Biofilm formation in clinical isolates of nosocomial Acinetobacter baumannii and its relationship with multidrug resistance

Objective: To check biofilm formation by Acinetobacter baumannii (A. baumannii) clinical isolates and show their susceptibility to different antibiotics and investigate a possible link between establishment of biofilm and multidrug resistance. Methods: This study was performed on clinical samples collected from patients with nosocomial infections in three hospitals of Tehran. Samples were initially screened by culture and biochemical tests for the presence of different species of Acinetobacter. Identifications were further confirmed by PCR assays. Their susceptibilities to 11 antibiotics of different classes were determined by disc diffusion method according to Clinical and Laboratory Standards Institute guidelines. The ability to produce biofilm was investigated using methods: culture on Congo red agar, microtiter plate, and test tube method. Results: From the overall clinical samples, 156 specimens were confirmed to contain A. baumannii. The bacteria were highly resistant to most antibiotics except polymyxin B. Of these isolates, 10.26% were able to produce biofilms as shown on Congo red agar. However, the percentage of bacteria with positive biofilm in test tube, standard microtiter plate, and modified microtiter plate assays were 48.72%, 66.66%, and 73.72%, respectively. At least 92% of the biofilm forming isolates were multidrug resistant. Conclusions: Since most of the multidrug resistant strains produce biofilm, it seems necessary to provide continuous monitoring and determination of antibiotic susceptibility of clinical A. baumannii. This would help to select the most appropriate antibiotic for treatment.

Antimicrobial effect of imipenem-functionalized Fe[2]O[3] nanoparticles on pseudomonas aeruginosa Producing Metallo beta-lactamases

Background: Resistant strains of Pseudomonas aeruginosa to imipenem was medical treatment problem, especially in burnt units of hospitals

Objectives: This study was conducted to evaluate the antimicrobial effect of Fe[2]O[3] nanoparticles alone and functionalized with imipenem on P. aeruginosa starins producing metallo beta-lactamases [MBL]

Materials and Methods: A disk diffusion method was used to isolate a clinical P. aeruginosa producing Metallo beta-lactamases with imipenem resistance. The minimum inhibitory concentration [MIC] of Fe[2]O[3] nanoparticles and imipenem were calculated against the bacteria. The antimicrobial effect of nanoparticles functionalized with the antibiotic was determined. Standard strain of P. aeruginosa ATCC: 27853 was used as control

Results: The clinical sample was resistant to imipenem [up to 28 micro g.mL[-1]]. Similarly, MIC of the nanoparticles against the isolate was 160 micro g.mL[-1]. Subsequently, the combination of 16 pg.mL[-1] of antibiotic with 80 micro g.mL[-1] of Fe[2]O[3] nanoparticles were able to inhibit the growth of the isolate

Conclusions: Fe[2]O[3] nanoparticles functionalized with imipenem can impair antibiotic resistance mechanisms of bacteria as it can make the imipenem resistant the aforementioned bacterium more susceptible to weaker concentrations of antibiotic. It also has its own antibacterial effect in certain concentrations

Detection of Pseudomonas aeruginosa by a triplex polymerase chain reaction assay based on lasl/R and gyrB genes

Pseudomonas aeruginosa is a nosocomial pathogen, which, due to its inherent and acquired resistance to a wide range of antibiotics, causes high mortality rates. Therefore, rapid detection of the bacterium with high specificity and sensitivity plays a critical role in the control of the pathogenic bacterium. The aim of this study was to evaluate the accuracy and specificity of a prompt detection of the bacterium based on a triplex polymerase chain reaction that amplifies the last, lasR and gyrB genes. For this purpose, 30 clinical isolates of P. aeruginosa and 30 wound biopsy samples were retrieved from clinical diagnostic laboratories. After the extraction of the chromosomal DNA, the desired genes were amplified using uniplex and triplex PCR with appropriate primers. The specificity of the primers was evaluated by a comparison of the PCR results for P. aeruginosa clinical samples and non-Pseudomonas species control samples. The sensitivity of the primers was determined using a serial dilution of the genomic DNA template [100ng to 100fg] and by a comparison of the PCR and bacterial culture results. The results showed that the triplex PCR assay was positive for all of the samples [100%], while the PCR identifications were negative for non-Pseudomonas species. Additionally, at 10[-4] and 10[-5] diluted genomic DMA from P. aeruginosa [10 pg and 1 pg], the triplex PCR test was positive for the Las and gyrB genes in all of the samples, respectively. Based on these results, the designed primers can be used for the rapid, specific and sensitive diagnosis of P. aeruginosa in a triplex PCR assay

Curcumin-loaded chitosan tripolyphosphate nanoparticles as a safe, natural and effective antibiotic inhibits the infection of Staphylococcus aureus and Pseudomonas aeruginosa in vivo

Curcumin as a yellow natural compound extracted from turmeric root is known it as an antibacterial agent. One of the nanoparticles ability is to decrease the defects of usual drug delivery systems. Chitosan is a low toxic, biodegradable, biocompatible and safe polymer which is used in production of nanoparticles. Nanoparticles like chitosan-tripolyphosphate [TPP] are able to increase antibacterial properties of curcumin. Curcumin-loaded chitosan-TPP nanoparticles containing chitosan, curcumin and TPP salt were synthesized by ionotropic gelation methods. First, the skin of anesthetized mice was inoculated with staphylococcus aureus and pseudomonas aeruginosa suspension. Then the infected mice were treated with curcumin-loaded chitosan-TPP nanoparticles for 3 days. Following that, antibacterial characteristics of the mice treated with curcumin-loaded chitosan- TPP nanoparticles were evaluated by bacterial culture of these mice. Our results showed the size of 160 +/- 10 nm and the charge of +7 +/- 2 mV in curcumin-loaded chitosan-TPP nanoparticles. These nanoparticles were also spiral shape. The encapsulation efficiency of curcumin in chitosan-TPP nanoparticles was 75 +/- 2%. Bacterial culture showed that curcumin-loaded chitosan-TPP nanoparticles inhibited staphylococcus aureus and pseudomonas aeruginosa growth. Our study demonstrated that curcumin-loaded chitosan-TPP nanoparticles can be utilized as a potent agent in treatment of Staphylococcus aureus and Pseudomonas aeruginosa infections

Antibiotic resistance and carriage class 1 and 2 integrons in clinical isolates of Acinetobacter baumannii from Tehran, Iran

<p><b>OBJECTIVE</b>To investigate antibiotic resistance and carriage class 1 and 2 integrons in clinical isolates of Acinetobacter baumannii (A. baumannii) from Tehran, Iran.</p><p><b>METHODS</b>Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The presence of integrons was investigated by PCR using specific primers.</p><p><b>RESULTS</b>Among isolated A. baumannii strains, 82% were multidrug resistant, 27 samples (54%) were resistant to three or more than three antibiotics and 16 samples (32%) showed resistance to two antibiotics. Integrons were detected from 44 of 50 isolates (88%), with classes 1 and 2 being observed in 42% (21/50) and 82% (41/50) of isolates, respectively. Integron-positive A. baumannii isolates showed higher antibiotic resistance than integron-negative isolates and all showed a multidrug-resistant phenotype.</p><p><b>CONCLUSIONS</b>Our findings show that classes 1 and 2 integrons, and especially classes 2 integrons are widely disseminated among A. baumannii strains isolated from Tehran and these structures are playing a major role in the acquisition of multidrug resistance in these strains. So monitoring of drug resistance with investigating carriage class 1 and 2 integrons is very important to plan specific infection control measures due to multidrug resistance A. baumannii in Iran hospitals.</p>

A duplex PCR for rapid and simultaneous detection of Brucella spp. in human blood samples

OBJECTIVE@#To design a duplex PCR for rapid and simultaneous detection of Brucella species. in human blood samples.@*METHODS@#Fifty-two peripheral bloods samples were collected from suspicious patients with brucellosis. Following DNA extraction, PCR assay were performed, using three primers that could simultaneously identify and differentiate three major species of pathogenic Brucella in humans and animals.@*RESULTS@#Of the 52 peripheral bloods samples tested, 25 sample (48%) showed positive reactions in PCR. Twelve samples were positive for Brucella abortus 39 (B. abortus 39) (23%), 13 for Brucella melitensis 39 (B. melitensis 39) (25%) and 0 for Brucella ovis 39 (B. ovis 39) (0%).@*CONCLUSIONS@#This work demonstrates that in case where specific primers were utilized, duplex PCR has proved to be a simple, fast, and relatively inexpensive method for simultaneous detection of important species of Brucella in clinical samples.

Antibiotic resistance and carriage class 1 and 2 integrons in clinical isolates of Acinetobacter baumannii from Tehran, Iran

Objective: To investigate antibiotic resistance and carriage class 1 and 2 integrons in clinical isolates of Acinetobacter baumannii (A. baumannii) from Tehran, Iran. Methods: Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The presence of integrons was investigated by PCR using specific primers. Results:Among isolated A. baumannii strains, 82%were multidrug resistant, 27 samples (54%) were resistant to three or more than three antibiotics and 16 samples (32%) showed resistance to two antibiotics. Integrons were detected from 44 of 50 isolates (88%), with classes 1 and 2 being observed in 42% (21/50) and 82%(41/50) of isolates, respectively. Integron-positive A. baumannii isolates showed higher antibiotic resistance than integron-negative isolates and all showed a multidrug-resistant phenotype. Conclusions:Our findings show that classes 1 and 2 integrons, and especially classes 2 integrons are widely disseminated among A. baumannii strains isolated from Tehran and these structures are playing a major role in the acquisition of multidrug resistance in these strains. So monitoring of drug resistance with investigating carriage class 1 and 2 integrons is very important to plan specific infection control measures due to multidrug resistance A. baumannii in Iran hospitals.

Comparison of culture and multiplex PCR technique for detection of brucella abortus and brucella melitensis from human blood samples

To compare culture methods with multiplex PCR technique for identification of Brucella abortus and Brucella melitensis from suspicious patients with clinical history of brucellosis and positive serological test [Rose Bengal test and serum agglutination test]. In this study, 160 blood samples from patients suspected of Brucellosis with high serum titers of 1/80 were studied. All samples were cultured in Brucella-specific media. Brucella species were identified by using microbiological methods. DNA was extracted with Phenol-chloroform DNA extraction method. IS711 was amplified simultaneously using three specific primers and obtained patterns were analyzed. From 160 samples, 47.5% [76] were culture positive cases from which 43 cases were B. melitensis and 33 were B. abortus With the PCR technique 108 were detected positive from which 45.3% were B. abortus and 54.6% were B. melitensis. It should be noted that all 76 samples with positive culture were also identified by PCR. Generally, use of the molecular technique multiplex PCR in addition to increased speed and accuracy and less false results than bacterial culture method, is able to identify different species of brucella. This will facilitate the treatment process

Simultaneous detection and differentiates of Brucella abortus and Brucella melitensis by combinatorial PCR

OBJECTIVE@#To evaluate simultaneous detection and differentiates of Brucella abortus (B. abortus) and Brucella melitensis (B. melitensis) through the combinatorial PCR method.@*METHODS@#This study was designed using three primers that could simultaneously identify and differentiate two major species of pathogenic Brucella in humans and animals. Identification and differentiation of each species using the size of the PCR product were determined. To determine the specificity of the method, bacteria close to the genus Brucella were used. Finally, to confirm PCR products, In addition to the products sequence, RFLP was performed on PCR products using restriction enzymes.@*RESULTS@#The method of optimized combinatorial PCR in this study could simultaneously detect and differentiate B. abortus and B. melitensis with high specificity and sensitivity in clinical samples. Differentiation of species is based on the resulting bands; therefore, the band 494 bp for B. abortus and 733 bp for B. melitensis were obtained. RFLP and sequencing results confirmed PCR results.@*CONCLUSIONS@#The results of this study shows that without routine diagnostic methods such as culture and serology tests, using the molecular method of combinatorial PCR, important species of Brucella can be simultaneously identified and differentiated in clinical samples.

Comparison of polymerase chain reaction and culture for detection of genital mycoplasma in clinical samples from patients with genital infections

Comparison of polymerase chain reaction [PCR] and culture for detection of genital mycoplasma [Mycoplasma hominis, Mycoplasma genitalium, and Ureaplasma urealyticum] in clinical samples from patients with genital infections. Duplicate genital swabs were taken from 210 patients, referred to the gynecology clinic of Rasool Hospital, Tehran, Iran between December 2007 and June 2008. They were transported to the laboratory in a selective mycoplasma transport medium and in phosphate buffer solution. The specimens were inoculated into specific broth and solid medium for culture. Characteristic mycoplasma colonies were determined with Diennes' stain and examined microscopically. For PCR, samples were analyzed with genus specific primers. The primer sets, which were originally designed in our laboratory, amplified a 465 bp fragment [Mycoplasma genitalium], 559 bp fragment [Ureaplasma urealyticum], and 630bp fragment [Mycoplasma hominis]. Samples containing a band of the expected sizes for mycoplasma strains were subjected to digestion with a restriction endonuclease enzyme. Of the 210 samples, mycoplasma strains were isolated from 83 patients [39.5%], [23 mycoplasma isolates, 11%; and 69 ureaplasma isolates, 32.9%] by using a selective mycoplasma isolation media. Using PCR, a total of 120 [57.1%] samples were found to be positive for mycoplasmas [28 mycoplasma spp., 13.3%; and 67 ureaplasma spp., 31.9%] and co-infections with both species were detected in 25 samples [11.9%]. The PCR was found to be highly sensitive when genus specific primers were used for diagnosis of genital mycoplasmas in comparison with culture

[Knowledge, attitude and practice of Iran University of Medical Sciences students about AIDS]

Young people are the major group at risk of acquiring AIDS worldwide. It seems that proper education and having knowledge about prevention methods is the most effective way for reducing the risk of HIV infection among this group. The aim of this survey was to elucidate the degree of knowledge, attitude, and practice of Iran University of Medical Sciences students about AIDS in 2006-2007. The study population consisted of 4237 students, from which 550 students were selected randomly based on each school/faculty student population. A self-administered questionnaire, consisted of questions regarding demographic data, knowledge, attitude, and practice about AIDS, was used to collect data. Data were analyzed by SPSS software. Most students in different grades and schools/faculties had high levels of knowledge [above 60%] about AIDS and its transmission routes. Among them, medical students had the highest level of knowledge, compared with other students [P<0.05]. Most students [75.8%] indicated that they had been previously informed about AIDS through mass-media [radio, TV]. Seventy five percent of the samples had positive attitude towards preventive methods and believed that by strictly observing preventive behaviors, it is not only possible to reduce the chance of disease transmission, but also, to interact with AIDS afflicted individuals, properly. Around 84.7% of the students believed that proper sterilization of instruments is adequate for virus eradication and 55.5% of them believed that chlorine bleaching of blood contaminated surfaces is the best disinfection method. The results of this survey indicate that importance of education through mass media and other means such as university books, in reducing the risk of AIDS transmission. Education of preventive methods, both in simple and sophisticated language can do the most in elevating the general knowledge of people about AIDS and its methods of transmission