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PubMed1981

Temperature effect on cephalothin sensitivity of methicillin-resistant Staphylococcus aureus.

Nineteen methicillin-resistant Staphylococcus aureus isolates from clinical specimens were tested for cephalothin sensitivity by disk diffusion and tube-dilution methods using incubation temperatures of 35 C and 30 C. Resistant colonies were observed to grow within the zones of antibiotic inhibition for 17 of the 19 isolates at 30 C but not at 35 C incubation. Twenty control strains known to be methicillin-sensitive did not show these resistant colonies at 30 C. Five of the methicillin-resistant isolates were sensitive, one of intermediate sensitivity to cephalothin, and the rest were resistent by tube-dilution testing at 35 C. At 30 C, however, two isolates were of intermediate sensitivity, and the rest were resistant to cephalothin by tube-dilution testing. These observations strongly suggest that the 30 C incubation temperature is more reliable in detecting in-vitro resistance of methicillin-resistant strains of Staphylococcus aureus to cephalothin in agar as well as in liquid media.

Cephalothin↗

PubMed1984

Plasmid profiles of Staphylococcus aureus causing bovine mastitis.

Plasmid profiles of Staphylococcus aureus, isolated from herds affected with chronic bovine mastitis, are heterogeneous, as shown by the study of 85 strains from 18 different farms. The strains isolated within a herd sometimes show related plasmid patterns, although even strains isolated from different quarters of the same udder may show variations in their plasmid content. Strains without antibiotic resistance are frequently free of plasmids. Therefore, the existence of mastitis Staph. aureus virulence plasmids is unlikely. Staphylococcus aureus, resistant to penicillin and streptomycin from 9 different farms show related plasmid patterns. This result confirms a geographic spread of certain mastitis Staph. aureus strains.

Animals↗

PubMed1993

[Acute Staphylococcus aureus myocarditis in AIDS. 2 cases].

The authors report two cases of acute myocarditis due to Staphylococcus aureus in patients with AIDS. There was no history of opportunist infections in either case but the CD4 lymphocyte levels were very low. The myocarditis caused acute cardiac failure and death. Histological examination showed microabscesses filled with Gram positive cocci throughout the myocardium. Bacteriological studies identified the Staphylococcus aureus. Staphylococcus aureus myocarditis without endocardial or pericardial involvement is very rare. It is the result of septic emboli in the cardiac microcirculation. Bacterial myocarditis has rarely been diagnosed in HIV positive patients. Both our cases featured severe cell-mediated immunodeficiency without associated neutropaenia. The decreased bactericidal activity of the neutrophil polynuclears and/or a deficit in the immunity mediated by the B-cell lymphocytes in AIDS could explain the lethal septic complications observed in our two cases.

AIDS-Related Opportunistic Infections↗

PubMed2004

Novel non-mecA-containing staphylococcal chromosomal cassette composite island containing pbp4 and tagF genes in a commensal staphylococcal species: a possible reservoir for antibiotic resistance islands in Staphylococcus aureus.

Among methicillin-resistant Staphylococcus aureus isolates, a staphylococcal chromosomal cassette containing the mecA gene (SCCmec) is integrated into the chromosome at a unique site. SCCmec also contains unique ccrAB recombinase genes mediating its integration and excision from the genome and is flanked by characteristic left and right direct- and inverted-repeat sequences. A few non-mecA-containing SCC elements that have the other molecular features described above have recently been described. The origin of these cassettes is not clear. We have identified two new members of the SCC family integrated within orfX in Staphylococcus epidermidis strain ATCC 12228, neither of which carries mecA. One is a 57-kb element flanked by a unique 28-bp SCC direct repeat. It was called the SCC composite island (SCC-CI) because it carries a 19-kb SCC element (SCCpbp4) nested within it. SCCpbp4 contains pbp4 and tagF genes, as well as one pair of ccrAB genes (allotype 2) flanked by classical SCC-specific terminal repeats. External to SCCpbp4, SCC-CI contains a second pair of ccrAB genes (allotype 4), three IS431 elements, and genes mediating resistance to heavy metals. Genes mediating restriction-modification that may facilitate horizontal transfer are also present within SCC-CI, both within and outside SCCpbp4. Several novel arrangements of the SCC direct and inverted repeats were identified. Several long stretches of homology with other SCCs were found within and outside SCCpbp4. In view of the fact that SCC-CI was found in a commensal species, it may represent a reservoir for sequences involved in genetic shuffling between staphylococci and may contribute to the diversity found in SCC elements.

Amino Acid Sequence↗

PubMed1988

Microbiologic and therapeutic aspects of Staphylococcus aureus in cystic fibrosis patients.

Staphylococcus aureus was the most frequent (28.8%) gram-positive organism in 149 cystic fibrosis patients. Next to Pseudomonas aeruginosa, S. aureus was the most persistent bacterial pathogen as well. Persistence was not correlated to the age or sex of our patients. Colonization by S. aureus was not prevented completely by oral antibiotics like cotrimoxazole or oral cephalosporins. Persisting staphylococci were less susceptible to the antibiotic substances used than strains detectable only sporadically. Increase of sputum concentrations of P. aeruginosa was observed in episodes of treatment with purely antistaphylococcal compounds. Improvement of effectiveness of antibacterial therapy may be achievable by antibiotics more active against staphylococci, active both against staphylococci and P. aeruginosa, or adequate drug combinations.

Anti-Bacterial Agents↗

PubMed2000

[Evaluation of methicillin-resistance in Staphylococcus aureus by the agar disk diffusion method and PCR].

Staphylococcus aureus is a widespread human pathogen. One the most striking characteritics of this bacterium is resistance to methicillin and all beta-lactam antibiotics. The agar disk diffusion method is the most widely used in vitro susceptibility test, but recently molecular methods, e.g. Polymerase Chain Reaction, have been also introduced. We compared the detection of methicillin resistant coagulase positive Staphylococcus aureus isolated from clinical materials in Silesian microbiological laboratories by diffusion method and PCR through the detection of nuc and mec A genes. Our results show that PCR used for the detection of mec A gene increases the detection of methicillin-resistant Staphylococcus aureus strains by 10% as compared to the agar disk diffusion method. Among Staphylococcus aureus strains, detected as methicillin-resistant, 17% of organisms showed no presence of mec A gene.

Colony Count, Microbial↗

PubMedDate not supplied

[Methicilline-sensitive and methicilline-resistant Staphylococcus aureus related morbidity in chronic wounds: a prospective study].

OBJECTIVE: Staphylococcus aureus is the most common bacteria responsible for cutaneous infections. Its capacity to adapt has led to the selection of methicilline-resistant strains (MRSA). These strains create specific problems in their management in dermatology (mode of contamination, treatment, added costs, increased nosocomial risks). The objective of our study was to search for morbidity of MRSA in chronic cutaneous wounds in hospital settings and assess the need of systemic antibiotic therapy. PATIENTS AND METHODS: We have conducted a one-year prospective study. All the patients hospitalized in the department with leg ulcers or foot wounds were included. Following local sampling for bacteriological examination, three groups were constituted: methicilline-sensitive patients with staphylococcus aureus (MSSA), methicilline-resistant staphylococcus aureus patients and patients in whom these bacteria were absent. Only the first two groups were compared after studying the past history, clinical description of the wound at the start of the study, results of the infectious bacteriology and of the clinical and bacteriological evolution of the wounds. RESULTS: The two groups studied were similar in number, past history, clinical aspect and therapeutic management. Only malnutrition was more frequent in patients exhibiting MRSA. There was no difference with the evolution of the wounds. CONCLUSION: Our study did not reveal any difference in the morbidity of staphylococcus aureus in the cutaneous wounds whether methicilline sensitive or resistant. Systematic antibiotherapy is not justified in the absence of signs of infection.

Adult↗

PubMedDate not supplied

Clinical significance of Staphylococcus aureus in cystic fibrosis.

Staphylococcus aureus is usually the first bacterial pathogen detected in the respiratory secretions of patients with cystic fibrosis. This review briefly examines the characteristics of this host-parasite relationship in terms of current knowledge about the toxicity of the organism, mechanisms of respiratory tract injury, therapy and prevention. Recent evidence indicates that viral infection plays a role in the initial damage of the respiratory epithelial cells and staphylococcal colonization ensues. Affinity of staphylococcus for cystic fibrosis mucus, mucociliary abnormalities and unknown factors contribute to persistent colonization with this organism causing progressive pulmonary damage and possibly influencing Pseudomonas infection. Most of the evidence today indicates that aggressive antibiotic management directed against S. aureus is warranted in all stages of bronchopulmonary infection in cystic fibrosis. Future efforts to prevent colonization and the toxic and immunopathic consequences of staphylococcal infection are also important. One study is in progress that examines antibiotic prevention in the early stages of cystic fibrosis. Future investigations need to address other strategies including vaccines, antitoxins, anti-inflammatory agents, immunomodulators, and antibiotic regimens.

Anti-Bacterial Agents↗

PubMed1995

Staphylococcus aureus: a review of the literature.

Staphylococcus aureus has a long association with nosocomial infection. Problems date from the 1950s, although methicillin-resistant Staphylococcus aureus (MRSA) did not emerge until the following decade. Initially the pathogenicity of antibiotic-resistant strains was underestimated, and is still sometimes questioned, but today most authorities consider MRSA a serious threat, especially given current preoccupation with cost-effectiveness within the health service: nosocomial infection is associated with increased expenditure and may be regarded as a hallmark of indifferent nursing and medical care. This review documents the emergence of MRSA and recognition of the ensuing problems throughout the 1980s and early 1990s, with suggestions for nursing activities which could contribute towards improved control. Lessons learnt during outbreaks are seen to be of value, but there is also a need for staff at ward level to review routine practice continually so that awareness of activities likely to result in cross-infection is maintained. The use of protective clothing emerges as less important than handwashing, which may be periodically audited to maintain standards.

Cross Infection↗

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↗

PubMed2002

Methicillin-resistant Staphylococcus aureus infection in a cardiac surgical unit.

BACKGROUND: Increased antibiotic resistance of common bacteria is attributed in part to the widespread use of various antibiotic agents. Prophylactic and therapeutic antibiotic treatments are routinely used in cardiac surgical units, and it is no surprise that methicillin-resistant Staphylococcus aureus infection is becoming a major cause of surgical infections in cardiac patients. METHODS: We reviewed our experience with patients who underwent cardiac surgery and experienced infection caused by methicillin-resistant Staphylococcus aureus. Between 1992 and 2000 at the Montreal Heart Institute, 39 patients had methicillin-resistant Staphylococcus aureus surgical infections, and 13,199 patients underwent cardiac surgery. The yearly incidence of methicillin-resistant Staphylococcus aureus infection, the relative risk of acute mediastinitis and of superficial wound infections or other types of methicillin-resistant Staphylococcus aureus infection episodes, and the effect of preventive measures were analyzed. RESULTS: The annual incidence of methicillin-resistant Staphylococcus aureus acute mediastinitis decreased from 0.37% (5/1321) of cardiac patients in 1992 and 0.44% (6/1355) in 1993 to 0% between 1994 and 1997, 0.13% (2/1528) in 1999, and 0% (0/1700) in 2000. The total incidence of methicillin-resistant Staphylococcus aureus infection, including mediastinitis, superficial and deep sternal and leg wound infection, and all systemic infection episodes ranged from 0.68% of patients in 1992 and 0.96% of patients in 1993 to 0.46% of patients in 1999 and 0.53% of patients in 2000. The relative risk of severe mediastinal methicillin-resistant Staphylococcus aureus infection to all other methicillin-resistant Staphylococcus aureus infection episodes decreased from 1.65 in 1992 to 0.41 in 1999 and 0 in 2000. Beginning in 1993, all patients given a diagnosis methicillin-resistant Staphylococcus aureus infection and all nasal carriers of methicillin-resistant Staphylococcus aureus were strictly isolated on the surgical unit, and vancomycin was used as the prophylactic antibiotic agent for cardiac surgery in these patients. Moreover, since 1998, all patients admitted in the hospital were screened, and nasal carriers were isolated and treated with topical antibiotic ointment. CONCLUSION: Mediastinal and other infections caused by methicillin-resistant Staphylococcus aureus have a significant morbidity in cardiac surgical patients. After an outbreak of methicillin-resistant Staphylococcus aureus mediastinal infections, several preventive measures to control methicillin-resistant Staphylococcus aureus contamination of surgical patients were implemented (nasal screening, preventive isolation, application of mupirocin, prophylaxis with vancomycin and alcohol gels) and were effective in decreasing the incidence of methicillin-resistant Staphylococcus aureus infection and mediastinitis after cardiac surgery.

Acute Disease↗

PubMed2006

Family outbreaks of invasive community-associated methicillin-resistant Staphylococcus aureus infection.

Outbreaks of invasive methicillin-resistant Staphylococcus aureus infection within families are unusual. We investigated 2 family clusters of invasive methicillin-resistant Staphylococcus aureus infection, including 1 in which a young mother died of fulminant pneumonia. Although surveillance via culture of family contacts of patients with invasive methicillin-resistant Staphylococcus aureus infection is not currently recommended, such clusters should stimulate reevaluation of preventive measures.

Adolescent↗

PubMed2003

Genetic basis of neonatal methicillin-resistant Staphylococcus aureus in Japan.

Methicillin-resistant Staphylococcus aureus (MRSA) is still one of major problems of drug-resistant microorganisms and healthcare-acquired infections. Methicillin-resistant Staphylococcus aureus is highly prevalent in patients in neonatal intensive care units (NICU) in Japan. The most predominant MRSA in NICU is multidrug resistant and produces superantigenic exotoxin, toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin C (SEC). These predominant MRSA strains belong to coagulase type II, SCCmec type II, mecA-Tn554 polymorph type I-A and show closely related pulse field gel electrophoresis types. The dissemination of MRSA is wide, and there is a pandemic distribution of a single MRSA clone in the NICU of Japan. Since 1992, the nationwide spread of this clone has also led to the development of a new neonatal disease known as neonatal toxic shock-like exanthematous disease (NTED), which is caused by overactivation of vbeta2+ T cells induced by TSST-1. The spread of MRSA in NICU in Japan has been attributed to overcrowding, high rates of extremely low birthweight babies, understaffing, low control measures of infection and overuse of antibiotics. The environment of NICU and infection control intervention should be improved and a new strategy for control like vaccination or probiotics is required.

Bacterial Proteins↗

PubMed1996

[Prevalence of Staphylococcus aureus among food handlers from a metropolitan university in Chile].

BACKGROUND: An important agent of food intoxication is Staphylococcus aureus, that is able to produce enterotoxins. AIM: To detect Staphylococcus aureus contamination in cafeteria food handlers of a Chilean University. SUBJECTS AND METHODS: Nose, throat, hands and nail samples from 87 food handlers were obtained for microbiological examination. RESULTS: Fifty seven subjects (65.5%) were carriers of Staphylococcus aureus. Enterotoxigenic Staphylococcus aureus was found in 36 subjects (41%). The most frequently found enterotoxin was type B (18 samples) followed by type D (12 samples). Men bad a higher frequency of contamination than women (83 and 57% of positive samples respectively). CONCLUSIONS: The frequency of Staphylococcus aureus contamination among food handlers is high and should prompt personal and environmental hygienic measures.

Carrier State↗

PubMed2001

A comparison between septic bursitis caused by Staphylococcus aureus and those caused by other organisms.

Septic bursitis is an infection that usually involves olecranon and prepatellar bursae. Staphylococcus aureus is responsible for around 80% of cases. However, information regarding bursitis caused by non-Staphylococcus aureus microorganisms (NSAB) is scant. In this paper we describe the characteristics of NSAB and emphasise differences between these and Staphylococcus aureus bursitis (SAB). A retrospective study of all cases with septic bursitis seen between January 1991 and June 1998 at one university hospital was conducted. Only cases in which bursal fluid culture yielded growth of a microorganism were analysed. A literature review was conducted for completeness. Fifty-seven episodes of septic bursitis in 56 patients were studied: 47 of these were caused by Staphylococcus aureus and 11 by non-Staphylococcus aureus microorganisms. Forty-three SAB patients were male (91%). Mean age at diagnosis was 50 years (range 20-85 years). The presentation of bursitis had a seasonal trend, with a peak in the summer. Twenty-three patients (51%) had occupations involving frequent or sustained pressure on the bursae. Other risk factors were recent trauma in 11 (23%), alcoholism in six (13%), pre-existing bursal disease in five (11%), and chronic obstructive pulmonary disease in four (9%). There were 20 cases of olecranon bursitis (43%), 25 of prepatellar bursitis (53%) and two of first metatarsophalangeal bursitis. Characteristics of patients from the literature review were similar. Eight NSAB patients (73%) were male. Mean age at diagnosis was 46.9 (range 29-83 years). Two patients were plumbers and one a stonemason. Five (45%) had neither putative systemic nor local risk factors. There were five olecranon (45%), five prepatellar (45%), and one external malleolus bursitis. Infection by a mixed flora was common. Unlike SAB, the presentation of cases did not have a seasonal trend. The clinical spectrum of non-Staphylococcus aureus bursitis (NSAB) differs from that of Staphylococcus Aureus bursitis (SAB), and this should be considered in the initial diagnosis of septic bursitis.

Adult↗

PubMed1985

Presence of laminin receptors in Staphylococcus aureus.

A characteristic feature of infection by Staphylococcus aureus is bloodstream invasion and widespread metastatic abscess formation. The ability to extravasate, which entails crossing the vascular basement membrane, appears to be critical for the organism's pathogenicity. Extravasation by normal and neoplastic mammalian cells has been correlated with the presence of specific cell surface receptors for the basement membrane glycoprotein laminin. Similar laminin receptors were found in Staphylococcus aureus but not in Staphylococcus epidermidis, a noninvasive pathogen. There were about 100 binding sites per cell, with an apparent binding affinity of 2.9 nanomolar. The molecular weight of the receptor was 50,000 and pI was 4.2. Eukaryotic laminin receptors were visualized by means of the binding of S. aureus in the presence of laminin. Prokaryotic and eukaryotic invasive cells might utilize similar, if not identical, mechanisms for invasion.

Animals↗

PubMed1999

Presence and expression of collagen adhesin gene (cna) and slime production in Staphylococcus aureus strains from orthopaedic prosthesis infections.

Prosthesis-associated infections still represent one of the most serious complications in the clinical use of biomaterials. The most frequent causes are Staphylococcus aureus and Staphylococcus epidermidis. Several studies have been devoted to identify adhesion mechanisms for these bacteria. Slime in particular has been extensively investigated. Recently, in Staphylococcus aureus species, considerable attention has been given to the host protein receptors that have been shown in in vitro assays to serve as substrates for bacterial adhesion. Collagen-rich tissues, as bone and cartilage, that are the preferential sites of staphylococcal infections, are also the tissues that harbour orthopaedic implants. These can be easily coated in vivo by collagen and thus become prone to adhesion of Staphylococci strains which carry the collagen adhesin gene (cna). In this study the frequency of cna was determined within a collection of 35 Staphylococcus aureus strains from orthopaedic prosthesis infections by a PCR method. Also the collagen-binding ability and slime forming capacity was evaluated. 29% of the strains were cna-positive and also able to bind collagen in vitro. 83% of the strains were slime forming. The results indicate that in the examined bacterial population slime-positive strains predominate over the cna-positive strains, with a striking association of the two adhesion mechanisms in cna-positive strains.

Adhesins, Bacterial↗

PubMed2003

Staphylococcus aureus colonization in a community sample of HIV-infected and HIV-uninfected drug users.

HIV-infected individuals, especially those with a history of injecting drug use, are at high risk of Staphylococcus aureus infection. Moreover, the use of antimicrobial agents for opportunistic infections may increase nasal colonization by antimicrobial-resistant Staphylococcus aureus in this population and, subsequently, levels of infection with multidrug-resistant Staphylococcus aureus in the community. Between February 1999 and March 2000, 500 subjects from a community-based cohort of drug users completed an interview and underwent a physical exam. Risk factors for colonization by Staphylococcus aureus were examined, the antibiotic susceptibility profiles of all strains were determined, and DNA strain analysis was performed. One hundred twenty (24%) subjects had positive Staphylococcus aureus nasal cultures. Only HIV infection and homelessness were associated with Staphylococcus aureus colonization. Ten (8%) isolates were methicillin-resistant Staphylococcus aureus. Methicillin-resistant Staphylococcus aureus isolates were found more frequently among HIV-infected than HIV-uninfected respondents (14% vs. 3%, P=0.04). Among those colonized and HIV infected, the mean number of resistant isolates was higher for those currently reporting antibiotic use (5.0 vs. 2.3, P<0.001) and for those with CD4+ counts <or =200/ microl (3.8 vs. 2.3, P=0.02). The increased use of antimicrobial agents in HIV-infected individuals colonized with Staphylococcus aureus may be an underlying mechanism that contributes to the presence of multidrug-resistant Staphylococcus aureus in the community.

AIDS-Related Opportunistic Infections↗