Lipase and Protease Production Ability of Multi-drug Resistant Bacteria
Worsens the Outcomes of Wound Infections
Authors: Rahman Attaur , Sardar Saiqa , Niaz Zeeshan , Khan Asif , Sheheryar Sheheryar , Alrefaei Abdulwahed Fahad , Hamayun Muhammad , Ali Sajid 
Published: April 2024

Background:
Surgical site infections are one of the major clinical problems in surgical departments
that cost hundreds of millions of dollars to healthcare systems around the world.

Aim:
The study aimed to address the pressing issue of surgical site infections, which pose significant clinical
and financial burdens on healthcare systems globally. Recognizing the substantial costs incurred due to these
infections, the research has focused on understanding the role of lipase and protease production by multi-drug
resistant bacteria isolated from surgical wounds in the development of post-surgical wound infections.

Methods:
For these purposes, 153 pus specimens were collected from patients with severe post-surgical
wound infections having prolonged hospital stays. The specimens were inoculated on appropriate culture media.
Gram staining and biochemical tests were used for the identification of bacterial growth on suitable culture
media after 24 hours of incubation. The isolated pathogens were then applied for lipase and protease, key
enzymes that could contribute to wound development, on tributyrin and skimmed milk agar, respectively. Following
the CSLI guidelines, the Kirby-Bauer disc diffusion method was used to assess antibiotic susceptibility
patterns. The results revealed that a significant proportion of the samples (127 out of 153) showed bacterial
growth of Gram-negative (n = 66) and Gram-positive (n = 61) bacteria. In total, isolated 37 subjects were declared
MDR due to their resistance to three or more than three antimicrobial agents. The most prevalent bacteria
were Staphylococcus aureus (29.13%), followed by S. epidermidis (18.89%), Klebsiella pneumoniae
(18.89%), Escherichia coli (14.96%), Pseudomonas aeruginosa (10.23%), and Proteus mirabilis (7.87%).
Moreover, a considerable number of these bacteria exhibited lipase and protease activity with 70 bacterial
strains as lipase positive on tributyrin agar, whereas 74 bacteria showed protease activity on skimmed milk
agar with P. aeruginosa as the highest lipase (69.23%) and protease (76.92%) producer, followed by S. aureus
(lipase 62.16% and protease 70.27%).

Results:
The antimicrobial resistance was evaluated among enzyme producers and non-producers and it was
found that the lipase and protease-producing bacteria revealed higher resistance to selected antibiotics than
non-producers. Notably, fosfomycin and carbapenem were identified as effective antibiotics against the isolated
bacterial strains. However, gram-positive bacteria displayed high resistance to lincomycin and clindamycin,
while gram-negative bacteria were more resistant to cefuroxime and gentamicin.

Conclusion:
In conclusion, the findings suggest that lipases and proteases produced by bacteria could contribute
to drug resistance and act as virulence factors in the development of surgical site infections. Understanding
the role of these enzymes may inform strategies for preventing and managing post-surgical wound infections
more effectively.