Exploring the virulence potential of Staphylococcus aureus CC121 and CC152 lineages related to paediatric community-acquired bacteraemia in Manhiça, Mozambique.

Staphylococcus aureus is a frequent agent of bacteraemia. This bacterium has a variety of virulence traits that allow the establishment and maintenance of infection. This study explored the virulence profile of S.

Antimicrobial resistance and clonality of causing bacteraemia in children admitted to the Manhiça District Hospital, Mozambique, over two decades.

Background: is one of the main causes of bacteraemia, associated with high mortality, mainly due to the occurrence of multidrug resistant (MDR) strains. Data on antibiotic susceptibility and genetic lineages of bacteraemic are still scarce in Mozambique. The study aims to describe the antibiotic susceptibility and clonality of isolated from blood cultures of children admitted to the Manhiça District Hospital over two decades (2001-2019).

Genetic diversity and antimicrobial resistance profiles of associated with skin and soft-tissue infections in companion animals in Lisbon, Portugal.

is the main bacterial pathogen of skin and soft-tissue infections (SSTIs) in companion animals. Antimicrobial resistance in this species is a growing public health concern. This study aims to characterize a collection of causing SSTIs in companion animals, establishing the main clonal lineages and antimicrobial resistance traits.

Exploring Efflux as a Mechanism of Reduced Susceptibility towards Biocides and Fluoroquinolones in .

is the main bacterial cause of skin and soft tissue infections (SSTIs) in companion animals, particularly dogs. The emergence of methicillin-resistant (MRSP) strains, frequently with multidrug resistance phenotypes is a public health concern. This study aimed to evaluate efflux, a resistance mechanism still poorly characterized in , as a contributor to biocide and fluoroquinolone resistance.

Epidemiology and clinical presentation of community-acquired Staphylococcus aureus bacteraemia in children under 5 years of age admitted to the Manhiça District Hospital, Mozambique, 2001-2019.

Staphylococcus aureus bacteraemia (SAB) is one of the most common bloodstream infections globally. Data on the burden and epidemiology of community-acquired SAB in low-income countries are scarce but needed to define preventive and management strategies. Blood samples were collected from children < 5 years of age with fever or severe disease admitted to the Manhiça District Hospital for bacterial isolation, including S.

Occurrence and Variability of the Efflux Pump Gene across the Genus.

NorA is one of the main native MDR efflux pumps of , contributing to reduced susceptibility towards fluoroquinolones and biocides, but little is known about its variability within or its distribution and conservation among other staphylococci. We screened for sequences homologous to and found it in 61 out of the 63 species described. To the best of our knowledge, this is the first study to report the occurrence of across the genus.

Virulence Potential of Biofilm-Producing , and Causing Skin Infections in Companion Animals.

Coagulase-positive staphylococci (CoPS) account for most bacteria-related pyoderma in companion animals. Emergence of methicillin-resistant strains of (MRSP), (MRSA) or (MRSC), often with multidrug-resistant (MDR) phenotypes, is a public health concern. The study collection comprised 237 staphylococci ( ( = 155), ( = 55) and ( = 27)) collected from companion animals, previously characterized regarding resistance patterns and clonal lineages.

Causing Skin and Soft Tissue Infections in Companion Animals: Antimicrobial Resistance Profiles and Clonal Lineages.

is a relevant agent of skin and soft tissue infections (SSTIs) in animals. Fifty-five comprising all SSTI-related isolates in companion animals, collected between 1999 and 2018 (Lab 1) or 2017 and 2018 (Lab 2), were characterized regarding susceptibility to antibiotics and heavy metals and carriage of antimicrobial resistance determinants. Clonal lineages were established by PFGE, MLST and typing.

Phenotypic and Molecular Traits of Associated with Canine Skin Infections in Portugal.

is among the three most frequent pathogens of canine pyoderma. Yet, studies on this species are scarce. Twenty-seven and one , corresponding to all pyoderma-related isolations from these two species at two veterinary laboratories in Lisbon, Portugal, between 1999 and 2018 (Lab 1) or 2018 (Lab 2), were analyzed.

Proposal of Epidemiological Cutoff Values for Apramycin 15 μg and Florfenicol 30 μg Disks Applicable to .

Apramycin and florfenicol are two antimicrobial agents exclusively used in veterinary medicine. Resistance determinants to these antimicrobial agents have been described in several staphylococci, yet no inhibition zone-based epidemiological cutoff (ECOFF) values are available to detect populations harboring resistance mechanisms. In this study, we propose disk diffusion inhibition zone ECOFF values of for apramycin and florfenicol.

Genetic Diversity of , Coding for a Main Efflux Pump of .

NorA is the best studied efflux system of and therefore frequently used as a model for investigating efflux-mediated resistance in this pathogen. NorA activity is associated with resistance to fluoroquinolones, several antiseptics and disinfectants and several reports have pointed out the role of efflux systems, including NorA, as a first-line response to antimicrobials in . Genetic diversity studies of the gene have described three alleles; , and .

First report on antimicrobial resistance and molecular characterisation of Salmonella enterica serotype Typhi isolated from human specimens in Luanda, Angola.

Objectives: Typhoid fever is a common infection in Africa and, despite scarce surveillance reports, its incidence is commonly considered high by the Angolan health system. Drug-resistant Salmonella enterica serotype Typhi has emerged, making antimicrobial susceptibility testing essential to provide clinical guidance. This is the first report analysing the antimicrobial resistance patterns and population structure of the few S.

Active antimicrobial efflux in Staphylococcus epidermidis: building up of resistance to fluoroquinolones and biocides in a major opportunistic pathogen.

Objectives: To analyse the efflux-mediated response of Staphylococcus epidermidis to ethidium bromide (EtBr), a substrate of multidrug efflux pumps (EPs).

Methods: The susceptible reference strain S. epidermidis ATCC 12228 was exposed to a step-wise adaptation to EtBr.

Mode of action of the 2-phenylquinoline efflux inhibitor PQQ4R against .

Efflux pump inhibitors are of great interest since their use as adjuvants of bacterial chemotherapy can increase the intracellular concentrations of the antibiotics and assist in the battle against the rising of antibiotic-resistant bacteria. In this work, we have described the mode of action of the 2-phenylquinoline efflux inhibitor (4-(2-(piperazin-1-yl)ethoxy)-2-(4-propoxyphenyl) quinolone - PQQ4R), against by studding its efflux inhibitory ability, its synergistic activity in combination with antibiotics, and compared its effects with the inhibitors phenyl-arginine-β-naphthylamide (PAβN) and chlorpromazine (CPZ). The results showed that PQQ4R acts synergistically, in a concentration dependent manner, with antibiotics known to be subject to efflux in reducing their MIC in correlation with the inhibition of their efflux.

In vitro and in silico analysis of the efficiency of tetrahydropyridines as drug efflux inhibitors in Escherichia coli.

The objectives of this study were to evaluate tetrahydropyridine derivatives as efflux inhibitors and to understand the mechanism of action of the compounds by in silico studies. Minimum inhibitory concentration (MIC) determination, fluorometric methods and docking simulations were performed. The compounds NUNL02, NUNL09 and NUNL10 inhibited efflux, and NUNL02 is very likely a substrate of the transporter protein AcrB.

An Experimental Model for the Rapid Screening of Compounds with Potential Use Against Mycobacteria.

Infections caused by Mycobacterium tuberculosis and other mycobacteria are major challenges for global public health. Particularly worrisome are infections caused by multidrug-resistant bacteria, which are increasingly difficult to treat because of the loss of efficacy of the current antibacterial agents, a problem that continues to escalate worldwide. There has been a limited interest and investment on the development of new antibacterial agents in the past decades.

Plasmid-Borne Antimicrobial Resistance of Staphylococcus aureus Isolated in a Hospital in Lisbon, Portugal.

Plasmids play a key role in the genetic plasticity and survival of Staphylococcus aureus in challenging environments. Although many S. aureus plasmids have been described, still few studies portray the plasmid content of a given S.

Enhancing activity of antibiotics against Staphylococcus aureus: Zanthoxylum capense constituents and derivatives.

Six compounds (1-6), isolated from the methanol extract of the roots of the African medicinal plant Zanthoxylum capense Thunb. (Rutaceae), and seven ester derivatives (7-13) were evaluated for their antibacterial activities and modulatory effects on the MIC of antibiotics (erythromycin, oxacillin, and tetracycline) and ethidium bromide (EtBr) against a Staphylococcus aureus reference strain (ATCC 6538). Using the same model, compounds 1-13 were also assessed for their potential as efflux pump inhibitors by a fluorometric assay that measures the accumulation of the broad range efflux pump substrate EtBr.

Membrane transport systems and the biodegradation potential and pathogenicity of genus Rhodococcus.

The Rhodococcus genus contains species with remarkable ability to tolerate toxic compounds and to degrade a myriad of substrates. These substrates have to cross a distinctive cell envelope dominated by mycolic acids anchored in a scaffold of arabinogalactan covalently attached to the cell wall peptidoglycan, and a cellular membrane with phospholipids, whose composition in fatty acids can be rapidly altered in response to environmental conditions. The hydrophobic nature of the cell envelope facilitates the entrance of hydrophobic molecules but some substrates require active transport systems.

Multidrug Efflux Pumps in Staphylococcus aureus: an Update.

The emergence of infections caused by multi- or pan-resistant bacteria in the hospital or in the community settings is an increasing health concern. Albeit there is no single resistance mechanism behind multiresistance, multidrug efflux pumps, proteins that cells use to detoxify from noxious compounds, seem to play a key role in the emergence of these multidrug resistant (MDR) bacteria. During the last decades, experimental data has established their contribution to low level resistance to antimicrobials in bacteria and their potential role in the appearance of MDR phenotypes, by the extrusion of multiple, unrelated compounds.

Resistance to Antimicrobials Mediated by Efflux Pumps in Staphylococcus aureus.

Resistance mediated by efflux has been recognized in Staphylococcus aureus in the last few decades, although its clinical relevance has only been recognized recently. The existence of only a few studies on the individual and overall contribution of efflux to resistance phenotypes associated with the need of well-established methods to assess efflux activity in clinical isolates contributes greatly to the lack of solid knowledge of this mechanism in S. aureus.

Exploring the contribution of efflux on the resistance to fluoroquinolones in clinical isolates of Staphylococcus aureus.

Background: Antimicrobial resistance mediated by efflux systems is still poorly characterized in Staphylococcus aureus, despite the description of several efflux pumps (EPs) for this bacterium. In this work we used several methodologies to characterize the efflux activity of 52 S. aureus isolates resistant to ciprofloxacin collected in a hospital in Lisbon, Portugal, in order to understand the role played by these systems in the resistance to fluoroquinolones.