High Prevalence of Gut Microbiota Colonization with Broad-Spectrum Cephalosporin Resistant Enterobacteriaceae in a Tunisian Intensive Care Unit

Abstract

Healthcare-associated infections due to cefotaxime-resistant (CTX-R) Enterobacteriaceae have become a major public health threat, especially in intensive care units (ICUs). Often acquired nosocomially, CTX-R Enterobacteriaceae can be introduced initially by patients at admission. This study aimed to determine the prevalence and genetic characteristics of CTX-R Enterobacteriaceae-intestinal carriage in ICU patients, to evaluate the rate of acquisition of these organisms during hospitalization, and to explore some of the associated risk factors for both carriage and acquisition. Between December 2014 and February 2015, the 63 patients admitted in the ICU of Charles Nicolle hospital were screened for rectal CTX-R Enterobacteriaceae colonization at admission and once weekly thereafter to identify acquisition. CTX-R Enterobacteriaceae fecal carriage rate was 20.63% (13/63) at admission. Among the 50 non-carriers, 35 were resampled during their hospitalization and the acquisition rate was 42.85% (15/35). Overall, 35 CTX-R Enterobacteriaceae isolates were collected from 28 patients (25 Klebsiella pneumoniae, seven Escherichia coli, and three Enterobacter cloacae strains). Seven patients were simultaneously colonized with two CTX-R Enterobacteriaceae isolates. CTX-M-15 was detected in most of the CTX-R Enterobacteriaceae isolates (30/35, 88.23%). Three strains co-produced CMY-4 and 22 strains were carbapenem-resistant and co-produced a carbapenemase [OXA-48 (n = 13) or NDM-1 (n = 6)]. Molecular typing of K. pneumoniae strains, revealed eight Pulsed field gel electrophoresis (PFGE) patterns and four sequence types (ST) [ST101, ST147, ST429, and ST336]. However, E. coli isolates were genetically unrelated and belonged to A (n = 2), B1 (n = 2) and B2 (n = 3) phylogenetic groups and to ST131 (two strains), ST572 (two strains), ST615 (one strain) and ST617 (one strain). Five colonized patients were infected by CTX-R Enterobacteriaceae (four with the same strain identified from their rectal swab and one with a different strain). Whether imported or acquired during the stay in the ICU, colonization by CTX-R Enterobacteriaceae is a major risk factor for the occurrence of serious nosocomial infections. Their systematic screening in fecal carriage is mandatory to prevent the spread of these multidrug resistant bacteria.

Carriage of multidrug-resistant bacteria among pediatric patients before and during their hospitalization in a tertiary pediatric unit in Tunisia

“…Most studies have shown that a long hospital stay increases the risk for colonization or infection with MDR bacteria [2,5]. In fact, Day 30 to screen patients was chosen, on the basis of those studies.…”

“…The isolates were then screened for ESBL production using both the resistance phenotype and the double-disk synergy test by the use of conventional combination [5]. …”

“…A group of international experts came together through a joint initiative by the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC), to create a standardized international terminology with which to describe acquired resistance profiles in Staphylococcus aureus, Enterococcus spp., Enterobacteriaceae (other than Salmonella and Shigella), Pseudomonas aeruginosa and Acinetobacter spp., all bacteria often responsible for healthcare-associated infections and prone to multidrug resistance [4]. A recent study emphasized the importance of identifying individuals carrying antimicrobial resistant bacteria in both patient and healthy populations [5]. Hospitalization per se is known to predispose to colonization, and those heading to poor regions are more likely to be hospitalized than those opting for high-income countries [6].…”

Long-lasting outbreak due to CTX-M-15-producing Klebsiella pneumoniae ST336 in a rehabilitation ward: report and literature review

“…K. pneumoniae isolates of clonal complex 17 are well recognized contributors to the spread of CTX-M-15 worldwide [31] and ST336 is among the less prevalent yet international clones that have been associated with the spread of various ESBL enzymes, including CTX-M-15, and even carbapenemase resistance [23,32,33]. K. pneumoniae ST336 has been reported in blood, urine, stool, exudate, intraabdominal and respiratory tract specimens and an unknown specimen from 45 patients in North America, Europe and Asia [27,28,[31][32][33][34][35][36]. While 14 of the cases were sporadic and seemingly unrelated, one Portuguese study revealed an almost yearlong nosocomial and clonal outbreak that affected mostly kidney transplant patients and patients with urinary tract disorders; the organism was isolated from urine in 27 of the 31 case patients [31].…”

“…Virulence factors were studied in eight of the 45 reported isolates of K. pneumoniae ST336. An intraabdominal isolate was found to encode type 1 fimbriae [32], which are common in the species and essential for the development of urinary tract infections [37], and a faecal isolate was found to encode type 3 fimbriae, responsible for biofilm formation [38], and the siderophores enterobactin and yersiniabactin [36]. Six isolates from blood were negative for the capsular antigens K-1 and K-2, which may be associated with hypervirulence in some clonal complexes [39].…”