Unusual and Unconsidered Mechanisms of Bacterial Resilience and Resistance to Quinolones.

Quinolone resistance has been largely related to the presence of specific point mutations in chromosomal targets, with an accessory role of impaired uptake and enhanced pump-out. Meanwhile the relevance of transferable mechanisms of resistance able to protect the target of pump-out or inactivate quinolones has been increasingly reported since 1998. Nevertheless, bacteria have other strategies and mechanisms allowing them to survive and even proliferate in the presence of quinolones, which might be qualified as resistance or resilience mechanisms. These include decreasing levels of quinolone target production, transient amoeba protection, benthonic lifestyle, nutrient-independent slow growth, activation of stringent response, inactivation or degradation of quinolones as well as apparently unrelated or forgotten chromosomal mutations. These mechanisms have been largely overlooked, either because of the use of classical approaches to antibiotic resistance determination or due to the low increase in final minimum inhibitory concentration levels. This article is devoted to a review of a series of these mechanisms.

Failure in syndromic management due to drug-resistant Mycoplasma genitalium in Florianópolis, South Brazil / Falha no manejo sindrômico devido a Mycoplasma genitalium resistente em Florianópolis, Sul do Brasil

Introduction: Mycoplasma genitalium is a bacterium associated with sexually transmitted infections that can cause urethritis in men and complications in women, including preterm birth. Increasing macrolide resistance in M. genitalium poses challenges to treatment efficacy. Objective: To present a case of treatment failure of urethritis caused by macrolide-resistant M. genitalium. Case report: This case report describes a 20-year-old man with persistent urethral symptoms despite azithromycin treatment, wherein M. genitalium harbored the A2058G mutation in the 23S rRNA. Subsequent treatment with moxifloxacin resolved symptoms and cleared M. genitalium. Conclusion: The study highlights the importance of resistance testing to guide antimicrobial therapy and emphasizes the need for updated treatment guidelines in Brazil. (AU)

Introdução:Mycoplasma genitalium é uma bactéria associada a infecções sexualmente transmissíveis, que pode causar uretrite em homens e complicações em mulheres, incluindo nascimento prematuro. O aumento da resistência aos macrolídeos em M. genitalium coloca desafios à eficácia do tratamento. Objetivo: Apresentar um caso de falha terapêutica de uretrite causada por M. genitalium resistente aos macrolídeos. Relato de caso: Este relato de caso descreve um homem de 20 anos com sintomas uretrais persistentes, apesar do tratamento com azitromicina, em que M. genitalium possuía a mutação A2058G no rRNA 23S. O tratamento subsequente com moxifloxacino resolveu os sintomas e eliminou M. genitalium. Conclusão: O estudo destacou a importância dos testes de resistência para orientar a terapia antimicrobiana e enfatizou a necessidade de atualizar as diretrizes de tratamento no Brasil. (AU)

Norfloxacin prophylaxis effect on multidrug resistance in patients with cirrhosis and bacterial infections.

It is unclear whether norfloxacin predisposes to infections by multidrug-resistant organisms (MDROs). We aimed to evaluate if patients with cirrhosis receiving norfloxacin prophylaxis at the time of the diagnosis of bacterial infections were more likely to present a multidrug-resistant isolate than those without prophylaxis. This is a cross-sectional study of hospitalized patients with cirrhosis and bacterial infections from Argentina and Uruguay (NCT03919032) from September 2018 to December 2020. The outcome variable was a multidrug-resistant bacterial infection. We used inverse probability of treatment weighting to estimate the odds ratio (OR) of norfloxacin on infection caused by MDROs considering potential confounders. Among the 472 patients from 28 centers, 53 (11%) were receiving norfloxacin at the time of the bacterial infection. Patients receiving norfloxacin had higher MELD-sodium, were more likely to have ascites or encephalopathy, to receive rifaximin, beta-blockers, and proton-pump inhibitors, to have a nosocomial or health-care-associated infection, prior bacterial infections, admissions to critical care units or invasive procedures, and to be admitted in a liver transplant center. In addition, we found that 13 (24.5%) patients with norfloxacin and 90 (21.5%) of those not receiving it presented infections caused by MDROs (adjusted OR 1.55; 95% CI: 0.60-4.03; p = 0.360). The use of norfloxacin prophylaxis at the time of the diagnosis of bacterial infections was not associated with multidrug resistance. These results help empiric antibiotic selection and reassure the current indication of norfloxacin prophylaxis in well-selected patients.Study registration number: NCT03919032.

Tuberculosis treatment without rifampin in kidney/kidney-pancreas transplantation: A case series report.

BACKGROUND: The best approach to tuberculosis (TB) treatment in transplanted patients is still unknown. Current guidelines are based on evidence either extrapolated from other populations or observational. Rifampin-containing regimens have strong pharmacokinetic interactions with immunosuppressive regimens, with high rates of organ dysfunction and ∼20% mortality. This report describes the results obtained using non-rifampin-containing regimens to treat confirmed TB in adult patients with kidney/kidney-pancreas transplantation. METHODS: Retrospective data analysis from confirmed TB cases in adult kidney/kidney-pancreas transplant recipients (2006-2019), treated "de novo" with non-rifampin-containing regimens. RESULTS: Fifty-seven patients had confirmed TB. Thirty patients were treated "de novo" with non-rifampin-containing regimens. These patients' mean age was 49.24 (±11.50) years. Induction immunosuppression was used in 22 patients. Maintenance immunosuppression was tacrolimus-mycophenolate-steroids in 13 (43%), sirolimus-mycophenolate-steroids in 6 (20%), and other immunosuppressive regimens in 11 (36%). Belatacept was used in four patients. TB localizations: pulmonary 43%; disseminated 23%; extrapulmonary 33%. Twenty-seven (90%) patients completed treatment with isoniazid, ethambutol, and levofloxacin (12 months, 23; 9 months, 3; 6 months, 1); 12 of these patients also received pyrazinamide for the first 2 months and were cured with functioning grafts. One patient (3%) lost the graft while on treatment. Two patients (7%) died while on TB treatment. Median (range) follow-up after completion of TB treatment was 32 (8-150) months. No TB relapses were observed. CONCLUSIONS: Results with non-rifampin-containing TB treatments in this case series were better (in terms of mortality and graft dysfunction) than those previously described with rifampin-containing regimens in transplanted patients.

Aquatic Environments as Hotspots of Transferable Low-Level Quinolone Resistance and Their Potential Contribution to High-Level Quinolone Resistance.

The disposal of antibiotics in the aquatic environment favors the selection of bacteria exhibiting antibiotic resistance mechanisms. Quinolones are bactericidal antimicrobials extensively used in both human and animal medicine. Some of the quinolone-resistance mechanisms are encoded by different bacterial genes, whereas others are the result of mutations in the enzymes on which those antibiotics act. The worldwide occurrence of quinolone resistance genes in aquatic environments has been widely reported, particularly in areas impacted by urban discharges. The most commonly reported quinolone resistance gene, qnr, encodes for the Qnr proteins that protect DNA gyrase and topoisomerase IV from quinolone activity. It is important to note that low-level resistance usually constitutes the first step in the development of high-level resistance, because bacteria carrying these genes have an adaptive advantage compared to the highly susceptible bacterial population in environments with low concentrations of this antimicrobial group. In addition, these genes can act additively with chromosomal mutations in the sequences of the target proteins of quinolones leading to high-level quinolone resistance. The occurrence of qnr genes in aquatic environments is most probably caused by the release of bacteria carrying these genes through anthropogenic pollution and maintained by the selective activity of antimicrobial residues discharged into these environments. This increase in the levels of quinolone resistance has consequences both in clinical settings and the wider aquatic environment, where there is an increased exposure risk to the general population, representing a significant threat to the efficacy of quinolone-based human and animal therapies. In this review the potential role of aquatic environments as reservoirs of the qnr genes, their activity in reducing the susceptibility to various quinolones, and the possible ways these genes contribute to the acquisition and spread of high-level resistance to quinolones will be discussed.

Identificación de enterobacterias multirresistentes a antibióticos en muestras de heces de lactantes residentes en Talara, Piura, Perú / Identification of multidrug-resistant enterobacteriaceae in fecal samples from infants residing in Talara, Piura, Peru Arturo

La colonización fecal en lactantes por bacterias resistentes a los antimicrobianos es un potencial riesgo para futuras terapias antibióticas. Nuestro objetivo fue determinar la frecuencia y características sociodemográficas de lactantes portadores fecales de enterobacterias resistentes a ciprofloxacina (PFRC) y sus genes de resistencia asociados. Analizamos muestras fecales de 41 niños lactantes residentes en el distrito de Talara-Piura, Perú, en 2019. Evaluamos la presencia de 3 genes de resistencia a quinolonas: aac(6')-Ib-cr, qnrB y oqxA y 2 de betalactamasas: bla CTX-M, bla PER-2.El 68% de lactantes fueron PFRC, Escherichia coli (83,3%) fue el más frecuente. El análisis genotípico detectó: oqxA (41,1%), qnrB (26,7%) y aac(6')-Ib-cr (20%) y al gen bla CTX-M en el 93,3% de los aislados con betalactamasas. La elevada frecuencia de PFRC nos alertan sobre el potencial riesgo en la pérdida de utilidad de esta familia antibiótica en el área de estudio.

Fecal colonization by antimicrobial-resistant bacteria in infants is a potential risk for future antibiotic therapy. We aimed to determine the sociodemographic characteristics and frequency of infants who were fecal carriers of ciprofloxacin-resistant enterobacteriaceae (FCCRE) and their associated resistance genes. We analyzed fecal samples from 41 infants from the district of Talara, Piura, Peru in 2019. The presence of 3 quinolone resistance genes was evaluated: aac(6')-Ib-cr, qnrB and oqxA as well as of 2 beta-lactamase genes: bla CTX-M,bla PER-2. We found that 68% of infants were FCCRE, Escherichia coli (83.3%) was the most frequent bacteria. The genotypic analysis detected: oqxA (41.1%), qnrB (26.7%), aac(6')-Ib-cr (20%) and the bla CTX-M gene (93.3%) of the isolates with beta-lactamases. The high frequency of FCCRE alerts us of the potential risk of this antibiotic family becoming less useful over time.

Biological Effects of Quinolones: A Family of Broad-Spectrum Antimicrobial Agents.

Broad antibacterial spectrum, high oral bioavailability and excellent tissue penetration combined with safety and few, yet rare, unwanted effects, have made the quinolones class of antimicrobials one of the most used in inpatients and outpatients. Initially discovered during the search for improved chloroquine-derivative molecules with increased anti-malarial activity, today the quinolones, intended as antimicrobials, comprehend four generations that progressively have been extending antimicrobial spectrum and clinical use. The quinolone class of antimicrobials exerts its antimicrobial actions through inhibiting DNA gyrase and Topoisomerase IV that in turn inhibits synthesis of DNA and RNA. Good distribution through different tissues and organs to treat Gram-positive and Gram-negative bacteria have made quinolones a good choice to treat disease in both humans and animals. The extensive use of quinolones, in both human health and in the veterinary field, has induced a rise of resistance and menace with leaving the quinolones family ineffective to treat infections. This review revises the evolution of quinolones structures, biological activity, and the clinical importance of this evolving family. Next, updated information regarding the mechanism of antimicrobial activity is revised. The veterinary use of quinolones in animal productions is also considered for its environmental role in spreading resistance. Finally, considerations for the use of quinolones in human and veterinary medicine are discussed.

Characterization of a Novel Variant of the Quinolone-Resistance Gene qnrB (qnrB89) Carried by a Multi-Drug Resistant Citrobacter gillenii Strain Isolated from Farmed Salmon in Chile.

The main objective of this study was to characterize using whole-genome sequencing analysis, a new variant of the qnrB gene (qnrB89) carried by a fluoroquinolone-susceptible bacterium isolated from mucus of farmed Salmo salar fingerling in Chile. Citrobacter gillenii FP75 was identified by using biochemical tests and 16S ribosomal gene analysis. Nucleotide and amino acid sequences of the qnrB89 gene exhibited an identity to qnrB of 81.24% and 91.59%, respectively. The genetic environment of qnrB89 was characterized by the upstream location of a sequence encoding for a protein containing a heavy metal-binding domain and a gene encoding for a N-acetylmuramoyl-L-alanine amidase protein, whereas downstream to qnrB89 gene were detected the csp and cspG genes, encoding cold-shock proteins. The qnrB89 gene was located on a large chromosomal contig of the FP75 genome and was not associated with the 10-kb plasmid and class 1 integron harbored by the FP75 strain. This study reports for the first time the carriage of a qnrB gene by the C. gillenii species, and its detection in a bacterial strain isolated from farmed salmon in Chile.

Synthesis of endo-fused 5-unsubstituted Hexahydro-2H-pyrano[3,2-c]quinolinesvia Sequential Sc(OTf)3-catalyzed Cationic Imino-Diels-Alder Reaction/N-debenzylation using N-benzylanilines, 3,4-dihydro-2H-pyran and Paraformaldehyde under MW Irradiation.

BACKGROUND: Hexahydro-2H-pyrano[3,2-c]quinolines are known to have antibacterial, antifungal, and antitumor properties. Great efforts have been made to develop new synthetic methods that lead to the synthesis of valuable libraries. Extensive methodologies, low yields, excessive amounts of catalyst and expensive reactants are some of the limitations of current methodologies. AIMS AND OBJECTIVE: Developing a useful and efficient method to construct diversely substituted hexahydro-2Hpyrano[ 3,2-c]quinolines into good to excellent yields through a cationic imino-Diels-Alder/N-debenzylation methodology. METHOD: The cationic imino-Diels-Alder/N-debenzylation methodology was used for the preparation of substituted hexahydro-2H-pyrano[3,2-c]quinolines. It involves the use of Sc(OTf)3 for activation of cationic imino- Diels-Alder cycloaddition reaction of N-benzylanilines, 3,4-dihydro-2H-pyran and paraformaldehyde in MeCN; and microwave irradiation to shorten reaction time to afford new 6-benzyl-hexahydro-2H-pyrano[3,2- c]quinolines whose catalytic transfer debenzylation reactions with HCO2NH4 in the presence of Pd/C (10%) and methanol give the new 5-unsubstituted pyrano[3,2-c]quinolines in excellent yields. RESULTS: We found that optimal conditions for the preparation of hexahydro-2H-pyrano[3,2-c]quinolines were Sc(OTf)3 0.5 % and acetonitrile at 160°C for 15 min; and using paraformaldehyde obtained the 6-benzylhexahydro- 2H-pyrano [3,2-c]quinolines with excellent yields, while the N-debenzylation process using ammonium formate in the presence of Pd/C and methanol resulted in the synthesis of hexahydro-2H-pyrano [3,2-c] quinolines with quantitative yields (95-98%). CONCLUSION: We describe an efficient method to synthesize hexahydro-2H-pyrano[3,2-c]quinolines via the cationic imino-Diels-Alder/N-debenzylation methodology using Sc(OTf)3 0.5 % as Lewis Acid catalyst. Excellent yields of the products, use of MW irradiation, short times of reactions, and an efficient and highly diversified method are some of the main advantages of this new protocol.

Efficacy and safety of quinolones for the treatment of uncomplicated urinary tract infections in women: a network meta-analysis.

INTRODUCTION AND HYPOTHESIS: Uncomplicated urinary tract infection (uUTI) is defined as the presence of pathogenic organisms in the urinary tract without anatomical and functional abnormalities, is accompanied by inflammatory leukocytes and cytokines and may or may not develop clinical symptoms. The frequency of uncomplicated urinary tract infection is higher in young women. Several quinolone treatment regimens are available; however, since we do not know which is the best antibiotic regimen for the treatment of this urinary infection, we analyzed the published evidence and conducted a systematic review with network meta-analysis. The aim was to compare and hierarchize quinolones according to their efficacy and safety and to identify the best treatment for uncomplicated urinary tract infection in women through a systematic review with network meta-analysis. METHODS: Medline, Embase, LILACS, Cochrane CENTRAL and other databases were searched for trials. Bias in the trials was assessed using the Cochrane Collaboration tool. To analyze efficacy and adverse events, for direct comparisons, we obtained risk ratios and 95% confidence intervals by applying a fixed-effects model using tau2 and Q2 tests to calculate the heterogeneity. For the network meta-analysis, we analyzed the indirect comparisons by Bucher's method. RESULTS: We included 18 trials (8765 women). For premenopausal women, ofloxacin had a 57% probability of achieving remission but an 83% frequency of adverse events. For postmenopausal women, ofloxacin was 82% more effective for remission, with a 49% frequency of adverse events, compared with other types of quinolones. CONCLUSIONS: Compared with other quinolones, ofloxacin 200 mg once daily for a treatment duration < 3 days provides the highest clinical and bacteriological remission rates with the lowest relapse and resistance rates for the treatment of women with uUTIs. However, additional trials are needed to confirm our findings, especially when the treatment duration exceeds 3 days.

Uso de Quinolonas como Factor de Riesgo para Infección Oportunista Severa por Cándida en Pacientes Adultos Críticamente Enfermos

Resumen Introducción: Candida es uno de los microorganismos mayormente aislado de los hemocultivos positivos, mostrando un aumento de su prevalencia a nivel mundial debido a múltiples factores de riesgo siendo unos de los más importantes el uso de antibioticoterapia de espectro ampliado, como las quinolonas usados en pacientes críticos hospitalizados en salas de cuidado intensivo, de los cuales la literatura es tangencial en su relación con el desarrollo de candidiasis invasiva. Materiales y metodos: se realizó una búsqueda exhaustiva en las bases de datos biomédicas MEDLINE, PubMed, ScienceDirect, Scopus, Embase, utilizando la estrategia de búsqueda: "Candidemia AND Quinolones AND Adult" sin embargo también se usaron otras estrategias para aumentar la sensibilidad como: "Invasive candidiasis AND Quinolones" y "Candidemia OR Invasive candidiasis AND risk factors" incluyendo los idiomas inglés, español, francés y portugués, se tuvieron en cuenta artículos tipo: [Randomized Controlled Trial], [Clinical Trial], [Controlled Clinical Trial] y [Review] Resultados: la literatura biomédica es escasa en cuanto a la descripción de la relación entre el uso de quinolinas como factor de riesgo para desarrollar candidiasis invasiva, sin embargo se encontraron ocho estudios con significancia estadística importante que muestran una relación estrecha entre el fenómeno propuesto. Conclusiónes: Las quinolonas de uso sistémico como Ciprofloxacino, son un factor de riesgo confirmado asociado a infecciones invasivas por hongos tipo Candida.

Abstract Introduction: Candida is one of the microorganisms most frequently isolated from positive blood cultures, showing an increase in its prevalence worldwide due to multiple risk factors, one of the most important being the use of extended-spectrum antibiotic therapy, such as quinolones used in critical patients in intensive care wards, of which the literature is tangential in its relationship with the development of invasive candidiasis, Methods: a search of biomedical databases MEDLINE, PubMed, ScienceDirect, Scopus, Embase, was performed using the search strategy: "Candidemia AND Quinolones AND Adult" other strategies were also used to increase sensitivity such as: "Invasive candidiasis AND Quinolones" and "Candidemia OR Invasive candidiasis AND risk factors" including English, Spanish, French and Portuguese languages, articles type were taken into account: [Randomized Controlled Trial], [Clinical Trial], [Controlled Clinical Trial] and [Review]. Results: The biomedical literature is scarce regarding the description of the relationship between the use of quinolones as a risk factor for developing invasive candidiasis; however, eight studies were found with important statistical significance that show a close relationship between the proposed phenomenon. Conclusion: Systemic quinolones such as Ciprofloxacin are a confirmed risk factor associated with invasive fungal infections such as Candida.

Multidrug-Resistant CTX-M and CMY-2 Producing Escherichia coli Isolated from Healthy Household Dogs from the Great Metropolitan Area, Costa Rica.

Objective: This study aimed to determine the prevalence of fecal carriage of antibiotic-resistant Escherichia coli of healthy household dogs with an emphasis on extended-spectrum ß-lactamases (ESBL), AmpC-type ß-lactamases and resistance to quinolones. Materials and Methods: Rectal swabs were collected from 74 dogs without any clinical evidence of gastrointestinal disease. Samples were cultured on MacConkey agar plates and MacConkey supplemented with 2 µg/mL cefotaxime or 5 µg/mL ciprofloxacin. Isolates were identified with Vitek 2 Compact and susceptibility testing performed by Kirby Bauer disk diffusion method. Minimal inhibitory concentration (MIC) was done on isolates resistant to cefotaxime, ciprofloxacin, and nalidixic acid. PCR amplification was performed to detect CTX-M and CMY-2. Isolates positive for CTX-M and/or CMY-2 were selected for whole-genome sequencing. Results: Multiresistance was detected in 56% of the isolates. A high percentage of resistance was detected for cefazolin (63%), ampicillin (54%), streptomycin (49%), nalidixic acid (42%) and tetracycline (38%). The MIC50 and MIC90 for isolates resistant to cefotaxime (24%) was determined as 16 and >250 µg/mL, respectively; for ciprofloxacin (18%), 125 and 250 µg/mL, respectively. ESBL (CTX-M type) and AmpC (CMY-2 type) were detected in 6 (7.1%) and 14 (19%) of the isolates, respectively. Whole-genome sequence analysis showed high genetic diversity in most of the isolates and a large variety of resistance mechanisms, including mobile genetic elements. Conclusion: The frequency of multidrug-resistant E. coli is worrying, mainly because of the presence of many isolates producing ESBL and AmpC ß-lactamases. Based on the "One Health" concept, considering the relationships between animals, humans, and the environment, these data support the notion that companion animals are important reservoirs of multidrug-resistant bacteria.

Domestic wastewater treatment plants as sources of macrolide-lincosamide-streptogramin B- and penicillin-resistant Staphylococcus aureus in Brazil / Plantas de tratamiento de aguas residuales domésticas como fuentes de Staphylococcus aureus resistente a macrólidos-lincosamida-estreptogramina B- y penicilina en Brasil / Estações de tratamento de águas residuais domésticas como fontes de Staphylococcus aureus resistente a macrolídeo-lincosamida-estreptograma e B- e penicilina no Brasil

SUMMARY Staphylococcus aureus is one of the main bacteria that affect human health. Its reduced susceptibility to beta-lactam antibiotics has driven the clinical use of macrolides and lincosamides. However, the presence of macrolide-lincosamide-streptogramin B (MLSB)-resistant S. aureus strains is increasingly common. Wastewater treatment plants (WWTPs) are the main anthropogenic source of resistance determinants. However, few studies have assessed the importance of this environment on the dissemination of MLSB-resistant S. aureus strains. Thus, we aimed to evaluate the impact of a domestic WWTP on the resistance to MLSB and penicillin in S. aureus in southeast Brazil. Of the 35 isolates tested, 40.6% were resistant to penicillin. Resistance to erythromycin (8.6%) and quinolones (2.8%) was less common. Despite the low rate of resistance to clindamycin (2.8%), many isolates showed reduced susceptibility to this antibiotic (57.1%). Regarding the resistance phenotypes of staphylococci isolates, inducible MLSB resistance (D-test positive) was found in two isolates. In addition, 27 S. aureus isolates showed the ability to produce penicillinase. In this article, we report for the first time the importance of WWTPs in the dissemination of MSLB resistance among S. aureus from southeast Brazil.

RESUMEN Staphylococcus aureus es una de las principales bacterias que afectan la salud humana. Su susceptibilidad reducida a los antibióticos betalactámicos ha impulsado el uso clínico de macrólidos y lincosamidas. Sin embargo, la presencia de cepas resistentes a macrólido-lincosamida-estreptogramina B (MLSB) de S. aureus es cada vez más común. Las plantas de tratamiento de aguas residuales (PTAR) son la principal fuente antropogénica de determinantes de resistencia. Sin embargo, pocos estudios han evaluado la importancia de este entorno en la diseminación de cepas de S. aureus resistentes a MLSB. Nuestro objetivo fue evaluar el impacto de una PTAR doméstica en MLSB y la resistencia a la penicilina en S. aureus en el sureste de Brasil. De los 35 aislamientos analizados, el 40,6% eran resistentes a la penicilina. La resistencia a la eritromicina (8,6%) y quinolonas (2,8%) fue menos común. A pesar de la baja tasa de resistencia a la clindamicina (2,8%), muchos aislamientos mostraron sensibilidad reducida a este antibiótico (57,1%). Con respecto a los fenotipos de resistencia de los aislamientos de estafilococos, la resistencia inducible a MLSB (prueba D positiva) se encontró en dos aislamientos. Además, 27 aislamientos de S. aureus mostraron la capacidad de producir penicilinasa. En este artículo informamos, por primera vez, la importancia de las PTAR en la difusión de la resistencia a MSLB entre S. aureus del sureste de Brasil.

RESUMO O Staphylococcus aureus é uma das principais bactérias que afetam a saúde humana. Sua reduzida suscetibilidade aos antibióticos beta-lactâmicos tem impulsionado o uso clínico de macrolídeos e lincosamidas. No entanto, a presença de cepas de S. aureus resistentes a macrolídeo-lincosamida-estreptogramina B (MLSB) é cada vez mais comum. As estações de tratamento de esgoto (ETEs) são a principal fonte antropogênica de determinantes de resistência. No entanto, poucos estudos avaliaram a importância desse ambiente na disseminação de cepas de S. aureus resistentes ao MLSB. Assim, nosso objetivo foi avaliar o impacto de uma ETE doméstico na resistência ao MLSB e à penicilina em S. aureus no sudeste do Brasil. Dos 35 isolados testados, 40,6% eram resistentes à penicilina. Resistência à eritromicina (8,6%) e quinolonas (2,8%) foi menos comum. Apesar da baixa taxa de resistência à clindamicina (2,8%), muitos isolados apresentaram sensibilidade reduzida a esse antibiótico (57,1%). Em relação aos fenótipos de resistência dos isolados de estafilococos, a resistência induzível ao MLSB (D-teste positivo) foi encontrada em dois isolados. Além disso, 27 isolados de S. aureus mostraram a capacidade de produzir penicilinase. Neste artigo relatamos pela primeira vez a importância das ETEs na disseminação da resistência do MSLB entre S. aureus do sudeste do Brasil.

Quinolones resistance in Salmonella spp. isolated from broilers and chickens carcasses under federal inspection / Resistência à quinolonas em Salmonella spp. isoladas de frangos vivos e carcaças sob inspeção federal

We analyzed 77 Salmonella spp. strains, from which 20 were isolated from broilers (cloacal swabs) and 57 from chickens from slaughterhouses under federal inspection. The following serotypes were identified: Salmonella Saint Paul (29), Salmonella Heidelberg (27), Salmonella Anatum (9), Salmonella Cerro (5), Salmonella Senftenberg (5), Salmonella enterica (O: 4,5) (1) and Salmonella enterica (O: 9.12) (1). Fifteen strains (19.5%) were resistant to enrofloxacin, six (7.8%) to ciprofloxacin, and 26 (33.8%) to nalidixic acid in the Disk Diffusion Test. The fifteen enrofloxacin resistant strains were selected for the PCR to detect the genes gyrA, gyrB, parC, and parE, and genetic sequencing to identify mutations in these genes. Five strains (33.3%) had point mutations in the gyrA gene, and one (6.7%) presented a point mutation in the parC gene. None of the 15 strains had mutations in the gyrB and parE genes, and none had more than one mutation in the gyrA gene or the other genes. The presence of point mutations in the strains studied corroborates with the phenotypic resistance observed to nalidixic acid. However, it did not explain the resistance to fluoroquinolones found in the 15 strains. Other mechanisms may be related to the fluoroquinolones resistance, highlighting the need for additional mutation screening.(AU)

Foram analisadas neste estudo 77 estirpes de Salmonella spp., 20 isoladas de frangos vivos (suabes de cloaca) e 57 isoladas de carcaças, provenientes de abatedouros frigoríficos sob Inspeção Federal. Foram identificados os seguintes sorotipos: Salmonella Saint Paul (29), Salmonella Heidelberg (27), Salmonella Anatum (9), Salmonella Cerro (5), Salmonella Senftenberg (5), Salmonella enterica (O: 4,5) (1) e Salmonella enterica (O: 9,12) (1). Do total de estirpes estudadas, 15 (19,5%) se mostraram resistentes à enrofloxacina, seis (7,8%) à ciprofloxacina e 26 (33,8%) ao ácido nalidíxico no Teste de Difusão em Disco. Foram selecionadas as 15 estirpes resistentes à enrofloxacina para a realização da PCR para detecção dos genes gyrA, gyrB, parC e parEe para sequenciamento genético do produto da PCR para identificação de mutações nesses genes. Cinco estirpes (33,3%) apresentaram mutações pontuais no gene gyrA e uma (6,7%) apresentou mutação pontual no gene parC. Nenhuma das 15 estirpes apresentou mutações nos genes gyrB e parE e nenhuma apresentou mais de uma mutação no gene gyrA ou nos outros genes. A existência apenas de mutações pontuais em alguns genes das estirpes analisadas está de acordo com a resistência fenotípica observada ao ácido nalidíxico, mas não explica a resistência às fluoroquinolonas encontrada nas 15 estirpes. Outros mecanismos de resistência podem estar relacionados à resistência encontrada às fluoroquinolonas e estudos adicionais são necessários para investigar sua presença.(AU)

Corrigendum: Transduction as a Potential Dissemination Mechanism of a Clonal qnrB19-Carrying Plasmid Isolated From Salmonella of Multiple Serotypes and Isolation Sources.

[This corrects the article DOI: 10.3389/fmicb.2019.02503.].

Regioselective preparation and NMR spectroscopy study of 2-chloro-4-ethoxy-quinoline for the synthesis of 2-((3-aminopropyl)amino)quinolin-4(1H)-one.

Herein, we describe the C4-ethoxylation of 2,4-dichloroquinoline to prepare 2-chloro-4-ethoxy-quinoline (3), which is a prominent intermediate used for the synthesis of 2-substituted quinolones. To achieve this goal, we studied different conditions for the reaction between 2,4-dichloroquinoline and sodium ethoxide. We discovered that the use of 18-crown-6 ether as an additive and dimethylformamide as the reaction solvent allowed us to obtain the desired product 3 in very good yield and selectivity. In addition, a definitive distinction between the C2 and C4 ethoxylation products was achieved using 1 H─15 N heteronuclear multiple bond correlation. Compound 3 is an intermediate used for the synthesis of 2-((3-aminopropyl)amino)quinolin-4(1H)-one, which displays peculiar behavior during 1 H nuclear magnetic resonance analysis, such as the broadening of the H8 singlet and unexpected deuteration at the C8-position. Effort has been dedicated to understand these findings.

Quinolones resistance in Salmonella spp. isolated from broilers and chickens carcasses under federal inspection

ABSTRACT: We analyzed 77 Salmonella spp. strains, from which 20 were isolated from broilers (cloacal swabs) and 57 from chickens from slaughterhouses under federal inspection. The following serotypes were identified: Salmonella Saint Paul (29), Salmonella Heidelberg (27), Salmonella Anatum (9), Salmonella Cerro (5), Salmonella Senftenberg (5), Salmonella enterica (O: 4,5) (1) and Salmonella enterica (O: 9.12) (1). Fifteen strains (19.5%) were resistant to enrofloxacin, six (7.8%) to ciprofloxacin, and 26 (33.8%) to nalidixic acid in the Disk Diffusion Test. The fifteen enrofloxacin resistant strains were selected for the PCR to detect the genes gyrA, gyrB, parC, and parE, and genetic sequencing to identify mutations in these genes. Five strains (33.3%) had point mutations in the gyrA gene, and one (6.7%) presented a point mutation in the parC gene. None of the 15 strains had mutations in the gyrB and parE genes, and none had more than one mutation in the gyrA gene or the other genes. The presence of point mutations in the strains studied corroborates with the phenotypic resistance observed to nalidixic acid. However, it did not explain the resistance to fluoroquinolones found in the 15 strains. Other mechanisms may be related to the fluoroquinolones resistance, highlighting the need for additional mutation screening.

RESUMO: Foram analisadas neste estudo 77 estirpes de Salmonella spp., 20 isoladas de frangos vivos (suabes de cloaca) e 57 isoladas de carcaças, provenientes de abatedouros frigoríficos sob Inspeção Federal. Foram identificados os seguintes sorotipos: Salmonella Saint Paul (29), Salmonella Heidelberg (27), Salmonella Anatum (9), Salmonella Cerro (5), Salmonella Senftenberg (5), Salmonella enterica (O: 4,5) (1) e Salmonella enterica (O: 9,12) (1). Do total de estirpes estudadas, 15 (19,5%) se mostraram resistentes à enrofloxacina, seis (7,8%) à ciprofloxacina e 26 (33,8%) ao ácido nalidíxico no Teste de Difusão em Disco. Foram selecionadas as 15 estirpes resistentes à enrofloxacina para a realização da PCR para detecção dos genes gyrA, gyrB, parC e parEe para sequenciamento genético do produto da PCR para identificação de mutações nesses genes. Cinco estirpes (33,3%) apresentaram mutações pontuais no gene gyrA e uma (6,7%) apresentou mutação pontual no gene parC. Nenhuma das 15 estirpes apresentou mutações nos genes gyrB e parE e nenhuma apresentou mais de uma mutação no gene gyrA ou nos outros genes. A existência apenas de mutações pontuais em alguns genes das estirpes analisadas está de acordo com a resistência fenotípica observada ao ácido nalidíxico, mas não explica a resistência às fluoroquinolonas encontrada nas 15 estirpes. Outros mecanismos de resistência podem estar relacionados à resistência encontrada às fluoroquinolonas e estudos adicionais são necessários para investigar sua presença.

Transduction as a Potential Dissemination Mechanism of a Clonal qnrB19-Carrying Plasmid Isolated From Salmonella of Multiple Serotypes and Isolation Sources.

Antimicrobial resistance is an increasing problem worldwide, and Salmonella spp. resistance to quinolone was classified by WHO in the high priority list. Recent studies in Europe and in the US reported the presence of small plasmids carrying quinolone resistance in Enterobacteriaceae isolated from poultry and poultry products. The aims of this study were to identify and characterize plasmid-mediated quinolone resistance in Salmonella spp. and to investigate transduction as a possible mechanism associated to its dissemination. First, we assessed resistance to nalidixic acid and/or ciprofloxacin in 64 Salmonella spp. and detected resistance in eight of them. Genomic analyses determined that six isolates of different serotypes and sources carried an identical 2.7-kb plasmid containing the gene qnrB19 which confers quinolone resistance. The plasmid detected also has high identity with plasmids reported in the US, Europe, and South America. The presence of similar plasmids was later surveyed by PCR in a local Salmonella collection (n = 113) obtained from diverse sources: food (eggs), wild and domestic animals (pigs, horse, chicken), and human clinical cases. qnrB19-carrying plasmids were found in 8/113 Salmonella tested strains. A bioinformatics analysis including Chilean and previously described plasmids revealed over 95.0% of nucleotide identity among all the sequences obtained in this study. Furthermore, we found that a qnrB19-carrying plasmid can be transferred between Salmonella of different serotypes through a P22-mediated transduction. Altogether our results demonstrate that plasmid-mediated quinolone resistance (PMQR) is widespread in Salmonella enterica of different serotypes isolated from human clinical samples, wild and domestic animals, and food in Chile and suggest that transduction could be a plausible mechanism for its dissemination. The occurrence of these antimicrobial resistance elements in Salmonella in a widespread area is of public health and food safety concern, and it indicates the need for increased surveillance for the presence of these plasmids in Salmonella strains and to assess their actual impact in the rise and spread of quinolone resistance.

Transferable Mechanisms of Quinolone Resistance from 1998 Onward.

While the description of resistance to quinolones is almost as old as these antimicrobial agents themselves, transferable mechanisms of quinolone resistance (TMQR) remained absent from the scenario for more than 36 years, appearing first as sporadic events and afterward as epidemics. In 1998, the first TMQR was soundly described, that is, QnrA. The presence of QnrA was almost anecdotal for years, but in the middle of the first decade of the 21st century, there was an explosion of TMQR descriptions, which definitively changed the epidemiology of quinolone resistance. Currently, 3 different clinically relevant mechanisms of quinolone resistance are encoded within mobile elements: (i) target protection, which is mediated by 7 different families of Qnr (QnrA, QnrB, QnrC, QnrD, QnrE, QnrS, and QnrVC), which overall account for more than 100 recognized alleles; (ii) antibiotic efflux, which is mediated by 2 main transferable efflux pumps (QepA and OqxAB), which together account for more than 30 alleles, and a series of other efflux pumps (e.g., QacBIII), which at present have been sporadically described; and (iii) antibiotic modification, which is mediated by the enzymes AAC(6')Ib-cr, from which different alleles have been claimed, as well as CrpP, a newly described phosphorylase.

Cambios en las prescripciones y el consumo de antimicrobianos, luego de la implementación de recomendaciones de uso: experiencia en un hospital universitario / Changes in prescriptions and antibiotic consumption after the implementation of recommendations for use: experience in a university hospital

Resumen Introduccion: Actualmente cerca de la mitad de las prescripciones de antimicrobianos son inadecuadas, lo que aumenta la resistencia bacteriana. Tanto cefalosporinas como fluoroquinolonas se asocian con este fenomeno: aumento de bacterias productoras de β-lactamasas e infecciones por Clostridioides difficile, por lo que las agencias reguladoras buscan racionalizar su uso. Objetivo: Evaluar el efecto de recomendaciones para el uso adecuado de antimicrobianos en la proporcion de prescripciones inadecuadas de ceftriaxona y fluoroquinolonas. Metodologia: Se desarrollo un estudio de antes y despues, prospectivo e intervencional, que comparo la calidad y la cantidad de uso de ceftriaxona y fluoroquinolonas antes y despues de la implementacion de recomendaciones de uso para tratamientos de enfermedades infecciosas adquiridas en la comunidad. Los parametros medidos fueron: proporcion de prescripciones inadecuadas y DDD. Los datos se analizaron por medio del test de χ2, correccion de Fisher y test de Student. Resultados: Se evaluaron 206 pacientes, observandose una disminucion de 35% en las prescripciones inadecuadas, una reduccion del consumo de ceftriaxona y levofloxacina y un aumento significativo de la utilizacion de ampicilina/sulbactam. Conclusiones: La implementacion de recomendaciones de uso basadas en evidencia cientifica y susceptibilidad local, permitieron disminuir la proporcion de prescripciones inadecuadas y reducir el consumo de ceftriaxona y fluoroquinolonas.

Background: Nowadays about half of antibiotic prescriptions are inadequate, increasing bacterial resistance. Both cephalosporins and fluoroquinolones are associated with this phenomenon: increase of β-lactamase producing bacteria and Clostridioides difficile infections, which is why regulatory agencies seek to rationalize their use. Aim: To evaluate the effect of use recommendations on the proportion of inadequate prescriptions of ceftriaxone and fluoroquinolones. Methods: A prospective and interventional study was developed, comparing the quality and quantity of use of ceftriaxone and fluoroquinolones before and after the implementation of use recommendations for treatments of infectious diseases acquired at the community. The outcomes were: proportion of inadequate prescriptions and defined daily dose (DDD). Data were analyzed using the Chi-square test, Fisher's correction and Student's test. Results: A total of 206 patients were evaluated, a 35% decrease in inadequate prescriptions, a decline in the consumption of ceftriaxone and levofloxacin, and a significant increase in the use of ampicillin/ sulbactam was observed. Conclusions: The implementation of use recommendations based on scientific evidence and local susceptibility allowed to reduce the proportion of inadequate prescriptions and to reduce de consumption of ceftriaxone and fluoroquinolones.