Neisseria gonorrhoeae culture growth rates from asymptomatic individuals with a positive nucleic acid amplification test.

Gonorrhoea infections are frequently diagnosed at extragenital locations in asymptomatic individuals and are historically related to poor recovery in culture, which hinders antimicrobial susceptibility testing. The aim of this study was to evaluate recovery rates of Neisseria gonorrhoeae by culture among asymptomatic individuals who tested positive by nucleic acid amplification tests between 2018 and 2019 in Barcelona (Spain). In total, 10 396 individuals were tested for N. gonorrhoeae on first-void urine, rectal, pharyngeal and/or vaginal swabs depending on sexual behaviour. Overall infection prevalence was 5·5% (95% confidence interval [CI] 5·0-5·9). Seven hundred and ten samples were positive corresponding to 567 individuals. The most common site of infection was the pharynx (71·3%), followed by rectum (23·1%) and genitals (4·7%) (P < 0·0001). The N. gonorrhoeae recovery rate in culture, time from positive screening to culture specimen and inoculation delay were calculated. Recovery rate was 21·7% in pharynx, 66·9% in rectum and 37·0% in genitals (25·0% vagina, 71·4% urethra) (P < 0·0001). Median culture collection time was 1 [0; 3] days, and median inoculation delay was 5·01 [4·99-7·99] h, with no impact on N. gonorrhoeae recovery, P = 0·8367 and P = 0·7670, respectively. Despite efforts towards optimizing pre-analytical conditions, the N. gonorrhoeae recovery rate in asymptomatic individuals is unacceptably low (especially for pharynx), representing a problem for monitoring antimicrobial-resistant infections.

Emergence and dissemination of three mild outbreaks of Neisseria gonorrhoeae with high-level resistance to azithromycin in Barcelona, 2016-18.

BACKGROUND: Neisseria gonorrhoeae (NG) isolates with high-level azithromycin resistance (HL-AziR) have emerged worldwide in recent decades, threatening the sustainability of current dual-antimicrobial therapy. OBJECTIVES: This study aimed to characterize the first 16 NG isolates with HL-AziR in Barcelona between 2016 and 2018. METHODS: WGS was used to identify the mechanisms of antimicrobial resistance, to establish the MLST ST, NG multiantigen sequence typing (NG-MAST) ST and NG sequence typing for antimicrobial resistance (NG-STAR) ST and to identify the clonal relatedness of the isolates with other closely related NG previously described in other countries based on a whole-genome SNP analysis approach. The sociodemographic characteristics of the patients included in the study were collected by comprehensive review of their medical records. RESULTS: Twelve out of 16 HL-AziR isolates belonged to the MLST ST7823/NG-MAST ST5309 genotype and 4 to MLST ST9363/NG-MAST ST3935. All presented the A2059G mutation in all four alleles of the 23S rRNA gene. MLST ST7823/NG-MAST ST5309 isolates were only identified in men who have sex with women and MLST ST9363/NG-MAST ST3935 were found in MSM. Phylogenomic analysis revealed the presence of three transmission clusters of three different NG strains independently associated with sexual behaviour. CONCLUSIONS: Our findings support the first appearance of three mild outbreaks of NG with HL-AziR in Spain. These results highlight the continuous capacity of NG to develop antimicrobial resistance and spread among sexual networks. The enhanced resolution of WGS provides valuable information for outbreak investigation, complementing the implementation of public health measures focused on the prevention and dissemination of MDR NG.

Rapid detection and identification of strains carrying carbapenemases directly from positive blood cultures using MALDI-TOF MS.

MALDI-TOF MS has been evaluated to detect carbapenemases activity and pathogen identification directly from positive blood cultures. 21 non-carbapenemase producers and 19 carbapenemase producers Enterobacteriaceae and Pseudomonas aeruginosa strains were included in the study. This technique is simple and detects carbapenemases in 4.5h with high sensitivity and specificity.

MALDI-TOF MS, a useful instrument for differentiating metallo-ß-lactamases in Enterobacteriaceae and Pseudomonas spp.

UNLABELLED: We have evaluated a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) method for the identification of carbapenemases and for distinguishing metallo-ß-lactamases (MBLs). A total of 49 noncarbapenemase-producing and 14 carbapenemase-producing Enterobacteriaceae and Pseudomonas aeruginosa clinical strains, previously characterized by PCR, were included in the study. With MALDI-TOF MS, the presence of carbapenemases was confirmed by the detection of ertapenem hydrolysis (lost of molecular peaks: 476·5 Da, 498·5 Da, 520·5 Da and presence of degradation products) in the mixture of the bacteria with the antibiotic, and classification was achieved by selective inhibition of carbapenemase activity (the ertapenem molecular peak was maintained) with ethylenediaminetetraacetic acid (EDTA). We obtained a good concordance among the results of PCR and MALDI-TOF MS. This method appears to be simple, fast and reliable for distinguishing in few hours different classes of carbapenemases, which can be very useful for epidemiological studies or to establish a specific antimicrobial therapy. SIGNIFICANCE AND IMPACT OF THE STUDY: MALDI-TOF mass spectrometry is increasingly present in microbiology laboratories due to its increasing use for bacterial identification. This study describes a method for detection of carbapenemase activity using MALDI-TOF, which is similar to the reference method: the detection of imipenem hydrolysis using UV spectrometry.