High Levels Of Antibiotic Resistance Research Articles

Antimicrobial Bacterial Metabolites: Properties, Applications and Loading in Liposomes for Site-specific Delivery.

The high levels of antibiotic resistance registered worldwide have become a serious health problem, threatening the currently available treatments for a series of infectious diseases. With antibiotics becoming less and less effective, it is becoming increasingly difficult and, in some cases, impossible to treat patients with even common infectious diseases, such as pneumonia. The inability to meet the ever-increasing demand to control microbial infection requires both the search for new antimicrobials and improved site-specific delivery. On the one hand, bacterial secondary metabolites are known for their diverse structure and antimicrobial potential and have been in use for a very long time in diverse sectors. A good deal of research is produced annually describing new molecules of bacterial origin with antimicrobial properties and varied applications. However, very few of these new molecules reach the clinical phase and even fewer are launched in the market for use. In this review article, we bring together information on these molecules with potential for application, in particular, for human and veterinary medicine, and the potential added value of the use of liposomes as delivery systems for site-specific delivery of these drugs with the synergistic effect to overcome the risk of antibiotic resistance.

Resistance pattern of isolated microorganisms from 783 clinical specimen cultures in patients admitted to Yasuj Educational Hospitals, Iran

BackgroundInfectious diseases are still one of the leading causes of morbidity and mortality in resource-limited settings. Serious infection caused mostly by gram-negative pathogens causes significant morbidity. According to the Centers for Disease Control and Prevention, antimicrobial resistance kills over 700,000 people worldwide. Antibiotic resistance is on the rise, and as a consequence, serious public health issues are arising. The present study investigated isolated clinical samples from Yasuj teaching hospitals to determine the antimicrobial resistance profile to various antibiotics.Materials and methodsMicrobial isolates regarding cultures from urine, blood, wound, abdominal tap, throat, stool, cerebrospinal fluid, endotracheal tube, sputum, skin lesion, nasal, and mouth secretion were collected from patients admitted to hospitals affiliated with Yasuj teaching hospitals. Antibiotic susceptibility profiles were determined by using the Kirby-Bauer disc diffusion method. Data were tabulated and analyzed with SPSS version 26.0.ResultsA total of 783 samples were evaluated in our study, with an average of 30.6 years and 54.5% female patients. Most of the bacterial isolates were gram-negative (64.2%). The majority of cultures were Escherichia coli (49.9%), mainly among urine samples (64.2%). The frequency distribution of norfloxacin antibiotic resistance was more common in internal medicine (66.7%), infectious (63.6%), and emergency wards (58.8%). The frequency distribution of penicillin antibiotic resistance was statistically significant in different wards. All cases of oxacillin were resistant.ConclusionOur data showed a high level of antibiotic resistance among bacterial isolates in our center. Considering widespread empirical antibiotic therapy in Iran, the rate of increasing resistance to common antibiotics prescribed for ambulatory and hospitalized patients is concerning. We recommend providing more strict guidelines and policies to control the overuse and overprescription of antimicrobials by health policy-making organizations.

Prevalence of Carbapenemases in Carbapenem-Resistant Acinetobacter baumannii Isolates from the Kingdom of Bahrain.

Acinetobacter baumannii is regarded as a significant cause of death in hospitals. The WHO recently added carbapenem-resistant Acinetobacter baumannii (CRAB) to its global pathogen priority list. There is a dearth of information on CRAB from our region. Fifty CRAB isolates were collected from four main hospitals in Bahrain for this study. Bacterial identification and antibiotic susceptibility tests were carried out using the BD PhoenixTM and VITEK-2 compact, respectively. Using conventional PCR, these isolates were further screened for carbapenem resistance markers (blaOXA-51, blaOXA-23, blaOXA-24, blaOXA-40, blaIMP, blaNDM, blaVIM, and blaKPC). All of the isolates were resistant to imipenem (100%), meropenem (98%), and cephalosporins (96-98%), followed by other commonly used antibiotics. All these isolates were least resistant to gentamicin (64%). The detection of resistance determinants showed that the majority harbored blaOXA-51 (100%) and blaIMP (94%), followed by blaOXA-23 (82%), blaOXA-24 (46%), blaOXA-40 (14%), blaNDM (6%), blaVIM (2%), and blaKPC (2%). The study isolates showed a high level of antibiotic resistance. Class D carbapenemases were more prevalent in our CRAB isolate collection. The resistance genes were found in various combinations. This study emphasizes the importance of strengthening surveillance and stringent infection control measures in clinical settings to prevent the emergence and further spread of such isolates.

Overexpression of blaGES-1 due to a strong promoter in the class 1 integron contributes to decreased ceftazidime-avibactam susceptibility in carbapenem-resistant Pseudomonas aeruginosa ST235.

Sequence type 235 (ST235) Pseudomonas aeruginosa, harboring so-called international, high-risk, or widespread clones, is associated with relatively high morbidity and mortality, partly due to multiantibiotic and high-level antibiotic resistance. Treatment of infections caused by such strains with ceftazidime-avibactam (CZA) is often successful. However, CZA resistance in carbapenem-resistant P. aeruginosa (CRPA) strains has been consistently reported with the increasing use of this drug. Likewise, we identified thirty-seven CZA-resistant ST235 P. aeruginosa strains from among 872 CRPA isolates. A total of 10.8% of the ST235 CRPA strains were resistant to CZA. Site-directed mutagenesis, cloning, expression, and whole-genome sequencing analysis revealed that overexpression of blaGES-1, which was carried in a class 1 integron of the complex transposon Tn6584, occurred due to a strong promoter, contributing to CZA resistance. Moreover, such overexpression of blaGES-1 combined with an efflux pump resulted in high-level resistance to CZA, considerably reducing the therapeutic options available for treating infections caused by ST235 CRPA. Considering the widespread presence of ST235 P. aeruginosa strains, clinicians should be aware of the risk of CZA resistance development in high-risk ST235 P. aeruginosa. Surveillance initiatives for preventing further dissemination of high-risk ST235 CRPA isolates with CZA resistance are essential.

Frequency of mutations in erm(39) related toclarithromycin resistance and in rrl related tolinezolid resistance in clinical isolates ofMycobacterium fortuitum in Iran.

Mycobacterium fortuitum is a clinically important species among nontuberculous mycobacteria (NTM). Treatment of diseases caused by NTM is challenging. The aim of this study was identification of drug susceptibility and detection of mutations in erm(39) related to clarithromycin resistance and in rrl related to linezolid resistance in clinical isolates of M. fortuitum in Iran. In the study, 328 clinical NTM isolates were subjected to identification based on rpoB and 15% of isolates were assigned to M. fortuitum. Minimum inhibitory concentration for clarithromycin and linezolid was determined by E-test. Altogether 64% of M. fortuitum isolates showed resistanc to clarithromycin and 18% of M. fortuitum isolates showed resistance to linezolid. PCR and DNA sequencing were performed in erm(39) and in rrl genes for detection of mutations related to clarithromycin and linezolid resistance, respectively. Sequencing analysis revealed (84.37%) single nucleotide polymorphisms in the erm(39). A total 55.55% of M. fortuitum isolates harbored an A→G, 14.81% harbored an C→A, 29.62% harbored an G→T mutation in erm(39) at position 124, 135, 275. Seven strains harbored point mutation in the rrl gene either at T2131C or at A2358G. Our findings showed M. fortuitum isolates have become a serious problem with high-level antibiotic resistance. The existence of drug resistance to clarithromycin and linezolid indicates more attention to the study of drug resistance in M. fortuitum.

Identification by Reverse Vaccinology of Three Virulence Factors in Burkholderia cenocepacia That May Represent Ideal Vaccine Antigens.

The Burkholderia cepacia complex comprises environmental and clinical Gram-negative bacteria that infect particularly debilitated people, such as those with cystic fibrosis. Their high level of antibiotic resistance makes empirical treatments often ineffective, increasing the risk of worst outcomes and the diffusion of multi-drug resistance. However, the discovery of new antibiotics is not trivial, so an alternative can be the use of vaccination. Here, the reverse vaccinology approach has been used to identify antigen candidates, obtaining a short-list of 24 proteins. The localization and different aspects of virulence were investigated for three of them-BCAL1524, BCAM0949, and BCAS0335. The three antigens were localized in the outer membrane vesicles confirming that they are surface exposed. We showed that BCAL1524, a collagen-like protein, promotes bacteria auto-aggregation and plays an important role in virulence, in the Galleria mellonella model. BCAM0949, an extracellular lipase, mediates piperacillin resistance, biofilm formation in Luria Bertani and artificial sputum medium, rhamnolipid production, and swimming motility; its predicted lipolytic activity was also experimentally confirmed. BCAS0335, a trimeric adhesin, promotes minocycline resistance, biofilm organization in LB, and virulence in G. mellonella. Their important role in virulence necessitates further investigations to shed light on the usefulness of these proteins as antigen candidates.

Blood culture and profile of inflammatory biomarkers among COVID-19 patients in an intensive care unit of a tertiary care hospital

Introduction and Aim: This is a retrospective study to analyse the pathogens causing bacteraemia in COVID-19 patients and its correlation with inflammatory biomarkers such as procalcitonin (PCT), C-reactive protein (CRP), total WBC counts (TC) and D-dimer. The objectives of this study were to evaluate the blood culture positivity rate, to identify the pathogens causing bacteraemia, to analyse their antibiogram and to assess the significance of inflammatory markers along with patient outcomes. Materials and Methods: This study included 165 COVID-19-positive patients admitted to the Intensive care unit (ICU) of a tertiary care hospital from June to September 2020. Blood culture, identification and antibiotic sensitivity testing (AST) were done using automated systems. Values of D-dimer, CRP, PCT and TC were obtained using immunoturbidimetric assay, chemiluminescent immunoassay, immunochromatographic testing and automated haematology analyser respectively. Results: Among 143 blood culture samples obtained from 122 COVID-19 positive patients, 80 flagged positive. Out of the 80 isolates obtained, 53 (66.25%), 17 (21.25%) and 10 (12.5%) were gram-positive bacteria, gram-negative bacteria and candida respectively. The blood culture positivity rate was 25.4%. Acinetobacter spp. and K. pneumoniae showed high levels of antibiotic resistance. Among 16 patients with elevated PCT, 15 (93.7%) patients showed positive blood cultures. CRP of >5 mg/L and deranged total WBC counts were seen among all blood culture-positive patients. In 100 patients with elevated D-dimer, 54% (54/100) patients showed positive blood culture. Conclusion: From this study, we conclude that early identification of pathogens and initiation of appropriate antimicrobial therapy is crucial for managing sepsis associated with COVID-19 infection. PCT, CRP, TC and D-dimer can help as biomarkers in the management of COVID-19 patients with secondary bloodstream infections (BSI).

Assessment of potential pathogenic bacterial load and multidrug resistance in locally manufactured cosmetics commonly used in Dhaka metropolis

In Bangladesh cosmetics are being produced disregarding the Good Manufacturing Practices. So, this study aimed to test the level and nature of bacterial contamination of such cosmetics. A total of 27 cosmetics comprising eight lipsticks, nine powders, and ten creams were bought from New Market and Tejgaon areas of Dhaka city and tested. Bacteria was detected in 85.2% of samples. Majority of the samples (77.8%) exceeded the limit given by the Bangladesh Standards and Testing Institution (BSTI), Food and Drug Administration (FDA) and the International Organization for Standardization (ISO). Both Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella spp.) and Gram-positive bacteria (species of Streptococcus, Staphylococcus, Bacillus and Listeria monocytogenes) were identified. Hemolysis was observed in 66.7% Gram-positive and 25% Gram-negative bacteria. Multidrug resistance was tested in 165 randomly selected isolates. Every species of Gram-positive and Gram-negative bacteria exhibited varying levels of multidrug resistance. The highest levels of antibiotic resistance were in broad-spectrum antibiotics (ampicillin, azithromycin, cefepime, ciprofloxacin and meropenem) and narrow-spectrum Gram-negative antibiotics (aztreonam and colistin). Multidrug resistance was 12–78% in Gram-negative bacteria and 12–100% in Gram-positive bacteria. Coagulase and DNase were identified in 97.5% and 5.1% of Staphylococcus aureus isolates respectively. Our findings indicate that these cosmetics pose a risk to the public’s health.

Novel Chimeric Endolysin Conjugated Chitosan Nanocomplex as a Potential Inhibitor Against Gram-Positive and Gram-Negative Bacteria.

Resistance to antimicrobial agents has created potential problems in finding efficient treatments against bacteria. Thus, using new therapeutics, such as recombinant chimeric endolysin, would be more beneficial for eliminating resistant bacteria. The treatment ability of these therapeutics can be further improved if they are used with biocompatible nanoparticles like chitosan (CS). In this work, covalently conjugated chimeric endolysin to CS nanoparticles (C) and non-covalently entrapped endolysin in CS nanoparticles (NC) were effectively developed and, consequently, qualified and quantified using analytical devices, including FT-IR, dynamic light scattering, and TEM. Eighty to 150 nm and 100 nm to 200 nm in diameter were measured for CS-endolysin (NC) and CS-endolysin (C) using a TEM, respectively. The lytic activity, synergistic interaction, and biofilm reduction potency of nano-complexes were investigated on Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa) strains. The outputs revealed a good lytic activity of nano-complexes after 24 h and 48 h of treatment, especially in P. aeruginosa (approximately 40% cell viability after 48 h of treatment with 8 ng/mL), and potential biofilm reduction performance was attained in E. coli strains (about 70% reduction after treatment with 8 ng/mL). The synergistic interaction between nano-complexes and vancomycin was exhibited in E. coli, P. aeruginosa, and S. aureus strains at 8 ng/mL concentrations, while the synergistic effects of pure endolysin and vancomycin were not remarkable in E. coli strains. These nano-complexes would be more beneficial in suppressing the bacteria with a high level of antibiotic resistance.

Pseudomonas isolates from raw milk with high level proteolytic activity display reduced carbon substrate utilization and higher levels of antibiotic resistance

Milk is an ideal food but can be easily contaminated during milking, transportation and storage by Pseudomonas spp. That secrete proteases resulting in milk spoilage. However, genomic features and functional metabolic diversity of Pseudomonas with different protease activity have not been extensively studied. With this aim, the genomic features and functional metabolic diversity of Pseudomonas with differing proteolytic activity were evaluated using whole genome sequencing and metabolomic approaches, respectively as well as, the presence of genes encoding the aprX protease and antibiotic resistance were screened. Pseudomonas strains with higher protease activity possessed more carbohydrate transport and metabolism, signal transduction, secondary metabolite synthesis, polysaccharide lyase and carbohydrate esterase genes. These isolates were more efficient at carbon source utilization and this phenotype was positively related to incubation temperature. The high protease activity group also displayed a multidrug resistance index that was significantly higher than that for the low protease activity group. This is the first report comparing the gene function and metabolic diversity of Pseudomonas with differing levels of proteolytic activity in raw milk.

Serogroup and Pathogenicity Island Marker Distributions Among Uropathogenic Escherichia coli Isolates in Rasht, Iran

Background: Urinary tract infections (UTIs) are among the most prevalent infections in hospitals and communities worldwide. Objectives: Due to the medical importance of UTIs caused by uropathogenic Escherichia coli (UPEC), this study aimed to investigate pathogenicity island (PAI) markers, O-antigen serogroups, and resistance to antibiotic agents associated with UPEC isolates obtained from hospitalized patients in Rasht city hospitals. Methods: A total of 110 urine samples were taken from patients with UTI referred to selected hospitals in Rasht, Iran. The double-disk synergy test (DDST) was used to detect the isolate’s ability to produce extended-spectrum β-lactamase (ESBL). Using particular primers, eight PAIs were detected (ie, PAI I536, PAI II536, PAI III536, PAI IV536, PAI ICFT073, PAI IICFT073, PAI IJ96, and PAI IIJ96). Results: According to the antibiotic susceptibility pattern, a high level of antibiotic resistance was observed against nalidixic acid (81.8%) and co-trimoxazole (78.2%), while the most effective agent was amikacin (85.5%). Double-disk synergy test revealed that the incidence of ESBL-positive strains was 62.7% (69/110). Of the 110 UPEC isolates, 106 (96.4%) carried at least one of the investigated PAI markers. Uropathogenic E. coli isolates with PAI IV536 (81.8%) had the highest prevalence, and PAI J196 (6.4%) had the lowest PAI marker. The most predominant serogroup O was O25 (36.4%), followed by O16 (17.3%), while the O4 and O7 serogroups (0.9%) were the lowest serogroups among UPEC isolates. Conclusions: The characterization of our strain revealed the co-occurrence of PAI and serogroups, confirming the importance of antibiotic resistance among the distinct serogroups and PAI markers. Our results have potential application for epidemiological studies and designing UTI treatment strategies against UTIs caused by UPEC.

Monitoring and features of antibiotic resistance during the COVID-19 pandemic

Background. Urinary tract infection (UTI) is an urgent problem in nephrology. The current state of antibiotic resistance to antimicrobial drugs complicates the empirical choice of antibacterial therapy, and indications for the use of antimicrobial drugs are not always clinically justified. The purpose of the study: to compare the antibiotic resistance of the main groups of UTI pathogens during coronavirus 2019 (COVID-19) pandemic in 2020–2022 with the results of 2014–2016 monitoring among children of the Chernivtsi region. Materials and methods. Urine samples were collected from 657 children (0–17 years old) who received specialized medical care in health care institutions of the Chernivtsi region (2014–2016). During 2020–2022, a clinical and laboratory examination of 180 children (0–17 years old) was conducted. Results. The results of the monitoring proved the wave-like nature of changes in antibiotic resistance to semi-synthetic penicillins and cephalosporins with the maintenance of a sufficient level of sensitivity to these antimicrobial drugs among the main groups of UTI pathogens; the data obtained give reason to suggest a negative trend to increasing resistance to fluoroquinolones, tetracyclines over time (2020–2022 — the period of the COVID-19 pandemic); a multidirectional and time-dependent differences were revealed in sensitivity to aminoglycosides: gentamicin, amikacin and kanamycin in children of Chernivtsi region, as well as a negative trend to increasing the share of carbapenem-resistant strains of uropathogens — 55.8 ± 5.1 % (imipenem — χ2 = 5.432; p = 0.020). Conclusions. The monitoring results indicate the need to comply with standards in the provision of medical care (prescribing antibacterial therapy taking into account the data of regional monitoring on antibiotic resistance to antimicrobial drugs), administration of antimicrobial drugs in health care institutions that provide medical care in outpatient and inpatient settings. High level of antibiotic resistance of UTI uropathogens to carbapenems (2020–2022), used for the treatment of severe bacterial infections, requires their exclusively targeted prescription in everyday pediatric practice.

ORGANISMS CAUSING OSTEOMYELITIS AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN AMONG PATIENTS SEEKING CARE ATA TERTIARY CARE ORTHOPEDIC CENTER

Objective: The objective of this study was to study the organisms causing osteomyelitis and their antimicrobial susceptibility pattern from a tertiary care teaching hospital located in a region of Madhya Pradesh. Methods: Fifty clinically diagnosed cases of osteomyelitis visiting the medical college and seeking care for the same in orthopedics department during the study period formed the study population. Pus samples were collected and sent to microbiology laboratory for culture and testing of their antimicrobial susceptibility as per the standard guidelines. Results: Out of 50 water samples gathered, 25, 14, and 11 samples of water were gathered from municipal tap water, government hand pump, and water cooler separately. Close to half of the examples were viewed as inadmissible. Escherichia coli was viewed as answerable for 26% of tests while Pseudomonas in 1/5th of gathered examples. Staphylococcus aureus, 14 (87.5%) were found resistant to Penicillin-G. Pseudomonas aeruginosa, 14 (100%) were found resistant to ampicillin, whereas more than half cases were found be resistant to antibiotics, namely, ciprofloxacin, ofloxacin, and cephotaxime, respectively. Conclusion: We observed changes in the patterns of isolated organisms and the establishment of higher levels of antibiotic resistance among bacterial isolates in osteomyelitis cases. It is imperative that monitoring be prioritized to track etiological changes and to adhere to a single health policy to stop the multidrug-resistant bacteria threat.

Bacterial profile, their antibiotic susceptibility pattern, and associated factors of urinary tract infections in children at Hiwot Fana Specialized University Hospital, Eastern Ethiopia.

Urinary tract infections (UTIs) are common pediatric infections and contribute to high morbidity and mortality. At present, the antimicrobial resistance emergency has quadrupled worldwide and poses a serious threat to the treatment of patients. However, there have been few studies on UTIs in children in Ethiopia, particularly in the east. This study aimed to assess the bacterial profile of urinary tract infections, their susceptibility to antimicrobial agents, and associated factors in under-five children at Hiwot Fana Specialized University Hospital, eastern Ethiopia. We conducted hospital-based quantitative study on 332 consecutively selected under-five children from March 20 to June 10, 2021. Parents and guardians were interviewed to collect data using a structured questionnaire. Random urine samples were collected aseptically, and standard microbiological techniques were used to identify the bacteria and test for susceptibility to various antibiotics. Data were entered into Epi Info version 7 and exported to Statistical Package for the Social Sciences (SPSS) version 25 for analysis. Data were analyzed using descriptive analysis, bivariate, and multivariable logistic regression analysis. The crude odds ratio (COR) and adjusted odds ratio (AOR) with their respective 95% confidence intervals (CI) were used to determine the significance of the predictors. A p-value at a 95% confidence interval of less than 0.05 was considered statistically significant. The overall prevalence of bacterial urinary tract infections was 80 (24.1%) 95% CI:19.40-29.00%). Most of the bacterial isolates 55 (68.75%) were gram-negative bacteria, predominantly E. coli 23 (28.75%) and K. pneumoniae 10 (12.50%). Being a rural resident (AOR: 4.10, 95%CI: 1.45 11.54), uncircumcised male (AOR: 3.52, 95%CI: 1.33, 9.39), previous history of antibiotic usage (AOR: 7.32, 95%CI: 2.11, 25.37), indwelling catheterization (AOR: 10.35, 95%CI: 3.74, 28.63), previous history of urinary tract infections (AOR: 5.64, 95% CI: 1.36, 23.38), and urinary frequency (AOR: 5.56, 95%CI: 2.03, 15.25) had higher odds of culture positive result. The majority of the isolates have shown high levels of antibiotic resistance. Meropenem, ciprofloxacin, and amoxicillin-clavulanic acid were effective against gram-negative uropathogens, whereas rifampin and ciprofloxacin were the most sensitive drugs for gram-positive isolates. From the tested bacterial isolates, 53/86 (61.6%), 11/86 (11.6%), and 2/86 (2.3%) were found to have multidrug resistance (MDR), extreme drug resistance (XDR), and pan drug resistance (PDR), respectively. About one-fourth of the children were culture-positive for many types of bacterial uropathogens; this is higher compared with most of the previous studies in Africa. Rural dwellers, uncircumcised males, indwelling catheterization, a history of antibiotic use and urinary tract infection, and frequent urination all had a higher risk of bacterial infections. Many isolates were resistant to multiple drugs, primarily beta-lactams. Urinary tract infections as well as the growth and spread of resistant bacterial pathogens should be monitor regularly.

The Spreading of Antibiotic-Resistant Bacteria in Terrestrial Ecosystems and the Formation of Soil Resistome

Terrestrial ecosystems play a crucial role in the formation of soil resistome and the spread of antibiotic-resistant bacteria. Comprehensive studies of soil microbial communities, their structure, integrity, and level of antibiotic resistance (AR) in various terrestrial ecosystems were conducted. In total, 389 strains of dominant bacteria were isolated from the studied ecosystems, 57 of which were resistant to antibiotics, with levels of antibiotic resistance exceeding 70%. The soil microbiome of primeval forests was characterized by a low content of bacteria resistant to antibiotics; only two species, Bacillus cereus and Pantoea agglomerans, showed a high resistance to antibiotics. In the soil of agroecosystems of medicinal plants, among 106 strains of bacteria, a high level of resistance to antibiotics was found in 13 species. It was established that the number of antibiotic-resistant bacteria is highest in the soil of agroecosystems contaminated by enrofloxacin. Among 190 tested bacterial strains, 42 (22%) were characterized by a high level of antibiotic resistance. Therefore, the soil ecosystem is a key link in the formation and spread of antibiotic-resistant bacteria, which is a potential danger to humans. To reduce the risk of AR for humans, it is necessary to take appropriate measures to manage the soil microbiome and avoid soil contamination with antibiotics.

Genome-encoded ABCF factors implicated in intrinsic antibiotic resistance in Gram-positive bacteria: VmlR2, Ard1 and CplR.

Genome-encoded antibiotic resistance (ARE) ATP-binding cassette (ABC) proteins of the F subfamily (ARE-ABCFs) mediate intrinsic resistance in diverse Gram-positive bacteria. The diversity of chromosomally-encoded ARE-ABCFs is far from being fully experimentally explored. Here we characterise phylogenetically diverse genome-encoded ABCFs from Actinomycetia (Ard1 from Streptomyces capreolus, producer of the nucleoside antibiotic A201A), Bacilli (VmlR2 from soil bacterium Neobacillus vireti) and Clostridia (CplR from Clostridium perfringens, Clostridium sporogenes and Clostridioides difficile). We demonstrate that Ard1 is a narrow spectrum ARE-ABCF that specifically mediates self-resistance against nucleoside antibiotics. The single-particle cryo-EM structure of a VmlR2-ribosome complex allows us to rationalise the resistance spectrum of this ARE-ABCF that is equipped with an unusually long antibiotic resistance determinant (ARD) subdomain. We show that CplR contributes to intrinsic pleuromutilin, lincosamide and streptogramin A resistance in Clostridioides, and demonstrate that C. difficile CplR (CDIF630_02847) synergises with the transposon-encoded 23S ribosomal RNA methyltransferase Erm to grant high levels of antibiotic resistance to the C. difficile 630 clinical isolate. Finally, assisted by uORF4u,our novel tool for detection of upstream open reading frames, we dissect the translational attenuation mechanism that controls the induction of cplR expression upon an antibiotic challenge.

Evaluation of the Risk Factors of Nosocomial Pneumonia and the Prevalence of Antibiotic Resistance in Trauma Patients in Need of Immediate Intervention

Background: Pneumonia is the most common nosocomial infection reported worldwide in intensive care units. This study aimed to evaluate the risk factors of nosocomial pneumonia and the frequency of antibiotic resistance in trauma patients who need immediate intervention. Patients and Methods: This prospective cohort study was conducted in Shahid Rajaei Trauma Hospital in Shiraz between 2020 and 2021. All the trauma patients who needed immediate intervention (levels 1 and 2 based on the Canadian Emergency Department Triage and Acuity Scale) and had no symptoms of infection were included. Patients who were discharged or died before 48 hours were excluded. Results: The results demonstrated that major trauma (Injury Severity Score [ISS] ≥16), intubation, and use of invasive mechanical ventilation increase nosocomial pneumonia and death rate. The most common causes of nosocomial infections were Acinetobacter baumannii (23%) and coagulase-negative staphylococcus (18.5%). The highest levels of antibiotic resistance were related to cefoxitin, erythromycin, ciprofloxacin, and trimethoprim-sulfamethoxazole. Conclusions: Major trauma, intubation, and invasive mechanical ventilation were the effective factors in the development of nosocomial pneumonia. Continuous monitoring for mentioned risk factors and strict surveillance of antibiotic prescription can decrease the prevalence of nosocomial infections and subsequent deaths.

Effect of high-copper diet on transference of bla CTX-M genes among Escherichia coli strains in rats' intestine.

Both ceftiofur (CTO) and high copper are widely utilized in animal production in China, and the occurrence of CTX-M-carrying Escherichia coli in food-producing animals is increasing. There are some specific associations between in-feed high-level copper and antibiotic resistance, but research in Gram-negative bacteria such as E. coli remains scarce. This study aimed to evaluate the effect of high-copper diet on the horizontal transfer of bla CTX-M-1 among E. coli. A total of 32 male SPF rats aged 21 days were randomly assigned to the following four groups: control (6 mg/kg in-feed copper, C-), high copper (240 mg/kg in-feed copper, H-), CTO (6 mg/kg in-feed copper with oral CTO administration, C+), and high copper plus CTO (240 mg/kg in-feed copper with oral CTO administration, H+). All rats were orally inoculated with an E. coli strain harboring a conjugative plasmid carrying bla CTX-M-1, and the C+ and H+ groups were given 10 mg/kg of body weight (BW) CTO hydrochloride at 26, 27, and 28 days, while the C- and H- groups were given salad oil at the same dose. Fecal samples collected at different time points were used for the enumeration of E. coli on Mac plates or for molecular analysis using PCR, pulsed-field gel electrophoresis (PFGE), S1-PFGE, and Southern-blot hybridization. The results showed that the number of the bla CTX-M-1 gene in the H- group was higher and that the loss speed of this gene was slower compared with the C- group. After administration of CTO, the counts of cefotaxime-resistant E. coli were significantly higher in the C+ group than that in the corresponding control group (C+ vs. C-; H+ vs. H-). In the in vitro test, the results showed that the transfer rates of the conjugation induced by the H- (12 mmol/L) group were significantly higher than that of low copper (2 mmol/L) group. The indigenous sensitive isolates, which were homologous to the bla CTX-M-positive isolates of rat feces, were found by PFGE. The further analysis of S1-PFGE and Southern-blot hybridization confirmed that the bla CTX-M-1 gene in new transconjugants was derived from the inoculated strain. Taken together, high-copper diet facilitates the horizontal transfer and maintenance of the resistant genes in the intestine of rats, although the effects of antibiotics on bacterial resistance appearance and maintenance are more obvious.

Clinical and Bacteriological Analyses of Biofilm-Forming Staphylococci Isolated from Diabetic Foot Ulcers.

Diabetes mellitus is a chronic disease that is associated with increased morbidity and mortality. Unfortunately, foot ulcers and amputations due to diabetes are very common in developing countries. The purpose of this study was to characterize the clinical presentation of diabetic foot ulcer (DFU) infections, isolate the causative agent, and analyze the biofilm formation and distribution of biofilm-related genes among isolated Staphylococci. The study included 100 diabetic patients suffering from DFUs attending Assiut University Hospital. Swabs were collected and antimicrobial susceptibility testing of the isolates was performed. Biofilm formation was tested phenotypically among staphylococcal isolates and the frequency of different biofilm genes was analyzed by PCR. Clinical presentations of diabetic foot ulcers were correlated with bacterial genetic characteristics. Spa types were determined using DNA Gear-a software. Microbiological analysis showed that 94/100 of the DFUs were positive for bacterial growth. The majority of infections were polymicrobial (54%, n=54/100). Staphylococci were the most commonly detected organisms, of which S. aureus represented 37.5% (n=24/64), S. haemolyticus 23.4% (n=15/64), S. epidermidis 34.3% (n=22/64) and other CNS 4.7% (n=3/64). Interestingly, co-infection with more than one species of Staphylococci was observed in 17.1% (n=11/64) of samples. A high level of antibiotic resistance was observed, where 78.1% (n=50/64) of Staphylococci spp were multidrug-resistant (MDR). Phenotypic detection showed that all isolated Staphylococci were biofilm-formers with different grades. Analysis of biofilm-forming genes among Staphylococci showed that the most predominant genes were icaD, spa, and bap. Isolates with a higher number of biofilm-related genes were associated with strong biofilm formation. Sequencing of the spa gene in S. aureus showed that our isolates represent a collection of 17 different spa types. The majority of DFUs in our hospital are polymicrobial. Staphylococci other than S.aureus are major contributors to infected DFUs. MDR and biofilm formation are marked among isolates, which is paralleled by the presence of different categories of virulence-related genes. All severely infected wounds were associated with either strong or intermediate biofilm formers. The severity of DFU is directly related to the number of biofilm genes.

Study on anti-biofilm activity of some commonly available plant leaf extracts on Pseudomonas species and Staphylococcus aureus

Bacteria benefit from biofilm formation because it shields them from unfavorable circumstances. Compared to planktonic bacteria, it demonstrates a high level of antibiotic resistance. Additionally, this makes it challenging to manage the associated illnesses. Therefore, the creation of novel anti-biofilm agents is required. Compared to their chemically manufactured counterparts, antimicrobial compounds found in plants are the greatest source because they have few or no negative effects. Plant products are superior in their utility since there is less chance of development of medication resistance and there are less adverse effects. The present work is done to screen anti-biofilm activity of some commonly available plants viz. Tinospora cordifolia, Ocimum basilicum, Justicia adhatoda and Nyctanthes arbortristis on Pseudomonas sps. and Staphylococcus aureus. Phyto-chemical screening was performed for the obtained extracts. The method involved the administration of methanol extract of the plant leaves obtained by maceration procedure, on Pseudomonas species and Staphylococcus aureus. Pseudomonas species biofilm was inhibited by Tinospora and Nyctanthes arbortristis and Staphylococcus aureus biofilm was inhibited by all the four extracts. The studies revealed that all the plant leaves used here exhibit antibiofilm activity. The minimum inhibitory concentration (MIC), biofilm-inhibitory concentration (BIC) and percentage of biofilm formation inhibition were calculated, Tinospora and Nyctanthes were revealed to be the most efficient plants against both bacteria.