptomycin.

Characteristics of Enterotoxin H–Producing Staphylococcus aureus Isolated from Clinical Cases and Properties of the Enterotoxin Productivity

2008 ◽  
Vol 71 (9) ◽  
pp. 1855-1860 ◽  
Author(s):  
FUMIHIKO SAKAI ◽  
HIDESHI IHARA ◽  
KENJI AOYAMA ◽  
HIDEO IGARASHI ◽  
SHUICHI YANAHIRA ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Water Activity ◽  
Food Poisoning ◽  
Brain Heart Infusion ◽  
Enzyme Linked Immunosorbent Assay ◽  
Late Exponential Phase ◽  
Epidemiological Characteristic ◽  
Predominant Type ◽  
High Prevalence ◽  
The Relationship

Staphylococcal enterotoxin H (SEH) is predicted to be involved in staphylococcal food poisoning. To characterize SEH-producing Staphylococcus aureus isolates from staphylococcal food poisoning cases in Japan, we investigated the relationship between SEH production and coagulase serotype, which is an epidemiological marker, and compared the properties of SEH production with those of staphylococcal enterotoxins A (SEA) and B (SEB). SEH production was determined by a newly developed sandwich enzyme-linked immunosorbent assay. Eighty-six (59.7%) of 144 isolates from staphylococcal food poisoning cases produced SEH. Seventy-one of the SEH-producing isolates simultaneously produced SEA, SEB, or both. All SEH-producing isolates belonged to coagulase type VII, which was the predominant type, representing 99 (68.8%) of 144 isolates. The amount of SEH produced in brain heart infusion was almost the same as the amount of SEA and approximately 10-fold lower than that of SEB. SEH and SEA were produced mainly during the late exponential phase of growth, whereas SEB was produced mostly during the stationary phase. The production levels of SEH and SEA were gradually affected by decreases in water activity, but the production of SEB was greatly reduced under conditions of low water activity. These findings indicate that SEH-producing S. aureus isolates are of high prevalence in staphylococcal food poisoning cases. Given the unique epidemiological characteristic of these isolates, SEH and SEA probably are responsible for food poisoning.

scholarly journals TSST-1, enterotoxin and bacteriocin-like substance production by Staphylococcus aureus isolated from foods

2013 ◽  
Vol 65 (5) ◽  
pp. 1537-1544 ◽  
Author(s):  
S.A. Carvalho ◽  
L.S. Carmo ◽  
E.F. Abreu ◽  
R.S. Dias ◽  
A.C.M. Apolônio ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bovine Milk ◽  
Food Poisoning ◽  
Brain Heart Infusion ◽  
Food Samples ◽  
Antagonistic Activity ◽  
Toxic Shock ◽  
Toxic Shock Syndrome Toxin ◽  
Reference Strains ◽  
Infusion Agar

The production of Toxic Shock Syndrome Toxin-1 (TSST-1), enterotoxins and bacteriocin-like substances was evaluated in 95 strains of Staphylococcus aureus recovered from raw bovine milk (n=31) and from food samples involved in staphylococcal food poisoning (n=64). Enterotoxigenicity tests with the membrane over agar associated to optimal sensibility plate assays were performed and showed that 96.77% of strains recovered from milk and 95.31% from food samples produced enterotoxins A, B, C, D or TSST-1. Reference strains S. epidermidis, Bacillus cereus, Listeria monocytogenes, Lactobacillus casei, Pseudomonas aeruginosa, S. aureus, Salmonella Typhimurium, Escherichia coli, Enterococcus faecalis and Bacteroides fragilis were used as indicator bacteria in the antagonistic assays, the first five being sensitive to antagonistic substances. Brain heart infusion agar, in pH values ranging from 5.0 to 7.0 in aerobic atmosphere showed to be the optimum condition for antagonistic activity as evaluated with the best producer strains against the most sensitive indicator bacterium, L. monocytogenes. Sensitivity to enzymes confirmed the proteinaceous nature of these substances. Neither bacteriophage activity nor fatty acids were detected and the antagonistic activity was not due to residual chloroform. Results did not establish a positive correlation between the bacteriocinogenic profile and toxigenicity in the tested S. aureus strains.

scholarly journals Incidence and Characteristics of Vancomycin Nonsusceptible Strains of Methicillin-Resistant Staphylococcus aureus at Hershey Medical Center

2008 ◽  
Vol 52 (12) ◽  
pp. 4510-4513 ◽  
Author(s):  
Klaudia Kosowska-Shick ◽  
Lois M. Ednie ◽  
Pamela McGhee ◽  
Kathy Smith ◽  
Cynthia D. Todd ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
False Positive ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Medical Center ◽  
Screening Method ◽  
Brain Heart Infusion ◽  
Methicillin Resistant ◽  
Repeat Testing ◽  
False Positivity ◽  
Positive Results

ABSTRACT All 982 methicillin-resistant Staphylococcus aureus strains collected from August 2006 to December 2007 were tested for vancomycin susceptibility by using 3-μg/ml vancomycin brain heart infusion screening plates, a vancomycin Etest, and a vancomycin/teicoplanin macro Etest. Three vancomycin-intermediate Staphylococcus aureus (VISA) (0.3%) and two heterogeneous VISA (0.2%) isolates were identified. The screening method yielded 895 cases of ≤1 colony and 87 positive results (with growth of >1 colony after 48 h); further Etests showed 82/87 isolates with growth on screening plates to be false positive. Repeat testing showed a false-positivity rate of only 15 of the original 87 isolates by plate screening.

Growth of Staphylococcus aureus in Milks and Creams with Various Amounts of Milk Fat

1989 ◽  
Vol 52 (8) ◽  
pp. 540-543 ◽  
Author(s):  
MARGARET I. HALPIN-DOHNALEK ◽  
ELMER H. MARTH
Keyword(s):  
Staphylococcus Aureus ◽  
Milk Fat ◽  
Incubation Temperature ◽  
Skim Milk ◽  
Fold Increase ◽  
Fat Content ◽  
Strain Variation ◽  
High Fat ◽  
Whole Milk

Staphylococcus aureus strains 100-A, 196-E, 254, 473, 505, and 521 generally grew better in skim milk and whole milk (3.5% milk fat) than in light cream (18% milk fat) and heavy whipping cream (36% milk fat) at 25 and 37°C. S. aureus strains grew to greater than 106/ml from an inoculum of ca. 103/ml in skim and whole milk held at 37°C. From the same level of inoculum, strains grew to 106–107/ml in light cream held at 37°C. A 10 to 100-fold increase in population was observed for most strains in heavy whipping cream inoculated with ca. 104 S. aureus/ml and held at 37°C. Less than a 10-fold increase in population was noted for strain 254 in heavy whipping cream held at 37°C. When strains of S. aureus were inoculated into milks and creams and held at 25°C, populations of the pathogen increased approximately 100-fold in skim and whole milk and 10-fold or less in light cream and heavy whipping cream. S. aureus was enumerated using Chapman Stone, Mannitol Salt, Baird-Parker, and Vogel-Johnson agars; best results were obtained with Baird-Parker and Vogel-Johnson agars, particularly when high-fat fluid products were tested. Milk fat content, incubation temperature, and strain variation influenced the ability of S. aureus to grow in various dairy fluids.

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