PREVALENCE OF GRAM POSITIVE AND GRAM-NEGATIVE BACTERIA ISOLATED FROM SMARTPHONES OF UNIVERSITY STUDENTS

Abstract

Background: Smartphones have become indispensable personal devices among university students, yet their role as potential reservoirs and vectors for bacterial pathogens remains an emerging public health concern. Frequent handling, prolonged use, and infrequent disinfection create favorable conditions for microbial colonization. This study aimed to determine the prevalence of Gram-positive and Gram-negative bacteria isolated from smartphones of university students and to identify the bacterial species present on these devices. Methods: A cross-sectional study was conducted among 200 university students selected through convenient sampling. Sterile cotton swabs moistened with normal saline were used to sample frequently touched areas of smartphones, including screens, back surfaces, and edges. Samples were cultured on Blood Agar and MacConkey Agar, followed by Gram staining and biochemical testing (catalase, coagulase, indole, citrate utilization, and Voges-Proskauer tests) for bacterial identification. Data were analyzed using descriptive statistics, with frequencies and percentages calculated. Results: Bacterial growth was observed in 176 (88%) of the 200 smartphone samples, while 24 (12%) showed no growth. Gram-positive bacteria predominated, accounting for 163 (92.6%) of the 176 isolates, whereas Gram-negative bacteria constituted 13 (7.4%). Species-wise distribution revealed Staphylococcus epidermidis as the most frequently isolated organism (119; 59.5%), followed by Staphylococcus aureus (36; 18.0%), Klebsiella pneumoniae (11; 5.5%), Bacillus spp. (8; 4.0%), and Escherichia coli (2; 1.0%). After excluding S. epidermidis, S. aureus remained the dominant Gram-positive isolate (81.8%), while K. pneumoniae was the most prevalent Gram-negative organism (84.6%). Conclusion: Smartphones of university students are significantly contaminated with both commensal and potentially pathogenic bacteria. The predominance of Gram-positive organisms, particularly Staphylococcus species, reflects contamination from normal skin flora, while the presence of Gram-negative bacteria such as K. pneumoniae and E. coli suggests environmental and fecal contamination due to inadequate hand hygiene. These findings highlight the potential role of smartphones in the transmission of bacterial infections within university settings. Implementing awareness programs on hand hygiene and regular smartphone disinfection is strongly recommended to reduce microbial contamination and associated health risks.