Spread Of Drug-resistant Bacteria Research Articles

Evaluation the kill rate and mutant selection window of danofloxacin against Actinobacillus pleuropneumoniae in a peristaltic pump model

BackgroundActinobacillus pleuropneumoniae is a serious pathogen in pigs. The abundant application of antibiotics has resulted in the gradual emergence of drugresistant bacteria, which has seriously affected treatment of disease. To aid measures to prevent the emergence and spread of drug-resistant bacteria, herein, the kill rate and mutant selection window (MSW) of danofloxacin (DAN) against A. pleuropneumoniae were evaluated.MethodsFor the kill rate study, the minimum inhibitory concentration (MIC) was tested using the micro dilution broth method and time-killing curves of DAN against A. pleuropneumoniae grown in tryptic soy broth (TSB) at a series drug concentrations (from 0 to 64 MIC) were constructed. The relationships between the kill rate and drug concentrations were analyzed using a Sigmoid Emax model during different time periods. For the MSW study, the MIC99 (the lowest concentration that inhibited the growth of the bacteria by ≥ 99%) and mutant prevention concentration (MPC) of DAN against A. pleuropneumoniae were measured using the agar plate method. Then, a peristaltic pump infection model was established to simulate the dynamic changes of DAN concentrations in pig lungs. The changes in number and sensitivity of A. pleuropneumoniae were measured. The relationships between pharmacokinetic/pharmacodynamic parameters and the antibacterial effect were analyzed using the Sigmoid Emax model.ResultsIn kill rate study, the MIC of DAN against A. pleuropneumoniae was 0.016 µg/mL. According to the kill rate, DAN exhibited concentration-dependent antibacterial activity against A. pleuropneumoniae. A bactericidal effect was observed when the DAN concentration reached 4–8 MIC. The kill rate increased constantly with the increase in DAN concentration, with a maximum value of 3.23 Log10 colony forming units (CFU)/mL/h during the 0–1 h period. When the drug concentration was in the middle part of the MSW, drugresistant bacteria might be induced. Therefore, the dosage should be avoided to produce a mean value of AUC24h/MIC99 (between 31.29 and 62.59 h. The values of AUC24h/MIC99 to achieve bacteriostatic, bactericidal, and eradication effects were 9.46, 25.14, and > 62.59 h, respectively.ConclusionThese kill rate and MSW results will provide valuable guidance for the use of DAN to treat A. pleuropneumoniae infections.

Frequency of drug-resistant bacterial isolates among pregnant women with UTI in maternity and children’s hospital, Bisha, Saudi Arabia

Urinary tract infections (UTIs) are one of the most prevalent bacterial infections affecting humans, with a higher incidence among women. Pregnant women are at an increased risk of developing UTIs, which can have detrimental consequences for both the mother and fetus. UTIs can be caused by various bacteria, and the prevalence of drug-resistant UTIs in maternity and children’s hospitals is a cause for concern due to the potential for severe complications if left untreated. The primary objective of the current study was to determine the distribution of UTI-causing bacteria and investigate the antibiotic sensitivity patterns of isolated cultures obtained from pregnant women with UTIs at the Maternity and Children’s Hospital, Bisha, Saudi Arabia. This cross-sectional study was conducted from October 2021 to October 2023, involving the analysis of urine samples collected from 321 participants who acquired UTIs during pregnancy. Using biochemical tests and standard cultures, the urine samples were examined for pathogenic bacteria and their anti-microbial sensitivity patterns. The study analyzed susceptibility results according to the Clinical Laboratory Standards Institute guidelines (M100, 28th Edition, 2018). Bacterial strains demonstrating resistance to three or more antibiotics were classified as multidrug-resistant (MDR). This study revealed the distribution of UTI-causing bacteria to be as follows: Escherichia coli, 57.01%; Klebsiella pneumoniae, 24.61%; Pseudomonas aeruginosa, 4.36%; Proteus mirabilis and Enterobacter cloacae, 3.74%; Streptococcus agalactiae, 3.11%; Enterococcus faecalis, 2.18%; and Staphylococcus aureus, 1.24%. Antimicrobial susceptibility testing varied among gram-positive and gram-negative bacteria. Gentamicin demonstrated the highest sensitivity among both gram-positive and gram-negative bacteria; piperacillin-tazobactam was the second most effective drug against gram-negative bacteria. The bacterial isolates showed varying susceptibility to different antibiotics, with Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa being mainly sensitive to gentamicin, piperacillin-tazobactam, and ciprofloxacin, respectively. The strategies for reducing the risk of UTIs need to be improved to limit the spread of MDR bacteria. These strategies may include promoting hygienic practices and administering appropriate antibiotics to prevent the emergence and spread of drug-resistant bacteria. Further research is required to monitor the trends in antibiotic resistance among UTI-causing bacteria and develop effective strategies for managing this public health menace.

Molecular Characterization of Escherichia coli Causing Urinary Tract Infections Through Next-Generation Sequencing: A Comprehensive Analysis of Serotypes, Sequence Types, and Antimicrobial and Virulence Genes.

Introduction An enormous increase in antimicrobial resistance (AMR) among bacteria isolated from human clinical specimens contributed to treatment failures. Increased surveillance through next-generation sequencing (NGS) or whole genome sequencing (WGS) could facilitate the study of the epidemiology of drug-resistant bacterial strains, resistance genes, and other virulence determinants they are potentially carrying. Methods This study included 30 Escherichia coli (E. coli) isolates obtained from patients suffering from urinary tract infections (UTIs) attending Prathima Institute of Medical Sciences, Karimnagar, India. All bacterial isolates were identified, and antimicrobial susceptibility patterns were determined through conventional microbiological techniques and confirmed by automated systems. All the isolates were investigated using NGS to identify genes coding for resistance, such as extended-spectrum beta-lactamases (ESBLs), metallo-beta-lactamases, and virulence genes. Multilocus sequence typing (MLST) was used to understand the prevalent strain types, and serotyping was carried out to evaluate the type of O (cell wall antigen) and H (flagellar antigen) serotypes carried by the isolates. Results The conventional antimicrobial susceptibility testing revealed that 15 (50%) isolates were resistant to imipenem (IPM), 10 (33.33%) were resistant to amikacin (AK), 13 (43.33%) were resistant to piperacillin-tazobactam (PTZ), 17 (56.66%) were resistant to cephalosporins, and 14 (46.66%) were resistant to nitrofurantoin (NIT). Among the isolates, 26 (86.66%) had revealed the presence of multiple antibiotic-resistant genes with evidence of at least one gene coding for beta-lactamase resistance. There was a high prevalence of blaCTX-M(19/30, 63.33%) genes, followed by blaTEMand blaOXA-1. The blaNDM-5 gene was found in three isolates (3/30, 10%). The virulence genes identified in the present study wereiutA, sat, iss, and papC, among others. The E. coli serotype found predominantly belonged to O25:H4 (5, 16.66%), followed by O102:H6 (4, 13.33%). A total of 16 MLST variants were identified among the examined samples. Of the MLST-based sequence types (STs) identified, ST-131 (7, 23.33%) was the predominant one, followed by ST-167 (3, 10%)and ST-12 (3, 10%). Conclusions The study results demonstrated that the E. coli strains isolated from patients suffering from UTIs potentially carried antimicrobial resistanceand virulence genes and belonged to different strain types based on MLST. Careful evaluation of bacterial strains using molecular analyses such as NGS could facilitate an improved understanding of bacterial antibiotic resistance and its virulence potential. This could enable physicians to choose appropriate antimicrobial agents and contribute to better patient management, thereby preventing the emergence and spread of drug-resistant bacteria.

Protocol for surveillance of antimicrobial-resistant bacteria causing community-acquired urinary tract infections in low-income countries.

The spread of drug-resistant bacteria into the community is an urgent threat. In most low-middle-income countries (LMICs) settings, community-acquired infection (CAI) is empirically treated with no data to support the choice of antibiotics, hence contributing to resistance development. Continuous antimicrobial resistance (AMR) data on community-acquired pathogens are needed to draft empirical treatment guidelines, especially for areas with limited culture and susceptibility testing. Despite the importance of addressing antibiotic-resistant pathogens in the community setting, protocols for the surveillance of AMR bacterial infections are lacking in most (LMICs). We present a protocol for surveillance of AMR in LMICs using urinary tract infection (UTI) as a proxy for CAI to enable users to quantify and establish the drivers of AMR bacteria causing UTI. The protocol intends to assist users in designing a sustainable surveillance program for AMR in the community involving children above two years of age and adults presenting to a primary health facility for healthcare. Implementation of the protocol requires initial preparation of the laboratories to be involved, surveillance areas, selection of priority bacteria and antimicrobials to be used, and the design of a coordinated sampling plan. Recruitment should occur continuously in selected health facilities for at least 12 months to observe seasonal trends of AMR. At least 10 mL of clean-catch mid-stream urine must be collected into 20 mL calibrated sterile screw-capped universal bottles lined with 0.2 mg boric acid and transported to the testing laboratory. Utilise the data system that generates standard reports for patient care to be shared internally and externally in the regions and the world through global platforms such as the Global Antimicrobial Resistance Surveillance System.

Colonization with drug-resistant pathogens among patients in long-term care facilities and under home hospice care - a cross-sectional study.

The spread of drug-resistant bacteria is deemed a worldwide threat. Patients in long-term care, including those under palliative care, are exposed to a high risk of colonization and infection with drug-resistant pathogens. This refers primarily to long-term care facilities as opposed to home care. A cross-sectional study was carried out between 1January 2018 - 30 June 2019. The study was approved by the Bioethics Committee at the Medical University of Warsaw (KB/222/2017). The aim of the study was to assess the frequency and type of colonization with drug-resistant pathogens among patients in long-term care facilities and those under home hospice care. An additional aim was evaluation the risk of pathogen transmission according to the type of provided long-term care. The study included 129 participants: 68 patients under the care of 3 long-term care facilities in Warsaw, Poland, 42 patients under home hospice care, and 19 household members of hospice patients. All included participants provided written informed consent. Oropharyngeal and rectal swabs were obtained from all participants for microbiological assessment. Colonization with pathogens was more common in long-term care facilities residents (82.4%)than in at-home hospice patients (42.9%). Risk of colonization was significantly lower in patients staying at home than in long-term care facilities patients (OR 0.16; 95% CI 0.06-0.38). Conclusions. Risk of colonization with drug-resistant pathogens depends on the type of care and is significantly higher in patients staying at long-term care facilities. Systemic measures, such as microbiological screening, are necessary to provide optimal patient care and to ensure epidemiological safety, both to patients and their caregivers.

Evaluation of the mutant selection window of danofloxacin against Actinobacillus pleuropneumoniae in an in vitro dynamic model.

The rapid emergence and widespread spread of multidrug-resistant bacteria is a serious threat to the health of humans and animals. The pharmacokinetic/pharmacodynamic (PK/PD) integration model based on mutant selection window (MSW) theory is an important method to optimize the dosage regimen to prevent the emergence and spread of drug-resistant bacteria. Actinobacillus pleuropneumoniae (AP) is a pathogen that can cause pleuropneumonia in pigs. We employed an in vitro dynamic infection model (DIM) to study the prevention of drug-resistant mutations of danofloxacin against AP. A peristaltic pump was applied to establish an in vitro DIM to simulate the PK of danofloxacin in plasma, and to study the MSW of danofloxacin against AP. A peristaltic-pump in vitro infection model was established to simulate dynamic changes in the danofloxacin concentration in pig plasma. PK and PD data were obtained. Then, the relationship between PK/PD parameters and antibacterial activity was analyzed by the sigmoid Emax model. The area under the curve during 24 h/ the minimum concentration that inhibits colony formation by 99% (AUC24h/MIC99) had the best-fitting relationship with antibacterial activity. The AUC24h/MIC99 values for a bacteriostatic effect, bactericidal effect, and eradication effect were 2.68, 33.67, and 71.58 h, respectively. We hope these results can provide valuable guidance when using danofloxacin to treat AP infection.

Prevalence and genetic characteristics of fosB-positive Staphylococcus aureus in duck farms in Guangdong, China in 2020.

To investigate the epidemiology of fosB-positive Staphylococcus aureus in waterfowl farms in the Pearl River tributaries in Guangdong Province, China in 2020. A total of 63 S. aureus were recovered from 315 samples collected from six duck farms and one goose farm. PFGE, WGS and analysis were performed on 19 fosB-positive S. aureus. The fosfomycin resistance rate of the strains was as high as 52.4% (33/63), and 30.1% (19/63) of the strains carried fosB. Resistance gene prediction results showed that duck farm environment-derived strains contained the oxazolidinone drug resistance gene optrA. All fosB-positive S. aureus were MRSA and most of them were MDR, mainly ST9-t899 and ST164-t899. PFGE showed that fosB-positive S. aureus from humans and ducks could be clustered into the same clade. In addition, core-genome SNP analysis showed that clonal transmission of S. aureus occurred between humans and water. Pan-genome analysis showed that S. aureus had an open pangenome. The fosB gene was located on 2610-2615 bp plasmids, which all contained a broad host-range plasmid replication protein family 13. Small plasmids carrying the fosB gene could be found in different multilocus STs of S. aureus. This study indicated that duck farms in Guangdong, China could be an important reservoir of fosB-positive S. aureus. The spread of drug-resistant bacteria in waterfowl farms requires further monitoring.

Multicenter Antimicrobial Resistance Surveillance of Clinical Isolates from Major Hospitals - China, 2022.

Bacterial resistance surveillance is crucial for monitoring and understanding the trends and spread of drug-resistant bacteria. The number of strains collected in 2022 increased compared to 2021. The top five bacteria, including Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, remained largely unchanged. The detection rate of methicillin-resistant strains continued to decrease. Among clinical Enterobacterales isolates, the resistance rate to carbapenems was generally below 13%, except for Klebsiellaspp., which had a resistance range of 20.4% to 21.9%. Most clinical Enterobacterales isolates were highly susceptible to tigecycline, colistin, and polymyxin B, with resistance rates ranging from 0.1% to 12.6%. The detection rate of meropenem-resistant P. aeruginosa and meropenem-resistant Acinetobacter baumannii showed a decreasing trend for the fourth consecutive year. Multidrug-resistant bacteria remain a significant public health challenge in clinical antimicrobial treatment. To effectively address bacterial resistance, it is essential to enhance both bacterial resistance surveillance and the prudent use of antimicrobial agents.

Enzyme-triggered smart antimicrobial drug release systems against bacterial infections.

The rapid emergence and spread of drug-resistant bacteria, as one of the most pressing public health threats, are declining our arsenal of available antimicrobial drugs. Advanced antimicrobial drug delivery systems that can achieve precise and controlled release of antimicrobial agents in the microenvironment of bacterial infections will retard the development of antimicrobial resistance. A variety of extracellular enzymes are secreted by bacteria to destroy physical integrity of tissue during their invasion of host body, which can be utilized as stimuli to trigger "on-demand" release of antimicrobials. In the past decade, such bacterial enzyme responsive drug release systems have been intensively studied but few review has been released. Herein, we systematically summarize the recent progress of smart antimicrobial drug delivery systems triggered by bacteria secreted enzymes such as lipase, hyaluronidase, protease and antibiotic degrading enzymes. The perspectives and existing key issues of this field will also be discussed to fuel the innovative research and translational application in the future.

Cu(II)@ZIF-8 nanoparticles with dual enzyme-like activity bound to bacteria specifically for efficient and durable bacterial inhibition

The spread of drug-resistant bacteria has significantly reduced the effectiveness of current antibiotics and poses a growing global challenge. Therefore, there is an urgent demand to develop novel antimicrobial strategies to reduce the use of antibiotics and the spread of drug-resistant bacteria. In this work, we constructed a novel Cu(II)@ZIF-8 nanoenzyme material to realize efficient inhibition effect on bacteria. In vitro antibacterial experiments of the composites demonstrated their excellent antibacterial performance against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In particular, the minimum inhibitory concentration (MIC) against S. aureus was only 64 μg/mL, which was four times the antibacterial activity of ZIF-8 NPs. Antibacterial mechanism studies revealed that Cu(II)@ZIF-8 NPs possessed both oxidase-like and peroxidase-like activities and specifically bound to bacterial cell walls. Such properties facilitated the in-situ production of reactive oxygen species within bacteria, greatly increasing the antibacterial activity with minimum damage to normal biological tissues. In vitro biocompatibility experiments revealed that Cu(II)@ZIF-8 NPs had excellent hemocompatibility and cytocompatibility. Therefore, this research provides a new strategy for the design and preparation of novel efficient and safe antibacterial materials in the future.

Հակամանրէային դեղերի նկատմամբ մանրէային կուլտուրաների զգայունության որոշումը և կայունության մեխանիզմների ուսումնասիրությունը միզուղիների վարակների դեպքում

The uncontrolled and irrational use of antimicrobial drugs in hospitals and outpatient settings (including at home) has led to the emergence of resistance mechanisms of bacterial strains. The increase in fluoroquinolone resistance rates in the 2020-2021 study proves the widespread use of antibiotics (in this case, fluoroquinolones) to treat secondary infections of bacterial origin or to prevent their occurrence during the COVID-19 pandemic. Based on the analysis of the data obtained, the use of fluoroquinolones, cephalosporins of III and IV generations, aminoglycosides of II generation for empirical treatment of urinary tract infections without bacteriological study and the results of sensitivity determination to antimicrobial drugs cannot be justified. Targeted and optimized use of antibiotics, as well as quality laboratory diagnosis and active infection control measures, can prevent the emergence and spread of drugresistant bacteria. The results of the study can be used in healthcare facilities to monitor bacterial resistance, to determine infection control strategies, and to develop policies for their use. Control and monitoring of resistant strains through detection of antibiotic resistance mechanisms, as well as extended analysis (according to the data from healthcare facilities, from regions, according to microbial species and stability mechanisms) requires continued research and long-term studies.

Starved of ACTION: A Critical Look at the Antimicrobial Resistance Action Plans of African Countries.

The urgent need for Africa, as a continent, to start galvanizing resources and strengthening its capacity to win the fight against the looming threat of antimicrobial resistance (AMR) was once again brought to the limelight by the recent study on the "Global Burden of Bacterial Antimicrobial Resistance" (The Lancet 2022, 399, 629). According to the study, western sub-Saharan Africa is a super-region for AMR, with overall mortality rates due to and associated with AMR standing at 27.3 and 114.8 per 100 000 people, respectively. Putting this in perspective, if the leaders of this region do not take effective action, Africa will indeed be one of the two worst-affected regions, along with Asia, with the possibility of over 4.1 million people dying annually from AMR by 2050. The development of a National Action Plan, as directed by the World Health Organization, provides an important framework for addressing the complex and multi-faceted nature of the rise and spread of drug-resistant bacteria. This paper reviews the AMR National Action Plans of African countries and calls on the leaders of this region to move from paper to action and to look beyond just the reduction of antibiotic consumption and, as a more comprehensive response to the threat of AMR, focus also on expanding access to safe drinking water, bettering sanitary conditions, maintaining effective leadership at all levels of governance, increasing government spending on healthcare services, and strengthening regulatory oversight.

Travellers' diarrhoea - prevention, trends and role of microbiome

In this review, we present a contemporary look at the management of travellers' diarrhoea (TD), and we discuss the potential role of a microbiome as well as the administration of live microorganisms in order to prevent TD. We performed a comprehensive search using the PubMed and Web of Science databases for the period 2014-2021, looking for original and review articles on travellers' diarrhoea. TD belongs among the most frequent illnesses experienced by travellers. For the most part, it is manifested as an acute yet self limiting condition, and only in a few cases proceeds to a prolonged form. Epidemiological analyses have shown that the majority of TD cases are caused by bacterial infections. In practice, pharmacological therapy is often used in the prevention and treatment of TD, since patients naturally seek preventive measures against the development of its severe course and its impact on planned activities. Bismuth salicylate is a strongly recommended TD prophylaxis but is not available on all European Union markets. Although the antibiotic prophylaxis is not generally recommended in guidelines, some antibiotic or chemotherapeutic agents are accessible over-the-counter in certain countries, and travellers are routinely encouraged to use them preventively. This routine can alter the microbiome of the traveller and promote the spread of drug resistant bacteria in their place of residence. Probiotic administration is considered safe, although the quality of evidence in favour of its prophylactic use in TD is currently low. The challenge for public health authorities is to educate personnel that can directly influence the behaviour of travellers through safe and effective pharmacological alternatives to antibiotics. Manipulation of the gut microbiome using specific probiotic strains can represent a safe and promising intervention.

Antibiotic prescription practice at veterinary pharmaceutical shops and its potential impact on the development of antimicrobial resistance in Moshi, Northern Tanzania

Aim: We aimed to investigate antibiotic prescription practice in veterinary shops and its potential impact on the development of antimicrobial resistance.
 Methods: A correlation cross-sectional study was carried out in Moshi, Tanzania. A convenient sampling method was used to enroll 80 study participants and 80 Veterinary pharmaceutical shops selling antibiotics for cattle. The study questionnaire was administered to both pharmaceutical sellers and cattle keepers Results: A total of 80 veterinary pharmaceutical shops visited to deliver information about antibiotics sold with or without prescription from veterinary professionals and eighty (80) human participants. Most of the study participant 66/80 (82.5%) responded to started treatment before laboratory diagnosis and diagnosis was mainly based on symptoms and signs 58/80 (72.5%); owners description 17/80 (21.3%) and less frequently on none specific reason 15/80 (6.5%) (Χ2=77.89, P= 0.000, OR=0.875, 95% CI= 0.803-0.947). Tetracycline 30 (100%), Trimethoprim/sulfamethoxazole 10 (100%), and amoxicillin/clavulanic acid 7 (100%) were highly sold unprescribed drugs and no quantity of these drugs was prescribed before selling at Veterinary pharmaceutical shops.
 Conclusion: The regulation of Veterinary antibiotic prescription at veterinary pharmaceutical shops has to be a point of discussion and paid greater attention to ensure a sustainable control and reduction of transmission and spread of drug-resistant bacteria in humans and cattle.
 Keywords: antibiotic prescription practice, antimicrobial resistance, Veterinary pharmaceutical shops

Ultrasensitive detection of β-lactamase-associated drug-resistant bacteria using a novel mass-tagged probe-mediated cascaded signal amplification strategy.

The emergence and spread of drug-resistant bacteria (DRB) is a global health threat. Early and accurate detection of DRB is a critical step in the treatment of DRB infection. However, traditional assays for DRB detection are time-consuming and have inferior analytical sensitivity and quantification capability. Herein, a mass-tagged probe (MP-CMSA)-mediated enzyme- and light-assisted cascaded signal amplification strategy was developed for the ultrasensitive detection of β-lactamase (BLA), an enzyme closely associated with most DRB. Each MP-CMSA probe contained multiple poly(amidoamine) (PAMAM) dendrimer molecules immobilized on a streptavidin agarose bead via a BLA-cleavable linker, and each dendrimer was modified with multiple mass tags via a photo-cleavable linker. In BLA detection, BLA could cleave the BLA-cleavable linker, leading to dendrimers shedding from the MP-CMSA probe to achieve enzyme-assisted signal amplification. Then, each dendrimer can further release mass tags under UV light to achieve light-assisted signal amplification. After this cascaded signal amplification, the released mass tags were ultimately quantified by mass spectrometry. Consequently, the sensitivity of BLA detection can be significantly enhanced by four orders of magnitude with a detection limit of 50.0 fM. Finally, this approach was applied to the blood samples from patients with DRB. This platform provides a potential strategy for the sensitive, rapid and quantitative detection of DRB infection.

Helicobacter pylori infection and antibiotic resistance - from biology to clinical implications.

Helicobacter pylori is a major human pathogen for which increasing antibiotic resistance constitutes a serious threat to human health. Molecular mechanisms underlying this resistance have been intensively studied and are discussed in this Review. Three profiles of resistance - single drug resistance, multidrug resistance and heteroresistance - seem to occur, probably with overlapping fundamental mechanisms and clinical implications. The mechanisms that have been most studied are related to mutational changes encoded chromosomally and disrupt the cellular activity of antibiotics through target-mediated mechanisms. Other biological attributes driving drug resistance in H. pylori have been less explored and this could imply more complex physiological changes (such as impaired regulation of drug uptake and/or efflux, or biofilm and coccoid formation) that remain largely elusive. Resistance-related attributes deployed by the pathogen cause treatment failures, diagnostic difficulties and ambiguity in clinical interpretation of therapeutic outcomes. Subsequent to the increasing antibiotic resistance, a substantial drop in H. pylori treatment efficacy has been noted globally. In the absence of an efficient vaccine, enhanced efforts are needed for setting new treatment strategies and for a better understanding of the emergence and spread of drug-resistant bacteria, as well as for improving diagnostic tools that can help optimize current antimicrobial regimens.

Resistance and Adaptation of Bacteria to Non-Antibiotic Antibacterial Agents: Physical Stressors, Nanoparticles, and Bacteriophages.

Antimicrobial resistance is a significant threat to human health worldwide, forcing scientists to explore non-traditional antibacterial agents to support rapid interventions and combat the emergence and spread of drug resistant bacteria. Many new antibiotic-free approaches are being developed while the old ones are being revised, resulting in creating unique solutions that arise at the interface of physics, nanotechnology, and microbiology. Specifically, physical factors (e.g., pressure, temperature, UV light) are increasingly used for industrial sterilization. Nanoparticles (unmodified or in combination with toxic compounds) are also applied to circumvent in vivo drug resistance mechanisms in bacteria. Recently, bacteriophage-based treatments are also gaining momentum due to their high bactericidal activity and specificity. Although the number of novel approaches for tackling the antimicrobial resistance crisis is snowballing, it is still unclear if any proposed solutions would provide a long-term remedy. This review aims to provide a detailed overview of how bacteria acquire resistance against these non-antibiotic factors. We also discuss innate bacterial defense systems and how bacteriophages have evolved to tackle them.

Quantitative Analysis of Colistin-Resistant Escherichia coli in Retail Meat from Local Vietnamese Markets.

The spread of drug-resistant bacteria via food has contributed to the dissemination of resistant bacteria among humans. However, the status of food contamination with resistant bacteria, particularly the quantitative level of resistant bacteria in food, has not yet been well elucidated. In this study, the abundance of colistin-resistant Escherichia coli in meat samples was quantified to understand the origin of the contamination of meat available in local Vietnamese markets. Fifteen samples each of chicken and pork meat purchased from local Vietnamese markets were assessed for the presence of colistin-resistant E. coli with the mobile colistin resistance gene, mcr. The results showed that 40% (6/15) and 66% (10/15) of the pork and chicken meat samples, respectively, were contaminated with colistin-resistant E. coli. The median quantitative levels of colistin-resistant E. coli in the contaminated pork and chicken samples were 1.8 × 104 and 4.2 × 103 CFU/g, respectively. The results of phylogenetic analysis of isolates from a chicken meat sample showed that the contaminated colistin-resistant E. coli was a mix of multiple phylogenetical clones of bacteria that may have multiplied during sale. This is the first study to quantify the abundance of colistin-resistant E. coli in meat samples.

Rapid profiling of drug-resistant bacteria using DNA-binding dyes and a nanopore-based DNA sequencer

Spread of drug-resistant bacteria is a serious problem worldwide. We thus designed a new sequence-based protocol that can quickly identify bacterial compositions of clinical samples and their drug-resistance profiles simultaneously. Here we utilized propidium monoazide (PMA) that prohibits DNA amplifications from dead bacteria, and subjected the original and antibiotics-treated samples to 16S rRNA metagenome sequencing. We tested our protocol on bacterial mixtures, and observed that sequencing reads derived from drug-resistant bacteria were significantly increased compared with those from drug-sensitive bacteria when samples were treated by antibiotics. Our protocol is scalable and will be useful for quickly profiling drug-resistant bacteria.

Resistance Rates of the most Isolated Bacteria from different Clinical Samples, Kerbala, Iraq

Determining the bacterial causative agents of infections by identifying their antimicrobial patterns will enable health institutions to limit the unnecessary use of antibiotics, and take active ways in preventing the spread of drug-resistant bacteria. This study aimed to identify the most common bacterial isolates responsible for infection and their antibiotic resistance rates. The results showed that Escherichia coli, Staphylococcus aureus (S aureus), and Pseudomonas aeruginosa (P. aeruginosa) represent the most common bacteria isolated with a percentage of 23.9, 18.8, and 16.2%, respectively. High resistance rates were found for the most common bacterial isolates. Other important findings are the presence of extended-spectrum B-lactamase (ESBL) producing bacteria and the appearance of hetero-resistance phenomenon. Moreover, the bacterial infection is mainly occurring in men. No significant correlation was observed in the type of isolated bacteria with patient admission status. E. coli strains were found to be highly resistant to amoxicillin-clavulanic acid, ceftriaxone (88.9%), ceftazidime (85.2%), trimethoprim-sulfamethoxazole (74.1%), and ciprofloxacin (59.3%). Whereas, the highest sensitivity rates were seen with meropenem antibiotic (92.6%). Concerning S. aureus isolates, 100, and approximately 91% of resistant rates were seen to penicillin and cefoxitin, respectively [methicillin-resistant S. aureus (MRSA)]. Approximately 50% of MRSA were vancomycin-resistant S. aureus (VRSA). Resistant rates of P. aeruginosa isolates to gentamycin and ciprofloxacin were 47.1%, amikacin 41.2%, and levofloxacin 35.3%. In conclusion, the current study might reveal that the isolated bacteria could be of critical priority carbapenem-resistant P. aeruginosa, and carbapenem-resistant and 3rd generation cephalosporin-resistant E. coli. In addition, the isolation of high priority bacteria includes vancomycin-resistant methicillin-resistant S. aureus.