[Molecular evaluation of the 2'-aminoglycoside nucleotidyltransferase gene in Escherichia coli isolates that produce hemolysin and are sensitive to mannose type I pili and P]

Aminoglycosides are highly potent, broad-spectrum antibiotics with many desirable properties for the treatment of life-threatening infections. Escherichia coli [E. coli] is the most common cause of urinary tract infection [UTI]. Antibiotic resistance has recently become prevalent. Enzymatic inactivation of aminoglycosides by aminoglycoside-modifying enzymes is the main mechanism of resistance to these antibiotics in E. coli. The main purpose of this research is to evaluate the presence of the 2'-aminoglycoside nucleotidyltransferase [ant[2"]-Ia] gene in E. coli isolates sensitive to mannose and hemolysin production. After collecting 276 E. coli isolates from patients that referred to Tehran Heart Center, we used the disk diffusion method to determine the resistance patterns of isolates toward Gentamicin, Tobramycin, Kanamycin, Amikacin and Netilmicin antibiotics according to the CLSI principles. We evaluated hemolysin production by assessing the ability of the isolates to grow on sheep and human blood agar media. Chromosomal DNA of the isolates was extracted using DNA extraction kits and PCR method used for the detection of the ant[2"]-Ia gene. In order to study mannose sensitivity we used human RBCs. Results obtained from antibiotic resistance determination tests showed that the highest rate of resistance was observed against tobramycin [24/63%]. Of those resistant, 6% could produce hemolysin in both sheep and human blood agar media. Mannose sensitivity was observed in 14% of isolates during agglutination. There were 24.63% of E. coli isolates resistant to Tobramycin, 23.18% resistant to kanamycin, 21.01% resistant to gentamicin, 6.15% resistant to netilmicin and 3.62% resistant to amikacin. ant[2"]-Ia gene was detected in 47.88% of E. coli isolated from urine. Due to the high prevalence of urinary tract infections caused by uropathogenic E. coli [UPEC] strains and the increasing rate of antibiotic resistance, periodic evaluations should be conducted for outbreaks of resistance in order to select the most suitable treatment to prevent routinely increasing antibiotic resistance

[Anti bacterial scaffolds based on gum tragaccanth for wound caring under moist conditions]

When hydrocolloids dressings are loaded with an antibacterial agent, they can also prevent infection during wound cicatrisation. To consider interesting properties of traditional Gum Tragacanth such as moisture absorption, hydrocolloid formation, drug holding and releasing abilities, it was aimed to introduce a scaffold wound dress based on Gum Tragacanth with drug release ability simultaneously. In this experimental study, gum tragacanth from Astragalus gossypinus species [Iranian species] is solved and loaded with an aminoglycoside antibiotic [Gentamicin]. Prepared solution transformed to a nano fibers network "scaffold" by lyophilization method. Samples were characterized by scanning electron microscopy, fourier transform infrared and X-ray diffraction methods and their antimicrobial and moisture holding properties were determined. Gum tragacanth showed a proper potential for dispersing gentamicin and the drug was loaded into polymer matrix without any aggregation. Loaded gum tragacanth with gentamicin is successfully transformed to a nanofibers scaffold by lyophilization. The diameters of fibers were in the range of 300nm to 2micro m. Transformed gum tragacanth into scaffolds showed declined regain content [up to 50%] due to the ordering and orientation of polymer chains. Ordered hydroxyl groups also observed in FTIR graphs. Regarding the zones of inhibition, scaffolds also showed acceptable antibacterial activities. Produced scaffolds are capable of absorbing wound's exocrine liquid easily due to their high specific area of nanofibers. When it is turned to gel by moisture sorption, the release of loaded Gentamicin would be enhanced

[Evaluation of antifungal activity of essential oils of Thymus vulgaris, Petroselinum Crispum, Cuminum cyminum and Bunium persicum on candida albicans in comparison with Fluconazole]

Nowadays notable increase in acquired resistance of Candida species to antifungal drugs and necessity of using agents with antifungal properties is unavoidable. In some plants due to presence of components such as polyphenols have antimicrobial properties. In this study antifungal effects of essential oils of Thymus vulgaris, Petroselinum crispum, Cuminum cyminum and Bunium persicum on standard strain of Candida albicans were evaluated. 25 grams leafs of the Thymus vulgaris and Petroselinum crispum and seeds of the Cuminum cyminum and Bunium persicum were dried and grinded after that the essential oils of each mentioned plant were prepared by Clevenger system. Serial dilutions of essential oils were made in 96 well microtiter plates. Minimum Inhibitory Concentration [MIC] and Inhibitory zone diameter were assessed by Microdilution broth and Disc diffusion agar techniques, MIC50, MIC90 and MFC were also determined. Minimum inhibitory concentration 90 [MIC90] essential oils of Thymus vulgaris, Petroselinum crispum, Cuminum cyminum and Bunium persicum were respectively 25, 72, 412, 130 micro g/ml and Minimal Fungicide Concentration [MFC] were 48, 146, 62, 280.Inhibitory zone diameters were 28, 20, 12, 15 millimetres. In this evaluation essential oils of Thymus vulgaris, Petroselinum crispum, Cuminum cyminum and Bunium persicum showed suitable antifungal effects against growth of standard strain of Candida albicans. Thus these herbal essences after supplementary studies possibly can be suitable substitute for chemical medicine on Candida infections especially on mucocutaneous Candidiasis

[Study of antibiotic susceptibility pattern and presence of ipaH gene among shigella strains isolated from selected provinces in Iran]

Shigellosis is one of the most common causes of morbidity and mortality in children with diarrhea in developing countries. It is essential to assess the antibiotic resistance patterns of these bacteria. ipaH gene is one of the virulence factors which can be used for detection of Shigella spp. Total of 100 isolates of Shigella were collected from different provinces of Iran. This isolates were characterized by biochemical tests and serological tests using polyclonal antisera for 4 species of S. dysenteriae, S. sonnei, S. boydii and S. flexneri. Antibiotic susceptibility assay for 14 different antibiotics was carried out using agar disc diffusion method. Presence of ipaH gene was investigated by PCR using specific primers. From the results of this study the Shigella isolates were classified as follows: 36 [%73] Shigella sonnei, 9 [%18] Shigella flexneri, 3 [%5] Shigella boydii, 2 [%4] Shigella dysenteriae. Approximately%50 of the Shigella isolates were resistant to Tetracycline and Cotrimoxazole. Shigella sonnei showed more resistance than other serotypes against the studied antibiotics. PCR assays showed that all isolates harbored ipaH gene. The results showed that prevalence of Shigella sonnei is higher than other serotypes. The isolates showed high sensitivity to third generation cephalosporines and aminoglycosides. PCR detection of ipaH gene as a reliable marker for identification of Shigella species could be recommended

[Investigation of protective effects of Pseudomonas aeruginosa antiflagellar antibodies in burned-induced infection on BALB/c mice]

Pseudomonas aeruginosa is the major cause of septicemia and wound infection in burned patients. Immunotraphy is the best practical way for prevention and treatment of these infections. Flagella as one of the most important bacterial virulence factors has important role in attachment, motility, chemotaxis and TLR-5-dependent immune response so that it propounded as a vaccine candidate. Production of anti-flagellar antibodies and evaluation of its protective effects in burned induced infection of mice was the main aim of this study. In the first step, flagellar antigen prepared by ultra-centrifugation. Antiflagellar antibodies produced in rabbit and its impurity separated by absorption technique. Specification of the obtained antibodies for flagellar antigen was investigated via agglutination test. After determination of LD50 in a known strain, different dilutions of anti-flagellar antibodies injected in burned mice for passive immunization. The rate of bacterial spread from burn site was determined by quantification assay of bacteria in skin and liver. In this study, clinical isolate and PA103 in addition to ATCC 27853 strain were used for agglutination test. H-antiserum reduced mortality of burned mice challenged with ATCC 27853 strains about 80%. Counting of bacteria in the skin and liver showed that the number of bacteria in immunized mice, in contrast with control group, was significantly low. The results of this study showed that anti-flagellar antibodies of Pseudomonas can inhibit invasion of Pseudomonas and facilitate its opsonization, so these antibodies have protective effects in burned wound infections

[Comparative study of cytotoxic effect of enterohemorrhagic escherichia coli verotoxin1 on vero and raji cell lines]

Verotoxin is a member of Shiga toxin family. This family contains AB protein toxins with an enzymatic [A] and a binding [B] compartment. Cells that have receptor [Gb3] are sensitive to cytotoxic effects of toxin. It has been shown that various tumor cells have Gb3 receptor and are selectively sensitive to apoptotic effect of verotoxin. Studies on tumor cell lines and laboratory animals have shown antineoplastic and antiangiogenesis effects of this toxin. The aim of this study was comparison of cytotoxic effect of verotoxin 1 on two cell lines: Vero [gold standard for evaluation of cytotoxic effect of Verotoxin] and Raji [a cell of a cultured line of lymphoblastoid cells derived from a Human Burkitt's lymphoma patients]. The toxigenic strain was cultured and the production of toxin was evaluated by reverse passive latex agglutination test. Verotoxin 1 was purified by affinity chromatography. Vero and Raji cell were treated with serial dilutions of toxin, and viability was evaluated by MTT test. Our result indicated that Verotoxin has cytotoxic effect on Raji cell lines. This effect is directly related to toxin concentration. Differences on cytotoxicity of toxin on Raji cells at 1:4-1:128 dilutions in relation to cytotoxicity of toxin on Vero cells at the same dilutions were considered statistically significant [P<0.05]. But difference of cytotoxicity of toxin at higher dilutions was not significant. Our results revealed that Verotoxin has cytotoxicity on Vero and Raji cells, and this effect on Vero cells is more than Raji cells [P<0.05]

[ molecular study of aac[3]-IIa [aacC2] gene in aminoglycoside resistant Escherichia coli isolated from urine]

Escherichia coli is the most prevalent etiologic agent of urinary tract infections which is the cause of about 80% of cases. Enzymatic inactivation of aminoglycosides by aminoglycosidemodifying enzymes is the main mechanism of resistance to these antibiotics in Escherichia coli. The aim of this study was the detection of aac [3] -IIa gene among aminoglycoside resistant clinical isolates of E. coli using PCR method. After collection of 250 clinical isolates of E. coli, antibiotic susceptibility patterns of isolates were determined by disk diffusion method for gentamicin, amikacin, tobramycin, kanamycin and netilmicin by considering the CLSI principles. Chromosomal and plasmid DNA of the isolates were extracted using DNA extraction Kits and PCR method was used for detection of the aac [3] -IIa gene. Results show that 96% of E. coli isolates were resistant to tobramycin, 90% resistant to kanamycin, 82% resistant to gentamicin, 30% resistant to netilmicin and 8% resistant to amikacin. aac [3] -IIa gene was detected in 54.83% of E. coli isolates. Because of high prevalence of resistance toward aminoglycoside antibiotics which is due to its transfer among bacteria by transferable elements such as transposons and plasmids. Therefor, tracing transfer routs among different bacteria is very important

[Isolation and identification of listeria monocytogenes in vaginal samples by PCR]

Listeria monocytogenes is a facultative, gram-positive bacterium which is found in soil, water, decaying vegetables, raw milk, and contaminated dairies. Listeria monocytogenes causes listeriosis. Listeriosis is a zoonosis disease, which transfers from animals to humans by animal feces and contaminated dairies. Listeriosis causes the flu like disease or self-limited enteritis, but it leads to serious disease in elderlies, new-borns, pregnant women and immunocompromised persons. If pregnant women are infected by Listeria monocytogenes, the newborn probably will be miscarried, prematured or stillborn. For the importance of the bacteria on pregnant women's and newborn's health, there are so much concentration and studies on it. Culturing of the bacteria is so difficult and time-consuming and it needs at least 5 days to confirm. Our goal in this survey was to develop an PCR based molecular method for fast detection of the bacteria from the vaginal samples. In this survey 100 vaginal samples were examined. All of the samples were cultured and assayed with PCR method. Among them, 7 samples for culture and 36 samples by PCR were positive for Listeria monocytogenes. In this study we showed that the PCR is a faster, more accurate and sensitive than culture method for the detection of Listeria monocytogenes in vaginal samples

[Prevalence of ant[4]-Ia gene among clinical isolates of methicillin-resistant Staphylococcus aureus using Multiplex-PCR method]

Methicillin-resistant Staphylococcus aureus is a major cause of nosocomial and community-acquired infections. Aminoglycosides are potent bactericidal agents that are often used in combination with either a beta -lactam or a glycopeptide, especially in the treatment of staphylococcal endocarditis. The main mechanism of aminoglycoside resistance in staphylococci is drug inactivation by cellular aminoglycoside-modifying enzymes. The main aim of the present study is determining the prevalence of ant[4]-Ia gene encoding one of the most important aminoglycoside-modifying enzymes and simultaneous detection of mecA gene responsible for methicillin resistance in clinical isolates of Staphylococcus aureus by Multiplex-PCR method. A total of 100 clinical S. aureus isolates were collected from Shariati and Baqiatollah hospitals in Tehran, then antibiotic susceptibility pattern of strains were determined by disk diffusion method using penicillin, oxacillin, vancomycin, tetracycline, erythromycin, gentamicin, tobramycin, amikacin, netilmicin and kanamycin disks, considering CLSI principles. Using agar dilution method the MIC for oxacillin, gentamicin, tobramycin and amikacin were also determined. In order to detect resistance genes, ant[4]-Ia and mecA, two pairs of specific primers were used and their prevalence was determined by using a Multiplex-PCR method. All strains were resistant to penicillin [100%] and after that the highest rate of resistance was observed against kanamycin [68%], tetracycline [61%], erythromycin [56%], tobramycin [53%], gentamicin [52%], amikacin and oxacillin [48%] and netilmicin [22%], respectively. All of the strains were also susceptible to vancomycin. In agar dilution method 50% of strains were oxacillin resistant and 49%, 45% and 51% of the strains showed resistance toward gentamicin, amikacin and tobramycin, respectively. Thirty-seven percent of the strains also showed high-level gentamicin resistance with MIC of >/= 128 micro g/ml. In Multiplex-PCR method 53% of the strains possessed mecA gene and 58% of the strains were ant[4?]-Ia positive. Results obtained by phenotypic and genotypic antibiotic susceptibility determination tests show that there is a statistically meaningful relationship between methicillin resistance and aminoglycoside resistance in MRSA strains [P<0.05]

Antifungal activity of essential oil and alcoholic extract of carum copticum against fluconazole-resistant and susceptible candida albicans isolated

Ajowan is an annual herbaceous essential oil of Carum copticom. The main components of the oil are Tymol, beta-pinene, gamma- terpinene and Sabinene. The fruit oil of Carum copticum has been reported to have several therapeutic effects including anti fungal, anti bacterial and anti viral, … Candida albicans is an opportunistic fungus and transforms into pathogenic form in favorable conditions, causing fungal diseases. In this study essential oil and alcoholic extract of Carum copticum were gained and Microdilution Broth method were used for detection of minimum inhibition concentration [MIC] and minimum fungicide concentration [MFC] of 11 clinical isolates of Candida albicans and Standard strain [PTCC50-27]. Results show that MIC for essential oil is 0.43 micro g/ml, 0.87 micro g/ml and for alcoholic extract is 3.51 micro g/ml, 7.03 micro g/ml, 1/75 micro g/ml. Thus, it seems that Carum copticum could inhibit Candida albicans growth by a similar mechanism which occurs by Fluconazole [FLZ]. In general, the results obtained in this study indicate that Carum copticum has potential values for growth inhibition of Candida albicans in vitro. In recent years, systemic fungal infections due to Candida species have been received major consideration about inducing mortality in nosocomial patients because of increasing in immunocompromised disorders such as AIDS and hematological disorders as well as long term use of broad spectrum antibiotics and corticosteroids. The present study was done with the aim of evaluating antifungal effects of essential oil and alcoholic extract from Carum copticum against Fluconazole [FLZ] susceptible and Fluconazole resistance Candida albicans strains isolated from different types of Candidiasis. Standard drug susceptibility tests with broth dilution technique were used to measure the in vitro antifungal activity of essential oil and alcoholic extract from Carum copticum. According to our results, it seems that Carum copticum could inhibit Candida albicans growth by a similar mechanism which occurs by FLZ and could be used as a potential antifungal agent especially with FLZ

[Morphologic changes of Mycobacterium tuberculosis after exposure with choloformic garlic extract]

Tuberculosis is one of the major problem facing of globle health. Drug resistance of mycobacterium tuberculosis to antimicrobial agent has strongly emerged the need for achiving the new drugs. Garlic as medical plants has long been taken under investigation. This study for antibacterial effect was done to determine the morphological alteration of Mycobacterium tuberculosis due to garlic choloformic extract. Garlic extract contains allicine [thio-2-propen-sulfonic acid-s-allil ester] is one of its effective antimicrobacterial substance. In a in-vitro study, the standard strain of Mycobacterium tuberculosis H37RV and clinical isolated strain was cultured in the middle broke 7H9 broth with different concentration of garlic extract in different 12, 24, 48, 72 hours. Morphological althertits of mycobacterium inspected with macroscopic and microscopic studies. The garlic exteract caused conversion of rough colonies to smooth and mucoid colonies and in microscopic studies morphologic change of mycobacterium from bacilli form to coccobacilli and cocci was observed. Also 0.67 mg/ml of garlic exteract on 48h period inhibited both of sensitive [standard strain of H37RV] and resistance [clinical strains] Mycobacterium tuberculosis. This study showed that garlic extract in addition to inhibiting growth, change the morphology of Mycobacterium tuberculosis from baccilli to cocoibaccill form and also alter the colony apearance from rough to smooth shap