Klebsiella pneumoniae ESBL producers responsible for severe UTIs in a renal transplant unit

Excerpt

The emergence of extended-spectrum β-lactamase (ESBL)-producers, along with multidrug-resistant (MDR) isolates, poses a serious problem in hospital settings [1]. ESBLs are capable of hydrolyzing penicillins, broad-spectrum cephalosporins, and aztreonam. Since the first report of ESBL-producing Klebsiella in 1983, isolated from a patient in Germany [2‐4], ESBLs have been reported worldwide [5]. There are three types, namely, SHV, TEM,  and CTX-M. In some countries (e.g., Argentina, Greece, Japan, Spain, and Taiwan), CTX-M-type ESBLS are more prevalent than TEM and SHV types [6, 7]. In Europe, where the TEM- and SHV-type ESBLs were first reported and where they remain widespread [8, 9], a rapid and massive dissemination of isolates producing CTX-M-type ESBLs has recently been reported [10, 11] and is a matter of major concern. In Italy, the presence of CTX-M-type ESBLs was reported in clinical isolates of Enterobacteriaceae from some hospitals in 2003 [12] as well as from pets in 2005 [13]. In 2003, the second Italian nationwide survey on ESBL production among Enterobacteriaceae was initiated, and the results showed that CTX-M-type enzymes were common (around 20%) among ESBL-producers [14]. The CTX-M family is recognized as a rapidly expanding family of ESBLs that selectively prefers to hydrolyze cefotaxime rather than ceftazidime [2]. However, variants of CTX-M with increased hydrolyzing activity against ceftazidime have emerged. The widespread use of antibiotics coupled with the transmissibility of resistant determinants mediated by plasmids, transposons, and gene cassettes in integrons are factors that contribute to the increase in antibiotic resistance in bacterial pathogens [15]. In renal transplant recipients, urinary tract infections (UTIs), including asymptomatic bacteriuria, cystitis, and pyelonephritis (PN), are the most common forms of bacterial infections [16]. UTIs are frequently associated with early onset chronic rejection and may lead to reduced transplantation survival [17]. Susceptibility to bacterial infection in renal transplantation recipients is directly related to the level and duration of the pharmacological immunosuppression [18]. …