Detection of polymyxins resistance among Enterobacterales: evaluation of available methods and proposal of a new rapid and feasible methodology.

BACKGROUND: Fast and accurate detection of polymyxins resistance is necessary as they remain the last resources to treat infections caused by Carbapenem-resistant Enterobacterales in many regions. We evaluated the rapid colorimetric polymyxin B elution (RCPE) and developed its miniaturized version, RCPE microelution (RCPEm), aiming to detect polymyxins resistance among Enterobacterales. METHODS: The methodologies consist of exposing the bacterial population in a solution (NP solution) where polymyxin B disks were previously eluted to obtain a concentration of 2 µg/mL for RCPE and 3 µg/mL for RCPEm. RESULTS: Two hundred sixty-seven Enterobacterales were evaluated, 90 (33.7%) resistant to polymyxin B by broth microdilution. It was observed 0.6% of major error (ME) by RCPE, with a specificity of 99.4%. The miniaturized version (RCPEm) presented the same ME and specificity values, but slightly higher sensitivity (97.8% vs. 95.6%) with 2.2% of very major error (VME). CONCLUSIONS: RCPE and RCPEm proved to be useful alternatives to determine polymyxin B susceptibility in clinical microbiology laboratories, presenting low cost, being easy to perform, and demanding short incubation time.

Community-acquired and healthcare-associated Staphylococcus aureus infections in a pediatric hospital in southern Brazil over 8 years: how common is MRSA?

Backgrounds: Both healthcare-associated and community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are relevant in children. The objective of our study was to evaluate their impact in a pediatric hospital in southern Brazil. Methods: Data from patients under 18 years of age with S. aureus infections between January 2013 and December 2020 were retrospectively analyzed. Data were collected regarding infection site, infection type (community-acquired or healthcare-associated), susceptibility to oxacillin [methicillin-susceptible S. aureus (MSSA) or MRSA] and other antimicrobials. We analyzed the evolution of the susceptibility rates for the isolates over this period. Results: A total of 563 patients were included, among whom the prevalences of community- and hospital-acquired MRSA infections were 46.1% and 8.1%, respectively. No significant change occurred in these prevalences over the study period. In community-acquired infections, MSSA was significantly more associated with osteoarticular infections and MRSA was more associated with respiratory and intra-abdominal infections. In healthcare-associated infections, there was an association between MSSA and primary bloodstream infections and between MRSA, skin/soft tissue infections, and respiratory infections. Community-acquired MRSA were highly susceptible to trimethoprim-sulfamethoxazole (96.1%), clindamycin (88.4%), and doxycycline (99.0%). Conclusion: Our study draws attention to the high rates of MRSA in community-acquired staphylococcal infections in this population, indicating a need to review initial protocols for severe staphylococcal infections according to local epidemiology.

Colistin resistance in Escherichia coli and Klebsiella pneumoniae in humans and backyard animals in Ecuador.

Objective: Colistin is an antibiotic of last resort for treating serious Gram-negative bacterial infections. However, the misuse of colistin, especially as an animal growth promoter, has contributed to increasing antimicrobial resistance, mediated mainly through plasmid transfer of the mcr-1 gene. This study assessed the prevalence of phenotypic and molecular colistin resistance in Escherichia coli and Klebsiella pneumoniae in Ecuador in healthy humans and their chickens and pigs. Methods: Fecal samples were collected from humans and their chickens and pigs in two rural coastal and Amazon regions between April and August 2020. Gram-negative bacteria were isolated and identified using conventional techniques. Phenotypic resistance was determined using the broth microdilution technique, and the mcr-1 gene was detected using conventional polymerase chain reaction. Results: A total of 438 fecal samples were obtained from 137 humans, 147 pigs and 154 chickens. The prevalence of E. coli isolates was 86.3% (378/438) and K. pneumoniae, 37.4% (164/438). Overall, the mcr-1 gene was found in 90% (340/378) of E. coli isolates, with higher prevalences found in isolates from coastal regions (96.5%, 191/198), humans (95.6%, 111/116) and chickens (91.8%, 123/134); for K. pneumoniae, the gene was found in 19.5% (32/164) of isolates, with equal distribution between regions and hosts. Only four isolates, two E. coli and two K. pneumoniae, showed phenotypic resistance: mcr-1 was present in both E. coli strains but absent in the K. pneumoniae strains. Conclusions: Despite a low prevalence of phenotypic resistance to colistin, the high prevalence of the mcr-1 gene in E. coli is of concern. Ecuador's ban on using colistin in animal husbandry must be enforced, and continual monitoring of the situation should be implemented.

Whole-genome sequencing for surveillance of antimicrobial resistance in Ecuador: present and future implications.

Whole-genome sequencing is becoming the gold standard for pathogen characterization and offers considerable advantages for understanding the evolution and dissemination of new determinants of antimicrobial resistance. Despite the benefits of whole-genome sequencing for pathogen characterization, implementation costs and lack of expertise may limit its use by public health laboratories. This article reviews the advantages of whole-genome sequencing for pathogen characterization and the current status of the use of whole-genome sequencing for antimicrobial resistance surveillance in Ecuador. A roadmap is suggested for including whole-genome sequencing for pathogen characterization based on the needs of the health reference institutions through alliances with Ecuadorian universities. Establishing a partnership between public health institutions and academia would be valuable for clinicians, policy-makers, and epidemiologists who could then take reasonable measures in those areas and establish a basis for adapting One Health strategies to tackle antimicrobial resistance in Ecuador.

La secuenciación del genoma completo, que está pasando a ser el estándar de referencia para la caracterización de agentes patógenos, ofrece ventajas considerables para comprender la evolución y la diseminación de los nuevos determinantes de la resistencia a los antimicrobianos. Sin embargo, a pesar de los beneficios que genera, los costos de ejecución y la falta de experiencia pueden limitar su uso por parte de los laboratorios de salud pública. En este artículo se evalúan las ventajas de la secuenciación del genoma completo para la caracterización de agentes patógenos y el estado actual del uso de la secuenciación del genoma completo en la vigilancia de la resistencia a los antimicrobianos en Ecuador. Se propone una hoja de ruta para incluir la secuenciación del genoma completo para la caracterización de agentes patógenos según las necesidades de las instituciones de salud de referencia, lo que se haría por medio de alianzas con universidades ecuatorianas. Establecer una asociación entre las instituciones de salud pública y los círculos académicos sería sumamente valioso para los médicos, los responsables de las políticas y los epidemiólogos, que podrían adoptar medidas razonables en sus ámbitos y sentar una base para adaptar las estrategias de "Una salud" a fin de abordar la resistencia a los antimicrobianos en Ecuador.

O sequenciamento do genoma completo está se tornando o padrão ouro para a caracterização de patógenos e oferece vantagens consideráveis para a compreensão da evolução e disseminação de novos determinantes de resistência aos antimicrobianos. Apesar dos benefícios do sequenciamento do genoma completo para a caracterização de patógenos, os custos de implementação e a falta de especialização podem limitar seu uso pelos laboratórios de saúde pública. Este artigo analisa as vantagens do sequenciamento do genoma completo para a caracterização de patógenos e a situação atual do uso desta técnica para a vigilância da resistência aos antimicrobianos no Equador. Sugere-se um roteiro para incluir o sequenciamento de genomas completos para caracterização de patógenos com base nas necessidades das instituições de saúde de referência, por meio de alianças com universidades equatorianas. A criação de uma parceria entre instituições de saúde pública e entidades acadêmicas seria valiosa para clínicos, formuladores de políticas e epidemiologistas, que poderiam, assim, tomar medidas razoáveis nessas áreas e estabelecer uma base para adaptar estratégias de Saúde Única para combater a resistência aos antimicrobianos no Equador.

Epidemiology and risk factors for mortality among methicillin-resistant Staphylococcus aureus bacteremic patients in Southern Brazil.

This study aimed to evaluate the epidemiology and 30-day mortality of adult patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. We retrospectively reviewed the demographic and clinical data of adult patients with S. aureus bloodstream infections (BSI), admitted to a tertiary public teaching medical center in Porto Alegre, Southern Brazil, from January 2014 to December 2019. A total of 928 patients with S. aureus BSI were identified in the study period (68.5 per 100,000 patient-years), and the proportion of MRSA isolates was 22% (19-27%). Thus, 199 patients were included in the analyses. The median age was 62 (IQR: 51-74) years, Charlson Comorbidity Index (CCI) median was 5 (IQR: 3-6), the Pitt bacteremia score (PBS) median was 1 (IQR: 1-4), and the most common site of infection was skin and soft tissue (26%). Most infections were hospital-acquired (54%), empirical anti-MRSA treatment was initiated in 34% of the cases, and in 44% vancomycin minimum inhibitory concentration was 1.5mg/L or above. Sixty-two (31.2%) patients died up to 30 days after the bacteremia episode. Patients with more comorbid conditions (higher CCI; aOR 1.222, p = 0.006) and a more severe presentation (higher PBS; aOR 1.726, p<0.001) were independently associated with mortality. Empiric antimicrobial therapy with an anti-MRSA regimen was associated with reduced mortality (aOR 0.319, p = 0.016). Our study identified significant risk factors for 30-day mortality in patients with MRSA BSI in a population with a high incidence of S. aureus bacteremia. Empiric treatment with an anti-MRSA drug was a protective factor. No significant variation in the incidence of S. aureus BSI was recorded throughout the period.

Streptococcus pneumoniae serotype 19A from carriers and invasive disease: virulence gene profile and pathogenicity in a Galleria mellonella model.

PURPOSE: This study aimed to evaluate and compare the presence of genes related to surface proteins between isolates of Streptococcus pneumoniae from healthy carriers (HC) and invasive pneumococcal disease (IPD) with a particular focus on serotype 19A. METHODS: The presence of these genes was identified by real-time PCR. Subsequently, we employed the Galleria mellonella larval infection model to study their effect on pathogenicity in vivo. RESULTS: The percentage of selected virulence genes was similar between the HC and IPD groups (p > 0.05), and the genes lytA, nanB, pavA, pcpA, phtA, phtB, phtE, rrgA, and sipA were all present in both groups. However, the virulence profile of the isolates differed individually between HC and IPD groups. The highest lethality in G. mellonella was for IPD isolates (p < 0.01), even when the virulence profile was the same as compared to the HC isolates or when the nanA, pspA, pspA-fam1, and pspC genes were not present. CONCLUSIONS: The occurrence of the investigated virulence genes was similar between HC and IPD S. pneumoniae serotype 19A groups. However, the IPD isolates showed a higher lethality in the alternative G. mellonella model than the HC isolates, regardless of the virulence gene composition, indicating that other virulence factors may play a decisive role in virulence. Currently, this is the first report using the in vivo G. mellonella model to study the virulence of clinical isolates of S. pneumoniae.

Staphylococcus argenteus Infections, Brazil.

In 2015, two new species related to the Staphylococcus aureus were proposed. We describe five isolates of the new species Staphylococcus argenteus cultured from human cases of bacteremia and skin and soft tissue infections. This is the first report of S. argenteus, from South America, causing community-acquired and nosocomial infections.

Colistin resistance in Escherichia coli and Klebsiella pneumoniae in humans and backyard animals in Ecuador / Resistencia a la colistina de las bacterias Escherichia coli y Klebsiella pneumoniae en humanos y animales de granja en Ecuador / Resistência à colistina em Escherichia coli e Klebsiella pneumoniae em humanos e animais de quintal no Equador

ABSTRACT Objective. Colistin is an antibiotic of last resort for treating serious Gram-negative bacterial infections. However, the misuse of colistin, especially as an animal growth promoter, has contributed to increasing antimicrobial resistance, mediated mainly through plasmid transfer of the mcr-1 gene. This study assessed the prevalence of phenotypic and molecular colistin resistance in Escherichia coli and Klebsiella pneumoniae in Ecuador in healthy humans and their chickens and pigs. Methods. Fecal samples were collected from humans and their chickens and pigs in two rural coastal and Amazon regions between April and August 2020. Gram-negative bacteria were isolated and identified using conventional techniques. Phenotypic resistance was determined using the broth microdilution technique, and the mcr-1 gene was detected using conventional polymerase chain reaction. Results. A total of 438 fecal samples were obtained from 137 humans, 147 pigs and 154 chickens. The prevalence of E. coli isolates was 86.3% (378/438) and K. pneumoniae, 37.4% (164/438). Overall, the mcr-1 gene was found in 90% (340/378) of E. coli isolates, with higher prevalences found in isolates from coastal regions (96.5%, 191/198), humans (95.6%, 111/116) and chickens (91.8%, 123/134); for K. pneumoniae, the gene was found in 19.5% (32/164) of isolates, with equal distribution between regions and hosts. Only four isolates, two E. coli and two K. pneumoniae, showed phenotypic resistance: mcr-1 was present in both E. coli strains but absent in the K. pneumoniae strains. Conclusions. Despite a low prevalence of phenotypic resistance to colistin, the high prevalence of the mcr-1 gene in E. coli is of concern. Ecuador's ban on using colistin in animal husbandry must be enforced, and continual monitoring of the situation should be implemented.

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RESUMO Objetivo. A colistina é um antibiótico de último recurso para o tratamento de infecções graves por bactérias Gram-negativas. Entretanto, o uso indevido da colistina, principalmente como promotor de crescimento animal, tem contribuído para o aumento da resistência a antimicrobianos, principalmente por transferência horizontal do gene mcr-1 mediada por plasmídeos. Este estudo avaliou a prevalência de resistência fenotípica e molecular à colistina em Escherichia coli e Klebsiella pneumoniae no Equador em humanos hígidos e em galinhas e porcos por eles criados. Métodos. Entre abril e agosto de 2020, foram coletadas amostras de fezes de habitantes de duas regiões litorâneas e amazônicas do Equador e de galinhas e porcos por eles criados. Bactérias Gram-negativas foram isoladas e identificadas por meio de técnicas convencionais. A resistência fenotípica foi determinada pela técnica de microdiluição em caldo, e o gene mcr-1 foi detectado por reação em cadeia da polimerase convencional. Resultados. Foram obtidas 438 amostras fecais de 137 humanos, 147 suínos e 154 galinhas. A prevalência de isolados de E. coli foi de 86,3% (378/438), e de K. pneumoniae, 37,4% (164/438). Em geral, o gene mcr-1 foi encontrado em 90% (340/378) dos isolados de E. coli, com maiores prevalências encontradas em isolados de regiões litorâneas (96,5%, 191/198), humanos (95,6%, 111/116) e galinhas (91,8%, 123/134); para K. pneumoniae, o gene foi encontrado em 19,5% (32/164) dos isolados, com igual distribuição entre regiões e hospedeiros. Somente quatro isolados, dois de E. coli e dois de K. pneumoniae, demonstraram resistência fenotípica: o gene mcr-1 estava presente em ambas as cepas de E. coli, mas ausente nas de K. pneumoniae. Conclusões. Apesar da baixa prevalência de resistência fenotípica à colistina, a alta prevalência do gene mcr-1 em E. coli é preocupante. É preciso fiscalizar a proibição ao uso agropecuário de colistina no Equador e implementar o monitoramento contínuo da situação.

Whole-genome sequencing for surveillance of antimicrobial resistance in Ecuador: present and future implications / Secuenciación del genoma completo para la vigilancia de la resistencia a los antimicrobianos en Ecuador: implicaciones actuales y futuras / Sequenciamento do genoma completo para vigilância da resistência aos antimicrobianos no Equador: implicações presentes e futuras

ABSTRACT Whole-genome sequencing is becoming the gold standard for pathogen characterization and offers considerable advantages for understanding the evolution and dissemination of new determinants of antimicrobial resistance. Despite the benefits of whole-genome sequencing for pathogen characterization, implementation costs and lack of expertise may limit its use by public health laboratories. This article reviews the advantages of whole-genome sequencing for pathogen characterization and the current status of the use of whole-genome sequencing for antimicrobial resistance surveillance in Ecuador. A roadmap is suggested for including whole-genome sequencing for pathogen characterization based on the needs of the health reference institutions through alliances with Ecuadorian universities. Establishing a partnership between public health institutions and academia would be valuable for clinicians, policy-makers, and epidemiologists who could then take reasonable measures in those areas and establish a basis for adapting One Health strategies to tackle antimicrobial resistance in Ecuador.

RESUMEN La secuenciación del genoma completo, que está pasando a ser el estándar de referencia para la caracterización de agentes patógenos, ofrece ventajas considerables para comprender la evolución y la diseminación de los nuevos determinantes de la resistencia a los antimicrobianos. Sin embargo, a pesar de los beneficios que genera, los costos de ejecución y la falta de experiencia pueden limitar su uso por parte de los laboratorios de salud pública. En este artículo se evalúan las ventajas de la secuenciación del genoma completo para la caracterización de agentes patógenos y el estado actual del uso de la secuenciación del genoma completo en la vigilancia de la resistencia a los antimicrobianos en Ecuador. Se propone una hoja de ruta para incluir la secuenciación del genoma completo para la caracterización de agentes patógenos según las necesidades de las instituciones de salud de referencia, lo que se haría por medio de alianzas con universidades ecuatorianas. Establecer una asociación entre las instituciones de salud pública y los círculos académicos sería sumamente valioso para los médicos, los responsables de las políticas y los epidemiólogos, que podrían adoptar medidas razonables en sus ámbitos y sentar una base para adaptar las estrategias de "Una salud" a fin de abordar la resistencia a los antimicrobianos en Ecuador.

RESUMO O sequenciamento do genoma completo está se tornando o padrão ouro para a caracterização de patógenos e oferece vantagens consideráveis para a compreensão da evolução e disseminação de novos determinantes de resistência aos antimicrobianos. Apesar dos benefícios do sequenciamento do genoma completo para a caracterização de patógenos, os custos de implementação e a falta de especialização podem limitar seu uso pelos laboratórios de saúde pública. Este artigo analisa as vantagens do sequenciamento do genoma completo para a caracterização de patógenos e a situação atual do uso desta técnica para a vigilância da resistência aos antimicrobianos no Equador. Sugere-se um roteiro para incluir o sequenciamento de genomas completos para caracterização de patógenos com base nas necessidades das instituições de saúde de referência, por meio de alianças com universidades equatorianas. A criação de uma parceria entre instituições de saúde pública e entidades acadêmicas seria valiosa para clínicos, formuladores de políticas e epidemiologistas, que poderiam, assim, tomar medidas razoáveis nessas áreas e estabelecer uma base para adaptar estratégias de Saúde Única para combater a resistência aos antimicrobianos no Equador.

Extended-Spectrum Beta-Lactamases Producing Escherichia coli in South America: A Systematic Review with a One Health Perspective.

Purpose: Extended-spectrum beta-lactamase-producing (ESBL) Enterobacteriaceae, which includes Escherichia coli, has emerged as a global health threat. ESBL enzymes including CTX-M, TEM, and SHV are the most detected. Here, a systematic review was developed to assess the status of ESBLs in E. coli considering studies performed in the human, animal, food, and environmental realms in South America. Methods: Following PRISMA guidelines, a systematic review was performed using the PubMed database as a primary source to identify studies containing data on ESBL-producing E. coli in South America. To obtain a comprehensive sample, studies in English, Spanish, and Portuguese were included from 1990 to April 2021. Inclusion such as the reporting of sample origin and diagnostic method and exclusion criteria such as review/letter articles were established to complete data extraction steps. Results: Amongst 506 articles retrieved, 130 met the inclusion criteria. Brazil reported 65 (50%) of publications, followed by Argentina, and Ecuador with 11.5% each. According to the category of studies, human studies represented the 56%, animals the 20%, environmental the 11%, and food studies the 6%. Interestingly, studies assessing more than one category (ie, interdisciplinary) represented the 7%. Prevalence of ESBL producing E. coli in animal, food, and environmental studies was widely superior compared to human sources. In clinical studies, Brazil presented the greatest diversity in terms of ESBLs, featuring CTX-M, TEM, SHV, TOHO, OXA, and AmpC. CTX-M enzymes were the most frequent variants with 89.4% detections. Conclusion: The present One Health review of 130 studies conducted over the past 21 years found ESBLs producing E. coli distributed across human, animal, food, and environmental samples across South America. There is a need to increment studies in underrepresented countries and to strengthen multi-sectoral antimicrobial resistance research and surveillance. This information can be used as basis for subsequent implementation of monitoring programs, targeting potential critical points of transmission sources.

Etiology of meningitis among adults in three quaternary hospitals in Mozambique, 2016-2017: The role of HIV.

BACKGROUND: Meningitis remains an important cause of morbi-mortality in adults in sub-Saharan Africa. Data on the etiological investigation of meningitis in adults in Mozambique is limited and most studies were conducted in southern Mozambique. Identification of the etiology of meningitis in adults are crucial to guide prevention and treatments strategies. In this study, we determine the burden of fungal and bacterial meningitis among adults at the three largest hospitals in Mozambique. METHOD: We performed analysis of data from the routine sentinel surveillance system for meningitis in Mozambique from January 2016 to December 2017. Cerebrospinal fluid (CSF) samples were collected from eligible adults (≥18 years old) who met World Health Organization (WHO) case definition criteria for Meningitis. All samples were tested by cryptococcal antigen (CrAg) lateral flow assay (LFA), culture and triplex real-time polymerase chain reaction (qPCR) assay and all patients were tested for human immunodeficiency virus (HIV) using the national algorithm for HIV testing. RESULTS: Retrospective analysis of 1501 CSF samples from adults clinically suspected of meningitis revealed that 10.5% (158/1501) were positive for bacterial and fungal meningitis. Of these 158 confirmed cases, the proportion of Cryptococcal meningitis and pneumococcal meningitis was38.6% (95% CI: 31.0% to 46.7%) and 36.7% (95% CI: 29.2% to 44.7%), respectively. The other bacterial agents of meningitis identified include Neisseria meningitidis (8.9%; 14/158), Escherichia coli (6.3%; 10/158), Haemophilus influenzae (5.1%; 8/158) and S. aureus (4.4%; 7/158), which represent (24.7%; 39/158) of the total confirmed cases. CONCLUSION: Altogether, our findings show a high burden of Cryptococcal meningitis among adults in Mozambique, especially in people living with HIV, followed by pneumococcal meningitis. Our findings suggest that rollout of CrAg Lateral Flow Assay in the health system in Mozambique for early detection of cryptococcus neoformans is necessary to improve overall patient care.

Genomic insights of mcr-1 harboring Escherichia coli by geographical region and a One-Health perspective.

The importance of the One Health concept in attempting to deal with the increasing levels of multidrug-resistant bacteria in both human and animal health is a challenge for the scientific community, policymakers, and the industry. The discovery of the plasmid-borne mobile colistin resistance (mcr) in 2015 poses a significant threat because of the ability of these plasmids to move between different bacterial species through horizontal gene transfer. In light of these findings, the World Health Organization (WHO) recommends that countries implement surveillance strategies to detect the presence of plasmid-mediated colistin-resistant microorganisms and take suitable measures to control and prevent their dissemination. Seven years later, ten different variants of the mcr gene (mcr-1 to mcr-10) have been detected worldwide in bacteria isolated from humans, animals, foods, the environment, and farms. However, the possible transmission mechanisms of the mcr gene among isolates from different geographical origins and sources are largely unknown. This article presents an analysis of whole-genome sequences of Escherichia coli that harbor mcr-1 gene from different origins (human, animal, food, or environment) and geographical location, to identify specific patterns related to virulence genes, plasmid content and antibiotic resistance genes, as well as their phylogeny and their distribution with their origin. In general, E. coli isolates that harbor mcr-1 showed a wide plethora of ARGs. Regarding the plasmid content, the highest concentration of plasmids was found in animal samples. In turn, Asia was the continent that led with the largest diversity and occurrence of these plasmids. Finally, about virulence genes, terC, gad, and traT represent the most frequent virulence genes detected. These findings highlight the relevance of analyzing the environmental settings as an integrative part of the surveillance programs to understand the origins and dissemination of antimicrobial resistance.

A four-year follow-up survey of antimicrobial resistance among Acinetobacter baumannii complex from inpatients in Southern Brazil.

OBJECTIVES: To determine the trends of antimicrobial resistance for Acinetobacter baumannii complex isolates recovered from inpatients over a 4-year follow-up survey. METHODS: A total of 659 A baumannii complex isolates were recovered from hospitalized patients in Porto Alegre and its metropolitan area, Southern Brazil, from 2017 to 2020. Susceptibility profile was determined for ampicillin/sulbactam, amikacin, gentamicin, imipenem, meropenem, minocycline, polymyxin B and tigecycline. RESULTS: Overall, PMB was the most active agent against the set of A baumannii isolates over the period. Although stable, a high resistance rate was observed. CONCLUSIONS: Our results shown the presence of an extensively-drug resistant A baumannii complex isolates over the past four years. Polymyxin B has been the only antimicrobial agent that remain with a good in vitro activity. Strict surveillance and infection control measures are mandatory.

Impact of the Implementation of a Vancomycin Protocol on Trough Serum Vancomycin Concentrations in a Pediatric Intensive Care Unit.

BACKGROUND: Vancomycin is an antibiotic that is widely used in pediatric intensive care, but the safe and effective use of this drug is challenging. OBJECTIVE: This study aimed to assess the impact of a vancomycin protocol on trough serum concentrations. METHODS: We conducted a retrospective quasiexperimental study in patients aged ≤ 18 years in intensive care who received vancomycin for at least 5 days. Patients were divided into two groups: before and after a protocol implemented in 2017 that suggested an initial vancomycin dose of 60 mg/kg/day, target serum levels of 15-20 µg/mL, and dose adjustments. We compared patient characteristics, target serum level achievement, and vancomycin levels over time. RESULTS: Each group contained 65 patients; most were male infants with heart disease as the main reason for hospitalization. Only 29.2% of the patients had pretreatment cultures for bacteria identification recorded, with 1.5% identified as methicillin-resistant Staphylococcus aureus. For the first serum levels, 10.8% of patients in the pre-protocol group and 21.5% in the post-protocol group achieved the 15-20 µg/mL target (p = 0.153); during the first 5 days of treatment, this proportion significantly increased from 52.3 to 73.8% (p = 0.018). We observed a difference between the first and fifth levels: 8.9 µg/mL (95% confidence interval [CI] - 3.1 to 21) pre-protocol and 0.4 µg/mL (95% CI - 6.1 to 6.9) post-protocol (p = 0.175). CONCLUSIONS: Reaching adequate trough vancomycin concentrations in critically ill pediatric patients remains a challenge, and clinical practice protocols allow better dose adjustment and control even when monitoring technologies are unavailable.

Polymyxin NP tests (from colonies and directly from blood cultures): accurate and rapid methodologies to detect polymyxin B susceptibility among Enterobacterales.

Detection of polymyxins susceptibility is challenging. We aimed to evaluate Rapid Polymyxin NP from colonies (NP-colony) and directly from positive blood bottles (NP-bottle), using polymyxin B instead of colistin among Enterobacterales. Both had similar and acceptable accuracy. This is the first study performing NP-bottle using polymyxin B instead of colistin.

Impact of the blue-carba rapid test for carbapenemase detection on turnaround time for an early therapy against Pseudomonas aeruginosa.

BACKGROUND: To determine the turnaround time from a blue-carba result until a final microbiological report (bacterial identification plus antimicrobial susceptibility profile) and to infer the impact of an early therapeutic intervention based on the blue-carba results. METHODS: Pseudomonas aeruginosa isolates were recovered from hospitalized patients from Porto Alegre, Brazil, and tested by blue-carba test. Time required for a blue-carba result, right after the sample processing, was compared with those required to get final report (specie identification and antimicrobial susceptibility profile) Isolates blue-carba positive were tested by phenotypically and genotypically for Klebsiella pneumoniae carbapenemase and metallo-ß-lactamase genes. RESULTS: A total of 199 isolates were analyzed and 23 (11.6%) were blue-carba positive and harboring the blaSPM-1-like gene. Fifty-two (26.1%) isolates were blue-carba negative but resistant to meropenem and/or imipenem. Polymyxin B and ceftolozane/tazobactam (this latter except for SPM-1 producers) were 100% active for all P. aeruginosa isolates, a blue-carba test allow an earlier intervention or adequacy of therapy. CONCLUSIONS: Early adequacy can be promoted by blue-carba test for 11.6% of SPM-1-producing P. aeruginosa isolates, polymyxin B could be prior associated and ceftolozane/tazobactam withdrawn from therapy. For the remaining isolates, empirical therapy involving ceftolozane/tazobactam can be maintained with greater likelihood of adequacy. An active communication between laboratory and clinical services is necessary to better explore these earlier blue-carba results, significantly reducing the time for a first intervention.

Evaluation of a polymyxin drop test for polymyxin resistance detection among non-fermentative gram-negative rods and enterobacterales resistant to carbapenems.

To assess the performance of the drop test for polymyxin B resistance detection among Enterobacterales and non-fermentative gram-negative rods resistant to carbapenems. Seven hundred and fifteen carbapenem-resistant isolates were tested: 628 Enterobacterales species and 87 non-fermentative gram-negative rods. For the polymyxin drop test, concentrations range from 0.25 to 8.0 µg/mL. Broth microdilution, as gold standard, was performed using in-house-prepared panels and interpreted according to the CLSI guidelines. Results were interpreted in terms of categorical agreements and discrepancies. Accuracy for a drop of polymyxin B at 2.0, 4.0 and 8.0 was calculated as better cutoff for resistance determination. No very major error was observed among all isolates, and 95.5% of agreement was observed among Enterobacterales, particularly for Klebsiella pneumoniae. A higher accuracy (95.1%) was obtained when a single drop of polymyxin B at 4.0 µg/mL was applied. Polymyxin drop test presented >95% of categorical agreement, without very major errors, for KPC-producing K. pneumoniae isolates. An accuracy of 95.1% was obtained with a single drop at 4.0 µg/mL polymyxin B. Polymyxin B drop is an easy and feasible test and may allow a reduction on the turnaround time for polymyxin resistance detection and impacting on early implementation of accurate therapeutic interventions.

Resistance profile to antimicrobials agents in methicillin-resistant Staphylococcus aureus isolated from hospitals in South Brazil between 2014-2019.

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen causing healthcare-associated infections. Owing to the restricted use of beta-lactams in MRSA infections, non-beta-lactam antimicrobials are required for treatment. However, MRSA can develop resistance mechanisms to non-beta-lactam antimicrobials, which reduces viable treatment options. Here, we evaluated the antimicrobial susceptibility and resistance genes of MRSA isolated from hospitalized patients in South Brazil. METHODS: The antimicrobial susceptibilities of hospital MRSA (217) isolates were determined by disk diffusion or microdilution methods. Additionally, the presence of 14 resistance genes and SCCmec typing was performed by PCR. RESULTS: Among the antimicrobials tested, we observed high erythromycin (74.2%), ciprofloxacin (64.5%), and clindamycin (46.1%) resistance rates and complete susceptibility to linezolid and vancomycin. Seventeen different patterns of MRSA antimicrobial resistance were observed, of which 42.9% represented multidrug resistance. Among erythromycin-resistant MRSA, 53.4%, 45.3%, 37.9%, 13.0%, and 6.8% carried ermA, msrA, msrB, ermC, and ermB genes, respectively. Among clindamycin-resistant MRSA, 83%, 17%, 10%, 4%, and 2% carried ermA, ermC, ermB, linA, and linB genes, respectively. Among gentamicin-resistant MRSA, 96.8%, 83.9%, and 9.7% carried aac(6')/aph(2''), aph(3')-IIIa, and ant(4')-Ia genes, respectively. Among tetracycline-resistant MRSA, 6.5% and 93.5% carried tetK and tetM genes, respectively. Lastly, among trimethoprim/sulfamethoxazole-resistant MRSA, 13.3% and 100% carried dfrA and dfrG genes, respectively. The SCCmec type IV isolates were detected more frequently, whereas the SCCmec type III isolates exhibited higher multidrug resistance. CONCLUSIONS: The study data provides information regarding the MRSA resistance profile in South Brazil that is associated with the clinical conditions of patients and can contribute to clinical decision-making.

Vancomycin MIC and agr dysfunction in invasive MRSA infections in southern Brazil.

In methicillin-resistant Staphylococcus aureus (MRSA) treatment, the vancomycin minimum inhibitory concentration (MIC) increase, vancomycin heteroresistance (hVISA) presence, and accessory gene regulator (agr) dysfunction are predictors of vancomycin therapy failure. This study evaluated the association between vancomycin MIC (≥ 1.0 µg/mL) and agr dysfunction in invasive MRSA isolates. Vancomycin MIC, hVISA phenotype, agr group, and function were determined in 171 MRSA isolates obtained between 2014 and 2019 from hospitals in Porto Alegre, Brazil. All MRSA were susceptible to vancomycin; 16.4% of these had MIC ≥ 1.0 µg/mL. Seventeen MRSA isolates expressed the hVISA phenotype; 35.3% of them had MIC of 1.5 µg/mL. agr groups I (40.9%) and II (47.1%) were the most found groups for MRSA and hVISA isolates, respectively. The proportion of MRSA with vancomycin MIC ≥ 1.0 µg/mL in agr group II was significantly higher than in agr groups I and III (p = 0.002). agr dysfunction was observed in 4.7% (8/171) of MRSA, especially those with vancomycin MIC ≥ 1.0 µg/mL (p < 0.001). In addition, six isolates (35.3%; 6/17) with hVISA phenotype presented agr dysfunction, which was significantly higher than that in non-hVISA phenotype (p < 0.001). In conclusion, agr dysfunction in MRSA is associated with vancomycin MIC ≥ 1.0 µg/mL and hVISA phenotype, which suggests that agr dysfunction might confer potential advantages on MRSA to survive in invasive infections.