SEARCH · PubMed Health

Results for “Staphylococcus”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,693 records · Page 94Linked to original sources

PubMed2003

Efficacy of intramammary tilmicosin and risk factors for cure of Staphylococcus aureus infection in the dry period.

The objective ofthis study was to evaluate the efficacy of intramammary tilmicosin, administered at drying-off, for eliminating Staphylococcus aureus infection, and to identify risk factors for S. aureus cure during the dry period. A total of 219 naturally infected cows, representing 308 quarters, were randomized to receive either one of two treatments at drying-off. Cows received either an intramammary infusion of 500 mg of benzathine cloxacillin, or a sterile solution containing 1,500 mg of tilmicosin. All cows had quarter milk samples taken aseptically three times before dry-off, and at wk 1, 2, and 4 of the subsequent lactation. Overall, 62% of cows and 67.5% of quarters infected with S. aureus cured during the dry period. The cure following administraton of tilmicosin was 67.3 and 72.5% for cows and quarters, respectively. By comparison, the cure achieved with cloxacillin was 56.9 and 62.9% of cows and quarters. Cows receiving tilmicosin were 2.1 times more likely to cure. The cure rate for cows decreased as the linear score on the last DHI test increased, and as the amount of S. aureus being shed increased. Quarters that cultured positive multiple times before drying-off were less likely to cure. Staphylococcus aureus infections located in front quarters of the udder were 2 times more likely to cure than those in hind quarters. Results of this study demonstrate that intramammary tilmicosin at drying-off is efficacious in curing existing S. aureus during the dry period. Risk factors associated with the cure of S. aureus were identified.

Animals↗

PubMed2003

Assessment of the opsonic activity of purified bovine sIgA following intramammary immunization of cows with Staphylococcus aureus.

The phagocytosis of Staphylococcus aureus by bovine polymorphonuclear neutrophils (PMN) requires the presence of antibodies. Among the major isotypes of bovine antibodies, IgG2 and IgM are considered opsonic for bovine PMN. However, the role of purified bovine secretory IgA (sIgA) as an opsonin has not been assessed. In the present study, IgG2 were obtained from serum and sIgA, IgG1, and IgM were purified from the colostrums of three cows intramammarily immunized with heat-killed Staphylococcus aureus. The Ig preparations were assayed for specific antibodies, and the opsonic capacity of every isotype was investigated. Despite the presence of antibodies, we observed no distinct chemiluminescence response of PMN stimulated with sIgA- or IgG1-opsonized S. aureus, whereas IgM or IgG2 bound to bacteria induced a marked chemiluminescence response. Moreover, the counting of internalized bacteria per PMN after phagocytosis revealed a low uptake of S. aureus opsonized with sIgA or IgG1, in contrast to IgM or IgG2, which triggered efficient ingestion of bacteria. Priming of neutrophils by TNF-alpha, IFN-gamma, or C5adesArg did not promote an oxidative burst or uptake of sIgA-opsonized S. aureus to a greater extent than with IgG1-opsonized bacteria. Furthermore, analysis of uningested bacteria by flow cytometry after incubation with PMN showed a preferential uptake of IgM-opsonized S. aureus by PMN and only few sIgA-positive stained bacteria were PMN-associated. These experiments indicate that sIgA, like IgG1 and unlike IgM or IgG2, could not be considered as a major opsonin for phagocytosis of S. aureus by bovine blood PMN.

Animals↗

PubMed2006

Invited Review: The role of cow, pathogen, and treatment regimen in the therapeutic success of bovine Staphylococcus aureus mastitis.

Staphylococcus aureus is an important cause of udder infections in dairy herds. Both lactational and dry cow therapy are part of Staph. aureus control programs. Reported cure rates for Staph. aureus mastitis vary considerably. The probability of cure depends on cow, pathogen, and treatment factors. Cure rates decrease with increasing age of the cow, increasing somatic cell count, increasing duration of infection, increasing bacterial colony counts in milk before treatment, and increasing number of quarters infected. Staphylococcus aureus mastitis in hind quarters has a low cure rate compared with front quarters. Antimicrobial treatment of intramammary infections with penicillin-resistant Staph. aureus strains results in a lower cure rate for treatment with either beta-lactam or non-beta-lactam antibiotics. Other strain-specific factors may affect the probability of cure but routine diagnostic methods for use in bacteriology laboratories or veterinary practices are not yet available. The most important treatment factor affecting cure is treatment duration. Increased duration of treatment is associated with increased chance of cure. Economically, extended treatment is not always justified, even when indirect effects of treatment such as prevention of contagious transmission are taken into consideration. Usefulness of treatment trials could be improved by standardization of case definitions, consideration of host and strain factors, and sufficient statistical power. Treatment of young animals with penicillin-sensitive Staph. aureus infections is often justified based on bacteriological cure and economic outcome, whereas treatment of older animals, chronic infections, or penicillin-resistant isolates should be discouraged.

Aging↗

PubMed1982

Feeding milk containing Staphylococcus aureus to calves.

Newborn calves from dams free of staphyloccocal udder infection were assigned to treatment groups in two experiments. Following colostrum feeding for 2 days, a culture of Staphylococcus aureus was added to pasteurized milk fed to one group twice weekly for a total of nine feedings. A control group received only pasteurized milk. Bull calves were in a short experiment to determine whether the organism was established in body tissues, and a second experiment was to determine the effect on incidence of mastitis at calving. No staphylococcus aureus was isolated from any body tissue or surfaces of bull calves necropsied at about 7 wk of age. Moreover, there was no difference in incidence of staphylococcal udder infection at first calving between heifers exposed to the organism as calves and controls. There appears little reason for concern about detrimental effects of feeding mastitic milk to calves under conditions where they are maintained in individual pens.

Animal Feed↗

PubMed1983

Evaluation of nine teat dip formulations under experimental challenge to staphylococcus aureus and streptococcus agalactiae.

Nine postmilking teat dips were evaluated by an experimental challenge model against either Staphylococcus aureus, Streptococcus agalactiae, or both. Formulations containing .9 and .6% sodium hypochlorite, 1% sodium dichloro-s-triazene-trione, .55% chlorhexidine gluconate, and .35% povidone iodine reduced incidence of Staphylococcus aureus infections 56.8, 28.3, 75.9, 92.5, and 77.9%. Incidence of infections with Streptococcus agalactiae was reduced 48.1 and 63.2% by 1.7 and 1% sodium dichloro-s-triazene-trione formulations. The 1% chlorhexidine gluconate and .35% povidone iodine products reduced Streptococcus agalactiae infections 71.0 and 67.0%. Three experimental 1% iodophor formulations reduced Streptococcus agalactiae infections 28.9, 44.8, and 50.7%. The experimental challenge model was refined further and provided an efficient method to determine efficacy of postmilking teat dips.

Administration, Topical↗

PubMed1984

Effect of dietary vitamin A on resistance to experimental Staphylococcus mastitis in mice.

Weanling mice (118) were fed a purified diet free of vitamin A for 3 wk and subsequently assigned to diets containing 10, 100 (4000 IU vitamin A/kg diet), or 300% of National Research Council recommended vitamin A. After 3 wk on the treatment diet all mice were bred and allowed to complete gestation. At 24 h postpartum, the left fourth abdominal mammary gland of each mouse was inoculated with Staphylococcus aureus (10(8) cells in .1 ml of saline/gland), and mammary gland infection was observed daily for 6 consecutive days. Liver vitamin A content was lowest in mice for 10% and highest for 300%. However, mice fed 10% showed normal growth and reproduction by small treatment differences in body weight changes, litter size at birth, and average pup weight. Mice fed 10 and 100% vitamin A showed more severe mammary gland inflammation after intramammary inoculation as opposed to mice fed 300%. Severity of mastitis in mice fed 100% vitamin A was similar to 10%. The number of mice classified as mastitic was also similar between 10 and 100% on days 1 and 2 postinoculation; however, on day 3 postinoculation mice fed 100% had a lower incidence of mastitis as opposed to 10%. Severity of mammary inflammation on days 4 through 6 were similar to those on day 3. Results showed a protective effect of dietary vitamin A supplementation against experimental Staphylococcus aureus mastitis in mice.

Analysis of Variance↗

PubMed1987

Effects of milk on activity of antimicrobics against Staphylococcus aureus isolated from bovine udders.

Addition of milk to Mueller-Hinton susceptibility test medium permitted measurement of milk effect on agar disc diffusion zone diameters obtained from Staphylococcus aureus herd isolates and stock strains. Milk reduced zone diameters for all antimicrobics tested when compared with zones obtained by standard methods. Antimicrobics most affected included novobiocin, streptomycin, gentamycin, tetracycline, and vancomycin. Growth curves of a reference strain of Staphylococcus aureus in Mueller-Hinton broth with and without milk indicated no effect on growth rate of the organism, suggesting the observed effect was due to the action of milk on the antimicrobics being tested. The described method offers a simple in vitro test for milk effects on antimicrobic activity.

Animals↗

PubMed1989

Isolation and identification of coagulase-negative Staphylococcus species from bovine body sites and streak canals of nulliparous heifers.

Heifers (n = 103) ranging in age from 1d to 2 yr were sampled to determine the coagulase-negative staphylococcal flora of haircoat, nares, vagina, teat skin, and streak canal. A total of 2706 staphylococal strains were identified from 3612 bacterial isolates. Other genera or groups identified included Bacillus, Micrococcus, Corynebacterium, and coliforms. Staphylococci were identified utilizing a simplified biochemical scheme. Staphylococcus xylosus, S. chromogenes, and S. warneri were the predominant species recovered from anatomic sites and streak canal. Staphylococcal strains identified from specific body sites (expressed as percentage of heifers harboring these species) were: nares 74% S. xylosus and 48% S. warneri; haircoat, 70% S. xylosus and 57% S. chromogenes; vagina, 60% S. chromogenes and 54% S. xylosus; teat skin 62% S. chromogenes and 61% S. warneri; streak canal 53% S. chromogenes, and 43% S. warneri. The prevalent staphylococcal strains identified differed from heifers in confined housing compared with heifers on pasture. Differences observed in distribution of Staphylococcus species among body sites, particularly those between teat skin and streak canal, suggest that establishment of staphylococcal microflora depends on the ability of a species to adapt to and colonize anatomic sites as well as on environmental conditions present.

Aging↗

PubMed1991

Staphylococcus aureus mastitis: pathogenesis and treatment with bovine interleukin-1 beta and interleukin-2.

Polymorphonuclear leukocytes play a central role in the pathogenesis of bovine mastitis. Intramammary challenge with Staphylococcus aureus was shown to induce both quantitative and qualitative changes in mammary gland polymorphonuclear leukocytes. Intramammary infusion of recombinant bovine interleukin-1 beta and interleukin-2 elicited a similar cellular response. Staphylococcus aureus, interleukin-1 beta, and interleukin-2 all increased the number of somatic cells after intramammary infusion and activated the inducible superoxide production in milk polymorphonuclear leukocytes. Interleukin-2 also activated phagocytosis of these cells, and their activation was maintained for 3 to 5 d after intramammary administration. Interleukin-1 beta and interleukin-2 were moderately effective in the therapy of experimental S. aureus mastitis. Approximately 54% of the glands treated with interleukin-1 beta responded to therapy by transiently clearing the milk of S. aureus, 30% of which relapsed, and a total of 38% of the treated glands remained cured. In contrast, 83% of glands treated with interleukin-1 beta responded to therapy, but 50% of these quarters relapsed. A total of 42% of the quarters treated with interleukin-1 beta remained cured. Homologous recombinant cytokines are effective immunomodulators that augment natural defensive mechanisms similar to the normal response to pathogens and may prove to be suitable alternatives to, or may be used in combination with, antibiotics as effective mastitis therapeutic agents.

Animals↗

PubMed1994

Adherence of Staphylococcus aureus to cultured bovine mammary epithelial cells.

Bovine mammary secretory cells, isolated at necropsy, were cultured in vitro and used as a model to study the mode of adherence of Staphylococcus aureus to mammary epithelium. Cultured cells were characterized by their morphology and physiology as secretory epithelial cells. Cells showed characteristic growth patterns when grown on polystyrene, fibronectin, laminin, collagen, and reconstituted basement membrane from the Engelbreth-Holm-Swarm murine sarcoma. Cells cultured on collagen formed confluent monolayers and were the most suitable for bacterial adherence studies. Cultured cells stained intensely for cytokeratin and for specific milk proteins, i.e., alpha-casein, beta-casein, alpha-lactalbumin, beta-lactoglobulin, and lactoferrin. The effect of frozen storage for 10 mo on cell viability or presence of milk proteins was minimal. Staphylococcus aureus showed large affinity for extracellular matrix components, i.e., fibronectin, laminin, and collagen. Adherence to confluent cell monolayers was minimal. In preconfluent cell monolayers, most S. aureus adhered more readily to the exposed matrix than to the epithelial cells. Overnight exposure to staphylococcal alpha-toxin greatly increased adherence of S. aureus to confluent monolayers. However, whether bacteria adhered to alpha-toxin damaged cells or to exposed matrix is not clear. Unencapsulated S. aureus adhered in larger numbers than did encapsulated S. aureus.

Animals↗

PubMed1999

Possible risk factors associated with penicillin-resistant strains of Staphylococcus aureus from bovine subclinical mastitis in early lactation.

A randomized controlled field study of selective dry cow therapy with 686 cows allocated to two control groups (sampling only or placebo) or two therapy groups was used to screen for possible factors associated with penicillin-resistant strains of Staphylococcus aureus after the dry period. Therapy was given either as a total dose of 400,000 IU of penicillin and 100 mg of neomycin per infected quarter as dry cow preparation or as a total dose of 1.2 million IU of penicillin and 1200 mg of dihydrostreptomycin per infected quarter as a lactation formula. Success cows had all quarters identified as being free of penicillin-resistant strains of Staphylococcus aureus both at calving and at 30 +/- 17 d after calving. Failure cows were those having penicillin-resistant strains of Staph. aureus in any quarter at both or one of these two samples after the dry period. Using logistic regression, four variables were found to be associated with penicillin-resistant strains of Staph. aureus after the dry period. These included the identification of penicillin-resistant strains of Staph. aureus either at 45 +/- 32 d before drying off and at drying off, treatment for acute clinical mastitis at least once during the previous lactation, the weighted SCC of all cows' milk by daily milk yield within the herd, and therapy in the lactation formula compared with the two control groups. Our finding that the use of lactation formula increases the risk of resistance development is contradictory to present arguments underlying Norwegian dry cow therapy strategy.

Animals↗

PubMed1999

Sensitivity of Staphylococcus aureus and Lactobacillus helveticus in ovine milk subjected to high hydrostatic pressure.

Ovine milk, standardized to 6% fat, was inoculated with Staphylococcus aureus CECT 534 and Lactobacillus helveticus CECT 414 at a concentration of 10(7) cfu/ml and treated by high hydrostatic pressure. Treatments consisted of combinations of pressure (200, 300, 400, 450, and 500 MPa), temperature (2, 10, 25, and 50 degrees C), and time (5, 10, and 15 min). Staphylococcus aureus was highly resistant to pressure; only pressurizations at 50 degrees C of 500 MPa for 15 min achieved reductions of > or = 7.3 log units. For L. helveticus, the number of surviving cells was reduced considerably at pressures of 400 MPa or more (up to 4.5 log units at 50 degrees C for 15 min), and pressure was more effective at low (2 and 10 degrees C) and moderately high (50 degrees C) temperatures than at room temperature (25 degrees C). Both species showed first-order kinetics of destruction in the range 0 to 60 min. The D values for S. aureus were 20 min (2 degrees C at 450 MPa) and 16.7 min (25 degrees C at 450 MPa), and D values for L. helveticus were 7.1 min (2 degrees C at 450 MPa) and 9.1 min (25 degrees C at 450 MPa). Lactobacillus helveticus showed higher rates of survival of pressure than those reported in previous studies for other Lactobacillus spp.

Animals↗

PubMed2004

Phase variation of biofilm formation in Staphylococcus aureus by IS 256 insertion and its impact on the capacity adhering to polyurethane surface.

While ica gene of Staphylococcus epidermidis is known to undergo phase variation by insertion of IS256, the phenomenon in Staphylococcus aureus has not been evaluated. Six biofilm-positive strains were tested for the presence of biofilm-negative phase-variant strains by Congo red agar test. For potential phase-variant strains, pulsed-field gel electrophoresis was done to exclude the possibility of contamination. To investigate the mechanism of the biofilm-negative phase variation, PCR for each ica genes were done. Changes of ica genes detected by PCR were confirmed by southern hybridization, and their nucleotides were analyzed by DNA sequencing. Influence of ica genes and biofilm formation on capacity for adherence to biomedical material was evaluated by comparing the ability of adhering to polyurethane surface among a biofilm-negative phase-variant strain and its parent strain. A biofilm-negative phase-variant S. aureus strain was detected from 6 strains tested. icaC gene of the phase-variant strain was found to be inactivated by insertion of additional gene segment, IS256. The biofilm-negative phase-variant strain showed lower adhering capacity to polyurethane than its parent strain. This study shows that phase variation of ica gene occurs in S. aureus by insertion of IS256 also, and this biofilm-negative phase variation reduces adhering capacity of the bacteria.

Bacterial Adhesion↗

PubMed1992

[Proposal for the nosocomial infection control of methicillin-resistant Staphylococcus aureus (MRSA)].

To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in hospital environments, quantitative isolation of MRSA from environmental and human specimens was performed. It was found that as many as 6 x 10(4) colony forming units (CFU)/100cm2 of MRSA and also methicillin-resistant coagulase-negative Staphylococcus (MRCNS) were isolated from 1) 25-100% of the bed-mattresses tested in 10 out of 11 (90%) hospitals, and also 2) bed sheets for patients, floors of patient wards, laundry, bath-room, toilet and laundry storage-room. And seven and eight palms of 20 patients were contaminated with MRCNS and MRSA, respectively, and MRCNS contamination was revealed in six of medical staffs. These results indicate that hospital environments, especially the mattresses and hospital floors are highly contaminated with MRCNS and MRSA, and sanitation and cleanliness of mattresses and floors are necessary to prevent the dissemination of both MRCNS and MRSA in hospital.

Cross Infection↗

PubMed2001

Vertebral osteomyelitis and prosthetic joint infection due to Staphylococcus simulans.

Staphylococcus simulans, a coagulase-negative staphylococcus, is a common animal pathogen that is rarely encountered in human infections. We describe a 70-year-old man who developed multifocal vertebral osteomyelitis and late prosthetic joint infection caused by this pathogen. The patient was a farmer who had daily contact with cows and drank unpasteurized milk, although the portal of the pathogen's entry remains speculative. Culture of the vertebral disk biopsy specimen and cultures during resection arthroplasty yielded S. simulans. A review of the literature suggests that S. simulans may be more virulent than other species of coagulase-negative staphylococci. Accurate identification of S. simulans isolates would facilitate studies to further define its pathogenic role in human infections.

Agriculture↗

PubMed2005

Detection of vancomycin resistant Staphylococcus aureus: a comparative study of three different phenotypic screening methods.

The objective of this study was to investigate screening methodologies, to detect Staphylococcus aureus strains with decreased susceptibility to vancomycin. Three methods were used to screen 160 Staphylococcus aureus clinical isolates along with ATCC quality control strains. Subsequently, MIC of all these 160 strains were determined by NCCLS methodology. The MIC of all the 160 clinical isolates was < or = 4 microg/mL and were classified as vancomycin susceptible by NCCLS criteria but 23 strains were positive by Hiramatshu method, two grew on MHA (5 microg/mL vancomycin) while CDC method correctly identified no vancomycin intermediate S.aureus (VISA) or vancomycin resistant S.aureus (VRSA) strains with reference to there MIC. CDC method was found to be the most appropriate screening methodology for detection of VISA or VRSA for diagnostic laboratories.

Bacteriological Techniques↗

PubMed2005

Survey of Staphylococcus isolates among hospital personnel, environment and their antibiogram with special emphasis on methicillin resistance.

The objective of this study was to find the prevalence of Staphylococcus spp. carriage among hospital personnel and hospital environment and their antibiogram with special emphasis on methicillin resistance. A total of 205 samples from hospital personnel and environment were collected from casualty, oncology and multidisciplinary cardiac unit ward of Kasturba Medical College Hospital, Manipal. Samples were collected using sterile cotton wool swabs and inoculated into brain heart infusion broth. Subcultures were done onto blood agar and MacConkey's agar. Isolates were identified by standard methods up to species level. Antimicrobial susceptibility test was performed according to standardized disc diffusion Kirby-Bauer method. Each of the isolates was screened for methicillin resistance using oxacillin disc on Mueller Hinton agar plate followed by MIC for methicillin and cefoxitin susceptibility test by disc diffusion method. Sixty five out of 205 strains (31.7%) were Staphylococcus spp. and all of them were coagulase negative. Most of the strains belonged to S.epidermidis 49.23% (32/65) followed by S. saprophyticus 26.15% (17/65). Maximum isolates of S.epidermidis were from anterior nares 28.12% (9/32 strains of S.epidermidis). Highest number of methicillin resistant coagulase negative strains (3/9, 33.33%) were isolated from stethoscope of multidisciplinary cardiac unit ward followed by carriers in the anterior nares (2/9, 22.22%). Methicillin resistant coagulase negative staphylococci are prevalent in anterior nares of hospital personnel and in the hospital environment thereby providing a definite source for hospital acquired infection. All isolates were sensitive to vancomycin, ciprofloxacin and amikacin.

Anti-Bacterial Agents↗

PubMedDate not supplied

Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in community-acquired primary pyoderma.

BACKGROUND: Although prevalence of MRSA strains is reported to be increasing, there are no studies of their prevalence in community-acquired primary pyodermas in western India. AIMS: This study aimed at determining the prevalence of MRSA infection in community-acquired primary pyodermas. METHODS: Open, prospective survey carried out in a tertiary care hospital in Mumbai. MATERIALS AND METHODS: Eighty-six patients with primary pyoderma, visiting the dermatology outpatient, were studied clinically and microbiologically. Sensitivity testing was done for vancomycin, sisomycin, gentamicin, framycetin, erythromycin, methicillin, cefazolin, cefuroxime, penicillin G and ciprofloxacin. Phage typing was done for MRSA positive strains. RESULTS: The culture positivity rate was 83.7%. Staphylococcus aureus was isolated in all cases except two. Barring one, all strains of Staphylococcus were sensitive to methicillin. CONCLUSIONS: Methicillin resistance is uncommon in community-acquired primary pyodermas in Mumbai. Treatment with antibacterials active against MRSA is probably unwarranted for community-acquired primary pyodermas.

Adolescent↗