Rapid Detection and Antibiotic Susceptibility of Uropathogenic Escherichia coli by Flow Cytometry.

BACKGROUND: Early preliminary data on antibiotic resistance patterns available before starting the empiric therapy of urinary tract infections (UTIs) in patients with risk factors for acquiring antibiotic resistance could improve both clinical and epidemiological outcomes. The aim of the present study was two-fold: (i) to assess the antibiotic susceptibility of uropathogenic Escherichia coli isolates, exhibiting different antibiotic resistance phenotypes, directly in artificially contaminated urine samples using a flow cytometry (FC) based protocol; (ii) to optimize the protocol on urine samples deliberately contaminated with bacterial suspensions prepared from uropathogenic E. coli strains. RESULTS: The results of the FC based antimicrobial susceptibility testing (AST) protocol were compared with the reference AST methods results (disk diffusion and broth microdilution) for establishing the sensitivity and specificity. The proposed FC protocol allowed the detection and quantification of uropathogenic E. coli strains susceptibility to nitrofurantoin, trimethoprim-sulfamethoxazole, ciprofloxacin, and ceftriaxone within 4 h after the inoculation of urine specimens. The early availability of preliminary antibiotic susceptibility results provided by direct analysis of clinical specimens could essentially contribute to a more targeted emergency therapy of UTIs in the anticipation of AST results obtained by reference methodology. CONCLUSIONS: This method will increase the therapeutic success rate and help to prevent the emergence and dissemination of drug resistant pathogens.

Molecular screening of carbapenemase-producing Gram-negative strains in Romanian intensive care units during a one year survey.

This is the first study, to our knowledge, performed on a significant number of strains (79 carbapenem-resistant Enterobacteriaceae and 84 carbapenem-resistant non-fermenting Gram-negative rods, GNRs) isolated from tissue samples taken from patients in the intensive care units of two large hospitals in Bucharest, Romania, between 2011 and 2012. The results revealed a high prevalence and great diversity of carbapenemase genes (CRG), in both fermenting and non-fermenting Gram-negative carbapenem-resistant strains. The molecular screening of carbapenem-resistant GNRs revealed the presence of worldwide-distributed CRGs (i.e. blaOXA-48 and blaNDM-1 in Enterobacteriaceae and blaOXA-23, blaVIM-4, blaOXA-10-like, blaOXA-60-like, blaSPM-like and blaGES-like in non-fermenting GNRs), reflecting the rapid evolution and spread of carbapenemase producers, particularly in hospitals. Rapid identification of the colonized or infected patients is required, as are epidemiological investigations to establish the local or imported origin of the respective strains.

Antibiotic resistance profiles of Acinetobacter sp. strains isolated from intensive-care unit patients.

UNLABELLED: Multidrug resistance and the increasing number of severe infections caused by Acinetobacter sp. strains are a major issue for intensive care units (ICUs), where patients with severe diseases and often destabilized physiological condition are admitted. The aim of this study was to investigate the antibiotic resistance profiles of 200 Acinetobacter spp. isolated from tracheal aspirates in patients admitted to ICU, Fundeni Clinical Institute (FCI). METHODS: the samples were collected from intubated patients between January 2006-December 2007. The microbial strains were identified with the help of the BD Phoenix system. The investigation of the antibiotic resistance patterns was performed by agar disk diffusion method according to CLSI recommendations, and the production of metallo-betalactamases (MBL) was confirmed by MBL E-test. RESULTS: the majority of the studied strains (80%) were multidrug resistant with a high percentage of panresistance (32%). Metallo-beta-lactamases production among the strains with resistance to imipenem was high (over 83%), these strains being also resistant to the majority of the other tested antibiotics with the exception of colistin. CONCLUSIONS: Our results confirmed that the multidrug resistance is the major threat of Acinetobacter sp. infections, especially when they occur in high risk patients.

Antibiotic resistance of Gram negative bacilli strains isolated from the Intensive Care Unit in Fundeni Clinical Institute, Bucharest, Romania.

UNLABELLED: The aim of this study was to investigate the antibiotic resistance profile of 58 Gram negative bacilli strains (GNB): 36 non-fermentative GNB (NGNB), including 19 strains of Acinetobacter spp., 11 of Pseudomonas aeruginosa, 6 of Stenotrophomonas maltophilia and 22 enterobacterial strains (14 strains of KEHSs, 6 belonging to the group Proteus-Providencia and 2 Escherichia coli) isolated from nasal, pharyngeal exudates and also from bronchial secretions, from immuno-depressed patients admitted in the Intensive Care Unit of Fundeni Clinical Institute. METHHODS: the antibiotic susceptibility testing was performed according to CLSI 2009 recommendations and the production of beta-lactamases was investigated by ESBL chromogenic media, double disc diffusion test, ESBL E-test, Amp C E-test and MBL E-test. RESULTS: 68% of the enterobacterial strains produced extended-spectrum beta- lactamases (ESBL), 13.63% of them expressing simultaneously the Amp C enzyme. All enterobacterial strains were susceptible to carbapenems (Imipenem and Ertapenem). Metallo-beta lactamases production among NGNB strains with resistance to Imipenem was high (80%), these strains being also multi-resistant to the majority of tested antibiotics with the exception of colistin. CONCLUSIONS: our results showed that the majority of the analyzed strains were multi-drug resistant. Antibiotic multi-resistance and the increasing number of severe infections caused by these strains are a major issue for ICU, where patients with severe diseases and destabilized physiological condition are often admitted.