Phenotypic profile of priority multiresistant Аcinetobacter baumannii sequence types (ST 1167, ST 944, ST 208)

Introduction. About 1,000,000 cases of infections caused by Acinetobacter spp. per year are registered globally, making up 1.8% of all the cases of hospital-acquired infections. In compliance with long-term studies carried out in in this country and abroad, Acinetobacter baumannii is a clinically important representative of the Acinetobacter genus. Intraspecific typing of microorganisms is an integral part of a clinical microbiologist's contribution to scoring the outbreaks of purulent-septic infections within the sphere of HAI surveillance. Most of the practicing microbiological laboratories cannot use genotypic typing methods because of their high costs.Objective. Developing a test panel for intraspecific identification of A. baumannii sequence types (ST 1167, ST 944, ST 208) based on their phenotypic properties.Materials and methods. Intraspecific membership of 74 A. baumannii strains obtained from four multipurpose health settings of a large industrial centre was studied using a genetic method (multilocus sequence typing) and a suite of phenotypic methods (biochemical tests, biofilmogenous capacity, growth inhibition zones to antibacterial drugs, sensitivity to aniline dyes, disinfectants and Acinetobacter bacteriophage) was studied.Results. Phenotypic features of three predominant A. baumannii sequence types (ST 1167, 944, 208) were determined.Discussion. An efficacious economy set of differentiating tests allowing identification of intraspecific features of A. baumannii multiresistant strains was сreated.Conclusion. The test panel will enable the laboratories that cannot use sequencing methods to conduct intraspecific differentiation of common A. baumannii sequence types as part of microbiological monitoring.

Evaluation of Antibiotic Resistance of Salmonella Serotypes and Whole-Genome Sequencing of Multiresistant Strains Isolated from Food Products in Russia

Food products may be a source of Salmonella, one of the main causal agents of food poisoning, especially after the emergence of strains resistant to antimicrobial preparations. The present work dealt with investigation of the occurrence of resistance to antimicrobial preparations among S. enterica strains isolated from food. The isolates belonged to 11 serovars, among which Infantis (28%), Enteritidis (19%), and Typhimurium (13.4%) predominated. The isolates were most commonly resistant to trimethoprim/sulfamethoxazole (n = 19, 59.38%), cefazolin (n = 15, 46.86%), tetracycline (n = 13, 40.63%), and amikacin (n = 9, 28.13%). Most of the strains (68.75%) exhibited multiple resistance to commonly used antibiotics. High-throughput sequencing was used to analyse three multidrug-resistant strains (resistant to six or more antibiotics). Two of them (SZL 30 and SZL 31) belonged to S. Infantis, while one strain belonged to S. Typhimurium (SZL 38). Analysis of the genomes of the sequenced strains revealed the genes responsible for antibiotic resistance. In the genomes of strains SZL 30 and SZL 31 the genes of antibiotic resistance were shown to be localized mostly in integrons within plasmids, while most of the antibiotic resistance genes of strain SZL 38 were localized in a chromosomal island (17,949 nt). Genomes of the Salmonella strains SZL 30, SZL 31, and SZL 38 were shown to contain full-size pathogenicity islands: SPI-1, SPI-2, SPI-4, SPI-5, SPI-9, SPI-11, SPI-13, SPI-14, and CS54. Moreover, the genome of strain SZL 38 was also found to contain the full-size pathogenicity islands SPI-3, SPI-6, SPI-12, and SPI-16. The emergence of multidrug-resistant strains of various Salmonella serovars indicates that further research on the transmission pathways for these genetic determinants and monitoring of the distribution of these microorganisms are necessary.

Significance of gram-resistant flora in etiology of nosocomial infections in determining rational antibiotic therapy

In recent years, the problem of resistance of gram-negative microorganisms to carbapenems, as well as the emergence of multiresistant strains is gaining urgency. This problem is of particular importance in neonatal practice due to the age limitations of the use of many antibiotics and the lack of specific recommendations. Local bacteriological monitoring data should be taken into account when selecting a starting antibiotic, and for this purpose, methods of rapid identification of the pathogen and its resistance mechanisms should be introduced. Pediatricians need controlled trials of new antibiotics to successfully treat MDR-Gram-infections.

Antistaphylococcal Activity of the FtsZ Inhibitor C109

Staphylococcus aureus infections represent a great concern due to their versatility and involvement in different types of diseases. The shortage of available clinical options, especially to treat multiresistant strains, makes the discovery of new effective compounds essential. Here we describe the activity of the previously described cell division inhibitor C109 against methicillin-sensitive and -resistant S. aureus strains. Antibiofilm activity was assessed using microtiter plates, confocal microscopy, and in an in vitro biofilm wound model. The ability of C109 to block FtsZ GTPase activity and polymerization was tested in vitro. Altogether, the results show that the FtsZ inhibitor C109 has activity against a wide range of S. aureus strains and support its use as an antistaphylococcal compound.

Unveiling Biological Activities of Marine Fungi: The Effect of Sea Salt

There is an urgent need for new substances to overcome current challenges in the health sciences. Marine fungi are known producers of numerous compounds, but the manipulation of growth conditions for optimal compound production can be laborious and time-consuming. In Portugal, despite its very long coastline, there are only a few studies on marine fungi. From a collection of Portuguese marine fungi, we screened for antimicrobial, antioxidant, enzymatic, and cytotoxic activities. Mycelia aqueous extracts, obtained by high pressure-assisted extraction, and methanolic extracts of culture media showed high antioxidant, antimicrobial, and cytotoxic activities. The mycelium extracts of Cladosporium rubrum showed higher antioxidant potential compared to extracts from other fungi. Mycelia and culture media extracts of Aspergillus affinis and Penicillium lusitanum inhibited the growth of Staphylococcus aureus, Kocuria rhizophila, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, including multiresistant strains. Penicillium lusitanum and Trichoderma aestuarinum inhibited the growth of clinical strains of Candida albicans, C. glabrata, C. parapsilosis, and C. tropicalis. All extracts from culture media were cytotoxic to Vero cells. Sea salt induced alterations in the mycelium’s chemical composition, leading to different activity profiles.

Word Entropy-Based Approach to Detect Highly Variable Genetic Markers for Bacterial Genotyping

Genotyping methods are used to distinguish bacterial strains from one species. Thus, distinguishing bacterial strains on a global scale, between countries or local districts in one country is possible. However, the highly selected bacterial populations (e.g., local populations in hospital) are typically closely related and low diversified. Therefore, currently used typing methods are not able to distinguish individual strains from each other. Here, we present a novel pipeline to detect highly variable genetic segments for genotyping a closely related bacterial population. The method is based on a degree of disorder in analyzed sequences that can be represented by sequence entropy. With the identified variable sequences, it is possible to find out transmission routes and sources of highly virulent and multiresistant strains. The proposed method can be used for any bacterial population, and due to its whole genome range, also non-coding regions are examined.

Four New Phloroglucinol-Terpene Adducts from the Leaves of Myrciaria cauliflora

Myrcauones A–D (1–4), four new phloroglucinol–terpene adducts were isolated from the leaves of Myrciaria cauliflora. Their structures with absolute configurations were elucidated by combination of spectroscopic analysis, single crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compound 1 was a rearranged isobutylphloroglucinol–pinene adduct featuring an unusual 2,3,4,4a,10,11-hexahydro-1H-3,11a-methanodibenzo[b,f]oxepin backbone. Compound 4 showed moderate antibacterial activity against Gram-positive bacteria including multiresistant strains. Graphic Abstract

High mortality by nosocomial infections caused by carbapenem-resistant P. aeruginosa in a referral hospital in Brazil: facing the perfect storm

Introduction. Carbapenem-resistant Pseudomonas aeruginosa is responsible for increased patient mortality. Gap Statement. Five and 30 day in-hospital all-cause mortality in patients with P. aeruginosa infections were assessed, followed by evaluations concerning potential correlations between the type III secretion system (TTSS) genotype and the production of metallo-β-lactamase (MBL). Methodology. This assessment comprised a retrospective cohort study including consecutive patients with carbapenem-resistant infections hospitalized in Brazil from January 2009 to June 2019. PCR analyses were performed to determine the presence of TTSS-encoding genes and MBL genes. Results. The 30-day and 5-day mortality rates for 262 patients were 36.6 and 17.9 %, respectively. The unadjusted survival probabilities for up to 5 days were 70.55 % for patients presenting exoU-positive isolates and 86 % for those presenting exo-negative isolates. The use of urinary catheters, as well as the presence of comorbidity conditions, secondary bacteremia related to the respiratory tract, were independently associated with death at 5 and 30 days. The exoS gene was detected in 64.8 % of the isolates, the presence of the exoT and exoY genes varied and exoU genes occurred in 19.3 % of the isolates. The exoU genotype was significantly more frequent among multiresistant strains. MBL genes were not detected in 92 % of the isolates. Conclusions. Inappropriate therapy is a crucial factor regarding the worse prognosis among patients with infections caused by multiresistant P. aeruginosa , especially those who died within 5 days of diagnosis, regardless of the genotype associated with TTSS virulence.

PSVIII-12 Estimations of treatment schemes efficiency of bacterial mastitis in dairy cow and antibiotic resistance of identified pathogens

The research was done on the herd (n = 3000) of cows of black-motley breed with an admixture of Holstein. At the first stage, the diagnosis was carried out by using the Keno test. There were selected 148 (4.9%) cow, which had of subclinical mastitis. For treatment, there were used the schemes tried and tested in the farm: (1) nisin, polymexin B, ketoprofen, methyl salicylate; (2) nisin, polymexin B, ketoprofen, ceftiofur; (3) amoxicillin, ketoprofen, methyl salicylate, prednisone. Before it, the allocation of pathogens was not carried out. After treatment the number of repeated cases of the disease reached 44.6%, which indicated the ineffectiveness of the treatment regimens used. At the second stage, samples of milk, nasal and vaginal mucus were taken from animals with a relapse of mastitis. Different pathogens were used to isolate pathogens (Staphylococcus aureus, Escherichia coli, Shigella spp., Enterococcus spp., Ps. aeruginosa). The extracted isolates were identified based on the cultural and biochemical properties. The results were interpreted on the recommendation of EUCAST. Of all the animals examined, they simultaneously detected in milk 3 pathogens in 37.8%, 2 pathogens in 40.9%, and only one pathogen was isolated in 21.3%. Moreover, S. aureus (84.8%), Ps. aeruginosa (62.1%), Enterococcus spp. (34.8%) was found in smears from the vagina. The sensitivity of the selected pathogens to antimicrobials showed that 73% of S. aureus strains were resistant to ≥6 antibiotics, 47% E. coli to ≥7, 34% Shigella spp. to ≥4 and 21% Ps. aeruginosa to ≥4. The use of antibiotics of different groups without isolating the pathogen and determining its sensitivity leads to the appearance of multiresistant strains of bacteria and culling animals from the herd. This work was supported by the Ministry of Science and Higher Education of Russia (AAAA-A18-118021590136-7) and the Russian Science Foundation (project 20-16-00106).

Guidelines for using antimicrobials in veterinary surgery

The indiscriminate use of antimicrobials in clinical and surgical routine is an upward reality among veterinarians. The emergence of multiresistant strains is one of the consequences of the irrational use of these drugs, causing an emergency worldwide health problem. By 2050, it is estimated that superbugs will kill about 10 million people worldwide, more than cancer. This paper aims to conduct a literature review on the topic and raise awareness of health professionals about the importance of rationality in the act of choosing the antimicrobial to be used, as well as assess the need or not to use them