Acinetobacter baumannii thrives within eukaryotic cells, influencing persistence, treatment approaches, and progression of disease. We probed epithelial cell invasion by A. baumannii and the influence of antibodies raised to outer membrane protein 34 (Omp34) on epithelial interactions. We expressed and purified recombinant Omp34 and induced anti-Omp34 antibodies in Bagg albino or BALB/c mice. Omp34 was evaluated for acute toxicity in mice through histological analysis of six organs. The host cell line, A549, was exposed to both A. baumannii 19606 and a clinical isolate. The study also investigated serum resistance, adherence, internalization, and proliferation of A. baumannii in A549 cells, with and without anti-Omp34 sera, utilizing cell culture techniques and light microscopy. A549 cell viability was evaluated by A. baumannii challenge and exposure to anti-Omp34 sera. Actin disruption experiments using cytochalasin D probed microfilament and microtubule roles in A. baumannii invasion. Omp34 prompted antibody production without toxicity in mice. The serum showed bactericidal effects on both strains. Additionally, both A. baumannii strains were found to form biofilms. Omp34 serum was observed to decrease biofilm formation, bacterial adherence, internalization, and proliferation in A549 cells. Furthermore, the use of anti-Omp34 serum enhanced the post-infection survival of the host cell. Pre-exposure of A549 cells to cytochalasin D reduced bacterial internalization, highlighting the role of actin polymerization in the invasion process. Microscopic analysis revealed various interactions, such as adherence, membrane alterations, vacuolization, apoptosis, and cellular damage. Anti-Omp34 serum-exposed A549 cells were protected and showed reduced damage. The findings reveal that A. baumannii can significantly multiply intracellularly within host cells. This suggests the bacterium's ability to establish an environment conducive to its replication by preventing fusion with degradative lysosomes and inhibiting acidification. This finding contributes to the understanding of A. baumannii's intracellular persistence and highlights the role of Omp34 in influencing apoptosis, autophagy, and bacterial adherence, which may impact the development of effective treatments against A. baumannii infections.

• MeSH
• Acinetobacter baumannii * fyziologie   imunologie   patogenita   MeSH
• bakteriální adheze * MeSH
• biofilmy růst a vývoj   MeSH
• buňky A549 MeSH
• epitelové buňky mikrobiologie   MeSH
• infekce bakteriemi rodu Acinetobacter * mikrobiologie   imunologie   MeSH
• lidé MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• protilátky bakteriální * imunologie   MeSH
• viabilita buněk MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Cíl: Úraz elektrickým proudem z vysokého napětí je jedním z nejzávažnějších úrazů, se kterými se můžeme v moderní medicíně setkat. Často bývá spojený s více následky a vysokou náchylností k infekčním komplikacím. Tito pacienti jsou přijímáni do specializovaných popáleninových center a vyžadují rozsáhlou multidisciplinární spolupráci. V této studii se snažíme odhalit prevalenci, typy a charakteristiky mikrobiálních infekcí, které se vyvíjejí po vysokonapěťovém elektrotraumatu, a identifikovat rizikové faktory, které mohou přispívat k náchylnosti pacientů k infekcím. Materiál a metodika: Pro účely této publikace byla zpracována data všech 37 pacientů hospitalizovaných na jednotce intenzivní péče Kliniky popálenin a plastické chirurgie FN Brno s diagnózou úraz elektrickým proudem vysokým napětím v letech 2006–2016. Otisky a stěry z exfoliovaných oblastí byly opakovaně odebírány k mikrobiální analýze spolu s tracheobronchiálním aspirátem, sputem nebo bronchoalveolární laváží, močí a periferní krví. Získaná data byla zpětně analyzována. Výsledky: Mezi 37 pacienty byl medián věku 31,9 s průměrnou dobou hospitalizace 44,3 dne a úmrtností 8,1 %. Na umělé plicní ventilaci bylo závislých celkem 28 osob. Výskyt infekčních komplikací se v průběhu hospitalizace liší podle místa kultivace odběru a doby strávené v nemocnici. U 97,3 % pacientů se vyvinula infekce alespoň v jednom tělesném kompartmentu. V 88,8 % případů byla multipatogenní a ve 41,6 % se rozvinul septický stav. V naší studijní kohortě dominovaly G+ nad G-kmeny. Nejčastějšími zástupci z G+ spektra byli koaguláza negativní stafylokoky (97 %), Staphylococcus aureus (57 %), Enterococcus fecalis et faecium (51 %). V G-spektru bylo pořadí následující: Klebsiella pneumoniae (46 %), Pseudomonas aeruginosa (41 %), Escherichia coli (35 %) a Acinetobacter baumannii (18,9 %). Nejčastější pozorovanou infekcí byla infekce popálenin (BWI), následovaná infekcemi krevního řečiště (BSI), infekcemi dolních cest dýchacích (LRTI) a infekcemi močových cest (UTI), primárně způsobené G+ patogeny. Je pozoruhodné, že delší doba hospitalizace byla spojena s rostoucí prevalencí G-patogenů, zejména K. pneumoniae, P. aeruginosa a A. baumannii, které vykazovaly vysoký stupeň antimikrobiální rezistence. Závěr: Tato studie poskytuje podrobný pohled na výskyt a následky úrazů elektrickým proudem s vysokým napětím na Moravě v průběhu desetiletí. Faktory významně ovlivňující přežití a závažnost výsledků zahrnovaly celkovou plochu popálenin, popáleniny v celé tloušťce, inhalační poranění a potřebu tracheostomie. Studie je však limitována relativně malou velikostí vzorku, dlouhou dobou sběru dat s potenciálními změnami v klinické praxi a jednocentrovým designem, což může ovlivnit zobecnění nálezů. K ověření těchto výsledků a zpřesnění strategií prevence infekcí u této populace pacientů jsou zapotřebí další multicentrické studie.

Background and Aim: High voltage electrotrauma is one of the most serious injuries we can encounter in modern medicine, often associated with multiple disabilities and high susceptibility to infectious complications. These patients are admitted to specialized burn centers and require extensive multidisciplinary collaboration. In this study, we aim to uncover the prevalence, types and characteristics of microbial infections that develop in the aftermath of high voltage electrotrauma and to identify risk factors that may contribute to patients’ susceptibility to infections. Material and Methods: For the purposes of this publication, data of all 37 patients hospitalized in the intensive care unit of the Department of Burns and Plastic Surgery of the University Hospital in Brno with a diagnosis of high-voltage electrical injury between 2006–2016 were processed. Imprints and swaps from exfoliated areas were repeatedly taken for microbial analysis, together with tracheobronchial aspirate fluid, sputum, or bronchoalveolar lavage, urine and peripheral blood. The obtained data were analysed retrospectively. Results: Among the 37 patients, the median age was 31.9, with an average hospital stay of 44.3 days and a mortality rate of 8.1%. A total of 28 individuals were dependent on artificial lung ventilation. The incidence of infectious complications varies during the hospitalization period according to the location of sampling cultivation and time spent at the hospital. 97.3% of patients developed infection in at least one body compartment. In 88.8% of cases, it was multipathogenic and in 41.6% a septic condition developed. In our study cohort, G+ dominated over Gstrains. Most common representatives from G+ spectrum were Coagulase negative Staphylococci (97%), Staphylococcus aureus (57%), Enterococcus fecalis et faecium (51%). In Gspectrum, the order was as followed: Klebsiella pneumoniae (46%), Pseudomonas aeruginosa (41%), Escherichia coli (35%) and Acinetobacter baumannii (18.9%). The most common infection observed was burn wound infection (BWI), followed by bloodstream infections (BSI), lower respiratory tract infections (LRTI), and urinary tract infections (UTI), primarily caused by G+ pathogens. Notably, an increased hospital stay duration was associated with a rising prevalence of Gpathogens, particularly K. pneumoniae P. aeruginosa and A. baumannii which exhibited a high degree of antimicrobial resistance. Conclusion: This study provides a detailed insight into the occurrence and consequences of high-voltage electrical injuries in Moravia over a decade. Factors significantly impacting survival and severity of outcomes included total burn surface area, full-thickness burns, inhalation injury, and the need for tracheostomy. However, the study is limited by its relatively small sample size, long data collection period with potential changes in clinical practice, and single-center design, which may affect the generalizability of the findings. Further multicentric studies are needed to validate these results and refine infection prevention strategies in this patient population.

Acinetobacter baumannii (AB) is an opportunistic pathogen with growing clinical relevance due to its increasing level of antimicrobial resistance in the last few decades. In the event of an AB hospital outbreak, fast detection and localization of the pathogen is crucial, to prevent its further spread. However, contemporary diagnostic tools do not always meet the requirements for rapid and accurate diagnosis. For this reason, we report here the possibility of using gallium-68 labeled siderophores, bacterial iron chelators, for positron emission tomography imaging of AB infections. In our study, we radiolabeled several siderophores and tested their in vitro uptake in AB cultures. Based on the results and the in vitro properties of studied siderophores, we selected two of them for further in vivo testing in infectious models. Both selected siderophores, ferrioxamine E and ferrirubin, showed promising in vitro characteristics. In vivo, we observed rapid pharmacokinetics and no excessive accumulation in organs other than the excretory organs in normal mice. We demonstrated that the radiolabeled siderophores accumulate in AB-infected tissue in three animal models: a murine model of myositis, a murine model of dorsal wound infection and a rat model of pneumonia. These results suggest that both siderophores radiolabeled with Ga-68 could be used for PET imaging of AB infection.

• MeSH
• Acinetobacter baumannii * MeSH
• infekce bakteriemi rodu Acinetobacter * diagnostické zobrazování   mikrobiologie   MeSH
• krysa rodu rattus MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• pozitronová emisní tomografie * metody   MeSH
• radioizotopy galia * chemie   MeSH
• siderofory * chemie   farmakokinetika   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

The relative inhibitory activities of diazabicyclooctanes (avibactam, relebactam, zidebactam, nacubactam, durlobactam), boronic acid derivatives (vaborbactam, taniborbactam, xeruborbactam), and penicillin-based sulfone derivative enmetazobactam were evaluated against several intrinsic and acquired class C β-lactamases. By contrast to vaborbactam and enmetazobactam, taniborbactam, xeruborbactam, and all diazabicyclooctanes demonstrated effective activities against most AmpC enzymes. Notably, durlobactam exhibited the most pronounced inhibitory effect. Interstingly, the chromosomal AmpC of Acinetobacter baumannii was the least sensitive enzyme to the newly developed β-lactamase inhibitors.

• MeSH
• Acinetobacter baumannii * účinky léků   enzymologie   MeSH
• antibakteriální látky * farmakologie   chemie   MeSH
• azabicyklické sloučeniny * farmakologie   chemie   MeSH
• bakteriální proteiny * antagonisté a inhibitory   metabolismus   MeSH
• beta-laktamasy * metabolismus   MeSH
• bicyklické sloučeniny heterocyklické farmakologie   chemie   MeSH
• cyklooktany MeSH
• inhibitory beta-laktamasy * farmakologie   chemie   MeSH
• kyseliny boronové * farmakologie   chemie   MeSH
• laktamy MeSH
• mikrobiální testy citlivosti * MeSH
• peniciliny farmakologie   chemie   MeSH
• piperidiny MeSH
• sulfony farmakologie   chemie   MeSH
• Publikační typ
• časopisecké články MeSH

Peptides that form transmembrane barrel-stave pores are potential alternative therapeutics for bacterial infections and cancer. However, their optimization for clinical translation is hampered by a lack of sequence-function understanding. Recently, we have de novo designed the first synthetic barrel-stave pore-forming antimicrobial peptide with an identified function of all residues. Here, we systematically mutate the peptide to improve pore-forming ability in anticipation of enhanced activity. Using computer simulations, supported by liposome leakage and atomic force microscopy experiments, we find that pore-forming ability, while critical, is not the limiting factor for improving activity in the submicromolar range. Affinity for bacterial and cancer cell membranes needs to be optimized simultaneously. Optimized peptides more effectively killed antibiotic-resistant ESKAPEE bacteria at submicromolar concentrations, showing low cytotoxicity to human cells and skin model. Peptides showed systemic anti-infective activity in a preclinical mouse model of Acinetobacter baumannii infection. We also demonstrate peptide optimization for pH-dependent antimicrobial and anticancer activity.

• MeSH
• Acinetobacter baumannii účinky léků   MeSH
• antibakteriální látky farmakologie   chemie   chemická syntéza   MeSH
• antimikrobiální peptidy chemie   farmakologie   chemická syntéza   MeSH
• kationické antimikrobiální peptidy farmakologie   chemie   chemická syntéza   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• protinádorové látky * farmakologie   chemie   chemická syntéza   MeSH
• racionální návrh léčiv * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Among the non-traditional antibacterial agents in development, only a few targets critical Gram-negative bacteria such as carbapenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii or cephalosporin-resistant Enterobacteriaceae. Endolysins and their genetically modified versions meet the World Health Organization criteria for innovation, have a novel mode of antibacterial action, no known bacterial cross-resistance, and are being intensively studied for application against Gram-negative pathogens. METHODS: The study presents a multidisciplinary approach, including genetic engineering of LysECD7-SMAP and production of recombinant endolysin, its analysis by crystal structure solution following molecular dynamics simulations and evaluation of antibacterial properties. Two types of antimicrobial dosage forms were formulated, resulting in lyophilized powder for injection and hydroxyethylcellulose gel for topical administration. Their efficacy was estimated in the treatment of sepsis, and pneumonia models in BALB/c mice, diabetes-associated wound infection in the leptin receptor-deficient db/db mice and infected burn wounds in rats. RESULTS: In this work, we investigate the application strategies of the engineered endolysin LysECD7-SMAP and its dosage forms evaluated in preclinical studies. The catalytic domain of the enzyme shares the conserved structure of endopeptidases containing a putative antimicrobial peptide at the C-terminus of polypeptide chain. The activity of endolysins has been demonstrated against a range of pathogens, such as Klebsiella pneumoniae, A. baumannii, P. aeruginosa, Staphylococcus haemolyticus, Achromobacter spp, Burkholderia cepacia complex and Haemophylus influenzae, including those with multidrug resistance. The efficacy of candidate dosage forms has been confirmed in in vivo studies. Some aspects of the interaction of LysECD7-SMAP with cell wall molecular targets are also discussed. CONCLUSIONS: Our studies demonstrate the potential of LysECD7-SMAP therapeutics for the systemic or topical treatment of infectious diseases caused by susceptible Gram-negative bacterial species and are critical to proceed LysECD7-SMAP-based antimicrobials trials to advanced stages.

• MeSH
• antibakteriální látky farmakologie   aplikace a dávkování   MeSH
• endopeptidasy * farmakologie   aplikace a dávkování   MeSH
• gramnegativní bakteriální infekce * farmakoterapie   MeSH
• gramnegativní bakterie * účinky léků   MeSH
• krysa rodu rattus MeSH
• myši inbrední BALB C * MeSH
• myši MeSH
• proteinové inženýrství metody   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Bacterial resistance surveillance is one of the main outputs of microbiological laboratories and its results are important part of antimicrobial stewardship (AMS). In this study, the susceptibility of specific bacteria to selected antimicrobial agents was tested. The susceptibility of 90 unique isolates of pathogens of critical priority obtained from clinically valid samples of ICU patients in 2017-2021 was tested. 50% of these fulfilled difficult-to-treat resistance (DTR) criteria and 50% were susceptible to all antibiotics included in the definition. 10 Enterobacterales strains met DTR criteria, and 2 (20%) were resistant to colistin (COL), 2 (20%) to cefiderocol (FCR), 7 (70%) to imipenem/cilastatin/relebactam (I/R), 3 (30%) to ceftazidime/avibactam (CAT) and 5 (50%) to fosfomycin (FOS). For Enterobacterales we also tested aztreonam/avibactam (AZA) for which there are no breakpoints yet. The highest MIC of AZA observed was 1 mg/l, MIC range in the susceptible cohort was 0.032-0.064 mg/l and in the DTR cohort (incl. class B beta-lactamase producers) it was 0.064-1 mg/l. Two (13.3%) isolates of Pseudomonas aeruginosa (15 DTR strains) were resistant to COL, 1 (6.7%) to FCR, 13 (86.7%) to I/R, 5 (33.3%) to CAT, and 5 (33.3%) to ceftolozane/tazobactam. All isolates of Acinetobacter baumannii with DTR were susceptible to COL and FCR, and at the same time resistant to I/R and ampicillin/sulbactam. New antimicrobial agents are not 100% effective against DTR. Therefore, it is necessary to perform susceptibility testing of these antibiotics, use the data for surveillance (including local surveillance) and conform to AMS standards.

• MeSH
• antibakteriální látky * farmakologie   terapeutické užití   MeSH
• azabicyklické sloučeniny * MeSH
• aztreonam MeSH
• cefalosporiny * MeSH
• cefiderokol MeSH
• gramnegativní bakterie MeSH
• kolistin farmakologie   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• Pseudomonas aeruginosa MeSH
• retrospektivní studie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• Acinetobacter baumannii účinky léků   MeSH
• antibakteriální látky farmakologie   terapeutické užití   MeSH
• antibiotická rezistence MeSH
• cefiderokol * farmakologie   terapeutické užití   MeSH
• gramnegativní bakterie účinky léků   MeSH
• klinická studie jako téma MeSH
• lidé MeSH
• Stenotrophomonas maltophilia účinky léků   MeSH
• Check Tag
• lidé MeSH

Necrotizing fasciitis is a life-threatening skin and soft tissue infection associated with high morbidity and mortality in adult patients. This infection can present as either type 1 infection caused by a mixed microflora (Streptococci, Enterobacteriacae, Bacteroides sp., and Peptostreptococcus sp.), most commonly developing in patients after surgery or in diabetic patients, or as type 2. The latter type is monomicrobial and, usually, caused by group A Streptococci. Rarely, this type can be also caused by other pathogens, such as Vibrio vulnificus. V vulnificus is a small mobile Gram-negative rod capable of causing 3 types of infections in humans-gastroenteritis, primary infection of the vascular bed, and wound infections. If infecting a wound, V vulnificus can cause a life-threatening condition-necrotizing fasciitis. We present a rare case of necrotizing fasciitis developing after an insect bite followed by exposure to the seawater. Rapid propagation of the infectious complication in the region of the right lower limb led to a serious consideration of the necessity of amputation. Due to the clearly demarcated necroses and secondary skin and soft tissue infection caused by a multiresistant strain of Acinetobacter baumannii, we, however, resorted to the use of selective chemical necrectomy using 40% benzoic acid-a unique application in this kind of condition. The chemical necrectomy was successful, relatively gentle and thanks to its selectivity, vital parts of the limb remained preserved and could have been subsequently salvaged at minimum blood loss. Moreover, the antimicrobial effect of benzoic acid led to rapid decolonization of the necrosis and wound bed preparation, which allowed us to perform defect closure using split-thickness skin grafts. The patient subsequently healed without further complications and returned to normal life.

• MeSH
• Acinetobacter baumannii * MeSH
• dospělí MeSH
• fasciitida nekrotizující * diagnóza   MeSH
• infekce bakteriemi rodu Vibrio * komplikace   MeSH
• infekce měkkých tkání * diagnóza   komplikace   MeSH
• lidé MeSH
• Vibrio vulnificus * MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

A small receptor molecule composed of a porphyrin core with tetrakis-ammonium glycine pickets (liptin 3e) appears to target anionic phosphatidylglycerol (PG) lipid head groups through multifunctional binding-pocket complementarity. Although a major component of bacterial cell membranes, PG is not widely found in animal cells, making PG potentially selective for bacterial targeting. Growth of microbial isolates was monitored in liquid cultures treated with liptin 3e by dilution plate counts and turbidity. Inhibition of growth by liptin 3e was observed for the ESKAPE human pathogens (Enterobacter aerogenes, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterococcus faecium), Escherichia coli, Mycobacterium smegmatis, Streptococcus sobrinus, and methicillin-resistant S. aureus (MRSA), with certain species suppressed at <1 μg/mL (sub-μM) concentrations. Prolonged lag phases were observed, although cell viability was mainly unaffected, suggesting that liptin treatment caused bacteriostasis. Cultures treated with liptin 3e eventually recovered, resumed growth, and reached the same final densities as untreated cultures. Growth of the fungus Candida albicans was not appreciably inhibited by liptin 3e. If liptins exhibit bacteriostasis through broad extracellular binding to PG head groups, thereby disrupting cellular processes, liptins may be considered for development into preclinical drug candidates or be useful as a targeting system for molecular beacons or antibacterial drugs.

• MeSH
• antibakteriální látky farmakologie   MeSH
• Enterococcus faecium * MeSH
• Escherichia coli MeSH
• fosfatidylglyceroly MeSH
• lidé MeSH
• methicilin rezistentní Staphylococcus aureus * MeSH
• mikrobiální testy citlivosti MeSH
• receptory umělé * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH