The aim of this study was to determine the antibacterial and antibiofilm properties of quercetin against clinical isolates of Staphyloccocus aureus and Staphylococcus saprophyticus with resistance profile. The antibacterial activity of quercetin was performed by the determination of the minimum inhibitory concentration (MIC) through the microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). The percentage of inhibition of Staphylococcus spp. biofilm, after treatment with sub-inhibitory concentrations of quercetin (MIC/2 and MIC/4), was evaluated by the violet crystal assay. Quercetin showed an antimicrobial activity against clinical isolates of methicillin-susceptible S.

The present study aimed to characterize the susceptibility profile of Pseudomonas aeruginosa and Acinetobacter spp. clinical isolates to polymyxin B in a public hospital in Recife-PE, Brazil, between the years of 2018 and 2019, as well as to search for the presence of the mcr-1 gene and evaluate the interaction between polymyxin B and usnic acid against these isolates. The strains were identified using the BD Phoenix™ automated system and the agar-spot test was used to determine the susceptibility profile to polymyxin B. The minimum inhibitory concentrations (MICs) of usnic acid and polymyxin B were determined through the broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). Subsequently, Polymerase Chain Reaction (PCR) was performed to detect the mcr-1 gene in the isolates. The interaction between usnic acid and polymyxin B was evaluated by the Checkerboard assay. Among 34 isolates of P. aeruginosa, 26.5% (9/34) were positive for the polymyxin B agar-spot test, and 11.8% (4/34) presented an intermediate susceptibility (MIC = 4 μg/mL), while 14.7% (5/34) presented antimicrobial resistance with MIC values ranging from 8 to 32 μg/mL. Among 38 isolates of Acinetobacter spp., 13.2% (5/38) were positive for the polymyxin B agar-spot test and all of them were resistant to polymyxin B with a MIC value > 32 μg/mL. The mcr-1 gene was not detected in the clinical isolates. Regarding usnic acid, it presented a moderate antibacterial activity against two P. aeruginosa isolates (MIC = 250 μg/mL) and no activity was detected against the others. A synergistic effect between usnic acid and polymyxin B was observed against three clinical isolates of P. aeruginosa which were resistant to polymyxin B (FICI ≤ 0.5). Therefore, it was possible to observe that usnic acid is a promising candidate to be used in combination with polymyxin B against infections caused by resistant P. aeruginosa.

Antimicrobial resistance (AMR) represents a critical obstacle to public health worldwide, due to the high incidence of strains resistant to available antibiotic therapies. In recent years, there has been a significant increase in the prevalence of resistant epidemic strains, associated with this, public health authorities have been alarmed about a possible scenario of uncontrolled dissemination of these microorganisms and the difficulty in interrupting their transmission, as nosocomial pathogens with resistance profiles previously considered sporadic. They become frequent bacteria in the community. In addition, therapy for infections caused by these pathogens is based on broad-spectrum antibiotic therapy, which favors an increase in the tolerance of remaining bacterial cells and is commonly associated with a poor prognosis. In this review, we present the current status of epidemic strains of methicillin-resistant Staphylococcus aureus (MRSA), Vancomycin-resistant Enterococcus (VRE), MDR Mycobacterium tuberculosis , extended-spectrum β-lactamase-producing Enterobacterales (ESBL), Klebsiella pneumoniae carbapenemase (KPC), and—New Delhi Metallo-beta-lactamase-producing Pseudomonas aeruginosa (NDM).

Justicia pectoralis Jacq. (Acanthaceae) leaves currently found in the Brazilian north-east are widely used to treat diabetes, menstrual pains, asthma, and other disorders. This work aimed to identify the phytochemical characterization and biological activities of J. pectoralis leaf extracts. The plant material was ground and the crude extracts were obtained with water or acetone: water (7:3 v/v), yielding aqueous (JPA), and organic (JPO) extracts. Phytochemical characterization was performed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Cytotoxicity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay and trypan blue (TB) exclusion assay in peripheral blood mononuclear cells (PBMCs), BALB/c splenocytes, and neoplastic cells (TOLEDO, K562, DU-145, and PANC-1) at 1, 10, and 100 μg/mL. Antibacterial activity was evaluated using the microdilution test to obtain the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Cytokines, IFN-γ, and IL-17A from culture supernatants of BALB/c mice splenocytes were measured by sandwich ELISA. In the TLC analysis, both JPA and JPO extracts presented coumarin and flavonoids. In addition, HPLC was able to identify coumarin, apigenin, and ellagic acid in both extracts. JPO IC50 was 57.59 ± 1.03 μg/mL (MTT) and 69.44 ± 8.08 μg/mL (TB) in TOLEDO. MIC value of JPO against Acinetobacter baumannii and Klebsiella pneumoniae was 500 μg/mL. JPO (100 μg/mL) significantly inhibited IFN-γ levels (p=0.03). J. pectoralis is a potential candidate to be further investigated as an IFN-γ inhibitory agent and against Acinetobacter baumannii and Klebsiella pneumoniae.

O tratamento de infecções causadas por enterobactérias produtoras de enzimas β-lactamases de espectro estendido (ESBLs) está cada vez mais desafiador, de forma que o uso indiscriminado e exacerbado de antibióticos promoveu a resistência e disseminação bacteriana destes patógenos, tornando o tratamento destas bactérias um desafio para a saúde pública. Levando em consideração que os aminoglicosídeos são os antibióticos indicados para o tratamento clínico de infecções causadas pelas enterobactérias, o objetivo dessa revisão foi descrever a utilização e eficácia dos aminoglicosídeos como estratégia terapêutica para combater as infecções causadas por enterobactérias produtoras de ESBLs.  Foi realizada uma revisão bibliográfica através de buscas nas bases PubMed, Scientific Eletronic Library On-line (SCIELO) e Scholar Google, selecionando artigos publicados entre 2011 a 2020, em inglês, com os seguintes descritores:  Bactérias gram-negativas, Resistência e Infecções. Os resultados mostraram que a plazomicina apresenta eficácia frente a cepas de Citrobacter spp., Klebsiella spp. e Enterobacter spp. produtoras de ESBLs, enquanto gentamicina, tobramicina e apramicina apresentam eficácia frente a E. coli, Burkholderia spp., Serratia spp., Citrobacter spp., Enterobacter spp. e Klebsiella spp. produtoras de ESBLs. Com relação à terapia combinada, pode-se observar que a combinação entre dois aminoglicosídeos ou entre aminoglicosídeos e outros antibióticos promoveram efeito sinérgico quando comparado com a monoterapia frente a E. coli, Enterobacter spp., Enterobacter cloacae e principalmente Klebsiella pneumonia produtoras de ESBLs. Portanto, os aminoglicosídeos vêm demonstrando grande potencial frente a esse grupo de bactérias as quais representam um grande desafio para a classe médica.

No abstract

Polymyxins were discovered in the 1940s and were used to treat infections caused by gram-negative bacteria. These molecules act by destroying the cell membrane through the destabilization of phospholipids and lipopolysaccharides (LPS). Due to adverse effects, such as nephrotoxicity and neurotoxicity, this class had seen limited use. However, with the evolution of antimicrobial resistance to commercial drugs, the use of polymyxins has resumed, and over time, strains resistant to this drug have been observed. Currently, resistant bacteria this antimicrobial are found in hospital environments, and non-anthropized environments. This occurrence constitutes a global human and environmental health problem that is of concern to the population, health professionals, and researchers. Thus, this review was conducted with the objective of describing the mechanisms and the occurrence of bacterial resistance to polymyxins, and to demonstrate the relationship between multi-resistant strains of clinical and environmental origins.

The aim of this preliminary study was to identify microorganisms with antimicrobial resistance profile and biofilm producers in oropharynx of Rupornis magnirostris and Caracara plancus. Six R. magnirostris and six C. plancus maintained in Triage Center for Wild Animals (CETAS) facilities were studied. Coagulase-positive staphylococci (CoPS), enterobacteria, and yeasts were identified by the biochemical analysis or MALDI-TOF mass spectrometry. The resistance profile of the microorganisms was analyzed according to CLSI. The biofilm production was evaluated by Congo red and violet crystal staining methods. Among the 12 birds, 10 presented strains of CoPS and/or enterobacteria with resistance profile, such as methicillin-resistant CoPS (MR-CoPS), vancomycin-resistant CoPS (VR-CoPS), extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL), and Klebsiella pneumoniae carbapenemase- (KPC-) producing bacteria. Regards the fungal analysis, Candida spp., Cryptococcus spp., Rhodotorula mucilaginosa, R. glutinis, and Trichosporon coremiiforme were identified. All the Trichosporon coremiiforme strains were resistant to amphotericin B, as well as all the Rhodotorula mucilaginosa exhibited resistance to fluconazole. Related to the biofilm production, among the 8 CoPS, 27 enterobacteria, and 10 yeasts isolates, 3, 16, and 7 strains were biofilm producers, respectively. Thus, the presence of these microorganisms in birds of prey is worrisome, highlighting its possible influence in the spread of infections in urban centers.