Probiotics: an update on mechanisms of action and clinical applications

Probiotics are live microbial feed supplement and can provide health benefit to the host if administered in sufficient amounts. The most predominant species that have been used as probiotic include Lactobacilli and bifidobacteria. Proper administration of probiotics could be efficient in the treatment of various disorders. However; their mechanism of action is poorly understood. The effects of probiotics may be classified in following modes: reinforcement of the intestinal mucosal barrier against pathogens, competition with pathogens for adherence to the mucosa and epithelium, competitive exclusion of pathogenic microorganisms, production of antimicrobial substances, modulation of the immune system and interference with quorum sensing signaling. Exploration of the clinical features of probiotic strains, their modes of action and investigation based on probiotic therapy may be beneficial in treatment of various diseases

Investigating Effects of Clay and Carbonaceous Nanoparticles on Asphalt Degradation Aerobic Microorganisms

Background: Hot mix asphalt (HMA) is one of the most important structures to implement the road and street surfaces, which always exposed to destruction. Provide new solutions to reduce the destructive process of effective factors on asphalt destruction and increasing prolong of its lifetime is important for society of road engineers. Traffic loading and weather conditions are the major factors that have role on different asphalt destruction.Materials and Methods: In this study, three types of HMAs, which contain nanoclay, and carbon nanotubes were produced by Marshall method in Iran University of Science and Technology, and one type of aged HMA were also collected for further investigations. The HMA samples were transferred to microbiology laboratory of Shahid Beheshti University of Medical Sciences, and then suspensions were prepared from specimens and cultured on nutrient agar medium. After 24 hours’ incubation at 37 ̊C the bacteria that were grown on the plate were identified. At least the effect of clay and carbon nanoparticles on minimum inhibitory concentration (MIC) of bacteria, were determined by microdilution broth method.Results: A lot of bacterial colonies (Bacillus and Pseudomonas) were collected from the aged specimens. The asphalt, which contain nanoclay had more bacteria than the nanocarbon asphalt. The carbon and clay nanoparticles in 2% and 4% concentration prevented the growth of bacteria, respectively.Conclusion: The old asphalt had more bacteria than other samples, which shows bacteria are one of the main factors in decomposition of asphalt by applying corrosion to bituminous hydrocarbons. Presence of clay and carbon nanoparticles in asphalt structures could increase the durability of the HMAs and reduce the relevant economics costs

Assessment of antibiotic resistance pattern in Acinetobacter bumannii carrying bla oxA type genes isolated from hospitalized patients

AbstractPlease cite this article as: Goudarzi H, Douraghi M, Ghalavand Z, Goudarzi M. Assessment of antibiotic resistance pattern in Acinetobacter baumannii carrying bla oxA type genes isolated from hospitalized patients. Novel Biomed 2013;1(2):54-61.Introduction: Acinetobacter baumannii is a Gram-negative coccobacillus and one of the most opportunistic pathogens responsible for serious infections in hospitalized patients.Methods: During a 12 month study, 221 clinical isolates and 22 environmental Acinetobacter baumannii isolates were collected. In vitro susceptibility of Acinetobacter baumannii isolates to 13 antimicrobial agents amikacin; cefepime; ceftazidime; ciprofloxacin; meropenem; piperacillin/tazobactam; sulfamethoxazole/ trimethoprim; imipenem; tigecycline; colistin; gentamycin; ceftriaxone; levofloxacin was performed by the disk diffusion method and Minimum Inhibitory Concentration(MICs) of imipenem; levofloxacin and cefepime.was done by the E-test according to Clinical and Laboratory Standards Institute (CLSI) criteria. blaOXA-23, blaOXA-24, blaOXA-58, blaOXA-51genes were detected by polymerase chain reaction and sequencing.Results: The result of antimicrobial susceptibility test of clinical isolates by the disk diffusion method revealed that that all strains of Acinetobacter baumannii were resistant to piperacillin/tazobactam. The rates of resistance to the majority of antibiotics tested varied between 69% and 100 %, with the exception of tigecycline and colistin. Of 221 isolates tested 99(44.8%) were XDR. All strains carry a blaOXA-51-like gene. blaOXA-23gene was the most prevalence among blaOXA-types.Conclusion: colistin and tigecycline can be effective drugs for treatment of Acinetobacter baumannii infections. Continuous Surveillance for Acinetobacter baumannii multidrug-resistant strains is necessary to prevent the further spread of resistant isolates

Distribution of Enterotoxigenic Escherichia coli among E. coli isolates from diarrheal samples referred to educational hospitals in Tehran-Iran

Background: Introduction: Enterotoxigenic Escherichia coli (ETEC) is the most important bacterial cause of watery  travelers' diarrhea  in  developing countries. Watery diarrhea is can cause serious life-threatening dehydration. ETEC was caused diarrhea by the secretion of two heat-labile enterotoxins (LTs) and the heat-stable enterotoxins (STs) which increase intestinal secretion. Routine laboratory methods are not appropriate to detect ETEC and other diarrheagenic E. coli pathotypes. The molecular techniques such as PCR are rapid and accurate methods that have been developed for detection of ETEC. We were recognized ETEC by PCR on lt and st genes from E. coli isolates from patients with diarrhea collected from selected Tehran educational hospitals.Materials and Methods: The E. coli isolates were collected from total 140 patients with diarrhea and 110 patients without diarrhea using culture and IMViC test. DNA was extracted by boiling method and the presence of the uidA, lt and st genes was detected by PCR.Results: Among 140 E. coli isolates from diarrheal stools 5 (3.6%) isolates were positive for, just lt gene, 3 (2.1%) co-amplified for both lt/st and 1 (0.7%) was positive for just the st gene which were considered as ETEC. In the E. coli isolates from non-diarrheal control samples just one (0.9%) isolate was positive for both lt and st genes.Conclusion: The results showed that the ETEC as a significant cause of diarrhea, usually ignored by laboratories using traditional methods. Sometimes the ETEC causes severe diarrhea and can threaten for patient's life. Thus a rapid diagnostic test such as PCR can be very helpful in the treatment of patients

Antimicrobial Effect of Methanolic and Acetonic of Zataria Multiflora, Capsicum Annum L. and Piper Nigrum L. Extracts on Pseudomonas aeruginosa Strains Isolated from Patients Hospitalized in the Burn Ward of Shahid Motahari Hospital in Tehran

 Background: Pseudomonas aeruginosa (P. aeruginosa) is one of the main causes of nosocomial infection. Burn patients are at high risk of acquiring this bacterium due to skin damage and their immune deficiency, and mortality rate in these infected patients is high (40-50%). Therefore, due to antibiotic resistance of MBL containing strains in this bacterium, the aim of this study is to investigate the effect of methanol and acetone of Zataria multiflora, Capsicum annum L. and Piper nigrum L. on strains containing MBL in this bacterium.Materials and Methods: This lab study was conducted on samples from burn patients, which were gathered between 2015 and 2016. In this study first, disc diffusion and MIC were done based on the CLSI protocol; and using a combined disk, we detected metallo-beta-lactamase. Next, the bla (IMP) and bla (VIM) genes were identified by the PCR method. In order to investigate the effect of three plants extract on bacteria, the bacteria was affected by triple extracts using MIC and disk diffusion.Results: According to the results, all three plants had an acceptable effect on Pseudomonas aeruginosa strains containing metallo-beta-lactamase, and to be more precise, the acetone type of extract of Capsicum Annum L at a concentration of 1.5 mg / ml had the best effect in treating of these bacteria.Conclusion: The results of this study indicate the presence of several mechanisms of resistance to beta-lactam antibiotics among Pseudomonas aeruginosa strains collected from burn patients. The emergence of these types of XDRs has led to health problems, especially in burn patients. According to the results, the methanolic and acetonic extract of all three plants have been shown to be effective in inhibiting the growth of MBL-containing Pseudomonas aeruginosa

Determination of antibiotic resistance in clinical isolates of coagulase negative Staphylococci from hospitalized patients in selected hospitals of Tehran

To investigate the prevalence of methicillin and aminoglycoside resistance and gene encoding staphylococcal cassette chromosome mec (SCCmec) and aminoglycoside modifying enzymes in clinical isolates of coagulase negative staphylococci(CoNS) from hospitalized patients. One hundred and three isolates of coagulase negative staphylococci(CoNS) were recovered from various clinical samples from August 2013 to November 2014. All the specimens were identified by conventional microbiological methods. These tests were contained colony morphology, gram stain, catalase, slide and tube coagulase. To determine the sensibility of CoNS to antimicrobial components including Cefoxitin(30µg), Tobramycin(10µg), Kanamycin(30µg), Amikacin(30µg) and Gentamicin(10µg), disk diffusion method was performed by Kirby Bauer antibiotic testing. In order to show the presence of  methicillin and aminoglycoside resistant CoNS genes, PCR were demonstrated. In our study the rate of resistance to Cefoxitin, Kanamycin, Gentamicin, Tobramycin and Amikacin were 74(71.8%), 54(52,4%), 51(49.5%), 45(43.7%) and 16(15.5%), respectively. Some strains of CoNS have been detected with intermediate resistance to Kanamycin 4(3.9%), Tobramycin and Amikacin 2(1.9%). In our study, the distribution of mecA gene among clinical isolates of CoNS was 89(86.4%). The prevalence of aminoglycoside resistance genes like ant(4 ')-Ia, aac(6 ')/aph(2 ") and aph(3 ')-IIIa were 89(86.4%), 87(84.5%) and 68(66%), respectively. The rate of coexistence of aac(6’)-Ie-aph(2’’) with aph(3’)-IIIa and aac(6’)-Ie-aph(2’’) with ant(4’)-Ia was 65(63%) and 77(74%), respectively. Resistance to aminoglycosides, develops quickly in coagulase-negative staphylococci from clinical areas where these antimicrobial agents are widely used. Therefore, higher investments should be directed towards identifying coagulase-negative staphylococcus species in healthcare institutions and in the community. Overall, Knowing the epidemiology and antibiotic resistance of CoNS is essential to implement the prevention strategies and reducing antibiotic consumptions

Bacteria Isolated from Urinary Tract Infection among Patients and Determination of the Antibiotic Susceptibility Patterns of the Gram Negative Bacteria in Iran

Background: Escherichia coli (E. coli) is the most frequent infecting organism in acute infection. So, knowledge about the frequency and distribution of urinary tract infection (UTI) is important to improve infection control measures. The aim of this research was to determine the prevalence of bacteria isolated from urinary tract infection (UTI) in patients and determination of the antibiotic susceptibility patterns of the gram negative bacteria.Materials and Methods: This descriptive study was performed in Imam Reza hospital, Tabriz (northwest of Iran) during March 2012 to February 2013. We surveyed 8153 patients, who had clinical manifestations of UTI. 5093 (62.47%) of them were female and 3060 (37.53%) of them male. Urine specimens were cultured for isolation of the microbial agents of UTI. The isolated bacteria were identified using biochemical tests. Disk diffusion susceptibility test was used to determine antimicrobial susceptibility.Results: E. coli (55.38%) was the most common isolated pathogen, followed by Enterobacter spp. (29.61%), Pseudomonas spp. (4.9%), S. aureus (3.21%), Enterococcus spp. (2.3%),  fungi (1.5%) and Klebsiella (0.48%). The sensitivity rates of isolated gram negative bacteria were for Amikacin (95.7%), Nitrofurantoin (91.5%), Gentamicin (64.1%), Ceftizoxim (56.8%), Ciprofloxacin (37.6%), Cotrimoxazole (31.4%) and Nalidixic acid (23.5%).Conclusion: This study showed that the frequency of E. coli and  Enterobacter spp. increases the probability of urinary tract infection. Also this survey indicates the emergence of antibiotic resistant infections in the studied hospital. So, there is a need to improve the effectiveness of integrated infection control programs to control and manage nosocomial infections caused by highly resistant organisms

The antibacterial activity of Iranian plants extracts against metallo beta-lactamase producing Pseudomonas aeruginosa strains

Metallo β-lactamases (MBLs) producing Pseudomonas aeruginosa (P. aeruginosa) isolates are becoming an escalating global threat. Among the antibiotics used to treat infections associated with P. aeruginosa, resistance to carbapenem is a serious therapeutic challenge. The aim of the present study was to detect MBL-producing P. aeruginosa and to evaluate the extracts of Urtica. dioica, Carum. copticum, and Zataria multiflora on these clinical pathogens. The study was performed on hospitalized burn patients during 2014. Antibiotic susceptibility testing was tested by broth micro dilution and disc diffusion methods. The MBLs were detected using combination disk diffusion test (CDDT) phenotypically. Then, PCR and sequencing methods were carried out to detect the MBL encoding genes. Among 83 imipenem resistant P. aeruginosa strains, 48 (57.9%) isolates were MBL-producing P. aeruginosa. PCR and sequencing methods confirmed that these strains were blaIMP-1positive genes, whereas none were positive for blaVIM genes. Hospitalized burn patients with MBL-producing P.aeruginosa infection had 4/48 (8.3%) mortality rate. It was demonstrated that C. copticum, U. dioica, and Z. multiflora extracts had significant antibacterial effects on regular and IMP-producing P. aeruginosa strains. The prevalence of MBL-producing P .aeruginosa isolates in burn patients is very high. In this study, all MBL-producing strains encode the blaIMP-1gene. Therefore, detection of MBL-producing strains has major importance in identifying drug resistance patterns in P. aeruginosa and in controlling of infections. In the current study, the extracts from C. copticum, U. dioica, and Z. multiflora had high antibacterial effects against β-lactamase producing P. aeruginosa isolates.