Antimicrobial Resistance with Focus on β-Lactam Resistance in Gram-Negative Bacilli

Pitout, Johann; Sanders, Christine C.; Sanders, William E.

doi:10.1016/s0002-9343(97)00044-2

Cited by 149 publications

(132 citation statements)

References 26 publications

Supporting

Mentioning

114

Contrasting

Unclassified

Order By: Relevance

“…Antibiotic resistance has become a serious problem threatening the health of human beings. [16][17][18][19][20] Of all the inorganic antimicrobial agents, silver elements and nanoparticle compounds have been the most extensively tested. Sondi and Salopek-Sondi recently demonstrated that silver (0) nanoparticles are quite effective antimicrobial agents against Escherichia coli.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents

Ghosh¹,

Patil²,

Ahire³

et al. 2012

IJN

205

View full text Add to dashboard Cite

Background Development of an environmentally benign process for the synthesis of silver nanomaterials is an important aspect of current nanotechnology research. Among the 600 species of the genus Dioscorea, Dioscorea bulbifera has profound therapeutic applications due to its unique phytochemistry. In this paper, we report on the rapid synthesis of silver nanoparticles by reduction of aqueous Ag + ions using D. bulbifera tuber extract. Methods and results Phytochemical analysis revealed that D. bulbifera tuber extract is rich in flavonoid, phenolics, reducing sugars, starch, diosgenin, ascorbic acid, and citric acid. The biosynthesis process was quite fast, and silver nanoparticles were formed within 5 hours. Ultraviolet-visible absorption spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and x-ray diffraction confirmed reduction of the Ag + ions. Varied morphology of the bioreduced silver nanoparticles included spheres, triangles, and hexagons. Optimization studies revealed that the maximum rate of synthesis could be achieved with 0.7 mM AgNO 3 solution at 50°C in 5 hours. The resulting silver nanoparticles were found to possess potent antibacterial activity against both Gram-negative and Gram-positive bacteria. Beta-lactam (piperacillin) and macrolide (eryth-romycin) antibiotics showed a 3.6-fold and 3-fold increase, respectively, in combination with silver nanoparticles selectively against multidrug-resistant Acinetobacter baumannii. Notable synergy was seen between silver nanoparticles and chloramphenicol or vancomycin against Pseudomonas aeruginosa , and was supported by a 4.9-fold and 4.2-fold increase in zone diameter, respectively. Similarly, we found a maximum 11.8-fold increase in zone diameter of streptomycin when combined with silver nanoparticles against E. coli , providing strong evidence for the synergistic action of a combination of antibiotics and silver nanoparticles. Conclusion This is the first report on the synthesis of silver nanoparticles using D. bulbifera tuber extract followed by an estimation of its synergistic potential for enhancement of the antibacterial activity of broad spectrum antimicrobial agents.

show abstract

Section: Introductionmentioning

confidence: 99%

Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents

Ghosh¹,

Patil²,

Ahire³

et al. 2012

IJN

205

View full text Add to dashboard Cite

show abstract

“…Extended-spectrum b-lactamases (ESBLs) are enzymes that confer resistance to penicillins, narrowand extended-spectrum cephalosporins, monobactams and related oxyimino-b-lactams (ceftazidime, cefotaxime) and have been shown to be inactive against cephamycins and carbapenems (Bradford, 2001;Bradford et al, 1994;Bush et al, 1995;Pitout and Sanders, 1997). Clavulanate, tazobactam and other blacamase inhibitors are generally effective against ESBLs although some inhibitor resistant variants have been described (Bradford, 2001;Bradford et al, 1994;Bush et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Extended spectrum β-lactamase producing Enterobacteriaceae in Lebanese ICU patients: Epidemiology and patterns of resistance

Daoud

Moubareck²,

Hakime

et al. 2006

J. Gen. Appl. Microbiol.

View full text Add to dashboard Cite

Our study aims to investigate and describe the epidemiology of the intestinal carriage of ESBL-PS in intensive care units of five Lebanese hospitals and to analyze the potential risk factors for the acquisition of these strains. At the same time, we intend to determine the patterns of susceptibility of these strains, exploring therefore the availability of alternative treatment. One thousand, four hundred forty-two fecal samples were collected between January 1, 2003 and March 31, 2003 from 378 patients admitted to the ICUs of five Lebanese tertiary care general hospitals located in different areas of Lebanon. ESBL production was detected by the double disk synergy test and antibiotic susceptibility of ESBL-producing strains as well as minimum inhibitory concentrations were determined. A paired case-control study was undertaken to identify risk factors for carriage of ESBL-PS. One hundred eighteen strains isolated from 72 subjects were identified as ESBL producers, including 95 (80.5%) E. coli, 16 (13.6%) Klebsiella pneumoniae, and 7 (5.6%) Enterobacter cloacae. A higher rate of multiple ESBL-PS carriage was described among these acquisition cases (21 double carriages and 3 triple carriages of ESBL-PS compared to only 1 double carriage of ESBL-PS at admission). In general, similar trends of susceptibility were observed in the different hospitals. As expected, the lowest MIC was observed with imipenem for all E. coli, Klebsiella, and Enterobacter isolates. Ciprofloxacin, followed by trimethoprim-sulfamethoxazole seem to be associated with the lowest susceptibility. In vitro susceptibility to cefoxitin for all isolates was 74.6%; more resistance was associated to ceftazidime (90.7%) than to cefotaxime (69.7%). Our data agree with other national and international reports showing the increase in ESBL-PS carriage in ICU patients. They demonstrate the endemic character of this carriage in Lebanese hospitals and the important risk factors including immunosuppression and evidence of ESBL infection. The highly resistant profile of ESBL-PS to antimicrobial agents available for treatment reflects the severity of this issue. The significance of this study resides in the direct correlation between our results and the nationwide increase in multi-drug resistant bacteria and the continuous change in bacterial resistance epidemiology. Our data may have an important impact on infection control policies in hospitals and on treatment of infectious diseases.

show abstract

“…ESBL producers have most commonly been documented among Klebsiella pneumoniae and E. coli strains and less commonly among other members of the family Enterobacteriaceae, such as Serratia species (9). Putative ESBLproducing bacteria have been detected in India (6), but only ESBLs CTX-M-15 and SHV-5 have been characterized (5,10).…”

Section: Case Reportmentioning

confidence: 99%

Infection with an Extended-Spectrum β-Lactamase-Producing Strain of Serratia marcescens following Tongue Reconstruction

Dhawan¹,

Bonnet

Shukla

et al. 2003

J Clin Microbiol

View full text Add to dashboard Cite

We report a case of postsurgical wound infection of polymicrobial etiology caused by Serratia marcescens and Pseudomonas aeruginosa following the use of a radial forearm free flap for oncological tongue reconstruction. S. marcescens was a producer of SHV-12 extended-spectrum ␤-lactamase (ESBL). This is the first report from India of this ESBL. S. marcescens and P. aeruginosa were resistant to the empirical perioperative antibiotics administered. Delay in the recognition of the type of infection and in the institution of appropriate therapy resulted in total loss of the free flap. CASE REPORTA 39-year-old man was admitted to the surgical oncology ward of the All India Institute of Medical Sciences (New Delhi, India) with a history of a nonhealing ulcer of 1-year duration on the left side of the tongue. An initial examination revealed a 0.5-by 1-cm indurate area on the left ventrolateral surface of the tongue. A biopsy was performed which showed a welldifferentiated squamous cell carcinoma of the left lateral border of the tongue. The tumor was classified as stages T1, N1, and M0.The patient underwent operative treatment consisting of left hemiglossectomy and unilateral supraomohyoid neck dissection. This was followed by reconstruction of the tongue with a radial forearm free flap. An initial regimen of metronidazole, amoxicillin, and clavulanic acid was started postoperatively.Ten days later, there were signs of collection of pus at the postoperative wound site. The pus was drained and sent for bacterial culture. Consecutive cultures obtained from the wound yielded growth of Serratia marcescens and Pseudomonas aeruginosa. S. marcescens is an opportunistic gram-negative bacterium that is associated with sporadic urinary tract infections and pneumonia in patients in intensive care units, although outbreaks can occur (1).Antibiotic susceptibility profiles were done by using a standard disk diffusion method recommended by the NCCLS (7). P. aeruginosa was susceptible to ciprofloxacin, ceftazidime, cefpirome, piperacillin-tazobactam, and cefoperazone-sulbactam. It was resistant to amoxicillin-clavulanic acid, piperacillin, cefotaxime, and amikacin. S. marcescens exhibited resistance to piperacillin, cefotaxime, ceftazidime, ceftriaxone, cefoperazone, cefpirome, amikacin, netilmicin, ciprofloxacin, and amoxicillin-clavulanic acid. It was sensitive to piperacillin-tazobactam and cefoperazone-sulbactam. The strain tested positive, by the method described by the NCCLS (7), for the production of extended-spectrum ␤-lactamase (ESBL).Isoelectric focusing and gene sequencing characterized the ESBL. Isoelectric focusing was performed with polyacrylamide gels containing Ampholine with a pH range of 3.5 to 10 as previously described (2). ␤-lactamases of known isoelectric points (pIs), TEM-1 (pI 5.4), TEM-2 (pI 5.6), TEM-24 (pI 6.5), SHV-5 (pI 8.2), and CTX-M-1 (pI 8.4), were used as standards. Isoelectric focusing showed that the ESBL focused at a pI of 8.4, suggesting that the ESBL of the S. marcescens strain was an SHV-type ␤-l...

show abstract

Antimicrobial Resistance with Focus on β-Lactam Resistance in Gram-Negative Bacilli

Cited by 149 publications

References 26 publications

Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents

Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents

Extended spectrum β-lactamase producing Enterobacteriaceae in Lebanese ICU patients: Epidemiology and patterns of resistance

Infection with an Extended-Spectrum β-Lactamase-Producing Strain of Serratia marcescens following Tongue Reconstruction

Contact Info

Product

Resources

About