Epidemiology and Mechanism of Drug Resistance of Multidrug-Resistant Klebsiella Pneumoniae Isolated from Patients with Urinary Tract Infection in Beijing Teaching Hospital, China. - Related Documents




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86701.0000Epidemiology and Mechanism of Drug Resistance of Multidrug-Resistant Klebsiella Pneumoniae Isolated from Patients with Urinary Tract Infection in Beijing Teaching Hospital, China. PURPOSE: Klebsiella pneumoniae is an important pathogenic bacterium in causing urinary tract infection. With the overuse of antibiotics, bacteria resistant to quinolones combined with carbapenems are increasing. In this study, we investigated the epidemiology, molecular characteristics, drug resistance of multidrug-resistant Klebsiella pneumoniae (MDR-KPN) isolated from urine samples. It provides theoretical basis for the treatment of urinary tract infection by clinicians. PATIENTS AND METHODS: Fifty-one strains of Klebsiella pneumonia were obtained from urine samples collected between 2012 and 2017 in total. All the strains are multi-drug resistant bacteria. This paper used multilocus sequence typing (MLST) to determine molecular epidemiological typing. We performed antimicrobial susceptibility testing and investigated quinolones and carbapenems resistance genes. RESULTS: The strains which we collected were resistant to ciprofloxacin and Levofloxacin. In an epidemiological analysis using MLST, 86.27% (44/51) of isolates were confirmed to be ST11. The main carbapenem resistance gene was KPC-19, 78.43(40/51). Among the quinolone resistance genes, the major resistance genes were aac(6')-Ib-cr, oqxA and oqxB. CONCLUSION: The main molecular epidemiological types we detected was ST11. The main resistance gene of carbapenems was KPC-19. The quinolone resistance genes are mainly aac(6')-Ib-cr, oqxA and oqxB. The experimental results can help control the use of quinolones and carbapenems, and we could provide rational drug use basis for clinicians to treat urinary tract infection. For MDR-KPN, a combination of multiple antibiotics is necessary.202539803309
86810.9999Antimicrobial susceptibility and genetic characteristics of multi-drug resistant Acinetobacter baumannii isolates in Northwest China. INTRODUCTION: In recent decades, widespread multi-drug resistant (MDR) bacteria have become a serious problem in healthcare facilities. METHODS: To systematically summarize and investigate the prevalence and genomic features of clinical MDR Acinetobacter baumannii (A. baumannii) clinical isolates recovered from the first hospital of Lanzhou University, we collected 50 MDR A. baumannii isolates isolated in the first quarter of 2022 and using whole-genome sequencing investigate the genotypic characteristics. RESULTS: All of these isolates were generally resistant to the common β-lactamase antibiotics. Resistance to cefoperazone-sulbactam varies greatly between different clones. The proportion of CC208 isolates resistant and mediated to cefoperazone-sulbactam is as high as 84.6%. There were no isolates resistant to tigecycline and colistin. The presence of bla(OXA - 23) (94.0%) and bla(OXA - 66) (98.0%) were the most frequent determinants for carbapenem resistance. Two main endemic clones were identified, one (ST469(oxf)) was predominantly circulating in ICUs and carried the same resistance genes, virulence genes and transposons, and the other clone (CC208) carried more resistance genes and had more widely disseminated. DISCUSSION: Our study showed that clinical MDR A. baumannii isolates circulating in our hospital exhibited highly similar genetic features. We should take timely and effective measures to control the further epidemic of these isolates.202438746749
91720.9999Virulence characterization and clonal analysis of uropathogenic Escherichia coli metallo-beta-lactamase-producing isolates. BACKGROUND: Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract infection (UTI); however, treatment of UTI has been challenging due to increased antimicrobial resistance (AMR). One of the most important types of AMR is carbapenem resistance (CR). CR bacteria are known as an important threat to global public health today. Class B metallo-beta-lactamases (MBLs) are one of the major factors for resistance against carbapenems. We aimed to investigate the characteristics of UPEC isolates producing MBL. METHODS: A cross-sectional study was conducted from October 2018 to December 2019 in Ahvaz; Iran. UPEC isolates were identified by biochemical and molecular methods. Metallo-beta-lactamase-producing isolates were detected using modified carbapenem inactivation method (mCIM) and EDTA-CIM (eCIM) tests. MBL genes, phylogenetic group, and virulence genes profile of carbapenem resistant isolates were determined. Conjugation assay and plasmid profiling were conducted to evaluate the ability of transferring of CR to other E. coli isolates. Clonal similarity of isolates were assessed using Enterobacterial intergenic repetitive element sequence (ERIC)-PCR. RESULTS: Among 406 UPEC isolates, 12 (2.95%) carbapenem-resistant were detected of which 11 were phenotypically MBL-producing strains. Four isolates were resistant to all investigated antimicrobial agents and were considered possible pandrug-resistant (PDR). bla(NDM), bla(OXA-48), bla(IMP-1), and bla(IMP-2) genes were found in 9, 5, 1, and 1 isolates, respectively. Among 30 virulence genes investigated, the traT, fyuA followed by fimH, and iutA with the frequency of 8 (66.7%), 8 (66.7%), 7 (58.3%), and 7 (58.3%) were the most identified genes, respectively. Siderophore production was the main virulence trait among carbapenem-resistant UPEC isolates. Except for two, all other isolates showed weak to moderate virulence index. In all recovered isolates, CR was readily transmitted via plasmids to other isolates during conjugation experiments. CONCLUSION: MBL and carbapenemase genes, especially bla(NDM) and bla(OXA-48) are spreading rapidly among bacteria, which can be a threat to global public health. Therefore monitoring the emergence and dissemination of new AMR is necessary to continuously refine guidelines for empiric antimicrobial therapy. Understanding the mechanisms of resistance and virulence in this group of bacteria can play an effective role in providing new therapeutic methods.202134344363
86630.9999Opening Pandora's box: High-level resistance to antibiotics of last resort in Gram-negative bacteria from Nigeria. OBJECTIVES: The aim of this study was to determine the percentage of antimicrobial-resistant isolates and the associated resistance mechanisms in Gram-negative bacteria from South Western Nigeria. METHODS: A total of 306 non-duplicate unbiased Gram-negative isolates were recovered from patients admitted to three teaching hospitals in South Western Nigeria in 2011 and 2013. Isolates were from clinical samples as well as from stool samples of inpatients without infection to assess antimicrobial resistance patterns in carriage isolates. Antimicrobial susceptibility testing was performed, and PCR and sequencing were used to identify genes encoding various known β-lactamases. Based on phenotypic and genotypic results, 10 isolates representing the diversity of phenotypes present were selected for whole-genome sequencing (WGS). RESULTS: Antimicrobial susceptibility testing revealed the following resistance rates: fluoroquinolones, 78.1%; third-generation cephalosporins, 92.2%; and carbapenems, 52.6%. More resistant isolates were isolated from stools of uninfected patients compared with clinical infection specimens. Klebsiella (10%) and Escherichia coli (7%) isolates produced a carbapenemase. WGS of selected isolates identified the presence of globally disseminated clones. CONCLUSION: This study illustrates a crisis for the use of first-line antimicrobial therapy in Nigerian patients. It is likely that Nigeria is playing a significant role in the spread of antimicrobial resistance owing to its large population with considerable global mobility.202031654790
93140.9999Epidemiological characteristics and antimicrobial susceptibility among carbapenem-resistant non-fermenting bacteria in Brazil. INTRODUCTION: Non-fermenting Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii are widespread in the environment and are increasingly associated with nosocomial infections. Extensive and indiscriminate use of antibiotics in hospitals has contributed to an increased number of infections caused by these microorganisms, that are resistant to a wide variety of antimicrobials, including β-lactams. This study aimed to isolate and identify carbapenem-resistant Acinetobacter spp. and P. aeruginosa from hospitalized patients, to determine their antimicrobial susceptibility patterns and to screen for blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, and blaOXA-143 genes among the isolated bacteria. METHODOLOGY: Antimicrobial resistance patterns were performed using the disk-diffusion method. Genetic markers related to carbapenem resistance were screened by polymerase chain reaction. RESULTS: Carbapenem-resistant Acinetobacter spp. (n = 44) and P. aeruginosa (n = 28) samples were isolated from patients admitted to a tertiary hospital. Polymyxin B was the only effective drug for all isolates. Considering the oxacillinase gene screening, genetic markers were observed only in Acinetobacter isolates. The most frequent genotype observed was blaOXA-23+/blaOXA-51+ (45.5%), followed by blaOXA-51+/blaOXA-143+ (41%). The oxacillinase genes blaOXA-24 and blaOXA-58 were not detected. High mortality rates (> 70%) were observed. CONCLUSIONS: The data suggest the need for rational use of antimicrobials associated with early diagnosis of multidrug-resistant bacteria, especially considering non-fermenting Gram-negative rods, which are widespread in hospitals. The findings of blaoxa-51(-) strains suggest the occurrence and spread of non-A. baumannii species throughout our hospitals. Effective implementation of surveillance programs in hospitals is needed to reduce infectious and resistant intra- and inter-species bacteria.201627367001
86350.9999Colistin-resistance genes in Escherichia coli isolated from patients with urinary tract infections. BACKGROUND: The incidence of antimicrobial resistance is alarmingly high because it occurs in humans, environment, and animal sectors from a "One Health" viewpoint. The emergence of plasmid-carried mobile colistin-resistance (MCR) genes limits the efficacy of colistin, which is the last-line treatment for multidrug resistance (MDR) against gram-negative infections. OBJECTIVES: The current study aimed to investigate emergence of colistin-resistance (MCR 1-5) genes in E. coli isolated from patients with urinary tract infections (UTIs) in Jordan. METHODS: E. coli (n = 132) were collected from urine specimens. The E. coli isolated from human UTI patients were examined the resistance to colistin based on the presence of MCR (1-5). All isolates were tested against 20 antimicrobials using the standard disk diffusion method. The broth microdilution technique was used to analyze colistin resistance. In addition, the MCR (1-5) genes were detected using multiplex PCR. RESULTS: Out of the 132 isolates, 1 isolate was colistin-resistant, having a minimum inhibitory concentration of 8 μg/mL and possessing MCR-1. All the E. coli isolates showed high resistance to penicillin (100%), amoxicillin (79.55%), cephalexin (75.76%), nalidixic acid (62.88%), tetracycline (58.33%), or cefepime (53.79). CONCLUSION: To our knowledge, this is the first report on the presence of plasmid-coded MCR-1 in E. coli from a patient with UTIs in Jordan. This is a problematic finding because colistin is the last-line drug for the treatment of infections caused by MDR gram-negative bacteria. There is a crucial need to robustly utilize antibiotics to control and prevent the emergence and prevalence of colistin-resistance genes.202438865304
85960.9999Analysis of mcr family of colistin resistance genes in Gram-negative isolates from a tertiary care hospital in India. AIM: Colistin serves as the drug of last resort for combating numerous multidrug-resistant (MDR) Gram-negative infections. Its efficacy is hampered by the prevalent issue of colistin resistance, which severely limits treatment options for critically ill patients. Identifying resistance genes is crucial for controlling resistance spread, with horizontal gene transfer being the primary mechanism among bacteria. This study aimed to assess the prevalence of plasmid-mediated mcr genes associated with colistin resistance in Gram-negative bacteria, utilizing both genotypic and phenotypic tests. METHODS AND RESULTS: The clinical isolates (n = 913) were obtained from a tertiary care center in Chennai, India. Colistin resistance was seen among Gram-negative isolates. These strains underwent screening for mcr-1, mcr-3, mcr-4, and mcr-5 genes via conventional PCR. Additionally, mcr-positive isolates were confirmed through Sanger sequencing and phenotypic testing. The bacterial isolates predominantly comprised Klebsiella pneumoniae (62.43%), Escherichia coli (19.71%), Pseudomonas aeruginosa (10.73%), and Acinetobacter baumannii (4.81%), along with other species. All isolates exhibited multidrug resistance to three or more antibiotic classes. Colistin resistance, determined via broth microdilution (BMD) using CLSI guidelines, was observed in 13.08% of the isolates studied. Notably, mcr-5 was detected in K. pneumoniae in PCR, despite its absence in Sanger sequencing and phenotypic tests (including the combined-disk test, colistin MIC in the presence of EDTA, and Zeta potential assays). This finding underscores the importance of employing multiple diagnostic approaches to accurately identify colistin resistance mechanisms.202438986507
90970.9999First Description of Colistin and Tigecycline-Resistant Acinetobacter baumannii Producing KPC-3 Carbapenemase in Portugal. Herein, we describe a case report of carbapenem-resistant Acinetobacter baumannii and Klebsiella pneumoniae isolates that were identified from the same patient at a Tertiary University Hospital Centre in Portugal. Antimicrobial susceptibility and the molecular characterization of resistance and virulence determinants were performed. PCR screening identified the presence of the resistance genes bla(KPC-3), bla(TEM-1) and bla(SHV-1) in both isolates. The KPC-3 K. pneumoniae isolate belonged to the ST-14 high risk clone and accumulated an uncommon resistance and virulence profile additional to a horizontal dissemination capacity. In conclusion, the molecular screening led to the first identification of the A. baumannii KPC-3 producer in Portugal with a full antimicrobial resistance profile including tigecycline and colistin.201830404152
86080.9999Investigation of Plasmid-Mediated Colistin Resistance Genes (mcr-1-8) in Enterobacterales Isolates. Background The escalating global rise in multidrug-resistant gram-negative bacteria presents an increasingly substantial threat to patient safety. Over the past decade, carbapenem-resistant Enterobacterales (CRE) have emerged as one of the most critical pathogens in hospital-acquired infections, notably within intensive care units. Colistin has become one of the last-resort antimicrobial agents utilized to combat infections caused by CRE. However, the use of colistin has been accompanied by a notable increase in the prevalence of colistin-resistant bacteria. This study aimed to investigate plasmid-mediated colistin resistance genes ranging from mcr-1 to mcr-8 among members of the Enterobacterales order. Materials and methods This prospective study was conducted in the microbiology laboratory of Afyonkarahisar Health Sciences University Health Research and Practice Center between May 1, 2021 and July 31, 2022. A total of 2,646 Enterobacterales isolates were obtained from all culture-positive clinical samples sent from various clinics. Of these, 79 isolates exhibiting resistance to carbapenem antibiotics were included in the study. Among the 79 isolates, the presence of mcr-1 to mcr-8 genes was investigated in 27 isolates that were shown to be resistant to colistin. The identification of bacteria at the species level and antibiotic susceptibility tests were conducted using the VITEK 2 automated system (bioMérieux, USA). Colistin resistance among Enterobacterales strains exhibiting carbapenem resistance was evaluated using the broth microdilution technique (ComASP™ Colistin, Liofilchem, Italy), in accordance with the manufacturer's instructions. Results In our in vitro investigations, the minimum inhibitory concentration (MIC) values for meropenem were determined to be >8 µg/ml, whereas for colistin, the MIC50 value was >16 µg/ml and the MIC90 value was 8 µg/ml. A total of 27 colistin-resistant strains were identified among the 79 carbapenem-resistant Enterobacterales strains analyzed. The most prevalent agent among colistin-resistant strains was Klebsiella pneumoniae (K. pneumoniae), representing 66.7% of the isolates. This was followed by Proteus mirabilis (P. mirabilis) with 29.6% and Escherichia coli (E. coli) with 3.7%. The colistin resistance rate among carbapenem-resistant strains was found to be 34.2%, with colistin MIC values in strains tested by the broth microdilution method ranging from 4 to >16 µg/ml concentrations. In polymerase chain reaction (PCR) studies, the mcr-1 gene region was successfully detected by real-time PCR in the positive control isolate. Nevertheless, none of the gene regions from mcr-1 to mcr-8 were identified in our study investigating the presence of plasmid-mediated genes using a multiplex PCR kit. Conclusion Although our study demonstrated the presence of increased colistin resistance rates in carbapenem-resistant Enterobacterales isolates, it resulted in the failure to detect genes from mcr-1 to mcr-8 by the multiplex PCR method. Therefore, it is concluded that the colistin resistance observed in Enterobacteriaceae isolates in our region is not due to the mcr genes screened, but to different resistance development mechanisms.202438957246
87090.9999Dissemination of multiple carbapenem-resistant clones of Acinetobacter baumannii in the Eastern District of Saudi Arabia. It has previously been shown that carbapenem-resistant Acinetobacter baumannii are frequently detected in Saudi Arabia. The present study aimed to identify the epidemiology and distribution of antibiotic resistance determinants in these bacteria. A total of 83 A. baumannii isolates were typed by pulsed-field gel electrophoresis (PFGE), and screened by PCR for carbapenemase genes and insertion sequences. Antibiotic sensitivity to imipenem, meropenem, tigecycline, and colistin were determined. Eight different PFGE groups were identified, and were spread across multiple hospitals. Many of the PFGE groups contained isolates belonging to World-wide clone 2. Carbapenem resistance or intermediate resistance was detected in 69% of isolates. The bla VIM gene was detected in 94% of isolates, while bla OXA-23-like genes were detected in 58%. The data demonstrate the co-existence and wide distribution of a number of clones of carbapenem-resistant A. baumannii carrying multiple carbapenem-resistance determinants within hospitals in the Eastern Region of Saudi Arabia.201526191044
923100.9999Prevalence of Oxacillinase Genes in Clinical Multidrug-Resistant Gram-Negative Bacteria. BACKGROUND: The emergence of OXA-type beta-lactamases has become a significant threat to public healthcare systems and may lead to prolonged hospital stays and increased mortality rates among affected patients. This study aimed to determine the prevalence of oxacillinase resistance (OXA) genes in multidrug-resistant (MDR) Gram-negative bacteria. METHODS: One hundred and six clinical isolates were collected from a stock of Gram-negative isolates and were identified and tested for antibiotic susceptibility and presence of OXA genes using polymerase chain reaction (PCR). RESULTS: The most common detected isolate was Klebsiella pneumoniae (36.8%), followed by Escherichia coli (33%), Pseudomonas aeruginosa (16%), and Acinetobacter baumannii (14.2%). Out of these isolates, 97.4%, 87.2%, 84.6%, and 79.5% were resistant to ampicillin/sulbactam, cefotaxime, ceftazidime, and aztreonam, respectively. PCR results confirmed the presence of one or more OXA genes in 34% of the samples studied. The blaOXA-1 and blaOXA-10 genes were the most highly detected genes, followed by blaOXA-4 and blaOXA-51. The total number of Pseudomonas aeruginosa isolates was confirmed to carry at least one OXA gene (70.6%), whereas Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli were confirmed to carry at least one OXA gene (53.3, 28.2, and 22.9%, respectively). There was a significant association (p < 0.05) between the resistance genes and the type of isolate. CONCLUSIONS: Pseudomonas aeruginosa and Acinetobacter baumannii are the most common MDR Gram-negative strains carrying OXA-type beta-lactamase genes. Monitoring of MDR pathogens in Gram-negative bacteria must be continuously undertaken to implement effective measures for infection control and prevention.202540066541
919110.9999Molecular Characteristics of Carbapenem-Resistant Enterobacter cloacae in Ningxia Province, China. The emergence of carbapenem-resistant Enterobacteriaceae (CRE) has become a major public health concern worldwide and a new challenge in the treatment of infectious diseases. The molecular characteristics of Enterobacter cloacae in Ningxia China are unknown. In this study, we reported 10 carbapenem-resistant E. cloacae isolates from the General Hospital of Ningxia Medical University, the largest university hospital in Ningxia between January 2012 and December 2013. Bacteria isolates were identified by Vitek2 compact and the identity of non-duplicate E. cloacae isolates was further confirmed by PCR and sequencing. The drug susceptibility and phenotype identification of these isolates were analyzed by agar dilution method, modified Hodge test (MHT), and EDTA synergy test. Beta-lactamase (bla) genes bla(NDM-1) was found in 8 out of 10 isolates. Most isolates harbored multiple resistance genes including bla(ESBL), bla(AmpC), quinolones, aminoglycosides, and disinfectant resistance genes. Pulsed field gel electrophoresis (PFGE) showed that these E. cloacae isolates were grouped into 6 clusters based on a cutoff of 80% genetic similarity. In conjugative assay, 9 out of 10 isolates transferred carbapenem-resistant genes to Escherichia coli. Our study has revealed that NDM-1-producing isolates are the most prevalent carbapenem-resistant E. cloacae in Ningxia. These isolates also carry several other carbapenem-resistant genes and can transfer these genes to other bacteria through conjugation. These findings highlight an urgent need to monitor these isolates to prevent their further spread in this region.201728197140
930120.9999Isolation of Carbapenem and Colistin Resistant Gram-Negative Bacteria Colonizing Immunocompromised SARS-CoV-2 Patients Admitted to Some Libyan Hospitals. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a devastating effect, globally. We describe, for the first time, the occurrence of carbapenem-resistant bacteria colonizing SARS-CoV-2 patients who developed hospital-associated infections with carbapenemase-producing, Gram-negative bacteria at some isolation centers of SARS-CoV-2 in the eastern part of Libya. In total, at first, 109 samples were collected from 43 patients, with the samples being recovered from oral (n = 35), nasal (n = 45), and rectal (n = 29) cavities. Strain identification was performed via matrix assisted laser desorption ionization-time of flight (MALDI-TOF). Antibiotic susceptibility testing was carried out on Mueller-Hinton agar, using the standard disk diffusion method. MIC determination was confirmed via E-TEST and microdilution standard methods. A molecular study was carried out to characterize the carbapenem and colistin resistance in Gram-negative bacterial strains. All of the positive results were confirmed via sequencing. Klebsiella pneumoniae (n = 32), Citrobacter freundii (n = 21), Escherichia coli (n = 7), and Acinetobacter baumannii (n = 21) were the predominant isolated bacteria. Gram-negative isolates were multidrug-resistant and carried different carbapenem resistance-associated genes, including NDM-1 (56/119; 47.05%), OXA-48 (15/119; 12.60%), OXA-23 (19/119; 15.96%), VIM (10/119; 8.40%), and the colistin resistance mobile gene mcr-1 (4/119; 3.36%). The overuse of antimicrobials, particularly carbapenem antibiotics, during the SARS-CoV-2 pandemic has led to the emergence of multidrug-resistant bacteria, mainly K. pneumoniae, A. baumannii, and colistin-resistant E. coli strains. Increased surveillance as well as the rational use of carbapenem antibiotics and, recently, colistin are required to reduce the propagation of multidrug-resistant strains and to optimally maintain the efficacy of these antibiotics. IMPORTANCE In this work, we describe, for the first time, the occurrence of carbapenem-resistant bacteria colonizing COVID-19 patients who developed hospital-associated infections with carbapenemase-producing, Gram-negative bacteria at some isolation centers of COVID-19 in the eastern part of Libya. Our results confirmed that the overuse of antimicrobials, such as carbapenem antibiotics, during the COVID-19 pandemic has led to the emergence of multidrug-resistant bacteria, mainly K. pneumoniae and A. baumannii, as well as colistin resistance.202337042782
2158130.9999Relationship of OqxAB efflux pump to antibiotic resistance, mainly fluoroquinolones in Klebsiella pneumoniae, isolated from hospitalized patients. OBJECTIVES: This research was designed to study the prevalence of OqxAB efflux pump genes and also to investigate the relationship between efflux pump and resistance to antibiotics, especially to fluoroquinolones, evaluate the expression levels of OqxAB genes, and molecular typing of Klebsiella pneumoniae isolated from hospitalized patients in Hamadan hospitals, west of Iran. MATERIALS AND METHODS: In a cross-sectional study, 100 clinical strains of K. pneumoniae were isolated from hospitalized patients in three major teaching hospitals from January to June 2021. The antibiotic susceptibility of isolates was evaluated by the disk-diffusion agar method. The frequency of genes encoding oqxA and oqxB of efflux pump genes was investigated by PCR, and the expression of the oqxA efflux pump gene was investigated by the Real-time PCR method. The genetic relationship of K. pneumoniae isolates was analyzed by the Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR technique. RESULTS: According to our results, the multi-drug resistance phenotype (MDR) in 65% and high prevalence resistance to ciprofloxacin in 89% of K. pneumoniae isolates was detected. The higher prevalence of oqxA (95%) and oqxB (98%) was also detected. There was a significant relationship between ciprofloxacin resistance and the oqxB gene as well as between ceftriaxone and chloramphenicol resistance and the oqxA gene. The expression of the oqxA gene was higher in ciprofloxacin-resistant isolates. CONCLUSION: The results of this study suggest a potential reservoir for the spread of OqxAB genes among hospital-acquired bacteria. Infection control strategies should be used prudently to reduce the spread of resistant strains of K. pneumoniae in hospitals.202336594055
897140.9999Prevalence of class 1 integrons and plasmid-mediated qnr-genes among Enterobacter isolates obtained from hospitalized patients in Ahvaz, Iran. Quinolones are frequently used classes of antimicrobials in hospitals, crucial for the treatment of infections caused by Gram-negative bacteria. The inappropriate use of quinolones and other antimicrobial agents for the treatment of bacterial infections leads to a significant increase of resistant isolates. The acquisition of antimicrobial resistance may be related to achievement of resistance determinant genes mediated by plasmids, transposons and gene cassettes in integrons. The objective of this cross-sectional study, conducted from December 2015 to July 2016 at two teaching hospitals in Ahvaz, southern Iran, was to screen for the presence of class 1 integrons and quinolone resistance genes in clinical isolates of Enterobacter spp. In all, 152 non-duplicated Enterobacter isolates were collected from clinical specimens and identified as Enterobacter spp. using standard microbiological methods. Antimicrobial susceptibility test was determined using the disc diffusion method according to the CLSI recommendation. Determination of class 1 integrons and PMQR genes was assessed by PCR. Analysis of antibiotic susceptibility tests showed that the highest antibiotic resistance was toward ciprofloxacin (55.3%), while the lowest level was observed against meropenem (34.9%). Moreover, 47.4% (72/152) and 29% (44/152) of isolates were positive for class 1 integron and quinolone resistance genes, respectively. The relative frequencies of antibiotic resistance were significantly higher among class 1 integron-positive isolates. In summary, our results highlight the importance of PMQR genes in the emergence of quinolone-resistant Enterobacter isolates. Moreover, it seems that class 1 integrons have a widespread distribution among Enterobacter isolates and have clinical relevance to multiple-drug-resistant isolates.201729286015
932150.9999Emergence of armA and rmtB genes among VIM, NDM, and IMP metallo-β-lactamase-producing multidrug-resistant Gram-negative pathogens. In the recent years, it has been noted that microorganisms with acquired resistance to almost all available potent antibiotics are increasing worldwide. Hence, the use of antibiotics in every clinical setup has to be organized to avoid irrational use of antibiotics. This study was aimed to establish the pattern of antibiotic sensitivity and relevance of antimicrobial resistance in aerobic Gram-negative bacilli. A total of 103 aerobic Gram-negative bacteria namely Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Citrobacter koserii, Proteus spp., and Pseudomonas aeruginosa were collected from tertiary care centers around Chennai. Kirby-Bauer Disk Diffusion test and study for genes of cephalosporin, carbapenem, and aminoglycoside resistance were done. A descriptive analysis of the data on altogether 103 clinical urine isolates was performed. All strains showed susceptibility to colistin. The frequency of genes encoding 16S rRNA methylases armA and rmtB were 7.8% and 6.8%, respectively. Among metallo-β-lactamases, bla(VIM), bla(IMP), and bla(NDM-1) were detected in 6.8%, 3.8%, and 3.8%, respectively. One E. coli strain harbored bla(SIM-1) gene. Cumulative analysis of data suggested that 30% of the strains carried more than one resistance gene. The current research evidenced the increasing frequency of resistance mechanisms in India. Combined approach of antibiotic restriction, effective surveillance, and good infection control practices are essential to overcome antibiotic resistance.201828870092
914160.9999Investigation of colistin heteroresistance and the colistin resistance genes mcr-1 to mcr-5 in Escherichia coli and Klebsiella pneumoniae isolates in a tertiary hospital in Turkey. INTRODUCTION: Heteroresistance is not detected by traditional antimicrobial susceptibility testing methods and may lead to treatment failures. Investigating the presence of plasmid-mediated colistin resistance genes is important because of the horizontal transmission of the relevant genes between bacterial species. This study aimed to investigate the presence of colistin heteroresistance and the colistin resistance genes mcr-1 to mcr-5 in Escherichia coli and Klebsiella pneumoniae isolates. METHODOLOGY: A total of 254 isolates, including 100 E. coli and 154 K. pneumoniae strains isolated from clinical samples, were included in the study. Colistin susceptibility was evaluated using the broth microdilution method for all strains. Heteroresistance screening was performed using the gradient strip test. Eight strains were evaluated for heteroresistance by population analysis profiling (PAP). The colistin resistance genes mcr-1 to mcr-5 were investigated by multiplex polymerase chain reaction (PCR) in colistin-resistant K. pneumoniae isolates. Multilocus sequence typing (MLST) analysis was performed on two K. pneumoniae strains. RESULTS: Colistin resistance was not detected in the E. coli isolates and was detected in 16.23% (25/154) of the K. pneumoniae isolates. No heteroresistant bacteria were detected by the gradient strip test or by PAP. All colistin-resistant isolates were negative for the mcr genes. The two isolates analyzed by MLST were ST14 and ST2096. CONCLUSIONS: Periodic follow-up of colistin heteroresistance is useful for administering appropriate antibiotic therapy. In addition, the investigation of colistin resistance genes is important for infection control measures.202439693153
871170.9998Comparative De Novo and Pan-Genome Analysis of MDR Nosocomial Bacteria Isolated from Hospitals in Jeddah, Saudi Arabia. Multidrug-resistant (MDR) bacteria are one of the most serious threats to public health, and one of the most important types of MDR bacteria are those that are acquired in a hospital, known as nosocomial. This study aimed to isolate and identify MDR bacteria from selected hospitals in Jeddah and analyze their antibiotic-resistant genes. Bacteria were collected from different sources and wards of hospitals in Jeddah City. Phoenix BD was used to identify the strains and perform susceptibility testing. Identification of selected isolates showing MDR to more than three classes on antibiotics was based on 16S rRNA gene and whole genome sequencing. Genes conferring resistance were characterized using de novo and pan-genome analyses. In total, we isolated 108 bacterial strains, of which 75 (69.44%) were found to be MDR. Taxonomic identification revealed that 24 (32%) isolates were identified as Escherichia coli, 19 (25.3%) corresponded to Klebsiella pneumoniae, and 17 (22.67%) were methicillin-resistant Staphylococcus aureus (MRSA). Among the Gram-negative bacteria, K. pneumoniae isolates showed the highest resistance levels to most antibiotics. Of the Gram-positive bacteria, S. aureus (MRSA) strains were noticed to exhibit the uppermost degree of resistance to the tested antibiotics, which is higher than that observed for K. pneumoniae isolates. Taken together, our results illustrated that MDR Gram-negative bacteria are the most common cause of nosocomial infections, while MDR Gram-positive bacteria are characterized by a wider antibiotic resistance spectrum. Whole genome sequencing found the appearance of antibiotic resistance genes, including SHV, OXA, CTX-M, TEM-1, NDM-1, VIM-1, ere(A), ermA, ermB, ermC, msrA, qacA, qacB, and qacC.202337894090
883180.9998Detection of plasmid-mediated colistin resistance, mcr-1 gene, in Escherichia coli isolated from high-risk patients with acute leukemia in Spain. BACKGROUND: Bacterial infections in immunocompromised patients are associated with a high mortality and morbidity rate. In this high-risk group, the presence of multidrug-resistant (MDR) bacteria, particularly bacteria that harbor a transferable antibiotic resistance gene, complicates the management of bacterial infections. In this study, we investigated the presence of the transferable colistin resistance mcr genes in patients with leukemia in Spain. METHODS: 217 fecal samples collected in 2013-2015 from 56 patients with acute leukemia and colonized with MDR Enterobacteriaceae strains, were screened on September 2017 for the presence of the colistin resistance mcr genes (mcr-1 to -5) by multiplex PCR. mcr positive strains selected on LBJMR and MacConkey supplemented with colistin (2 μg/ml) media were phenotypically and molecularly characterized by antimicrobial susceptibility testing, minimum inhibitory concentration, multilocus sequence typing and plasmid characterization. RESULTS: Among 217 fecal samples, 5 samples collected from 3 patients were positive for the presence of the mcr-1 colistin-resistance gene. Four Escherichia coli strains were isolated and exhibited resistance to colistin with MIC = 4 μg/ml. Other genes conferring the resistance to β-lactam antibiotics have also been identified in mcr-1 positive strains, including bla(TEM-206) and bla(TEM-98). Three different sequence types were identified, including ST1196, ST140 and ST10. Plasmid characterization allowed us to detect the mcr-1 colistin resistance gene on conjugative IncP plasmid type. CONCLUSION: To the best of our knowledge, we have identified the mcr-1 gene for the first time in leukemia patients in Spain. In light of these results, strict measures have been implemented to prevent its dissemination.201931023570
2150190.9998Analysis of drug resistance genes of integrons in clinical isolates of Escherichia coli from elderly bloodstream infections. This experiment was carried out to provide a basis for the treatment of clinical bloodstream infections by analyzing the drug resistance characteristics and integrated gene distribution of Escherichia coli in bloodstream infections in elderly patients. For this aim, E. coli were collected for bacterial identification and drug sensitivity testing from bloodstream infections in elderly patients in the hospital from January 2016 to December 2019. ESBLs positive strains were assayed for genotypes and their integron carriage rates by PCR amplification. The characteristics and differences of various genotype rates were compared and analyzed. Results showed that a total of 230 E. coli strains were isolated. The detection rate of ESBLs-producing bacteria was 37.39 %. ESBLs-producing E. coli showed a high rate of resistance to cefepime, levofloxacin, cotrimoxazole, and ticarcillin/clavulanic acid (>40%). The resistance rate of 230 strains of E. coli to meropenem, minocycline, amikacin, gentamicin and cefoxitin was less than 20%. Among the ESBLs-producing E. coli in bloodstream infections in elderly patients, CTX-M-9 accounted for 27.91%, CTX-M-2 for 17.44%, and SHV for 13.95%. The detection rate of type I integrated genes was 41.30%, and type II and III integrated genes were not detected. ESBLs-producing genotyping-positive bacteria were detected with more than 50% of type I integrated genes. It was concluded that type I integrated genes in ESBLs-producing E. coli isolated from elderly patients carried resistance genes such as CTX-M-9 and CTX-M-2 aggravating multi-drug resistance in bacteria.202236227675