Characterization of Small Colony Variants of Klebsiella pneumoniae

Dania, Hassan,; Magaogao, Michael; Hossain, Ashfaque

doi:10.4103/bbrj.bbrj_154_22

Cited by 3 publications

(1 citation statement)

References 23 publications

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“…Also, many researchers have shown a link between biofilm creation ability and resistance to certain antimicrobial agents [ 71 – 73 ]. The emergence of small colony variants (SCVs), which remain viable inside the bacterial population at a slow growth rate, has been reported to be associated with special biofilm formation abilities and MDR [ 74 ]. A bacterial switch to the SCV phenotype provides a significant colonization advantage, causing recurrent and aggressive infection.…”

Section: Discussionmentioning

confidence: 99%

Vitamin D and vitamin K1 as novel inhibitors of biofilm in Gram-negative bacteria

Lutfi,

Shaaban,

Elshaer

2024

BMC Microbiol

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Background The persistent surge in antimicrobial resistance represents a global disaster. The initial attachment and maturation of microbial biofilms are intimately related to antimicrobial resistance, which in turn exacerbates the challenge of eradicating bacterial infections. Consequently, there is a pressing need for novel therapies to be employed either independently or as adjuvants to diminish bacterial virulence and pathogenicity. In this context, we propose a novel approach focusing on vitamin D and vitamin K1 as potential antibiofilm agents that target Gram-negative bacteria which are hazardous to human health. Results Out of 130 Gram-negative bacterial isolates, 117 were confirmed to be A. baumannii (21 isolates, 17.9%), K. pneumoniae (40 isolates, 34.2%) and P. aeruginosa (56 isolates, 47.9%). The majority of the isolates were obtained from blood and wound specimens (27.4% each). Most of the isolates exhibited high resistance rates to β-lactams (60.7–100%), ciprofloxacin (62.5–100%), amikacin (53.6–76.2%) and gentamicin (65-71.4%). Approximately 93.2% of the isolates were biofilm producers, with 6.8% categorized as weak, 42.7% as moderate, and 50.4% as strong biofilm producers. The minimum inhibitory concentrations (MICs) of vitamin D and vitamin K1 were 625–1250 µg mL-1 and 2500–5000 µg mL-1, respectively, against A. baumannii (A5, A20 and A21), K. pneumoniae (K25, K27 and K28), and P. aeruginosa (P8, P16, P24 and P27) clinical isolates and standard strains A. baumannii (ATCC 19606 and ATCC 17978), K. pneumoniae (ATCC 51503) and P. aeruginosa PAO1 and PAO14. Both vitamins significantly decreased bacterial attachment and significantly eradicated mature biofilms developed by the selected standard and clinical Gram-negative isolates. The anti-biofilm effects of both supplements were confirmed by a notable decrease in the relative expression of the biofilm-encoding genes cusD, bssS and pelA in A. baumannii A5, K. pneumoniae K28 and P. aeruginosa P16, respectively. Conclusion This study highlights the anti-biofilm activity of vitamins D and K1 against the tested Gram-negative strains, which emphasizes the potential of these vitamins for use as adjuvant therapies to increase the efficacy of treatment for infections caused by multidrug-resistant (MDR) strains and biofilm-forming phenotypes. However, further validation through in vivo studies is needed to confirm these promising results.

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Section: Discussionmentioning

confidence: 99%

Vitamin D and vitamin K1 as novel inhibitors of biofilm in Gram-negative bacteria

Lutfi,

Shaaban,

Elshaer

2024

BMC Microbiol

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Distribution of Carbapenemase Genes among Carbapenem-Resistant Klebsiella pneumoniae Isolates from the Patients in Najaf, Iraq

Mohanna,

AL-Yasseen

2024

Biomedical and Biotechnology Research Journal

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Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a global threat, causing serious community- and hospital-acquired infections with limited treatment options. Understanding the local epidemiology of CRKP is crucial for guiding antimicrobial stewardship and infection control measures. This study aimed to investigate the phenotypic characteristics, antimicrobial resistance profiles, and carbapenemase genes among CRKP isolates from the patients in Najaf, Iraq. Methods: This cross-sectional research was performed at diverse hospitals and centers in Najaf, Iraq, from September 2023 to March 2024. The study was approved by the Ethics Committee of Kufa University. CRKP isolates were collected from various health-care facilities and tested for hypermucoviscosity, antimicrobial susceptibility, and carbapenemase production using phenotypic methods. The presence of carbapenemase genes (blaNDM, blaVIM, blaKPC, blaOXA-48, blaOXA-23, and blaOXA-51) was examined by polymerase chain reaction. Results: Of the 27 CRKP isolates, 9 (33.3%) exhibited a hypermucoviscous phenotype. Regarding antimicrobial resistance, 12 (44.4%) were multidrug resistant, 14 (51.9%) were extensively drug resistant, and 1 (3.7%) was pandrug resistant. Phenotypic carbapenemase production was detected in 5 (18.5%) and 11 (40.7%) isolates by the modified Hodge test and E-test metallo-β-lactamase strips, respectively. Molecular analysis revealed that all CRKP harbored the blaOXA-51 gene, whereas blaNDM, blaOXA-23, and blaVIM were detected in 70.4%, 40.7%, and 11.1% of the isolates, respectively. Neither blaKPC nor blaOXA-48 genes were found. In addition, 22 (81.5%) isolates carried multiple carbapenemase genes. Conclusions: The high prevalence of blaOXA-51 and blaNDM carbapenemases, along with the high rates of multidrug resistance among CRKP isolates in Najaf, Iraq, are alarming. This necessitates the immediate implementation of effective antimicrobial stewardship and infection control measures to prevent the further spread of these difficult-to-treat pathogens.

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Plasmid-mediated AmpC β-Lactamase Gene Analysis in Klebsiella Pneumoniae Clinical Isolates

Jomehzadeh

Ahmadi

Shaabaninejad

et al. 2022

Biomedical and Biotechnology Research Journal (BBRJ)

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Background: In Gram-negative bacteria, including Klebsiella pneumoniae, the production of AmpC beta-lactamase enzymes is one of the main resistance mechanisms for beta-lactam antibiotics. This study aimed to investigate the phenotypic and molecular characteristics of AmpC beta-lactamases in K. pneumoniae clinical isolates in Southwest Iran. Methods: This study was conducted on 55 K. pneumoniae strains collected from various clinical samples. Identification of isolates was done using routine bacteriological and biochemical tests. After performing the antibiotic sensitivity test, the cefoxitin-resistant strains were analyzed using the phenotypic test in terms of the production of AmpC beta-lactamase enzymes. Finally, the frequency of plasmid-mediated AmpC genes was determined using a polymerase chain reaction test. Results: Out of the 55 isolates, 63.6% (n = 35) were obtained from urine, 9.1% (n = 5) from blood, 12.7% (n = 7) from wounds, and 14.6% (n = 8) from sputum. The highest resistance rate was observed against amoxicillin (98.2%), followed by cefotaxime (78.2%) and ceftriaxone (72.7%). According to the phenotypic tests, the prevalence of AmpC producers was 25.4%. Of all isolates, 36.3% (20/55) harbored different AmpC-associated genes, and bla MOX, bla CIT, bla EBC, and bla DHA genes were detected in 1, 2, 8, and 13 strains, respectively. None of the isolates harbored bla ACC and bla FOX genes. Conclusion: It is important to revise the prescription policy of effective antibiotics in this region, since a significant prevalence of AmpC beta-lactamase-producing isolates has made antibiotic resistance a serious concern.

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Characterization of Small Colony Variants of Klebsiella pneumoniae

Cited by 3 publications

References 23 publications

Vitamin D and vitamin K1 as novel inhibitors of biofilm in Gram-negative bacteria

Vitamin D and vitamin K1 as novel inhibitors of biofilm in Gram-negative bacteria

Distribution of Carbapenemase Genes among Carbapenem-Resistant Klebsiella pneumoniae Isolates from the Patients in Najaf, Iraq

Plasmid-mediated AmpC β-Lactamase Gene Analysis in Klebsiella Pneumoniae Clinical Isolates

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