scholarly journals Mercury resistance of Staphylococcus aureus

1970 ◽  
Vol 68 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Barbara M. Hall
Keyword(s):  
Staphylococcus Aureus ◽  
Nasal Carriage ◽  
Mercury Resistance ◽  
Development Of Resistance ◽  
Mercury Salts ◽  
Local Endemic ◽  
Resistant Strains ◽  
Endemic Strain ◽  
Made In

SummaryReasons for the accumulation of mercury-resistant strains of Staphylococcus aureus in hospital have been studied. A collection of paired strains, that is staphylococci similar in every respect except sensitivity to mercury salts, was made. Tests were made in an attempt to demonstrate a link between mercury resistance and some other factor which might aid survival, viz. resistance to drying and heat, production of bound coagulase, growth in the presence of sublethal amounts of tetracycline, survival in human blood at 37°C. and uptake by polymorphs at 30°0. and 37°C., development of resistance to antibiotics and competition in mixed cultures. It was not possible to demonstrate any consistent link between mercury resistance and any of these properties. Paper strips impregnated with the mercurial diuretic, Mersalyl, were shown to differentiate between mercury-resistant and -sensitive strains in vitro. Furthermore, development of resistance to mercury by passage in mercuric chloride-broth was demonstrated.It is proposed that mercury resistance has developed as a result of exposure to the mercury ion. Mercurial diuretics have been frequently used in medical and geriatric patients and it is among these that the higher carrier rates of mercury-resistant strains are found even when the local endemic strain is disregarded. In obstetric patients, where mercurials are seldom used, mercury-resistant strains are rare.Nasal carriage of factory workers exposed to mercury products showed that this group is likely to carry resistant or partially resistant strains.

scholarly journals Staphylococcus aureus Mutants Isolated via Exposure to Nonfluorinated Quinolones: Detection of Known and Unique Mutations

2001 ◽  
Vol 45 (12) ◽  
pp. 3422-3426 ◽  
Author(s):  
Siddhartha Roychoudhury ◽  
Tracy L. Twinem ◽  
Kelly M. Makin ◽  
Mark A. Nienaber ◽  
Chuiying Li ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sequence Analysis ◽  
Efflux Pump ◽  
Serial Passage ◽  
Efflux Pump Inhibitor ◽  
In Vitro Development ◽  
Development Of Resistance ◽  
High Level ◽  
Vitro Development

ABSTRACT The in vitro development of resistance to the new nonfluorinated quinolones (NFQs; PGE 9262932, PGE 4175997, and PGE 9509924) was investigated in Staphylococcus aureus. At concentrations two times the MIC, step 1 mutants were isolated more frequently with ciprofloxacin and trovafloxacin (9.1 × 10−8 and 5.7 × 10−9, respectively) than with the NFQs, gatifloxacin, or clinafloxacin (<5.7 × 10−10). Step 2 and step 3 mutants were selected via exposure of a step 1 mutant (selected with trovafloxacin) to four times the MICs of trovafloxacin and PGE 9262932. The step 1 mutant contained the known Ser80-Phe mutation in GrlA, and the step 2 and step 3 mutants contained the known Ser80-Phe and Ser84-Leu mutations in GrlA and GyrA, respectively. Compared to ciprofloxacin, the NFQs were 8-fold more potent against the parent and 16- to 128-fold more potent against the step 3 mutants. Mutants with high-level NFQ resistance (MIC, 32 μg/ml) were isolated by the spiral plater-based serial passage technique. DNA sequence analysis of three such mutants revealed the following mutations: (i) Ser84-Leu in GyrA and Glu84-Lys and His103-Tyr in GrlA; (ii) Ser-84Leu in GyrA, Ser52-Arg in GrlA, and Glu472-Val in GrlB; and (iii) Ser84-Leu in GyrA, Glu477-Val in GyrB, and Glu84-Lys and His103-Tyr in GrlA. Addition of the efflux pump inhibitor reserpine (10 μg/ml) resulted in 4- to 16-fold increases in the potencies of the NFQs against these mutants, whereas it resulted in 2-fold increases in the potencies of the NFQs against the parent.

scholarly journals Amoxicillin-Clavulanate Therapy Increases Childhood Nasal Colonization by Methicillin-Susceptible Staphylococcus aureus Strains Producing High Levels of Penicillinase

2004 ◽  
Vol 48 (12) ◽  
pp. 4618-4623 ◽  
Author(s):  
Didier Guillemot ◽  
Stephane Bonacorsi ◽  
John S. Blanchard ◽  
Philippe Weber ◽  
Sylvie Simon ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Drug Use ◽  
Odds Ratio ◽  
Selection Process ◽  
Nasal Carriage ◽  
Penicillin G ◽  
Nasal Colonization ◽  
Factors Associated ◽  
Amoxicillin Clavulanate ◽  
Resistant Strains

ABSTRACT We examined factors associated with penicillinase production by nasal carriage Staphylococcus aureus strains in 648 children aged 3 to 6 years attending 20 randomly sampled playschools. The children were prospectively monitored for drug use and medical events for 6 months and were then screened for S. aureus carriage. Isolates were tested for their susceptibility to penicillin G and methicillin, and penicillinase production by methicillin-susceptible, penicillin-resistant strains was quantified. S. aureus was isolated from 166 children (25.6%). Exposure to amoxicillin-clavulanate during the previous 3 months was associated with higher penicillinase production by penicillin-resistant, methicillin-susceptible strains (odds ratio, 3.6; P = 0.03). These results suggest that use of the amoxicillin-clavulanate combination could induce a herd selection process of S. aureus strains producing higher levels of penicillinase.

scholarly journals Introduction of the mec Element (Methicillin Resistance) into Staphylococcus aureus Alters In Vitro Functional Activities of Fibrinogen and Fibronectin Adhesins

1998 ◽  
Vol 42 (3) ◽  
pp. 564-570 ◽  
Author(s):  
Pierre E. Vaudaux ◽  
Vincenza Monzillo ◽  
Patrice Francois ◽  
Daniel P. Lew ◽  
Tim J. Foster ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Bacterial Colonization ◽  
Protein A ◽  
Methicillin Resistant ◽  
Functional Activities ◽  
Extracellular Matrix Components ◽  
Resistant Strains ◽  
The Impact

ABSTRACT Some methicillin-resistant strains of Staphylococcus aureus are defective in the production of major surface components such as protein A, clumping factor, or other important adhesins to extracellular matrix components which may play a role in bacterial colonization and infection. To evaluate the impact of methicillin resistance (mec) determinants on bacterial adhesion mediated by fibrinogen or fibronectin adhesins, we compared the in vitro attachment of two genetically distinct susceptible strains (NCTC8325 and Newman) to protein-coated surfaces with that of isogenic methicillin-resistant derivatives. All strains containing an intactmec element in their chromosomes were found to be defective in adhesion to fibrinogen and fibronectin immobilized on polymethylmethacrylate coverslips, regardless of the presence or absence of additional mutations in the femA,femB, or femC gene, known to decrease expression of methicillin resistance in S. aureus. Western ligand affinity blotting or immunoblotting of cell wall-associated adhesins revealed similar contents of fibrinogen- or fibronectin-binding proteins in methicillin-resistant strains compared to those of their methicillin-susceptible counterparts. In contrast to methicillin-resistant strains carrying a mec element in their genomes, methicillin-resistant strains constructed in vitro, by introducing the mecA gene on a plasmid, retained their adhesion phenotypes. In conclusion, the chromosomal insertion of themec element into genetically defined strains of S. aureus impairs the in vitro functional activities of fibrinogen or fibronectin adhesins without altering their production. This effect is unrelated to the activity of the mecA gene.

scholarly journals In VitroStudies Indicate a High Resistance Potential for the Lantibiotic Nisin in Staphylococcus aureus and Define a Genetic Basis for Nisin Resistance

2011 ◽  
Vol 55 (5) ◽  
pp. 2362-2368 ◽  
Author(s):  
Katy L. Blake ◽  
Chris P. Randall ◽  
Alex J. O'Neill
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Fold Increase ◽  
Peptide Antibiotics ◽  
Uncharacterized Protein ◽  
Content Type ◽  
Development Of Resistance ◽  
Genes Encoding ◽  
Bacterial Fitness

ABSTRACTLantibiotics such as nisin (NIS) are peptide antibiotics that may have a role in the chemotherapy of bacterial infections. A perceived benefit of lantibiotics for clinical use is their low propensity to select resistance, although detailed resistance studies with relevant bacterial pathogens are lacking. Here we examined the development of resistance to NIS inStaphylococcus aureus, establishing that mutants, including small-colony variants, exhibiting substantial (4- to 32-fold) reductions in NIS susceptibility could be selected readily. Comparative genome sequencing of a single NISrmutant exhibiting a 32-fold increase in NIS MIC revealed the presence of only two mutations, leading to the substitutions V229G in the purine operon repressor, PurR, and A208E in an uncharacterized protein encoded by SAOUHSC_02955. Independently selected NISrmutants also harbored mutations in the genes encoding these products. Reintroduction of these mutations into theS. aureuschromosome alone and in combination revealed that SAOUHSC_02955(A208E) made the primary contribution to the resistance phenotype, conferring up to a 16-fold decrease in NIS susceptibility. Bioinformatic analyses suggested that this gene encodes a sensor histidine kinase, leading us to designate it “nisin susceptibility-associated sensor (nsaS).” Doubling-time determinations and mixed-culture competition assays between NISrand NISsstrains indicated that NIS resistance had little impact on bacterial fitness, and resistance was stable in the absence of selection. The apparent ease with whichS. aureuscan develop and maintain NIS resistancein vitrosuggests that resistance to NIS and other lantibiotics with similar modes of action would arise in the clinic if these agents are employed as chemotherapeutic drugs.

scholarly journals Clinical and Bacteriological Aspects of Impetigo Contagiosa

1955 ◽  
Vol 53 (4) ◽  
pp. 495-508 ◽  
Author(s):  
George I. Barrow
Keyword(s):  
Staphylococcus Aureus ◽  
Special Reference ◽  
Streptococcus Pyogenes ◽  
Phage Type ◽  
Nasal Carriage ◽  
Control Groups ◽  
Staph Aureus ◽  
Impetigo Contagiosa ◽  
Resistant Strains

Summary1. The results of an investigation into the clinical, epidemiological and bacteriological features of impetigo contagiosa, with special reference to the type identification of staphylococci and streptococci, are reported and discussed.2. Of 106 impetigo cases studied, Staphylococcus aureus was isolated alone from 86 lesions (81 %), Streptococcus pyogenes alone from 6 (5·6 %), and a mixed growth of Staph. aureus and haemolytic streptococci in 14 instances (13·2 %).3. Of the 100 strains of Staph. aureus isolated from impetigo lesions, 63 were identical in phage type (‘type 71’), and a further 17 were closely related (‘weak 71’).4. Only one representative of ‘type 71’, and 9 of ‘weak 71’, were obtained from 164 strains of Staph. aureus from 200 persons in three control groups.5. Of 90 strains of Staph. aureus from impetigo lesions, 64 (71 %) were resistant to penicillin. Of these penicillin-resistant strains, 54 (84 %) were of ‘type 71’, or close variants.6. Strep, pyogenes was probably causative in at least 6 of the 18 patients yielding this organism from lesions; it was presumed to be a secondary invader in the remainder.7. It is doubtful if nasal carriage is of importance in the epidemiology of impetigo.8. It is concluded that there is a specific ‘type’ of staphylococcus associated with this form of impetigo.

scholarly journals Bacterial and Host Factors Implicated in Nasal Carriage of Methicillin-Resistant Staphylococcus aureus in Mice

2005 ◽  
Vol 73 (3) ◽  
pp. 1847-1851 ◽  
Author(s):  
Bruno González-Zorn ◽  
Jose P. M. Senna ◽  
Laurence Fiette ◽  
Spencer Shorte ◽  
Aurélie Testard ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Nasal Carriage ◽  
Transmembrane Conductance Regulator ◽  
Toll Like Receptor ◽  
Transmembrane Conductance ◽  
Methicillin Resistant ◽  
Toll Like Receptor 2 ◽  
Resistant Strains ◽  
Cystic Fibrosis Transmembrane ◽  
Deficient Mice

ABSTRACT Nasal carriage is a major risk factor for Staphylococcus aureus infection, especially for methicillin-resistant strains (MRSA). Using a mouse model of nasal carriage, we have compared several S. aureus strains and demonstrated increased colonization levels by MRSA in cystic fibrosis transmembrane conductance regulator-deficient mice and Toll-like receptor 2 (TLR2)-deficient mice but not TLR4-deficient mice.

scholarly journals In Vitro Activity of the Quinolone WCK 771 against Recent U.S. Hospital and Community-Acquired Staphylococcus aureus Pathogens with Various Resistance Types

2008 ◽  
Vol 53 (2) ◽  
pp. 811-813 ◽  
Author(s):  
Sachin S. Bhagwat ◽  
Pamela McGhee ◽  
Klaudia Kosowska-Shick ◽  
Mahesh V. Patel ◽  
Peter C. Appelbaum
Keyword(s):  
Staphylococcus Aureus ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Glycopeptide Resistance ◽  
Resistant Strains

ABSTRACT WCK 771 demonstrated MIC50 and MIC90s of 0.03 and 1 μg/ml, respectively, against 297 recent U.S. community-acquired and hospital strains of Staphylococcus aureus, irrespective of quinolone or glycopeptide resistance. Against quinolone-resistant strains, MIC90s of WCK 771 and moxifloxacin were 1 and 16 μg/ml, respectively.

scholarly journals Effect of Naseptin cream prophylaxis on staphylococcal infection in adult surgical wards and infant nurseries

1962 ◽  
Vol 60 (2) ◽  
pp. 209-215 ◽  
Author(s):  
E. Joan Stokes ◽  
Shelagh E. Milne
Keyword(s):  
Wound Infection ◽  
Marked Effect ◽  
Controlled Trial ◽  
Nasal Carriage ◽  
Staphylococcal Infection ◽  
Antibiotic Resistant ◽  
Resistant Strains ◽  
Made In

A controlled trial of Naseptin cream, as an anti-staphylococcaiprophylactic, made in two adult wards, showed the cream to be effective in reducing nasal carriage, including antibiotic resistant strains. There was no marked effect on wound infection.A controlled trial of Naseptin cream and Sterzac powder prophylactically in maternity nurseries was found to be effective in reducing nasal carriage and infection.These findings are discussed, and recommendations on the use of Naseptin cream as a prophylactic are made.

scholarly journals Missense Mutations in PBP2A Affecting Ceftaroline Susceptibility Detected in Epidemic Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Clonotypes ST228 and ST247 in Western Switzerland Archived since 1998

2015 ◽  
Vol 59 (4) ◽  
pp. 1922-1930 ◽  
Author(s):  
William L. Kelley ◽  
Ambre Jousselin ◽  
Christine Barras ◽  
Emmanuelle Lelong ◽  
Adriana Renzoni
Keyword(s):  
Staphylococcus Aureus ◽  
University Hospital ◽  
Surveillance Program ◽  
Missense Mutations ◽  
Unknown Parameters ◽  
Methicillin Resistant ◽  
Content Type ◽  
Resistant Strains ◽  
Mrsa Strains

ABSTRACTThe development and maintenance of an arsenal of antibiotics is a major health care challenge. Ceftaroline is a new cephalosporin with activity against methicillin-resistantStaphylococcus aureus(MRSA); however, no reports concerning MRSA ceftaroline susceptibility have been reported in Switzerland. We tested thein vitroactivity of ceftaroline against an archived set of 60 MRSA strains from the University Hospital of Geneva collected from 1994 to 2003. Our results surprisingly revealed ceftaroline-resistant strains (MIC, >1 μg/ml in 40/60 strains; EUCAST breakpoints, susceptible [S], ≤1 μg/ml; resistant [R], >1 μg/ml) were present from 1998 to 2003. The detected resistant strains predominantly belonged to sequence type 228 (ST228) (South German clonotype) but also to ST247 (Iberian clonotype). A sequence analysis of these strains revealed missense mutations in the penicillin-binding protein 2A (PBP2A) allosteric domain (N146K or E239K and N146K-E150K-G246E). The majority of our ST228 PBP2A mutations (N146K or E150K) were distinct from ST228 PBP2A allosteric domain mutations (primarily E239K) recently described for MRSA strains collected in Thailand and Spain during the 2010 Assessing Worldwide Antimicrobial Resistance Evaluation (AWARE) global surveillance program. We also found that similar allosteric domain PBP2A mutations (N146K) correlated with ceftaroline resistance in an independent external ST228 MRSA set obtained from the nearby University Hospital of Lausanne, Lausanne, Switzerland, collected from 2003 to 2008. Thus, ceftaroline resistance was observed in our archived strains (including two examples of an MIC of 4 µg/ml for the Iberian ST247 clonotype with the triple mutation N146K/E150K/G246E), at least as far back as 1998, considerably predating the commercial introduction of ceftaroline. Our results reinforce the notion that unknown parameters can potentially exert selective pressure on PBP2A that can subsequently modulate ceftaroline resistance.

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