Antibiotic Resistance of Gram-Negative Bacilli Isolated from Pediatric Patients with Nosocomial Bloodstream Infections in a Mexican Tertiary Care Hospital

Abstract

Background: Gram-negative bacilli are the most common bacteria causing nosocomial bloodstream infections (NBSIs) in Latin American countries. Methods: The antibiotic resistance profiles of Gram-negative bacilli isolated from blood cultures in pediatric patients with NBSIs over a 3-year period in a tertiary care pediatric hospital in Mexico City were determined using the VITEK-2 system. Sixteen antibiotics were tested to ascertain the resistance rate and the minimum inhibitory concentration using the Clinical Laboratory Standards Institute (CLSI) broth micro-dilution method as a reference. Results: A total of 931 isolates were recovered from 847 clinically significant episodes of NBSI. Of these, 477 (51.2%) were caused by Gram-negative bacilli. The most common Gram-negative bacilli found were Klebsiella pneumoniae (30.4%), Escherichia coli (18.9%), Enterobacter cloacae (15.1%), Pseudomonas aeruginosa (9.9%), and Acinetobacter baumannii (4.6%). More than 45 and 60% of the K. pneumoniae and E. coli isolates, respectively, were resistant to cephalosporins, and 64% of the E. coli isolates were resistant to fluoroquinolones. A. baumannii exhibited low rates of resistance to antibiotics tested. In the E. cloacae and P. aeruginosa isolates, no rates of resistance higher than 38% were observed. Conclusions: In this study, we found that the proportion of NBSIs due to antibiotic-resistant organisms is increasing in a tertiary care pediatric hospital of Mexico.

Rapid Gene Turnover as a Significant Source of Genetic Variation in a Recently Seeded Population of a Healthcare-Associated Pathogen

“…With respect to the A. baumannii populations in Mexico, we are adamant that our study could be of paramount importance for future studies tackling the population genomics of this species in this country. Clearly this is not the first study analyzing A. baumannii isolates from Mexico; in fact, over the last decade there have been several studies (Ares et al, 2013 ; Morfin-Otero et al, 2013 ; Alcantar-Curiel et al, 2014 ; Bocanegra-Ibarias et al, 2015 ; Cornejo-Juarez et al, 2015 ; Gonzalez-Villoria et al, 2016 ; Tamayo-Legorreta et al, 2016 ), which have been very useful from a clinical point of view, as they focused on the molecular epidemiology (Morfin-Otero et al, 2013 ; Gonzalez-Villoria et al, 2016 ; Tamayo-Legorreta et al, 2016 ) or the antibiotic resistance profiles of hospital isolates (Ares et al, 2013 ; Alcantar-Curiel et al, 2014 ; Bocanegra-Ibarias et al, 2015 ). However, none of those studies have analyzed the genomic diversity of the isolates in question and, to the best of our knowledge, this is the first study that has addressed the genetic variation within a population of A. baumannii isolates in Mexico at a genome level.…”

H-NS Nucleoid Protein Controls Virulence Features of Klebsiella pneumoniae by Regulating the Expression of Type 3 Pili and the Capsule Polysaccharide

“…Klebsiella pneumoniae is an opportunistic Gram-negative bacterium belonging to the Enterobacteriaceae family causing nosocomial infections such as septicemia, pneumonia, urinary tract infections, surgical site infections and catheter-related infections (Han, 1995 ; Podschun and Ullmann, 1998 ; Schelenz et al, 2007 ; Ares et al, 2013 ). In addition, K. pneumoniae has been implicated in pyogenic liver abscesses in patients with meningitis, endophthalmitis and malignancies (Fung et al, 2002 ; Chang et al, 2008 ; Tsai et al, 2008 ; Alcántar-Curiel and Girón, 2015 ).…”

Photophysical and antibacterial properties of complex systems based on smectite, a cationic surfactant and methylene blue

“…The Gram-negative bacteria E. cloacae and E. coli used in this work are a frequent source of nosocomial infections in intensive care units or oncological departments, but they are also significant indicators of pollution in nature [21,22]. Additionally, the above-mentioned microorganisms are frequently resistant to conventional antimicrobial drugs or disinfectants [23].…”