2025
Antimicrobial Susceptibility of Escherichia coli Isolates Causing Community-Acquired Urinary Tract Infections: Comparison of Methods
Due to bacterial resistance to antimicrobials, antibiotic therapy for urinary tract infections (UTIs) has become a major challenge for clinicians. The present work aimed to compare the antimicrobial susceptibility profiles of 53 uropathogenic Escherichia coli (UPEC) isolates, assessed using the disk diffusion method and two automated systems (PHOENIX BD™ and VITEK2), with interpretations based on CLSI and BrCAST guidelines. Twenty-five antibiotics were tested to assess differences in susceptibility profiles. Statistical tools, including Kappa coefficient analysis and chi-square tests, were applied to assess concordance and significance between methods. Among the main discrepancies found, BrCAST has classified a greater number of UPEC isolates as resistant to more than half of the antibiotics tested by the disk diffusion method, when compared to CLSI. Although faster, the PHOENIX BD and VITEK2 automated systems exhibited significant discrepancies, with divergences observed for half of the antimicrobials tested. Both automated methods showed discrepancies compared to the disk diffusion method under CLSI and BrCAST guidelines. PHOENIX BD classified some isolates resistant by DD/CLSI as susceptible, while VITEK2 misclassified 25% to 50% of the antimicrobials tested. Conversely, VITEK2 also classified some isolates susceptible to DD/CLSI as resistant to 25% of the antimicrobials tested. Regarding DD/BrCAST, PHOENIX BD classified resistant isolates as susceptible (to 50% of the antimicrobials tested). In comparison, VITEK2 classified resistant isolates as susceptible and susceptible isolates as resistant (25% of the antimicrobials for both). These findings highlight the need for careful selection of susceptibility testing methods, as variations in interpretive criteria between CLSI and BrCAST could impact clinical decision-making. This study underscores the importance of methodological consistency in accurately informing antibiotic therapy in UTI management, especially in the face of rising resistance.
Link para o artigo completo: https://www.mdpi.com/2076-2607/13/2/231
2024
Candida spp. isolated from recreational coastal waters of Rio de Janeiro – Brazil: Focus on antifungal resistance and virulence attributes
The use of recreational waters is a widespread activity worldwide, and one of the risks associated with this practice is the exposure of bathers to microorganisms that may arise due to pollution caused by inadequate infrastructure and sanitation. In the present work, we isolated Candida spp. (n = 24) from five recreational beaches in Rio de Janeiro, Brazil, in order to evaluate their susceptibility to antifungals, the production of virulence attributes and the in vivo virulence using Tenebrio molitor larvae as a model. The ITS1–5.8S-ITS2 gene sequencing identified thirteen isolates (54.1 %) as C. tropicalis, seven (29.1 %) as C. krusei (Pichia kudriavzevii), one (4.2 %) as C. rugosa (Diutina rugosa), one (4.2 %) as C. mesorugosa (Diutina mesorugosa), one (4.2 %) as C. utilis (Cyberlindnera jadinii) and one (4.2 %) as C. parapsilosis. C. tropicalis isolates showed resistance to azoles and susceptibility to amphotericin B, flucytosine and caspofungin. C. krusei isolates were resistant to fluconazole, caspofungin and itraconazole, with 42.8 % resistance to flucytosine, besides susceptibility to voriconazole and amphotericin B. The remaining species were susceptible to all tested antifungals. All Candida isolates adhered to abiotic surfaces and formed biofilm on polystyrene, albeit to varying degrees, and produced aspartic protease and hemolytic activity, which are considered fungal virulence attributes. C. tropicalis, C. krusei and C. utilis isolates produced phytase, while the only esterase producer was C. tropicalis. Regarding resistance to osmotic stress, all isolates of C. tropicalis, C. parapsilosis and C. mesorugosa grew up to 7.5 % NaCl; the remaining isolates grew up to 1.87–3.75 % NaCl. The mortality caused by fungal challenges in T. molitor larvae was variable, with C. tropicalis, C. utilis and C. parapsilosis being more virulent than C. krusei and C. rugosa complex. Collectively, the presence of these yeasts, particularly the virulent and resistant isolates, in recreational waters can pose a significant health risk to bathers.
Link para o artigo completo: https://www.sciencedirect.com/science/article/pii/S0048969724048113
Evaluation of the feasibility for replacing sheep blood with human blood in culture media used in microbiological diagnostics
The present study aimed to suggest the replacement of animal blood with human blood in culture media, involving alternative methods and ethical considerations, such as animal welfare, in addition to potential laboratory cost reduction. Characteristics of growth and hemolysis development were compared in different culture media, using both sheep blood and human blood. Blood types from the ABO blood group system were tested, and commercially acquired sheep blood agar was used for comparison. Bacteria of the genus Streptococcus spp., Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli were tested. It was observed that growth in media with type A and O positive blood showed closer similarities to those performed in agar with sheep blood. Depending on the bacterial species, the results were either more positive or not, with faster-growing and less demanding bacteria showing better results than, for example, S. pneumoniae, which demonstrated difficulty in the growth process and hemolysis generation in human blood agar. The research suggests that in some situations, sheep blood could be replaced, especially when the goal is growth and isolation, but may not be as suitable when the objective is to analyze hemolysis or when the studied species is demanding.
Link para o artigo completo: https://doi.org/10.1590/0001-3765202420231168
2023
Long-Term Co-Circulation of Host-Specialist and Host-Generalist Lineages of Group B Streptococcus in Brazilian Dairy Cattle with Heterogeneous Antimicrobial Resistance Profiles
Group B Streptococcus (GBS) is a major cause of contagious bovine mastitis (CBM) in Brazil. The GBS population is composed of host-generalist and host-specialist lineages, which may differ in antimicrobial resistance (AMR) and zoonotic potential, and the surveillance of bovine GBS is crucial to developing effective CBM control and prevention measures. Here, we investigated bovine GBS isolates (n = 156) collected in Brazil between 1987 and 2021 using phenotypic testing and whole-genome sequencing to uncover the molecular epidemiology of bovine GBS. Clonal complex (CC) 61/67 was the predominant clade in the 20th century; however, it was replaced by CC91, with which it shares a most common recent ancestor, in the 21st century, despite the higher prevalence of AMR in CC61/67 than in CC91, and high selection pressure for AMR from indiscriminate antimicrobial use in the Brazilian dairy industry. CC103 also emerged as a dominant CC in the 21st century, and a considerable proportion of herds had two or more GBS strains, suggesting poor biosecurity and within-herd evolution due to the chronic nature of CBM problems. The majority of bovine GBS belonged to serotype Ia or III, which was strongly correlated with CCs. Ninety-three isolates were resistant to tetracycline (≥8 μg/mL; tetO = 57, tetM = 34 or both = 2) and forty-four were resistant to erythromycin (2.0 to >4 μg/mL; ermA = 1, ermB = 38, mechanism unidentified n = 5). Only three isolates were non-susceptible to penicillin (≥8.0 μg/mL), providing opportunities for improved antimicrobial stewardship through the use of narrow-spectrum antimicrobials for the treatment of dairy cattle. The common bovine GBS clades detected in this study have rarely been reported in humans, suggesting limited risk of interspecies transmission of GBS in Brazil. This study provides new data to support improvements to CBM and AMR control, bovine GBS vaccine design, and the management of public health risks posed by bovine GBS in Brazil.
Link para o artigo completo: https://www.mdpi.com/2079-6382/13/5/389
Impact of human created environments in the pathogenic potential and antimicrobial resistance of staphylococci from wild neotropical primates in Brazil
Importance
Link para o artigo completo: https://www.sciencedirect.com/science/article/pii/S0147957123001522
Prevalence, capsular types, antimicrobial resistance and risk factors associated with pneumococcal carriage among children after long-term 10-valent pneumococcal conjugate vaccine use in Brazil
Background
Methods
Results
Conclusions
Link para o artigo completo: https://www.sciencedirect.com/science/article/pii/S0264410X23004152
High Incidence of Respiratory Syncytial Virus in Children with Community-Acquired Pneumonia from a City in the Brazilian Pre-Amazon Region
Link para o artigo completo: https://www.mdpi.com/1999-4915/15/6/1306
Effects of Euterpe oleracea Mart. extract on Candida spp. biofilms
Problem of research
Candida spp. biofilms are complex microbial communities that have been associated with increasing resistance to clinically available antifungal drugs. Hence, novel pharmacological approaches with ability to inhibit biofilm formation have been investigated.
Aim of study
The aim was to analyze in vitro antifungal activity of Euterpe oleracea Mart. (açaí berry) extract on biofilm strains of Candida albicans, C. parapsilosis, and C. tropicalis that were formed on abiotic surfaces.
Remarkable methodology
Biofilms of C. albicans, C. parapsilosis, and C. tropicalis were grown in vitro. They were then treated with E. oleracea Mart. extract at different concentrations (7.8, 15.6, 31.2, 62.5, 125, 250, 500, and 1000 μg/mL) for evaluation of both biofilm removal and anti-biofilm activity.
Remarkable results
All Candida species analyzed formed biofilms on abiotic surfaces. Yet, increased biofilm formation was displayed for C. tropicalis in comparison with the other two species. E. oleracea Mart. extract was shown to inhibit biofilm formation at all concentrations used when compared to no treatment (p < 0.05).
Significance of the study
In the current study, the extract of E. oleracea Mart. demonstrated antifungal activity against Candida albicans, C. parapsilosis, and C. tropicalis biofilms, regardless of the dose utilized. These results are important to evaluate a natural product as antifungal for Candida species.
Link para o artigo completo: https://link.springer.com/article/10.1007/s42770-023-00919-1
Systemic infection caused by the methicillin-resistant Staphylococcus aureus USA300-LV lineage in a Brazilian child previously colonized
The methicillin-resistant Staphylococcus aureus (MRSA) USA300-Latin American variant (USA300-LV) lineage is well documented in northern Latin American countries. It has replaced established clones in hospital environments. We herein report a systemic infection caused by a USA300-LV isolate in a 15-year-old boy, from a low-income area of Rio de Janeiro, previously colonized by the same strain. During hospital stay, seven pvl-positive MRSA USA300-LV isolates were recovered by nasal swab, blood and abscess secretion. The patient underwent intravenous vancomycin, daptomycin, and oral sulfamethoxazole/trimethoprim, and was discharged after 45 days after full recovery. This is the first documented case of a community-acquired MRSA infection caused by the USA300-LV variant in Brazil in a previously colonized adolescent with no history of recent travel outside of Rio de Janeiro. The need for improved surveillance programs to detect MRSA colonization in order to control the spread of hypervirulent lineages among community and hospital settings is highlighted.
Link para o artigo completo: https://www.sciencedirect.com/science/article/pii/S1413867022004305
2022
Identificação e perfil de susceptibilidade de Aeromonas sp. isoladas de Estações de Tratamento de Esgoto utilizando meio cromogênico com antimicrobiano
O gerenciamento de resíduos deve ser realizado corretamente, caso contrário, há o aumento de casos de doenças infectocontagiosas e até mesmo o impacto ambiental. Micro-organismos potencialmente patogênicos podem estar presentes no esgoto, causando uma série de infecções e como consequência, efeitos deletérios à saúde humana e até o óbito. É o caso do gênero Aeromonas, que embora seja tolerável dentro dos padrões de potabilidade da água, pode causar diversas doenças em homens e animais e ainda disseminar genes de resistência nesse tipo de ambiente. O objetivo do presente trabalho foi identificar a presença de Aeromonas sp. isoladas em Estações de Tratamento de Esgoto (ETE), utilizando meio cromogênico com cefalosporina de terceira geração e realizando posteriormente o Teste de Sensibilidade aos Antimicrobianos (TSA). A Estação Central e a Estação INI (Instituto Nacional de Infectologia), ambas localizadas na Fundação Oswaldo Cruz, foram eleitas para a realização do estudo. A semeadura foi diretamente da amostra em CHROMagar ESBL e após enriquecimento da mesma em BHI, foi realizada nova semeadura no meio cromogênico citado. A identificação, após triagem, foi baseada em provas bioquímicas, seguida pelo TSA baseado nos compêndios atualmente aceitos. Foram identificados 28 isolados Aeromonas hydrophila (16), Aeromonas caviae (9) e Aeromonas sobria (3), resistentes a cefotaxima (presente no meio seletivo), porém 75% não-sensíveis a ciprofloxacino, 71% a ceftriaxona, 57% a ceftazidima, 46% a cefoxitina, 36% a cefepime, 28% a piperacilina+tazobactam e 11% a gentamicina. Os resultados apresentaram baixa resistência dos isolados testados apesar de já crescerem em meio seletivo com antimicrobiano. Entretanto, apresentou frequência aumentada em praticamente todas as amostras, ressaltando a preocupação com infecções relacionadas a este gênero. O meio cromogênico utilizado otimizou a triagem de Aeromonas sp., fazendo com que o mesmo seja de grande importância também em amostras ambientais.
Link para o artigo completo: https://www.arca.fiocruz.br/handle/icict/55087
A simple disk pre-diffusion test to predict in vitro aztreonam/avibactam activity against NDM-producing Klebsiella pneumoniae complex
Objectives
Methods
Results
Conclusion
Link para o artigo completo: https://www.sciencedirect.com/science/article/pii/S2213716521002836
2021
Application of Green Surfactants in the Remediation of Soils Contaminated by Hydrocarbons
Among the innovative technologies utilized for the treatment of contaminated soils, the use of green surfactants appears to be a biocompatible, efficient, and attractive alternative, since the cleaning processes that normally use synthetic surfactants as additives cause other problems due to toxicity and the accumulation of by-products. Three green surfactants, i.e., two biobased (biobased 1 and biobased 2) surfactants produced by chemical synthesis and a microbial surfactant produced from the yeast Starmerella bombicola ATCC 22214, were used as soil remediation agents and compared to a synthetic surfactant (Tween 80). The three surfactants were tested for their ability to emulsify, disperse, and remove different hydrophobic contaminants. The biosurfactant, which was able to reduce the water surface tension to 32.30 mN/m at a critical micelle concentration of 0.65 g/L, was then used to prepare a commercial formulation that showed lower toxicity to the tested environmental bioindicators and lower dispersion capacity than the biobased surfactants. All the green surfactants showed great emulsification capacity, especially against motor oil and petroleum. Therefore, their potential to remove motor oil adsorbed on different types of soils (sandy, silty, and clay soil and beach sand) was investigated either in kinetic (flasks) or static (packed columns) experiments. The commercial biosurfactant formulation showed excellent effectiveness in removing motor oil, especially from contaminated sandy soil (80.0 ± 0.46%) and beach sand (65.0 ± 0.14%) under static conditions, while, in the kinetic experiments, the commercial biosurfactant and the biobased 2 surfactant were able to remove motor oil from all the contaminated soils tested more effectively than the biobased 1 surfactant. Finally, the S. bombicola commercial biosurfactant was evaluated as a soil bioremediation agent. In degradation experiments carried out on motor oil-contaminated soils enriched with sugarcane molasses, oil degradation yield in the sandy soil reached almost 90% after 60 days in the presence of the commercial biosurfactant, while it did not exceed 20% in the presence of only S. bombicola cells. These results promise to contribute to the development of green technologies for the treatment of hydrophobic pollutants with economic gains for the oil industries.
Link para o artigo completo: https://www.mdpi.com/2227-9717/9/9/1666
Avaliação de microorganismos presentes em aparelhos celulares utilizados por profissionais de saúde: um estudo realizado em um hospital da Baixada Fluminense (RJ)
Objetivo: Investigar as bactérias presentes nos aparelhos dos profissionais de saúde que atuam em quatro áreas distintas do hospital: Unidade de Terapia Intensiva (UTI), Centro Cirúrgico, Emergência e recintos estritamente administrativos, este último constitui o grupo de controle. Métodos: Foi realizado um estudo transversal aplicado em um hospital a partir de 120 amostras coletadas dos telefones celulares de profissionais que atuam em setores de especialidades distintas. Para isso, seus swabs foram cultivados em meio Ágar em placas de cultura e suas leituras realizadas em 24 e 48h, os resultados então foram diferenciados em conformidade com as especialidades. Resultados: Do total de aparelhos (120) avaliados, 92,5% (111) estavam colonizados por um ou mais tipos de bactérias. O tipo de bactéria mais frequente foi o Staphylococcus coagulase-negativa (51%), seguido do Staphylococcus aureus MRSA (6%), Acinetobacter baumannii (3,3%) e Klebsiella pneumoniae (1,6%). Conclusão: Como identificado em outros estudos que confirmaram a contaminação de aparelhos celulares de profissionais no ambiente hospitalar, estes dispositivos podem servir como agentes carreadores de bactérias potencialmente patogênicas. Isto posto, medidas para regulamentar seu uso e a necessidade de revisão dos protocolos de higiene fazem-se indispensáveis.
Link para o artigo completo: https://acervomais.com.br/index.php/saude/article/view/6295
2020
Difficulty in detecting low levels of polymyxin resistance in clinical Klebsiella pneumoniae isolates: evaluation of Rapid Polymyxin NP test, Colispot Test and SuperPolymyxin medium
Polymyxins are important therapeutic options for treating infections, mainly those caused by carbapenem-resistant Klebsiella pneumoniae. Specific chemical characteristics of polymyxins make it difficult to perform antimicrobial susceptibility testing, especially within the clinical laboratory. Here we aimed to evaluate the performance of three phenotypic methods: Rapid NP Polymyxin Test, ColiSpot test and the SuperPolymyxin medium. To accomplish this, 170 non-duplicate clinical K. pneumoniae isolates were analysed (123 colistin-resistant and 47 susceptible). The sensitivity and specificity obtained for Rapid Polymyxin NP Test, Colispot and SuperPolymyxin medium were, respectively, 90% and 94%, 74% and 100%, and 82% and 85%. Very major errors occurred more frequently in low-level colistin-resistant isolates (MICs 4 and 8 μg/mL). Rapid Polymyxin NP proved to be a method capable of identifying colistin-resistant strains in acceptable categorical agreement. However, major errors and very major errors of this method were considered unacceptable for colistin-resistance screening. Although the Colispot test is promising and easy to perform and interpret, the results did not reproduce well in the isolates tested. The colistin-containing selective medium (SuperPolymyxin) showed limitations, including quantification of mucoid colonies and poor stability. Nevertheless, Colispot and SuperPolymyxin medium methods did not present acceptable sensitivity, specificity and categorical agreement. It is essential to use analytical tools that faithfully reproduce bacterial resistance in vitro, especially in last-line drugs, such as polymyxins, when misinterpretation of a test can result in therapeutic ineffectiveness.
Link para o artigo completo: https://www.sciencedirect.com/science/article/pii/S2052297520300743
Detection of Drug Resistant Mycobacterium Tuberculosis Strains Using Kit SIRE Nitratase®: a Multicenter Study
(1) Background: The Commercial Kit SIRE Nitratase® PlastLabor, is a drug susceptibility test kit used to detect Mycobacterium tuberculosis resistance to first-line TB treatment drugs. The present study aimed at evaluating its performance in a multicenter study.
(2) Methods: To determine its accuracy, the proportion methods in Lowenstein Jensen medium or the BACTECTMMGITTM960 system was used as a gold standard.
(3) Results: The study revealed that the respective accuracies of the kit with 190 M. tuberculosis clinical isolates, using the proportion methods in Lowenstein Jensen medium or BACTECTMMGITTM960 system as a gold standard, were 93.9% and 94.6%, 96.9% and 94.6%, 98.0% and 97.8%, and 98.0% and 98.9%, for streptomycin, isoniazid, rifampicin, and ethambutol, respectively.
(4) Conclusion: Thus, the kit can rapidly screen resistance to streptomycin, isoniazid, rifampicin, and ethambutol. Additionally, it does not require sophisticated equipment; hence, it can be easily used in the laboratories of low and middle income countries.
Link para o artigo completo: https://doi.org/10.1590/1678-4324-2020190179