Resistencia antimicrobiana de uropatógenos en adultos mayores / Antimicrobial resistance of uropathogens in older adults

Introducción: En la actualidad, la resistencia antimicrobiana ha sido declarada por la Organización Mundial de la Salud como un problema de salud pública. Objetivo: Determinar el perfil de resistencia antimicrobiana de uropatógenos en adultos mayores. Métodos: Estudio descriptivo transversal de 567 urocultivos positivos de adultos mayores atendidos durante el año 2017 en una clínica privada en Lima, Perú. El análisis univariado se realizó por distribución de frecuencias, promedio y desviación estándar. Se estimó la asociación entre la producción de BLEE con respecto a las características epidemiológicas y el tipo de atención mediante Chi cuadrado con un nivel de significación de 0,05. Resultados: La edad promedio de la población fue de 74,1 años (DE:10,7). El 71,8 por ciento de los urocultivos positivos pertenecieron al sexo femenino. Los principales uropatógenos aislados en todos los niveles de atención fueron: E. coli, E. coli BLEE y K. pneumoniae BLEE. La E. coli presentó 69,3 por ciento de resistencia a ampicilina; y la E. coli BLEE tuvo el 100 por ciento de resistencia a ampicilina, ceftriaxona y ceftazidima. El 62 por ciento de microorganismos BLEE se encontraron en la atención ambulatoria. Se evidenció asociación estadísticamente significativa entre los agentes productores de BLEE y el sexo (p=0,004), mas no respecto al tipo de atención (p=0,144) ni subgrupos de edad (p=0,669). Conclusiones: La resistencia antimicrobiana es altamente prevalente en los adultos mayores. El sexo femenino fue el más afectado y el uropatógeno más frecuente la E. coli, este presenta una alta resistencia a ampicilina y mayor sensibilidad a nitrofurantoína. Se determinó un alto porcentaje de agentes productores de BLEE en la atención ambulatoria(AU)

Introduction: At present, the World Health Organization as a public health problem has declared antimicrobial resistance. Objective: To determine the antimicrobial resistance profile of uropathogens in older adults. Methods: Cross-sectional descriptive study of 567 positive urine cultures from older adults treated during 2017 in a private clinic in Lima, Peru. Univariate analysis was performed by frequency distribution, mean and standard deviation. The association between ESBL production with respect to epidemiological characteristics and type of care is estimated using Chi square with a significance level of 0.05. Results: The average age of the population was 74.1 years (SD: 10.7). 71.8percent of the positive urine cultures were from female sex. The main uropathogens isolated at all levels of care were E. coli, E. coli ESBL and K. pneumoniae ESBL. E. coli showed 69.3percent resistance to ampicillin; and E. coli ESBL had 100percent resistance to ampicillin, ceftriaxone, and ceftazidime. 62percent of ESBL microorganisms were found in outpatient care. There was a statistically significant association between ESBL-producing agents and gender (p = 0.004), but not with regard to type of care (p = 0.144) or age subgroups (p = 0.669). Conclusions: Antimicrobial resistance is highly prevalent in older adults. The female sex was the most affected and the most frequent uropathogen was E. coli, highly resistant to ampicillin and greater sensitivity to nitrofurantoin. High percentage of ESBL-producing agents was determined in outpatient care(AU)

Quinolone resistance and ornithine decarboxylation activity in lactose-negative Escherichia coli

Quinolones and fluoroquinolones are widely used to treat uropathogenic Escherichia coli infections. Bacterial resistance to these antimicrobials primarily involves mutations in gyrA and parC genes. To date, no studies have examined the potential relationship between biochemical characteristics and quinolone resistance in uropathogenic E. coli strains. The present work analyzed the quinolone sensitivity and biochemical activities of fifty-eight lactose-negative uropathogenic E. coli strains. A high percentage of the isolates (48.3%) was found to be resistant to at least one of the tested quinolones, and DNA sequencing revealed quinolone resistant determining region gyrA and parC mutations in the multi-resistant isolates. Statistical analyses suggested that the lack of ornithine decarboxylase (ODC) activity is correlated with quinolone resistance. Despite the low number of isolates examined, this is the first study correlating these characteristics in lactose-negative E. coli isolates.

Pentacyclic triterpenes combined with ciprofloxacin help to eradicate the biofilm formed in vitro by Escherichia coli.

Background & objectives: Ciprofloxacin is commonly used in clinical practice for the treatment of recurrent urinary tract infections caused by Escherichia coli. However, very often these recurrent infections are due to a failure in a complete eradication of the microorganisms colonizing the urinary tract, especially in catheterized patients. To enhance the bactericidal activity of ciprofloxacin against biofilm-forming uropathogenic E. coli (UPECs), we examined its effect in combination with two pentacyclic triterpenes – asiatic and ursolic acids. Methods: The anti-biofilm activity of ciprofloxacin and pentacyclic triterpenes - asiatic acid (AA) and ursolic acid (UA), as well as their synergistic effect were tested on two types of surfaces - polystyrene microtiter plates and silicone catheters. It was investigated using the time-killing and biofilm assays. Results: anti-biofilm activity of ciprofloxacin was not observed on microtiter plates or on the catheters. Ciprofloxacin combined with ursolic acid inhibited the biofilm formation on microtitre plates. This mixture, however, did not express such a strong activity against the synthesis of biofilm on the surface of catheters. Ciprofloxacin combined with asiatic acid had very weak inhibiting effect on the synthesis of biofilm mass on microtitre plates as well as on the catheters. Despite this, both mixtures – ciprofloxacin and asiatic acid, as well as ciprofloxacin and ursolic acid, exhibited strong and significant impact on the eradication of mature biofilm (P < 0.05). Interpretation & conclusions: Although ciprofloxacin is recommended in the treatment of urinary tract infections caused by UPECs, but its efficacy is arguable. Subinhibitory concentrations of ciprofloxacin did not inhibit the formation of biofilm. Pentacyclic triterpenes used in combination with ciprofloxacin enhanced its anti-biofilm effectiveness. However, this anti-biofilm activity was found to depend on the type of surface on which biofilm was formed.

Antimicrobial Susceptibility Pattern and ESBL Production among Uropathogenic Escherichia coli Isolated from UTI Children in Pediatric Unit of a Hospital in Kerman, Iran.

Aims: Emergence of antibiotic resistance and extended spectrum β- lactamase (ESBL) among uropathogens in the pediatric unit of hospitals created serious health care concern. This study deals with antimicrobial susceptibility and ESBL analysis of uropathogenic Escherichia coli isolated from children hospitalized in pediatric unit of a university hospital in Kerman, Iran. Methodology: Fifty-five uropathogens positive samples were recovered from one hundred thirty five samples collected from urine of the children hospitalized with sign of UTI in pediatric unit of a hospital, in Kerman, Iran from April 2011 to November 2012. Preliminary antimicrobial susceptibility testing was carried out using agar disk-diffusion breakpoint assay and minimum inhibitory concentrations (MICs) of different antibiotics were determined by agar dilution method. ESBL production was detected by a double disk synergy test and confirmed by a phenotypic confirmatory test. Results: Of fifty-five positive samples isolated, Escherichia coli (69%) was the leading uropathogen followed by Klebsiella spp. (18.8%), Proteus (7.27%), Staphylococcus aureus (3.63%), Citrobacter (1.8%), Enterobacter spp. (1.81%) and Enterococcus (1.8%). Antimicrobial susceptibility tests revealed that almost all uropathogenic E. coli were sensitive to carbapenems (100%) and amikacin (94.4%), while, 100% of the strains were resistant to ampicillin (MIC range ±32 μg/mL), 63.8% were resistant to amoxicillin/clavulanic acid (MIC range ±32μg/mL), 33% were resistant to trimethoprim- sulfamethoxazole (MIC range ±64.2μg/mL) and 61.1% of the strains were resistant to third generation of cephalosporins (MIC range ±8.0μg/mL) (P=0.05). The ESBL confirmatory test for uropathogenic E. coli isolates resistant to third generation of cephalosporins revealed that only 20% were produced detectable ESBL enzymes. Conclusion: From above results it can be concluded that E. coli was the most common nosocomial pathogen associated with UTI among hospitalized children in our hospital and amikacin, carbapenems were very effective drugs for treatment of UTI in these age group, while, care must be taken when third generation of cephalosporins and trimethoprimsulfamethoxazole are administered.