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636600.9874Fluorinated Beta-diketo Phosphorus Ylides Are Novel Efflux Pump Inhibitors in Bacteria. BACKGROUND: One of the most important resistance mechanisms in bacteria is the increased expression of multidrug efflux pumps. To combat efflux-related resistance, the development of new efflux pump inhibitors is essential. MATERIALS AND METHODS: Ten phosphorus ylides were compared based on their MDR-reverting activity in multidrug efflux pump system consisting of the subunits acridine-resistance proteins A and B (AcrA and AcrB) and the multidrug efflux pump outer membrane factor TolC (TolC) of Escherichia coli K-12 AG100 strain and its AcrAB-TolC-deleted strain. Efflux inhibition was assessed by real-time fluorimetry and the inhibition of quorum sensing (QS) was also investigated. The relative gene expression of efflux QS genes was determined by real-time reverse transcriptase quantitative polymerase chain reaction. RESULTS: The most potent derivative was Ph(3)P=C(COC(2)F(5))CHO and its effect was more pronounced on the AcrAB-TolC-expressing E. coli strain, furthermore the most active compounds, Ph(3)P=C(COCF(3))OMe, Ph(3)P=C(COC(2)F(5))CHO and Ph(3)P=C(COCF(3))COMe, reduced the expression of efflux pump and QS genes. CONCLUSION: Phosphorus ylides might be valuable EPI compounds to reverse efflux related MDR in bacteria.201627815466
227410.9864Contribution of genetic factors towards cefotaxime and ciprofloxacin resistance development among Extended spectrum beta-lactamase producing-Quinolone resistant pathogenic Enterobacteriaceae. β-lactams and quinolones are widely utilised to treat pathogenic Enterobacterial isolates worldwide. Due to improper use of these antibiotics, both ESBL producing and quinolone resistant (ESBL-QR) pathogenic bacteria have emerged. Nature of contribution of beta-lactamase (bla)/quinolone resistant (QR) genes, efflux pumps (AcrAB-TolC) over-expression and outer membrane proteins (OMPs) /porin loss/reduction and their combinations towards development of this phenotype were explored in this study. Kirby-Bauer disc diffusion method was used for phenotypic characterization of these bacteria and minimum inhibitory concentration of cefotaxime and ciprofloxacin was determined by broth micro dilution assay. Presence of bla, QR, gyrA/B genes was examined by PCR; acrB upregulation by real-time quantitative PCR and porin loss/reduction by SDS-PAGE. Based on antibiogram, phenotypic categorization of 715 non-duplicate clinical isolates was: ESBL(+)QR(+) (n = 265), ESBL(+)QR(-) (n = 6), ESBL(-)QR(+) (n = 346) and ESBL(-)QR(-)(n = 11). Increased OmpF/K35 and OmpC/K36 reduction, acrB up-regulation, prevalence of bla, QR genes and gyrA/B mutation was observed among the groups in following order: ESBL(+)QR(+)> ESBL(-)QR(+)> ESBL(+)QR-> ESBL(-)QR(-). Presence of bla gene alone or combined porin loss and efflux pump upregulation or their combination contributed most for development of a highest level of cefotaxime resistance of ESBL(+)QR(+) isolates. Similarly, combined presence of QR genes, porin loss/reduction, efflux pump upregulation and gyrA/B mutation contributed towards highest ciprofloxacin resistance development of these isolates.202437884102
618220.9861An RND-type multidrug efflux pump SdeXY from Serratia marcescens. OBJECTIVES: Serratia marcescens, an important cause of nosocomial infections, shows intrinsic resistance to a wide variety of antimicrobial agents (multidrug resistance). Multidrug efflux pumps are often involved in the multidrug resistance in many bacteria. A study was undertaken to characterize the multidrug efflux pumps in S. marcescens. METHODS: The genes responsible for the multidrug resistance phenotype in S. marcescens were cloned into Escherichia coli KAM32, a drug-hypersusceptible strain, for further analysis. RESULTS: We cloned sdeXY genes and determined the nucleotide sequence. Clones that carried the sdeXY genes displayed reduced susceptibility to several antimicrobial agents including erythromycin, tetracycline, norfloxacin, benzalkonium chloride, ethidium bromide, acriflavine and rhodamine 6G. A protein similarity search using GenBank revealed that SdeY is a member of the resistance nodulation cell-division (RND) family of multidrug efflux proteins and SdeX is a member of the membrane fusion proteins. Introduction of sdeXY into E. coli cells possessing tolC, but not in cells lacking tolC, resulted in multidrug resistance. We observed energy-dependent ethidium efflux in cells of E. coli KAM32 possessing sdeXY and tolC. CONCLUSIONS: SdeXY is the first RND-type multidrug efflux pump to be characterized in multidrug-resistant S. marcescens.200312837741
227630.9860Role of gyrase A/B double mutations along with Qnr genes in development of higher ciprofloxacin resistance among pathogenic Escherichia coli and Klebsiella pneumoniae. Contribution of quinolone resistant (QR) genes, efflux pumps (AcrB) over-expression and outer membrane proteins (OMPs) loss/reduction, gyrA/B mutation towards development of quinolone resistance of pathogenic E.coli and Klebsiella sp was explored. Phenotypic characterization of 715 bacteria, isolated from Indian patients during 2011-2017 was performed by Kirby-Bauer disc diffusion assay. Minimum inhibitory concentration of ciprofloxacin was determined by broth microdilution assay. Presence of QR, gyrA/B genes was examined by PCR; acrB upregulation by quantitative PCR and porin profile by SDS-PAGE. Catalytic pockets of modelled proteins were characterized and their interaction with ciprofloxacin was analyzed using AutoDock. Isolates were phenotypically categorized into QR1-QR4 groups according to their resistance against single-four quinolones. Percent prevalence of QR-genes among isolates increased gradually with resistance against increasing number of quinolone antibiotics. Gradual increase in % partial reduction/complete loss of porins was observed from QR1 to QR4 groups with highest fold of Omp reduction. Similar trend was also observed in % prevalanace of upregulated acrB genes among these phenotypic groups with highest fold of upregulation observed among QR2 group. Isolates with GyrA-Ser83Leu + Asp87Asn and GyrB-Asn440Thr + Ser463Ala mutants harbouring Qnr genes mostly demonstrated highest MICs. This is also evident from greater hydrolytic efficiency (ΔG◦ value) of double mutants than their wild types. Dislocation of drug binding site among mutated-GyrA might explain their lower affinity towards quinolones -thus lowering their drug susceptibility. These findings underscore GyrA/B double mutants' role in higher QR among pathogenic E.coli and Klebsiella species, which might guide future antimicrobial therapy.202540784534
636740.9859Comparative Drug Resistance Reversal Potential of Natural Glycosides: Potential of Synergy Niaziridin & Niazirin. BACKGROUND: Due to the limited availability of antibiotics, Gram-negative bacteria (GNB) acquire different levels of drug resistance. It raised an urgent need to identify such agents, which can reverse the phenomenon of drug resistance. OBJECTIVE: To understand the mechanism of drug resistance reversal of glycosides; niaziridin and niazirin isolated from the pods of Moringa oleifera and ouabain (control) against the clinical isolates of multidrug-resistant Escherichia coli. METHODS: The MICs were determined following the CLSI guidelines for broth micro-dilution. In-vitro combination studies were performed by broth checkerboard method followed by Time-Kill studies, the efflux pump inhibition assay, ATPase inhibitory activity, mutation prevention concentration and in-silico studies. RESULTS: The results showed that both glycosides did not possess antibacterial activity of their own, but in combination, they reduced the MIC of tetracycline up to 16 folds. Both were found to inhibit efflux pumps, but niaziridin was the best. In real time expression pattern analysis, niaziridin was also found responsible for the down expression of the two important efflux pump acrB & yojI genes alone as well as in combination. Niaziridin was also able to over express the porin forming genes (ompA & ompX). These glycosides decreased the mutation prevention concentration of tetracycline. CONCLUSION: This is the first ever report on glycosides, niazirin and niaziridin acting as drug resistance reversal agent through efflux pump inhibition and modulation of expression pattern drug resistant genes. This study may be helpful in preparing an effective antibacterial combination against the drug-resistant GNB from a widely growing Moringa oleifera.201930977451
229350.9857Mechanisms of Resistance in Clinical Isolates of Enterobacter cloacae that Are Less Susceptible to Cefepime than to Ceftazidime. Thirty-two Enterobacter cloacae strains that are less susceptible to cefepime than to ceftazidime were collected. This unique phenotype of 8 strains was confirmed using the agar dilution method. OXA1, OXA10, OXA31 and OXA35 were detected in 3, 2, 3, and 2 strains, respectively, whereas all strains were negative for PSE-1 genes. OXA genes were also identified in the plasmid DNA of 5 strains, but only 2 strains were positive in a conjugation experiment. The acrA, acrB and tolC genes were identified in 4, 4 and 6 strains, respectively. Decreased expression of the acrA mRNA and overexpression of the acrB and tolC mRNAs were observed using real-time RT-PCR. Most of the bacteria (n=7) stably expressed the marA gene, which is a regulatory gene in the AcrAB-TolC multidrug efflux system, whereas all strains were negative for ramA. The acrA, acrB, tolC, acrR and marA genes were similar to the genes in reference strains in GenBank, with nucleotide homologies of 96%, 98%, 98%, 98% and 100%, respectively. In conclusion, the mechanism of resistance of Enterobacter cloacae with less susceptibility to cefepime than to ceftazidime is associated with the overexpression of AcrAB-TolC and the production of OXA1, XA10, OXA31 and OXA35.201829970440
619060.9856Identifying Escherichia coli genes involved in intrinsic multidrug resistance. Multidrug resistance is a major cause of clinical failure in treating bacterial infections. Increasing evidence suggests that bacteria can resist multiple antibiotics through intrinsic mechanisms that rely on gene products such as efflux pumps that expel antibiotics and special membrane proteins that block the penetration of drug molecules. In this study, Escherichia coli was used as a model system to explore the genetic basis of intrinsic multidrug resistance. A random mutant library was constructed in E. coli EC100 using transposon mutagenesis. The library was screened by growth measurement to identify the mutants with enhanced or reduced resistance to chloramphenicol (Cm). Out of the 4,000 mutants screened, six mutants were found to be more sensitive to Cm and seven were more resistant compared to the wild-type EC100. Mutations in 12 out of the 13 mutants were identified by inverse polymerase chain reaction. Mutants of the genes rob, garP, bipA, insK, and yhhX were more sensitive to Cm compared to the wild-type EC100, while the mutation of rhaB, yejM, dsdX, nagA, yccE, atpF, or htrB led to higher resistance. Overexpression of rob was found to increase the resistance of E. coli biofilms to tobramycin (Tob) by 2.7-fold, while overexpression of nagA, rhaB, and yccE significantly enhanced the susceptibility of biofilms by 2.2-, 2.5-, and 2.1-fold respectively.200818807027
637170.9853Bioactive compounds from the African medicinal plant Cleistochlamys kirkii as resistance modifiers in bacteria. Cleistochlamys kirkii (Benth) Oliv. (Annonaceae) is a medicinal plant traditionally used in Mozambique to treat infectious diseases. The aim of this study was to find resistance modifiers in C. kirkii for Gram-positive and Gram-negative model bacterial strains. One of the most important resistance mechanisms in bacteria is the efflux pump-related multidrug resistance. Therefore, polycarpol (1), three C-benzylated flavanones (2-4), and acetylmelodorinol (5) were evaluated for their multidrug resistance-reverting activity on methicillin-susceptible and methicillin-resistant Staphylococcus aureus and Escherichia coli AG100 and AG100 A strains overexpressing and lacking the AcrAB-TolC efflux pump system. The combined effects of antibiotics and compounds (2 and 4) were also assessed by using the checkerboard microdilution method in both S. aureus strains. The relative gene expression of the efflux pump genes was determined by real-time reverse transcriptase quantitative polymerase chain reaction. The inhibition of quorum sensing was also investigated. The combined effect of the antibiotics and compound 2 or 4 on the methicillin-sensitive S. aureus resulted in synergism. The most active compounds 2 and 4 increased the expression of the efflux pump genes. These results suggested that C. kirkii constituents could be effective adjuvants in the antibiotic treatment of infections.201829464798
600980.9853Efflux pump inhibitor chlorpromazine effectively increases the susceptibility of Escherichia coli to antimicrobial peptide Brevinin-2CE. Aim: The response of E. coli ATCC8739 to Brevinin-2CE (B2CE) was evaluated as a strategy to prevent the development of antimicrobial peptide (AMP)-resistant bacteria. Methods: Gene expression levels were detected by transcriptome sequencing and RT-PCR. Target genes were knocked out using CRISPR-Cas9. MIC was measured to evaluate strain resistance. Results: Expression of acrZ and sugE were increased with B2CE stimulation. ATCC8739ΔacrZ and ATCC8739ΔsugE showed twofold and fourfold increased sensitivity, respectively. The survival rate of ATCC8739 was reduced in the presence of B2CE/chlorpromazine (CPZ). Combinations of other AMPs with CPZ also showed antibacterial effects. Conclusion: The results indicate that combinations of AMPs/efflux pump inhibitors (EPIs) may be a potential approach to combat resistant bacteria.202438683168
229490.9852Antimicrobial Resistance of Clinical Klebsiella pneumoniae Isolates: Involvement of AcrAB and OqxAB Efflux Pumps. BACKGROUND: Over the last several decades, the AcrAB and OqxAB efflux pumps have been found to cause multidrug resistance (MDR) in various bacteria, most notably Klebsiella pneumoniae. Antibiotic resistance surges with increased expression of the acrAB and oqxAB efflux pumps. METHODS: In accordance with CLSI guidelines, a disk diffusion test was carried out using 50 K. pneumoniae isolates obtained from various clinical samples. CT was computed in treated samples and compared to a susceptible ciprofloxacin strain (A111). The final finding is presented as the fold change in the target gene's expression in treated samples relative to a control sample (A111), normalized to a reference gene. As ΔΔCT = 0 and 2 to the power of 0 = 1, relative gene expression for reference samples is often set to 1 Results: The highest rates of resistance were recognized with cefotaxime (100%), cefuroxime (100%), cefepime (100%), levofloxacin (98%), trimethoprimsulfamethoxazole (80%), and gentamicin (72%), whereas imipenem (34%) had the lowest rates. Overexpression of acrA and acrB, oqxA and oqxB, regulators marA, soxS, and rarA were greater in ciprofloxacin-resistant isolates compared to the reference strain (strain A111). There was also a moderate connection between ciprofloxacin MIC and acrAB gene expression and a moderate connection between ciprofloxacin MIC and oqxAB gene expression. CONCLUSION: This work provides a deeper knowledge of the role of efflux pump genes, particularly acrAB and oqxAB, as well as transcriptional regulators marA, soxS, and rarA, in bacterial resistance to ciprofloxacin.202436999690
2459100.9852In vitro antimicrobial activity and resistance mechanisms of cefiderocol against clinical carbapenem-resistant gram-negative bacteria. BACKGROUND: The rise of carbapenem-resistant gram-negative bacteria (CRGNB) necessitates new therapeutic options such as cefiderocol. OBJECTIVE: To evaluate the in vitro efficacy of cefiderocol against clinical CRGNB and investigate associated resistance mechanisms. METHODS: A total of 370 CRGNB isolates were analyzed. Minimum inhibitory concentration (MIC) values were determined, and whole genome sequencing, efflux pump inhibition assays, and RT-qPCR were conducted to assess resistance-related mutations, gene loss, and expression changes. RESULTS: Cefiderocol demonstrated potent in vitro activity, with high susceptibility rates in C. freundii (100%), K. pneumoniae (93.3%), and E. hormaechei (92.2%), and notable activity against P. aeruginosa (80.0%) and Escherichia coli (76.8%). Efflux pump inhibition by Carbonyl Cyanide m-Chlorophenyl Hydrazone (CCCP) significantly reduced MICs in resistant strains. Key resistance mechanisms included β-lactamase gene variants (bla (OXA-66), bla (OXA-23), bla (SHV-12)), mutations in envZ, cirA, nuoC, ampC, and loss or altered expression of iron transporter genes (piuA, pirA, fepA). CONCLUSION: Cefiderocol is highly effective against CRGNB; however, resistance may arise through diverse mechanisms, including efflux pump activity. Continued surveillance of emerging resistance is essential to guide its optimal clinical use.202541113641
2337110.9851Klebsiella pneumoniae susceptibility to biocides and its association with cepA, qacΔE and qacE efflux pump genes and antibiotic resistance. BACKGROUND: Although antiseptics are some of the most widely used antibacterials in hospitals, there is very little information on reduced susceptibility to these biocides and its relationship with resistance to antibiotics. AIM: To determine the relationship between reduced susceptibility to biocides and the carriage of antiseptic resistance genes, cepA, qacΔE and qacE, as well as identifying the role of efflux pumps in conferring reduced susceptibility. METHODS: Susceptibility was assessed for five biocides: chlorhexidine, benzalkonium chloride, Trigene, MediHex-4, Mediscrub; and for 11 antibiotics against 64 isolates of Klebsiella pneumoniae. Susceptibility to all compounds was tested by the agar double dilution method (DDM) and the effect of efflux pumps on biocides determined by repeating the susceptibility studies in the presence of the efflux pump inhibitor carbonyl cyanide m-chlorophenyl hydrazone (CCCP). The presence of the cepA, qacΔE and qacE genes was identified by polymerase chain reaction. FINDINGS: The bacteria were not widely antibiotic resistant though a few showed reduced susceptibility to cefoxitin, chloramphenicol and rifampicin and later-generation cephalosporins but not to carbapenems. Biocide susceptibility, tested by DDM, showed that 50, 49 and 53 strains had reduced susceptibility to chlorhexidine, Trigene and benzalkonium chloride, respectively. The antiseptic resistance genes cepA, qacΔE and qacE were found in 56, 34 and one isolates respectively and their effects as efflux pumps were determined by CCCP (10 mg/L), which decreased the minimum inhibitory concentrations (MICs) of chlorhexidine and Medihex-4 by 2-128-fold but had no impact on the MICs of benzalkonium chloride, Trigene and Mediscrub. CONCLUSION: There was a close link between carriage of efflux pump genes, cepA, qacΔE and qacE genes and reduced biocide susceptibility, but not antibiotic resistance, in K. pneumoniae clinical isolates.201222498639
6372120.9850Sensitizing multi drug resistant Staphylococcus aureus isolated from surgical site infections to antimicrobials by efflux pump inhibitors. BACKGROUND: Staphylococcus aureus is a common hospital acquired infections pathogen. Multidrug-resistant Methicillin-resistant Staphylococcus aureus represents a major problem in Egyptian hospitals. The over-expression of efflux pumps is a main cause of multidrug resistance. The discovery of efflux pump inhibitors may help fight multidrug resistance by sensitizing bacteria to antibiotics. This study aimed to investigate the role of efflux pumps in multidrug resistance. METHODS: Twenty multidrug resistant S. aureus isolates were selected. Efflux pumps were screened by ethidium bromide agar cartwheel method and polymerase chain reaction. The efflux pump inhibition by seven agents was tested by ethidium bromide agar cartwheel method and the effect on sensitivity to selected antimicrobials was investigated by broth microdilution method. RESULTS: Seventy percent of isolates showed strong efflux activity, while 30% showed intermediate activity. The efflux genes mdeA, norB, norC, norA and sepA were found to play the major role in efflux, while genes mepA, smr and qacA/B had a minor role. Verapamil and metformin showed significant efflux inhibition and increased the sensitivity to tested antimicrobials, while vildagliptin, atorvastatin, domperidone, mebeverine and nifuroxazide showed no effect. CONCLUSION: Efflux pumps are involved in multidrug resistance in Staphylococcus aureus. Efflux pump inhibitors could increase the sensitivity to antimicrobials.202034394224
6181130.9849Two distinct major facilitator superfamily drug efflux pumps mediate chloramphenicol resistance in Streptomyces coelicolor. Chloramphenicol, florfenicol, and thiamphenicol are used as antibacterial drugs in clinical and veterinary medicine. Two efflux pumps of the major facilitator superfamily encoded by the cmlR1 and cmlR2 genes mediate resistance to these antibiotics in Streptomyces coelicolor, a close relative of Mycobacterium tuberculosis. The transcription of both genes was observed by reverse transcription-PCR. Disruption of cmlR1 decreased the chloramphenicol MIC 1.6-fold, while disruption of cmlR2 lowered the MIC 16-fold. The chloramphenicol MIC of wild-type S. coelicolor decreased fourfold and eightfold in the presence of reserpine and Phe-Arg-beta-naphthylamide, respectively. These compounds are known to potentiate the activity of some antibacterial drugs via efflux pump inhibition. While reserpine is known to potentiate drug activity against gram-positive bacteria, this is the first time that Phe-Arg-beta-naphthylamide has been shown to potentiate drug activity against a gram-positive bacterium.200919687245
2338140.9848Characterization of disinfectant susceptibility profiles among clinical isolates of Acinetobacter baumannii in Ardabil, Iran. Antimicrobial disinfectants have been extensively used to control hospital-acquired infections worldwide. Prolonged exposure to bacteria could promote resistance to antimicrobial disinfectants. This study evaluated the antimicrobial activity of four commonly used disinfectants; triclosan, chlorhexidine digluconate, benzalkonium chloride, and formaldehyde against Acinetobacter baumannii clinical isolates. This study also determined the prevalence and association of efflux pumps encoding genes qacE, qacED1, emrA, and aceI with tolerance to disinfectants. A total of 100 A. baumannii isolates were included in the current study. The antimicrobial disinfectants' minimum inhibitory concentration (MIC) was determined using an agar dilution method. Genes involved in resistance to disinfectants were investigated by PCR method. The benzalkonium chloride MICs ranged between 32 and 128 μg mL-1, chlorhexidine digluconate 8-64 μg mL-1, triclosan 1-32 μg mL-1, and formaldehyde 128 μg mL-1. Overall, the highest MIC90 value was identified for formaldehyde (128 μg mL-1), followed by benzalkonium chloride and chlorhexidine digluconate (64 μg mL-1, each one) and triclosan (4 μg mL-1). In the present study, the qacE, qacED1, emrA, and aceI genes were found in 91%, 55%, 100%, and 88% of isolates, respectively. The qacG gene was not identified in our A. baumannii isolates. The qacED1 gene was associated with higher MICs for all disinfectants tested (P < 0.05), while the qacE and aceI genes were associated with higher MICs for benzalkonium chloride and chlorhexidine. This study indicated that triclosan is the most effective disinfectant against A. baumannii isolates.202338063878
6185150.9845Effects of efflux transporter genes on susceptibility of Escherichia coli to tigecycline (GAR-936). The activity of tigecycline, 9-(t-butylglycylamido)-minocycline, against Escherichia coli KAM3 (acrB) strains harboring plasmids encoding various tetracycline-specific efflux transporter genes, tet(B), tet(C), and tet(K), and multidrug transporter genes, acrAB, acrEF, and bcr, was examined. Tigecycline showed potent activity against all three Tet-expressing, tetracycline-resistant strains, with the MICs for the strains being equal to that for the host strain. In the Tet(B)-containing vesicle study, tigecycline did not significantly inhibit tetracycline efflux-coupled proton translocation and at 10 microM did not cause proton translocation. This suggests that tigecycline is not recognized by the Tet efflux transporter at a low concentration; therefore, it exhibits significant antibacterial activity. These properties can explain its potent activity against bacteria with a Tet efflux resistance determinant. Tigecycline induced the Tet(B) protein approximately four times more efficiently than tetracycline, as determined by Western blotting, indicating that it is at least recognized by a TetR repressor. The MICs for multidrug efflux proteins AcrAB and AcrEF were increased fourfold. Tigecycline inhibited active ethidium bromide efflux from intact E. coli cells overproducing AcrAB. Therefore, tigecycline is a possible substrate of AcrAB and its close homolog, AcrEF, which are resistance-modulation-division-type multicomponent efflux transporters.200415155219
6374160.9845Determining the effect of a new truncated CecropinA-Magenin2 (CE-MA) hybrid peptide on the expression of multidrug-resistant (MDR) Mycobacterium tuberculosis efflux genes. A significant issue in treating bacterial infections is multidrug resistance (MDR) microbes. Drug efflux pumps that reduce cellular drug accumulation are frequently linked to drug resistance. In this study, we set out to determine the effects of CE-MA truncated peptide derivatives against MDR Mycobacterium tuberculosis. Following the assessment of the minimum inhibitory concentrations (MICs) of these peptides against MDR Mycobacterium tuberculosis, a Real-Time PCR was used to examine the expression of six drug efflux pump genes. Next, an MTT assay was performed to test the cytotoxicity of peptides against the A549 cell line. The outcomes demonstrated that CE-MA significantly upregulated gene expression of mmr, and Rv0876c (⩾ 4-fold) than untreated bacteria. Also, under CMt2 stress, significant overexpression of Rv0876c and drrA was seen. However, the results show that upregulation in CMt2-treated bacteria in comparison CE-MA treated bacteria is significantly less for genes tap (P < 0.05), mmr (P < 0.0001), and Rv0876c (P < 0.001). Meanwhile, CMt1 only upregulated the Rv0876c gene and downregulated gene expression of tap, drrA, and mmr. It was also found that all three peptides have no significant effect (P > 0.05) on changing the expression of genes drrC and pstB. Less than 10% of the A549 cell line was susceptible to the toxicity of CMt1 and CMt2 at their MICs range. Our results emphasize the significance of investigating novel peptide-based approaches to combat MDR Mycobacterium tuberculosis and point to these peptides as prospective candidates for additional research.202540178610
6189170.9844Characterization of all RND-type multidrug efflux transporters in Vibrio parahaemolyticus. Resistance nodulation cell division (RND)-type efflux transporters play the main role in intrinsic resistance to various antimicrobial agents in many gram-negative bacteria. Here, we estimated 12 RND-type efflux transporter genes in Vibrio parahaemolyticus. Because VmeAB has already been characterized, we cloned the other 11 RND-type efflux transporter genes and characterized them in Escherichia coli KAM33 cells, a drug hypersusceptible strain. KAM33 expressing either VmeCD, VmeEF, or VmeYZ showed increased minimum inhibitory concentrations (MICs) for several antimicrobial agents. Additional four RND-type transporters were functional as efflux pumps only when co-expressed with VpoC, an outer membrane component in V. parahaemolyticus. Furthermore, VmeCD, VmeEF, and VmeYZ co-expressed with VpoC exhibited a broader substrate specificity and conferred higher resistance than that with TolC of E. coli. Deletion mutants of these transporter genes were constructed in V. parahaemolyticus. TM32 (ΔvmeAB and ΔvmeCD) had significantly decreased MICs for many antimicrobial agents and the number of viable cells after exposure to deoxycholate were markedly reduced. Strains in which 12 operons were all disrupted had very low MICs and much lower fluid accumulation in rabbit ileal loops. These results indicate that resistance nodulation cell division-type efflux transporters contribute not only to intrinsic resistance but also to exerting the virulence of V. parahaemolyticus.201323894076
2161180.9844Detection of AcrA and AcrB Efflux Pumps in Multidrug-Resistant Klebsiella pneumonia that Isolated from Wounds Infection Patients in Al-Diwaniyah Province. Many infections produced by multidrug-resistant (MDR) Klebsiella pneumoniae are the main cause of death and treatment restrictions worldwide. In K. pneumoniae, the efflux pump system is dangerous in drug resistance. Therefore, this study was designed to investigate the involvement of the AcrA and AcrB efflux pumps in antibiotic resistance in Klebsiella pneumoniae isolated from wound patients. During June 2021-February 2022, 87 clinical isolates of Klebsiella pneumonia bacteria were obtained from wound samples patients consulted to the hospitals in AL-Diwaniyah province, Iraq. The disc diffusion method performed an antibiotic susceptibility test after microbiological/biochemical identification. The polymerase chain reaction (PCR) technique was used to examine efflux genes' prevalence (acrA and acrB). The results showed that resistance to Carbenicillin 72 (82.7%), Erythromycin 66 (75.8%), Rifampin 58 (66.6%), Ceftazidime 52 (59.7%), Cefotaxime 44 (50.5%), Novobiocin 38 (43.6%), Tetracycline 32 (36.7%), Ciprofloxacin 22 (25.2%), Gentamicin 16 (18.3%), Nitrofurantoin 6 (10.3%) in Klebsiella pneumoniae isolates. The PCR procedure revealed that the occurrence of the acrA and acrB genes is 55 (100%) and 55 (100%), respectively. The findings of this investigation show that the AcrA and AcrB efflux pumps play a crucial character in antibiotic resistance in multidrug-resistant Klebsiella pneumoniae bacterial isolates. As a result of the unintentional transmission of antimicrobial resistance genes, precise detection of resistance genes using molecular approaches is required to switch the extent of resistant strains.202337312720
5751190.9844The use of eugenol in combination with cefotaxime and ciprofloxacin to combat ESBL-producing quinolone-resistant pathogenic Enterobacteriaceae. AIM: Emergence of extended-spectrum beta-lactamase (ESBL) producing with quinolone-resistant (QR) pathogenic Enterobacteriaceae augmented the need to establish therapeutic options against them. Present study aimed towards determination of synergistic combination of eugenol (EG) with cefotaxime (CTX) and ciprofloxacin (CIP) to combat against this resistance and potentiation of antibacterial drugs by EG against these bacteria. METHODS AND RESULTS: Synergistic interaction between EG and CTX/CIP (FICI: 0·08-0·5) were observed among ESBL-QR bacteria using checkerboard assay. Approximately, 2- to 1024-fold minimum inhibitory concentration value reduction and 17- to 165 030-fold dose reduction index strongly suggested synergistic interaction between EG and antibiotics. Cell viability assay showed reduction in log(10) CFU per ml from 16·6 to 3·1 at synergistic concentration. Scanning electron microscopy further proved disruptive effect of EG on cell architecture. Eugenol and/or its combination also altered genes' expressions that imparted antibiotic resistance by ~1·6 to ~1226 folds. CONCLUSIONS: Reduced doses of antibiotics, bacterial morphological alterations, efflux pump down regulation, porin over expression and beta-lactamase gene inhibition of ESBL-QR bacteria by EG alone or in combination with CTX/CIP might have reversed antibiotic resistance profile of ESBL-QR bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided a molecular insight into action of EG and/with CTX and CIP, which might have potentiated antibiotic's activity against ESBL-QR bacteria.202032502298