Kan akımı infeksiyonlarından izole edilen Staphylococcus aureus suşlarında antimikrobiyal direnç paterni

Amaç: Staphylococcus aureus kan dolaşımı enfeksiyonlarının önde gelen nedenlerinden birisidir. Bu çalışmada nozokomiyal kan akımı enfeksiyonlardan izole edilen S. aureus suşlarının kullanılan antibiyotiklere direnç oranlarının tespit edilmesi amaçlanmıştır. Gereç ve yöntem: Çalışmamızda Ocak 2009–Haziran 2013 arasında Cumhuriyet Üniversitesi Tıp Fakültesi Uygulama ve Araştırma Hastanesinde kan dolaşımı enfeksiyonlarından izole edilen S. aureus suşları incelenmiştir. Suşların tanımlanması ve antimikrobiyal duyarlılık testleri Clinical and Laboratory Standards Institute CLSI önerilerine göre otomatize sistem BD, Phoenix, USA kullanılarak yapılmıştır. Bulgular: Çalışmamızda nozokomiyal kan dolaşımı enfeksiyonlarından izole edilen 257 S. aureus suşu incelenmiştir. Çalışmamız süresi içerisinde metisilin direnci ortalama %8.9 olarak tespit edilmiştir. Bu süre içerisinde vankomisin, teikoplanin ve linezolid’e karşı dirençli suş saptanmamıştır. Metisilin dirençli olan 23 suşun yıllar içerisinde vankomisin minimal inhibisyon konsantrasyonu MİK değerlerinde yıllara göre anlamlı bir değişim saptanmamıştır. Metisiline dirençli Staphylococcus aureus MRSA suşlarının, metisilin duyarlı Staphylococcus aureus MSSA suşlarına oranla anlamlı düzeyde daha yüksek direnç oranlarına sahip olduğu görülmüştür. Sonuç: Staphylococcus aureus suşları ile yapılan direnç çalışmalarında farklı merkezlerden farklı oranlar bildirilmektedir. Bu nedenle ilaçlara karşı oluşan direnç gelişimi ile ilgili olarak merkezler bilgilerini sürekli güncellenmeli ve paylaşmalıdırlar. Çalışmamız sonucunda ortaya koyduğumuz lokal verilerin, ilgili bakterilere bağlı nozokomiyal kan dolaşımı enfeksiyonları ile mücadelede kullanılarak başarılı ampirik tedavi modellerinin oluşturulmasında ve bu mikroorganizmaların yayılımının önlenmesinde etkili olabileceğini düşünmekteyi

Antimicrobial Resistance Patterns of Enterococcus faecalis and Enterococcus faecium Bacteria Isolated from Bloodstream Infections

Introduction: Enterococci have recently become one of the most common causes of nosocomial bloodstream infections. Today, these bacteria account for about 10% of all bacteria. This study aimed to determine the rates of resistance to antibiotics that are commonly used in the treatment of Enterococcus faecalis and Enterococcus faecium strains isolated from nosocomial bloodstream infections. Materials and Methods: The study included the E. faecalis and E. faecium strains isolated from bloodstream infections at the Practice and Research Hospital of the Faculty of Medicine, Cumhuriyet University over a total period of four and a half years between (January 2009 and June 2013). Strain typing and antimicrobial sensitivity testing were performed using an automated system (BD, Phoenix, AZ, USA) according to the guidelines of the Clinical and Laboratory Standards Institute. Nosocomial bloodstream infection diagnosis was based on the diagnostic criteria of the Centers for Diseases Control and Prevention. Results: One hundred and three enterococci strains were isolated from nosocomial bloodstream infections during the study period. 51 (49.5%) of these strains were typed as E. faecalis and 52 (50.5%) as E. faecium. While there were 44 (84.6%) ampicillin-resistant strains among E. faecium isolates, this number was 2 (3.9%) (p= 0.001) among E. faecalis strains. High-level aminoglycoside resistance rate (500 µg/mL) was higher among E. faecium isolates compared with E. faecalis isolates (63.5% vs. 33.3%; p= 0.002). While no linezoid or daptomycin resistance was noted among the strains, only 2 (1.9%) of a total of 103 enterococci strains were found to be resistant to both vancomycin and teicoplanin. Conclusion: Problems caused by the resistance of nosocomial pathogens to antimicrobials are rapidly increasing. Therefore, clinical centers should constantly update and share their available data in relation to drug resistance. We consider that the local findings of this study, conducted at a university hospital, can be used particularly in fighting against nosocomial enterococcal infections to contribute to the formation of successful empirical treatment models

The Prevalence of Extended-Spectrum Beta-Lactamase and Antibiotic Resistance among Escherichia coli and Klebsiella pneumoniae Isolates Responsible for Nosocomial Blood-Stream Infections

Introduction: This study aimed to identify the extended-spectrum beta-lactamase (ESBL) production prevalence of Escherichia coli and Klebsiella pneumoniae strains isolated from nosocomial bloodstream infections as well as their resistance to the antibiotics used. Materials and Methods: This study examined the E. coli and K. pneumoniae strains isolated from blood-stream infections at the Health Care and Research Hospital, Faculty of Medicine, Cumhuriyet University, between 2009 and 2012. Strain description and antimicrobial susceptibility tests were carried out using an automated system (BD, Phoenix, AZ, USA) based on the recommendations of the Clinical and Laboratory Standards Institute (CLSI). Results: This study examined 321 E. coli and 104 K. pneumoniae strains isolated from nosocomial blood-stream infections. ESBL was found in 38.3% of E. coli strains and in 26.9% of K. pneumoniae strains isolated from blood cultures. No resistance was found in any strains to carbapenems. Amikacin was considered to be the second-least resistant antibiotic for these strains. One hundred and thirtyfour of the 425 nosocomial strains were isolated from intensive care units and 291 from other services. Fifty-six percent of strains isolated from intensive care units were found to be E. coli and 44% as K. pneumoniae. ESBL was found in 57.3% of E. coli and 30.5% of K. pneumoniae strains isolated from intensive care units, and this ratio was found to be 32.5% and 22.2%, respectively, for other units. Conclusion: Increasing rates of resistance are being reported worldwide in studies carried out with E. coli and K. pneumoniae strains raising future concerns. Thus, resistance data should be constantly updated. We conclude that the local data gathered in this study can be used in the fight against relevant bacterial nosocomial bloodstream infections and can be effective in creating successful empirical treatment models and preventing the spread of such microorganisms

Aspergilloma Occurred in Preexisting Tuberculous Cavity in a Patient with Acquired Immune Deficiency Syndrome

Aspergillus fungus balls develop preexisting cavities in the pulmonary apex of patients with chronic lung disease such as tuberculosis. Acquired Immune Deficiency Syndrome (AIDS) predisposes to reactivation of tuberculosis. Efficacy of antifungal therapy in invasive aspergillosis has been extremely poor in immunsupressed patients such as AIDS. An aspergilloma case developing on the preexisting tuberculosis cavity in the 36 years old patient who was followed up as AIDS is evaluated in this case report

Antimicrobial Susceptibility and Frequency of Extended Spectrum Beta-Lactamase (ESBL) of Escherichia coli Strains Isolated from Community Acquired and Nosocomial Infections

Introduction: Escherichia coli is one of the most important causes of nosocomial and community acquired infections. Beta-lactam antibiotics constitute one of the major therapeutic options to treat infections caused by these microorganism. Resistance to beta-lactams antibiotics is mainly caused by extended-spectrum beta-lactamases (ESBLs). The aim of this study was to determine the production rates of ESBL of E. coli isolates causing nosocomial and community acquired infections as well as to determine their antimicrobial susceptibility patterns. Materials and Methods: Between June 2006-December 2010, 555 E. coli strains isolated from clinical specimens (256 wound, 213 urine, 42 blood, 28 respiratory truct, 16 others) of inpatients, and 3052 E. coli strains isolated from urines of outpatients admitted to Cumhuriyet University Research and Training Hospital, were included to the study. Identification of the isolates and antibiotic susceptibility testings were performed by an automatic system (BD, Phoenix, USA). The production of ESBL was done by the broth microdilution method according to Clinical and Laboratory Standards Institute guidelines. Results: The rate of ESBL producers in the nosocomial isolates was approximately three times higher than the community acquired isolates (47.7% vs. 15.8%). Ciprofloxacin and piperacillin-tazobactam resistance rate were significantly different between the nosocomial and community acquired ESBL producing E. coli isolates. Ciprofloxacin resistance was higher in community acquired strains (84.3% vs. 77.7%, p= 0.026) and piperacillin-tazobactam resistance was higher in nosocomial strains (44.5% vs. 37.1%, p= 0.046). Nitrofurantoin and fosfomycine resistance in the community acquired ESBL positive E. coli strains was quite low (4.0% vs. 0.5%), and the nosocomial isolates were not studied. All nosocomial and community acquired E. coli isolates were sensitive to carbapenems. Conclusion: These results show that ESBL production is high in nosocomial E. coli isolates, and some differences can be seen in antibiotics susceptibility of nosocomial and community acquired ESBL producing E. coli strains

Vancomycin Resistant Enterococcus Outbreak in a University Hospital: Investigation of Risk Factors

Introduction: In this study, independent risk factors for the acquisition of vancomycin resistant enterococcus (VRE) were investigated prospectively between September 2011 and March 2012 in a nosocomial VRE outbreak at a university hospital. Materials and Methods: After the detection of a VRE strain from wound culture sample of an inpatient in September 2011, a VRE outbreak was assumed in the hospital, and VRE surveillance was performed both at high-risk and VRE detected clinics. For the detection of gastrointestinal system (GIS) VRE colonization, weekly rectal swab specimens were taken from the hospitalized patients and when considering an infection, blood, urine and wound specimens were sent to the microbiology laboratory for each patient. The patients whom rectal swab and/or clinical specimens yielded VRE were accepted as VRE positive. Determining vancomycin resistance genotype among the VRE strains were done with multiplex polymerase chain reaction technique (GenExpert®, USA) by using the special test kits (Xpert®, USA). Results: During the seven-month of VRE outbreak, a total of 74 VRE positive patients, 6 (8.1%) of whom infected by a VRE in seven different clinics were determined. These 74 VRE positive patients and 1136 patients who were accepted as VRE negative (all were hospitalized in the same clinical wards) by the surveillance cultures were divided into two groups for comparing patient characteristics. A multivariate logistic regression analysis showed sulbactam-ampicillin [Odds ratio (OR) 3.18, 95% confi dence interval (95% CI) 1.70-5.97; p< 0.001], vancomycin (OR 5.16, 95% CI 1.92-13.9; p= 0.001), piperacillin/tazobactam (OR 4.09, 95% CI 1.85-9.45; p= 0.001), carbapenems (imipenem, meropenem) (OR 2.43, 95% CI 2.03-10.1; p< 0.001) and amikacin (OR 7.4, 95% CI 2.71-20.19; p< 0.001) use, all were detected as independent risk factors for VRE positivity. Further, diabetes mellitus (OR 2.44, 95% CI 1.31-4.53; p= 0.005), abdominal surgical operation (OR 2.49, 95% CI 1.18-5.29; p= 0.017), and the application of a nasogastric feeding tube (OR 0.31, 95% CI 0.13- 0.75; p= 0.01) were also determined as independent risk factors for VRE-acquisition. Seventy-three out (98.6%) of 74 VRE strains were both vancomycin [minimum inhibitor concantration (MIC) > 16 μg/mL)] and teicoplanin (MIC > 16 μg/mL) resistant (vanA genotype) Enterococcus faecium. Conclusion: The use of parenteral form of broad spectrum antibiotics and underlying diseases like diabetes and nasogastric tube applications, all increase nosocomial VRE risk