1. Screening for MDR-hvKP causing VAP in patients admitted to chest ICU in Assiut University Hospital.
2. In vitro evaluation of the synergistic activity of combined meropenem/levofloxacin with and without kasugamycin against clinical MDR-hvKP isolates by checkerboard and time killing assay.
3. In vivo evaluation of the synergistic activity of combined meropenem/levofloxacin with and without kasugamycin using MDR-hvKP septic rat model.

New "hypervirulent" Klebsiella-pneumoniae (hvKp) strain has emerged as a clinically-significant-pathogen in both healthy and immunocompromised individuals . HvKp, at its discovery, was rarely resistant to antimicrobial-agents , however, nowadays, antibiotic-resistant hvKP isolates are being reported .

Plasmids are important vectors that bacteria use to transfer resistance and virulence determinants. Typically, genetic elements conferring resistance and virulence were encoded by different plasmids . Most recently, clinicians have been faced, the confluence of resistance and virulence-determinants on the same or coexisting-plasmids with the evolution of multidrug-resistant (MDR) and hypervirulent Klebsiella pneumoniae hvKP .

One approach to combat MDR infections is to combine antimicrobial drugs during a treatment-regimen . Fluoroquinolone plus carbapenems is one of-the most useful-combination used in cases which suffer from MDR to most available monotherapies . Another-approach is Plasmid curing, using plasmid inhibitors, which is the method of removing plasmids from the bacterial populations while leaving the population intact leading to reversal of the plasmid-mediated antibiotic resistance .

Kasugamycin, an-aminoglycoside; is a compound exhibiting significant-antiplasmid activity-up-to-complete suppression of plasmid-replication . Kasugamycin was found to block plasmid replication by inhibiting-expression of plasmid replication initiation-protein, RepE, and to reduce plasmid-levels by 90% . Accordingly, we hypothesize that, using dual-antibiotics supplemented with plasmid inhibitor will be efficient in inhibiting MDR-hvKP, both in vitro and in vivo.

This is the first-study to evaluate the effect of addition of plasmid inhibitor on improving the efficacy of antibiotics and improve their synergistic activity. The results of this study will open the door for-using plasmid-inhibitor-compounds on restoring the usefulness of many conventional-antibiotics to which-resistance has emerged.

Inclusion Criteria:

VAP patients (patients under mechanical ventilation for more than 48 h with new or progressive infiltrate on chest X-ray and have at least two of the following criteria:

1. Fever (>38 oC) with no other recognized cause
2. WBCs < 4000/mm3 or >12000/mm3
3. New onset of purulent sputum.
4. Increase in respiratory secretion or increased need for suctioning.
5. New-onset or worsening cough, or dyspnea, or tachypnea worsening gas exchange.

Exclusion Criteria:

Patients with chest diseases other than VAP .

Fifty VAP patients with no other chest diseases will be included in the study.