Acta microbiologica et immunologica Hungarica最新文献

Recent scientific research has indicated that the gut microbiota constitutes a nuanced, diverse ecosystem of microorganisms that have gained significant attention due to its crucial involvement in shaping human health and diseases. In particular, the gut microbiota plays a pivotal role in cancer prevention, and disturbances in its composition and function, known as dysbiosis, that have been linked to an increased risk of developing various malignancies. The gut microbiota exerts a myriad of effects on the production of anti-cancer compounds, the host's immune system and inflammation, underscoring its crucial involvement in cancer. Additionally, recent studies have shown that the gut microbiota has a role in the development of cancer, influencing cancer risk, co-infections, disease progression, and treatment response. The observation of reduced efficacy of immunotherapy in patients receiving antibiotic treatment indicates a substantial influence of the microbiota in mediating the toxicity and response of cancer therapy, notably immunotherapy, and its immune-related side effects. A growing body of research has focused on cancer treatments that target the microbiome, including probiotics, dietary modifications, and faecal microbiota transplantation (FMT). The forthcoming era of personalised cancer therapies is anticipated to prioritise tumor evolution, molecular and phenotypic heterogeneity, and immunological profiling, with gut microbiota assuming a pivotal position in this domain. This review aims to offer clinicians a comprehensive perspective on the microbiota-cancer axis, including its influence on cancer prevention and therapy and highlights the importance of integrating microbiome science into the design and implementation of cancer therapies.

Efflux pumps play an important role in the emergence of antibiotic-resistant Pseudomonas aeruginosa strains. The present study aimed to assess the expression of the MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY-OprM efflux pumps in carbapenem-resistant and multidrug-resistant (MDR) P. aeruginosa strains isolated from clinical specimens between June 2019 and January 2022 in Ardabil city. The presence of efflux pump-encoding genes, i.e. mexA, mexC, mexE, and mexY, was assessed using the polymerase chain reaction (PCR) technique in 48 carbapenem-resistant and MDR P. aeruginosa strains. Real-time reverse transcription PCR was employed to evaluate the expression levels of mexA, mexC, mexE, and mexY genes. All 48 carbapenem-resistant and MDR P. aeruginosa strains harbored efflux pump-encoding genes including mexA, mexC, mexE, and mexY according to the PCR results. Overexpression of the MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY-OprM efflux pumps was detected in 75% (n = 36), 83.3% (n = 40), 10.4% (n = 5) and 41.6% (n = 20) of the clinical isolates of P. aeruginosa, respectively. This study revealed that the presence and overexpression of efflux pumps are associated with the emergence of carbapenem-resistant and MDR P. aeruginosa strains. Therefore, research on efflux pump inhibitors of P. aeruginosa will be a worthwhile endeavor to increase the clinical efficiency of available antibiotics and prevent ensuing treatment failure.

We aimed to investigate the prevalence of carbapenemases in Enterobacterales strains isolated from urine specimens between July 2019 and July 2020.CIM and modified CIM tests were applied as well as detection of blaOXA-48, blaNDM, blaVIM, blaKPC and blaIMP genes was performed by multiplex PCR.One hundred fifty of 3,242 Enterobacterales strains were found to be carbapenem resistant and 46 were included in the study. Forty five (98%) of the 46 strains included in the study were Klebsiella spp. and one (2%) of them was Escherichia coli. Susceptibility to ceftazidime-avibactam, amikacin and gentamicin was 97%, 11% and 9%, respectively. Forty three (94%) isolates were found positive at 2 and 4 h with CIM test. Forty four (97%) strains were found positive at 4 h and 43 (94%) strains were found positive at 2 h with modified CIM test.While blaOXA-48, blaNDM and blaOXA-48 with blaNDM association were found in Klebsiella spp. isolates in 55%, 27% and 11%, respectively, blaVIM, blaKPC, blaIMP were not found. Only blaOXA-48 and blaNDM-1 were detected in the E. coli strain.None of the investigated genes were detected in three Klebsiella strains but with whole genome analysis the combination of blaOXA-534, blaCMY-99 and blaKPC-3 was found in the first strain, blaOXA-370 in the second strain and no resistance gene was found in the third strain.Ceftazidime-avibactam was found to be active against 97% of strains, and the most common resistance genes were blaOXA-48 and blaNDM-1. Previously undetected resistance genes have been identified in our country.

The incidence of infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) is increasing worldwide, and very limited number of effective antibiotics are available for therapy. In our study, the in vitro efficacy of meropenem/polymyxin B and meropenem/fosfomycin combinations against CRKP strains was investigated. The efficiency of meropenem/polymyxin B and meropenem/fosfomycin combinations was tested by checkerboard microdilution and checkerboard agar dilution methods, respectively, against 21 CRKP strains containing major carbapenem resistant genes (7 blaKPC, 7 blaOXA-48 gene, and 7 blaOXA-48+ blaNDM), and seven additional CRKP strains without carbapenemase genes.Among the 28 CRKP strains, the meropenem/polymyxin B combination was synergistic in ten (35.7%), partially synergistic in 12 (42.8%), and indifferent in six (21.4%) isolates. The meropenem/fosfomycin combination was found to be synergistic in three isolates (10.7%), partially synergistic in 20 (71.4%), and indifferent in five (17.8%). In 21 strains containing carbapenem resistance genes, meropenem/polymyxin B and meropenem/fosfomycin combinations exhibited synergistic/partial synergistic effects in 15 (71.4%) and 16 (76.2%) strains, respectively, compared to 100% synergistic/partial synergistic efficiency in both combinations in seven strains free of carbapenemase genes. No antagonistic effect was detected in either combination.Regardless of presence or absence of carbapenem resistance genes, meropenem/polymyxin B and meropenem/fosfomycin combinations both demonstrated high synergistic and partial synergistic activity against 78.4% and 82.1% of CRKP strains, respectively. Also, they have no antagonistic effects and can be used successfully to prevent therapeutic failure with monotherapy, according to our in vitro studies.

Little is known about the properties of the current strains of Staphylococcus aureus associated with human infections in Thailand. This study examined the rate of resistance to various antimicrobial agents, prevalence of virulence genes, and biofilm formation ability of 60 clinical S. aureus isolates from a single Thai hospital. Moreover, the Staphylococcus protein A gene (spa) type was determined among methicillin-resistant S. aureus (MRSA) isolates. Most methicillin-susceptible S. aureus isolates were susceptible to antimicrobials, whereas all MRSA isolates were resistant to erythromycin and clindamycin. The major virulence genes among the isolates were hla (100%), sec (26.7%), and hlb (20%). Meanwhile, 46.7% and 1.7% of the strains exhibited low-grade and high-grade biofilm formation, respectively. Our findings revealed the presence of spa types among MRSA isolates were: t032 (37.5%, 6/16), t088 (25%, 4/16), t001 (12.5%, 2/16), t008 (6.25%, 1/16), t034 (6.25%, 1/16), t439 (6.25%, 1/16), and t1928 (6.25%, 1/16). These findings will be useful for future research on anti-virulence therapies and the epidemiology of the strains circulating in our hospital.

Due to the newly emerging Omicron variant, there is a need to re-evaluate the performance of automated antigen tests. Our study aim was to evaluate the performance of the automated Liaison SARS-CoV-2 antigen assay against reverse transcriptase polymerase chain reaction (RT-PCR) in samples with Omicron variant.A prospective study was performed on 373 combined oro-nasopharyngeal samples (NPS) randomly collected from symptomatic patients. NPS were tested with Liaison SARS-CoV-2 Ag test (DiaSorin, Italy) and DS Coronex COVID-19 Multiplex RT-PCR Diagnosis Kit (DS BioTechnology, Ankara, Turkey).Of 373 samples, 124 (33.2%) were found to be RT-PCR positive and 249 (66.8%) RT-PCR negative. Taking RT-PCR as a reference, the sensitivity and specificity of the Liaison SARS-CoV-2 Ag assay were found as 84.6% (95%CI 77.3%-90%) and 100% (95%CI 98.5%-100%), respectively. For samples with a cycle threshold (Ct) value <25 (high viral load), the sensitivity increased to 100%. When antigen concentration and Ct values were compared, a strong negative correlation between antigen and Ct values was determined (P < 0.001).The Liaison antigen test met the performance criteria recommended by the WHO for samples with the Omicron variant. In addition, it showed excellent sensitivity and specificity in patients with high viral load. Therefore, Liaison antigen test can be a reliable and useful alternative in the diagnosis of SARS-CoV-2 infection, particularly in resource-constrained laboratories.

Infections caused by multidrug resistant (MDR) Pseudomonas aeruginosa isolates in burn patients restrict therapeutic strategies. The current study aimed to analyze antibiotic resistance genes and multilocus sequence typing (MLST) of P. aeruginosa strains isolated from burn patients in Shahid Motahari hospital in Tehran, Iran.Altogether 63 P. aeruginosa isolates were characterized in this study. Antibiotic susceptibility testing was performed by disc diffusion method. PCR was performed to determine the frequency of resistance genes. The expression rates of mexB, mexY genes were evaluated by Real-Time PCR. Genotyping of isolates was performed by MLST analysis. All isolates were MDR in this study. The highest resistance was detected against gentamicin, tobramycin, and cefoxitin (100%), while all isolates were susceptible to colistin. Altogether 14 resistance profiles were determined, and profile 1 included more than 50% of the isolates with the highest resistance. In this study blaampC, blaVIM-2, blaOXA-10, and aac(6')-Ib resistance genes were detected in all isolates. The expression levels of mexB and mexY genes were upregulated in 66.6 and 88.8% of MDR isolates, respectively. Overexpression of both genes was detected in 55.5% of the isolates.MLST analysis revealed five sequence types (STs), including ST235, ST664, ST532, ST2637, and ST230, which showed a significant relationship with antibiotic resistance profiles. The present study indicates an increase in antibiotic resistance against different antibiotic families among P. aeruginosa isolates. We describe the circulation of globally distributed STs among hospitalized patients, and we report ST235 as the most common MDR clone in our study.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen causing health care-infections in the world, especially in burns. The aim of this study was to assess the extent of dissemination of MRSA isolated from burn patients in Burn Intensive Care Unit in Tunisia and to evaluate the frequency of virulence and antibiotics resistance genes. Among the 72 S. aureus isolates analyzed in the study, 54% were MRSA. The majority of MRSA (94.8%) were multidrug resistant and they had a high resistance rates to kanamycin (94.8%), tobramycin (90%), tetracycline (94.8%) and ciprofloxacin and rifampicin (87%, each). The gene aac(6')-Ie-aph(2″)-Ia conferring resistance to kanamycine and tobtamycin were detected in all isolates and the aph(3')-Ia gene conferring resistance to gentamicin were detected in 2.8% of resistant isolates. Tetracycline resistance genes tet(M), tet(K) and tet(L) were detected in 100%, 10.8% and 2.8% of the isolates, respectively. The SCCmec type III and the agr type I were the most predominant (69.2% and 90%, respectively). The 27 SCCmecIII-agrI isolates were clustered into two PFGE types A and B. The two representative isolates of PFGE clusters A and B belonged to ST239-t037 and ST241-t037 respectively. As conclusion, our results showed a high prevalence of MRSA in trauma burn intensive care unit belonging to two multidrug resistant clones ST239/ST241-agrI-t037-SCCmecIII MRSA. We also demonstrated that MRSA was disseminated between burn patients.

The aim of this study was to determine the frequency of carbapenem resistant Klebsiella pneumoniae (CRKP) sequence types (STs) in Iran. Samples were collected from three university hospitals in Sanandaj, Iran, from December 2016 to March 2018. Antibiotic susceptibility testing, phenotypic and genotypic detection of carbapenemases were performed. Common K. pneumoniae capsular types were sought for all isolates. The genetic relatedness of isolates was investigated by multilocus sequence typing (MLST). Plasmids were detected by PCR-based Replicon Typing (PBRT). During the study, 67 K. pneumoniae isolates were identified. Of which, 18 (26.9%) isolates were detected as carbapenem-resistant. The most effective antibacterial agent was tigecycline (97%, 65 isolates) followed by imipenem and ertapenem (73.13%, 49 isolates). PCR showed that 13 isolates (19.4%) had blaNDM-1 gene and 5 (7.5%) harbored blaOXA-48. Examination of common capsular types showed that 2 isolates had K2 and 2 others had K54. REP-PCR revealed 10 clones and 11 singleton strains. MLST analysis of CRKP found ST15 as the most common type (13 isolates, 72.2%), but other STs were also detected namely, ST19, ST117, ST1390, and ST1594. ColE1 and IncL/M plasmids were the carriers of blaNDM-1 and blaOXA-48, respectively. The results showed that CRKP spread in our health centers. Our results, therefore, indicate a worrying trend of resistance to carbapenems in K. pneumoniae.

Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading pathogen in urinary tract infection. In recent years multidrug-resistant B2-ST131 E. coli clonal group has disseminated worldwide. The ST131 and its subclones H30 and H30-Rx have been identified only in a few studies from Turkey. The aim of this study is to investigate the presence of ST131 and its subclones and to analyze their adhesin virulence genes and antimicrobial resistance. A total of 250 urinary ExPEC isolates were included in the study. Resistance rates of 16 antimicrobial agents were determined by disk-diffusion. Multidrug-resistance and ESBL production were analyzed. Altogether 8 adhesin genes were investigated namely, papAH, fimH, sfa/focDE, focG, afa/draBC, iha, bmaE and gafD. A total of 39 ST131 isolate were determined and 33 (84.6%) were multidrug-resistant. ESBL production was detected in 34 (87.2%) ST131 and 61 (28.9%) of non-ST131 strains. In our study, we found a strong correlation between ST131 strains and fimH, iha, afa/draBC, papAH virulence determinants. Twenty-nine (85.3%) of 34 ST131-O25b-H30 isolates were identified as H30-Rx. All the papAH gene positive isolates were identified within ST131-O25b-H30-Rx lineage. Non-H30-Rx isolates within H30 isolates were identified as pattern 2. Almost 16% of the isolates were identified as ST131 regardless of clinical syndrome and approximately 34% of the multidrug-resistant isolates were H30-Rx subclone. We report H30-Rx as the dominant subclone of ST131 in our study. Imipenem, fosfomycin and nitrofurantoin proved to be the most effective agents according to antibiotic resistance patterns of both ST131 and non-ST131 E. coli strains.