Showing 16 results for Antibiotic Resistance
R Nosoohian, M Yavari, A Ajami, M Sadegh,
Volume 1, Issue 1 (4-2007)
Abstract
Abstract Background and objectives :Epidemic dysentery, which can be caused by different organisms, is a major problem in developing countries. The cause variability and drug resistance make the treatment difficult. This study was carried out to determine the prevalence and antimicrobial susceptibility patterns of Shigella in Isfahan reference laboratory. Materials and Methods: In this descriptive study,200 stool samples referred to Isfahan Reference Laboratory were examined to detect possible microorganisms and their antibiotic sensitivity. Results:The Shigella and Salmonella infections rates were 17% and 0.5%. Shigella which is the most frequent cultured organism(97% of bacterial samples) includes: 79% Sd1, 15% Shigella Flexneri and 5% Shigella Sunnei. None of the samples was infected by Ecoli O157H7 or Entamoeba histolitica. The most effective ntibioticwas Ciprofloxacin (no resistance was seen to this antibiotic). Conclusion: The most important cause of bacterial dysentery in this study was shigellosis (sd1). Antibiotic resistance to ampicillin, Amoxiclav and Cotrimoxasole was quite high. This necessitates avoiding to empirical treatment of dysentery. Keywords: Dysentery, Antibiotic resistance, Salmonella, Shigella, Ecoli
F Niknezhad, Mj Kabir, A Keshtkar, B Hazrati, N Kurdjazi, I Rezayyan, Ah Ankizeh,
Volume 1, Issue 2 (10-2007)
Abstract
Abstract Background and objectives: Vibrio Cholera is one of the causative agents that can easily lead to death if the appropriate therapeutic measures are not taken in time. The purpose of this study is to identify the antibiotic sensitivity of the isolated V. choleras from the patients during the outbreak of Cholera in Golestan province, 2005. Materials and Methods: The Subjects were 97 positive cultured samples sent by different laboratories of Golestan province health centers .First, these samples were confirmed with microbiological and biochemical tests. Then, their antibiotic sensitivity was examined by Kirby –Bauer method (12 routine drugs were used).To obtain better results, the tests carried out in parallel by two expert technologists. Results: The participants, aged 29.8 +- 16 years, are male (52.6%) and female (47.1%). The highest antibiotic susceptibility pattern is related to Cephotaxime (91.6%), Ceftizoxime (87.8%), Oxcy Tetracycline (76.1%) while the most antibiotic resistance is referred to Nalidixic Acid (84.5%), Fourazolidin (50.7%) and Erythromycin (50.7%). During outbreak, Antibiotic resistance was not increased. Both technologists reports regarding Ampicillin, Tetracycline, Nalidixic Acid (kappa of 94%, 89%, 82%, p value<0.05) have the most agreement while it is not true about Erythromycin and Fourazolidin disks. (Kappa 67% and 62%, p value<0.05) Conclusion: Because of the resistance of Vibrio cholera to different antibiotic agent, it is important to determine their pattern to control and prevent the spread of drug resistance species. Key words: Vibrio cholera, Inaba, antibiotic resistance, Golestan
F Sedighian, A Sanee, H Alaouddoulee, M Arshi, Kh Rekabpoor,
Volume 2, Issue 2 (10-2008)
Abstract
Abstract Background and objectives: Resistance to antimicrobial agent is a world-wide problem and the existed reports are not the same. Aware of antibiotic resistant pattern of microorganisms in each hospital is important for controlling the nosocomial infections. This study was designed to determine the resistant pattern of microorganisms isolated in Yahya nejad hospital, Babol, north of Iran. Material and Methods: In this descriptive study, organisms were isolated during 2006 from urine, blood, endotracheal tube, abscess, fluids (ascites, pleura, and synovia), wound, discharges and bonemarrow of both outpatients and inpatients in our hospital were studied. Their antibiotics resistances were evaluated by Kirby Bauer method. Results: of 3114 culture specimens of admitted patients (female 1732, male 1382), 325 (10.4%) microorganisms were isolated. They were isolated from urine 162(49.8%), blood 115(35.4%), abscess 11(3.4%), wound, 10(3.1%) and discharge10 (3.1%). The most common microorganisms were Escherichia coli 107(33%) and Staphylococcus epidermidis 69(21.3%). Maximum resistance of E.coli is related to tetracycline (83.9%) and ampicillin (75%) and maximum resistance of S.epidermidis to oxacillin (89.2%) and penicillin (82.1%). Conclusion: With regard to high antibiotic resistance (>70%) in this study, it seems that the early beginning and inappropriate dosage of antimicrobial agents may be associated with developing antibiotic resistance. Hence, it is highly recommended to prohibit the unnecessary prescription of antibiotics Key words: Antibiotic resistance, microorganisms, Blood culture, E.coli
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
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
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
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.
