Effect of RecA inactivation on quinolone susceptibility and the evolution of resistance in clinical isolates of Escherichia coli

2020 ◽  
Author(s):  
J Machuca ◽  
E Recacha ◽  
B Gallego-Mesa ◽  
S Diaz-Diaz ◽  
G Rojas-Granado ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Risk ◽  
Growth Curves ◽  
Sos Response ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Mutant Prevention Concentration ◽  
The Impact ◽  
Mutant Frequency ◽  
St131 Clone

Abstract Background SOS response suppression (by RecA inactivation) has been postulated as a therapeutic strategy for potentiating antimicrobials against Enterobacterales. Objectives To evaluate the impact of RecA inactivation on the reversion and evolution of quinolone resistance using a collection of Escherichia coli clinical isolates. Methods Twenty-three E. coli clinical isolates, including isolates belonging to the high-risk clone ST131, were included. SOS response was suppressed by recA inactivation. Susceptibility to fluoroquinolones was determined by broth microdilution, growth curves and killing curves. Evolution of quinolone resistance was evaluated by mutant frequency and mutant prevention concentration (MPC). Results RecA inactivation resulted in 2–16-fold reductions in fluoroquinolone MICs and modified EUCAST clinical category for several isolates, including ST131 clone isolates. Growth curves and time–kill curves showed a clear disadvantage (up to 10 log10 cfu/mL after 24 h) for survival in strains with an inactivated SOS system. For recA-deficient mutants, MPC values decreased 4–8-fold, with values below the maximum serum concentration of ciprofloxacin. RecA inactivation led to a decrease in mutant frequency (≥103-fold) compared with isolates with unmodified SOS responses at ciprofloxacin concentrations of 4×MIC and 1 mg/L. These effects were also observed in ST131 clone isolates. Conclusions While RecA inactivation does not reverse existing resistance, it is a promising strategy for increasing the effectiveness of fluoroquinolones against susceptible clinical isolates, including high-risk clone isolates.

scholarly journals Role of low-level quinolone resistance in generating tolerance in Escherichia coli under therapeutic concentrations of ciprofloxacin

2020 ◽  
Author(s):  
M Ortiz-Padilla ◽  
S Diaz-Diaz ◽  
J Machuca ◽  
A Tejada-Gonzalez ◽  
E Recacha ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sos Response ◽  
Resistance Mechanisms ◽  
Quinolone Resistance ◽  
Response Suppression ◽  
Bacterial Survival ◽  
Resistance Mutations ◽  
Low Level ◽  
Short Period ◽  
The Impact

Abstract Background Tolerance (including persistence) and resistance result in increased survival under antibiotic pressure. Objectives We evaluated the interplay between resistance and tolerance to ciprofloxacin under therapeutic and killing conditions to determine the contribution of low-level quinolone resistance (LLQR) mechanisms to tolerance. We also determined how the interaction between resistance (LLQR phenotypes) and tolerance was modified under SOS response suppression. Methods Twelve isogenic Escherichia coli strains harbouring quinolone resistance mechanisms combined with SOS response deficiency and six clinical E. coli isolates (LLQR or non-LLQR) were evaluated. Survival (tolerance or persistence) assays were used to measure surviving bacteria after a short period (up to 4 h) of bactericidal antibiotic treatment under therapeutic and killing concentrations of ciprofloxacin [1 mg/L, EUCAST/CLSI breakpoint for resistance; and 2.5 mg/L, peak serum concentration (Cmax) of this drug]. Results QRDR substitutions (S83L in GyrA alone or combined with S80R in ParC) significantly increased the fraction of tolerant bacteria (2–4 log10 cfu/mL) after exposure to ciprofloxacin at clinically relevant concentrations. The impact on tolerant bacteria due to SOS response suppression (including persistence mediated by the tisB gene) was reversed by LLQR mechanisms at therapeutic concentrations. Furthermore, no reduction in the fraction of tolerant bacteria due to SOS response suppression was observed when S83L in GyrA plus S80R in ParC were combined. Conclusions Tolerance and quinolone resistance mutations interact synergistically, giving LLQR mechanisms an additional role in allowing bacterial survival and evasion of therapeutic antimicrobial conditions by a combination of the two strategies. At clinically relevant concentrations, LLQR mechanisms reverse further impact of SOS response suppression in reducing bacterial tolerance.

scholarly journals Interplay between IncF plasmids and topoisomerase mutations conferring quinolone resistance in the Escherichia coli ST131 clone: stability and resistance evolution

2021 ◽  
Author(s):  
Jose-Manuel Rodríguez-Martínez ◽  
Lorena Lopez-Cerero ◽  
Ana García-Duque ◽  
Jesus Rodriguez-Baño ◽  
Alvaro Pascual
Keyword(s):  
Escherichia Coli ◽  
Plasmid Stability ◽  
Luria Broth ◽  
Quinolone Resistance ◽  
Experimental Conditions ◽  
E Coli ◽  
The Stability ◽  
The Impact ◽  
Mutant Frequency

Abstract The Escherichia coli ST131 H30-Rx subclone vehicles CTX-M-15 plasmids and mutations in gyrA and parC conferring multidrug resistance successfully in the clinical setting. The aim of this study was (1) to investigate the relationship of specific topoisomerase mutations on the stability of IncF (CTX-M producing) plasmids using isogenic E. coli mutants and (2) to investigate the impact of the IncF-type plasmids present in the E. coli clone ST131 on the evolution of quinolone resistance. E. coli ATCC 25922 (background strain) and derived mutants encoding specific QRDR substitutions were used. Also, NGS-characterized IncFIA and IncFIB plasmids (encoding CTX-M genes) were included. Plasmid stability was evaluated by sequential dilutions into Luria broth medium without antibiotics for 7 days. Mutant frequency to ciprofloxacin was also evaluated. Moderate differences in the IncF plasmids stability were observed among E. coli ATCC 25922 and isogenic mutants. Under our experimental conditions, the fluctuation of bacteria harboring plasmids was less than 0.5-log(10) in all cases. In the mutant frequency tests, it was observed that the presence of these IncF plasmids increased this value significantly (10–1000-fold). Quinolone resistance substitutions in gyrA or parC genes, frequently found associated with E. coli clone ST131, do not modify the stability of ST131-associated IncFIA and IncFIB plasmids under in vitro conditions. IncF-type plasmids present in E. coli clone ST131 facilitate the selection of resistance to quinolones. These results are consistent with the clinical scenario in which the combination of resistance to quinolones and beta-lactams is highly frequent in the E. coli clone ST131.

Investigation of High-Risk ST131 Clone in Extended Spectrum β-Lactamase–Producing Escherichia coli Isolates in Children

2021 ◽  
Author(s):  
Mehmet E. Bulut ◽  
Gülen Hürkal ◽  
Nazan Dalgıç
Keyword(s):  
Escherichia Coli ◽  
High Risk ◽  
Pediatric Patients ◽  
Pediatric Population ◽  
Maldi Tof Ms ◽  
E Coli ◽  
Maldi Tof ◽  
Extended Spectrum ◽  
St131 Clone ◽  
Tof Ms

Abstract Objective Antimicrobial resistance poses a serious threat to children's health. In recent years, high-risk Escherichia coli ST131 has become an important target for global surveillance studies. The E.coli ST131 clone is associated with extended spectrum β-lactamase (ESBL) production, as well as multidrug resistance and treatment failure. Studies on this clone in the pediatric age group are limited. We aim to investigate the rate of high-risk E. coli ST131 clone in ESBL-positive E. coli isolates obtained from pediatric patients. Methods A total of 292 ESBL-positive E. coli isolates from clinical samples of pediatric patients was included in the study. MALDI-TOF MS system was used for bacterial identification. Susceptibility tests were performed using BD Phoenix automated system. ST131 detection was done by MALDI-TOF-MS. Fisher's exact test was used to compare the groups (significance <0.05). Results A total of 292 isolates was analyzed. The high-risk ST131 clone was detected in 117 (40%) of the 292 ESBL-positive isolates. ST131 rates were found to be significantly higher in children under the age of 5 years compared with children over the age of 5 years (49.3 vs. 31.1%, p = 0.0019). Ciprofloxacin resistance was higher in ST131 isolates (45.6 vs. 31.7%; p < 0.05). Conclusion The rate of the ST131 clone was found to be high in the pediatric population. The significantly high rate of resistance to ciprofloxacin, which is not commonly used in the pediatric population, in ST131 isolates reveals the importance of the spread of high-risk clones for the development of resistance.

scholarly journals EVALUATION OF THE IMPACT OF PLASMID CURING ON ANTIBIOTIC RESISTANCE ON SOME CLINICAL ISOLATES OF ESCHERICHIA COLI

2020 ◽  
Vol 4 (3) ◽  
pp. 323-327
Author(s):  
Mamunu Abdulkadir SULAIMAN ◽  
H.S Muhammad ◽  
Aliyu Muhammad Sani ◽  
Aminu Ibrahim ◽  
Ibrahim Muhammad Hussain ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Plasmid Curing ◽  
Sensitivity Testing ◽  
E Coli ◽  
Risk Of Death ◽  
Mar Index ◽  
The Impact

Multidrug resistance (MDR) exhibited by some strains of Escherichia coli may be due to acquiring mobile genetic element (R-plasmid) by the bacteria, or intrinsically induced by inappropriate use of antibiotics by the hosts.  Infection by such strains may result to prolonged illness and greater risk of death. The study evaluated the impact of curing on antibiotic resistance on selected clinical isolates of E. coli. Twenty clinical isolates of E. coli from our previous studies were re-characterized using conventional microbiological techniques. Antibiotic sensitivity testing was determined by disk diffusion method, MDR selected based on resistance to ≥ 2 classes of antibiotics. Multiple antibiotic resistance (MAR) index was determined as ratio of the number of antibiotic resisted to the total number of antibiotics tested and considered significant if ≥. 0.2. The isolates that showed significant MAR index were subjected to plasmid curing using acridine orange, thereafter, profiled for plasmid and the cured ones were re-tested against the antibiotics they initially resisted. Out of the 20 isolates, 19 (95%) were confirmed as E. coli, all (100%) of which were MDRs, which was highest against augmentin (78.9%) followed by amoxacillin (52.6%). However, after the plasmid curing only 6 (31.6%) out of the 19 isolates cured retained significant MAR index and the level of the significance had reduced drastically in 16 (84.2%) isolates. Conclusively, curing assay can completely eliminate R-plasmid acquired resistance. More studied on plasmid curing agents for possible augmentation of the agents into antibiotics may see the rise of successful antibiotic era again.

Prevalence of plasmid-mediated quinolone resistance qnr genes in poultry and swine clinical isolates of Escherichia coli

2008 ◽  
Vol 132 (3-4) ◽  
pp. 414-420 ◽  
Author(s):  
Lei Yue ◽  
Hong-Xia Jiang ◽  
Xiao-Ping Liao ◽  
Jian-Hua Liu ◽  
Shu-Juan Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quinolone Resistance ◽  
Clinical Isolates

scholarly journals Comparative Analysis of Quinolone Resistance in Clinical Isolates ofKlebsiella pneumoniaeandEscherichia colifrom Chinese Children and Adults

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Ying Huang ◽  
James O. Ogutu ◽  
Jiarui Gu ◽  
Fengshu Ding ◽  
Yuhong You ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Environmental Issues ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Chinese Adults ◽  
Double Mutation ◽  
History Of ◽  
Ciprofloxacin Resistance ◽  
Resistance Rates

The objective of this study was to compare quinolone resistance andgyrAmutations in clinical isolates ofKlebsiella pneumoniaeandEscherichia colifrom Chinese adults who used quinolone in the preceding month and children without any known history of quinolone administration. The antimicrobial susceptibilities of 61 isolates from children and 79 isolates from adults were determined. The mutations in the quinolone resistance-determining regions ingyrAgene were detected by PCR and DNA sequencing. Fluoroquinolone resistance and types ofgyrAmutations in isolates from children and adults were compared and statistically analyzed. No significant differences were detected in the resistance rates of ciprofloxacin and levofloxacin between children and adults among isolates of the two species (allP>0.05). The double mutation Ser83→Leu + Asp87→Asn in the ciprofloxacin-resistant isolates occurred in 73.7% isolates from the children and 67.9% from the adults, respectively (P=0.5444). Children with no known history of quinolone administration were found to carry fluoroquinolone-resistantEnterobacteriaceaeisolates. The occurrence of ciprofloxacin resistance and the major types ofgyrAmutations in the isolates from the children were similar to those from adults. The results indicate that precautions should be taken on environmental issues resulting from widespread transmission of quinolone resistance.

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