ABSTRACT
Aim: This study evaluated the frequency of C. difficile and CDAD in the ICU of Shahid Bahonhar Hospital, Kerman, Iran
Background: Clostridium difficile [C. difficile] is the most important antibiotic associated diarrhea agent in intensive care unit [ICU] patients. Based on its toxin producing ability, C .difficile is divided to toxigenic and non-toxigenic strains
Methods: A total of 233 diarrheal samples were collected from ICU patients. The samples were cultured on Clostridium difficile medium with 5% defibrinated sheep blood containing cycloserine [500 mg/L], cefoxitin [16 mg/L] and lysozyme [5mg/L]. The isolates were confirmed as C. difficile by polymerase chain reaction [PCR] of 16s rRNA gene and the presence of toxins genes [tcdA, tcdB, cdtA and cdtB] was also confirmed. Then, the toxin production of isolates was evaluated using ELISA
Results: C. difficile was isolated from 49 [21%] out of 233 samples. The total isolates fell into the A-/B-/CDT- [48.97%], A+/B- /CDT- [28%], A+/B+/CDT- [20.4%] and A+/B+/CDT+ [2%] types. Both types of C.difficile, A-/B-/CDT- and A+/B-/CDT-, which account for 77.5% of all isolates, were unable to produce the toxin [nontoxigenic]. On the other hand, A+/B+/CDT+ and A+/B+/CDT- [22.5%], were able to produce toxin or were toxigenic
Conclusion: The frequency of C. difficile was about 21% and only 22.4% of C. difficile isolates were able to produce toxins. It is expected that C. difficile A+/B+/CDT+- are toxigenic and related to C. difficile associated diarrhea [CDAD]. Additionally, about 4.7% of hospitalized patients in ICU suffered from CDAD, which is higher than the rates reported from industrialized countries. Notably, 28% of isolates were C. difficile A+/B-/CDT- which only carries tcdA genes without toxin production
ABSTRACT
BACKGROUND: Enterococcus faecalis is an opportunistic pathogen that causes most of the enterococcal infections. Among the different factors implicated in the pathogenesis of these organisms, biofilm formation and antibiotic resistance are the most important. The ability for biofilm formation has been attributed to the presence of some virulence genes. However, no definite correlation has been found. This study aimed to detect biofilm formation and antibiotic resistance patterns in E. faecalis isolates collected from clinical and fecal samples, and to investigate possible correlation between some virulence genes (esp, cyl, gelE) and biofilm formation. MATERIALS AND METHODS: A collection of 123 E. faecalis isolates were investigated for antibiotic resistance and production of hemolysin, gelatinase, and biofilm using phenotypic methods. The esp, gelE and cyl genes were detected using polymerase chain reaction. RESULTS: Thirty-eight pathogenic isolates (37%) were positive for biofilm formation. Additionally, the gelE, esp, and cyl genes were detected in 74 (71.8%), 79 (76.7%) and 42 (40.8%) isolates, respectively. In the fecal samples, 18 (90%) isolates were biofilm producers and 11 (55%), 17 (85%) and 8 (40%) isolates were positive for gelE, esp, and cyl, respectively. There were significant differences in biofilm production between pathogenic and fecal isolates (P <0.001). Multidrug resistance (MDR) was found among 32% (n = 33) and 15% (n = 3) of the clinical and fecal isolates, respectively. However, no significant difference was seen between MDR and biofilm formation. Five pathogenic and two fecal isolates were negative for all investigated genes while they were they were biofilm producers. In contrast, 22 pathogenic isolates and 1 fecal isolate were positive for the tested genes, but did not form any biofilm. No significant differences were observed between biofilm formation and the presence of the esp, gelE and cyl genes in the pathogenic and fecal isolates (P ˃0.05). CONCLUSION: The presence of the esp, gelE and cyl genes might not be determining factors for biofilm formation in enterococci and other mechanisms might be involved in this process.
Subject(s)
Biofilms , Drug Resistance, Microbial , Drug Resistance, Multiple , Enterococcus faecalis , Enterococcus , Gelatinases , Polymerase Chain Reaction , VirulenceABSTRACT
Aim: This study aims to determine the serogroup distribution and molecular diagnosis, as well as antimicrobial resistance profiles among Shigella spp. isolated from patients with diarrhea in Kerman, southeast of Iran
Background: Shigella species are frequent cause of bacterial dysentery worldwide. Previous studies have been reported that S. sonnei and S. flexneri are the most prevalent serogroups in various parts of Iran
Patients and Methods: A total of 624 stool samples were randomly collected from patients with diarrhea from June 2013 to August 2014. Biochemical and serological characterizations were performed for identifying Shigella spp. In addition, the multiplex PCR assay was carried out for the detection and differentiation of three pathogenic Shigella spp. Antibiotic susceptibility testing was performed according to the Clinical Laboratory Standards Institute [CLSI] guidelines
Results: Fifty six [9%] Shigella strains were isolated from stool samples. The most common species were S. flexneri 31[55.4%], followed by S. sonnei 18[32.1%] and S. boydii 7[12.5%]. S. dysentery was not detected in the present study. All the isolates that identified by serological test as Shigella spp. were confirmed by the multiplex PCR method. The highest rate of resistance was observed for ampicillin and trimethoprim-sulphamethoxazole antibiotics with 52[92.9%] resistant, followed by tetracycline 44[78.6%] and cefotaxime 33[58.9%]. All Shigella isolates were susceptible to ciprofloxacin. A significant relationship was found between the Shigella species and cefotaxime resistance [p<0.05]
Conclusion: S. flexneri was found as the most prevalent serogroup causing shigellosis. The high rate of resistance to third-generation cephalosporins limits the treatment options available for the management of shigellosis in Kerman, Iran
ABSTRACT
Background: Antibiotic resistant bacteria can be considered as a main problem in infection management. Zinc oxide nanoparticles [ZnO NPs], individually or in combination with antibiotics, can be considered as good candidates for struggling against drug resistant bacteria
Methods: In this study, Zinc oxide nanoparticles were synthesized using sol-gel method in low temperature as a cost effective procedure and characterized by X-ray diffraction and Scanning Electron Microscopy. Antibacterial activity of 9 new combinations of Zinc oxide nanoparticles and ceftazidime was assessed against standards and new clinically isolated multi drug resistant Pseudomonas aeruginosa [P. aeruginosa], in order to evaluate enhancement effect of synthesized Zinc oxide nanoparticles on antibacterial activity of ceftazidime
Results: The results indicated that desirable effects can be seen at 6 and 7 mM of Zinc oxide nanoparticles [60 to 100% inhibition]. Moreover, after evaluation of 9 new combinations with various concentrations of both components, it was demonstrated that Zinc oxide nanoparticles can enhance the antibacterial activity of ceftazidime, against some bacterial strains of P. aeruginosa. The highest activity was observed with the concentration of 20 micro g/ml ceftazidime in the presence of 5, 6 or 7 mM of Zinc oxide nanoparticles
Conclusion: Zinc oxide nanoparticles in appropriate concentrations can be proposed as new and promising candidates for overcoming bacterial resistance
ABSTRACT
Aims: Pseudomonas aeruginosa is a drug resistance opportunistic bacterium. Biofilm formation is key factor for survival of P. aeruginosa in various environments. Polysaccharides may be involved in biofilm formation. The purpose of this study was to evaluate antimicrobial and anti-biofilm activities of seven plant extracts with known alpha-glucosidase inhibitory activities on different strains of P. aeruginosa. Methodology and results: Plants were extracted with methanol by the maceration method. Antimicrobial activities were determined by agar dilution and by growth yield as measured by OD560nm of the Luria Bertani broth (LB) culture with or without extracts. In agar dilution method, extracts of Quercus infectoria inhibited the growth of all, while Myrtus communis extract inhibited the growth of 3 out of 8 bacterial strains with minimum inhibitory concentration (MIC) of 1000 μg/mL. All extracts significantly (p≤0.003) reduced growth rate of the bacteria in comparison with the control without extracts in LB broth at sub-MIC concentrations (500 μg/mL). All plant extracts significantly (p≤0.003) reduced biofilm formation compared to the controls. Glycyrrhiza glabra and Q. infectoria had the highest anti-biofilm activities. No correlation between the alpha-glucosidase inhibitory activity with growth or the intensity of biofilm formation was found. Conclusion, significance and impact of study: Extracts of Q. infectoria and M. communis had the most antimicrobial, while Q. infectoria and G. glabra had the highest anti-biofilm activities. All plant extracts had anti-biofilm activities with marginal effect on growth, suggesting that the mechanisms of these activities are unrelated to static or cidal effects. Further work to understand the relation between antimicrobial and biofilm formation is needed for development of new means to fight the infectious caused by this bacterium in future.
ABSTRACT
Non-fermenting Gram-negative bacteria are unable to ferment sugars in order to generate energy. They are ubiquitous in nature, and have a wide geographic distribution. They are also common in hospital settings, and may be isolated from humidifiers, ventilator machines, dialysis machines and other equipment, as well as from the skin of hospital personnel. This study focused on the isolation of multidrug resistant [MDR] non-fermenting Gram negative bacteria from clinical samples. Antimicrobial susceptibility, detection of extended spectrum beta-lactamases [ESBL], and the presence of CTX-M and Metallo beta-lactamase [MBL] in the isolated bacteria were evaluated. Agar dilution method was used to test the susceptibility of the isolates to 10 antibacterial agents. All the isolates that were resistant to >/= 3 antibacterial agents from different classes were regarded as MDR [111 isolates] and were selected for further studies. beta-lactamase and ESBL production were detected by nitrocefin discs, combined discs [CD] and double discs plus CD [DCDT]. blaCTX-M and MBL were detected by PCR and EDTA synergy methods respectively. Among the MDR isolates the isolation frequency of Pseudomonas aeruoginosa, Stenotrophomonas maltophilia and Acinetoacter baumannii were 83.7%, 9.9% and 6.3% respectively. Resistance to imipenem [0.9%] and Ceftazidim [13.6%] was low, but resistance to other beta-lactams was high, and 29.7% were resistant to >/= 6 antibacterial agents from different classes simultaneously. beta-lactamase was produced by 41.4% of the MDR isolates. Detection of ESBLs by a CD [59.4%] or DCDT test [46.8%] was not significantly different, but with a combination of CD and DCDT a higher percentage of ESBLs in the isolates [P
ABSTRACT
The use of mouth rinses as antiseptics to prepare surgical site is highly recommended by surgical principles and they are used even after doing surgery. Chlorhexidine has been considered as an effective antibacterial mouth rinse but as its well known side effects are potentially harmful, Persica mouth rinse which is supposed to be as effective as Chlorhexidine with less side effects, due to its herbal origin, was compared with Chlorhexidine mouthrinse. The aim of this study was to compare the antibacterial and cytotoxic effects of Chlorhexidine and Persica mouthrinses. In this in vitro experimental study Streptococcus Mutans, Streptococcus Sanguis and Lactobacillus Kasei were exposed to Persica [absolute and 50%] and Chlorhexidine concentrations [0.01% ,0.02% ,0.1% ,0.2%] for 2 ,10 , 30 minutes. The growth of microorganisms were evaluated after 24hr incubation. The human oral carcinoma cell line KB, the human osteosarcoma cell line Saos-2 , the mouse macrophage cell line J774A.1 and human gingival fibroblast cell line MRF were exposed to Persica [0.1% , 0.5% , 1% , 5%] and Chlorhexidine concentrations [0.0001%, 0.001%, 0.01%, 0.03%] for 1 hr. Following drug exposure the cells were washed and cultured for another 48-72 hrs, then, cell growth was assessed by MTT assay. All concentrations of Chlorhexidine prevented the growth of microorganisms but Persica mouthwash had a weak antibacterial effect. Chlorohexidine concentrations of higher than 0.001% had significant cytotoxicity in all cell lines and concentrations of higher than 0.1% of Persica also exerted a very significant cytotoxic effect on all cell lines. Persica mouth rinse is not a reliable antiseptic for preparation of oral cavity prior to oral surgery since it doesn't bear enough antibacterial properties. Both mouth rinses are cytotoxic, so that, using them for wound care, specially for oral wounds which heal by secondary intention is not recommended
ABSTRACT
The use of plants in treatment of burns, dermatophytes, and infectious diseases is common in traditional medicine of Iran. Based on ethno pharmacological and taxonomic information, antibacterial activities of methanol extracts of some medicinal plants of Iran were determined by In Vitro bioassays using agar diffusion-method against standard strains of Pseudomonas aeruginosa, P. fluorescens, Bacillus subtilis, B. cereus and B. pumilis at 20 mg/ml. From 180 plant species of 72 families, 78 species [43.3%] in 42 families [58.3%] showed antibacterial activities against B. cereus [88.4%], B. subtilis [39.7%], B. pumilis [37.1%], P. fluorescens [37.1%] and P. aeruginos [10.2%]. The most active plant families were Apiaceae, Compositae and Labiatae with 9, 8 and 7 active plant species respectively. Minimum inhibitory concentrations [MIC] of the active plants were determined using two fold serial dilutions. Most active plant against Bacilli was Myrtus communis L. with MIC of 1.87 mg/ml. For Pseudomonas species, Dianthus caryophyllus L. and Terminalia chebula [Gaertner] Retz. were more active with the MIC of 0.46 mg/ml for P. fluorescens and of 1.87 mg/ml for P. aeruginosa respectively