Microbial drug resistance最新文献

Multidrug-resistant Neisseria gonorrhoeae is a serious concern worldwide. Resistance to β-lactam antibiotics occurs through mutations in penicillin-binding proteins (PBPs), acquisition of β-lactamases, and alteration of antibiotic penetration. Mosaic structures of penA, which encodes PBP2, play a major role in resistance to β-lactams, especially cephalosporins. Ceftriaxone (CRO) is recognized as the only satisfiable antibiotic for the treatment of gonococcal infections; however, CRO-resistant isolates have emerged in the community. Here, we examined the affinity of β-lactam antibiotics for recombinant PBP2 in a competition assay using fluorescence-labeled penicillin. We found no or little difference in the affinities of penicillins and meropenem (MEM) for PBP2 from cefixime (CFM)-reduced-susceptible strain and cephalosporin-resistant strain. However, the affinity of cephalosporins, including CRO, for PBP2 from the cephalosporin-resistant strain was markedly lower than that for PBP2 from the CFM-reduced-susceptible-resistant strain. Notably, piperacillin (PIP) showed almost the same affinity for PBP2 from penicillin-susceptible, CFM-reduced-susceptible, and cephalosporin (including CRO)-resistant strains. Thus, PIP/tazobactam and MEM are candidate antibiotics for the treatment of CRO-resistant/multidrug-resistant N. gonorrhoeae.

Klebsiella pneumoniae is one of the main opportunistic pathogens that cause a broad spectrum of diseases with increasingly frequent acquisition of resistance to antibiotics, namely carbapenems. This study focused on the characterization of 23 OXA-48-like carbapenemase-producing K. pneumoniae isolates using phenotypic and molecular tests. Phenotypic determination of the presence of β-lactamases was performed using the extended-spectrum beta-lactamase (ESBL) NP test, and phenotypic determination of the presence of carbapenemase was based on the Carba NP test. Antimicrobial susceptibility tests were performed to assess the resistance against carbapenems. Molecular characterization of ESBL genes and carbapenemase genes (bla_OXA-48, bla_KPC, bla_VIM, and bla_NDM) was performed using polymerase chain reaction (PCR) techniques. In addition, K. pneumoniae strains were analyzed for their relatedness using multilocus sequence typing PCR analysis based on the Institut Pasteur protocol, which produces allelic profiles that contain their evolutionary and geographic pattern. Following further Sanger sequencing of the bla_OXA-48 genes, no genetic mutations were found. Some OXA-48-producing K. pneumoniae isolates coharbored bla_KPC, bla_NDM, and bla_VIM genes, which encode other carbapenemases that can hydrolyze carbapenem antibiotics. The final part of the study focused on the characterization of the plasmid profiles of all isolates to better understand the spreading of the IncL/M bla_OXA-48 plasmid gene. The plasmid profile also revealed other incompatibility groups, suggesting that other plasmid genes are spreading in K. pneumoniae isolates, which can coharbor and spread different carbapenemases simultaneously.

The emergence of multidrug-resistant Pseudomonas aeruginosa possesses a significant public health concern. Constitutively expressed MexAB-OprM efflux pumps in P. aeruginosa significantly contribute to its resistance to a variety of antibiotics. The development of efflux pump inhibitors (EPIs) has emerged as an attractive strategy in reversing antibiotic resistance. In this study, structure-based virtual screening techniques were used for the identification of new MexAB-OprM efflux inhibitors. The predicted poses were thoroughly filtered by induced fit docking procedures followed by in vitro microbiological assays for the validation of in silico results. Two compounds, NSC-147850 and NSC-112703, were able to restore tetracycline susceptibility in MexAB-OprM overexpressing Pseudomonas aeruginosa ATCC^® 27853™ strain. This correlation observed between in silico screening and positive efflux inhibitory activity in vitro suggests that NSC-147850 and NSC-112703 have potential as EPIs and may be effective in combination therapy against drug-resistant strains of P. aeruginosa.

Resistance to last resort antibiotics has been increasing, particularly in low- and middle-income countries such as Lebanon, which has well established challenges in antimicrobial stewardship and other public health and environmental issues. However, data on the emergence of antibiotic resistance in the community in Lebanon are limited. In this study, we assessed resistance to last resort antibiotics in the fecal samples of 111 otherwise healthy university students in north Lebanon. The results showed that 47.7% of the samples harbored extended-spectrum cephalosporin-resistant isolates, while 2.7% of the samples yielded colistin-resistant isolates. Furthermore, molecular analyses showed that the β-lactamase gene group, bla_CTX-M-1 group, was detected in the majority (93%) of screened extended-spectrum β-lactamase isolates. In addition, the colistin-resistant Escherichia coli isolates carried mcr-1, including the novel mcr-1.26 variant, which was previously reported in clinical samples as well as in domesticated animals and the environment in Lebanon. Taken together, these findings highlight the occurrence of resistance to important antibiotics in the community, perhaps suggesting diffuse sources, including clinical and environmental settings, and multiple factors driving the spread of multidrug-resistant bacteria and resistance determinants. There is a pressing need for comprehensive antimicrobial stewardship programs and the implementation of evidence-based practices in clinical and community settings to mitigate the increasing spread of antimicrobial resistance.

Multidrug-resistant Escherichia coli, particularly carbapenemase producers, are a major source of concern. This study aims to investigate the long-term epidemiology of Verona integron-encoded metallo-β-lactamase (VIM)-producing E. coli in the health district of Bolzano, Northern Italy, by examining the phenotypic and genotypic characteristics of 26 isolates obtained during 2005-2020. Isolates were identified with matrix-assisted laser desorption/ionization time-of-flight, susceptibility testing was by Vitek 2, Sensititre, and Etest; carbapenemase activity was confirmed by Etest and Carbapenemase Inactivation Method (CIM) test; and the VIM-antigen was identified by the NG-Test CARBA 5. Genome sequencing was performed on an Illumina MiSeq platform. Carbapenem minimum inhibitory concentrations varied across methodologies, and overall category agreement between phenotypic methods was low. All 23 sequenced isolates contained bla_VIM-1. Eleven (47.8%) isolates belonged to the clonal lineage ST131, with fimH30 being the most common subclone. In Bolzano ST131-fimH30 was present as early as 2005. While the ST131 clonal lineage predominated for the first 10 years, various clonal lineages were present, especially in subsequent years, indicating the concurrent circulation of multiple clonal lineages. Future efforts should focus on the implementation of surveillance methods, including genomic analysis, as well as the use of updated infection control strategies and antibiotic stewardship programs to prevent the spread of these carbapenem-resistant strains.

Staphylococcus aureus is a major, widespread pathogen, and its biofilm-forming characteristics make it even more difficult to eliminate by biocides. Tetracycline (TCY) is a major broad-spectrum antibiotic, the residues of which can cause deleterious health impacts, and subinhibitory concentrations of TCY have the potential to increase biofilm formation in S. aureus. In this study, we showed how the biofilm formation of S. aureus 123786 is enhanced in the presence of TCY at specific subinhibitory concentrations. S. aureus 123786 used in this study was identified as Staphylococcal Cassette Chromosome mec III, sequence type239 and naturally lacking ica operon and atl gene. Two assays were performed to quantify the formation of S. aureus biofilm. In the crystal violet (CV) assay, the absorbance values of biofilm stained with CV at optical density (OD)540 nm increased after 8 and 16 hr of incubation when the concentration of TCY was 1/2 minimum inhibitory concentration (MIC), whereas at the concentration of 1/16 MIC, the absorbance values increased after 16 and 24 hr of incubation. In tetrazolium salt reduction assay, the absorbance value at OD490 nm of S. aureus 123786 biofilms mixed with 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium solution increased after 8 hr when the concentration of TCY was 1/4 MIC, which may be correlated with the higher proliferation and maturation of biofilm. In conclusion, the biofilm formation of S. aureus 123786 could be enhanced in the presence of TCY at specific subinhibitory concentrations.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major infectious disease pathogen, and its molecular epidemiological profile has been changing. In this study, a total of 279 MRSA isolates were collected from patients with bloodstream infection (BSI) in Hokkaido, northern main island of Japan, for a 2-year period from August 2019 to July 2021. CC5 (ST5/ST764)-MRSA-IIa (SCCmec-IIa) (47%, n = 132) and CC1 (ST1/ST2725/ST2764)-MRSA-IVa (42%, n = 116) were found to be major lineages, with CC8-MRSA-IVa being lower prevalence (5%, n = 13). CC1-MRSA-IVa showed a relatively increased proportion compared with our previous study (22%, 2017-2019). Seven isolates with SCCmec IVa (2.5%) were positive for Panton-Valentine leukocidin genes on ΦSa2usa and belonged to ST8/spa-t008/agr-I/coa-IIIa, showing genetic features of the USA300 clone. Among these isolates, six isolates harbored arginine catabolic mobile element (ACME) type I typical to the USA300 clone, while it was not detected in an isolate (strain R3-8). Whole genomic analysis of strain R3-8 revealed that its chromosome was highly similar to the USA300 strain TCH1516, but lacked ACME, carrying a plasmid genetically close to that of USA300 strains. The present study revealed increasing trend of CC1-MRSA-IV and occurrence of a novel variant of the USA300 clone among MRSA from BSI in northern Japan.

Antimicrobial resistance (AMR) is a global health threat requiring urgent attention and effective strategies for containment. AMR is fueled by wastewater mismanagement and global mobility, disseminating multidrug-resistant (MDR) strains worldwide. While global estimates of AMR burden have been informative, community-level understanding has received little attention despite reports of high AMR prevalence in healthy communities. We assessed the "invasion" of antibiotic resistance genes (ARGs) into the normal human flora by characterizing AMR Escherichia coli in local wastewaters contributed by a healthy youth population. This study estimated 26% (out of 300 isolates) resistant and 59% plasmid-bearing E. coli in local wastewater. Of the 78 AMR isolates, the frequency of mono-resistance was higher against tetracycline (32%), followed by kanamycin (17%) and chloramphenicol (9%). Five isolates were potentially MDR. We further sequenced four MDRs and four sensitive strains to comprehend the genome and resistome diversity in comparison to the global wastewater E. coli (genomes from the PATRIC database). The whole-genome analysis revealed extensive genome similarity among global isolates, suggesting global dissemination and colonization of E. coli. Global wastewater resistome majorly comprised ARGs against aminoglycosides (26%), beta-lactam (17%), sulfonamide (11%), and trimethoprim (8%). Resistance to colistin, a last-resort antibiotic, was prevalent in MDRs of European and South Asian isolates. A systems approach is required to address the AMR crisis on a global scale, reduce antibiotic usage, and increase the efficiency of wastewater management and disinfection.

Candida auris is a concerning pathogen in health care due to its ability to spread in medical settings. In this study, we characterized the genome of three C. auris clinical isolates collected in the Emilia-Romagna region of Northeastern Italy from January 2020 to May 2021. Whole-genome sequencing was performed using Illumina iSeq 100 and Oxford Nanopore MinION systems. Genomes were assembled with Flye. Phylogenetic analysis was carried out with RaxML. The ERG11, TAC1b, and FKS1 genes were examined for known substitutions associated with resistance to azoles and caspofungin using Diamond. All three C. auris isolates belonged to clade I (South Asian lineage) and showed high minimum inhibitory concentrations for fluconazole. Two of the three isolates were closely related to the first Italian index case of C. auris occurred in the 2019 and carried similar mutations associated to azole resistance. The third isolate showed a greater phylogenetic distance from these strains and had a different genetic determinant not previously seen in Italy. Our data suggest that two C. auris clinical isolates may have been epidemiologically related to the first outbreak previously observed in Italy, while the remaining isolate may have originated from a different source. Further research is needed to understand C. auris transmission and resistance and to control its spread.

The present work deals with the analysis and monitoring of bacterial resistance in using Python for the state of Gujarat, India, where occurrences of drug-resistant bacteria are prevalent. This will provide an insight into the portfolio of drug-resistant bacteria reported, which can be used to track resistance behavior and to suggest a treatment regime for the particular bacteria. The present analysis has been done using Python on Jupyter Notebook as the integrated development environment and its data analysis libraries such as Pandas, Seaborn, and Matplotlib. The data have been loaded from excel file using Pandas and cleaned to transform features into required format. Seaborn and Matplotlib have been used to create data visualizations and represent the data inexplicable manner using graphs, plots, and tables. This program can be used to study disaster epidemiology, tracking, analyzing, and surveillance of antimicrobial resistance with a proper system integration approach.