Jundishapur Journal of Microbiology
Volume:7 Issue: 1, Jan 2014

AmpC type β-lactamases are commonly isolated from extended-spectrum Cephalosporin-resistant Gram-negative bacteria. Also, resistance appeared in bacterial species not naturally producing AmpC enzymes. Therefore, a standard test for the detection of the plasmid-mediated AmpC enzyme and new breakpoints for extended spectrum Cephalosporins are urgently necessary.. To detect plasmid and chromosomal mediated AmpC-β-lactamases in Gram negative bacteria in community and hospital acquired infections.. 1073 Gram negative clinical isolates were identified by the conventional methods and were screened for AmpC production using Cefoxitin discs. Confirmatory phenotypic identifications were done for the Cefoxitin-resistant isolates using Boronic Acid for combined and double disc synergy tests, Cloxacillin based double disc synergy test, and induction tests. The genotypic identification of plasmid-mediated AmpC was done using multiplex PCR. ESBL production was also screened by discs of Ceftazidime and Cefotaxime with and without Clavulanic Acid (10 μg).. The AmpC-producing isolates among all identified Gram negative bacilli were 5.8% (62/1073) as detected by screening disc diffusion methods, where 72% were positive for AmpC by combined disc method (Cefotetan and Boronic Acid), 56.5% were positive by each of Boronic Acid and Cloxacillin double disc synergy tests, 35.5% were positive by the induction test, and 25.8% were plasmid-mediated AmpC β-lactamase producers by the multiplex PCR. Plasmid-mediated AmpC genes retrieved, belonged to the families (MOX, FOX, EBC and CIT). ESBL producers were found in 26 (41.9%) isolates, 15 (57%) of which also produced AmpC. Isolates caused hospital acquired infections were (53/62); of which (39/62) were AmpC producers. While only (8/62) of the isolates caused community-acquired infections, were AmpC producers, and (1.6%) (1/62) were non AmpC producer.. The AmpC β-lactamases detection tests had to be included in the routine microbiology workup of Gram negative bacteria, namely Cefoxitin as a screening test, combined Boronic Acid disc test with Cefotetan, followed by synergy tests and finally by the induction test for phenotypic identifications. Multiplex PCR can successfully detect the plasmid AmpC genes..

Methicillin resistant coagulase-negative Staphylococci are resistant organisms causing infections associated with high morbidity and mortality. Methicillin resistant Staphylococcus epidermidis (MRSE), is especially important with respect to admitted patients with indwelling catheters and other installed invasive devices where these organisms are known to be found. As a result, such lifesaving measures may prove fatal from subsequent infection and sepsis by these pathogens. Therefore, to limit such conditions in patients, the spread of MRSE and related organisms in the hospitals have to be effectively controlled.. This study was carried out to determine the frequency of methicillin resistant organisms among all isolated coagulase negative Staphylococci (CoNS) and to find effective antibiotics against these microorganisms..Patients and All samples sent to the lab were routinely processed according to standard microbiological procedures and the cultures yielding growth of CoNS were selected for the study. All samples containing CoNS collected over a 2 year-period, were included irrespective of patients'' age and gender. The antibiogram of the organisms was recorded according to CLSI guidelines and the ratio of methicillin resistant organisms determined.. From a total of 299 isolated coagulase negative Staphylococci (CoNS), 40.1% o were methicillin resistant. A high proportion of these organisms (more than 50%) were resistant to cephalosporins, aminoglycosides and quinolones while only a small number were found to show resistance to linezolid, minocycline, chloramphenicol and rifampicin. There were no resistant organisms against vancomycin.. A considerable amount of methicillin resistant organisms found among CoNS in our region. The above stated antibiotics would prove effective in limiting these infections. Clinicians should keep these facts in mind while treating their patients..

Herpes simplex virus (HSV) is a member of Herpesviridae and a leading cause of human viral diseases. Meningitis occurs as a complication of HSV-1 or HSV-2 primary infection.. We aimed to evaluate HSV meningitis in children in Gorgan province, Iran.. Patients and Forty-five cerebrospinal fluid samples were taken from children referred with meningitis symptoms. Samples with negative bacterial culture results were tested for viral, biochemical and cytological assays. DNA extraction and PCR were performed.. HSV-1 detected in 4 (8.8%) samples without any HSV-2 infections. Cases with positive results had fever and CSF pleocytosis. Vomiting, headache and higher count of WBC were observed in 3, 2 and 3 cases respectively. The cerebrospinal fluid (CSF) glucose and protein levels were normal and 3 cases showed positive C-reactive protein (CRP) results. Also erythrocyte sedimentation rate (ESR) was higher than normal in all positive cases.. Distribution of HSV types in children with meningitis in our area predominantly was type 1 compared with type 2, which has been reported more in other area..

Biofilms are communities of bacteria attached to the surfaces in an extracellular polymeric matrix which are associated with many chronic infections in humans. Acinetobacter spp. are emerging as a major cause of nosocomial infections and Acinetobacter baumannii is the predominant species associated with this kind of infections.. In the present study, the potential of biofilm formation of clinical isolates, A. baumannii, was assessed by using crystal violet method. Furthermore, susceptibility pattern of these strains to ciprofloxacin and imipenem was determined..Methods and Materials: Biofilm formation by 75 A. baumannii isolates was evaluated by using microtiter plate and tube methods and crystal violet staining. Tube method was carried out under static and shaking conditions. Then, the susceptibility of isolates to ciprofloxacin and imipenem was determined.. Results showed that in tube method under shaking, 22% of clinical isolates were strong biofilm producers while 23% of them were not able to form biofilms. In this experiment, 18% and 42% of isolates were considered as moderate and weak biofilm-forming strains, respectively. In microtiter plate tests, 18% of strains were strong-biofilm producers and 25% of them were notable biofilm producers. In this assessment, 10% and 47% were considered as moderate and weak biofilm-forming isolates, respectively. The susceptibility tests, using microdilution method, confirmed that 92% of these isolates were resistant and 6.6% were susceptible to ciprofloxacin, although these results for imipenem were 68% and 24%, respectively.. It can be concluded that most of A. baumannii isolates can form biofilm in microtiter plate and tube. The results also verified that most of these isolates were resistant to ciprofloxacin and imipenem..

Nuts are one of the main consumed snacks worldwide and also have an important role among Iranian''s food habits. Natural contamination of nuts with aflatoxin is unavoidable and causes a special challenge for nuts safety and quality. The purpose of this research was to study the aflatoxin contamination in commercially-available nuts (pistachio, walnut and peanut) in the markets of Tabriz, Iran. Sixty two samples of 50 g salt-roasted peanuts and pistachios and 109 samples of 50 g pure pistachios, walnuts and peanuts were collected from different areas of local markets. After the initial preparations, ELISA test was performed for Aflatoxin measurement. Result showed that walnut (90%) and pure pistachio (2.3%) were the most and least contaminated samples, respectively. Mean aflatoxin contamination in the salt-roasted samples (19.88 ± 19.41 μg/kg) was significantly higher than the pure ones (6.51 ± 9.4 μg/kg) (P < 0.001). Respectively, 58.6%, 48.4% and 47.6% of salt-roasted pistachios, salt-roasted peanuts and walnut samples had aflatoxin contamination, which were more than the maximum tolerated level of Iran (MTL, 15 ppb). It was concluded that aflatoxin content of nuts should be monitored regularly to minimize the risk of aflatoxin hazard and ensure the food safety and quality.

Acinetobacter baumannii is an important human pathogen with increasing notoriety in the recent years, as a causative organism of drug resistant nosocomial infections, particularly in immunocompromised patients hospitalized in burn centers. The aim of this study was to determinate the role of efflux pump(s) in ciprofloxacin resistance of A. baumannii strains isolated from burn patients. Sixty-five A. baumannii strains were isolated from the burn patients hospitalized in Motahari Burns and Reconstruction Center in Tehran, Iran. Susceptibility test to ciprofloxacin was carried out by disk agar diffusion and agar dilution methods, according to the CLSI guidelines. Activity of the efflux system was evaluated using efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP). All Acinetobacter isolates were resistant to ciprofloxacin. The Minimum inhibitory concentration (MIC) range of ciprofloxacin in isolates was 4 to 128 μg/mL or greater. Moreover, susceptibility of strains to ciprofloxacin was highly increased in the presence of efflux pump inhibitor; So that, for 86.1% (56/65) of isolates, CCCP reduced the MIC by 2 to 64 folds. Our findings are suggestive that efflux-based system may play a role in fluoroquinolone resistance in A. baumannii isolates, affecting hospitalized patients. The ability of Acinetobacter to acquire resistance to these potent antimicrobials by the efflux pump mechanism is a concern. Therefore, new strategies are required in order to eliminate the efflux transport activity from the resistant bacteria causing nosocomial infections and provide more appropriate approaches for treatment and management of troubling infections.

Nowadays Candida albicans has become resistant to the toxic and expensive commercial anti-Candida drugs. Therefore, investigation for new anti-fungal agents is necessary.. The purpose of this survey was to investigate the in vitro anti-Candida activity of the hydroalcoholic extracts of Heracleum persicum fruit.. The plant ingredients were extracted using 80% ethanol and the extract was screened against 46 isolated pathogenic Candida species such as C. albicans, C. glabrata and C. tropicalis by agar well diffusion method.. The minimum inhibitory concentration (MIC) values at 24 and 48 hours were 0.625 - 20 µg/µL for C. albicans, 0.625 - 40 µg/µL for C. glabrata, and 5.0 - 20 µg/µL for C. tropicalis.. The results of this survey confirmed that tested plant extract had a potential anti-Candida activity. Hence, it is suggested to isolate and identify its active compounds in future..

Helicobacter pylori (H. pylori) is a spiral Gram negative bacteria that can transform to the coccoid form in adverse conditions.. The aim of this study was to determine the in vitro morphological and bactericidal effects of metronidazole, amoxicillin and clarithromycin on H. pylori.. The standard strain 26695 of H. pylori was cultured on Brucella agar (BA) and the minimum inhibitory concentrations (MICs) of three antibiotics were determined by E-test method. The bacteria were exposed to antibiotics at 1/2 MIC, MIC and 2X MIC concentrations in Brucella broth (BB). Induced coccoid forms were confirmed by Gram staining and light microscopy. The viability of cells as well as the susceptibility of viable coccoids to antibiotics were examined using the flow cytometry method.. All of the three antibiotics at sub-MIC induced coccoid forms. The highest rates of coccoids (> 90%) were induced at 0.008 μg/mL concentration (1/2 MIC) of amoxicillin, 72 hours postexposure. Metronidazole and clarithromycin with 1/2 MIC (0.5 and 0.125 µg/mL respectively) induced lower rates of coccoid forms (60% and 40% respectively). Potent bactericidal effects on coccoids were observed with Metronidazole at 2X MIC and clarithromycin at MIC (0.25 µg/mL) (80 - 90%). Amoxicillin with MIC and 2X MIC had no bactericidal effect on coccoid forms.. Despite the good in vitro bactericidal effect of amoxicillin on spiral forms of H. pylori, this antibiotic has little effect on induced coccoids that may develop after the inappropriate in vivo antibacterial treatment. Hence, for successful therapy, it is essential not only to eradicate the spiral forms, but to eliminate the viable coccoids..

Emergence of antimicrobial resistance toward a number of conventional antibiotics has triggered the search for antimicrobial agents from a variety of sources including the marine environment.. The aim of this study was to evaluate the antimicrobial potential of Holothuria leucospilota from Qeshm and Kharg Islands against some selected bacteria and fungi.. In this investigation, sea cucumbers from two coastal cities of Persian Gulf were collected in March and May 2011 and identified by the scale method according to the food and agriculture organization of the United Nations. Antibacterial activity of hydroalcoholic extracts of the body wall, cuvierian organs and coelomic fluid, methanol, chloroform, and n-hexane extracts of the body wall were evaluated by the spot test. In addition, their antifungal activity was assessed by the broth dilution method.. The displayed effect was microbiostatic at concentrations of 1000 and 2000 µg/mL rather than microbicidal. The highest activity of hydroalcoholic extracts was exhibited by body wall, cuvierian organs and coelomic fluid against Escherichia coli, Salmonella typhi, Staphylococcus aureus and Pseudomonas aeruginosa; Aspergillus niger, A. fumigatus, A. flavus and A. brasilensis. However, none of the methanol, chloroform and n-haxane extracts showed appreciable effects against Shigella dysenteriae, Proteus vulgaris, Bacillus cereus, S. epidermidis and Candida albicans. Moreover, cuvierian organs did not possess any antifungal potential.. Our data indicated that water-methanol extracts from the body wall of H. leucospilota possess antibacterial and antifungal activity. However, additional and in-depth studies are required to isolate and identify the active component(s)..

There is increased demand for improved disinfection methods due to microorganisms resistant to multiple antimicrobial agents. Numerous types of disinfectants are available with different properties; but the proper disinfectant must be carefully selected for any specific application to obtain the desired antimicrobial effect.. Antimicrobial effect of a commercial nanosilver product, NanoCid® L2000, against some foodborne pathogens was evaluated.. Minimum inhibitory concentrations (MIC) were determined by monitoring the growth of bacteria at 600 nm, after 24 hours incubation at 35°C. Minimum bactericidal concentrations (MBC) were determined based on 3 log decrease in the viable population of the pathogens after incubation of nutrient agar plates at 35°C for 24 hours. The required exposure time for 3 log reduction in the viable population of the tested pathogens was determined as the minimum exposure time for efficient bactericidal activity.. The MIC values of Ag NPs against tested pathogens were in the range of 3.12-6.25 µg/mL. While Listeria monocytogenes showed the MIC value of 6.25 µg/mL, Escherichia coli O157:H7, Salmonella typhimurium and Vibrio parahaemolyticus all showed the MIC values of 3.12 µg/mL. However, all the pathogens showed the same MBC value of 6.25 µg/mL. To obtain an efficient bactericidal activity against E. coli O157:H7 and S. typhimurium, the exposure time should be at least ca. 6 hours., while this time was ca. 5 hours for V. parahaemolyticus and ca. 7 hours for L. monocytogenes. Silver nanoparticles showed great antibacterial effectiveness on four important foodborne pathogens. Therefore, Ag NPs could be a good alternative for cleaning and disinfection of equipment and surfaces in food-related environments..

Nuts are one of the main consumed snacks worldwide and a significant component of Iranian’s diet. Natural contamination of nuts with fungus is unavoidable and is a major challenge to nuts safety and quality.. The purpose of this research was to study fungal contamination in commercially available nuts (pistachios, walnuts and peanuts) in the markets of Tabriz, Iran.. 100 samples of 50 gr roasted with salt peanuts and pistachios and 300 samples of 50 gr pure pistachios, walnuts and peanuts were collected from different areas of the local markets. After initial preparation, the samples were cultured on Sabouraud’s dextrose agar (SDA). 19 fungal isolates were identified.. The results show that Aspergillus niger was the predominant mold among pure (44%) and roasted with salt (14%) nuts (P < 0/001). In addition, percentage of mycotoxigenic fungal contamination was 18% for roasted with salt nuts and 11% for pure samples.. The overall results of the analysed samples showed that the rate of fungal contamination in pure samples was higher than roasted with salt ones (P < 0.005). Results of the current survey could be useful for minimizing fungal contamination and can educate people about the dangers of mold in nuts..

Malaria is a protozoal disease, transmitted to humans by female Anopheles mosquito bite. Plasmodium falciparum, compared to other kinds of Plasmodium, causes more severe malaria and is associated with a higher mortality rate. Annually, one to three million deaths occur due to malaria, especially by P. falciparum.. In this report, we introduce an Iranian patient suffering from P. falciparum. Peripheral blood smear for malaria parasites showed severe infection of P. falciparum, with 75 to 85 percent of red blood cells containing one to five parasites per cell. However, the patient revealed a fast response to treatment and a good prognosis, suggesting a high level of relative immunity in the patient. To confirm this hypothesis, we conducted a comparative study by comparing the rate of clinical response to treatment as well as the level of prognosis of our patient with similar patients from different regions around the world. These included some malaria cases (caused by P. falciparum) chosen from endemic and nonendemic regions, such as Africa, South Europe and Canada.. The findings revealed that generally, patients from endemic regions significantly show a greater response to treatment and also a better prognosis in comparison to the patients from nonendemic regions. These differences can plausibly be attributed to a high level of relative immunity in endemic regions. Consequently, we would strongly support the hypothesis that response to treatment and prognosis of malaria is a matter of patients’ living environment circumstances. In other words, people who live in endemic regions acquire a high relative immunity leading to a greater response to treatment and a better prognosis..

Due to the limitations of the classical methods to detect Coxiella burnetii, direct diagnosis of the pathogen using PCR techniques is still the preferable approach. However, false negative results owing to the presence of PCR inhibitors are troublesome.. In order to identify the inhibitors during PCR assay, an internal positive control (IPC) was designed based on 16SrRNA gene of C. burnetii.. In the current study, the initial and ending parts of the target gene in an external positive control plasmid (pTZ57R/T-16S) amplified using internal primers which had a BglII restriction site on the 5´ends. Both PCR products (fragments 1 and 2) were cloned into pTZ57R/T vector. Following BglII enzyme digestion, the two obtained linear plasmids were ligated. The ligation product was transformed into Escherichia coli Top10Fʹ. Screening of the desired recombinant clone was carried out using colony PCR.. The size of the PCR product was equal to the sum of the first and second fragments. Sequencing confirmed the presence of the desire insert (IPC sequence) in recombinant plasmid. Consequently, the IPC fragment was longer than the target gene while both ends had similar attachments to the same primer pair.. The results showed that direct fusion of the recombinant plasmids containing the initial and ending parts of the target gene are simple and cost-effective techniques for increasing the length of the fragment and constructing IPC.

Pseudomonas aeruginosa is a leading cause of nosocomial infections worldwide. Resistance of P. aeruginosa strains to the broad-spectrum cephalosporins may be caused by extended-spectrum β-lactamases (ESBLs).. The aim of this study was to determine the antimicrobial resistance patterns and prevalence of PER-1 and VEB-1 type genes among ESBL producing strains of P. aeruginosa.. A total of 106 P. aeruginosa isolates were collected from two university hospitals in Hamadan, Iran, during a7-month study (2009). The antimicrobial susceptibility of isolates was determined by disc diffusion method and interpreted according to the clinical and laboratory standards institute (CLSI) recommendations. Production of ESBL was determined by combined disk test and presence of PER-1 and VEB-1 type ESBL genes was identified by PCR.. The resistance against broad-spectrum cephalosporins and monobactames were: cefepime (97%), cefotaxime (92.5%) ceftazidime (51%), and aztreonam (27%). Ciprofloxacin (91.5%), imipenem (84.9%) and meropenem (82.1%) were the most effective anti-pseudomonas agents in this study. The results revealed that 88.7% of the isolates were multidrug resistant, 58.25% of those were ESBL positive. Sixteen (26.6%), 9 (15%) and 3 (5%) strains among ESBL-producing strains contained blaPER-1, blaVEB and blaPER-1-blaVEB, respectively.. This study highlighted the need to establish antimicrobial resistance surveillance networks for P. aeruginosa to determine the appropriate empirical treatment regimens. The high prevalence of multidrug resistance and production of ESBLs in P. aeruginosa isolates confirms the necessity of protocols considering these issues in the hospitals.

Urinary tract infections (UTIs) are important causes of morbidity and mortality in patients with spinal cord injury and 22% of patients with acute spinal cord injury develop UTI during the first 50 days.. The aim of this study was to determine the prevalence, etiologic agents and risk factors for asymptomatic bacteriuria and symptomatic urinary tract infections in patients with spinal cord injury..Patients and This was a prospective investigation of spinal cord injury patients with asymptomatic bacteriuria and symptomatic urinary tract infections in Baskent University Medical Faculty Ayas Rehabilitation Center and Ankara Physical Therapy and Rehabilitation Center between January 2008 and December 2010. The demographic status, clinical and laboratory findings of 93 patients with spinal cord injury were analyzed in order to determine the risk factors for asymptomatic or symptomatic bacteriuria. Sixty three (67.7%) of 93 patients had asymptomatic bacteriuria and 21 (22.6%) had symptomatic urinary tract infection. Assessment of the frequency of urinary bladder emptying methods revealed that 57 (61.3%) of 93 patients employed permanent catheters and 24 (25.8%) employed clean intermittent catheterization. One hundred and thirty-five (48.0%) of 281 strains isolated form asymptomatic bacteriuria attacks and 16 (66.6%) of 24 strains isolated from symptomatic urinary tract infection attacks, totaling 151 strains, had multidrug resistance (P > 0.05). One hundred (70.4%) of 142 Escherichia coli strains and 19 (34.5%) of 55 Klebsiella spp strains proliferated in patients with asymptomatic bacteriuria; 8 (80%) of 10 E. coli strains and 4 (80%) of 5 Klebsiella spp. strains were multidrug resistant.. The most common infectious episode among spinal cord injury patients was found to be urinary tract ınfection. E. coli was the most common microorganism isolated from urine samples. Antibiotic use in the previous 2 weeks or 3 months, hospitalization during the last one-year and previous diagnosis of urinary tract ınfection were the risk factors identified for the development of infections with multi-drug resistant isolates. Urinary catheterization was found to be the only independent risk factor contributing to symptomatic urinary tract infection..

Cassia fistula, is a flowering plant and a member of Fabaceae family. Its leaves are compound of 4 - 8 pairs of opposite leaflets. There are many Cassia species around the world which are used in herbal medicine.. This study was designed to examine in vitro anti-bacterial activity of methanolic and ethanolic extracts of C. fistula native to Khuzestan, Iran.. The microbial inhibitory effect of methanolic and ethanolic extracts of C. fistula was tested on 3 Gram positive: Bacillus cereus, Staphylococcus aureus and S. epidermidis and 5 Gram negative: Salmonella Typhi, Kelebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis bacterial species using disc diffusion method at various concentrations. The minimum inhibitory and bactericidal concentrations (MIC and MBC) were measured by the tube dilution assay.. The extract of C. fistula was effective against B. cereus, S. aureus, S. epidermidis, E. coli and K. pneumoniae. The most susceptible microorganisms to ethanolic and methanolic extracts were E. coli and K. pneumoniae, respectively. Also B. cereus and S. aureus showed the least sensitivity to ethanolic and methanolic extracts, respectively. The MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) of ethanolic extracts against S. aureus, E. coli, S. epidermidis and K. pneumoniae were also determined.. With respect to the obtained results and regarding to the daily increase of the resistant microbial strains to the commercial antibiotics, it can be concluded that these extracts can be proper candidates of antibacterial substance against pathogenic bacterial species especially S. aureus, E. coli, K. pneumoniae and S. epidermidis..

The number of reported cases, infected with carbepenem resistant Acinetobacter baumannii (CRAb) and multi-drug resistant (MDR) Acinetobacter species had gradually increased in most PLA general hospital wards from April to June in 2007.. We have described the investigation of an outbreak of CRAb and MDR Acinetobacter in PLA general hospital, Beijing. The prospective and retrospective findings were identified and analyzed to study the infection causes.. A. baumannii samples were collected from the patients and environment in each hospital unit. The onset times were recorded according to their case information. All samples were characterized by genotype and compared using pulsed-field gel electrophoresis (PFGE). The microorganism susceptibility was tested using the in vitro minimal inhibitory concentration (MIC) breakpoints method.. A total of 69 A. baumannii strains were successfully isolated from 53 patients. About 89.1% of them were resistant to ampicillin and 89.2% to cefotaxime and 75.4% to all standard antibiotics. PFGE analysis revealed that nine of the isolates had unique clones and the epidemic clone types were A, B and C.. The A. baumannii outbreak, was caused by MDR A. baumannii. The strains had widely spread among 12 departments especially in surgical intensive care unit (SICU), emergency intensive care unit (EICU) and the department of respiratory disease. The outbreak was more likely caused by the A. baumannii infected or carrier patients and EICU was its origin．.