Bacterial bloodstream infections in medical and surgical intensive care units: a study of distribution and susceptibility patterns

Aim: Blood stream infections are common in critically sick patients and the clinicians have to use antibiotics to manage. The susceptibility of the microorganisms varies widely from institution to institution, and from country to country. This study was carried out to document the distribution and antimicrobial susceptibility patterns of bloodstream bacterial infections over a six-month period in the medical and surgical intensive care units (ICUs) at NRI Academy of Medical Sciences, in the Southern Region of India. Methodology: This was a retrospective study conducted from June 2020 to December 2020. The study included all patients of either gender, aged above 18 years, admitted in the medical and surgical ICUs for whom blood specimens for culture were positive for BSI. The data for each of the ICUs was compared separately for the type and the number of isolates. The antibiotic susceptibility was assessed for both the ICUs together. The data was analysed using the Medcalc (R) software. Results: Medical and surgical intensive care units had 103 and 30 culture positive cases respectively. Among the culture positive cases, fermentive and non-fermentive gram-negative were equally isolated at 51 (38.3%) samples each and 31(23.3%) were gram-positive organisms. Altogether, Acinetobacter (20.3%) was the major isolate followed by E. coli (14.2%) and Klebsiella (13.5%). Acinetobacter was most sensitive to colistin (70.4%) followed by levofloxacin (63.0%) and tigecycline (55.6%). E. coli were sensitive to colistin and tigecycline, (100%), followed by amikacin (78.9%), meropenem (68.4%), gentamicin (63.2%). Similar sensitivity was observed for Klebsiella. Conclusion: This study highlights the predominance of gram-negative bacteria in the ICUs and the emergence of multidrug resistant organisms and higher rate of antimicrobial resistance among gram-negative and gram-positive organisms which is an alarming issue. The knowledge of the pathogens causing BSIs in the ICUs and their antibiotic sensitivity patterns can be of help to the clinicians in choosing appropriate empiric antimicrobial therapy. Appropriate empiric therapy is key for decreasing the length of hospital stay and mortality associated with severe sepsis and septic shock associated with blood stream infection in the ICUs.