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Background and purpose : -Helicobacter pylori is a gram negative spiral bacilus which infects gastric mucosa and causes a wide range of gastro intestinal diseases.Unfortunately the prevalence of the infection by this organism in developing countries is high and despite numerous existing drug regimens, treatment fails to eradicate the organism in many occasions. To reach an effective and curative regimen, invitro determination of suscepibility and resistance of the organism, to various antimicrobials, is pradent. The goal of this study was to determine the prevalence of antimicrobial resistance in Helicobacter pylori,s isolated from cultures. Biopsies from 67 patients admitted to the Sari Imam Hospital were used to cultur Helicobacter pylori and determine their susceptibility and resistance to metronidazole, claritromycin and amoxycillin.
Materials and methods : Disc diffusion tecniqu was used to determine the minimum inhibitory concentration , (MIC) and resistance pattern of the isolated Helicobacter pylori.In this method we used the cutoff point of MIC 90 ie , a concentration at which 90% or more of culture plates show inhibition zone around the antimicrobial test disc.
Results : MIC 90 for amoxycillin and claritramycin in our study was 0.25 g/ml and all isolates were susceptible to amoxycillin. Only one isolate was resistant to claritramycin. MIC 90 for metronidzole was 16 and 4 resistant cases were isolated.
Conclusion : This stndy showed low level of resistance to metronidazole and claritramycin which were comparable to the reported results from other studies. No resistance was observed to amoxycillin which was also the same as other reported results. According to the pattern of antimicrobial resistance, we can recommend the studied drugs, against Helicobacter pylori.

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Background and Purpose: Due to an increase in cases of irrational drug prescription and it's health and economic consequences, evaluation of the rational use of drugs seemed necessary. Among drug groups antibiotics are greatly significant.
Materials and Methods: Utilization pattern of antibiotics in different wards of Sari Imam Khomeini teaching hospital in the first half of 2000 and 2005 were reviewed. ATC/DDD (Anatomic, Therapeutic, Chemical/ Defined Daily Dose) methodology was used.
 Results: Data showed, use of antibiotics jumped from 95.4 DBDs (DDD per patient’s bed-days) to 124 DBDs. Distribution of different class of anti-microbial, showed the highest increase in use of vancomycin and clindamycin. Use of cotrimoxazole and aminoglycosides remained fairly unchanged, howerrs consumption of Penicillin G dropped. In year 2005, ICU ward followed by gynecology, were among the University Hospital departments with the highest consumption of antibiotics. Cefazolin was the most prescribed antibiotics during this study.
Conclusion: It appers that there is a need for more national drug policities and drug education program for health care professionals. Evaluation of drug distribution in hospitals seems to be necessary.

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Background and purpose: Helicobacter pylori, which infect approximately one half of the world’s population, are an important risk factor in chronic gastritis, peptic ulcer disease, and gastric cancer. H. pylori eradication is now widely recommended as the most effective treatment of peptic ulcer disease. One of the most important reasons for treatment failure is H. pylori resistance to the antimicrobials usage in therapy. The aim of this study was to determine susceptibility patterns of H. pylori isolates in 6 routine anti-microbial agents in Northern Iran.
Materials and methods: 125 patients from Tooba Medical Center in Sari with endoscopic evidence of dyspepsia complaints were used for obtaining gastric biopsies specimens. Biopsies were sent to the laboratory in thioglycolate broth (transport medium). Bacteria were primarily cultured on Columbia agar supplemented with 7% horse blood, 7% fetal calf serum. Urease, Catalase and Oxidase activities were used for H. pylori identification. Bacterial suspensions equivalent to 3 Mc. Farlands were spread on plates, along with antibiotic disks and placed in the diameter zone. Inhibition was measured after 3 days of incubation in micro-aerophilic condition.
Results: H. pylori were isolated from 116(92.8%) subjects, a total of 125 biopsy specimens. Resistance to metronidazole, amoxicillin, clarithromycin, tetracycline, furazolidone and ciprofloxacin were 71%, 35%, 25%, 9%, 24% and 25%, respectively. Multiple resistance (amoxicillin-clarithromycin-metronidazole) were found in (6)5% of the isolates.
Conclusion: Comparison of our data with previous results showed that prevalence of H. pylori resistance to clarithromycin, furazolidone and metronidazole has increased in Iran considerably. Resistance to amoxicillin in our study was too high in comparison with foreign studies. The present study demonstrates the need for continuous monitoring of the antimicrobial susceptibility in H. pylori in order to determine the optimal drug regimens.

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Background and purpose: Hospital infections are common throughout the world. Antibiotic resistance is caused after infectious diseases and hospital infections. Considering the importance of hospital infection and bacteria resistant to antibiotics, this study aimed at investigating the prevalence of β-lactamase enzymes in bacteria isolated from nosocomial infections. Material and Methods: Fifty samples of skin infections and 50 samples from wounds were collected from Imam Khomeini Hospital in Sari and were studied using biochemical tests and identification of beta-lactamase. Results: In this study, 180 organisms were isolated from 100 samples of skin infections and wound. The production of β-lactamase enzymes by acidimetric method in these samples showed that 26 samples (14.4%) were β-lactamase positive and 154 samples (85.6%) were β-lactamase negative and gram positive cocci and bacilli. Conclusion: β-lactamase positive bacteria not only increase the risk of nosocomial infections, especially skin infections in people with weakened immune systems but also make them resistant to β- lactam group of antibiotics.

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Background and purpose: Surgical site infection (SSI) is the third leading cause of hospital infections which results in increased morbidity, mortality and costs after cardiac surgery. The importance of prophylactic antibiotics in cardiac surgery has been proved. The aim of this randomized clinical trial was to compare two prophylactic antibiotic regimens (cefazolin and cefazolin plus gentamicin) on surgical site infection in CABG patients in Mazandaran Heart Center. Materials and methods: A total of 400 patients, meeting eligibility criteria, were randomly allocated into two groups. In the control group the prophylactic regimen consisted of cefazolin 2 g IV prior to sternal incision followed by 1 g IV every 6 hours for 72 hours. The intervention group recieved cefazolin 2 g IV plus gentamicin 1.5mg/kg IV before sternal incision followed by cefazolin 1 g IV every 6 hours plus gentamicin 1.5mg/kg IV every 8 hours for 72hrs after the sternal incision. Three, seven, 21 and 30 days after cardiac surgery the patients were observed by a cardiac surgeon for symptoms of surgical wound infection. Moreover, the serum level of creatinine and BUN were measured before the surgery and also in second and forth days after the surgery. Results: From the total of 400 patients 392 were assessed of whom 198 were in control group and 194 were in the intervention group. There was no significant difference between the two groups regarding demographic and clinical variables and also the rate of infection (P>0.05). However, the serum level of creatinine and BUN were significantly higher in intervention group (P<0.05). Conclusion: Since there was no significant difference in infection rates between the two groups and significant increase in serum level of creatinine and BUN in intervention group, using cefazolin as the sole prophylactic antibiotic is suggested to prevent surgical site infection in CABG patients. (Clinical Trials Registry Number: IRCT201201114365N10)

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Background and purpose: Surgical site infections are infections of the tissues,organs,or spaces exposed by surgeons during performance of an invasive procedure,and the development of SSIs is related to the degree of microbial contamination of wound during surgery,duration of the procedure,and host factors.Inguinal hernioplasty is one of the most common surgical operations. The use of prophylactic antibiotic in Lichtenstein hernioplasty is controversial. Hence this study done to evaluate the prophylactic antibiotic effect in reducing the post operative wound infection in Lichtenstein hernioplasty. Materials and methods: This is an interventional double-blind randomized trial on 282 patients under going, Unilateral primary elective inguinal hernioplasty with Lichtenstein method. Using polypropylene mesh. They were randomized to receive 1gr/1v cephalotin (keflin) or equal volume of placebo 30min before incision. Patients were evaluated 1week, 2weeks and 12weeks after surgery by an independent surgeon or resident. Wound infection was defined according to the criteria of centers for Disease control and recorded. Results were assessed using chi-square and t-test as appropriate. Results: We included 282 patients in this study between March 2010 and october 2011. The total number of wound infection was 13 (4.7%), 4(2.8%) in antibiotic group and 9(6.4%) in placebo group (p= 0.29). There was 1 deep infection only in placebo group. Statistical analysis showed no significant difference in two groups. Conclusion: The results show that, in Lichtenstein hernioplasty, routine use of prophylactic antibiotic is not indicated, as it does not significantly reduce the post operative surgical site infection rates.

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Background and purpose: One of the most common complications of catheter in hemodialysis patients is infections and many methods have been proposed to prevent it. This study compared the effects of heparin lock-antibiotics and heparin to prevent infections in patients undergoing hemodialysis. Materials and methods: This single blind clinical trial included 122 patients who were randomly assigned to receive heparin lock (group A) or heparin-antibiotic lock (group B). The subjects in each group were matched for the presence or absence of risk factors. Occurrence of any of the four symptoms of fever, chills (if no other obvious source of infection was found), redness, purulent discharge was considered catheter-site infection. The medication regimens were cefazolin (5 mg/dl) and heparin 2500 IU/ml. Results: The mean age of patients in Group A and B were 57.12 ± 17.34 and 57.61 ± 19.64 years, respectively (P= 0.088). The patients who developed infections included 22 (36%) patients in group A and 11 (18%) patients in group B (P= 0.02). Conclusion: Heparin-cefazolin lock in group B considerably decreased the incidence of catheter infection. Therefore, it could be used as an effective method to prophylaxis of hemodialysis catheter infection.

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Background and purpose: Inappropriate and irrational prescription of antimicrobial agents is a major concern around the world. Almost half of the prescribed antibiotics are inappropriate and unreasonable. Widespread use of Aminoglycosides is seen in the northern region of Islamic Republic of IRAN. This study aimed at investigating the consumption patterns, indications for use, dosage and intervals, complications, and monitoring of this class of drugs. Materials and methods: This retrospective study has been done in 100 patients who received amikacin in Sari Buali-sina Hospital, 2011. Demographic and other information regarding the time of starting antibiotic therapy, antibiotic therapy duration, amikacin dosage and interval, and creatinine clearance were recorded. SPSS V.16 was used to analyze the data. Independent samples t-test and chi square were used to compare the quantitative and qualitative variables, respectively. Results: Among the patients 53 (53%) were less than one week of age, of whom 61% were male. The mean of starting antibiotics was 1.06 ± 0.307 days in neonates, and 1.19±0.616 days in infants. The mean duration of starting treatment with antibiotics in neonates was 12.95± 12.237 days and 6.57± 4.01 in infants. The average duration of amikacin in neonatal and infants was 4.89±4.05 and 9.83± 5.43 days, respectively. Serum creatinine levels were measured in17 patients before, during and after using amikacin. In 30% of patients the correct dosage based on serum creatinine levels was not prescribed. The mean of baseline serum creatinine was 0.603 ± 0.122 in neonates and 0.625 ± 0.103 in infants (Pv=0.95). Conclusion: This study showed irrational use of amikacin and the main problem found in this study was not considering renal function, co-administration of drugs, and nephrotoxic. We believe that referral centers should be created in the region on a daily basis in order to measure the drug level.

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Background and purpose: Due to the emergence of antibiotic resistance bacteria, treatment of urinary tract infection is becoming more problematic. Integrons are mobile genetic elements that play an important role in dissemination and accumulation of resistance genes of multidrug resistance in bacteria. The aim of the present study was to determine the antibiotic resistant profile, frequency of integron genes (Classes 1,2,3) and investigate the role of integrons in the development of antibiotic resistance among Escheria coli and Klebsiella pneumoniae isolated from urinary tract infections. Material & methods: 50 E.coli and 50 K.pneumoniae isolated from the urine samples of patients who referred to Valiasr Hospital, Arak, Iran were subjected to this study. All the isolated samples were confirmed by standard biochemical tests. Isolates were tested for susceptibility to 16 antimicrobial drugs by using disk diffusion method and the distribution of different integron classes was determined by polymerase chain reaction (PCR). Results: The highest rate of antibiotic resistance in K. pneumoniae isolates was found in rifampin (90%), erythromycin (90%), ceftriaxone (76%), amoxicillin-Clavulonic acid (76%), cotrimoxazole (70%), cefotaxime (70%) ceftazidime (66%) and for E.coli isolates in cotrimoxazole (88%), ceftriaxone (76%), amoxicillin-Clavulonic acid (74%), ceftazidime (72%) and cefotaxime (72%). All the E.coli isolates were susceptible to Imipenem, while only three (6%) of K.pneumoniae isolates were resistant to this antibiotic. Ninety percent of K.pneumoniae and 86% of E. coli isolates carried class 1 integrons, whereas class 2 integrons were found in 8% and 2% of E. coli and K.pneumoniae isolates, respectively. Class 3 integrons were not found. Conclusion: The high frequency of Class 1 integron in E.coli and k. pneumoniae isolates associated with the high rate of antibiotic resistant indicate that may be integrons play an important role in facilitating the spread of antimicrobial resistance in this region.

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Background and purpose: Resistance to choice antibiotics is serious and focus of concern. Therefore, the current study was done to identify the enterococcus resistance pattern to Linezolid- choice antibiotic, which has not yet been used in the country. Material and methods: This descriptive study was a laboratory research done on 100 stool samples gathered from hospitalized patients of Shahid Beheshti Hospital, Kashan, 2012. The samples were transferred to the university microbiology laboratory in transport media and the entrococcus identity was established through biochemical tests. Then Linezolid and Vancomycin antibiogram was recorded by means of Disk Diffusion method. On the other hand, Minimum Inhibition Concentration (MIC) for Vancomycine was measured by E-test method. Finally, the results were analyzed by means of SPSS software- Chi square test, and paired T-test. Results: The mean age was 52.26±18.29 years old. Forty eight subjects were females (48%) and the rest were males. Thirty four subjects were colonized with Vancomycine Resistant entrococci and 33 others with Linezolid Resistant entrococci. Using the E-test method, 73 strains were sensitive to vancomycine (MIC≤4g/ml), 27 resistant (MIC>33g/ml), and none was intermediate. Using antibiotic was one of the most important risk factors for vancomycine resistance in enterococci (P<0.05). The duration of antibiotic use with Linezoid in the past was the only effective factor in resistance (P<0.05). Conclusion: The resistance rate of enterococci was 33%, without any history of linezolid use in the past, this can conclude that sort of cross resistance to both vancomycine and linezolid, synchronically that suggests the necessity of future studies about genome basics of the issue.

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Background and purpose: Urinary tract infection (UTI) is one of the most common infections and the second cause of infection in human body. In developing countries it involves at least 250 million people annually. The main cause of this infection is gram negative bacteria such as E coli. UTI is seen in all ages and both sexes but its incidences is more in female. The base of treatment for urinary tract infection is administrating an appropriate antibiotic. Today, antibiotic resistance is considered as an important challenge in treating infections. High and unnecessary use of antibiotics especially in urinary infections resulted in resistance to some antibiotics. Therefore, this study was designed to assess the antibiotic susceptibility patterns of Ecoli strains isolated from urine samples of urinary infected patients. Material and Methods: In this study urine samples were collected applying Midstream clean catch method and cultured in blood agar and EMB medium using standard loop then incubated for 24hr in 370. Results: During 12 months, 1147 samples were studied of which, 208 samples were reported positive. The rate of positive cultures was found higher in women and their mean age was less than that of men. The main antibiotics resistant to Escherichia coli were nalidixic acid, cotrimoxazole, and cefazolin and the most sensitivity was found with imipenem, nitrofurantoin, and piperacillin. Conclusion: According to this study, urinary infection of Ecoli is more common amongst women of younger ages. In this study Ecoli showed lower resistance to imipenem, nitrofurantoin and piperacillin. Therefore, these antibiotics are the most effective in controlling Ecoli.

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Background and purpose: Nosocomial infections are a major health problem worldwide. Hospital environment is a reservoir for nosocomial pathogens. This study aimed at determining the prevalence of antimicrobial resistance pattern of bacteria isolated from the environment and medical equipment in Valiasr Hospital in Arak. Material and Methods: A total of 210 samples was collected from hospital and identified. Inducible clindamycin resistance in Staphylococcus was determined with D Zone and sensitivity to vancomycin was identified by using Mueller Hinton agar and E-test. The sensitivity of these strains to cefoxitin and oxacillin was determined by disk diffusion method. The resistance was confirmed by investigating the presence of mec A gene using PCR technique. To identify the ESBL producing gram-negative bacill standard method was used. Amp C beta lactamase resistance was assessed by Amp C disk test, and for carbapenemase resistant MHT was applied. E-test with imipenem and imipenem+EDTA were used to identify the resistance pattern of metalo beta lactamase. Results: There were 240 isolates of which 185 (77%) were Staphylococcus. Among these isolates 136 (73.5%) were resistant to oxacillin and cefoxitin. Inducible clindamycin resistance was found in 46 (25%) isolates. Two samples of the Staphylococcus epidermidis were vancomycin resistant. The presence of Sa442 genes in Staphylococcus aureus and the mecA gene of MRSA was confirmed in all isolates expect in two. The frequency of gram-negative bacteria was 55(23%). ox51 gene was identified in acinetobacter baumannii. Fifteen nonfermenting gram-negative bacill and 40(65%) strains of Enterobacteriaceae were ESBL producers. Among the Klebsiella pneumoniae six (33.33%) were AmpC producers. MHT positive was found in nine (60%) nonfermenting bacills. Conclusion: According to this study presence of microorganisms in Valiasr Hospital environment and high incidence of antibiotic resistance are considered as major health problems. By determining potential pathogens in hospital setting and the pattern of antibiotic resistance markers physicians can perform more successful treatments.

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Background and purpose: Multi-resistant enterococci are important nosocomial pathogens that are shown to have high prevalence in recent years. Knowledge of antimicrobial resistance pattern is essential to formulate treatment guidelines for infections caused by enterococci. The aim of this study was to investigate the antimicrobial resistance among enterococci isolated from Hamedan hospitals. Material and methods: The study was carried out during 2012-2014 in 242 Enterococcus faecalis and Enterococcus faecium Strains isolated from clinical specimens of teaching inpatients and outpatients hospitals in Hamedan. Identified species by biochemical methods were confirmed by PCR. Antibiotic resistance was performed by disk diffusion. MIC (Minimum Inhibitory Concentration) of vancomycin and Teicoplanin were determined by Microdilution Broth method. Results: A total of 280 enterococcal isolates were studied of which, 175 (62.5%) were identified as Enterococcus faecalis, 67(24%) as Enterococcus faecium, and 38(13.5%) as Enterococcus spp. No resistance to Linezolid and Nitrofurantoin was detected among E.faecalis isolates. All isolates of E. faecium were susceptible to Linezolid. Resistance rates to ampicillin, Vancomycin, Teicoplanin, ciprofloxacin, erythromycin, Norfloxacin, gentamicin and Nitrofurantoin were found higher in E.faecium isolates than those of the E.faecalis group. Conclusion: Due to the high prevalence of Vancomycin-resistant enterococci and also increasing resistance of enterococcus to most common antibiotics, there is a need for preventive and control measurements. Therefore, antibiotic susceptibility testing is recommended for all patients before prescription of appropriate antibiotics.

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Background and purpose: An increasing emergence of multidrug resistance among Klebsiella pneumoniae nosocomial isolates has limited the therapeutic options for treatment. The beta-lactamases are the major defense of gram-negative bacteria against antibiotics. The aim of this study was the detection of ESBLs and Amp-C enzymes and MOX, FOX, and ACT genes in K.pneumoniae strains isolated from hospitalized patients in Tehran hospitals during 2011-2013. Materials and methods: This study was conducted in 120 K. pneumoniae isolates from Imam Hossein, Taleghani and Mofid Children's hospitals in Tehran, Iran. Antibiotic susceptibility tests were performed using Kirby-Bauer disc diffusion and Broth Microdilution methods. The detection of Amp-C and ESBLs enzymes was carried out according to CLSI guidelines. The MOX, FOX, and ACT genes were detected by PCR and sequencing methods. Results: Among 120 K. pneumoniae strains, 24 (20%) and 68(56.8%) were Amp-C and ESBL positive, respectively. In this study colistin and tigecycline were found more active than other antibiotics. ACT, FOX, and MOX genes were detected in 16 (13%), 46 (38.33%) and 43(35.83%) of the isolates, respectively. Conclusion: The prevalence of antibiotic resistance genes detected in this study is of great concern and highlights the need for infection control measures including antibacterial management and identification of resistant isolates.

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Antibiotics residues in animal derived food products are a great concern for public health. The major risk associated with this problem is drug resistance in pathogenic bacteria in consumers.This survey is a comprehensive review of many studies carried out by scientists in Iran in food hygiene, livestock breeding and toxicology over the last thirty years. Food samples were examined by different analytical methods. Data was collected from databases including pubmed, science direct, SID, magiran, etc.High levels of antibiotic residues in food products need revision of national standards for antibiotic residues in these products. Also, application of appropriate techniques for measuring antibiotic residues in food products in Iran is essential for quality control.

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Background and purpose: The increasing emergence of multidrug resistance among Klebsiella pneumoniae nosocomial isolates has limited the therapeutic options in treatment of infections caused by these bacteria. The beta-lactamases, efflux pumps and porins constitute the major defense mechanisms of antibiotic resistance of these bacteria. The aims of the present study were detection of OqxA and OqxB genes, evaluation of expression level of OqxA efflux pump and also determining the genetic basis of resistant K. pneumoniae strains isolated from hospitalized patients in Mofid and Taleghani hospitals during 2011-2012. Materials and methods: This study was conducted in 100 K. pneumoniae isolates from Taleghani and Mofid hospitals in Tehran, Iran. Antibiotic susceptibility tests were performed by Kirby- Bauer disc diffusion and Broth Microdilution methods according to CLSI guidelines. Detection of extended spectrum beta-lactamases was done by a kit developed by MAST group. The Modified Hodge Test (MHT) was used to identify carbapenemase production among the isolates. The OqxA and OqxB genes were detected by PCR and sequencing methods and oqxA gene expression was analyzed using realtime RT–PCR. PFGE typing was then performed for further analysis of the resistant isolates. Results: Among 100 K. pneumoniae isolates, 5(5%) were KPC positive and 48(48%) were ESBL positive. In this study, fosfomycin, colistin and tigecycline were found more effective than other antibiotics. The prevalence of both oqxA and oqxB genes detected among the K. pneumoniae isolates was 50 (50%). RT– PCR revealed higher expression (2.3-fold) in isolates with reduced susceptibility to Ciprofloxacin. Isolates belonged to three clusters and some of them belong to a particular clone. Conclusion: The prevalence of antibiotic resistance genes identified in this study highlights the need for more infection control measures including antibacterial management and identification of resistant isolates.

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Background and purpose: Methicillin-resistant Staphylococcus aureus (MRSA) isolates are the most common pathogen that causes hospital and community acquired infections. Studying on drug resistance, it is important strategy to prevent these types of infections. The use of molecular typing methods is essential for determining the origin of the strains and also in epidemiological investigations. The aim of present study was to survey the molecular characteristics of Staphylococcus aureus (SA), to detect mecA gene, and typing SCCmec in the strains isolated from staffs in Vali-aser and Mousavi hospitals in Zanjan province. Materials and methods: This descriptive study was carried out on 104 SA isolates collected from the clinical samples at Vali-aser and Mousavi hospitals. The identification of all tested isolates were confirmed by Gram's stain, coagulase and manitol salt agar and the isolates were tested for antibiotic resistance by the disc-diffusion method. In addition, the genotypes of SCCmec in the MRSA isolates were determined by multiplex PCR and the results were analyzed using the chi-square. Results: The highest resistance was shown against oxacillin, penicillin, tetracyclin and co-trimoxazole and the most sensitive antibiotics were amikacin and ciprofloxacin and all of the isolates were sensitive to vancomycin and all of the isolates were resistant to at least three classes of antibiotics. Five (8.6%) MRSA strains were SCCmec type I, 11 (19%) were type II, 20 (34.5%) were type III, 17 (29.3) were type IV-a, 1 (1.7%) were type IV-b, 2(3.4%) were type IV-c, 11 (19%) were type IV-d and 18(31%) were type V. Overall, 19 (32.7%) MRSA strains could not be typed. Conclusion: Our findings show that clinical isolates of MRSA in our hospital carrying various types of staphylococcal cassette chromosome mec (SCCmec) types. SCCmec typse III and V were the predominant strain of MRSA identified.

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Background and purpose: Wastewaters are the most important sources of antibiotics entrance into the aqueous environments. Conventional wastewater treatments cannot eliminate these micropollutants and antibiotic resistant bacteria. The aim of this study was to determine the antibiotic resistance pattern in bacteria isolated from untreated sewage and effluent of municipal wastewater treatment plant in Tabriz. Materials and methods: In this cross sectional study, in addition to counting the number of different types of bacteria in raw sewage and municipal wastewater effluent, various bacteria including Enterobacteriaceae and Staphylococcus, Bacillus and Pseudomonas were identified using specific mediums, API E20 kits and biochemical tests. Susceptibility test of bacteria to antibiotics was determined by Kirby-Bauer's disc diffusion. Results: The results showed lower than one log removal efficiency for coliforms bacteria by the wastewater treatment plants. The difference in the number of colonies apart from staphylococci was not significant in wastewater influent and effluent. Aeromonas and staphylococci were the most frequent bacteria in wastewater influent and effluent, respectively. Enterobacteriaceae were generally more sensitive than other bacteria. Resistance to antibiotics was found to be higher in the penicillin member of antibiotics. Resistant to four antibiotics including cephalexin, ampicillin, methicillin and amoxicillin were between 60 to 100%. The resistance of all species increased in the effluent of wastewater treatment plant. Conclusion: Growth and survival of antibiotic resistant bacteria increases in wastewater treatment plants and conventional treatment processes do not demonstrate enough efficiency for removal of these strains.

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Background and purpose: Some complications such as infective endocarditis may develop following dental procedures. Preventing infective endocarditis is possible by identifying and eliminating the underlying risk factors. This study was designed to investigate the risk factors for infective endocarditis. Materials and methods: In a cross sectional study we investigated 60 patients with infective endocarditis attending Rajaie Heart Center and Imam Khomeini Hospital, Tehran. All parameters were recorded including the type of endocarditis, history of cardiac diseases, cardiac surgery, infective endocarditis, intravenous drug abuse, any kind of systemic disease, and microorganisms in blood cultures. Other information including oral health behavior, history of dental procedures and DMFT index were also recorded. Data was analyzed using descriptive statistics. Results: The mean age of patients was 16.8±42.9 years and 70% had heart diseases. Other factors including cardiac surgery, intravenous drug abuse, history of endocarditis, and other surgical procedures were also observed. Systemic diseases were found in 50%. In 36.7% no risk factor was found for increased risk of endocarditis. Dental treatments were reported in 73.3% of the patients. The mean DMFT score was 36.6 ± 4.12. In the past 6 months 16.7% had dental procedures that required antibiotic prophylaxis. Conclusion: The low age of patients, high number of patients without underlying risk factors and poor oral hygiene are amongst the important issues that require further investigation.

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Background and purpose: Resistance to antibiotics has decreases the performance of antibiotics and has dramatically increased over the past few years. This has led to increasing interest towards discovery and introduction of new antibiotic compounds, especially plant-derived compounds. The aim of this study was to investigate the antibacterial activity of the methanol extracts from different parts of Prangos crossoptera against pathogenic bacteria and their drug synergistic and antagonistic with standard antibiotics. Materials and methods: Antibacterial activity of methanol extracts from different parts of Prangos crossoptera was investigated against Proteus mirabilis, Proteus vulgaris, Streptococcus sobrinus, and Staphylococcus saprophyticus in 250 to 3000 µg/ml concentrations by disc diffusion and micro-broth dilution methods. Then, the MIC and MBC values and inhibition zone of all extracts were measured. The synergistic effects of the most efficient concentration were studied on four common antibiotics. Results: All tested extracts, especially the flower, exhibited significant antibacterial activity against studied bacteria. The flower extract also showed synergistic effect on penicillin and ampicillin activity but did not influence the performance of gentamicin and streptomycin. Conclusion: The P.crossoptera has significant antibacterial effect and could increase the activity of penicillin and ampicillin.