Use of Whole Genome Sequencing for the Molecular Comparison of Neisseria gonorrhoeae Isolates With Decreased Susceptibility to Extended Spectrum Cephalosporins From 2 Geographically Different Regions in America.

BACKGROUND: Neisseria gonorrhoeae isolates with reduced susceptibility or resistance to the recommended first-line antimicrobial therapy have been described in several countries. The purpose of this study was to use genome analyses to compare the molecular characteristics of N. gonorrhoeae isolates with decreased susceptibility to extended-spectrum cephalosporin from Ontario, Canada, and Argentina. METHODS: A total of 128 N. gonorrhoeae isolates, collected in 2015, were included. The susceptibility to penicillin G, tetracycline, ciprofloxacin, cefixime, ceftriaxone, and azithromycin was determined using the agar dilution method. Isolates were subjected to whole genome sequencing, and an in silico analysis was performed to identify antimicrobial resistance determinants and for genotyping. RESULTS: Decreased susceptibility to extended-spectrum cephalosporin was mainly associated with penA mosaic allele 34.001, together with an mtrR promoter A deletion and porB1b alterations G120K/A121N. N. gonorrhoeae multiantigen sequence typing ST1407 or closely related genotypes were identified circulating in both regions. CONCLUSIONS: An international multi-drug resistant clone of N. gonorrhoeae was associated with decreased susceptibility to extended-spectrum cephalosporin (ESC) in 2 different regions in America. Evidence of clonal dissemination of the organism in some regions suggests that the strength of surveillance programs and establishment of collaborative projects are essential.

[Capability of national reference laboratories in Latin America to detect emerging resistance mechanisms]. / Capacidad de los laboratorios nacionales de referencia en Latinoamérica para detectar mecanismos de resistencia emergentes.

OBJECTIVE: To evaluate the capability of 17 national reference laboratories participating in the Latin American Quality Control Program in Bacteriology and Antibiotic Resistance (LA-EQAS) to detect emerging resistance mechanisms- namely: resistance of enterobacteria to carbapenems due to the presence of Klebsiella pneumoniae carbapenemase (KPC) and metallo-beta-lactamase (MBL) type IMP, and intermediate resistance of Staphylococcus aureus isolates to vancomycin (vancomycin-intermediate resistant S. aureus-VISA). METHODS: The following three isolates were sent to the 17 participating LA-EQAS laboratories: KPC -producing Klebsiella pneumoniae PAHO-161, IMP-producing Enterobacter cloacae PAHO-166, and S. aureus PAHO-165 with intermediate resistance to vancomycin. Performance of each of the following operations was evaluated: interpretation of sensitivity tests, detection of the resistance mechanism, and assessment of either inhibition halo size (disk diffusion method) or minimum inhibitory concentration (MIC). RESULTS: Concordance in the detection of resistance mechanisms was 76.4%, 73.3%, and 66.7% for the K. pneumoniae PAHO-161, E. cloacae PAHO-166, and S. aureus PAHO-165 strains, respectively. Concordance between the inhibition areas observed by the participating laboratories and the ranges established by the coordinating laboratory was acceptable for all three isolates, at 90.8%, 92.8%, and 88.9%, respectively. CONCLUSIONS: Overall concordance in on the detection of KPC, MBL, and VISA resistance mechanisms was 72.1%. We consider the national reference laboratories in Latin America capable of recognizing these emerging resistance mechanisms and expect that maximum levels of concordance will be reached in the future.

Detection, treatment, and prevention of carbapenemase-producing Enterobacteriaceae: recommendations from an International Working Group.

The prevalence of carbapenemase-producing Enterobacteriaceae (CPE) has increased during the past 10 years. Its detection is frequently difficult, because they do not always show a minimum inhibitory concentration (MIC) value for carbapenems in the resistance range. Both broth microdilution and agar dilution methods are more sensitive than disk diffusion method, Etest and automated systems. Studies on antimicrobial treatment are based on a limited number of patients; therefore, the optimal treatment is not well established. Combination therapy with two active drugs appears to be more effective than monotherapy. Combination of a carbapenem with another active agent--preferentially an aminoglycoside or colistin--could lower mortality provided that the MIC is ≤4 mg/l and probably ≤8 mg/l, and is administered in a higher-dose/prolonged-infusion regimen. An aggressive infection control and prevention strategy is recommended, including reinforcement of hand hygiene, using contact precautions and early detection of CPE through use of targeted surveillance.