Study of intestinal microbial flora of local chickens to investigate the effect of probiotics Bacillus subtilis and Bacillus coagulans on the expression of ctxM and luxS pathogenic genes in isolates of Escherichia coli

Background and objective: Antibiotics are widely used worldwide. However, due to the emergence of antibiotic resistance in a wide range of microorganisms, their use worldwide has failed. Probiotics are suggested as complementary and alternative medicine. The present study aimed to investigate the effects of probiotics isolated from local chickens on the expression of luxS and ctxM genes in resistant Escherichia coli.

Materials and methods: 300 fecal samples were taken from patients referring to Imam Khomeini Hospital in Tehran during May–September 2016 and Escherichia coli samples were isolated using specific culture media and biochemical tests and then the presence of luxS and ctxM genes were identified using PCR with specific primers. In order to extract the probiotics forming spores, the intestinal contents of 10 poultry that had not used any antibiotics and probiotics were cultured, isolated, and identified using biochemical and PCR methods. Commercial strains of Bacillus subtilis and Bacillus coagulans were purchased to compare their effects with native bacteria. These strains were then co-cultured with resistant Escherichia coli strains containing ctxM and luxS genes. Real-time PCR was used to evaluate the effect of these probiotics on gene expression

Results: The results indicated that 40 isolates (7.5%) of Escherichia coli were obtained from the 300 fecal samples. Thirteen samples (32.5%) were outpatients and 27 (67.5%) were inpatients. All isolates were isolated from men and women aged 21–62. Four Escherichia coli strains were isolated from patients carrying ctxM and luxS genes. Isolation of Bacillus coagulans and Bacillus subtilis from samples was confirmed by biochemical and molecular experiments. The commercial and native strains of Bacillus coagulans reduced the expression of the luxS and ctxM genes by 3.60, 3.30, 1.58, and 2.70 times respectively. Also, the commercial and native strains of Bacillus subtilis decreased the expression of the luxS and ctxM genes by 1.37, 1.10, 2.20, and 2.80 times respectively. The results of statistical analysis showed a significant relationship between the presence of native and commercial probiotics in culture and reduced expression of ctxM and luxS genes.

Conclusion: According to the results, supplements of Bacillus coagulans and Bacillus subtilis increase the effect of antibiotics resistance in Escherichia coli by reducing the expression of resistance genes.

Assessment of biofilm formation in Pseudomonas aeruginosa by antisense mazE-PNA

The hallmark patogenicity in Pseudomonas aeruginosa (P. aeruginosa) is biofilm formation that is not easy to eradicate, because it has variety mechanisms for antibiotic resistance. In addition, toxin-antitoxin (TA) system may play role in biofilm formation. The current study aimed to evaluate the role of TA loci in biofilm formation. Therefore, 18 P. aeruginosa clinical isolates were collected and evaluated for specific biofilm and TA genes. The analysis by RT-qPCR demonstrated that expression of mazE antitoxin in biofilm formation was increase. On the other hand, mazE antitoxin TA system was used as target for antisense PNA. mazE-PNA was able to influence in biofilm formation and was inhibit at 5,10 and 15 μM concentrations biofilm formation in P. aeruginosa. Therefore, it could be highlighted target for anti-biofilm target to eradicate P. aeruginosa biofilm producer.

Noncoding Control Region Pattern of BK polyomavirus in Kidney Transplant Patients With Nephropathy

OBJECTIVES

Adaptation of BK polyomavirus with infected host cells may cause rearrangement of the noncoding control region of viral genomic DNA. Archetype, the prearranged transmissible form of the virus, actively replicates in the tubular epithelial cells, whereas isolates with rearranged noncoding control region sequences are found in other parts of the kidney. Clinical observations highlighted the importance of the noncoding control region rearrangements in BK virus-associated nephropathy. Therefore, we evaluated the sequence pattern of the noncoding control region in kidney transplant patients suspected of having BK virus-associated nephropathy.

MATERIALS AND METHODS

In this single-center, cross-sectional study, 129 kidney transplant patients suspected of having BK virus-associated nephropathy and who were admitted to Namazi Hospital were enrolled for analysis between years 2010 and 2013. Blood samples were collected from each patient. The BK polyomavirus infection was diagnosed using quantitative real-time polymerase chain reaction. The BK polyomavirus-infected patient plasma samples were amplified using in-house nested polymerase chain reaction and sequenced. The contiguous alignment noncoding control region sequences were analyzed with software.

RESULTS

The BK polyomavirus infection was observed in plasma samples of 11 of 129 (8.5%) patients after kidney transplant. Sequence alignments showed that BK polyomavirus noncoding control region sequences in all viral infected patients with BK virus-associated nephropathy showed a complete rearranged algorithm compared with the archetype sequences. The most prevalent noncoding control region sequences were registered in a genetic sequence database (National Institutes of Health). No association was observed between risk factors and BK polyomavirus infection. There were 3 BK polyomavirus-infected patients who simultaneously had active cytomegalovirus infection.

CONCLUSIONS

Determination of the rearranged pattern of the noncoding control region sequences in BK polyomavirus isolates from plasma samples may help improve the diagnostic and therapeutic protocols against this viral infection in patients with BK virus-associated nephropathy.

Plasmid mediated antibiotic resistance in isolated bacteria from burned patients

BACKGROUND

Nowadays, the treatment of burned patients is difficult because of the high frequency of infection with antibiotic resistance bacteria.

OBJECTIVES

This study was conducted to evaluate the level of antibiotic resistance in Gram-negative bacteria and its relation with the existence of plasmid.

MATERIALS AND METHODS

The samples were collected from two hundred twenty hospitalized burned patients in Isfahan burn hospital during a three-month period (March 2012 to June 2012). The samples were isolated and the Gram-negative bacteria were identified using phenotypic method and API 20E System. Antibiotic susceptibility and plasmid profile were determined by standard Agar disc diffusion and plasmid spin column extraction methods.

RESULTS

Totally 117 Gram-negative bacteria were isolated, the most common were Pseudomonas aerugionsa (37.6%), P. fluorescens (25.6%), Acinetobacter baumanii (20/5%) and Klebsiella pneumoniae (7.6%), respectively. The isolates showed high frequency of antibiotic resistance against ceftazidime and co-amoxiclave (100%) and low frequency of antibiotic resistance against amikacin with (70%).The results indicated that 60% of the isolates harboured plasmid. On the other hand, the patients infected with A. baumanii and P. aeruginosa were cured (with 60% frequency) whereas, those infected with P. fluorescens were not cured. Hence, probably antibiotic resistance markers of A. baumanii and P. aeruginosa are plasmid mediated; however, P. fluorescens is chromosomally mediated.

CONCLUSIONS

Based on our findings, P. aerugionsa is a major causative agent of wound infections and amikacin could be considered as a more effective antibiotic for treatment of the burned patients.