Bacterial Antibiotics Research Articles

Development of a molecularly imprinted membrane for selective, high-sensitive, and on-site detection of antibiotics in waters and drugs: Application for sulfamethoxazole

Sulfonamides are among the widespread bacterial antibiotics. Despite this, their quick emergence constitutes a serious problem for ecosystems and human health. Therefore, there is an increased interest in developing relevant detection method for antibiotics in different matrices. In this work, a straightforward, green, and cost-effective protocol was proposed for the preparation of a selective molecularly imprinted membrane (MIM) of sulfamethoxazole (SMX), a commonly used antibiotic. Thus, cellulose acetate was used as the functional polymer, while polyethylene glycol served as a pore-former. The developed MIM was successfully characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The MIM was used as a sensing platform in conjunction with a smartphone for optical readout, enabling on-site, selective, and highly sensitive detection of SMX. In this way, a satisfactory imprinting factor of around 3.6 and a limit of detection of 2 ng mL−1 were reached after applying response surface methodologies, including Box-Behnken and central composite designs. Besides, MIM demonstrated its applicability for the accurate and selective detection of SMX in river waters, wastewater, and drugs. Additionally, the MIM was shown to be a valuable sorbent in a solid-phase extraction protocol, employing a spin column setup that offered rapid and reproducible results. Furthermore, the developed sensing platform exhibited notable regeneration properties over multiple cycles and long shelf-life in different storage conditions. The newly developed methodology is of crucial importance to overcome the limitations of classical imprinting polymers. Furthermore, the smartphone-based platform was used to surpass the typically expensive and complicated methods of detection.

Topical issues of antibiotic resistance: modern methods of identification of bacterial pathogens and determination of their qualities

One of the most urgent problems in medicine today is the problem of antibiotic resistance. Why this problem? After all, scientists around the world proclaimed victory over microorganisms in the 50-60s of the last century? And since the 70s already began to appear information about resistant strains. Everything turned out to be not so simple. Due to uncontrolled and irrational use of antibiotics, mankind is rapidly approaching the so-called "post-antibiotic era". How to stop this "approach"? It is necessary to clearly follow the principles of rational antibiotic therapy.
 Rational antibiotic therapy requires identifying the bacterial nature of the disease, determining the sensitivity of the microorganisms to the antibiotic and starting treatment as soon as possible. To comply with these principles, rapid and accurate methods of identification of microorganisms are necessary, because it is on the basis of these methods that the most effective antimicrobial agent is selected.
 There are standard methods of identification, which include the disk-diffusion method and the serial dilution method. The main disadvantage of these methods is the length of time it takes to obtain results.
 So what are the alternative methods available? There are many methods of microbial identification, but not all of them are suitable for widespread use due to the high cost, the need for expensive equipment.
 Of all the current methods, three methods are emphasized in this review: 16S rRNA gene sequencing, MALDI-TOF MS and EUCAST RAST. Sequencing of the 16S rRNA gene is based on decoding the region of the gene, which in bacteria carries information on resistance mechanisms and structure features. MALDI-TOF MS is a desorption method of "soft" ionization caused by exposure of the matrix with the analyzed substance to pulses of laser radiation. The EUCAST RAST method is an accelerated disk-diffusion method.
 This review describes the problem of antibiotic resistance, mechanisms of bacterial resistance, as well as modern and standard methods of bacterial identification and antibiotic sensitivity.
 The aim of this review was to compare routine methods of identification of species and qualitative properties of microorganisms, causative agents of nosocomial infections, with modern technologies of microbiological testing as an important step in solving the problem of priority selection of effective antimicrobial agents.
 So, the main question of this review is: can modern methods displace standard methods of microorganism identification?

Antimicrobial resistance of clinical bacterial isolates according to the WHO’s AWaRe and the ECDC-MDR classifications: the pattern in Ghana’s Bono East Region

IntroductionAntimicrobial resistance (AMR) remains a significant health challenge globally and nations have the responsibility to maintain a constant surveillance of AMR, particularly for the emergence of multidrug-resistant (MDR) isolates to existing antibiotics. Against this backdrop, we applied the WHO’s AWaRe (ACCESS, WATCH, and RESERVE) antibiotics classification and the European Centre for Disease Prevention and Control (ECDC)’s multidrug resistance definition for AMR isolates from clinical specimens.MethodThis study reviewed bacterial culture and antibiotic sensitivity test outcomes. These results were then grouped according to the AWaRe and ECDC-MDR classifications.ResultsIn all, the culture and sensitivity results of the 3,178 clinical specimens were investigated, of which 59.5% were from female patients. The pathogens were isolated from 1,187 specimens (37.4%). The WHO’s ACCESS antibiotics, tetracycline, showed a relatively high level of insusceptibility, particularly among Gram-positive (GP) isolates (ranging from 66.7% to 76.7%), along with augmentin (ranging from 44.7% to 81.3%) and cloxacillin (ranging from 50.0% to 78.1%). However, the Gram-negative (GN) isolates showed a relatively high level of susceptibility to amikacin, augmentin, and nitrofurantoin. The WHO’s WATCH antibiotics, cefuroxime, ceftriaxone, cefotaxime, and ciprofloxacin showed a relatively high level of non-responsiveness among the GN isolates, particularly Proteus (ranging from 31.4% to 78.4%), Pseudomonas (ranging from 21.4% to 96.4%), and Enterobacter (ranging from 62.5% to 100%) spp. Among the WHO’s RESERVE antibiotics, resistance to ceftazidime was commonly associated with the GN coliform isolates: Eschericha coli, Klebsiella, and Citrobacter spp. Insusceptibility to meropenem was frequently observed in Staphylococcus spp., E. coli, coliforms, and Proteus spp. Out of the 1,187 isolates, 15.5% (184) were GAT (gentamycin, ampicillin, and tetracycline) MDR, of which 61% (112/184) were from specimens of female patients. The most predominant GAT-MDR isolates were Staphylococcus spp., E. coli, coliforms, and Klebsiella spp.ConclusionIn conclusion, the study revealed a relatively high level and diverse range of AMR. However, MDR in accordance with the ECDC definition was relatively low. There is, therefore, a need to have further research on AMR to inform national criteria for MDR in Ghana.

Aerobic Bacterial Profile of Sepsis and Its Antibiotic Susceptibility Pattern Among Patients in a Rural Tertiary Care Center.

Background Bloodstream infections (BSI) are one of the most life-threatening infections associated with high morbidity and mortality. Early diagnosis with appropriate and timely treatment improves the patient outcome. The recent surge in multidrug-resistant (MDR) strains is a matter of concern. This study aims to determine the bacterial etiology and antibiotic sensitivity pattern in BSI among different age groups. Materials and methods The microbiological data of blood culture and sensitivity between April 2019 and April 2021 were extracted from the laboratory recordsand analyzed for the bacterial profile and antibiotic sensitivity pattern. Results Out of the total 3893 blood cultures received during the study period from April 2019 to April 2021, 194 pathogens were isolated, accounting for a prevalence of 4.98%. Among 194 patients with culture-proven BSI, 54.12% (105/194) were adults, and 45.87% (89/194) were children. Of these 194 bacterial isolates, 58.76% (114/194) were gram-negative bacteria, and 41.24% (80/194) were gram-positive bacteria. With regard to the bacteria isolated,Enterococcusspecies with 23.71% (46/194) andAcinetobacterspecies with 22.16% (43/194) were the most common bacteria. The prevalence of MDR was 59.27% (115/194). Notable MDR types were methicillin-resistantStaphylococcus aureus(MRSA) in 15/22 (68.2%) and extended-spectrum beta-lactamase (ESBL) producers in 15/48 (31.25%) cases. Conclusion There is a significant geographical diversity of bacteria causing sepsis and their antibiotic susceptibility pattern. Recent trends showthat multidrug-resistant gram-negative bacilli are the predominant isolates causing BSI. Increased antibiotic resistance is leading to treatment failure and poor clinical outcomes. Hence, there is a need to monitor antibiotic resistance among patients with BSI.

Bacterial patterns and antibiotics sensitivity in culture tests of diabetic foot ulcer

Bacterial patterns and antibiotics sensitivity in culture tests of diabetic foot ulcer

Evaluation of bacterial coinfections and susceptible antibiotic profiles in hospitalized COVID-19 patients in Koya district, Iraq.

Bacterial coinfection among intensive care unit (ICU) COVID-19 patients is not widely studied in Iraq. Hence, the current study was performed to determine the prevalence of secondary bacterial infection and susceptible profile in ICU patients with COVID-19 infections. The study was conducted from November 2021 to April 2022, in Mad Center/ Shahid Doctor Khalid Hospital/Koya district. The midstream urine (MSU), sputum, and throat swab (TS) were obtained. Age, gender, clinical characteristics, bacterial identities, and antibiotic sensitivity profiles were collected for 200 COVID-19 patients. The standard biochemical tests confirmed the bacterial isolates. Antibiotic susceptibility was implemented by using the disk diffusion method. Out of 200 ICU patients, 87 (43.5%) of them had bacterial coinfection. The most predominant bacteria were isolated Acinetobacter baumannii (25.3%), Escherichia coli (18.3%), Pseudomonas aeruginosa (16%), Klebsiella pneumonia (11.5%), followed by Staphylococcus aureus (4.6%), and Enterococcus spp. (3.5%). Gram-negative bacteria showed a high level of sensitivity to Ertapenem (90.7%) and Piperacillin/Tazobactam (84.9%). Gram-positive isolates showed high sensitivity to Teicoplanin (77.2%) and Rifampicin (71%). The susceptibility rate of the isolated bacteria is moderate; this indicates that early diagnosis of coinfections and more accurate use of antibiotics are necessary to mitigate the severity of COVID-19.

Genome-Wide Association Studies (GWAS) Approaches for the Detection of Genetic Variants Associated with Antibiotic Resistance: A Systematic Review.

Antibiotic resistance is a significant threat to public health worldwide. Genome-wide association studies (GWAS) have emerged as a powerful tool to identify genetic variants associated with this antibiotic resistance. By analyzing large datasets of bacterial genomes, GWAS can provide valuable insights into the resistance mechanisms and facilitate the discovery of new drug targets. The present study aimed to undertake a systematic review of different GWAS approaches used for detecting genetic variants associated with antibiotic resistance. We comprehensively searched the PubMed and Scopus databases to identify relevant studies published from 2013 to February 2023. A total of 40 studies met our inclusion criteria. These studies explored a wide range of bacterial species, antibiotics, and study designs. Notably, most of the studies were centered around human pathogens such as Mycobacterium tuberculosis, Escherichia coli, Neisseria gonorrhoeae, and Staphylococcus aureus. The review seeks to explore the several GWAS approaches utilized to investigate the genetic mechanisms associated with antibiotic resistance. Furthermore, it examines the contributions of GWAS approaches in identifying resistance-associated genetic variants through binary and continuous phenotypes. Overall, GWAS holds great potential to enhance our understanding of bacterial resistance and improve strategies to combat infectious diseases.

Use of Transcriptional Signatures to Differentiate Pathogen-Specific and Treatment-Specific Host Responses in Patients With Bacterial Bloodstream Infections.

Clinical outcomes in bacterial bloodstream infections (BSIs) are influenced by bacterial species, host immunity, and antibiotic therapy. The mechanisms by which such factors influence outcomes are poorly understood. We aimed to identify bacterial- and antibiotic-specific host transcriptional signatures in patients with bacterial BSI. RNA sequencing was performed on blood samples from patients with BSI due to gram-negative (GN) versus gram-positive (GP) pathogens: Escherichia coli (n = 30) or Klebsiella pneumoniae (n = 28) versus methicillin-susceptible Staphylococcus aureus (MSSA) (n = 24) or methicillin-resistant S. aureus (MRSA) (n = 58). Patients were matched by age, sex, and race. No significant host transcriptome differences were detected in patients with E. coli versus K. pneumoniae BSI, so these were considered together as GN BSI. Relative to S. aureus BSI, patients with GN BSI had increased activation of the classic complement system. However, the most significant signal was a reduction in host transcriptional signatures involving mitochondrial energy transduction and oxidative burst in MRSA versus MSSA. This attenuated host transcriptional signature remained after controlling for antibiotic therapy. Given the importance of immune cellular energetics and reactive oxygen species in eliminating hematogenous or intracellular MRSA, these findings may offer insights into its persistence relative to other bacterial BSIs.

Profile of Carbapenem Resistant Gram Negative Bacilli in Grha Kedoya Hospital Jakarta

Carbapenems are beta-lactam antibiotics included in the 3rd line of antibiotics, which are the last choice in therapy to overcome various bacterial infections. The more use of antibiotics that are not in accordance with the clinical situation, the more cases of carbapenem resistance found in the hospital. This study aims to analyze gram-negative bacteria, which are resistant to carbapenem antibiotics, in Grha Kedoya Hospital from January to March 2022 using an observational analytical research design for bacterial identification and antibiotic sensitivity testing using colorimetric and turbidimetric methods with a cross-sectional research design. The examination material was all samples infected with Gram-negative bacteria, as many as 174 samples. The data analysis used in this study was descriptive crosstabs. The results stated that there were carbapenem-resistant bacteria in as many as 32 samples (18.4%); the most carbapenem-resistant bacteria were Acinetobacter baumannii bacteria in as many as 16 patients (50%); Pseudomonas aeruginosa and Klebsiella pneumoniae in as many as 8 patients (25%); and the resistance test showed 100% resistance to the antibiotics Doripenem, Imipenem, Meropenem, and Ertapenem.

Six-year analysis of key monitoring for bacterial strain distribution and antibiotic sensitivity in a hospital.

With the widespread use of antimicrobial drugs, bacterial resistance has become a significant problem, posing a serious threat to public health. The prevalence of clinical infection strains in hospitals and their drug sensitivities are key to the appropriate use of antibiotics in clinical practice. To identify prevalent bacteria and their antibiotic resistance profiles in a hospital setting, thereby guiding effective antibiotic usage by clinicians. Specimens from across the institution were collected by the microbiology laboratory. The VITEK 2 compact fully automatic analyzer was used for bacterial identification and antibiotic sensitivity testing, and the WHONET5.6 software was utilized for statistical analysis. A total of 12062 bacterial strains of key monitoring significance were detected. Staphylococcus aureus demonstrated widespread resistance to penicillin, but none of the strains were resistant to vancomycin or linezolid. Moreover, 219 strains of methicillin-resistant coagulase-negative staphylococci and 110 strains of methicillin-resistant Staphylococcus aureus were detected. Enterococcus faecalis showed moderate resistance to the third-generation quinolones ciprofloxacin and levofloxacin, but its resistance to nitrofurantoin and tetracycline was low. Enterococcus faecium displayed significantly lower resistance to third- and fourth-generation quinolones than Enterococcus faecalis. The resistance of two key monitoring strains, Escherichia coli and Klebsiella pneumoniae, to piperacillin/tazobactam was 5%-8%. However, none of the Escherichia coli and Klebsiella pneumoniae strains were resistant to meropenem. The resistance of Acinetobacter baumannii to piperacillin/sulbactam was nearly 90%. Nonetheless, the resistance to tigecycline was low, and Pseudomonas aeruginosa demonstrated minimal resistance in the antibiotic sensitivity test, maintaining a resistance of < 10% to the cephalosporin antibiotics cefotetan and cefoperazone over the last 6 years. The resistance to amikacin remained at 0.2% over the past 3 years. Our hospital's overall antibiotic resistance rate was relatively stable from 2017 to 2022. The detection rates of key monitoring strains are reported quarterly and their resistance dynamics are monitored and communicated to the entire hospital, which can guide clinical antibiotic selection.

Bacteriology of Adenoids and Tonsils in Children With Recurrent Adenotonsillitis.

Recurrent adenotonsillitis (AT) commonly affects children and may be associated with various complications. Infections are common etiology, and microbial profiles may vary widely in different cases. In this study, we evaluated the bacterial profile and antibiotic sensitivity of pathogens identified in tonsil and adenoid core cultures in children with recurrent AT. In this cross-sectional, observational study, culture and antibiotic sensitivity were performed from tonsil and adenoid core samples obtained after adenotonsillectomy of children (5 to 18 years) with recurrent AT. Children who had received antibiotics within one week before surgery were excluded. Drug sensitivity was performed only for drugs available on the hospital panel list. Bacterial growth was observed in 83 (91.2%) tonsil core cultures (n=91) and 43 (79.6%) adenoid core cultures (n=54). In the tonsil and adenoid core cultures, poly-microbial growth was seen in 25 (27.0%) and 11 (25.6%) children, respectively. From the tonsil core cultures, the majority of the bacteria were sensitive to ciprofloxacin, ampicillin, piperacillin-tazobactam, cefoperazone-sulbactam, ceftazidime, cefotaxime, levofloxacin. From the adenoid core culture, the majority of the bacteria were sensitive to ciprofloxacin, ampicillin, piperacillin-tazobactam, cefoperazone-sulbactam, cephalexin, and cefotaxime. In recurrent AT, polymicrobial growth is not uncommon in both tonsil and adenoid core cultures. Identifying the correct pathogens and their antibiotic sensitivity patterns can help plan treatment strategies for the effective management of recurrent AT.

Bacteriophage Therapy Against Antimicrobial Resistant Crisis

The most common virus on the earth is bacteriophage (or phages) that are present in all organisms. Their classification is currently being evaluated based on the phage's unique and antibacterial properties. The phage replicates within the host through a lytic or lysogenic process following infection and use of a bacterial cell machine. Phage has become an effective therapeutic drug against pathogens after twort and Filex d'Herelle discovery of bacteriophage in the 1900s, and subsequent research has been conducted. Nevertheless, bacteriophage therapy has become an unavoidable option for research due to the recent occurrence of bacterial antibiotics resistance. Around fifty years after antibiotic were found, antibiotics resistance is key risk for health care. Antimicrobial resistance is a rising big issue in global healthcare. The WHO, 1st report on antimicrobial resistances globally, has emphasized the threat of a forthcoming post antibiotics age, where little infection could be not treatable and once again will be fatal. Considering the present condition, producing therapeutic agent that are complementary to antibiotics play great role to fight against antibiotic resistance. The crisis requires development and implementation of new therapeutic agents against infections and phage therapy is suitable to control infectious diseases because safety of phage therapy. There is a perception with regards to phage therapy that phages are usually safe, on the bases of fact that they are ubiquitous in nature and our continued contact to phages in the environment and furthermore that they are widely used without adverse effects in many of the world. with this positive interpretation, the application of phage therapy must be verified by current research studies. bacteriophage preparations contain detrimental substances, such as toxins of gram-negative bacteria, during the formulation process of bacteriophage and that can be remove by different purification methods. Phages effects normal flora GIT negligibly due to specificity in nature and they infect only a small number of bacterial species.

Co-exposure of chromium or cadmium and a low concentration of amoxicillin are responsible to emerge amoxicillin resistant Staphylococcus aureus

Heavy metals and antimicrobials co-exist in many environmental settings. The co-exposure of heavy metals and antimicrobials can drive emergence of antimicrobial resistant (AMR) Enterobacteriaceae. We hypothesized that co-exposure to heavy metals and a low concentration of antibiotic might alter antimicrobial susceptibility patterns, which facilitate emergence of AMR Staphylococcus aureus. The growth kinetics of antimicrobial susceptibleS. aureuswas carried out in the presence of chromium or cadmium salt and a low concentration of antibiotics. Subsequently, the antimicrobial susceptibility pattern was determined by the Kirby-Bauer disc diffusion method.Moreover, the mRNA copy number was determined by reverse transcription polymerase chain reaction. The antimicrobial susceptibility profile revealed that the zone of inhibition (ZOI) for ampicillin, amoxicillin, ciprofloxacin and doxycycline was significantly decreased in chromium pre-exposed S. aureuscompared to unexposed bacteria, whereas cadmium pre-exposed bacteria only showed significant decreased in ZOI for amoxicillin. Moreover, the MIC of amoxicillin for S. aureus was increased by 8-fold in chromium and 32-fold in cadmium when bacteria were co-exposed with low concentrations of amoxicillin. The mRNA expression of femX, mepA and norA also significantly increased in S. aureus after exposure tochromium and a low concentration of amoxicillin. Cultivation of S. aureus at the minimum levels of chromium or cadmium and a low concentration of amoxicillin increased the inhibitory concentration of amoxicillin through inducing bacterial efflux pumps and antibiotic resistant genes. However, it is warranted to assess the whole transcriptome to find out all responsible factors behind this de novo amoxicillin resistant S. aureus.

A Study of Spontaneous Bacterial Peritonitis in Cirrhosis of Liver with Ascites at a Tertiary Care Hospital in North India: Prevalence, Clinical, and Microbiological Profile

Background and Objectives: In patients with chronic liver disease and ascites, spontaneous bacterial peritonitis (SBP) is a common complication. This can progress gradually and subtly or go undiagnosed until signs start to show. Early diagnosis is essential for effective treatment and the prevention of subsequent episodes because the mortality rate following a single episode varies from 20% to 40%. The goal was to study the incidence, clinical profile, and microbiological characteristics of SBP and its variants in people with liver cirrhosis and ascites. Materials and Methods: This observational study was done on 104 cirrhotic patients with ascites admitted at a tertiary care hospital. Basic demographics, symptoms, and clinical signs of patients were recorded. Diagnostic paracentesis was done aseptically and immediately sent for ascitic fluid cytology, biochemistry, and culture. Bacterial examination and antibiotic sensitivity tests were carried out by standard microbiological techniques. Results: Out of a total of 104 cirrhotic patients, 28 (26.9%) were diagnosed with SBP. Alcohol was the most common etiological factor, followed by hepatitis C infection. Among the SBP patients, the most common presentation was culture-negative neutrocytic ascites (71.4%), followed by classical SBP (17.8%), then mono bacterial non neutrocytic bacterascites MNB (10.7%). Among the symptoms, the most common was abdominal distension, followed by icterus, pedal edema, and abdominal pain. Majority of the patients belonged to Child–Pugh’s Grade C. Of 28 cases of SBP, 8 were culture positive. Gram-negative isolates were predominant (75%) and Escherichia coli were the most common isolate. Interpretation and Conclusion: The prevalence of SBP in cirrhotic patients was 26.9%, and Gram-negative isolates were predominant. Ascitic fluid culture and susceptibility testing can lead to accurate diagnosis of SBP and can guide for treatment as resistance to antibiotics is common.

Potential use of garlic products in ruminant feeding: A review.

The addition of antibiotics as growth promoters to ruminant feed can result in bacterial resistance and antibiotic residues in ruminant products. Correspondingly, there is serious public concern regarding the presence of antibiotic residue in ruminant products and the consequent threat to human health. As a result, the addition of plants and their products to ruminant feeds, as an alternative to antibiotics, has received much attention recently. Garlic and its products are rich in organosulphur compounds, which have a variety of biological activities and have been widely used as natural additives in animal production. This review presents recent knowledge on the addition of garlic products (powder, skin, oil, leaf and extracts) to the diets of ruminants. In this paper, garlic products are evaluated with respect to their chemical composition, bioactive compounds, and their impacts on the rumen ecosystem, antioxidant status, immune response, parasitic infection, growth performance and product quality of ruminants. This review provides valuable guidance and a theoretical basis for the development of garlic products as green, highly efficient and safe additives, with the aims of promoting ruminant growth and health, reducing methane emissions and improving ruminant product quality. Garlic extracts have the potential to control parasite infections by decreasing the faecal egg count. Garlic powder, oil and allicin are able to reduce the methane emissions of ruminants. Organosulphur compounds such as allicin, which is present in garlic products, have the potential to inhibit membrane lipid synthesis of the archaeal community, thus influencing the population of methanogenic archaea and resulting in a reduction in methane emissions. Some garlic products are also able to increase the average daily gain (garlic skin, water extract, and leaf) and the feed conversion ratio (garlic skin and leaf) of ruminants. Garlic stalk silage fed to sheep has the potential to improve the nutritional value of mutton by increasing the concentrations of linoleic and linolenic acids and essential amino acids. Sheep fed a diet containing garlic powder or oil are able to produce milk with higher concentrations of the conjugated linoleic acids and n-3 fatty acids, which has health benefits for consumers, due to the widely recognized positive impact of n-3 polyunsaturated fatty acids and conjugated linoleic acids on human heart health, improving platelet aggregation, vasodilation and thrombotic tendency. Overall, garlic products have the potential to enhance growth performance and product quality and reduce parasite infections, as well as methane emissions of ruminants.

Distribution and antimicrobial sensitivity pattern of multidrug-resistant Pseudomonas aeruginosa from the clinical specimen in Aceh, Indonesia

The development of P. aeruginosa resistance to antibiotics is increasing globally due to the inappropriate use of antibiotics. This retrospective descriptive study aimed to determine the distribution of multidrug resistant P. aeruginosa (MDRPA) and its antimicrobial sensitivity profiles. Data were taken from the bacterial identification and antibiotic sensitivity testing of clinical specimens in Aceh Provincial Referral Hospital from July 2017 to June 2019, where the VITEK® 2 Compact automatic device was used for the identification. In total, there were 307 P. aeruginosa isolates analyzed in this study. The results of this study revealed that 54.39% of P. aeruginosa isolates were multidrug resistant. The MDRPA were mostly found in sputum and pus cultures (41.91% and 23.95%, respectively). Based on the wardroom as the source, most samples came from the internal medicine unit, intensive care unit, and surgical unit with prevalence of 27.54%, 25.74%, and 20.35%, respectively. High proportion of infected patients were male (52.09%) and aged 56–65 years (23.95%). P. aeruginosa showed the highest sensitivity rate to amikacin (77.1%), followed by meropenem (74.4%), ceftazidime (70.1%), levofloxacin (65.1%), tobramycin (64.9%), piperacillin-tazobactam (64.3%), and gentamicin (61.4%). In conclusion, our data suggest that the MDRPA infection is prevalent in Aceh Province and Amikacin is recommended as the highest standard of therapy for MDRPA.

Contamination of long-term manure-fertilized Indian paddy soils with veterinary antibiotics: Impact on bacterial communities and antibiotics resistance genes

In the present study, we investigated the implication of long-term fertilization of Indian rice paddies with animal manures on the prevalence of veterinary antibiotics (VAs) residues, enrichment of soil microorganisms, and abundance of antibiotic resistance genes (ARGs). The most frequently detected antibiotics in Indian paddy soils were tetracyclines followed by sulfonamides. The soils long-term fertilized with poultry manure (PM) and cow manure (CM) contained significant amounts of VAs (137.20 μg kg−1) in soil. Members of Actinobacteria, Streptomyces, Rubrobacter, Pseudonocardia, Pseudomonas and Rhizobium were predominant in soils that received PM or CM. ARGs such as mtrA, arlR, bcrA, novA, oleC, sul4 and kdpE that confer resistance mostly to macrolides, aminocoumarins, multi-drugs, and sulfonamides were predominant, and the main phyla that contributed ARGs included Actinobacteria (55 %) and Proteobacteria (22 %). Antibiotic modification/degradation was the major (58.30 %) antibiotic resistance mechanism in bacteria enriched in long-term fertilized soils. Residues of tetracyclines, quinolones, sulfonamides, Cu and Cd in soils positively correlated with ARGs. Notably, this study is the first evidence on the prevalence of VAs, antibiotic-resistant microbes, and ARGs in paddy soils of India long-term fertilized with PM or CM and shed light on the interactions between antibiotics, heavy metals and ARGs.

Maintenance and generation of proton motive force are both essential for expression of phenotypic antibiotic tolerance in bacteria.

Bacterial antibiotic tolerance, a phenomenon first observed in 1944, is known to be responsible for both onset and exacerbation of recurrent and chronic bacterial infections. The development of antibiotic tolerance was previously thought to be due to a switch to physiological dormancy when bacteria encounter adverse growth conditions. Our recent laboratory findings, however, showed that a set of genes related to the maintenance of proton motive force (PMF) are up-regulated under starvation, indicating that the tolerant sub-population, which are commonly known as persisters, can actively maintain their tolerance phenotypes. In this study, we investigated the relative functional roles of proteins involved in the maintenance and active generation of PMF in mediating tolerance formation in bacteria and found that the PspA and RcsB proteins play a key role in PMF maintenance in persisters, as deletion of genes encoding these two proteins resulted in significantly lower tolerance levels. Consistently, expression of the OsmC and Bdm proteins, which is under regulation by RcsB, is required to maintain PMF and the antibiotic tolerance phenotypes. On the other hand, the NuoL, Ndh, AppC, CyoB, and NuoF proteins, which are electron transport chain (ETC) components, were also found to be actively expressed in persisters in order to generate PMF to support functioning of various tolerance mechanisms such as efflux activities. Our data show that active generation of PMF is even more important than the PMF maintenance functions of PspA and RcsB in the expression of antibiotic tolerance phenotypes in persisters. Assessment of double- and triple-gene knockout strains, in which the PMF maintenance genes and those encoding ETC components were simultaneously deleted, confirms that these two groups of genes are both required for the expression of antibiotic tolerance phenotypes and that a lack of these functions would result in complete PMF dissipation and accumulation of antibiotics in the intracellular compartment of persisters and eventually cell death. Products of these genes are, therefore, ideal targets for future development of anti-tolerance agents. IMPORTANCE In this work, bacteria were found to undergo active generation and maintenance of proton motive force (PMF) under adverse conditions, such as starvation so as to support a range of physiological functions in order to survive under such conditions for a prolonged period. The ability to maintain a substantial level of PMF was found to be directly linked to that exhibiting phenotypic antibiotic tolerance under nutrient starvation or other adverse conditions. These findings infer that bacteria do not simply become physiologically dormant when they become antibiotic tolerant, instead they need to produce a wide range of proteins including those which help prevent PMF dissipation, such as PspA and RcsB, and the electron transport chain components, such as NuoL and Ndh, that actively generate PMF even during long-term starvation. As antibiotic tolerant sub-population is known to play a role in eliciting recurrent and chronic infections, especially among patients with a weakened immune system, the PMF maintenance mechanisms identified in this work are potential targets for the development of new strategies to control recurrent and chronic infections.

Reduced bacterial resistance antibiotics with improved microbiota tolerance in human intestinal: Molecular design and mechanism analysis

Antibiotic selectivity and bacterial resistance are critical global public health issues. We constructed a multi-class machine learning model to study antibiotic effects on human intestinal microbiota abundance and identified key features. Binding energies of β-lactam antibiotics with Escherichia coli PBP3 mutant protein were calculated, and a 2D-QSAR model for bacterial resistance was established. Sensitivity analysis identified key features affecting bacterial resistance. By coupling key features from the machine learning model and 2D-QSAR model, we designed ten flucloxacillin (FLU) substitutes that improved intestinal microbiota tolerance and reduced antibiotic bacterial resistance. Concurrently, the substitutes exhibited superior degradability in soil, aquatic environments, and under photolytic conditions, coupled with a reduced environmental toxicity compared to the FLU. Evaluations under combined medication revealed significant improvements in functionality and bacterial resistance for 80% of FLU substitutes, with 50% showing more than a twofold increase. Mechanistic analysis demonstrated enhanced binding to target proteins and increased biodegradability for FLU substitutes due to more concentrated surface charges. Reduced solvent hindrance and increased cell membrane permeability of FLU substitutes, mainly due to enhanced interactions with phospholipid bilayers, contributed to their functional selectivity. This study aims to address poor antibiotic selectivity and strong bacterial resistance, providing guidance for designing antibiotic substitutes.

Chlorine disinfection modifies the microbiome, resistome and mobilome of hospital wastewater – A nanopore long-read metagenomic approach

The aim of the present study was to analyze changes in the microbiome, resistome, and mobilome of hospital wastewater (HWW) induced by disinfection with chlorine compounds. Changes in bacterial communities and specific antibiotic resistance genes (ARGs) in HWW were determined with the use of a nanopore long-read metagenomic approach. The main hosts of ARGs in HWW were identified, and the mobility of resistance mechanisms was analyzed. Special attention was paid to the prevalence of critical-priority pathogens in the HWW microbiome, which pose the greatest threat to human health. The results of this study indicate that chlorine disinfection of HWW can induce significant changes in the structure of the total bacterial population and antibiotic resistant bacteria (ARB) communities, and that it can modify the resistome and mobilome of HWW. Disinfection favored the selection of ARGs, decreased their prevalence in HWW, while increasing their diversity. The mobility of the HWW resistome increased after disinfection. Disinfection led to the emergence of new drug resistance mechanisms in previously sensitive bacterial taxa. In conclusion, this study demonstrated that HWW disinfected with low (sublethal) concentrations of free chlorine significantly contributes to the mobility and transfer of drug resistance mechanisms (including critical mechanisms) between bacteria (including pathogens).