Evaluation of semisolid agar screening tests for determining fluconazole and amphotericin B susceptibilities of Candida strains by using three different media

The susceptibilities of 164 Candida isolates against fluconazole and amphotericin B were determined by semisolid agar screening tests and the microdilution method according to NCCLS M27-A standards. The semisolid agar screening tests were performed with three different media containing 0.5% agar and 2, 8, and 40 microg/ml of fluconazole or 0.5 and 2.0 microg/ml of amphotericin B. These media were MOPS buffered RPMI 1640, brain-heart infusion and 1/3 diluted Sabouraud dextrose agar. The results of both methods were interpreted as susceptible, dose dependent susceptible and resistant for fluconazole and susceptible and resistant for amphotericin B. The agreement rates of semisolid agar screening tests using RPMI 1640, brain-heart infusion and Sabouraud dextrose media with the reference microdilution method were found to be 71.4%, 51.2%, and 57.3% for fluconazole and 79.3%, 53.7%, and 56.7% for amphotericin B, respectively. Overall, we conclude that semisolid agar screening tests using RPMI 1640 can be used for determining the susceptibilities of Candida isolates against fluconazole and amphotericin B in clinical microbiology laboratories.

Recovery period of the bladder after exposure to soluble virulence factor produced by Escherichia coli

OBJECTIVES

This study was designed to determine the time interval required for the recovery of the bladder after exposure to soluble virulence factor (SVF) in an animal model. In addition, we aimed to determine the changes in the epithelium during the recovery period.

METHODS

A total of 46 male New Zealand rabbits were used in this study. Sterile human urine was infected with Escherichia coli type O6 to obtain supernatant, which would contain SVF, but no bacteria. Rabbits were assigned to one of three groups comprising the supernatant urine group (SUG) and controls, respectively. Sterile human urine and supernatant urine were instilled to controls and SUG, respectively. Bacterial inoculation with E. coli was performed 1, 24 and 72 h after initial instillation. Histopathologic and microbiologic analyses were performed on these animals.

RESULTS

In SUG bacterial colonization was significantly higher than in controls 1 and 24 h after exposure to supernatant. Histopathologic analysis confirmed this finding. Histologic changes were most pronounced 1 hour after instillation of supernatant. A moderate degree of recovery was noted at 24 h, and complete recovery was seen at 72 h.

CONCLUSION

Bacterial growth is potentiated by SVF-induced impaired bladder mucosa until the repairing process has been completed. During this time interval, SVF enables the colonization and growth of E. coli and other bacterium species that may result in sustained bacterial presence and recurrent infection.

Use of chromogenic tube and methyl blue-sabouraud agar for the identification of Candida albicans strains

This study was performed to investigate the use of chromogenic tube and methyl blue-Sabouraud agar for the presumptive identification of Candida albicans. 124 clinical isolates, including 111 C.albicans and 13 Candida spp strains, which had been identified by morphology on cornmeal tween 80 agar and Vitek automated identification system, were included. Three different identification procedures, a) germ tube test, b) chromogenic tube test by using CHROMagar Candida and c) methyl blue-Sabouraud agar test, were performed to the strains. 88 of 111 (79.3%) C.albicans strains were detected to be positive by germ tube test. 87 (78.4%), 97 (87.4%) and 102 (91.9%) of these isolates were identified as C.albicans by chromogenic tube test after 2, 8 and 24 hours of incubation, respectively. 88 (79.3%), 92 (82.9%) and 88 (79.3%) of the isolates were correctly identified as C.albicans by methyl blue-Sabouraud agar test after 2, 8 and 24 hours of incubation, respectively. The sensitivity and specificity values were found to be 79.3 and 69.2 for the germ tube test. These values ranged between 78.4-91.9% and 69.2-76.9% for chromogenic tube test and 79.3-82.9% and 76.9-84.6% for methyl blue-Sabouraud agar depending on the incubation period. It can be concluded that the use of chromogenic tube and methyl blue-Sabouraud agar are rapid, simple and objective methods for the identification of C.albicans strains.

Disk diffusion method for fluconazole susceptibility testing of Candida albicans strains

This study evaluated the usefulness of the disk diffusion method by using different media for the susceptibility testing of fluconazole against Candida albicans strains. The susceptibility of 108 clinical isolates of C. albicans against fluconazole were determined by microdilution and disk diffusion methods by using RPMI 1640 agar and 25 microg disks. 93 of these isolates were also tested by disk diffusion technique on four different media (yeast nitrogen base agar, Sabouraud dextrose agar, Mueller Hinton agar and Mueller Hinton methylene blue agar). The results of the microdilution method were evaluated visually and optically. The disk diffusion results were determined after 24 and 48 hours of incubation. When the 24-hour zone diameters were compared to the minimal inhibitory concentrations determined visually and optically, the best results were obtained for RPMI 1640 agar and yeast nitrogen base agar. The correlation coefficients were r=-0.34, -0.41 and r=-0.33, -0.32 for the first and second media, respectively. The best values (r=-0.29, -0.39) were obtained for Mueller Hinton methylene blue agar when the 48-hour zone diameters were considered. Agreement between the disk diffusion and microdilution methods was best for RPMI 1640, yeast nitrogen base and Mueller Hinton methylene blue agar after 24 hours of incubation (87-89%, 88-90%, 93-96%, respectively) and for Mueller Hinton methylene blue agar after 48 hours of incubation (89-96%). Disk diffusion method using RPMI 1640, yeast nitrogen base and Mueller Hinton methylene blue agar appears to be a useful, rapid and reliable screening technique for testing the susceptibility of C. albicans strains to fluconazole.

The comparison of the efficacy of fluticasone propionate with cetirizine in perennial allergic rhinitis

BACKGROUND

Allergic rhinitis is an IgE mediated hypersensitivity reaction of the nasal mucosa characterised by nasal discharge, obstruction, and pruritus.

PATIENTS AND METHODS

In this study, 43 patients with perenneal allergic rhinitis were enrolled in order to compare the efficacy of Fluticasone Propionate (FP), a corticosteroid nasal spray, with Cetirizine, a systemic oral antihistaminic preparation, which is supposed to have nonsteroidal antiinflammatory activity. Cetirizine (10 mg daily as a single dose) was administered to 22 patient for 45 days. On the other hand, FP (400 micrograms/day) was administered into each nostril twice a day in the remaining 21 patients for 45 days. Skin test was obtained from each patient before therapy. Total eosinophil count, eosinophil count in nasal smear, electrorhinomanometric investigation, PGE2 and ratio of LTC4 to LTD4 both in the serum and in the nasal secretions were determined before and after therapy. In addition, percentage of eosinophils, and mast cells count in the biopsy specimens taken from anterior edge of middle choncha were evaluated before and after therapy, and than the results were graded for each patients.

RESULTS

When we compared the eosinophil count in nasal smear, eosinophil percentage and total eosinophil parameters between two groups, it was shown that FP was more effective than Cetirizine. On the other hand, when we compared the ratio of LTC4 to LTD4 in serum and nasal smear, level of PGE2 and mast cell and nasal airway resistance measured by ERM, there were non statistical difference between two groups.

CONCLUSION

These results suggest that FP and Cetirizine may be used alternatively in case of an adverse reaction to any of them.

Antimicrobial resistance of gram-negative isolates from intensive care units in Turkey: comparison to previous three years

Resistance rates to selected antibiotics of gram-negative bacteria isolated from intensive care units (ICU) of 16 Turkish hospitals during 1998 were evaluated and compared to data from the previous 3 years. Antibiotic susceptibilities to imipenem, ceftazidime, ceftazidime-clavulanate, cefoperazone-sulbactam, ceftriaxone, cefepime, cefodizime, cefuroxime, piperacillin-tazobactam, ticarcillin-clavulanate, gentamicin, amikacin and ciprofloxacin were determined by Etest. A total of 1,404 isolates from 1,060 patients were collected, mainly from urinary and respiratory tracts. As in the previous 3 years, Pseudomonas spp. was the most frequently isolated gram-negative species (29.7%), followed by Escherichia coli, Acinetobacter and Klebsiella spp. Imipenem was the most active in vitro agent (73.4% susceptible), followed by ciprofloxacin (60.6%), cefoperazone-sulbactam (58.7%), cefepime (56.7%), piperacillin-tazobactam (55.0%) and amikacin (54.7%). In 1996, a decline in susceptibility rates of all antibiotics was evident. With the exception of imipenem, resistance to which remained stable, rates somewhat increased in 1997. In 1998, susceptibility to imipenem and cefepime remained stable, amikacin resistance tended to increase and susceptibility rates to other antibacterials showed a favorable increase. These results may in part be due to the implementation of a surveillance program and increased understanding of the magnitude of the resistance problem.

Surveillance of antimicrobial resistance among gram-negative isolates from intensive care units in eight hospitals in Turkey

With the participation of eight major reference hospitals in Turkey, 749 aerobic Gram-negative isolates obtained from 473 intensive care patients in 1997 were tested for their susceptibility to 13 commonly employed antibacterial agents. The frequency with which species were isolated and resistance rates were compared with data from the previous 2 years. Imipenem was the most active agent against the majority of isolates (75%), followed by ciprofloxacin, cefepime and amikacin. The per cent susceptibility to all antibiotics declined from 1995 to 1996. With the exception of imipenem, for which there was no change in resistance, the per cent susceptibility somewhat increased in 1997. However, it was still lower than in 1995.

A surveillance study of antimicrobial resistance of gram-negative bacteria isolated from intensive care units in eight hospitals in Turkey

This study was carried out with the participation of eight hospitals in Turkey to determine the frequency of gram-negative bacteria isolated in intensive care units (ICU) and to compare their resistance rates to selected antibiotics. Aerobic gram-negative bacteria isolated from ICUs during 1996 were studied. Antibiotic susceptibilities to imipenem, ceftazidime, ceftazidime-clavulanate, ceftriaxone, cefotaxime, cefepime, cefodizime, cefuroxime, piperacillin/tazobactam, amoxycillin-clavulanate, gentamicin, amikacin and ciprofloxacin were determined by Etest. A total of 748 isolates were obtained from 547 patients. The majority of organisms were isolated from the respiratory (38.8%) and urinary tracts (30.9%). Pseudomonas spp. were the most frequently isolated gram-negative species (26.8%), followed by Klebsiella spp. (26.2%). Escherichia coli, Acinetobacter spp. and Enterobacter spp. were the other commonly isolated organisms. High resistance rates were observed for all antibiotics studied. Imipenem appeared to be the most active agent against the majority of isolates. Although resistance rates exceeded 50%, ciprofloxacin, cefepime and amikacin were found to be relatively effective. Extended-spectrum beta-lactamase (ESBL) production appeared to be a major mechanism of resistance to beta-lactam antibiotics. In contrast to ceftazidime-clavulanate, piperacillin/tazobactam showed poor activity against organisms thought to produce ESBL, suggesting the presence of an enzyme resistant to tazobactam action. This study has yielded high rates of resistance in aerobic gram-negative isolates from ICUs in Turkey. High resistance rates to all the other antibacterials studied leave imipenem as the only reliable agent for the empirical treatment of ICU infections in Turkey.

Ureaplasma urealyticum-induced urinary tract stones in rats

This study investigated the possible role of Ureaplasma urealyticum, which is predominantly located in the urogenital tract, in the formation of infectious stones. A standardized Ureaplasma urealyticum broth culture isolated from a human urogenital specimen was inoculated into the renal medulla of five male rats (Rattus norvegicus L., Wistar C, weighing 170 +/- 10 g) and the same amount of culture media was used for five identical control rats. Five days after the inoculation, the rats were killed and fresh preparations from the bladders and the inoculated kidneys of both groups were prepared. At the same time biochemical and histopathological analysis of the contents of the bladders and the inoculated kidneys of both groups was performed. Crystal formation within the bladders of the inoculated rats was demonstrated and biochemical analysis of the crystals showed calcium, magnesium and phosphate, which indicated the existence of infection-induced crystals. These findings were absent in the control rats. The role of Ureaplasma in the production of urinary tract infectious stones was thus demonstrated in vivo.

Synthesis of ethanone derived from 2-benzoxazolinones and their antimicrobial activities

A number of 3-(4-substituted benzoyl methyl)-2-benzoxazolinones have been synthesized by reacting with 2-benzoxazolinone and 4-substitutet phenacyl bromide in ethanol. Their structures were confirmed by microanalysis, IR and NMR spectral analysis. Possible antimicrobial activity of the compounds was investigated by tube dilution and paper disc techniques using bacteria (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Staphylococcus faecalis RSKK 10541) and yeast-like fungi (Candida parapsilosis, Candida albicans, Candida pseudotropicalis, Candida stellaoidea). Among the compounds tested 3-(4-bromo benzoylmethyl)-5-chloro-2-benzoxazolinone (compound 4) and 3-(4-nitro benzoyl methyl)-5-chloro-2-benzoxazolinone (compound 6) showed the most favorable activity.

Synthesis and antimicrobial activities of some dithiocarbamate derivatives of Kojic acid

The synthesis of new some dithiocarbamate derivatives of kojic acid are reported. The structures of these compounds are supported by their IR and 1H-NMR spectra, as well as by elemental analysis. The new compounds were tested for their antimicrobial activities.

Concentration and avidity of anti-tetanus antibodies in mother-infant pairs: relation to immunization time

The concentration and avidity of anti-tetanus antibodies in two groups of mother-infant pairs were compared. Mothers immunized during pregnancy and their newborns (group A) had significantly higher antibody concentrations than mothers immunized at least a year before their last pregnancy and their newborns (group B) as measured by an indirect enzyme immunoassay (EIA) procedure. Antibody avidity of samples was measured by an inhibition EIA technique and urea denaturation test. Although antibody avidity was higher in group B, the differences were not significant. These findings may represent a secondary antibody response to a protein antigen, when considering that all mothers in both groups had received a primary tetanus vaccination during childhood. In mothers with a history of primary tetanus immunization, a single booster dose of tetanus toxoid during pregnancy is enough to induce protective levels of antibodies with reasonably high avidity in both mother and newborn.

Synthesis and biological activities of some 3,6-disubstituted thiazolo[3,2-b][1,2,4]triazoles

Some new 2,3-dihydro-3-hydroxy-6-phenyl-3-(4-substituted- (phenylthiazolo[3,2-b][1,2,4]triazole derivatives were synthesized as antifungal agents. After their structures were confirmed by microanalysis and IR and NMR spectral analysis, their antifungal activities against Candida albicans, Candida parapsilosis, Candida stellatoidea, and Candida pseudotropicalis were investigated. Contrary to our expectations, all proved to have poor antifungal activities. Because 2,4-dihydro-3H-1,2,4-triazol-3-ones are a new class of anticonvulsant agents, a series of thiazolo[3,2-b][1,2,4]triazoles was evaluated for anticonvulsant activity and observed as potential anticonvulsant candidates. All compounds examined exhibited activity against both maximal electroshock and pentylene tetrazole-induced seizures in mice.

Cervicofacial actinomycosis (a case report)

Actinomycosis is now a very uncommonly diagnosed human disease. Major medical centers report approximately one case a year. The pathogenesis of actinomycosis is unclear, but trauma provides a portal of entry. The cervicofacial form is the most common and usually appears as a chronic swelling with one or more draining sinus tracts. For treatment, penicillin in high doses is suggested. This case report presents a case of cervicofacial actinomycosis in a 14 year old boy which was misdiagnosed for a long time and the treatment of the disease with mezlocillin, a new antibiotic in the treatment of actinomycosis.

[Escherichia coli hemolysin: secretion kinetics and cytotoxic effect]

Escherichia coli hemolysin is one of the most important virulence determinants for uropathogenic strains. Hemolysin is cytotoxic to renal proximal tubular epithelial cells and leukocytes. It also causes the release of various mediators of inflammation and enzymes from leukocytes, thereby enhances the tissue damage to renal epithelium. The secretion kinetics of hemolysin was studied and found to be maximally secreted by an active process during logarithmic phase. The cytotoxic effect of the hemolysin was shown using Vero cells and by measuring Lactate Dehydrogenase activity in culture supernatants. The hemolytic strain showed significant cell lysis in comparison to non-hemolytic strain.

[The effect of calcium ions on the activation of Escherichia coli hemolysin]

The calcium requirement for hemolytic activity Escherichia coli hemolysin is controversial. Thus, we aimed to study the calcium-dependent and independent hemolytic activity in an in vitro system. It was found that the free calcium in the cultivation medium might activate the hemolysin and once activated the hemolytic activity could not be inhibited by calcium chelator, EGTA. However, when the free calcium in the medium was chelated by EGTA before the inoculation of bacteria, the hemolytic activity was found to be almost entirely dependent upon the exogenous calcium supply to the test system. We also obtained some evidence showing that the calcium ions could take part in stabilization of this protein.

Synthesis and antipseudomonal activities of some ofloxacin esters as prodrugs

Three new ofloxacin esters have been synthesized as prodrug by the reaction of ofloxacin (CAS 82419-36-1) with chloromethylacetate, 1-chloroethylacetate and 1-chloroethylethylcarbonate in acetonitrile. The structures of the compounds have been elucidated by UV, IR, 1H-NMR, Mass spectra and elementary analysis. In vitro activities of these compounds against clinical isolates of various Pseudomonas aeruginosa species have been determined by microtiter tube dilution method, and octanol/water partition coefficients and pH dependent hydrolysis rates have been investigated in comparison with ofloxacin.

[The role of Candida albicans in denture stomatitis]

Denture stomatitis is a clinical inflammatory picture that is seen at oral mucosa of the upper chin of patients who use removable dentures. There are various reasons of denture stomatitis. In order to detect the presence rate of C. albicans on lesions as the most important factor and the factors which effect this situation, 41 patients (31 with denture stomatitis and 10 as controls) were chosen. The smears obtained from the hard palate of the patients were microbiologically investigated. C. albicans was found to be the causative agent in 35.4% of the cultures which have shown growth. The relationship of sex, age and the period of denture usage was investigated in these cases.

Synthesis and antimicrobial activities of some new tetrahydro-2H-1,3,5-thiadiazine-2-thione derivatives of cephalexin

In this study, compounds with a 7-[2-(dihydro-5-substituted 6-thioxo-2H-1,3,5-thiadiazine-3[4H]-yl)-2-phenyl]acetamido-3 -methyl-3- cephem-4-carboxylic acid structure were synthesized by reacting cephalexin monohydrate with formaldehyde and dithiocarbamic acid salts prepared from some primary amines. The structure of the compounds was confirmed by spectral data and elementary analysis. The antimicrobial activities of the compounds were investigated against some bacteria (Staphylococcus aureus, Streptococcus faecalis, Escherichia coli and Pseudomonas aeruginosa) and some Candida sp. (C. albicans, C. parapsilosis, C. stellatoidea and C. pseudotropicalis) by using tube dilution method. In microbiological studies, cephalexin monohydrate was used as reference standard. Both compounds were synthesized and cephalexin monohydrate was found ineffective against S. faecalis and P. aeruginosa in the concentrations studied. While most of the compounds showed bacteriostatic activity against S. aureus, compounds 1, 3 and 7 showed the same activity against E. coli. On the other hand, compound 3, 5, 6, 7 and 10 showed anticandidal activity, whereas cephalexin monohydrate was not active against any Candida sp. Compound 11 was found effective against C. stellatoidea and C. pseudotropicalis.

[Microbiological analysis of well water samples in the rural areas near Ankara]

The water from wells and running water in different rural parts of Ankara were analyzed microbiologically with the thought in mind that the use of unhealthy well water could cause infections, as shown in other cities. We found that of the 50 running water samples all (100%) were drinkable from the microbiological point of view regard to coliform bacteria and total germ count, while only 20 of the 150 well water samples (13.3%) met these standards. It was pointed out by the users that chlorination was carried out in only 22 of the wells (14.6%) and only irregularly; no coliform bacteria were found in water samples from these wells. In 117 well water samples (78%) 120 coliform bacteria strains were isolated, of these 80 were E. coli, 27 Enterobacter and 13 Citrobacter. All samples were analyzed for Giardia intestinalis cysts but found to be negative.

[The prevalence of intestinal parasites in the students of two primary schools in Ankara]

Four hundred stool samples obtained from two different primary school students were examined for intestinal parasite. Cellophane tape technique was also applied in order to detect the Enterobiasis incidence. It has been observed that the parasite incidence were 13.5% in TED College Students whereas 30.5% in the Incesu Primary School. It has been also concluded that the highest infection rate was connected with two parasites, namely Giardia intestinalis (11.5%) and Enterobius vermicularis (8%).

[Bacterial etiology of eye infections]

The purpose of this study was to determine the etiologic agents in bacterial ocular infections, their antibiotic sensitivities and the most suitable conditions for the microbiological diagnosis, using several methods. 200 patients who were diagnosed to have bacterial conjuntivitis (111 cases), corneal ulcers (39 cases), dacryocystitis (34 cases) or infections of the eyelids (16 cases) at the ophthalmology department of our university were taken as the patient group and there were 100 normal people in the control group. The frequency and species of bacteria isolated from both groups are similar to those in the literature. In cases of conjunctivitis, the results of the direct smears were parallel to the results obtained by cultures in 8.2% of the cases. The percentage of growth was higher when the specimen was inoculated immediately in the clinic compared to the results obtained by inoculations which were performed in the laboratory. According to the results of the antibiotic sensitivity tests, chloramphenicol should take the first place among the antibiotics which are in general use for gr (+) and gr (-) bacteria, and tetracyclines should take the second place while waiting for the results of the cultures.

[Aspergilli and chronic lung diseases]

In this study, mycological examinations of morning sputum of patients with chronic bronchitis and bronchial asthma has been performed. Specimens were also examined from patients with lobar pneumonia as a control. A fumigatus and A. niger has been isolated from patients chronic bronchitis in frequency of 4.5% and 0.8% respectively. These 2 fungi has also been isolated from patients with bronchial asthma in frequency of 24.5% (A. fumigatus) and 2.4% (A. niger). The frequency of isolation of A. fumigatus has been found statistically significant between these two groups of patients (p less than 0.05). No isolation of Aspergillus spp. has been noted in control patients specimens.

[Indoor and outdoor fungal flora of Ankara]

The variation of atmospheic fungal flora of Ankara were studied. Beside this the fungal floras of indoor and outdoor air were compared. In outdoor air Penicillium was detected most, followed by Cladosporium, Alternaria, Helminthosporium, Aspergillus, Rhizopus and Mucor. In the indoor air the same fungi were detected. However, Penicillium and Aspergillus were found more compared with outdoor findings. Since in many parts of Ankara (Yenişehir, Cebeci, Küçükesat, Bahçelievler, Aydinlikevler), different fungi are found in indoor and outdoor air and many of them are the etiologic agents of allegic diseases, doctors have to make fungal cultures from the indoor and outdoor air of living and working buildings in order to find the source of allergic diseases.

[The fungi causing superficial mycoses found in and around Ankara]

In this research the agents in the specimens taken from 400 patients whose diagnosis were superficial cutaneous infection were investigated. The specimens were collected from the Dermatology Clinics of Hacettepe Hospital and Numune Hospital. As a result of our experiments we isolated T. mentagrophytes, T. rubrum, E. floccosum, T. schoenleini, M. canis, T. violaceum, M. audouini, M. gypseum. It is also established that beside C. albicans, other Candida species are also the causes of cutaneous fungus infection.

[The mycological and bacteriological flora of cigarettes and its relation to human throat culture and inhalation air]

In our research we studied the mycological and bacteriological flora of both filtered and non-filtered Turkish cigarettes. We also studied by bacteriologic and mycologic methods, the specimens taken from throath of healthy people of varied ages who smoke and who do not smoke, and the flora of inhalation air from different area.