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PubMed2004

Comparative evaluation of coagulase-negative staphylococci (CoNS) adherence to acrylic by a static method and a parallel-plate flow dynamic method.

The main goal of this work was to evaluate the adhesion to acrylic of several clinical strains of Staphylococcus epidermidis and Staphylococcus haemolyticus using both static and dynamic adhesion methods, and to compare the results obtained with these two methods. Adhesion was evaluated using the static slide method with different washing procedures, and the parallel plate flow chamber method. The extent of S. epidermidis adhesion, assessed by both methods, was greater than that of S. haemolyticus. The number of bacteria which adhered using the static method was lower than that using the dynamic method. It was found that the simple static method, when performed with an accurate washing procedure, can be as effective as the dynamic flow method for assessing differences in the adherence capacity of strains. Although the dynamic flow method yielded more overall information, its greater complexity and cost may not always justify its use for certain experimental comparisons. This investigation has shown that simple static adhesion methods, when performed accurately, can be used to evaluate differences in adhesion capacity.

Acrylates↗

PubMed2004

Differential regulation of Th1/Th2 in relevant tissues for sepsis pathogenesis with a Limulus anti-LPS factor-derived peptide increases survival in Gram-positive sepsis.

Severe sepsis and septic shock are important causes of death in intensive care units. Although Gram-negative infections were predominant in the 1960s, Gram-positive infections have increased in the past two decades and now account for about half of the cases of severe sepsis. In this study, we examined the effect of a Limulus anti-LPS factor (LALF)-derived peptide on lung and liver Th1/Th2 cytokine mRNA levels during a Gram-positive sepsis. We also examined the morphopathological changes observed in these organs during the disease. Mice challenged with a high dose of Staphylococcus haemolyticus showed severe damage in lung. In contrast, the liver of challenged mice showed an accumulation of bacterial particles in the sinusoids, associated with a severe inflammatory response due to high levels of tissue mRNA proinflammatory cytokines. Treatment with the peptide LALF(32-51) ameliorated the sepsis-induced effects in the lung and liver and increased the survival of mice in a dose- and time-dependent manner. Pretreatment with the peptide LALF(32-51) differentially regulates TNF-alpha, IFN-gamma, IL-12p40, IL-2 and IL-10 mRNA levels in lung and liver of peptide-treated mice, and limits the systemic inflammatory response. These findings support for the first time the effectiveness of an LALF-derived peptide in the treatment of a Gram-positive sepsis. Modulation of the Th1/Th2 pattern in tissues relevant for sepsis correlates with an improved outcome of the disease as denoted by increased survival.

Animals↗

PubMed2005

Comparative assessment of antibiotic susceptibility of coagulase-negative staphylococci in biofilm versus planktonic culture as assessed by bacterial enumeration or rapid XTT colorimetry.

OBJECTIVES: To quantitatively compare the antibiotic susceptibility of biofilms formed by the coagulase-negative staphylococci (CoNS) Staphylococcus epidermidis and Staphylococcus haemolyticus with the susceptibility of planktonic cultures. METHODS: Several CoNS strains were grown planktonically or as biofilms to determine the effect of the mode of growth on the level of susceptibility to antibiotics with different mechanisms of action. The utility of a new, rapid colorimetric method that is based on the reduction of a tetrazolium salt (XTT) to measure cell viability was tested by comparison with standard bacterial enumeration techniques. A 6 h kinetic study was performed using dicloxacillin, cefazolin, vancomycin, tetracycline and rifampicin at the peak serum concentration of each antibiotic. RESULTS: In planktonic cells, inhibitors of cell wall synthesis were highly effective over a 3 h period. Biofilms were much less susceptible than planktonic cultures to all antibiotics tested, particularly inhibitors of cell wall synthesis. The susceptibility to inhibitors of protein and RNA synthesis was affected by the biofilm phenotype to a lesser degree. Standard bacterial enumeration techniques and the XTT method produced equivalent results both in biofilms and planktonic assays. CONCLUSIONS: This study provides a more accurate comparison between the antibiotic susceptibilities of planktonic versus biofilm populations, because the cell densities in the two populations were similar and because we measured the concentration required to inhibit bacterial metabolism rather than to eradicate the entire bacterial population. While the biofilm phenotype is highly resistant to antibiotics that target cell wall synthesis, it is fairly susceptible to antibiotics that target RNA and protein synthesis.

Anti-Bacterial Agents↗

PubMed1993

A comparative study on growth in soft-agar, adherence to glass and haemolysis types of coagulase-negative staphylococci.

Growth properties of coagulase-negative staphylococci in the presence and in the absence of human and rabbit serum in soft-agar prepared in modified Staphylococcus 110 broth were studied. The adherent growth was examined in modified Staphylococcus 110 broth and 1% glucose-meat broth. Of 100 strains examined 69% exhibited diffuse, 18% compact, 7% transient and 6% mixed growth. Compact type colonies were mainly characteristic of Staphylococcus haemolyticus strains. The presence of serum failed to influence the types of colony morphology in any of the strains. Sixty-three percent of the strains showed adherent growth; none of the S. haemolyticus strains produced adherent growth. The glucose-meat broth, unlike modified Staphylococcus 110 broth, was suitable to study adherence. The coincidence of the compact colony morphology in soft-agar and the absence of adherent growth seems to be a taxonomic sign for the species S. haemolyticus and differentiate it from the species Staphylococcus epidermidis.

Agar↗

PubMed2004

Prevalence of methicillin-resistant, coagulase-negative staphylococci in neonatal intensive care units: findings from a tertiary care hospital in India.

This study was undertaken to determine the antimicrobial resistance pattern and species of coagulase-negative staphylococci (CNS) isolated from the blood and skin of neonates with clinical suspicion of late-onset septicaemia (>72 h post-delivery) admitted to neonatal intensive care units, with particular reference to the phenotypic and genotypic expression of methicillin resistance. Blood culture specimens were collected by venipuncture from 660 such neonates in brain heart infusion broth. Skin swabs from axillae were obtained from 60 neonates and inoculated on mannitol salt agar. All CNS thus obtained were further identified and antibiotic sensitivity was performed according to NCCLS recommendations. PCR for the mecA gene was carried out on 54 randomly selected isolates. Staphylococcus haemolyticus was the commonest species (34 %) followed by Staphylococcus epidermidis (24 %) amongst blood isolates. All blood isolates were sensitive to glycopeptides. Resistance to penicillin and methicillin was 94 and 66 %, respectively. Similar biotypes and antimicrobial resistance patterns were observed in skin isolates. All phenotypically methicillin-resistant isolates had the mecA gene and two of the phenotypically methicillin-sensitive isolates were also positive for mecA. A PCR assay for detection of the mecA gene in CNS may be a beneficial adjunct to standard susceptibility testing for timely and reliable detection of methicillin resistance. Given the large number of methicillin-resistant CNS, inclusion of vancomycin in empiric therapy for neonates with late-onset septicaemia may be justified.

Anti-Bacterial Agents↗

PubMed1996

Aminoglycoside resistance among Danish blood culture isolates of coagulase-negative staphylococci.

A sample of 137 coagulase-negative staphylococci isolated from blood cultures in Denmark over a 4-month period during 1992-1993 were tested for aminoglycoside resistance and for the presence of aminoglycoside-modifying enzymes. This was done on the basis of minimum inhibitory concentrations (MICs) measured by agar dilution, inhibition zone diameter by disk diffusion, and DNA dot blot analysis. Using the National Committee for Clinical Laboratory Standards (NCCLS) MIC breakpoints, 5%, 46%, 57%, and 63% of the strains were resistant to netilmicin, amikacin, gentamicin and tobramycin, respectively. The large majority of resistant staphylococci strains produced the bifunctional AAC(6)-III+APH(2") enzyme. The presence of AAC(6)-III+APH(2") explains the high level of resistance to gentamicin, kanamycin and tobramycin. In contrast to our results. Staphylococcus haemolyticus strains are usually reported to be more resistant than Staphylococcus epidermidis strains.

Aminoglycosides↗

PubMed1991

Susceptibility of Staphylococcus species and subspecies to teicoplanin.

Twenty-four Staphylococcus species and their subspecies were examined for their susceptibilities to teicoplanin by disk diffusion (30-micrograms disk) and agar dilution for the determination of MICs. Moderately susceptible and resistant clinical strains were further tested for their susceptibilities to oxacillin and vancomycin. Teicoplanin resistance was not observed in the reference strains of the various Staphylococcus species isolated from healthy volunteers or animals. However, the novobiocin-resistant species Staphylococcus saprophyticus, Staphylococcus cohnii, Staphylococcus xylosus, Staphylococcus arlettae, Staphylococcus kloosii, and Staphylococcus gallinarum were less susceptible to teicoplanin (MIC, 2 to 8 micrograms/ml) than most of the novobiocin-susceptible species were (MIC, 0.5 to 4 micrograms/ml). Clinical isolates of coagulase-negative species were generally less susceptible to teicoplanin than were reference strains. Seven percent of the Staphylococcus epidermidis clinical strains were moderately susceptible (MIC, 16 micrograms/ml) to teicoplanin. Of these strains, 70% were oxacillin resistant. For Staphylococcus haemolyticus strains, 11% were resistant (MIC, greater than 16 micrograms/ml) and 21% were moderately susceptible to teicoplanin. Of these strains, 95% were oxacillin resistant, No strains of S. epidermidis or S. haemolyticus were intermediate or resistant to vancomycin. Teicoplanin appears to be less active in vitro against oxacillin-resistant S. haemolyticus. However, teicoplanin is an effective antimicrobial agent against many Staphylococcus species.

Animals↗

PubMed1992

Post-antibiotic effect of the new streptogramin RP 59500.

The post-antibiotic effect (PAE) of RP 59500, a new streptogramin antibiotic, was determined for Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Streptococcus pneumoniae, and Streptococcus pyogenes. A 30 min exposure of Staphylococcus aureus to 5 micrograms/ml of RP 59500 produced a PAE of 1.9-6.9 h, and a 60 min exposure of 2.5 micrograms/ml produced a PAE of 3.2-8 h. A 30 min exposure of 5 micrograms/ml of RP 59500 of coagulase-negative staphylococci produced a PAE of 2.5-7.5 h. PAEs of constitutively erythromycin-resistant staphylococcal isolates were shorter than were the PAEs of highly susceptible isolates. A 30 min exposure to 5 micrograms/ml of RP 59500 produced a PAE of 7.5-9.5 h for Streptococcus pneumoniae and a PAE of greater than 18 h for Streptococcus pyogenes. RP 59500 produced a longer PAE with Staphylococcus aureus than did vancomycin, oxacillin or erythromycin. These results suggest that RP 59500 may be administered less frequently than would be suggested by its half-life.

Clindamycin↗

PubMed1982

Species identification and susceptibility to 17 antibiotics of coagulase-negative staphylococci isolated from clinical specimens.

A total of 299 isolates of gram-positive, catalase-positive, coagulase-negative cocci were isolated from a variety of specimens collected from patients at a large university hospital, and 281 (94%) were identified as staphylococci by established methods. Using the scheme of Kloos and Schleifer, we determined the species of the coagulase-negative staphylococci. Staphylococcus epidermidis was the cause of all bacteremias and the most commonly isolated species from bone, joint, and wound infections. Staphylococcus haemolyticus was the second most common isolate from wound infections, and Staphylococcus saprophyticus was the most commonly isolated species from urinary tract infections. Antibiograms to 17 antimicrobial agents were performed by a microdilution technique, and the results revealed that S. epidermidis was resistant to a water spectrum of antimicrobial agents than the other species of staphylococci were.

Adolescent↗

PubMedDate not supplied

Occurrence of macrolide-lincosamide-streptogramin resistances among staphylococcal clinical isolates at a university medical center. Is false susceptibility to new macrolides and clindamycin a contemporary clinical and in vitro testing problem?

A total of 2189 staphylococcal strains at the University of Iowa Hospitals and Clinics (Iowa City, IA) were initially screened to determine the incidence of constitutive (29.8%) and potential inducible macrolide-lincosamide-streptogramin (MLS) resistance (11.3%). Staphylococcus haemolyticus and S. epidermidis (62.5% and 55.3%) showed the highest incidence of constitutive resistance. Staphylococcus hominis had the highest incidence of inducible resistance (40.6%), while S. aureus had the lowest rate for both resistance types. The overall ratio of constitutive-inducible MLS resistance was 4:1. Among strains initially speciated using the Vitek System GPI card, there was only a 69% species identification reproducibility, and 78% accuracy versus a reference identification method. A random sample of 105 Staphylococcus spp. isolates with discordant macrolide (erythromycin resistant) and lincosamide (clindamycin susceptible) susceptibility patterns were tested against 16 antimicrobial agents by using a reference broth microdilution method. All erythromycin-resistant Staphylococcus spp. were also resistant to other 14-member macrolides and azithromycin, while all organisms remained susceptible to clindamycin, rifampin, vancomycin, and the streptogramin compounds (RP59500 and virginiamycin). Resistance to teicoplanin was identified among some oxacillin-resistant S. haemolyticus strains. Of 105 isolates, 65 (62%) showed inducible MLS resistance, 28 (27%) were noninducible, and 12 (11%) were either fully susceptible or resistant to the MLS drugs (Vitek System interpretation errors). MLS disk induction tests revealed two inducible resistance phenotypes: ML and MLS. Staphylococcus aureus showed the highest inducible resistance rate at 95% with an MLS-predominant pattern. In contrast, endemic S. haemolyticus isolates did not demonstrate inducible resistance that is, efflux-mediated erythromycin resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1985

Comparison of bacteriostatic and bactericidal inhibitors of Neisseria gonorrhoeae growth produced in vitro by urogenital staphylococci.

Coagulase-negative staphylococci are known to produce bactericidal and bacteriostatic antigonococcal activities. Out of 12 staphylococci, Staphylococcus haemolyticus (four isolates) was identified as the principal source of bactericidal activity, whereas Staphylococcus epidermidis (six isolates) was primarily responsible for producing bacteriostatic activity. A comparison of the bacteriostatic substance produced by S. epidermidis isolate 66 with the bactericidal substance produced by S. haemolyticus isolate 7, which had been previously purified, showed that they were similar lipoproteins or lipid-associated proteins. However, these two inhibitors migrated differently under electrophoresis on agarose gel. The protein component of the bacteriostatic inhibitor was more difficult to separate from the lipid component when chromatographed on Ultrogel AcA 54 in the presence of urea (4 M) than the protein component of the bactericidal inhibitor. The protein component of both types of inhibitors was responsible for the antigonococcal activity and was dissociable into subunits of approximately 1,400 daltons. However, these protein components had different migration patterns on agarose gel. The bacteriostatic substance displayed a bactericidal effect when dissociated from its lipidic component suggesting that the lipids might play a role in the type of inhibitory activity produced. All of the bactericidal and bacteriostatic substances contained in the different crude preparations were antigenically related.

Animals↗

PubMed1986

Identification of coagulase-negative Staphylococci isolated from urinary tract infections.

Coagulase-negative Staphylococci isolated from urinary tract infections were identified using the API Staph-Ident System. Organisms were excluded if there was no sign of pyuria or if normal urethral flora was present in significant amounts. While Staphylococcus saprophyticus and Staphylococcus epidermidis accounted for 81% of the isolates from females, 87% of isolates from males were S. epidermidis, Staphylococcus warneri, or Staphylococcus haemolyticus. The females fell into two main age groups, those with infections due to S. saprophyticus (mean age 25 years) and those due to other Staphylococci (mean age 40-49 years). All males were in a single age group (mean age 70-74 years) irrespective of the infecting agent. In males, S. warneri was associated with cellular changes in the bladder. No similar association was apparent with the other organisms. The results suggest that, apart from S. saprophyticus, three species of Staphylococcus (S. epidermidis, S. haemolyticus, S. warneri) account for most urinary tract infections, irrespective of the sex of the patient.

Adult↗

PubMed1992

Colonization with coagulase-negative staphylococci in two neonatal units.

Episodes of septicaemia due to coagulase-negative staphylococci (CNS) were more frequent in a level III than in a level II neonatal unit in Stockholm, Sweden. Colonization with CNS during the first 2 weeks of life was investigated in 10 infants from each unit. As the use of antibiotics differed between the two units, the aim was to correlate colonization and antimicrobial resistance patterns to antibiotic usage. Antimicrobial susceptibility of CNS to isoxazolylpenicillins, co-trimoxazole, erythromycin, clindamycin, chloramphenicol and gentamicin was determined. Selected isolates were typed with restriction endonuclease analysis of plasmid DNA and of genomic DNA. Infants were frequently colonized with multiple strains and species of CNS, and transmission of strains from patient to patient occurred within the unit. Qualitative and quantitative differences in antibiotic use were not correlated with colonization. The prevalence of resistant isolates, mostly of Staphylococcus haemolyticus, was higher in the level II unit with lower use of antibiotics. Staphylococcus epidermidis, which is generally more virulent, prevailed in the level III unit, where there were more severely ill children and invasive procedures were more frequently performed.

Anti-Bacterial Agents↗

PubMed2005

Evaluation of six commercial identification kits for the identification of Staphylococcus aureus isolated from bovine mastitis.

AIMS: Comparison of six commercially available in human medicine well-established slide agglutination systems for the identification of Staphylococcus aureus. METHODS AND RESULTS: Slide agglutination tests were compared with the conventional tube coagulase test, biochemical identification and with the molecular identification by polymerase chain reaction (PCR) amplification of species-specific parts of the gene encoding the 23S RNA. Systems evaluated included Masta-Staph (Mast Diagnostics), Staphylase-Test (Oxoid), Staphytect-Plus (Oxoid), Staphyloslide Latex (Becton Dickinson), Slidex Staph Plus (bioMerieux) and Dry Spot Staphytect Plus (Oxoid). A total of 141 staphylococcal strains isolated from cases of bovine mastitis including 90 S. aureus, 14 Staphylococcus epidermidis, 10 Staphylococcus warneri, 13 Staphylococcus xylosus, 11 Staphylococcus haemolyticus and three other coagulase-negative staphylococci were tested with each method. Staphylococcus aureus strains were selected by macrorestriction analysis with pulsed field gel electrophoresis (PFGE). Only genetically unrelated strains were included in the study. The sensitivities and specificities of the test were as follows: Masta-Staph 86.7 and 90.1%, Staphylase-Test 78.4 and 85.1%, Staphytect-Plus 81.1 and 86.5%, Staphyloslide Latex 77.8 and 84.4%, Slidex Staph Plus 77.8 and 84.4%, Dry Spot Staphytect Plus 75.6 and 83.0%. CONCLUSIONS: The results of this evaluation suggest that the six slide agglutination methods tested can provide rapid identification of S. aureus also from bovine mastitis. The sensitivity and specificity seems to be less than those reported from human S. aureus isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: This is one of the first comparative reported investigations about the applicability of different commercially available slide agglutination tests for the detection of S. aureus from bovine mastitis using PFGE selected clinical isolates.

Animals↗

PubMedDate not supplied

[A molecular biology approach to the species identification of coagulase-negative staphylococci].

A 1.3 DNA fragment isolated from Staphylococcus haemolyticus strain DSM 20264 can be used as a specific probe for this species. 28 collection strains including type strains of 26 Staphylococcus species, as well as 135 clinical isolates representing 8 species, have been studied with this probe by the dot hybridization method. The probe has been found to hybridize with all 42 S. haemolyticus strains, but with none of 121 strains belonging to other Staphylococcus species.

Bacteriological Techniques↗

PubMed2006

Fusidic acid resistance, mediated by fusB, in bovine coagulase-negative staphylococci.

OBJECTIVES: The aim of this study was to determine the occurrence of fusidic acid resistance, mediated by the fusB gene, among coagulase-negative staphylococci (CoNS) isolated from bovine mastitis. METHODS: A total of 113 CoNS isolates were screened for susceptibility to fusidic acid by using a disc diffusion method. The fusB gene was detected by using PCR and subsequent DNA sequencing. The localization of fusB was determined by hybridization. RESULTS: The fusB gene was detected in 3 of 11 fusidic acid-resistant bovine CoNS isolates. The organization of the fusB downstream region on a 40 kb plasmid in a Staphylococcus haemolyticus isolate (288/96) was highly similar to the previously reported organization of fusB on plasmid pUB101 from a Staphylococcus aureus isolate of human origin. The fusB gene was chromosomally located in the remaining two isolates. CONCLUSIONS: Fusidic acid resistance mediated by fusB is not the dominant resistance mechanism in fusidic acid-resistant CoNS studied in this work. The similarity between the organization of the fusB downstream region in S. haemolyticus (isolate 288/96) and on plasmid pUB101 from an S. aureus isolate of human origin indicates a common ancestral origin of these genes.

Animals↗

PubMed1989

Bacterial contamination of intraocular lenses: the source of the bacteria.

In order to investigate potential sources for the bacterial contamination of intraocular lenses, specimens were taken for culture from a variety of sites. A swab from the lid margin, the operating room air, an intraocular lens which was allowed to rest on the eye, and the sodium hyaluronate were cultured during routine intercapsular lens implant surgery on 31 patients. Positive cultures were obtained from six intraocular lenses. Subtyping by three independent methods showed that isolates from five of these lenses were indistinguishable from bacteria cultured from the air. In the case of the sixth lens a bacterial isolate from the lid margin matched with that from the lens. Staphylococcus epidermidis was cultured from four lenses; Staphylococcus haemolyticus was also isolated from one of these four lenses and the remaining two lenses produced isolates of Staphylococcus aureus.

Air Microbiology↗

PubMed1991

Evaluation of the Staph-Zym system with staphylococci isolated from bovine intramammary infections.

A total of 148 staphylococci isolated from bovine intramammary infections were used to evaluate the Staph-Zym system (ROSCO, Taastrup, Denmark). The overall accuracy of the system was 91.9%. The system correctly identified all strains of Staphylococcus aureus, Staphylococcus simulans, and Staphylococcus xylosus and 95% of Staphylococcus intermedius strains. Of 33 Staphylococcus hyicus strains, 31 (93.9%) were classified correctly by the Staph-Zym system, as well as 8 (80%) of 10 Staphylococcus chromogenes strains. All 11 Staphylococcus epidermidis strains and the 1 Staphylococcus haemolyticus strain included in the study were identified, but the Staph-Zym system had difficulty distinguishing strains of Staphylococcus warneri and Staphylococcus hominis from other species in the S. epidermidis group. The Staph-Zym system correctly identified all six S. xylosus strains and two of three Staphyloccus sciuri strains. The Staph-Zym system was considered an acceptable alternative to conventional methods for identification of bovine mammary gland isolates.

Animals↗