Staphylococcus aureus is one of the most common bacterial pathogens, often asymptomatically colonizing healthy people, but capable of causing fatal disease. The ability to treat S. aureus infections is limited by the rapid spread of multidrug-resistant strains. This study aimed to determine the prevalence of S. aureus carriage among students from Okada, Edo State, Nigeria, to analyze the antibiotic resistance patterns and molecular characteristics of S. aureus isolates. One hundred healthy students from Okada, Nigeria, were tested for nasal colonization by S. aureus. Isolates were identified using standard microbiological methods. The susceptibilities of the isolates to a panel of 22 antimicrobials were tested. spa and staphylococcal cassette chromosome mec typing were performed. The prevalence of S. aureus and methicillin-resistant S. aureus (MRSA) among the students was 23% and 6%, respectively. Of the six (26.1%; 6/23) MRSA isolates detected, CC88-MRSA-IVa (n = 2) and CC7-MRSA-V (n = 2) were the most frequent clones. The CC7-MRSA-V isolates were resistant to multiple antimicrobials. Overall, resistance to beta-lactams, tetracyclines, fluoroquinolones, and aminoglycosides was detected among the S. aureus and MRSA isolates. The high prevalence of MRSA and methicillin-susceptible isolates with resistance to multiple antimicrobial classes observed among the students is an alarming finding. This study indicated the circulation of resistant clones of S. aureus in Nigerian educational institutions and the community.
- MeSH
- antibakteriální látky farmakologie MeSH
- lidé MeSH
- methicilin rezistentní Staphylococcus aureus * MeSH
- mikrobiální testy citlivosti MeSH
- rezistence na methicilin MeSH
- stafylokokové infekce * farmakoterapie epidemiologie mikrobiologie MeSH
- Staphylococcus aureus MeSH
- studenti MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Nigérie MeSH
The objective of this study was to assess the susceptibility of cefiderocol against multidrug-resistant carbapenemase-producing and nonproducing bacteria. The panel comprised 182 isolates of the order Enterobacterales, and 40 strains of Pseudomonas aeruginosa. Antimicrobial susceptibility testing has been performed using broth microdilution method according to the European Committee on Antimicrobial Susceptibility Testing recommendations. Mass spectrometry matrix-assisted laser desorption/ionization-time of flight mass spectrometry and carbapenemase-producing test were used to verify the presence of carbapenemases in clinical isolates. The genetic expression of single carbapenemases (blaKPC, blaOXA-48, blaNDM, blaVIM, blaIMP, blaGES) was determined by real-time polymerase chain reaction. Cefiderocol exhibited a good activity against the majority of strains tested in this study. Altogether, growth of 81.9% (n = 149) strains of the order Enterobacterales and 77.5% (n = 31) of P. aeruginosa isolates were inhibited at minimal inhibitory concentration (MIC) ≤2 mg/L. Values MIC50/MIC90 were 0.5/8 mg/L for enterobacteria, and 1/8 mg/L for P. aeruginosa. One isolate (Klebsiella pneumoniae) harboring two carbapenemases (blaOXA-48, blaNDM) had cefiderocol MIC 0.5 mg/L. In enterobacteria resistant to cefiderocol, blaNDM carbapenemase prevailed (43.3%, n = 29), followed by blaOXA-48 (31.3%, n = 21) and blaKPC (4.5%, n = 3). blaIMP (n = 8) and blaVIM (n = 1) metallo-β-lactamases dominated in cefiderocol-resistant P. aeruginosa (n = 9) isolates. Very good susceptibility (100%) to this drug showed blaGES-positive strains of P. aeruginosa (n = 8) and isolates resistant to meropenem without confirmed carbapenemase gene (n = 10). In this study, cefiderocol demonstrated potent activity against important nosocomial pathogens, therefore, therapeutic options of this drug against multidrug-resistant bacteria should be considered.
- MeSH
- antibakteriální látky farmakologie MeSH
- antiinfekční látky * MeSH
- bakteriální geny MeSH
- lidé MeSH
- methicilin rezistentní Staphylococcus aureus * genetika MeSH
- mikrobiální testy citlivosti MeSH
- rezistence na methicilin genetika MeSH
- stafylokokové infekce * genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- dopisy MeSH
Oxacillinases (OXA) have been mostly described in Enterobacteriaceae, Acinetobacter, and Pseudomonas species. Recent years have witnessed an increased prevalence of intrinsic and/or acquired β-lactamase-producing Acinetobacter in food-producing animals. This study was conducted to assess the prevalence of OXA among selected bacterial species and to characterize these enzymes by in silico analysis. Screening of OXA was performed by PCR amplification using specific pairs of oligonucleotides. Overall, 40 pairs of primers were designed, of which 6 were experimentally tested in vitro. Among 49 bacterial isolates examined, the presence of blaOXA-1-like genes was confirmed in 20 cases (41%; 19 times in Klebsiella pneumoniae and once in Enterobacter cloacae). No OXA were found in animal isolates. The study results confirmed the specificity of the designed oligonucleotide pairs. Furthermore, the designed primers were found to possess the ability to specifically detect 90.2% of all OXA. These facts suggest that the in silico and in vitro tested primers could be used for single or multiplex PCR to screen for the presence of OXA in various bacteria, as well as to monitor their spread. At the same time, the presence of conserved characteristic amino acids and motifs was confirmed by in silico analysis of sequences of representative members of OXA.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální proteiny genetika metabolismus MeSH
- beta-laktamasy genetika metabolismus MeSH
- DNA primery chemická syntéza metabolismus MeSH
- Enterobacter cloacae klasifikace účinky léků enzymologie genetika MeSH
- Escherichia coli klasifikace účinky léků enzymologie genetika MeSH
- exprese genu MeSH
- fylogeneze MeSH
- gramnegativní bakteriální infekce diagnóza epidemiologie mikrobiologie veterinární MeSH
- Klebsiella pneumoniae klasifikace účinky léků enzymologie genetika MeSH
- kur domácí mikrobiologie MeSH
- lidé MeSH
- maso mikrobiologie MeSH
- mikrobiální testy citlivosti MeSH
- multiplexová polymerázová řetězová reakce metody MeSH
- peniciliny farmakologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
The aim of this study was to detect and characterize isolates of methicillin-/oxacillin-resistant Staphylococcus aureus (MRSA) carrying gene mecC (MRSA/mecC) and occurring in the Czech Republic within the period from 2002 to 2017. Altogether, 18 from 3,472 isolates of MRSA were mecC positive (0.52%). The first detection of MRSA/mecC in the Czech Republic is dated to 2004. MRSA/mecC isolates were susceptible to almost all tested antibiotics with few exceptions. Resistances to erythromycin (n = 2), clindamycin (n = 1), trimethoprim-sulfamethoxazole (n = 1), and rifampicin (n = 1) were found in the collection. Multilocus sequence typing and spa typing revealed a genetic heterogeneity of MRSA/mecC strains: three CCs (130, 425, and 2361), five STs (1245, 130, 2361, 425, and a new ST5480), and eight spa types (t843, t978, t1048, t1535, t1736, t6104, t8842, and t17153), which were detected in the study, with the highest prevalence of CC130/t843 lineage (n = 8, 44%). Except for two strains, none from 18 examined isolates harbored genes encoding any of S. aureus toxins: enterotoxins a-u, exfoliative toxins A, B, and D, toxic shock syndrome toxin-1, and the Panton-Valentine leukocidin.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální geny genetika MeSH
- genotyp MeSH
- methicilin rezistentní Staphylococcus aureus genetika MeSH
- mikrobiální testy citlivosti MeSH
- multilokusová sekvenční typizace MeSH
- oxacilin farmakologie MeSH
- polymerázová řetězová reakce MeSH
- proteiny vázající penicilin metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
The aim of the present study was to determine the rate and mechanisms of resistance to macrolides, lincosamides, and streptogramin B (MLSB) antibiotics of Staphylococcus aureus collected in Central Greece. Of the 2,893 S. aureus collected during 2012-2017, 1,161 isolates (40.2%) exhibited resistance to at least one of the MLSB agents. The rate of erythromycin resistance was statistically significantly higher in methicillin-resistant S. aureus (MRSA) (58.6%) than in methicillin-sensitive S. aureus (MSSA) isolates (20.7%) (p = 0.002). Two hundred seventy-five representative MLSB-resistant S. aureus, including 81 MSSA and 194 MRSA isolates, were further studied. Thirty-eight MSSA isolates carried ermC, 26 MSSA were positive for ermA, whereas 17 isolates carried msrA gene. Among MRSA, the ermA gene was identified in the majority of the isolates (n = 153). Thirty-seven MRSA isolates carried ermC; three isolates carried msrA, whereas the remaining MRSA was positive for two genes (ermA and ermC). Phylogenetic analysis showed that ST225, which belongs to CC5, was the most prevalent, accounting for 137 MRSA isolates. Higher genetic diversity was found in the group of MSSA isolates, which comprised of 13 sequence types. Whole-genome sequencing data showed that all ermA-positive S. aureus, with the exception of one ST398 isolate, harbored the ermA-carrying Tn554 transposon integrated into their chromosomes. Furthermore, Illumina sequencing followed by polymerase chain reaction screening identified that ermC, which was identified in a polyclonal population of MSSA and MRSA isolates, was carried by small plasmids, like pNE131. These findings highlighted the important role of high-risk clones and of mobile elements carrying resistance genes in the successful dissemination of MLSB-resistant staphylococci.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální proteiny genetika MeSH
- fylogeneze MeSH
- genotyp MeSH
- lidé MeSH
- linkosamidy farmakologie MeSH
- makrolidy farmakologie MeSH
- methicilin rezistentní Staphylococcus aureus účinky léků genetika MeSH
- mikrobiální testy citlivosti metody MeSH
- mnohočetná bakteriální léková rezistence genetika MeSH
- stafylokokové infekce farmakoterapie mikrobiologie MeSH
- streptogramin B farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Řecko MeSH
Aim: This work studied the impact of the quorum-sensing molecule, farnesol (FAR), on fluconazole (FLC)-resistant Candida albicans isolate CY 1123 compared with the susceptible standard strain C. albicans SC5314. The genes encoding efflux pumps belonging to the ATP-binding cassette (ABC) and major facilitator superfamilies, together with overexpression or point mutation of the ERG11 gene, are the main resistance mechanisms to azole antifungal drugs. Results: The upregulation of genes coding for CDR1, CDR2, and MDR1 were confirmed by qPCR with respect to the housekeeping gene ACT1 in the resistant strain. The contribution of the ERG11 gene was also observed. Markedly, increased pump activity (Cdr1 and/or Cdr2) in the CY 1123 strain was confirmed using diS-C3(3) assay. However, the addition of FAR to the yeasts diminished the difference in staining levels between the SC5314 and CY 1123 strains, demonstrating the concentration-dependent character that could be caused by an effective modulation of Cdr pumps. FAR (60 and 100 μM) was also able to decrease the minimal inhibitory concentrations (MIC50), denoting the inhibition of planktonic cells by 50%, from 8 to 4 μg/mL of FLC when the resistant strain CY 1123 was not cultivated with FLC. However, when it was exposed to 64 μg/mL of FLC, the MIC50 shifted from 64 to 8 μg/mL. Conclusion: Besides the many other effects of FAR on eukaryotic and prokaryotic cells, it also affects ABC efflux transporters, resulting in changes in resistance to azoles in C. albicans isolates. However, this effect is dependent on FAR concentrations.
- MeSH
- ABC transportéry metabolismus MeSH
- antifungální látky farmakologie MeSH
- biologický transport účinky léků MeSH
- Candida albicans účinky léků metabolismus MeSH
- farnesol farmakologie MeSH
- flukonazol farmakologie MeSH
- fungální léková rezistence účinky léků MeSH
- fungální proteiny metabolismus MeSH
- membránové transportní proteiny metabolismus MeSH
- mikrobiální testy citlivosti metody MeSH
- Publikační typ
- časopisecké články MeSH
Alterations in PBP2a have been recognized in cefotaxime-resistant laboratory mutants and β-lactam-resistant clinical isolates of Streptococcus pneumoniae. DNA sequencing revealed fundamental differences between these two settings. Internal stop codons in pbp2a occurred in all three laboratory mutants analyzed, caused by a mutation in pbp2a of mutant C604, and tandem duplications within pbp2a resulting in premature stop codons in another two mutants C403 and C406. In contrast, mosaic PBP2a genes were observed in several penicillin-resistant clinical isolates from South Africa, the Czech Republic, Hungary, and in the clone Poland23F-16, with sequence blocks diverging from sensitive strains by over 4%. Most of these pbp2a variants except pbp2a from the South African strain contained sequences related to pbp2a of Streptococcus mitis B6, confirming that this species serves as reservoir for penicillin-resistance determinants.
- MeSH
- bakteriální geny genetika MeSH
- bakteriální proteiny genetika MeSH
- beta-laktamy farmakologie MeSH
- DNA bakterií genetika MeSH
- lidé MeSH
- mikrobiální testy citlivosti metody MeSH
- mutace genetika MeSH
- peniciliny farmakologie MeSH
- peptidsynthasy genetika MeSH
- proteiny vázající penicilin genetika MeSH
- rezistence na penicilin genetika MeSH
- Streptococcus pneumoniae účinky léků genetika MeSH
- transportní proteiny genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Jihoafrická republika MeSH
- Maďarsko MeSH
The ability to form persisters has been observed in many microorganisms, including Staphylococcus aureus, mainly in the context of chronic infections and the pathogenicity of these microbes. In our research, we have demonstrated that salt or oxidative stress could play a role in the formation of S. aureus persisters outside the host's intracellular interface. We pre-exposed planktonic growing bacterial culture to an oxidative or salt stress and monitored the dynamics of persister formation after ciprofloxacin and gentamicin treatment. In parallel, using the quantitative PCR (qPCR) approach, we determined the expression level of the stress sigma factor SigB. The pre-exposure of bacteria to salt stress caused a 1-2.5 order of magnitude increase in persister formation in the bacterial population after antibiotic exposure, depending on the type and concentration of the antibiotic used. In contrast, oxidative stress only minimally influenced the formation of persisters, without correlation to the antibiotic type and concentration. We have demonstrated that both stress and antibiotic exposure increase the expression of sigB in bacterial populations from very early on. And that the expression level of sigB differs with the type of antibiotic and stress, but no correlation was observed between persister formation and sigB expression. The method used could be helpful in testing the ability that strains can have, to form persisters.
Quantitative changes in antibiotic resistance genes (ARGs) were investigated in six urban wastewater treatment plants (WWTPs) treating municipal and industrial wastewaters. In a selected WWTP, the fate of ARGs was studied in a 1-year time interval and in two phases of wastewater treatment process. Nine ARGs (tetW, tetO, tetA, tetB, tetM, blaTEM, ermB, sul1, and intl1) were quantified in total and their relative abundance assessed by ARG copies/16SrRNA copies. From the tetracycline resistance genes, tetW was the only one detected in all sampled WWTPs. Its relative abundance in the nitrification tank of WWTP5 was found stable during the 1-year period, but was lowered by secondary sedimentation processes in the wastewater treatment down to 24% compared to the nitrification tank. Bacterial isolates showing high tetracycline resistance (minimal inhibition concentrations >100 μg/mL) were identified as members of Acinetobacter, Klebsiella, Citrobacter, Bacillus, and Enterobacter genera. Dynamic shifts in the relative abundance of ermB and sul1 were also demonstrated in wastewater samples from WWTP5.
- MeSH
- Bacteria účinky léků genetika MeSH
- bakteriální geny genetika MeSH
- monitorování životního prostředí metody MeSH
- odpadní voda mikrobiologie MeSH
- rezistence na tetracyklin genetika MeSH
- RNA ribozomální 16S genetika MeSH
- tetracyklin farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
