Study of Various Virulence Genes, Biofilm Formation and Extended-Spectrum β-lactamase Resistance in Klebsiella pneumoniae Isolated from Urinary Tract Infections

Crippling of Klebsiella pneumoniae virulence by metformin, N-acetylcysteine and secnidazole

INTRODUCTION

The emergence of multidrug-resistant Klebsiella pneumoniae in hospitals represents a serious threat to public health. Infections caused by Klebsiella pneumoniae are widespread in healthcare institutions, mainly pneumonia, bloodstream infections, and infections affecting neonates in intensive care units; so, it is necessary to combat this pathogen with new strategies. Targeting virulence factors necessary to induce host damage and disease is a new paradigm for antimicrobial therapy with several potential benefits that could lead to decreased resistance.

BACKGROUND

The influence of metformin, N-acetylcysteine, and secnidazole on Klebsiella pneumoniae virulence factors production was tested. The production of Klebsiella pneumoniae virulence factors such as biofilm formation, urease, proteases, hemolysins, and tolerance to oxidative stress was evaluated phenotypically using sub-inhibitory concentration (1/8 MIC) of metformin, N-acetylcysteine, and secnidazole. For more confirmation, qRT-PCR was used to assess the relative expression level of rmpA, wcaG, fimH-1, mrkD, ureA, and khe genes regulating virulence factors production.

RESULTS

Metformin, N-acetylcysteine, and secnidazole were all found to have a powerful inhibitory effect on the production of virulence factors phenotypically. Our results showed a significant reduction in the expression level of rmpA, wcaG, fimH-1, mrkD, ureA, and khe genes. Furthermore, the tested drugs were investigated in vivo to inform their ability to protect mice against Klebsiella pneumoniae pathogenesis.

CONCLUSIONS

Metformin, N-acetylcysteine, and secnidazole inhibited the virulence of Klebsiella pneumoniae. Besides combating resistant Klebsiella pneumoniae, the tested drugs could also serve as an adjuvant to traditional antibiotics.

Biotyping, Virulotyping and Biofilm Formation Ability of ESBL-Klebsiella pneumoniae Isolates from Nosocomial Infections

The aim of this study was to investigate the frequency, molecular characterization, virulence genes, resistance genes and antimicrobial profile of nosocomial extended spectrum beta lactamase producing Klebsiella species. A total of 22 (12.2%) K. pneumoniae strains were isolated from 180 clinical samples collected from hospitalized patients in Egypt. K. pneumoniae biotypes were B1 (72.8%), B3 (13.6%) and B4 (13.6%). The isolates were classified for the capsular serotypes, 86.4% (20/22) were of K1 serotype, while only two isolates (13.64%) were of K2 serotype. Hypermucoviscous K. pneumoniae isolates accounted for 68.2%. Biofilm formation ability of K. pneumoniae was determined by microtitre plate method. The majority of the isolates (40.9%) were moderate biofilm producers, while 27.3% were strong biofilm producers. All K. pneumoniae strains were positive for fimH and traT genes, while magA was identified in only 63.6% of the isolates. The antibiotic susceptibility profile of the isolates (n=22) was determined by the disc diffusion technique using 23 different antibiotics. Streptomycin and imipenem are the most effective antibiotics against 22 tested K. pneumoniae isolates with sensitivity rates of 63.64% and 54.54%, respectively. All tested K. pneumoniae isolates showed high resistance to amoxicillin∕clavulanate (100%), cefuroxime (100%) and ceftazidime (95.45%). Extended spectrum beta lactamases (ESBL) production and the presence of ESBL related genes were tested in the isolates. All the isolates tested positive for blaVIM, NDM1, and blaTEM, while only 81.8 percent tested positive for the blaSHV gene. Increasing antimicrobial resistance in K. pneumoniae causing nosocomial infections limits the use of antimicrobial agents for treatment. Furthermore, the spread of biofilm, multiple drug resistant and ESBL-producing K. pneumoniae isolates is a public threat for hospitalized patients.

Antibacterial and Anti-Biofilm Activities of Essential Oil Compounds against New Delhi Metallo-β-Lactamase-1-Producing Uropathogenic Klebsiella pneumoniae Strains

The World Health Organization points out that the opportunistic pathogen Klebsiella pneumoniae that causes various infections among others, urinary tract infections (UTIs), is one of the high-priority species due to a global problem of antimicrobial resistance. The aim of this study was to investigate antibacterial and anti-biofilm activities of chosen constituents of essential oils against NDM-1-producing, uropathogenic K. pneumoniae strains. The genes encoding lipopolysaccharide (uge, wabG), adhesin gene fimH (type I fimbriae) and gene encoding carbapenemase (blaNDM-1) for all tested strains were detected by PCR amplification. The K. pneumoniae ATCC BAA-2473 reference strain was uge- and blaNDM-1-positive. The effectiveness of fifteen essential oil compounds (EOCs) (linalool, β-citronellol, linalyl acetate, menthone, (−)-menthol, (+)-menthol, geraniol, eugenol, thymol, trans-anethole, farnesol, β-caryophyllene, (R)-(+)-limonene, 1,8-cineole, and carvacrol) was assessed by determining the MIC, MBC, MBC/MIC ratio against K. pneumoniae strains by the microdilution method. Anti-biofilm properties of these compounds were also investigated. Thymol, carvacrol and geraniol exhibited the best antibacterial and anti-biofilm activities against uropathogenic NDM-1-producing K. pneumoniae isolates. Results of our investigations provide a basis for more detailed studies of these phytochemicals on their application against uropathogenic K. pneumoniae.

Epidemiological features of nosocomial Klebsiella pneumoniae: virulence and resistance determinants

Aim: The authors aimed to examine antibiotic resistance genes and representative virulence determinants among 100 Klebsiella pneumoniae isolates with an emphasis on capsular serotypes and clonality of some of the isolates. Methods: PCR amplification of (rmpA, rmpA2, iutA, iroN and IncHI1B plasmid) and (NDM, OXA-48, KPC, CTX-M-15, VIM, IMP, SPM) was conducted. Wzi sequencing and multilocus sequence typing (MLST) were performed. Results: K2 was the only detected serotype in the authors' collection. RMPA2 was the most common capsule-associated virulence gene detected. All studied isolates harbored OXA-48-like (100%) and NDM (43%) (n = 43). ST147 was the most common sequence type. Conclusion: This work provides insight into the evolution of the coexistence of virulence and resistance genes in a tertiary healthcare setting in Cairo, Egypt.