Antibiotic Resistance Patterns and Drug Resistance Index of Bacterial Pathogens Isolated from Bloodstream Infections at Teaching Hospital Karapitiya

Abstract

Background: Emergence of multidrug-resistant bacteria and increasing rates of antibiotic resistance necessitate more judicious use of antibiotics. Overuse, underuse or misuse of antibiotics may lead to antibiotic resistance. Overuse of antibiotics can be assessed by calculating the multi drug resistance index. Objectives: To determine the multidrug-resistance (MDR), extended drug resistance (XDR) and pan drug resistance (PDR) patterns among bacterial isolates of blood, and to determine the multidrug resistance index (MDRI) at Teaching Hospital Karapitiya (THK) Methods: A total of 423 antibiotic sensitivity results of blood culture isolates were extracted at Microbiology Laboratory, THK from January to June 2022. Extracted data was explored for the detection of MDR, XDR, and PDR of frequently isolated organisms. MDR was defined as acquired non-susceptibility to at least one agent in three or more antimicrobial categories, XDR was defined as isolate resistant to at least one agent in all but two or fewer antimicrobial categories and PDR was defined as isolates resistant to all agents in all antimicrobial categories. MDRI was used to determine the usage of antibiotics. A value of MDRI=0.2 was used as the cut off to denote high-level use of antibiotics. Results: Of all blood culture isolates, Gram-negatives (81.3%) were higher than Gram-positives (18.7%). Escherichia coli (25.1%) and Staphylococcus aureus (22.2%) were the predominant Gram-negative and Gram-positive pathogens, respectively. Majority were multidrug-resistant bacteria (57.6%). Considering all MDR Gram-negatives, Klebsiella spp. (72.7%) was the predominant isolate followed by Acinetobacter spp. (68.2%) and E. coli (66.0%). Of all MDR Gram-positives, S. aureus was the commonest (47.9%). A total of 68.6% isolates had a MDRI of >0.2. Conclusion/s: The majority of blood culture isolates were multidrug resistant and showed high MDRI indicating the necessity for immediate and effective measures to reduce misuse of antibiotics, thereby combating antimicrobial resistance. Keywords: Antibiotic resistance patterns, Extended drug resistance, Multidrug-resistance,