Opportunities to Enhance Diagnostic Testing and Antimicrobial Stewardship: A Qualitative Multinational Survey of Healthcare Professionals.

INTRODUCTION: Antimicrobial resistance (AMR) is a global public health challenge. Global efforts to decrease AMR through antimicrobial stewardship (AMS) initiatives include education and optimising the use of diagnostic technologies and antibiotics. Despite this, economic and societal challenges hinder AMS efforts. The objective of this study was to obtain insights from healthcare professionals (HCPs) on current challenges and identify opportunities for optimising diagnostic test utilisation and AMS efforts. METHODS: Three hundred HCPs from six countries (representing varied gross national incomes per capita, healthcare system structure, and AMR rates) were surveyed between November 2022 through January 2023. A targeted literature review and expert interviews were conducted to inform survey development. Descriptive statistics were used to summarise survey responses. RESULTS: These findings suggest that the greatest challenges to diagnostic test utilisation were economic in nature; many HCPs reported that AMS initiatives were lacking investment (32.3%) and resourcing (40.3%). High resistance rates were considered the greatest barriers to appropriate antimicrobial use (52.0%). Most HCPs found local and national guidelines to be very useful (≥ 51.0%), but areas for improvement were noted. The importance of AMS initiatives was confirmed; diagnostic practices were acknowledged to have a positive impact on decreasing AMR (70.3%) and improving patient outcomes (81.0%). CONCLUSION: AMS initiatives, including diagnostic technology utilisation, are pivotal to decreasing AMR rates. Interpretation of these survey results suggests that while HCPs consider diagnostic practices to be important in AMS efforts, several barriers to successful implementation still exist including patient/institutional costs, turnaround time of test results, resourcing, AMR burden, and education. While some barriers differ by country, these survey results highlight areas of opportunities in all countries for improved use of diagnostic technologies and broader AMS efforts, as perceived by HCPs. Greater investment, resourcing, education, and updated guidelines offer opportunities to further strengthen global AMS efforts.

Antimicrobials are medications used to treat infections caused by bacteria (e.g. antibiotics), viruses, parasites, and fungi. Over time, these microbes may become resistant to antimicrobials, limiting how well they work. This often happens as a result of overuse, using antimicrobials when there is not an infection, or using an inappropriate antimicrobial. Antimicrobial resistance is a growing global problem. Antimicrobial stewardship programs aim to improve appropriate use of antimicrobials. Diagnostic testing plays an important role in these programs by identifying the microbes responsible for infections so patients can be given the right treatment as quickly as possible. We aimed to obtain the perspective of healthcare professionals from six countries on the challenges of and ways to improve diagnostic testing and antimicrobial stewardship programs. We found that some of the greatest challenges were related to costs. Approximately one-third of participants said that antimicrobial stewardship initiatives were lacking investment (32.3%) and resourcing (40.3%). High rates of antimicrobial resistance were identified as the greatest barriers to appropriate antimicrobial use (52.0%). Participants said that diagnostic practices have a positive impact on decreasing antimicrobial resistance (70.3%) and improving patient outcomes (81.0%). Overall, we found that healthcare professionals consider diagnostic tests to be an important part of antimicrobial stewardship, but there are several barriers to their success, including patient/hospital costs, turnaround time of test results, resourcing, antimicrobial resistance, and education. To overcome these barriers, increased funding, education, and resourcing, regular guideline updates, and development of optimised testing algorithms may help to improve antimicrobial stewardship and ultimately decrease antimicrobial resistance.

The scope of the antimicrobial resistance challenge.

Each year, an estimated 7·7 million deaths are attributed to bacterial infections, of which 4.95 million are associated with drug-resistant pathogens, and 1·27 million are caused by bacterial pathogens resistant to the antibiotics available. Access to effective antibiotics when indicated prolongs life, reduces disability, reduces health-care expenses, and enables access to other life-saving medical innovations. Antimicrobial resistance undoes these benefits and is a major barrier to attainment of the Sustainable Development Goals, including targets for newborn survival, progress on healthy ageing, and alleviation of poverty. Adverse consequences from antimicrobial resistance are seen across the human life course in both health-care-associated and community-associated infections, as well as in animals and the food chain. The small set of effective antibiotics has narrowed, especially in resource-poor settings, and people who are very young, very old, and severely ill are particularly susceptible to resistant infections. This paper, the first in a Series on the challenge of antimicrobial resistance, considers the global scope of the problem and how it should be measured. Robust and actionable data are needed to drive changes and inform effective interventions to contain resistance. Surveillance must cover all geographical regions, minimise biases towards hospital-derived data, and include non-human niches.

Synergistic effects of ceftazidime/avibactam combined with meropenem in a murine model of infection with KPC-producing Klebsiella pneumoniae.

OBJECTIVES: The emergence and expansion of carbapenem-resistant Klebsiella pneumoniae infections is a concern due to the lack of 'first-line' antibiotic treatment options. The ceftazidime/avibactam is an important clinical treatment for carbapenem-resistant K. pneumoniae infections but there is an increasing number of cases of treatment failure and drug resistance. Therefore, a potential solution is combination therapies that result in synergistic activity against K. pneumoniae carbapenemase: producing K. pneumoniae (KPC-Kp) isolates and preventing the emergence of KPC mutants resistant to ceftazidime/avibactam are needed in lieu of novel antibiotics. METHODS: To evaluate their synergistic activity, antibiotic combinations were tested against 26 KPC-Kp strains. Antibiotic resistance profiles, molecular characteristics and virulence genes were investigated by susceptibility testing and whole-genome sequencing. Antibiotic synergy was evaluated by in vitro chequerboard experiments, time-killing curves and dose-response assays. The mouse thigh model was used to confirm antibiotic combination activities in vivo. Additionally, antibiotic combinations were evaluated for their ability to prevent the emergence of ceftazidime/avibactam resistant mutations of blaKPC. RESULTS: The combination of ceftazidime/avibactam plus meropenem showed remarkable synergistic activity against 26 strains and restored susceptibility to both the partnering antibiotics. The significant therapeutic effect of ceftazidime/avibactam combined with meropenem was also confirmed in the mouse model and bacterial loads in the thigh muscle of the combination groups were significantly reduced. Furthermore, ceftazidime/avibactam plus meropenem showed significant activity in preventing the occurrence of resistance mutations. CONCLUSIONS: Our results indicated that the combination of ceftazidime/avibactam plus meropenem offers viable therapeutic alternatives in treating serious infections due to KPC-Kp.

Antimicrobial resistance and the great divide: inequity in priorities and agendas between the Global North and the Global South threatens global mitigation of antimicrobial resistance.

To limit the catastrophic effects of the increasing bacterial resistance to antimicrobials on health, food, environmental, and geopolitical security, and ensure that no country or region is left behind, a coordinated global approach is required. In this Viewpoint, we argue that the diverging resource availabilities, needs, and priorities of the Global North and the Global South in terms of the actions required to mitigate the antimicrobial resistance pandemic are a direct threat to success. We argue that evidence suggests a need to prioritise and support infection prevention interventions (ie, clean water and safe sanitation, increased vaccine coverage, and enhanced infection prevention measures for food production in the Global South contrary to the focus on research and development of new antibiotics in the Global North) and to recalibrate global funding resources to address this need. We call on global leaders to redress the current response, which threatens mitigation of the antimicrobial resistance pandemic.

Global Epidemiology and Mechanisms of Resistance of Acinetobacter baumannii-calcoaceticus Complex.

Acinetobacter baumannii-calcoaceticus complex is the most commonly identified species in the genus Acinetobacter and it accounts for a large percentage of nosocomial infections, including bacteremia, pneumonia, and infections of the skin and urinary tract. A few key clones of A. baumannii-calcoaceticus are currently responsible for the dissemination of these organisms worldwide. Unfortunately, multidrug resistance is a common trait among these clones due to their unrivalled adaptive nature. A. baumannii-calcoaceticus isolates can accumulate resistance traits by a plethora of mechanisms, including horizontal gene transfer, natural transformation, acquisition of mutations, and mobilization of genetic elements that modulate expression of intrinsic and acquired genes.

Incidence of ESBLs and carbapenemases among Enterobacterales and carbapenemases in Pseudomonas aeruginosa isolates collected globally: results from ATLAS 2017-2019.

OBJECTIVES: To assess the global and regional distribution of ESBLs in Enterobacterales and carbapenemases in Enterobacterales and Pseudomonas aeruginosa. METHODS: Antimicrobial susceptibility of isolates collected from ATLAS (2017-2019) was determined per CLSI guidelines. Enterobacterales exhibiting meropenem MICs ≥2 mg/L and/or ceftazidime/avibactam and/or aztreonam/avibactam MICs ≥16 mg/L, Escherichia coli and Klebsiella pneumoniae with aztreonam and/or ceftazidime MICs ≥2 mg/L, and P. aeruginosa with meropenem MICs ≥4 mg/L were screened for ß-lactamases by PCR and sequencing. RESULTS: Globally, ESBL-positive E. coli (23.7%, 4750/20047) and K. pneumoniae (35.1%, 6055/17229) carried predominantly the CTX-M-15 variant (E. coli: 53.9%; K. pneumoniae: 80.0%) with highest incidence in Africa/Middle East (AfME). Among carbapenem-resistant (CR) E. coli (1.1%, 217/20047) and Enterobacter cloacae (3.8%, 259/6866), NDMs were predominant (E. coli in AfME: 62.5%; E. cloacae in Asia Pacific: 59.7%). CR K. pneumoniae (13.3%, 2299/17 229) and P. aeruginosa (20.3%, 4187/20 643) carried predominantly KPC (30.9%) and VIM (14.7%), respectively, with highest frequency in Latin America. Among ESBL-positive Enterobacterales, susceptibility to ceftazidime/avibactam (>90.0%) and amikacin (>85.0%) was higher than to piperacillin/tazobactam (>45.0%) and ciprofloxacin (>7.4%). In CR Enterobacterales, susceptibility to amikacin (>54.0%) and ceftazidime/avibactam (>31.0%) was higher than to ciprofloxacin (>2.7%) and piperacillin/tazobactam (>0.5%). CR P. aeruginosa similarly demonstrated higher susceptibility to amikacin (63.4%) and ceftazidime/avibactam (61.9%) than to ciprofloxacin (26.2%) and piperacillin/tazobactam (25.3%). CONCLUSIONS: Varied distribution of resistance genotypes across regions among ESBL-positive Enterobacterales and CR Enterobacterales and P. aeruginosa provide crucial insights on major resistance mechanisms and trends observed in recent years. Continued surveillance is warranted for monitoring global dissemination and resistance.

Molecular Mechanisms of Resistance to Ceftazidime/Avibactam in Clinical Isolates of Enterobacterales and Pseudomonas aeruginosa in Latin American Hospitals.

Ceftazidime-avibactam (CZA) is the combination of a third-generation cephalosporin and a new non-ß-lactam ß-lactamase inhibitor capable of inactivating class A, C, and some D ß-lactamases. From a collection of 2,727 clinical isolates of Enterobacterales (n = 2,235) and P. aeruginosa (n = 492) that were collected between 2016 and 2017 from five Latin American countries, we investigated the molecular resistance mechanisms to CZA of 127 (18/2,235 [0.8%] Enterobacterales and 109/492 [22.1%] P. aeruginosa). First, by qPCR for the presence of genes encoding KPC, NDM, VIM, IMP, OXA-48-like, and SPM-1 carbapenemases, and second, by whole-genome sequencing (WGS). From the CZA-resistant isolates, MBL-encoding genes were detected in all 18 Enterobacterales and 42/109 P. aeruginosa isolates, explaining their resistant phenotype. Resistant isolates that yielded a negative qPCR result for any of the MBL encoding genes were subjected to WGS. The WGS analysis of the 67 remaining P. aeruginosa isolates showed mutations in genes previously associated with reduced susceptibility to CZA, such as those involved in the MexAB-OprM efflux pump and AmpC (PDC) hyperproduction, PoxB (blaOXA-50-like), FtsI (PBP3), DacB (PBP4), and OprD. The results presented here offer a snapshot of the molecular epidemiological landscape for CZA resistance before the introduction of this antibiotic into the Latin American market. Therefore, these results serve as a valuable comparison tool to trace the evolution of the resistance to CZA in this carbapenemase-endemic geographical region. IMPORTANCE In this manuscript, we determine the molecular mechanisms of ceftazidime-avibactam resistance in Enterobacterales and P. aeruginosa isolates from five Latin American countries. Our results reveal a low rate of resistance to ceftazidime-avibactam among Enterobacterales; in contrast, resistance in P. aeruginosa has proven to be more complex, as it might involve multiple known and possibly unknown resistance mechanisms.

Virulence Profile, Antibiotic Resistance, and Phylogenetic Relationships among Escherichia coli Strains Isolated from the Feces and Urine of Hospitalized Patients.

Extra-intestinal pathogenic Escherichia coli (ExPEC) may inhabit the human gut microbiota without causing disease. However, if they reach extra-intestinal sites, common cystitis to bloodstream infections may occur, putting patients at risk. To examine the human gut as a source of endogenous infections, we evaluated the E. coli clonal diversity of 18 inpatients' guts and their relationship with strains isolated from urinary tract infection (UTI) in the same hospital. Random amplified polymorphic DNA evaluated the clonal diversity, and the antimicrobial susceptibility was determined by disk diffusion. One isolate of each clone detected was sequenced, and their virulome and resistome were determined. Overall, 177 isolates were screened, among which 32 clones were identified (mean of two clones per patient), with ExPEC strains found in over 75% of the inpatients' guts. Endogenous infection was confirmed in 75% of the cases. ST10, ST59, ST69, ST131, and ST1193 clones and critical mobile drug-resistance encoding genes (blaCTX-M-15, blaOXA-1, blaDHA-1, aac(6')-lb-cr, mcr-1.26, qnrB4, and qnrB19) were identified in the gut of inpatients. The genomic analysis highlighted the diversity of the fecal strains, colonization by lactose-negative E. coli, the high frequency of ExPEC in the gut of inpatients without infections, and the presence of ß-lactamase producing E. coli in the gut of inpatients regardless of the previous antibiotics' usage. Considering that we found more than one ExPEC clone in the gut of several inpatients, surveillance of inpatients' fecal pathogens may prevent UTI caused by E. coli in the hospital and dissemination of risk clones.

Molecular mechanisms leading to ceftolozane/tazobactam resistance in clinical isolates of Pseudomonas aeruginosa from five Latin American countries.

Objectives: Identify molecular mechanisms responsible for the in vitro non-susceptibility to ceftolozane/tazobactam (TOL) in a group of 158 clinical isolates of Pseudomonas aeruginosa from five Latin American countries collected before the introduction of TOL into the clinical practice. Methods: Clinical isolates of P. aeruginosa (n = 504) were collected between January 2016 and October 2017 from 20 hospitals located in Argentina, Brazil, Chile, Colombia, and Mexico. Minimum inhibitory concentrations (MICs) to TOL were determined by standard broth microdilution and interpreted according to CLSI breakpoints. Initially, production of carbapenemases in TOL non-susceptible isolates was assessed by Rapidec® followed by qPCR to detect bla KPC, bla NDM-1, bla VIM, and bla IMP. Illumina® WGS was performed for isolates in which non-susceptibility to TOL was not mediated by carbapenemases. Results: A total of 158 (31.3%) isolates were non-susceptible to TOL. In 74 (46.8%) of these isolates, non-susceptibility to TOL was explained by the production of at least one carbapenemase. WGS revealed that some isolates carried ESBLs, mutated bla PDC and ampD, associated with decreased susceptibility to TOL. Conclusion: Substitutions found in PDC and carbapenemase production were the most common presumed mechanisms of resistance to TOL detected in this study. This study shows that epidemiological surveillance is warranted to monitor the emergence of novel mechanisms of resistance to TOL that might compromise its clinical utility.

Comparative In Vitro Activity of Ceftolozane/Tazobactam against Clinical Isolates of Pseudomonas aeruginosa and Enterobacterales from Five Latin American Countries.

BACKGROUND: Ceftolozane/tazobactam (C/T) is a combination of an antipseudomonal oxyiminoaminothiazolyl cephalosporin with potent in vitro activity against Pseudomonas aeruginosa and tazobactam, a known ß-lactamase inhibitor. The aim of this study was to evaluate the activity of C/T against clinical isolates of P. aeruginosa and Enterobacterales collected from five Latin American countries between 2016 and 2017, before its clinical use in Latin America, and to compare it with the activity of other available broad-spectrum antimicrobial agents. METHODS: a total of 2760 clinical isolates (508 P. aeruginosa and 2252 Enterobacterales) were consecutively collected from 20 hospitals and susceptibility to C/T and comparator agents was tested and interpreted following the current guidelines. RESULTS: according to the CLSI breakpoints, 68.1% (346/508) of P. aeruginosa and 83.9% (1889/2252) of Enterobacterales isolates were susceptible to C/T. Overall, C/T demonstrated higher in vitro activity than currently available cephalosporins, piperacillin/tazobactam and carbapenems when tested against P. aeruginosa, and its performance in vitro was comparable to fosfomycin. When tested against Enterobacterales, it showed higher activity than cephalosporins and piperacillin/tazobactam, and similar activity to ertapenem. CONCLUSIONS: these results show that C/T is an active ß-lactam agent against clinical isolates of P. aeruginosa and Enterobacterales.

Diversity of lytic bacteriophages against XDR Klebsiella pneumoniae sequence type 16 recovered from sewage samples in different parts of the world.

Bacteriophages (phages) are viruses considered to be natural bacterial predators and widely detected in aquatic environments. Sewage samples are an important source of phage isolation since high density and diversity of bacterial cells are present, due to human, animal and household fluids. This study aims to investigate and characterise phages against an extremely drug-resistant (XDR) lineage, Klebsiella pneumoniae ST16, using sewage samples from different parts of the World. Sewage samples from Brazil, Bangladesh, Saudi Arabia, Thailand and the United Kingdom were collected and used to investigate phages against ten K. pneumoniae ST16 (hosts) recovered from infection sites. The phages were microbiological and genetically characterised by double-agar overlay (DLA), transmission electron microscopy and Illumina WGS. The host range against K. pneumoniae belonging to different sequence types was evaluated at different temperatures by spot test. Further phage characterisation, such as efficiency of plating, optimal phage temperature, and pH/temperature susceptibility, were conducted. Fourteen lytic phages were isolated, belonging to Autographiviridae, Ackermannviridae, Demerecviridae, Drexlerviridae, and Myoviridae families, from Brazil, Bangladesh, Saudi Arabia and Thailand and demonstrated a great genetic diversity. The viruses had good activity against our collection of clinical K. pneumoniae ST16 at room temperature and 37 °C, but also against other important Klebsiella clones such as ST11, ST15, and ST258. Temperature assays showed lytic activity in different temperatures, except for PWKp18 which only had activity at room temperature. Phages were stable between pH 5 and 10 with minor changes in phage activity, and 70 °C was the temperature able to kill all phages in this study. Using sewage from different parts of the World allowed us to have a set of highly efficient phages against an K. pneumoniae ST16 that can be used in the future to develop new tools to combat infections in humans or animals caused by this pathogen.

Unravelling complex transposable elements surrounding blaGES-16 in a Pseudomonas aeruginosa ExoU strain.

OBJECTIVES: We characterised the complex surrounding regions of blaGES-16 in a Pseudomonas aeruginosa exoU+ strain (P-10.226) in Brazil. METHODS: Species identification was performed by MALDI-TOF MS, and the antimicrobial susceptibility profile was determined by broth microdilution based on European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. The whole genome sequencing (WGS) of P-10.226 strain was performed using both short-read paired-end sequencing on the Illumina MiSeq platform as well as the long-read Oxford Nanopore MinION. RESULTS: WGS analysis showed that P-10.226 carried blaGES-16, which was found as a gene cassette inserted into a novel class I integron, In1992 (aadB-blaOXA-56-blaGES-16-aadB-aadA6c), whose 3'-CS was truncated by a nested transposable element, IS5564::ISPa157. The structure was even more complex since IS6100-ΔIS6100 structure and a TnAs2-like harbouring the operon merRTPADE was found downstream In1992. Fragments of TnAs3 harbouring 25-bp imperfect inverted repeats were identified bordering the intl1 of In1992 and also flanking IS6100-ΔIS6100, which might be genetic marks of its previous presence in the genome. Interestingly, In1992 also shows a distinct cassette array from In581 (blaGES-16-dfrA22-aacA27-aadA1), which was previously reported in Serratia marcescens strains recovered in Brazil. Finally, exoU gene, which encodes a potent cytotoxin of type III secretion systems (T3SS) effector proteins from P. aeruginosa and is associated to severe infections, was also detected. CONCLUSION: We described the novel In1992 carrying blaGES-16 surrounded by complex transposition events in a XDR P. aeruginosa strain. The identification of many sets of direct repeats adjacent to TnAs3 fragments indicates a major past of transposition events that shaped the current genetic environment of In1992.

Role of ISKpn23 in blaBKC-1 Expression and Mobilization.

This study aimed to verify the role of ISKpn23 in the expression and mobilization of blaBKC-1 and aph(3')-VIi. Five constructs related to the natural blaBKC-1 genetic background in plasmid p60136 were made and submitted for antimicrobial susceptibility testing and quantitative reverse transcription-PCR. Transposition of ISKpn23-blaBKC-1 was investigated using transposition assays involving a 9.7-kb nonconjugative plasmid carrying blaBKC-1 (p60136) and a transfer-proficient plasmid (pOX38-Gen). The presence of ISKpn23 had a crucial role in blaBKC-1 expression, resulting in increased ß-lactam MICs. While we detected mobilization of p60136 by the pOX38-Gen plasmid, transposition of ISKpn23-blaBKC-1 was not observed.

Effective phage cocktail to combat the rising incidence of extensively drug-resistant Klebsiella pneumoniae sequence type 16.

Bacteriophages are the most abundant organisms on Earth. As there are few effective treatment options against some pathogens, the interest in the bacteriophage control of multi-drug-resistant bacterial pathogens is escalating, especially for Klebsiella pneumoniae. This study aimed to develop a phage-based solution to the rising incidence of extensively drug-resistant clinical Klebsiella pneumoniae sequence type (ST16) infections starting from a set of phages recently characterized against this lineage. A phage-cocktail (Katrice-16) composed of eight lytic phages was characterized for potential use in humans. In vitro and in vivo broth inhibition and Galleria mellonella rescue assays were used to demonstrate the efficacy of this approach using a collection of 56 strains of K. pneumoniae ST16, with distinct genetic backgrounds that were collected from clinical infections from four disparate nations. Additionally, Katrice-16 anti-biofilm activity, synergism with meropenem, and activity in human body fluids were also assessed. Katrice-16 was highly active in vitro against our K. pneumoniae ST16 collection (AUC% median = 86.48%; Q1 = 83.8%; Q2 = 96.85%; Q3 = 98.85%). It additionally demonstrated excellent in vivo activity in G. mellonella rescue assays, even with larvae infected by isolates that exhibited moderate in vitro inhibition. We measured significant anti-biofilm activity over 12 h (p = .0113) and synergic activity with meropenem. In addition, we also demonstrate that Katrice-16 maintained high activity in human body fluids. Our results indicate that our cocktail will likely be an effective solution for human infections with this increasingly prevalent and often highly resistant bacterial clone.

Silent circulation of BKC-1-producing Klebsiella pneumoniae ST442: molecular and clinical characterization of an early and unreported outbreak.

OBJECTIVE: To describe the undetected circulation of an epidemic BKC-1-producing Klebsiella pneumoniae ST442 clone, occasioning the first reported outbreak of the infrequent carbapenemase BKC-1. METHODS: Six hundred and forty-seven K. pneumoniae isolates (2008-2017) with reduced susceptibility to carbapenems were screened for blaBKC-1. BKC-1-positive isolates were typed using pulsed-field gel electrophoresis and multi-locus sequence typing. Susceptibility profiles were determined by broth microdilution, and additional antimicrobial resistance genes (ARGs) were investigated by polymerase chain reaction. Some isolates were submitted to full genomic characterization by whole-genome sequencing (Illumina MiSeq and MinIon), and in-vivo virulence studies using the Galleria mellonella model. RESULTS: Sixteen (2.5%) K. pneumoniae, from 15 patients, carrying blaBKC-1 were found between 2010 and 2012. Among these patients, the all-cause mortality rate was 54.5%. A major clone - A1-ST442 (13/16) - was isolated during the study period. The BKC-1-producing isolates had a multi-drug-resistant phenotype, remaining susceptible to gentamicin (87.5%) and ceftazidime-avibactam (100%) alone. The presence of two carbapenemases - blaBKC-1 and blaKPC-2 - was detected in six isolates, increasing the ß-lactam minimum inhibitory concentration significantly. Additionally, other ARGs were identified on A1-ST442 and B1-ST11 clones. The B1-ST11 clone was more virulent than the A1-ST442 clone. CONCLUSION: An undetected outbreak caused predominantly by a BKC-1-positive A1-ST442 clone between 2010 and 2012 was identified 10 years later in a Brazilian hospital. The misidentification of BKC-1 may have worsened the spread of resistant clones; this reinforces the need for correct and rapid identification of antimicrobial resistance mechanisms in hospitals.

Genomic analyses of ciprofloxacin-resistant Neisseria gonorrhoeae isolates recovered from the largest South American metropolitan area.

We sequenced 13 Neisseria gonorrhoeae isolates exhibiting distinct susceptibility profiles and which were recovered over 12 years in the metropolitan region of São Paulo, Brazil. Whole Genome Sequencing (WGS) was performed on an Illumina MiSeq™ 2 × 300 bp paired-end reads. Bioinformatics analyses were carried out using CGE, PATRIC, and BLAST databases for manual curation of obtained genomes. Multilocus sequence typing (MLST) analysis identified seven STs, namely ST1580, ST1590, ST1901, ST1902, ST8161, ST9363, and ST15640. Moreover, a diversity of mutations was observed in MtrR/G45D-A39T, PIB/G120K-A121S, and PBP1/L421P. Mutations associated with sulfonamides (DHPS/R228S) and rifampicin (RNAP/H552N) were also detected, as well as tetracycline resistance determinants, namely rpsJ/V57M and tet(M). The results presented herein can contribute to the knowledge of N. gonorrhoeae strains circulating in Sao Paulo, Brazil.

Characterization of Amino Acid Substitution W20S in MgrB Involved in Polymyxin Resistance in Klebsiella pneumoniae.

In the major human pathogen Klebsiella pneumoniae, MgrB inactivation by disruptive insertion sequence (IS) elements and mutations leading to early termination are known to play an important role in polymyxin resistance. In this study, we examined a collection of invasive blaKPC-2-producing K. pneumoniae isolates belonging to the high-risk clone sequence type 258 (ST258) displaying high rates of resistance to many antimicrobials, including polymyxins. We identified a deleterious substitution (W20S) in MgrB and confirmed by genetic complementation analysis that this variant was inactive, leading to increased polymyxin B and colistin MICs. IMPORTANCE Carbapenem-resistant Gram-negative bacteria are designated critical pathogens by the World Health Organization. Polymyxins (i.e., polymyxin B and colistin) are last-resort antibiotics and particularly useful against these multidrug-resistant bacteria. In Klebsiella pneumoniae, the inactivation of MgrB, a negative regulator of PhoPQ, was shown to be the major pathway leading to colistin resistance. While gene disruption by insertion sequence (IS) elements and mutations leading to early termination (stop codons) are frequent, deleterious mutations are not observed frequently and have not been characterized. Here, we identified a deleterious substitution (W20S) in MgrB among a collection of bloodstream infection, blaKPC-2-producing K. pneumoniae sequence type 258 (ST258) isolates, displaying high rates of resistance to polymyxins and associated with a high mortality rate. The dissemination of such a MgrB-W20S mutation leading to polymyxin resistance within the ST258 high-risk clone background is problematic and thus warrants particular attention.

A global perspective on improving patient care in uncomplicated urinary tract infection: expert consensus and practical guidance.

OBJECTIVES: Uncomplicated urinary tract infections (uUTIs) are a common problem in female patients. Management is mainly based on empirical prescribing, but there are concerns about overtreatment and antimicrobial resistance (AMR), especially in patients with recurrent uUTIs. METHODS: A multidisciplinary panel of experts met to discuss diagnosis, treatment, prevention, guidelines, AMR, clinical trial design and the impact of COVID-19 on clinical practice. RESULTS: Symptoms remain the cornerstone of uUTI diagnosis, and urine culture is necessary only when empirical treatment fails or rapid recurrence of symptoms or AMR is suspected. Specific antimicrobials are first-line therapy (typically nitrofurantoin, fosfomycin, trimethoprim/sulfamethoxazole and pivmecillinam, dependent on availability and local resistance data). Fluoroquinolones are not first-line options for uUTIs primarily due to safety concerns but also rising resistance rates. High-quality data to support most non-antimicrobial approaches are lacking. Local AMR data specific to community-acquired uUTIs are needed, but representative information is difficult to obtain; instead, identification of risk factors for AMR can provide a basis to guide empirical antimicrobial prescribing. The COVID-19 pandemic has impacted the management of uUTIs in some countries and may have long-lasting implications for future models of care. CONCLUSION: Management of uUTIs in female patients can be improved without increasing complexity, including simplified diagnosis and empirical antimicrobial prescribing based on patient characteristics, including a review of recent antimicrobial use and past pathogen resistance profiles, drug availability and guidelines. Current data for non-antimicrobial approaches are limited. The influence of COVID-19 on telehealth could provide an opportunity to enhance patient care in the long term.

Broad-spectrum antimicrobial consumption trends and correlation with bacterial infections and antimicrobial resistance over 5 years.

OBJECTIVES: Consumption trends of four broad-spectrum antimicrobials and their correlation with antimicrobial resistance in Gram-negative bacilli (GNB) from 2013-2017 within intensive care units (ICUs) were explored. METHODS: Consumption of meropenem (MEM), polymyxin B (PMB), piperacillin/tazobactam (TZP) and cefepime (FEP) in defined daily doses per 1000 patient-days (DDD/1000PD) was measured. Infection-related GNB isolates were grouped according to specific resistance profiles. Time series of antimicrobial consumption and their parametric correlation with each grouped resistant GNB were explored. RESULTS: A total of 1423 GNB were evaluated. A significant linear decline in consumption was observed for MEM [slope -3.88, 95% confidence interval (CI) -4.96 to -2.81; P < 0.0001] and PMB (slope -3.51, 95% CI -5.528 to -1.495; P = 0.0009). A significant decline in MEM-non-susceptible Acinetobacter spp. (R2 = 0.476; P = 0.006) and an increase in FEP-non-susceptible Escherichia coli (R2 = 0.124; P = 0.006) was observed. A significant correlation between MEM consumption and MEM-non-susceptible Acinetobacter spp. (r = 0.43; P = 0.001) was observed. MEM consumption and MEM-non-susceptible Acinetobacter spp. showed a positive correlation. CONCLUSION: Reduction in the consumption of broad-spectrum antimicrobials may alter the frequency of infection-related isolates and their antimicrobial resistance profiles.