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

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.

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

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.

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.

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.

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.