محمد کتولی

Proteus mirabilis is the main pathogen causing complicated urinary tract infections (UTIs), especially catheter-associated UTIs (CAUTIs), which efficiently forms crystalline biofilm on different surfaces such as urethral indwelling catheters. The pathogenesis of P. mirabilis is related to its ability to produce a variety of virulence factors, such as biofilms, adhesion molecules, urease, hemolysin, swarming activity, proteases and siderophores. The aim of this study was to characterize the frequency of different virulence genes among biofilm producing uropathogenic P. mirabilis strains isolated from patients with UTI in a referral hospital in Isfahan during April-December 2022.

In this study a total of 50 P. mirabilis isolates were collected from urine samples of 50 patients with UTI in a referral hospital in Isfahan and confirmed using polymerase chain reaction (PCR) by specific primers for ureC and ureR genes. All strains were tested for their ability to form biofilm using quantitative microtiter plate (MTP) assay, and the frequency of different virulence associated genes (zapA, zapD, pta, hpmA, mrpA and hlyA) among biofilm producing strains was determined by specific primers.

All collected isolates were positive for ureC and ureR genes and confirmed as P. mirabilis. Also, all strains were able to form biofilm, in which 52, 44 and 4% of strains produced strong, moderate and weak biofilm, respectively. Moreover, zapA and zapD genes were detected in 100% of biofilm positive strains and the frequency of hpmA, pta and mrpA genes was limited to 96, 94 and 90% of strains. On the other hand, the hlyA gene was not detected in any studied P. mirabilis strains.

The high prevalence of biofilm producing P. mirabilis with a broad spectrum of virulence factors among patients with UTI in the studied hospital in Isfahan, indicating the clonal dissemination of biofilm producing pathogenic strains in Isfahan also the importance of P. mirabilis strains as a potential threat to patients’ health.

Urinary tract infection (UTI) is one of the most common bacterial infections, and a significant cause of morbidity in humans. Uropathogenic Escherichia coli (UPEC) is known as the primary cause of UTI and due to its ability to form biofilm results in high level resistance to different classes of antibiotics. Biofilm formation is a major determinant for the persistence and recurrence of UTI. In this study we aimed to determine the prevalence of biofilm producing UPECs and the relationship between antibiotic resistance and the quantity and quality of biofilm formation in patients with UTI in Isfahan.

During 2017, a total of 213 suspected E. coli isolates were collected from patients with UTI in a referral hospital in Isfahan and were identified using common biochemical and PCR confirmatory diagnostic tests. Production of curli/cellulose, and, biofilm formation was assessed using qualitative Congo red agar (CRA) and quantitative microtiter plate (MTP) methods, respectively. Biofilm producing strains were tested for susceptibility to 17 antibiotics using disk diffusion method by the guidelines of Clinical & Laboratory Standards Institute (CLSI).

A total of 166 strains (78%) were identified and confirmed as E. coli using common biochemical and PCR tests. According to the results of qualitative CRA and quantitative MTP assays, 39 strains (23%) were able to form curli and/or cellulose and were biofilm positive. The highest resistance rate of biofilm producing E. coli strains was against ampicillin followed by cefotaxime, cefpodoxime and ceftriaxone. On the other hand, carbapenems and aminoglycosides were also the most effective antibiotics against UPEC infections.

The results of the present study indicating the high prevalence of antibiotic resistant biofilm producing UPEC strains among patients with UTI in Isfahan. Moreover, a direct relationship between the strong biofilm production and high level antibiotic resistance was also found.

Biofilm formation is a major determinant factor in the development of urinary tract infections (UTIs) by uropathogenic Escherichia coli (UPEC). The ability of UPEC to form biofilm and produce beta-lactamases is linked to persistence and recurrence of UTIs. In this study, we investigated the prevalence of biofilm and beta-lactamase producing UPECs among patients with UTI in Zahedan.

During 2017, a total of 112 suspected E. coli isolates were collected from patients with UTIs in Imam Ali Hospital in Zahedan, and identified using common biochemical tests and also PCR by specific primers. The ability of confirmed strains to produce of curli/cellulose and form biofilm was assessed using qualitative Congo red agar (CRA) and quantitative microtiter plate (MTP) methods, respectively. Extended-spectrum beta-lactamase (ESBL) phenotypic production and antibiotic susceptibility of biofilm producing strains were investigated using disk diffusion method by the guidelines of CLSI.

A total of 85 isolates (76%) were identified and confirmed as UPEC strains using standard biochemical and molecular confirmatory diagnostic tests. The prevalence of BFP strains was very high, as 58 strains (68%) produced curli and/or cellulose and were able to produce biofilm. BFP strains showed high resistance (80-99%) to ampicillin, cefotaxime, cefpodoxime, ceftazidime and ceftriaxone. Moreover, 62% of strains were able to produce ESBL, and also a significant association between the strong biofilm and ESBL production was found.

The high prevalence of biofilm and ESBL producing UPEC strains isolated from patients with UTI in Zahedan, might be in part due to low socioeconomic status and also warm climate of this city.

Biofilm formation is a major determinant in the development of urinary tract infections (UTIs) by uropathogenic Escherichia coli (UPEC). Biofilm formation requires a set of genes facilitating the initial adhesion, maturation, production of the extracellular polymeric matrix and subsequent dispersal of bacteria. Several cell surface factors such as flagella, fimbriae, curli and exopolysaccharide production are involved in attachment of bacterial cells to the urinary tract and biofilm development. In this study we showed the prevalence of biofilm producing E. coli strains isolated from patients with UTI in Zahedan and also the presence of biofilm-associated genes was assessed.

During 2017, a total of 112 E. coli isolates were collected from patients with UTI in a referral hospital in Zahedan and were identified using common biochemical and PCR confirmatory diagnostic tests. The ability of E. coli strains to form curli and cellulose and also biofilm was measured using qualitative Congo red agar and quantitative microtiter plate assays, respectively. The presence of csgA, papC, fimH, sfaS and afaI biofilm-associated genes was tested by PCR assay.

A total of 85 strains (76%) were identified and confirmed as E. coli using PCR test. Amongst all, 58 strains (68%), produced curli and cellulose and were biofilm positive, in which, 7, 88 and 5% exhibited rdar, bdar and pdar morphotypes, respectively. Moreover, 52, 31 and 17% of strains were able to form strong, moderate and weak biofilm, respectively. The genes csgA, papC, fimH, sfaS and afaI were detected in 98, 79, 71, 14 and 10% of strains, respectively.

The results of the present study revealed the high prevalence of biofilm producing E. coli strains with biofilm associated genes among patients with UTI in Zahedan. The presence of such genes which are associated with bacterial attachment indicating the important role of curli and fimbria in biofilm formation during UTI infections which highlighted them as important targets for therapeutic purposes.

Urinary tract infections (UTIs) are some of the most common bacterial infections, and a significant cause of morbidity in all age groups that incur large financial costs to health-care systems. Uropathogenic Escherichia coli (UPEC) is the primary cause of UTIs and due to its high resistance to most classes of antibiotics, results in treatment failure. UPEC strains possess various virulence factors such as the ability to form biofilm which plays an important role in UTIs. The formation of biofilms by UPEC on or within bladder epithelial cells and as well as on urinary catheters is responsible for persistent infections which leading to recurrences. In this study we aimed to determine the prevalence of biofilm producing E. coli strains isolated from patients with UTI in Isfahan.

During 2017, a total of 213 E. coli isolates were collected from patients with UTI in a reference hospital in Isfahan and were identified using common biochemical and PCR confirmatory diagnostic tests. The ability of E. coli strains to form curli and cellulose was measured using qualitative Congo red agar assay and a quantitative microtiter plate assay was employed to test the biofilm forming capacity of the strains.

A total of 166 strains were identified and confirmed as E. coli using PCR test. Using qualitative Congo red agar plate assay, 127 strains (77%) exhibited saw morphotype and were not able to produce curli and cellulose. The other 39 strains (23%), produced curli and cellulose and were biofilm positive, in which, 38, 59 and 3% exhibited rdar, bdar and pdar morphotypes, respectively. Also, the results of microtiter plate assay showed that all of 39 curli and cellulose producing strains were biofilm positive in which 18, 26 and 56% of strains were able to form strong, moderate and weak biofilm, respectively.

The results of this study revealed the high prevalence of E. coli associated UTIs among different sexes and age groups in Isfahan. Biofilm production is closely related to antibiotic resistance and nowadays, biofilm forming UPEC strains are global public health concern. All strong biofilm producer UPEC strains, were able to form curli and cellulose simultaneously; which indicating the important role of these two compounds in the intensity of biofilm formation. Therefore, providing new therapeutic strategies and powerful compounds for destroying or inhibition of curli and cellulose will play an essential role in solving the clinical problems caused by biofilm of E. coli.

Staphylococcus aureus is known as community-acquired and nosocomial pathogen. Most of the isolates contain lysogenic phages and various virulence factors. The aim of the study was to analyze the antibiotic resistance pattern and detect the enterotoxin A gene among MRSA isolated from two hospitals in Tehran. Totally 94 isolates of methicillin resistant S. aureus were identified at the species level using specific primers. Susceptibility to seventeen antibiotics was determined using disc diffusion method and Minimum inhibitory concentration (MIC) of oxacillin and vancomycin in MRSA isolates were also detected using Etest. mecA and sea genes were detected using specific primers. Primers for identification of 6 classes of prophages were used in a Multiplex-PCR assay. The highest antibiotic resistance was observed to penicilli and followed by ciprofloxacin, erythromycin, kanamycin, amikacin, tobramycin, clindamycin and tetracycline. Five different prophage types were found in MRSA isolates and all MRSA isolates contained at least one prophage type. One hundred percent of the MRSA isolates contained sea and mecA genes. High prevalence of different classes of prophages, production of enterotoxin A and high resistance of MRSA isolates to first and second lines of treatments is a potential treat for public health.

Staphylococcus aureus is a common cause of infections among human and animals and known as community-acquired and nosocomial pathogen. MRSA infection has recently become a serious problem in anti-microbial chemotherapy. The aim of the study was to detect and analyze the antibiotic resistance pattern among MRSA isolated from six hospitals in Tehran in 2008-2011.

Totally 396 isolates of MRSA from clinical samples were collected from six hospitals in Tehran. All isolates were identified at the species level using specific primers. Susceptibility to seventeen antibiotics was determined using disc diffusion method. MIC of oxacillin and vancomycin in MRSA isolates was also done using Etest according to CLSI recommendation. PCR was used to detect mecA gene.

Using PCR all isolates were confirmed as MRSA. The highest level of resistance was observed to oxacillin, penicillin, ciprofloxacin, kanamycin, erythromycin, tobramycin and amikacin respectivelyMIC results showed that 86% of isolates showed high level resistant to oxacillin (MIC≥256 μg/ml). None of the MRSA isolates were resistant to vancomycin. One hundred percent of the isolates contained mecA gene.

This study showed that the prevalence of MRSA isolates is lower than the other studies in Iran. MRSA isolates showed resistance to broad spectrum of antibiotics. Synercid, linezolid, vancomycin and chloramphenicol are the most effective antibiotics against MRSA infections. Detection of mecA gene is a rapid and reliable method for identification of MRSA isolates.