Ana Carolina Ramos

Influence of Culture Media on Detection of Carbapenem Hydrolysis by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

ABSTRACT In this study, we evaluated the influence of distinct bacterial growth media on detection of carbapenemase hydrolysis by matrix-assisted laser desorption ionization–time of flight mass spectrometry. False-negative results were observed for OXA-25-, OXA-26-, and OXA-72-producing Acinetobacter baumannii isolates grown on MacConkey agar medium. The other culture media showed 100% sensitivity and 100% specificity for detecting carbapenemase.

Comparison of phenotypic tests for detecting BKC-1-producing Enterobacteriaceae isolates

Carbapenemase-producing Enterobacteriaceae may exhibit in vitro susceptibility to carbapenems, especially those producing weak carbapenemases. Routine clinical laboratories have employed phenotypic tests for screening such isolates. BKC-1 is a recently reported carbapenemase that shows weak carbapenemase activity. In this study, we aimed to evaluate the behavior of distinct phenotypic methods against BKC-1-producing Enterobacteriaceae.

Identification of São Paulo metallo-beta-lactamase-1-producing Pseudomonas aeruginosa in the Central-West region of Brazil: a case study

Metallo-beta-lactamase production is an important mechanism for carbapenem resistance of Pseudomonas aeruginosa , which represents an emerging public health challenge. We report the case of a patient admitted to an intensive care unit, with sepsis caused by multidrug-resistant São Paulo Metallo-beta-lactamase-1-producing P. aeruginosa . This is the first case of infection by this pathogenic strain in the State of Mato Grosso do Sul, Brazil. Thus, infection control measures are required for preventing future spread and outbreaks.

Evaluation of a rapid immunochromatographic test for detection of distinct variants of Klebsiella pneumoniae carbapenemase (KPC) in Enterobacteriaceae

The rapid detection of KPC-producing Enterobacteriaceae by microbiology laboratories has been required for infectious control programs. Herein we evaluated the performance of a novel immunochromatographic test for detecting KPC-2-, KPC-3-, KPC-4-, KPC-6-, KPC-7-, KPC-8-, and KPC-11-producing isolates and the influence of different growth media on the test performance.

Rapid detection of ceftazidime/avibactam resistance by MALDI-TOF MS

Microbiology Section, Discipline of Laboratory Medicine, Internal Medicine Department, Universidade Federal de S~ ao Paulo (UNIFESP), S~ ao Paulo, SP, Brazil; Alerta Laboratory, Discipline of Infectious Diseases, Internal Medicine Department, Universidade Federal de S~ ao Paulo (UNIFESP), S~ ao Paulo, SP, Brazil; Department of Biophysics, Universidade Federal de S~ ao Paulo (UNIFESP), S~ ao Paulo, SP, Brazil

Rapid detection of blaKPC directly from surveillance rectal swabs by EasyQ KPC

The performance of EasyQ KPC assay was evaluated for the first time for blaKPC detection directly from surveillance rectal swabs without broth enrichment. Using conventional polymerase chain reaction as gold standard method, EasyQ KPC and culture-based molecular tests demonstrated a sensitivity/specificity of 100%/87.3% and 83.3%/98.2%, respectively.

Detection and analysis of different interactions between resistance mechanisms and carbapenems in clinical isolates of Klebsiella pneumoniae

Carbapenems are considered last-line agents for the treatment of serious infections caused by Klebsiella pneumoniae, and this microorganism may exhibit resistance to β-lactam antibiotics due to different mechanisms of resistance. We evaluated 27 isolates of K. pneumoniae resistant to carbapenems recovered from inpatients at the University Hospital of Santa Maria-RS from July 2013 to August 2014. We carried out antimicrobial susceptibility, carbapenemase detection, testing for the presence of efflux pump by broth microdilution and loss of porin by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Genetic similarity was evaluated by ERIC-PCR. High levels of resistance were verified by the minimum inhibitory concentration for the antimicrobials tested. The blaKPC gene was present in 89% of the clinical isolates. Blue-Carba and combined disk with AFB tests showed 100% concordance, while the combined disk test with EDTA showed a high number of false-positives (48%) compared with the gold-standard genotypic test. Four isolates showed a phenotypic resistance profile consistent with the overexpression of the efflux pump, and all clinical isolates had lost one or both porins. The ERIC-PCR dendrogram demonstrated the presence of nine clusters. The main mechanism of resistance to carbapenems found in the assessed isolates was the presence of the blaKPC gene.

Dissemination of multidrug-resistantProteus mirabilisclones carrying a novel integron-borneblaIMP-1in a tertiary hospital

ABSTRACT This study aimed to characterize multidrug-resistant Proteus mirabilis clones carrying a novel class 1 integron-borne blaIMP-1. In1359 was inserted into a large conjugative plasmid that also carried blaCTX-M-2. The production of carbapenemases in Enterobacteriaceae that are intrinsically resistant to polymyxins and tigecycline is very worrisome, representing a serious challenge to clinicians and infection control teams.