scholarly journals Evaluation of the occurrence of genetic determinants of multi-drug resistance among Acinetobacter baumannii strains

2021 ◽  
pp. 15-23
Keyword(s):  
Drug Resistance ◽  
Acinetobacter Baumannii ◽  
Multiplex Pcr ◽  
Biofilm Formation ◽  
Insertion Sequence ◽  
Efflux Pump ◽  
Multi Drug Resistance ◽  
Genetic Determinants ◽  
Rapd Pcr ◽  
Pcr Method

Introduction: The aim of the study was the analysis of occurrence of genetic determinants of multi-drug resistance and the assessment of genetic relationship among Acinetobacter baumannii strains. Methods: Multiplex-PCR method was performed in order to: (1) confirm the phenotypic identification and (2) detect the presence of CHDL oxacillinases in the group of thirty A.baumannii strains. Further PCR studies included the analysis of the occurrence of genetic determinants associated with efflux pump, insertion sequence and biofilm formation. The relationship between bacterial strains was assayed using 6 primers in RAPD-PCR method. Results: Detection of the blaOXA-51-like gene confirmed that the strains belong to the A. baumannii species. In the multiplex-PCR, the presence of the blaOXA-23-like and blaOXA-40-like genes was detected in 3 (10%) and 27 (90%) isolates, respectively. Moreover, some strains showed the coexistence of the blaOXA-51-like and blaOXA-23-like genes (10%, n=3) or blaOXA-51-like and blaOXA-40-like (90%, n=27). In the group of analysed strains the presence of the efflux pump gene (adeA) and the insertion sequence ISAba1 were demonstrated in all tested isolates. Biofilm-related genes (abaI, csuE) were found in 100% and 97% (n=29) tested strains adequately. The RAPD-PCR studies revealed the presence of 10 unrelated genotypes. Conclusions: The obtained results suggest that the phenomenon of multi-drug resistance in the studied A. baumannii strains could be attributed to the occurrence of CHDL oxacillinases, AdeABC efflux pump, insertion sequence ISAba1 and the biofilm formation.

scholarly journals Impact of an Intervention to Control Imipenem-Resistant Acinetobacter baumannii and Its Resistance Mechanisms: An 8-Year Survey

2021 ◽  
Vol 11 ◽  
Author(s):  
Lida Chen ◽  
Pinghai Tan ◽  
Jianming Zeng ◽  
Xuegao Yu ◽  
Yimei Cai ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Acinetobacter Baumannii ◽  
Bacterial Resistance ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Multi Drug Resistance ◽  
Minimal Inhibitory Concentrations ◽  
Resistance Rates ◽  
The Impact

BackgroundThis study aimed to examine the impact of an intervention carried out in 2011 to combat multi-drug resistance and outbreaks of imipenem-resistant Acinetobacter baumannii (IRAB), and to explore its resistance mechanism.MethodsA total of 2572 isolates of A. baumannii, including 1673 IRAB isolates, were collected between 2007 and 2014. An intervention was implemented to control A. baumannii resistance and outbreaks. Antimicrobial susceptibility was tested by calculating minimal inhibitory concentrations (MICs), and outbreaks were typed using pulsed-field gel electrophoresis (PFGE). Resistance mechanisms were explored by polymerase chain reaction (PCR) and whole genome sequencing (WGS).ResultsFollowing the intervention in 2011, the resistance rates of A. baumannii to almost all tested antibiotics decreased, from 85.3 to 72.6% for imipenem, 100 to 80.8% for ceftriaxone, and 45.0 to 6.9% for tigecycline. The intervention resulted in a decrease in the number (seven to five), duration (8–3 months), and departments (five to three) affected by outbreaks; no outbreaks occurred in 2011. After the intervention, only blaAMPC (76.47 to 100%) and blaTEM–1 (75.74 to 96.92%) increased (P < 0.0001); whereas blaGES–1 (32.35 to 3.07%), blaPER–1 (21.32 to 1.54%), blaOXA–58 (60.29 to 1.54%), carO (37.50 to 7.69%), and adeB (9.56 to 3.08%) decreased (P < 0.0001). Interestingly, the frequency of class B β-lactamase genes decreased from 91.18% (blaSPM–1) and 61.03% (blaIMP–1) to 0%, while that of class D blaOXA–23 increased to 96.92% (P < 0.0001). WGS showed that the major PFGE types causing outbreaks each year (type 01, 11, 18, 23, 26, and 31) carried the same resistance genes (blaKPC–1, blaADC–25, blaOXA–66, and adeABC), AdeR-S mutations (G186V and A136V), and a partially blocked porin channel CarO. Meanwhile, plasmids harboring blaOXA–23 were found after the intervention.ConclusionThe intervention was highly effective in reducing multi-drug resistance of A. baumannii and IRAB outbreaks in the long term. The resistance mechanisms of IRAB may involve genes encoding β-lactamases, efflux pump overexpression, outer membrane porin blockade, and plasmids; in particular, clonal spread of blaOXA–23 was the major cause of outbreaks. Similar interventions may also help reduce bacterial resistance rates and outbreaks in other hospitals.

scholarly journals Bifunctional enzyme SpoT is involved in biofilm formation of Helicobacter pylori with multidrug resistance by upregulating efflux pump Hp1174 (gluP)

2018 ◽  
Author(s):  
Xiaoran Ge ◽  
Yuying Cai ◽  
Zhenghong Chen ◽  
Sizhe Gao ◽  
Xiwen Geng ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Helicobacter Pylori ◽  
Multidrug Resistance ◽  
Biofilm Formation ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Multi Drug Resistance ◽  
Bifunctional Enzyme ◽  
Average Expression Level ◽  
H Pylori

ABSTRACTThe drug resistance of Helicobacter pylori (H. pylori) is gradually becoming a serious problem. Biofilm formation is an important factor that leads to multidrug resistance in bacteria. The ability of H. pylori to form biofilms on the gastric mucosa has been known. However, there are few studies on the regulation mechanisms of H. pylori biofilm formation and multidrug resistance. Guanosine 3’-diphosphate 5’-triphosphate and guanosine 3’,5’-bispyrophosphate [(p)ppGpp] are global regulatory factors and are synthesized in H. pylori by the bifunctional enzyme SpoT. It has been reported that (p)ppGpp is involved in the biofilm formation and multidrug resistance of various bacteria. In this study, we found that SpoT also plays an important role in H. pylori biofilm formation and multidrug resistance. Therefore, it is necessary to carry out some further studies regarding its regulatory mechanism. Considering that efflux pumps are of great importance in the biofilm formation and multidrug resistance of bacteria, we tried to find if efflux pumps controlled by SpoT participate in these activities. Then, we found that Hp1174 (glucose/galactose transporter, gluP), an efflux pump of the MFS family, is highly expressed in biofilm-forming and multi-drug resistance (MDR) H. pylori and is upregulated by SpoT. Through further research, we determined that gluP involved in H. pylori biofilm formation and multidrug resistance. Furthermore, the average expression level of gluP in clinical MDR strains was considerably higher than that in clinical drug-sensitive strains. Taken together, our results revealed a novel molecular mechanism of H. pylori tolerance to multidrug.

scholarly journals Multi-drug resistance profiles and the genetic features of Acinetobacter baumannii isolates from Bolivia

2013 ◽  
Vol 7 (04) ◽  
pp. 323-328 ◽  
Author(s):  
Bruno Silvester Lopes ◽  
Lucia Gallego ◽  
Sebastian Giles Becket Amyes
Keyword(s):  
Drug Resistance ◽  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Efflux Pump ◽  
Fluoroquinolone Resistance ◽  
Multi Drug Resistance ◽  
Resistance Mutations ◽  
Aminoglycoside Resistance ◽  
Over Expression ◽  
Hospitalised Patients

Introduction: Acinetobacter baumannii is opportunistic in debilitated hospitalised patients. Because information from some South American countries was previously lacking, this study examined the emergence of multi-resistant A. baumannii in three hospitals in Cochabamba, Bolivia, from 2008 to 2009. Methodology: Multiplex PCR was used to identify the main resistance genes in 15 multi-resistant A. baumannii isolates. RT-PCR was used to measure gene expression. The genetic environment of these genes was also analysed by PCR amplification and sequencing. Minimum inhibitory concentrations were determined for key antibiotics and some were determined in the presence of an efflux pump inhibitor, 1-(1-napthylmethyl) piperazine. Results: Fourteen strains were found to be multi-resistant. Each strain was found to have the blaOXA-58 gene with the ISAba3-like element upstream, responsible for over-expression of the latter and subsequent carbapenem resistance. Similarly, ISAba1, upstream of the blaADC gene caused over-expression of the latter and cephalosporin resistance; mutations in the gyrA(Ser83 to Leu) and parC (Ser-80 to Phe) genes were commensurate with fluoroquinolone resistance. In addition, the adeA, adeB efflux genes were over-expressed. All 15 isolates were positive for at least two aminoglycoside resistance genes. Conclusion: This is one of the first reports analyzing the multi-drug resistance profile of A. baumannii strains isolated in Bolivia and shows that the over-expression of theblaOXA-58, blaADC and efflux genes together with aminoglycoside modifying enzymes and mutations in DNA topoisomerases are responsible for the multi-resistance of the bacteria and the subsequent difficulty in treating infections caused by them.

scholarly journals Biofilm Formation Caused by Clinical Acinetobacter baumannii Isolates Is Associated with Overexpression of the AdeFGH Efflux Pump

2015 ◽  
Vol 59 (8) ◽  
pp. 4817-4825 ◽  
Author(s):  
Xinlong He ◽  
Feng Lu ◽  
Fenglai Yuan ◽  
Donglin Jiang ◽  
Peng Zhao ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Gene Transcription ◽  
Biofilm Formation ◽  
Efflux Pump ◽  
Outer Membrane Proteins ◽  
Content Type ◽  
Potential Association ◽  
Genes Encoding ◽  
Clinical Environments

ABSTRACTChronic wound infections are associated with biofilm formation, which in turn has been correlated with drug resistance. However, the mechanism by which bacteria form biofilms in clinical environments is not clearly understood. This study was designed to investigate the biofilm formation potency ofAcinetobacter baumanniiand the potential association of biofilm formation with genes encoding efflux pumps, quorum-sensing regulators, and outer membrane proteins. A total of 48 clinically isolatedA. baumanniistrains, identified by enterobacterial repetitive intergenic consensus (ERIC)-PCR as types A-II, A-III, and A-IV, were analyzed. Three representative strains, which were designatedA. baumanniiABR2, ABR11, and ABS17, were used to evaluate antimicrobial susceptibility, biofilm inducibility, and gene transcription (abaI,adeB,adeG,adeJ,carO, andompA). A significant increase in the MICs of different classes of antibiotics was observed in the biofilm cells. The formation of a biofilm was significantly induced in all the representative strains exposed to levofloxacin. The levels of gene transcription varied between bacterial genotypes, antibiotics, and antibiotic concentrations. The upregulation ofadeGcorrelated with biofilm induction. The consistent upregulation ofadeGandabaIwas detected in A-III-typeA. baumanniiin response to levofloxacin and meropenem (1/8 to 1/2× the MIC), conditions which resulted in the greatest extent of biofilm induction. This study demonstrates a potential role of the AdeFGH efflux pump in the synthesis and transport of autoinducer molecules during biofilm formation, suggesting a link between low-dose antimicrobial therapy and a high risk of biofilm infections caused byA. baumannii. This study provides useful information for the development of antibiofilm strategies.

scholarly journals Effects of Hsp90 Inhibitor Ganetespib on Inhibition of Azole-Resistant Candida albicans

2021 ◽  
Vol 12 ◽  
Author(s):  
Rui Yuan ◽  
Jie Tu ◽  
Chunquan Sheng ◽  
Xi Chen ◽  
Na Liu
Keyword(s):  
Drug Resistance ◽  
Candida Albicans ◽  
Biofilm Formation ◽  
Efflux Pump ◽  
Inhibitory Effect ◽  
Hsp90 Inhibitor ◽  
Pcr Analysis ◽  
Fungal Hypha

Candida albicans is the most common fungal pathogen. Recently, drug resistance of C. albicans is increasingly severe. Hsp90 is a promising antifungal target to overcome this problem. To evaluate the effects of Hsp90 inhibitor ganetespib on the inhibition of azole-resistant C. albicans, the microdilution checkerboard method was used to measure the in vitro synergistic efficacy of ganetespib. The XTT/menadione reduction assay, microscopic observation, and Rh6G efflux assay were established to investigate the effects of ganetespib on azole-resistant C. albicans biofilm formation, filamentation, and efflux pump. Real-time RT-PCR analysis was employed to clarify the mechanism of antagonizing drug resistance. The in vivo antifungal efficacy of ganetespib was determined by the infectious model of azole-resistant C. albicans. Ganetespib showed an excellent synergistic antifungal activity in vitro and significantly inhibited the fungal biofilm formation, whereas it had no inhibitory effect on fungal hypha formation. Expression of azole-targeting enzyme gene ERG11 and efflux pump genes CDR1, CDR2, and MDR1 was significantly down-regulated when ganetespib was used in combination with FLC. In a mouse model infected with FLC-resistant C. albicans, the combination of ganetespib and FLC effectively reversed the FLC resistance and significantly decreased the kidney fungal load of mouse.

scholarly journals Cloning, expression, purification and functional analysis of a specific multi-epitope protein from multi drug resistance Acinetobacter baumannii

2021 ◽  
Author(s):  
Zahra Davoudi ◽  
Amirhossein Taromchi ◽  
Bahram Kazemi ◽  
Mojgan Bandehpour ◽  
Nariman Mosaffa
Keyword(s):  
Drug Resistance ◽  
Recombinant Protein ◽  
Acinetobacter Baumannii ◽  
Cloning And Expression ◽  
Multi Drug Resistance ◽  
Expression And Purification ◽  
Bam Complex ◽  
Promising Strategy ◽  
Life Threatening ◽  
Informatics Tools

Background and Objectives: Immunization is a promising strategy to combat against the life-threatening infections by Multi Drug Resistance Acinetobacter baumannii. In this study, we directed to design and evaluate the efficacy of a recombi- nant multi-epitope protein against this pathogen. Materials and Methods: Epitopes prediction was performed for candidate proteins OmpA and BAM complex (BamA, BamB, BamC, BamD, BamE) from A. baumannii, using immune-informatics tools with high affinity for the human HLA alleles. After expression and purification of the recombinant protein, its functional activity was confirmed by interaction with positive sera. Results: Cloning and expression of the desired multi-epitopes protein were verified. Circular Dichroism study showed the secondary structure and proper refolding of the recombinant protein was achieved and matched with computational predic- tion. There was a significant interaction between designed protein with antibodies presented in ICU patients' and staff's sera. Conclusion: The interaction of the recombinant protein with patients' sera antibodies suggests that it may be a promising determinant protein for immunization against of MDR A. baumannii.

scholarly journals EVALUATION OF EFFLUX PUMP ACTIVITY AND BIOFILM FORMATION IN MULTIDRUG RESISTANT KLEBSIELLA PNEUMONIAE ISOLATES IN TANTA, EGYPT

2021 ◽  
Vol 12 (3) ◽  
pp. 1-5
Author(s):  
Tarek El-Said El-Banna ◽  
Fatma Ibrahim Sonbol ◽  
Heba M El-Dawy ◽  
Lamiaa A Al-Madboly
Keyword(s):  
Drug Resistance ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Efflux Pump ◽  
Treatment Options ◽  
Multidrug Resistant ◽  
High Morbidity ◽  
Biochemical Tests ◽  
Antibiotic Resistance Profile ◽  
Pump Activity

Nosocomial and community acquired infections that caused by multidrug-resistant (MDR) Klebsiella pneumoniae isolates are widespread recently resulting in high morbidity and mortality due to limited number of treatment options with effective antibiotics. The aim of this study is to evaluate the antibiotic resistance profile, biofilm formation and efflux pump activity of MDR K. pneumoniae isolates collected from different hospitals in Tanta, Egypt. A total of 70 K. pneumoniae isolates characterized by standard biochemical tests and confirmed by MALDI-TOF/MS were screened for antibiotic susceptibility, efflux pump activity and biofilm formation. Isolates displayed high resistance to penicillins, cephalosporins, trimethoprim-sulfamethoxazole and the majority of tested fluoro/-quinolones and decreased resistance to imipenem, amikacin, chloramphenicol, tigecycline and colistin. Out of 70 K. pneumoniae isolates, 2 isolates exhibited Pan Drug-Resistance (PDR) profile while 57 (81.4%) and 11 (15.7%) exhibited MDR and Extensively drug-resistance (XDR) profiles, respectively. Sixty-four (91.4%) isolates exhibited efflux pump activity while all tested isolates had the ability to form biofilm with varied degrees as 40 (57.1%), 26 (37.1%), and 4 (5.7%) isolates were strong, moderate and weak biofilm producers, respectively. Also, a strong relation between efflux pump activity and biofilm formation per isolate was detected. In conclusion, Multidrug resistance, biofilm formation and efflux pump capabilities in K. pneumoniae have serious public health implications in the management and control of infections caused by this bacterium. Therefore, a multifaceted approach and precise planning are recommended in controlling these infections

scholarly journals To determine antimicrobial susceptibility and biofilm production among coagulase negative staphylococci at a tertiary care hospital

2021 ◽  
Vol 8 (3) ◽  
pp. 230-234
Author(s):  
Naga Sri Latha Bathala ◽  
M Sasidhar ◽  
S Kusuma Bai
Keyword(s):  
Drug Resistance ◽  
Antimicrobial Susceptibility ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Tertiary Care ◽  
Multi Drug Resistance ◽  
Clinical Samples ◽  
Care Hospital ◽  
Coagulase Negative Staphylococci ◽  
Cross Sectional

CoNS are gaining importance due to increase in resistance rates to betalactam antibiotics and multi drug resistance. Although specific virulence factors are not as clearly established, it seems clear that factors such as bacterial polysaccharide components, and ability to form biofilm are involved in attachment and/or persistence of bacteria on foreign materials. Biofilms usually result in persistent infections that cannot be easily resolved with standard antibiotic treatments; therefore, the biofilm formation ability and the resistance to antimicrobial therapy can be intimately related. A prospective cross-sectional study was done on purely isolated CoNS from various clinical samples from both out patients and inpatients. All the test strains were subjected to antimicrobial susceptibility testing. The ability to produce biofilm was detected by tube adherence method. Among 193 CoNS isolates 156 were from inpatients and 37 were from out patients. Methicillin resistant was seen in 80.31%. Of the total, 40.41% showed moderate biofilm formation by tube adherence method. 23.32% of isolates did not form biofilm. All the isolates from blood samples showed moderate (20/26) and strong (6/26) biofilm formation. Among non biofilm producers 66.67% were MS CoNS isolates and 33.33% were MRCoNS. 94.59% of biofilm producers were MRCoNS and 5.41% were MSCoNS. Production of biofilm was relatively more (1.16) among CoNS isolates of IPD than OPD.  As Coagulase negative Staphylocooci are exhibiting multi drug resistance and are able to form biofilm, these organisms causing a major challenge for the physicians. Hence, such problems can be prevented by detection of biofilm producers and appropriate antibiotic doses modification. The issue of antibiotic resistance among CoNS needs to be addressed through a more rational use of existing antibiotics as well as the development of new antimicrobial agents.

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