Carbapenem-Resistant but Cephalosporin-Susceptible Pseudomonas aeruginosa in Urinary Tract Infections: Opportunity for Colistin Sparing

Abstract

This paper briefly reports the occurrence and epidemiology of carbapenem-resistant but cephalosporin-susceptible (Car-R/Ceph-S) Pseudomonas aeruginosa isolates from urinary tract infections (UTIs) in a tertiary-care hospital in the Southern Region of Hungary, and the phenotypic characterization of the possible resistance mechanisms in these isolates. Isolates and data were collected regarding P. aeruginosa UTIs corresponding to the period between 2008 and 2017. Susceptibility testing was performed using the Kirby–Bauer disk diffusion method; minimum inhibitory concentrations (MICs) of the isolates were determined using E-tests. The phenotypic detection of ampicillin C-type (AmpC) β-lactamases, efflux pump overexpression and carbapenemase production was also performed. P. aeruginosa represented n = 575 (2.72% ± 0.64%) from outpatient, and n = 1045 (5.43% ± 0.81%) from inpatient urinary samples, respectively. Based on the disk diffusion test, n = 359 (22.16%) were carbapenem-resistant; in addition to carbapenems, n = (64.34%) were also resistant to ciprofloxacin; n = (60.17%) to gentamicin/tobramycin; n = (58.51%) to levofloxacin; and n = (27.57%) to amikacin. From among the carbapenem-resistant isolates, n = 56 (15.59%) isolates were multidrug-resistant, while n = 16 (4.46%) were extensively drug-resistant. From among the Car-R/Ceph-S isolates (n = 57), overexpression of AmpC was observed in n = 7 cases (12.28%); carbapenemase production in n = 4 (7.02%); while overexpression of efflux pumps was present in n = 31 (54.39%) isolates. To spare last-resort agents, e.g., colistin, the use of broad-spectrum cephalosporins or safe, alternative agents should be considered in these infections.

Prevalence and Antibiotic Resistance of ESKAPE Pathogens Isolated in the Emergency Department of a Tertiary Care Teaching Hospital in Hungary: A 5-Year Retrospective Survey

“…Interestingly, meropenem susceptibility of P. aeruginosa was slightly lower than susceptibility to third generation cephalosporins. The presence of carbapenem-resistant but cephalosporin-susceptible (Car-R/Ceph-S) P. aeruginosa strains has been already reported from our university [ 54 ].…”

It’s Not Easy Being Green: A Narrative Review on the Microbiology, Virulence and Therapeutic Prospects of Multidrug-Resistant Pseudomonas aeruginosa

“…In one the most recent studies on the topic from Southern Hungary, the occurrence of Car-R/Ceph-S P. aeruginosa from UTIs was assessed over a 10-year surveillance period. Overall, fifty-seven such isolates were detected and these bacteria were characterized with phenotypic methods: 4/57 isolates produced carbapenemases, 7/57 isolates showed the overproduction of an AmpC β-lactamase, 31/57 overexpressed efflux pumps, while in the case of 15/57 isolates, no conclusive data could be obtained for the resistance determinants using the phenotypic methods included [244]. Interestingly, the first identified integronborne MBL was also identified from P. aeruginosa in Hungary [245].…”

“…Even though there is growing literature available on the topic, there is no consensus on the most common mechanisms of resistance contributing to the emergence of Car-R/Ceph-S isolates. There are wide-ranging differences in the prevalence of carbapenemases (especially for MBLs), and this may affect the susceptibility to cephalosporins as well [73,[230][231][232][233][234][235][236][237][238][239][240][241][242][243][244]. Khalili et al proposed that the detection of Car-R/Ceph-S isolates is dependent on the absence of carbapenemases [240].…”

Diversity and Distribution of Resistance Markers in Pseudomonas aeruginosa International High-Risk Clones

“…The most frequently reported beta-lactamases in P. aeuginosa are ESBLs (e.g., PER, GES, VEB enzymes), OXA-type beta-lactamases, and metallo-beta-lactamases (MBLs) namely, IMP, VIM, NDM types [ 21 , 22 ]. Uncommon carbapenem resistance phenotype in P. aeruginosa has been also reported namely, carbapenem resistance with maintained cefalosporin susceptibility [ 23 , 24 ]. Aminoglycoside-modifying enzymes are also commonly detected in P. aeruginosa namely, aacA4 , aadA7 , aph(3′)-IIb [ 25 , 26 , 27 ].…”