Prescription pattern of antibiotics in patients with postoperative infectious complications after cardiac surgery

INTRODUCTION Postoperative infectious complications after cardiac surgery are often associated with increased morbidity, mortality, and economic burden.[1,2] The most common infectious complications include deep incisional surgical site infection (SSI) and respiratory tract infection. Others include mediastinitis, infectious myocarditis or pericarditis, endocarditis, device infections, and septicemia.[3,4] Despite the use of surgical prophylaxis, the occurrence of postoperative infections cannot be brought to zero necessitating antibiotic use.[4] The objective of the study was to describe the prescribing pattern and its economic implications in patients developing postoperative infectious complications after cardiac surgery. METHODOLOGY A prospective observational study was conducted in a high-volume cardiothoracic and vascular surgery department of a government medical college in central Kerala for a period of 18 months (from December 1 2019, to May 31, 2021) after obtaining IRB clearance (IRB NO: 111/2019). During this period, 2550 open- and closed-heart surgeries were conducted. The data from all patients developing infectious complications within 90 days of cardiac surgery were included in the study and were analyzed using SPSS for Windows, version 16.0. (SPSS Inc., Chicago, IL, USA). RESULTS One hundred and fifty-seven (6.5%) patients developed 181 postoperative infectious complications. The mean age of the participants was 55.3 ± 15.65 years, and the majority (109; 69.4%) of the participants were male. One hundred and forty (89.1%) patients developed only a single postoperative infectious complication, while 17 (10.8%) patients developed more than one. SSI (107; 59.12%) was the most common postoperative infection, followed by pneumonia (40; 22.1%) and septicemia (14; 7.74%). Other infections included upper respiratory infection, urinary tract infection, catheter-related bloodstream infections, central vein-associated bloodstream infection, cellulitis, and osteomyelitis of the ribs. For the treatment of 181 postoperative infectious complications, 336 antibiotics were prescribed. Fifty-nine (37.6%) patients received monotherapy. Beta-lactam antibiotics (160; 47.6%) were the most prescribed group, and piperacillin + tazobactam (70; 20.8%) was the most frequently prescribed antibiotic. Other frequently prescribed antibiotics were meropenem + sulbactam, ciprofloxacin, and linezolid each n = 32 (9.5%). Among the 107 patients who developed SSI, 20 different antibiotics (a total of 234) were prescribed. Fifty-eight patients were prescribed piperacillin + tazobactam, 29 ciprofloxacin, and 25 linezolid. For pneumonia as well as septicemia, meropenem alone or along with sulbactam was the most common antibiotic prescribed. Definitive treatment was initiated in 43 (27.39%) patients, while the rest 114 (72.61%) patients continued their empirical treatment. Multidrug-resistant (MDR) Klebsiella was the most frequent organism isolated along with MDR Acinetobacter, MDR Escherichia coli, methicillin-resistant Staphylococcus aureus, and pseudomonas. Based on the World Health Organization prescribing indicators, the average number of antibiotics per encounter was 2.14. The percentage of antibiotic prescribed by generic name was 39.28%, 89.17% were parenterally administered and 91.96%, antibiotics from Essential Drug List (EDL). The average antibiotics cost per encounter was Rs 7555.47 of which 98.61% cost was spent on injections. Two adverse drug reactions reported were amikacin-induced elevation of renal function test and ciprofloxacin-induced hypersensitivity reaction. DISCUSSION SSI was the most common postoperative infectious complication, which is in line with Lepelletier et al.[5] As observed by Remesh et al., beta-lactams were the most prescribed group of antibiotics; however, piperacillin–tazobactam was the drug preferred in the study as compared to cephalosporins in theirs.[6] In contrast to this study, where gram negative organisms were isolated during the culture, MDR Klebsiella being the commonest, Lepelletier et al., stated that the commonest organism isolated was Staphylococcus.[5] The average antibiotic use of 2.14 (optimum1.6-1.8) and high use of injections 89.17% (optimum 13.4%-24.1%) indirectly translates to the critical condition of the patients following cardiac surgeries. Findeisen et al. found that the mean per patient cost of antimicrobials to treat SSIs was ₹64,416 (₹30,869–₹98,009) as against the mean Rs. 7556 estimated in this study.[7] Multicentric studies with longer follow-ups would bring better insights into the pharmacoeconomic implications. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.