Activity of Tedizolid and Comparator Agents Against Gram-positive Isolates Causing Skin and Skin Structure Infections in Pediatric Patients in United States Hospitals (2015-2019).

BACKGROUND: Tedizolid was approved by the United States Food and Drug Administration to treat acute bacterial skin and skin structure infections in adults in 2014, and in 2020, United States Food and Drug Administration expanded the approval of tedizolid to treat pediatric patients 12 years of age and older. This study assessed the activity of tedizolid and comparator agents against clinical surveillance isolates collected from pediatric patients with skin and skin structure infection in the United States. METHODS: A total of 2747 gram-positive organisms (1 per patient) were collected in 2015 to 2019 from pediatric (≤17 years old) patients with skin and skin structure infections. The isolates were collected from 33 US medical centers and susceptibility tested against tedizolid and comparators by reference broth microdilution methods. Susceptibility results for main pathogens were stratified by patient age: ≤1 years old (851 isolates), 2 to 5 years old (623), 6 to 12 years old (754) and 13 to 17 years old (519). RESULTS: Staphylococcus aureus (n = 2163) was the main pathogen recovered from all age groups, followed by ß-hemolytic streptococci (n = 460). Tedizolid inhibited all S. aureus , including methicillin-resistant S. aureus (MRSA) isolates (41.0%), regardless of the age group. MRSA rates varied by age group; MRSA was highest among ≤1 years old (45.0%) and lowest in the 13 to 17 years old (32.7%) groups. Linezolid, daptomycin and vancomycin also displayed susceptibility rates of 100% against S. aureus isolates. Clindamycin (81.3%-98.5%), tetracycline (91.6%-97.1%) and trimethoprim-sulfamethoxazole (97.0%-100%) susceptibility rates varied among age groups and methicillin resistance profiles. Overall, tedizolid, linezolid, daptomycin and vancomycin inhibited all gram-positive pathogens in this collection. CONCLUSIONS: Tedizolid was very active against a large collection of gram-positive pathogens causing skin and skin structure infection in pediatric patients, including MRSA isolates.

Carriage of methicillin-resistant Staphylococcus aureus in children in Brazil.

The extent of methicillin-resistant Staphylococcus aureus (MRSA) carriage in Brazilian infants is largely unknown. We evaluated the presence of MRSA nasopharyngeal (NP) carriage in 686 children younger than 5 years with respiratory tract infection (609) and meningitis (77). S. aureus was isolated in 93 (13.5%) NP specimens of which 7 (1.02%) were identified as MRSA (oxacillin MIC, >256 microg/mL) harboring SCCmec type III. The dendrogram derived from the pulsed-field gel electrophoresis gel images showed that the MRSA strains diverged from the Brazilian endemic hospital-acquired clones from 10.4% to 21.7%. Although the MRSA strains were recovered from children within the first 6 h of their admission to hospital, the presence of SCCmec type III along with the multidrug-resistant profile of the isolates raises the hypotheses that these MRSA strains may have hospital origin and are now spreading into the pediatric community as colonizing pathogens.

Risk factors for vancomycin-resistant Enterococcus faecalis bacteremia in hospitalized patients: an analysis of two case-control studies.

BACKGROUND: Vancomycin-resistant enterococci (VRE) is an important pathogen in the hospital environment, and a progressive increase in its incidence is a cause of nosocomial infections. Bacteremia is one of the major infections caused by this pathogen. Risk factors for VRE bacteremia were assessed at a university-affiliated hospital. METHODS: Two case-control studies with different control groups were used. In study 1, patients with VRE bacteremia were compared with control patients matched by sex, admission unit, age (+/-10 years), and time of admission (+/-1 year). In study 2, the case group (VRE patients) was compared with vancomycin-susceptible enterococci (VSE) patients. RESULTS: A total of 34 patients with VRE bacteremia and 102 control patients were included in study 1, and 34 patients with VRE bacteremia and 55 patients with VSE bacteremia were included in study 2. In study 1, vancomycin use (OR, 10.19; CI 95%, 3.63-28.57) was associated with VRE bacteremia. In study 2, vancomycin use (OR, 17.58; CI 95%, 5.24-58.96) was also associated with VRE bacteremia. CONCLUSION: Because vancomycin use was the only variable associated with VRE bacteremia in the two studies, we confirmed that vancomycin exposure is the major risk factor for VRE bacteremia.

Metalo-beta-lactamases / Metallo-beta-lactamases

Nos últimos anos tem sido observada maior incidência de bacilos Gram-negativos resistentes a cefalosporinas de espectro ampliado no ambiente hospitalar, ocasionando, assim, maior uso de betalactâmicos mais potentes, como os carbapenens. A utilização de carbapenens exerce maior pressão seletiva sobre a microbiota hospitalar, o que pode ocasionar aumento da resistência a esses agentes. Entre os mecanismos de resistência a carbapenens mais comumente identificados estão a produção de betalactamases, como, por exemplo, as pertencentes à classe D de Ambler e as que pertencem à classe B de Ambler, ou metalo-beta-lactamases (MbetaL). Essas últimas hidrolisam todos betalactâmicos comercialmente disponíveis, sendo a única exceção o monobactam aztreonam. Desde o início da década de 1990, novos genes que codificam MbetaLs têm sido descritos em microrganismos clinicamente importantes, como Pseudomonas spp., Acinetobacter spp. e membros da família Enterobacteriaceae. O encontro desses microrganismos não-sensíveis a carbapenens pode ser submetido a metodologias fenotípicas para detecção da produção de MbetaL com o intuito de auxiliar a Comissão de Controle de Infecção Hospitalar (CCIH) e prevenir a disseminação desses determinantes de resistência, uma vez que genes que codificam MbetaLs estão contidos em estruturas genéticas que propiciam sua mobilidade de forma muito efetiva, sendo então facilmente disseminados.