Microbial resistance to antimicrobials is spreading all over the world making it difficult to treat diseases effectively. This study aims to understand the mechanism of resistance towards the antimicrobials Ceftazidime, Moxifloxacin and Nalidixic acid, by using resistant Enterobacter spp. and sensitive Enterobacter spp. While there was complete inhibition of growth of sensitive Enterobacter spp. at 8 µg/ml Ceftazidime, 0.125 µg/ml of Moxifloxacin and 16 µg/ml of Nalidixic acid, resistant Enterobacter spp. even tolerated 256, 32 and 1536 µg/ml Ceftazidime, Moxifloxacin and Nalidixic acid respectively. Browthdilution method was used to determine the growth of organisms at different concentrations of antibacterial agents. Mechanism of resistance was found to be present in plasmid. Absence of Beta lactamase enzyme seems to be an important finding in this sudy. B. lactamase enzyme was checked with help of the acidometric and idometric method. Plasmid isolation and analysis was done by agarose gel electrophoresis. Successful curing of plasmid was carried out with 10% sodium dodecyl sulfate (SDS). When colonies after SDS treatment were tested, resistant strains were found which were later converted to sensitive ones. In this study, the resistant Enterobacter spp. executed resistance to three different classes of antimicrobials due to the resistance plasmid. The results obtained in this study support most of the previous study findings who contributed in this field. Therefore, it might be useful to recognize the resistance mechanism, and to determine the correct practicing of drug usage.

Antimicrobial resistance developed in several pathogens poses an increasing threat to human health across the world. No country can escape from the medical and economic impacts from this serious problem. Although the antibiotic resistance is not a new phenomenon, the current magnitude and speed with which it is developing is a cause for the global concern including in India. There are so many common diseases resulting from the microorganisms such as blood stream infections, urinary tract infections, post-operative wound infections and intra-abdominal infections. In this review the antimicrobial susceptibility or resistance of Enterobacter towards antimicrobial agents and heavy metals, viz. ceftazidime, moxifloxacin, nalidixic acid, sulfamethaxazole, and nickel and lead is discussed briefly along with other antimicrobials and heavy metals. The mechanisms behind the resistance by Enterobacter was analyzed and evaluated by many workers after using currently employed susceptibility testing methods for Enterobacter spp. There are some factors influencing mode of action of fluoroquinolones, quinolones and sulfamethaxazole. History, classification, identification, clinical features and treatment of infections and the epidemiology of antimicrobials (drugs and heavy metals) resistance by the Enterobacter spp. is included in this review. Now a day, antimicrobial resistance is common in hospitals where acquired infections can be perilous. This situation compels scientists to synthesize new antibiotics and treatment modalities. Enterobacter causes nosocomial infections. It is ubiquitous and can survive on skin and dry surfaces and replicate in contaminated fluids. Numerous outbreaks have been described. Various mechanisms have been adapted by microorganisms to resist toxicity of antimicrobials. Antimicrobial drugs may be rendered inactive or ineffective by the major ways such as barrier to antibiotic entry into the bacterial cell, prevention of the antibiotic from reaching the target, often by extrusion, alteration of the target of the drug and inactivation of the antibiotic by modification or destruction. In addition, bacteria may be able to bypass the metabolic pathway affected by a particular drug or may be able to overproduce an enzyme that is inhibited by the drug action, more than one mechanism may operate at any given time

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The present work aimed to check the efficiency of various phosphate solubilizing microorganisms and their effect on seed germination. In this study, nine different strains of fungi and bacteria were used.