Genetic Relatedness among Extended-Spectrum β-Lactamase-ProducingKlebsiella pneumoniaeOutbreak Isolates Associated with Colonization and Invasive Disease in a Neonatal Intensive Care Unit

Abstract

Pulsed-field gel electrophoresis typing of 60 extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBLKp) isolates obtained in a neonatal intensive care unit during an outbreak indicated the dissemination of two major bacterial genotypes associated with colonization and invasive disease: one composed by aminoglycoside-resistant isolates and the other by aminoglycoside-susceptible isolates. A urease-negative phenotype was observed among aminoglycoside-resistant ESBLKp. Six pairs of isolates from gastrointestinal (GI) colonization and isolates from invasive disease that occurred 3-23 days later were shown to belong to the same genotype, reinforcing a direct association between colonization and subsequent disease. These data indicate that screening for ESBLKp GI colonization in an outbreak setting may be useful to detect neonates at a higher risk of invasive disease.

Colonization and Persistence of Antibiotic-Resistant Enterobacteriaceae Strains in Infants Nursed in Two Neonatal Intensive Care Units in East London, United Kingdom

“…In a report from Washington, DC, 17% of infants admitted to a NICU became colonized with antibiotic-resistant Enterobacteriaceae strains, and 14% of colonized infants developed infection (36). A temporal relationship of colonization preceding bloodstream infection with Enterobacteriaceae strains also has been described (6). In this study, the colonization of infants early in life with MRE was frequent, but despite this there were few episodes of bacteremia associated with MRE (during the inpatient stay).…”

Klebsiella pneumoniae Translocates across the Intestinal Epithelium via Rho GTPase- and Phosphatidylinositol 3-Kinase/Akt-Dependent Cell Invasion

“…Therefore, these clinical K. pneumoniae strains possibly penetrated monolayers without causing obvious disruptions of monolayer integrity or paracellular permeability. K. pneumoniae belongs to human microbiota, and the gut resident strains have been shown to share genotypes similar to those the liver abscess and bacteremia strains (13)(14)(15). We suggest that this transcellular translocation mechanism is exploited generally by K. pneumoniae strains from the gut flora to cause systemic infections.…”

“…A seroepidemiological survey of K. pneumoniae cells that have colonized the gastrointestinal tract showed that capsular types K1 and K2 were the most prevalent and were responsible for 9.8% of a total of 592 fecal isolates from healthy Chinese adults in Asian countries (10). Epidemiological studies have suggested that most K. pneumoniae infections are preceded by colonization of the gastrointestinal tract (11)(12)(13)(14)(15). Clinical capsular typing and pulsedfield gel electrophoresis analysis revealed a similarity in strain serotypes and genotypes of K. pneumoniae fecal isolates from healthy carriers and patients with liver abscess (13).…”

“…Studies of ESBL-producing K. pneumoniae strains demonstrated the genetic relatedness among outbreak isolates obtained from prior colonization events and subsequent diseases (14,15). A hypothesis that gut-derived K. pneumoniae causes infections has been proposed; however, the potential mechanistic details involved have not been elucidated.…”

Clonal Dissemination of Extended-Spectrum β-Lactamase (ESBL)-Producing Klebsiella pneumoniae Isolates in a Korean Hospital

“…Several molecular methods have been used for characterizing K. pneumoniae isolates such as randomly amplified polymorphic DNA analysis, pulsed-field gel electrophoresis, and amplified fragment length polymorphism (5-7). However, these methods are band-based and so the results may be ambiguous, but generally these methods are well suited for local epidemiologic investigation.…”