Revista Argentina de microbiologia最新文献

Bacillus species are of great interest due to their ability to produce lipopeptides with antifungal properties against various plant pathogenic fungi. The aim of this study was to evaluate the inhibitory effect of a lipopeptide extract from Bacillus amyloliquefaciens B17 on the mycelial growth and spore germination of the fungus Gilbertella persicaria, as well as to identify the compounds responsible for the antifungal activity. Scanning electron microscopy revealed that the lipopeptide extract caused abnormal bulges in the hyphae and malformations in the germ tubes. Additional analyses showed increased permeability in both the mycelium and spores, attributed to the action of the lipopeptides. Thin-layer chromatography (TLC) combined with mass spectrometry (ESI-MS) identified a total of eleven homologs corresponding to fengycin A, fengycin B, bacillomycin D, and surfactin in the extract. These findings suggest that the lipopeptide extract from B. amyloliquefaciens B17 represents a promising tool for the biological control of G. persicaria.

Human papillomavirus infection is the most common sexually-transmitted infection and its relationship with vaginal microbiota is not entirely clear. The aims of this study were: (1) to determine the prevalence of infection with high-risk (hr)-HPV types in different age groups; (2) to describe the hr-HPV types according to the grade of cervical squamous intraepithelial lesion (SIL); (3) to establish the prevalence of bacterial vaginosis (BV), yeasts and trichomoniasis in the different age groups studied according to the type of hr-HPV detected. A total of 741 patients underwent clinical examination and collection of vaginal fornix to study basic vaginal states (BVS) and culture. hr-HPV types were determined using multiple isothermal real-time amplification. Patients were divided into three age groups: Group 1, 18-24 years (n=138), Group 2, 25-50 years (n=456) and Group 3, over 50 years (n=147). All groups were further divided into HPV-negative, HPV-positive patients without lesion, low-grade squamous intraepithelial lesion (L-SIL), high-grade squamous intraepithelial lesion/squamous cervical carcinoma (H-SIL/SCC). HPV16 type was the most prevalent in H-SIL/SSC 50% (22/44) followed by hr-HPV non-16/18 13.6% (6/44) and in L-SIL 27% (17/63) followed by HPV31-33 14.3% (9/63). In Group 1, HPV16 was detected in 63.3% (7/11) of H-SIL/SCC lesions; in Group 2, HPV16 was detected in 45.5% of H-SIL/SCC lesions (14/32); and in Group 3, HPV16 was detected in one case of H-SIL/SCC. The most prevalent condition was BV in the three groups. In Group 1, 54.2% of HPV16 patients had associated BV. A high prevalence of hr-HPV infection was detected in the 18-24-year age group. HPV16 was the most prevalent type in both the 18-24 and 25-50-year age groups and both HSIL/SSC and L-SIL. BV was the condition most frequently detected, especially in the 18-24-year age group.

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.

CMV is one of the main complications associated with transplantation, whether of solid organs or hematopoietic stem cells, and is related to an increase in post-transplant morbidity and mortality. Due to its significant impact, prevention is recommended, either through prophylaxis or other preventive therapies. The latter require viral monitoring of the patient, as viremia serves as a predictor of of the disease, allowing for an early detection and timely preventive treatment. The gold standard for viral monitoring is the quantitative determination of nucleic acids. Laboratories often face practical challenges regarding the type of sample to be used, its transport and storage conditions, the appropriate methods of nucleic acid extraction and quantification, the frequency of monitoring and establishment of cut-off points to ensure the accuracy and reproducibility of CMV viral load test results. The Argentine Society of Virology has formed a working group specifically dedicated to addressing these difficulties. This document aims to provide recommendations on the aforementioned points based on the available scientific evidence and the expertise of the working group.

Neutropenia has been recognized for many decades as the most important determinant of infection risk in cancer patients. The aim of this study is to describe the clinical and demographic characteristics, type of microbiological isolates, and resistance to antimicrobials of patients with hemato-oncological neoplasms who experienced febrile neutropenia as a complication in a third-level clinic in the city of Cali. A single-center retrospective descriptive study was conducted. Data were retrieved from the medical records of cancer patients who developed post-chemotherapy febrile neutropenia between January 2014 and December 2021. Ninety-six patients were included in the study. An infectious focus was documented in 41% of the cases, with more than one microbiological isolate identified in 2.5%. Gram-negative bacilli predominated, and were isolated in 84.6% of cases. Regarding resistance mechanisms determined phenotypically in E. coli and Klebsiella pneumoniae, ESBL resistance was found in 28.6% and 30% of cases, respectively, and KPC-type carbapenemases in 2.6% of the isolates. Infection-associated mortality was 9.3%. The infectious focus is likely to go undocumented In patients with febrile neutropenia, and infection-associated mortality is low.

Globalization and the introduction of exotic pets have led to the identification of new species that produce tinea in humans. Here, we report the clinical case of a 22-year-old female, who presented with a lesion on her hand that was compatible with dermatophytosis. Molecular biology methods identified the cultured fungus as Trichophyton erinacei.

Salmonella genus includes around 2600 serovars, causing important zoonotic diseases and enteric fever, with significant impact on public health worldwide. Serovar characterization is commonly achieved by phenotypic and genotypic tests, requiring several days to obtain a result. Mass spectrometry (MS) only allows identification of Salmonella isolates at the genus level. Our aim was to evaluate the performance of MS for Salmonella ser. Enteritidis (SE), Salmonella ser. Typhimurium (STM)/4,[5],12:i:- and Salmonella ser. Typhi (ST) specific-serovar biomarker detection. We included 257 isolates from 34 different serovars (62 SE, 69 STM/4,[5],12:i:-, 17 ST) for analysis of spectra obtained by the direct method, using CHCA as matrix. For acquisition, we used Biotyper MicroFlex LT (Bruker Daltonics) and VITEK MS PRIME (BioMérieux) platforms, and performed a manual search for previously described biomarkers. Using Biotyper MicroFlex LT, sensitivity (Se) for the 3016Da and 6036Da SE biomarkers was 85% and 95%, respectively (specificity (Sp)=100%). The Se for the STM/4,[5],12:i:- biomarker (7095Da) was 100% and the Sp=98%. For ST biomarker (5710Da), Se and Sp were 88% and 100%, respectively. For VITEK MS PRIME, Se for the 3018Da SE biomarker was 42% and for the 6036Da was 79% (Sp=100% for both); for the STM/4,[5],12:i:- biomarker (7096Da), Se was 83% and Sp=97%; and for the ST biomarker (5712Da), Se=94% and Sp=100%. The identification of these frequent serovars can be expedited using MALDI-TOF MS technology. The rapid and reliable diagnosis of salmonellosis can have a positive impact on patient outcomes and public health.

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.