International Journal of Enteric Pathogens
Volume:2 Issue: 2, May 2014

Development of resistance to many of the commonly used antibiotics is an impetus for further attempts to search for new antimicrobial agents.. In the present study, the antibacterial activity of Saturejahortensis essential oil against multi-drug resistant bacteria isolated from the urinary tract infections was investigated.. During the years 2011 to 2012 a total of 36 strains of pathogenic bacteria including 12 Klebsiellapneumoniae, 12 Escherichia coli and 12 Staphylococcus aureus species were isolated from urine samples of hospitalized patients (Amir Al-Momenin Hospital, Zabol, South-eastern Iran) suffering from urinary tract infections. After bacteriological confirmatory tests, the minimum inhibitory concentrations of the essential oil of Saturejahortensis were determined using micro-dilution method.. The antibiotic resistance profile of the E. coli isolates were as follows: ceftazidime (50%) cefixime (41.6%), tetracycline (75%), erythromycin (58.3%). However K. pneumoniae isolates showed resistance to ceftazidime (33.3%), cefixime (58.3%), erythromycin (75%) and S. aureus isolates were resistant to cefixime (33.3%), trimethoprim-sulfamethoxazole (41.66%), penicillin (50%), oxacillin (83.3%), ceftazidime(66.6%) and vancomycin (8.3%). The essential oil of this plant had inhibitory effect against most isolates. More than 1/3 of the E. coli isolates showed the lowest MIC (10 ppm) whereas more than 1/3 of the K. pneumoniae isolates showed the highest (250 ppm) MIC values. In contrast, equal number of S. aureus isolates showed the low MIC values (10 and 50 ppm), while the heighest MIC (250 ppm) was seen in 1/3 of isolates and moderate MIC (100 ppm) was seen in one isolate only.. The Saturejahortensis essential oil has a potent antimicrobial activity against multi-drug resistant bacteria. The present study confirms the usefullness of this essential oil as antibacterial agent but further research is required to evaluate the practical value of this plant before proving its therapeutic applications..

Medicinal plants have now attracted more attention due to their antibacterial activity and also increasing antibiotic resistance among bacteria. Native plants of each region are potential resources for this purpose.. The aim of the present study was to detect the antibacterial effect of Eucalyptus microtheca (Myrtaceae family) which is currently used as an antibacterial fumigation medicine.. Using standard disk diffusion method, the antibacterial activity, MIC, and MBC indexes of alcoholic extracts from this plant were tested on some pathogenic bacteria. The structural changes following the exposure to these extracts were also investigated in test bacteria.. Significant antibacterial activity was found against gram-positive and gram-negative bacteria, which among them, Escherichia. coli and Pseudomonas. aeruginosa showed the most sensitivity and Staphylococcus. aureus the least. The value of MIC and MBC for both extracts was 8 mg/mL for E. coli, while they were 8 mg/mL and 16 mg/mL for Bacillus cereus, respectively. Both MIC and MBC values of methanolic and ethanolic extracts against P. aeruginosa were 8 and 16 mg/mL respectively. SEM revealed structural changes in the affected bacteria that suggest the cell wall was the main target site of active constituents.. It can be concluded that this plant has potential application in infection control, especially against E. coli and P. aeruginosa and regarding their recent reported epidemic, this plant can be a good choice for antibiotic discovery..

Garlic (Allium sativum L.) exhibit a broad-spectrum of antimicrobial activity against both gram negative and gram-positive bacteria. Helicobacter pylori (H. pylori) is the main factor in peptic and duodenal ulcer diseases. Some strains of H. pylori have become resistant to the current antibiotics.. The purpose of this study was to determine the antibacterial effects of garlic on H. pylori.. The gastric biopsies were inoculated on Brucella agar base (Conda Pronadisa, Spain) supplemented with 5% sterile sheep blood, 7 % fetal calf serum, vancomycin (5 mg/L), trimethoprim (5 mg/L), and polymyxin B (2500 U/L). Antibiotic susceptibility to garlic and commercial antibiotic disc was determined by agar disc diffusion method.. In this study, ten strains of H. pylori out of 120 samples were isolated. The minimum inhibitory concentration of garlic extract for all isolates ranged between 25- 400 mg/mL. Resistance rates of 10 strains of H. pylori to amoxicillin, ciprofloxacin, clarithromycin, metronidazole, and tetracycline were 20%, 20%, 30%, 60%, and 30%, respectively.. In this study, the antibacterial effect of aqueous extract of garlic on all H. pylori clinical isolates was confirmed. These findings might help us to use a new strategy for treatment of peptic ulcer..

Antibiotic resistance among bacteria is a worldwide problem. Enterobacteriaceae resistance to third-generation cephalosporins is typically caused by the production of β-lactamases.. The aim of this study was to determine antimicrobial susceptibility of environmental Enterobacteriaceae isolates from Karun River in Iran.. A total of 600 water samples were collected from nine stations along Karun River in Iran, during spring and summer of 2012. In this research, different waterborne bacterial pathogens were isolated and identified using the membrane filtration technique and analytical profile index system for Enterobacteriaceae (API 20E). Then, disk diffusion method (CLSI, 2010; M2-A9) was used for testing the antibiotic resistance susceptibility. Enterobacteriaceae genera were tested against sixteen antibiotics: ampicillin, carbencillin, methicillin, cephalothin, cefotaxime, vancomycin, amikacin, ofloxacin, kanamycin, tetracycline, erythromycin, clindamycin, norfloxacin, nitrofurantoin, chloramphenicol, and amoxycillin.. The results of this study suggested that the level of fecal contamination in Karun water was very high. Among the isolated Enterobacteriaceae, there were 287 strains of (65%) Escherichia coli, 162 (27%) Enterobacter aeogenes, 73 (12.16%) Citrobacter freundii, 58 (9.66%) Proteus vulgaris, and 20 (3.3%) Salmonella typhi. All Enterobacteriaceae isolates showed 100% resistance to ampicillin, carbenicillin, methicillin, vancomycin, erythromycin, clindamycin, and tetracycline. They failed to exhibit resistance to norfloxacin and ofloxacin. Other antibiotics showed intermediate activity, and some isolates were resistant.. Detection of fecal indicator bacteria (E. coli) in more than 75% of water samples indicates the possible presence of other bacteria causing infectious diseases..

Diarrheal illnesses caused by Salmonella and Shigella spp remain a serious public health problem in industrializing countries, and are still an important cause of morbidity and mortality in developed as well as undeveloped countries. Rapid detection of agents that cause diarrhea may help prevent occurrence of outbreaks.. The aim of this study was to compare conventional biochemical tests, namely API 20E strip system and Polymerase Chain Reaction (PCR) for identification of Salmonella enterica and Shigella spp. isolated from stool samples of patients with diarrhea.. Stool samples were collected from patients with diarrhea during a three-year period (2009-2012). Conventional biochemical tests were used for identification of Shigella spp. and Salmonella enterica isolates. API 20E strips and PCR methods with oligonucleotide primers specific for ipaH of Shigella genus and hilA of Salmonella enterica were used to confirm the identity of the isolates.. Of the 81 suspected S. enterica and 112 Shigella spp. identified by conventional biochemical tests, 77 and 105 were identified as S. enterica and Shigella spp. by API 20E, respectively. All of the isolates were assigned to bacterial species with 99.9% probability value. All of the 81 suspected Salmonella enterica isolates produced 784 bp amplification bands of hilA gene. Among the 112 Shigella isolates confirmed by PCR, 90 (80.35%) were positive for wbgZ and 14 (12.5%) were positive for rfc genes indicative of S. sonnei and S. flexneri, respectively.. In conclusion, the results of this study suggest that the PCR amplification of hilA and ipaH is a promising method for identification of Salmonella enterica and Shigella spp. The outcomes of this study can help towards more accurate and easy screening of large population of patients with Salmonella enterica and Shigella spp infections.

To study prevalence of Campylobacter spp. in chicken and beef meat, and determine the drug susceptibility of strains, 450 samples in Tehran, Iran were investigated.. This study aimed to determine the prevalence and the antimicrobial resistance of entropathogenic Campylobacter strains, especially C. jejuni isolated from raw chicken and beef meat in Tehran- Iran.. Out of 250 chickens and 200 beef meats, 121 (26.8 %) contaminated cases with Campylobacter strains were isolated. Campylobacter was isolated from a significantly larger number of chickens (44%) than beef meats (5.5 %) (P < 0.05).. From all isolated Campylobacter organisms, 93 (76.8%) species were identified as C. jejuni and 28 cases (23.1%) as C. coli. Susceptibilities of 121 strains (93 C. jejuni and 28 C. coli) were determined against 12 antimicrobial drugs using the disk agar diffusion method. Resistance to nalidixic acid (75%) and ciprofloxacin (50%) was an alarming finding, moreover, 32.6% of isolates was resistant to tetracycline, 10.8% to ampicillin, 29.3% to colisitin and 26.1% to amoxicillin. The highest sensitivity was seen to erythromycin (95 %) and gentamicin (96%).. These results showed that a high proportion of chicken and beef meat in Iran is contaminated with Campylobacter, particularly with Campylobacter jejuni. The high rate of contamination, especially chicken is a significant public health concern. Most of the isolates were resistant; therefore, human infection with Campylobacter spp. via consumption of these products is possible..

Symptomatic bacteraemia, is a frequent condition among cancer patients with a significant morbidity and mortality all over the world.. The aim of this study was to determine the burden of enteric pathogens causing bacteremia among cancer patients..Patients and Ten ml blood samples were withdrawn from the cancer patients under aseptic conditions. The blood specimens were added to the blood culture bottles and incubated at 37°C. The bacterial isolates from these samples were identified by routine biochemical reactions.. During the study period, 68 blood samples from cancer patients were analyzed for bacteremia. Of these patients, six were female (08/82%) and 62 were male (91.18%); with age ranging from under 40 years to 85 years old (mean, 63 years). Gastro-intestinal cancer and cancers of head and neck were the most frequent cancer types in the studied group, accounting for 51 (75%) and 15 (22.1%) cases, respectively. The mean weight of patients was 69.18 Kg (range: 49-100 Kg). Similarly, the mean length of hospital stay was 8 days (range: 4-12 days). Positive blood cultures were detected in only 12 (17.65%) and 11 (91.7%) blood specimens from the Cancer Institute, Tehran, compared with one (08.33%) from Shahid Kamali hospital, Karaj. From these patients, 15 bacteria were isolated; E. coli alone outnumbered other species and accounted for 33.33% of the episodes of bacteremia.. In conclusion, our investigation revealed that cancers of GI tract are the most common cancer types causing bacteremia and also we identified that most common bacteria causing bacteremia in Cancer Institute, Tehran and Shahid Kamali Hospital, Karaj, are E. coli and S. aureus.

There is an increasing interest in search for antimicrobial peptides (bacteriocins and bacteriocin-like compounds) produced by lactic acid bacteria (LAB) because of their potential to be used as antimicrobial agents for improving the safety of food products.. The main objective of study was to evaluate the antibacterial potential of locally isolated Lactic Acid bacteria (LAB) and determine their bacteriocin producing ability in in-vitro conditions.. The antibacterial activity of 77 isolated LAB strains was tested against a number of pathogens by well-diffusion method. The isolates demonstrating antimicrobial potential were selected and tested for the production of bacteriocin or bacteriocin like substance. The bacteriocin produced by two of the isolates were partially purified and characterized.. The results indicated the neutralized supernatant fluid of two of the isolates identified as L. brevis LB32 and L. pentosus LP05, were active against the growth of Listeria monocytogenes, Salmonella enteritidis, Shigella dysenteriae, Staphylococcus aureus and Streptococcus pneumoniae. Additionally, L. brevis LB32 was able to inhibit the growth of Salmonella typhi and Klebsiella pneumoniae, while, S. pnuemoniae and L. monocytogenes appeared to be the most sensitive strain as apparent by highest zone of inhibition against these pathogens, respectively. The antimicrobial activity in the supernatant fluids of the mentioned strains remained unaffected after treating with enzymes catalase, lipase and lysozyme, while were strongly sensitive to the action of proteolytic enzymes, suggesting the presence of bacteriocin like inhibitory substance (BLIS) in the two isolates. The inhibitory substance produced by the two isolates appeared heat resistant and tolerated 100˚C and 121˚C for 55 minutes and 20 minutes, respectively. Partial purification of the concentrated culture supernatant fluids of L. brevis LB32 and L. pentosus LP05 by ammonium sulphate (80%) and DEAE cellulose columns resulted in an enhanced activity (AU/mL) and yield. Using different pore size ultra filter membranes and SDS-PAGE analysis, the approximate molecular weight of the BLIS produced by L. brevis LB32 and, L. pentosus LP05 appeared to be approximately 4.5 and 6 KDa, respectively. In contrast to L. brevis LB32, L. pentosus LP05 harbored an 18Kb plasmid DNA which appeared to be carrying the bacteriocin gene as evident by plasmid curing experiments. All the mutants retained their host immunity and were resistant to the bacteriocin produced by the parent strain.. In conclusion, the antibacterial activity possessed by these isolates might be used for the control of unwanted pathogens mainly in dairy products, and could be investigated further for using in fermented dairy products..

Helicobacter pylori related-infections are common in developing countries, including Iran. However, little information is available on the antibiotic susceptibility of H. pylori in Yazd.. The aim of this study was to investigate the antibiotic resistance patterns of H. pylori isolates from gastric biopsy of patients in Yazd.. In this descriptive-analytical study, 651 gastric biopsy specimens were taken from May 2012 to February 2013. Samples were cultured into selective Brucella agar media. After 3 to 10 days of incubation and identification of bacteria by using gram stain and biochemical tests, antibacterial susceptibility assay was performed by disk diffusion method.. All of 651 gastric biopsy specimens were cultured and 144 (22.12%) isolates of H. pylori were collected. In total, 76 (52.7%) of 144 H. pylori isolates were isolated from females and 68 (47.2%) from males. Rate of antibiotic resistance to metronidazole, tetracycline, clarithromycin, levofloxacin, ciprofloxacin and amoxicillin were 77.8%, 21.5%, 18.8%, 14.6%, 19.4% and 7.6%, respectively. No antibiotic resistance was found against furazolidone. There was no significant association between these isolates antibiotics resistance with sex, age and endoscopic diagnoses (P > 0.05).. H. pylori isolates resistance was high to antibiotics, especially metronidazole. Therefore, determining resistance pattern of H. pylori isolates is recommended in all parts of the country..

The nanoparticles synthesis through biological processes is evolving a new era of research interests in nanotechnology. In usual methods silver nanoparticles are synthesized through chemical methods, having extremely toxic and flammable natures.. The aim of the present study was to synthesize silver nanoparticles, through the green method of utilizing Sesamum indicum (S. indicum) extract and to determine the potential antibacterial effects of the product against multi-drug resistant Escherichia coli (E. coli).. The formation and characterization of AgNPs (silver nanoparticles) were confirmed by UV-vis spectroscopy, energy-dispersive spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscope (TEM). All 30 strains of E. coli were isolated from urine cultures of hospitalized patients (Amir Al-Momenin Hospital, Zabol, South-Eastern Iran) with urinary tract infection, 2011-2012. The minimum inhibitory (MIC) concentrations were investigated by microdilution method.. The results showed that isolated E. coli were resistant to four different antimicrobial agents including ceftazidime (26.6%), cefixime (40%), tetracycline (63.3%) and erythromycin (56.6%). The highest MIC value for produced nano silver in S. indicum seed extract, was 200 ppm, against five isolates of E. coli.. Considering the sufficient antimicrobial activities of nanoparticles tested in this study, they are suggested for enterobacterial infection treatment, especially in hospital environment..