MALDI-TOF MS for Rapid Analysis of Bacterial Pathogens Causing Urinary Tract Infections in the Riyadh Region

Abstract

The successful treatment of bacterial disease is relied on selecting a suitable drug based on the type of bacteria and antimicrobial susceptibility testing. The study’s objective was to identify bacterial isolates from urine samples of patients from the community, followed by antimicrobial susceptibility testing of the isolated bacteria. A total of seventy urine samples were received in the clinical microbiology laboratory; out of which 18 culture-positive cultures and by direct identification using MALDI-TOF MS (Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry) were identified. Of 18 identified bacteria, 17 (94%) were pathogenic. The culture demonstrated that the major species detected in urine samples were Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, and Aeromonas caviae. E. coli (72.2%) was the most common bacterium retrieved from urine samples followed by K. pneumoniae (16.6%). Interestingly, all the isolates, except Enterococcus faecalis, were resistant to erythromycin. The isolates 8 of 13 (61.5%) were resistant to both of the cotrimoxazole and tetracycline. We performed MLST (Multi-locus Sequence Typing) typing of 13 E. coli isolates to study their genetic relatedness and diversity. MLST typing of E. coli showed a total of nine different STs (Sequence Types), which showed the diversity among them. ST 129 was the most common ST found in three E. coli isolates. In our study, two isolates with ST 1126 and ST 1432 represented the global clonal complex 155. MALDI-TOF MS provided dependable results for identifying the bacteria up to species level from urine samples by indirect culture methods. Such local surveillances are highly recommended for empirical therapy awareness and determining isolates’ level of resistance.

Molecular Characterization of Microbial Quality of Ready-to-eat Salads using Multi-locus Sequence Typing

“…In a recent study, authors observed a considerable diversity amongst various isolates of E. coli. 34 E. coli isolates in this study were found scattered, which showed an evolutionary divergence. Two islolates, S-26 and S-31 with ST 1309 were found related with the standard ETEC (Enterotoxigenic E. coli) strains (Figure 1 & 2).…”

Application of the MALTI-TOF MS Method for Identification of Vibrio spp. in Aquaculture

“…In the following years, open access protein mass spectrum libraries were created to facilitate microbial (virus, bacteria, fungi and yeast) characterization for clinical studies (Böhme et al, 2012). MALDI-TOF was first used in clinical microbiology (Seng et al, 2010;Erler et al, 2015;Patel, 2015;Anwer et al, 2022), followed by veterinary, soil, plant, food and water microbiology (Popović et al, 2017;Chun et al, 2022) and more recently for the aquatic pathogens (Jansson et al, 2020;Piamsomboon et al, 2020).…”

Molecular typing methods &amp; resistance mechanisms of MDR <i>Klebsiella pneumoniae</i>

“…Using MALDI-TOF MS, rapid identification and clustering of K. pneumoniae isolates were performed from different restaurant sites in the Al-Qassim region of Saudi Arabia [61] . MALDI-TOF MS has also been used for the quick identification and typing of many other bacterial species [62] .…”