Acta Microbiologica Et Immunologica Hungarica[JOURNAL]
Sun
200 papers
Antimicrobial resistance of Serratia marcescens causing blood stream infections in a large University Hospital in Bulgaria, an 8-year analysis (2016-2023).
Radeva S, Niyazi D, Bozhkova M … +1 more , Stoeva T
Acta Microbiol Immunol Hung · 2024 Sep · PMID 39088273 · Publisher ↗
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, Bul...
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 increases invasion in intestinal epithelial cells by disrupting the cytoskeleton.
Wang X, Yin XH, Yang JL … +4 more , Tu F, Rui XH, Liu J, Xu P
Acta Microbiol Immunol Hung · 2024 Sep · PMID 39078704 · Publisher ↗
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. pneumo...
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.
Association of antibiotic resistance and biofilm formation in Escherichia coli ST131/O25b.
Aydın E, Kocaaga M, Temel A
Acta Microbiol Immunol Hung · 2024 Sep · PMID 39037809 · Publisher ↗
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 biofil...
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.
16S rRNA based metagenomic analysis unveils unique oral microbial signatures in oral squamous cell carcinoma cases from Coastal Karnataka, India.
Aparna KG, Ravindra J, Chakraborty G … +3 more , Ballamoole KK, Vinaya Kumar JR, Chakraborty A
Acta Microbiol Immunol Hung · 2024 Sep · PMID 38949882 · Publisher ↗
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 dise...
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.
Comparative evaluation of culture results and composition of microbiome of removed tonsils due to distant focal disease or other reasons. A prospective pilot study.
Bella Z, Erdélyi E, Kiricsi Á … +6 more , Gaál V, Lázár A, Maróti G, Wirth R, Sóki J, Nagy E
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38941152 · Publisher ↗
The aim of this prospective pilot study was to compare culture and microbiome results of the removed tonsils of patients with assumed distant focal disease (11 patients) and those who underwent a tonsillectomy, due to ot...
The aim of this prospective pilot study was to compare culture and microbiome results of the removed tonsils of patients with assumed distant focal disease (11 patients) and those who underwent a tonsillectomy, due to other reasons, such as recurrent tonsillitis, tonsil stones or snoring (nine patients). Aerobic culture was carried out for samples taken from the surface of the tonsils by swabs before tonsillectomy for all 20 patients. The squeezed detritus and the tissue samples of removed tonsils, taken separately for the right and left tonsils, were incubated aerobically and anaerobically. The microbiome composition of tissue samples of removed tonsils was also evaluated. Based on the culture results of the deep samples Staphylococcus aureus was the dominating pathogen, besides a great variety of anaerobic and facultative anaerobic bacteria present in the oral microbiota in those patients who underwent tonsillectomy due to distant focal diseases. Microbiome study of the core tissue samples showed a great diversity on genus and species level among patients of the two groups however, S. aureus and Prevotella nigrescens were present in higher proportion in those, whose tonsils were removed due to distant focal diseases. Our results may support previous findings about the possible triggering role of S. aureus and P. nigrescens leading to distant focal diseases. Samples taken by squeezing the tonsils could give more information about the possible pathogenic/triggering bacteria than the surface samples cultured only aerobically.
Evaluation of biofilm formation and expression of psl, pel, alg genes of Pseudomonas aeruginosa in exposure to detergents.
Al-Enazi NM
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38869956 · Publisher ↗
Pseudomonas aeruginosa has been in the center of attention for several years as an opportunistic human pathogen implicated in many severe acute and chronic infections particularly in immunocompromised patients. Its high...
Pseudomonas aeruginosa has been in the center of attention for several years as an opportunistic human pathogen implicated in many severe acute and chronic infections particularly in immunocompromised patients. Its high persistence and resistance against many antimicrobial agents are mostly attributed to biofilm formation. Biofilms are microbial communities mainly consisting of extracellular polymeric substances that encapsulate bacteria together and protect them from extracellular stresses. This cell aggregation is a stress response that P. aeruginosa employes as a survival strategy during growth with the toxic detergents. This process has shown to involve several operons such as psl, pel, and alg. Here we used P. aeruginosa strain PAO1 in control group, 40 P. aeruginosa strains from sink and 40 strains from surface of public places. Biofilm formation and gene expression were measured before and after exposure to sub minimum inhibitory concentration (sub-MIC) of biocides chlorhexidine diacetate and benzalkonium chloride. The qRT-PCR and biofilm formation results demonstrated an increase in biofilm formation ability and gene expression of pslA/B and pelA/B in two groups collected from sink and surface in contrast to the control group. A remarkable increase was observed in the biofilm formation and expression of pslA in the bacterial strain collected from the sink after exposure to biocides chlorhexidine diacetate. Both Pel and Psl appeared to have redundant functions as structural scaffolds in biofilms. Sub-MIC levels of detergents can improve biofilm formation ability of P. aeruginosa and therefore trigger resistance.
Genomic insights into NDM-1-producing Pseudomonas aeruginosa: Current status in a Bulgarian tertiary hospital and on the Balkans.
Strateva T, Keuleyan E, Peykov S
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38857113 · Publisher ↗
The present study aimed to explore the genomic characteristics of eight New Delhi metallo-β-lactamase-1 (NDM-1)-producing carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates from a Bulgarian tertiary hospital (20...
The present study aimed to explore the genomic characteristics of eight New Delhi metallo-β-lactamase-1 (NDM-1)-producing carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates from a Bulgarian tertiary hospital (2021-2023) in comparison to blaNDM-1-positive strains originating from the Balkans. Antimicrobial susceptibility testing, phenotypic assays for carbapenemase activity, PCR screening, whole-genome sequencing (WGS), and phylogenomic analysis were performed. Seven of the CRPA isolates investigated (Minimum inhibitory concentration values of imipenem and meropenem >32 mg L-1) were also resistant to piperacillin-tazobactam, ceftazidime, ceftazidime-avibactam, cefepime, ceftolozane-tazobactam, amikacin, tobramycin, ciprofloxacin, and levofloxacin, but were susceptible to colistin (0.5-2 mg L-1) and cefiderocol (0.25-1 mg L-1). The P. aeruginosa Pae57 isolate (designated Pae57) remained susceptible to aminoglycosides as well. WGS uncovered the co-existence of blaNDM-1 and blaGES-1. The isolates belonged to the ST654 high-risk clone, except for Pae57 (ST611). Alignment against reference sequences revealed the presence of a Tn21 transposon harboring bleMBL-blaNDM-1-ISAba125. It was similar to that found in the P. aeruginosa ST654 NDM1_1 strain (GCA_020404785.1) from Serbia. Phylogenomic analysis of our isolates indicated that seven of them (ST654) differed from each other in no more than 44 single-nucleotide polymorphisms (SNPs). Pae57 (ST611) was strikingly different (>21,700 SNPs) compared to all Balkan strains. In conclusion, to our knowledge this is the first report of blaNDM-1-positive P. aeruginosa ST611 isolation, which indicates the transmission dynamics of this determinant between high-risk and potentially high-risk P. aeruginosa clones. Obtained results unveil the dissemination of clonally related NDM-1-producing P. aeruginosa strains in the monitored hospital for approximately a 2-year period.
Genetic alterations in the pmrAB two-component system and lipid A biosynthesis genes of polymyxin-resistant Acinetobacter baumannii isolates.
El Mrimar N, Belouad EM, Benaissa E … +5 more , Bssaibis F, Jazouli M, El Alaoui MA, Maleb A, Elouennass M
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38837239 · Publisher ↗
The rate of pandrug-resistant Acinetobacter baumannii strains is on the rise in all continents. This bacterium can acquire resistance to all antibiotics, even to colistin. Alterations in the lipid A or/and the two-compon...
The rate of pandrug-resistant Acinetobacter baumannii strains is on the rise in all continents. This bacterium can acquire resistance to all antibiotics, even to colistin. Alterations in the lipid A or/and the two-component pmrAB were earlier detected in colistin resistance. We investigated and analyzed two strains of A. baumannii (ABRC1 and ABRC2) isolated from two patients admitted to intensive care unit with a septic shock. Both strains were resistant to all tested antibiotics including colistin with a MIC >256 mg L-1. Colistin resistance genes (pmrA, pmrB, lpxA, lpxC, lpxD, and lpsB) of two strains (ABRC1 and ABRC2) were investigated by PCR and sequencing. Obtained nucleic acid sequences were aligned with reference sequences of ATCC 19606 and 17987. In this study two amino acid mutations, N287D in the lpxC gene and E117K in the lpxD gene, were detected in both ABRC1 and ABRC2 strains. ABRC1 had an additional H200L mutation in the pmrA gene. Both colistin resistant strains harbored the same A138T mutation in the pmrB gene. The ABRC2 strain also had an alteration in the kinase domain, specifically an R263S substitution of the histidine kinase domain. Three identical mutations were found in the lpsB gene of both A. baumannii strains: Q216K + H218G + S219E. As a result, a newly deduced protein sequence in both ABRC1 and ABRC2 strains differed from those described in ATCC 17978 and 19606 strains was determined. Colistin resistance is multifactorial in A. baumannii. In our study we detected novel mutations in colistin resistant A. baumannii clinical isolates.
Efficacy of ceftazidime/avibactam and plazomicin on carbapenem-resistant Klebsiella pneumoniae and Escherichia coli.
Öztaş S, Er DK, Dündar D … +1 more , Keçeli SA
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38837219 · Publisher ↗
Carbapenem-resistant Enterobacterales (CRE) have become a major public health problem worldwide. The aim of this study was to investigate efficacy of ceftazidime/avibactam and plazomicin on carbapenem-resistant Klebsiell...
Carbapenem-resistant Enterobacterales (CRE) have become a major public health problem worldwide. The aim of this study was to investigate efficacy of ceftazidime/avibactam and plazomicin on carbapenem-resistant Klebsiella pneumoniae and Escherichia coli isolates. Susceptibility of imipenem, meropenem, ertapenem, ceftazidime/avibactam and plazomicin was investigated by broth-microdilution method. Major carbapenemases NDM, VIM, IMP, KPC, OXA-48 as well as other β-lactamases namely, TEM, SHV, OXA-1-like, CTX-M, ACC, FOX, MOX, DHA, CIT, EBC, VEB, GES, PER were investigated by PCR. A total of 120 carbapenem-resistant isolates (60 E. coli and 60 K. pneumoniae) were included in this study and blaOXA-48-like was found in 78.33%, blaNDM in 26.66%, blaKPC in 7.5%, blaIMP in 5.83%, and blaVIM in 5%. Among 94 isolates with the blaOXA-48-like gene, 22.3% were resistant to ceftazidime/avibactam and 51.1% were resistant to plazomicin. Of 32 isolates with blaNDM, 31 (96.9%) were resistant to ceftazidime/avibactam and 30 (93.75%) were resistant to plazomicin, and both antibiotics had limited effects against blaNDM carriers (P < 0.001). Of the 12 isolates with blaNDM+OXA-48 combination, 11 (91.7%) were resistant to ceftazidime/avibactam and plazomicin. The effect of both antibiotics was significantly lower in strains with blaNDM+OXA-48 combination (P < 0.005).The most common carbapenemase genes in this study were blaOXA-48-like and blaNDM. Ceftazidime/avibactam demonstrated a good efficacy among OXA-48 producing K. pneumoniae and E. coli, however, plazomicin had a significantly lower antibacterial effect in our study. Both antimicrobial agents should be considered as an option by evaluating combined susceptibility results and gene patterns obtained by regional and global molecular data in the treatment of CRE infections.
Antimicrobial resistance trends among Klebsiella pneumoniae associated with urinary tract infections in Crete, Greece, 2017-2022.
Maraki S, Mavromanolaki VE, Stafylaki D … +2 more , Iliaki-Giannakoudaki E, Kasimati A
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38776141 · Publisher ↗
Klebsiella pneumoniae is one of the most prevalent bacteria causing urinary tract infections (UTIs). Its increasing resistance to a wide array of antibiotics limits available treatment options. This study investigated th...
Klebsiella pneumoniae is one of the most prevalent bacteria causing urinary tract infections (UTIs). Its increasing resistance to a wide array of antibiotics limits available treatment options. This study investigated the characteristics and trends of antimicrobial resistance in K. pneumoniae isolated from UTIs in Crete, Greece, during 2017 and 2022. Among the 11,946 Enterobacteriaceae isolated from urine specimens, a total of 1,771 K. pneumoniae isolates were identified (14.8%), with an isolation frequency secondary to Escherichia coli (66.3%). K. pneumoniae isolates increased over the years, with a peak in the year 2022. Higher resistance rates were detected in ciprofloxacin (41%), trimethoprim/sulfamethoxazole (TMP/SMX) (38.1%) and nitrofurantoin (33.9%). Resistance to ciprofloxacin, amoxicillin/clavulanic acid, tigecycline, and TMP/SMX significantly increased from 33.7%, 24%, 6%, and 33.1%, respectively, over the years 2017-2019, to 47.8%, 34.2%, 14.3% and 42.8%, respectively, over the period 2020-2022. ESBL production and carbapenem resistance were decreased by 2.2% and 3.7%, respectively, over the two three-year periods (2017-2019 and 2020-2022). Among the 278 carbapenem-resistant K. pneumoniae (CRKP) isolates, 164 (59%), 66 (23.7%), 18 (6.5%) and 16 (5.8%) were positive for KPC, NDM, VIM and OXA-48 enzymes, respectively. Only 14 (5%) isolates harboured two carbapenemase genes, namely 10 (3.6%) both blaNDM and blaVIM, and 4 (1.4%) both blaKPC and blaNDM. Females, inpatients and the elderly were more frequently affected by CRKP. The frequency of multidrug-resistant (MDR) and extensively drug-resistant (XDR) isolates were 32.6% and 7.7%, respectively. Continuous surveillance of local microbial prevalence and monitoring of antimicrobial resistance patterns provide critical information to guide the empiric therapy for UTIs and control the spread of MDR bacteria.
Epidemiological and bacterial profile of childhood meningitis in Tunisia.
Dhraief S, Meftah K, Mhimdi S … +9 more , Khiari H, Aloui F, Borgi A, Haddad-Boubaker S, Brik A, Menif K, Kechrid A, Bouafsoun A, Smaoui H
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38771654 · Publisher ↗
The worldwide burden of disease of bacterial meningitis remains high, despite the decreasing incidence following introduction of routine vaccination campaigns.The aim of our study was to evaluate the epidemiological and...
The worldwide burden of disease of bacterial meningitis remains high, despite the decreasing incidence following introduction of routine vaccination campaigns.The aim of our study was to evaluate the epidemiological and bacteriological profile of paediatric bacterial meningitis (BM) in Tunisian children, during the period 2003-2019, following the implementation of Haemophilus influenzae type b (Hib) vaccine (April 2011) and before 10-valent pneumoccocal conjugate vaccine (PCV10) introduction to the childhood immunization program.All bacteriologically confirmed cases of BM admitted to children's hospital of Tunis were recorded (January 2003 to April 2019). Serogroups of Neisseria meningitidis (Nm) and serotypes of Streptococcus pneumoniae (Sp) and H. influenzae (Hi) and antibiotic resistance were determined using conventional and molecular methods.Among 388 cases, the most frequent species were Sp (51.3%), followed by Nm (27.5%) and Hi (16.8%). We observed a significant decrease in Hi BM rate during the conjugated Hib vaccine use period (P < 0.0001). The main pneumococcal serotypes were 14, 19F, 6B, 23F and 19A and the serotype coverage of PCV10, PCV13, PCV15 and PCV20 was 71.3 and 78.8%, 79.4 and 81.9% respectively. The most frequent Nm serogroup was B (83.1%). Most Hi strains were of serotype b (86.9%). High levels of resistance were found: Sp and Nm to penicillin (respectively 60.1 and 80%) and Hi to ampicillin (42.6%). All meningococcal and Hi isolates were susceptible to third-generation cephalosporins and 7.2% of pneumococcal strains had decreased susceptibility to these antibiotics.The Hib conjugate vaccine decreased the rate of BM. Sp dominated the aetiology of BM in children in Tunisia. Conjugate vaccines introducing decreases not only BM cases but also antimicrobial resistance.
Unveiling the emergence of SARS-CoV-2 JN.1 sub-variant: Insights from the first cases at Charles Nicolle Hospital, Tunisia.
Hamzaoui Z, Ferjani S, Kanzari L … +13 more , Ben Ali R, Charaa L, Landolsi I, Medini I, Chammam S, Abid S, Ferjani A, Kebaier D, Fakhfakh A, Bouslah Z, Ben Sassi M, Trabelsi S, Boutiba-Ben Boubaker I
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38717854 · Publisher ↗
The JN.1 sub-variant is a new variant of the SARS-CoV-2 Omicron strain, derived from the BA.2.86 sub-variant. It was first detected in late 2023 and has quickly spread to many countries, becoming the most prevalent varia...
The JN.1 sub-variant is a new variant of the SARS-CoV-2 Omicron strain, derived from the BA.2.86 sub-variant. It was first detected in late 2023 and has quickly spread to many countries, becoming the most prevalent variant in some regions. JN.1 exhibits a unique mutation (L455S) in the spike protein compared to the BA.2.86 lineage, which may affect its transmissibility and immune evasion capabilities. JN.1 has been designated as a "variant of interest" by the World Health Organization due to its rapidly increasing spread and is being closely monitored for its impact on the COVID-19 pandemic. This study describes the emergence of SARS-CoV-2 JN.1 sub-variant in Tunisia, and reports its mutation profiles.Nasopharyngeal samples collected over a four-month period (October 2023 to January 2024) were subjected to RNA extraction and real-time RT-PCR confirmation of SARS-CoV-2 infection. The whole-genome sequencing was performed by an iSeq 100 sequencer and COVIDSeq kit reagents (Illumina, USA).Mutation analysis, using the NextClade platform and GISAID database, revealed the presence of JN.1 in 15 out of 80 positive cases (18.75%) during the study period.The emergence of JN.1 highlights the ongoing evolution of SARS-CoV-2 and the need for continued surveillance and research to better understand the characteristics and impact of emerging variants.
16S rRNA sequencing reveals microbiota differences in orthopedic implants between aseptic loosening and prosthetic joint infection cases.
Cetiner OF, Hora M, Kafadar IH … +2 more , Ulu Kilic A, Gundogdu A
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38619882 · Publisher ↗
Prosthetic joint infection (PJI) and aseptic loosening (AL) are common complications of total joint arthroplasty. An accumulation of evidence indicates the presence of microbial communities on prosthetic implants, but th...
Prosthetic joint infection (PJI) and aseptic loosening (AL) are common complications of total joint arthroplasty. An accumulation of evidence indicates the presence of microbial communities on prosthetic implants, but the overall microbial profile is unclear. In this study, we aimed to investigate the differences in the microbial composition of prosthetic implants obtained from PJI and AL patients using the 16S rRNA sequencing method. Patients who underwent revision hip, knee, or shoulder arthroplasty caused by PJI (n = 20) or AL (n = 10) were enrolled in the study. 16S rRNA sequencing targeting the V3-V4 region was performed on the microbial specimens collected from synovial fluid, periprosthetic deep-tissue, and biofilm during the revision surgery. The sequenced raw data were analysed for microbial composition and ecological and differential abundance analyses using bioinformatics tools. The AL group had relatively balanced and higher diversity, with Staphylococcus, Streptococcus, and Veillonella being prominent. In the PJI group, Staphylococcus and Pseudomonas were predominant, especially in deep-tissue samples and biofilm samples, respectively. The differential abundance analysis identified 15 and 2 distinctive taxa in the AL and PJI groups, respectively. Our findings provided preliminary insights supporting the existence of periprosthetic microbiota in orthopedic implants and explaining the differences in microbial composition between the AL and PJI groups.
Prevalence and genetic characteristics of Staphylococcus aureus isolates from cell phones of medical students from Iran.
Behrouzmanesh F, Samali SA, Nasehi R … +2 more , Shivaee A, Goudarzi M
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38619878 · Publisher ↗
Although mobile phones as a rapid communication vehicle can lead to improved quality of healthcare, they can also facilitate the transmission of pathogens to patients. This current research focuses on genetic diversity,...
Although mobile phones as a rapid communication vehicle can lead to improved quality of healthcare, they can also facilitate the transmission of pathogens to patients. This current research focuses on genetic diversity, and genes involved in resistance and biofilm production of Staphylococcus aureus isolates from mobile phones of medical students. Antibiotic resistance profiling and polymerase chain reaction (PCR) amplification of antibiotic resistance and biofilm-related genes were investigated and statistically analyzed. Staphylococcal cassette chromosome mec (SCCmec) types were analyzed by multiplex PCR, and S. aureus protein A gene typing (spa typing) was done using PCR and sequencing. Sixty-four S. aureus isolates (16.8%) were obtained from 380 medical students' mobile phones who were working in hospitals. The findings showed that 71.9% of the isolates were MRSA and 78.1% were classified as MDR. All isolates exhibited sensitivity to vancomycin and linezolid. Overall, 7.8% of the isolates displayed an inducible clindamycin resistance phenotype, while 26.7% showed resistance to mupirocin. The results indicated that 68.8% of the isolates were biofilm producers, with 7 isolates (15.9%) classified as strong producers, 22 isolates (50%) as moderate producers, and 15 isolates (34.1%) as weak producers. The most prevalent type was CC8-MRSA III/t030 (18.7%), followed by CC8-MRSA III/t037 (12.5%), CC/ST22-MSSA/t790 (10.9%), CC1-MRSA IV-t114 (9.4%), CC1-MRSA IV-t127 (7.8%), CC8-MRSA V/t064 (7.8%), CC/ST15-MSSA-t360 (7.8%), CC30-MSSA/t021(6.3%), MRSA V-t355 (6.3%), CC8-MRSA III/t421 (4.7%), CC1-MRSA V-t267 (4.7%), and CC/ST15-MSSA-t084 (3.1%). The genetic diversity and prevalent multidrug resistance indicate that the resistance situation of S. aureus recovered from mobile phones in Tehran is severe, posing a potential threat to patients, the community, and healthcare settings.
Rapid detection of carbapenemase-producing gram-negative bacteria directly from blood culture bottles for a reliable guided empiric therapy.
Rezk S, Ashraf N, Heshmat H … +2 more , Elsawaf G, Elsheredy A
Acta Microbiol Immunol Hung · 2024 Jul · PMID 38573768 · Publisher ↗
Bloodstream infections (BSIs) caused by multidrug-resistant bacteria are a critical life-threatening challenge which necessitates the urgency to trigger life-saving treatment in a timely manner. This study aimed to evalu...
Bloodstream infections (BSIs) caused by multidrug-resistant bacteria are a critical life-threatening challenge which necessitates the urgency to trigger life-saving treatment in a timely manner. This study aimed to evaluate the time required for rapid detection of carbapenemase-producing Enterobacterales (CPE) directly from blood culture bottles to optimize empirical treatment of BSI, especially in pediatric and infant patients, using a cost-effective method. This study included 419 Gram-negative bacteria, of which Klebsiella pneumoniae and Escherichia coli were the most common CPE causing BSI in pediatric and neonatal patients. Phenotypic and genotypic resistance of the selected isolates (45 K. pneumoniae and 9 E. coli) were determined by VITEK-2 Compact system and PCR, respectively. BACT/ALERT bottles were spiked with isolates. Finally, colorimetric RESIST-BC assay and Vitek-2 compact system were evaluated for the rapid detection of carbapenem-resistant bacteria directly from positive blood culture bottles. All selected isolates were phenotypically resistant to carbapenems. PCR showed that blaNDM and blaOXA-48 were present in all isolates, blaVIM was present in 44.4%, while blaKPC and blaIMP were entirely absent. The RESIST-BC kit showed good agreement with PCR for blaNDM and blaOXA-48, demonstrating high sensitivity and specificity, but not with blaVIM. These findings point out that RESIST-BC assay demonstrated an exceptionally short detection time for CPE, completing all cases within the first hour after the blood culture bottles flagged positive. It is also superior in providing a clue for clinicians on antibiotic combinations that can be administered, depending on the type of β-lactamases detected, promptly and efficiently, with low expenses.
Phylogenetic analysis and antimony resistance of Leishmania major isolated from humans and rodents.
Moghaddam Y, Ziaei Hezarjaribi H, Pagheh AS … +6 more , Fakhar M, Saberi R, Sharbatkhori M, Montazeri M, Ghalehnoei H, Nazar E
Acta Microbiol Immunol Hung · 2024 Mar · PMID 38520480 · Publisher ↗
Cutaneous Leishmaniasis (CL) is one of the world's neglected diseases which is caused by Leishmania spp. The aim of this study was to assess molecular profile and antimony resistance of Leishmania isolated from human and...
Cutaneous Leishmaniasis (CL) is one of the world's neglected diseases which is caused by Leishmania spp. The aim of this study was to assess molecular profile and antimony resistance of Leishmania isolated from human and rodent hosts. Samples were collected from suspected CL patients referred to health centres and wild rodent's traps in Gonbad-e-Qabus region, north-eastern Iran. Smears were subjected to PCR-RFLP to identify Leishmania species. In addition, ITS1-PCR products were sequenced for phylogenetic analysis. Clinical isolates and rodent samples were subjected to MTT assay to determine IC50 values and in vitro susceptibilities. Expression levels of antimony resistance-related genes were determined in CL isolates. Out of 1,949 suspected patients with CL and 148 rodents, 1,704 (87.4%) and 6 (4.05%) were positive with direct smear, respectively. Digestion patterns of BusRI (HaeIII) endonuclease enzyme were similar to what expected for Leishmania major. Phylogenetic analysis revealed that the highest interspecies similarity was found between current L. major sequences with L. major obtained from Russia and Uzbekistan. Out of 20 L. major samples tested, 13 (65%) were resistant to meglumine antimoniate (MA) treatment, with an activity index (AI) exceeding 4. The remaining 7 samples (35%) responded to MA treatment and were classified as sensitive isolates, with a confirmed sensitive phenotype based on their AI values. The comparison expression analysis of three major antimony resistance-associated genes in unresponsive clinical isolates demonstrated significant fold changes for TDR1 (4.78-fold), AQP1 (1.3-fold), and γ-GCS (1.17-fold) genes (P < 0.05). Herein, we demonstrate genetic diversity and antimony resistance of L. major isolated from human and reservoir hosts in north-eastern Iran, which could be the basis for planning future control strategies.
Occupational exposure to Coxiella burnetii during cardiac surgery: A case report and review of the literature.
Diwunga P, Million M, Ravaux I … +2 more , Fournier PE, Gautret P
Acta Microbiol Immunol Hung · 2024 Mar · PMID 38466372 · Publisher ↗
We report a case of exposure to Coxiella burnetii in a surgical nurse who underwent an injury of her finger with a scalpel blade during a native aortic valve replacement with a bio-prosthetic cardiac valve conducted on a...
We report a case of exposure to Coxiella burnetii in a surgical nurse who underwent an injury of her finger with a scalpel blade during a native aortic valve replacement with a bio-prosthetic cardiac valve conducted on a patient suffering from C. burnetii aortic endocarditis. Given the positivity of C. burnetii culture and PCR from the patient's aortic valve, she was prescribed prophylactic doxycycline 100 mg twice a day for 10 days. Q fever is an occupational zoonosis resulting usually of exposure to infected animals by inhalation of infected aerosols or consumption of contaminated raw milk. Apart from materno-foetal transmission, about 180 cases of human-to-human C. burnetii transmission have been published from 1949 to today, including transmission by blood transfusion, sexual relations, transmission in the healthcare setting to staff, patient attendants and other patients that were likely infected from inhalation of aerosol from respiratory or placental products, transmission to staff during autopsies of patients with Q fever and transmission in familial settings. As C. burnetii is a highly infectious bacterium, that may cause infection with a low inoculum, it should be added to the list of organisms which may be of concern following blood exposure among healthcare professionals.
KPC-2 and VIM-1 producing Klebsiella pneumoniae ST39 high-risk clone isolated from a clinical sample in Volos, Greece.
Chatzidimitriou M, Tsolakidou P, Panagiota C … +2 more , Mylona E, Mitka S
Acta Microbiol Immunol Hung · 2024 Mar · PMID 38451279 · Publisher ↗
Klebsiella pneumoniae is a major human pathogen, because it causes both community- and hospital-acquired infections. Several multidrug-resistant high-risk clones of K. pneumoniae have been reported worldwide, and these a...
Klebsiella pneumoniae is a major human pathogen, because it causes both community- and hospital-acquired infections. Several multidrug-resistant high-risk clones of K. pneumoniae have been reported worldwide, and these are responsible for high numbers of difficult-to-treat infections. In Greece, a K. pneumoniae ST39 high-risk clone was detected in 2019 in a survey of carbapenem- and/or colistin-resistant Enterobacteriacae. The present study included nine carbapenem-resistant K. pneumoniae (CRKP) isolates collected during a retrospective analysis from October 2020 to December 2020. They were isolated from nine different patients hospitalized in the intensive care unit (ICU) of a hospital in Volos, Greece, and they were selected for analysis due to their phenotypic profile. In this study, we analyzed A165 strain K. pneumoniae ST39 isolated from a blood culture in November 2020. Whole-genome sequencing (WGS) was performed using Ion Torrent Platform, and resistance genes, virulence determinants, capsular types, insertion sequences, phage regions, and clustered regularly interspaced palindromic repeats (CRISPR) regions were detected by bioinformatic analysis. The molecular characterization revealed antimicrobial resistance genes, including sul2 for sulfamethoxazole; dfrA1 for trimethoprim; blaVIM-1 and blaKPC-2 for carbapenems; aac(6')-II for aminoglycosides; fosA for fosfomycin and aad1 for streptomycin, blaSHV-40, blaSHV-85, blaSHV-79, blaSHV-56, and blaSHV-89 for beta-lactams. Point mutations were identified in ompK36, and ompK37 and in acrR, gyrA, parC. Several replicons were found, including CoIRNA, IncC, IncFIB(K), IncFIB(pQiL), and IncFII(K). The capsular typing revealed that the strain was KL23, O2afg. The genome sequence of A165 was submitted to NCBI under PRJNA1074377 and have been assigned to Genbank accession number JAZIBV000000000.
Carbapenem-resistant Klebsiella pneumoniae in the Balkans: Clonal distribution and associated resistance determinants.
Chatzidimitriou M, Kavvada A, Kavvadas D … +5 more , Kyriazidi MA, Eleftheriadis K, Varlamis S, Papaliagkas V, Mitka S
Acta Microbiol Immunol Hung · 2024 Mar · PMID 38381174 · Publisher ↗
Carbapenems are considered to be among the last line antibiotics against extended-spectrum β-lactamase producing Enterobacterales. Carbapenem-resistant Klebsiella pneumoniae (CRKP) has been frequently reported and its sp...
Carbapenems are considered to be among the last line antibiotics against extended-spectrum β-lactamase producing Enterobacterales. Carbapenem-resistant Klebsiella pneumoniae (CRKP) has been frequently reported and its spread in Europe is indisputable and poses an enormous threat to hospitalized patients which is of growing concern. This review aims to record prevalence of CRKP in the Balkan region and to review the current knowledge about this life-threatening pathogen. In this review, we summarize data about clinical isolates of carbapenem-resistant K. pneumoniae from Greece, Croatia, Romania, Bulgaria, Serbia, Slovenia, Montenegro, Bosnia-Herzegovina and Albania from published reports between 2000 and 2023. Among Balkan countries, Greece and Romania are the ones with the most reports about CRKP. Since 2007, KPCs are the dominant carbapenemases in both countries. KPC-2 and NDM-1-producing K. pneumoniae strains have been identified as the most frequent CRKP in Croatia, Bulgaria, Serbia, and Slovenia. OXA-48 enzyme has been identified in most Balkan countries. In addition, since 2018, CRKP sequence type 11 (ST11) seems to have replaced ST258 in Balkan Peninsula, while ST15 continues to thrive throughout the years. Not only efficacy of colistin against CRKP has decreased dramatically during the last ten years but colistin resistance mechanism is based on alterations of chromosomal mgrB gene, rather than the already known mcr genes.Moreover, ceftazidime-avibactam-resistant CRKP were detected mostly in Greece. Emergence of CRKP poses a severe threat to the Balkan countries. Due to the narrow therapeutic window, it is essential to prevent the spread of multiresistant K. pneumoniae strains.
High rates of intestinal colonization with carbapenemase producing Enterobacteriaceae in hematopoietic stem cell transplant recipients.
Ayari I, Chebbi Y, Raddaoui A … +6 more , Belloumi D, Frigui S, Werhni R, Ben Othmen T, Abedejlil N, Achour W
Acta Microbiol Immunol Hung · 2024 Mar · PMID 38381147 · Publisher ↗
Carbapenem resistant Enterobacteriaceae (CRE) are major human pathogens because, these cause high number of difficult-to-treat infections. Allogeneic hematopoietic stem cell transplant (AHSCT) recipients are highly expos...
Carbapenem resistant Enterobacteriaceae (CRE) are major human pathogens because, these cause high number of difficult-to-treat infections. Allogeneic hematopoietic stem cell transplant (AHSCT) recipients are highly exposed to these type of bacteria. The aim of our study was to investigate prevalence of CRE colonization in AHSCT patients and to determine genes encoding carbapenem resistance. A retrospective study conducted between January 2015 and December 2019, involved 55 patients colonized with CRE strains. We determined the rate of antibiotic resistance according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the carbapenem resistance genes by PCR assays for genes encoding most frequent β-lactamases namely, blaGES, blaKPC, blaIMI, blaNDM, blaVIM, blaIMP and blaOXA-48. Eighty-one episodes of CRE colonization were recorded in 55 patients, mainly suffering from acute leukaemia (30%) and aplastic anemia (26%). History of hospitalization was noted in 80 episodes. Prior antibiotic treatment, severe neutropenia and corticosteroid therapy were respectively found in 94%, 76% and 58% of cases. Among the 55 patients, six patients (11%) developed a CRE infection. The CRE responsible for colonization were carbapenemase producers in 90% of cases. They belonged mostly to Klebsiella pneumoniae (61/81) and Escherichia coli species (10/81). Antibiotic resistance rates were 100% for ertapenem, 53% for imipenem, 42% for amikacin, 88% for ciprofloxacin and 27% for fosfomycin. Molecular study showed that blaOXA-48 gene was the most frequent (60.5%), followed by blaNDM (58%). Thirty-five (43%) strains were co-producers of carbapenemases. In our study, we report a high rate of CRE intestinal colonization in AHSCT recipients of our center.
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