Synthesis of 1,3,4-oxadiazoles with 4-methoxynaphthalene ring: discovering new compounds with antimicrobial activity.

Background: Paracoccidioidomycosis (PCM) is a systemic infection caused by Paracoccidioides spp. (Pb). PCM can be associated or clinically confused with tuberculosis (TB), another pulmonary infection, caused by Mycobacterium tuberculosis (Mtb). Futhermore, the long treatment time of TB and PCM and the cases of TB drug resistance impose difficulties for the cure of these diseases. Results: New 1,3,4-oxadiazoles containing the 4-methoxynaphthalene ring were synthesized and their antimicrobial activity was evaluated against Pb and Mtb. The derivative 6n (with 2-hydroxy-5-nitrophenyl subunit) is the most promising of the series. Conclusion: The 1,3,4-oxadiazole 6n can be used as a prototype drug candidate, with anti-Pb and anti-MTb activities, showing a broad-spectrum profile for the treatment of both pulmonary infections.

Plants of the Phytolaccaceae family with antimicrobial activity: A systematic review.

Phytolaccaceae is a plant family of the order Caryophyllales, which includes species used in traditional medicine to treat diseases. The purpose of this study was to investigate Phytolaccaceae family plants with potential antimicrobial action, through a systematic review. The study was conducted following the criteria of PRISMA protocol. The search was performed in the electronic databases PubMed, Web of Science, Scopus, and LILACS, in March 2021. The search strategy used free descriptors and terms, limiting articles to the English language, regardless of publication year. The risk of bias and the quality of publications were based on the CONSORT checklist, modified for in vitro studies and SYRCLE's RoB tool for in vivo study. Five independent judges performed quality assessments of publications and risk of bias analysis. Ninety-five publications were retrieved from the databases and, after screening and eligibility criteria, 22 articles remained, from 1998 to 2019. In the selected studies, the plants were obtained from eight countries. In vivo and in vitro studies of extracts from the Phytolaccaceae family plants, evaluating antibacterial (8 publications), antifungal (8), anti-Trypanosoma (2), anti-Leishmania (2), antiviral (1), and antiamoebic (1) activities, are included. The plant species identified belong to genera Petiveria, Phytolacca, Gallesia, Trichostigma, and Seguieria. The risk of bias in the 22 publications both in vitro and in vitro was suboptimal. The evidence obtained showed that the Phytolaccaceae family, a source of plants with antimicrobial action, can serve as a basis for the creation of new herbal medicines, expanding the possibility of treatment for infectious diseases and stimulating their preservation and biodiversity. However, more high-quality studies are needed to establish the clinical efficacy of the plant.

PanB over-representation as part of pyrazinamide action: a proteomic insight.

Background: Pyrazinamide (PZA) represents a milestone as a first-line antituberculosis drug due to its sterilizing activity against Mycobacterium tuberculosis. Materials & Methods: The protein changes induced by subinhibitory PZA exposure of M. tuberculosis in acidic pH were evaluated by a proteomic approach. Results: Among the 1059 M. tuberculosis proteins identified, the specific acidification in the culture medium induced the over-representation of MurF (Rv2157c), and its under-representation was induced by 12 h of PZA exposure. PanB (Rv2225) was over-represented at 24 h of PZA exposure. Conclusion: The authors highlight the over-representation of PanB in M. tuberculosis correlates of PZA action in acidic pH, reinforcing the role of the pantothenate pathway as a bacillus drug target to be explored.

New insights on Ethambutol Targets in Mycobacterium tuberculosis.

BACKGROUND: In recent years, very few effective drugs against Mycobacterium tuberculosis have emerged, which motivates the research with drugs already used in the treatment of tuberculosis. Ethambutol is a bacteriostatic drug that affects cell wall integrity, but the effects of this drug on bacilli are not fully exploited. OBJECTIVE: Based on the need to better investigate the complex mechanism of action of ethambutol, our study presented the proteome profile of M. tuberculosis after different times of ethambutol exposure, aiming to comprehend the dynamics of bacilli response to its effects. M. tuberculosis was exposed to ½ MIC of ethambutol at 24 and 48 hours. The proteins were identified by MALDI-TOF/TOF. RESULTS: The main protein changes occurred in metabolic proteins as dihydrolipoyl dehydrogenase (Rv0462), glutamine synthetase1 (Rv2220), electron transfer flavoprotein subunit beta (Rv3029c) and adenosylhomocysteinase (Rv3248c). CONCLUSION: Considering the functions of these proteins, our results support that the intermediary metabolism and respiration were affected by ethambutol and this disturbance provided proteins that could be explored as additional targets for this drug.

Activity of rifampicin and linezolid combination in Mycobacterium tuberculosis.

BACKGROUND: Linezolid (LZD) is not commonly used for treating tuberculosis (TB), but in some patients with drug-resistant TB it is being used. However, the in vitro LZD activity, in combination with rifampicin (RIF) against Mycobacterium tuberculosis has not been fully elucidated. AIMS: The aim of this study was to evaluate the in vitro activity of RIF/LZD combination against M. tuberculosis clinical isolates. MATERIALS AND METHODS: The activity of the RIF/LZD combination was firstly determined in M. tuberculosis H37Rv, 14 susceptible, 9 isoniazid nonresistant and 14 multi-drug resistant (MDR) M. tuberculosis clinical isolates by modified checkerboard assay, Resazurin Drugs Combination Microtiter Assay (REDCA). After, the Time Kill Curve Assay, at 0.5 × MIC of drugs, in combination and alone, was performed in M. tuberculosis H37Rv and 8 (20.5%) of those clinical isolates, which the RIF/LZD combination showed to have synergistic effect by the checkerboard assay. RESULTS AND CONCLUSION: By Time Kill Curve Assay, we could observe in M. tuberculosis H37Rv and susceptible isolates, that LZD alone, at sub inhibitory concentration, has poor effect on the bacillus death. In some cases, the bacillus growth stayed constant while in others showed regrowth at the eighth day of drug exposure. RIF alone exhibits potent concentration-dependent bactericidal activity, and was strongly dependent by the drug exposure time. The RIF/LZD combination accomplished a bacteriostatic effect in the reference strain and susceptible isolates. For the RIF resistant isolates, the RIF/LZD combination did not enhance the effect in killing bacillus. In this sense, additional, in vitro and in vivo studies are needed to evaluate the effect of RIF/LZD combination in order to better understand the adjunctive action of LZD in the treatment of TB and prevent the emergence of mutants with resistance to the available anti-TB drugs.

Mutations in catalase-peroxidase KatG from isoniazid resistant Mycobacterium tuberculosis clinical isolates: insights from molecular dynamics simulations.

The current multidrug therapy for tuberculosis (TB) is based on the use of isoniazid (INH) in combination with other antibiotics such as rifampin, ethambutol and pyrazinamide. Literature reports have shown that Mycobacterium tuberculosis, the causative agent of TB, has become resistant to this treatment by means of point mutations in the target enzymes of these drugs, such as catalase-peroxidase (KatG). By means of equilibrium molecular dynamics in the presence of the ligand, this work evaluated ten point mutations described in the enzyme KatG that are related to resistance to INH . The results showed that the resistance mechanism is related to stereochemical modifications at the N-terminal domain of the protein, which restrict INH access to its catalytic site, not involving mechanisms of electrostatic nature. These results show insights that can be useful for the identification of new anti-TB drugs which may be able to circumvent this mechanism of resistance.

Activity of rifampicin and linezolid combination in Mycobacteriumtuberculosis

Background: Linezolid (LZD) is not commonly used for treating tuberculosis (TB), but in some patients with drug-resistant TB it is being used. However, the in vitro LZD activity, in combination with rifampicin (RIF) against Mycobacterium tuberculosis has not been fully elucidated.Aims: The aim of this study was to evaluate the in vitro activity of RIF/LZD combination against M. tuberculosis clinical isolates.Materials and methods: The activity of the RIF/LZD combination was firstly determined in M. tuberculosis H37Rv, 14 susceptible, 9 isoniazid nonresistant and 14 multi-drug resistant (MDR) M. tuberculosis clinical isolates by modified checkerboard assay, Resazurin Drugs Combination Microtiter Assay (REDCA). After, the Time Kill Curve Assay, at 0.5 MIC of drugs, in combination and alone, was performed in M. tuberculosis H37Rv and 8 (20.5%) of those clinical isolates, which the RIF/LZD combination showed to have synergistic effect by the checkerboard assay.Results and conclusion: By Time Kill Curve Assay, we could observe in M. tuberculosis H37Rv and susceptible isolates, that LZD alone, at sub inhibitory concentration, has poor effect on the bacillus death. In some cases, the bacillus growth stayed constant while in others showed regrowth at the eighth day ofdrug exposure. RIF alone exhibits potent concentration-dependent bactericidal activity, and was strongly dependent by the drug exposure time. The RIF/LZD combination accomplished a bacteriostatic effect in the reference strain and susceptible isolates. For the RIF resistant isolates, the RIF/LZD combination did not enhance the effect in killing bacillus. In this sense, additional, in vitro and in vivo studies are needed to evaluate the effect of RIF/LZD combination in order to better understand the adjunctive action of LZD in the treatment of TB and prevent the emergence of mutants with resistance to the available anti-TB drugs.

Performance of Hitchens-Pike-Todd-Hewitt medium for group B streptococcus screening in pregnant women.

Group B streptococcus (GBS), which commonly colonizes the female genital tract and rectum, can cause infections in newborns with varying severity, possibly leading to death. The aim of the present study was to evaluate Hitchens-Pike-Todd-Hewitt (HPTH) medium performance for GBS screening in pregnant women. A descriptive analytical cross-sectional study was performed with 556 pregnant women, of which 496 were at 35-37 weeks of gestation and 60 were at ≥ 38 weeks of gestation. The study was conducted from September 2011 to March 2014 in northern Paraná, Brazil. Vaginal and anorectal clinical specimens from each pregnant woman were plated on sheep blood agar (SBA) and seeded on HPTH medium and Todd-Hewitt enrichment broth. Of the 496 pregnant women at 35-37 weeks of gestation, 141 (28.4%) were positive for GBS, based on the combination of the three culture media and clinical specimens. The GBS colonization rates that were detected by each medium were 22.2% for HPTH medium, 21.2% for SBA, and 13.1% for Todd-Hewitt enrichment broth. Of the 60 pregnant women at ≥ 38 weeks of gestation, seven (11.7%) were positive for GBS. These results demonstrate that HPTH medium and SBA were more sensitive than Todd-Hewitt enrichment broth for GBS screening in pregnant women and good GBS recovery in culture, indicating that the two media should be used together for vaginal and anorectal specimens.

Detection of drug susceptibility in rapidly growing mycobacteria by resazurin broth microdilution assay.

The susceptibility of rapidly growing mycobacteria (RGM) to linezolid and ciprofloxacin was evaluated by using resazurin as a growth indicator. The assay with resazurin supplemented medium performed as well as its addition to the medium at reading time and was efficient for the determination for the susceptibility profile in RGM.

Cutaneous leishmaniasis with atypical clinical manifestations: Case report.

This case report alerts to the existence of atypical forms of cutaneous leishmaniasis (CL). A woman with nodular cutaneous lesions over a neck with papules and pustules located deep in the hypodermis that formed plaques with subcutaneous induration and satellite papules was confirmed to have CL. After confirmation, the patient was treated with remission of the lesions, scarring and thickening of the skin.

Haemophilus influenzae serotype a meningitis.

This work describes a case of Haemophilus influenzae serotype a meningitis in Brazil, after almost a decade since the introduction of Haemophilus influenzae serotype b conjugate vaccine. Uncertainty about the replacement of H. influenzae serotypes as a cause of invasive diseases justifies continuous surveillance, coupled with investigations of carriage rates and requirements of chemoprophylaxis in contact persons.