Igor Vasconcelos Rocha

Pannonibacter species. are non-fermentative Gram-stain-negative bacteria, with rare reports of human infections primarily affecting immunocompromised patients. Here, we report the genomic and phenotypic characterization of a novel Pannonibacter species, isolated from a bacteremia episode in a pediatric patient with acute lymphoblastic leukemia in Brazil. Initial characterization of the isolate (here named CBAS 1226) by MALDI-TOF mass spectrometry and 16S ribosomal RNA gene sequencing identified it as Pannonibacter sp., most closely related to P. phragmitetus. However, comparison of its MALDI-TOF spectrum with a commercial reference library revealed compatibility with only two of the five main spectra profiles for P. phragmitetus. This discrepancy motivated comprehensive genomic, biochemical, morphological, and antimicrobial resistance profiling of CBAS 1226. Genomic analysis revealed that Pannonibacter sp. CBAS 1226 is phylogenetically distinct from P. phragmitetus and other known species, with ANI and dDDH values below species delineation thresholds, supporting its proposal as Candidatus Pannonibacter alzirae. It forms small, non-hemolytic, grayish-white colonies on blood agar, similar to its closest relatives P. phragmitetus and P. indicus. Phenotypically, it is distinguished by positive α- and β-glucosidase activity, along with the utilization of citrate, L-proline, and 2-ketoglutarate. It is negative for alkaline phosphatase and unable to utilize D-fructose, D-melibiose, esculin, or L-arginine. The isolate exhibited higher MICs for β-lactams, whereas carbapenems and fluoroquinolones showed low MICs. The isolate is capable of forming biofilms and tolerates alkaline conditions, a wide range of temperatures, and different oxygen concentrations. Altogether, this report emphasizes the relevance of additional proteomics- and genomics-based approaches to clarify unusual bacterial infections and describes a new Pannonibacter species with distinct features and the potential to cause opportunistic infections.

This study reports on a multidrug-resistant (MDR) Acinetobacter baumannii isolate identified through microbiological surveillance of rectal swabs from a patient admitted to an intensive care unit (ICU) of a public hospital in Pernambuco, Brazil, in 2022. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK® automated system, and species confirmation was carried out by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of antibiotic resistance genes, including bla _KPC , bla _IMP , bla _VIM , bla _NDM , bla _SPM , bla _OXA-23 , bla _OXA-24 , bla _OXA-51 , bla _OXA-58 , and mcr-1 to mcr-10 , was investigated by polymerase chain reaction (PCR). The A. baumannii isolate exhibited resistance to all tested antimicrobials and demonstrated strong biofilm-forming capacity. Molecular analysis revealed the presence of bla _NDM-1 , bla _OXA-23 and bla _OXA-58 genes, representing a concerning genetic combination associated with carbapenem resistance. The A. baumannii isolate exhibited resistance to polymyxin B but lacked mcr-1 to mcr-10 genes. Asymptomatic colonization of MDR A. baumannii in a patient at ICU underscores the risk of possible infection that may become invasive. These findings highlight the importance of continuous microbiological surveillance to monitor the dissemination of MDR pathogens in hospital environments.

Plague, caused by Yersinia pestis, remains a historically significant and reemerging zoonotic threat worldwide. Often erroneously considered a medieval relic, the disease persists in natural foci, including Brazil, where it was introduced in 1899 via maritime trade. Over the past 125 years, the country has experienced cyclical outbreaks concentrated in the northeast, where ecological conditions support enzootic transmission among wild rodents and their fleas. While improved surveillance and control have reduced human cases in recent decades, the pathogen’s zoonotic nature and potential for rapid spread in a changing climate underscore its enduring public health relevance. Memórias do Instituto Oswaldo Cruz (MIOC), one of Latin America’s foremost tropical medicine journals, has been instrumental in documenting and shaping the course of plague research in Brazil. Its archives provide a unique chronological record, from pioneering studies on serum production and reservoir ecology to modern molecular analyses of bacterial virulence. This perspective synthesises the seminal contributions published in Memórias that have defined our understanding of plague in Brazil, identifies critical knowledge gaps that persist, and discusses emerging challenges in an era of climate change and shifting zoonotic disease dynamics.

The One Health paradigm, recognizing the inextricable link between human, animal, and environmental health, is crucial for understanding the dynamics of virulence and antimicrobial resistance (AMR). This review posits that the microbiomes of these three spheres form a connected network that acts as a unified ecosystem for the evolution and dissemination of resistant and virulent pathogens. Evidence is synthesized to demonstrate that mobile genetic elements carrying resistance and virulence genes are readily exchanged between commensals and pathogens across these niches, driven by anthropogenic pressures, particularly antibiotic use in medicine and agriculture. This exchange transforms all microbiomes into potential reservoirs and amplifiers of threat. Furthermore, dysbiosis in one reservoir, for instance, in livestock gut microbiomes due to antibiotic exposure, reverberates across the system, facilitating the emergence of multidrug-resistant zoonotic pathogens. By exploring this interconnectedness, it is highlighted that efforts to combat AMR and virulence focused solely on human clinical settings are inherently insufficient. A proactive, One Health approach is imperative, integrating surveillance across humans, animals, and the environment and developing interventions that target microbiome stability across all reservoirs to mitigate this global crisis effectively.

To assess the antibacterial effectiveness of Lippia macrophylla essential oil (LMEO) against multidrug‐resistant Acinetobacter baumannii isolates, both as a standalone treatment and in combination with conventional antibiotics. LMEO demonstrated a significant inhibitory effect on the growth of A. baumannii, with a minimum inhibitory concentration (MIC) below 500 μg/mL. Notably, LMEO was capable of reversing the antibiotic resistance of clinical isolates or reducing their MIC values when used in combination with antibiotics, showing synergistic (FICI≤0.5) or additive effects. The combination of LMEO and imipenem was particularly effective, displaying synergistic interactions for most isolates. Ultrastructural analyses supported these findings, revealing that the combination of LMEO+ceftazidime compromised the membrane integrity of the Acb35 isolate, leading to cytoplasmic leakage and increased formation of Outer Membrane Vesicles (OMVs). Taken together our results point for the use of LMEO alone or in combination as an antibacterial agent against A. baumannii. These findings offer promising avenues for utilizing LMEO as a novel antibacterial strategy against drug‐resistant infections in healthcare settings, underscoring the potential of essential oils in enhancing antibiotic efficacy.

Aims: To investigate the genetic profile and characterize antimicrobial resistance, including the main β-lactam antibiotic resistance genes, in Acinetobacterbaumannii isolates from a tertiary hospital in Recife-PE, Brazil, in the post-COVID-19 pandemic period. Methods and Results: Acinetobacter baumannii isolates were collected between 2023 and 2024 from diverse clinical samples. Antimicrobial resistance testing followed standardized protocols, with β-lactamase-encoding genes detected via PCR and sequencing. Investigation into ISAba1 upstream of blaOXA-carbapenemase and blaADC genes was also conducted. Genetic diversity was assessed through ERIC-PCR. Among the 78 A. baumannii, widespread resistance to multiple antimicrobials was evident. Various acquired β-lactamase-encoding genes (blaOXA-23,-24,-58,-143, blaVIM, and blaNDM) were detected. Furthermore, this is the first report of blaVIM-2 in A. baumannii isolates harboring either the blaOXA-23-like or the blaOXA-143 gene in Brazil. Molecular typing revealed a high genetic heterogeneity among the isolates, and multi-clonal dissemination. Conclusion: The accumulation of genetic resistance determinants underscores the necessity for stringent infection control measures and robust antimicrobial stewardship programs to curb multidrug-resistant strains.

Background and Objectives: Vancomycin-resistant Enterococcus faecium (VREf) is an opportunistic pathogen responsible for hospital infections, characterized by increasing prevalence and a lack of comprehensive epidemiological studies. We aimed to assess the occurrence of VREf and vancomycin resistance genetic elements vanA and vanB in strains isolated from clinical samples of patients treated at a tertiary hospital in Brazil. Methods: The isolates were obtained from convenience sampling according to routine medical requests for nine months. Enterococcus faecium strains were identified by routine biochemical tests, BD Phoenix® Automated Microbiology System and confirmed by MALDI-TOF Mass Spectrometry. The antimicrobial sensitivity profile was determined by disk-diffusion method and BD Phoenix®Automated Microbiology System. Vancomycin resistance was specially assessed and confirmed by the conventional microdilution technique. Molecular detection of vanA and vanB resistance genes was investigated by polymerase chain reaction (PCR) and confirmed by Sanger DNA sequencing. Results: A total of 8,376 cultures was performed, of which 19 (0.22%) were identified as Enterococcus sp. and nine (47%) as vancomycin-resistant E. faecium. The antimicrobial susceptibility testing analysis of E. faecium showed high resistance to antimicrobial agents. The analysis to determine the genetic profile of E. faecium isolates by PCR showed that all of them carried the vanA gene associated with vancomycin resistance. Conclusion: During the study period, there was low occurrence of Enterococcus species observed. However, all VREf isolates carried the vanA gene associated with vancomycin resistance and showed resistance to commonly used antimicrobial agents, highlighting concerns about the effectiveness of available antimicrobial treatments for infections caused by these isolates.

Yersinia pestis, the causative agent of plague, is a highly virulent bacterium that poses a significant threat to human health. Preserving this bacterium in a viable state is crucial for research and diagnostic purposes. This paper presents and evaluates a simple lyophilization protocol for the long-term storage of Y. pestis strains from Fiocruz-CYP, aiming to explore its impact on viability and long-term stability, while replacing the currently used methodologies. The lyophilization tests were conducted using the non-virulent Y. pestis strain EV76, subjected to the lyophilization process under vacuum conditions. Viability assessment was performed to evaluate the effects of lyophilization and storage conditions on Y. pestis under multiple temperature conditions (− 80 °C, − 20 °C, 4–8 °C and room temperature). The lyophilization protocol employed in this study consistently demonstrated its efficacy in maintaining high viability rates for Y. pestis samples in a up to one year follow-up. The storage temperature that consistently exhibited the highest recovery rates was − 80 °C, followed by − 20 °C and 4–8 °C. Microscopic analysis of the post-lyophilized cultures revealed preserved morphological features, consistent with viable bacteria. The high viability rates observed in the preserved samples indicate the successful preservation of Y. pestis using this protocol. Overall, the presented lyophilization protocol provides a valuable tool for the long-term storage of Y. pestis, offering stability, viability, and functionality. By refining the currently used methods of lyophilization, this protocol can improve long-term preservation for Y. pestis strains collections, facilitating research efforts, diagnostic procedures, and the development of preventive and therapeutic strategies against plague.

O estudo se concentra na investigação da complexidade das Infecções Relacionadas à Assistência à Saúde (IRAS) e A. baumannii por meio de uma análise crítica da literatura atual, abordando os principais fatores de risco, os mecanismos moleculares de resistência aos antimicrobianos e estratégias de prevenção e controle de disseminação. A metodologia envolveu uma revisão sistemática da literatura científica atualizada sobre o tema. Os principais achados destacam a estreita ligação entre a resistência antimicrobiana dessa bactéria e o aumento das IRAS. Mecanismos de resistência, incluindo a produção de enzimas betalactamases das classes A, B, C e D, são identificados como fatores-chave na redução da eficácia dos tratamentos, sendo esta mediada pela exposição a concentrações subinibitórias de antimicrobianos. O estudo ressalta ainda a urgência de abordagens terapêuticas e estratégias de controle para enfrentar o desafio crescente da resistência antimicrobiana, além da compreensão dos mecanismos de resistência para guiar a escolha de tratamentos eficazes e conceber medidas preventivas e de controle das IRAS. A implementação direcionada de esforços representa um fator fundamental para atenuar as ramificações da resistência antimicrobiana e proteger a saúde pública.