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Introduction Serratia marcescens is a significant hospital-acquired pathogen, and many outbreaks of S. marcescens infection have been reported in neonates. We report a sudden breakout of S. marcescens harboring the bla IMP-4 and bla VIM-2 metallo-β-lactamase (MBL) genes that occurred from March to August 2015 in the neonatal intensive care unit of Cairo University Hospital, Cairo, Egypt. Methods During the study period, 40 nonduplicate clinical isolates of S. marcescens were collected from blood culture samples. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to identify each isolate. Then, minimum inhibitory concentrations of different antibiotics were assessed by the Vitek 2 compact system. Screening of the MBL genes bla IMP, bla VIM, bla SIM-1, bla SPM-1, and bla GIM-1 as well as the carbapenemase genes KPC, NDM, OXA-48, SME-1, and SME-2 were evaluated. Pulsed field gel electrophoresis was preformed to detect the genetic relationship of the isolates. Results Analysis showed that 37.5% of the S. marcescens clinical isolates were resistant to meropenem (minimum inhibitory concentrations ≥ 2 µg/mL), and bla IMP-4 and bla VIM-2 were the most prevalent MBL genes (42.5% and 37.5%, respectively). None of the other investigated genes were observed. Pulsed field gel electrophoresis typing revealed two discrete clones; 33/40 (82.5%) were pulsotype A and 7/40 (17.5%) were pulsotype B. Conclusion Here, we report for the first time the detection of MBL-producing S. marcescens isolates, particularly IMP-4 and VIM-2 recovered from inpatients with bacteremias from the intensive care unit at Cairo University Hospital.

Bacterial-induced mineralization has been explored for protection and consolidation of degraded limestone, concrete and plaster by precipitation of calcium carbonate. It is the first time that Bacillus sphaericus was used for consolidating the nonsterilized decayed wall paintings samples by immersing them in sterile nutritional media. The B. sphaericus used in this study produced urease, which catalyzes the hydrolysis of urea (CO(NH2)2) into ammonium (NH4) and carbonate (CO3−2) leading to the precipitation of calcium carbonate. The effect of B. sphaericus on wall paintings was determined by recording the evolution of culture media chemistry and examining the treated wall paintings under a scanning electron microscope to show the structural and morphological evolution of calcium carbonate that was investigated in wall paintings models.