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Acta Microbiologica et Immunologica Hungarica
Authors:
Ali Shivaee
,
Rokhsareh Mohammadzadeh
,
Shahla Shahbazi
,
Elahe Pardakhtchi
,
Elnaz Ohadi
, and
Behrooz Sadeghi Kalani

Staphylococcus epidermidis is an opportunistic pathogen causing infections related to the usage of implants and medical devices. Pathogenicity of this microorganism is mainly linked to its capability to form biofilm structures. Biofilm formation vastly depends on several factors including different proteins. We studied the expression levels of three proteins including SdrH, Bap, AtlE, and MazF at different time intervals during the course of biofilm formation. In this study, a catheter-derived S. epidermidis isolate with strong ability of biofilm formation was selected. PCR assay was used to detect sdrH, bap, atlE, and mazF genes in this isolate. Real-time PCR was used to determine the expression levels of these genes after 4, 8, and 20 h during the course of biofilm formation. The studied genes showed different expression levels at different time intervals during biofilm formation by real-time PCR method. Expression levels of atlE and sdrH genes were the highest at 4 h, whereas bap gene showed the highest expression level at 8 h during the course of biofilm formation. In addition, the expression level of mazF gene peaked at 4 h and then progressively decreased at 8 and 20 h. Our results suggest the importance of AtlE, SdrH, and MazF proteins in the establishment and development of the biofilm structure. In addition, our results showed the important role of protein Bap in the accumulation of biofilm structure. Future studies are required to understand the exact role of MazF in the process of biofilm formation.

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Acta Microbiologica et Immunologica Hungarica
Authors:
Shaghayegh Shahkolahi
,
Pegah Shakibnia
,
Shahla Shahbazi
,
Samira Sabzi
,
Farzad Badmasti
,
Mohammad Reza Asadi Karam
, and
Mehri Habibi

Abstract

In the present study a total of 200 Klebsiella pneumoniae isolates were collected from patients with urinary tract infections (UTIs) in Tehran, Iran. Antibiotic resistance was determined by disk diffusion and broth dilution methods. Detection of extended-spectrum β-lactamases (ESBLs) and AmpCs was performed using phenotypic tests. Polymerase chain reaction (PCR) was applied to detect the ESBL, AmpC, and integron genes. Analysis of AmpC and cassette arrays of integron genes was performed using DNA sequencing. Plasmids were analyzed by PCR-based replicon typing and conjugation. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were applied to explore the genomic relatedness among the isolates. The highest levels of resistance were observed against ampicillin (100%), followed by piperacillin (57.5%), ceftazidime (46%), trimethoprim/sulfamethoxazole (44%), ciprofloxacin (32.5%), and imipenem (19%). Approximately, 66.5% of isolates harbored at least one of the beta-lactamase genes (bla TEM, bla SHV, bla CTX-M, and bla OXA-1). In addition, 22.5% of isolates carried at least one of the AmpC genes including bla DHA and bla CIT. Integron class I was the most prevalent integron among resistant isolates. According to the results of replicon typing, IncFII, IncL/M, and IncA/C were the most frequent replicons, respectively. All selected isolates were able to transfer bla CTX-M, also two isolates transferred the bla DHA-1 gene to Escherichia coli K12 through conjugation. Finally, 21 isolates were categorized into 4 pulsotypes and 11 unique clusters in PFGE. MLST identified ST147 and ST11 sequence types but ST147 was the most prevalent in the current study.

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