Revista Argentina de microbiologia最新文献

Biofilm-associated microorganisms can cause many infections and are an important cause of resistance to several antimicrobials. The antibiotic crisis has led to a pressing need for new therapeutic tools. Ambroxol is frequently used as a mucolytic agent in respiratory diseases with increased mucus production. In addition, a wide range of properties has been described, including the effect on biofilms. In this work, we evaluate the anti-biofilm effect of ambroxol on four strains with clinical relevance: Proteus mirabilis, Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii. In vitro, biofilm formation was assessed using the crystal violet quantification technique in microplate and glass coverslip. The inhibition of biofilm formation was evaluated by adding ambroxol at the initial time. Ambroxol hydrochloride was evaluated over the preformed biofilm and live/dead bacteria were quantified. The effect of ambroxol in the ethidium bromide efflux assay and the relative expression of the five major P. mirabilis efflux pump family genes were analyzed. Ambroxol inhibited biofilm formation in all the bacteria tested. Moreover, ambroxol significantly reduces both biofilm biomass and viable bacteria. Ambroxol was able to affect P. mirabilis efflux pumps depending on the concentration used and induced the overexpression of several efflux pump genes. In summary, ambroxol kills planktonic cells, reduce biofilm biomass as it increases cell death, and affect the expression of efflux pumps. Furthermore, it presents a viable alternative for the treatment of biofilm infection alone or in combination with antibiotic therapy.

Given the importance of the coastal environments and the multiple ecological services that they provide, it is important to explore and understand the interactions that occur within them. The microbiome is a key factor for the understanding of the dynamics of these fragile sites. A metagenomic study based on the profiling of the 16S ribosomal gene was carried out in order to assess the bacterial diversity present in the northern coastal zone of the Yucatan Peninsula. The results showed that water and sediment samples share some similarities regarding the bacterial genera found, only differing in the quantitative part. Through a PCO (principal coordinates) analysis clear differences between sediment and water samples could be observed. The highest relative diversity was found in wetland and lagoon sediment samples, respectively. It was observed that 3-8% of the total sequence reads belonged to opportunistic genera such as: Vibrio in the sea samples and Capnocytophaga in the other environments. Salinity and pH were the factors which contributed the most to the differences among the communities in the various environments in the coastal zone. There is an important similarity in the sediments across the different environments within the studied coastal zone. The data presented herein contribute to setting a baseline for research in the coastal region of the Yucatan Peninsula.

Infectious diarrhea is a common health issue that affects a large number of individuals each year. It causes significant morbidity and mortality, greatly impacting healthcare system costs. Rapid detection of the causative organism and timely treatment alters the management and outcome of the condition. Molecular panels in stool allow to analyze a wide range of pathogens quickly and easily. For this study, a cross-sectional cohort analysis with a retrospective analysis of adult patients hospitalized with diarrhea and negative conventional stool bacteriological studies was conducted. Data obtained from the use of molecular panels in stool and the role of endoscopy in the diagnostic pathway were analyzed. A positivity rate of 52% (n=41) out of a total of 79 samples was reported. The test contributed to a change in therapeutic approach in 58% (n=46) of the patients. Among the patients with a negative molecular panel, 39.5% underwent further evaluation with colonoscopy involving biopsies, resulting in a diagnostic yield of 87%. Based on these results, we can conclude that molecular techniques contribute to the diagnosis and change in therapeutic approach in hospitalized patients with diarrhea.

Brucellosis is a zoonotic disease with a worldwide distribution that causes significant productive losses and negative impacts on public health. The aim of this work was to identify the risk factors associated with the presence of brucellosis in mixed farms (cattle/goats) in the central-western region of the province of Formosa. Sixty seven mixed farms with 7,855 animals (2,943 cattle and 4,912 goats) were randomly sampled during 2022/2023. The samples were serologically analyzed (BPA + FPA) to determine which animals were positive. Likewise, in each farm, a confidential survey was carried out to evaluate potential associated variables. The statistical analysis was performed using Generalized Linear Mixed Models (GLMM) with binomial distribution, logarithmic link function, and farm as a random variable. The estimated prevalence of brucellosis in mixed farms was 9%, while the joint prevalence per animal (cattle and goats) was 2.75%. The prevalence of brucellosis in cattle and goats was explained by the presence of animals with reproductive signs (odds ratio, OR=40), the occurrence of abortions in the last term of gestation and the birth of weak offspring (OR=5.3), incorrect treatment of abortions (OR=8), the introduction of animals from other farms (OR=5.9), and not having a negative brucellosis certificate (OR=9.6). The management practices conducted in each farm such as preventive measures, sanitation practices for the pens, and prevention measures for the workers, are important for the control of brucellosis.

We describe here the first isolation in Argentina of a lactose-fermenting and lysine decarboxylase-negative non-Typhi Salmonella enterica from a blood culture of a patient with systemic lupus erythematosus. The microorganism was identified as S. enterica (score: 2.148) by mass spectrometry, as "Salmonella group" (discrimination: 86%) by the VITEK® 2 system and as Citrobacter freundii complex by biochemical tests. The serological test using the OMA antiserum for the somatic antigen was positive. The identification was confirmed as Salmonella subsp. I 4,[5],12:i:- atypical at the National Reference Center ANLIS Dr. Carlos G. Malbrán. Mass spectrometry is especially useful in microbial identification in the presence of atypia, while biochemical tests can lead to misidentification in these cases. This study warns about the circulation of this strain in Argentina.

In 2021, avian influenza A (H5N1) clade 2.3.4.4b virus spread to North America and then to Central and South America in October 2022, extending from Colombia to Chile in three months. During 2023, several countries, mostly in the Americas, reported outbreaks in poultry, wild birds and mammals, as well as the emergence of two cases in humans (one in Ecuador in January and one in Chile in March). As of September 20th, 2023, 17 countries in the Americas Region have recorded cases of A (H5N1) in birds and mammals. On February 14th, 2023, Argentina confirmed the first case of avian influenza in wild birds, which was later detected in backyard and commercial poultry, and in the South-American sea lion (Otaria flavescens) in Tierra del Fuego, in the south of the country. So far, 21 suspected cases have been recorded in humans; however, all of them tested negative for Influenza A virus. Hemagglutinin sequence data of animal viruses analyzed in this report showed that Argentinian viruses clustered together with those isolated in other countries of the region. Epidemiological data suggested the possibility of multiple simultaneous entries of the avian virus, highlighting the role of migratory avian populations in the introduction and dissemination of the disease in Argentina. Continued comprehensive surveillance of these viruses in animals and people worldwide, along with ongoing preparedness efforts, are critical to determine the public health risk.