Revista Argentina de microbiologia最新文献

Recent advances in molecular phylogenetic and revisions to the International Code of Nomenclature have led to major changes in the fungal taxonomy. Genus Candida has been subject to extensive reclassification, with ribosomal DNA analysis demonstrating that Candida rugosa represents a cryptic species complex. Consequently, these taxa were reassigned to the novel genus Diutina. The Diutina rugosa complex includes species morphologically and physiologically indistinguishable: D. rugosa, D. mesorugosa, D. neorugosa, and D. pseudorugosa. We report the first case of D. mesorugosa diagnosed in Argentina in a 51-year-old man patient with complete spinal cord syndrome who developed osteomyelitis associated with sacrogluteal pressure ulcers. The yeast was isolated from bone tissue alongside ESBL-producing Proteus mirabilis. Fungal identification was confirmed using ribosomal DNA sequencing. D. mesorugosa is an emerging opportunistic pathogen that affects immunocompromised individuals. The patient responded favorably to a three-month course of oral fluconazole and combination antibiotic therapy (meropenem/ertapenem) for the bacterial co-infection.

The increasing presence of antibiotic-resistant bacteria in urban agriculture poses a significant public health risk. This study investigated the prevalence and virulence of methicillin-resistant Staphylococcus aureus (MRSA) in market garden environments in Bobo-Dioulasso, Burkina Faso. A total of 135 environmental samples (lettuce, irrigation water, and organic manure) were analyzed for MRSA presence using microbiological isolation, antimicrobial susceptibility testing, and molecular characterization. Among 55 Staphylococcus isolates, 16 (32.7%) were confirmed as MRSA, with PVL detected in 18.4% and TSST-1 in 6.1%. High resistance rates to oxacillin (96.4%) and fusidic acid (69.1%) highlight the need for targeted antimicrobial stewardship. Statistical analyses were conducted using R (version 2.10.0), applying Chi-square, ANOVA, Kruskal-Wallis, and logistic regression tests to assess variations in antibiotic resistance and predictive factors in environmental samples, with significance set at p<0.05. These findings underscore the necessity for enhanced microbial surveillance, improved hygiene protocols, and policy interventions to mitigate foodborne risks associated with urban agriculture.

Globicatella is a genus of catalase-negative, facultative anaerobes, and non-hemolytic Gram-positive cocci, arranged in pairs or in short chains. Twenty-five positive urine cultures, mainly obtained by catheterization, and two urinary stone cultures due to Globicatella spp. were retrospectively recorded from patients between January 1, 2014 and October 31, 2024. Isolates were identified by mass spectrometry (Vitek MS), 16S rRNA gene sequencing and biochemical tests. Most patients had complex uropathies or congenital malformations of the urinary tract. A high percentage of the isolates showed high ceftriaxone (CRO) MICs (MIC50 and MIC90: 2-16μg/ml) and almost half of them had low penicillin (PEN) MICs (MIC50 and MIC90: 0.25 and 2μg/ml). The present study is the most extensive report of Globicatella urinary tract infections in children.

The poultry industry represents an important economic sector in Argentina. In this study we recovered 26 vancomycin-resistant Enterococcus (VRE) isolates from different productive stages of a poultry farm located in Tandil, Argentina. Ten isolates were Enterococcus faecium and seven, Enterococcus faecalis. Total resistance to vancomycin (96.2%), erythromycin (80.8%), levofloxacin (57.7%), chloramphenicol (26.7%), penicillin (23.1%), ampicillin (7.7%) was detected and 20 isolates (76.9%) were identified as multidrug-resistant (MDR). With respect to the distribution of glycopeptide resistance genes, 57.7% of the isolates harbored the vanC-1 gene, and 11.5%, carried the vanC-2/C-3 gene. The vanA and vanB variants were not detected. This study provides evidence that healthy chickens from the studied region can be a reservoir of MDR-VRE. Further surveillance should be conducted to control their dissemination through the food chain.

Standardized doses such as defined daily doses (DDDvet) and defined course doses (DCDvet) are essential to quantify the antimicrobials (AMs) used in veterinary medicine as a prior step for determining strategies for their responsible use. Therefore, the aim of this study was to create a list of the available intramammary formulations for mastitis and drying off in Argentina, and to estimate their DDDvet and DCDvet. DDDvet and DCDvet were determined for 29 mastitis cases and 27 drying formulations. Critically important AM formulations of the highest priority for human health (ceftiofur or cefquinome) were identified. In addition, there were combined formulations with up to four different AMs, including critically important AMs. The results of this study show a high diversity of formulations and concentrations, low availability of mono-drug products, and a high proportion of combinations that include AMs considered essential for human health. These findings highlight the urgent need to standardize dosages in Argentina, prioritize the use of AMs of low medical importance, and promote the prudent and rational use of these drugs, in line with a One Health approach.

The spontaneous coffee fermentation process can be regulated through the application of microbial starter cultures, which are used to enhance the quality of the coffee. In this study, microorganisms derived from coffee fermentations conducted on a representative farm in Southwestern Colombia, where specialty export-type coffee is produced, were isolated, characterized, and identified. The methodology used was based on cultivation techniques of key microbial groups in coffee fermentation, which enabled to establish a collection of microorganisms with future applications in postharvest coffee processing. The microorganisms that exhibited significant characteristics within the established criteria of this study, which were used for the selection of starter cultures for coffee fermentation, belonged to microbial genera or species that are commonly found during the coffee fermentation process. Consequently, the strains Acetobacter tropicalis m108, Kosakonia cowanii P121, Leuconostoc mesenteroides M154, L. mesenteroides M159, Lactiplantibacillus plantarum M157, Pichia kluyveri Y144, P. kudriavzevii Y150, Wickerhamomyces anomalus Y149, and Rhodotorula mucilaginosa Y147 were selected for further study. These strains represent a valuable genetic resource that could contribute to enhancing the quality of coffee from the region, particularly in regard to its cup quality, for future use as starter cultures.

Hepatitis A virus (HAV) has a low endemic circulation pattern in Argentina. Clinical cases mainly occurred in susceptible young adults, with recent outbreaks reported. The aim of this study was to provide updated information on the HAV immune status of the adult population from Central Argentina. A retrospective analysis was conducted, recording the results of anti-HAV IgG in 4235 samples of individuals without prior vaccination from Córdoba, Argentina (2019 and 2022). Epidemiological data recorded included sex, age, HIV status and income level. The overall prevalence of anti-HAV was 70.1%, increasing with age as follows: 52.6% among the 18-25-year-old group, 53.8% in 26-35-year-old young adults, 67.4% in 36-45-year old adults, and >80% in the >46-year-old group. Moreover, prevalence was associated with low-income populations and was significantly higher among female patients (p<0.0001). Considering the high proportion of young adult individuals susceptible to HAV infection identified, along with evidence of HAV circulation in the region - which can be easily introduced by unvaccinated immigrants or travelers from medium/high endemic countries - and the existence of a safe, efficient vaccine, we strongly recommend further investigating HAV immunity in individuals over 18 years old in our region. For those testing negative, vaccination is recommended.

Rift Valley fever is a mosquito-borne disease caused by the Rift Valley Fever Virus (RVFV) belonging to the genus Phlebovirus. This virus causes febrile or hemorrhagic illness in humans and ruminants, such as abortion, and death; especially in young sheep, cattle, and goats resulting in devastating epidemics in Africa and the Arabian Peninsula. The WHO has included this virus in Bluepoint's list of eight pathogens. This virus is a crucial health concern in the Kingdom of Saudi Arabia (KSA), as the Kingdom is regularly exposed to this virus from the original source of East African countries. A complete understanding of viral pathogenesis, epidemiology, antiviral therapeutics, and human vaccines is still lacking. This review aims to provide an update on the status, pathogenesis, prevalence, challenges, and future prospects of RVFV in the KSA. The information provided will aid in the design and development of disease management strategies and novel prophylactic and therapeutic measures to control the infection and disease progression of RVFV in both humans and animals.

Clostridioides difficile is an etiological agent of diarrhea, and the use of antibiotics is one of the main risk factors for infection. Antimicrobials used for treatment are vancomycin (VAN), metronidazole (MET), and fidaxomicin. Resistant strains have been detected, exhibiting regional and institutional differences. The aim of this work was to determine the susceptibility profile of C. difficile clinical isolates to 14 antimicrobials, and to compare resistance among participating centers. A total of 208 consecutive isolates recovered from seven Argentinian hospitals between January 2018 and March 2020 were studied. MIC was determined by the agar dilution method (CLSI-M100 29ED). Azithromycin (AZM), clindamycin (CLI), ertapenem (ETP), imipenem (IMI), levofloxacin (LEV), linezolid (LNZ), meropenem (MER), metronidazole (MET), moxifloxacin (MOX), piperacillin-tazobactam (PTZ), rifaximin (RFX), teicoplanin (TEI), tigecycline (TGC), and VAN, were tested. The results were analyzed with SPSS 21.0. Chi-square was used to compare data, and statistical significance was set at p<0.05. Susceptibility percentages were as follows: VAN, TEI, and MET, 100%; TGC, 97.6%; PTZ, 96.2%; LNZ, 95.2%; MER, 99.5%; ETP, 60.9%; IMI, 42.8%; RFX, 55.6%; LEV, 48.6%; MOX, 46.1%; CLI, 29.9%; and azithromycin, 17.8%. Significant differences in resistance among centers were observed for: RFX (16.7%-91.7%), CLI (41.2%-86.1%), MOX (22.9%-97.2%), IMI (0%-55.6%), and azithromycin (62.5%-97.2%). Multidrug resistance (MDR) was detected in 80 isolates (38.5%), of which 63 (78.7%) were resistant to three families of antimicrobial agents and 17 (21.3%) were resistant to four. The most frequent combinations were RFX-MOX-CLI, present in 48 (60.0%) isolates, and RFX-IMI-MOX-CLI in 17 (21.3%) isolates. VAN, TEI, and MET were the most active antimicrobials in vitro against C. difficile strains. MER was the most active carbapenem, whereas IMI was the least active. We highlight the differences across institutions that could reflect epidemiological characteristics, and/or the dissemination of clones in each institution.

Basmati rice is in high demand in the world market because of its fine, soft, long and distinctive aromatic grains. Bacterial leaf blight (BLB), caused by Xanthomonas oryzae pv. oryzae, is a destructive disease, resulting in enormous yield loss in basmati rice. Chemical management against BLB is effective but not the preferred approach because of its detrimental effects on humans, environment and ecological disruption. In the present study, seed treatment, seedling treatment and foliar application with microbial antagonists, such as Trichoderma harzianum and Pseudomonas fluorescens, and a consortium encompassing both microorganisms plus Trichoderma asperellum, were assessed against BLB in basmati rice. Among all the bio-formulation treatments, seed treatment with the microbial consortium revealed significant (p<0.05) results, achieving maximum inhibition of BLB incidence, intensity and lesion length of 48.56, 52.42 and 45.41 percent respectively, compared to the untreated control. Simultaneously, the same treatment also resulted in significant (p<0.05) enhancement of growth attributes, such as panicle length (55.83%), plant fresh weight (15.55%), grains per panicle (38.23%), test weight (55.49%) and yield (47.68%). A maximum increase in superoxide dismutase and hydrogen peroxide activities by 81.58 and 84.29 percent respectively over the control was also recorded. The results of the study suggest that the effectiveness of BLB management under field conditions applying the microbial consortium (T. harzianum+T. asperellum+P. fluorescens) was similar to that of the chemical control. Further, efforts are being made to evaluate the biocontrol activity of the microbial consortium in large-scale field experiments and its commercial potential.