Co-expression of 16S rRNA Methyltransferase and Carbapenemase in Multidrug Resistant Gram Negative Bacteria
JOURNAL OF CLINICAL AND DIAGNOSTIC RESEARCH
Authors: Tipparthi, Sandeep Kumar; Akula, Swathi; Rajkumar, H. R., V; Reddy, A. Ravishankar; Manderwad, Guru Prasad
Abstract
Introduction: The drug resistance caused by bacteria has complicated the fight against the infectious diseases and recovery of the patients from the diseases. Multiple mode of drug resistant mechanisms including epigenetic and enzymatic mode have been involved in the genesis of drug resistance leaving only fewer antibiotics for the treatment. Studies has shown the presence of 16S methyltransferase which is associated with carbapenem drug resistance. Early detection of different multimode of bacterial drug resistance helps in reducing the dissemination rate and treatment failures. Aim: To detect the genes related to the methylation mode of bacterial drug resistant mechanism including armA (aminoglycoside resistance methylase), rmtA, rmtB, rmtC and rmtD (rmt-RNA methyltrasferase) as well as genes OXA-48 (Oxacillinase), VIM (Verona intergron metallo-beta lactamase) and KPC (Klebsiella pneumoniae carbapenemase) in the production of carbapenemases and also to identify the co-expression of these genes in the gram negative bacterial isolates. Materials and Methods: Prospective study was conducted through application of multiplex Polymerase Chain Reaction (PCR) for detection of 16S methyltransferase genes including armA, Rmt A, rmtB, rmtC and rmt D and carbpenemase VIM, KPC and OXA-48 genes, respectively. A total of 200 multidrug resistant gram negative bacilli were evaluated for presence of these genes. The antibiotic sensitivity was evaluated using Kirby-Bauer disc diffusion method. Results: The gram negative bacteria which were isolated includes Acinetobacter spp. 20, E.coli-85, Klebsiella spp.-55 and Pseudomonas aeruginosa-40 from several specimens such as urine, endotracheal tube-secretion, wound swab, sputum, pus etc. A total of 121 (61%) of the bacterial isolates were resistant to either gentamicin or amikacin and netilimycin and 50 (25%) bacterial isolates were resistant to either imipenem or carbapenem. A total of 48 (24%) isolates were resistant to both aminoglycosides and carbapenems. The 16S methyltransferase genes including armA gene was detected in 16 isolates, rmtB in 15 isolates, rmtC in 10 isolates and rmtD detected in 13 isolates The carbapenem genes detected including VIM in 20 isolates, OXA-48 in 25 isolates and KPC was detected in 13 bacterial isolates. Co-expression of both methyltransferase and carbapenemase were detected in nine isolates. Conclusion: The presence of multiple mode of bacterial drug resistance mechanisms including epigenetic and enzymatic modes have been found to be associated with resistance to different classes of antibiotics. The application of multiplex PCR helps in detection of multiple genes involved in bacterial drug resistance and helps in prevention of rapid spread of bacterial drug resistance and prevention of overuse of antibiotics.
Emergence and Persistence over Time of Carbapenemase-ProducingEnterobacterIsolates in a Spanish University Hospital in Madrid, Spain (2005-2018)
MICROBIAL DRUG RESISTANCE
Authors: Mateos, Miriam; Hernandez-Garcia, Marta; Del Campo, Rosa; Martinez-Garcia, Laura; Gijon, Desiree; Isabel Morosini, Maria; Ruiz-Garbajosa, Patricia; Canton, Rafael
Abstract
Carbapenemase production is constantly increasing among differentEnterobacteralesspecies. We analyzed the microbiological characteristics and population structure of all carbapenemase-producingEnterobacterspp. (CP-Ent) isolates recovered at the Ramon y Cajal Hospital between 2005 and 2018. Overall, 178 CP-Ent isolates (60.7% colonization, 39.3% clinical) were recovered from 165 hospitalized patients (165/176, 93.7%; medical [102/165], surgical [34/165], and intensive care unit [29/165] areas), emergency unit (4/176, 2.3%), and ambulatory patients (7/176, 4.0%). In addition, three CP-Ent were found in environmental sources. Clinical samples were mainly urine (37.1%). The most frequent matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-identified species wereEnterobacter cloacae(n = 85) andEnterobacter asburiae(n = 49).hsp60 gene sequencing showed a higher species diversity than MALDI-TOF: 70Enterobacter hormaechei-clustersIII,VI,VIII; 69Enterobacter roggenkampii-IV; 15Enterobacter kobei-II; 9E. asburiae-I; 3Enterobacter ludwigii-V; and1 E. cloacaesubsp.dissolvens-XII.NineKlebsiella aerogeneswere also identified. Overall, a high clonal diversity (Simpson Diversity Index >0.90) was found among CP-Ent-clusters. Environmental isolates were clonally related to clinical ones. Amikacin and tigecycline showed the highest susceptibility (>93%). VIM-1 (n = 133/181, 73.5%) and OXA-48 (n = 34/181, 18.8%) carbapenemases were predominant, followed by KPC-2 (n = 9/181, 5.0%), KPC-3 (n = 2/181, 1.1%), VIM-2 (n = 1/181, 0.6%), and two coproducers (VIM-1+KPC-2 and VIM-1+KPC-3). Extended-spectrum beta-lactamase (ESBL) coproduction (14.4%) emerged in 2012, mainly associated withbla(SHV-12)(p < 0.001),E. roggenkampii(p < 0.001), and colonization (p = 0.03). VIM-1- and OXA-48-CP-Ent fecal carriers increased in our hospital, particularly between 2011 and 2018 (p < 0.001). Moreover, KPC and OXA-48 producers emerged in 2010 and 2012, respectively. They superimposed over VIM producers, which were persistently recovered since first detection in 2005. These results depict increased complexity over time of CP-Ent.