An Investigation of the Bactericidal Activity of Chlorhexidine Digluconate Against Multidrug-Resistant Hospital Isolates

Background/aim: Hospital infections are among the most prominent medical problems around the world. Using proper biocides in an appropriate way is critically important in overcoming this problem. Several reports have suggested that microorganisms may develop resistance or reduce their susceptibility to biocides, similar to the case with antibiotics. In this study we aimed to determine the antimicrobial activity of chlorhexidine digluconate against clinical isolates. Materials and methods: The susceptibility of 120 hospital isolated strains of 7 bacterial genera against chlorhexidine digluconate was determined by agar dilution test, using minimum inhibitory concentration (MIC) values and the EN 1040 Basic Bactericidal Activity Test to determine the bactericidal activity. According to MIC values, Pseudomonas aeruginosa and Stenotrophomonas maltophilia were found to be less susceptible to chlorhexidine digluconate. Results: Quantitative suspension test results showed that 4% chlorhexidine digluconate was effective against antibiotic resistant and susceptible bacteria after 5 min of contact time and can be safely used in our hospital. However, concentrations below 4% chlorhexidine digluconate caused a decrease in bactericidal activity, especially for Staphylococcus aureus and P. aeruginosa. Conclusion: It is crucial to use biocides at appropriate concentrations and to perform surveillance studies to trace resistance or low susceptibility patterns of S. aureus, P. aeruginosa, and other hospital isolates.WoSScopu

A Fully Microfabricated Electrochemical Sensor and its Implementation for Detection of Methicillin Resistance in Staphylococcus aureus

On-chip detection of biological analytes can enable diagnosis at the point of care. Combining the advantages of microelectromechanical system (MEMS) technology and molecular methods, we present the design of an integrated microfluidic platform, a microelectrochemical sensor (mu ECS), and its implementation for the detection of methicillin resistance in Staphylococcus aureus. This platform is capable of electrochemically sensing the target analyte in a microfluidic reactor without the usage of bulky electrodes, rendering it useful for in vitro diagnostics. In our experiments, the functionality of the sensor was tested for detecting specific DNA sequences of mecA gene (an indicator of methicillin resistance) over a range of concentrations of DNA (down to 10 pM). Synthetic oligonucleotides and bacterial PCR product were used as a target analyte in Hoechst 33258 marker-based detection and horseradish peroxidase-based detection, respectively. The results revealed that this platform has high sensitivity and selectivity. Also, its compatibility to MEMS processes enables its use with different applications ranging from detecting various types of cancers to endemics. The designed mu ECS can enable the detection of biological analytes of interest at low cost and high throughput

Epidemiology, Clinical and Microbiological Characteristics of Invasive Streptococcal Infections in Turkey, 2010-2011

A one-year active surveillance study was conducted to investigate the epidemiological and microbiological characteristics of invasive group A streptococci (GAS) infections in Turkey and to provide data for the establishment of national preventive strategies related to invasive GAS infections. A total of 46 clinical microbiology laboratories from 12 different regions of Turkey (Istanbul; Eastern and Western Marmara; Eastern and Western Blacksea; Aegean; Mediterranean; Western, Central, Northeastern, Middle-eastern and Southeastern Anatolia) participated in the study. Accordingly, GAS strains isolated from sterile body sites (blood, cerebrospinal, synovial, pleural, peritoneal, pericardial fluids) in the study centers between June 2010-June 2011, were sent to Maltepe University Hospital Clinical Microbiology Laboratory for microbiological confirmation and further analysis. The isolates were identified by conventional methods, and for serotyping, opacity factor (OF) and T protein types were investigated. For genotyping GAS lysate preparation, emm gene amplification and sequencing were performed by using the protocols recommended by Centers for Disease Control and Prevention. A total of 65 invasive GAS strains were isolated in 15 of the participant centers, during the study period. The rate of invasive GAS isolation exhibited regional variation, with the highest rates in the Eastern Blacksea (Trabzon, n=19), followed by Istanbul (n=17) and Western Anatolia (Ankara, Konya, n=14). Of the patients with invasive GAS infection 33 were female, 32 were male, with the age range of 0-89 years. GAS strains were most commonly isolated from soft tissue specimens (n=18), followed by abscess material (n=10), sterile body fluids (n=8) and blood (n=7) samples. Serotyping revealed that 55% (36/65) of the strains were OF positive, and the majority of T protein was polygroup T (n=20), followed by U (n=14), B (n=5), X (n=3) and Y (n=2). T protein was not detected in 22 isolates. The strains were found to have 17 different emm types; emm1 (n=13), emm4 (n=6), emm6 (n=6), emm12 (n=6), emm24 (n=4), emm14 (n=3) and emm28 (n=3). Nine of the strains could not be typed by sequencing. The correlation between emm typing and serotyping was detected as 58%. It was observed that 26-valent vaccines included 70.5% of the invasive GAS strains included in this study. Our study provided initial data concerning the epidemiological properties of invasive GAS infections and characterization of GAS strains in Turkey. The incidence of invasive GAS infections is low in our country. Although immunization programme by 26-valent GAS vaccine is not currently an urgent public health issue for our country, the results of this study indicated that emm types 4 and 24 should better be included in such a vaccine to be used in Turkey. Additionally, since epidemiological features of GAS infections and the microbiological characteristics of the strains can vary by time, for the diagnosis of invasive streptococcal infections and to take the necessary preventive measures, epidemiological studies should be conducted repeatedly

Epidemiology, clinical and microbiological characteristics of invasive streptococcal infections in Turkey, 2010-2011

Bu çalışmada, ülkemizdeki invazif A grubu streptokok (AGS) enfeksiyonlarının epidemiyolojik ve mikrobiyolojik özelliklerinin belirlenmesi ve bu hastalıkların önlenmesinde uygulanacak olan ulusal stratejilere veri sağlanması amacıyla bir yıllık aktif sürveyans yapılması planlanmıştır. Çalışmaya, Türkiye’nin 12 farklı bölgesinden (İstanbul; Doğu ve Batı Marmara; Doğu ve Batı Karadeniz; Ege; Akdeniz; Batı, Orta, Kuzeydoğu, Ortadoğu ve Güneydoğu Anadolu) toplam 46 klinik mikrobiyoloji laboratuvarı katılmıştır. Katılımcı merkezlerde, Haziran 2010-Haziran 2011 tarihleri arasında steril vücut bölgelerinden (kan, beyin omurilik sıvısı, eklem, plevra, periton, perikard sıvıları) izole edilen AGS’ler, doğrulama ve ileri çalışmalar için Maltepe Üniversitesi Tıp Fakültesi, Tıbbi Mikrobiyoloji Anabilim Dalı Laboratuvarına gönderilmiştir. Bakterilerin tanımlanması konvansiyonel yöntemlerle yapılmış; serotiplendirme için opasite faktörü (OF) ve T protein tipleri araştırılmış, genotiplendirme için AGS lizatı hazırlama, emm geni amplifikasyonu ve dizilenmesi, “Centers for Disease Control and Prevention” protokolüne göre uygulanmıştır. Çalışma dönemi içinde katılımcı merkezlerin 15’inden, 65 invazif AGS suşu izole edilmiştir. İnvazif AGS izolasyon oranının bölgesel farklılıklar gösterdiği belirlenmiş, en yüksek izolasyonun Doğu Karadeniz (Trabzon; n= 19) bölgesinde olduğu, bunu İstanbul (n= 17) ve Batı Anadolu (Ankara, Konya; n= 14) bölgelerinin izlediği görülmüştür. İnvazif AGS enfeksiyonu tanısı konulan hastaların 33’ü kadın, 32’si erkek olup, yaş aralığı 0-89 yıl arasındadır. AGS suşlarının en fazla yumuşak doku (n= 18), apse (n= 10), steril vücut sıvısı (n= 8) ve kan (n= 7) örneklerinden izole edildiği gözlenmiştir. Serotiplendirme sonucunda 36 (%55) izolatın OF pozitif olduğu saptanmış; en sık saptanan T protein tipleri poligrup T (n= 20) ve U (n= 14) olmuş, bunları B (n= 5), X (n= 3) ve Y (n= 2) izlemiştir. Yirmi iki izolatta T proteini tespit edilememiştir. Genotiplendirme sonucunda izolatların 17 farklı emm tipine sahip olduğu saptanmış; en sık rastlanan tipler; emm1 (n= 13), emm4 (n= 6), emm6 (n= 6), emm12 (n= 6), emm24 (n= 4), emm14 (n= 3) ve emm28 6 (n= 3) olarak belirlenmiş, dokuz suş dizileme ile tiplendirilememiştir. İzolatların emm tipleri ile serotipleri arasındaki korelasyon %58 olarak bulunmuştur. Kullanımdaki 26 değerli aşının invazif AGS suşlarının %70.5’ini kapsadığı tespit edilmiştir. Sonuç olarak bu çalışmayla Türkiye’de invaziv AGS enfeksiyonlarının epidemiyolojik ve mikrobiyolojik özellikleriyle ilgili ilk veriler elde edilmiştir. İnvazif AGS enfeksiyon sıklığının ülkemizde düşük olduğu, 26 değerli ASG aşısının aşı programına dahil edilmesinin ülkemiz için şu anda acil halk sağlığı sorunu olmadığı ve eğer ülkemizde kullanılacaksa aşıya emm4 ve emm24 tiplerinin de eklenmesi gerektiği ortaya çıkmıştır.A one-year active surveillance study was conducted to investigate the epidemiological and microbiological characteristics of invasive group A streptococci (GAS) infections in Turkey and to provide data for the establishment of national preventive strategies related to invasive GAS infections. A total of 46 clinical microbiology laboratories from 12 different regions of Turkey (Istanbul; Eastern and Western Marmara; Eastern and Western Blacksea; Aegean; Mediterranean; Western, Central, Northeastern, Middle-eastern and Southeastern Anatolia) participated in the study. Accordingly, GAS strains isolated from sterile body sites (blood, cerebrospinal, synovial, pleural, peritoneal, pericardial fluids) in the study centers between June 2010-June 2011, were sent to Maltepe University Hospital Clinical Microbiology Laboratory for microbiological confirmation and further analysis. The isolates were identified by con- ventional methods, and for serotyping, opacity factor (OF) and T protein types were investigated. For genotyping GAS lysate preparation, emm gene amplification and sequencing were performed by using the protocols recommended by Centers for Disease Control and Prevention. A total of 65 invasive GAS strains were isolated in 15 of the participant centers, during the study period. The rate of invasive GAS isolation exhibited regional variation, with the highest rates in the Eastern Blacksea (Trabzon, n= 19), followed by Istanbul (n= 17) and Western Anatolia (Ankara, Konya, n= 14). Of the patients with invasive GAS infection 33 were female, 32 were male, with the age range of 0-89 years. GAS strains were most commonly isolated from soft tissue specimens (n= 18), followed by abscess material (n= 10), sterile body fluids (n= 8) and blood (n= 7) samples. Serotyping revealed that 55% (36/65) of the strains were OF positive, and the majority of T protein was polygroup T (n= 20), followed by U (n= 14), B (n= 5), X (n= 3) and Y (n= 2). T protein was not detected in 22 isolates. The strains were found to have 17 different emm types; emm1 (n= 13), emm4 (n= 6), emm6 (n= 6), emm12 (n= 6), emm24 (n= 4), emm14 (n= 3) 6 and emm28 (n= 3). Nine of the strains could not be typed by sequencing. The correlation between emm typing and serotyping was detected as 58%. It was observed that 26-valent vaccines included 70.5% of the invasive GAS strains included in this study. Our study provided initial data concerning the epidemio- logical properties of invasive GAS infections and characterization of GAS strains in Turkey. The incidence of invasive GAS infections is low in our country. Although immunization programme by 26-valent GAS vaccine is not currently an urgent public health issue for our country, the results of this study indicated that emm types 4 and 24 should better be included in such a vaccine to be used in Turkey. Additionally, since epidemiological features of GAS infections and the microbiological characteristics of the strains can vary by time, for the diagnosis of invasive streptococcal infections and to take the necessary preventive measures, epidemiological studies should be conducted repeatedly

Antimicrobial resistance in Gram-negative hospital isolates: Results of the Turkish HITIT-2 surveillance study of 2007

Resistance rates to amikacin, ciprofloxacin, ceftazidime, cefepime, imipenem, cefoperazone/sulbactam and piperacillin/tazobactam in Escherichia coli (n = 438), Klebsiella pneumoniae (n = 444), Pseudomonas aeruginosa (n = 210) and Acinetobacter baumanni (n =200) were determined with E-test in a multicenter surveillance study (HITIT-2) in 2007. ESBL production in Escherichia coli and K. pneumoniae was investigated following the CLSI guidelines. Overall 42.0% of E.coli and 41.4% of K. pneumoniae were ESBL producers. In E. coli, resistance to imipenem was not observed, resistance to ciprofloxacin and amikacin was 58.0% and 5.5% respectively. In K. pneumoniae resistance to imipenem, ciprofloxacin and amikacin was 3.1%, 17.8% 12.4% respectively. In P. aeruginosa the lowest rate of resistance was observed with piperacillin/tazobactam (18.1%). A. baumanni isolates were highly resistant to all the antimicrobial agents, the lowest level of resistance was observed against cefoperazone/sulbactam (52.0%) followed by imipenem (55.5%). This study showed that resistance rates to antimicrobials are high in nosocomial isolates and show variations among the centers