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PubMedDate not supplied

[Resistance profiles of the various species of the genus Staphylococcus to 15 clinically-used antimicrobials].

A total of 78 strains of 11 species of Staphylococcus genus (29 S. aureus, 48 Staphylococcus coagulase-negative and 1 S. intermedius strain,) were studied in order to determine the resistance patterns to fifteen commonly used antimicrobial agents. Out of 48 Staphylococcus coagulase-negative strains studied, 8 (4/15 S. epidermidis, 1/10 S. hominis, 1/6 S. haemolyticus, 2/3 S. xylosus) showed resistance patterns similar to that of S. aureus strains against beta-lactam antibiotics, aminoglycosides, chloramphenicol and fosfomycin, and 10 exhibit beta-lactamase-activity. Although the 7 S. saprophyticus strains assayed were beta-lactamase-negative by the chromogenic cephalosporin method after induction, the penicillin G minimal inhibitory concentration values were slightly higher than those obtained with other beta-lactamase-negative species. The susceptibilities to erythromycin and clindamycin suggested that macrolides-lincosamides-streptogramin type B (MLS) resistance was present in a large number of Staphylococcus coagulase-negative strains. In all the Staphylococcus genus, the aminoglycosides resistance seems to be mediated by the same aminoglycosides modifying-enzymes. Vancomycin was very active against the 11 species assayed. Rifampicin was effective with all Staphylococcus coagulase-negative strains. The S. aureus rifampicin-resistant were also resistant to oxacillin, and variable against aminoglycosides, chloramphenicol, fosfomycin, erythromycin and clindamycin. Only 5 strains were resistant to trimethoprim-sulfamethoxazole (TMS), 1 S. aureus oxacillin-susceptible, 1 S. aureus oxacillin-resistant, 2 S. xylosus and 1 S. warneri strains.

Drug Resistance, Microbial↗

PubMed1980

Catheter sepsis due to Staphylococcus epidermidis during parenteral nutrition.

Staphylococcus epidermidis is a pathogenic organism with increasing importance in total parenteral nutrition therapy. Strict asepsis during catheter insertion prolongs the interval free from Staphylococcus epidermidis infection. Staphylococcus epidermidis colonizes the catheter after migrating from the skin. For protection, we advise a long subcutaneous tunnel for all catheters that are to be indwelling for longer than three weeks. Prompt recatheterization of a patient with Staphylococcus epidermidis sepsis can result in hematogenous seeding of the new catheter and persistence of the infection. Catheter related Staphylococcus epidermidis sepsis has subsided after catheter withdrawal, and there is no need for antibiotic therapy provided that other prosthetic materials are not placed in the vascular tree. Immunologic status of the patients is not related to the frequency or severity of Staphylococcus epidermidis infections, or both.

Adult↗

PubMed1993

[Detection of methicillin-resistant Staphylococcus aureus by in vitro enzymatic amplification of mecA and femA genes].

In the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection, rapid detection of MRSA is extremely important. The mecA gene codes the new drug resistant polypeptides called penicillin-binding protein 2a (PBP2a) or 2'(PBP2'), which mediates the clinically relevant resistance to all beta-lactam antibiotics. This gene could be beneficial in the detection of MRSA using the polymerase chain reaction (PCR). However, the identical mecA gene has been found in both coagulase-positive and coagulase-negative Staphylococcus with the appropriate methicillin-resistant phenotype. The second gene related to the expression of methicillin-resistance has been called femA. In this study, we amplified both mecA and femA genes by PCR in 97 strains and 32 clinical specimens. The mecA gene was positive in all 63(100%) MRSA strains and 2(6%) of the 34 methicillin-sensitive Staphylococcus aureus (MSSA) strains. Two strains with the methicillin-sensitive phenotype and the mecA gene resulted in methicillin-resistance when cultured on an agar plate containing 4.5% NaCl. The mecA gene was also present in all 10(100%) coagulase-negative Staphylococcus strains with the methicillin-resistant phenotype. The femA gene was positive in all 97(100%) MRSA and MSSA strains. On the other hand, the femA gene was absent from coagulase -negative Staphylococcus strains with the methicillin-resistant phenotype. Although the mechanism by which the product of femA gene influences the expression of methicillin-resistance is unknown, the gene appears to be restricted only in coagulase-positive Staphylococcus, regardless of methicillin-resistance. In conclusion, in vitro enzymatic amplification of both mecA and femA genes would lead to rapid and definite diagnosis of the MRSA infection.

Base Sequence↗

PubMed1993

Relation of cholesterol-stimulated Staphylococcus aureus growth to chronic blepharitis.

PURPOSE: Many types of chronic blepharitis have been believed to be primarily microbial in origin; however, it was proposed that differences and changes in lipid composition of meibomian secretion may be the initiating factor in some of these. It was recently reported that there are two subgroups of normals, those whose meibomian secretions contain high levels of cholesterol esters and those whose secretions contain very low levels of these esters. Thus, these subgroups of normals were defined on the basis of detailed lipid analyses of meibomian secretions from individuals showing no clinical signs of chronic blepharitis. All secretions from patients in the various disease groups contain high levels of these esters. Based on previous observations that in some chronic blepharitis disease groups certain Staphylococcus species were capable of hydrolyzing cholesterol esters, the authors tested the hypothesis that the resulting cholesterol might affect growth of Staphylococcus aureus. METHODS: Staphylococcus aureus growth stimulation in Mueller-Hinton broth by cholesterol was determined by colony forming units. Growth stimulation by cholesterol and other additives was also determined by the optical density 650 nm method. Statistical analyses included analysis of variance and the Student's t test. RESULTS: Cholesterol stimulated Staphylococcus aureus growth was significant during the first 24 hr period (20% increase at 25 microM cholesterol, P < 0.02), and for the total 48 hr period (40% increase at 400 microM cholesterol, P < 0.005) when compared to the respective control. Growth stimulation, determined by OD at 650 nm, in the presence of cholesterol was significantly greater (P < 0.02) than that in the presence of either sitosterol or cholestanol when the sterol concentration was 190 microM. CONCLUSION: These results suggest that the presence and hydrolysis of cholesterol esters of meibomian secretions may contribute to the proliferation of Staphylococcus spp, especially Staphylococcus aureus, observed in some chronic blepharitis disease groups.

Blepharitis↗

PubMed1996

Methicillin-resistant Staphylococcus aureus and Candida albicans on denture surfaces.

Infectious diseases caused by methicillin-resistant Staphylococcus aureus, MRSA, and Candida albicans are often serious in compromised hosts. We enumerated MRSA and C. albicans on denture surfaces and in saliva samples from 29 adults. Staphylococcus species, MRSA, and methicillin-resistant Staphylococcus epidermidis, MRSE, were detected on 17, 3, and 1 of the 29 denture surfaces, respectively. C. albicans were detected on 22 denture surfaces. All saliva samples from patients whose dentures carried Staphylococcus species and C. albicans were also found to contain both microorganisms. Adherence of isolated 3H labeled cells of MRSA and C. albicans to resin beads and saliva-coated resin beads was examined. Cells of both microorganisms adhered in significantly higher numbers to saliva-coated resin beads than to resin beads. The hydrophobicity of the MRSA isolated from denture surfaces varied from strain to strain; that of C. albicans strains was moderately high. The zeta potentials of MRSA isolates and of C. albicans isolates determined in KCI buffer were significantly low. The potential of the resin beads decreased after treatment with saliva. Two out of 5 MRSA strains were found to be inhibited in growth by oral Streptococcus, Actinomyces, and gram-negative bacterial strains, suggesting that some oral bacterial species play a role in inhibiting the colonization of Staphylococcus species. No isolates of C. albicans were inhibited in their growth by any of the oral bacteria tested. Isolates of MRSA and C. albicans coaggregated with Porphyromonas gingivalis and Fusobacterium nucleatum strains. Using denture cleaners every night for 2 weeks did not reduce numbers of Staphylococcus species or C. albicans organisms in saliva.

Actinomyces↗

PubMed2005

Trends and outcome of nosocomial and community-acquired bloodstream infections due to Staphylococcus aureus in Finland, 1995-2001.

In Finland, Staphylococcus aureus bloodstream infections are caused predominantly (>99%) by methicillin-sensitive strains. In this study, laboratory-based surveillance data on Staphylococcus aureus bloodstream infections occurring in Finland from 1995 to 2001 were analyzed. Preceding hospitalizations for all persons with Staphylococcus aureus bloodstream infections were obtained from the national hospital discharge registry, and data on outcome was obtained from the national population registry. An infection was defined as nosocomial when a positive blood culture was obtained more than 2 days after hospital admission or within 2 days of admission if there was a preceding hospital discharge within 7 days. A total of 5,045 cases were identified. The annual incidence of Staphylococcus aureus bloodstream infection rose by 55%, from 11 per 100,000 population in 1995 to 17 in 2001. The increase was detected in all adult age groups, though it was most distinct in patients >74 years of age. Nosocomial infections accounted for 51% of cases, a proportion that remained unchanged. The 28-day death-to-case ratio ranged from 1% in the age group 1-14 years to 33% in patients >74 years of age. The 28-day death-to-case ratios for nosocomial and community-acquired infections were 22% and 13%, respectively, and did not change over time. The increase in incidence among elderly persons resulted in an increase in the annual rate of mortality associated with Staphylococcus aureus bloodstream infections, from 2.6 to 4.2 deaths per 100,000 population per year. Staphylococcus aureus bloodstream infections are increasing in Finland, a country with a very low prevalence of methicillin resistance. While the increase may be due in part to increased reporting, it also reflects a growing population at risk, affected by such factors as high age and/or severe comorbidity.

Adolescent↗

PubMed2026

Multi-omics evidence reveals robust airborne-human resistome connectivity driven by high-risk ARGs and mediated by Staphylococcus.

Airborne microbiomes are considered an important source of human antimicrobial resistance (AMR) exposure, yet multi-omics evidence linking airborne and human nasal resistomes remains limited. Here, we integrated metagenomic sequencing and whole-genome sequencing of antibiotic-resistant Staphylococcus isolates to investigate the connectivity between air and human nasal resistomes in dairy farm environments. Metagenomic taxonomic profiling showed that Staphylococcus was prominent in total suspended particles (TSP) and consistently detected across all samples. Among environmental reservoirs, TSP resistomes exhibited the strongest similarity to human nasal resistomes. This connectivity was supported by multiple lines of evidence, including highly similar resistome profiles, extensive homologous antibiotic resistance gene (ARG) pairs, strain-level similarity of resistant Staphylococcus isolates, and conserved mobile ARG genetic contexts. Notably, this connectivity was primarily driven by high-risk ARGs, while Staphylococcus was frequently associated with mobile ARGs and represented the only shared pathogenic genomes carrying both ARGs and virulence factor genes between airborne and nasal samples. Although lower ARG diversity, nasal resistomes exhibited higher ARG burden, risk scores, antibiotic-resistant bacterial genome abundance, and prevalence of resistant Staphylococcus. Occupational exposure further increased total and high-risk ARG burdens among farm workers. Together, these findings indicate that TSP can serve as an important route of occupational AMR exposure, with high-risk ARGs and Staphylococcus contributing to connectivity between airborne and nasal resistomes. Incorporating the host microbiome may therefore provide a more complete assessment of human-associated AMR exposure within a One Health framework.

Airborneresistome↗

PubMed2000

A high incidence of Staphylococcus aureus colonization in the external eyes of patients with atopic dermatitis.

OBJECTIVE: To determine the frequency distribution of bacteria on the external surface of eyes of patients with atopic dermatitis (AD) and to investigate the relationship between the frequency of bacterial colonization and the grade of atopy or ocular diseases associated with AD. DESIGN: Comparative cross-sectional study. PARTICIPANTS: Thirty-six AD patients (mean age, 24.5 years) and 16 nonatopic, age-matched control participants (mean age, 25.5 years). INTERVENTION: The eyelid margins and conjunctival sacs were scraped with sterile swabs. These samples were inoculated into aerobic and anaerobic culture media. MAIN OUTCOME MEASURES: The frequency distribution of bacteria isolated from the eyelid margins and conjunctival sacs. RESULTS: Bacteria isolated from AD patients were: Staphylococcus aureus in 21 of 36 patients (including methicillin-resistant Staphylococcus aureus in two patients); Staphylococcus epidermidis in two patients (including methicillin-resistant Staphylococcus epidermidis in one patient); other coagulase-negative Staphylococcus in six patients;alpha-streptococcus in three patients; Corynebacterium species in three patients; Neisseria species in two patients; and Propionibacterium acnes in one patient. From the nonatopic control participants, we isolated S. aureus in one patient, S. epidermidis in two patients and alpha-streptococcus in one patient. S. aureus was isolated from 67% of the AD patients, and any type of bacteria was isolated from 86% of the patients. These rates were significantly higher than those of nonatopic control participants (6% S. aureus and 25% any bacteria). There was no significant relationship between the frequency distribution of bacteria and the grade of atopy or associated ocular diseases. CONCLUSIONS: High rates of bacterial colonization, especially S. aureus, were found in the conjunctival sacs and eyelid margins of AD patients. In case management of AD patients, this unique distribution of bacteria must be carefully considered.

Adolescent↗

PubMed1961

The site of action of the Staphylococcus alpha toxin.

The present study concerns the site of action of the staphylococcus alpha toxin. This powerful necrotizing agent produced by pathogenic strains of staphylococcus is very probably important in the pathogenesis of localized staphylococcus disease and in the shock-like picture sometimes associated with staphylococcus septicemia. Our previous studies had suggested that the toxin has a selective effect on vascular smooth muscle. In investigating this problem further, the following observations were made. 1. The toxin produces an immediate hyperperistalsis and sustained increase in intraluminal tension progressing ultimately to atony and flaccid paralysis in the isolated smooth muscle preparation. 2. The addition of specific antitoxin prior to exposure to toxin prevents this reaction. However, when antitoxin is added after the toxin, no ameliorating effect is seen. 3. The toxin is rapidly and irreversibly bound to its substrate since washing the bowel segment 30 seconds after exposure to toxin fails to change the course of the reaction. 4. Vena caval segments exposed to toxin exhibit a similar initial rise in intraluminal tension followed by flaccid paralysis at which point they no longer respond to epinephrine stimulation. 5. When the toxin is infiltrated in the neighborhood of muscular blood vessels in the living rabbit selective necrosis of smooth muscle cells of the vessel walls is seen. 6. The selective effect on smooth muscle is emphasized by the failure of the toxin to affect the contractility of skeletal and cardiac muscle. 7. Perfusion of the isolated kidney and heart produces an increased resistance to flow after toxin is added to the perfusate. 8. Epithelial cells and fibroblasts in tissue culture exposed to high concentration of toxin for 2 hours are unaffected in their ability to recover and metabolise. This is in marked contrast to the effect on the smooth muscle preparation. The probability that the toxic effect on smooth muscle cells explains some of the local and systemic effects of staphylococcus infection is discussed.

Animals↗

PubMed1979

Haemagglutination by Staphylococcus saprophyticus and other staphylococcal species.

Staphylococcus saprophyticus was found to differ from Staphylococcus epidermidis and Staphylococcus aureus by its ability to agglutinate sheep erythrocytes. On testing 30 strains of each species, 28 strains of S. saprophyticus and one strain each of the other two species, caused agglutination. Twenty-eight of 30 strains of staphylococcus cohnii and Staphylococcus xylosis failed to cause haemagglutination. The haemagglutinating activity of S. saprophyticus, when using a 10 per cent bacterial suspension was demonstrated in dilutions of 1:2-1:32. It was reduced twofold, at most, when exposing the bacteria to 56 degrees C for 30 minutes, while no agglutination could be demonstrated after treatment for 10 minutes at 86 degrees C. No haemagglutination could be demonstrated after treatment of the bacteria with 5 per cent solution of trypsin. Treatment of S. saprophyticus with 0.1 M EDTA did not affect the haemagglutinating activity, whereas exposure of the bacteria to 10 per cent trichloroacetic acid reduced the activity. The haemagglutination was D-mannose-resistant, and it was inhibited by homologous rabbit antiserum. The agglutinates dispersed when heated at 45-56 degrees C for 30 minutes. A few of the strains of S. saprophyticus tested also agglutinated human, bovine, and guinea pig erythrocytes.

Animals↗

PubMed1990

Influence of nonlactating and peripartum bovine mammary secretions on growth of Staphylococcus species.

Bovine mammary secretions from individual quarters were collected from five cows at 0, 14, and 28 d of involution, at parturition, and 14 d after parturition and used in a microassay to evaluate growth of several Staphylococcus species. All Staphylococcus species evaluated followed similar growth patterns in secretions. Mammary secretions obtained at 14 and 28 d of involution were poor media for growth of Staphylococcus species. Conversely, mammary secretions collected at cessation of milking, parturition, and early lactation supported growth of all species evaluated. Growth of Staphylococcus species in mammary secretions differed slightly among cows but was similar among quarters of a cow. Results suggested that the ability of bovine mammary secretions to support or inhibit growth of Staphylococcus species was related to functional states of the mammary gland.

Animals↗

PubMed1997

Comparison of screening methods to identify methicillin-resistant Staphylococcus aureus.

Screening methods to identify methicillin-resistant Staphylococcus aureus (MRSA) were compared using 96 isolates representing 17 distinct clones. The sensitivity of four commercial agglutination tests was determined in comparison to the tube coagulation test, and the results related to the presence of the coagulase gene. The broth screening test, agar dilution test and disc diffusion test were carried out, and the results related to the presence of the mecA gene. Mannitol salt agar and Iso-Sensitest agar with varying salt supplements were used. All agglutination tests had high rates of detection of Staphylococcus aureus (95.8-99.0%). Resistance in mecA gene-positive Staphylococcus aureus isolates was correctly detected by the oxacillin broth test, the agar dilution test and the disc diffusion test on mannitol salt agar, whereas on Iso-Sensitest agar detection rates were lower (between 68.5% and 94.4%, depending on the salt supplement). Incubation of the Iso-Sensitest plates for 48 hours significantly improved the rate of detection of resistance, but increased the major error rate up to 71.4%. MecA gene-positive Staphylococcus aureus isolates not detected by the disc diffusion test on Iso-Sensitest agar had significantly lower oxacillin minimal inhibitory concentration values and were significantly less resistant to a variety of antibiotics. Thus, mannitol salt agar might be a suitable medium for use in the disc diffusion and agar dilution test to detect resistance to oxacillin in Staphylococcus aureus.

Agglutination Tests↗

PubMed1991

Activity of antibiotics against Staphylococcus aureus within polymorphonuclear neutrophils.

The intracellular location of certain strains of Staphylococcus aureus serves as a reservoir of bacteria which is thought to be important in therapy of recurrent infections in humans and in chronic staphylococcal mastitis in dairy cows. This overview summarizes data pertaining to the intracellular survival of Staphylococcus aureus within polymorphonuclear neutrophils (PMNs) both in vitro and in vivo in the face of antibiotic treatment. While compounds such as rifampin, clindamycin, erythromycin, and ciprofloxacin have been shown to be rapidly taken up by PMNs, the ability of antibiotics to concentrate within PMNs did not strictly correlate with their ability to kill intracellular Staphylococcus aureus. Rifampin and ciprofloxacin have been shown to be the most effective intraphagocytic killing agents, while clindamycin and erythromycin were inactive in these in vitro assays. In vivo, in therapy of Staphylococcus aureus arthritis and peritonitis in humans and in certain mouse models rifampin has generally been shown to be more effective than comparator antibiotics. In a staphylococcal subcutaneous abscess model, however, clindamycin was very effective in curing the Staphylococcus aureus abscesses in this system where PMNs were the primary inflammatory cells involved. The intracellular bacterial counts decreased as rapidly as the extracellular bacteria. Rifampin was also effective in the abscess model but ciprofloxacin was ineffective at the highest doses tested. The relevance of in vitro and in vivo models and the importance of PMNs as a reservoir of infection in staphylococcal diseases in humans and the dairy cow are discussed.

Anti-Bacterial Agents↗

PubMed1984

Opsonic activity of fibronectin in the phagocytosis of Staphylococcus aureus by polymorphonuclear leukocytes.

The effect of the opsonic activity of human purified fibronectin on phagocytosis of Staphylococcus aureus by human polymorphonuclear leukocytes was investigated. After opsonization with fibronectin there was a significant increase in the rate of phagocytosis of four out of six Staphylococcus aureus strains. Both attachment to and ingestion by leukocytes was affected, as revealed by lysostaphin treatment. Incubation of leukocytes with fibronectin prior to phagocytosis did not enhance the phagocytosis of Staphylococcus aureus. This shows that the observed enhancement of phagocytosis was dependent on the binding of fibronectin to Staphylococcus aureus. The ability of fibronectin to opsonize different strains of Staphylococcus aureus varied with the strain. A variation was also observed in fibronectin-induced phagocytosis by leukocytes from different donors.

Blood Bactericidal Activity↗

PubMed2001

Predisposing factors and outcome of Staphylococcus aureus bacteremia in neutropenic patients with cancer.

Staphylococcus aureus caused 30 of 438 (7%) cases of bacteremia in neutropenic patients with cancer during a 10-year study period. Acute leukemia as an underlying disease and severe oral mucositis were more frequent among patients with Staphylococcus aureus bacteremia (57% vs. 33%, P = 0.01, and 32% vs. 12%, P = 0.006, respectively) than among the 151 patients who had gram-negative bacteremia during the same study period. The most frequent source of Staphylococcus aureus bacteremia was the venous catheter (35% vs. 1%; P = 0.00001). Septic metastases were more frequent in patients with Staphylococcus aureus bacteremia (14% vs. 4%, P = 0.03). Attributable mortality was 10% and overall mortality 23%. Staphylococcus aureus bacteremia remains a significant cause of morbidity and mortality in neutropenic patients with cancer.

Adolescent↗

PubMed2002

Risk factors for nasal carriage of Staphylococcus aureus in infectious disease patients, including patients infected with HIV, and molecular typing of colonizing strains.

Nasal carriage is an important risk factor for Staphylococcus aureus infection, particularly in HIV-infected individuals. In this analytical cross-sectional study, a variety of probable risk factors associated with nasal carriage of Staphylococcus aureus were investigated. HIV-infected patients were examined within a larger cohort of infectious diseases patients. Staphylococcus aureus strains from HIV-infected and non-HIV-infected carriers were identified by molecular biological analysis. One hundred seventy infectious disease patients, 47 of them infected with HIV, were included. All patients were admitted to the University Hospital of Vienna, Austria, between January and July 1999. Independent significant effects on Staphylococcus aureus nasal carriage were found to be HIV status (OR 2.5, 95% CI 1.1-5.6; P=0.0303), history of operation or severe wound within 3 months prior to admission (OR 4.0, 95% CI 1.3-13.0; P=0.0208), presence of an intravenous device within 2 weeks prior to admission (OR 10.8, 95% CI 2.0-59.4; P=0.0065), and intake of antibiotics within 2 weeks prior to hospitalisation (OR 0.2, 95% CI 0.09-0.6; P=0.0016). Molecular analysis of the Staphylococcus aureus strains revealed that the strains in both groups resembled those of healthy nonhospitalized carriers in the community.

AIDS-Related Opportunistic Infections↗

PubMed2001

Antimicrobial susceptibility of respiratory isolates of Enterobacteriaceae and Staphylococcus aureus in Italy: incidence and trends over the period 1997-1999.

The antibiotic susceptibility of members of the family Enterobacteriaceae and of Staphylococcus aureus strains isolated from the respiratory tract was assessed over the period 1997-1999 as part of the Italian Epidemiological Observatory survey sponsored by the Smith-Kline Foundation. A standardised method was used to determine the MICs of 22 antibiotics against isolates of Klebsiella pneumoniae (n=870), Escherichia coli (n=684), Enterobacter cloacae (n=342), Enterobacter aerogenes (n=187) and Serratia marcescens (n=135) as well as the MICs of 11 antibiotics against isolates of Staphylococcus aureus (n=1,606). Overall, the susceptibility rate of Enterobacteriaceae isolates was > or = 90% to 5 agents (meropenem, imipenem, amikacin, cefepime and gentamicin); 89-80% to 2 agents (ciprofloxacin and tobramycin); and <80% to 11 agents (cefotaxime, piperacillin-tazobactam, trimethoprim-sulfamethoxazole, cefetamet, ceftriaxone, ceftazidime, aztreonam, ticarcillin-clavulanate, tetracycline, piperacillin, cefuroxime, chloramphenicol, ticarcillin, amoxicillin-clavulanate and amoxicillin). During the 3-year monitoring period, antibiotic susceptibility increased in Klebsiella pneumoniae against amoxicillin-clavulanate, in Escherichia coli against third-generation cephalosporins and aztreonam, in Enterobacter aerogenes against amoxicillin and piperacillin-tazobactam and in Serratia marcescens against most of the antibiotics. In contrast, Enterobacter cloacae showed a tendency to develop resistance to cefetamet, amikacin and ciprofloxacin. Of the total number of Staphylococcus aureus strains, 38% were methicillin resistant. Nearly 80% of the methicillin-resistant strains displayed a multiresistance pattern (additional resistance to 2 or more non-beta-lactam antibiotics). Rates of susceptibility of particular species (Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus) were compared using strains from different geographical areas of Italy (northern, central and southern) and from different nosocomial areas (outpatients, intensive care unit [ICU] inpatients, non-ICU inpatients). Susceptibility of Klebsiella pneumoniae to several antibiotics was lower in southern Italy, whereas the incidence of methicillin-resistant strains was higher in northern and central Italy. The susceptibility of Escherichia coli was similar in all three areas. No significant differences in susceptibility of Klebsiella pneumoniae or Escherichia coli were found between strains from inpatients and outpatients or from inpatients admitted to ICU and non-ICU units. The incidence of methicillin-resistant Staphylococcus aureus was higher in ICU inpatients (52%) than in non-ICU inpatients (38%) and lower in outpatients (19%) than in inpatients.

Drug Resistance, Bacterial↗

PubMed2005

Detection of galangin-induced cytoplasmic membrane damage in Staphylococcus aureus by measuring potassium loss.

Galangin is one of the active antimicrobial principles of propolis or 'bee glue' and Helichrysum aureonitens, a perennial herb used by South African indigenes to treat infection. The effect of this compound and antibacterial agents with known mechanisms of action upon the cytoplasmic membrane integrity of Staphylococcus aureus was investigated by comparing potassium loss profiles from bacterial cell suspensions. Using an agar dilution assay, the minimum inhibitory concentrations (MICs) of the flavonol galangin, the bacteriostatic antibiotic novobiocin and the bactericidal antibiotic penicillin G against Staphylococcus aureus NCTC 6571 were determined as being 50 microg/mL, 62.5 ng/mL and 31.3 ng/mL, respectively. When 5x10(7)cfu/mL Staphylococcus aureus were suspended in 'potassium-free' media containing 50 microg/mL galangin, a 60-fold decrease in viability was observed after 12 h. Populations of 1x10(9) cfu/mL Staphylococcus aureus incubated for 12 h in 50 microg/mL galangin lost 21% more potassium than untreated control populations. Novobiocin had no effect on potassium loss, but populations incubated in 31.3 ng/mL penicillin G exhibited a 6% increase in potassium loss. This data clearly demonstrates that galangin causes a significant increase in potassium loss from Staphylococcus aureus cells, which may be attributed to either direct damage to the cytoplasmic membrane or indirect damage effected through autolysis/weakening of the cell wall and consequent osmotic lysis.

Anti-Bacterial Agents↗