Acta microbiologica et immunologica Hungarica最新文献

This study examined the prevalence and antibiotic resistance pattern of blaCTX-M extended-spectrum β-lactamase positive Salmonella species isolated from a hospital in Weifang. Salmonella strains were isolated from hospitalized patients from January 2018 to April 2023. Whole-genome sequencing was performed by Illumina platform. CTX-M-producing Salmonella were identified by Comprehensive Antibiotic Research Database (CARD). Strain susceptibility to six antimicrobial agents was assessed by BD Phoenix™ M50 System. MLST analysis confirmed sequence types and additionally, serotypes were determined by SeqSero2. Genetic environments of blaCTX-M genes were analyzed by Isfinder and BLASTn. Single nucleotide polymorphisms were used to construct a phylogenetic tree to analyze homology. A total of 34 CTX-M-producing Salmonella were detected. The most prevalent serotype was Salmonella enterica subsp. enterica 1,4,[5],12:i:- (14/34, 41.18%), belonging to ST34, followed by Salmonella Enteritidis (10/34, 29.41%), belonging to ST11. The highest resistance rate was detected to ampicillin (97.06%), followed by ceftriaxone (94.12%) and ceftazidime (58.83%). In CTX-M-producing Salmonella five types of blaCTX-M genes were identified, the most prevalent was blaCTX-M-55 (47.06%, 16/34), followed by blaCTX-M-14, blaCTX-M-65, blaCTX-M-125, and blaCTX-M-27 at 26.47% (9/34), 11.77% (4/34), 8.82% (3/34), and 5.88% (2/34), respectively. Apart from blaCTX-M, 40 antibiotic resistance genes were also detected, conveying resistance to multiple drugs and the most frequent genes were namely, mcr-1.1, aph(6)-Id, aph(3″)-Ib, oqxAB, qnrB6, qnrS1. According to genetic environment analysis, the insertion sequence ISEcp1 was prevalent upstream of the blaCTX-M gene. Our study demonstrates that multiple resistance genes are carried by clinical isolates of Salmonella spp. however, the dominant ESBL genotype is CTX-M-55, that is associated with ISEcp1.

We report a nosocomial outbreak caused by a multidrug-resistant carbapenemase-producing Klebsiella pneumoniae (MDRCPKp), that was detected in six patients admitted to the medical intensive care unit between 20th of December 2023 and 15th of January 2024 in Ankara, Turkey. The investigation of this outbreak was started on 29th of December 2023. During the outbreak 11 samples were collected from the six patients with MDRCPKp. Pulsed-field gel electrophoresis (PFGE) was performed to determine the genetic relatedness and clonality of MDRCPKp strains. MDRCPKp was isolated in the tracheal aspiration culture, blood, urine, and screening samples. Five patients with MDRCPKp colonization developed healthcare-associated infection. In one patient MDRCPKp was isolated from tracheal aspirate and the screening cultures were considered as colonization not infection. PFGE analysis revealed that all isolates belonged to the same K. pneumoniae clone. MDRCPKp strain of this outbreak exhibited multidrug resistance and co-produced OXA-48 and NDM-1. This outbreak ended after application of strict infection control measures. An outbreak of MDRCPKp can occur in hospitals, especially in the intensive care units; thus, it should be detected early by infection control teams. A strong collaboration between infection control team and microbiology laboratory is essential to cope with MDR bacterial outbreaks in hospitals.

Hospital acquired infections greatly affect recovery and survival in pediatric surgical patients. We evaluated prevalence and antimicrobial resistance of ESKAPE pathogens in neonates and infants subjected to cardiac surgery in a tertiary hospital in Central Kazakhstan between 2019 and 2023 (2,278 patients) using routine methods of microbiological detection. ESKAPE pathogens were found in 1,899 out of 2,957 samples (Staphylococcus aureus - 35.3%, Klebsiella pneumoniae - 27.8%, Acinetobacter baumannii - 14.5%, Pseudomonas aeruginosa - 12.4%, Enterobacter sp. - 8.8%, Enterococcus faecium - 1.2%). The total prevalence of ESKAPE increased significantly from 45.1 to 76.9% (P = 0.005) during the study period. The resistance significantly increased in methicillin-resistant S. aureus (MRSA, from 13.7 to 41.9%, P = 0.041) but decreased in carbapenem-resistant P. aeruginosa (from 64.3 to 37.7%, P = 0.037) and carbapenem-resistant A. baumannii (from 48.5 to 19.1%, P = 0.039). Gradual but non-significant changes were shown in third-generation cephalosporin resistant K. pneumoniae (from 63.6 to 45.2%) and carbapenem-resistant K. pneumoniae (from 0 to 8.3%). The relative prevalence of ESKAPE pathogens steadily increased in our pediatric cardiac surgery patients in 2019-2023. The most frequent were S. aureus, K. pneumoniae, and A. baumannii, with dramatically increasing tendencies for MRSA. Our results highlight the necessity for a well-designed infection control strategy and constant microbiological monitoring in pediatric cardiac surgery departments.

The Acidaminococcus genus is a part of the normal flora in gastrointestinal tract. It is a strictly anaerob Gram-negative coccus that is rarely pathogenic. We report the case of a 58-year-old man, who presented to surgery department A of the Charles Nicolle hospital, complaining of a wide inflammatory lesion in the anterior abdominal wall evolving for two weeks. Patient's anamnestic data included smoking, hypertension, and diabetes mellitus with poor compliance. The patient underwent flattening with excision of necrotic tissues and surgical drainage using a DELBET blade. Empirical antibiotic therapy with imipenem 1gx3/d, teicoplanin 400 mg 1 inj x2/d and gentamicin 400 mg 1 inj/d was administered pending bacteriological results. The bacteriological examination of a sample of necrotic tissue, after 72 h of incubation at 37 °C in anaerobic atmosphere, was able to detect a Gram-negative coccus, that the VITEK2 ANC system identified as Actinomyces canis with an accuracy of 80%. Whole genome sequencing was subsequently performed, that identified Acidaminococcus sp. AM33-14BH and demonstrated the following resistance genes: cfxa, tet(X) and tet(Q). An antibiogram for anaerobes was performed showing that the strain was resistant to amoxicillin but sensitive to amoxicillin-clavulanic acid, piperacillin-tazobactam, ertapenem, imipenem, meropenem and rifampin. Patient's condition improved after treatment with imipenem for 2 weeks, followed by oral amoxicillin-clavulanic acid for 16 days.This work highlights the role of molecular biology in the diagnosis of infections caused by anaerobes. Although the Vitek 2 ANC card provides rapid and acceptable identification of the most common anaerobic bacteria, improvements are needed for the identification of bacteria in the genera Acidaminococcus and Actinomyces.

Delftia acidovorans is an aerobic, non-fermenting Gram-negative bacterium (NFGNB), found in soil, water and hospital environments. It is rarely clinically significant, most commonly affecting hospitalized or immunocompromised patients. The present study aimed to explore the genomic characteristics of a Bulgarian clinical D. acidovorans isolate (designated Dac759) in comparison to all strains of this species with available genomes in the NCBI Genome database (n = 34). Dac759 was obtained in 2021 from the sputum of a 65-year-old female immunocompetent outpatient with bronchitis. Species identification using MALDI-TOF mass spectrometry, antimicrobial susceptibility testing, whole-genome sequencing (WGS), and phylogenomic analysis were performed. The isolate demonstrated high-level resistance to colistin (16 mg L-1); resistance to gentamicin; reduced susceptibility to piperacillin, piperacillin-tazobactam, ceftazidime, cefepime, ciprofloxacin, and levofloxacin; and susceptibility to imipenem, meropenem, amikacin, and tobramycin. The observed genome size (6.43 Mb) and GC content (66.76%) were comparable with the accessible data from sequenced D. acidovorans genomes. A limited number of resistance determinants were identified in the assembled genome as follows: blaOXA-459, emrE, oqxB, and mexCD-oprJ. The phylogenomic analysis indicated a high heterogenicity of the included D. acidovorans genomes. In conclusion, to the best of our knowledge, this is the first documented case of a clinically relevant D. acidovorans isolate in Bulgaria. Unlike the majority of reports in the literature, Dac759 affected a patient with no malignancies or other preexisting comorbidities. With this in mind, its genome sequence is a valuable resource for the fundamental study of uncommon bacterial pathogens of public health importance.

Although the relationship between vaginal microorganisms and fertility has been well established, only few studies have investigated vaginal microorganisms in women undergoing in vitro fertilization (IVF). Our aim was to study the differences in vaginal microbiota between infertile women with repeated implantation failure (RIF) and those who achieved clinical pregnancy in their first frozen embryo transfer cycle. We compared the vaginal microbiota of patients with a history of RIF (n = 37) with that of the control group (n = 43). Following DNA extraction, metagenomic sequencing was employed for the analysis of alpha and beta diversities, distinctions in bacterial species, and the functional annotation of microbial genes. Furthermore, disparities between the two groups were revealed. Alpha diversity analysis revealed that the Shannon index was higher in the RIF group (P < 0.05). There were differences in the beta diversity between groups (P = 0.16). At the bacterial family level, the relative abundance of Actinomycetaceae (P = 0.013) and Ruminococcaceae (P = 0.013) were significantly higher in the RIF group. At the genus level, the abundances of Actinomyces (P = 0.028) and Subdoligranulum (P = 0.013) were significantly higher in the RIF group. At the species level, the abundances of Prevotella timonensis (P = 0.028), Lactobacillus jensenii (P = 0.049), and Subdoligranulum (P = 0.013) were significantly higher in the RIF group. Significant differences in family, genus, species, alpha and beta diversity were observed in the vaginal microbiota between groups. Notably, among these findings, the Subdoligranulum genus emerged as the most prominent correlating factor.

The aim of this study is to evaluate the antimicrobial susceptibility of invasive isolates of Serratia marcescens, associated with blood stream infections (BSIs) in patients hospitalized in Varna University Hospital, Bulgaria, as well as to identify the genetic mechanisms responsible for 3rd generation cephalosporin and carbapenem-resistance among these isolates. A total of 45 consecutive S. marcescens isolates, obtained from blood cultures of 45 patients with BSIs, hospitalized during an 8-year period (2016-2023) were included. Species identification and antimicrobial susceptibility testing were done by Phoenix (BD, USA) and Vitek 2 (BioMerieux, France) systems and the results were interpreted according to EUCAST guidelines. The genetic mechanisms of beta-lactam resistance were studied by PCR. During the study period, a total of 45 patients were diagnosed with S. marcescens-associated BSIs. All infections were defined as nosocomial, predominantly intensive care unit-acquired (42.2%) and 28.8% were central venous catheter-associated. The following antimicrobial resistance rates were found: ceftriaxone, piperacillin/tazobactam, 57.8%; ceftazidime, 55.6%; cefepime, trimethoprime/sulfamethoxazole, 53.3%; gentamicin, 48.8%; ciprofloxacin, 44.5%; amikacin, 15.6%; carbapenems, 2.2%. The blaCTX-M was identified in 88.9% of the tested 3rd generation cephalosporin resistant isolates. Among these, 50% were also blaTEM positive. The single carbapenem-resistant isolate harboured blaKPC, blaCTX-M1/9, blaCMY-2 and blaTEM. This study demonstrates S. marcescens as a problematic nosocomial pathogen and we report a KPC-producing S. marcescens clinical isolate from a BSI in Bulgaria.

Klebsiella pneumoniae is an opportunistic pathogen and it can cause human mucosal lesions through the intestine, leading to bacteremia and abscess formation in liver and spleen. Previous studies have shown that K. pneumoniae can enter or cross cells through the intestinal epithelium, but the mechanism is unknown. In this study, we treated the intestinal epithelial cell line Caco-2 with KP1195, a clinically isolated strain with high adhesion and invasion of intestinal epithelial cells. The results showed that the treatment of K. pneumoniae could increase the expression of integrin gene and further disrupt the changes of cytoskeleton. Treating Caco-2 with cytoskeletal inhibitor cytorelaxin D can significantly increase the efficiency of K. pneumoniae invading Caco-2 cells. These data suggest that disruption of the cytoskeleton through integrins may be one of the mechanisms by which K. pneumoniae increases intracellular invasion. This study provides a theoretical basis for further understanding of the mechanism of K. pneumoniae entering intestinal epithelial cells.

Urinary tract infections are becoming difficult to treat every year due to antibiotic resistance. Uropathogenic Escherichia coli (UPEC) isolates pose a threat with a combined expression of multidrug-resistance and biofilm formation. ST131 clone is a high-risk pandemic clone due to its strong association with antimicrobial resistance, which has been reported frequently in recent years. This study aims to define risk factors, clinical outcomes, and bacterial genetics associated with ST131/O25b UPEC. In this study, antibiotic susceptibility and species-level identification of 61 clinical E. coli strains were determined by automated systems. Detection of extended-spectrum beta-lactamases was assessed by double-disk synergy test. Biofilm formation was quantified by spectrophotometric method. Virulence genes (iutA, sfa cnf-1, iroN, afa, papA, fimA), antibiotic resistance genes (blaCTX-M, blaTEM, blaSHV, blaOXA, qnrA, qnrB, qnrS, ant(2')-Ia, ant(3)-Ia, aac(3)-IIa, mcr-1, mcr-2, mcr-3, mcr-4) were investigated by PCR. The following beta-lactamase genes were identified, blaTEM (n = 53, 86.8%), blaCTX-M (n = 59, 96.7%), blaSHV (n = 47, 77.0%), and blaOXA-1 (n = 27, 44.2%). Our data revealed that 93.4% of (57/61) E. coli isolates were biofilm-producers. O25pabBspe and trpA2 were investigated for the presence of ST131/O25b clone. Among multidrug resistant isolates, co-existence of O25pabBspe and trpA2 was detected in 29 isolates (47.5%). The fimH30 and H30Rx subclones were detected in four isolates that are strong biofilm-producers. These results suggest that clinical E. coli strains may become reservoirs of virulence and antibiotic resistance genes. This study demonstrates a significant difference in biofilm formation between E. coli ST131 and non-ST131 isolates. Moreover, 86.21% (n = 25) of ST131 isolates produced strong to moderate biofilms, while only 43.75% (n = 14) of non-ST131 isolates showed the ability to form strong biofilms. Presence of iutA and fimA genes in the majority of ST131 strains showed an important role in biofilm formation. These findings suggest application of iutA and fimA gene suppressors in treatment of infections caused by biofilm-producing drug-resistant ST131 strains.

Oral Squamous cell carcinoma (OSCC) is the 14th most frequent cancer with 300,000 new cases and 100,000 deaths reported annually. Even with advanced therapy, the treatment outcomes are poor at advanced stages of the disease. The diagnosis of early OSCC is of paramount clinical value given the high mortality rate associated with the late stages of the disease. Recently, the role of microbiome in the disease manifestation, including oral cancer, has garnered considerable attention. But, to establish the role of bacteria in oral cancer, it is important to determine the differences in the colonization pattern in non-tumour and tumour tissues. In this study, 16S rRNA based metagenomic analyses of 13 tumorous and contralateral anatomically matched normal tissue biopsies, obtained from patients with advanced stage of OSCC were evaluated to understand the correlation between OSCC and oral microbiome. In this study we identified Fusobacterium, Prevotella, Capnocytophaga, Leptotrichia, Peptostreptococcus, Parvimonas and Bacteroidetes as the most significantly enriched taxa in OSCC lesions compared to the non-cancerous tissues. Further, PICRUSt2 analysis unveiled enhanced expression of metabolic pathways associated with L-lysine fermentation, pyruvate fermentation, and isoleucine biosynthesis in those microbes associated with OSCC tissues. These findings provide valuable insights into the distinctive microbial signatures associated with OSCC, offering potential biomarkers and metabolic pathways underlying OSCC pathogenesis. While our focus has primarily centred on microbial signatures, it is essential to recognize the pivotal role of host factors such as immune responses, genetic predisposition, and the oral microenvironment in shaping OSCC development and microbiome composition.