Revista Argentina de microbiologia最新文献

The Caatinga biome occurs only in Brazil; however, there is no survey on leptospirosis using direct and indirect diagnostic tests in this region with goats maintained in field conditions. We conducted a prospective survey with paired sampling to evaluate the importance of carrier goats in the maintenance of disease. Based on sampling calculation, 60 goats (30 confined and 30 extensively reared) were randomly selected and monitored for three months during the rainy season with paired monthly biological sample collections. The animals underwent urine and vaginal fluid collection for microbiological and molecular diagnosis, and serum samples for serological diagnosis using the microscopic agglutination test (MAT). Overall, 45 (75%) animals were positive in at least one diagnostic method. Anti-Leptospira spp. antibodies were detected in all three sampling moments in 43 (71.7%) animals, antibody titers varied from 25 to 800, and most frequent serogroups were Australis in the 1st and 2nd blood collections (66.7% and 40.7%, respectively) and Cynopteri in the 3rd collection (52.6%). None of the animals tested positive in the microbiological diagnosis or the vaginal fluid PCR; however, five (16.7%) animals were positive in the urine PCR only in the confined group in the first collection. Two DNA urine samples were sequenced, demonstrating 99% similarity with Leptospira interrogans. Different diagnostic techniques for leptospirosis in goats raised under Caatinga biome field conditions are suggested, as well as further studies over a longer period with monthly collections to better understand the prevalence of Leptospira spp. and its variation over time.

Cicer arietinum L. is a vital source of nutrients that suffers substantial annual losses due to Ascochyta blight, caused by the plant pathogen Ascochyta rabiei. This study aimed to investigate the antifungal potential of Ocimum tenuiflorum L. and O. basilicum L. shoots (leaves and stems) against A. rabiei (Pass) Lab. In vitro bioassays were conducted using methanolic extracts from leaves and stems at six different concentrations: 1%, 1.5%, 2%, 2.5%, 3%, and 3.5%. A total of eight compounds were identified through gas chromatography-mass spectrometry (GC-MS) analysis. The highest inhibition of A. rabiei growth was achieved with a 3.5% methanolic leaf extract of O. basilicum. Methanolic extracts from O. tenuiflorum shoots also reduced fungal growth by 6.18-73%. Additionally, the n-hexane fraction derived from O. basilicum inhibited fungal growth by 71-76% and was subsequently analyzed using GC-MS. This analysis identified eight compounds: (1) cyclopentane, methyl-, (2) cyclohexane, (3) 2,2-dimethylbutane, (4) 2,3-dimethylbutane, pentane, (5) 2,3-dimethyl-, (6) 2-bromoacetonitrile, (7) alpha-cadinol, and (8) phenylpropanolamine. The antioxidant activity of O. tenuiflorum and O. basilicum shoots was also assessed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The highest antioxidant activity, 98.58%, was recorded at a 3.5% methanolic stem extract concentration of O. tenuiflorum. The antioxidant activity potential was highest for O. tenuiflorum at 0.729mg/mL, followed by O. basilicum at 0.411mg/mL.

Water kefir is a fermented beverage that has experienced a growing popular interest in its production, commercialization and consumption. However, it was not contemplated as such in the Argentine Food Code (CAA, Spanish acronym). The aim of this work was to determine some microbiological and physicochemical characteristics of water kefir samples produced by Argentine entrepreneurs, to have the necessary information for the National Food Commission (CONAL, Spanish acronym) to generate an article incorporating water kefir in the CAA. For this purpose, 31 water kefir producers from different cities of the country were invited to send samples of their products for microbiological and physicochemical analysis to the National Reference Laboratory of the National Food Institute (INAL, Spanish acronym) (Buenos Aires, Argentina). In the period December 2021-February 2022, a total of 13 samples were received, together with the corresponding information on their production process. The samples analyzed showed a pH between 2.9 and 3.7, a titratable acidity between 6 and 16.6 (ml of NaOH 1N/100ml of sample), an alcohol content between 0.58 and 2.55 (%v/v), a lactic acid bacteria count of 1×10⁷CFU/ml and a yeast count of 1×10⁶CFU/ml, with enterobacteria counts lower than 10CFU/ml). The results provided local data that culminated in the publication, on August 12, 2024, of the joint resolution 7/2024 of the Secretariat of Quality in Health and Secretariat of Bioeconomy by which article 1084 tris was incorporated to the CAA in the chapter XIII of fermented beverages, referring to water kefir.

The main current diagnostic challenge in Clostridioides difficile infection (CDI) is to detect patients with the poorest prognoses. We have studied the association between the presence of toxin in the feces, the amplification of the toxin B gene at low cycles in PCR (Ct), and the detection of the binary toxin or ribotype with severity, recurrence, and poor prognosis. Toxigenic C. difficile has been investigated in adult diarrheal feces, regardless of the clinical request. Glutamate dehydrogenase (GDH), toxin A (TcdA) and toxin B (TcdB) have been assessed by immunoassay and the gene encoding toxin B (tcdB) and the binary toxin (cdtA) by PCR. The toxigenic strains recovered by toxigenic culture were typed by PCR-Ribotyping and subtyped by MLVA (multilocus-variable number tandem DNA repeat analysis). Eighty-two (82) cases of CDI were detected from 677 samples (12.1%). Patients with Ct ≤ 27.5 often presented criteria for severity, recurrence, and poor prognosis (59.3% versus 40.7%, P=.15; 80% versus 20%, P=.10; and 60.3% versus 39.7%, P=.055, respectively). The mean Ct was lower when recurrence was observed (25.48; SD=2.41; P=.058). By logistic regression, the variable most likely to indicate a poor prognosis was Ct ≤ 27.5 (OR=2.663; 95% CI=.983-7.636; P=.059). In summary, the cycle threshold of the PCR for toxin B is a possible marker of severity, recurrence, and poor prognosis in CDI. The diversity of ribotypes observed is remarkable, with no clonal relationship between isolates of the same ribotype.

The confirmation of two cases of hantavirus pulmonary syndrome (HPS) in the city of San Miguel de Tucuman, province of Tucuman, is described in the present study. In 2021, the diagnosis of two patients with HPS with no history of travel outside the province was confirmed. The infection was determined by serology in both cases. Case 1 had an unfavorable outcome, was confirmed by the detection of specific IgM antibodies for orthohantavirus and the identification in a serum sample from three days of evolution of a viral genotype, which was previously unreported to be in circulation in Argentina. In Case 2, specific IgM and IgG type antibodies were detected in two serum samples, with no amplification of the viral genome. Due to the recreational habits of the patients, it is possible to infer exposure to infected rodent fluids during outdoor activities in their areas of residence. In conclusion, the circulation of a new viral genotype of orthohantavirus in Argentina is confirmed.

We conducted a prolective cohort study with the aim of estimating the incidence of healthcare-associated infections and identifying associated factors in an intensive care unit in Mexico. Diagnosis of central venous catheter-associated bacteremia, ventilator-associated pneumonia and urinary catheter-associated urinary tract infection was established according to the Centers for Disease Control and Prevention definitions; risk factors were analyzed by logistic regression. Four hundred twenty-six patients who had 486 admissions were studied, 55.9% were male and the median age was 4 years. The healthcare-associated infections incidence rate was 14.8 events/1000 patient-days. The prevalent microorganisms were gram negative bacilli. The factors associated with healthcare-associated infections were chronic conditions (p=0,01), the number of central venous catheters inserted and the days duration of central venous catheter, mechanical ventilation and the urinary catheter (the 4 variables with p≤0.001).

The aim of this study was to identify the clinical and demographic characteristics of patients with a confirmed diagnosis of spondylodiscitis through microbiological cultures. A descriptive, observational, and retrospective study was conducted. Patients were included based on clinical and radiological evidence of vertebral infection, unspecified discitis, and/or positive microbiological cultures consistent with spondylodiscitis. For the comparison between men and women, the Student's t-test and odds ratio were employed. The Chi-square test was used to examine correlations between affected spinal levels, isolated microorganisms, and associated comorbidities. A total of 86 cases of discitis were identified, 65% of which involved male patients. The mean age was 59.0±11.5 years (range: 38-83), and the average body mass index (BMI) was 28±4.05kg/m². Primary discitis predominated in 68% of cases, mainly at the thoracic level. Seventeen patients presented with spondylodiscitis not associated with chronic degenerative diseases. The most frequently isolated microorganisms were Staphylococcus aureus (28 cases) and Escherichia coli (21 cases). In 16 cases, intracellular pathogens such as Mycobacterium tuberculosis and Brucella spp. were identified, leading to an average hospital stay of 30 days. Spondylodiscitis is a serious complication, and this study highlights differences from previously published data, particularly in terms of the microorganisms involved and the demographic profile of the population.

The emergence and spread of multidrug-resistant Escherichia coli carrying mcr-1 is recognized as a threat to public health. The aim of this study was to determine the prevalence of the mcr-1 gene in colistin-resistant E. coli isolates from commercial pig farms in Chaco, Argentina from 2020 to 2021. A total of 140 rectal swab samples were collected from pigs in six different pig production farms. Antimicrobial susceptibility was determined by broth microdilution. mcr-1 to mcr-5 genes were identified by multiplex PCR and clonality was assessed by ERIC and REP-PCR. The prevalence of mcr-1 was 16.4% and mcr-2, mcr-3, mcr-4 and mcr-5 genes were not detected. Colistin MIC values showed a bimodal distribution with a MIC50, MIC90 and a range of 4, 8 and 4-8μg/ml, respectively. The resistance profile to other antimicrobials was: ampicillin, 87% (20); ampicillin-sulbactam, 47.8% (11); amoxicillin-clavulanic, 13% (3); chloramphenicol, 82.6% (19); ciprofloxacin, 60.9% (14); minocycline, 26.1% (5) and trimethoprim/sulfamethoxazole, 43.5% (10). Eighty-seven percent (87%) of the strains were categorized as MDR and 12 phenotypic resistance patterns with different clonality profiles were observed. A high prevalence of mcr-1 is demonstrated in colistin-free pig farms from Chaco, Argentina. The mcr-1 positive E. coli isolates showed an alarming level of multidrug resistance and high clonal diversity. It is necessary to continuously monitor the presence of the mcr-1 gene not only in pig production, but also in humans and the environment.

Protothecosis is an infectious disease caused by microalgae of the genus Prototheca. Prototheca can be found in soil and water and transiently colonize animals. Cutaneous protothecosis can involve not only the skin but also the underlying subcutaneous tissue and lymph nodes. This can lead to clinical signs and a microscopic tissue image that closely resembles a fungal infection. Treatment typically involves antifungal medications. We report the first case of fatal disseminated protothecosis caused by Prototheca wickerhamii in the city of Rosario, Argentina in a 5-year-old female poodle dog. The dog exhibited ocular signs of uveitis and lymphadenitis. To reach a clinical and etiological diagnosis, imaging studies, routine laboratory tests and serological tests were performed. A mycological analysis was conducted on the material obtained by puncturing three lymph nodes. Additionally, morphological, metabolic, and molecular analyses were performed. Antifungal susceptibility testing was also conducted using broth microdilution and diffusion methods. Phenotypic, metabolic, and sequencing techniques identified the isolated organism as P. wickerhamii. This isolate displayed susceptibility to amphotericin, variable susceptibility to itraconazole and voriconazole, and resistance to fluconazole and caspofungin. The frequent presence of pets in our homes highlights the need for a more comprehensive diagnostic approach. This is important because, from a public health perspective, dogs could serve as indicators of algal presence in the environments they frequently share with humans.