A novel antibacterial approach of Cecropin-B peptide loaded on chitosan nanoparticles against MDR Klebsiella pneumoniae isolates.

Egypt has witnessed the emergence of multidrug-resistant (MDR) Klebsiella pneumoniae, which has posed a serious healthcare challenge. The proper treatment choice for MDR-KP infections is not well determined which renders the problem more complicated, thus making the control of such infections a serious challenge for healthcare professionals. This study aims to encapsulate the cationic antimicrobial peptide; Cecropin-B (Cec-B), to increase its lifetime, drug targeting, and efficacy and study the antimicrobial effect of free and encapsulated recombinant rCec-B peptide on multidrug-resistant K. pneumoniae (MDR-KP) isolates. Fifty isolates were collected from different clinical departments at Theodore Bilharz Research Institute. Minimal inhibitory concentrations (MICs) of rCec-B against MDR-KP isolates were determined by the broth microdilution test. In addition, encapsulation of rCec-B peptide into chitosan nanoparticles and studying its bactericidal effect against MDR-KP isolates were also performed. The relative expression of efflux pump and porin coding genes (ArcrB, TolC, mtdK, and Ompk35) was detected by quantitative PCR in treated MDR-KP bacterial isolates compared to untreated isolates. Out of 60 clinical MDR isolates, 50 were MDR-KP. 60% of the isolates were XDR while 40% were MDR. rCec-B were bactericidal on 21 isolates, then these isolates were subjected to treatment using free nanocapsule in addition to the encapsulated peptide. Free capsules showed a mild cytotoxic effect on MDR-KP at the highest concentration. MIC of encapsulated rCec-B was higher than the free peptide. The expression level of genes encoding efflux and porin (ArcrB, TolC, mtdK, and Ompk35) was downregulated after treatment with encapsulated rCec-B. These findings indicate that encapsulated rCec-B is a promising candidate with potent antibacterial activities against drug-resistant K. pneumoniae.

Detection of ERG11 gene in fluconazole resistant urinary candida isolates.

Candida species resistant to fluconazole and voriconazole were screened for the presence of ERG11gene by polymerase chain reaction (PCR). Also, the association of this gene with the demonstration of Candida virulence factors; biofilm formation, phospholipase and proteinases activities were studied. A total of 61 Candida isolates were collected from urine specimens. Candida species were identified by API 20 C Aux test. Extracellular phospholipase, secretory aspartyl proteinase and biofilm formation were determined. ERG11 gene was detected by PCR. C. albicans was identified in 34.5%, C. glabrata in 29.5% and C. tropicalis and C. krusei in 18% each. Candida species was resistant to fluconazole and voriconazole in 55.7% and 27.9%, respectively. Seventeen (50%) of fluconazole resistant Candida isolates were sensitive to voriconazole. The most frequently Candida species revealed fluconazole resistance were C. glabrata (47.1%), C. krusei (29.4%), and C. tropicalis and C. albicans (11.8% each). Biofilm formation, phospholipase and proteinase activity were determined in 41.2%, 67.6% and 35.3% of fluconazole resistant Candida isolates, respectively. Erg 11 gene was determined in 82.4% of fluconazole resistant Candida isolates and prominent in C. glabrata (93.75%), followed by C. krusei (90%), C. tropicalis (75%) and C. albicans (25%). Erg 11 gene was detected in 64.7% (11/17) of fluconazole resistant-voriconazole sensitive Candida isolates. Regarding, correlation of Erg11 gene positivity and virulence factors among fluconazole resistant Candida isolates, 34.5% exhibited biofilm formation and 62.1% and 31% showed phospholipase and proteinase activities, respectively. There were statistically significant difference concerning the association of proteinase activities and Erg 11 gene expression among fluconazole resistance Candida isolates (P=0.04). The study emphasizes the high prevalence of Erg11 gene among fluconazole resistant Candida species. There was association between the proteinase activity, fluconazole resistance and the presence of Erg11 among Candida species. Voriconazole maintains better activity towards Candida species and represent an alternative therapy.

High Rates of Aminoglycoside Methyltransferases Associated with Metallo-Beta-Lactamases in Multidrug-Resistant and Extensively Drug-Resistant Pseudomonas aeruginosa Clinical Isolates from a Tertiary Care Hospital in Egypt.

BACKGROUND: Multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Pseudomonas aeruginosa are the leading cause of healthcare-associated infections worldwide. OBJECTIVE: The aim was to identify the resistant phenotypes among P. aeruginosa and to characterize different aminoglycosides and carbapenem resistance genes as major mechanisms of resistance in these isolates, in Theodor Bilharz Research Institute (TBRI), a tertiary care hospital in Cairo, Egypt. METHODS: During a period of 11 months, 42 P. aeruginosa clinical isolates were collected from the microbiology laboratory by routine culture. Antimicrobial sensitivity testing to the aminoglycosides gentamicin and amikacin, and other classes of antibiotics, was performed by a disk diffusion method. Isolates were tested for aminoglycoside resistance genes, aac(6')-lb, aac-(3)-lla, rmtB, rmtC, armA, rmtD, and rmtF, and carbapenemase resistance genes bla NDM, bla VIM, and bla IMP, using conventional PCR. RESULTS: Thirty-three (78.5%) of the clinical P. aeruginosa isolates showed MDR and XDR phenotypes at 42.4% and 57.65%, respectively, and these were included in the study. Aminoglycoside resistance was found in 97%, whereas carbapenem resistance was found in 81% of the isolates phenotypically. Only 59.4% (19/26) of the aminoglycoside-resistant isolates harbored resistance genes; none of the amikacin-susceptible isolates harbored any of the tested aminoglycoside resistance genes. Aminoglycoside resistance genes rmtB, armA, aac(6')-lb, and rmtF were found at rates of 17/33 (51.5%), 3/33 (9%), 2/33 (6%), and 2/33 (6%), respectively, whereas rmtD, acc(3)-II, and rmtC were not detected. Only 40.7% (11/27) of the carbapenem-resistant isolates harbored resistance genes. Carbapenem resistance genes, bla NDM andbla VIM, were found at rates of 7/33 (21.2%) and 6/33 (18.1%), respectively, and bla IMP was not detected. CONCLUSION: Rates of MDR and XDR P. aeruginosa and resistance to aminoglycosides and carbapenems in our setting are high. Methyltransferases and metallo-beta-lactamases are the main mechanisms of resistance to aminoglycosides and carbapenems, respectively. The presence of bla NDM and rmtF in the strains confirms their rapid dissemination in the Egyptian environment.