Molecular characterization of environmental non-Tuberculous mycobacteria using PCR- RFLP analysis of 441 Bp heat shock protein 65 fragments

Non- Tuberculous Mycobacteria are environmental opportunistic pathogens that can be found in various terrestrial and aquatic habitats. There are an epidemiological links between species isolated in tap water and those isolated from patients. hsp65 gene has more variability in its sequences, compared to the some more conserved genes in NTM, for identification of mycobacteria to species level. In this study, the prevalence of NTM in Isfahan City water samples was determined using culture, biochemical tests and PCR-RFLP analyses of hsp65 gene. Eighty-five water samples were collected and cultured. The mycobacterial isolates were identified by conventional biochemical tests. A 441 bp fragment of hsp65 genes was amplified and digested by two restriction enzymes, BstEII and HaeII. Digested products were analyzed using polyacrilamid gel electrophoresis [PAGE]. 25.9% of the water samples contained different species of NTM. Dominant isolates were M. fortuitum [26.7%], M. chelonae like organism [13.3%] and M. mucogenicum [13.3%]. Nineteen isolates of Mycobacteria were differentiated using hsp65 genes PCR-RFLP. Three isolates could not be identified at the species level because their RFLP patterns were different from other known PCR-RFLP profiles. There were different hsp65 gene PCR-RFLP profiles produced by digestion with BstEII and HaeIII. This study showed that PCR-RFLP of hsp65 gene in mycobacteria is more reliable method for identification of NTM at the specie level than conventional phenotypic methods [P<0.05]. In comparing of RFLP patterns of this study to other investigation, some minor differences were negligible

[Molecular study of per and veb genes is multidrug resistant pseudomonas aeroginosa isolated from clinical specimens in Isfahan/Iran and their antibiotic resistance patterns]

Duo to clinical use of antibiotics, pseudomonas aeruginosa strains with multiple drugs resistance have significantly increased throughout the world. Betalactamase production is one of the Mechanisms involved in resistance to pseudomonas aeruginosa resulting in many problems in the treatment of infections caused by this bacterium. The aim of this study was molecular analysis of PER and VEB genes in Pseudomonas with multiple resistance isolated from clinical samples in Isfahan/Iran. In whole, 98 isolates of Pseudomonas aeruginosa from various clinical specimens were identified by biochemical tests and the antibiotic susceptibility of the identified strains were determined using Kirby-Bauer method. PCR was performed on the samples to evaluate the presence or absence of PER and VEB genes. Among 98 strains of Pseudomonas aeruginosa, 73 samples [73%] were multiple drugs resistant and all of them were cefotaxime, cefepime and ceftazidime resistant. Prevalence of PER and VEB genes were respectively 5 [6.84%] and 8 [10.9%]. Considering high prevalence of multi-drug resistant Pseudomonas aeroginosa, it is essential to reduce these pathogens in hospitals through controlling PER and VEB genes transfer

[ inhibitory effect of lactobacillus rhamnosus GG on vancomycin resistant enterococcus faecalis colonization in mouse]

Vancomycin Resistant Enterococci [VRE] are among the most common nosocomial pathogens worldwide. The intestinal tract provides a major source for transmission of these bacteria. Probiotics are living microorganisms that moderate use of them has inhibitory effect on intestinal colonization by enteric pathogens. We examined the effect of Lactobacillus rhamnosus GG [LGG] on inhibition of VRE colonization in mouse model. Twenty four mice [Balb/C] were controlled for a week and then were infected to VRE by daily receiving of 1ml oral vancomycin [250 micro g/ml] and 1ml VRE suspension in MHB [5x10[8]CFU/ml] for one week. Mice were randomly divided into two groups of treatment and control, and the effect of LGG probiotic was compared in the tow groups. VRE, total Enterococci, and enteric gram-negative bacilli counts in feces were determined before and after colonization by VRE. At first, all mice were colonized by non -Vancomycin Resistant Enterococci [mean 5x10[5]CFU/g for 7 days], and Vancomycin resistance was not detectable. Following gastric inoculation of VRE and receiving oral vancomycin, VRE was colonized in gastrointestinal tract of all mice [mean 1.6x10[6]CFU/g for 7 days]. Oral administration of LGG suppressed growth of all Enterococci, including the vancomycin-resistant strain in treatment group feces [P<0. 05]. It is concluded that probiotic can reduce colonization of VRE. More studies on the effect of probiotics in prevention and treatment of VRE and other common pathogens are suggested