[Investigation of role of anaerobic bacteria in cystic fibrosis patients]. / Kistik fibrozisli hastalarda anaerop bakterilerin rolünün arastirilmasi.

INTRODUCTION: Repetitive pulmonary infections are the main cause of morbidity and mortality in cystic fibrosis (CF) patients. In recent years, non-culture dependent metagenomic studies showed complex dynamics of the pulmonary environment of CF patients and pointed out the importance of anaerobic bacteria. Molecular-based studies indicate that anaerobic bacteria can be found more than aerobic or facultative anaerobic bacteria in CF lung environment. However, limited number of studies are far away to clarify the importance of anaerobic bacteria in CF pulmonary disease. MATERIALS AND METHODS: The aim of this study was to evaluate the role of anaerobic bacteria in CF patients admitted to Hacettepe University, Pediatric Respiratory Diseases Department, by using quantitative culture method for both aerobic and anaerobic bacteria. Anaerobic bacteria were identified by conventional and semi-automated methods. Antibiotic susceptibilities were performed by agar dilution method. RESULT: Seventy-seven anaerobic bacteria were isolated from 35 (81.4%) of 43 patients. The total count of anaerobes and facultative bacteria (mean 16 x 106), was higher than aerobes and facultative bacteria (mean 14.1 x 106). If anaerobe culture were not performed merely 63.65% of all species could be obtained. In patients whose samples yielded intermediate or high numbers of PMNLs, significantly more obligate anaerobic bacteria were isolated (p= 0.046). Patients older than 18 years were colonized with higher number of anaerobic bacteria. Susceptibilities of 72 isolates out of 77, against ampicillin, sulbactam-ampicillin, piperacillin, piperacillin-tazobactam, moxifloxacin, metronidazole, imipenem, and clindamycin were also evaluated. Clindamycin was found to be the least effective antibiotic among all. None of the isolates was resistant to imipenem. CONCLUSIONS: This is the first study to show the role and importance of anaerobic bacteria in CF patients in our country. The resistance rates in anaerobic bacteria isolated from CF patients is concerning. Therefore, intermittent anaerobic culture and follow-up of resistance rates will be helpful in the follow-up of these patients.

[Investigation of macrolide-lincosamide-streptogramin B (MLS(B)) and telithromycin resistance in clinical strains of staphylococci]. / Stafilokok klinik izolatlarinda makrolid-linkozamid-streptogramin B (MLS(B)) ve telitromisin direncinin arastirilmasi.

The aim of this study was to determine the prevalence of macrolide-lincosamide-streptogramin B (MLS(B)) resistance and also to search for telithromycin resistance in staphylococcus strains isolated at Hacettepe University Hospital, Ankara, Turkey. A total of 381 Staphylococcus aureus isolates and 94 coagulase-negative staphylococci (CNS) were tested by disc approximation method. Methicillin resistance of these isolates was searched by disc diffusion test using 30 microg cefoxitin discs. Distribution of erm genes was detected by PCR method. Of 381 isolates 112 (29.4%) S. aureus and 58 (61.7%) CNS were found to be resistant to erythromycin. Among these, the inducible MLS(B) (iMLS(B)) resistance was the most prevalent pattern, being 56.2% and 41.4% among S. aureus and CNS isolates, respectively. The frequency of constitutive MLS(B) resistance (cMLS(B)) was 40.2% for S. aureus and 34.5% for CNS. Macrolide-streptogramin B (MS(B)) resistance pattern was detected only in CNS isolates (24.1%). In 4 (3.6%) of S. aureus isolates mixed pattern demonstrating both inducible and constitutive patterns was detected. None of the isolates susceptible to erythromycin showed resistance to telithromycin. As a remarkable finding of this study D-shaped inhibition zones around the telithromycin discs was observed in all of the isolates with iMLS(B) and macrolide-streptogramin B (MS(B)) resistance phenotypes. The isolates showing cMLS(B) pattern were also resistant to telithromycin (no zone of inhibition around the telithromycin discs). A total of 170 erythromycin resistant staphylococcal isolates were tested for the presence of erm and msrA genes. Among the S. aureus isolates with iMLS(B) and cMLS(B) phenoypes, the most common findings were the detection of ermA (44/63) and ermA + ermC (35/45) genes, respectively. All of the four isolates with mixed phenotype harboured ermA gene. With respect to CNS isolates, the most frequently detected gene was ermC (37/58); whereas iMLS(B) and cMLS(B) resistant CNS isolates had ermC (11/24) and ermA + ermC (10/20) as the most prevalent resistance genes, respectively. msrA gene was detected in 11 of 14 CNS isolates with MS(B) resistance. Two of these were also carrying ermA while 3 isolates harboured ermCalong with msrA gene. The results of this study showed that inducible MLS(B) resistance was the most prevalent phenotype among the clinical staphylococcal isolates in our hospital. All of these isolates also demonstrated inducible resistance pattern against telithromycin, a new antibiotic suggested particularly for the treatment of infections with iMLS(B) resistant bacteria. The telithromycin resistance patterns need to be tested in other centers and the impact of this issue on the clinical use of telithromycin should be investigated.

[In vitro activity of tigecycline against methicillin-resistant staphylococci]. / Metisiline dirençli stafilokoklarda tigesiklinin in vitro etkinliginin arastirilmasi.

Glycylcyclines are novel semisynthetic group of antibiotics that have been produced by substitution of glycylamido group at position 9 of tetracyclines. Tigecycline derived from minocycline is the first member of glycylcyclines. This new antibiotic has a broad spectrum of activity against variety of gram-positive and gram-negative bacteria and is not affected by known tetracycline resistance mechanisms. The aim of this study was to investigate the in-vitro activity of tigecycline as well as vancomycin, linezolid, quinupristin-dalfopristin and trimethoprim-sulphamethoxazole (TMP-SMX) against methicillin-resistant staphylococci isolated from clinical specimens of adult patients in Hacettepe University Hospital. For this purpose 127 Staphylococcus aureus (MRSA) and 42 coagulase negative staphylococci (MRCNS) which had been shown to be resistant to methicillin by disc diffusion method performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines, were evaluated. In these isolates minimum inhibitory concentration (MIC) values of tigecycline were detected by E-test; susceptibilities to linezolid, quinupristin-dalfopristin, TMP-SMX were detected by disc diffusion test. All of the isolates were searched for decreased susceptibility to vancomycin by agar screening method and MIC values of vancomycin were detected by E-test for the strains that grew on vancomycin agar plates. The range of MIC values of tigecycline were 0.032-1 microg/ml for the 127 MRSA isolates (MIC50 0.25 microg/ml, MIC90 0.75 microg/ml) and were 0.047-1 microg/ml (MIC50 0.25 microg/ml, MIC90 0.5 microg/ml) for the MRCNS isolates. All staphylococcal isolates were found to be susceptible to vancomycin, linezolid and quinupristin-dalfopristin. TMP-SMX resistance was detected in 7 (5.5%) MRSA and 26 (60.5%) MRCNS isolates. The results of this study demonstrated very good in-vitro activity of tigecycline against both MRSA and MRCNS isolates in our hospital. A remarkable finding of the present study was demonstration of the quite low rate of TMP-SMX resistance among MRSA isolates whereas MRCNS isolates showed high rate of resistance.

In vitro activity of tigecycline as a therapeutic option against multidrug-resistant Acinetobacter spp.

The study was performed to detect the in vitro activity of tigecycline in multidrug-resistant Acinetobacter isolates from patients in Hacettepe University Adult Hospital, Turkey. The microorganisms were isolated from clinical specimens of patients with respiratory and bloodstream infections. Thirty (66.7%) of the 45 inpatients were in ICUs. In vitro activity of imipenem, meropenem, ceftazidime, ciprofloxacin and aztreonam in 124 Acinetobacter species isolated was evaluated by microdilution test. Overall, 51 (41%) Acinetobacter spp. were found to be resistant to > or = 3 antibiotics belonging to different antimicrobial classes and defined as multidrug-resistant (MDR). Among the MDR Acinetobacter spp. 32 (62.7%) were Acinetobacter baumannii and 19 (37.3%) Acinetobacter lwoffii. In vitro activity of tigecycline against MDR isolates were studied by E-test. Each MDR isolate was also tested for metallo-beta-lactamase (MBL) production using CLSI guidelines. Forty-five (88.2%) of the isolates were found to produce MBL. The MIC90s of all antimicrobial agents tested except tigecycline were > or = 64 microg/ml whereas the MIC50, and MIC90 of tigecycline were found 1 microg/ml and 1.5 microg/ml, respectively. ERIC-PCR results revealed that bloodstream and respiratory isolates had nine and six different patterns, respectively. In conclusion, tigecycline has been shown to have potent in vitro activity against MDR Acinetobacter spp. and might be of therapeutic value in the treatment of infections due to MDR Acinetobacter spp., including those harbouring MBLs. Further clinical trials are needed to confirm the efficacy of tigecycline in the management of MDR Acinetobacter infections.

A survey of antibiotic resistance in Streptococcus pneumoniae and Haemophilus influenzae in Turkey, 2004 2005.

OBJECTIVES: To determine the prevalence of antimicrobial resistance among Streptococcus pneumoniae and Haemophilus influenzae isolated in Turkey as part of Survey Of Antibiotic Resistance, a surveillance programme in the Africa and Middle East region examining the antimicrobial susceptibility of key bacterial pathogens involved in community-acquired respiratory tract infections (CARTIs). METHODS: Susceptibility was evaluated against a range of antimicrobial agents using disc diffusion and Etest methods. RESULTS: Six centres in five cities collected 301 S. pneumoniae and 379 H. influenzae isolates between October 2004 and November 2005. Among S. pneumoniae, the prevalence of isolates with intermediate susceptibility (MICs 0.12-1 mg/L) and resistance to penicillin (MICs >or=2 mg/L) was 24.6% and 7.6%, respectively; there was a wide variation between cities (2.4% to 36.9% intermediate and 0% to 23.8% resistant phenotypes). Macrolide-azalide resistance rates exceeded those of penicillin resistance in all cities. Overall, 5.0% of isolates were co-resistant to penicillin and erythromycin and 10.0% were multidrug-resistant (joint resistance to erythromycin, co-trimoxazole and tetracycline). Agents tested to which over 90% of countrywide S. pneumoniae isolates remained susceptible were amoxicillin/clavulanate (98.7%), chloramphenicol (94.7%) and cefprozil (90.6%). Overall, the percentage of H. influenzae isolates producing beta-lactamase was 5.5%, differing widely across the country with the highest prevalence of beta-lactamase production detected in Trabzon (14.0%) and no beta-lactamase-positive isolates found in Izmir. H. influenzae had the highest per cent susceptibility to amoxicillin/clavulanate (99.5%) and ofloxacin (99.2%) while >20% were resistant to co-trimoxazole. CONCLUSIONS: Prevalence of penicillin and macrolide-azalide resistance among S. pneumoniae appears to be on the increase in Turkey while overall beta-lactamase production in H. influenzae remains relatively low. To adequately monitor the spread of drug-resistant phenotypes among these two important CARTI pathogens, ongoing collection of resistance surveillance data is required-where possible locally as resistance patterns can vary substantially between cities and institutions.

[Anaerobic bacteria isolated from patients with suspected anaerobic infections]. / Anaerobik enfeksiyon süpheli hastalardan izole edilen anaerop bakteriler.

The study involved 394 clinical samples sent to the Clinical Microbiology Laboratory of Hacettepe University Adult Hospital between January 1997 and May 2004 for anaerobic cultivation. Since multiple cultures from the same clinical samples of the same patient were excluded, the study was carried on 367 samples. The anaerobic cultures were performed in anaerobic jar using AnaeroGen kits (Oxoid, Basingstoke, U.K.) or GENbox (bioMérieux, Lyon, France). The isolates were identified by both classical methods and "BBL Crystal System" (Becton Dickinson, U.S.A.). While no growth was detected in 120 (32.7%) of the clinical samples studied, in 144 samples (39.2%) only aerobes, in 28 (7.6%) only anaerobes and in 75 (20.5%) of the samples both aerobes and anaerobes were isolated. The number of the anaerobic isolates was 217 from 103 samples with anaerobic growth. Of these 103 samples 15 showed single bacterial growth whereas in 88 samples multiple bacterial isolates were detected. Anaerobic isolates consisted of 92 Gram negative bacilli (Bacteroides spp. 50, Prevotella spp. 14, Porphyromonas spp. 10, Fusobacterium spp. 7, Tisierella spp. 2, unidentified 9), 57 Gram positive bacilli (Clostridium spp.17, Propionibacterium spp. 16, Lactobacillus spp. 8, Actinomyces spp. 5, Eubacterium spp. 2, Bifidobacterium adolescentis 1, Mobiluncus mulieris 1, unidentified nonspore forming rods 7), 61 Gram positive cocci (anaerobic cocci 44, microaerophilic cocci 17), and 7 Gram negative cocci (Veillonella spp.). In conclusion, in the samples studied with prediagnosis of anaerobic infection, Bacteroides spp. (23%) were the most common bacteria followed by anaerobic Gram positive cocci (20.3%) and Clostridium spp (7.8%).