Salmonella isolates from urine cultures: serotypes and antimicrobial resistance in hospital settings

Abstract

This study investigated the serotypes and antimicrobial resistance of Salmonella isolates in urine cultures from 38 hospitalized patients. Nine serotypes were detected, and a large proportion was Typhimurium and Enteritidis. The strains presented resistance to 11 different antibiotics. Thirteen isolates (11 from serotype Typhimurium) exhibited multidrug resistance. Keywords Nontyphoid Salmonella. Urinary tract infections. Multidrug resistance Salmonella is an important pathogen causing approximately 550 million infections in the world per year [1]. Typhoid Salmonella (TS) serotypes (Typhi, Paratyphi A and B) are adapted to humans and cause typhoid fever, while nontyphoid Salmonella (NTS) serotypes infect a wide range of hosts, causing symptoms ranging from mild gastroenteritis to severe systemic infection. NTS has increasingly impacted human health, and it is responsible for approximately 93.8 million infections with 155,000 deaths per year [1, 2]. The clinical symptoms include diarrhea, fever, headache, and abdominal pain [3]. Infections by invasive NTS (iNTS) strains can also progress to severe life-threatening sepsis, a common cause of bacteremia in children and adults. The diversity in the clinical manifestations is explained by several factors, highlighting the occurrence of a large range of virulence factors in the bacterial strains [3, 4]. Urinary tract infections (UTIs) by Salmonella are infrequent in routine hospital practice and rarely reported in the scientific literature, although they may cause serious morbidity in immunocompromised and even in immunocompetent patients [5-8]. The present study describes the serotype identification and antimicrobial resistance of Salmonella isolates from urine cultures of hospitalized patients. A total of 38 Salmonella isolates were obtained from urine cultures in different hospitalized patients in Rio Grande do Sul state and sent to a public health laboratory (Laboratório Central do Rio Grande do Sul, LACEN-RS) from 2010 to 2015. Demographic data (such as hospital, city, and date of isolation; age and sex of the patients) were obtained in the clinical forms. The isolates were plated on Salmonella/ Shigella solid media, and presumptive Salmonella colonies were cultured in Triple Sugar Iron (TSI), Urea, Citrate, and Lysine Iron Agar (LIA) slants (Probac, São Paulo, Brazil). The isolates were submitted to aerobic incubation at 37°C for 24 h. Suspected Salmonella colonies were partially tested by agglutination with the main polyvalent O and H antisera (Probac, São Paulo, Brazil). Complete antigenic characterization was carried out for serotype identification in the National Reference Laboratory for Cholera and Enteric Diseases in the Institute Oswaldo Cruz (FIOCRUZ, Rio de Janeiro, RJ, Brazil) by the Kauffmann-White-Le Minor scheme [9]. All isolates were also submitted to DNA extraction and real-time polymerase chain reaction (PCR) targeting the invA

Mecanismos plasmídicos de resistencia a quinolonas, betalactámicos y colistina en Salmonella enterica. Paraguay 2020-2021

“…Si tenemos en cuenta los antimicrobianos utilizados con mayor frecuencia para el tratamiento de salmonelosis, en nuestro estudio los aislamientos humanos mostraron resistencia a ampicilina 10,6%, cotrimoxazol 3,8%, C3 a G 2,2% y ciprofloxacina 0,3% (5,2% de sensibilidad intermedia). Nuestros porcentajes son más bajos en comparación a los descritos en Brasil por Oliveira do Reis y col en el año 2019 (35) en muestras de orina ( ampicilina 31,3%, cotrimoxazol 9,4%, C3 a G y ciprofloxacina 3,1%); y Perú en estudios realizados por Quino y col. (33) donde se encontraron resistencias superiores al 50% frente a la ampicilina, cotrimoxazol y cefotaxima en aislados de muestras humanas y no humanas, con la diferencia que las cepas estudiadas en dicho trabajo fueron del serotipo Infantis. Estos resultados sugieren que existe variabilidad en la resistencia antimicrobiana entre diferentes países y regiones, lo cual puede estar influenciado por varios factores como la epidemiología de las cepas circulantes.…”