<abstract><title style='display:none'>Abstract</title>Urinary tract infections (UTIs) belong to the most common community-acquired and nosocomial infections. A main etiological factor of UTIs is uropathogenic <italic>Escherichia coli</italic> (UPEC). This review describes the current state of knowledge on the resistance of UPEC to antibiotics recommended for the treatment of UTIs based on the available literature data. Nitrofurantoin and fosfomycin are recommended as first-line therapy in the treatment of uncomplicated cystitis, and the resistance to these antimicrobial agents remains low between UPEC. Recently, in many countries, the increasing resistance is observed to trimethoprim-sulfamethoxazole, which is widely used as the first-line antimicrobial in the treatment of uncomplicated UTIs. In European countries, the resistance of UPEC to this antimicrobial agent ranges from 14.6% to 60%. The widespread use of fluoroquinolones (FQs), especially ciprofloxacin, in the outpatients is the cause of a continuous increase in resistance to these drugs. The resistance of UPEC to FQs is significantly higher in developing countries (55.5–85.5%) than in developed countries (5.1–32.0%). Amoxicillin-clavulanic acid is recommended as first line-therapy for pyelonephritis or complicated UTI. Resistance rates of UPEC to amoxicillin-clavulanic acid are regionally variable. In European countries the level of resistance to this antimicrobial ranges from 5.3% (Germany) to 37.6% (France). Increasing rates of UPEC resistance to antimicrobials indicate that careful monitoring of their use for UTI treatment is necessary.</abstract>

Antibiotic Resistance Among Uropathogenic <italic>Escherichia coli</italic>

<abstract><title style='display:none'>Abstract</title><italic>Brucellae</italic> are Gram-negative, small rods infecting mammals and capable of causing disease called brucellosis. The infection results in abortion and sterility in domestic animals (sheeps, pigs, rams etc). Especially dangerous for humans are: <italic>Brucella melitensis, Brucella suis, Brucella abortus</italic>, and <italic>Brucella canis</italic> that trigger unspecific symptoms (flu-like manifestation). <italic>Brucella</italic> rods are introduced via host cells, by inhalation, skin abrasions, ingestion or mucosal membranes. The most important feature of <italic>Brucella</italic> is the ability to survive and multiply within both phagocytic and non-phagocytic cells. <italic>Brucella</italic> does not produce classical virulence factors: exotoxin, cytolisins, exoenzymes, plasmids, fimbria, and drug resistant forms. Major virulence factors are: lipopolysaccharide (LPS), T4SS secretion system and BvrR/BvrS system, which allow interaction with host cell surface, formation of an early, late BCV (<italic>Brucella</italic> Containing Vacuole) and interaction with endoplasmic reticulum (ER) when the bacteria multiply. The treatment of brucellosis is based on two-drug therapy, the most common combinations of antibiotics are: doxycycline with rifampicin or fluoroquinolones with rifampicin. Currently, also other methods are used to disrupt <italic>Brucella</italic> intracellular replication (tauroursodeoxycholic acid or ginseng saponin fraction A).</abstract>

<italic>Brucella</italic> – Virulence Factors, Pathogenesis and Treatment

<abstract><title style='display:none'>Abstract</title>Research on the susceptibility of the spores of anaerobic bacteria such as <italic>Clostridium sporogenes</italic> or <italic>Clostridioides difficile</italic> is vital for assessing the sporicidal activity of disinfectants. The diverse susceptibility of anaerobic bacteria spores may lead to different disinfection parameters being determined by laboratories that prepare spore suspensions to test sporicidal effectiveness. The tests were performed using the suspension method according to PN-EN 13704:2018-09. In order to assess the susceptibility of the <italic>C. sporogenes</italic> spores, the criterion established for the <italic>C. difficile</italic> ribotype 027 spores was used in accordance with PN‑EN 17126:2019-01. The susceptibility of the <italic>C. sporogenes</italic> spores to glutardialdehyde corresponded to the susceptibility ranges established for the <italic>C. difficile</italic> ribotype 027 spores. The <italic>C. sporogenes</italic> spore suspension was susceptible to low concentrations of peracetic acid (0.01%). A disinfectant containing peracetic acid as the active substance showed high sporicidal activity at a low concentration (1%), a short contact time (15 minutes), and a high organic load (3.0 g/l bovine albumin + 3.0 ml/l sheep erythrocytes), as compared to a disinfectant with glutardialdehyde, which was sporicidal at a higher concentration (2.5%), at a longer contact time
(60 minutes) and lower organic conditions (3.0 g/l bovine albumin). There is a need to define the minimum susceptibility criteria for the <italic>C. sporogenes</italic> spores to the reference substances most often found in disinfectants with sporicidal activity. Excessive susceptibility of the <italic>C. sporogenes</italic> spores to reference substances may result in low-performance parameters of disinfection products with sporicidal activity and lead to ineffective disinfection in practice.<fig id="j_pjm-2022-031_fig_001" position="float" fig-type="figure">
<graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_pjm-2022-031_fig_001.jpg"/>
</fig></abstract>

Susceptibility of <italic>Clostridium sporogenes</italic> Spores to Selected Reference Substances and Disinfectants

<abstract>
<title style='display:none'>Abstract</title>
This study aims to evaluate associations between the immunochromatographic rapid test technique and <italic>Trichomonas vaginalis</italic> (TV) infection in patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) in Taiwan. All patients received post-prostate massage urine (VB3) Trichomonas rapid tests. The demographic characteristics and urogenital symptoms of CP/CPPS were recorded. Routine urinalysis of VB3 was also performed, and laboratory examination results of semen were recorded if available. A total of 29 patients with TV infection and 109 without TV infection were enrolled, which reflected that the prevalence in patients with TV infection was approximately 21%. Patients with TV infection displayed a significantly higher frequency of suprapubic/lower abdominal pain (<italic>p</italic> = 0.034), semen leukocyte &gt; 5/high-power field (HPF) (<italic>p</italic> = 0.020), and an inflammatory type (category IIIA) (<italic>p</italic> = 0.005) than patients without TV infection. A higher prevalence of TV infection was found in patients with category IIIA (47.37%). No significant difference was found in the symptom duration and other clinical symptoms. In conclusion, the high prevalence of TV infection was revealed in CP/CPPS patients using the VB3 rapid Trichomonas test, especially in CP/CPPS patients with category IIIA. Thus, rapid TV testing might be vital for CP/CPPS patients in the hospital.</abstract>

Detection of <italic>Trichomonas vaginalis</italic> Infection in Chronic Prostatitis/Chronic Pelvic Pain Syndrome Patients by Rapid Immunochromatographic Test

<abstract><title style='display:none'>Abstract</title>Several biotypes of the Gram-negative bacterium <italic>Serratia marcescens</italic> produce the tri-pyrole pigment and secondary metabolite prodigiosin. The biological activities of this pigment have therapeutic potential. For over half a century it has been known that biosynthesis of prodi giosin is inhibited when bacteria are grown at elevated temperatures, yet the fundamental mechanism underlying this thermoregulation has not been characterized. In this study, chromosomal and plasmid-borne <italic>luxCDABE</italic> transcriptional reporters revealed reduced transcription of the prodigiosin biosynthetic operon at 37°C compared to 30°C indicating transcriptional control of pigment production. Moreover, induced expression of the prodigiosin biosynthetic operon at 37°C was able to produce pigmented colonies and cultures demonstrating that physiological conditions at 37°C allow prodigiosin production and indicating that post-transcriptional control is not a major contributor to the thermoregulation of prodigiosin pigmentation. Genetic experiments support the model that the HexS transcription factor is a key contributor to thermoregulation of pigmentation, whereas CRP plays a minor role, and a clear role for EepR and PigP was not observed. Together, these data indicate that thermoregulation of prodigiosin production at elevated temperatures is controlled largely, if not exclusively, at the transcriptional level.</abstract>

Thermoregulation of Prodigiosin Biosynthesis by <italic>Serratia marcescens</italic> is Controlled at the Transcriptional Level and Requires HexS

<abstract>
<title style='display:none'>Abstract</title>
Bacteria play a fundamental role in the cycling of nutrients in aquatic environments. A precise distinction between active and inactive bacteria is crucial for the description of this process. We have evaluated the usefulness of Coomassie Blue G250 for fluorescent staining of protein containing potentially highly active bacteria. We found that the G250 solution has excitation and emission properties appropriate for direct epifluorescence microscopy observations. It enables fast and effective fluorescent visualization of living, protein-rich bacteria, both in freshwater environment and culture. Our results revealed that the number of G250-stained bacteria from eutrophic lake was positively correlated with other standard bacterial activity markers, like number of bacteria containing 16S rRNA, bacterial secondary production or maximal potential leucine-aminopeptidase activity. In case of the <italic>E. coli</italic> culture, the percentage of bacteria visualized with G250 was similar to that of bacteria which accumulated tetracycline. Compared to other common methods utilizing fluorogenic substances for bacteria staining, the approach we evaluated is inexpensive and less hazardous (for example mutagenic) to the environment and researchers. It can be regarded as an additional or alternative method for protein rich, active bacteria staining.
</abstract>

Coomassie Blue G250 for Visualization of Active Bacteria from Lake Environment and Culture

<abstract>
<title style='display:none'>Abstract</title>
Shiga toxin-producing <italic>Escherichia coli</italic> (STEC) are zoonotic pathogens causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in children and the elderly. Stool samples were collected from 180 children hospitalized in five pediatric centers in Poland in 2018–2022. Direct <italic>stx1</italic>/<italic>stx2</italic> gene detection by PCR in feces and <italic>E. coli</italic> isolates was performed. Antibiotic susceptibility was tested according to EUCAST v.12. Randomly selected isolates were serotyped with O157 antiserum and genotyped by pulsed-field gel electrophoresis (PFGE). A total of 44 <italic>E. coli</italic> isolates were confirmed as STEC by PCR. Among them, 84.4% were positive for <italic>stx2</italic>, and equally 6,8% for only <italic>stx1</italic> and both <italic>stx1</italic> and <italic>stx2</italic> genes. The <italic>stx1</italic> gene was also found in one <italic>Citrobacter freundii</italic> isolate. <italic>E. coli</italic> serotype O157 was present in 97.6% of the isolates. STEC infections most often occurred between June-October with a peak in July and August (51%). The highest, 77.8% of STEC isolates were found in the 1–5 years old group. No extended-spectrum β-lactamases (ESBL) were found. Resistance only to amoxicillin/clavulanic acid (24.4%), piperacillin/tazobactam (3%), cefotaxime (6%), gentamicin (6%), ciprofloxacin (3%), azithromycin (3%), trimethoprim/sulfamethoxazole (24,2%) was detected. PFGE analysis showed 18 PFGE types with no clonal distribution. Eight isolates with A, B, and C PFGE types showed genetic relatedness in the type with no detection of transmission way of distribution. STEC strains pose a serious threat to human health, therefore demographic and epidemiological characteristics are crucial for their surveillance.
</abstract>

Epidemiological Characteristics of Shiga Toxin-Producing <italic>Escherichia coli</italic> Responsible for Infections in the Polish Pediatric Population

<abstract>
<title style='display:none'>Abstract</title>
This study aimed to investigate azole resistance mechanisms in <italic>Aspergillus flavus,</italic> which involve <italic>cyp</italic>51A and <italic>cyp</italic>51B genes. Real-time Reverse Transcriptase qPCR method was applied to determine the overexpression of <italic>cyp</italic>51A and <italic>cyp</italic>51B genes for 34 <italic>A. flavus</italic> isolates. PCR sequencing of these two genes was used to detect the presence of gene mutations. Susceptibility test found sensitivity to voriconazole (VOR) in all strains. 14.7% and 8.8% of isolates were resistant to itraconazole (IT) and posaconazole (POS), respectively, with a cross-resistance in 5.8%. For the double resistant isolates (IT/POS), the expression of <italic>cyp</italic>51A was up to 17-fold higher. PCR sequencing showed the presence of 2 mutations in <italic>cyp</italic>51A: a synonymous point mutation (P61P) in eight isolates, which did not affect the structure of CYP51A protein, and another non synonymous mutation (G206L) for only the TN-33 strain (cross IT/POS resistance) causing an amino acid change in the protein sequence. However, we noted in <italic>cyp</italic>51B the presence of the only non-synonymous mutation (L177G) causing a change in amino acids in the protein sequence for the TN-31 strain, which exhibits IT/POS cross-resistance. A short single intron of 67 bp was identified in the <italic>cyp</italic>51A gene, whereas three short introns of 54, 53, and 160 bp were identified in the <italic>cyp</italic>51B gene. According to the models provided by PatchDock software, the presence of non-synonymous mutations did not affect the interaction of CYP51A and CYP51B proteins with antifungals. In our study, the overexpression of the <italic>cyp</italic>51A and <italic>cyp</italic>51B genes is the primary mechanism responsible for resistance in <italic>A. flavus</italic> collection. Nevertheless, other resistance mechanisms can be involved.
</abstract>

Investigation of Azole Resistance Involving <italic>cyp</italic>51A and <italic>cyp</italic>51B Genes in Clinical <italic>Aspergillus flavus</italic> Isolates

<abstract>
<title style='display:none'>Abstract</title>
Sub-high temperature Daqu, a traditional solid fermenting agent used in Chinese strong-aroma Baijiu production, is abundant in diverse microorganisms, including bacteria, yeasts, molds, and actinomycetes. Among these, yeasts are pivotal for ethanol production and flavor formation. However, counting yeasts in Daqu is challenging due to interference from molds and bacteria. Antibiotics are employed to inhibit bacterial growth, but there is no practical way to suppress molds without affecting the growth of yeasts. In this study, short-chain carboxylates (C1-C6) were added to the culture medium at various pH conditions to investigate their effects on the growth of molds and yeasts. The results demonstrated distinct inhibitory effects of the short-chain carboxylates, depending on both pH and concentration. Several tested short-chain carboxylates effectively suppressed mold growth on agar plates while leaving yeast growth unaffected. This suggests a simple and feasible method for enhancing the efficiency of yeast isolation and counting in Daqu. Such an approach is valuable for studying yeasts in diverse and complex habitats.
</abstract>

Short-Chain Carboxylates Facilitate the Counting of Yeasts in Sub-High Temperature Daqu

<abstract>
<title style='display:none'>Abstract</title>
Proteases derived from <italic>Streptomyces</italic> demonstrate numerous commendable properties, rendering it extensively applicable in biotechnology and various industrial sectors. This study focused on the purification and characterization of the thermostable protease obtained from <italic>Streptomyces</italic> sp. CNXK100. The purified protease exhibited an estimated molecular weight of 27 kDa, with optimal activity at 75°C and pH 8.0. Notably, the enzyme remained active even without any metal ions and fully active in the presence of Na+, K+, Mg2+, and Cu2+metal ions. The kinetic parameters were determined with a <italic>KM</italic> value of 3.13 mg/ml and a <italic>Vmax</italic> value of 3.28 × 106 U/mg. Furthermore, the protease has demonstrated notable stability when subjected to a treatment temperature of up to 65°C for 60 minutes, and across a broad pH range extending from 5.0 to 10.0. This protease also demonstrated resilience against a spectrum of harsh conditions, including exposure to organic solvents, surfactants, bleaching agents, and proteolytic enzymes. Additionally, the enzyme maintained its activity following treatment with commercial detergents, accomplishing complete thrombus lysis at a concentration of 2.50 mg/ml within 4 hours. Remarkably, the protease exhibited stability in terms of activity and protein concentration for 70 days at 4°C. These findings underscore the potential industrial applications of the thermostable protease from <italic>Streptomyces</italic> sp. CNXK100.
<fig id="j_pjm-2024-014_fig_010" position="float" fig-type="figure">
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</fig>
</abstract>

Purification and Characterization of a Small Thermostable Protease from <italic>Streptomyces</italic> sp. CNXK100

<abstract>
<title style='display:none'>Abstract</title>
Electricigens decompose organic matter and convert stored chemical energy into electrical energy through extracellular electron transfer. They are significant biocatalysts for microbial fuel cells with practical applications in green energy generation, effluent treatment, and bioremediation. A facultative anaerobic electrogenic strain SQ-1 is isolated from sludge in a biotechnology factory. The strain SQ-1 is a close relative of <italic>Klebsiella variicola</italic>. Multilayered biofilms form on the surface of a carbon electrode after the isolated bacteria are inoculated into a microbial fuel cell device. This strain produces high current densities of 625 μA cm–2 by using acetate as the carbon source in a three-electrode configuration. The electricity generation performance is also analyzed in a dual-chamber microbial fuel cell. It reaches a maximum power density of 560 mW m–2 when the corresponding output voltage is 0.59 V. The facultative strain SQ-1 utilizes hydrous ferric oxide as an electron acceptor to perform extracellular electricigenic respiration in anaerobic conditions. Since facultative strains possess better properties than anaerobic strains, <italic>Klebsiella</italic> sp. SQ-1 may be a promising exoelectrogenic strain for applications in microbial electrochemistry.
<fig id="j_pjm-2024-013_fig_006" position="float" fig-type="figure">
<graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_pjm-2024-013_fig_006.jpg"/>
</fig>
</abstract>

Isolation and Electrochemical Analysis of a Facultative Anaerobic Electrogenic Strain <italic>Klebsiella</italic> sp. SQ-1

<abstract>
<title style='display:none'>Abstract</title>
<italic>Salmonella enterica</italic> is a common pathogen in humans and animals that causes food poisoning and infection, threatening public health safety. We aimed to investigate the genome structure, drug resistance, virulence characteristics, and genetic relationship of a <italic>Salmonella</italic> strain isolated from patients with food poisoning. The pathogen strain 21A was collected from the feces of patients with food poisoning, and its minimum inhibitory concentration against commonly used antibiotics was determined using the strip test and Kirby-Bauer disk methods. Subsequently, WGS analysis was used to reveal the genome structural characteristics and the carrying status of resistance genes and virulence genes of strain 21A. In addition, an MLST-based minimum spanning tree and an SNP-based systematic spanning tree were constructed to investigate its genetic evolutionary characteristics. The strain 21A was identified by mass spectrometry as <italic>S. enterica</italic>, which was found to show resistance to ampicillin, piperacillin, sulbactam, levofloxacin, and ciprofloxacin. The WGS and bioinformatics analyses revealed this strain as <italic>Salmonella</italic> Enteritidis belonging to ST11, which is common in China, containing various resistance genes and significant virulence characteristics. Strain 21A was closely related to the SJTUF strains, a series strains from animal, food and clinical sources, as well as from Shanghai, China, which were located in the same evolutionary clade. According to the genetic makeup of strain 21A, the change G &gt; A was found to be the most common variation. We have comprehensively analyzed the genomic characteristics, drug resistance phenotype, virulence phenotype, and genetic evolution relationship of <italic>S</italic>. Enteritidis strain 21A, which will contribute towards an in-depth understanding of the pathogenic mechanism of <italic>S</italic>. Enteritidis and the effective prevention and control of foodborne diseases.
</abstract>

Isolation, Identification, Antimicrobial Resistance, Genotyping, and Whole-Genome Sequencing Analysis of <italic>Salmonella</italic> Enteritidis Isolated from a Food-Poisoning Incident

<abstract><title style='display:none'>Abstract</title>The growing resistance of microorganisms towards antibiotics has become a serious global problem. Therapeutics with novel chemical scaffolds and/or mechanisms of action are urgently needed to combat infections caused by multidrug resistant pathogens, including bacteria, fungi and viruses. Development of novel antimicrobial agents is still highly dependent on the discovery of new natural products. At present, most antimicrobial drugs used in medicine are of natural origin. Among the natural producers of bioactive substances, Actinobacteria continue to be an important source of novel secondary metabolites for drug application. In this review, the authors report on the bioactive antimicrobial secondary metabolites of Actinobacteria that were described between 2011 and April 2018. Special attention is paid to the chemical scaffolds, biological activities and origin of these novel antibacterial, antifungal and antiviral compounds. Arenimycin C, chromopeptide lactone RSP 01, kocurin, macrolactins A1 and B1, chaxamycin D as well as anthracimycin are regarded as the most effective compounds with antibacterial activity. In turn, the highest potency among selected antifungal compounds is exhibited by enduspeptide B, neomaclafungins A-I and kribelloside D, while ahmpatinin iBu, antimycin A1a, and pentapeptide 4862F are recognized as the strongest antiviral agents.</abstract>

Secondary Metabolites of Actinomycetes and their Antibacterial, Antifungal and Antiviral Properties

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 eISSN: 2544-4646Print ISSN: 1733-1331   The Polish Journal of Microbiology (PJM), founded in 1952 as Acta Microbiologica, is a...

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 eISSN: 2544-4646Print ISSN: 1733-1331   The Polish Journal of Microbiology (PJM), founded...

Polish Journal of Microbiology

Epidemiological Characteristics of Shiga Toxin-Producing Escherichia coli Responsible for Infections in the Polish Pediatric Population

Investigation of Azole Resistance Involving cyp51A and cyp51B Genes in Clinical Aspergillus flavus Isolates

Short-Chain Carboxylates Facilitate the Counting of Yeasts in Sub-High Temperature Daqu

Purification and Characterization of a Small Thermostable Protease from Streptomyces sp. CNXK100

Isolation and Electrochemical Analysis of a Facultative Anaerobic Electrogenic Strain Klebsiella sp. SQ-1

Isolation, Identification, Antimicrobial Resistance, Genotyping, and Whole-Genome Sequencing Analysis of Salmonella Enteritidis Isolated from a Food-Poisoning Incident