Detection of Biofilm Formation of Klebsiella Pneumoniae Isolated from Medical Devices at the University Hospital of Tlemcen, Algeria

Background: Klebsiella pneumoniae is a major cause of community-acquired and nosocomial infections. This germ is responsible for acute and chronic infections, most of which are due to its ability to adhere to medical implants and form a biofilm. The objective of this work is to study the interaction between clinical isolates of K. pneumoniae and abiotic surfaces (medical devices) and some factors influencing biofilm formation. Methods: Over a period of 2 years, 115 strains of K. pneumoniae were isolated from medical devices CHU Tlemcen, most of which had a high level of resistance to cephalosporins 1st, 2nd, and 3rd generation.  Their capacity to form biofilm was assessed using two 3 techniques: TCP, TP, and RCA.  We determined in vitro the effects of three antimicrobial agents against planktonic and biofilm forms of K. pneumoniae. The presence of MrkD genes was detected by polymerase chain reaction (PCR). Results: According to the studied (TCP, TP, RCA) strains of K .pneumoniae isolated from urinary catheters have proved very good, forming the biofilm to those isolated from other medical devices. 24 of 115 isolated strains showed a clear difference in antibiotic susceptibility between planktonic populations and biofilm populations. They were 10-20 times higher. All strains presented a highly hydrophilic character and adhesion 2-10 times greater in PVC with respect to glass support. The MrkD gene (detected by PCR) responsible for biofilm formation was found in 22 strains of K. pneumoniae, which may explain their adhesion and therefore their pathogenicity. Conclusion: Our results show the great ability of K.pneumoniae strains to form a biofilm on medical devices, and the isolates were at least 10 times more resistant than their planktonic counterparts. In addition, we showed that the presence of type 3-encoding gene mrkD was associated with high adhesion indexes

Development of new antibacterial agents

Background: Antibiotics, as miraculous drugs, have been used extensively to confront fatal infection, even without prescriptions. However, the inappropriate and disproportionate use of antibiotics have led to the emergence of new drug-resistant bacteria1, which causes a high risk of serious diseases and dramatically aggravates the clinical complications in hospitals. Methods: By using the peptide coupling protocol, a simple straightforward synthesis of functionalized aziridines has been developed. By means of this synthetic strategy from readily available N-phtaloyl acide and 2-methylbenzosulfonate aziridine using DCC as coupling agent, new tosylates aziridines could be obtained. The coupling reactions occurred without a ring opening of the three membered ring. Results: This work describes new results of our ongoing research targeting new derivatives of biological interests. All the compounds were screened for their antibacterial activity; they all showed comparable moderate to good growth inhibitory activity with reference to tetracyclin and gentamicin. Conclusion: In conclusion, we reported the synthesis and a preliminary antibacterial evaluation of novel functionalized tosylaziridines. The synthetic strategy relies on the coupling reactions between tosylaziridines and amino acids. Moreover, and besides showing interesting antibacterial activities, the series of novel compounds can be further improved to serve as potential drug against nosocomial diseases

EVALUATION OF ANTIBACTERIAL ACTIVITIES OF NOVEL AZIRIDINYL PHOSPHONATES

A new series of aziridines was synthesized in our laboratory, which displays potent antibiotic activities. However, a practical synthesis by using the coupling method of this aziridines with either phosphonate or N-phtaloyl acide moiety can be converted into various derivatives. This work describes new results of our ongoing research targeting new derivatives of biological interest. All the compounds were screened for their antibacterial activity, they all showed comparable moderate to good growth inhibitory activity with reference to Tetracyclin and Gentamicin