Newborn intestinal colonization by multidrug resistant enterobacteria in a neonatal unit

Abstract

Objective: To evaluate the occurrence of intestinal colonization in newborns by multidrug-resistant enterobacteria strains (MDRES) during hospital stay after birth. We used selective media in an attempt to determine the relationship between isolation of these strains and some of the presumed colonization risk factors. Method: A sequencial inclusion study of 30 newborns was carried out in the neonatal unit of the HUPE, State University Hospital, a general 600-bed tertiary care hospital. We obtained clinical and epidemiological information from medical records and collected a fecal sample from each newborn, which was plated in gentamicin (8mg/ml) medium and potassium tellurite (25mg/ml) medium. The isolated strains were biochemically identified and also submitted to tests of antimicrobial susceptibility. Nine MDRES were submitted to an assay for plasmid conjugational transfer. Results: We isolated 56 distinct MDRES from 14 among 30 newborns (46.7%). Klebsiella pneumoniae was the most common bacterial species (38/56 (68%)). We found statistical association between individual MDRES isolation and presence of 3 or 4 of the following colonization risk factors considered: antimicrobial use, low weight (<2.500g), more than 6 days of hospitalization and artificial milk feeding (p< 0.02). We could detect plasmid resistance transfer by bacterial conjugation for 8 among 9 MDRES. Conclusion: The seletive cultura media were useful to detect the high frequence of newborns colonized by MDRES in association with well established infection risk factors. We emphasize the importance of reinforcing control rules aiming at preventing intestinal colonization viewed as a risk of nosocomial infection.

Antimicrobial resistance in Gram-negative bacilli isolated from infant formulas

“…pneumoniae is one of the most important nosocomial pathogens [17]. Colonization of newborns with multiresistant K. pneumoniae has been associated with arti¢cial feeding [6]. The environmental species K. planticola was the fourth more frequently isolated microorganism from IF samples in this study.…”

“…Studies conducted in England, Belgium and Spain have demonstrated that bacterial strains with indistinct plasmid pro¢les and antimicrobial susceptibility patterns were isolated from enteral formulas and from blood of patients who had received the formula [2,4,5]. Furthermore, a statistical association was found between the intestinal colonization of hospitalized children with multiresistant bacteria and arti-¢cial milk feedings, antimicrobial use, low weight and long periods of hospitalization [6].…”

“…There is evidence showing phenotypic and genotypic similarities between isolates from human infections and those recovered from food and nutritional formulas given to hospitalized patients [2,4,5]. Furthermore, a statistical association was found between the intestinal colonization of hospitalized children with multiresistant bacteria and arti-¢cial milk feedings, antimicrobial use, low weight and long periods of hospitalization [6]. Furthermore, a statistical association was found between the intestinal colonization of hospitalized children with multiresistant bacteria and arti-¢cial milk feedings, antimicrobial use, low weight and long periods of hospitalization [6].…”

Dissemination of antimicrobial resistance and Potassium Tellurite (PT) in the hospital environment: can the use of means with Tellurite and the detection of insertion sequences contribute to prevention and intervention?

“…Maltman & Yurkov (2019) report bacterial lethality at concentrations as low as 1 µg/mL. However, the concentration of 25 µg/mL, used by us, seems advantageous, considering that with this concentration, we have obtained conditions for the selection of transconjugant strains resistant to PT (Vieira et al, 1999). Growth at 25 µg/mL, then, suggests plasmid resistance.…”

“…Since PT resistance is common in many Gram negative and Gram positive bacteria, such as Staphylococcus aureus, Corynebacterium sp., Yersinia pestis and Shiga toxin-producing E. coli, the use of PT in selective culture media has been applied by many years in the isolation of pathogens, (Orth et al, 2007). In previous investigations, culture media containing antimicrobials (gentamicin 8 µg/ml) or potassium tellurite (25 μg/ml) contributed to the isolation of multidrugresistant Enterobacteriaceae strains in patients with risk factors associated with colonization and risk of infection (Vieira, et al, 1999;Melo et al, 1993, Gonçalves et al, 2015.…”