Showing 27 results for Antibiotic
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
Tajeddin, E. (msc), Jahani Sherafat, S. (msc), Seyyed Majidi, M. R. (md), Alebouyeh, M. (phd), Nazemalhosseini Mojarad, E. (msc), Pourhossengholi, A. (phd), Mohammad Alizadeh A H (md), Zali, Mr (md),
Volume 5, Issue 2 (10-2011)
Abstract
Abstract Background and objectives: Bile in healthy people is a sterile fluid and presence of any microorganism can be a marker for a disorder like cholelithiasis. The aim of this study was to determine the frequency of bacterial agents in the bile of patients with bilestone, malignant pancreatic and biliary diseases. Material and Methods: One hundred and two bile samples were obtained, during six months in 2011, from patients subjected to ERCP in Taleghani hospital, Tehran. First, Patient's clinical data, the type stone, and their disease status were studied, and then the microbiological investigations, such as culture, identification of the bacteria and detection of their counts, drug susceptibility testing and molecular tests (16s rDNA PCR) performed on all the samples. Higher than 103 bacteria counts for each sample, in the absence of underlying infections, was considered as stable colonization. We run SPSS version 13 to analyze the data. Results: Out of 42(41.1%) positive bile culture samples, 59 bacterial isolates are detected by conventional methods. Of culture negative samples, seven have bacterial DNA indicated by PCR method. The most isolated bacteria are E. coli (%34.4), Enterococcus spp. (%19.7), Klebsiella pneumoniae (%18) and Pseudomonas aeruginos (18%). The most frequent stones are cholesterol, black pigment and brown pigment, respectively. There is no significant association between the diseases, stones and types of bacteria. Previous antibiotic usage (44.6%) is meaningfully more than that of other biliary problems (p=0.01) Conclusion: The presence of bacteria, Escherchi coli and Entrococcus which are the most in bile samples, is considered as a risk factor in pathogenesis of biliary disorders. Further studies on the pathogenesis and pathophysiological effects of bacteria can help us to clarify the role of bacteria in producing bile stones. Key words: Bile stones, Bacteria, ERCP, Antibiotics.
R Esmaeili, R Yousefi Mashouf, A Moshtaghi, M Alikhani,
Volume 7, Issue 5 (2-2014)
Abstract
Abstract
Background and Objective: Bacterial infectioins in particular meningitis, pneumonia and septicemia are still some of the most causes of mortalities in children.The aim of present study was to identify the most common bacterial agents causing infectionis in children under 14 and detection of antibiotic resistance paterns.
Material and Methods: During two years,1897samples were obtained from the patients suspected bacterial infectioins. They were investigated for bacterial cultures, age, sex and antibiogram patterns. The species were identified by biochemical and serological methods.
Results: Of 1897 samples, 563 (29.6%) had positve bacterial culture. Of these 74.7% were gram negative and 25.3% gram positive . The most common species were Escherichia coli(34.1%), Staphylococcus aureus (17.1%), Psuedomonas aeroginosa (12.4%), Kelebsiella (11%) and Staphylococcus epidermidis (5.7%). The most effective antibiotics against both gram positive and gram negative bacteria were ceftriaoxne, nitrofurantoin, nalidixic acid, amikacin and gentamycin.
Conclusion: The gram negative bacteria in particular Escherichia coli, Psuedomonas aeroginosa and Kelebsiella are the predominant causes of bacterial infections in children under 14 in these regions. Most species showed a high relative resisitance to routine antibiotics such as ampicillin, trimethoprim and chloramphenicol.
Key Words: Bacteria Infection Children Antibiotic
R Golsha, V Kazeminejad, A Barzegari, S Besharat, F Ghasemi Kebria,
Volume 7, Issue 5 (2-2014)
Abstract
Abstract
Background and Objective: The excessive use of broad-spectrum antibiotics will lead to drug resistance of microorganism and specially nosocomial organisms. Because of high incidence of antibiotic resistance in hospitals, we aimed to study antibiotic resistance to gram negative bacteria.
Material and Methods: This cross-sectional study was conducted on the data of biological samples (2006-2008), with positive culture result. Using antibiogram, microbial resistance to isolated microorganism was determined, and after culturing the samples, bacteria were identified by using differential media and antiserum. Then, antibiotic resistance was performed by disk diffusion.
Results: The most common gram-negative microorganism obtained from all cultures was Ecoli with the lowest drug resistance to Nitrofurantoin.
Conclusion: Based on the results, antimicrobial resistance pattern is not the same in different places and furthermore it is ever changing. Therefore, further research is needed to be done to have an accurate pattern of antibiotic resistance to provide effective treatment regimens.
Key words: Antibiotic Resistance Disk Diffusion Gram Negative Bacteria Gorgan
F Habibi Nava, M Hashemi Karouei, Sh Shafahi,
Volume 7, Issue 5 (2-2014)
Abstract
Abstract
Background and Objective: Resistance of Helicobacter Pylori (H. pylori) to antibiotics is the main cause of relapse into Helcobacterial infections. With the use of several antibiotics that have synergistic effect, we can inhibit this antibiotic resistance. Thus, we aimed at determining resistance patterns and assessing the synergy of combining multiple antibiotics on H. pylori.
Material and Methods: Biopsy specimens were taken from 100 patients with gastric ulcer referred to Imam Reza hospital in Amol, north of Iran. After isolation and identification of H. Pylori, antibiogram was performed with different antibiotic disks containing one antibiotic, a combination of two antibiotics (metronidazole + clarithromycin) and three antibiotics (metronidazole + Claritromycin + Ciprofloxacin).
Results: In this study, H. pylori were isolated from 53 (53%) biopsy specimens. Of these, 49 (5.92%) were resistant to metronidazole, 14 (26%) to amoxicillin, 10 (19%) to clarithromycin, 7 (13%) to tetracycline, 13 (5/24%) to furazolidone and 7 (13%) to ciprofloxacin. In survey of synergistic effect, an increase in inhibition zone diameter around of combined disks was seen up to 5mm compared to the most effective antibiotic.
Conclusion: The inhibition zone diameter of discs containing two and three antibiotics was large, in comparison with one antibiotic.
Key words: H. Pylori Antibiotic Resistance Synergy Effect
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
Kargar, M, Ebrahimi, E, Amini, J, Najafi, A, Kheirkhah, B,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract
Background and Objective: Listeria monocytogenes is a bacterium transferred by foods and is the agent of many sporadic and epidemic diseases in humans. This study aimed to investigate the prevalence of L. monocytogenes and to determinine their antibiotic resistance profile in red meats.
Material and Methods: this cross-sectional study was performed on 400 red meat samples obtained from industrial slaughterhouses placed in Kerman, Iran. First, the samples were enriched with Simultaneous Enrichment Broth (SEB), and then plated onto Palcam agar and Tryptic Soy Broth Yeast Extract Broth (TSAYE). After identification of the isolates based on biochemical tests and PCR, the isolates were checked for their antibiotic resistance profile using disk Diffusion
Results: of 400 samples, 12 samples (3%) were contaminated with different species of Listeria. Using PCR, hly gene was recognized in eight samples (2%) of L. monocytogenes. Furthermore, there was a significant difference in isolation rate of lamb samples compared to cow ones. While all of the isolates were resistant to clindamycin, amikacin and chloramphenicol, they were sensitive to penicillin.
Conclusion: in spite of low rate of infection in red meat samples in Kerman city, due to high risk of Listeria contamination in red meats, we recommend applying a routine screening to identify this bacterium in our county.
Keywords: Listeria Monocytogenes, Hly Gene, Red Meat, Antibiotic, Kerman
Shokoohi Zade, L, Mohabbati Mobarez, A, Alebooye, M, Ranjbar, R, Zali, Mr,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Background and Objective: some of predisposing factors for enterococci colonization are hospitalization in ICU, prolonged use of antibiotics and continued bed rest in hospital. In this study antibiotic resistance of enterococcus in hospitalized patients of four hospitals in Tehran were studied. Material and Methods: the Clinical samples were taken from patients admitted to the ICU, from September 2011 to April 2012. Enterococci isolates were confirmed by biochemical tests, and Enterococcus faecalis and Enterococcus species by species-specific ddl genes. The disk diffusion and micro agar dilution susceptibility tests were performed according to Clinical and Laboratory Standards Institute (CLSI). Results: of 41 isolates in ICUs, 22 (5.52%) were E. faecium and 19 (5.47%) were E. faecalis. Most of E. faecium was isolated from urine and E. faecalis from trachea specimens. The rate of resistance to vancomycin, ampicillin, gentamicin, chloramphenicol and nitrofurantoin in E. faecium isolates was more than that of E. faecalis and the rate of resistance to tetracycline, ciprofloxacin and erythromycin was the same in both of them. MIC50 in vancomycin and ampicillin resistant E. faecium isolates was greater than 256 microgram and the MIC50 in gentamicin resistant isolates was more than 1024 microgram. . Conclusion: The presence of multi-resistant E. faecium strains in ICUs can be a serious warning for physicians and patients. Key words: Enterococcus faecium, Enterococcus faecalis, ICU, Antibiotic Resistance
Asghari Estiar, M, Rafi, A, Heidarzadeh, S, Ohadian Moghadam, S, Mahboubi, R, Monadi Sefidan, A, Allafzadeh, J, Nik Khah, H,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Background and Objective: One of the main causes of increased mortality in cancer patients is bacteremia. On the other hand, antibiotic resistance is the major cause of treatment failure in malignant diseases especially in hematological malignancies. The aim of this study was to diagnose the bacterial strains isolated from blood specimens of cancer patients and to determine their antibiotic susceptibility. Material and Methods: In this cross-sectional study, 0.5 ml of venous blood was taken from 613 cancer patients especially leukemia, and blood cultures and antibiotic susceptibility tests were performed using standard methods. Using disc diffusion method, antibiotic susceptibility was performed with a wide range of antibiotics. Results: Out of 613 cultured specimens, 153 (25%) were found to be positive including 76.47% of gram negative and 23.53% of gram positive bacteria. The most common isolated bacteria were E. coli, coagulase-negative Staphylococci, Klebsiella, Staphylococcus aureus and Pseudomonas aeroginosa, respectively. Conclusion: It seems that Ceftriaxone is the best choice for the treatment of gram negative caused bacteremia and Gentamicin for bacteremia caused by gram positive agents. Given the high level of resistance to the commonly used antibiotics, it seems reasonable to avoid of early and inappropriate use of antibiotics to prevent the development of drug resistant bacteria. Keywords: Cancer, Blood Cultures, Bacteremia, Antibiotic Resistance
Ebrahimipour, Gh., Moradi, A, Karkhane, M, Marzban, Ar,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Bachground and Objective: most of environmental microorganisms have the genes resistance to antibiotics and metals. The aim of the current study was to survey resistance pattern to some antibiotics and heavy metals in three pseudomonas aeruginosa isolated from different ecological areas. Material and Methods: first, the isolates were identified by biochemical methods and phylogenetic analysis. Then, the evaluation of antibiotic resistance was conducted by disc diffusion and that of Heavy metal resistant by agar dilution, in a range of 50-500 µg/ml. Results: The results showed that all three isolates were resistant to beta lactam antibiotics. Although these isolates were highly resistant to heavy metals, no relationship was observed between ecological sources and the resistance pattern in ICT1 and Abt2 strains. However, strain Q isolated from digestive system of ParmacellaIberica showed high resistance to antibiotics and low resistance to heavy metals. Conclusion: given that environmental bacteria have a high potentiality for carrying resistance genes and this can be an advantage environmentally, they could be used to remove heavy metals from polluted areas. On the other hand, resistance genes medically are a concern due to probability of transferring to pathogen strains. Keywords: Antibiotic Resistance, Heavy Metal Resistance, Pseudomonas Aeruginosa
Naghipoor, E, Raefi, A, Nasrollahiomran, A,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Background and Objective: Enterococci are normal flora of human body and considered as the third leading cause of nosocomial infections. The aim of this study was to determine drug resistance of Enterococcus species through biochemical methods. Material and Methods: One hundred twenty-eight of enterococcus suspected samples were isolated from gorgan and gonbad’s hospitals from April to June, 2013. The samples were cultured on blood agar, chrome-agar, EMB agar and some special cultures of isolation of Enterococcus species. Suspension of bacteria was grown in Mueller Hinton agar and the inhibition zone diameter was determined by disk antibiogram. Results: Of 128 samples, 109(85.15%) were enterococci faecalis and 19 (14.85%) Enterococcus Faecium. In all of 128 cases, eight showed resistance to amoxicillin, ten to ampicillin, five to gentamicin, five to ciprofloxacin, six to chloramphenicol, four to cephalexin and one to vancomycin. Conclusion: It seems to be necessary to use drug sensitivity test for having appropriate treatment and preventing from resistance strains. Keywords: Enterococci, Antibiotic Resistance, Antibiogram
Shahraki, Sh, Bokaeian, M, Rigi, Sh,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Background and Objective: Klebsiella pneumoniae is an opportunistic nosocomial pathogen causing a variety of infections including urinary tract infections, pneumonia, septicemia, wound infections and infections in the intensive care units. Since the ESBL producing Klebsiella pneumoniae strains are increasingly causing urinary tract infections, we aim to assess antibiotic resistance pattern and evaluate the prevalence of ESBL in Klebsiella pneumoniae isolated from urinary tract infections. Material and Methods: this cross-sectional study was conducted on 122 Klebsiella pneumoniae strains collected from Zahedan hospitals. After final identification of isolates, antibiotic susceptibility tests were carried out by using disk diffusion in agar method for 16 antibiotics and ESBL production was determined by the combined disk method. Results: The Klebsiella pneumoniae strains showed susceptibility to imipenem and amikacin ( 94.3%) ,chloramphenicol (88.5%) , gentamicin (81.1%) , ciprofloxacin (80.3%) , cefepime (73%) ,streptomycin (72.1%), nalidixic acid (68%) , tetracycline (65.6%), and cefotaxime, ceftazidime, cefpodoxime (62.3%) . The resistance of strains was seen to nitrofurantoin (53.3%), cotrimoxazole (39.3%), Cefpodoxime (37.7%), cefotaxime (36.9%), ceftriaxone (36.1%), aztreonam (34.4%), ceftazidime (32.8%). Thirty-eight isolates (31.1%) were shown to produce ESBLs. Conclusion: A high rate of resistance was observed to most of the antibiotics among ESBL producing strains therefore, it is important to be careful about the use of antibiotics and identification of ESBL using phenotypic methods. Keywords: Antibiotic Resistance, Extended Spectrum Beta-Lactamases,KlebsiellaPneumoniae, Urinary Tract Infection, Isolate
Monadi, M, Kargar, M, Naghiha, A, Najafi, A, Mohammadi, R,
Volume 9, Issue 1 (4-2015)
Abstract
Abstract
Background and Objective: Salmonellosis is the most common type of food poisoning in developed and developing countries that is caused by Salmonella serotype. Hence, we aimed to identify the Salmonella serovars in eggs obtained from Kohgiluyeh and Boyerahmad province and to evaluate antibiotic resistance of the isolated strains.
Material and Methods: In this study, 210 eggs were collected from Kohgiluyeh and Boyerahmad Province. The bacteria were isolated and identified using biochemical tests. After extraction of genomic DNA, Salmonella gender, Salmonella enteritidis and Salmonella typhimurium were investigated by invA, fliC and sefA primers, respectively, using Multiplex PCR method.
Results: Of 210, 14 (6.66%) were contaminated with Salmonella. Of these, 12 (5.71%) were Salmonella typhimurium and 2 (0.95%) were related to Salmonella spp. None of the samples were contaminated with Salmonella enteritidis. The highest resistance was related to penicillin (100%) and neomycin (78.57%).
Conclusion: Salmonella typhimurium is the predominant serovar causing contamination in the eggs of this Province. Given the wide spread of antibiotic resistance in different serotypes of Salmonella, we recommend avoiding of indiscriminate use of antibiotics in livestock and poultry.
Keywords: Salmonella, Drug Resistance, Antibiotic, Multiplex PCR, Kohgiluyeh and Boyerahmad
Zamani, M, Mazinani, Z, Sardari, S,
Volume 9, Issue 2 (7-2015)
Abstract
Background and Objective: Antibiotics are the chemical compounds, which are produced by microorganisms, belong to a larger group of antimicrobial compounds that are used for treatment of infections caused by microorganisms.
Material and Methods: the isolates of four plant species, Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium and Hippocrepis unisiliqousa were obtained using Trypticase Soy Agar. First, the purified isolates were screened from the viewpoint of their ability in producing antimicrobial metabolites against three typical microorganisms Escherichia coli, Candida albicans and Saccharomyces cerevisiae. Then, the microbial products were extracted using organic solvent ethyl acetate and their minimum suppression concentration was determined against three strains Candida albicans ATCC 10231، Staphylococcus aureus ATCC 25923 و Escherichia coli ATCC 25922.
Results: After 4-7 days of incubation, 104 bacterial samples were isolated from isolates four plants. Out of this number, 26 isolates were antimicrobial producing metabolites by making inhibition zones against three typical microorganisms, after initial screening for production of antimicrobial compounds using agar diffusion method. Minimum inhibitory concentration of ethyl acetate extracts from target microbes were between 125-1000 µg/ml.
Conclusion: The results showed that the bacterial extracts of phylosphere produce some compounds with antimicrobial properties.
Keywords: Antibiotic Producing Bacteria, Fabaceae, Asteraceae
Naghdi, N, Ghane, M,
Volume 9, Issue 3 (9-2015)
Abstract
Background and Objective: Propionibacterium acne is one of the main causes of acne. Due to the spread of drug resistance, it is not responsive to treatment. This study aimed to determine antibiotic sensitivity of strains of the Propionibacterium acne.
Material and Methods: seventy samples of acne lesions were collected to study the presence of Propionibacterium acne. Microbial Culture technique was used to detect and identify Propionibacterium acne. Antibiotic resistance of the isolates to the antibiotics of Doxycyclin, Azithromycin, Erythromycin, Tetracycline, Clindamycin and Trimethoprim sulfamethoxazole was studied by Antibiogram method.
Results: Of 70 samples, 14 (20%) were positive for Propionibacterium acne. The results of phenotypic test were confirmed using molecular method. Rate of resistance to Azithromycin and Erythromycin (50%), Clindamycin (35.71%), Trimethoprim sulfamethoxazole (28.57%), Doxycycline and Tetracycline (14.29%) was determined.
Conclusion: Outbreak of antibiotic resistance to Azithromycin, Erythromycin, and Clindamycin is high. Since the Propionibacterium acne is sensitive to Doxycycline and Trimethoprim Sulfamethoxazole, it is recommended using them to treat acne.
Keywords: Antibiotic susceptibility, Propionibacterium Acne, Ance Protein.
Mm Soltan Dallal, Z Rajabi,
Volume 9, Issue 3 (9-2015)
Abstract
Abstract
Background and Objective: This study aimed to investigate the antimicrobial susceptibility of the most common pathogens in hospitalized neonates in Intensive Care Unit.
Material and Methods: In this one-year descriptive study, 150 blood samples of neonates in Intensive Care Unit of Bahrami hospital of Tehran were divided into two groups of early onset sepsis (the first 72 hours of life) and late onset sepsis (after the 72 hours of life). After isolating and identifying of bacteria, their antibiotics susceptibility was studied by Kirby- bauer method in accordance with CLSI guidelines.
Result: The most isolated organisms were Klebsiella pneumoniae (41.3%). Coagulase negative staphylococcus was the cause of early onset septicemia and Klebsiella pneumoniae of both early and late onset septicemia. The highest susceptibility in gram-negative microorganisms was shown to Ciprofloxacin (89.6%) and in gram positive to Vancomycin (82.8%).
Conclusion: Gram-negative bacteria are the main cause of contamination in NICU and ciprofloxacin is the most effective antibiotic. Thus, it is imperative that NICU should be extremely controlled.
Keywords: Septicemia; Antibiotic Susceptibility; Neonatal Intensive Care Unit
Shafiee, F, Khosravi, Ad, Azarpira, S, Babaie Barkalaie, A, Abbasi Montazeri, E,
Volume 9, Issue 3 (9-2015)
Abstract
Background and Objectives: Pseudomonas aeruginosa is the most common organism, which is separated from the burn infections. Due to increased antibiotic resistance, there are many problems to deal with the infections caused by Pseudomonas aeruginosa. This study aimed to determine the resistance to antibiotics against clinical isolates of Pseudomonas using phenotype methods.
Material and Methods: 100 strains of Pseudomonas aeruginosa were collected from the burn patients in Taleghani hospital in Ahwaz, Iran, during a six-month period. After phenotypically initial identification, antibiotic sensitivity of isolated strains to conventional antibiotics against Pseudomonas aeruginosa was determined using a disk diffusion technique, and Phenotypic screening for MBLs production was performed.
Results: the maximum percentage was related to wound infection and the frequencies of the resistance to imipenem, meropenem, piperacillin, piperacillin-tazobactam, ceftazidime, gentamicin, amikacin, and ciprofloxacin, doripenem, ertapenem and colistin sulphate, were 70%, 53%, 83%, 67%, 91%, 88%, 84%, 84%, 33%, 90%, and 0%, respectively. The use of CD Test methods was approved for determining resistance to Carbapenems.
Conclusion: antibiotic resistance to Pseudomonas aeruginosa is increasing and colistin sulphate is the most effective antibiotic.
Keywords: Pseudomonas Aeruginosa; Burn Infection; Antibiotic Resistance.
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.
Majid Komijani , Majid Bouzari , Fateh Rahimi ,
Volume 11, Issue 2 (3-2017)
Abstract
ABSTRACT
Background and Objective: Escherichia coli is one of the most common causes of hospital-acquired infections. Extended-spectrum β-lactamase (ESBL)-producing E. coli strains are resistant to third-generation cephalosporins. The three main genes involved in ESBL production are TEM, SHV and CTX-M. Detection of ESBL-producing E. coli is of importance for infection control, reduction of excessive antibiotic use and epidemiological surveillance. This study aimed to detect ESBL-producing E. coli strains isolated from wound infections using phenotypic and molecular methods.
Methods: During 2013- early 2015, 86 strains were collected from three hospitals in Isfahan, Iran. Antibiotic susceptibility testing was done using ceftazidime and ceftazidime + clavulanic acid discs. Polymerase chain reaction was used for the detection of the three resistance genes.
Results: The resistance genes SHV, CTX-M and TEM were detected in 49 isolates (56.9%). In addition, 39 isolates (45%) were ESBL-producing strains. According to the results, 5 (5.8%), 14 (16.2%), 19 (22%) and 11 (12.7%) isolates contained the SHV, CTX-M, TEM and CTX-M + TEM genes, respectively. The frequency of CTX and TEM were significantly higher than that of SHV gene (P <0.05). Most of the isolated bacteria were resistant to cefazolin and sensitive to nitrofurantoin.
Conclusions: There is a difference between the frequency of ESBL-positive isolates reported in the phenotypic and genotypic methods, which could be due to the lower sensitivity of the phenotypic method and impact of environmental factors on the emergence of antibiotic resistance.
Keywords: Antibiotic resistance genes, ESBL, TEM, SHV, CTX-M, Escherichia coli.
Shahram Shahraki Zahedani , Nasrin Sayadzai,
Volume 12, Issue 2 (3-2018)
Abstract
ABSTRACT
Background and Objectives: Diarrheagenic Escherichia coli (DEC) pathotypes are important causes of diarrhea among children in developing countries. The objective of this study was to determine the frequency and antibiotic resistance pattern of DEC pathotypes in children aged less than 10 years.
Methods: This cross-sectional study was done on 300 E. coli strains isolated from diarrheic stool samples of children aged less than 10 years who were admitted to hospitals and central laboratory in Zahedan, between July and October 2016. DEC pathotypes were identified by standard biochemical testing and phenotypic testing using polyvalent antiserums. Antibiotic resistant pattern of these strains was evaluated against 11 different antibiotics by the agar disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines.
Results: Of the 300 E. coli isolates, 89 (29.6%) were found positive for DEC using polyvalent antiserums. In this study, 35 cases (39.3%) reacted with antiserum 1, 21 cases (25.8%) reacted with the antiserum 2, and 31 cases (34.8%) reacted with antiserum 3. The highest rate of resistance was observed against ampicillin (94.8%), tetracycline (87.2%), and co-trimoxazole (70.5%). In addition, the lowest rate of resistance was related to imipenem (1%) and ciprofloxacin (8.9%).
Conclusion: DEC pathotypes are the important causes of diarrhea among children admitted to hospitals of Zahedan. Considering the high rate of antibiotic resistance among these pathotypes in this region, prescription of antibiotics should be based on accurate detection of these strains.
Keywords: Escherichia coli, Child, Antibiotic Resistance.
