Sesin Kocagöz

Susceptibility testing of voriconazole, fluconazole, itraconazole and amphotericin B against yeast isolates in a Turkish University Hospital and effect of time of reading

Voriconazole is a promising azole effective against a variety of fungi, including yeasts. In this study, we tested in vitro activities of voriconazole, fluconazole, itraconazole and amphotericin B against some ATCC and reference strains and 250 clinical yeast isolates. We also evaluated the effect of time of reading on MIC results. Voriconazole was the most active agent against Candida and Trichosporon isolates, including the putatively fluconazole-resistant C. krusei (MIC(90) 0.25 microg/ml) and C. glabrata (MIC(90) 0.5 microg/ml). Amphotericin B MICs were scattered in a considerably narrow range in both RPMI 1640 and Antibiotic Medium 3. MICs at 24 hours and 48 hours were similar in general for all antifungals tested. The highest percentage of strains that showed 24-hour and 48-hour MICs within +/-1-log(2) dilution was observed for amphotericin B tested in RPMI (99%), and the lowest for amphotericin B tested in Antibiotic Medium 3 (80%). In conclusion, voriconazole is very effective against a wide spectrum of Candida species and 24-hour readings could substitute 48-hour MIC evaluation.

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

Abstract 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, ticar-cillin-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.

Comparison of cytochemical staining, immunofluorescence and PCR for diagnosis of pneumocystis carinii on sputum samples

Detection of P. carinii has increased with the use of polymerase chain reaction (PCR), particularly in sputum samples. In this study, sputum samples obtained from 30 immunosuppressed patients with respiratory symptoms (12 HIV-infected) were tested by standard cytochemical staining (Giemsa and methenamine silver), immunofluorescence (IF) staining and PCR for detection of P. carinii and the results were compared. Pneumocystis carinii was detected in 4, 8 and 13 sputum samples by cytological staining, IF test and PCR, respectively. Specific amplification bands were obtained in all sputum samples that were positive by both other tests. All tests gave negative results in sputum samples obtained from 5 HIV-infected asymptomatic patients and 22 non-immunosuppressed tuberculosis patients. Our observations suggest that PCR results were well correlated with P. carinii pneumonia (PCP), especially in non-HIV-infected patients. However, PCR positivity obtained in HIV-infected patients could be misleading in the diagnosis of PCP without careful clinical evaluation. Positive results obtained by Giemsa staining or IF test confirm diagnosis of PCP authoritatively. As a result, we suggest testing sputum samples by both PCR and IF techniques for detection of P. carinii.

Nosocomial bloodstream infections in a Turkish university hospital: study of Gram-negative bacilli and their sensitivity patterns

Treatment of nosocomial bacteraemia is usually governed by the surveillance results of the particular unit. Such results are especially important when antimicrobial resistance rates are high. Multiresistant isolates including Gram-negatives producing extended-spectrum beta-lactamases have been frequently reported in tertiary care units in Turkey. In this study, antimicrobial susceptibilities of Gram-negative blood isolates (n=348) were determined by microbroth dilution tests. The results showed carbapenems (meropenem and imipenem) to be uniformly more potent in vitro than any other drug against the Enterobacteriaceae. Quinolone antibiotics were more active in vitro than aminoglycosides against a range of bacteria. Gram-negative bloodstream isolates were highly resistant to many antimicrobial agents in the hospital. In order to prevent hospital infection and antimicrobial resistance, surveillance of aetiological agents must be performed regularly.

Analysis of a mini-outbreak of methicillin-resistant Staphylococcus aureus in a surgical ward by using arbitrarily primed-polymerase chain reaction

Abstract In November 1995, an increase was noticed in the number of methicillin-resistant Staphylococcus aureus (MRSA) isolates from a surgical ward at Hacettepe University Hospital. All MRSA isolates obtained from clinical specimens in this ward (14 MRSA isolates from wound cultures of 10 patients) were collected prospectively for 10 weeks. Surveillance cultures were taken from ward personnel (nose cultures from 4 physicians, 7 nurses, 1 secretary, 1 waiter), 2 surgical dressing containers and 1 nebulizer. MRSA was isolated from one of the surgical dressing containers, the nebulizer and nose cultures of 3 physicians, 3 nurses and the ward secretary. Arbitrarily primed polymerase chain reaction (AP-PCR) analysis showed that most MRSA isolates belonged to 2 major clones (pattern A, pattern B). Pattern A was the most frequent one and was present in 4 clinical isolates, surgical dressing container-1. Pattern B was identified in 3 clinical isolates and nose culture of physician-3. AP-PCR analysis revealed that this mini-MRSA outbreak was caused by contamination of surgical dressing container with MRSA and nasal MRSA carriage in ward staff. AP-PCR seems to be a valuable typing method for analysis of nosocomial MRSA outbreaks because of its simplicity and rapidity.

Comparative In Vitro Activity of Sparfloxacin against Gram-positive Cocci

Among Gram-positive organisms, enterococci, Staphylococcus aureus and coagulase-negative staphylococci are the most difficult pathogens to eradicate. High-level resistance to aminoglycosides and methicillin resistance are increasingly reported in Turkish isolates, rendering these drugs ineffective against these organisms. Sparfioxacin is a new quinolone that is active against both Gram-negative and Gram-positive bacteria (Barry & Fuchs 1991; Visser et al. 1991). This study investigated the in vitro activity of sparfioxacin in comparison with vancomycin, sulbactam-ampicillin, pefloxacin, ofloxacin, fleroxacin and ciprofloxacin against clinical isolates of enterococci, coagulase-negative staphylococci, and S. aureus. 1. Materials and Methods