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PubMed2002

[Arbekacin resistant gene, aacA/aphD, in Staphylococcus aureus is lost during in vitro passage].

We analyzed for the presence of the aacA/aphD gene in arbekacin resistant-Staphylococcus aureus. Tested strains were 50 clinically isolated Staphylococcus aureus that had an MIC of more than 2 micrograms/ml for arbekacin. Among the primary cultures, aacA/aphD genes were detected in 42 of 50 strains(84%) overall, including 34 of 41 Methicillin resistant Staphylococcus aureus(MRSA) strains, and 8 of 9 strains of Methicillin sensitive Staphylococcus aureus(MSSA). After 10 or 20 passages, the aacA/aphD gene was lost in 5 strains of MRSA and 2 strains of MSSA. In the strains that lost the gene, the MIC of arbekacin was reduced remarkably in 3 strains of MRSA and 2 strains of MSSA. Further, MICs of arbekacin decreased along with passages even in the strains that did not loose the aacA/aphD gene, as well as in the strains that did not possess the aacA/aphD gene originally. The fact that MIC values are easily reduced with in vitro passage is important to consider when performing the arbekacin-resistance test for Staphylococcus aureus.

Aminoglycosides↗

PubMed2002

Methicillin resistant Staphylococcus aureus: a multicentre study.

OBJECTIVE: To determine the frequency of Methicillin resistance Staphylococcus aureus infection in major cities of Pakistan. SETTING: Various laboratories of the country with one as the central Laboratory. MATERIALS AND METHODS: Seven hundred and ninety two consecutive clinical isolates of Staphylococcus aureus were collected from 8 laboratories all over Pakistan i.e. Karachi, Peshawar, Lahore, Sukkhur, Islamabad, Quetta, and Mirpur, Azad Kashmir. Antibiotic sensitivity was done by Kirby Bauer disc diffusion method and MIC of Vancomycin was determined by 'E' test. RESULTS: Forty two percent of the isolates were found to be Methicillin resistant staphylococcus aureus (MRSA) while no Vancomycin resistance was encountered. CONCLUSION: Methicillin resistant Staphylococcus aureus (MRSA) are seen in the local population with frequencies varying between 2-61% highest incidence is seen in the major cities of the country. Fortunately no Vancomycin resistant Staphylococcus has been isolated from any of the major cities.

Developing Countries↗

PubMed2002

[The change in CD14 mRNA expression in rats with scald injury and Staphylococcus aureus challenge].

OBJECTIVE: To investigate the potential role and changes in CD14 in postburn Staphylococcus aureus sepsis. METHODS: Wistar rats were subjected to a 20% total body surface area (TBSA) full-thickness thermal injury and followed by Staphylococcus aureus challenge. Plasma and tissue samples from liver, kidneys, lungs and heart were collected to determine endotoxin (lipopolysaccharide, LPS) levels and CD14 mRNA expression. RESULTS: It was found that after thermal injury combined with Staphylococcus aureus sepsis, LPS levels in various tissues were markedly increased, peaking at 2 approximately 6 h (P < 0.05), then returned to baseline at 24 h. Plasma LPS level was also increased significantly at 2hrs after Staphylococcus aureus challenge compared with that in normal control animals (0.3056 EU/ml vs. 0.1250 EU/ml, P < 0.05). In addition, the intestinal diamine oxidase (DAO) activity decreased (P < 0.05). This indicated that the integrity of intestinal mucosa was damaged. Meanwhile, tissue CD14 mRNA expressions were up-regulated in all tissues (P < 0.05), especially in lungs. CONCLUSION: These data suggested that gut-originated LPS translocation and CD14 mRNA expression could be induced by thermal injury with Staphylococcus aureus sepsis. The up-regulation of CD14 gene expression might be associated with the local endotoxin activation secondary to postburn sepsis.

Animals↗

PubMed2004

Atopic dermatitis and Staphylococcus aureus.

Atopic dermatitis is chronic, pruritic inflammatory skin disorder strongly influenced by environmental factors. Staplylococcus aurcus is the common pathogen and colonize the normal skin but it is not number of normal skin flora. Damaged protective skin function by atopic dermatitis, the disturbance of quantity and quality of lipids of stratum corneum are some of the reasons for increasing degree of skin colonisation with staphylococcus aureus. We had presented frequency of the isolation staphylococcus aureus from eczematous atopic skin, from the nose and throat of atopic patients and also from clinically unaffected atopic skin in the group of 30 children compared with 15 healthy children without positive atopic family history. Staphylococcus aureus had been significantly more isolated by all earlier mentioned places in atopic group of children. There is a direct correlation between intensity and also extensity of atopic dermatitis and frequency of the isolation of staphylococcus aureus from mentioned places. The role of staphylococcus aureus in pathogenesis of atopic dermatitis was discussed.

Adolescent↗

PubMed1992

[Hospital personnel who are nasal carriers of methicillin-resistant Staphylococcus aureus. Usefulness of treatment with mupirocin].

BACKGROUND: The evaluation of health care workers role in methicillin-resistant Staphylococcus aureus outbreaks and the efficacy of mupirocin as a topical agent for nasal carriers. METHOD: Microbiologic study of nasal microflora of 1547 health care workers from the San Carlos University Hospital and 108 health care workers from related hospitals while an outbreak of methicillin-resistant Staphylococcus aureus nosocomial infections is in progress at San Carlos University Hospital. Assessment of the efficacy of mupirocin nasal ointment for nasal carriers using microbiologic controls of nasal and pharyngeal swabs at the end of treatment and two weeks after. RESULTS: In San Carlos University Hospital a total of 53 health care workers with nasal carriage of methicillin-resistant Staphylococcus aureus were found. That figure represents a 3.4% of all health care workers studied and also a 15.4% of methicillin-resistance among all S. aureus isolated. Among health care workers from related hospitals, only one nasal carrier was found. Forty-seven of all 53 methicillin-resistant Staphylococcus aureus isolated from San Carlos University Hospital health care workers and the strain isolated from the related hospitals health care worker were similar to the epidemic strain responsible for the outbreak. Mupirocin, as nasal ointment, was useful in eliminating nasal colonization in all cases. CONCLUSIONS: When a nosocomial outbreak of methicillin-resistant Staphylococcus aureus infections is detected, health care workers are one of the most important reservoirs. Topical treatment with mupirocin (nasal ointment) is useful for eliminating the nasal carrier status.

Administration, Intranasal↗

PubMed2006

[Cloning of the conserved fragment of urease gene of Staphylococcus warneri].

PURPOSE: To obtain the clone of conserved fragment of urease gene of Staphylococcus warneri. METHODS: Urease activity was measured by phenol red assay. An internal fragment of the urease gene of Staphylococcus warneri was amplified by PCR with primers derived from conserved amino acid sequences of the large subunit of urease. The PCR product was then cloned into T-vector and sequenced. RESULTS: Urease activity of Staphylococcus warneri was positive. The internal fragment of urease gene of Staphylococcus warneri was highly homologous to known urease gene cluster of other bacteria. CONCLUSION: In this study, urease activity of Staphylococcus warneri was proved and the internal fragment of urease gene encoding conserved amino acid sequences was cloned.

Amino Acid Sequence↗

PubMedDate not supplied

[Isolation of Staphylococcus aureus by the Baird Parker method from powdered milk].

There are many media recommended for the isolation of Staphylococcus aureus from foods, but only with some media one can obtain a good growth started with stressed cells. The Baird Parker (BP) medium is considered the best choice to recover stressed cells, however, it is not as good a medium to isolate Staphylococcus aureus from powder milk. Therefore, it is important to count with alternative media to enhance the chance for Staphylococcus aureus to grow from dehydrated products. Thirty-one powder milk samples contaminated with Staphylococcus aureus were analysed by Baird Parker method, employing four culture media: Baird Parker (BP), Baird Parker + tween + MgCl2 (BPTM), Pork plasma with bovine fibrinogen agar (PPF) and Salt Milk agar (SL). Staphylococcus aureus was isolated in SL, 38.7%; in BP, 3.2%; in BPTM, 6.4%; and PPF, 0%.

Agar↗

PubMedDate not supplied

[Rapid agglutination tests for the identification of Staphylococcus aureus].

The article deals with rapid agglutination tests for Staphylococcus aureus identification which detect clumping factor and protein A. The tests were compared with standard diagnostic methods: free coagulase, bound coagulase and thermostable deoxyribonuclease, 190 Staphylococcus aureus strains have been examined of which, 105 methicillin susceptible strains, 85 methicillin resistant strains, and 32 coagulase negative staphylococci strains strains. The presence of clumping factor was detected in 100% of examined Staphylococcus aureus strains. No difference between methicillin susceptible strains and methicillin resistant strains was observed. Protein A was present in 96.1% of methicillin susceptible strains and in 90.6% of methicillin resistant Staphylococcus aureus strains. The same test showed false negative results in 12 strains: 4 of which methicillin susceptible and 8 methicillin resistant strains. Coagulase test slide method and protein A detecting test hand one false positive result each for coagulase negative staphylococci examined. The specificity of all tests used was 100% and 99.5% respectively. The authors suggest latex or hemagglutination tests detecting clumping factor and/or protein A for rapid Staphylococcus aureus strains identification in hospital environment. It is important to point out the possibility of getting false negative protein A detecting results in methicillin resistant strains.

Hemagglutination Tests↗

PubMed1985

[Identification of Staphylococcus aureus by the sero-inhibition of nuclease in blood culture broths].

Identification of Staphylococcus aureus in blood cultures by sero-inhibition nuclease test is described in this paper. No positive results were found in 392 Staphylococcus other than Staphylococcus aureus bacteremia. Only 0,8% Staphylococcus aureus bacteremia could not be detected. This sero-inhibition nuclease test provides a rapid, less than 3 hours, easy to perform, reliable method to identify Staphylococcus aureus in blood cultures. Results are obtained 24 hours earlier than the conventional methods.

Culture Media↗

PubMedDate not supplied

[Staphylococcus aureus septicemia in children: bacterial tolerance to vancomycin and serum bactericidal activity].

PURPOSE: To evaluate the susceptibility and of strains of Staphylococcus aureus isolated from children with septicemia, and to evaluate the importance of the serum bactericidal test. METHODS: Seventeen children with Staphylococcus aureus septicemia admitted to the Semi Intensive Care Unit of the Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo were studied. Twenty nine tests in the pico and 23 in the nadir of the antibiotics were made. RESULTS: Strains of Staphylococcus aureus from hospital origin were resistant to all the antibiotics but vancomycin and pefloxacin. The phenomenon of tolerance was seen in 5 (50%) of the strains that were tested for vancomycin, and 4 of the children had a bad evolution. The serum bactericidal tests showed titles in the pico > or = 1/8 in 55.5% of the observations; in this group the evolution was better. CONCLUSION: Strain of Staphylococcus aureus from hospital origin are multiresistant. The phenomenon of antimicrobial tolerance, as well as the serum bactericidal test may be related to a bad therapeutic evolution. The increasing value of the serum bactericidal test as a way to evaluate the therapeutic evolution in severe infections, and the role of the tolerance of the Staphylococcus aureus to vancomycin more studies.

Anti-Bacterial Agents↗

PubMed1994

[Activity of ofloxacin and other fluoroquinolones against staphylococcus which is either resistant to or susceptible to methicillin].

The activity of 37 antibiotics against 155 strains of Staphylococcus susceptible to methicillin (MS) and 107 strains of Staphylococcus resistant to methicillin (MR) was evaluated. Only vancomycin and teicoplanin remained active in relation to all the studied Staphylococcus strains. A high activity also was demonstrated by netilmicin (99.57%) and quinolones (more than 90%). The percentage of strains resistant to aminoglycoside, linkosamide, fluoroquinolones and other antibiotics was found to be higher within MR strains than in MS strains. All strains resistant to rifampin belonged to the MR Staphylococcus group. Among the 6 studied fluoroquinolones ofloxacin (97.71%) was found to be the most active. Three Staphylococcus aureus strains (MICOFX 16 micrograms/ml), one S-haemolyticus strain and one S. epidermidis strain (MICOFX 8 micrograms/ml) were the most resistant.

Anti-Infective Agents↗

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↗

PubMed1998

Methicillin resistant Staphylococcus aureus as a cause of chorioamnionitis.

BACKGROUND: Chorioamnionitis is a leading cause of morbidity and mortality in preterm infants. Only rarely is Staphylococcus aureus implicated. A case of methicillin resistant Staphylococcus aureus causing chorioamnionitis and endometritis is presented. CASE REPORT: A 39-year-old gravida 2 para 1 female, who previously worked as the unit clerk in the pediatric pulmonary unit of a children's hospital, was initially admitted at 22 weeks with a shortened cervix. The patient refused emergency cerclage. She was released from the hospital and returned at 25 4/7 weeks' estimated gestational age with possible spontaneous rupture of membranes. An amniocentesis was performed and revealed a gram stain positive for many gram positive cocci as well as a glucose of < 2 mg%. The patient was started on intravenous ampicillin and gentamicin and induction of labor with oxytocin was begun. Approximately 1 day after the patient's delivery, the culture from the amniocentesis was noted to have grown methicillin resistant Staphylococcus aureus, and the patient's (as well as the neonate's) regimen was switched to vancomycin. CONCLUSION: A Medline search revealed no cases of methicillin resistant Staphylococcus aureus causing chorioamnionitis. When chorioamnionitis or refractory endometritis is encountered in a patient who works in the health care industry, methicillin resistant staphylococcus aureus must be considered.

Adult↗

PubMed1964

ANTIBACTERIAL ACTIVITY OF SOME DERIVATIVES OF 7-AMINOCEPHALOSPORANIC ACID AGAINST STAPHYLOCOCCUS AUREUS AND SYNERGISM BETWEEN THESE AND OTHER ANTIBIOTICS.

The N-phenylacetyl derivative of 7-aminocephalosporanic acid (cephaloram) had roughly the same activity as benzylpenicillin against a number of Gram-positive organisms and about one-eighth of the activity of benzylpenicillin against penicillinsensitive strains of Staphylococcus aureus. This derivative and the N-alpha-phenoxypropionyl derivative of 7-aminocephalosporanic acid were 4 to 8 and 4 to 16 times as active as methicillin against penicillinase- and nonpenicillinase-producing staphylococcal strains, respectively. Neither the presence of horse serum nor changes in inoculum size appreciably affected the activities of any of the derivatives of 7-aminocephalosporanic acid which were tested. After forty-eight subcultures in the presence of antibiotic the increase in minimum inhibitory concentration against the staphylococcus was about four-times as great for cephaloram as for cephalosporin C. The resistant penicillinase-producing strains remained stable after six subcultures in antibiotic-free medium, and all the strains retained coagulase activity. Some degree of cross-resistance was found between the derivatives of 7-aminocephalosporanic acid and those of 6-aminopenicillanic acid. Synergism was observed in vitro between certain derivatives of 7-aminocephalosporanic acid and 6-aminopenicillanic acid when they were tested together or with fusidic acid or cephalosporin P(1) against a weak penicillinase-producing strain of Staphylococcus aureus. Cephalosporin C and cephalosporin C (pyridine), each in combination with benzylpenicillin, showed a significant degree of synergism in protection experiments in mice infected with a strong penicillinase-producing strain of Staphylococcus aureus.

Animals↗

PubMed1987

Evaluation of a conventional routine method for identification of clinical isolates of coagulase-negative Staphylococcus and Micrococcus species. Comparison with API-Staph and API-Staph-Ident.

A collection of 138 consecutive isolates from blood primarily identified as Gram-positive, cluster-forming, coagulase-negative cocci was examined by a conventional routine method for identification of clinical isolates of coagulase-negative Staphylococcus and Micrococcus species. The method was based on selected reactions from the Kloos & Schleifer scheme, utilizing the conventional media of Statens Seruminstitut. Double determinations for each isolate were performed by the conventional method. The results were compared with speciation by the commercial micromethods API-Staph and API-Staph-Ident. For control, 31 Staphylococcus and 13 Micrococcus reference strains were included. Of the 31 Staphylococcus spp. (reference strains), the conventional system, API-Staph, and API-Staph-Ident correctly identified 87%, 87% and 81%, respectively. Micrococcus spp. were only identified to genus level by the conventional method as well as by API-Staph. API-Staph-Ident is not designed for Micrococcus identification. Of 138 blood isolates, 121 belonged to the genus Staphylococcus while 17 were Micrococcus spp. S. epidermidis dominated with all three methods, constituting approx. 35% of the isolates tested. In only 57% of the isolates identification by all three methods agreed. The three methods were unable to put a name on 7.5% (conventional method), 10.7% (API-Staph) and 2.5% (API-Staph-Ident) of the isolates. Reproducibility was high with the conventional method (100% for the reference strains and 91% for blood culture isolates) as well as with API-Staph and API-Staph-Ident (88%/81% and 81%/81%, respectively). We concluded that our conventional system was able to identify most clinically significant staphylococcal species by means of relatively few tests with a high certainty and a high degree of reproducibility.

Bacteriological Techniques↗

PubMed1963

Repression of Staphylococcus aureus by food bacteria. I. Effect of environmental factors on inhibition.

The effects of environmental factors on the inhibition of an enterotoxin-producing strain of Staphylococcus aureus by food bacteria were investigated. Type of medium and temperature of incubation were important factors in determining the amount of inhibition. The pH range of maximal inhibition was found to be 7.4 to 6.2. Availability of oxygen was not a factor. As the ratios of inhibitor to staphylococcus were increased from 1:1 to 10:1 and 100:1, the amount of inhibition was markedly increased. Inhibition occurred in custard, where it increased with increasing ratios of effector to staphylococcus. The repression of the staphylococcus in all media usually was sufficient to be of practical significance.

Achromobacter↗

PubMed1998

Regulation of agr-dependent virulence genes in Staphylococcus aureus by RNAIII from coagulase-negative staphylococci.

Many of the genes coding for extracellular toxins, enzymes, and cell surface proteins in Staphylococcus aureus are regulated by a 510-nucleotide (nt) RNA molecule, RNAIII. Transcription of genes encoding secreted toxins and enzymes, including hla (alpha-toxin), saeB (enterotoxin B), tst (toxic shock syndrome toxin 1), and ssp (serine protease), is stimulated, while transcription of genes encoding cell surface proteins, like spa (protein A) and fnb (fibronectin binding proteins), is repressed. Besides being a regulator, RNAIII is also an mRNA coding for staphylococcal delta-lysin. We have identified RNAIII homologs in three different coagulase-negative staphylococci (CoNS), i.e., Staphylococcus epidermidis, Staphylococcus simulans, and Staphylococcus warneri. RNAIII from these CoNS turned out to be very similar to that of S. aureus and contained open reading frames encoding delta-lysin homologs. Though a number of big insertions and/or deletions have occurred, mainly in the 5' half of the molecules, the sequences show a high degree of identity, especially in the first 50 and last 150 nt. The CoNS RNAIII had the ability to completely repress transcription of protein A in an RNAIII-deficient S. aureus mutant and the ability to stimulate transcription of the alpha-toxin and serine protease genes. However, the stimulatory effect was impaired compared to that of S. aureus RNAIII, suggesting that these regulatory functions are independent. By creating S. epidermidis-S. aureus RNAIII hybrids, we could also show that both the 5' and 3' halves of the RNAIII molecule are involved in the transcriptional regulation of alpha-toxin and serine protease mRNAs in S. aureus.

Amino Acid Sequence↗

PubMed1986

Rapid lysostaphin test to differentiate Staphylococcus and Micrococcus species.

A rapid, simple lysostaphin lysis susceptibility test to differentiate the genera Staphylococcus and Micrococcus was evaluated. Of 181 strains from culture collections, 95 of 95 Staphylococcus strains were lysed, and 79 of 79 Micrococcus strains were not lysed. The seven Planococcus strains were resistant. Clinical isolates (890) were tested with lysostaphin and for the ability to produce acid from glycerol in the presence of erythromycin. Overall agreement between the methods was 99.2%. All clinical Micrococcus strains (43) were resistant to lysostaphin, and all clinical Staphylococcus strains (847) were susceptible. Seven of the Staphylococcus strains did not produce acid from glycerol in the presence of erythromycin. This lysostaphin test provides results in 2 h. It is easier to perform than previously described lysostaphin lysis methods. It is also more rapid and accurate than the glycerol-erythromycin test.

Bacteriological Techniques↗