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.

Effect of subminimal inhibitory concentrations of gentamicin, penicillin, trimethoprim-sulfamethoxazole on adherence of uropathogenic Escherichia coli strains.

Evaluating the adherence factor of uropathogenic Escherichia coli is important for assessing the relative efficiency of antimicrobials when used at sub-minimal inhibitory concentration (sub-MICs). The microdilution method was used to determine the MICs of gentamicin, trimethoprim-sulfamethaxozole and penicillin. Then the efficacy of antimicrobial sub-MICs was determined by hemagglutination and adherence assays. Instead of showing nearly the same MICs, gentamicin had nearly twice the activity of trimethoprim-sulfamethaxozole. Gentamicin, as a "long acting" agent, can be accepted as being more effective than trimethoprim-sulfamethaxozole or penicillin, especially at sub-MICs, against adherence factors of uropathogenic E. coli, and can be used as monotherapy for urinary tract infections.

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.

Comparison of minimum inhibitory concentration values for fluoroquinolones against Escherichia coli causing urinary tract infection in both hospitalized patients and outpatients.

OBJECTIVE: To determine the resistance among Escherichia coli isolates causing urinary tract infections in hospitalized patients and outpatients. METHODS: This study was carried out in the Department of Microbiology, Dokuz Eylul University, Medical Faculty Hospital, Inciralti, Ismir, Turkey, from February 1997 through to June 1998. A total of 300 Escherichia coli strains were isolated from urine specimens of 111 hospitalized and 189 elderly outpatients (more than 20 years of age). We determined the minimum inhibitory concentrations of the test drugs nalidixic acid, pefloxacin, ofloxacin, norfloxacin and ciprofloxacin by the microdilution method, recommended by the National Committee for Clinical Laboratory Standards. RESULTS: Minimum inhibitory concentrations(50) and minimum inhibitory concentrations(90) values of strains tested against fluoroquinolones, pefloxacin and nalidixic acid were the same for strains isolated from hospitalized and outpatients (0.125 microg/ml outpatients (0.03 microg/ml). Twenty-six (9%) of 300 Escherichia coli strains were resistant to all drugs used. Twenty (77%) of these 26 strains were isolated from hospitalized patients. We found that the resistance to nalidixic acid is much higher than other fluoroquinolones. At the same time, the resistance in the strains that were isolated from hospitalized patients is again higher than outpatient strains (46%). CONCLUSION: Resistance among Escherichia coli isolates from patients to quinolones used in the treatment of urinary tract infections was rare during this period. Our study, like many other reports showed the increased resistance to fluoroquinolones for clinical isolates. However the appearance of multi resistant clones and the elevated prevalence of quinolones resistance in the hospital studied are warning signals for an increase in resistant strains as seen in many other countries. Therefore, it is important for physicians to use fluoroquinolones carefully so as to prevent, or delay, the emergence of resistant strains.

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.

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.

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 comparision of the efficacy of fluticasone propinate with cetirizine in perenneal allergic rhinitis

Background: allergic rhinitis is an IgE mediated hypersensitivity reaction of the nasal mucosa characterised by nasal discharg, 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, wich is suposed 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 mg/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 (AU)

Fundamento: la rinitis alérgica es una reacción de hipersensibilidad de la mucosa nasal, mediada por IgE, y caracterizada por secreción, obstrucción y prurito nasal.Pacientes y métodos: en este estudio se incluyeron 43 pacientes con rinitis alérgica perenne con el objetivo de comparar la eficacia de propionato de fluticasona (PF), un corticoide administrado en nebulización nasal, con cetiricina, un antihistamínico sistémico administrado por vía oral, que supuestamente carece de actividad antiinflamatoria no esteroide. A 22 pacientes se les administró cetirizina (10 mg/día en una sola dosis) durante 45 días. A los 21 pacientes restantes se aplicó PF (400 g/día) 2 veces al día en cada ventana nasal durante 45 días.Antes del tratamiento se efectuaron pruebas cutáneas a todos los pacientes. Antes y después del tratamiento se hicieron: recuentos de eosinófilos en sangre y frotis nasal; en suero y secreción nasal se determinaron PGE2 y la relación LTC4/LTD4, y además se realizó estudio electrorrinomanométrico.Además, antes y después del tratamiento, se evaluaron el porcentaje de eosinófilos y el recuento de mastocitos en las biopsias obtenidas a partir del borde anterior del cornete medio.Resultados: cuando comparamos el recuento de eosinófilos en el frotis nasal, porcentaje de eosinófilos y recuento total de eosinófilos entre ambos grupos, se puso de manifiesto que PF fue más eficaz que cetiricina. Por otra parte, cuando comparamos el cociente LTC4:LTD4 en suero y frotis nasal, valores de PGE2 y recuento de mastocitos y la resistencia de las vías respiratorias nasales determinadas mediante ERM, no se detectaron diferencias estadísticamente significativas entre ambos grupos.Conclusión: los resultados del presente estudio demuestran que ambos fármacos pueden utilizarse alternativamente en caso de reacciones adversas a cualquiera de ellos (AU)

Vancomycin-resistant enterococci in neonates.

Fecal-oral transmission of vancomycin-resistant strains of Enterococci (VRE), which colonize the human gastrointestinal tract, has led to nosocomial epidemics in recent years. The aim of this study was to establish the incidence and associated factors of fecal colonization with VRE in neonates. In our hospital 110 rectal swab specimens collected in the neonatal intensive care unit (NICU) were examined for VRE. For comparison, rectal swabs collected from 42 healthy neonates on the obstetrics ward were also analyzed. Of the NICU patients, 8 had VRE MICs of 8-64 microg/ml for vancomycin and 2-32 microg/ml for teicoplanin, whereas none of the healthy newborns, had VRE (p < 0.05). All patients positive for VRE had factors known to be associated with VRE carriage, such as low birth weight or long-term antibiotic therapy.

Aspergillus niger infection of exenterated orbit.

PURPOSE: To present two immunocompetent patients with Aspergillus niger infection of the exenterated orbit. METHODS: Case reports. RESULTS: The patients were treated with oral itraconazole and socket irrigation with amphotericin B. The sockets cleared completely; no growth was observed on reculturing. CONCLUSIONS: A niger infection of an exenterated socket can be effectively treated with oral itraconazole and topical amphotericin B in immunocompetent patients.

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.

Beta-lactamase patterns and betalactam/clavulanic acid resistance in Escherichia coli isolated from fecal samples from healthy volunteers.

Fecal specimens from 50 healthy volunteers living in Izmir, Turkey, were examined for the presence of beta-lactamase producing Escherichia coli by selection on agar plates containing ampicillin (10 mg/L). Thirty-nine (78%) of the strains were ampicillin-resistant and ampicillin MIC50 values for these isolates were > or =1024 microg/ml (range 32- > or =1024 microg/ml). Ampicillin MIC values remained above 64 microg/ml in 16 (41%) strains despite addition of clavulanic acid (2 mg/L). Beta-lactamase production of the clavulanate-resistant strains was further investigated by analytical isoelectric focusing (pI). Enzymes with pIs of 5.4, 5.6, 7.4, 7.6 and >8.5 were detected. Sixty-nine percent of the isolates produced a pI 5.4 enzyme that cofocused with TEM-1. Beta-lactamase assays revealed that hyperproduction of these enzymes was the predominant mechanism for clavulanate resistance. Twelve (75%) of the isolates were able to transfer their ampicillin resistance. The ampicillin and ampicillin plus clavulanic acid MIC values of all transconjugants were above 256 microg/ml. Transferable ampicillin resistance was associated with resistance to other antibacterials at the following frequencies: tetracycline 92%, trimethoprim 83%, streptomycin 50%, gentamicin 25%, and chloramphenicol 8%. In conclusion, it has been suggested that commensal bacteria in normal populations make up the largest reservoir of antibiotic-resistant genes. Although the exact molecular mechanisms could not be determined, the current study shows that the incidence of ampicillin and clavulanic acid resistance is also high in commensal fecal flora.

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.

High prevalence of extended spectrum beta-lactamase production among Klebsiella pneumoniae strains isolated at a University Hospital in Turkey.

Beta-lactam susceptibility and beta-lactamase patterns of a random sample of 44 Klebsiella pneumoniae strains that had been isolated from nosocomial infections at Dokuz Eylül University Hospital in Izmir, were investigated. All strains were amoxycillin resistant but in the presence of clavulanic acid 26 became sensitive. Similarly 39 of the strains were resistant to ceftazidime and cefotaxime; clavulanic acid restored sensitivity to ceftazidime in 28 and to cefotaxime in 25 of these resistant strains. Extended spectrum beta-lactamase (ESBL) production was positive in 84% of the isolates as determined by the double disk synergy test. Isoelectric focusing revealed that each strain produced one to four beta-lactamases, pI 7.6 enzymes being the most prevalent. Other enzymes with pIs of 8.4, 8.2, 5.4, 7.8 were also detected. Resistance to ceftazidime was transferred from 18 of the 44 isolates to the recipient Escherichia coli K-12 at 37 degrees C. The transconjugants were examined for their plasmid content and the plasmids were characterized by their size and resistance profile. Fourteen different restriction pattern groups were identified with Eco R1. The results indicate a high prevalence of ESBL production in nosocomial K. pneumoniae isolates in Izmir and have major implications concerning the clinical use of later generation cephalosporins.

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.

Transferable trimethoprim resistance in Shigella strains.

The susceptibility patterns of 35 Shigella isolates (16 S. flexneri, 14 S. dysenteriae and 5 S. sonnei) to trimethoprim (Tp) and various antibiotics including amoxycillin, amoxycillin-clavulanic acid, nalidixic acid, ciprofloxacin, ceftazidime and ceftriaxone, were investigated. Twenty-two (62.8%) strains were resistant to Tp with a minimal inhibitory concentration (MIC50) value of 512 mg/L. Only six isolates were amoxycillin resistant, to which clavulanic acid restored sensitivity in all of them. None of the isolates were resistant either to extended spectrum cephalosporins or to quinolones. Resistance to Tp was transferred from 7 of the 22 isolates (31.8%) to the recipient Escherichia coli K12. Tp MIC values of the transconjugants were 512 mg/L. In no strain could amoxycillin resistance be transferred. Our results indicate that as the prevalence of transferable Tp resistance in Shigella isolates in Izmir is substantially high, alternative antimicrobial agents should be considered for empirical antibiotic therapy.