RESUMEN
Quorum sensing [QS] plays a very important role in virulence and biofilm formation of Pseudomonas aeruginosa. We tested the effect of the aqueous garlic extract [AGE] on QS regulated biofilm formation and on antimicrobial susceptibility profile of P. aeruginosa isolates. One hundred P. aeruginosa isolates from patients with nosocomial infections from different departments of Sohag University Hospitals were collected during the period from April 2016 to April 2017. These isolates were tested for antibiotic sensitivity by the disc diffusion method and were screened phenotypically for biofilm formation by the Congo Red Agar [CRA] method and Tissue Culture Plate [TCP] technique. The presence of LasI, LasR, Rh1I and Rh1R genes in biofilm forming P. aeruginosa isolates was tested by using polymerase chain reaction [PCR]. Biofilm producing strains were investigated by exposure to sub-inhibitory concentration of AGE as a quorum-sensing inhibitory agent. P. aeruginosa showed the highest antibiotic resistance rate to Piperacillin [85%], followed by Ticarcillin-Clavulanate [84%], while the highest sensitivity was to Colistin [73%], followed by Polymyxin B [64%], and lastly to Meropenem [56%]. Eighty % of the isolated samples were biofilm producers, and most of these were from ICU patients.Strains were found to have different distribution of individual QS genes. LasI gene was present in 74% of isolates, LasR gene was present in 58% of isolates, Rh1I gene was present in 43% of isolates and Rh1R gene was present in 36% of isolates. On exposure of biofilm producing strains to the AGE there was significant improvement of the antibiotic sensitivity profile and significant decrease of biofilm formation. This work highlighted the bioactivity of garlic extract, as a Quorum Sensing inhibitory agent, in effectively inhibiting biofilm formation and increasing the sensitivity of the pathogens to antibiotics
RESUMEN
Introduction: infection with Helicobacter pylori is accepted as a main cause of gastritis and gastritis associated diseases. Giardia lamblia parasite is considered the most common protozoal infection in human. Concomitant H. pylori and Giardia infection is common for their similar mode of transmission and strong correlation to socioeconomic levels, but only few reports had described gastric giardiasis. In this work, H. pylori and Giardia lamblia were detected by PCR in gastric antral mucosal biopsies from a random sample of patients complaining from dyspepsia, in Sohag University Hospital, Egypt. Results were compared with a control group of patients undergoing EGD for other reasons rather than dyspepsia. The impact of H. pylori and Giardia lamblia infection whether singularly or concert, on clinical, endoscopic or histopathogical changes was studied
Patients and methods: 48 patients [26 males and 22 females] with dyspepsia and 28 control [26 males and 2 females], were subjected to esophagogastroduodenoscopy [EGD]. Endoscopic data were reported and gastric biopsy specimens were obtained for subsequent PCR assay for H. pylori and Giardia lamblia, histopathological and electron microscopic examination
Results: endoscopic antral gastritis and duodenal lesions were found in both patients and controls. Both lesions occurred significantly more frequently in patients group [p= 0.002 and 0.0005 respectively]. Esophageal lesions, nodular antral gastritis, gastric ulcers and superficial carpal gastritis were found only in patients group. PCR detected H. pylori infection in 28 out of the 48 patients [about 58%] and in 18 out of 28 [64%] control subjects while Giardia lamblia infection was present in 32 out of 48 patients [67%] compared to 12 out of 28 controls [64%]. In the latter, the results were statistically significant [P=0.0003, Odd ratio=2.6]. Co-infection with H. pylori and Giardia was present in 33% of patients compared to 36% of controls. Abnormal histologic findings were found in both patients and control groups, however, gastric atrophy occurred significantly more frequently in symptomatizing patients [P=0.027] with an odd ratio = 2.6. Intestinal metaplasia was found only in the patients group. Electron microscopic study; cellular abnormalities in the form of cytoplasmic vacuoles, mitochondrial destruction or nuclear abnormalities were found in infected subjects [H.pylori, Giardia or both]
Conclusion: H. pylori is not the only gastric pathogen in our community, gastric giardiasis is quite common. Its contribution to symptoms or pathological changes couldn't be confirmed in our study but it might be a factor in persistent epigastric pain after H. pylori eradication