Early detection of oral bacteria causing gum infections and dental caries in children

Background and Objectives: Periodontal diseases are resulted from gum infections and dental plaques, which are mainly caused by the bacterial agents. Since dental monitoring includes important prognostic roles, the aim of this study was to detect the most common periodontal pathogenic bacteria in children. Materials and Methods: A total of 200 clinical samples were collected from dental plaques and gingival grooves. Target-specific primers were designed for hbpA in Aggregatibacter actinomycetemcomitans, fimA in Porphyromonas gingivalis and 16S rRNA in Prevotella intermedia, Tannerella forsythia and Treponema denticola. Then, a multiplex polymerase chain reaction method was optimized for the highlighted bacterial agents. Results: In general, the highest and the lowest bacterial prevalence rates belonged to Tannerella forsythia (88%) and Porphyromonas gingivalis (13%), respectively. Furthermore, prevalence rates of Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Treponema denticola were 25, 21 and 45% in samples, respectively. Conclusion: There were significant associations between dental/oral health and microbial community. Metabolism of the oral bacteria, including biofilm formation, can affect gums and develop dental plaques and hence dental caries, especially in children. Early diagnosis of dental caries in children via rapid, accurate molecular methods can increase the diagnostic capacity in clinical cases and therefore prevent periodontal infections in adulthood

Evaluation of the effect of Kandovan propolis against Streptococcus Mutans

BACKGROUND AND AIM: In recent years, propolis has been introduced as one the most efficient agents against cariogenic bacteria. However, due to the lack of data on the propolis collected from Kandovan (Easthern Azarbaijan, Iran), this study was designed to investigate the effect of this type of propolis on Streptococcus mutans (S. mutans). METHODS: In this experimental study, the ethanolic extraction of propolis (EEP) was prepared with different concentrations (1%, 3%, 5%, and 10%) while the distilled water was incorporated as control. The antibacterial efficacy was tested via two standard methods including the agar disk diffusion and minimum inhibitory concentration (MIC) tests. Finally, the resulting data were analyzed using one-way analysis of variance (ANOVA) and Bonferroni post-hoc tests ( = 0.05). RESULTS: The obtained MIC was 2.5 mg/ml. However, in disk diffusion test, the 1% and 3% EEP solutions did not exhibit any zone of inhibition, however the 5% EEP showed very strong antibacterial effect (P < 0.001). CONCLUSION: The EEP extracted from Kandovan had significant antibacterial effect against S. mutans when prepared in 5% concentration. Therefore, this type of propolis could be considered as one of the most efficient propolis against S. mutans. KEYWORDS: Propolis; Streptococcus Mutans; Antibacteria

Isolation and Purification of an Antibacterial Protein from Immune Induced Haemolymph of American Cockroach, Periplaneta americana

Background: Antimicrobial peptides play a role as effectors substances in the immunity of vertebrate and inverte­brate hosts. In the current study, antimicrobial peptide was isolated from the haemolymph of the American cock­roach, Periplaneta americana. Methods: Micrococcus luteus as Gram-positive bacteria and Escherichia coli as Gram-negative bacteria were candi­date for injection. Induction was done by injecting both bacteria into the abdominal cavity of two groups of cock­roaches separately. The haemolymphs were collected 24 hours after post injection and initially tested against both bacteria. Subsequently, the immune induced haemolymph was purified by high performance liquid chromatography (HPLC) to separate the proteins responsible for the antibacterial activity. Results: The non-induced haemolymph did not show any activity against both bacteria whereas induced haemo­lymph exhibited high activity against M. luteus but did less against E. coli. Two fractions showed antibacterial activ­ity against M. luteus. Finally the molecular weight of the isolated antibacterial proteins were determined as 72 kDa and 62 kDa using SDS-PAGE. Conclusion: Induced haemolymph of American cockroaches has the ability to produce peptides to combat against Gram-positive bacteria when an immune challenge is mounted. Further work has to be done to sequence of the pro­tein, which it would be advantageous

Evaluation of extended spectrum beta lactamase enzymes prevalence in clinical isolates of Escherichia coli

Resistance to b-lactam antibiotics by gramnegative bacteria, especially Escherichia coli (E. coli), is a major public health issue worldwide. The predominant resistance mechanism in gram negative bacteria particularly E. coli is via the production of extended spectrum beta lactamase (ESBLs) enzymes. In recent years, the prevalence of b-lactamase producing organisms is increased and identification of these isolates by using disk diffusion method and no-one else is not satisfactory. So, this investigation focused on evaluating the prevalence of ESBL enzymes by disk diffusion method and confirmatory test (Combined Disk). Five hundred clinical samples were collected and 200 E. coli isolates were detected by standard biochemical tests. To performing initial screening of ESBLs was used from Disk diffusion method on E. coli isolates. A confirmation test (Combined Disk method) was performed on isolates of resistant to cephalosporin's indicators. Up to 70% isolates exhibited the Multi Drug Resistance phenotype. In Disk diffusion method, 128(64%) E. coli isolates which resistant to ceftazidime and cefotaxime while in Combined Disk, among 128 screened isolates, 115 (89.8%) isolates were detected as ESBLs producers. This survey indicate beta lactamase enzymes are playing a significant role in antibiotic resistance and correct detection of them in phenotypic test by using disk diffusion and combined Disk is essential for accurate recognition of ESBLs

Invasion of HEp-2 cells by Shigella spp. isolated from acute pediatric diarrhea

Aim: infection is an important global health problem in developing countries where hygiene is poor and hence shigellosis is a main cause of diarrhoea-associated mortality and morbidity, particularly in children under the age of five. The bacterial entry into colon and rectal epithelial cells has been named ‘bacterium-directed phagocytosis’. This term highlights that the bacteria actively stimulate their own uptake into non-professional phagocytes. The aim of this study was to demonstrate the invasion of HEp-2 cells by spp. isolated from acute pediatric diarrhea in Tehran, Iran.Methods: Three-hundred and ten non-duplicative diarrheal stool samples were collected from the children admitted to Children’s Medical Center in Tehran, Iran. Samples were cultured and suspected colonies were identified by routine microbiological and biochemical tests. The invasion of the two isolated spp. to HEp-2 cells was studied.Results: Of 310 stool samples, 16 (5.2%) spp. were isolated, including seven (43.7%) and nine (56.3%) . Four (44.4%) and seven (42.8%) showed invasive phenotype to HEp-2.Conclusion: and are reported as the most prevalent spp. in nature which infect humans. Invasion of various cell lines gives the chance of survival to spp. This ability causes more virulent infections in the host. Despite costly and time consuming cell culture techniques, the current method described in this paper is reliable for detecting invasive behavior of spp. Results have also shown that not all the spp. are able to invade intestinal epithelial cells