Molecular characterization and prevalence of Bacillus species isolated from Egyptian hospitals

Abstract

Background: Bacillus species are widely distributed in all environments including health care settings and represent one of the highly resistant organisms. Objective: This study aimed to find out the prevalence, molecular characterization of genetic diversity among studied Bacillus species in Egyptian hospitals environment and their antibiotic susceptibility profile. Methods: A total 528 swab samples were collected from different hospitals environment. Isolation and identification were performed according to conventional bacteriological methods, semi-automated and molecular characterization methods. Antimicrobial susceptibility was carried against different groups of antimicrobial agents. Results: The most isolated microorganism was Bacillus spp. (43.2%), followed by coagulase-negative Staphylococci (19.2%), Staphylococcus aureus (15.2%), Enterococus spp. (10.1%), Gram-negative rods (8.9%), and Micrococcus spp.(3.4 %). The most prevalent species, were Bacillus cereus (46.6%) followed by Bacillus subtilus (38.1%) while, Bacillus pumilus was the least (1.1%). A majority of Bacillus isolates (25.6%) were isolated in Internal medicine department followed by Emergency department (18.8%) while operating rooms showed the lowest prevalence rate (4.5%). Antimicrobial susceptibility testing revealed high resistance of Bacillus isolates to βlactams and tetracycline antibiotics. Multi-drug resistance (MDR) isolates which resistance to three or more antibiotics was (21.6%). Susceptibility reports of the 176 Bacillus isolates revealed 45 antibitypes and the most common was antibiotype 31, which included 32 isolates (18.2%), that is resistant to both penicillin and cefoxitin. Conclusions: This study revealed that, dissemination of Bacillus species in study hospital environments with high resistance to β-lactams and tetracycline antibiotics. The molecular analysis revealed the existence of genetic diversity among studied Bacillus isolates. Thus, monitoring the hospital environment is an important tool in the prevention of hospital-associated infection by Bacillus species.

Investigating the changing taxonomy and antimicrobial resistance of bacteria isolated from door handles in a new infectious disease ward pre- and post-patient admittance

“…This was to be expected given their wide distribution in the environment, particularly in soil, and association with food products (Rana et al, 2020). Similar to this study, Al-Habibi et al (2022) examined 407 environmental isolates across three hospitals, identifying 43.2% as Bacillus spp. and 19.2% as CoNS.…”