Enzymatic Capabilities and Antibiotic Susceptibility of Bacteria Isolated from Medical Laboratory Surfaces in Sana’a, Yemen

Background: The surfaces of medical laboratories are potential reservoirs of multidrug-resistant (MDR) organisms, posing a significant biosafety risk. In Yemen, where national surveillance and laboratory biosafety data are limited, the extent of environmental contamination is unknown. This study aimed to provide the first characterization of bacterial flora, their antimicrobial resistance profiles, and virulence-associated enzyme production from isolates on laboratory surfaces in Sana’a.
Methods: In this descriptive microbiological study, 100 surface swabs were collected from ten medical laboratories. Bacterial identification was performed using standard biochemical methods. Antimicrobial susceptibility was determined by disk diffusion according to the EUCAST guidelines. The isolates were also screened for protease, lipase, and hemolysin production.
Results: Bacterial growth was detected in 94% (94/100) of the sampled surfaces, with the bioburden dominated by gram-positive bacteria (98.3%), primarily Staphylococcus and Bacillus spp.. The isolates exhibited high resistance rates, including near-universal resistance to ampicillin (100%) and high resistance to clindamycin (>86%) among staphylococci. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in 15.6% of S.aureus isolates. Many isolates, particularly Bacillus species, exhibit significant enzymatic activity.
Conclusion: Surfaces in medical laboratories in Sana’a harbor a significant bioburden of pathogenic and MDR bacteria, including MRSA, along with isolates with notable enzymatic capabilities. These baseline findings provide crucial data-driven evidence to inform local biosafety policies and highlight the urgent need to integrate environmental surveillance into Yemen’s national AMR action plan.