Molecular characterization of gut microbial structure and diversity associated with colorectal cancer patients in Egypt.

Introduction: a large number of microbes colonizing the gut are highly diverse and complex in their structure, as this complex structure of gut microbiota acts as an indicator of a diseased state. Recently, there is a need for improved biomarkers for colorectal cancer (CRC) and advanced adenoma. Among the CRC associated organisms, bacteria are the most common causes of serious disease and deaths. To understand the dynamic interaction among bacteria colonizing the gut, different approaches have been implicated. Methods: in this study, faecal microbial markers were evaluated for detecting CRC. As most of these organisms are anaerobic, different molecular tools are of great values for rapid detection of these bacteria. Samples from Tumor Hospital were screened for the presence of different pathogens by both usual polymerase chain reaction (PCR) and a real-time assay. Results: in a total of 34 samples, by PCR method, bifidobacterium, fusobacterium and Escherichia coli (E. coli) were mainly identified in almost all samples. However, a clear variation in bacterial composition could be observed in Porphyromonas gingivalis, Prevotella intermedia and Peptostreptococcus magnus, where positive results could be detected only in diseased samples. In addition, E. faecium and E. saphenum were mainly identified in diseased samples. In contrast, providencia could be detected mainly in control samples. In realtime assay, the relative abundance was higher for fusobacterium and bifidobacterium markers in CRC patients compared to control samples. However, such increased in abundance has never been observed in both fusobacterium and bifidobacterium in the same sample. Conclusion: these results demonstrated increased abundance of fusobacterium or bifidobacterium can be considered as a sign for impairment or a diseased condition and the possibility of use of the faecal microbiotain CRC patients as a marker for detecting the disease.

Effects of Lysozyme, Proteinase K, and Cephalosporins on Biofilm Formation by Clinical Isolates of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an opportunistic pathogen that can form biofilms, which confer resistance to immune clearance and antibacterial treatment. Therefore, effective strategies to prevent biofilm formation are warranted. Here, 103 P. aeruginosa clinical isolates were quantitatively screened for biofilm formation ability via the tissue culture plate method. The effects of lysozyme (hydrolytic enzyme) and proteinase K (protease) on biofilm formation were evaluated at different concentrations. Lysozyme (30 µg/mL), but not proteinase K, significantly inhibited biofilm formation (19% inhibition). Treatment of 24-hour-old biofilms of P. aeruginosa isolates with 50 times the minimum inhibitory concentrations (MICs) of ceftazidime and cefepime significantly decreased the biofilm mass by 32.8% and 44%, respectively. Moreover, the exposure of 24-hour-old biofilms of P. aeruginosa isolates to lysozyme (30 µg/mL) and 50 times MICs of ceftazidime or cefepime resulted in a significant reduction in biofilm mass as compared with the exposure to lysozyme or either antibacterial agent alone. The best antibiofilm effect (49.3%) was observed with the combination of lysozyme (30 µg/mL) and 50 times MIC of cefepime. The promising antibiofilm activity observed after treatment with 50 times MIC of ceftazidime or cefepime alone or in combination with lysozyme (30 µg/mL) is indicative of a novel strategy to eradicate pseudomonal biofilms in intravascular devices and contact lenses.

Molecular detection of respiratory pathogens in isolates from two hospitals in Egypt using a microarray chip.

Respiratory tract infection is one of the most commonly spread communicable diseases. Among the causative organisms, bacteria are the most common causes of serious disease and deaths. A total of 32 samples were taken from Mansoura Lung Diseases Hospital and Kafr El-Sheikh General Diseases Hospital, in addition to 5 control samples were screened for the presence of different pathogens. In a total of 32 diseased samples, by PCR method, in Mansoura Lung Diseases Hospital, Hemophilus influenzae was detected in 2 samples, in addition to Klebsiella pneumoniae and Mycobacterium tuberculosis which were detected in 7 and 7 samples respectively. Mixed microbial infections were detected in 4 samples identified mainly as Klebsiella pneumoniae and Mycobacterium tuberculosis. However, in Kafr El-Sheikh General Diseases Hospital, Klebsiella Pneumoniae and Pseudomonas aeruginosa were detected in 8 and 8 isolates respectively. Mixed microbial infections were detected in 7 samples identified mainly as Klebsiella pneumoniae and Pseudomonas aeruginosa. DNA chip for pathogen detection indicated 100% matching with the test performed by PCR. Control samples were free from any pathogen. These results demonstrate variable results with respect to the geographical distribution and the possibility for fast identification of respiratory pathogens even in mixed culture in very short time.

The seroprevalence of parvovirus B19 antibody in blood donors at the National Blood Transfusion Center in Kinshasa.

BACKGROUND: Human parvovirus B19 (PVB19) is a cosmopolitan DNA virus transmissible parenterally by blood transfusion. Therefore, the risk of transmission through asymptomatic blood donors should be considered and appropriately managed worldwide. PVB19 screening of blood and blood products for transfusion is not done routinely in the Democratic Republic of Congo (DRC). The main objective of this study was to determine the seroprevalence of PVB19 infection in healthy eligible blood donors in Kinshasa, capital of the DRC, located in the western part of the DRC, and the association of infection with the sociodemographic characteristics of blood donors. MATERIALS AND METHODS: A total of 360 whole blood donors who attended the National Center of Blood Transfusion were examined for anti-PVB19 IgG and IgM antibodies by using enzyme-linked immunosorbent assay kits. Sociodemographic information was collected on the blood donors. All statistical analyses were performed with SPSS 21. RESULTS: Among the study group, 289 men and 52 women were infected with PVB19. The mean age was 32.7 ± 9.8 years, 48.6% of donors were positive only for PVB19 IgG antibodies while 40.8% were positive for both IgG and IgM antibodies. In addition, 5.3% were positive only for PVB19 IgM antibodies and so were considered as a potential group of PVB19 transfusion-transmission. PVB19 seropositivity was significantly associated with sex, with a higher prevalence in men. In multivariate analysis, male sex and Tshangu district have emerged as major factors associated to PVB19 seropositivity. CONCLUSIONS: This research showed that recipients of blood and blood products in Kinshasa are at a high risk (5.3%) of transfusion-transmitted PVB19 infection. Therefore, the implementation of PVB19 nucleic acid testing assays capable of detecting all PVB19 genotypes and discard donations with high titer PVB19 DNA for blood products seems to be necessary.