Emel Sesli Çetin

Comparison of the BACTEC blood culture system versus conventional methods for culture of normally sterile body fluids.

This study compared the BACTEC™ blood culture system (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md) with conventional culture methods for recovery and time to detection of significant isolates from normally sterile body fluids. A total of 412 specimens were included in the study. Half of the specimens were inoculated directly into the automated blood culture system. The remaining specimens were centrifuged at 3000 rpm for 10 min and were inoculated onto conventional media. Clinically significant microorganisms were isolated from 41 specimens (10%) by both culture systems; however, for 62 specimens (14.9%), growth was detected only with the BACTEC system. No isolates were detected with only conventional culture methods. A significant difference was noted between the blood culture system and routine culture methods for recovery of pathogenic microorganisms that were from sterile body fluids. The most frequently isolated microorganisms recovered only with the blood culture system were gram-positive cocci; gram-negative bacilli were the most frequently isolated microorganisms that were recovered with both culture methods.Streptococcus pneumoniae, Streptococcus viridans,Aeromonas hydrophila, andBrucella were recovered only with the blood culture system. Furthermore, the mean time to detection of significant pathogens was significantly less with the blood culture system than with conventional media. The BACTEC blood culture system was found to improve the yield of clinically significant isolates from normally sterile body fluids with reduced time to detection; it may be advantageous for isolation of fastidious microorganisms, such asBrucella andS pneumoniae, especially from cerebrospinal and synovial fluid specimens.

Distribution of genes encoding resistance to macrolides, lincosamides and streptogramins among clinical staphylococcal isolates in a Turkish university hospital.

This study investigated the prevalence of genes encoding resistance to macrolides, lincosamides and streptogramins (MLS(B)) among staphylococci in a series of 301 erythromycin-resistant clinical isolates of Staphylococcus aureus and coagulase-negative staphylococci (CoNS). Erythromycin-resistance phenotypes were determined according to Clinical and Laboratory Standards Institute guidelines and specific resistance genes erm(A), erm(B), erm(C), msr(A) and msr(B) were identified using polymerase chain reaction. Two hundred of 301 (66.5%) erythromycin-resistant staphylococcal isolates exhibited resistance to MLS(B) antibiotics. Of these, 127 (63.5%) exhibited a cMLS(B) resistance phenotype (resistant to both erythromycin and clindamycin), whereas 73 (36.5%) expressed the iMLS(B) resistance phenotype (resistant to erythromycin and susceptible to clindamycin). The most prevalent resistance determinants were erm(A) (62%) among S. aureus and erm(C) (30%) among CoNS isolates. Combinations of resistance mechanisms were rarely seen, and occurred most often in oxacillin-resistant isolates. The results of the present study support the idea that there are geographical differences in the prevalence of erythromycin resistance mechanisms among staphylococci, therefore local surveillance studies are important tools for guiding therapy and in the promotion of judicious use of antimicrobial agents.

Macrolide-lincosamide-streptogramin B resistance phenotypes in clinical staphylococcal isolates

The prevalence of macrolide-lincosamide-streptogramin B (MLSB) resistance as well as the MLSB resistance phenotypes were investigated by the double-disk diffusion test among 532 clinical staphylococci isolates in a Turkish university hospital. The activity of other antimicrobials, including trimethoprim/sulfamethoxazole, telithromycin, quinupristin/dalfopristin, linezolid, gentamicin, chloramphenicol, ciprofloxacin and vancomycin, was also evaluated. Of 532 isolates, 38.5% were resistant to MLSB antibiotics; 63.9% of the resistant isolates exhibited a constitutive phenotype (cMLSB) whereas 36.1% expressed an inducible resistance phenotype (iMLSB). MLSB resistance was more prevalent among coagulase-negative staphylococci (CoNS) strains. Oxacillin-resistant strains exhibited significantly higher MLSB resistance rates compared with oxacillin-susceptible strains (P<0.0001). The most frequently detected resistance phenotype among the total staphylococcal isolates was the constitutive type and this phenotype was more frequently encountered among oxacillin-resistant strains. With the exception of the fully active agents such as vancomycin, linezolid and quinupristin/dalfopristin, the most effective antibiotics were telithromycin and chloramphenicol among all isolates. Susceptibility rates to other antibiotics tested were higher among isolates without MLS(B) resistance than isolates with MLSB resistance. The detection of a considerable rate (43.5%) of iMLSB resistance among erythromycin-resistant/clindamycin-susceptible strains suggests that the true percentage of clindamycin resistance may be underestimated if testing for inducible resistance is not performed.

Epidemiologic characterization of nosocomial Acinetobacter baumannii infections in a Turkish university hospital by pulsed-field gel electrophoresis.

BACKGROUND Although members of the Acinetobacter genus are not commonly part of the human flora, their relatively high prevalence in hospital environment frequently results in colonization of the skin and respiratory tract. OBJECTIVES The present investigation was carried out to elucidate epidemiologic characteristics of nosocomial Acinetobacter baumannii infections in a teaching hospital. METHODS Epidemiologic, clinical, and demographic features of the 66 patients with A baumannii infection during a 14-month period were recorded. Antibiotic susceptibilities of the isolates were determined by the standardized disk-diffusion method, and the clonal relationship of the isolates was analyzed by pulsed-field gel electrophoresis (PFGE). RESULTS The incidence of A baumannii infection was especially high in January, April, May, and June 2006. The isolates were most frequently obtained from blood and tracheal aspirates sent from the intensive care unit and neurosurgery ward. Although the most frequently identified predisposing factors were cerebrovascular disease and surgical operation, the main risk factors identified in these patients were catheterization and mechanical ventilation. Genotype analysis of the 66 A baumannii strains by PFGE revealed the circulation of 36 different PFGE types, of which type A (12) and K (17) accounted for 44% of the isolates. We found high clonal relationship (80.3%) among the typed strains. Thirteen antibiotypes were observed. Most of the isolates were multidrug resistant. Resistance to imipenem, meropenem, gentamicin, amikacin, tobramycin, netilmicin, ampicillin-sulbactam, trimethoprim-sulfamethoxazole, piperacillin-tazobactam, cefoperazone-sulbactam, ciprofloxacin, and levofloxacin were found in 44%, 47%, 47%, 84.8%, 21.2%, 3%, 62.1%, 57.6%, 94%, 62.1%, 95.5%, and 95.5% of the isolates, respectively. CONCLUSION The epidemiologic data obtained suggested that the increase in the number of A baumannii infections in our hospital was caused by the interhospital spread of especially 2 epidemic clones. We determined that clonally related strains can survive for a long time in our hospital and cause nosocomial infections in the predisposed patients.

Microbiological Evaluation of Octenidine Dihydrochloride Mouth Rinse after 5 Days' Use in Orthodontic Patients

OBJECTIVE To determine the absolute and relative antibacterial activity of octenidine dihydrochloride (OCT) against total and cariogenic bacteria in saliva samples of patients with fixed orthodontic appliances during 5 days of usage. MATERIALS AND METHODS The study group consisted of 5 male and 13 female subjects who were selected from patients in the Clinic of Orthodontics. Each patient was given physiologic saline (PS), chlorhexidine gluconate (CHX), polyvinylpyrrolidone-iodine complex (PVP-I), and OCT every morning for 5 days, each separated by a 2-week interval. Total and cariogenic bacteria in saliva samples of orthodontically treated patients with fixed appliances were collected during 5 days of usage. Unstimulated saliva was collected as a baseline sample. Saliva samples were collected at 15 minutes, and on the second, third, and fifth day after rinsing the mouth with any of the solutions for 30 seconds, and bacterial counts were detected. RESULTS OCT showed an ultimate reduction of total viable oral bacteria, Lactobacillus species, and Streptococcus mutans in vivo. OCT also had a significantly greater inhibitory effect than 0.2% CHX and 7.5% PVP-I, from the beginning of the study until the fifth day after the orthodontic appliances were bonded (P < .1). CONCLUSIONS OCT compared favorably with respect to CHX and PVP-I complex in orthodontically treated patients with fixed appliances (P </= .1).

Short-term relative antibacterial effect of octenidine dihydrochloride on the oral microflora in orthodontically treated patients.

OBJECTIVE To evaluate the efficacy of common antiseptic mouth rinses and octenidine dihydrochloride (OCT). METHODS The antibacterial activities of antiseptics against total and cariogenic bacteria (Streptococcus mutans and Lactobacillus species) in saliva were studied in vitro and in vivo. After unstimulated saliva was collected, one of the mouth rinse solutions was applied for 30seconds. Saliva samples were collected 15, 30, 60, and 120min later and evaluated for their bacterial count. RESULTS OCT had a significantly greater inhibitory effect on the studied bacteria than 0.2% chlorhexidine gluconate (CHX) and 7.5% polyvinylpyrrolidone-iodine complex (PVP-I) from 15min to 120min following the application (p<0.01). The antiseptic efficacy of 0.2% CHX on total bacteria and Lactobacillus species was very similar to the efficacy observed with 7.5% PVP-I mouth solution from 15min up to 120min. Streptococcus mutans was completely inhibited by 0.15mg/ml PVP-I, 0.5mg/ml CHX, and 0.1mg/ml OCT concentrations, while Streptococcus salivarius was inhibited by 0.15mg/ml PVP-I, 2mg/ml CHX, and 0.8mg/ml OCT concentrations. Lactococcus lactis subspecies lactis was inhibited with 0.00313mg/ml OCT, 30mg/ml PVP-I, and 0.0063mg/ml CHX concentrations. CONCLUSIONS OCT compared favorably with CHX and PVP-I in its antibacterial effects, both in vitro and in vivo (p<0.01).

Efficacy of endodontic applications of ozone and low‐temperature atmospheric pressure plasma on root canals infected with Enterococcus faecalis

This study aimed to compare the antimicrobial efficacy of low‐temperature atmospheric pressure plasma (LTAPP) design and gaseous ozone delivery system with 2·5% NaOCl on Enterococcus faecalis in root canal walls and dentine tubules. The samples were divided into LTAPP (n = 12), ozone (n = 12), NaOCl (positive control, n = 12) and saline (negative control, n = 6) groups. Microbial samples were collected using paper points and dentin chips from root canals. Antimicrobial efficacy was assessed by counting the colony‐forming units of Ent. faecalis before and after each irrigation protocol. Data were analysed using Kruskal–Wallis, Wilcoxon signed‐rank, Friedman and Bonferroni t (Dunns test)‐tests (P = 0·05). The microbial sampling with paper points showed antibacterial efficacy of NaOCl, LTAPP, ozone and saline in descending order, respectively (P < 0·05). The microbial sampling with dentin chips demonstrated a superior efficacy of LTAPP compared with NaOCl in the middle third (P < 0·05), while both had similar effects in coronal and apical thirds (P > 0·05). NaOCl and LTAPP were better than ozone at the coronal and middle parts of the root canals (P < 0·05). These findings led us to suggest that LTAPP, which has no thermal and chemical effects, may be of great aid in endodontic treatment.

Investigation of Panton-Valentine leukocidin expressing Staphylococcus aureus colonization among children in a child care center

The presence of Panton-Valentine leukocidin expressing Staphylococcus aureus colonization was investigated with a qualitative nucleic acid hybridization assay among 122 children and 19 staff in a child care center. Genotyping of 5 Panton-Valentine leukocidin-positive isolates by pulsed-field gel electrophoresis revealed that one child and a teacher from the same class were colonized with the clonally related strains. This finding allowed us to suggest that close contact with colonized people is a risk factor for being colonized.

Health care-associated infection surveillance in a tertiary neonatal intensive care unit: A prospective clinical study after moving to a new building.

BACKGROUND There are very few prospective clinical studies on neonatal health care-associated infection (HAI) surveillance. HAI surveillance helps reduce not only mortality, but also morbidity, length of hospital stay, and health care costs. METHODS This prospective clinical study covered a period of 12 months in a tertiary neonatal intensive care unit (NICU). HAI rates were calculated using different denominators: number of patients hospitalized in the NICU, number of patient-days, and number of specific device-days. RESULTS The HAI rate was 18%, and the incidence density was 17/1,000 patient-days. The most common HAI was bloodstream infection (n = 34; 50%). The most common pathogen was coagulase-negative staphylococci (CoNS; 54.9%) in gram-positive bacteria and in general. Methicillin resistance was 96.4% for CoNS. Klebsiella spp (13.7%) was the most common gram-negative bacteria. Extended-spectrum β-lactamase positivity was 14.3% for Klebsiella spp and 25% for Escherichia coli. HAI-related mortality was 0.3%. CONCLUSIONS NICUs should perform their own HAI surveillance with prospective clinical design. Attention paid to handwashing, disinfection and sanitizing, complying with the terms of asepsis, extending in-service training, increasing the number of medical staff, preventing frequent changes in health care staff positions, and improving physical environmental conditions in NICUs might eventually decrease HAI rates.

Eosinophil cationic protein in patients with fascioliasis: Its probable effects on symptoms and signs

Eosinophilia is 1 of the most common signs of fascioliasis especially during acute stage. In this study, our aim was to determine eosinophil cationic protein (ECP) in the sera of patients with fascioliasis and to investigate the likely relation between ECP and symptoms and signs of fascioliasis. Presence of high liver enzyme levels, eosinophilia, abdominal pain or urticaria was not found to be significantly associated with ECP positivity (p>0.05), but statistical analyses revealed that ECP positivity was significantly related to weight loss status of patients (p<0.005). In conclusion, ECP may be 1 of the likely causes of the symptoms and signs of fascioliasis.