In the near future, the overlap of Coronavirus disease 2019 (COVID-19) and dengue epidemics is a concrete threat in tropical regions. Co-epidemics of COVID-19 and dengue could be an overwhelming challenge for health systems in low- and middle-income countries. In this work, we investigated potential serological cross-reactions between COVID-19 and dengue patients. Among 32 COVID-19 positive sera, no positive Dengue virus (DENV) IgG/IgM results were observed. On the other hand, one false-positive result was observed among 44 DENV-positive sera tested for COVID-19 antibodies with each of the two rapid tests used. Further data on accuracy of COVID-19 diagnostic test are urgently warranted.

High quinolone resistance rates were observed among oxyiminocephalosporin-resistant enterobacteria. In the present study, we searched for the prevalence of plasmid-mediated quinolone resistance (PMQR) genes within the 55 oxyiminocephalosporin-resistant enterobacteria collected in a previous survey. The main PMQR determinants were aac(6')-Ib-cr and qnrB, which had prevalence rates of 42.4% and 33.3%, respectively. The aac(6')-Ib-crgene was more frequently found in CTX-M-15-producing isolates, while qnrB was homogeneously distributed among all CTX-M producers.

OBJECTIVE: To identify the outer membrane protein absent in the resistant isolates and to determine both the causes of its absence in the membrane and the presence of other mechanisms of carbapenem resistance in clinical isolates of Pseudomonas aeruginosa. METHODS: Twenty isolates from an outbreak of P. aeruginosa previously characterized as metallo-beta-lactamase IMP-13 producers were studied. All the isolates exhibited equal expression of the IMP-13 enzyme, but only five of them were carbapenem-resistant. It was found that the five resistant isolates lacked a outer membrane protein. The oprD and ampC genes were sequenced; the outer membrane proteins were identified using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry; the OprD and AmpC expressions, as well as the Mex efflux system, were assessed by real-time polymerase chain reaction; and finally, the contribution of reduced OprD to carbapenem resistance was determined. RESULTS: The absent outer membrane protein in group R was identified as OprD-TS; however, no variations in its expression were observed. The oprD gene presented mutations in the five resistant isolates. The production of AmpC PDC-5-type enzyme and the MexAB-OprM efflux system was the same in both carbapenem-sensitive and ‑resistant isolates. The contribution of the combined presence of IMP-13 and reduced OprD to increased resistance was examined. CONCLUSIONS: Different mechanisms contribute to carbapenem resistance in IMP-13-producing isolates. The possibility that these IMP-13-producing isolates could go undetected poses a latent risk when selecting mutants with added resistance mechanisms in order to enhance carbapenem resistance.

OBJETIVO: Identificar la proteína de membrana externa ausente en los aislamientos resistentes y determinar tanto las causas de su ausencia en la membrana, como la presencia de otros mecanismos de resistencia a carbapenemes en aislamientos clínicos de Pseudomonas aeruginosa. MÉTODOS: Se estudió un brote de 20 aislamientos de P. aeruginosa previamente caracterizados como productores de la metalobetalactamasa IMP-13. Estos aislamientos presentaron igual expresión de la enzima IMP-13, pero solo cinco de ellos fueron resistentes a carbapenemes. En esos cinco aislamientos resistentes se confirmó la ausencia de una proteína de membrana externa. Se secuenciaron oprD y ampC; se identificaron las proteínas de membrana externa por desorción/ionización láser asistida por matriz/espectometría de masa tiempo de vuelo (MALDI-TOF); se determinó el nivel de expresión de oprD, de AmpC y de los sistemas de eflujo tipo Mex, por reacción en cadena de polimerasa en tiempo real, y por último, se determinó la contribución del déficit de oprD a la resistencia a carbapenemes. RESULTADOS: La proteína de la membrana externa ausente en el grupo R (resistentes a ambos carbapenemes) fue identificada como OprD-TS, pero no se observaron variaciones en su expresión. El gen oprD presentó mutaciones en los cinco aislamientos resistentes. Se observó la misma producción de la enzima tipo AmpC PDC-5 y del sistema de eflujo Mex AB-OprM entre los aislamientos sensibles y resistentes a carbapenemes. Se analizó cómo la presencia conjunta de IMP-13 y el déficit de oprD contribuyen al aumento de la resistencia. CONCLUSIONES: Distintos mecanismos contribuyen a la resistencia de aislamientos productores de IMP-13 a carbapenemes. La posibilidad de no detectar estos aislamientos productores de IMP-13 representa un riesgo latente de selección de mutantes con mecanismos de resistencia que se suman para aumentar la resistencia a carbapenemes.

A total of 47 strains of Aereomonas isolated from patients with gastroenteritis was analized for 40 phenotypical characters and for evaluating the numeric taxonomy based on 27 discriminatory tests. It was proved that the clinical isolates showed a relative phenotypical distance and the groups of strains that had atypical profiles were compared with the type species by the present identification schemes.

Un total de 47 cepas de Aeromonas aisladas de pacientes con gastroenteritis fue analizado para 40 caracteres fenotípicos y para la evaluación de la taxonomía numérica basada en 27 pruebas discriminatorias. Se evidenció que los aislamientos clínicos mostraron una relativa distancia fenotípica y los grupos de cepas que mostraron perfiles atípicos fueron comparados con las especies tipos, mediante los actuales esquemas de identificación.