Mrs. Mahnaz Ghahramani Til, Mrs. Rezvaneh Sadat Fatemi, Dr. Rahman Shokri, Dr. Mahdi Banitalebi Dehkordi, Dr. Mahdi Paryan,
Volume 25, Issue 4 (9-2022)
Abstract
Introduction: Salmonella infection (salmonellosis) is a common bacterial disease that affects the intestinal tract. Several methods like Multiplex or real-time PCR, ELISA, and Agglutination are used to identify these bacteria. However, normally rapid, cost effective and easy diagnostic methods such as agglutination test is recommended. In Iran, positive control antiserums used in diagnostic kits work based on polyvalent agglutination and are against O and H antigens. The purpose of this research was to produce specific anti-sera against O and H antigens for using in agglutination and ELISA kits.
Methods: New Zealand white rabbits were immunized by intravenous injections of inactivated bacterial O and H antigens adjusted to a cell density equivalent to a turbidity of a McFarland number 3 standard. Serum collection was performed 7 days after the last injection. Collected Antisera were tested with positive human specimens as well as cross-reaction antibodies. Absorption method was used to obtain specific anti-sera against O and H antigens. Produced Anti-O and Anti-H antibodies were mixed with bacterial H and O antigens respectively and incubated for 1 hours in 37˚c. The Mixture was centrifuged and the supernatant was collected. Furthermore, in order to use these antisera in specific kits such as ELISA, Immunofluorescence etc., purification methods like Ammonium sulphate precipitation, tangential Flow Filtration and Chromatography were performed. This study was approved by the ethics committee of Pasteur Institute of Iran (Code: IR.PII.REC.1399.006).
Results: Results of agglutination test before and after adsorption showed cross-reaction before adsorption and no cross-reaction with H and O antigens with monospecific antisera against O and H after adsorption, respectively. Moreover, high quality and quantity of mono-specific antibody was obtained after purification.
Conclusions: Serum-based assays are recommended for the timely diagnosis of the disease since these assays are specific, sensitive, inexpensive, and rapid. Therefore, the produced antiserum in the present research can be used in primary screening of salmonella infections based on agglutination tests which are cost effective and simple. In addition, purified anti-sera can be used in the development of ELISA and Immunofluorescence assays.
Ali Moradpoor Shamami, Dr Masumeh Anvari, Seyedeh Tooba Shafighi, Hadi Sedigh Ebrahim-Saraie,
Volume 25, Issue 5 (12-2022)
Abstract
Introduction: Considering the importance of urinary tract infections caused by uropathogenic Escherichia coli (UPEC) in the medical field, this study aimed to investigate serogroups O25 and O16 and the pattern of antibiotic resistance among UPEC isolates obtained from hospitalized patients with urinary tract infections (UTIs) in Rasht hospitals.
Methods: A total of 110 urine samples were collected from patients with UTIs referred to selected hospitals in Rasht. The disk diffusion method, as recommended by the CLSI, was used to determine the pattern of antibiotic susceptibility. Serogroups O25 and O16 were detected using specific primers.
Results: Among the studied samples, 36.4% (40/110) were men and 63.6% (70/110) were women. Based on the antibiotic susceptibility pattern, a high level of antibiotic resistance was observed against nalidixic acid (81.8%) and co-trimoxazole (78.2%), while the most effective antibiotics were amikacin (85.5%) and nitrofurantoin (83.6%). In addition, multi-drug resistant phenotype was found in 72.7% (110/80) of UPEC isolates. According to PCR results, the frequency of serogroups O25 and O16 was 36.4% and 17.3%, respectively. Both serogroups had the highest resistance to nalidixic acid and co-trimoxazole, while the lowest resistance in serogroup O25 to nitrofurantoin (20%) and amikacin (14.3%) and in serogroup O16 to imipenem (5.3%) and nitrofurantoin (10.5%).
Conclusions: This study showed that the high prevalence of MDR strains among UPEC strains is very worrying and professionals should be very careful in prescribing antibiotics for patients. Like most studies, the frequency of serogroup O25 was high, and probably, this serogroup can play a role in causing urinary tract infections and antibiotic resistance of UPEC strains.
