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PubMed1969

Biochemical characterization of lysine auxotrophs of Staphylococcus aureus.

Lysine biosynthesis in Staphylococcus aureus has been studied by use of a series of lysine auxotrophs. The strains were isolated after chemical mutagenesis. The majority of these mutant strains were classified according to the enzymatic step found to be deficient. Specific enzyme assays as well as nutritional tests were used to group the organisms. The enzymes included were dihydrodipicolinate synthetase, dihydrodipicolinate reductase, diaminopimelate epimerase, and diaminopimelate decarboxylase. The accumulation of diaminopimelate in certain mutants and the demonstration of dihydrodipicolinate synthetase and reductase provide the first detailed evidence that S. aureus utilizes the diaminopimelate pathway for lysine biosynthesis. A cell-free system was used to study the regulation of these enzymes with the exception of diaminopimelate epimerase. Lysine repressed all of the enzymes tested. The repression appeared to be coordinate in nature. The data presented provide suggestive evidence that the lysine biosynthetic region in S. aureus constitutes an operon.

Carboxy-Lyases↗
PubMed1979

The pathogenetic role of Staphylococcus aureus in primary human glomerulonephritis.

Antibody levels to a cell product of Staphylococcus aureus, antistaphylolysin antibody (AStaL), were determined in the sera of 185 patients with various renal diseases using the hemolysis inhibition test. Detection of Staphylococcus aureus antigen in renal biopsy specimens was performed by the immunofluorescent technique. Elevated AStaL values were observed in eleven patients. In four of them, Staphylococcus aureus antigen was clearly detected in the glomerular mesangial area associated with deposits of immunoglobulins and complement. Most of these patients showed marked elevation of AStaL values with low serum complement levels and had diffuse proliferative glomerulonephritis. These results suggest that Staphylococcus aureus may act as a specific antigen and play an important role in the pathogenesis of primary human glomerulonephritis.

Antibodies, Bacterial↗
PubMed2005

Evaluation of PCR primers from putative transcriptional regulator genes for identification of Staphylococcus aureus.

AIMS: To examine if PCR primers derived from putative transcriptional regulator genes can be useful for Staphylococcus aureus identification. METHODS AND RESULTS: Staphylococcus aureus gene sequences that encode transcriptional regulators were retrieved from GenBank and compared with other DNA sequences via BLAST searches. Two uniquely present, putative transcriptional regulator genes (i.e. Sa0836 and Sa0856) were selected as a consequence and PCR primers (Sa0836F/R and Sa0856F/R) were then designed from these genes for evaluation. A total of 84 bacterial strains/isolates including 23 Staph. aureus, 18 nonaureus Staphylococcus and 43 other common bacterial isolates were examined. The results indicated that PCR primers from Sa0836 and Sa0856 recognized genomic DNA from Staph. aureus only, but not from other non-aureus Staphylococcus or common bacteria. CONCLUSIONS: PCR detection of the putative transcriptional regulator genes Sa0836 and Sa0856 represents a useful means of identifying Staph. aureus from other bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: The existence of species-species transcriptional regulator genes may be a common phenomenon in bacteria. Besides their value as novel diagnostic markers, further investigation on the putative transcriptional regulator genes Sa0836 and Sa0856 and their related products may shed light on the molecular mechanisms of Staph. aureus adaptation and virulence.

Bacteriological Techniques↗
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↗
PubMed1992

[Incidence, frequency and resistance characteristics of methicillin-oxacillin resistant Staphylococcus aureus strains in Germany].

In a multicentre study, the methicillin-resistant Staphylococcus aureus (MRSA) isolates in 19 large clinics in Germany were recorded, and the resistance characteristics of these strains were studied. Oxacillin-mannitol-salt agar plates were distributed to all participants to ensure uniformity of screening, and each laboratory used these plates to investigate 200 consecutive Staphylococcus aureus isolates for oxacillin-methicillin resistance. Of the 3,794 evaluable Staphylococcus aureus isolates, 71.5% were penicillin and 3.7% (142) oxacillin resistant; four study centres reported methicillin-oxacillin resistance rates of more than 5%. Of the MRSA isolates, 75% were also resistant to ciprofloxacin, 61% to fosfomycin, 52% to imipenem, 50% to trimethoprim/sulfamethoxazole and 36% to clindamycin. All isolates were sensitive to vancomycin and teicoplanin. Of the Staphylococcus aureus strains isolated from patients in intensive therapy units, 10.4% were methicillin-oxacillin resistant. Drains and catheter tips (9.8% and 5.2% respectively) were the materials with the highest proportions of MRSA. Of the MRSA isolates in this study, 58.2% belonged to lysis group II.

Ciprofloxacin↗
PubMed2003

Prevalence of methicillin resistant Staphylococcus aureus in Karnataka.

This study was undertaken to find out the prevalence of methicillin resistant Staphylococcus aureus (MRSA) infection in our hospital and to compare their antibiotic susceptibility pattern with methicillin sensitive Staphylococcus aureus (MSSA). 100 strains of Staphylococcus aureus isolated from various clinical samples were screened for MRSA by disc diffusion method using 1 gm oxacillin disc. Antibiotic sensitivity testing was done by Kirby-Bauer's disc diffusion method. Out of these, 43% were identified as MRSA and the remaining 57% were MSSA. There was a marked difference in antibiotic sensitivity pattern of these M RSA versus the MSSA isolates. None of the MRSA isolate was found to be sensitive to amoxycillin while 36.8% of MSSA were sensitive to this antibiotic. 9.3%, 18.6%, 34.9% and 95.3% of MRSA were sensitive to cotrimoxazole, cloxacillin, ciprofloxacin and chloramphenicol, while 75.4%, 92.9%, 91.2% and 94.7% of MSSA were sensitive to these antibiotics respectively. Sensitivity to macrolide group of antibiotics like erythromycin and roxithromycin were seen in 7% and 14% of MRSA in comparison to 85.9% and 91.2% of MSSA respectively. Amongst the aminoglycosides like gentamicin and amikacin, the sensitivity of MRSA was found to be 18.6% and 46.5% and that of MSSA was 98.2% and 94.7% respectively. Sensitivity to cephalosporins like cephalexin and cefotaxime was seen in 23% and 25.5% of MRSA, whereas 100% of MSSA were sensitive to these antibiotics. All Staphylococcus aureus isolates were found to be uniformly sensitive to vancomycin. Majority of the isolates belonged to phage group III and the common phage types were 54, 54/75 and 54/75/85.

Humans↗
PubMed1970

Stability of neomycin resistance in Staphylococcus aureus.

A strain of Staphylococcus aureus isolated from the skin of a subject with eczema showed a loss in resistance to neomycin and tetracycline after treatment with neomycin was stopped. Seven out of 22 strains of neomycin-resistant Staph. aureus showed a loss in resistance to neomycin and streptomycin after storage in nutrient broth for 14 days at room temperature, and it seems probable that resistance in these unstable strains was controlled by extrachromosomal elements or plasmids. Strains of phage types 84/85 and 29/77 and related types were frequently isolated in general hospital wards and showed no loss in resistance on similar storage in nutrient broth. Five of the neomycin-unstable strains were isolated from patients with eczematous lesions. Multiple-resistant and antibiotic-sensitive strains of Staph. aureus of similar phage type were isolated from patients in a ward for patients with skin disease, and the possibility of transfer of resistance in vivo is discussed.

Drug Resistance, Microbial↗
PubMed1983

[Purulent Staphylococcus aureus meningitis].

Retrospective study of 14 cases of Staphylococcus aureus meningitis and of data from the literature shows that this as yet infrequent disease which carries a high mortality rate (40%) is always related to neurosurgery, primary or iatrogenic septicemia, or local infection, usually in the lumbar area (spinal, abscess, spondylitis). The major clinical problem is the search for the meningeal lead point of Staphylococcus aureus penetration, whose eradication is more essential than in usual bacterial meningitis. Prognosis is mainly dependent upon the eventual existence of associated severe septicemia. Antibiotics active on Peni-M resistant Staphylococcus aureus and meningeal infection are reviewed.

Adult↗
PubMed1975

Effect of lincomycin on lipase formation by Staphylococcus aureus.

The production of Staphylococcus aureus lipase could be inhibited by addition of 0.1 mug/ml lincomycin to the media without affecting growth. Addition of the same amount of drug at various stages of growth inhibited further enzyme production. The enzymatic activity of the lipase could not be inhibited at a concentration of 2.5 mug/ml lincomycin.

Enzyme Activation↗
PubMed1975

Induction of mutation in Staphylococcus aureus by ethylmethane sulphonate.

Staphylococcus aureus strains were treated with ethylmethane sulphonate with the object of obtaining mutants that differed from the wild type in one of the properties that might contribute to virulence. Mutants with isolated loss or deficient production of gamma-haemolysin, coagulase, leucocidin and staphylokinase were obtained. Changes in more than one property were often observed. The loss of delta-lysin production was always coupled with an appreciable reduction in P-V leucocidin production. With that exception, systematised combined loss of a restricted number of staphylococcal characteristics was not observed. Mutants that had lost all characteristics of S. aureus were phage-resistant. Isolated loss of staphylokinase production and deficient P-V leucocidin production were found to be due to the independent loss of two prophages.

Animals↗
PubMed2004

Two cases of fatal shock after transfusion of platelets contaminated by Staphylococcus aureus: role of superantigenic toxins.

We detected Staphylococcus aureus superantigenic toxins in the platelet infusion bags that had been used for 2 patients who subsequently developed transfusion-associated Staphylococcus aureus infection. Both patients, who were immunodeficient, developed manifestations of toxic shock syndrome and septic shock, and they died soon after the onset of infection.

Aged↗
PubMed2004

Ciprofloxacin and levofloxacin resistance among methicillin-sensitive Staphylococcus aureus isolates from keratitis and conjunctivitis.

PURPOSE: The majority of Staphylococcus aureus isolated from ocular infections are methicillin sensitive (MSSA). Fluoroquinolone resistance among methicillin- resistant Staphylococcus aureus is well known but not among MSSA. In this study we investigate the emergence of fluoroquinolone (ciprofloxacin, levofloxacin) resistance among methicillin-sensitive Staphylococcus aureus isolates from keratitis and conjunctivitis. DESIGN: Cross-sectional study. METHODS: Minimal inhibitory concentration susceptibility profiles for 1230 S. aureus isolates from keratitis and conjunctivitis were analyzed. Historical and current rates of emerging fluoroquinolone resistance for methicillin-resistant (MRSA) and methicillin-sensitive isolates (MSSA) were evaluated. Sensitivity patterns for vancomycin and gentamicin were also documented. RESULTS: Ciprofloxacin resistance among corneal and conjunctival S. aureus isolates during the first 6 years after its introduction (baseline) (1990-1995) was 8% and ranged from 3% to 11%. The rate for the most recent 6 years (current) (1996-2001) was 20.7%. Baseline ciprofloxacin resistance for MSSA isolates was 2% vs 55.8% for MRSA. The current resistance rate for MSSA is 5% vs 83.7% for MRSA. The general resistance rate from January 2000 to December 2001 for levofloxacin was 25.5% vs 33.2% for ciprofloxacin (P =.13). The levofloxacin-resistance rate for MSSA was 4.7% vs 11.9% for ciprofloxacin (P =.05). In MRSA isolates, a higher resistance rate was found for ciprofloxacin (95.7%) vs levofloxacin (82.1%) (P =.04). No resistance for vancomycin was documented for any of the S. aureus isolates. Gentamicin susceptibility for MSSA was 99% and MRSA was 86%. CONCLUSIONS: Ciprofloxacin and levofloxacin resistance among methicillin-sensitive S. aureus corneal and conjunctival isolates is increasing. This is of concern because it narrows treatment choices for the management of these common ocular infections.

Anti-Infective Agents↗
PubMed1968

Chromosome mapping in Staphylococcus aureus.

The genome of Staphylococcus aureus was mapped by enumerating mutants induced by nitrosoguanidine during synchronous chromosomal replication following release from phenethanol inhibition. Both chromosomal replication time and cell division time were 120 min for this strain of S. aureus. Duplication of genes occurred within a 10-min period of the 120 min required for chromosomal replication. A high-resolution method was devised to determine the gene order of four genes that duplicated in the same 10-min interval of replication of the chromosome. A genomic map locating the positions of 10 genes was derived.

Cell Division↗
PubMed1975

Intrinsic and chemically produced microheterogeneity of Staphylococcus aureus enterotoxin type C.

Staphylococcus aureus enterotoxins C1 (SEC1) and C2 (SEC2) produced from 50-liter quantities of crude culture supernatants were purified chromatographically in a neutral or acid milieu. Microheterogenity of SEC1 was markedly increased by treatment of the purified toxin with alkali, and new more acidic charged species appeared. SEC2 was more heterogenous than any of the other S. aureus enterotoxins and was affected only slightly by treatment with alkali. Prolonged incubation of the organism during production of the SEC2 produced changes in charged species that may be related to a bacterial deamidase, since similar changes were not seen with alkaline treatment of the purified toxin. Although SEC1 and SEC2 showed complete identity immunologically, they are separate, distinct toxins, and alkali treatment of SEC1 did not produce SEC2.

Alkalies↗
PubMed1975

Trypsin-mediated activation of the alpha-haemolysin of Staphylococcus aureus.

Alpha protoxin of Staphylococcus aureus "Wood 46" was activated by trypsin which had been coupled to carboxymethylcellulose, as indicated by the toxin's ability to hydrolyse tosyl-arginine methylester (TAME). A Lineweaver-Burk plot of the degradation of TAME by toxin and trypsin showed that toxin had a greater affinity for the substrate than had trypsin. N-terminal amino-acid analyses of activated toxin suggested that leucine or isoleucine is the N-terminus, in contrast to protoxin, the N-terminus of which is histidine.

Amino Acid Sequence↗
PubMed1971

Chemical characterization of a new surface antigenic polysaccharide from a mutant of Staphylococcus aureus.

A mutant of Staphylococcus aureus H was isolated by virtue of its inability to agglutinate with antibodies against teichoic acid of S. aureus. Immunological studies revealed that the mutant, S. aureus T, possessed a new surface antigen in addition to having the antigenic determinant of the wild-type strain, the ribitol teichoic acid. The presence of this additional surface component rendered strain T resistant to staphylococcal typing phages, presumably by masking the phage-receptor sites. The polymer was separated from teichoic acid by chromatography on diethylaminoethyl cellulose and was shown to be composed of two amino sugars, N-acetyl-d-fucosamine and N-acetyl-d-mannosamin uronic acid.

Agglutination Tests↗