Showing 32 results for Staphylococcus Aureus
Sh Jalalpoor,
Volume 4, Issue 2 (10-2010)
Abstract
Bachground and objectives: Hospital surfaces can serve as reservoirs of potential pathogen bacteria. Staff hands are the most important source of transmission in hospital. The prevalence of β–lactamase producer bacteria in staff hands and hospital surfaces, increase antibiotic resistance nosocomial infection. The aim of this study was to survey the spread of beta-lactam resistance Staphylococcus sp. in Al-zahar hospital in Isfahan. Material and Methods: The research was carried out during 2005-2007 years in Al-zahra hospital in Isfahan. Overall, 274 samples (194 strains from surface and 80 strains from staff hands).The surface samples collected by using swab in Nutrient Broth (NB) and staff hand samples collected using Finger Print method. Bacterial identification was performed by Bacteriological methods, β–lactamase production by acidimetric method and antibiogram pattern by Kirby Bauer method. Results: Of 194 strains isolated from hospital surfaces, 105 (53.7%) strains, and of 80 strains isolated from staff hands, 28 (35%) are related to Staphylococcus sp. According to acidimetric test, 79.8% of S.aureus strains and 68.55% of S.epidermidis strains produce β-lactamase. Conclusion: Results show high frequency of antibiotic resistance and β– lactamase producer Staphylococcus sp. on staff hands and hospital surfaces. Reduction of bacteria in these sources is the most important manner to control transfer of virulence agents in bacteria and create of antibioticresistant strains. Key words: Staphylococcus aureus, Staphylococcus epidermidis, β– lactamase, Antibiotic-resistant, Hospital surfaces, staff hands.
Teyhoo M, Mobin H, Mozafari N A, Moadab S R, Sedigh Bayan Kh, Mones Rast Sh,
Volume 5, Issue 1 (4-2011)
Abstract
Abstract Background and objectives: Staphylococcus aureus is one of the most important etiological agents of hospital and community acquired infections. The enterotoxins and toxin shock syndrome toxin (TSST-1) are among the most common virulent determinants of this bacterium. They are also well-known for their super-antigenic properties. The incidence of TSST-1 producing strains is also very alarming. The aim of this investigation was to survey the prevalence of TSST-1 gene in the clinical isolates of S. aureus recovered from hospitalized patients in Shohada hospital of Tabriz, Iran. Material and Methods: During one year period, 1454 specimens obtained from hospitalized patients were investigated. After doing Isolation and purification, the isolates were identified by routine bacteriological methodologies.Their antibiotic susceptibility patterns were determined by agar disk diffusion method. Following genomic DNA extraction by boiling method, the presence of TSST-1 gene was analyzed by PCR. Results: A total 100 S. aureus isolates were recovered (6.87%). Antibiogram results indicate that all of the isolates are sensitive to linzolid 83% of them are resistant to meticillin. The prevalence rate of TSST-1 gene in the isolates is 20%. Conclusion: The high prevalence of TSST-1 gene in studied S. aureus strains and their circulation in the community can have a potentially alarming effect on general health of community. Key words: Staphylococcus aureus, TSST-1, Antibiotic resistance, PCR
Mousazade Moghadam M, Babavalian H, Mirnejad R, Shakeri F,
Volume 6, Issue 1 (4-2012)
Abstract
Abstract
Background and objectives: Genomic DNA extraction of bacterial cells is of processes performed normally in most biological laboratories therefore, various methods have been offered, manually and kit, which may be time consuming and costly. In this paper, genomic DNA extraction of Staphylococcus aureus was investigated using some laundry detergent brands available in Iran to achieve a rapid and cost effective method.
Material and Methods: five-enzyme Taj brand, three-enzyme Saftlan brand ,and Darya and Pak brands without enzyme were used in the concentrations of 10, 20, 40, 80 mg/L. Afterwards, in order to evaluate the efficiency of extracted DNA in downstream processing, PCR test was performed for femA gene in the genome of Staphylococcus aureus.
Results: DNA extraction using different concentrations of the brands show that extracted DNA using 40 mg/L Saftlan and Taj brand powders have the best results according concentration (µg/ml) and purity (A260/A280) parameters. These parameters are 387.5 1.88 (Taj), 254.1 2.80 (Softlan), 396.6 1.95 (Manual) and 423.3 2.2 (Kit), respectively. Afterward, the PCR test results by show that DNA extraction using laundry detergents has no effect on its efficiency in order to be used in downstream processes.
Conclusion: These results indicate that the proper concentrations of laundry detergents can be used to extract genomic DNA with similar efficiency to kit and manual extraction methods.
Key words: Bacterial genome, DNA extraction, laundry powder, PCR, Staphylococcus aureus
Ma Mansourighiasi, A Nasrollahiomran, M Hashemi, P Rajab Zadekanafi, M Jahangiri Rad Manjili,
Volume 7, Issue 1 (4-2013)
Abstract
Abstract
Background and Objective:Staphylococcusaureus is one of the important factors causing nosocomial infections. Typically 25-30 percent of healthy people carry the bacteria in their anterior nasal cavity. The physicians(50%), nurses (70%) and hospital staff (90%) are the carriers of this bacteria, leading to the infection of inpatients. The emergence of antibiotic-resistant Staphylococcus strains to vancomycin and methicillin has brought about several problems in treatment of the infections caused by Staphylococcus strains. Hence, we aimed to study the frequency of staphylococcus aureus carriers and resistance pattern among medical personnel of the surgical ward in ShahidRajaee hospital, Tonekabon.
Material and Methods: this analytic-descriptive study was conducted on the samples taken from nasal carriage of medical staff of surgical ward (N=120). Antibiotic- resistant of Staphylococcus strains was assessed by antibiogram and disk diffusion (DAD), in accordance with CLSI standards.
Results: of 34 (28.33%) who are nasal carriers of staphylococcus, 12 are over 30 years old and 24 under 30. Based on antibiogram, 1.97% of specimens are sensitive to Gentamicin and Co-trimoxazole, 1.94% to Ciprofloxacin, 2.88% to Vancomycin and 6.20% to Methicillin. In addition, 100% of specimens are resistant to Ampicillin, 1.97% to Penicillin and 2.88% to Amoxicillin. Four isolates areresistant,both to methicillin and vancomycin.
Conclusion:In this study, the spectrum of S. aureus resistant and sensitive strains to some antibiotics is similar to other studies, but a dramatic increase is seen in the rate of MRSA and non-susceptible cases to vancomycin. The Effectiveness of Penicillin, Amoxicillin and Ampicillin is still very low on S. aureus samples.
Key words: Prevalance Resistance Pattern, Staphylococcus aureus, Medical Staff, Nasal Cavity, Tonekabon
F Sadighian, Z Abedian, A Saane-Ei, Z Mirkarimi,
Volume 7, Issue 3 (10-2013)
Abstract
Abstract
Background and Objective: Nowadays, nosocomial infection is one of the greatest problems in hospitals. Normal flora of staff’s hands and the bacterial agents on the surface of medical equipment can become progressively colonized with potential pathogens during patient care. This study was carried out to determine the bacterial agents existed on staff’s hands and in the wards of hospital to step in to control nosocomial infection.
Material and Methods: In this descriptive study, during 17 months (22.mar.2010- 30.aug.2011), 403 samples, using sterile swab , were randomly obtained from the staff’s hands and medical equipment of emergency departments , ICU, male operation room and female surgical unit . The samples were cultured on Blood agar (BA) and Eosin methylene blue (EMB). Then, identification of isolated bacteria was done with diagnostic tests.
Results: Of 430 samples, 530 bacteria were isolated from staff’s hands (N= 291) and medical equipment (N= 234). The most common bacterium from personnel’s hands (144 49.5%) and medical equipment (24 10%) is Staphylococcus aureus. Also, three isolates of pseudomonas aeruginosa from staff’s hands of male surgical ward and medical equipment of ICU, and two isolates of Acinetobacter.spp from ICU’s medical equipment were identified.
Conclusion: With regard to the findings, it seems that applying the appropriate disinfectant agents by using standard procedures is necessary.
Keywords: Medical Equipment Staff’s Hand Nosocomial Infection Staphylococcus Aureus
T Dadgar, E Ghaemi, N Bahador, A Imani Fooladi, F Kamareie,
Volume 7, Issue 5 (2-2014)
Abstract
Abstract
Background and Objective: The main cause of spreading staphylococcal infections among patients is the healthy carriers working in hospitals. With the secretion of different sorts of toxins such as entrotoxin, this bacteria can provide the conditions for attacking on the host. The main objective of this study is identification of the characteristics and differences in the Staphylococcus aureus isolated from healthy carriers and from the patients on the basis of enterotoxin genes (sea-see).
Material and Methods: One hundred and twenty of the patients and 80 of healthy carriers worked in health centers of Gorgan, north of Iran, were investigated for S. aureus isolate. The isolates were evaluated by PCR for Enterotoxin Genes A-E (SEA to SEE).
Results: Enterotoxin genes (SEA to SEE) was found in 87.5% of the total isolates and the most frequent one was enterotoxin gene sea (N= 124). The prevalence of these isolates in healthy carriers was significantly higher than those of the patients.
Conclusion: Based on the results, the high percentage of S. aureus isolated from clinical samples contains enterotoxin genes. Therefore, Human as the source and carrier of S. aureus is paramount importance, which is due to significant relationship between being toxigenic strains and the source of isolation.
Key words: Staphylococcus Aureus Enterotoxin Patient Carrier
M Hasannejad Bibalan, N Javid, M Samet, F Shakeri, Ea Ghaemi,
Volume 8, Issue 3 (8-2014)
Abstract
Abstract
Background and Objective: Biofilm is a complex microbial community embedded in a self-produced extracellular polymeric matrix. We aimed to study the extent of biofilm formation by S. Areas isolates and its relation to some phenotypic and genotypic criteria.
Material and Methods: One hundred-fifty strains of Staphylococcus aureus isolated from Gorgan were studied. Microtiter plate assay method was used for investigation of biofilm formation.The biofilm formation of strains were recorded and its relation to accessory gene regulator (agr) and antibiotic resistance were assessed by X2 test.
Results: Eighty-four isolates (56%) were able to form biofilm. The strength of biofilm formation in agr group I was more than that of other groups. The biofilm formation among S. Areas isolated from the wound and urine (both with 75 %) had the highest capability. Methicillin-resistant isolates had a greater ability to biofilm formation.
Conclusion: Methicillin resistant isolates had a greater ability to biofilm formation. Given the importance and treatment related problems of Methicillin-Resistant Staphylococcus Aureus (MRSA) especially Community Acquired-Methicillin-Resistant Staphylococcus Aureus (CA-MRSA), it is a necessity to control or remove the biofilm formation alongside antibiotic treatment.
Keywords: Staphylococcus Aureus, Biofilm, Microtiter Plates Assay, PCR
Saadat, S, Solhjoo, K, Norouz-Nejad, Mj, Kazemi, A, Erfanian, S, Ashrafian, F,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Background and Objective: Vancomycin is used for treatment of methicillin-resistant S. Aureus (MRSA) infections therefore, resistance to this antibiotic is increasing. We aimed to determine the antibiotic resistance pattern and frequency of vancomycin resistant S. Areas (VRSA) strains isolated from clinical samples. Material and Methods: In this cross-sectional study, 100 S. Aureus isolates collected from hospitals in Shiraz during six months, 2012, were identified by biochemical, microbiological and molecular methods. After determination of antibiotic susceptibility pattern by disc diffusion method and vancomycin agar screening test, Minimum Inhibitory Concentration (MIC) was determined by E-test for vancomycin, thicoplanin, linezolid and quinupristin-dalfopristin. Results: The most resistant and the most sensitive antibiotic were ampicillin (%95) and quinupristin-dalfopristin (99%), respectively, and 44% of isolates were resistant to methicillin. In agar screening test, 48% of strains had reduced sensitivity and in disc diffusion 3% strains were resistant to vancomycin. In E-test method, only one isolate was resistant to vancomycin. Conclusion: given the presence of VRSA and new antibiotic resistant strains, we recommend doing some intervention to prevent from spreading these strains in hospitals. . Keywords: Clinical Specimens, Staphylococcus Aureus, Vancomycin, Antibiotic Resistance
Zare, Z, Solhjoo, K, Norooznejad, Mj, Kazemi, A,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract
Background and Objective: Increasing prevalence of methicillin resistant Staphylococcus aureus strains (MRSA) with their multidrug resistance potential causes difficulties in the treatment of infections due to these bacteria. Hence, the detection and determination of the frequency of MRSA strains via phenotypical and molecular methods is necessary in different parts of the county.
Material and Methods: In this cross- sectional study, 150 Staphylococcus aureus strains were collected from different clinical samples in the hospitals located in Shiraz and Jahrom, Iran. To detect methicillin resistant Staphylococcus aureus strains, we used phenotypical methods such as disc diffusion and minimum inhibitory concentration by E-Test, and PCR molecular method for mass gene.
Results: The frequency of methicillin resistant Staphylococcus aureus was 63 strains (42%) using disc diffusion and E-Test. while in PCR method, in addition to 63 strains, nine other isolates, which were sensitive to oxacillin by disc diffusion and E-Test, possessed also mecA gene. By and large, 72 isolates (48%) had methicillin resistance gene.
Conclusion: Given the results of phenotypical and molecular methods, the frequency of methicillin resistant Staphylococcus aureus was relatively high in this area. Thus, the MRSA strains can be detectable as soon as possible by accurate and sensitive methods such as PCR to determinate the effective antibiotics.
Keywords: Methicillin Resistant Staphylococcus Aureus, MRSA, MecA Gene, PCR
Amini, M, Hosseini Doust, Sa, Mohabati Mobarez, A,
Volume 8, Issue 5 (1-2015)
Abstract
Abstract Background and Objective: Staphylococcus aureus have been isolated frequently from the infection of blood, skin and soft tissue, and is one of the causative agents of food-borne illnesses. The purpose of this study was to investigate the occurrence of vanA in raw meat samples in Tehran, Iran. Material and Methods: Totally, 119 samples of chicken and turkey raw meat were cultured for Staphylococcus aureus. The Resistance to vancomycin was determined and Van A Gene detected by PCR method. Results: twenty- nine strains of Staphylococcus aureus were isolated. Of these, 14 (48.5%) were fully resistant to vancomycin and six of them had van A gene. Conclusion: Given that a large number of the samples were infected to VRSA and diversity of quality in production and distribution of foods and meat, the results could be varied. To avoid the transmission of antibiotic resistance chain to human, we should pay attention to make regulation and health conditions in production and distribution. Keywords: Staphylococcus Aureus, Vancomycin Resistance, Van A, Turkey Raw Meat, Chicken
Sadeghi, M, Amini, A, Behnampour, N, Ghasemi, Sm, Arefian, A., Mohajer, S,
Volume 9, Issue 2 (7-2015)
Abstract
Background and Objective: Staphylococcus aureus is an important cause of food poisoning. Due to the high consumption of fruit and ice cream in summer, this study aimed to determine the prevalence of S. aureus in traditional ice cream and juice in Gorgan, Iran.
Material and Methods: This cross-sectional study was conducted on 25 places selling traditional ice cream and juice in the summer of 2014 in Gorgan, Iran.
Results: Results showed that the microbial contaminants in traditional ice cream and juice centers were 56% and 14.28% of S. aureus, 44% and 33.3% of yeast, 28% and 28.57% of B. cereus, 12% and 4.76% of Listeria, 8% and 14.28% of Bacillus subtilis and 4% and 4.76% of Bacillus licheniformis ,respectively.
Conclusion: The findings of this study indicated a high contamination of traditional ice cream and juice with Staphylococcus aureus and various microorganisms.
Keywords: Ice Cream, Food Contamination, Staphylococcus Aureus
Razaz Rahmati, N, Mohabati Mobarez, A, Khoram Abadi, N, Sharifzade Peyvasti, V, Shokoohizade, L,
Volume 9, Issue 2 (7-2015)
Abstract
Background and Objective: Vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) are the leading nosocomial pathogens in Iran. We aimed at evaluating the resistance patterns of Staphylococcus aureus and enterococci to the antibiotics recommended by Clinical and Laboratory Standards Institute (CLSI).
Material and Methods: Two-hundred forty Staphylococcus aureus and 203 Enterococcus isolated from urine, wound, blood, trachea, stool and other clinical specimens of inpatients and outpatients were obtain from some hospitals in Tehran. Sensitivity of S. aureus to oxacillin, vancomycin, chloramphenicol, nitrofurantoin, erythromycin, clindamycin and linezolid were determined by disk diffusion according to CLSI (M100-S22) guidelines. Likewise, sensitivity of enterococci to ampicillin, vancomycin, teicoplanin, tigecycline, linezolid, tetracycline, chloramphenicol and nitrofurantoin was invesditated by the same method.
Results: Of 240 S. aureus isolates, 56%, 46.6% and 40.4%were resistant to oxacillin, erythromycin and clindamycin, respectively. We found one S. aureus isolate with low susceptibility to vancomycin (VISA; 0.5%). All S. aureus isolates were sensitive to chloramphenicol, nitrofurantoin and linezolid. Of 203 Enterococcus spp., 47.3%, 24.6%, 9.4%, 85.2%, 11.3% and 4.4% were resistant to ampicillin, vancomycin, teicoplanin, tetracycline, chloramphenicol and nitrofurantoin, respectively. All these isolates were sensitivity to tigecycline and linezolid.
Conclusion: Resistance of S. aureus isolates to oxacillin, erythromycin and clindamycin was significant. Enterococci isolates were remarkably resistant to ampicillin, vancomycin, teicoplanin, tetracycline, chloramphenicol and nitrofurantoin. Given our results, we suggest vancomycin, chloramphenicol, linezolid and nitrofurantoin for S. aureus infections and tigecycline and linezolid as drugs of choice for enterocoocal infections treatment.
Keywords: Staphylococcus aureus, Enterococcus, Tehran, Hospitals
Behshood, P, Karbasizade, V, Naghavi, Ns,
Volume 9, Issue 2 (7-2015)
Abstract
Background and Objective: Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen involved in nosocomial infections. Because of increasing antibiotic resistance of these strains, treatment of these infections has become very difficult. This study aimed to determine the frequency and drug resistance pattern of MRSA isolates from nosocomial infections in hospitals.
Material and Methods: the isolates of S.aureus (n= 100) isolated from clinical samples such as: urine, blood, wound, throat, sputum, cerebrospinal fluid, catheter and other purulent discharge from in patients were identified using biochemical tests. MRSA strains were isolated by using agar screening method and then drug resistance pattern of them was determined by disk diffusion method.
Results: Out of 100 S.aureus strains, 65 (65%) were MRSA. Drug resistance of MRSA isolates to most antibiotics were high: penicillin100%, oxacillin 100%, nitrofurantoin 80%, tetracycline 63%, erythromycin 58.4%, gentamicin 46.1%, clindamycin 33.8%, cotrimoxazole 35.3% and ciprofloxacin 26.1%. Also 35 of MRSA isolates were multiple drug resistance (MDR).
Conclusion: The prevalence of MRSA isolates and also their resistance to other antibiotics were high.
Keywords: Drug Resistance, Methicillin-Resistant Staphylococcus Aureus, Multi-Drug Resistant
Izadpanah, Mr, Asadpour, L,
Volume 9, Issue 3 (9-2015)
Abstract
Abstract
Background and Objective: Staphylococcus aureus is an important opportunistic pathogen causing a wide range of infections in human .Most clinical isolates of S.aureus are resistant to a number of antibiotics. For appropriate antimicrobial therapy, this study was conducted to determine antibacterial drug resistance patterns of S.aureus isolates obtained from different clinical samples in Rasht.
Material and Methods: the clinical isolates of S.aureus were collected from different clinical laboratories in Rasht. Thirty coagulase positive S.aureus strains were identified using biochemical tests and amplification of 23SrRNA and coa genes by polymerase chain reaction. Finally, the resistance pattern of the isolates to 16 selected antimicrobial agents was evaluated by disk diffusion method.
Results: the S.aureus isolates (75%) were resistant to methicillin and all of them were multidrug resistance. The isolates were high resistance to ampicillin (73%), amoxicillin (60%), cloxacillin (53%) and low resistance to vancomycin (7%) and gentamicin (10%).
Conclusion: given the high prevalence of methicillin resistant, multi drug resistant and presence of vancomycin resistant S.aureus isolates in Rasht, continuously monitoring of drug resistance pattern of S.aureus isolates is recommended for having appropriate therapeutic regime.
Keywords: Staphylococcus Aureus, Coagulase, Drug Resistance, PCR
Hadi Koohsari , Ezzat Allah Ghaemi , Nour Amir Mozaffari , Abdolvahab Moradi ,
Volume 10, Issue 1 (1-2016)
Abstract
Abstract
Background and Objective: Agr is the most important regulatory system for the expression of Staphylococcus aureus virulence factors in different conditions. Agr acts as a quorum sensing system in this bacterium which is activated by increased cell concentration during the transition from logarithmic growth phase to stationary phase. Its role is to upregulate the secretory virulence factors such as alpha-hemolysin and inhibit the transcription of surface proteins including protein A-encoding gene. The aim of this study was to assess the relationship between the agr system expression and some virulence factors of Staphylococcus aureus in Brain-heart infusion (BHI) culture medium.
Methods: The expression level of agrA and RNAIII genes from the agr locus along with the expression of hla, spa and mecA genes in BHI broth were assessed in different growth phases using Real time-PCR. Also, gyrB was used as an internal control in this study.
Results: The growth curve of the five tested isolates in BHI broth at 24 hours showed that all the isolates had relatively similar growth patterns. AgrA gene expression in the stationary phase was decreased by 0.89-fold compared with the logarithmic phase. Although the expression of RNAIII gene increased by 3-fold, hla expression decreased by 0.47-fold.
Conclusion: An inactive agr system is observed in the BHI broth medium. BHI broth medium contains high amounts of suitable nutrients for the growth of Staphylococcus aureus, thus the bacteria do not require the activity of the agr system for the regulation of the virulence genes in these conditions.
Leili Shokoohizadeh,
Volume 10, Issue 2 (3-2016)
Abstract
ABSTRACT
Typing of bacteria is an important part of epidemiological studies on nosocomial infections. Bacterial identification methods have dramatically improved in recent years, which is mainly due to advancements in the field of molecular biotechnology. In many cases, molecular techniques have replaced phenotypic typing methods.
Currently, a wide range of bacterial typing techniques is used that are different from one another in the aspects of study objectives, costs, reliability and discriminatory power. None of the typing methods can achieve all desired objectives of a study alone.
Different typing methods are used for various purposes including: 1. confirmation of epidemiological relationships in spread of an infection, 2. providing epidemiological hypotheses about epidemiological relationships between bacteria in the absence of epidemiological data, 3. describing the distribution of bacterial types and identification of affecting factors. Inferences of epidemiological studies depend on the chosen typing technique and objectives of the study.
Therefore, the typing technique can be useful and effective in increasing our understanding of the pathogenesis, transmission and prevention of possible diseases. The aim of this study was to evaluate various methods of molecular typing of bacteria and to compare these methods from different aspects.
Hami Kaboosi , Abolfazl Khandan Del , Ezzat Allah Ghaemi , Sepide Bakhshande Nosrat, Ali Asghar Ayatollahi , Nastaran Golriz ,
Volume 10, Issue 2 (3-2016)
Abstract
ABSTRACT
Background and Objective: Staphylococcus aureus is the most common and important infectious agent. This bacterium can enter the bloodstream and cause some complications in the intensive care unit (ICU).This organism can frequently be found in the nose and transmitted by the carriers. This study aimed to determine the efficiency of eradicating S. aureus from the nose of ICU personnel in reducing the risk of S. aureus infections in the Panje Azar Hospital in Gorgan, Iran.
Methods: Sampling was done using sterile swabs collected from the anterior nasal passages.All samples containing Gram-positive cocci were sent to the laboratory of Faculty of Medicine for identification and evaluation of methicillin resistance. All S. aureus nasal carriers were treated with mupirocin ointment b.d for 5 days. The Samples were cultured again after five weeks to evaluate the eradication of S. auerus from the nose of subjects.
Results: Overall, seven ICU personnel (11.7%) were S. aureus carriers. Two isolates (3.3%) were found as methicillin resistant using both methods of disc diffusion and PCR. The frequency distribution of positive cases indicated a significant difference in terms of work experience (P = 0.012).
Conclusion: The findings show that treatment of carriers with 2% mupirocin topical ointment eradicates S. aureus from the nose. No S. aureus isolates was found in reculture of nasal samples. Treatment of healthy carriers can significantly reduce the risk of infections caused by the bacterium in the ICU.
Pouya Khodadadi , Mehdi Bizhanzadeh , Akram Najafi, Vajiheh Zarinpour, Abdolali Moshfe , Hossein Ansari ,
Volume 10, Issue 4 (7-2016)
Abstract
ABSTRACT
Background and Objective: Antibiotic-resistant Staphylococcus aureus strains have become a problem in treatment of infections caused by S. aureus. This study aimed to evaluate antibiotic resistance in S. aureus isolates from raw milk and detect femA gene in these isolates, as a confirmatory test for identification of S. aureus species.
Methods: This cross-sectional study was performed on 110 raw milk samples. After culture in Cooked Meat broth, presence of S. aureus in grown colonies was confirmed in accordance with Iranian National Standard, No. 1194. Antibiotic resistance was then evaluated according to guidelines recommenced by the Clinical Laboratory Standards Institute. FemA-specific polymerase chain reaction was performed on antibiotic-resistant strains using specific primers and standard strains to differentiate S. aureus from other species.
Results: S. aureus were found in 43 (39.09%) of the 110 collected samples. Among these isolates, 79.07% and 76.75% were phenotypically resistant to penicillin and ceftazidime, respectively. In addition, the femA gene was detected in all isolates.
Conclusion: The results of this study show a high prevalence of resistance to penicillin and ceftazidime among S. aureus strains isolated from raw milk.
Keywords: Staphylococcus aureus, Antibiotic Resistance, PCR.
Azizollah Ebrahimi Kahrizsangi , Saied Habibian Dehkordi , Ziba Shabanpur, Reza Hakimi Alni , Majid Hemati,
Volume 10, Issue 6 (11-2016)
Abstract
ABSTRACT
Background and Objective: Biofilms are community of bacteria that attach to inanimate surfaces or living tissues via production of extracellular polymers and exopolysaccharide matrix. Microbial biofilms on various surfaces of the hospital environment are considered as a reservoir of infection spread. The present study aimed to evaluate the disinfecting effect of benzalkonium chloride on some bacterial isolates causing nosocomial infections.
Methods: First, 13 isolates from four bacteria including Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter and Enterobacter were obtained from Microbiology Laboratory of Al-Zahra Hospital in Isfahan, Iran. The samples were transferred to Microbiology Laboratory of Faculty of Veterinary Medicine of Shahrekord University for testing. Evaluation of biofilm formation and determination of minimum inhibitory concentration (MIC) of the disinfectant and effect of the disinfectant on planktonic growth and biofilm formation were performed.
Results: All bacterial isolates (52 cases) produced biofilm. Mean MIC of benzalkonium chloride for P. aeruginosa, S. aureus, Enterobacter and Acinetobacter was 0.14, 0.2, 0.18, 0.17 g/ml, respectively. Planktonic growth of all four bacteria was inhibited at concentrations of 2MIC, MIC and 1/2MIC. Biofilm was not produced in MIC and 2MIC concentrations, and biofilm formation capability increased by reducing the concentration of benzalkonium chloride.
Conclusion: The results show that the use of appropriate concentration of benzalkonium chloride can prevent the growth of different bacterial species, but sub-MIC dose of this disinfectant may stimulate biofilm formation.
Keywords: Biofilm, Benzalkonium Chloride, Pseudomonas Aeruginosa, Staphylococcus Aureus, Enterobacter, Acinetobacter.
Taiebeh Tamoradi, Hamid Goudarziafshar , Somayeh Rashki , Fatemeh Katouzian, Firoozeh Chalabian,
Volume 11, Issue 2 (3-2017)
Abstract
ABSTRACT
Background and objectives: Synthesis and characterization of several metal complexes (metal ions: Co2+, Ti4+ and Ce3+) of macroacyclic Schiff base ligand have been reported. The Schiff base ligand is prepared from the condensation reaction of 1, 4-di-(4-fluoro-2-aminophenoxy) butane with salicylaldehyde in ethanol. In addition, antibacterial activity of metal ions, Schiff base ligand and their complexes have been investigated. Recent studies show that many Schiff base complexes have antibacterial activity against Gram-positive and Gram-negative bacteria. Therefore, we aimed to synthesize new Schiff base complexes and evaluate their antibacterial activity against a number of Gram-positive and Gram-negative bacteria.
Methods: Schiff base ligand and their complexes were characterized by mass spectrometry and IR, H-NMR and C-NMR spectroscopy. The in vitro antibacterial activity of the Schiff base ligand, metal ions and their complexes were evaluated against some Gram-positive and Gram-negative bacteria by disk diffusion method and determining minimum inhibitory concentration.
Results: In this study, the Schiff base complexes had good antibacterial activity, but the Schiff base ligand and metal ions did not show any antibacterial effect. In some cases, the antibacterial effect of the complexes was higher than that of the standard antibiotics tetracycline and gentamycin. The titanium complex showed the highest antibacterial activity in both methods. This complex created the largest growth inhibition zone (diameter: 100mm) against Staphylococcus aureus, and had the lowest minimum inhibitory concentration against Bacillus subtilis (6.75 mg/ml).
Conclusion: The compounds synthesized in our study have strong antibacterial activity.
Keywords: Schiff base complex, Schiff base ligand, antibacterial activity, Staphylococcus aureus, Bacillus subtilis.
