Bacteria as a vehicle in cancer therapy and drug delivery

Although the conventional therapies have obviously improved the conditions of patients with cancer, some mechanisms of resistance have led scientists to use alternative agents that can penetrate in most solid tumors. Furthermore, the success of cancer therapies depends on limiting the uptake of toxins to normal tissues and their selectivity towards malignant cells. The involvement of natural and genetically modified non-pathogenic bacterial species, as potential antitumor agents, has led scientists to study bacteria and their products as an ideal vector for delivering therapeutic components to tumors. Moreover, bacterial ghosts, microbots and bactofection are the other strategies to destruct the malignant tissues. Although it has shown to achieve successful results in vivo, further investigations on the targeting mechanisms of the bacteria are needed to make it a complete therapeutic approach in cancer treatment

Determination of antibiotic resistance in clinical isolates of coagulase negative Staphylococci from hospitalized patients in selected hospitals of Tehran

To investigate the prevalence of methicillin and aminoglycoside resistance and gene encoding staphylococcal cassette chromosome mec [SCCmec] and aminoglycoside modifying enzymes in clinical isolates of coagulase negative staphylococci[CoNS] from hospitalized patients. One hundred and three isolates of coagulase negative staphylococci[CoNS] were recovered from various clinical samples from August 2013 to November 2014. All the specimens were identified by conventional microbiological methods. These tests were contained colony morphology, gram stain, catalase, slide and tube coagulase. To determine the sensibility of CoNS to antimicrobial components including Cefoxitin[30 micro g], Tobramycin[10 micro g], Kanamycin[30 micro g], Amikacin[30 micro g] and Gentamicin[10 micro g], disk diffusion method was performed by Kirby Bauer antibiotic testing. In order to show the presence of methicillin and aminoglycoside resistant CoNS genes, PCR were demonstrated. In our study the rate of resistance to Cefoxitin, Kanamycin, Gentamicin, Tobramycin and Amikacin were 74[71.8%], 54[52,4%], 51[49.5%], 45[43.7%] and 16[15.5%], respectively. Some strains of CoNS have been detected with intermediate resistance to Kanamycin 4[3.9%], Tobramycin and Amikacin 2[1.9%]. In our study, the distribution of mecA gene among clinical isolates of CoNS was 89[86.4%]. The prevalence of aminoglycoside resistance genes like ant[4 ']-Ia, aac[6 ']/aph[2 "] and aph[3 ']-IIIa were 89[86.4%], 87[84.5%] and 68[66%], respectively. The rate of coexistence of aac[6']-Ie-aph[2''] with aph[3']-IIIa and aac[6']-Ie-aph[2''] with ant[4']-Ia was 65[63%] and 77[74%], respectively. Resistance to aminoglycosides, develops quickly in coagulase-negative staphylococci from clinical areas where these antimicrobial agents are widely used. Therefore, higher investments should be directed towards identifying coagulase-negative staphylococcus species in healthcare institutions and in the community. Overall, Knowing the epidemiology and antibiotic resistance of CoNS is essential to implement the prevention strategies and reducing antibiotic consumptions

Prevalence of blaCTX-M gene in multi-resistant escherichia coli isolated from urinary tract infections, Tehran, Iran

The emergence and increase in the incidence of Extended-spectrum beta lactamase [ESBL] producing Escherichia coli [E. coli] has become an emerging challenge especially in hospitalized patients with urinary tract infection [UTI]. The aim of the present study was to survey the frequency of bla CTX-M genotype in ESBL producing E. coli isolated from hospitalized patients with urinary tract infection and determination of their antibiotic resistance pattern. A total of 135 E. coli isolates were collected and isolated from patients with UTI. The isolates were subjected to confirmatory phenotype tests for the presence of ESBL. 75 E. coli isolates were confirmed as ESBL-positive by double disc synergy test. In vitro susceptibility of ESBL isolates to 15 antimicrobial agents amoxicillin, penicillin, ceftazidime, cefotaxime, cefoxitin, ceftriaxone, cefixime, cephalexin, co-trimoxazole, gentamicin, nalidixic acid, ciprofloxacin, nitrofurantoin, amikacin, and imipenem was performed by Kirby-Bauer's Disk diffusion method according to Clinical and Laboratory Standards Institute [CLSI, 2012] guideline. PCR method was used to identify bla CTX-M gene in 75 ESBL positive strains. PCR and sequence analysis showed that 75 [55.5%] isolates produced bla CTX-M genes. In vitro susceptibility of ESBL producing E. coli showed that all of them were resistant to amoxicillin and penicillin. The rates of resistance to the majority of tested antibiotics varied among 61% to 100%, with the exception of amikacin [14.7%] and imipenem [2.7%]. Our results showed that the frequency of bla CTX-M was strikingly high [93.3%] in patients with UTI. These data confirmed that the frequency of bla CTX-M genes was high among E. coli isolated from patients with UTI. The trend of multidrug-resistant profile has been associated with bla CTX-M gene is alarming. Therefore, it is very important to establish a routine screening of ESBL in clinical isolates to prevent dissemination of resistant isolates in health care settings