Diagnostic medical microbiology

• Bacterial Exotoxins• Comparison of Bacterial Exotoxins with Endotoxin• Summary of Host-Parasite Interactions• Pathogen Virulenc

Vancomycin Resistant Enterococci (VRE) among Non–Hospitalized Individuals in Gaza City, Palestine

Objectives: This study was conducted to investigate the occurrence of VRE among non–hospitalized individuals and to evaluate the public awareness of the globally escalating issue of antibiotics resistance. Methods: One hundred non-hospitalized individuals were interviewed and stool sample was collected from each during the period between January and June, 2006. Isolation of Enterococci was performed according to standard method. Each Enterococcus isolate was subjected to vancomycin susceptibility test. Results were statistically analyzed using SPSS software Results: We obtained 84 enterococcal isolates out of one hundred stool sample, 32.1% of them were resistant to vancomycin. No significant difference between male and female, level of education, hospitalization, age and Enterococcus carriage or VRE. Higher percentage of VRE was observed among those who were previously admitted to hospitals. Conclusions: A high percentage of Vancomycin resistance was demonstrated among Enterococcus spp. isolated from non-hospitalized individuals. No single risk factor could be attributed to acquiring VRE. Therefore, we may conclude that the general population is equally exposed

Focused molecular analysis of small cell lung cancer: feasibility in routine clinical practice

© 2015 Abdelraouf et al.Background: There is an urgent need to identify molecular signatures in small cell lung cancer (SCLC) that may select patients who are likely to respond to molecularly targeted therapies. In this study, we investigate the feasibility of undertaking focused molecular analyses on routine diagnostic biopsies in patients with SCLC. Methods: A series of histopathologically confirmed formalin-fixed, paraffin-embedded SCLC specimens were analysed for epidermal growth factor receptors (EGFR), KRAS, NRAS and BRAF mutations, ALK gene rearrangements and MET amplification. EGFR and KRAS mutation testing was evaluated using real time polymerase chain reaction (RT-PCR cobas®), BRAF and NRAS mutations using multiplex PCR and capillary electrophoresis-single strand conformation analysis, and ALK and MET aberrations with fluorescent in situ hybridization. All genetic aberrations detected were validated independently. Results: A total of 105 patients diagnosed with SCLC between July 1990 and September 2006 were included. 60 (57 %) patients had suitable tumour tissue for molecular testing. 25 patients were successfully evaluated for all six pre-defined molecular aberrations. Eleven patients failed all molecular analysis. No mutations in EGFR, KRAS and NRAS were detected, and no ALK gene rearrangements or MET gene amplifications were identified. A V600E substitution in BRAF was detected in a Caucasian male smoker diagnosed with SCLC with squamoid and glandular features. Conclusion: The paucity of patients with sufficient tumour tissue, quality of DNA extracted and low frequency of aberrations detected indicate that alternative molecular characterisation approaches are necessary, such as the use of circulating plasma DNA in patients with SCLC

Multidrug Resistance of Uropathogens at Governmental Hospitals in the Gaza Strip/Palestine

Urinary tract infection is a public health problem worldwide. E. coli and klebsiella are among the main etiologic for UTI in Gaza Strip. The growing variations in resistance among uropathogens to antimicrobials is multifactorial and varies globally. It greatly reduces/limits or complicate treatment option. Aims: To determine the pattern of antimicrobial resistance and multidrug resistance among uropathogens at governmental hospitals. Methods: We analyzed the data of 11,890 urine samples processed in governmental hospitals in the Gaza Strip, Palestine during 2019. The percentage of resistance was calculated for uropathogens, and then multidrug resistance was calculated according to “CDC†definition. Results: Of 11,890 urine samples, 2910 (24.5%) showed significant growth.  Escherichia coli was isolated most frequently (1743; 59.9%), followed by Klebsiella spp. (725; 24.9%), Pseudomonas spp. (123; 4.2%), Streptococcus spp. (98; 3.4%), Staphylococcus aureus (41; 1.4%). Microorganisms resistance was high against Ampicillin (92.4%) and Amoxicillin (91.1%), Co-Trimoxazole (68.2%), Cefalexin (64.9%), Doxycycline (61.9%), Nalidixic acid (53.6%), Cefuroxime (53.0%), Ceftriaxone (48.9%), Ceftazidime (43.1%), Ciprofloxacin (36.9%), Gentamicin (25.8%), Amikacin (3.2%). The resistance of microorganisms in males is higher than females. Multidrug resistance was detected in 37% of E. coli and 53% in Klebsiella spp. Conclusion: Resistance is high and variable among uropathogens isolated from patients in Gaza strip. Both age and gender are risk factors in both infection and resistance pattern. The multidrug resistance percentage is growing remarkably in Gaza Strip. Keywords: Uropathogens, Resistance, Urinary tract infection, Multidrug resistance, Gaza strip, Palestine &nbsp

Antibacterial, antifungal and synergistic effect of Lawsonia inermis, Punica granatum and Hibiscus sabdariffa

The increased prevalence of antibiotic resistance, as a result of extensive antibiotic use, may render the current antimicrobial agents insufficient to control, at least, some bacterial infections. The concept of this research is based on the Sunnah of Prophet Mohammad “peace be upon him” of using Henna as a medication for wounds. The aim of this study is to investigate the antimicrobial and antifungal activity of Lawsonia inermis, Punica granatum, and Hibiscus sabdariffa and to examine the synergistic effect of mixing plant extracts with antibiotic. By extraction 30g of grounded plant extract with 500ml from the solvent by soxhlet apparatus (soaked the grounded plant in solvent 72h). The antibacterial and antifungal activities were investigated by using sensitivity test on Mueller Hinton agar and Potato Dextrose agar, respectively. The methanolic extract of Punica granatum showed the highest antibacterial activity especially against Staphylococcus aureus, while, Klebsiella pneumonia and Escherichia coli showed the least sensitivity to the same extract. Association of antibiotics and plant extract showed synergistic antibacterial activity especially with Ciprofloxacin and Erythromycin on Pseudomonas aeruginosa, and Staphylococcus aureus, respectively. The activity of Ketoconazole and Fluconazole drugs was highly increased after mixing with the aqueous extract of Hibiscus sabdariffa. The Nystatin antifungal showed higher activity when mixed with plant extract. In conclusion, all tested plants extracts showed potential antimicrobial activity against the tested pathogens. The synergistic effect against fungi was more clear and higher from the effect

A Threatened Introduced Species (<em>Ficus benghalensis</em> L.) in Ismailia, Egypt

The genus Ficus belongs to Moraceae (Mulberry family). It is comprised of around 1000 species from pantropica land subtropical origins; plants of the family are on the whole woody, ranging from trees and shrubs to climbers. F. benghalensis has many common names as Indian banyan tree, East Indian fig tree, and vada tree, banyan tree is considered sacred by Hindus and is largely grown near temples. It is a large and extensive growing tree of the Indian subcontinent. Ficus compound showed significant antioxidant effect, which might be ascribed to their polyphenolic nature. The stem bark of Ficus benghalensis L. and Ficus racemosa L. are utilized in India for the treatment of diabetes and various different illnesses. The bark of Ficus benghalensis decreased fasting blood sugar and glycosylated hemoglobin. The fruit of Ficus benghalensis is used in folk medicine for respiratory disorders and certain skin disease

Antimicrobial Resistance and Biofilm Formation of Pseudomonas aeruginosa: A short review article

Pseudomonas aeruginosa threatens patient’s care. It is considered as the most complicated health care associated pathogen to be eliminated from infection site. The biofilm forming ability of&nbsp;P. aeruginosa, being a major virulence factor for most pathogenic microorganism, protects it from host immunity and contribute to antibiotic resistance of this organism. It is estimated that about 80% of infectious diseases are due to biofilm mode of growth. Biofilm forming ability of bacteria imparts antimicrobial resistance that leads to many persistent and chronic bacterial infections. The world is becoming increasingly under the threat of entering the “post-antibiotic eraâ€, an era in which the rate of death from bacterial infections is higher than from cancer. This review focus on P. aeruginosa biofilm forming ability; definition, developmental stages, and significance. In addition, the quorum sensing and the antibiotic resistance of this pathogen is discussed. Keywords: Biofilm; bacterial adhesion; Pseudomonas aeruginosa; antimicrobial resistance; quorum sensing. &nbsp

Synthesis of Nanometal Oxide–Coated Cotton Composites

Several selected studies dealing with the development of novel antimicrobial metal oxide–coated cotton nanocomposites and their antimicrobial applications have been reviewed in this chapter. Synthesis of metal oxide nanoparticles (NPs) and its deposition onto cotton fibers were conducted using various methods. These include the high energy γ-radiation, thermal treatment-assisted impregnation, “pad-dry-cure” of the impregnated fabric in the colloid formulation of metal oxide soluble, and ultrasonic radiation methods. The coated metal oxide nanoparticles have shown an effective enhancement for antimicrobial activity. They reduce the chance of diseases originating from hospital infections. The antimicrobial properties of cotton fabrics finished with metal oxide NPs against a variety of bacterial strains commonly associated with nosocomial infections, caused by Staphylococcus aureus and Escherichia coli, have been investigated by four different methods. The morphology of the cotton-coated metal oxide nanoparticles and their chemical structure have been analyzed by UV-vis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS). SEM and XRD analyses revealed that the shape and size of the coated nanoparticles are dependent on the nature of the metal oxide and its preparation conditions

Antimicrobial Resistance of Enteric Pathogens Isolated from Acute Gastroenteritis Patients in Gaza strip, Palestine

Background: Acute gastroenteritis is a severe infection of the gastrointestinal tract (GI). The antibiotic resistance of enteric bacteria has profound clinical implications because it threats the life and worsens the acute gastroenteritis disease. This study is a matched case-control study and aims to determine enteropathogenic bacteria, their antibiotic resistance and associated-risk factors in diarrheal patients in Gaza Strip.   Methods: 132 patients with acute diarrhea were investigated. In addition, data were collected from 132 healthy controls having the same characteristics of patients except the fact they didn’t suffer from diarrhea within the last three months. The age categories of patients are &lt; 5 and &gt; 5 years old. Data were collected through completing a questionnaire form for cases and controls and stool samples were collected from six Primary Health Care Clinics and these samples were inoculated on selective media in Remal clinic- Microbiology laboratory. Results: 12 (9.1%) enteropathogenic bacteria were isolated from 132 stool samples. Salmonella, Campylobacter coli/jejuni, and Aeromonas hydrophilia were isolated in equal numbers from samples 3/12 (25% each), Shigella 2/12 (16.7%), and Yersinia enterocolytica 1/12 (8.3%). The two Shigella spp. are Shigella boydii. The antimicrobial profile of all isolated enteropathogenic bacteria showed high resistance rates for the tested antimicrobials (C. coli/jejuni (52.4%), followed by A. hydrophilia (49.2%), Y. enterocolytica (42.9%), Shigella (26.2%) and Salmonella spp. (22.2%). In addition the antimicrobial profile of the isolated enteropathogenic bacteria showed high resistance rate to rifampin (91.6%), clindamycin (83.3%), erythromycin (75%), cephalexin and tetracycline (66.6%).  Conclusions: The isolated enteropathogenic bacteria showed high resistance rate to several antimicrobials. This study isolated C. coli/jejuni, A. hydrophilia, and Y. enterocolytica, which are not screened for during routine examinations of stool samples in Palestinian health laboratories in Gaza Strip.  Recommendations: We recommend improving of laboratory services in Gaza Strip to extend their ability to isolate all types of enteropathogenic bacteria especially those, which are not isolated routinely. Â

Biofilm Formation and Methicillin Resistance of Staphylococcus aureus Isolated from Clinical Samples

Background: Staphylococcus aureus&nbsp;including methicillin resistant&nbsp;S. aureus&nbsp;(MRSA) is one of the most effective biofilm-forming organisms, biofilm contribute in protecting the microorganism from host defenses and prevent the effective penetration of antimicrobial agents. Biofilm formation is considered as an important contributing factor for the initiation and establishment of chronic infection by S. aureus and known as a major obstacle in the treatment of S. aureus infections is their ability to develop resistance to antimicrobials. Aims : To screen clinical Staphylococcus aureus including MRSA isolates for their biofilm forming abilities and their association with antimicrobial resistance. Methods: A total of 196 clinical isolates of&nbsp;S. aureus&nbsp;were obtained from different sample sources using standard microbiological techniques from three major hospitals in Gaza strip. Biofilm formation of these isolates was determined by tissue culture plate (TCP) method and tube adherence method (TM). Antimicrobial susceptibility test was performed using the modified Kirby–Bauer disk diffusion method as per Clinical and Laboratory Standards Institute guidelines. MRSA was detected using the cefoxitin disk test. Results: Biofilm formation was observed in 174 (88.8 %) and in 145 (74.0%) isolates of&nbsp;S. aureus&nbsp;via TCP method and TM, respectively. The highest resistance percent was for penicillin (92.9%), followed by cefoxitin (80.6%) and oxacillin (67.9%), while the lowest resistance percent was for linezolid and ceftaroline (1%). Among the 196 isolates 71.4% (N=140) were classified as MDR with a MAR index (≥ 0.2). A total of 158 isolates (80.6%) were identified as MRSA distributed as 90.4%, 79.4% and 70.9% from Al-Shifa, Al-Nasser pediatrics and Al-Aqsa hospitals respectively. Large proportions (82.1%) of biofilm producers were identified as MRSA. Biofilm-producing&nbsp;MRSA&nbsp;exhibited a higher percent (90.5%) when compared with the biofilm non-producer MRSA (9.5%). Importantly, 89.2% of biofilm-producing&nbsp;S. aureus&nbsp;were multidrug resistant. Conclusions: S. aureus&nbsp;isolates possessed high biofilm-forming ability. Biofilm-producing strains have very high tendency to exhibit antimicrobial resistance, multidrug resistance and methicillin resistance. Regular surveillance of biofilm formation by&nbsp;S. aureus&nbsp;and their antimicrobial resistance profile may lead more success in treating S. aureus&nbsp;infections. &nbsp; Keywords:&nbsp;Biofilm, MDR, MRSA, TCP, TM, Gaza strip, Palestine