Polish journal of microbiology最新文献

The Clostridium perfringens bacteria are used to assess water quality as an indicator parameter. If detected, it can confirm the occurrence of past fecal contamination. Tests determining C. perfringens in water samples are usually performed by membrane filtration where filters are incubated on selective media under anaerobic conditions. Available media include mCP and TSC. The aim of this study was to compare the relative recovery of C. perfringens (including spores) from surface water samples and to determine the performance characteristics of the membrane filtration method using both media. The results showed that, although the procedure using the mCP medium was more sensitive and specific, higher recoveries were obtained in the tests based on the TSC medium.

Algeria is one of the wealthiest countries in terms of hydrothermal sources, with more than two hundred hot springs. However, diverse and little-described microbial communities colonize these habitats, making them an intriguing research subject. This work reports the isolation of bacteria from two hot springs water samples in northeastern Algeria, evaluating their enzymatic activities and effect on plant pathogens. Out of the obtained 72 bacterial isolates and based on the 16S rRNA gene sequence analysis, the strain HGR5 belonging to Bacillus halotolerans had the most interesting activity profile. Interestingly, HGR5 was substantially active against Fusarium graminearum, Phytophthora infestans, and Alternaria alternata. Furthermore, this strain presented a high ability to degrade casein, Tween 80, starch, chitin, cellulose, and xylan. The genome sequence of HGR5 allowed taxonomic validation and screening of specific genetic traits, determining its antagonistic and enzymatic activities. Genome mining revealed that strain HGR5 encloses several secondary metabolite biosynthetic gene clusters (SM-BGCs) involved in metabolite production with antimicrobial properties. Thus, antimicrobial metabolites included bacillaene, fengycin, laterocidine, bacilysin, subtilosin, bacillibactin, surfactin, myxovirescin, dumulmycin, and elansolid A1. HGR5 strain genome was also mined for CAZymes associated with antifungal activity. Finally, the HGR5 strain exhibited the capacity to degrade polycaprolactone (PCL), a model substrate for polyester biodegradation. Overall, these results suggest that this strain may be a promising novel biocontrol agent with interesting plastic-degradation capability, opening the possibilities of its use in various biotechnological applications.

Non-steroidal anti-inflammatory drugs (NSAIDs) commonly used in clinical practice may cause gastrointestinal injuries and influence the gut microbiota. This study investigated the effects of various NSAIDs and some analgesics on the viability of Lactobacillaceae strains (including probiotic strains) in vitro. It was found that diclofenac, ibuprofen, ketoprofen, dexketoprofen, flurbiprofen, and acetylsalicylic acid inhibited the growth of lactobacilli at a concentration of 0.05-3.2 mg/ml. These MICs of NSAIDs are well above therapeutic plasma concentrations achieved in humans, indicating that the tested drugs should not inhibit the growth of lactobacilli in the human digestive tract.

Enteroaggregative Escherichia coli (EAEC) strains have been linked to several outbreaks of severe diarrhea around the world, and this bacterium is now commonly resistant to antibiotics. As part of the pathophysiology of EAEC, the characteristic pattern of adherence looks like stacked bricks on the intestinal epithelium. This phenotype depends on an aggregative adhesion plasmid (pAA), which codes for a regulatory protein named AggR. The AggR protein is a master regulator that transcriptionally actives the main virulence genes in this E. coli pathotype, such as those that encode the aggregative adhesion fimbriae, dispersin and its secretion apparatus, Aar regulatory protein, and type VI secretion system. Several reports have shown that AggR positively affects most EAEC virulence genes, functioning as a classic transcriptional activator in the promoter region of these genes, interacting with the RNA polymerase. This minireview article integrates the information about virulence determinants of EAEC controlled by the AggR regulator.

The Pestalotiopsis sp. strain cr013 is a mycoparasite of Cronartium ribicola, a potential biocontrol fungus for Armand pine (Pinus armandii) blister rust. A previous study showed that the strain cr013 has great potential to produce new compounds. However, there has been no report of the whole-genome sequence of the mycoparasite Pestalotiopsis sp. In this study, the BGISEQ-500 and Oxford Nanopore GridION X5 sequencing platforms were used to sequence the strain cr013 isolates and assemble the reads to obtain the complete genome. We first report the whole-genome information of the mycoparasite Pestalotiopsis sp. strain cr013 (GenBank accession number: JACFXT010000000, BioProject ID: PRJNA647543, BioSample ID: SAMN15589943), and the genomic components and gene functions related to the mycoparasitism process were analyzed. This study provides a theoretical basis for understanding the lifestyle strategy of the mycoparasite Pestalotiopsis sp. and reveals the mechanisms underlying secondary metabolite diversity in the strain cr013.

One of the most relevant and pathogenic groups among the rapidly growing mycobacteria (RGM) is Mycobacterium abscessus complex (MABC) that includes three subspecies: M. abscessus subsp. abscessus, M. abscessus subsp. bolletii, and M. abscessus subsp. massiliense. The aim of this study was the analysis of prevalence of MABC among other non-tuberculous mycobacteria isolated from patients in the Malopolska Region of Poland, between 2018 and 2021, as well as determination of their subspecies and molecular mechanisms of resistance to macrolides and aminoglycosides. The incidence of MABC was 5,4% (12/223). Eight strains were classified as M. abscessus subsp. abscessus, three as M. abscessus subsp. massiliense and one M. abscessus subsp. bolletii. Molecular analysis showed resistance to macrolides for eight strains of M. abscessus subsp. abscessus associated with erm(41)T28 gene mutations. One strain of M. abscessus subsp. abscessus showed resistance to macrolides (two mutations simultaneously: in erm(41)T28 and rrl genes) and aminoglycosides (point mutation in rrs gene). One strain of M. abscessus subs. bolletii was resistant to macrolides (erm(41)T28 mutation), whereas presented no mutations for aminoglycosides. M. abscessus subsp. massiliense reveal no mutations. High clarithromycin resistance of M. abscessus, determines the urgent need for susceptibility-based treatment. Molecular determination of resistance mechanisms to aminoglycosides and macrolides enables fast and accurate targeted treatment implementation.

This study aimed to evaluate the accuracy of detecting drug-resistant Mycobacterium tuberculosis complex (MTBC)-specific DNA in sputum specimens from 48 patients diagnosed with pulmonary tuberculosis. The presence of MTBC DNA in the specimens was validated using the GeneXpert MTB/RIF system and compared with a specific PCR assay targeting the IS6110 and the mtp40 gene sequence fragments. Additionally, the results obtained by multiplex PCR assays to detect the most frequently encountered rifampin, isoniazid, and ethambutol resistance-conferring mutations were matched with those obtained by GeneXpert and phenotypic culture-based drug susceptibility tests. Of the 48 sputum samples, 25 were positive for MTBC using the GeneXpert MTB/RIF test. Nevertheless, the IS6110 and mtp40 single-step PCR revealed the IS6110 in 27 of the 48 sputum samples, while the mtp40 gene fragment was found in only 17 of them. Furthermore, multiplex PCR assays detected drug-resistant conferring mutations in 21 (77.8%) of the 27 samples with confirmed MTBC DNA, 10 of which contained single drug-resistant conferring mutations towards ethambutol and two towards rifampin, and the remaining nine contained double-resistant mutations for ethambutol and rifampin. In contrast, only five sputum specimens (18.5%) contained drug-resistant MTBC isolates, and two contained mono-drug-resistant MTBC species toward ethambutol and rifampin, respectively, and the remaining three were designated as multi-drug resistant toward both drugs using GeneXpert and phenotypic culture-based drug susceptibility tests. Such discrepancies in the results emphasize the need to develop novel molecular tests that associate with phenotypic non-DNA-based assays to improve the detection of drug-resistant isolates in clinical specimens in future studies.

The transmission of human immunodeficiency virus (HIV) through blood poses a slightly increased risk. As a result, patients requiring blood transfusions should be screened for HIV antibodies. This study examined the diagnostic effectiveness of the photostimulated chemiluminescence assay in detecting anti-HIV antibodies and determined the cut-off value for this method. The performance of the fully automated photostimulated chemiluminescence assay system was validated according to CNAS-GL038:2019 (2020) and CNAS-GL037:2019 (2019) guidelines. A retrospective study was conducted at the Department of Medical Laboratory, Nanjing Tongren Hospital, affiliated with Southeast University, from January 2020 to December 2022. A total of 77,386 cases were tested for anti-HIV antibodies using the photostimulated chemiluminescence assay, with 79 cases initially testing positive. The method's performance in detecting anti-HIV antibodies was evaluated using the Receiver Operating Characteristic (ROC) curve and the average Coefficient of Variation (CV) value of 3-year in-house quality control. The precision, detection limit, coincidence rate, and critical value of the performance verification results met the requirements. Using Western blotting (WB) as the reference method, positive cases were initially screened using the light-induced chemiluminescence method to determine the cut-off index (COI) value and draw the ROC curve. The maximum area under the ROC curve using the chemiluminescence method was 0.997, with a cutoff value of < 28.56, sensitivity of 98%, specificity of 100%, Jordan index of 0.98, and an average CV value of 3.55%. In conclusion, the photostimulated chemiluminescence assay has good diagnostic efficacy in detecting anti-HIV antibodies and is suitable for rapid screening before blood transfusion and surgery.

Lung malignancies have a substantial impact on cancer incidence and mortality worldwide. Even though many factors involved in the development of the disease are known, many questions remain unanswered. Previous studies suggest that the intestinal microbiota may have a role in developing malignant diseases. According to some findings, the microbiota has proven to be a key modulator of carcinogenic processes and the immune response against cancer cells, potentially influencing the effectiveness of immunotherapy. In our study, we characterized culturable microorganisms associated with non-small cell lung cancer (NSCLC) that can be recovered from rectal swabs and mouthwash. In addition, we also explored differences in the culturable microbiota with two main types of NSCLC - adenocarcinoma (ADC) and squamous cell carcinoma (SCC). With 141 patients included in the study (86 ADC and 55 SCC cases), a significant difference was observed between the two types in seven bacterial species (Collinsella, Corynebacterium, Klebsiella, Lactobacillus, Neisseria, Rothia, and Streptococcus), including the site of origin. The relationship between microbial dysbiosis and lung cancer is poorly understood; future research could shed light on the links between gut microbiota and lung cancer development.

Acetic acid (AC) is a major by-product from fermentation processes for producing succinic acid (SA) using Actinobacillus succinogenes. Previous experiments have demonstrated that sodium bisulfate (NaHSO₃) can significantly decrease AC production by A. succinogenes GXAS137 during SA fermentation. However, the mechanism of AC reduction is poorly understood. In this study, the transcriptional profiles of the strain were compared through Illumina RNA-seq to identify differentially expressed genes (DEGs). A total of 210 DEGs were identified by expression analysis: 83 and 127 genes up-regulated and down-regulated, respectively, in response to NaHSO₃ treatment. The functional annotation analysis of DEGs showed that the genes were mainly involved in carbohydrates, inorganic ions, amino acid transport, metabolism, and energy production and conversion. The mechanisms of AC reduction might be related to two aspects: (i) the lipoic acid synthesis pathway (LipA, LipB) was significantly down-regulated, which blocked the pathway catalyzed by pyruvate dehydrogenase complex to synthesize acetyl-coenzyme A (acetyl-CoA) from pyruvate; (ii) the expression level of the gene encoding bifunctional acetaldehyde-alcohol dehydrogenase was significantly up-regulated, and this effect facilitated the synthesis of ethanol from acetyl-CoA. However, the reaction of NaHSO₃ with the intermediate metabolite acetaldehyde blocked the production of ethanol and consumed acetyl-CoA, thereby decreasing AC production. Thus, our study provides new insights into the molecular mechanism of AC decreased underlying the treatment of NaHSO₃ and will deepen the understanding of the complex regulatory mechanisms of A. succinogenes.