Nosocomial Staphylococcus aureus is known as an important clinical pathogen in health care, hospital, and community settings. One of the serious threats associated with clinical isolates of Staphylococcus aureus is multi-drug resistance associated with integrons..
The objective of the present study was to investigate antimicrobial susceptibility patterns, frequency of class 1 and 2 integrons, and associated gene cassettes in different spa types of Staphylococcus aureus isolated from intensive care units (ICUs)..
During a five-month descriptive cross-sectional study, 80 Staphylococcus aureus strains isolated from hospitalized patients in ICU wards in five hospitals of Tehran, Iran were investigated. Staphylococcus aureus isolates were submitted to susceptibility testing and Polymerase Chain Reaction (PCR) to detect mecA gene, class 1 and 2 integrons, and associated gene cassettes. All the isolates were genotyped by staphylococcal protein A (spa) typing..
The overall prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) was found to be 86.2%. All the isolates were susceptible to vancomycin, teicoplanin and linezolid and resistant to penicillin and ampicillin. All the 80 Staphylococcus aureus isolates were observed to be multi-drug resistant. Class 1 and 2 integrons were commonly found in 56.3% and 18.7% of the isolates, respectively. Six different gene cassettes were detected in class 1 integron (aadA2, aadB, blaoxa, aacA4, cmlA6, and catB) and three were found in class 2 (dfrA1, aadA1, and sat2). Gene cassette arrays aadA, aadB, blaoxa, and aacA were common in the two integron classes of Staphylococcus aureus isolates. Five different spa types of t790, t030, t969, t7580 and t1425 were identified among our isolates where spa type t790 was the most predominant spa type among integron-bearing Staphylococcus aureus strains..
The present study reports on a high rate of multi-drug resistance, the predominance of the frequency of class 1 integron, and the emergence of spa type t790 among Iranian Staphylococcus aureus strains. The results revealed that the dissemination of multi-drug resistance among Staphylococcus aureus isolates may be associated with the presence of integrons. Therefore, continuous surveillance to monitor integrons and the associated gene cassettes among nosocomial pathogens, especially Staphylococcus aureus, is essential..

Staphylococcus aureus is the most important cause of nosocomial infections acquired in the community. Protein A is a major component of Staphylococcus aureus cell wall. In analysis of the nucleotide sequence Protein A encoding spa, locus x consists of 24 base pairs which repeat with high polymorphism. In this study, the spa gene of Staphylococcus aureus isolated from clinical specimens were obtained from patients admitted to the hospital and healthy carriers. In a cross-sectional study, a total of 200 samples were collected. One hundred fifty samples were obtained from hospitalized patients and 50 samples obtained from staff nasal swabs in Hamadan University Hospitals from October 2013 to August 2014. Disk diffusion antibiotic susceptibility tests performed. The antibiotics studied were Vancomycin (30 µg), Cefoxitin (15 µg) Gentamicin (10 µg), Tetracycline (30 µg), Trimethoprim/sulfamethoxazole (25 µg), Ciprofloxacin (5 µg), Erythromycin (15 µg), Clindamycin (2 µg), Rifampin (5 µg). The tests performed according to the guidelines of clinical and laboratory standards institute (CLSI). It also detect the mecA gene of Methicillin-resistant Staphylococcus aureus strains (MRSA) and genes spa which encodes the protein A by polymerase chain reaction (PCR). The PCR products using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method with enzyme Rsa I (Afa I) were prepared. This methicillin-resistant Staphylococcus aureus strain (MRSA) had the highest sensitivity and resistance to ciprofloxacin and clindamycin. Totally, 8 amplicon with different sizes for the spa gene were identified. A total of 9 patterns polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) were found. Some of these patterns between Staphylococcus aureus isolated from clinical specimens and nasal carriers were common. There is a similar pattern of spa gene among patients admitted to the hospital and staff, according to our findings. Analysis of the patterns can reduced transmission of infection in both hospital staff and patients. Also it can help the physicians for correct management of infections.

The prevalence of methicillin resistant Staphylococcus aureus (MRSA) and methicillin sensitive Staphylococcus aureus (MSSA) carriage among poultry and poultry farmers in Malaysia is largely unknown. In the current investigation، chickens and chicken farmers from 30 chicken farms were screened for MRSA and S. aureus carriage. The genetic characteristics of the isolates were determined through multi locus sequence typing (MLST)، Staphylococcus protein A (spa) typing and virulent gene profiling. The outcome of the study showed lack of MRSA and extremely low S. aureus prevalence (n=7 of 503، 1. 4%) among chicken flocks and the poultry farmers in Malaysia. Staphylococcus aureus isolates belonged to 4 sequence types (ST): ST97 (spa type t359)، ST1179 (t359)، ST 692 (t2247) and ST188 (t189). It can be concluded that MRSA/MSSA prevalence is very low among chicken and chicken farmers، human and chicken cross transmission of S. aureus does not seem to be a threat in Malaysia.

Extracts, herbal essential oil and natural ingredients have known antibacterial properties and can be used as food preservatives.  Quinoa seed is a rich source of protein with strong antioxidant and antibacterial properties than other cereals. The aim of this study was to investigate the antimicrobial activity of peptide extracted from quinoa on Staphylococcus aureus and Salmonella enterica bacteria.  To determine the optimal condition of the peptide hydrolysis with the best antimicrobial property was used pepsin and alcalase enzyme at different temperatures and times. Antibacterial effects of hydrolyzed peptide from quinoa proteins on two types of gram positive and negative bacteria (Staphylococcus aureus and Samunella antrica) were compared with the gentamicin antibiotic by Agar well diffusion method. The highest growth inhibition zone in Staphylococcus aureus and Salmonella enterica   were seen at enzyme activity 60 (Anson per kg protein), Temperature of 50, 150 minutes and 800 μg / ml concentration (13.13 ± 1.00 for Staphylococcus aureus and 11.00 ± 1.1 for Salmonella enterica). According to the findings, the peptide derived from protein quinoa has a good inhibitory effect on Staphylococcus aureus and Salmonella enterica bacteria. It is recommended that further research is done on the quinoa seed and its peptides be used as a natural preservative in foods.
 

Synovial fluid is composed of plasma ultrafiltration and hyaluronic acid secretion by synovial cells. Synovial fluid plays a role as softener and feeding cartilages without vessels. Infectious arthritis is one of the commonest arthritis and if the disease did not cure in the first days it would injure cartilages irreversibly. The goal of this study was identification of Staphylococcus aureus in synovial fluid of patients suspected to arthritis through PCR in Urmia city.
In this research synovial fluid contamination with Staphylococcus aureus and biochemical parameters such as the amount of glucose, protein and the number of white blood cells were studied. Amplification of nuc gene with the length of 279 bp using PCR method was applied to confirm Staphylococcus aureus isolation.
For this, 400 cerebrospinal fluid samples were tested from hospitalized patients with arthritis in two hospitals in Urmia city during 3 months, which out of them 109 of samples were contaminated with bacteria including: 78 of isolates were Staphylococcus aureus, 12 of them were coagulase negative Staphylococci, 4 of them were Streptococcus and 15 of them were gram negative bacilli. Also, results showed that the amounts of glucose in positive samples in comparison to the amount of glucose in synovial fluid were significantly decreased. The amount of protein and the number of white blood cells in synovial fluid of positive samples were significantly higher in comparison to normal synovial fluid.
Results showed that Staphylococcus aureus is the most common agent at infections arthritis, therefore it is recommended to use an experimental treatment for Staphylococcus aureus prior to final results.

The incidence of nosocomial Staphylococcus aureus infection is increasing annually and becoming a true global challenge. The pattern of Staphylococcus aureus protein A (spa) types in different geographic regions is diverse.
This study determined the prevalence of methicillin-resistant S. aureus and different spa types in S. aureus clinical isolates.
During a six-month period, 90 S. aureus isolates were recovered from 320 clinical specimens. The in vitro susceptibility of various S. aureus isolates to 16 antibiotic discs was assessed using the Kirby-Bauer disk diffusion method. Molecular typing was carried out with S. aureus protein A typing via polymerase chain reaction.
The frequency of methicillin-resistant S. aureus in our study was 88.9%. Twenty-three (25.5%) isolates were positive for panton-valentine leukocidin encoding genes. S. aureus presented a high resistance rate to ampicillin (100%) and penicillin (100%). No resistance was observed to vancomycin, teicoplanin, or linezolid. The rates of resistance to the majority of antibiotics tested varied between 23.3% and 82.2%. The rate of multidrug resistance among these clinical isolates was 93.3%. The 90 S. aureus isolates were classified into five S. aureus protein A types: t037 (33.3%), t030 (22.2%), t790 (16.7%), t969 (11.1%), and t044 (7.7%). Eight (8.9%) isolates were not typable using the S. aureus protein A typing method.
We report a high methicillin-resistant S. aureus rate in our hospital. Additionally, t030 and t037 were the predominant spa-types among hospital-associated S. aureus. Our findings emphasize the need for continuous surveillance to prevent the dissemination of multidrug resistance among different S. aureus protein A types in Iran.

Various virulence factors are involved in the pathogenesis of Staphylococcus aureus. Proteins that mediate adhesion to the host cell surface are important factors in the binding and invasion of Staphylococcus aureus. The aim of this study was to evaluate the frequency of genes encoding adhesion proteins FnbA, FnbB, Cna, Efb, Ica, Bbp < /em> and SdrE in Staphylococcus aureus strains in Ahvaz. In this study, 231 Staphylococcus aureus specimens were isolated from 4 hospitals in Ahvaz after biochemical tests. DNA was extracted by phenol-chloroform method and the frequency of cna, fnbA, fnbB, efb, ica, bbp < /em> and sdrE genes was determined using specific primers for each gene by Multiplex PCR. In this study 16srRNA was used as internal control. Finally, the PCR products were applied on acrylamide gel. The frequency of genes studied in this study were as follows: fnbB gene (67.53%), fnbA gene (53.24%), ica gene (51.94%), cna gene (40.25%), efb (37.66%), sdrE (26.40%) and bbp < /em> gene (11.68%). Based on this study, the variable frequency of pathogenic genes in clinical isolates of Staphylococcus aureus confirms that bacterial virulence factors play an important role in bacterial invasion and pathogenicity. Given the importance of Staphylococcus aureus in creating a wide range of diseases and the role of various adhesins produced by this mass, complete information on the distribution of the aforementioned adhesins among isolated strains in Iran is essential.

Staphylococcus aureus protein A، as a cell wall protein of the bacterium، belongs to a group of bacterial proteins with binding specificity for the IgG molecule. Recently، we cloned and expressed the protein A gene of Staphylococcus aureus in E. coli، as a fusion protein with maltose binding protein (MBP-Protein A). After purification، the expressed protein was also labeled with peroxidase. The aim of this study was to evaluate the reaction of this recombinant protein A with the immunoglobulin of some animal species. Based on the results of ELISA and immunodot، the labeled protein A was able to bind cat and dog IgGs. The reactivity of the protein with cattle and horse IgGs was weak and it reacted poorly with sheep IgG. This protein did not react with chicken IgG. In this study، the ability of the expressed protein A labeled with peroxidase، for detection of E. coli specific antibodies in cat and dog sera was demonstrated by indirect ELISA. In conclusion، the recombinant MBP-protein A is biologically active and could be used in immunological assays at least for certain animal species.

The aim of this study was to investigate the antibacterial effect of the recombinant camel Lactoferrampin-Lactoferricin on the growth rate of Staphylococcus aureus bacteria, one of the causes of mastitis in dairy cows. This peptide, which was prepared through a previous study in Biotechnology Laboratory of Animal Science Department, Faculty of Agriculture, Ferdowsi University of Mashhad. Antibacterial effects of this peptide was assessed by Count Colonies on Methicillin-resistant Staphylococcus aureus )PTCC 1764( and Staphylococcus aureus )ATCC 25923(. Heat resistance properties and freeze drying process of the peptide were evaluated by disk diffusion method in triplicate. The results showed that this recombinant peptide had an antibacterial effect on Staphylococcus aureus (p<0/0001), but had no effect on methicillin-resistant Staphylococcus aureus. Heat resistant of the recombinant peptide also showed that 100 °C temperature for 40 minutes had no significant effect on the anti-bacterial properties of this protein (p<0/0001). This protein showed no loss of activity after freeze drying process. The results obtained from this study proved the stable activity of natural peptides as well as antibacterial properties. This recombinant peptide can be used as an alternative to antibiotics or a therapeutic supplement to cure mastitis in dairy
cows.

Staphylococcus aureus is the causative agent of a high percentage of nosocomiallyacquired infections and food-borne illnesses. Antimicrobial resistance of S. aureus,especially methicillin-resistant S. aureus (MRSA), continues to be a concernfor cliniciansworldwide. The aim of this study was to investigate the effects of salt stress on the antimicrobialdrug resistance and protein profile of S. aureus. Staphylococcus aureus (ATCC 25823) was grown in trypticase soybroth at 37°C. Cells in the exponential growth phase were gradually exposed to sub-lethalsalt stress with concentrations ranging from 5% to35% (wt/vol). There after, these cells wereharvested and re-suspended in a tube containing 0.5mL of saline. To standardize the numberof bacteria, the bacterial suspension was compared to the 0.5 McFarland standard suspension.Antibiotic susceptibility was determined using the disk diffusion method, andthe method involved plating of cell suspensions with stressed cells and unstressed cells onMueller-Hinton agar plates. The pooled proteins from each condition were analyzed usingsodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Compared to the unstressed cells, the cells exposed to salt showed significantchanges in resistance to rifampicin (P=0.032), penicillin (P=0.02) and methicillin(P=0.001). Furthermore, SDS-PAGE analysis of pooled proteins from cells exposed to saltshowed changes in the protein profile. We conclude that salt stress is responsible for the changes in protein profileandantimicrobial resistance of S. aureus, especially to methicillin.