International Journal of Enteric Pathogens
Year:2017 | Volume:5 | Issue:3|Papers Count:7

The microbiota is an ecological community of commensal, symbiotic, and pathogenic microorganisms. The gut microbiota has evolved as a new important player in the pathophysiology of many intestinal diseases. Recently, special interest has been arisen on gut microbiota-host interaction because extensive evidence has shown that intestinal microbiota composition has an important role in human health and disease such as infectious diseases. Dysbiosis of the microbiota has been related to a plethora of infections and still increasing number of diseases. Studies have mostly focused on analyzing the associations between disease and an aberrant microbiota composition.

Background: Food-borne intoxications are current problems in human society and most of them are caused by the enterotoxins of Staphylococcus aureus. Staphylococcal enterotoxin A (SEA) is the most frequently responsible for staphylococcal food poisoning outbreaks. From a food safety and human health point of view, lactic acid bacteria (LAB) may provide a promising strategy to combat the pathogenic bacteria, particularly S. aureus.Objective: The objective of this study was to evaluate the inhibitory activity of two commercial lactobacillus strains on growth and enterotoxin A production by S. aureus. Moreover, the inhibitory effect of these strains on gene expression of enterotoxin type A was assessed using real-time Polymerase chain reaction (PCR).Materials and Methods: In this study the inhibitory effect of two commercial probiotic strains, Lactobacillus acidophilus (LA5) and Lactobacillus casei 01 on the growth and enterotoxin production of S. aureus was evaluated at 25 and 35°C. The gene expression of SEA of S. aureus was also evaluated by real time (RT) PCR technique.Results: The lactobacillus strains decreased the bacterial count at both temperatures compared with the control group. This reduced effect was greater at 25°C (3 log/CFU) than 35oC (2 log/CFU). The production of SEA, SEC and SEE was inhibited by the lactobacillus strains. Furthermore, the gene expression of SEA was significantly suppressed in S. aureus co cultured with studied lactobacillus strains and the greatest down-regulation of sea (10.31 fold) was observed in co-incubation of S. aureus with LC01 at 25oC.Conclusion: This research raises important implications for the potential use of LAB as a natural preservative in foodstuffs by correct microbial ecology of the environment and a new approach for biocontrol of S. aureus.

Background: Staphylococcus aureus is one of the most important pathogens and the cause of suppuration, abscess formation, a variety of pyogenic infections, and even fatal septicemia in human beings. Isolation of resistant strains of S. aureus especially meticillin-resistant one has elucidated the importance of finding new antibacterial agents. Sumac is one of the important medicinal herbs of Iranian traditional medicine (ITM). Sumac has been traditionally prescribed for some ailments with infectious etiology and therefore, it probably contains antibacterial compounds. Recently, antibacterial activities of sumac against some bacteria were studied by our team.Objective: In this article, we aimed to compare the antibacterial activities of sumac against meticillin susceptible (MSSA) and meticillin resistant S. aureus (MRSA) via minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) determination.Materials and Methods: Antibacterial activity of sumac water extract was studied on 19 clinical and 1 standard strain of S. aureus via MIC and MBC determination. Based on their sensitivity to cloxacillin, these bacteria were classified as meticillin-susceptible, intermediate meticillin-resistant, and meticillin-resistant. MICs and MBCs of the extracts in these 3 groups were statistically compared via one-way analysis of variance (ANOVA) followed by a post hoc analysis (Tukey HSD test) using SPSS for Windows (version 15).Results: The results showed that in spite of different susceptibilities to cloxacillin, susceptibility to sumac extract was not different and MICs and MBCs of sumac for all clinical isolates including MSSA and MRSA were similar (P>0.05).Conclusion: Based on previous studies, sumac extract acts against S. aureus probably through changing the cell wall properties. This activity is similar for both MRSA and MSSA. More investigation on the precise mechanism of action of this extract would be fruitful.

Background: Assessment of changes in structure and activity of catalase, as an antioxidant enzymatic protein, in combination with glucose and essential unsaturated fatty acids is the aim of present study.Materials and Methods: In order to investigate the activity and structure of catalase, a solution of this enzyme with 10 mg/mL concentration in phosphate buffer (0.1 M) and pH=7.4, in the presence and absence of 50 mmol glucose was prepared, filtered, and then incubated for 4 months at 37°C with and without fatty acids including linolenic, linoleic, and arachidonic acids, separately. Samples were taken from each tube of solution, every 14 days for 4 months, to assess the fluorescence emission, circular dichroism (CD) and activity.Results: According to the results, catalase showed increase in fluorescence emission and decrease in activity after incubation with glucose in comparison with pure protein. Moreover, catalase showed alteration in CD after incubation with glucose during 4 months. After incubation with glucose and each of the mentioned unsaturated fatty acids, alterations of catalase were neared toward normal level in fluorescence emission, CD, and activity in comparison with pure protein.Conclusion: Functional and structural protection of catalase against damages from hyperglycemic environment with addition of essential unsaturated fatty acids was proved in our investigation.

Background: Multidrug resistant bacteria continue to be a bane in the treatment of clinical infections in Nigeria. Knowledge of trends in resistance mechanisms is vital in determining available therapeutic options.Objective: This study was aimed at determining the prevalence, distribution and antimicrobial susceptibility of extended spectrum b-lactamase (ESBL), AmpC b-lactamase and metallo-b-lactamase (MBL) -producing gram negative bacteria (GNB) recovered from clinical specimens in a tertiary hospital in Southern Nigeria.Materials and Methods: A total of 309 consecutive non-repetitive clinical bacterial isolates were recovered from various clinical specimens. The presence of ESBL, AmpC b-lactamase and MBL as well as the susceptibility profiles were determined using standard microbiological techniques.Results: ESBL was the most prevalent (P<0.0001) of the 3 enzymes detected in this study. Bacterial isolates recovered from inpatients had a higher likelihood of producing ESBL than those recovered from out-patients (odds ratio [OR] =2.225, 95% CI=1.375, 3.599; P=0.0015). The highest prevalence of ESBL, AmpC and MBL enzyme was observed for Providencia species, Pseudomonas aeruginosa and Citrobacter species respectively. b-Lactamase positive isolates showed poor activity against cephalosporin, amoxicillin-clavulanate, gentamicin and the fluoroquinolones. Isolates that produced any of the three b-lactamase enzymes showed more resistance to antibacterial drugs than b-lactamase negative bacterial isolates.Conclusion: A prevalence of 41.7%, 15.2% and 28.5% was observed for ESBL, AmpC b-lactamase and MBL respectively in this study. Isolates that produced any of the enzymes were more resistant to antibacterial agents. Prudence in antibiotic use is strongly advocated.

Background: Microbial infections such as shigellosis are one of the major health challenges in Iran, especially in Khuzestan province in the south west of Iran.Objective: According to the importance of medicinal plants in the treatment of many infectious diseases, and as a valuable alternative for antibiotics, the aim of this research was to assess the antibacterial and drug synergistic activities of the essential oil from Mentha longifolia, a local plant, against Shigella flexneri and Shigella sonnei as the main causes of shigellosis.Materials and Methods: The M. longifolia essential oil was extracted from the leaves. The antibacterial activities of the essential oil against clinical and standard S. flexneri and S. sonnei strains were detected by the disk diffusion and micro-broth dilution methods.Results: The essential oil of M. longifolia had the most significant antibacterial activity against the clinical strain of S. flexneri. Minimum inhibitory concentration (MIC) of 1024 with a concentration of 0.8 mg/mL of essential oil was detected in both the standard and clinical S. flexneri and S. sonnei strains. The essential oil of M. longifolia showed the highest synergistic effect on gentamicin and ampicillin in the clinical isolates of S. flexneri.Conclusion: The results of this study showed that the essential oil of M. longifolia alone or in combination with antimicrobial agents may be useful in the treatment of bacterial infections. In addition, M. longifolia may increase the effect of antibiotics and resolve other antibiotic resistance problems.

Infection of clavicle is a rare complication in children that is difficult to diagnose. The exact incidence is unknown. We report a case of osteomyelitis of the clavicle without any long term disability.