Panorama of Bacterial Infections Caused by Epidemic Resistant Strains.

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 ß-lactamase-producing Enterobacterales (ESBL), Klebsiella pneumoniae carbapenemase (KPC), and-New Delhi Metallo-beta-lactamase-producing Pseudomonas aeruginosa (NDM).

Ceftazidime and Usnic Acid Encapsulated in Chitosan-Coated Liposomes for Oral Administration against Colorectal Cancer-Inducing Escherichia coli.

Escherichia coli has been associated with the induction of colorectal cancer (CRC). Thus, combined therapy incorporating usnic acid (UA) and antibiotics such as ceftazidime (CAZ), co-encapsulated in liposomes, could be an alternative. Coating the liposomes with chitosan (Chi) could facilitate the oral administration of this nanocarrier. Liposomes were prepared using the lipid film hydration method, followed by sonication and chitosan coating via the drip technique. Characterization included particle size, polydispersity index, zeta potential, pH, encapsulation efficiency, and physicochemical analyses. The minimum inhibitory concentration and minimum bactericidal concentration were determined against E. coli ATCC 25922, NCTC 13846, and H10407 using the microdilution method. Antibiofilm assays were conducted using the crystal violet method. The liposomes exhibited sizes ranging from 116.5 ± 5.3 to 240.3 ± 3.5 nm and zeta potentials between +16.4 ± 0.6 and +28 ± 0.8 mV. The encapsulation efficiencies were 51.5 ± 0.2% for CAZ and 99.94 ± 0.1% for UA. Lipo-CAZ-Chi and Lipo-UA-Chi exhibited antibacterial activity, inhibited biofilm formation, and preformed biofilms of E. coli. The Lipo-CAZ-UA-Chi and Lipo-CAZ-Chi + Lipo-UA-Chi formulations showed enhanced activities, potentially due to co-encapsulation or combination effects. These findings suggest potential for in vivo oral administration in future antibacterial and antibiofilm therapies against CRC-inducing bacteria.

Gram-negative bacilli carrying mcr gene in Brazil: a pathogen on the rise.

The incidence of infections caused by resistant Gram-negative pathogens has become a critical factor in public health due to the limitation of therapeutic options for the control of infections caused, especially, by Enterobacteriaceae (Escherichia coli and Klebsiella pneumoniae), Pseudomonas spp., and Acinetobacter spp. Thus, given the increase in resistant pathogens and the reduction of therapeutic options, polymyxins were reintroduced into the clinic. As the last treatment option, polymyxins were regarded as the therapeutic key, since they were one of the few classes of antimicrobials that had activity against multidrug-resistant Gram-negative bacilli. Nonetheless, over the years, the frequent use of this antimicrobial has led to reports of resistance cases. In 2015, mcr (mobile colistin resistance), a colistin resistance gene, was described in China. Due to its location on carrier plasmids, this gene is characterized by rapid spread through conjugation. It has thus been classified as a rising threat to public health worldwide. In conclusion, based on several reports that show the emergence of mcr in different regional and climatic contexts and species of isolates, this work aims to review the literature on the incidence of the mcr gene in Brazil in different regions, types of samples identified, species of isolates, and type of carrier plasmid.

Efficacy and non-toxicity of ciclopirox olamine-loaded liposomes against Cryptococcus neoformans clinical isolates.

The aim of this study was to evaluate the efficacy and non-toxicity of ciclopirox olamine-loaded liposomes against Cryptococcus neoformans clinical isolates. Initially, 24-1 fractional experimental design was carried out to obtain an optimized formulation of liposomes containing CPO (CPO-LipoC), which were then used to prepare stealth liposomes (CPO-LipoS). Liposomal formulations were characterized by their mean size diameter, polydispersity index (PDI), and drug encapsulation efficiency (EE%). Immunosuppressed mice were exposed to CPO-LipoS at 0.5 mg/kg/day for 14 days to verify possible histopathological alterations in the liver and kidneys. Immunosuppressed mice infected with C. neoformans were treated with CPO-LipoS at 0.5 mg/kg/day for 14 days to quantify the fungal burden in spleen, liver, lungs, and brain. CPO-LipoS presented a mean size diameter, PDI, and EE% of 101.4 ± 0.7 nm, 0.307, and 96.4 ± 0.9%, respectively. CPO-LipoS was non-toxic for the liver and kidneys of immunosuppressed mice. At the survival curve, all infected animals submitted to treatment with CPO-LipoS survived until the end of the experiment. Treatment with CPO-LipoS reduced C. neoformans cells in the spleen (59.3 ± 3.4%), liver (75.0 ± 3.6%), lungs (75.7 ± 6.7%), and brain (54.2 ± 3.2%). CPO-LipoS exhibit antifungal activity against C. neoformans, and the encapsulation of CPO into stealth liposomes allows its use as a systemic drug for treating cryptococcosis.

Emergence of rmtD1 gene in clinical isolates of Pseudomonas aeruginosa carrying blaKPC and/or blaVIM-2 genes in Brazil.

OBJECTIVES: The aim of the present study is to describe clinical aminoglycoside- or carbapenem-resistant Pseudomonas aeruginosa isolates collected between 2018 and 2019 in a hospital in Recife City, Northeastern Brazil. It was done based on phenotypic and molecular markers of antimicrobial resistance, as well as on the clonal diversity of the investigated isolates. METHODS: Thirty-four carbapenem- and/or aminoglycoside-resistant P. aeruginosa isolates were collected in a hospital in Recife City-PE, Brazil. Their antimicrobial susceptibility profile was identified based on the automated BD Phoenix ™ system. In addition, broth microdilution was performed to determine the MICs of tobramycin and polymyxin B. Eventually, isolates were subjected to PCR and sequencing in order to detect the carbapenemase enzyme (blaKPC, blaNDM, blaVIM, blaSPM-1, and blaIMP) and 16S rRNA methylase (armA, rmtB, rmtD, rmtF, and rmtG) genes; ERIC-PCR was conducted for clonal profile determination purposes. RESULTS: Thirty-four of the 64 isolates evaluated in the present study were selected for complementary molecular phenotypic tests, based on sample inclusion criteria. The blaKPC and blaVIM-2 genes were identified in 32.4% (11/34) and 38.2% (13/34) of tested isolates, respectively. The rmtD1 gene was detected in 32.4% (11/34) of analyzed isolates. Eight isolates carried both the blaKPC and rmtD1 genes, whereas blaVIM-2 and rmtD1 genes co-occurrence was detected in three strains; one isolate had all blaKPC, blaVIM-2, and rmtD1 genes. ERIC-PCR molecular typing has evidenced cross-transmission of three pathogenic clones among patients in the hospital. CONCLUSIONS: The present study is a pioneer in describing isolates harboring both blaVIM-2 and rmtD1 genes. Moreover, it emphasizes the need of conducting local molecular epidemiology studies at different time intervals in order to monitor measures adopted to prevent nosocomial infections in different hospital units.

Antimicrobial Resistance Profile and Biofilm Production of Microorganisms Isolated from Oropharynx of Rupornis magnirostris (Gmelin, 1788) and Caracara plancus (Miller, 1777).

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 ß-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.

Synergistic Effect between Usnic Acid and Polymyxin B against Resistant Clinical Isolates of Pseudomonas aeruginosa.

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.

Organic Extract of Justicia pectoralis Jacq. Leaf Inhibits Interferon-γ Secretion and Has Bacteriostatic Activity against Acinetobacter baumannii and Klebsiella pneumoniae.

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.