Antibiotic Resistance: From the Bench to Patients

It's Not Easy Being Green: A Narrative Review on the Microbiology, Virulence and Therapeutic Prospects of Multidrug-Resistant Pseudomonas aeruginosa

Pseudomonas aeruginosa is the most frequent cause of infection among non-fermenting Gram-negative bacteria, predominantly affecting immunocompromised patients, but its pathogenic role should not be disregarded in immunocompetent patients. These pathogens present a concerning therapeutic challenge to clinicians, both in community and in hospital settings, due to their increasing prevalence of resistance, and this may lead to prolonged therapy, sequelae, and excess mortality in the affected patient population. The resistance mechanisms of P. aeruginosa may be classified into intrinsic and acquired resistance mechanisms. These mechanisms lead to occurrence of resistant strains against important antibiotics-relevant in the treatment of P. aeruginosa infections-such as β-lactams, quinolones, aminoglycosides, and colistin. The occurrence of a specific resistotype of P. aeruginosa, namely the emergence of carbapenem-resistant but cephalosporin-susceptible (Car-R/Ceph-S) strains, has received substantial attention from clinical microbiologists and infection control specialists; nevertheless, the available literature on this topic is still scarce. The aim of this present review paper is to provide a concise summary on the adaptability, virulence, and antibiotic resistance of P. aeruginosa to a readership of basic scientists and clinicians.

Multidrug-Resistant and Extensively Drug-Resistant Enterobacteriaceae: Prevalence, Treatments, and Outcomes - A Retrospective Cohort Study

Background

Drug-resistant gram-negative bacteria (GNB) are a global public health threat, especially in intensive care units (ICU). This study explored the prevalence of drug-resistant Enterobacteriaceae infections in an ICU in Saudi Arabia. The appropriateness of the antibiotic therapies used and their ability to improve the clinical outcomes were also assessed.

Methods

A retrospective study was conducted from 2015 to 2018 in the different ICUs of a tertiary-care hospital in Saudi Arabia. Positive cultures for multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR) Enterobacteriaceae, including Klebsiella pneumoniae, Escherichia coli, and Enterobacter sp., were included. The primary outcomes involved microbiological cure and 30 days in-hospital mortality rate, while the secondary outcome included the length of hospital stay (LOS). Regression models were used to assess the relationship between appropriateness of the antibiotic therapy and clinical outcomes.

Results

Of the 227 Enterobacteriaceae cultures included in this study, 60% were either MDR (n= 130) or XDR (n= 8) infections; no PDR Enterobacteriaceae cultures were identified. Majority of the patients were female (54%), and the average age was 60.1 ± 17.7 years. MDR/XDR cultures primarily comprised E. coli (51.4%), followed by K. pneumoniae (33%) and Enterobacter sp. (16%). Most commonly used antibiotics were piperacillin/tazobactam (53%), carbapenems (47%), and cephalosporins (21.3%). Antibiotic therapy was considered appropriate in only 85 of 138 (61.59%) patients. Microbiological cure rate was achieved in 40% of the cases, and in-hospital death rate was 84%. The average LOS was 27 days. Appropriateness of the antibiotic therapy prescribed could not predict any of the study outcomes.

Conclusion

The study revealed a high prevalence of drug-resistant Enterobacteriaceae infections, which were associated with a high mortality rate. Therefore, it is essential to assess the effectiveness of antimicrobial stewardship program and infection prevention and control practices, particularly in critically ill patients.

Antimicrobial susceptibility patterns of bacteria that commonly cause bacteremia at a tertiary hospital in Zambia

Background: Bloodstream infections and antimicrobial resistance cause global increases in morbidity and mortality. Aim: We evaluated the antimicrobial susceptibility patterns of bacteria that commonly cause bacteremia in humans. Materials & methods: We conducted a retrospective cross-sectional study at the University Teaching Hospitals in Lusaka, Zambia, using Laboratory Information Systems. Results: The commonest isolated bacteria associated with sepsis were Klebsiella pneumoniae. The distribution of bacteria associated with bacteremia in different wards and departments pneumonia. The distribution of bacteria associated with bacteremia in different wards and departments at University Teaching Hospitals was were statistically significant (χ2 = 1211.518; p < 0.001). Conclusion: K. pneumoniae, Escherichia coli, Pantoea agglomerans and Enterococcus species have developed high resistance levels against ampicillin, cefotaxime, ciprofloxacin, gentamicin and trimethoprim/sulfamethoxazole and a very low resistance levels against imipenem and Amikacin.

Association between Physicians' Perception of Shared Decision Making with Antibiotic Prescribing Behavior in Primary Care in Hubei, China: A Cross-Sectional Study

Shared decision-making (SDM) has been advocated as one effective strategy for improving physician–patient relationships and optimizing clinical outcomes. Our study aimed to measure physicians’ perception of SDM and establish the relationship between physicians’ perception of SDM and prescribing behavior in patients with upper respiratory tract infections. One cross-sectional study was conducted in Hubei Province from December 2019 to January 2020. The SDM questionnaire and prescription data of 2018 from electronic health records data were matched for each physician in this study. Multilevel modeling was applied to explore the relationship between physicians’ perception of SDM and antibiotic prescribing in primary care. Analyses were statistically controlled for demographic characteristics of the physicians and patients. Physicians’ positive perception of SDM had small but statistically significant effects on lower prescribing of antibiotics in the patient group aged over 40 years (odds ratio (OR) < 1; p < 0.05). Moreover, female physicians (OR = 0.71; p = 0.007) with higher educational levels (bachelor’s degree and above; OR = 0.71; p = 0.024) were significantly associated with the prescribing of less antibiotics (p < 0.05). A more positive perception of SDM was demonstrated as one significant predictor of less prescribing of antibiotics in the patient group over 40 years. There may be a promising focus of implementing SDM strategies targeting physician–patient communication in primary care.

Detection of VIM, NDM and OXA-48 producing carbapenem resistant Enterobacterales among clinical isolates in Southern Hungary

Infections caused by carbapenem-resistant Enterobacterales (CRE) present an important therapeutic problem, as there are limited number of effective therapeutic alternatives available. In this study, phenotypic and genotypic methods were used to characterize carbapenemase-production and other resistance-determinants (AmpC and ESBL-production, efflux pump-overexpression) in 50 isolates (Klebsiella spp. n = 35, Escherichia coli n = 12 and Enterobacter cloacae complex n = 3) collected at the Albert Szent-Györgyi Clinical Center (University of Szeged) between 2014 and 2017. Minimum inhibitory concentrations of meropenem, sulfamethoxazole/trimethoprim, tigecycline, amikacin, moxifloxacin, colistin and fosfomycin were also determined. 24% of isolates were AmpC-producers, while 30% carried blaCTX-M ESBL-genes. Carbapenemase-genes were detected in 18 (36%) of the tested isolates: in 2 isolates blaNDM, in 6 isolates blaOXA-48-like and in 12 isolates, blaVIM was detected by PCR. The species-distribution for isolates positive for carbapenemase-genes was the following: Klebsiella pneumoniae n = 11, Klebsiella oxytoca n = 1, E. coli n = 5, E. cloacae complex n = 1. Efflux pump-overexpression based on the PAβN-screening agar was shown in n = 3 of the tested strains. In nine isolates (18%), carbapenemase and ESBL-genes were detected simultaneously. Highest levels of resistance were noted for fosfomycin (74%) and moxifloxacin (70%), while all isolates were susceptible to colistin. Among applied phenotypic tests in this study the modified carbapenem inactivation method (mCIM) proved to be the most accurate one compared to that of PCR results.

Bacterial Contaminants and Antibiogram of Ghana Paper Currency Notes in Circulation and Their Associated Health Risks in Asante-Mampong, Ghana

Transmission of pathogens through currency notes has become very relevant in today's world due to COVID-19 pandemic. This study profiled microbial flora and their antibiotic activities from Ghana paper currency (GH¢) notes in circulation in Mampong Municipal of Ashanti Region, Ghana. The study employed a cross-sectional design to assess bacterial contaminants and their antibiotic activities from January to May 2019. A total of 70 GH¢ notes consisting of 15 each of GH¢1, GH¢2, and GH¢5; 10 each of GH¢10 and GH¢20; and 5 of GH¢50 were randomly sampled from persons at different shops, canteens, and commercial drivers. The surfaces of each GH¢ note were gently swabbed, and tenfold serial dilutions made were inoculated on plate count agar (PCA), MacConkey agar, mannitol salt agar, and deoxycholate citrate agar. The study used appropriate laboratory and biochemical tests for bacterial identification. SPSS-IBM version 16.0 was used to analyze the data. Of the 70 GH¢ notes studied, 97.1% were contaminated with one or more bacterial isolates. Mean counts on PCA ranged between 3.2 cfu/ml × 10⁵ and 4.7 cfu/ml × 10⁵ on GH¢ notes. Of 124 bacteria isolated, 34 (27.4%), 30 (24.2%), 22 (17.7%), 17 (13.7%), 13 (10.5%), and 8 (6.5%) were from GH¢1, GH¢2, GH¢10, GH¢5, GH¢20, and GH¢50, respectively (p < 0.05). Bacterial isolates were Escherichia coli (28.23%), Staphylococcus aureus (16.94%), coagulase-negative Staphylococcus (16.13%), Klebsiella species (11.29%), Salmonella species (9.68%), Shigella species (8.87%), Pseudomonas aeruginosa (5.65%), and Proteus species (3.23%). GH¢ notes had 25.81%, 20.16%, 19.35%, 17.74%, and 16.94% from meat shops, commercial drivers, canteens, grocery shops, and vegetable shops, respectively. All bacteria were 100% resistant to erythromycin, 87.5% to tetracycline, chloramphenicol, and cotrimoxazole, 75% to vancomycin, while 87.50% sensitive to amikacin. The GH¢ notes were heavily colonized with potential pathogens, which are resistant to most commonly used antibiotics and could pose a health threat to users during commercial transactions.

Knowledge, attitude, and practices of community pharmacy staff toward antimicrobial stewardship programs: a cross-sectional study from Northeastern China

BACKGROUND

Antimicrobial resistance is one of the most significant challenges of the twenty-first century, and the illegal sale of antimicrobial drugs at community pharmacies is a driver of antimicrobial resistance. This study explores the knowledge, attitudes, and practices (KAP) of pharmacy staff toward antimicrobial stewardship programs (ASPs).

METHODS

We conducted a descriptive cross-sectional study among community pharmacy staff in Northeastern China, from April 1 to 31 May 2019, using a self-administered KAP questionnaire comprising 20 items. The data analysis was carried out by employing Mann-Whitney and Kruskal-Wallis tests.

RESULTS

A response rate of 98.5% (394/400) was obtained. The majority of participants (94.9%) demonstrated a good understanding of antimicrobial use, but they lacked an adequate understanding of ASPs. Nearly half of the participants (40.6%) reported that they sold antimicrobials to patients without a prescription. Education level, age, occupation, and experience were all significantly associated (P < 0.05) with participants' median ASPs scores. Besides, the presence of a licensed pharmacist (OR 46.327, 95% CI 2.443-878.451, P = 0.011) was the main factor associated with the pharmacy staff's understanding of antimicrobial use policies.

CONCLUSIONS

The participants' knowledge of antimicrobials was good, and their attitudes regarding ASPs were positive, but their practices regarding ASPs were poor.

Economic Burden of Patients with Bloodstream Infections Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli

Background

The prevalence of infections with extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) is increasing worldwide, but the economic impact of ESBL-EC bloodstream infection (BSI) has not been comprehensively evaluated.

Patients and Methods

A retrospective cohort including patients hospitalized at a tertiary hospital between January 2013 and December 2016 who were confirmed with a BSI of ESBL-EC or non-ESBL-EC was set. Clinical data and medical costs were collected by chart review of electronic and paper medical records. The economic burden was evaluated with disability-adjusted life years (DALYs).

Results

A total of 580 patients with E. coli BSI, comprising 333 patients (57.4%) with ESBL-EC BSI and 247 patients (42.6%) with non-ESBL-EC BSI, were identified. There were no significant differences in comorbidity and severity of patients between ESBL-EC and non-ESBL-EC BSI. The median length of stay (LOS) after bacteremia was 12 days for ESBL-EC (interquartile range, 7 to 21) versus 11 days for non-ESBL-EC (interquartile range, 7 to 21) (P = 0.38), and appropriate empirical antimicrobial therapy occurred in 87.4% versus 89.9% (P = 0.353). The mortalities were 20.1% versus 17.4% (P = 0.41). Patients with ESBL-EC did not have significantly different in-hospital medical costs to those with non-ESBL-EC (median, $8048.68 vs $7476.84, respectively, with a difference of $571.84, P = 0.321). In the non-ESBL-EC group, 247 patients lost 531.05 DALYs in total, with an average of 2.15 DALYs per person, while in the ESBL-EC group, 333 patients lost 692.64 DALYs in total, with an average of 2.08 DALYs per person. There is no significant difference in average DALYs (P = 0.343).

Conclusion

In conclusion, patients with BSI due to ESBL-EC did not cost more than patients with BSI due to non-ESBL-EC. This phenomenon may be attributed to timely and effective antibiotic treatment, but the initial empiric therapy with second- or third-line antibiotics in non-ESBL-EC BSI should be corrected.

The Principles, Mechanisms, and Benefits of Unconventional Agents in the Treatment of Biofilm Infection

Today, researchers are looking at new ways to treat severe infections caused by resistance to standard antibiotic therapy. This is quite challenging due to the complex and interdependent relationships involved: the cause of infection-the patient-antimicrobial agents. The sessile biofilm form is essential in research to reduce resistance to very severe infections (such as ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, and Enterobacter spp). The purpose of this study is to elucidate the mechanisms of the occurrence, maintenance, and suppression of biofilm infections. One form of biofilm suppression is the efficient action of natural antagonists of bacteria-bacteriophages. Bacteriophages effectively penetrate the biofilm's causative cells. They infect those bacterial cells and either destroy them or prevent the infection spreading. In this process, bacteriophages are specific, relatively easy to apply, and harmless to the patient. Antimicrobial peptides (AMPs) support the mechanisms of bacteriophages' action. AMPs could also attack and destroy infectious agents on their own (even on biofilm). AMPs are simple, universal peptide molecules, mainly cationic peptides. Additional AMP research could help develop even more effective treatments of biofilm (bacteriophages, antibiotics, AMPs, nanoparticles). Here, we review recent unconventional agents, such as bacteriophages and AMPs, used for eradication of biofilm, providing an overview of potentially new biofilm treatment strategies.

Emerging and Re-Emerging Leishmaniases in the Mediterranean Area: What Can Be Learned from a Retrospective Review Analysis of the Situation in Morocco during 1990 to 2010?

In Morocco, cutaneous and visceral leishmaniases represent a public health concern. In this opinion paper, we propose to highlight chosen elements that have governed the drastic increase in the incidence of leishmaniases recorded in Morocco during the period between 1990 to 2010 in order to guide the prediction of the expansion of diseases and epidemic events. We highlight that the dispersion of the zoonotic cutaneous leishmaniasis (ZCL) form, caused by the Leishmania major parasite, appears to be closely related to that of its arthropod vector density, which is sensitive to changes in climate. The dissemination of anthroponotic cutaneous leishmaniasis (ACL) was related to an increase in human travel and local tourism during the studied decades. These are linked to economic expansion and infrastructure development. Interestingly, the main ACL foci are spatially aligned with the highways, and their occurrence was synchronized with the building of transportation infrastructure. During the above-mentioned decades, the zoonotic visceral leishmaniasis (ZVL) caused by Leishmania infantum has expanded from its historical northern territories, dispersing outwards in all directions. This spread follows the emergence of hamlets and villages connecting with major cities.

Methicillin-Resistant Staphylococcus aureus (MRSA): One Health Perspective Approach to the Bacterium Epidemiology, Virulence Factors, Antibiotic-Resistance, and Zoonotic Impact

Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen and a historically emergent zoonotic pathogen with public health and veterinary importance. In humans, MRSA commonly causes severe infectious diseases, including food poisoning, pyogenic endocarditis, suppurative pneumonia, otitis media, osteomyelitis, and pyogenic infections of the skin, soft tissues. In the horse, MRSA could cause a localized purulent infection and botryomycosis; in cattle and ewe, localized pyogenic infection and severe acute mastitis with marked toxemia; in sheep, abscess disease resembles caseous lymphadenitis caused by anaerobic strains; in dogs and cats, pustular dermatitis and food poisoning; in pig, exudative epidermatitis “greasy pig disease; in birds, MRSA causes bumble-foot. The methicillin resistance could be determined by PCR-based detection of the mecA gene as well as resistance to cefoxitin. In Egypt, MRSA is one of the important occasions of subclinical and clinical bovine mastitis, and the prevalence of MRSA varies by geographical region. In this review, we are trying to illustrate variable data about the host susceptibility, diseases, epidemiology, virulence factors, antibiotic resistance, treatment, and control of MRSA infection.

Clinical Characteristics and Risk Factors for Bloodstream Infection Due to Carbapenem-Resistant Klebsiella pneumoniae in Patients with Hematologic Malignancies

Purpose

The aim was to examine the clinical characteristics and risk factors for bloodstream infection (BSI) due to carbapenem-resistant Klebsiella pneumoniae (CRKP) in patients with hematologic malignancies.

Materials and Methods

A single-centre, retrospective case–control study representing 734 patients with hematologic malignancies between January 1, 2017, and December 31, 2018, was conducted. Demographic and clinical data were collected from the hospital electronic medical records system.

Results

Among the 734 patients with hematologic malignancies, 3% (22/734) of the patients developed CRKP BSI during their hospitalization. Overall 28-day all-cause mortality reached 77.3% (17/22). Patients with Pitt bacteremia score (PBS) >4, pneumonia and septic shock were more frequent in the non-survivors versus the survivors. Compared with the non-survivors in antimicrobial treatment, combination therapy of tigecycline and polymyxin B was more common in the survivors. The independent risk factors associated with CRKP BSI were CRKP rectal colonization (OR, 11.067; CI=4.43–27.644; P<0.001; 3 points), severe neutropenia (OR, 4.095; CI=0.876–19.141; P=0.073; 1 point) and invasive mechanical ventilation (IMV) within the previous 30 days to onset of BSI (OR, 18.444; CI=1.787–190.343; P=0.014; 4 points). The total risk score of ≥5 indicated that the probability of CRKP BSI occurrence was above 48%.

Conclusion

CRKP BSI in patients with hematologic malignancies is associated with high mortality. The risk factor-based prediction model might help clinicians to start prompt effective anti-infective therapy in patients with suspicion of CRKP BSI and improve outcomes.

Evidence of the Practice of Self-Medication with Antibiotics among the Lay Public in Low- and Middle-Income Countries: A Scoping Review

The current scoping review is an attempt to explore the key reasons, determinants, patterns and prevalence related to self-medication with antibiotics (SMA) among the lay public. An online search was conducted using Google Scholar, Science Direct, ProQuest and PubMed. A two-phase mapping approach was used. In the first phase, studies were screened. In the second phase, the data were extracted from selected studies followed by the assessment of data quality. A total of 24 studies were included; 20 were cross-sectional, 3 were qualitative and one was observational. The most common indications were flu, cough, common colds, sore throat, diarrhea, toothache and fever. The most common determinants reported were past good experience and suggestions from friends or relatives. The use of SMA was observed to be more frequent in younger aged individuals belonging to low- or middle-income groups. The prevalence rate was reported to be high among the South Asian lay public and may be a major contributor to antibiotic resistance. In conclusion, this scoping review identifies a need for education campaigns and mass media campaigns to strengthen lay public awareness about the side effects and risks associated with SMA. In addition to this, there is a need to implement strict policies by government agencies to restrict over the counter availability of antibiotics.

Clinician and Patient Factors Influencing Treatment Decisions: Ethnographic Study of Antibiotic Prescribing and Operative Procedures in Out-of-Hours and General Dental Practices

Operative treatment is indicated for most toothache/dental abscesses, yet antibiotics instead of procedures are often prescribed. This ethnographic study aimed to identify clinician and patient factors influencing urgent dental care for adults during actual appointments; and to identify elements sensitive to context. Appointments were observed in out-of-hours and general dental practices. Follow-up interviews took place with dentists, dental nurses, and patients. Dentist and patient factors were identified through thematic analysis of observation records and appointment/interview transcripts. Dentist factors were based on a published list of factors influencing antibiotic prescribing for adults with acute conditions across primary health care and presented within the Capability-Opportunity-Motivation-Behaviour model. Contextually sensitive elements were revealed by comparing the factors between settings. In total, thirty-one dentist factors and nineteen patient factors were identified. Beliefs about antibiotics, goals for the appointment and access to dental services were important for both dentists and patients. Dentist factors included beliefs about the lifetime impact of urgent dental procedures on patients. Patient factors included their communication and negotiation skills. Contextual elements included dentists’ concerns about inflicting pain on regular patients in general dental practice; and patients’ difficulties accessing care to complete temporary treatment provided out of hours. This improved understanding of factors influencing shared decisions about treatments presents significant opportunity for new, evidence-based, contextually sensitive antibiotic stewardship interventions.

Synthesis, Characterization, and Antibacterial Evaluation of Heteroleptic Oxytetracycline-Salicylaldehyde Complexes

A new series of mixed ligand complexes of Cd(II) and Mo(V) were successfully synthesized by refluxing the mixture solution of oxytetracycline hydrochloride (OTC.HCl) with an aqueous and alcoholic solution of metal (M = Cd(II) and Mo(V)) salts and an alcoholic solution of salicylaldehyde (Sal). The complexes were characterized by modern analytical and spectral methods such as elemental microanalysis, pH, conductivity, surface tension, viscosity, melting point, and spectral methods such as FT-IR, NMR, electronic absorption, SEM, and mass spectrometry. Conductivity measurements of the complexes revealed their electrolytic nature. The kinetic and thermal stabilities were investigated using thermogravimetric and differential thermal analysis techniques. Thermodynamic and kinetic parameters such as E∗, ΔH∗, ΔS∗, and ΔG∗ were calculated from TG curves using the Coats–Redfern method. Geometry optimization of the proposed structure of the complexes was achieved by running MM2 calculations in a Gaussian-supported CS ChemOffice 3D Pro.12.0 version software. The final optimized geometrical energies for respective Cd-OTC/Sal and Mo-OTC/Sal complexes were found to be 923.1740 and 899.3184 kcal/mol. The electronic absorption spectral study revealed a tetrahedral geometry for the Cd-OTC/Sal complex and octahedral geometry for the Mo-OTC/Sal complex. The antibacterial sensitivity of the complexes was evaluated against three bacterial pathogens such as S. aureus, E. coli, and P. mirabilis using the modified Kirby–Bauer paper disc diffusion method. The antibacterial study revealed significant growth inhibitory action of the complexes.

Utility of Photodynamic Therapy in Dentistry: Current Concepts

The significant growth in scientific and technological advancements within the field of dentistry has resulted in a wide range of novel treatment modalities for dentists to use. Photodynamic therapy (PDT) is an emerging, non-invasive treatment method, involving photosensitizers, light of a specific wavelength and the generation of singlet oxygen and reactive oxygen species (ROS) to eliminate unwanted eukaryotic cells (e.g., malignancies in the oral cavity) or pathogenic microorganisms. The aim of this review article is to summarize the history, general concepts, advantages and disadvantages of PDT and to provide examples for current indications of PDT in various subspecialties of dentistry (oral and maxillofacial surgery, oral medicine, endodontics, preventive dentistry, periodontology and implantology), in addition to presenting some images from our own experiences about the clinical success with PDT.

Molecular Mechanisms and Epidemiology of Carbapenem-Resistant Escherichia coli Isolated from Chinese Patients During 2002-2017

Background

The emergence and spread of carbapenem-resistant Escherichia coli (E. coli) pose a serious threat to human health worldwide. This study aimed to investigate the molecular mechanisms underlying carbapenem resistance and their prevalence among E. coli in China.

Methods

A collection of 5796 E. coli clinical isolates were collected from the First Affiliated Hospital of Wenzhou Medical University from 2002 to 2017. Sensitivity to antibiotics was determined using the agar dilution method. The detection of carbapenemases production and the prevalence of resistance-associated genes were investigated through modified carbapenem inactivation method (mCIM), PCR and sequencing. The mutations in outer membrane porins genes (ompC and ompF) were also analyzed by PCR and sequencing assays. The effect of efflux pump mechanism on carbapenem resistance was also tested. E. coli were typed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST).

Results

A total of 58 strains (1.0%) of carbapenem-resistant E. coli were identified. The strains carrying bla_KPC-2 and bla_NDM accounted for 22.4% (13/58) and 51.7% (30/58), respectively. Among bla_NDM- positive strains, 27 bla_NDM genes were assigned to bla_NDM-5, while the remaining three strains were bla_NDM-1, whereas bla_VIM, bla_IMP, bla_OXA-48, and bla_SHV were not found. The CTX-M-type β-lactamase genes accounted for 96.6% (56/58). In addition, bla_TEM-1 genes were identified in 58.6% of tested strains. In carbapenem-resistant isolates, mutations in OmpC (the majority of mutated sites were D192G and Q104_F141del, accounting for 54.5%) and OmpF (large deletions S75_V127del, W83_D135del and Q88_D135del) were detected. Of note, the antibiotic resistance was not associated with overexpression of efflux pump. Moreover, MLST categorized the 58 carbapenem-resistant isolates into 19 different sequence types. PFGE analysis revealed that homology among the carbapenem-resistant isolates was low and sporadic.

Conclusion

The bla_NDM was the principal resistance mechanism of carbapenem-resistant E. coli in the hospital. bla_NDM-5 is becoming a new threat to public health and the alteration of outer membrane porins might help further increase the MIC of carbapenem.

Nine-Year Analysis of Isolated Pathogens and Antibiotic Susceptibilities of Infectious Endophthalmitis from a Large Referral Eye Center in Southern China

Purpose

To analyze the pathogen spectrum of isolated pathogens and antibiotic susceptibility trends of infectious endophthalmitis over 9 years from a large referral eye center in southern China.

Methods

Data from all inpatients who were clinically diagnosed with infectious endophthalmitis and underwent microbiological evaluation at the Zhongshan Ophthalmic Center from January 2010 to December 2018 were collected retrospectively and analyzed according to different clinical etiologies.

Results

A total of 816 cases were collected in the study. Open-globe injuries had caused 473 (57.97%) cases, 70 (8.58%) cases presented endophthalmitis after infectious keratitis, 156 (19.12%) cases were postoperative, and endogenous causes accounted for 117 (14.34%) cases. Among the 309 culture-positive cases, the predominant pathogen for both postoperative and posttraumatic endophthalmitis was gram-positive cocci (59.52% and 49.72%, respectively). Regarding keratitis-related endophthalmitis, the main pathogens were filamentous fungi (57.58%) and gram-negative bacilli (30.30%). The pathogens of endogenous endophthalmitis were almost evenly distributed among gram-positive cocci, gram-negative bacilli, and fungi. Eighty-five (10.42%) cases underwent evisceration/enucleation, including 42 cases secondary to keratitis-related endophthalmitis. The incidence of evisceration/enucleation was much higher in keratitis-related endophthalmitis than the total endophthalmitis population (χ² =123.61, P<0.001). Overall bacteria showed high susceptibility to fluoroquinolones (75.36–100.00%). Gram-positive cocci showed much higher sensitivity to cephalosporins compared to gram-negative bacilli (85.11–92.59% vs 25.42–35.72%). For the five first-line antibiotics analyzed for time trend of susceptibility, four exhibited a significant decrease of susceptibility from 2010–2014 to 2015–2018.

Conclusion

Between 2010 and 2018, posttraumatic endophthalmitis was the most common form of the treated endophthalmitis in Zhongshan Ophthalmic Center. The causative pathogens varied according to different clinical settings. Even though the overall antibiotic susceptibilities were fairly high, we observed a substantial decrease of susceptibility for most first-line antibiotics.

Characterization of Resistance in Gram-Negative Urinary Isolates Using Existing and Novel Indicators of Clinical Relevance: A 10-Year Data Analysis

Classical resistance classifications (multidrug resistance [MDR], extensive drug resistance [XDR], pan-drug resistance [PDR]) are very useful for epidemiological purposes, however, they may not correlate well with clinical outcomes, therefore, several novel classification criteria (e.g., usual drug resistance [UDR], difficult-to-treat resistance [DTR]) were introduced for Gram-negative bacteria in recent years. Microbiological and resistance data was collected for urinary tract infections (UTIs) retrospectively, corresponding to the 2008.01.01–2017.12.31. period. Isolates were classified into various resistance categories (wild type/susceptible, UDR, MDR, XDR, DTR and PDR), in addition, two new indicators (modified DTR; mDTR and mcDTR) and a predictive composite score (pMAR) were introduced. Results: n = 16,240 (76.8%) outpatient and n = 13,386 (69.3%) inpatient UTI isolates were relevant to our analysis. Citrobacter-Enterobacter-Serratia had the highest level of UDR isolates (88.9%), the Proteus-Providencia-Morganella group had the highest mDTR levels. MDR levels were highest in Acinetobacter spp. (9.7%) and Proteus-Providencia-Morganella (9.1%). XDR- and DTR-levels were higher in non-fermenters (XDR: 1.7%–4.7%. DTR: 7.3%–7.9%) than in Enterobacterales isolates (XDR: 0%–0.1%. DTR: 0.02%–1.5%). Conclusions: The introduction of DTR (and its’ modifications detailed in this study) to the bedside and in clinical practice will definitely lead to substantial benefits in the assessment of the significance of bacterial resistance in human therapeutics.

Knowledge, Attitude and Practice of Community Pharmacists Regarding Antibiotic Use and Infectious Diseases: A Cross-Sectional Survey in Hungary (KAPPhA-HU)

One of the key drivers for the emergence and spread of antimicrobial resistance (AMR) is non-prudent antibiotic (AB) use, which results in selection pressure towards relevant bacteria. Community pharmacists have pivotal roles in facilitating the prudent use of ABs that have been demonstrated by several studies worldwide. The aim of our present study was to evaluate the knowledge, attitude and practice of community pharmacists related to AB use and infectious diseases in Hungary. A descriptive cross-sectional survey was performed among community pharmacists in Hungary with the use of an anonymous, structured and pilot-tested questionnaire. Data collection ran between January 2016 and January 2018; n = 339 community pharmacists nationwide were approached with our questionnaire, out of which 192 filled out our survey. Hungarian pharmacists have appropriate knowledge regarding ABs and antimicrobial therapy, and they realize the public health impact of the growing AMR. Twenty-five percent of participants admitted to giving out non-prescription ABs at least once in the last year. The age and presence of board-certified specializations were shown to be significant factors of self-perceived knowledge and professional attitudes. Educational strategies and interventions specifically aimed at focusing on identified shortcomings and changing certain attitudes could substantially improve AB dispensing and AB use, in addition to minimizing resistance.

The Role of Gram-Negative Bacteria in Urinary Tract Infections: Current Concepts and Therapeutic Options

Urinary tract infections (UTIs) are some of the most common infections in human medicine worldwide, recognized as an important public health concern to healthcare systems around the globe. In addition, urine specimens are one of the most frequently submitted samples for culture to the clinical microbiology laboratory, exceeding the number of most of the other sample types. The epidemiology, species-distribution and susceptibility-patterns of uropathogens vary greatly in a geographical and time-dependent manner and it also strongly correlated with the reported patient population studied. Nevertheless, many studies highlight the fact that the etiological agents in UTIs have changed considerably, both in nosocomial and community settings, with a shift towards "less common" microorganisms having more pronounced roles. There is increasing demand for further research to advance diagnostics and treatment options, and to improve care of the patients. The aim of this review paper was to summarize current developments in the global burden of UTI, the diagnostic aspects of these infectious pathologies, the possible etiological agents and their virulence determinants (with a special focus on the members of the Enterobacterales order), current guidelines and quality indicators in the therapy of UTIs and the emergence of multidrug resistance in urinary pathogens.

Levonadifloxacin, a Novel Broad-Spectrum Anti-MRSA Benzoquinolizine Quinolone Agent: Review of Current Evidence

Levonadifloxacin and its prodrug alalevonadifloxacin are novel broad-spectrum anti-MRSA agents belonging to the benzoquinolizine subclass of quinolone, formulated for intravenous and oral administration, respectively. Various in vitro and in vivo studies have established their antimicrobial spectrum against clinically significant Gram-positive, Gram-negative, atypical, and anaerobic pathogens. The potent activity of levonadifloxacin against MRSA, quinolone-resistant Staphylococcus aureus, and hetero-vancomycin-intermediate strains is an outcome of its well-differentiated mechanism of action involving preferential targeting to DNA gyrase. Potent anti-staphylococcal activity of levonadifloxacin was also observed in clinically relevant experimental conditions such as acidic pH, the intracellular environment, and biofilms, suggesting that the drug is bestowed with enabling features for the treatment of difficult-to-treat MRSA infections. Levonadifloxacin also retains clinically relevant activity against resistant respiratory pathogens such as macrolide- and penicillin-resistant Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, and Moraxella catarrhalis and, in conjunction with clinically established best-in-class human epithelial lung fluid concentration, has promising potential in the management of recalcitrant respiratory infections. Attractive features, such as resistance to NorA efflux, divergent mechanism of action in S. aureus, cidality against high-inoculum cultures, and low mutant prevention concentration, are likely to confer favorable resistance-suppression features to both agents. In vivo studies have shown promising efficacy in models of acute bacterial skin and skin structure infection, respiratory infections, pyelonephritis, and peritonitis at human-equivalent mouse doses. Both formulations were well tolerated in multiple phase I studies and overall showed a dose-dependent exposure. In particular, oral alalevonadifloxacin showed excellent bioavailability (~90%), almost mirroring the pharmacokinetic profile of intravenous levonadifloxacin, indicating the prodrug's seamless absorption and efficient cleavage to release the active parent drug. Hepatic impairment studies showed that clinical doses of levonadifloxacin/alalevonadifloxacin are not required to be adjusted for various degrees of hepatic impairment. With the successful completion of phase II and phase III studies for both levonadifloxacin and alalevonadifloxacin, they represent clinically attractive therapeutic options for the treatment of infections caused by multi-drug-resistant Gram-positive organisms. Herein, we review the current evidence on therapeutically appealing attributes of levonadifloxacin and alalevonadifloxacin, which are based on a range of non-clinical in vitro and in vivo investigations and clinical studies.

The Role of Drug Repurposing in the Development of Novel Antimicrobial Drugs: Non-Antibiotic Pharmacological Agents as Quorum Sensing-Inhibitors

Background: The emergence of multidrug-resistant organisms (MDROs) is a global public health issue, severely hindering clinicians in administering appropriate antimicrobial therapy. Drug repurposing is a drug development strategy, during which new pharmacological applications are identified for already approved drugs. From the viewpoint of the development of virulence inhibitors, inhibition of quorum sensing (QS) is a promising route because various important features in bacterial physiology and virulence are mediated by QS-dependent gene expression. Methods: Forty-five pharmacological agents, encompassing a wide variety of different chemical structures and mechanisms of action, were tested during our experiments. The antibacterial activity of the compounds was tested using the broth microdilution method. Screening and semi-quantitative assessment of QS-inhibition by the compounds was performed using QS-signal molecule-producing and indicator strains. Results: Fourteen pharmaceutical agents showed antibacterial activity in the tested concentration range, while eight drugs (namely 5-fluorouracil, metamizole-sodium, cisplatin, methotrexate, bleomycin, promethazine, chlorpromazine, and thioridazine) showed dose-dependent QS-inhibitory activity in the in vitro model systems applied during the experiments. Conclusions: Virulence inhibitors represent an attractive alternative strategy to combat bacterial pathogens more efficiently. Some of the tested compounds could be considered potential QS-inhibitory agents, warranting further experiments involving additional model systems to establish the extent of their efficacy.

In Vitro Benznidazole and Nifurtimox Susceptibility Profile of Trypanosoma cruzi Strains Belonging to Discrete Typing Units TcI, TcII, and TcV

We ascertain the in vitro Benznidazole (BZN) and Nifurtimox (NFX) susceptibility pattern of epimastigotes, trypomastigotes, and amastigotes of 21 T. cruzi strains, from patients, reservoir, and triatomine bugs of various geographic origins. Using this panel of isolates, we compute the Epidemiological cut off value (CO_wt). Then, the frequency of the susceptible phenotype (Wild type) towards benznidazole (BZN) and nifurtimox (NFX) within this set of strains belonging to three discrete typing units (DTUs), TcI, TcII, and TcV, was deduced. We observed that the susceptibility status of individual T. cruzi isolates toward BZN and NFX is related to the genetic background and underlying factors that are probably related to the individual life trait history of each strain. Analyzing drug susceptibility in this conceptual framework would offer the possibility to evidence a link between isolates expressing a low susceptibility level (not wild-type) as defined by the CO_wt value and none-curative treatment. It will also permit us to track drug-resistant parasites in the T. cruzi population.