Drug resistance and phylogenetic grouping of bacteria isolated from visitors' hands in a secondary-care hospital

Abstract

Introduction: Dynamic movement in the hospital environment promotes the transmission of nosocomial pathogens and multidrug resistance mechanisms through the dissemination of organisms that carry genetic determinants. Healthcare workers play an important role in the spread of pathogens; however, the role of visitors in this environment is poorly understood. Objective: This study aimed to molecularly identify and examine the antibiotic resistance of the palmar microbiota of patients’ companions in a hospital waiting room. Methodology: Twenty-five palmar surface and interdigital space sample swabs were randomly collected and cultured on blood agar plates, and 19 colonies with different macro- and microscopic characteristics were isolated. The V4 and V6 hypervariable regions of the 16S rRNA gene from each isolate were amplified by PCR and sequenced. Maximum likelihood- and Bayesian inference-based phylogenetic analyses were performed to determine taxonomic relationships. Antibiotic resistance was evaluated by disk diffusion and broth microdilution. Results: Among the isolates, 52.6% were related to Bacillus, 36.8% to Staphylococcus, 5.3% to Enterococcus and 5.3% to Atlantibacter. All of the isolates exhibited ampicillin and penicillin resistance, while 94.7% also exhibited dicloxacillin resistance. Staphylococcus aureus was resistant to penicillins but sensitive to the remaining drugs. Bacteria identified as Bacillus subtilis (MLM14B99), Bacillus pumilus (MLM23B07 and MLM25B06), Staphylococcus epidermidis (MLM24S31 and MLM29S04), and Enterococcus (MLM22E08) showed resistance to at least 46.7% of the antibiotics. Conclusions: To decrease the transmission of pathogenic bacteria with an antibiotic resistance profile, re-evaluation of hand cleaning measures and their application by people who visit hospital centres is needed.