Anusha Rohit
Antimicrobial resistance (AMR) is a growing pandemic that is threatening the whole world and India is no exception since we also face a huge problem with AMR that is multilayered due to poverty, reduced hygiene, … lack of access to clean drinking water and good public health centers.. India being a large consumer of antibiotics, resistance among multi-drug resistant organisms (MDROs) has been reported to many groups of antibiotics including carbapenems, polymixins, cephalosporins, beta-lactam- beta-lactamase inhibitor combinations leaving very few options for treatment of MDRO’s. Further the lack of a “ One-health” policy for the country, the availability of over-the-counter (OTC) antibiotics, lack of strict quality control by some pharmaceutical companies to make antibiotics cheap has only exacerbated the problem.However, the biggest problem is with metallo-beta lactamases and resistance to carbapenems, the last resort in most Intensive Care Units (ICU’s). New Delhi metallo- beta lactamases (NDM’s) are a form of carbapenem resistance enzymes first reported in isolates from India in 2008 and have been spreading since. Other mechanisms of carbapenamase enzymes include Oxa-48, VIM, IMP and KPC. It is interesting to note that KPCs are not the most common form of carbapenem resistance in India, unlike in the west. We studied 163 clinical isolates that included 118 from infection sites and 16 from rectal swabs. The clinical samples included blood (142), endotracheal secretions (1), urine (2), sputum (1), Ascitic fluid (1), all collected between 2017 to 2020.The presence of carbapenamases was studied by phenotypic and molecular testing over one year. Blood cultures from sepsis patients growing gram negative bacilli and isolates from above samples were subjected to Gene XpertCarba (Cepheid) to look for the presence of KPC, Oxa-48, NDM, VIM and IMP. Disk diffusion and MIC’s for carbapenems were also determined simultaneously. Sixteen rectal swabs were requested for carbapenemase screening during the study period. Of the 163 isolates screened for carbapenamases that included rectal screening isolates, 76.68% did not carry any carbapenamase gene. Both Oxa-48 and NDM-1 were found in equal proportion at 7.9%. NDM-1 with Oxa-48 was seen in 5.5% cases. A small proportion of isolates carried VIM (1.22%) and a combination of NDM, OXA-48 and VIM (0.6%).Interestingly, when the rectal screening isolates were eliminated, the clinical isolates showed Oxa-48 in 8.84%, NDM in 5.44%, NDM with OXA-48 in 4.08% and VIM in 1.36% of the cases.
The results show increasing importance of OXA-48 in clinical samples in India, where NDM is considered endemic. However, the predominance of NDM in rectal swabs indicates colonization by carbapenemase producing coliforms and the need to monitor patients at the time of hospital admission. KPC’s are found in very low numbers in India. Screening of patients for gut carriage of MDRO’s is of utmost importance.
