Browsing by Author "Ashour, Hossam M"

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    Comparative genomic analysis of strong biofilm-forming Klebsiella pneumoniae isolates uncovers novel ISEcp1-mediated chromosomal integration of a full plasmid-like sequence
    (Taylor and Francis Ltd, 2024-01) Hamed, Samira M; Mohamed, Hend O; Ashour, Hossam M; Fahmy, Lamiaa I
    Background: The goal of the current study was to elucidate the genomic background of biofilm formation in Klebsiella pneumoniae. Methods: Clinical isolates were screened for biofilm formation using the crystal violet assay. Antimicrobial resistance (AMR) profiles were assessed by disk diffusion and broth microdilution tests. Biofilm formation was correlated to virulence and resistance genes screened by PCR. Draft genomes of three isolates that form strong biofilm were generated by Illumina sequencing. Results: Only the siderophore-coding gene iutA was significantly associated with more pronounced biofilm formation. ST1399-KL43-O1/O2v1 and ST11-KL15-O4 were assigned to the multidrug-resistant strain K21 and the extensively drug-resistant strain K237, respectively. ST1999-KL38-O12 was assigned to K57. Correlated with CRISPR/Cas distribution, more plasmid replicons and prophage sequences were identified in K21 and K237 compared to K57. The acquired AMR genes (bla OXA-48, rmtF, aac(6′)-Ib and qnrB) and (bla NDM-1, bla CTX-M, aph(3′)-VI, qnrS, and aac(6′)-Ib-cr) were found in K237 and K21, respectively. The latter showed a novel ISEcp1-mediated chromosomal integration of replicon type IncM1 plasmid-like structure harboring bla CTX-M-14 and aph(3′)-VI that uniquely interrupted rcsC. The plasmid-mediated heavy metal resistance genes merACDEPRT and arsABCDR were spotted in K21, which also exclusively carried the acquired virulence genes mrkABCDF and the hypervirulence-associated genes iucABCD-iutA, and rmpA/A2. Pangenome analysis revealed NTUH-K2044 accessory genes most frequently shared with K21. Conclusions: While less virulent to Galleria mellonella than ST1999 (K57), the strong biofilm former, multidrug-resistant, NDM-producer K. pneumoniae K21 (ST1399-KL43-O1/O2v1) carries a novel chromosomally integrated plasmid-like structure and hypervirulence-associated genes and represents a serious threat to countries in the area. © 2023 Society for Scandinavian Journal of Infectious Diseases.
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    The RND Efflux Pump Gene Expression in the Biofilm Formation of Acinetobacter baumannii
    (Multidisciplinary Digital Publishing Institute (MDPI), 2023-02) Abd El-Rahman, Ola A; Rasslan, Fatma; Hassan, Safaa S; Ashour, Hossam M; Wasfi, Reham
    Multidrug resistant (MDR) Acinetobacter baumannii is a critical opportunistic pathogen in healthcare-associated infections (HAI). This is attributed to several factors, including its ability to develop biofilms that can enhance antimicrobial resistance (AMR) in addition to creating an environment for horizontal transfer of antibiotic resistance genes. The role of the efflux pump in biofilm formation is important for studies on alternative treatments for biofilms. One of the significant efflux pump families is the RND efflux pump family, which is common in Gram negative bacteria. The aim is to study the role of the RND efflux pump in biofilm formation by A. baumannii. The biofilm formation potential of thirty-four MDR A. baumannii isolates was evaluated by crystal violet assays. The effect of efflux pump inhibition and activation was studied using the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and the RND efflux pump substrate levofloxacin (at sub-MIC), respectively. The isolates were genotypically grouped by enterobacterial repetitive intergenic consensus (ERIC) typing and the expression of adeABC, adeFGH, and adeIJK efflux pump genes was measured by qPCR. Overall, 85.2% (29/34) of isolates were biofilm producers (the phenotype was variable including strong and weak producers). Efflux pump inhibition by CCCP reduced the biofilm formation significantly (p < 0.05) in 20.5% (7/34) of some isolates, whereas sub-MICs of the substrate levofloxacin increased biofilm formation in 17.6% (6/34) of other isolates. Overexpression of the three RND efflux pump genes was detected in five out of eleven selected isolates for qPCR with remarkable overexpression in the adeJ gene. No correlation was detected between the biofilm phenotype pattern and the RND efflux pump gene expression in biofilm cells relative to planktonic cells. In conclusion, the role of the RND efflux pumps AdeABC, AdeFGH, and AdeIJK in biofilm formation does not appear to be pivotal and the expression differs according to the genetic background of each strain. Thus, these pumps may not be a promising target for biofilm inhibition.