Detection of Conjugative Plasmid Encoded Ampicillin and Tetracycline Resistant in Klebsiella pneumonia

Klebsiella pneumonia were isolated and identified on the basis of morphology, growth, and biochemical characteristics. All the isolates offered different resistance patterns against antibiotics including Ampicillin, Cefotaxime, Erythromycin, tetracycline and Chloramphenicol. Transformation and conjugation techniques were used for plasmid transfer studies. The conjugation experiment showed that ≈ 51kbp conjugative plasmid conferring resistance to tetracycline and ampicillins were successfully transferred to the recipient cells E. coli MM294. The rest of the plasmid borne markers was non-conjugative/nontransferable. Conjugative plasmids carry a tremendous potential to disseminate resistance markers to distant recipient cells. The protocol is reliable enough to be used for large-scale visualization of native plasmids and we have used it to visualize and isolate DNA from hundreds of multidrug resistance plasmids.


Introduction
Bacteria belonging to genus Klebsiella frequently cause human nosocomial infections.In particular, the medically most important Klebsiella species, Klebsiella pneumoniae, account for significant proportion of hospital acquired urinary tract infection, pneumonia, septicemia, and soft tissue infection (Emori & Gaynes, 1993).K. pneumoniae is frequently found in many different geographical locations, with beta-lactamase resistance becoming a growing problem (Matthew, 1979).
The wide spread use of antimicrobial agents in the treatment of infections in the tropics has led to serious problems of antimicrobial resistance.The emergence and spread of antibiotic resistance in bacteria of medical importance imposes serious constraint on the option available for treatment of many infections (Nikadio, 1998).(Li & Lim, 2000) mentioned that in the last 10 years, the extensive spread of multiple antibiotic-resistant Klebsiella pneumoniae strains, especially the extended-spectrum beta lactamase producing strains (ESBLs), has become a major threat to the ever-increasing number of immune compromised patients; the ESBLs are usually plasmid mediated (R plasmid) offer resistance to antibiotics and are transmissible from one cell to another by direct cell contact (conjugation).both a respiratory and fermentative type of metabolism.Optimal temperature is 37°C.D-Glucose and other carbohydrates are catabolized with the production of acids and gas.Oxidase negative and catalese positive Indole, methyl red, Voges-proskauer, and Simmons citrate reactions vary among species.Several species hydrolyze urea grow on KCN.H 2 S is not produced .Reduces Nitrates.Most species ferment all tested carbohydrates except dulcitol and erythritol (Holt et al., 1994).

Genetic Contents of K. pneumoniae
The genetic material in bacteria is carried on double -stranded circular DNA molecule, folded multiple times to fit inside the cell and attached to the plasma membrane.This DNA molecule is generally referred to as the bacterial genome.It contains all the information for controlling the development and metabolic activities important for bacterial survival.The typical bacterial genome is a single chromosome, about 1.100 mm, containing up to 4000 kbp of DNA, folded into a tight mass, often less than 0.2 mm in diameter, and complexed with small amounts of protein and RNA (Cano et al., 1986).Numerous bacteria contain, in addition to their genome, one or multiple copies of small self-replicating pieces of circular double stranded DNA, called plasmids.The molecular mass of the plasmid is between 1.5 -300 MD and it contains 1-30 kbp.Small plasmids contain only a few genes, while the larger one may consist hundreds of genes (up to 300 genes) (Jawetz et al., 1995).After division of the bacterial cell, all the following generations will have the same plasmid profile, belonging to a same bacterial clone.The transfer of the plasmid between cells can be accomplished by conjugation or transformation.Genetic information, required for transfer by conjugation, is supplied by the so-called tra-genes, carried on the other side, by self-transmissible plasmids.Plasmids transferred by conjugation, continue to multiply once they have entered the new host.Some of their genes can even be transferred to the chromosome as transposons leading to the acquisition of functions not normally encoded in the chromosome (Zajcek, 1994).In general, the plasmid's genetic information is not necessary for the survival of the cell.However, they can supply the bacterial cells with new features, important for their survival in new and extraordinary conditions.Depending on what kind of a function the plasmid determinates, there are different types of plasmids: F-plasmids -which contain genes for production of F-pills, Col-plasmids -determine a production of bacteriocines, Vir-plasmids -closely related with the pathogen potential of different bacteria, Ent-plasmids -with genes for exotoxine production determination.There are plasmids that often carry genetic information that makes the bacterium resistant to certain antibiotics and heavy metals, able to synthesize or break down unusual compounds, resistant to ultraviolet light or able to produce bacteriocines and toxins.For example, antibiotic resistance genes may be carried on plasmids (so called R-plasmids) and the plasmids are the structures that code for enzymes that acetylate adenylate or phosphorylate various antibiotics (Cano et al., 1986).Nowadays, nosocomial infections are an important cause of morbidity and mortality.Predominant pathogens are Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus, E. coli, K. pneumoniae and Candida spp (Haur et al., 1996).Among Gram-negative bacilli, which comprise the majority of nosocomial pathogens, K. pneumoniae, has considerably big role (Horan et al., 1988).The genus Klebsiella, as a member of the family Enterobacteriaceae, encloses two medical significant species: K. pneumoniae (with four variations-K.pneumoniae var.aerogenes, var.pneumoniae, var.rhinoscleromatis and var.ozaenae) and K. oxytoca.K. pneumoniae is a member of the normal intestinal microflora and it can be found in minority as a part of the microflora of the upper respiratory tract.It becomes pathogenic only when will reach tissues outside of its normal flora site.K. pneumoniae often colonizes the skin and mucosae of hospitalized patients in intensive care units, with risk of invasive infection and septicemia.The colonization of the host's gastrointestinal tract by multi-antibiotic resistant K. pneumoniae strains is thought to be an essential step in nosocomial K. pneumoniae infections.The most frequent sites of clinically important infections are the urinary, billiary and lower respiratory tract, but it can also play a role in septicaemia, meningitis and osteomyelitis (Seldon et al., 1971).

Antimicrobial Resistance
Antimicrobial resistance is defined as "a property of bacteria that confers the capacity to inactivate or exclude antibiotics, or a mechanism that blocks the inhibitory or killing effects of antibiotics, leading to survival despite exposure to antimicrobials" (Ingli et al., 1994.)

Plasmids
Plasmids form a vital part of the bacterial genome and can constitute up to 10% or more of the DNA in a bacterial cell.Plasmids can transfer by a variety of means including conjugation and transformation.Most bacteria are capable of becoming hosts to a large array of different plasmids commonly found in other strains, other species or even other genera.Plasmids thus represent a large genetic resource for diversity and adaptation of bacteria (Thorsted et al., 1998).
Resistance to β-lactam antibiotics is mediated by plasmid with variations of the SHV and TEM-type β-lactamase genes (Barthelemy et al., 1988).Most of these plasmid-mediated β-lactamases from Klebsiella species have been grouped as TEM or SHV-related β-lactamases (Horii et al., 1993).Furthermore, K. pneumoniae is the species in which plasmid-encoded ESBLs are commonly reported (Jacoby & Medeiros, 1991).The threat of an increase in multiple resistances to antibiotics in K. pneumoniae is shown by French et al. (1996) with hyper production of SHV-5 β-lactamase.Nevertheless, it has been reported that the majority of ESBL-producing isolates of E. coli and Klebsiella species are also resistant to gentamicin and other aminoglycosides (Jones et al., 1994).All these multiple resistance genes are usually carried on large transferable plasmids.Large plasmid profiles from K. pneumoniae associated with multiple resistances have been documented in Europe (Montgomerie et al., 1993;Reed et al., 1995;Marchese et al., 1996), United States (Wallace et al., 1995;Schiappa et al. 1996) and Asia (Wang et al., 1995).Prodinger et al. (1996) mentioned that there was R plasmid with 80 kbp responsible for conferring resistance to SHV-5 in K. pneumoniae isolates.This R plasmid transfer between species of family Enterobacteriaceae in nosocomial out break stresses the need plasmid typing, especially because SHV-5 beta-lactamase seems to regionally spread predominately via plasmid transfer.Shannan et al. (1998) showed that 70 to 160 kbp of conjugative plasmid responsible for encoding the SHV-4, TEM-15 and TEM-16 in K.pneumoniae.(Li & Lim, 2001) showed novel large plasmid (97~145 Kbp) carrying multiple β -lactamase resistance genes isolated from K. pneumoniae strain.

Plasmids and Bacterial Strain
Table 1.Plasmids and strains that used in experiment hsd R -: lack of restriction system; hsd M + : presence of modification system; hsd M -: lack of modification system; rec A -: lack of recombination system; end AI: lack of end nuclease activity; gal -: have no ability to ferment galactose; tra -: lack of tra genes; Antibiotic solutions were prepared according to (Al-zaaq, 1987;Baron & finegold, 1990).The antibiotic solution stocks sterilized by Millipore filter 0.22, and stored at 4°C.
Table 2. concentration of antibiotics that used in the culture media b.Saline EDTA The buffer was prepared by dissolving 0.15 mol of sodium chloride, 0.1 mol of EDTA in distilled water and the pH was adjusted to 8 with 1 N NaOH.Then volume of solution was adjusted to one liter with distilled water.The solution was sterilized by autoclave (Murmur, 1961).

c. Lysozyme Solution
This solution was prepared freshly by dissolving 10 mg of Lysozyme in 200 µl STET buffer (Sambrook et al., 1989).

d. SDS Solution
This solution was prepared by dissolving 50 mmol of Tris-base in 70 ml of distilled water then the pH was adjusted to 12.6 with 1.2 ml of 2N NaOH.The volume was completed to 100 ml with distilled water.The solution was sterilized by filtration and stored at 4°C (Kado & Liu, 1989).

e. TE Buffer
The buffer was prepared by dissolving 0.01 mol of Tris-base and 0.001 mol of EDTA in distilled water then the pH adjusted to 8. The volume of the solution was completed to one liter with distilled water and the solution was sterilized by autoclave (Sambrook et al., 1989).

f. STE Buffer
The buffer was prepared by dissolving 0.050 M of Tris-base, 0.005 M of EDTA and 0.050 M of NaCl in distilled water then the pH adjusted to 8. The volume of the solution was completed to one liter with distilled water and the solution was sterilized by autoclave (Sambrook et al., 1989).

g. EDTA-Sodium Acetate
The Solution was prepared by dissolving 3 mol of sodium acetate, 0.001mol of EDTA in distilled water.The pH was adjusted to 7 with acetic acid, and then the volume of the solution was completed to one liter with distilled water.The solution was sterilized by autoclave (Sambrook et al., 19819).

h. Chloroform-Isoamyl Alcohol Mixture
This solution was prepared in a ratio of 24:1 and stored in bottle at 4°C (Sambrook et al., 1989).

Antibiotic
Final concentration in culture media (µg/ml) The solution was prepared by melting the phenol at of 68°C, and then 0.1% of antioxidant 8-hydroxyquinoline was added to it, un equal volume of buffer solution of 0.5 mol Tris-HCl at pH 8 was added to the mixture and mixed well by mechanical vortex and then the solution left to set at room temperature.The upper aqueous layer was separated from the lower layer.The upper layer was discard by pasture pipette and then an equal volume of 0.1 molar Tris-HCl pH 8 was added to the phenol and this process was repeated until the pH of phenol become more than 7.8.The phenol solution was stored under thin layer of 0.1 molar Tris solution in a dark bottle at 4°C (Sambrook et al., 1989).j.Phenol: Chloroform: Isoamyl Alcohol Mixture Phenol, chloroform, isoamyl alcohol was mixed together at ratio of 25:24:1 and was stored under a layer of 0.1 molar Tris-HCl solution (pH 8) in a dark bottle at 4°C (Sambrook et al., 1989).

k. TBE Buffer
The solution was prepared by dissolving 0.089 mole of Tris-base, 0.089 mole of boric acid and 0.002 mole Na 2 -EDTA in distilled water.The pH of the solution was adjusted to 8 with 1 N NaOH and the volume of solution was completed to one liter with distilled water.The solution was sterilized by autoclave (Sambrook et al., 1989).

l. Ethedium Bromide Dye
The dye solution was prepared by dissolving 0.5 mg of Ethedium bromide in 10 ml distilled water, and the solution was stored in dark bottle at room temperature (Sambrook et al., 1981).
m. Extraction Solution: Solution I was prepared by mixing 50 mM glucose, 25 mM Tris-Cl (pH 8) and 10 mM EDTA (pH 8).The solution was prepared in batches of ~100 ml then the solution was sterilized by autoclave and stored at 4°C.
Solution II was prepared by mixing 0.2 N NaOH (freshly diluted from 10 N stocks) and 1% SDS.Solution III (3M Sodium acetate) pH 4.8: It was prepared by mixing 60 ml of 5 M potassium acetate, 11.5 ml glacial acetic acid and 28.5 ml of distilled water (Sambrook et al., 1989).

n. Normal Saline
It was prepared by dissolving 0.15 moles from sodium chloride and 0.1 mole of KH 2 PO 4 in distilled water, the pH was adjusted to 7.2 by adding 1 N NaOH.Then the volume was completed to one liter by adding distilled water, and then sterilized by autoclave.

Culture Media
A. Ready Culture Media Table 3. Ready culture media used during experiments
The following media were prepared as recommended by the manufacturing company and autoclaved.

B. Prepared Culture Media a. SOC Liquid Medium
It was prepared by dissolving 2 gm of trypton, 0.5 gm yeast extract, and 0.005 gm sodium chloride in 90 ml distilled water and then 1 ml of 0.25 M of potassium chloride was added, the pH of the solution was adjusted to 7 and the volume completed to 100 ml.Before using, 0.5 ml of 2 M magnesium chloride, and 1 ml of 0.25 molar of glucose previously been sterilized by filtration was added when the medium used as solid culture, 2% of agar would be added (Sambrook et al., 1989).

b. Luria broth
It was prepared by dissolving10 gm of trypton, 5 gm yeast extract, and 10 gm sodium chloride in 950 ml distilled water.The pH of medium was adjusted to 7 then the volume was completed to one liter, and then sterilized by autoclave (Sambrook et al., 1981).

Dry sterilization
Glasswares were sterilized using oven instrument at 180°C for two hr.

Autoclaving
All the media, solutions and used in this work were autoclaved at 121°C for 15 min.

pH of Culture Media
The hydrogen ion concentration (pH) for all culture media was adjusted to (7.2 -7.4) using pH meter.

Microscopical Examination (Gram Staining Film)
Smears were prepared by taken a small amount of isolated colony from a bacterial culture on a glass slide by mixing a colony of tested bacterium with a drop of distilled water, stained with Gram stain and examined using oil immersion objective lens under 100X power.

Cultural Characteristics
The morphological characteristics of isolated colonies were carefully studied with the aid of a lens 10X lens.
Depending on above two criteria the cultures were primarily classified as pure or mixed cultures.

Antibiotic Resistance
A. Antibiotic sensitivity test (Antibiotic susceptibility test by disk-diffusion method (Kirby Bauer test) A single colony of bacterial strain was transferred to a fresh test tube containing 5 ml Brain-Heart infusion broth then incubated for 24 hours at 37°C.After that 0.1 ml of the inoculum was transferred to a Muller-Hinton agar plate, streaked by a sterile straight wire all over the surface of the medium three times.After 10-15 min, antibiotic discs were plated on the medium then incubated at 37°C for 24 hours.After incubation the inhibition zone diameters were determined in millimeters (mm), comparison was done with standard inhibition zone (Mahon & Manuselis, 2000) Table 4.The Mullar-Hinton agar was prepared and sterilized by autoclave, cooled to 50°C.Antibiotic solution in appropriated concentration was added to the cooled culture medium, poured into sterilized Petri dish and left to solidify, then.The bacterial isolates were cultured by picking and patching method.The result were recorded by presence (+) or absence of growth (-) (Al-zaaq, 1987;Nassif et al., 1989).Alkaline lysis method of Kado and Liu (1981) was used to extract large plasmids and the salting out method was used to prepare total DNA (Pospiech & Neuman, 1995) 1.A single colony of bacterial isolate was incubated into LB agar plates that containing 150 µg/ml of ampicillin.Then the plates were incubated at 37°C for 24 hrs.
2. The bacterial cells were collected by sterilized loop and transfer to polypropylene tube with plastic cap containing 5 ml of STE buffer.
3. The bacterial cells were precipitated by centrifugation at 3000 xg for 15 min.the supernatant was discarded and the pellet was resuspended by 5 ml of STE buffer.
4. Aliquot of 600 µl of 25% SDS solution and 120 µl of proteinase K (20 mg/ml) were added to the bacterial suspension and incubated in water bath at 55°C for 2 hrs.
5. Aliquot of 2 ml of 5 M NaCl solution was added to the lysate, then mixed by inversion, and left to cool to 37°C.
6. Equal volume of phenol-chloroform-isoamyl alcohol mixture (24:24:1) was added to the lysate then mixed gently by inversion for 30 min until an emulsion formed.

7.
The mixture was separate by centrifugation at 12000 rpm for 10 min at 4°C.The aqueous phase was transferred by pipette to a fresh tube.(The steps 6 and 7 were repeated until no protein was visible at the interphase of the organic and aqueous phases).
8. Equal volume of chloroform was added to the aqueous phase that contains the nucleic acid and step 7 was repeated.9. Aliquot of 0.6% (v/v) isopropanole was added to the extract and mixed by inversion then the DNA was spooled onto a sealed pasture pipette rinsed in 70% cold ethanol then dissolved in 1-2 ml TE buffer pH 8.
B-Plasmid extraction by alkaline lyses: 1. Single colony of the bacterial isolate was grown in 10 ml of LB broth containing 50 mg/ml ampicillin and incubated at 37°C for 24 hr.with shaking.Bacterial cells were harvested by centrifugation at 10000 rpm for 10 min.
2. The pellet resuspended in 10 ml of EST/saline buffer.
3. The suspension centrifuged at 10000 rpm for 10 min.(the step 2, 3 repeated twice) 4. The pellet was resuspended in 0.2 ml of solution I, then transferred to sterile eppendorf tube and omitted for 5 minutes at room temperature.
5. Aliquot of 0.4 ml of solution II was added to the mixture and then the eppendorf tube was gently inverted for many times and omitted in ice bath for 15 min.
6. Aliquot of 0.3 ml of cold solution III was added to the mixture above and the eppendorf tube was inverted for many times before putting on ice bath for 5 min.
7. The mixture was centrifuged at 14000 xg for 5 min.
8. Aliquot of 0.5 ml of the supernatant was transferred to the new sterile eppendorf, then an equal volume of phenol-chloroform-isopropanole solution was added and mixed very well then the solution objected to centrifugation as previous step.
9. The upper layer was transferred to the new sterile eppendorf, and both the middle and lower layer omitted, this step was repeated till the protein was excluded from the solution.
10. Aliquot of 3 M of cold sodium acetate in ratio of 0.1 volumes was added to the supernatant that contain plasmid DNA and mixed very well.
11. Double volume of cold absolute ethanol was added to the suspension and mixed gently and then left at -10°C for two hr.
12. The mixture was centrifuged at 12000 rpm for 15 min.then the ethanol was excluded from the solution, and the pellet was washed by 70% ethanol and then centrifuged as in the previous step.
13.The eppendorf was inverted on sterile filter paper and the pellet dissolved in 50 µl of TE buffer and stored at -20°C (Sambrook et al., 1989): C-Determination of DNA concentration by spectrophotometer: Concentration of prepared DNA was estimated using spectrophotometer by applied this equation (Sambrook et al., 1989): Conc. of DNA µg/ml = optical density at 260 nm × dilution factor ×50 µg/ml

Gel Electrophoresis
According to method of Sambrook et al. (1989), agarose gel were prepared by dissolving 0.7 gm agarose powder in 100 ml of 1 X Tris-borate buffer ,heated to boiling in water bath.The gel was cooled to 60 °C then 100 µl of Ethedium bromide was added to final concentration of 0.5 µg/ml and mixed thoroughly.The edge of the a lean, dry glass plate was sealed with tape so as to form a mold and the mold set on horizontal section of the bench.
The comb was placed above the plate.The gel was poured into the mold (10×20 cm).After that the gel was allowed completely to set for 30-45 min at room temperature, the comb and surrounding former cover were removed and the gel soaked in a gel tank containing (1 X) Tris-borate buffer.15 µl of DNA samples were mixed with 3µl of loading buffer dye, Finally 10 µl of this mixture was loaded into the wells, then the gel tank were closed by lid and electrical leads was attached 1-5 v/cm was applied for 1-2 hr.After that the electric current turned off and removes the leads and the lid from the gel tank.The gel was examined by UV-light and photographed the gel.

Bacterial Conjugation
Day one: 1-A single colony of donor strain was inoculated in to 50 ml LB broth containing appropriated antibiotic.
2-A single colony of E. coli MM294 rif r recipient was inoculated in to 50 ml LB broth containing 100 µg/ml of rifampcin.
3-The cultures were incubated overnight at 37°C for 18 hr.with vigorous shaking or until OD 590 ≈ 0.54.
2-The pellet was resuspended in 50 µl of LB and the cells were transferred to 0.22 µm Millipore filter on LB agar plate.
3-The LB agar plates which contain Millipore filter were incubated at 37°C for 1-2 hr.
4-The cells were resuspended by placing filter in a tube containing 0.5 ml of 0.85% saline and agitating the tube on a vortex.
7-Aliquot of 0.1 ml of original overnight culture of donor and recipient was spread on the same medium to determine the frequency of antibiotic resistance spontaneous mutation.
8-0.1 ml of dilution 10 -6 and 10 -8 was spread on LB agar containing rifampcin (100 µl/ml) to estimate the number of recipient cells in the mating.9-All plates were incubated at 37°C.

Control:
A-Aliquot of 0.1 ml of donor cells was transferred to rifampcin plate.
B-Aliquot of 0.1 ml of recipient cell Escherichia coli MM294 rif r were transferred to Plates containing antibiotic of donor strain.9-All plates were incubated at 37°C.

Day three:
The colonies that had grown on the selection plate was counted and the number of bacteria per ml in mating mixture exhibiting the phenotype rifampcin (total recipient) and Rif r , Tp r (transconjugant)was calculated (O' Connell, 1984) The frequency of conjugation was calculated as below: No. Of transconjugants cells / ml Tranconjugant cells per Recipient cells No. of recipients cells / ml  3.2.12Transformation 3.2.12.1 Preparation of Competent Cells 1-A starting culture was prepared by adding freshly isolated single colony to 5 ml of nutrient broth medium and grown overnight at 37°C.2-Aliquot of 0.3 ml of starting culture was inoculated in to 60 ml of fresh nutrient broth medium and the cells were grown at 37°C for 1-2 hr.
3-The culture was chilled on ice for 5-7 minutes; cell suspension was centrifuged at 8000 rpm for15 min in a sterile 100 ml glass centrifuge tube.4-The supernatant was discarded; the pellet was resuspended in half of original culture volume, (30 ml) of an ice-cold sterile solution of 0.1 M CaCl 2 .5-The cell suspension was placed on ice, and then centrifuged at 8000 rpm for 15 min.6-Supernatant was discarded and the pellet was resuspended in 1 ml of ice cold 0.1M CaCl 2 (Sambrook et al., 1989).
3.2.12.2DNA up Takes 1-For each 200 µl of competent cells in a transformation tube 10 µl of a DNA solution was added and incubated on ice bath for 30 min.
2-The competent cells were heat-shocked by placing the tube in a 42°C water bath for 90 Sec. and then 3 min.at ice bath.
3-Aliquot of 800 µl of pre wormed (37°C) SOC medium was added to the suspension and Incubated at 37°C with moderate agitation for 60 min.4-Aliquot of 0.1 ml cells were spread quickly and gently on selective plated, SOC agar plates by spreading.5-The plates were incubated upside down at 37°C over night.
6-The transformants colonies were calculated as below:

 
No. of transformants cells / Concentration of DNA g / ml Transformant frequency Competent cells µ  7-Co-transfer for transformant cells were made on different plates containing different type of antibiotics (Sambrook et al., 1989).

Results and Discussion
4.1 Re-identification of K.pneumoniae No.10 Isolate K. pneumoniae No. 10 had previously been isolated by (Hamad, 2006), which re-identified by using api 20 E. as in Figure 1.The isolate was resistant to most antibiotics including ampicillin, tetracycline, streptomycin, kanamycin, trimethoprim, Chloramphenicol, and nalidixic acid (Table 5).
The wide spread use of β-lactamase groups of antibiotic against bacterial infection and continued mismanaged selective pressure has contributed toward the emergence of extended spectrum-β-lactamase resistance bacteria (Cohen, 1992).It demonstrated that β-lactamase which was associated with high level ampicillin resistance in K. pneumoniae strains are mainly produced by large plasmid pK1 (Livermore, 1995).Philippon et al. (1989) indicated that one large plasmid encoding multidrug resistance genes usually carry one β-lactamase encoded gene, which is probably a mutant of the TEM-1 gene to code for enzyme capable of hydrolyzing the extended -spectrum β -lactam.

Study of Plasmid Contents in K. pneumoniae No. 10 Isolate
Upon mating of rifampicin resistant E. coli MM294 with K. pneumoniae No. 10 ampicillin, tetracycline-resistant Tranconjugant (TR 1 ) was selected at frequency of 7.25×10 -4 per recipient.The 55 kb conjugative plasmid, which confers ampicillin, tetracycline resistance, was successfully transferred to E. coli MM294 by conjugation.Peterson et al. (1982) referred that when two or more plasmids reside in the same cell, they may coexist stably without affecting one another, or may interact in some way.One possible interaction is physical exchange of segments of DNA.
Prodinger et al. (1996) mentioned that there was R plasmid with 80 kbp responsible for conferring resistance to SHV-5 in K. pneumoniae isolates.This R plasmid transfer between species of family Enterobacteriaceae in nosocomial outbreak stresses the need plasmid typing, especially because SHV-5 beta-lactamase seems to regionally spread predominately via plasmid transfer.Shannan et al. (1998) showed that 70 to 160 kbp of conjugative plasmid responsible for encoding the SHV-4, TEM-15 and TEM-16 in K. pneumoniae.Li and Lim (2001) showed novel large plasmid (97 ~ 145Kbp) carrying multiple β -lactamase resistance genes isolated from K. pneumoniae strain.

Conclusions
The detection of transposon encoding an extended-spectrum β-lactamase (ampicillin) on large plasmid pKpI in K. pneumoniae isolate No.10 from patients suffer from upper respiratory inflammation in hospital where large quantities of extended-spectrum β-lactam antibiotic are used , raises concern for the increased spread of resistance to this group of antibiotics.
It has been concluded that gene responsible for conferring resistance to ampicillin reside in a 5.000 bp mobile DNA segment or transposon which have ability to translocated themselves by both Intramolecular and intermolecular transposition.
We deduced that transposon which conferring ampicillin resistances in K.pneumoniae I and transposed via co-integrate formation is belonging to Tn3 family.
Translocation of ampicillin transposon accompanied with disturb of regular or structural genes function due to insertion inactivation of this transposon to those genes.
Transposition of transposon that carry ampicillin determinant was more in 30°C than 37°C, consequently the total change in antibiotic susceptibility pattern for K.pneumoniae I that grew at 30°C was more than Klebsiella pneumoniae I that grew at 37°C.

Recommendation
This study advises to determine nucleotide sequence and G-C ratio of this transposon which confers ampcillin resistance to K. pneumoniae in order to confirm whether our transposon is similar to Tn3 family or not.We also recommend further analyzing of this transposon by using suitable DNA probes of the Tn3 family transposon family and hybridized them with our transposon for further identification.Finally we advise for further Identification of the type of beta-lactamase that expressed by our transposon by isoelectric focusing and determine the type of beta-lactamase.

Figure 2 .
Figure 2. The plasmid profile of the transconjugant bacterial cells of E. coli MM294 From left to right: Lane 1: DNA content of Klebsiella pneumoniae isolate; Lane 2: DNA content of transconjugant E. coli; Lane 3: DNA content of standard plasmidless strain E. coli MM294; Lane 4: R751 plasmid (51 Kbp).
Antibiotic disc used in antibiotic susceptibility test

Table 6 .
The transformation frequency and number of transformant colonies among four strains of Klebsiella pneumoniae isolates.