Jundishapur Journal of Microbiology
Volume:2 Issue: 3, Jul-Sep 2009

Tuberculosis (TB) remains a worldwide healthcare concern and has been characterized as anepidemic by World Health Organization (WHO). In the last few decades, DNA fingerprinttechniques have become available to study the transmission of TB and other mycobacterialinfections. The main gold standard typing technique is restriction fragment lengthpolymorphism, which is widely used for molecular epidemiology purposes. However, otherrecently introduced techniques such as spoligotyping and MIRU-VNTR are also widelyused. This review briefly summarizes the recent achievements in TB epidemiologyassociated with the introduction of molecular typing methods for Mycobacteriumtuberculosis complex and non-M. tuberculosis complex mycobacteria. Besides, in thisarticle, the application of molecular methods in the study of epidemiological aspects anddiagnosis of mycobacterial diseases are highlighted.

Introduction and Pityriasis versicolor is a chronic superficial mycosis thatcaused by several species of Malassezia specially Malassezia globosa. The prevalence ofdisease is varying in the world with a rate of 5-50%. Disease is more prevalent in males thanfemales. The aim of the present study was to review the clinical and epidemiological profileof pityriasis versicolor in Ahvaz. Sellotape method was used for sampling from 500 subjectssuspected to pityriasis versicolor. The presence of clusters of yeasts, budding cells, andpseudophyae in methylene blue stained samples confirmed disease. In the present study, 30.6% of subjects were positive for pityriasis versicolor,62.1% were males, and 37.9% were females. Hypepigmentation lesions were common typeof disease followed by hypopigmentation and erythmatous type. In conclusion, 30.6% of studied population was positive for tinea versicolorwhich is a high prevalence for this disease.

Introduction and Proteus bacilli are opportunistic members ofEnterobacteriaceae and Proteus mirabilis is among the most common causes of communityor hospital acquired urinary tract infections (UTI) in many countries. In the present studyhemolysin production, salt tolerance and resistance to antibacterial agents in environmental and UTIs samples were compared. Bacteria were isolated from UTIs (n=80), chicken skin (n=34) andsoil (n=10). Resistance to 10 antimicrobial agents was determined by agar dilution method.In addition, β-lactamase and extended spectrum beta-lactamases (ESBLs) were alsodetermined by nitrocefin disks and double disk diffusion methods respectively. Totally, 62.9% of the isolates showed resistance to 8.5% sodium chloride, and thedifference in salt tolerance was significant in respect to species and origin of the samples.However, no significant difference in hemolysin production was detected in respect tospecies and origin of the samples. Resistance to trimethoprim-sulfamethoxazole (Sxt),amoxicillin (Amx) and chloramphenicol (C) were high (48.4% 41.9%, and 32.26%respectively), while sensitivity to β-lactams except amoxicillin was high (≥93.3%). β-lactamase production was found for 33% of the isolates and the MIC90 of Amx resistanceisolates was high, but reduced several folds in presence of clavulanic acids, however ESBLphenotype was not observed for any of the isolates. Hemolysin production was not significantly different in samples isolated fromdifferent sources, however isolates from soil were significantly more tolerance to salt(P=0.001). Resistance to some antibacterial agents was significantly higher in the isolatesfrom UTIs and chicken skins in comparison with the soil samples. This is important in thecase of Amx and Sxt, which are the important antibacterial agents for the treatment ofuncomplicated UTIs.

Introduction and Dental caries is a common oral bacterial pathology that hasbeen associated with Streptococcus spp., mainly Streptococcus mutans and Lactobacillusspp. Antibacterial activities of Terminalia chebula extracts against several bacterial strainshave been reported. The aim of this study was to evaluate the possible antimicrobialpotential of T. chebula fruit extracts (acetone, ethanol, methanol, cold and hot aqueous)against five dental caries causing microorganisms. For this purpose, three bacteria S. mutans, Staphylococcus aureus,Lactobacillus acidophilus and two yeasts Candida albicans and Saccharomyces cerevisiaewere tested. Antimicrobial activity was tested using agar well diffusion method. All thetested extracts showed antibacterial activity against two bacteria S. mutans and S. aureus butno antimicrobial activity was observed against L. acidophilus, C. albicans and S. cerevisiae. The highest activity was shown by the acetonic extract with a mean diameter ofinhibition zone being 25.32mm and a minimum inhibitory concentration (MIC) of 25mg/mlagainst S. mutans and a mean diameter of 32.97mm and a MIC of 12.5mg/ml against S.aureus followed by ethanolic, hot aqueous, cold aqueous and methanolic extracts. These promising findings suggest the presence of antibacterial activity in thetested plant material, exhibited by its bioactive compounds, and serving them as analternative antimicrobial agent against dental caries causing microorganisms.

Introduction and The appearance of resistance to anti-tuberculosis drugs hasgenerated research to find new and more effective drugs. Löwenstein-Jensen medium (LJ) isfrequently used for culturing strains of Mycobacterium tuberculosis. A group ofantimicrobial substances used in treating tuberculosis is sensitive to heat and cannot be usedon LJ medium. Research now aims to setup a modified method for evaluation of heat labiledrugs in LS medium. In this study, we investigated culturing M. tuberculosis for 48h onMiddlebrook 7H9 broth medium with antituberculosis drugs and re culturing on LJ medium(without antibiotic) and incubating for 40 days. Our results after 48h of contact of the strains with antibiotic were comparable withthe standard method of culture on Middlebrook 7H10 agar medium containing antibiotic.Therefore, 48h is a suitable time for primary contact between mycobacterium and heat labile antibiotics. This modified method can be applied to LJ medium instead of expensiveMiddlebrook 7H10 agar medium for evaluation of heat labile anti tuberculosis drugs.

Introduction and Approximately 1 in 3 women will require antimicrobialtreatment for a Urinary Tract Infection (UTI) before age 24, and 40% to 50% of women willhave a UTI during their lifetime. UTIs in male patients are considered complicated.Escherichia coli is the most common cause of UTIs. In the present study 7056 patients with clinical symptoms andsuspected to UTI were sampled. Clean-Catch midstream urine of the patients was collected.Urine specimens were cultured for isolation of the microbial agents of UTI. The isolatedbacteria were identified using biochemical tests. Disk diffusion susceptibility test was usedto determine susceptibility of bacterial agents to antibiotics. In this study 553(8.7%) patients out of 7056 were shown to be urine culturepositive (68% females and 32% males). The most isolated bacterium was E. coli withfrequency rate of 59%. The other bacteria were Klebsiella spp. (11.6%), Enterobacter spp.(9.8%), Pseudomonas spp. (7.2 %), Proteus spp. (2.9%), Acinetobacter spp. (2.7%),Congolese positive Staphylococci (2.2%), Coagolase negative Staphylococci (2.3%),Citrobacter spp. (1.3%) and Streptococci α hemolytic (1.1%). All Gram-negative bacteriawere more sensitive to amikacin (90.5-100%). The Gram-positive cocci isolated were moresensitive to tobramycin, kanamycin and ciprofloxacin (100%). It is concluded that Gram-negative bacilli were responsible for UTI infectionsin our patients. The most common isolated bacteria from urinary tract infections were E. coliand the most effective antimicrobial agents were amikacin, tobramicin and ciprofleoxacinagainst Gram-negative bacilli and also the most effective antibiotics against Gram-positivecocci were kanamicin, tobramicin and ciprofleoxacin.