Search Results (65)

Background: In Staphylococcus aureus, antimicrobial resistance (AMR) imposes significant fitness costs (FCs), including reduced growth rate, interbacterial competitiveness, and virulence. However, the FC molecular basis remains poorly understood. This study investigated the FC omic basis and compensatory adaptations in high-risk HA-, LA-, and CA-MRSA, acquiring mono- or cross-resistance to second-line daptomycin (DAP) and dalbavancin (DAL), as well as reduced susceptibility (RS) to first-line glycopeptides, i.e., vancomycin and teicoplanin (GLYs, i.e., VAN, TEC), related to the specific mechanism of action (MOA)-related AMR-mechanisms and genomic backgrounds, paying increasing FCs. Methods: The FC omic basis associated with mono- or cross- DAP-/DAL-R and GLY-RS were investigated by integrated omics. This study focused on core-genome essential (EG) and accessory virulence gene (VG) SNPomics and transcriptomics by Illumina MiSeq whole-genome sequencing, RNA-seq, and bioinformatic analysis. Results: Moderate impact nsSNPs were identified in EGs related to vital cellular functions and VGs. Comparative EG transcriptomics revealed differential expressions and key dysregulations—via asRNAs—prevalently affecting the protein synthesis and cell-envelope EG clusters, as well as the VG cluster. Conclusions: Our data, firstly, underlined the EG and VG mutation- and transcription-driven omic-based FC burden and the compensatory adaptations associated with the emergence of mono-DAP-R, cross-DAP-R/hGISA, and DAP-R/DAL-R/GISA, linked to specific MOA-related AMR-mechanisms and genomic backgrounds in high-risk HA-, LA-, and CA-MRSA. Full article

Methicillin-resistant Staphylococcus aureus (MRSA) can spread from animals to humans, but how it adapts to infect both is not fully understood. Our review aimed to determine the prevalence of MRSA in livestock, poultry, and companion animals in different countries, including Bangladesh, the Hong Kong SAR, Mainland China, and Sri Lanka. Articles were collected using PubMed, Embase, Web of Science, Scopus, CINAHL, and Google Scholar. Only prevalence studies that followed the PICO guidelines were included. A random-effects model meta-analysis was used to pool the data. The quality of the evidence and bias were assessed using the GRADEpro and Cochrane collaboration tools. Out of 1438 articles, 69 studies were eligible for meta-analysis. The studies showed significant heterogeneity (I² = 97.00%, p < 0.0001) in the prevalence of MRSA colonization. Therefore, a random-effects model was used to determine the pooled prevalence of MRSA colonization, which was found to be 4.92% (95% CI: 3.79% to 6.18%). Begg’s test (p = 0.0002) and Egger’s test (p = 0.0044) revealed publication bias. Subgroup analysis of the pooled prevalence of MRSA showed a significant difference (p < 0.00001) when the subgroups were divided by country, MRSA detection method, whether pre-enrichment was performed or not, study period, sample collection location, and study population. Although significant factors can partially explain the heterogeneity, it is crucial to recognize the heterogeneity within different subgroups. The pooled prevalence of MRSA was found to vary significantly (p < 0.00001) among the study periods and has increased since the study period of 2020. Therefore, it is crucial to continuously monitor and implement measures to control the spread of MRSA in animals to minimize the risk of transmission to humans. Full article

Background: The fitness costs (FCs) of antimicrobial resistance (AMR) are crucial issues in antimicrobial resistance (AMR) onset, spread, and, consequently, public health. In Staphylococcus aureus, AMR can induce significant FCs due to slow growth, low competitiveness, and virulence. Here, we investigated the genomics and FCs emerging for progressively acquiring daptomycin (DAP) and glycopeptide (GLY) reduced susceptibility in MRSA. Methods: Genomics was carried out using Illumina-MiSeq Whole-genome sequencing and bioinformatics. The biological FCs of isogenic MRSA strain pairs progressively acquiring DAP and GLY-reduced susceptibility, under DAP/GLY mono or combined therapy, were performed by in-vitro independent and competitive mixed growth, phenotypic in-vitro virulence analysis, and in-vivo G. mellonella larvae killing. Results: Genomics evidenced four different extremely resistant high-risk clones, i.e., ST-5 N315 HA-MRSA, ST-398 LA-MRSA, ST-22 USA-100 HA-EMRSA-15, and ST-1 MW2 CA-MRSA. In-vitro fitness assays revealed slow growth, lower competitiveness, and reduced virulence, predominantly in Galleria mellonella killing ability, in DAP-S hGISA, DAP-R GSSA, DAP-R hGISA, and DAP-R GISA strains. Conclusions: The occurrence of glycopeptide and daptomycin reduced susceptibility conferred increasing FCs, paid as a gradual reduction in virulence, competitiveness, and slow growth performance. Full article

Background/Objectives: The occurrence of novel variants of staphylococcal cassette chromosome mec (SCCmec) in livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has frequently been reported, posing significant zoonotic concern worldwide. In this study, the occurrence of novel types of SCCmec IX elements was identified in two clonal complex (CC) 398 LA-MRSA strains derived from a pig farm and a slaughterhouse in Korea. Methods: Whole-genome sequence analysis of the two CC398 MRSA-SCCmec IX strains, designated KF1A-1172 and JS1E-122, revealed that these strains are most closely related to previously characterized strains of CC398 LA-MRSA carrying SCCmec V isolated from pig farms in Korea. Results: Further structural analysis of the SCCmec IX in KF1A-1172 and JS1E-122 revealed the presence of multiple ccr gene complexes (ccrA5B3, ccrAB3, and a truncated ccrA1), including ccrA1B1 genes for SCCmec type IX. In addition, the pseudo-SCC (ΨSCC) elements, genes associated with the type 1 restriction–modification (RM) system, and zinc resistance gene czrC, were identified in the SCCmec IX. Conclusions: These findings suggest that the multiple recombination events of elements derived from various SCCmec types contributed to the emergence of the novel SCCmec IX variant. The identification of these novel SCCmec IX types in CC398 LA-MRSA also suggests that epidemiological diversification of SCCmec IX in CC398 LA-MRSA is an ongoing event, necessitating continued surveillance on the emergence of novel SCCmec variants. This study is the first to report the complete genome sequences of CC398 MRSA carrying SCCmec IX in Korea. Full article

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is widespread in European pig production and poses an occupational hazard to farm workers and their household members. Farm workers are exposed to LA-MRSA through direct contact with pigs and airborne transmission, enabling bacteria to be carried home in the nose or on the skin. Consequently, it is important to consider LA-MRSA in a one-health context, studying human exposure by examining LA-MRSA levels in pigs, air, and dust in the farm environment. In this investigation, LA-MRSA levels were quantified in nasal swab samples from the pigs, air samples, and dust at three different time points in a farm rearing pigs from approx. 30 kg until slaughter. Sampling was repeated across seven batches of pigs, resulting in the analysis of 504 nasal swab samples, alongside air and dust samples. LA-MRSA was cultured and quantified on MRSA2 agar plates. Findings revealed significant batch-to-batch variation and a significant 94.1% decrease in LA-MRSA levels during the rearing period. Despite this decline, all nasal swab samples tested positive, with the highest level reaching 353,000 cfu in a sample. Among the 42 air samples, LA-MRSA levels were low to moderate, with a maximum of 568 and an average of 63 cfu/m³. In the 28 dust samples collected during the second and third sampling periods, LA-MRSA counts were high, reaching up to 37,272 cfu/g, with an average of 17,185 cfu/g. The results suggest that while LA-MRSA levels in pigs decrease with age, reaching low levels before slaughter, the bacterium remains highly abundant in dust, posing an occupational hazard to farm workers. Full article

Background/Objectives: Wastewater treatment plants (WWTPs) are hotspots for the spread of antimicrobial resistance into the environment. This study aimed to estimate the proportion of clinically relevant antimicrobial-resistant bacteria in two Spanish urban WWTPs, located in the region of La Rioja (Spain); Methods: Ninety-four samples (48 water/46 sludge) were collected and streaked on ten different selective media, in order to recover the culturable bacterial diversity with relevant resistance phenotypes: Extended-Spectrum β-Lactamase-producing Escherichia coli/Klebsiella pneumoniae (ESBL-Ec/Kp), Carbapenem-resistant Enterobacteriaceae (CR-E), Methicillin-resistant Staphylococcus aureus (MRSA), and Vancomycin-resistant Enterococcus faecium/faecalis (VR-E. faecium/faecalis). Isolates were identified by MALDI-TOF and were tested for antimicrobial susceptibility using the disk diffusion method. The confirmation of ESBL production was performed by the double-disk test; Results: A total of 914 isolates were recovered (31 genera and 90 species). Isolates with clinically relevant resistance phenotypes such as ESBL-Ec/Kp and CR-E were recovered in the effluent (0.4 × 10⁰–4.8 × 10¹ CFU/mL) and organic amendment samples (1.0–10¹–6.0 × 10² CFU/mL), which are discharged to surface waters/agricultural fields. We reported the presence of VR-E. faecium in non-treated sludge and in the digested sludge samples (1.3 × 10¹–1 × 10³ CFU/mL). MRSA was also recovered, but only in low abundance in the effluent (0.2 × 10¹ CFU/mL); Conclusions: This study highlights the need for improved wastewater technologies and stricter regulations on the use of amendment sludge in agriculture. In addition, regular monitoring and surveillance of WWTPs are critical for early detection and the mitigation of risks associated with the spread of antimicrobial resistance. Full article

Multidrug-resistant (MDR) Staphylococcus aureus has been increasingly isolated from pigs and people in close contact with them, especially livestock-associated methicillin-resistant S. aureus (LA-MRSA). In this cross-sectional study, we investigated S. aureus colonization in pigs and farm workers, their resistance profile, and genetic background to estimate interspecies transmission potential within farms from Rio de Janeiro state, Brazil, between 2014 and 2019. We collected nasal swabs from 230 pigs and 27 workers from 16 and 10 farms, respectively. Five MDR strains were subjected to whole genome sequencing. Fourteen (6.1%) pigs and seven (25.9%) humans were colonized with S. aureus, mostly (64–71%) MDR strains. Resistance to clindamycin, erythromycin, penicillin, and tetracycline was the most common among the pig and human strains investigated. MDR strains shared several resistance genes [blaZ, dfrG, fexA, lsa(E), and tet(M)]. Pig and human strains recovered from the same farm shared the same genetic background and antimicrobial resistance profile. LA-MRSA ST398-SCCmecV-t011 was isolated from pigs in two farms and from a farm worker in one of them, suggesting interspecies transmission. The association between pig management practices and MDR S. aureus colonization might be investigated in additional studies. Full article

We investigated the prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pig slaughterhouses from 2018 to 2022 in Japan and the isolates were examined for antimicrobial susceptibility and genetic characteristics by whole-genome analysis. Although the positive LA-MRSA rates on farms (29.6%) and samples (9.9%) in 2022 in Japan remained lower than those observed in European countries exhibiting extremely high rates of confirmed human LA-MRSA infections, these rates showed a gradually increasing trend over five years. The ST398/t034 strain was predominant, followed by ST5/t002, and differences were identified between ST398 and ST5 in terms of antimicrobial susceptibility and the resistance genes carried. Notably, LA-MRSA possessed resistance genes toward many antimicrobial classes, with 91.4% of the ST398 strains harboring zinc resistance genes. These findings indicate that the co-selection pressure associated with multidrug and zinc resistance may have contributed markedly to LA-MRSA persistence. SNP analysis revealed that ST398 and ST5 of swine origin were classified into a different cluster of MRSA from humans, showing the same ST in Japan and lacking the immune evasion genes (scn, sak, or chp). Although swine-origin LA-MRSA is currently unlikely to spread to humans and become a problem in current clinical practice, preventing its dissemination requires using antimicrobials prudently, limiting zinc utilization to the minimum required nutrient, and practicing fundamental hygiene measures. Full article

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has been widespread globally in pigs and humans for decades. Nasal colonization of LA-MRSA is regarded as an occupational hazard to people who are regularly involved in livestock production. Our previous study suggested pig-to-human transmission caused by LA-MRSA clonal complex (CC) 398, using traditional molecular typing methods. Instead, this study aimed to investigate the zoonotic transmission of LA-MRSA CC398 using whole genome sequencing (WGS) technologies. A total of 63 LA-MRSA isolates were identified and characterized in Thailand. Further, the 16 representatives of LA-MRSA CC9 and CC398, including porcine and worker isolates, were subjected to WGS on the Illumina Miseq platform. Core-genome single nucleotide polymorphism (SNP)-based analyses verify the zoonotic transmission caused by LA-MRSA CC398 in two farms. WGS-based characterization suggests the emergence of a novel staphylococcal cassette chromosome (SCC) mec type, consisting of multiple cassette chromosome recombinase (ccr) gene complexes via genetic recombination. Additionally, the WGS analyses revealed putative multi-resistant plasmids and several cross-resistance genes, conferring resistance against drugs of last resort used in humans such as quinupristin/dalfopristin and linezolid. Significantly, LA-MRSA isolates, in this study, harbored multiple virulence genes that may become a serious threat to an immunosuppressive population, particularly for persons who are in close contact with LA-MRSA carriers. Full article

Three Lactococcus lactis strains from the nasal microbiota of healthy pigs were identified as candidates for reducing MRSA in pigs. The safety of nasal administration of a cocktail of these strains was examined in new-born piglets. Six days pre-farrowing, twelve sows were assigned to the placebo or cocktail group (n = 6/group). After farrowing, piglets were administered with either 0.5 mL of the placebo or the cocktail to each nostril. Health status and body weight were monitored at regular time points. Two piglets from three sows/treatment group were euthanised at 24 h, 96 h and 14 d after birth, and conchae, lung and tonsil samples were collected for histopathological and gene expression analysis. Health scores were improved in the cocktail group between d1–5. Body weight and daily gains did not differ between groups. Both groups displayed histological indications of euthanasia and inflammation in the lungs, signifying the findings were not treatment related. The expression of pBD2, TLR9 and IL-1β in the nasal conchae differed between groups, indicating the cocktail has the potential to modulate immune responses. In summary, the L. lactis cocktail was well tolerated by piglets and there was no negative impact on health scores, growth or lung histopathology indicating that it is safe for administration to new-born piglets. Full article

Methicillin-resistant Staphylococcus aureus (MRSA) is a universal threat. Once being well established in the healthcare setting, MRSA has undergone various epidemiological changes. This includes the emergence of more aggressive community-acquired MRSA (CA-MRSA) and the occurrence of MRSA which have their origin in animal breeding, called livestock-associated MRSA (LA-MRSA). Emergence of new clones as well as changes in the occurrence of some clonal lineages also describes the fluctuating dynamic within the MRSA family. There is paucity of data describing the possible impact of the COVID-19 pandemic on the MRSA dynamics. The aim of the study was the analysis of MRSA isolates in a three-year time period, including the pre-COVID-19 years 2018 and 2019 and the first year of the pandemic 2020. The analysis includes prevalence determination, antibiotic susceptibility testing, spa typing, and detection of genes encoding the PVL toxin. The MRSA rate remained constant throughout the study period. In terms of a dynamic within the MRSA family, only a few significant changes could be observed, but all except one occurred before the start of the COVID-19 pandemic. In summary, there was no significant impact of the COVID-19 pandemic on MRSA in Austria. Full article

The creation of mitochondria-targeted vector systems is a new tool for the treatment of socially significant diseases. Phosphonium groups provide targeted delivery of drugs through biological barriers to organelles. For this purpose, a new class of alkyl(diethylAmino)(Phenyl) Phosphonium halides (APPs) containing one, two, or three diethylamino groups was obtained by the reaction of alkyl iodides (bromides) with (diethylamino)(phenyl)phosphines under mild conditions (20 °C) and high yields (93–98%). The structure of APP was established by NMR and XRD. A high in vitro cytotoxicity of APPs against M-HeLa, HuTu 80, PC3, DU-145, PANC-1, and MCF-7 lines was found. The selectivity index is in the range of 0.06–4.0 μM (SI 17-277) for the most active APPs. The effect of APPs on cancer cells is characterized by hyperproduction of ROS and depolarization of the mitochondrial membrane. APPs induce apoptosis, proceeding along the mitochondrial pathway. Incorporation of APPs into lipid systems (liposomes and solid lipid nanoparticles) improves cytotoxicity toward tumor cells and decrease toxicity against normal cell lines. The IC₅₀s of lipid systems are lower than for the reference drug DOX, with a high SI (30–56) toward MCF-7 and DU-145. APPs exhibit high selective activity against Gram-positive bacteria S. aureus 209P and B. segeus 8035, including methicillin-resistant S. aureus (MRSA-1, MRSA-2), comparable to the activity of the fluoroquinolone antibiotic norfloxacin. A moderate in vivo toxicity in CD-1 mice was established for the lead APP. Full article

Natural remedies derived from plants have a long history of usage in the treatment of a wide variety of severe diseases. This study aims to develop a Capparis spinosa (C. spinosa) oil nanoemulgel and evaluate its antimicrobial, anticancer, and anti-inflammatory effects. C. spinosa oil was developed into a nanoemulsion using a self-nanoemulsifying method with Span 80 and Tween 80 as emulsifying agents. Carbopol hydrogel was mixed with the nanoemulsion to form nanoemulgel. After this, we tested the particle size, polydispersity index (PDI), rheology, antimicrobial, cytotoxic, and anti-inflammatory activities. The nanoemulsion formulation that has a PDI of 0.159 and a particle size of 119.87 nm is considered to be the optimum formulation. The C. spinosa oil nanoemulgel gave results similar to its nanoemulsion, where it had a PDI lower than 0.2, droplet size below 200 nm, and zeta potential less than −35. Also, it had a pseudoplastic rheological behavior. The C. spinosa oil nanoemulgel showed a significant effect on Methicillin-Resistant Staphylococcus Aureus (MRSA) and Klebsiella pneumoniae (K. pneumonia) (ATCC 13883) with zone inhibition diameters of 33 ± 1.9 mm and 30 ± 1.4 mm, respectively, as well as significant activities on the MCF-7, HepG2, and HeLa cancer cell lines with IC₅₀ values of 194.98, 91.2, and 251.18 µg/mL, respectively, which were better than those of the original oil. Regarding its anti-inflammatory effect, C. spinosa oil had a positive impact on both COX-1 and COX-2 but was more selective for COX-1. Consequently, simple nanotechnology techniques provide a promising step forward in the development of pharmacological dosage forms. Full article

Since the mid-2000s, livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has been identified among pigs worldwide, CC398 being the most relevant LA-MRSA clone. In the present work, nasal swabs were taken from healthy pigs of different age categories (25 to 154 days) from 2019 to 2021 in four intensive farms located in three provinces of Argentina. The aim of the present study was to characterize the first LA-MRSA isolates that colonized healthy fattening pigs in Argentina in terms of their resistance phenotype and genotype and to know the circulating clones in the country. Antimicrobial susceptibility, presence of the mecA gene and PCR screening of CC398 were evaluated in all the isolates. They were resistant to cefoxitin, penicillin, tetracycline, chloramphenicol and ciprofloxacin but susceptible to nitrofurantoin, rifampicin, vancomycin and linezolid. Furthermore, 79% were resistant to clindamycin and lincomycin, 68% to erythromycin, 58% to gentamicin and 37% to trimethoprim/sulfamethoxazole. All the isolates were multidrug resistant. The clonal relation was assessed by SmaI-PFGE (pulsed-field gel electrophoresis) and a representative isolate of each PFGE type was whole genome sequenced by Illumina. MLST (multilocus sequence typing), resistance and virulence genes and SCCmec typing were performed on sequenced isolates. The isolates were differentiated in three clonal types by PFGE, and they belonged to sequence-type ST398 (58%) and ST9, CC1 (42%) by MLST. SCCmec typeV and several resistance genes detected showed complete correlation with resistance phenotypes. The present study revealed that LA-MRSA colonizing healthy pigs in Argentina belongs to CC398 and CC1, two MRSA lineages frequently associated to pigs in other countries. Full article

In livestock, the importance of hygiene management is gaining importance within the context of biosecurity. The aim of this study was to monitor the implementation of biosecurity and hygiene procedures in 20 swine herds over a 12-month period, as driven by tailor-made plans, including training on-farm. The measure of adenosine triphosphate (ATP) environmental contents was used as an output biomarker. The presence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) and extended-spectrum β-lactamase producing Escherichia coli (ESBL-E. coli) was also investigated as sentinels of antibiotic resistance. A significant biosecurity improvement (p = 0.006) and a reduction in the ATP content in the sanitised environment (p = 0.039) were observed. A cluster including 6/20 farms greatly improved both biosecurity and ATP contents, while the remaining 14/20 farms ameliorated them only slightly. Even if the ESBL-E. coli prevalence (30.0%) after the hygiene procedures significantly decreased, the prevalence of LA-MRSA (22.5%) was unaffected. Despite the promising results supporting the adoption of tailor-made biosecurity plans and the measure of environmental ATP as an output biomarker, the high LA-MRSA prevalence still detected at the end of the study underlines the importance of improving even more biosecurity and farm hygiene in a one-health approach aimed to preserve also the pig workers health. Full article