Indian Journal of Medical Microbiology IAMM  | About us |  Subscription |  e-Alerts  | Feedback |  Login   
  Print this page Email this page   Small font sizeDefault font sizeIncrease font size
 Home | Ahead of Print | Current Issue | Archives | Search | Instructions  
Users Online: 189 Official Publication of Indian Association of Medical Microbiologists 
  Search
 
 ~ Next article
 ~ Previous article 
 ~ Table of Contents
  
 ~  Similar in PUBMED
 ~  Search Pubmed for
 ~  Search in Google Scholar for
 ~Related articles
 ~  Article in PDF (29 KB)
 ~  Citation Manager
 ~  Access Statistics
 ~  Reader Comments
 ~  Email Alert *
 ~  Add to My List *
* Registration required (free)  

 
 ~  Abstract
 ~  Materials and Me...
 ~  Results
 ~  Discussion
 ~  Acknowledgement
 ~  References
 ~  Article Figures
 ~  Article Tables

 Article Access Statistics
    Viewed9864    
    Printed265    
    Emailed17    
    PDF Downloaded549    
    Comments [Add]    
    Cited by others 40    

Recommend this journal

 


 
ORIGINAL ARTICLE
Year : 2005  |  Volume : 23  |  Issue : 1  |  Page : 20-23
 

Cefoxitin resistance mediated by loss of a porin in clinical strains of Klebsiella pneumoniae and Escherichia coli


Department of Microbiology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai - 600 113, India

Date of Submission12-May-2004
Date of Acceptance07-Oct-2004

Correspondence Address:
S Ananthan
Department of Microbiology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai - 600 113
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0255-0857.13867

Rights and Permissions

 ~ Abstract 

PURPOSE: Porins are outer membrane protein (OMP) that form water filled channels that permit the diffusion of small hydrophilic solutes like -lactam antibiotics across the outer membrane. Two major porins that facilitate diffusion of antimicrobials have been described in Klebsiella spp. and Escherichia coli. The present study was carried out to examine the role of porins among Extended Spectrum -Lactamase (ESBL) and AmpC -Lactamase positive strains of Klebsiella spp. and E.coli. METHODS: Preparation of OMP from phenotypically characterized clinical isolates K.pneumoniae and E.coli and the separation of the proteins by sodium dodecyl sulfate - polyacrylamide gel electrophoresis were performed as per a previously described procedure. RESULTS: OMP analysis revealed that cefoxitin and ceftazidime resistance was mediated by loss of a porin Omp K35 in the isolates of K.pneumoniae and E.coli. CONCLUSIONS: Loss of porin mediated resistance mechanism against cefoxitin was observed among the multidrug resistant K.pneumoniae and E.coli.


Keywords: Outer membrane proteins, porins, cefoxitin, Klebsiella spp., E.coli


How to cite this article:
Ananthan S, Subha A. Cefoxitin resistance mediated by loss of a porin in clinical strains of Klebsiella pneumoniae and Escherichia coli. Indian J Med Microbiol 2005;23:20-3

How to cite this URL:
Ananthan S, Subha A. Cefoxitin resistance mediated by loss of a porin in clinical strains of Klebsiella pneumoniae and Escherichia coli. Indian J Med Microbiol [serial online] 2005 [cited 2019 Jan 22];23:20-3. Available from: http://www.ijmm.org/text.asp?2005/23/1/20/13867


The outer membrane of gram-negative bacteria plays a significant role in a variety of functions and is composed of a bilayer containing phospholipids, lipopolysaccharide and outer membrane proteins (OMPs). One family of OMPs the porins, are present in large amounts in the outer membrane and form water-filled channels that permit the diffusion of small hydrophilic solutes across the membrane.[1]

Two major non-specific porins, namely Omp K35 and Omp K36 have been described in K.pneumoniae. Omp K35[2] and Omp K36[3] porins were found to be the homologues of porins OmpF and OmpC from  E.coli Scientific Name Search  respectively. OmpK36 porins allow the diffusion of a variety of a wide variety of molecules, including bacterial nutrients and antimicrobials.

Since β-lactam antibiotics penetrate the outer membrane of gram-negative bacteria, resistance could also be caused by loss or deficiency of specific porins that reduce the outer membrane permeability to β-lactam antibiotic. This might be an important factor in mediating β-lactam resistance in multidrug resistant Klebsiella spp. and E.coli in the presence and absence of broad-spectrum β-lactamase production by these isolates.

The present study was conducted with an objective to examine the presence of porin mediated resistance to β-lactam antibiotics in ESBL and AmpC β-lactamase producing and non-producing strains of K.pneumoniae and E.coli recovered from children under 5 years of age, suffering from extraintestinal infections.


 ~ Materials and Methods Top


Clinical isolates

A total of 76 isolates of K.pneumoniae (14 isolates from cases of septicaemia, 46 from urinary tract infections, 16 from respiratory tract infections) and 22 isolates of E.coli (4 from septicaemia patients, 12 from urinary tract infections and 6 from respiratory tract infections) were obtained from patients between 0 and 5 years of age attending the Institute of Child Health and Hospital for Children, Chennai, during a period of four months from January-April 2002. Isolates that were obtained as a pure and predominant growth from the clinical specimens and considered significant were only considered for the present study. The organisms were identified and speciated based on colony morphology and biochemical reactions.[4]

Antimicrobial Susceptibility testing

The sensitivity of the isolates to third generation cephalosporins (3GC) viz., ceftazidime, cefotaxime, ceftriaxone each 30 g/disc and to cefoxitin (30 g) and imipenem (30 g), (Hi-Media, India) was determined by the disc diffusion method.[5] The results were interpreted as per National Committee for Clinical Laboratory Standards (NCCLS) recommendations.[6] E.coli ATCC 25922 was used for quality control.

ESBL detection by Double Disc Diffusion Synergy Test (DDST)

Isolates with resistance or with decreased susceptibility (intermediate by NCCLS criteria) to any of the 3 GC were subjected to the standard DDST.[7] Since all the isolates were found to be resistant to atleast one of the three 3GC antibiotics, they were all tested for ESBL production by DDST.

Detection of AmpC β-lactamase production by 3D extract method

Isolates that were found resistance to cefoxitin (zone diameter <18mm) were considered screen positive for AmpC β-lactamase production. The cefoxitin resistant isolates were then confirmed for AmpC activity by 3D extract method.[8] Twenty-four Klebsiella isolates and 12 E.coli isolates were found resistant to cefoxitin. Clinical isolates of K.penumoniae and E.coli which contained plasmid derivatives of MCQ-21, CMY-2 AmpC β-lactamases respectively were tested as positive controls (supplied by Dr. Patricia Bradford, Wyeth-Ayerst Pharmaceuticals, New York).

Transfer of resistance and ESBL and AmpC β lactamase production.

Transconjugation experiments were done with ESBL and AmpC producing K.penumonieae and E.coli.[9] Mating was performed with E.coli K12 J62-2 (F-rif+lac-) (provided by Dr, Mary V. Jesudason, Christian Medical College and Hospital, Vellore) as the recipient strain. Transconjugants were selected on MacConkey agar supplemented with rifampicin (2.5mg/mL) and ceftazidime (2 g/mL).

Analysis of OMPs

The OMP profile was studied for well characterized strains with the following properties: cefoxitin resistant, ESBL positive K.pneumoniae; cefoxitin sensitive K.pneumoniae; cefoxitin resistant, ESBL and AmpC negative K.pneumoniae; cefoxitin resistant, AmpC positive K.pneumoniae; cefoxitin resistant, AmpC negative K.pneumoniae and cefoxitin sensitive E.coli, AmpC positive E.coli.

Bacterial cells were lysed by sonication (Vibra cell, Sonics and Materials, Inc.). The OMPs were obtained after treatment of cell membranes recovered by ultracentrifugation with sodium laurylsarcosinate (1%; Sigma) and subsequent ultracentrifugation following the procedure by Filip et al.[10] The OMP profile was analysed by polyacrylamide gel electrophoresis (30% acrylamide/0.8% bis-acrylamide, 20% SDS). Gels were visualized by staining with Coomassie blue (Sigma).


 ~ Results Top


The ESBL phenotypic screening by double disc diffusion synergy test showed that 18 (23.6%) isolates of K.pneumoniae (3-blood, 9-urine, 6-sputum) and 6 (27.2%) isolates of E.coli (1-blood, 3-urine, 2-sputum) were ESBL producers [Table - 1].

Of the 24 Klebsiella isolates and 12 E.coli isolates, which were found to be resistant to cefoxitin, only 5 (20.8%) isolates of K.pneumoniae (1-blood, 3-sputum, 1-urine) and 2 (16.6%) isolates of E.coli (1-blood, 1-sputum) were found to be AmpC producers by 3D enzyme extract method [Table - 1].

All the ESBL and AmpC positive clinical isolates were subjected to the conjugal resistance transfer experiment, and after repeated attempts they produced transconjungants. All the ESBL positive isolates K.pneumoniae and E.coli showed transfer of ESBL production to the recipient strain. Two cefoxitin resistant, ESBL positive isolates of K.pneumoniae did not conjugally transfer ceftazidime resistance to the recipient strain, and one strain of AmpC positive E.coli, did not transfer cefoxitin resistance.

OMP profile showed the presence of 35 kDa porin protein in cefoxitin sensitive K.pneumoniae and cefoxitin sensitive E.coli [Figure - 1]. All the other isolates lacked the protein in the 35kDa region, the loss of which mediated cefoxitin resistance in these isolates. Cefoxitin resistant, AmpC positive K.pneumoniae showed the loss of the similar protein indicating that the resistance to cefoxitin was mediated by both AmpC β-lactamase production and loss of OMP.


 ~ Discussion Top


Plasmid mediated resistance to β-lactam antibiotics was observed in the present study in addition to the ESBL and AmpC β-lactamase mediated resistance. ESBLs are not active against cephamycins, and most strains expressing ESBLs are susceptible to cefoxitin and cefotetan. However, it has been reported that ESBL producing strains can become resistant to cephamycins due to the loss of an outer membrane porin protein.[12],[13],[14] The protein profile analysis carried out in the present study showed that the cefoxitin resistance in ESBL positive and ESBL negative isolates of K.pneumoniae was due to the loss of an outer membrane protein. Loss of porins in K.pneumoniae was found to augment resistance provided by ESBLs and plasmid mediated AmpC β-lactamases, to include resistance to oxyimino- -lactams and carbapenems.[17]

Ceftazidime resistance due to porin loss in an ESBL positive isolate of K.pneumoniae, was also observed in the present study [Figure - 1], lane 1). It has been indicated in a previous study that ceftazidme enters the cell through OmpK35 porin[14] and OmpK36.[15] Reduced permeability of K.pneumoniae due to porin loss was found to increase the MIC of ceftazidime by Rasheed et al.[12] In this study, the above mentioned isolate from blood specimen, showed an minimum bactericidal concentration of 203/ g/mL. Elevated levels of ceftazidime resistance resulted from a combination of increased enzyme production and minor OMP changes as observed by a previous study[16] in a clinical isolate of K.pneumoniae.

OmpK35 and OmpK36 are involved in mediating β-lactam resistance in K.pneumoniae.[1] Cefoxitin resistance in K.pneumoniae due to reduced permeability of porins to β-lactam antibiotics has been reported.[11] In other study loss porins in K.pneumoniae was found to augment resistance provided by ESBLs and plasmid mediated AmpC β-lactamases, to include resistance to oxyimino-β-lactams and carbapenems.[16]

Loss of porin mediated resistance mechanism against cefoxitin has been observed among the multidrug resistant Klebsiella spp. and E.coli. Knowledge of the resistance mechanisms in these clinical isolates will provide the people in charge of public health with data on multidrug resistant pathogens which would be helpful in making recommendations on the best use of antibiotics and to formulate therapeutic strategies to control infections. More prudent use of antibiotics and control of the spread of these resistant organisms are necessary. More extensive study related to OMP profiles to resistance patterns should be carried out to emphasize the clinical impact of porin mediated β-lactam resistance among the clinical isolates of Klebsiella spp. and E.coli, in this part of the world.


 ~ Acknowledgement Top


The authors acknowledge Dr.SK. Amsavathani, Professor and Head, Department of Microbiology, Institute of Child Health and Hospital for Children, Chennai, for providing clinical specimen. The authors thank Lady Tata Memorial Trust for financial support.

 
 ~ References Top

1.Domenech-Sanchez A, Hernandez-Alles S, Martinez-Martinez L, Benedi JC, Arberti S. Identification and Characterization of a New Porin Gene of Klebsiella pneumoniae: In Role in β-Lactam Antibiotics Resistance . J Bacteriol 199;181:2726-32.  Back to cited text no. 1    
2.Yigit H, Anderson JG, Biddle JW, Steward CD, Rasheed JK, Valera LL, McGowen JE, Tenovar FC. Carbapenem resistance in a clinical isolate of Enterobacter aerogenes is associated with decreased expression of OmpF and OmpC porin analogs. Antimicrob Agents Chemother 2002;46: 3817-22.  Back to cited text no. 2    
3.Alberti SF, Rodriguez-Zuinones F, Schirmer T, Rummel G, Thomas JM. Rosenbusch JP, Benedi VJ. A porin from Klebsiella pneumoniae: sequence homology, three dimensional structure and complement binding. Infect Immun 1995;63:903-10.  Back to cited text no. 3    
4.Koneman EW, Allen SD, Janda WM, Schreckenberger PC, Winn WC, Ed. The Enterobactericeae In: Color atlas and textbook of diagnostic microbiology. 4thed. Philadelphia: J. B. Lippincott Co. 1992:105-84.  Back to cited text no. 4    
5.Bauer AW, Kirby WM, Sherris JC, Turck M. Antibiotic susceptibility testing by a standardized single disk method. Am J Clin Pathol 1966;45:493-6.  Back to cited text no. 5  [PUBMED]  
6.National Committee for Clinical Laboratory Standards: Performance standard for antimicrobial disk susceptibility tests, 6th ed. National Committee for Clinical Laboratory Standards, Wayne, Pa.1997;NCCLS documents M2-A6 & M100-S7.  Back to cited text no. 6    
7.Vercauteren E, DescheemaekerP, Ieven M, Sanders CC, and Goossens H. Comparison of screening methods for Detection of Extended-Spectrum β-lactamases and their Prevalence among Blood isolates of Escherichia coli and Klebsiella spp. in a Belgain Hospital. J Clin Microbiol (1997) 35:2191-7.  Back to cited text no. 7    
8.Coudron PE, Moland ES, Thomson KS. Occurrence and detection of AmpC β-lactamases among Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis isolates at a Veterans Medical Center. J Clin. Microbiol 200;38:1791-96.  Back to cited text no. 8    
9.Abigail S, Mathai E, Jesudason MV, John TJ. Ceftazidime resistance among Klebsiella pneumoniae in south India. Indian J Med Res 1995;102:53-5.  Back to cited text no. 9    
10.Filip C, Fletcher G, Wulf JL, Earhat CF. Solubilization of the Cyptoplasmic Membrane of Escherichia coli by the Ionic Detergent Sodium-Lauryl Sarcosinate. J Bacteriol 1973;115:717-22.  Back to cited text no. 10    
11.Pangon B, Bizet C, Bure A, Pichon F, Philippon A, Regnier B, Gutmann L. In vivo selection of a cephamycin-resistant, porin-deficient mutant of Klebsiella pneumoniae producing a TEM-3 β-Lactamase. J Infect Dis 1989;159:1005-6.  Back to cited text no. 11    
12.Rasheed JK, Anderson JG, Yigit H, Queenan AM, Donebecg-Sanchez A, Swenson MJ, Biddle WJ, ferraro JM, Jacoby AG, Tenover CF. Characterization of the Extended Spectrum β-Lactamase Reference Strain, Klebsiella pneumoniae K6 (ATCC 700603), which produces the Novel Enzyme SHV-18. Antimicrob Agents Chemother2000;44:2382-8.  Back to cited text no. 12    
13.Vatopoulos AC, Phillippon A, Tzouvelekis LS, Komninou Z, Legakis NJ. Prevalence of a transferable SHV-5 β-lactamase in clinical isolates of Klebsiella pneumoniae and Escherichia coli in Greece. J Antimicrob Chemother 1990;26:635-48.  Back to cited text no. 13    
14.Martinez-Martinez L, Hernandez-Alberti S, Tomas J, Benedi V, Jacoby GA. In vivo selection of porin-deficient mutant of Klebsiella pneumoniae with increased resistance of cefoxitin and expanded-spectrum cephalosporins. Antimicrob Agents Chemother 1996;40:342-8.  Back to cited text no. 14    
15.Crowly B, Benedi JV, Domenech-Sanchez. Expression of SHV-2-β-Lactamase and of reduced amounts of OmpK36 porin in Klebsiella pneumoniae results in increased resistance to cephalosporins and carbaphenems. Antimicrob Agents Chemother 2002;46:3679-82.  Back to cited text no. 15    
16.Rice LB, Carias LL, Hujer AM, Bonafede M., Hutton R, Hoyen C, Bonomo RA. High-level expression of chromosomally encoded SHV-1 β-lactamase and an outer membrane protein change confer resistance to ceftazidime and piperacillin-tazaobactam in a clinical isolate of Klebsiella pneumoniae. Antimicrob Agent Chemother 2000;44:362-7.  Back to cited text no. 16    
17.Martinez-Martinez L, Pascual A, Hernandez-Alles S, Alvarez-Diaz D, Saurez AI, Tran J, Benedi VJ, Jacoby GA. Roles of β-Lactamase and porins in activities of carbapenems and cephalosporins against Klebsiella pneumoniae. Antimicrob Agents Chemother 199;43:1669-73.  Back to cited text no. 17    


Figures

[Figure - 1]

Tables

[Table - 1]

This article has been cited by
1 The antigens contributing to the serological cross-reactions of Proteus antisera with Klebsiella representatives
Agata Palusiak
Molecular Immunology. 2014;
[Pubmed] | [DOI]
2 Prevalence of Extended Spectrum ▀-lactamase-Producing Klebsiella pneumonia in Clinical Isolates
Khalid A Ali AbdelRahim,Ahmed Mohamed Ali Mohamed
Jundishapur Journal of Microbiology. 2014; 7(11)
[Pubmed] | [DOI]
3 Therapeutic challenges of ESBLS and AmpC beta-lactamase producers in a tertiary care center
Naveen Grover,A.K. Sahni,S. Bhattacharya
Medical Journal Armed Forces India. 2013; 69(1): 4
[Pubmed] | [DOI]
4 The beta lactam antibiotics as an empirical therapy in a developing country: An update on their current status and recommendations to counter the resistance against them
Thakuria, B. and Lahon, K.
Journal of Clinical and Diagnostic Research. 2013; 7(6): 1207-1214
[Pubmed]
5 Therapeutic challenges of ESBLS and Ampc beta-lactamase producers in a tertiary care center
Grover, N. and Sahni, A.K. and Bhattacharya, S.
Medical Journal Armed Forces India. 2013; 69(1): 4-10
[Pubmed]
6 Prevalence of extended spectrum beta-lactamase production among uropathogens in south Mumbai and its antibiogram pattern
Aruna, K. and Mobashshera, T.
EXCLI Journal. 2012; 11: 363-372
[Pubmed]
7 Cefoxitin is both an inhibitor of class A beta-lactamase of Xanthomonas campestris pv. campestris str. 17 and an inducer of its gene
Tsuey-Ching, Y. and Hecht, D. and Tsai, J.J.P. and Hu, R.-M.
Research in Microbiology. 2012; 163(8): 550-556
[Pubmed]
8 Occurrence of Plasmid-Mediated AmpC ╬▓-Lactamases Among Escherichia coli and Klebsiella pneumoniae Clinical Isolates in a Tertiary Care Hospital in Bangalore
Sasirekha, B. and Shivakumar, S.
Indian Journal of Microbiology. 2012; 52(2): 174-179
[Pubmed]
9 Cefoxitin as an alternative to carbapenems in a murine model of urinary tract infection due to Escherichia coli harboring CTX-M-15-type extended-spectrum ╬▓-lactamase
Lepeule, R. and Rupp├ę, E. and Le, P. and Massias, L. and Chau, F. and Nucci, A. and Lefort, A. and Fantin, B.
Antimicrobial Agents and Chemotherapy. 2012; 56(3): 1376-1381
[Pubmed]
10 Cefoxitin is both an inhibitor of class A beta-lactamase of Xanthomonas campestris pv. campestris str. 17 and an inducer of its gene
Yang Tsuey-Ching,David Hecht,Jeffrey J.P. Tsai,Rouh-Mei Hu
Research in Microbiology. 2012; 163(8): 550
[Pubmed] | [DOI]
11 Occurrence of Plasmid-Mediated AmpC ▀-Lactamases Among Escherichia coli and Klebsiella pneumoniae Clinical Isolates in a Tertiary Care Hospital in Bangalore
B. Sasirekha,Srividya Shivakumar
Indian Journal of Microbiology. 2012; 52(2): 174
[Pubmed] | [DOI]
12 Extended spectrum β-lactamase producing Enterobacteriaceae & antibiotic co-resistance
Rudresh, S.M., Nagarathnamma, T.
Indian Journal of Medical Research. 2011; 133(1): 116-118
[Pubmed]
13 Prevalence of ESBL-ProducingKlebsiella pneumoniaeIsolates in Tertiary Care Hospital
Vemula Sarojamma,Vadde Ramakrishna
ISRN Microbiology. 2011; 2011: 1
[Pubmed] | [DOI]
14 Incidence of temonera, sulphuhydryl variables and cefotaximase genes associated with ╬▓-lactamase producing escherichia coli in clinical isolates
Isaiah, I.N. and Nche, B.T. and Nwagu, I.G. and Nwagu, I.I.
North American Journal of Medical Sciences. 2011; 3(12): 557-561
[Pubmed]
15 Comparison of the boronic acid disk potentiation test and cefepime-clavulanic acid method for the detection of ESBL among AmpC-producing Enterobacteriaceae
Shoorashetty, R.M. and Nagarathnamma, T. and Prathibha, J.
Indian Journal of Medical Microbiology. 2011; 29(3): 297-301
[Pubmed]
16 Extended spectrum ╬▓-lactamase producing Enterobacteriaceae & antibiotic co-resistance
Rudresh, S.M. and Nagarathnamma, T.
Indian Journal of Medical Research. 2011; 133(1): 116-118
[Pubmed]
17 Genetic methods for detection of antibiotic resistance: Focus on extended-spectrum ╬▓-lactamases
Chroma, M. and Kolar, M.
Biomedical Papers. 2010; 154(4): 289-296
[Pubmed]
18 Sepsis in newborns
Brad, G.F. and SabăÄu, I. and Micle, I. and Boia, M. and Pop, E. and Popoiu, C. and Kundnani, N.
Timisoara Medical Journal. 2010; 60(4): 312-317
[Pubmed]
19 PER, CTX-M, TEM and SHV beta-lactamases in clinical isolates of Klebsiella pneumoniae isolated from Tehran, Iran
Nasehi, L. and Shahcheraghi, F. and Nikbin, V.S. and Nematzadeh, S.
Iranian Journal of Basic Medical Sciences. 2010; 13(3): 111-118
[Pubmed]
20 Genetic methods for detection of antibiotic resistance: Focus on extended-spectrum β-lactamases
Chroma, M., Kolar, M.
Biomedical Papers. 2010; 154(4): 289-296
[Pubmed]
21 Genetic methods for detection of antibiotic resistance: focus on extended-spectrum i?-lactamases
Magdalena Chroma,Milan Kolar
Biomedical Papers. 2010; 154(4): 289
[Pubmed] | [DOI]
22 PER, CTX-M, TEM and SHV beta-lactamases in clinical isolates of Klebsiella pneumoniae isolated from Tehran, Iran
Nasehi, L., Shahcheraghi, F., Nikbin, V.S., Nematzadeh, S.
Iranian Journal of Basic Medical Sciences. 2010; 13(3): 111-118
[Pubmed]
23 Discrepancy between Vitek 2 and the agar disk method in detecting the amoxicillinclavulanate resistance in a Klebsiella pneumoniae isolate
Savini, V., Catavitello, C., Balbinot, A., Bianco, A., Masciarelli, G., Astolfi, D., DŠAntonio, D.
Infezioni in Medicina. 2010; 18(1): 53-54
[Pubmed]
24 High Prevalence of Extended-spectrum Beta-lactamase-producing Enterobacteriaceae in Bacteremia After Transrectal Ultrasound-guided Prostate Biopsy: A Need for Changing Preventive Protocol
Horcajada, J.P., Busto, M., Grau, S., SorlÝ, L., Terradas, R., Salvadˇ, M., Lorente, J.A., (...), Knobel, H.
Urology. 2009; 74(6): 1195-1199
[Pubmed]
25 Altered membrane permeability in multidrug resistant Escherichia coli isolated from extra-intestinal infections
Arora, B., Jagdale, T.
African Journal of Biotechnology. 2009; 8(21): 5995-5999
[Pubmed]
26 High Prevalence of Extended-spectrum Beta-lactamase-producing Enterobacteriaceae in Bacteremia After Transrectal Ultrasound-guided Prostate Biopsy: A Need for Changing Preventive Protocol
Juan P. Horcajada,Marcos Busto,Santiago Grau,Luisa SorlÝ,Roser Terradas,Margarita Salvadˇ,Jose A. Lorente,Araceli Gonzßlez,Hernando Knobel
Urology. 2009; 74(6): 1195
[Pubmed] | [DOI]
27 Detection of extended-spectrum ╬▓-lactamases (ESBLs) in Escherichia coli
Shahcheraghi, F. and Nasiri, S. and Noveiri, H.
Iranian Journal of Clinical Infectious Diseases. 2009; 4(2): 65-70
[Pubmed]
28 Occurrence and detection of AmpC ╬▓ lactamases among clinical isolates of E.coli and K pneumoniae causing UTI
Ekadashi, R. and Rawat, U. and Malhotra, V.L. and Mehta, G.
Journal of Communicable Diseases. 2008; 40(1): 21-25
[Pubmed]
29 Occurrence of ESBL & Amp-C ╬▓-lactamases & susceptibility to newer antimicrobial agents in complicated UTI
Taneja, N. and Rao, P. and Arora, J. and Dogra, A.
Indian Journal of Medical Research. 2008; 127(1): 85-88
[Pubmed]
30 Detection of extended spectrum beta-lactamase from clinical isolates in Davangere
Sridhar Rao, P., Basavarajappa, K., Krishna, G.
Indian Journal of Pathology and Microbiology. 2008; 51(4): 497-499
[Pubmed]
31 Occurrence and detection of AmpC β lactamases among clinical isolates of E.coli and K pneumoniae causing UTI
Ekadashi, R., Rawat, U., Malhotra, V.L., Mehta, G.
Journal of Communicable Diseases. 2008; 40(1): 21-25
[Pubmed]
32 Occurrence of ESBL & Amp-C β-lactamases & susceptibility to newer antimicrobial agents in complicated UTI
Taneja, N., Rao, P., Arora, J., Dogra, A.
Indian Journal of Medical Research. 2008; 127(1): 85-88
[Pubmed]
33 Promethazine renders Escherichia coli susceptible to penicillin G: real-time measurement of bacterial susceptibility by fluoro-luminometry
Janne Lehtinen,Esa-Matti Lilius
International Journal of Antimicrobial Agents. 2007; 30(1): 44
[Pubmed] | [DOI]
34 Role of outer membrane proteins of Gram-negative bacteria in interaction with human organism [Rola bia┼éek b┼éony zewn╚ęjrznej w oddzia┼éywaniach bakterii Gram-ujemnych z organizmem gospodarza]
Bugla-Płoskońska, G. and Futoma-Kołoch, B. and Doroszkiewicz, W.
Postepy Mikrobiologii. 2007; 46(2): 139-152
[Pubmed]
35 Promethazine renders Escherichia coli susceptible to penicillin G: real-time measurement of bacterial susceptibility by fluoro-luminometry
Lehtinen, J., Lilius, E.-M.
International Journal of Antimicrobial Agents. 2007; 30(1): 44-51
[Pubmed]
36 Role of outer membrane proteins of Gram-negative bacteria in interaction with human organism | [Rola białek błony zewnȩjrznej w oddziaływaniach bakterii Gram-ujemnych z organizmem gospodarza]
Bugla-Płoskońska, G., Futoma-Kołoch, B., Doroszkiewicz, W.
Postepy Mikrobiologii. 2007; 46(2): 139-152
[Pubmed]
37 ampC gene expression in promoter mutants of cefoxitin-resistant Escherichia coli clinical isolates
Tracz, D.M., Boyd, D.A., Hizon, R., Bryce, E., McGeer, A., Ofner-Agostini, M., Simor, A.E., (...), Zoutman, D.
FEMS Microbiology Letters. 2007; 270(2): 265-271
[Pubmed]
38 Mechanisms of Antimicrobial Resistance in Bacteria
Tenover, F.C.
American Journal of Medicine. 2006; 119(6 Suppl 1): S3-S10
[Pubmed]
39 Mechanisms of Antimicrobial Resistance in Bacteria
Fred C. Tenover
The American Journal of Medicine. 2006; 119(6): S3
[Pubmed] | [DOI]
40 Mechanisms of antimicrobial resistance in bacteria
Fred C. Tenover
American Journal of Infection Control. 2006; 34(5): S3
[Pubmed] | [DOI]



 

Top
Print this article  Email this article
Previous article Next article

    

ę 2004 - Indian Journal of Medical Microbiology
Published by Wolters Kluwer - Medknow

Online since April 2001, new site since 1st August '04