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Microorganisms Jun 2024is an opportunistic pathogen causing lifethreatening infections in humans, particularly in immunocompromised patients, neonates and the elderly. We report a case of...
is an opportunistic pathogen causing lifethreatening infections in humans, particularly in immunocompromised patients, neonates and the elderly. We report a case of central line-associated bloodstream infection by in a 2.5-year-old girl with acute lymphoblastic leukemia successfully treated with a combination of piperacillin/tazobactam and amikacin. The literature was also reviewed on pediatric infections caused by , focusing on clinical manifestations, underlying medical conditions, treatment and outcome. Accurate identification with MALDI-TOF, or using molecular techniques, is of the utmost importance because treatment and prognosis differ depending on the species. Considering that is multiresistant to antibiotics and that inappropriate antimicrobial therapy is an independent risk factor for mortality, the early, accurate identification of bacterial species and prompt effective treatment are essential to achieve optimal therapeutic outcomes.
PubMed: 38930527
DOI: 10.3390/microorganisms12061145 -
Antibiotics (Basel, Switzerland) May 2024Carbapenemase-producing (CP-KP) represents a global threat to public health, with limited antimicrobial therapeutic options. In this study, we analyzed a...
BACKGROUND
Carbapenemase-producing (CP-KP) represents a global threat to public health, with limited antimicrobial therapeutic options. In this study, we analyzed a ceftazidime/avibactam (CAZ-AVI)-resistant isolate obtained from a patient previously exposed to CAZ-AVI expressing a novel carbapenemase (KPC)-3 variant.
METHODS
Antimicrobial susceptibility testing was performed using reference broth microdilution. Whole-genome sequencing (WGS) was performed using Illumina and Nanopore Technologies. Short- and long-reads were combined with Unicycler. Assemblies were investigated for multilocus sequence typing (MLST), antimicrobial resistance genes, porins, and plasmids.
RESULTS
The . isolate (KP_RM_1) was resistant to CAZ-AVI, expanded-spectrum cephalosporins, amikacin, ertapenem, and cefiderocol (FDC) but was susceptible to tigecycline, colistin, trimethoprim/sulfamethoxazole, meropenem-vaborbactam, and imipenem-relebactam. WGS revealed that the KP_RM_1 genome is composed of a single chromosome of 5 Mbp and five circular plasmids. Further analysis showed the presence of novel located on a 72 kb plasmid. KPC-216 differs from KPC-3 by a Lysin (K) insertion at position 168 (+K168).
CONCLUSIONS
We report the identification of a new KPC-3 variant associated with CAZ-AVI resistance. The KPC variants associated with CAZ-AVI resistance should be determined to promptly inform clinicians and start the appropriate antimicrobial therapy.
PubMed: 38927174
DOI: 10.3390/antibiotics13060507 -
Antibiotics (Basel, Switzerland) May 2024The discovery of novel therapeutic agents, especially those targeting mycobacterial membrane protein large 3 (), has shown promise. In this study, the CRISPR...
BACKGROUND
The discovery of novel therapeutic agents, especially those targeting mycobacterial membrane protein large 3 (), has shown promise. In this study, the CRISPR interference- nuclease-deactivated Cas9 (CRISPRi-dCas9) system was utilized to suppress expression in , and its impacts on susceptibility to antimicrobial agents were evaluated.
METHODS
The repression of the gene was confirmed by RT-qPCR. The essentiality, growth curve, viability, and antimicrobial susceptibility of the knockdown strain were investigated.
RESULTS
silencing was achieved by utilizing 0.5 and 1 ng/mL anhydrotetracycline (ATc), resulting in reductions in the expression of 60.4% and 74.4%, respectively. silencing led to a significant decrease in bacterial viability when combined with one-half of the minimal inhibitory concentrations (MICs) of rifampicin, rifabutin, ceftriaxone, or isoniazid, along with 0.1 or 0.5 ng/mL ATc ( < 0.05). However, no significant difference was observed for clarithromycin or amikacin.
CONCLUSIONS
The downregulation of the gene in mycobacteria was achieved through the use of CRISPRi-dCas9, resulting in growth deficiencies and resensitization to certain antimicrobial agents. The impact was dependent upon the level of gene expression.
PubMed: 38927150
DOI: 10.3390/antibiotics13060483 -
International Journal of... Apr 2024Tuberculosis (TB), a global infectious threat, has seen a concerning rise in aminoglycoside-resistant Mycobacterium tuberculosis (M.tb) strains. The potential role of... (Comparative Study)
Comparative Study
Comparative Proteomic Analysis of Capsule Proteins in Aminoglycoside-Resistant and Sensitive Mycobacterium tuberculosis Clinical Isolates: Unraveling Potential Drug Targets.
BACKGROUND
Tuberculosis (TB), a global infectious threat, has seen a concerning rise in aminoglycoside-resistant Mycobacterium tuberculosis (M.tb) strains. The potential role of capsule proteins remains largely unexplored. This layer acts as the primary barrier for tubercle bacilli, attempting to infiltrate host cells and subsequent disease development.
METHODS
The study aims to bridge this gap by investigating the differentially expressed capsule proteins in aminoglycoside-resistant M.tb clinical isolates compared with drug-sensitive isolates employing two-dimensional gel electrophoresis, mass spectrometry, and bioinformatic approaches.
RESULTS
We identified eight proteins that exhibited significant upregulation in aminoglycoside-resistant isolates. Protein Rv3029c and Rv2110c were associated with intermediary metabolism and respiration; Rv2462c with cell wall and cell processes; Rv3804c with lipid metabolism; Rv2416c and Rv2623 with virulence and detoxification/adaptation; Rv0020c with regulatory functions; and Rv0639 with information pathways. Notably, the Group-based Prediction System for Prokaryotic Ubiquitin-like Protein (GPS-PUP) algorithm identified potential pupylation sites within all proteins except Rv3804c. Interactome analysis using the STRING 12.0 database revealed potential interactive partners for these proteins, suggesting their involvement in aminoglycoside resistance. Molecular docking studies revealed suitable binding between amikacin and kanamycin drugs with Rv2462c, Rv3804c, and Rv2623 proteins.
CONCLUSION
As a result, our findings illustrate the multifaceted nature of aminoglycoside resistance in M.tb and the importance of understanding how capsule proteins play a role in counteracting drug efficacy. Identifying the role of these proteins in drug resistance is crucial for developing more effective treatments and diagnostics for TB.
Topics: Mycobacterium tuberculosis; Humans; Proteomics; Bacterial Proteins; Aminoglycosides; Drug Resistance, Bacterial; Bacterial Capsules; Antitubercular Agents; Microbial Sensitivity Tests; Computational Biology; Electrophoresis, Gel, Two-Dimensional; Tuberculosis
PubMed: 38916392
DOI: 10.4103/ijmy.ijmy_47_24 -
Perioperative Medicine (London, England) Jun 2024Secondary peritonitis is the second leading cause of sepsis worldwide. Drug resistance to peritoneal cavity bacterial infection remains a public health threat,...
INTRODUCTION
Secondary peritonitis is the second leading cause of sepsis worldwide. Drug resistance to peritoneal cavity bacterial infection remains a public health threat, especially in resource-limited settings in Africa, including Uganda. This study aimed to determine the antibacterial susceptibility patterns and factors associated with secondary peritonitis among patients with acute abdomen who underwent surgery at a Regional Referral Hospital in Uganda.
METHODS
This was a cross-sectional study conducted at Hoima Regional Referral Hospital (HRRH) that enrolled 126 patients with acute abdomen. Clinical samples were aseptically collected at laparotomy from patients with secondary peritonitis for culture and sensitivity using standard Microbiological methods. Binary logistic regression was used to identify factors associated with secondary peritonitis among patients with acute abdomen.
RESULTS
The majority of the patients were males (61.9%) with a mean age of 37.9(SD ± 21.8). Secondary peritonitis was found in 57(45.2%) of the patients. Gram-negative bacteria were the most commonly isolated organisms with Escherichia coli (35.8%) and Klebsiella spp (17.0%) predominating. Imipenem 88.8%(8/9), Amikacin 88.8%(8/9), Ciprofloxacin 44.4%(4/9) and Gentamicin 44.4%(4/9) demonstrated sensitivity to the different isolated organisms at varying degrees. Being a male (AOR = 3.658; 95% CI = 1.570-8.519, p = 0.003) and presenting 3 days after onset of symptoms (AOR = 2.957; 95% CI = 1.232-7.099, p = 0.015) were independently associated with secondary peritonitis.
CONCLUSION
Imipenem, Amikacin, Ciprofloxacin, and Gentamicin should be considered for empirical therapy in cases of secondary peritonitis. Patients, more especially males with abdominal pain should be encouraged to present early to the hospital to minimize progression to secondary peritonitis.
PubMed: 38915124
DOI: 10.1186/s13741-024-00425-4 -
BMC Infectious Diseases Jun 2024Acinetobacter baumannii is a health threat due to its antibiotic resistance. Herein, antibiotic susceptibility and its association with the Toxin-antitoxin (TA) system...
Evaluating the antibacterial effect of meropenem-loaded chitosan/sodium tripolyphosphate (TPP) nanoparticles on Acinetobacter baumannii isolated from hospitalized patients.
BACKGROUND
Acinetobacter baumannii is a health threat due to its antibiotic resistance. Herein, antibiotic susceptibility and its association with the Toxin-antitoxin (TA) system genes in A. baumannii clinical isolates from Iran were investigated. Next, we prepared meropenem-loaded chitosan nanoparticles (MP-CS) and investigated their antibacterial effects against meropenem-susceptible bacterial isolates.
METHODS
Out of 240 clinical specimens, 60 A. baumannii isolates were assessed. Antibiotic resistance of the isolates against conventional antibiotics was determined alongside investigating the presence of three TA system genes (mazEF, relBE, and higBA). Chitosan nanoparticles were characterized in terms of size, zeta potential, encapsulation efficiency, and meropenem release activity. Their antibacterial effects were assessed using the well diffusion method, minimum inhibitory concentration (MIC), and colony-forming unit (CFU) counting. Their cytotoxic effects and biocompatibility index were determined via the MTT, LDH, and ROS formation assays.
RESULTS
Ampicillin, ceftazidime, and colistin were the least effective, and amikacin and tobramycin were the most effective antibiotics. Out of the 60 isolates, 10 (16.7%), 5 (8.3%), and 45 (75%) were multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR), respectively. TA system genes had no significant effect on antibiotic resistance. MP-CS nanoparticles demonstrated an average size of 191.5 and zeta potential of 27.3 mV alongside a maximum encapsulation efficiency of 88.32% and release rate of 69.57%. MP-CS nanoparticles mediated similar antibacterial effects, as compared with free meropenem, against the A. baumannii isolates with significantly lower levels of meropenem. MP-CS nanoparticles remarkably prevented A549 and NCI-H292 cell infection by the A. baumannii isolates alongside demonstrating a favorable biocompatibility index.
CONCLUSION
Antibiotic-loaded nanoparticles should be further designed and investigated to increase their antibacterial effect against A. baumannii and assess their safety and applicability in vivo settings.
Topics: Acinetobacter baumannii; Meropenem; Chitosan; Anti-Bacterial Agents; Humans; Microbial Sensitivity Tests; Nanoparticles; Acinetobacter Infections; Iran; Polyphosphates
PubMed: 38914964
DOI: 10.1186/s12879-024-09522-7 -
PloS One 2024Current antimicrobial susceptibility testing (AST) requires 16-24 hours, delaying initiation of appropriate antibiotics. Hence, there is a need for rapid AST. This study...
Can flow cytometric measurements of reactive oxygen species levels determine minimal inhibitory concentrations and antibiotic susceptibility testing for Acinetobacter baumannii?
Current antimicrobial susceptibility testing (AST) requires 16-24 hours, delaying initiation of appropriate antibiotics. Hence, there is a need for rapid AST. This study aims to develop and evaluate the feasibility of a rapid flow cytometric AST assay to determine minimum inhibitory concentration (MIC) for carbapenem-resistant Acinetobacter baumannii (CRAB). Antibiotic exposure causes increased intracellular reactive oxygen species (ROS) in bacteria. We hypothesized that ROS can be used as a marker to determine MIC. We assessed three CRAB clinical isolates across fifteen antibiotics at various concentrations in a customized 96-well microtiter plate. The antibiotics assessed include amikacin, beta-lactams (ampicillin/sulbactam, aztreonam, cefepime, ceftolozane/tazobactam, doripenem, imipenem, meropenem, and piperacillin/tazobactam), levofloxacin, polymyxin B, rifampicin, trimethoprim/sulfamethoxazole, and tetracyclines (tigecycline and minocycline). These clinical CRAB isolates were assessed for ROS after antibiotic treatment. Increased ROS levels indicated by increased RedoxSensorTM Green (RSG) fluorescence intensity was assessed using flow cytometry (FCM). MIC was set as the lowest antibiotic concentration that gives a ≥1.5-fold increase in mode RSG fluorescence intensity (MICRSG). Accuracy of MICRSG was determined by comparing against microtiter broth dilution method performed under CLSI guidelines. ROS was deemed accurate in determining the MICs for β-lactams (83.3% accuracy) and trimethoprim/sulfamethoxazole (100% accuracy). In contrast, ROS is less accurate in determining MICs for levofloxacin (33.3% accuracy), rifampicin (0% accuracy), amikacin (33.3% accuracy), and tetracyclines (33.3% accuracy). Collectively, this study described an FCM-AST assay to determine antibiotic susceptibility of CRAB isolates within 5 hours, reducing turnaround time up to 19 hours.
Topics: Acinetobacter baumannii; Flow Cytometry; Microbial Sensitivity Tests; Anti-Bacterial Agents; Reactive Oxygen Species; Humans; Carbapenems; Acinetobacter Infections
PubMed: 38913680
DOI: 10.1371/journal.pone.0305939 -
Clinical Microbiology and Infection :... Jun 2024Tuberculosis (TB) is the leading cause of mortality by an infectious disease world-wide. Despite national and international efforts, the world is not on track to end TB... (Review)
Review
BACKGROUND
Tuberculosis (TB) is the leading cause of mortality by an infectious disease world-wide. Despite national and international efforts, the world is not on track to end TB by 2030. Antibiotic treatment of TB is longer than for most infectious diseases and complicated by frequent adverse events. To counter emerging Mycobacterium tuberculosis drug resistance and provide effective, safe drug treatments of shorter duration, novel anti-TB medicines and treatment regimens are needed. Through a joint global effort, more candidate medicines are in the clinical phases of drug development than ever before.
OBJECTIVES
To review anti-TB medicines and treatment regimens under clinical evaluation for the future treatment of drug-susceptible and drug-resistant TB.
SOURCES
Pre-clinical and clinical studies on novel anti-TB drugs.
CONTENT
Description of novel protein synthesis inhibitors (oxazolidinones and oxaboroles), respiratory chain inhibitors (diarylquinolines and cytochrome bc1 complex inhibitor), cell wall inhibitors (DprE1 inhibitors, thioamides and carbapenems) and cholesterol metabolism inhibitor currently evaluated in clinical trials and novel clinical trial platforms for the evaluation of treatment regimens, rather than single entities.
IMPLICATIONS
A large number of potential anti-TB candidate medicines and innovations in clinical trial design for the evaluation of regimens, rather than single medicines, provide hope for improvements in the treatment of TB.
PubMed: 38909687
DOI: 10.1016/j.cmi.2024.06.016 -
Journal of Global Antimicrobial... Jun 2024Ceftolozane-tazobactam (C/T) is a combination of a cephalosporin and a β-lactamase inhibitor with activity against Gram-negative bacilli (GNB). The study aims were to...
In vitro activity of ceftolozane/tazobactam against Gram-negative bacilli isolated from pediatric patients: results from the Study for Monitoring Antimicrobial Resistance Trends (SMART) 2017-2021, China.
OBJECTIVES
Ceftolozane-tazobactam (C/T) is a combination of a cephalosporin and a β-lactamase inhibitor with activity against Gram-negative bacilli (GNB). The study aims were to evaluate the activity of C/T in vitro vs. comparators against clinical GNB isolated from Chinese pediatric patients.
METHODS
From 2017-2021, 660 GNB isolates were collected from 20 hospitals across China. The minimum inhibitory concentrations were tested using a Trek Diagnostic System (Thermo Fisher Scientific). Susceptibility was determined by CLSI broth microdilution and the results were interpreted according to CLSI M100 (2021) breakpoints.
RESULTS
GNB isolates were obtained from pediatric patients < 18 years old, mainly from the bloodstream (n=146), intraperitoneal cavity (n=138), lower respiratory (n=278) and urinary tract (n=96). Overall, C/T was active against 76.6% of 436 Enterobacterales, with a descending susceptibility rate of 100.0% to S. marcescens, 92.2% to E. coli, 83.3% to K. oxytoca, 66.7% to K. aerogenes, 66.7% to P. mirabilis, 58.6% to K. pneumoniae and 57.1% to E. cloacae. The susceptibility of P. aeruginosa to C/T was 89.4%, which was the highest among the β-lactams and was second only to amikacin (92.9%). Isolates of respiratory tract infection (RTI) derived P. aeruginosa were highly susceptible (93.8%) to C/T, while < 75% of isolates of RTI derived P. aeruginosa were susceptible to the other β-lactams tested, except for ceftazidime-avibactam (91.2%).
CONCLUSION
GNBs collected from pediatric patients in China showed a high susceptibility to C/T making this drug combination an effective choice for treating the pediatric population, especially those infected with P. aeruginosa.
PubMed: 38908824
DOI: 10.1016/j.jgar.2024.05.017 -
Microbial Pathogenesis Jun 2024Severe infection caused by Carbapenem-resistant Enterobacteriaceae (CRE) is a challenge for clinical anti-infective therapy, and clinical intervention to improve control...
OBJECTIVES
Severe infection caused by Carbapenem-resistant Enterobacteriaceae (CRE) is a challenge for clinical anti-infective therapy, and clinical intervention to improve control of CRE is of great significance. The study aims to determine the molecular epidemiology and risk factors of CRE infections to provide evidence for effective control of nosocomial infection in patients with CRE.
METHODS
A total of 192 non-repetitive CRE strains were collected from January 2020 to December 2021 in Northwest China. To explore the risk factors of CRE infection by univariate and Logistic regression analysis, 1:1 case-control study was used to select Carbapenem sensitive Enterobacteriaceae (CSE) infection patients at the same period as the control group.
RESULTS
Among the 192 CRE strains, the most common isolates included Klebsiella pneumoniae (Kpn) and Enterobacter cloacae (Ecl). The CRE strain showed the lowest rate of resistance to amikacin at 58.3. 185 CRE strains carried carbapenemase resistance genes of concern in this study. KPC-2 (n=94) was the most common carbapenemase, followed by NDM-1 (n=69), NDM-5 (n=22) and IMP-4 (n=5). OXA-48 and VIM were not detected. And KPC-2 was the most common in all strains. Logistic regression analysis implicated days of invasive ventilator-assisted ventilation (OR=1.452; 95 % CI 1.250~1.686), antibiotic combination therapy (OR=2.149; 95 % CI 1.128~4.094), hypoalbuminemia (OR=6.137; 95 % CI 3.161~11.913), history of immunosuppressant use (OR=25.815; 95 % CI 6.821~97.706) and days of hospitalization (OR=1.020; 95 % CI 1.006~1.035) as independent risk factors associated with CRE infection. Age (OR=0.963; 95% CI 0.943~0.984) and history of hormone use (OR=0.119; 95 % CI 0.028~0.504) were protective factors for CRE infection (P < 0.05).
CONCLUSIONS
The resistance of commonly used antibiotics in clinical is severe, and CRE strains mainly carry KPC-2 and NDM-1. Multiple risk factors for CRE infection and their control can effectively prevent the spread of CRE.
PubMed: 38906492
DOI: 10.1016/j.micpath.2024.106728