MALDI-TOF mass spectrometry and identification of new bacteria species in air samples from Makkah, Saudi Arabia

Abstract

BackgroundDuring the Hajj season, respiratory symptoms are very common among pilgrims. Here, we investigated the viable bacterial population in air samples collected around the slaughterhouses used during the Hajj.Methods and resultsWe collected air samples on three days from four different sites: slaughterhouses at Al-Kakia, Al-Meaisim and Al-Sharaia, and from a waste disposal area designated for the remnants of slaughter. Samples were cultured on blood agar plates for 48 h, and bacterial isolates were identified using MALDI-TOF MS. A dendrogram using the spectra of the unidentified bacterial species was constructed, and PCR amplification and sequencing of the 16S rRNA gene was performed for one isolate per cluster. In total, 2500 colonies appeared on the nutrient agar plates, and 244 were purified for further analysis. Good identification was obtained for 202 (83%) isolates by MALDI-TOF MS. The most common genera were Bacillus (n = 94, 45%) and Staphyloccocus (n = 55, 26%). Poor identification was obtained for 42 (17%) isolates, and their spectra clustering revealed that these isolates belonged to 10 species. Four of these were considered to be new species.ConclusionsDuring the Hajj, the air was contaminated by many environmental bacterial agents, and MALDI-TOF MS was successfully adapted for their rapid identification.

Gut Microbiota Colonization and Transmission in the Burying Beetle Nicrophorus vespilloides throughout Development

“…The Bruker bacterial test standard (BTS 8255343) was measured for standardization of MALDI calibration before the specimens were processed. Spectra were compared to the reference library provided by Bruker, which identified 62.3% of the colonies to species level overall using a stringent cutoff of 1.699, below which indicated no reliable identification (in the Bruker library) (57,58). To confirm these assignments and to establish the identity of colonies whose spectra were not included in the Bruker database, all unique MS spectra (including both of those with positive hits and those not present in the Biotyper database) were subsequently analyzed using 16S rRNA sequencing.…”

Awareness and level of knowledge of Surgical Site Infection among Surgical Staff in King Abdullah Medical City in Hajj-2019: A Cross-Sectional Study

“…Every year more than 2-3 million Muslims from different countries come to Makkah for the hajj season which represent one of the largest mass gathering events worldwide. Therefore, during Hajj overcrowding, high temperature, and traveling may increase the risk of infection [7][8][9].…”

Environmental investigation of respiratory pathogens during the Hajj 2016 and 2018

“…Bacillus and Staphylococcus spp. were commonly isolated [22]. To our knowledge, only one study aiming at detecting the presence of respiratory pathogens by PCR, was conducted in the context of the Hajj and was based on air and surface samples obtained in Jeddah airport in 2013 [23].…”