Isil Seyis Bilkay

Multi drug resistance in strong biofilm forming clinical isolates of Staphylococcus epidermidis

Staphylococcus epidermidis which exists in healthy human skin as a commensal inhabitant is also an important pathogen forming biofilms on many surfaces and recently, increased resistance traits were suggested to be acquired in biofilm environments. In this study; clinical Prevalences, antibiotic resistances and biofilm formations of S. epidermidis strains were determined and comparison of all these findings with each other was carried out in order to take precautions against them and figure out if high biofilm forming S. epidermidis strains display multi drug resistance. According to our results; samples of wound and blood were the most S. epidermidis isolated clinical materials (40%; 35%) and cardiothoracic surgery was the most S. epidermidis observed service unit. All of these strains were sensitive to vancomycin, however 65% of them showed resistance to all β-lactam antibiotics (Penicillin, Oxacillin, Amoxicilin/Clavulonic acid), used in this study and 60% of all S. epidermidis strains were found as multi drug resistant. When the results of strong biofilm forming S. epidermidis strains are examined; they were isolated from sample of blood and service unit of cardiovascular surgery in highest frequency and 80% of them were β-lactam resistant whereas 100% of them were multi drug resistant. One of these multi drug resistant strains which was resistant to maximum amount of different antimicrobial classes, was also observed as maximum biofilm forming strain among all the other S. epidermidis isolates. Multi drug resistance in strong biofilm forming strains shows that; biofilms play a role in antimicrobial resistance traits of S. epidermidis.

Application of RAPD-PCR for Determining the Clonality of Methicillin Resistant Staphylococcus aureus Isolated from Different Hospitals

Randomly amplified polymorphic DNA (RAPD)-PCR was applied with ten random 10-mer primers to examine the molecular diversity among methicillin resistant Staphylococcus aureus (MRSA) strains in the hospitals and to investigate the epidemiological spread of these strains between different hospitals. The main objective of the study was to identify appropriate primers, which successfully established the clonality of MRSA. Three of the primers yielded particularly discriminatory patterns and they were used to perform the RAPD analysis which revealed different bands ranging from 200 to 1500 bp. Dendogram was created by the un-weighted pair group method using arithmetic (UPGMA) average clustering and it was constructed based on the combination results of the new primers (S224, S232 and S395) which represented a novel approach for rapid screening of the strains and also provided the opportunity for monitoring the emergence and determining clonal dissemination of MRSA strains between the hospitals. Dendogram generated two main groups (Group I and II) with three clusters (A, B and C) and indicated that the strains isolated from the same hospital were closely related and they placed together in the same group. This technique could be of attractive use in controlling the sources and routes of transmission, tracking the spread of strains within hospital and between the hospitals, and especially preventing the nosocomial infections caused by the MRSA.

Anti-biofilm effect of nanometer scale silver (NmSAg) coatings on glass and polystyrene surfaces against P. mirabilis, C. glabrata and C. tropicalis strains.

Purpose Nowadays, in order to terminate biofilm associated infections, coating of particular biomaterial surfaces with particular substances, via some nanotechnological tools, is being applied. Therefore, in the present study, investigation of anti-biofilm effects of nanometer scale silver (NmSAg) coatings on glass and polystyrene surfaces against clinical strains of Proteus mirabilis, Candida glabrata and Candida tropicalis was aimed. Methods In this study, glass and polystyrene slabs with 1.5 cm × 1.5 cm × 0.3 mm dimensions were cleaned by using surface plasma technology, covered with NmSAg by using a physical vapor deposition machine, and biofilm inhibition was determined by crystal violet binding assay. Results According to our results, 32 nm of silver layer on a glass slab decreased biofilm formation of P. mirabilis strain to a maximum amount of 88.1% and caused 20.9% inhibition in biofilm formation of C. glabrata strain. On the other hand, NmS coating of Ag on a polystyrene slab caused 34.4% and 20% inhibitions, respectively, in biofilm formations of C. glabrata and C. tropicalis strains. Although biofilm inhibition of NmSAg layer on polystyrene slab was more (34.4%) than biofilm inhibition caused by NmSAg layer on glass slab (20.9%), C. glabrata strains biofilm formation on uncoated glass slab was lower than both uncoated and NmSAg-coated polystyrene slabs. Conclusions Our results show that glass surfaces with NmSAg coatings can be used as a new surface material of various indwelling devices on which P. mirabilis colonizations frequently occur and in order to avoid C. glabrata-associated biofilm infections, it is more useful to choose a surface material of glass rather than choosing a surface material of polystyrene.

Biological Treatment of Cyanide by Using Klebsiella pneumoniae Species

In this study, optimization conditions for cyanide biodegradation by Klebsiella pneumoniae strain were determined to be 25 °C, pH=7 and 150 rpm at the concentration of 0.5 mM potassium cyanide in the medium. Additionally, it was found that K. pneumoniae strain is not only able to degrade potassium cyanide, but also to degrade potassium hexacyanoferrate(II) trihydrate and sodium ferrocyanide decahydrate with the efficiencies of 85 and 87.5%, respectively. Furthermore, this strain degraded potassium cyanide in the presence of different ions such as magnesium, nickel, cobalt, iron, chromium, arsenic and zinc, in variable concentrations (0.1, 0.25 and 0.5 mM) and as a result the amount of the bacteria in the biodegradation media decreased with the increase of ion concentration. Lastly, it was also observed that sterile crude extract of K. pneumoniae strain degraded potassium cyanide on the fifth day of incubation. Based on these results, it is concluded that both culture and sterile crude extract of K. pnemoniae will be used in cyanide removal from different wastes.

Distribution of clinical isolates of Candida spp. and antifungal susceptibility of high biofilm-forming Candida isolates

INTRODUCTION The increase in the incidence of fungal infections, especially those caused by Candida albicans and other Candida species, necessitates the understanding and treatment of Candida-associated infections. In this study, we aimed to investigate the identification, distribution, and biofilm formation ability of different clinical Candida isolates and evaluate the distribution and antifungal susceptibilities of high biofilm-forming (HBF) Candida isolates. METHODS For identification, carbohydrate fermentation, carbohydrate assimilation, and ChromAgar tests were used. Biofilm formation was assessed using crystal violet binding assay, while the susceptibility to antifungal agents was determined using ATBTM Fungus 3 test kits. RESULTS The majority of Candida species were C. parapsilosis (31.3%; 31/99) and C. tropicalis (30.3%; 30/99). C. tropicalis was found to be the most frequently isolated species among all HBF Candida species. HBF Candida isolates were more frequently isolated from vaginal swab (35.7%; 10/28), tracheal aspirate (17.9%; 5/28), and urine (17.9%; 5/28). The majority of tested isolates were resistant to itraconazole and voriconazole, whereas no isolate was deemed resistant to 5-flucytosine. CONCLUSIONS C. tropicalis displays the highest biofilm formation ability among all the Candida species evaluated, and HBF Candida isolates were more frequently seen in vaginal swab, tracheal aspirate, and urine samples. Our findings revealed that 5-flucytosine is the most efficient antifungal agent against HBF Candida isolates.

Determination of petroleum biodegradation by bacteria isolated from drilling fluid, waste mud pit and crude oil

Objective: In this study, the aim was to isolate and identify bacterial strains in crude oil, drilling fluid and waste mud pit samples collected from the same oil field, determine the petroleum biodegradation and find the most effective bacteria in the samples in petroleum biodegradation. Methods: The contents of crude oil, drilling fluid and waste mud pit samples were enriched in appropriate conditions. Upon identification of the isolated bacteria, the incubations in petroleum containing media were performed at 150 rpm at 30°C for 7 days. Petroleum biodegradations by bacteria were measured by using colorimetric, spectrophotometric and gravimetric methods. Results: Bacillus cereus, Proteus mirabilis, Bacillus subtilis, Enterococcus faecalis were isolated from the crude oil sample; Bacillus subtilis subsp. spizizenii, Bacillus cereus, Enterococcus faecalis were isolated from the waste mud pit; and Proteus mirabilis, Klebsiella pneumoniae, Bacillus tequilensis, Bacillus axarquiensis and Enterobacter cloacae were isolated from the drilling fluid. Klebsiella pneumoniae was found to degrade 60% of the petroleum in the media and Bacillus axarquiensis degraded 51%. Conclusion: In literature, no study was encountered showing biodegradation efficiencies of Bacillus axarquiensis which was isolated from the drilling fluid in our study. The use of Bacillus axarquiensis can contribute to advanced bioremediation studies.

Investigation of lactose hydrolysis by crude extract of Trichoderma viride ATCC 32098

Abstract Objective: Aim of this study was to find the optimum pH, temperature and incubation conditions for efficient lactose hydrolysis by beta-galactosidase produced by Trichoderma viride ATCC 32098. In addition, enzymatic lactose hydrolysis in milk, whey and lactose solutions were studied and compared. Material and methods: Trichoderma viride ATCC 32098 was incubated at 30°C for 8 days on a rotary shaker. Lactose hydrolysis was calculated based on the amount of glucose measured. Hydrolysis was carried out in lactose solution, milk and whey. Results: Maximum efficiency was observed at pH 5.0 and at 60°C. Agitation increases lactose hydrolysis slightly. When enzymatic lactose hydrolysis in milk, whey and lactose solutions were studied, it was observed that after 26 h, hydrolyses in lactose solution and whey were almost 100% and hydrolysis in milk was 92%. Conclusion: It can be concluded that the enzyme produced from T. viride ATCC 32098 in this study is a good alternative for use in lactose hydrolysis.

Investigation of Antimicrobial Activity of Pyocyanin Produced by Pseudomonas aeruginosa Strains Isolated from Different Clinical Specimens

Pseudomonas aeruginosa suşları tarafından üretilen piyosiyanin karakteristik mavi-yeşil bir fenazin pigmentidir. Çalışmanın amacı, P. aeruginosa suşlarında en yüksek piyosiyanin üretiminin belirlenmesi ve piyosiyaninin Escherichia coli, Bacillus sp., Pseudomonas aeruginosa, Candida sp. and Aspergillus niger üzerindeki antimiktobiyal etkisinin araştırılmasıdır. Bu doğrultuda, piyosiyanin P. aeruginosa kültür süpernatanından özütlendi ve saflaştırıldı, ardından spektrofotometrik olarak ölçüldü. En yüksek piyosiyanin üretiminin idrar örneğinden izole edilen P. aeruginosa A10 suşunda ve en düşük piyosiyanin üretiminin batından izole edilen P. aeruginosa A1 suşunda olduğu belirlendi. Piyosiyaninin antimikrobiyal etkisinin belirlenmesinde ‘Agar Kuyu Difüzyon’ yöntemi uygulandı. Böylece, piyosiyanin Bacillus sp., Escherichia coli ve Candida sp., üzerinde etkili bir antimikrobiyal ajanken, P. aeruginosa ve A. niger üzerinde antimikrobiyal etkisi görülmedi. Ardından, agar kuyu yöntemi ile piyosiyanine duyarlı olduğu belirlenen suşlara ‘Tüp Seyreltme Yöntemi’ kullanıldı. Azalan piyosiyanin derişimleri ile Bacillus sp. and Candida sp. suşlarının üremesinde artış gözlendi.

ANTIBIOFILM EFFECTS of Citrus limonum and Zingiber officinale Oils on BIOFILM FORMATION of Klebsiella ornithinolytica, Klebsiella oxytoca and Klebsiella terrigena SPECIES

Background: Microbial cells growing in biofilms, play a huge role in the spread of antimicrobial resistance. In this study, biofilm formation of Klebsiella strains belonging to 3 different Klebsiella species (K. ornithinolytica, K. oxytoca and K. terrigena), cooccurences’ effect on biofilm formation amount and anti-biofilm effects of Citrus limon and Zingiber officinale essential oils on biofilm formations of highest biofilm forming K. ornithinolytica, K. oxytoca and K. terrigena strains were determined. Materials and Methods: Anti-biofilm effects of Citrus limon and Zingiber officinale essential oils on biofilm formations of highest biofilm forming K. ornithinolytica, K. oxytoca and K. terrigena strains were investigated. Results: 57% of K. ornithinolytica strains and 50% of K. oxytoca strains were found as Strong Biofilm Forming (SBF), there wasn’t any SBF strain in K. terrigena species. In addition to this, clinical materials of urine and sperm were found as the most frequent clinical materials for strong biofilm forming K. ornithinolytica and K. oxytoca isolations respectively (63%; 100%) Secondly, all K. ornithinolytica strains isolated from surgical intensive care unit and all K. oxytoca strains isolated from service units of urology were found as SBF. Apart from these, although the amount of biofilm, formed by co-occurence of K. ornithinolytica - K. oxytoca and K. oxytoca - K. terrigena were more than the amount ofbiofilm formed by themselves separately, biofilm formation amount of co-occurrence of K. ornitholytica - K. terrigena strains was lower than biofilm formation amount of K. ornithinolytica but higher than biofilm formation amount of K. terrigena. Conclusion: The antibiofilm effects of Citrus limonum and Zingiber officinale essential oils could be used against biofilm Klebsiella aquired infections.

Comparative assessment of five clinical Klebsiella isolates in terms of antibiotic resistance and plasmid profiles / Beş farklı klinik Klebsiella türünün antibiyotik dirençliliği ile plazmid profillerinin karşılaştırmalı olarak değerlendirilmesi

Abstract Objective: This study is firstly aimed to biotype and to investigate the antibiotic resistance profiles of Klebsiella strains which were isolated from clinical materials. Also plasmid profile types of Klebsiella species were investigated and the results were compared with each other. Methods: Klebsiella strains were biotyped by BBL Enterotube II and the antibiotic resistance was tested by Kirby Bauer disc diffusion method. In order to analyse Klebsiella strains genotypically, plasmid DNA’s of them were isolated and generated plasmid profile types determined by Dice coefficients of similarity. Results: According to biotyping, Klebsiella strains were distributed to five different species (K. pneumoniae, K. ornithinolytica, K. oxytoca, K. terrigena, K. rhinoscleromatis). As well as K. pneumoniae (37.33%) was the most isolated strain, K. terrigena (8.95%) which is not found to be investigated as much as other strains in the literature, was also observed. Additionally, it is determined that Klebsiella strains were resistant to at least one and at most seven antibiotics. With a similarity coefficient of 84%, it was observed that five different Klebsiella species displayed 17 different plasmid profile types. Among these profiles, P1 (52.23%) was the most observed type which exhibits >10 kbp plasmid DNA band and this profile was isolated from all strains. Conclusion: Finally, it is observed that antibiotic resistance can be due to the plasmid or chromosomal sources and different strains of the same genus may exhibit the same plasmid profile because of the plasmid transformation from one strain to another. Özet Amaç: Bu çalışma öncelikle klinik materyallerden izole edilen Klebsiella türlerinin biyotiplendirilmesi ve antibiyotik direnç profillerinin belirlenmesini amaçlamaktadır. Bunun yanı sıra çalışmamızda Klebsiella türlerinin plazmid profilleri incelenmiş ve antibiyotik direnç profilleri ile karşılaştırılarak yorumlanmıştır. Metod: Klebsiella türleri BBL Enterotube II kullanılarak biyotiplemesi yapıldı ve antibiyotik dirençlilikleri Kirby Bauer disk difüzyon metodu kullanılarak test edildi. Klebsiella suşlarının genotipik olarak analiz edilmesi için söz konusu türlerin plazmid DNA’ları izole edildi ve oluşturulan plazmid tipleri benzerlik katsayısı kullanılarak belirlendi. Bulgular: Biyotipleme sonuçlarına göre Klebsiella türlerinin 5 farklı türe (K. pneumoniae, K. ornithinolytica, K. oxytoca, K. terrigena, K. rhinoscleromatis) ayrıldığı belirlendi. K. pneumoniae (%37.33) türünün en fazla izole edilen tür olduğu, aynı zamanda literatürde diğer Klebsiella türlerine kıyasla daha az çalışılmış olan K. terrigena’nın (%8.95) da çalışmamızda izole edildiği gözlendi. Ayrıca, Klebsiella türlerinin en az 1 en fazla 7 antibiyotiğe dirençli oldukları belirlendi. 5 farklı Klebsiella türünün %84 benzerlik katsayısı ile 17 farklı plazmid profil tipine ayrıldığı saptandı. Bu profiller içerisinde >10 kbç plasmid DNA bantı içeren P1 (%52.23) plazmid profil tipinin Klebsiella türlerinin hepsinde en fazla izole edilen tip olduğu belirbelirlendi. Sonuç: Sonuç olarak, antibiyotik direncinin plazmid veya kromozomal kaynaklı olabileceği ve aynı cins içerisinde yer alan farklı türlerin, bir türden diğer türe aktarılan plazmidler nedeniyle aynı plazmid profil tipini gösterebileceği saptandı.