Blood stream infections caused by non-fermenting gram negative bacilli, clinical correlation, MIC for colistin, gene detection

Abstract

To study the risk factors and outcome of blood stream infection caused by non-fermenting gram negative bacilli (NFGNB) and their pattern of antibiotic susceptibility and genes. We included sepsis cases with blood culture positive for NFGNB. MIC for colistin was determined by broth microdilution method. Multiplex PCR was used to detect BlaIMP, BlaVIM, BlaKPC, BlaNDM-1 genes in cephalosporin and carbapenems resistant Acinetobacter spp. isolates. Out of 4,664 cases of sepsis, 50 (1.07%) were positive for NFGNB. Acinetobacter spp. 29 (58%) was the predominant isolate, of which 16 (55.17%) isolates were resistant to cephalosporins and carbapenems. We detected BlaKPC and BlaNDM-1 genes in two of these isolates. We did not detect BlaIMP, BlaVIM, BlaKPC and BlaNDM-1 genes in any other NFGNB isolates. Majority of the strains of Pseudomonas spp. showed sensitivity to all the antibiotics tested. NFGNB sepsis patients with respiratory illness correlated well with fatal outcome (p <0.05; OR 21). More numbers of Acinetobacter spp. sepsis cases had fatal outcome (p <0.05; OR 12.83). NFGNB sepsis patients with respiratory illness and those which yielded Acinetobacter spp. correlated positively with fatal outcome. We detected BlaKPC and BlaNDM-1 genes in two strains of drug resistant Acinetobacter spp.