Manu Chaudhary

A Novel Approach to Combat Acquired Multiple Resistance in Escherichia coli by using EDTA as Efflux Pump Inhibitor

Escherichia coli is one of the leading pathogen responsible for severe ICU infections and have evolved a variety of strategies to resist antibiotics. A single resistance mechanism may diminish susceptibility to several therapeutic drugs allowing the survival of bacteria in their niches. Among the various resistance mechanisms, antibiotic removal from the bacterial cells by efflux pumps are most common. There are a number of reports indicating antibiotic resistance because of efflux pump in bacteria is increasing significantly. Therefore, antibiotic efflux pumps are thought of as attractive therapeutic targets, where their inhibition can restore antibiotic activity.

Efficacy and Safety Evaluation of Fixed Dose Combination of Cefepime and Amikacin in Comparison with Cefepime Alone in Treatment of Nosocomial Pneumonia Patients

Nosocomial pneumonia is the most frequent and leading cause of morbidity and mortality. Pseudomonas aeruginosa, the most frequent causative agent, is intrinsically resistant to most antibiotics. The study was aimed at comparing the efficacy and safety of fixed dose combination (FDC) of Cefepime and Amakacin with that of Cefepime alone in treatment of patients suffering from nosocomial pneumonia. Patients suffering from nosocomial pneumonia participated in an open-labeled, two-arm, randomized, comparative, multicentric trial. One group (n=100) of patients were treated with intravenous injection of Cefepime and Amakacin FDC 2.5g b.i.d and other group (n=100) were treated with intravenous injection of Cefepime alone 2.0g b.i.d, for 7-10 days. Outcome of therapy was evaluated on the basis of clinical and bacteriological evaluation. Clinical and bacteriological successful outcomes were significantly higher in the patients treated with Cefepime and Amakacin FDC than Cefepime alone treated patients. Analysis of patients infected with Pseudomonas aeruginosa amongst the two treatment arms indicated that clinical and bacteriological success is significantly higher in Cefepime and Amakacin FDC treated patients than Cefepime alone treated group. No major adverse events with observed in both the treatment arms. In conclusion, fixed dose combination of Cefepime and Amakacin was more effective in the treatment of nosocomial pneumonia than Cefepime alone.

Protective role of ceftriaxone plus sulbactam with VRP1034 on oxidative stress, hematological and enzymatic parameters in cadmium toxicity induced rat model

ABSTRACT We investigated the protective role of ceftriaxone plus sulbactam with VRP1034 (Elores) on hematological, lipid peroxidation, antioxidant enzymatic activities and Cd levels in the blood and tissues of cadmium exposed rats. Twenty-four male rats were divided into three groups of eight rats each. The control group received distilled water whereas group II received CdCl2 (1.5 mg/4 ml/body weight) through gastric gavage for 21 days. Group III received CdCl2 and was treated with ceftriaxone plus sulbactam with VRP1034 for 21 days. The hematological, biochemical, lipid per-oxidation levels and enzymatic parameters were measured in plasma and tissues (brain, liver and kidney) of all groups. The Cd, Zn and Fe levels were measured in blood and tissues of all groups. Our findings showed significantly decreased cadmium (p<0.001), malonaldialdehyde (p<0.001) and myloperoxidase (MPO) levels along with significantly increased hemoglobin (p<0.01), RBC (p<0.05), hematocrit (p<0.05) levels and all antioxidant enzymatic activities (SOD, CAT, GR, GPx) in plasma and tissues of ceftriaxone plus sulbactam with VRP1034 treated group as compared to cadmium exposed group. Delta aminolevulinate dehydratase (δ-ALAD) activity was significantly (p<0.001) increased in the blood of ceftriaxone plus sulbactam with VRP1034 treated group as compared with cadmium exposed group. The levels of hepatic and renal parameters were significantly (p<0.001) decreased in ceftriaxone plus sulbactam with VRP1034 treated group as compared to cadmium exposed group. These findings indicate that ceftriaxone plus sulbactam with VRP1034 acts as a potent free radical scavenger and exhibits metal chelating properties that reduce free radical mediated tissue injury and prevent dysfunction of hepatic and renal organs during metal intoxication.

Ethylenediaminetetraacetic acid: A non antibiotic adjuvant enhancing Pseudomonas aeruginosa susceptibility

Pseudomonas aeruginosa is an opportunistic bacterium which has been shown to have multi-drug resistance against fluoroquinolones, β-lactams, and aminoglycosides. In this investigation, we studied the effect of different concentrations of ethylenediaminetetraacetic acid (EDTA) on MexA-MexB-OprM efflux pump and subsequent changes in susceptibility and expression. Next, we examined, the expression of mexAB gene following treatment with half of minimum inhibitory concentration (MIC) of drugs. Our results revealed that 10 mM EDTA significantly reduced MIC of all drugs; moreover, the higher reduction (8 fold) was observed with CSE1034. MexA and MexB expression was down regulated at 2.93 and 3.21 fold, respectively with 10 mM EDTA. When the same concentration of EDTA was incorporated with drugs, the CSE1034 down regulates 5.64 and 5.94 fold expression of mexA and mexB, respectively. Moreover, meropenem treated groups exhibited 2.63 and 3.12 fold down regulation in the expression of the genes. However, treatment with piperacillin plus tazobactam, amoxicillin plus clavulanate, cefoperazone plus sulbactam and imipenem plus cilastatin did not produce changes in the expression of MexAB-OprM. Hence, CSE1034 could be one of the best choices to treat infections caused by microorganisms that overexpressed MexAB-Opr-M as compared to other drugs. Furthermore, use of EDTA disodium at appropriated concentrations can be regarded as a safe strategy to fight against the menace provided by the efflux pumps.

Role of EDTA and CSE1034 in curli formation and biofilm eradication of Klebsiella pneumoniae: a comparison with other drugs

Role of EDTA and CSE1034 in curli formation and biofilm eradication of Klebsiella pneumoniae : a comparison with other drugs

Fixed Dose Combination of Cefepime Plus Amikacin Prevent Oxidative Stress in Liver of Mus musculus Mice

Oxidative stress and free radical are causative factors for aminoglycoside induced tissue injury. The objective of present study was to evaluate effect of fixed dose combination of cefepime + amikacin on antioxidant enzymes such as superoxide dismutase (SOD), catalase along with malonaldialdehyde (MDA) levels in liver of Mus musculus mice. Our findings showed that the activities of the antioxidant enzymes such as superoxide dismutase (p<0.001, 62.2%), catalase (p<0.05, 47.5%) were significantly lowered along with increase in the MDA levels (66.0%) after the single treatment of amikacin as compared to control group. A significant improvement in the activities of superoxide dismutase and catalase along with decrease in MDA levels were observed in fixed dose combination of cefepime plus amikacin treated groups as compared to amikacin alone treated group. These findings suggest that the fixed dose combination therapy of cefepime + amikacin (Potentox) show significant free radical scavenging property which may contribute to decrease in aminoglycoside induced liver injury.

Role of CSE1034 in Escherichia coli Biofilm Destruction

Present study was conducted to assess the effect of ethylenediamine tetraacetic acid (EDTA); a non antibiotic adjuvant, and CSE1034, a novel antibiotic adjuvant entity in biofilm destruction of Escherichia coli, and comparing the efficacy with other drugs. We first determined the susceptibility of six antimicrobial agents against planktonic cultures, as well as sessile cells of E. coli clinical isolates, using the Clinical and Laboratory Standards Institute (CLSI) method. Subsequently, effects of EDTA alone, and drugs on bacterial curli production, adhesion, and in-vitro biofilm destruction were studied. The percentage of biofilm persistence was determined with spectrophotometry. The structural damage of biofilms was studied by scanning electron microscope. It was found that, among the drugs used, CSE1034 was the most effective against all of the E. coli clinical isolates, with MIC and MBEC values ranging from 32-64 μg/ml and 256-512 μg/ml, respectively. Exposure of clinical isolates with EDTA alone caused inhibitions of curli formation and bacterial adhesion at 4 to 5 mM. Further, EDTA treatment of preformed biofilm caused complete biofilm destruction at 8-10 mM. Interestingly, CSE1034 due to presence of 10 mM EDTA led to enhanced antibacterial, as well as biofilm destruction activities. Results of spectrophotometric analysis and scanning electron microscopy revealed that approximately 92% biofilms were eradicated by the CSE1034, and not by comparator drugs. The results indicate that the CSE1034 appears to be most effective drug of choice for the treatment of infections caused by E. coli.

Evaluation of Efficacy and Safety of Fixed Dose Combination of Ceftazidime-Tobramycin in Comparison with Ceftazidime in Lower Respiratory Tract Infections

Lower respiratory tract infections are major cause of morbidity and mortality. Objectives were to evaluate efficacy and safety of fixed dose combination (FDC) of Ceftazidime and Tobramycin in comparison with Ceftazidime alone in patients with lower respiratory tract infections. Patients (n=240) were randomly distributed in two arms: one arm was treated with Ceftazidime(1g)-Tobramycin(120mg) and other arm was treated with Ceftazidime (1g) alone. Patients were clinically, radiologically and bacteriologically evaluated. Clinically successful outcome was seen in 88.4% of the patients in Ceftazidime-Tobramycin treated group as compared to 61.2% in Ceftazidime alone treated group. In Ceftazidime-Tobramycin treated group, majority of pathogen isolated were H.inflenzae (35%), P. aeruginosa (24.16%), K. pneumoniae (16.66%) and M. catarrhalis (24.16%), whereas in Ceftazidime alone treated group majority of pathogen isolated were H.inflenzae (33.33%), P. aeruginosa (20%), K. pneumoniae (18.33%) and M. catarrhalis (28.33%). In Ceftazidime-Tobramycin treated group (98%), a significantly higher bacterial eradication was observed than Ceftazidime alone treated group (79%). Radiological improvement was also superior in Ceftazidime-Tobramycin treated group. No major adverse events were observed. Results showed that fixed dose combination of Ceftazidime Tobramycin is superior than Ceftazidime alone in the treatment of lower respiratory tract infections.

Prevalence, Genotyping of Escherichia coli and Pseudomonas aeruginosaClinical Isolates for Oxacillinase Resistance and Mapping SusceptibilityBehaviour

In the present study, multi-drug resistant isolates of Escherichia coli and Pseudomonas aeruginosa were obtained from different clinical specimens and were subjected to molecular typing to detect the genes encoding oxacillinases in these isolates. Subsequently, antibacterial activity of drugs was tested against selected clinical isolates. Two hundred ninety six isolates including 98 of E. coli and 148 of P. aeruginosa were collected from clinical specimens of different centers across India. Out of 246, 123 isolates showed weak synergy for ceftazidime or cefepime and imipenem or clavulanate and were considered as oxacillinase producers. Polymerase chain reaction (PCR) was performed to identify the variants of oxacillinases genes. Our results show a great diversity of occurance of oxacillinase (OXA) genes among clinical isolates. OXA-48 and OXA-10 was more prevalent in both E. coli (32.6% OXA-48; 16.3% OXA-10) and P. aeruginosa (OXA-48 32.4%; 27.0%) as evident by PCR. The incidence of other OXA genes in E. coli and P. aeruginosa varied from 4.0 to 12.1%. Of the tested drugs, cefepime plus sulbactam was found to be the most efficacious antibacterial agents with 86.5 to 87.8% susceptibility. Cefepime plus tazobactam was second most active antibacterial agent with 72.2 to 73.5% susceptibility. Surprisingly, imipenem plus cilastatin showed susceptibility to less than 35% isolates. From the above results, it is evident that cefepime plus sulbactam has enhanced in vitro antibacterial activity compared to cefepime and imipenem plus cilastatin and tazobactam combination in oxacillinases. One significant finding of this study was that cefepime was found to be effective only against the isolates caring OXA-1 and OXA-2 but found to be resistant to OXA-10, OXA-23, OXA-24, OXA-48, OXA-51 and OXA-58 genes; whereas cefepime in combination with sulbactam was found to be the most effective against all of these OXA genes in comparison to tazobactam combination.

Molecular characterization and in vitro susceptibilities of β-lactamase producing Escherichia coli, Klebsiella species, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus to CSE1034 and other β-lactams.

OBJECTIVE To study the prevalence of extended-spectrum β-lactamases (ESBLs) among 663 clinical isolates obtained from various parts of India and to study the occurrence of different variants of ESBLs among these isolates. METHODS Phenotypic characterization and susceptibility studies were performed according to the methods described in Clinical and Laboratory Standards Institute guidelines. The occurrence of ESBL variants was analyzed with PCR using the previously reported primers. RESULTS Among the six hundred sixty three isolates, the identified isolates were Acinetobacter baumannii (72), Escherichia coli (218), Klebsiella pneumoniae (30), Klebsiella oxytoca (63), Pseudomonas aeruginosa (264) and Staphylococcus aureus (16). PCR results revealed that approximately 89.0% of Pseudomonas aeruginosa isolates were positive for ESBL followed by Escherichia coli (85.3%), Klebsiella pneumoniae (76.6%), Klebsiella oxytoca (73.0%), Acinetobacter baumannii (72.2%) and Staphylococcus aureus (31.2%). The overall prevalence of ESBL was 82.5%. The presence of TEM type ESBLs were the predominant (in 186 isolates), followed by SHV (138), OXA (92), CTX-M (65), AmpC (33), KPC (28) and blaZ (5). Of the drugs involved in the study, CSE1034 was found to be the most efficacious against all of ESBL positive clinical isolates showing susceptibility approximately 95.7% with minimal inhibitory concentration values between 0.125 and 8.000 μg/mL for all strains tested. The susceptibilities of penems (meropenem and imipenem and cilastatin) ranged between 83% and 93% for all the isolates. The susceptibilities of other drugs like piperacillin and tazobactam, amoxicillin and clavulanic acid, cefoperazone and sulbactam were <45% for all the isolates. CONCLUSIONS Results of the present study indicated that majority of the isolates was susceptible to CSE1034 and it could be a potent antibacterial agent for the treatment of severe bacterial infections caused by such organisms.