Major enzymatic factors involved in bacterial penicillin resistance in Burkina Faso. - Related Documents




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169301.0000Major enzymatic factors involved in bacterial penicillin resistance in Burkina Faso. Many clinical species of bacteria were isolated from biological samples such as urines, blood and wound in Saint Camille medical centre of Ouagadougou. Among the concerned species, the most important members were Escherichia coli and Klebsiella pneumoniae. These p-lactamases producing isolates were directly screened by PCR to identify the nature of the amplified genes responsible for penicillin destroying activity. Therefore specific TEM and SHV primers were used. The PCR products were sequenced. The sequencing results indicated that the parental forms bla(TEM-1) and bla(SHV-1) were the most common determinants of beta-lactamase found, respectively in Escherichia species and Klebsiella pneumoniae. The bacterial susceptibility analysis by MICs measurement clearly correlated the presence of concerned beta-lactamase determinants and their resistance patterns. This study is part of a set of investigations carried out by our laboratory to assess the beta-lactamase incidence in the failure of beta-lactam therapy. In particular, the purpose of this study was to determine the precise nature of beta-lactamase supporting the low susceptibility of host bacteria towards penicillins.200719069526
570010.9998Gram-negative bacterial colonization in the gut: Isolation, characterization, and identification of resistance mechanisms. BACKGROUND: The gut microbiome is made up of a diverse range of bacteria, especially gram-negative bacteria, and is crucial for human health and illness. There is a great deal of interest in the dynamic interactions between gram-negative bacteria and their host environment, especially considering antibiotic resistance. This work aims to isolate gram-negative bacteria that exist in the gut, identify their species, and use resistance-associated gene analysis to define their resistance mechanisms. METHODS: Samples were collected from all patients who had a stool culture at a tertiary care center in Lebanon. Each type of bacteria that was identified from the stool samples was subjected to critical evaluations, and all discovered strains underwent antimicrobial susceptibility testing. Polymerase chain reaction was used to profile the genes for Carbapenem-resistant Enterobacteriaceae (CRE), Extended-spectrum beta-lactamase (ESBL), and that of Pseudomonas aeruginosa strains. RESULTS: Escherichia coli, Klebsiella species, and Pseudomonas aeruginosa turned out to be the predominant microbiota members. Escherichia coli strains had a high frequency of extended-spectrum beta-lactamase genes, with the most discovered gene being bla CTX-M. Additionally, a considerable percentage of isolates had carbapenemase-resistant Enterobacteriaceae genes, suggesting the rise of multidrug-resistant strains. Multidrug resistance genes, such as bla mexR, bla mexB, and bla mexA, were found in strains of Pseudomonas aeruginosa, highlighting the possible difficulties in treating infections brought on by these bacteria. CONCLUSION: The findings highlight the critical importance of effective surveillance and response measures to maintain the effectiveness of antibiotics considering the introduction of multidrug resistance genes in Pseudomonas aeruginosa and ESBL and CRE genes in Escherichia coli.202439216133
169620.9998Assessment of the presence of Acinetobacter spp. resistant to β-lactams in commercial ready-to-eat salad samples. Acinetobacter baumannii is a well-known nosocomial infection causing agent. However, other Acinetobacter spp. have also been implicated in cases of human infection. Additionally, these bacteria are known for the development of antibiotic resistance thus making the treatment of the infections they cause, challenging. Due to their relevance in clinical setups less attention has been paid to their presence in foods, and its relation with infection/dissemination routes. In the current study commercial Ready-To-Eat (RTE) salads were analyzed seeking for antibiotic resistant Acinetobacter spp. A preliminary screening allowed us to recover Gram-negative bacteria resistant to β - lactams using cefotaxime, third generation cephalosporins, as the selective agent, and this was followed by identification with CHROMagar™ Acinetobacter and 16S rDNA sequencing. Finally, the isolates identified as Acinetobacter spp. were reanalyzed by PCR to determine the presence of nine potential Extended Spectrum β Lactamases (ESBL). Two commercial RTE salad brands were included in the study (2 batches per brand and 8 samples of each batch making a total of 32 independent samples), and compared against an organic lettuce. High concentrations of β - lactam, resistant bacteria were found in all the samples tested (5 log CFU/g). Additionally, 209 isolates were phenotypically characterized on CHROMagar Acinetobacter. Finally, PCR analysis identified the presence of different ESBL genes, being positive for blaACC, blaSHV, blaDHA and blaVEB; out of these, blaACC was the most prevalent. None of the isolates screened were positive for more than one gene. To conclude, it is important to highlight the fact that pathogenic species within the genus Acinetobacter spp., other than A. baumannii, have been identified bearing resistance genes not typically associated to these microorganisms highlight the importance of continuous surveillance.202438049272
204030.9998Multidrug-resistant bacteria as intestinal colonizers and evolution of intestinal colonization in healthy university students in Portugal. Multidrug-resistant bacteria have been increasingly described in healthcare institutions, however community resistance also seems to be emerging. Escherichia coli an intestinal commensal bacteria, is also a pathogen and represents an important intestinal reservoir of resistance. Our aim was the study of the intestinal colonization and of the persistence of antibiotic resistant intestinal bacteria in healthy university students of Porto, in the north of Portugal. Samples from 30 university students were collected and analysed. Two E. coli isolates were randomly obtained from each student and Gram-negative bacilli resistant to antibiotics were studied. In addition, we evaluated changes in the Gram-negative intestinal colonization of ten university students in a short period of time. Molecular characterization showed a high presence of bla (TEM) in commensal E. coli . Gram-negative bacteria with intrinsic and extrinsic resistance were isolated, namely Pseudomonas spp., Enterobacter spp. and Pantoea spp. We isolated three ESBL-producing E. coli from two students. These isolates showed bla (CTX-M) group 1 (n=1), bla (CTX-M) group 9 (n=2), bla (TEM) (n=2), bla (SHV) (n=1) and tetA (n=2) genes. Additionally, they showed specific virulence factors and conjugational transfer of antibiotic resistance and virulence genes. One Pseudomonas spp. isolate resistant to carbapenems was detected colonizing one student. Our results confirm that healthy young adults may be colonized with commensals showing clinically relevant antibiotic resistance mechanisms, creating a risk of silent spread of these bacteria in the community.202133997613
169240.9998Phenotypic and genotypic detection of antibiotic-resistant bacteria in fresh fruit juices from a public hospital in Rio de Janeiro. Gram-negative bacteria are worrisome because they are becoming resistant to many antibiotic available options, mainly in hospital environment. Several studies have noted the presence of bacteria producing extended-spectrum beta-lactamase, with the presence of antibiotic-resistance genes in fresh vegetables and fruits. This study aimed to detect the presence of phenotypic and genotypic resistance in eight samples of fresh fruit juices served to patients admitted to a hospital in Rio de Janeiro. The growth of microorganisms on MacConkey and XLD agar was carried out to obtain a "pool" of Gram-negative bacteria. The disk diffusion test and the polymerase chain reaction were performed to detect the phenotypic and genotypic resistance of Gram-negative bacteria to the tested antibiotics. The multidrug resistance was detected in all samples and the shv, tem, ctx, tetA, tetB and oxa- 48 genes were found in the samples, including the presence of class 2 and 3 integrons. We can conclude that the selection methodology allows the detection of a greater number of genes and this found warns about the risk of making these foods available to patients in hospitals.202133398401
171550.9998Transcriptome analysis of beta-lactamase genes in diarrheagenic Escherichia coli. Beta (β)-lactamases are the most important agents that confer drug resistance among gram-negative bacteria. Continuous mutations in β-lactamases make them remarkably diverse. We carried out the transcriptome analysis of 10 β-lactamase genes of Extended-Spectrum β-lactamases (ESBL), Metallo β-lactamases (MBL), and AmpC β-lactamases (ABL) in drug-resistant and sensitive diarrheagenic E. coli (DEC) isolates obtained from children up to 5 years of age. Out of the 10 β-lactamase genes, four belonged to ESBL (TEM, SHV, CTX, and OXA); three to MBL (NDM-1, IMP, and VIM); and three to ABL (ACT, DHA and CMY) class of genes. The different categories of DEC were estimated for β-lactamases production using a set of conventional phenotypic tests, followed by detection of their messenger RNA (mRNA) expression. The study revealed a direct correlation between mRNA expression of these genes and the presence of antibiotic resistance; also corroborated by mutation analysis of the AmpC promoter region. All the 10 β-lactamase genes showed a significant increase in their expression levels in resistant isolates, compared to those of the sensitive isolates, indicating their possible role in the disease pathogenesis. Increase in mRNA expression of β-lactamase genes, and thereby virulence, may be due to multifactorial parameters causing phenotypic as well as genotypic changes. Our study highlights the necessity of instantaneous detection of β-lactamase gene expression to curb the overwhelming threat posed by emergence of drug resistance amongst the commensal E. coli strains in children from developing countries for larger public health interest.201930842518
232760.9998Identification of Quinolone and Colistin Resistance Genes in Escherichia Coli Strains Isolated from Mucosal Samples of Patients with Colorectal Cancer and Healthy Subjects. INTRODUCTION: Antibiotic resistance and extensive use of antibiotics are amongst the major causes of failure in antibiotic treatment. The purpose of this study was to investigate antibiotic resistance patterns and to identify resistance genes of quinolones and colistin in Escherichia coli. There are a very few patents on E. coli isolated from colorectal cancer. So, this study demonstrates that some bacteria resistant to ciprofloxacin have not resistance genes.Moreover, new patterns for E. coli are presented for isolates of patients with colorectal cancer. MATERIALS AND METHODS: Of the three healthy people, inflammatory bowel diseases (IBD) patients and colorectal cancer patients, 40 E. coli strains isolated after confirmation by biochemical and molecular methods. The susceptibility of isolates to antibiotics was investigated using disk diffusion test. After deoxyribonucleic acid (DNA) extraction, polymerase chain reaction (PCR) was used to identify genes encoding resistance to ciprofloxacin (qnr A, qnr B) and colistin (mcr-1). RESULTS: The results showed that E. coli isolates from colorectal cancer patients had the highest resistance to piperacillin (67.5%), ceftazidime (47.5%), and cefepime (42.5%). Also, E. coli strains isolated from IBD patients showed resistance to antibiotic ceftazidime 13%. More than 95% of E. coli strains isolated from healthy people were susceptible to antibiotics. Based on the results, 18 (15%) E. coli strains showed resistance to ciprofloxacin. The qnr A gene was detected in 61.11% isolates; however, qnr B was detected in 9 (50%) isolates. Isolates resistant to colistin were not observed. CONCLUSION: These findings indicate increased resistance of E. coli to ciprofloxacin in comparison with prior studies. Further research in this field will increase our knowledge and more effective exposure to the antibiotic resistance of the pathogenic microorganisms.202031198116
230470.9998Antimicrobial consumption and resistance in five Gram-negative bacterial species in a hospital from 2003 to 2011. BACKGROUND: The misuse of antimicrobial agents increases drug resistance in bacteria. METHODS: The correlation between antimicrobial agent consumption and related resistance in the Gram-negative bacteria Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Proteus mirabilis was analyzed during the period 2003-2011. RESULTS: Among these five bacteria, overall E. coli and K. pneumoniae were more commonly isolated from bloodstream than the other species. Regarding Enterobacteriaceae, E. coli and K. pneumoniae showed annual increases of resistance to the tested antimicrobial agents; conversely, P. mirabilis exhibited reduced resistance to cefuroxime, ceftriaxone and cefepime. In contrast to the relatively low antimicrobial resistance in P. aeruginosa, A. baumannii revealed high resistance, which was over 85% resistant rate to the tested antimicrobial agents and over 80% carbapenem resistance in 2011. E. coli, K. pneumoniae, and P. mirabilis differed in development of antimicrobial resistance after consumption of the antimicrobial agents. K. pneumoniae developed resistance to all antimicrobial groups, whereas resistance in P. mirabilis was not related to any antimicrobial consumption. P. aeruginosa developed resistance to β-lactam antimicrobials and aminoglycosides, whereas A. baumanii developed resistance to carbapenems after their use. CONCLUSION: The development of antimicrobial resistance was related to antimicrobial agents and bacterial species.201524863496
159380.9998Epidemiological Description and Detection of Antimicrobial Resistance in Various Aquatic Sites in Marseille, France. Antibiotic resistance is a worldwide public health concern and has been associated with reports of elevated mortality. According to the One Health concept, antibiotic resistance genes are transferrable to organisms, and organisms are shared among humans, animals, and the environment. Consequently, aquatic environments are a possible reservoir of bacteria harboring antibiotic resistance genes. In our study, we screened water and wastewater samples for antibiotic resistance genes by culturing samples on different types of agar media. Then, we performed real-time PCR to detect the presence of genes conferring resistance to beta lactams and colistin, followed by standard PCR and gene sequencing for verification. We mainly isolated Enterobacteriaceae from all samples. In water samples, 36 Gram-negative bacterial strains were isolated and identified. We found three extended-spectrum β-lactamase (ESBL)-producing bacteria-Escherichia coli and Enterobacter cloacae strains-harboring the CTX-M and TEM groups. In wastewater samples, we isolated 114 Gram-negative bacterial strains, mainly E. coli, Klebsiella pneumoniae, Citrobacter freundii and Proteus mirabilis strains. Forty-two bacterial strains were ESBL-producing bacteria, and they harbored at least one gene belonging to the CTX-M, SHV, and TEM groups. We also detected carbapenem-resistant genes, including NDM, KPC, and OXA-48, in four isolates of E. coli. This short epidemiological study allowed us to identify new antibiotic resistance genes present in bacterial strains isolated from water in Marseille. This type of surveillance shows the importance of tracking bacterial resistance in aquatic environments. IMPORTANCE Antibiotic-resistant bacteria are involved in serious infections in humans. The dissemination of these bacteria in water, which is in close contact with human activities, is a serious problem, especially under the concept of One Health. This study was done to survey and localize the circulation of bacterial strains, along with their antibiotic resistance genes, in the aquatic environment in Marseille, France. The importance of this study is to monitor the frequency of these circulating bacteria by creating and surveying water treatments.202336976002
169590.9998Presence of the blaTEM Gene in Commensal Neisseria spp.: A Possible Cause for the Acquired Drug Resistance Among Pathogenic Respiratory Bacteria. Background The oral microbiome consists of various bacterial genera, with Neisseria spp. being a prominent part of this niche. While Neisseria gonorrhoeae and Neisseria meningitidis are human-restricted pathogens, non-pathogenic Neisseria species like Neisseria sicca, Neisseria perflava, etc., are primarily commensals that can also behave as opportunistic pathogens. With increasing penicillin resistance in commensal Neisseria, there is a concern that these bacteria might harbor resistance genes that can be transferred to other pathogens. This study aimed to characterize the blaTEM gene (encodes for the plasmid-mediated β-lactamase enzyme that hydrolyzes the β-lactam ring) of commensal Neisseria spp. isolated from respiratory samples. Methodology The research was conducted in the Department of Clinical Microbiology at Sri Ramachandra University, Chennai. The specimens used were sputum and throat swabs, which were subjected to a series of phenotypic methods and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) for speciation. The antibiogram was determined using the Kirby-Bauer disk diffusion method, and a PCR assay was utilized to identify the blaTEM( )gene responsible for β-lactamase production. Results Out of 274 processed samples, 65 unique commensal Neisseria spp. were identified. The study highlighted the presence of the blaTEM gene in 93.9% (61) of the isolates, which is responsible for β-lactamase production. All isolates exhibited resistance to penicillin. Most blaTEM-positive commensal Neisseria spp. were susceptible to cefuroxime (83.6%), ceftriaxone (85.2%), and cefotaxime (85.2%). The high prevalence of the blaTEM gene in commensal Neisseria is alarming. The gene, found on plasmids, could potentially transfer to other related species like Neisseria gonorrhoeae and Neisseria meningitidis, as well as other Gram-negative bacilli. Conclusion The presence of resistance genes in commensal bacteria is of concern, as they might be reservoirs for resistance transfer to pathogenic strains. The study emphasizes the importance of continuous monitoring and deeper investigations into commensal bacteria, emphasizing the need for a broader community screening approach to understand resistance mechanisms in the normal microbiome.202338146567
5567100.9998Comparison of Antibiotic Resistance and Virulence Factors among Escherichia coli Isolated from Conventional and Free-Range Poultry. Microbiological contamination in commercial poultry production has caused concerns for human health because of both the presence of pathogenic microorganisms and the increase in antimicrobial resistance in bacterial strains that can cause treatment failure of human infections. The aim of our study was to analyze the profile of antimicrobial resistance and virulence factors of E. coli isolates from chicken carcasses obtained from different farming systems (conventional and free-range poultry). A total of 156 E. coli strains were isolated and characterized for genes encoding virulence factors described in extraintestinal pathogenic E. coli (ExPEC). Antimicrobial susceptibility testing was performed for 15 antimicrobials, and strains were confirmed as extended spectrum of β-lactamases- (ESBLs-) producing E. coli by phenotypic and genotypic tests. The results indicated that strains from free-range poultry have fewer virulence factors than strains from conventional poultry. Strains from conventionally raised chickens had a higher frequency of antimicrobial resistance for all antibiotics tested and also exhibited genes encoding ESBL and AmpC, unlike free-range poultry isolates, which did not. Group 2 CTX-M and CIT were the most prevalent ESBL and AmpC genes, respectively. The farming systems of poultries can be related with the frequency of virulence factors and resistance to antimicrobials in bacteria.201526579536
2227110.9998Prophylactic application of antibiotics selects extended-spectrum β-lactamase and carbapenemases producing Gram-negative bacteria in the oral cavity. Prophylactic administration of broad-spectrum antibiotics in surgery can change the oral microbiome and induce colonization of oral cavity with Gram-negative bacteria including multidrug (MDR) or extensively drug resistant (XDR) organisms which can lead to lower respiratory tract infections. The aim of the study was to analyse the Gram-negative isolates obtained from oral cavity of the mechanically ventilated patients in ICUs, after prophylactic application of antibiotics and their resistance mechanisms and to compare them with the isolates obtained from tracheal aspirates from the same patients. The antibiotic susceptibility was determined by broth dilution method. PCR was applied to detect genes encoding β-lactamases. Marked diversity of Gram-negative bacteria and resistance mechanisms was found. High resistance rates and high rate of bla(CTX-M) and carbapenemase encoding genes (bla(VIM-1) , bla(OXA-48) ) were found among Klebsiella pneumoniae. Pseudomonas aeruginosa was found to harbour bla(VIM) and in one strain bla(PER-1) gene, whereas Acinetobacter baumannii produced OXA-23-like and OXA-24/40-like oxacillinases and was XDR in all except one case. All XDR isolates belong to international clonal lineage II (IC II). The main finding of the study is that the prophlylactic application of antibiotics in surgery intensive care units (ICUs) is associated with the colonization of oral cavity and lower respiratory tract with Gram-negative bacteria. The identity of Gram-negative bacteria in oral cavity reflected those found in endotracheal aspirates leading to conclusion that oral swab as non-invasive specimen can predict the colonization of lower respiratory tract with resistant Gram-negative organisms and the risk for development of ventilator-associated pneumonia.202133896011
2303120.9998Patterns of Drug-Resistant Bacteria in a General Hospital, China, 2011-2016. Drug-resistant bacteria has been a threat to public life and property. We described the trends and changes in antibiotic resistance of important pathogens in a general hospital in Zhengzhou, China from 2011 to 2016, to control antimicrobial-resistant bacteria in hospital and provide support to clinicians and decision-making departments. Five dominant bacteria were enrolled based on the data from the general hospital during 6 years. The results of antimicrobial susceptibility testing were interpreted according to Clinical and Laboratory Standards Institute (CLSI). From 2011 to 2016, a total of 19,260 strains of bacteria were isolated, of which Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii accounted for 51.98%. The resistance rate of K. pneumoniae and E. coli to carbapenem was less than 15%, but resistance of K. pneumoniae to carbapenems increased with time and resistance of E. coli to meropenem increased. The rate of extended-spectrum beta-lactamase (ESBL) production among K. pneumoniae and E. coli was decreasing. For most antibiotics, the resistance rate of ESBL-positive isolates was higher than that of ESBL-negative isolates, excluding carbapenems and cefoxitin. For S. aureus, the rate of methicillin-resistant S. aureus (MRSA) was stable. Resistance of S. aureus to mostly antibiotics decreased with time. Besides polymyxin B, P. aeruginosa and A. baumannii showed high resistance to other antibiotics. For A. baumannii, the resistance rate to mostly antibiotics was increasing. The bacteria showed high levels of resistance and multiple drug resistance. Continuous surveillance and optimizing the use of antibiotics are essential. Drug-resistant bacteria has been a threat to public life and property. We described the trends and changes in antibiotic resistance of important pathogens in a general hospital in Zhengzhou, China from 2011 to 2016, to control antimicrobial-resistant bacteria in hospital and provide support to clinicians and decision-making departments. Five dominant bacteria were enrolled based on the data from the general hospital during 6 years. The results of antimicrobial susceptibility testing were interpreted according to Clinical and Laboratory Standards Institute (CLSI). From 2011 to 2016, a total of 19,260 strains of bacteria were isolated, of which Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii accounted for 51.98%. The resistance rate of K. pneumoniae and E. coli to carbapenem was less than 15%, but resistance of K. pneumoniae to carbapenems increased with time and resistance of E. coli to meropenem increased. The rate of extended-spectrum beta-lactamase (ESBL) production among K. pneumoniae and E. coli was decreasing. For most antibiotics, the resistance rate of ESBL-positive isolates was higher than that of ESBL-negative isolates, excluding carbapenems and cefoxitin. For S. aureus, the rate of methicillin-resistant S. aureus (MRSA) was stable. Resistance of S. aureus to mostly antibiotics decreased with time. Besides polymyxin B, P. aeruginosa and A. baumannii showed high resistance to other antibiotics. For A. baumannii, the resistance rate to mostly antibiotics was increasing. The bacteria showed high levels of resistance and multiple drug resistance. Continuous surveillance and optimizing the use of antibiotics are essential.201931250593
1703130.9998Acinetobacter baumannii clinical isolates from outbreaks in Erbil hospitals after the COVID-19 pandemic. INTRODUCTION: Acinetobacter baumannii is endemic in hospital environments, and since the coronavirus disease 2019 (COVID-19) pandemic, multidrug-resistant A. baumannii has become more potent. This potential evolution is driven by the undetectable numbers of gene resistances it has acquired. We evaluated the antibiotic-resistance genes in isolates from patients in Erbil hospitals. METHODOLOGY: This is the first study to demonstrate the antimicrobial resistance epidemic in Erbil, Iraq. A total of 570 patients, including 100 COVID-19 patients were tested. Isolate identification, characterization, antibiotics susceptibility test, polymerase chain reaction (PCR) amplification of the antibiotic resistance genes in both bacterial chromosome and plasmid, 16S-23S rRNA gene intergenic spacer (ITS) sequencing using the Sanger DNA sequencing, and phylogenetic analysis were used in this study. RESULTS: Only 13% of A. baumannii isolates were from COVID-19 patients. All isolates were multi-drug resistant due because of 24 resistance genes located in both the bacterial chromosome or the plasmid. blaTEM gene was detected in the isolates; however, aadB was not detected in the isolated bacteria. New carbapenemase genes were identified by Sanger sequencing and resistance genes were acquired by plasmids. CONCLUSIONS: The study identified metabolic differences in the isolates; although all the strains used the coumarate pathway to survive. Several resistance genes were present in the isolates' plasmids and chromosome. There were no strong biofilm producers. The role of the plasmid in A. baumannii resistance development was described based on the results.202439499748
2063140.9998Nalidixic acid-a good marker of fluoroquinolone resistance mechanisms in Escherichia coli. The purpose of this study was to evaluate how ciprofloxacin, pefloxacin, and nalidixic acid disks perform in screening fluoroquinolone resistance mechanisms in 278 Escherichia coli isolates collected from a prospective clinical material. Antimicrobial susceptibility testing of ciprofloxacin, pefloxacin, and nalidixic acid was performed with the disk diffusion method. PCR-based and sequencing methods were used to detect chromosomal mutations in the gyrA and parC genes and the presence of plasmid-mediated qnr and aac(6')-1b-cr genes. In addition, whole-genome sequencing was used to confirm these results. Our results show that fluoroquinolone resistance mechanisms were discovered, even in ciprofloxacin-susceptible isolates, and plasmid-mediated low-level fluoroquinolone resistance is easily missed if only ciprofloxacin disk is used. E. coli strains with chromosomal gyrA and/or parC mutations were well detected with pefloxacin disk. However, nalidixic acid was a superior tool to detect and differentiate between low- (plasmid-mediated) and high-level (chromosomal mutations) fluoroquinolone resistance in E. coli. Thus, more clinical studies are needed to evaluate the clinical relevance of fluoroquinolone resistance mechanisms in enteric bacteria and pathogens that show potential but are not yet phenotypically fluoroquinolone-resistant. IMPORTANCE: We show in our clinical setting that fluoroquinolone resistance mechanisms are discovered, even among phenotypically fluoroquinolone-susceptible Escherichia coli isolates. When plasmid-mediated quinolone-resistance determinants are present, they are a potential risk for treatment failures due to accumulation of resistance mechanisms during the antimicrobial treatment. Therefore, when it is clinically relevant, fluoroquinolone resistance mechanisms in E. coli should be monitored more closely, and we also recommend testing nalidixic acid susceptibility.202540401973
2329150.9998Antibiotic resistance and genotyping of clinical group B Salmonella isolated in Accra, Ghana. AIMS: The purpose of this study was to investigate the antibiotic resistance and clonal lineage of serogroup B Salmonella isolated from patients suspected of suffering from enteric fever in Accra, Ghana. METHODS AND RESULTS: Serogroup B Salmonella were isolated from blood (n=28), cerebral spinal fluid (CSF) (n=1), or urine (n=2), and identified based on standard biochemical testing and agglutinating antisera. Isolates were examined for their susceptibility to ampicillin, chloramphenicol, tetracycline and trimethoprim-sulfamethoxazole. Most of the isolates could be classified as multiple-drug resistant. Furthermore, the genetic location of resistance genes was shown to be on conjugative plasmids. Genetic fingerprinting by plasmid profiling, enterobacterial repetitive intergenic consensus (ERIC)-PCR, and repetitive element (REP)-PCR were performed to determine the diversity among the isolates. Plasmid profiling discriminated five unique groupings, while ERIC-PCR and REP-PCR resulted in two and three groupings, respectively. CONCLUSIONS: A high rate of antibiotic resistance was associated with the Salmonella isolates and the genes responsible for the resistance are located on conjugative plasmids. Also, there appears to be minimal diversity associated with the isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: As a result of the increasing antibiotic resistance among bacteria of all genera, surveys to monitor microbial populations are critical to determine the extent of the problem. The inability to treat many infectious diseases with current antibiotic regimens should prompt the medical community to be more prudent with its antibiotic use.200312534821
1572160.9998Phenotypic and Genomic Characterization of AmpC-Producing Klebsiella pneumoniae From Korea. The prevalence of multidrug-resistant gram-negative bacteria has continuously increased over the past few years; bacterial strains producing AmpC β-lactamases and/or extended-spectrum β-lactamases (ESBLs) are of particular concern. We combined high-resolution whole genome sequencing and phenotypic data to elucidate the mechanisms of resistance to cephamycin and β-lactamase in Korean Klebsiella pneumoniae strains, in which no AmpC-encoding genes were detected by PCR. We identified several genes that alone or in combination can potentially explain the resistance phenotype. We showed that different mechanisms could explain the resistance phenotype, emphasizing the limitations of the PCR and the importance of distinguishing closely-related gene variants.201829611388
5513170.9998The genetic background of antibiotic resistance among clinical uropathogenic Escherichia coli strains. The spreading mechanisms of antibiotic resistance are related to many bacterial and environment factors. The overuse of antibiotics is leading to an unceasing emergence of new multidrug resistant strains. This problem also concerns uropathogenic Escherichia coli strains, which is the most common pathogen causing urinary tract infections. The aim of this study was the genetic analysis of antibiotic resistance in comparison to the phenotypic background of E. coli strains. The characterized collection of E. coli strains isolated 10 years ago from the urine samples of patients with urinary tract infections was used for antimicrobial susceptibility testing (the disc diffusion method) and analysis of antibiotic resistance genes (PCR reaction, sequencing). Additionally, the presence of ESBL strains was analyzed. Fourteen genes were associated with resistance to beta-lactams, aminoglycosides, sulfonamides and quinolones. The genetic analysis revealed that bla(TEM-1) and sul2 were present in almost all of the studied strains. Other drug-resistance genes were very rare or non-existent. Otherwise, the phenotypic resistance to fluoroquinolones was well correlated with the genotypic background of the studied bacteria. The presence of particular genes and specific mutations indicate a high bacterial potential to multidrug resistance. On the other hand, it needs to be emphasized that the standard disk diffusion test for the routine antimicrobial susceptibility analysis is still the best way to estimate the current situation of bacterial drug-resistance.201830008141
1716180.9998Detection of clinically important β-lactamases by using PCR. Increasing antimicrobial resistance of nosocomial pathogens is becoming a serious threat to public health. To control the spread of this resistance, it is necessary to detect β-lactamase-producing organisms in the clinical setting. The aims of the study were to design a PCR assay for rapid detection of clinically encountered β-lactamase genes described in Enterobacteriaceae and Gram-negative non-fermenting bacteria. The functionality of proposed primers was verified using eight reference strains and 17 strains from our collection, which contained 29 different β-lactamase genes. PCR products of the test strains were confirmed by Sanger sequencing. Sequence analysis was performed using bioinformatics software Geneious. Overall, 67 pairs of primers for detecting 12 members of the class C β-lactamase family, 15 members of class A β-lactamases, six gene families of subclass B1, one member each of subclasses B2, B3 and class D β-lactamases were designed, of which 43 pairs were experimentally tested in vitro. All 29 β-lactamase genes, including 10 oxacillinase subgroups, were correctly identified by PCR. The proposed set of primers should be able to specifically detect 99.7% of analyzed β-lactamase subtypes and more than 79.8% of all described β-lactamase genes.202134100944
2253190.9998Biofilm Formation and Antibiotic Resistance Profiles in Carbapenemase-Producing Gram-Negative Rods-A Comparative Analysis between Screening and Pathological Isolates. (1) Background: Carbapenem-resistant (CR) bacteria pose a significant global public health challenge due to their ability to evade treatment with beta-lactam antibiotics, including carbapenems. This study investigates the biofilm-forming capabilities of CR clinical bacterial isolates and examines the impact of serum on biofilm formation. Additionally, the study evaluates the resistance profiles and genetic markers for carbapenemase production. (2) Methods: Bacterial isolates were collected from the microbiology laboratory of Mures County Clinical Hospital between October 2022 and September 2023. Pharyngeal and rectal swabs were screened for carbapenem-resistant bacteria using selective media. Lower respiratory tract samples were also analyzed for CR Gram-negative bacteria. The isolates were tested for their ability to form biofilms in the presence and absence of fetal bovine serum at 24 and 48 h. Carbapenemase production was detected phenotypically and confirmed via PCR for relevant genes. (3) Results: Out of 846 screened samples, 4.25% from pharyngeal swabs and 6.38% from rectal swabs tested positive for CR bacteria. Acinetobacter baumannii and Klebsiella pneumoniae were the most common species isolated. Biofilm formation varied significantly between clinical isolates and standard strains, with clinical isolates generally showing higher biofilm production. The presence of serum had no significant effect on biofilm formation in Klebsiella spp., but stimulated biofilm formation for Acinetobacter spp. Carbapenemase genes bla(KPC), bla(OXA-48-like), and bla(NDM) were detected in various isolates, predominantly in Klebsiella spp., but were not the main determinants of carbapenem resistance, at least in screening isolates. (4) Conclusions: This study highlights the variability in biofilm formation among CR clinical isolates and underscores the differences between the bacteria found as carriage versus infection. Both bacterial species and environmental factors variably influence biofilm formation. These insights are crucial for the development of effective treatment and infection control strategies in clinical settings.202439199988