The emergence of Klebsiella pneumoniae sequence type 395 non-susceptible to carbapenems and colistin from Turkey

PURPOSE

OXA-48 producing Klebsiella pneumoniae is an emerging threat and outbreaks due to specific sequence types have been commonly reported. Here, we report an outbreak due to multidrug-resistant ST395 K. pneumoniae ST395. To the best of our knowledge, this is the first outbreak of K. pneumoniae ST395 harbouring blaOXA-48 genes in our country.

METHODS

The strains were characterized by antimicrobial susceptibility, extended-spectrum β-lactamase (ESBL) and carbapenemase production, plasmid-mediated colistin, high-level aminoglycoside, and quinolone resistance. Also multidrug efflux pumps and porin coding genes were investigated. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), wzi typing and plasmid analysis were used for the epidemiological relationships.

RESULTS

All strains were positive for blaOXA-48 with at least one of the β-lactamase genes (blaCTX-M, blaTEM, blaSHV) and harboured IncL plasmids. 16 of 20 (80%) isolates carried qnrA. All isolates were positive for aac(6')-1b, acrAB-tolC, ompK35, and ompK36 genes but none of them harboured 16s rRNA methyltransferase, mcr-1-5, qepA, oqxAB, and mdtK genes. All strains had the same PFGE pattern, that is, wzi type K2 and found to be ST395 with MLST.

CONCLUSION

The association of ST395 with OXA-48-producers could be an emerging threat for Turkey and continuous monitoring is crucial to prevent the spread of these powerful strains.

[Investigation of Virulence Factors, Phylogenetic Group Features, and the Presence of ST131 Clone in Escherichia coli Isolates, a Urinary Tract Infection Agent in Children]

Urinary tract infection (UTI) caused by Escherichia coli is a significant health issue in children. Today especially E.coli O25b/ST131, defined as a pandemic clone, is a serious public health problem due to its high virulence and antimicrobial resistance rates. In this study, a total of 200 (100 first and 100 recurrent UTI-causing) E.coli isolates from urine samples sent to the Ankara University School of Medicine Cebeci Training and Research Hospital Central Laboratory between January and September 2021 with the preliminary diagnosis of UTI in pediatric patients aged three to 18 years were analyzed for antimicrobial resistance rates, phylogenetic group distributions, virulence factor frequencies and whether they belong to the O25b/ST131 clone. It is aimed in this study that, the obtained data will shed light on new studies for diagnosis, treatment and prophylaxis options that can be developed for more effective UTI management by contributing to the surveillance studies in our country. Antimicrobial susceptibility of E.coli isolates identified by conventional methods was evaluated by Kirby-Bauer disc diffusion method and extended spectrum beta-lactamase (ESBL) production was evaluated by double disc synergy test. Polymerase chain reaction (PCR) was used for the investigation of phylogenetic grouping, the O25b/ST131 clone, virulence genes and the molecular level classification of the isolates detected as uropathogenic E.coli (UPEC). Pulsed-field gel electrophoresis (PFGE) was performed with the isolates collected at different times from the same patient. The highest antimicrobial resistance rates observed were against ampicillin (n= 100, 50%), cefazolin (n= 99, 49.5%), trimethoprim-sulfamethoxazole (n= 55, 27.5%), amoxicillin-clavulanic acid (n= 43, 21.5%) and cefotaxime (n= 43, 21.5%). In recurrent UTI agents, resistance rates were higher for cefotaxime (n= 29, 29%), trimethoprim-sulfamethoxazole (n= 35, 35%) and cefepime (n= 25, 25%) and in O25b/ST131 isolates (n= 67) the rates were higher for amikacin (n= 3, 4.5%), gentamicin (n= 10, 14.9%) and ciprofloxacin (n= 17, 25.4%) when compared to the first UTI agents and non-O25b/ ST131 isolates (p< 0.05). It was found that 29% (n = 58) of the isolates were multidrug resistant (MDR) and 19% (n = 38) produced ESBL.The rate of recurrent UTI agents was found to be higher among ESBL producing isolates and/or MDR isolates (n= 36, 62% and n= 27, 71%, respectively, p< 0.05). It was found that 45.5% (n= 91) of the isolates were in D, 37.5% (n= 75) in B2, 12.5% (n= 25) in A, and 4.5% (n= 9) in B1 phylogenetic groups and isolates belonging to B2 and D phylogenetic groups had higher antibiotic resistance rates and carried more virulence genes (p< 0.05). Of the isolates, 33.5% (n= 67) were found to belong to the O25b/ST131 clone, no significant difference was found between the O25b/ST131 rates among the first and recurrent UTI agents (p> 0.05). It was determined that the isolates most frequently carry virulence genes for adhesion [fimH 97% (n= 194), papA 57% (n= 114), yfcV 49.5% (n= 99)] and iron uptake systems [fyuA 85.5% (n= 171), chuA 78% (n= 156), iutA 73% (n= 146)]. All virulence factors were detected more frequently in isolates belonging to the O25b/ST131 clone (p< 0.05). Of the isolates, 97% (n= 65) belonging to the O25b/ST131 clone and 27.1% (n= 36) not belonging to this clone were defined as UPEC with molecular analysis (p< 0.0001). Thirty-three isolates belonging to 15 patients were evaluated with PFGE, and it was observed that the latter isolate and the first isolate of eight patients (53%) had the same band profile. Focusing on surveillance, diagnostic testing, treatment algorithms, and preventive measures for E.coli and especially for ST131 clone, which is frequently observed as causative agent in childhood UTIs, will help to manage challenging E.coli infections.

Investigation of the presence of Capnophilic bacteria in routine urine cultures

Capnophilic Escherichia coli (CEC) strains are rarely isolated from urinary tract infections (UTIs). The purpose of this research was to look into the incidence and traits of the CEC strains that cause UTIs. Nine (0.11%) epidemiologically unrelated CEC isolates with varying antibiotic susceptibility patterns were identified from patients with various co-morbidities after the evaluation of 8500 urine samples. Three of these strains belonged to the O25b-ST131 clone, and none of them possessed the yadF gene. Due to adverse incubation conditions, CEC isolation is difficult. Although rare, capnophilic incubation of urine cultures may be considered particularly for patients with underlying predisposing conditions.

Wohlfahrtiimonas chitiniclastica-related soft-tissue infection and osteomyelitis: A rare case report

Wohlfahrtiimonas chitiniclastica is a rare pathogen that was first isolated from Wohlfahrtia magnifica, a parasitic fly. It is an uncommon, but an emerging human pathogen reported only in Europe and South America. Until today, it has been reported to be a zoonotic pathogen originating from different geographic locations. The present case, a patient suffering from osteomyelitis in Turkey, represents the first report of this pathogen in this country and so far no reports of related osteomyelitis associated with W. chitiniclastica is available. Clin-ical awareness of these emerging human pathogens is crucial for controlling infectious diseases.

Colour agreement between try-in paste and resin cement: effect of background on zirconia-reinforced lithium silicate

PURPOSE

To investigate colour agreement between different shades of Panavia V5 resin cement and their try-in pastes under zirconia-reinforced lithium silicate ceramics.

METHODS

Forty-four zirconia-reinforced lithium silicate ceramic specimens were prepared at 0.8 ± 0.01 mm thickness. Composite resin tooth-shaded background specimens were obtained in two shades. Resin cement specimens were fabricated at 0.1-mm thickness. Colour difference values (ΔE) between Aquagel and both the try-in paste and resin cement were calculated using the CIE-Lab system. The CIEDE2000 (ΔE00) colour formula was used to determine colour differences. The three-way ANOVA test and a multiple comparisons test were used for statistical analysis (α = 0.05).

RESULTS

A statistically significant difference was found between the ΔE00 values obtained from the cement shade colour measurements for all specimens (P < 0.05). According to the three-way ANOVA test, lower ΔE00 values were observed in the try-in paste group compared to the resin cement group. The ΔE00 values were significantly affected by the cement shade and tooth-shaded background (P < 0.05).

CONCLUSIONS

The colour agreement between the try-in pastes and the corresponding resin cement differed, and the try-in pastes could not mask the dark dental background as much as the corresponding resin cement.

Prospective Analysis of Hemorrhagic Cystitis and BK Viremia in Allogeneic Hematopoietic Stem Cell Transplantation

Objective

BK virus (BKV) infection has been shown to be related to hemorrhagic cystitis (HC) in allogeneic hematopoietic stem cell transplantation (allo-HSCT). There are conflicting data regarding the association between BKV titers in plasma and clinical disease as well as the risk factors for BKV-related HC. Our aim is to study the risk factors and relationship with plasma BK viral load for development of HC in a prospective analysis.

Materials and Methods

We prospectively evaluated 59 patients who received allo-HSCT between 2014 and 2016 by quantitative BK virus polymerase chain reaction (PCR) (Altona Diagnostics, Germany) from blood samples at days 0, 30, 60, and 90 after allo-HSCT. The patients were monitored for signs and symptoms of HC.

Results

HC was diagnosed in 22 patients (37%) at a mean of 100 days (range: 0-367 days). In multivariate analysis, the usage of cyclophosphamide (sub-distribution hazard ratio [sdHR]: 7.82, confidence interval [CI]: 1.375-39.645, p=0.02), reactivated CMV (sdHR: 6.105, CI: 1.614-23.094, p=0.008), and positive BKV viremia (sdHR: 2.15, CI: 1.456-22.065, p=0.01) significantly increased the risk of developing HC. Patients with higher viral loads at day 30 and day 60 were diagnosed with more severe HC (p<0.001). Median BK viral loads of >101.5 copies/mL at day 0 (sensitivity 0.727, specificity 0.875), >98.5 copies/mL at day 30 (sensitivity 0.909, specificity 0.875), and >90.0 copies/mL at day 60 (sensitivity 0.909, specificity 0.875) were indicative of HC.

Conclusion

Our study showed that administration of cyclophosphamide, CMV reactivation, and BK virus positivity were associated with HC. Plasma BK virus PCR titers at days 0, 30, and 60 after transplant were sensitive tools for predicting clinically proven HC.

Detection of sasX Gene and Distribution of SCCmec Types in Invasive and Non-invasive Coagulase-negative Staphylococci

Background

Coagulase-negative staphylococci, which belong to the normal microbiota of the skin and mucous membranes, are opportunistic pathogens. sasX, a newly described protein, is thought to play an important role in nasal colonization and methicillin-resistant Staphylococcus aureus virulence, and it may be acquired from coagulase-negative staphylococci by horizontal gene transfer. It has been considered that understanding the function of sasX gene may help clarify the relevance of the different adhesion mechanisms in the pathogenesis of infections associated with biofilm.

Aims

To investigate the sasX gene presence, staphylococcal cassette chromosome mec types, and antimicrobial resistance patterns of invasive and noninvasive coagulase-negative staphylococci isolates.

Study Design

Cross-sectional study.

Methods

The study included a total of 180 coagulase-negative staphylococci strains. Non-invasive isolates (n=91) were obtained from the hands of healthy volunteers who do not work at the hospital (n=30), the nasal vestibule of healthy volunteer hospital workers (n=26), and central venous catheter (n=35). Invasive isolates (n=89) were isolated from peripheral blood cultures of inpatients who do not have catheters. All isolates were identified by conventional microbiological methods, automated systems, and, if needed, with matrix-assisted laser desorption/ionization-time of flight. Staphylococcal cassette chromosome mec typing, sasX and mec gene detection, antibiotic susceptibility, and sasX gene sequence analysis were performed.

Results

Peripheral blood, central venous catheter colonization, and nasal vestibule isolates were positive for the sasX gene, whereas hand isolates were negative. sasX gene was present in 17 isolates, and no statistical significance was found between invasive and noninvasive isolates (p=0.173). Sequence analysis of the sasX genes showed high homology to related proteins of Staphylococcus phage SPbeta-like and Staphylococcus epidermidis RP62A. staphylococcal cassette chromosome mec type V was the most prevalent regardless of species. staphylococcal cassette chromosome mec type II was more frequent in invasive isolates and found to be statistically important for invasive and noninvasive S. epidermidis isolates (p=0.029). Staphylococcus haemolyticus isolates had the overall highest resistance rates. Resistance to ciprofloxacin, trimethoprim-sulfamethoxazole, and erythromycin was found to be higher in isolates from catheter and blood culture. Staphylococcus hominis isolates had the highest rate for inducible clindamycin resistance. None of the isolates were resistant to vancomycin, teicoplanin, and linezolid.

Conclusion

The sasX gene is detected in 9.44% of the isolates. There is no statistical difference between the sasX-positive and -negative isolates in terms of antibacterial resistance and the presence of sasX and SCCmec types. Further studies about the role of sasX at virulence in coagulase-negative staphylococci, especially from clinical samples such as tracheal aspirate and abscess isolates, and distribution of staphylococcal cassette chromosome mec types are needed.

Evaluation of the Presence and Characterization of Vancomycin-Intermediate and Heterogeneous Vancomycin-Intermediate Level Resistance Among Bloodstream Isolates of Methicillin-Resistant Staphylococcus aureus

Aims: Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) could be misinterpreted as "susceptible" with routine susceptibility testing procedures, and the subpopulations with reduced susceptibility to glycopeptides can lead to therapeutic failure. The aim of this study was to evaluate the presence of VISA and hVISA strains among stocked bloodstream methicillin-resistant S. aureus (MRSA) isolates of 14 years. Materials and Methods: A total of 127 nonduplicate MRSA strains isolated from blood cultures between 2001 and 2014 were investigated. Glycopeptide minimum inhibitory concentration values were detected by microbroth dilution method. Susceptibilities to other antimicrobials were determined by the disk diffusion method and interpreted according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. Macrogradient test (MGT) and modified population analysis profile-area under the curve (modified PAP-AUC) methods were used to detect VISA and hVISA. Staphylococcal Cassette Chromosome mec (SCCmec), agr, and toxin gene typing were done by polymerase chain reaction. Genetic relatedness of the strains were evaluated by pulsed-field gel electrophoresis (PFGE). Results: All isolates were susceptible to glycopeptides, linezolid, and quinupristin-dalfopristin. All were resistant to tetracycline, 96% were resistant to aminoglycosides, fluoroquinolones, and rifampin. Only 58.3% of the isolates were susceptible to ceftaroline. Six isolates were suspected as hVISA by the MGT, but none could be confirmed by the modified PAP-AUC analysis. All isolates carried type-III SCCmec, sea was the most prevalent (96.9%) enterotoxin gene and agr group I locus was predominant (93.7%). PFGE analysis revealed four main and four unique patterns. Conclusion: No hVISA or VISA were detected. The resistance rate to ceftaroline seems remarkable due to its recent entry into the market in Turkey.

Viral nucleic acid analysis with PCR in lacrimal tissue and nasal swab samples of primary acquired nasolacrimal duct obstruction cases

PURPOSE

To evaluate the role of viral infections in the pathogenesis of primary acquired nasolacrimal duct obstruction.

METHODS

The study included 48 patients diagnosed with primary acquired nasolacrimal duct obstruction undergoing dacryocystorhinostomy surgery. Prior to dacryocystorhinostomy surgery, nasal swab sample was taken from the inferior meatus at the same side. During dacryocystorhinostomy, tissue biopsy sample (2 × 2 mm) was taken from the junction area of the lacrimal sac and nasolacrimal duct. Following nucleic acid extraction, polymerase chain reaction was performed.

RESULTS

The patients consisted of 9 (18.8%) men and 39 (81.2%) women with a mean age of 51.0 ± 14.3 years. Qualitative polymerase chain reaction showed viral genome in the nasal swabs of 10 (20.8%) patients, including coronavirus 229E (three cases), coronavirus HKU1 (two cases), respiratory syncytial virus (two cases), coronavirus OC43 (one case), coronavirus NL63 (one case), and adenovirus (one case). In the dacryocystorhinostomy samples, viral genomes were detected in four (8.3%) cases, including respiratory syncytial virus (two cases), coronavirus HKU1 (one case), and adenovirus (one case). There was a statistically significant agreement between nasal mucosal swab and dacryocystorhinostomy biopsy samples in terms of respiratory syncytial virus positivity (kappa = 1.000, p = 0.001).

CONCLUSION

Although the viral genome was detected in the samples, a direct relationship between viruses and pathogenesis of primary acquired nasolacrimal duct obstruction could not be revealed because of the low number of positive results. However, considering the profibrotic characteristics of specific viruses such as respiratory syncytial virus and adenovirus, viral infections may be one of the many predisposing factors of primary acquired nasolacrimal duct obstruction.

Upper respiratory viral infections in patients with haematological malignancies after allogeneic haematopoietic stem cell transplantation: a retrospective study

BACKGROUND

Community respiratory viruses (CRVs) are associated with upper respiratory viral infections (URI), pneumonia or life-threatening respiratory disease in patients with allogeneic haematopoietic stem cell transplantation (allo-HSCT). Our aim is to demonstrate our URI experience related to CRVs after allo-HSCT.

METHODS

From January 2013 to November 2015, 39 post allo-HSCT patients with acute URI symptoms were included in the study. We evaluated CRVs by multiplex PCR from nasopharyngeal wash and throat swabs.

RESULTS

The median age of the patients was 39 (range 20-67 years). A total of 25 patients (64%) had viral panel positivity at a median 140 days post-transplant (range 3-617 days). The most common agents detected were respiratory syncytial virus (32%) and parainfluenza (32%). The patients with viral panel positivity had significantly lower lymphocyte count (1.05×10⁹/l versus 3.09×10⁹/l; P=0.013). During follow-up, 20 patients (80%) were diagnosed with pneumonia. Patients with concurrent bacterial or fungal infections were more likely to have pneumonia (100% versus 68%; P=0.023). 10 patients (40%) died due to pneumonia and related complications. Lower lymphocyte counts and higher C-reactive protein levels at the time of viral panel positivity were risk factors for mortality (1.5×10⁹/l versus 0.39×10⁹/l, P=0.007; 74.2 versus 199.7, P=0.006).

CONCLUSIONS

The viral panel was positive in 64% of patients with acute URI symptoms. Lower lymphocyte count was detected in CRV-positive patients. The onset of concomitant bacterial or fungal infections increased the risk of lower respiratory infection disease. Indeed, prospective studies should be designed for risks and outcomes of CRVs in allo-HSCT recipients.

Characterization of Klebsiella pneumoniae Coproducing KPC and NDM-1 Carbapenemases from Turkey

Aims: The emergence of multidrug-resistant and carbapenem-resistant Klebsiella pneumoniae has became a major public health threat. In this study, we describe the characteristics of isolates coproducing KPC and NDM-1 carbapenemases from patients hospitalized at an emergency unit in Ankara, Turkey, between January and August 2018. The isolates were characterized by antibiogram susceptibility, carbapenemase and extended-spectrum beta-lactamase production, plasmid-mediated colistin (COL) resistance, and high-level aminoglycoside resistance. Pulsed field gel electrophoresis (PFGE), sequencing, wzi typing, multilocus sequence typing, and plasmid analysis were used to investigate the epidemiological relationship between the isolates. Results: All isolates were found to be resistant to amoxicillin-clavulanic acid, piperacillin-tazobactam, cefotaxime, cefoxitin, cefuroxime, ceftazidime, cefepime, imipenem, meropenem, ertapenem, amikacin, gentamicin, ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole. The minimum inhibitory concentration values for imipenem, meropenem, and ertapenem were >32 μg/mL, and >256 μg/mL for amikacin and gentamicin, and two isolates were found to be susceptible to both tigecycline and COL. All strains were positive for SHV, CTX-M, and rmtC, and negative for mcr-1 genes. A/C and FIIA_S plasmids were found in all isolates. All isolates had the same PFGE pattern: wzi type 93 and ST15. Conclusion: Here, we have documented the characteristics of KPC- and NDM-1-coproducing isolates that harbored SHV, CTX-M, and rmtC and were typed as wzi 93 and ST15. We conclude that continuous monitoring of carbapenemases for unusual carbapenemase production is crucial to prevent the spread of these powerful isolates.

Evaluation of antimicrobial susceptibilities and virulence factors of Staphylococcus aureus strains isolated from community-acquired and health-care associated pediatric infections

Karbuz A, Karahan ZC, Aldemir-Kocabaş B, Tekeli A, Özdemir H, Güriz H, Gökdemir R, İnce E, Çiftçi E. Evaluation of antimicrobial susceptibilities and virulence factors of Staphylococcus aureus strains isolated from community-acquired and health-care associated pediatric infections. Turk J Pediatr 2017; 59: 395-403. The aim of this study was to investigate the enterotoxins and Panton-Valentine leukocidin (PVL) gene as virulence factor, identification if antimicrobial sensitivity patterns, agr (accessory gene regulator) types and sequence types and in resistant cases to obtain SCCmec (staphylococcal cassette chromosome mec) gene types which will be helpful to decide empirical therapy and future health politics for S. aureus species. Total of 150 isolates of S. aureus were isolated from the cultures of the child patients in January 2011 and December 2012. In this study, the penicillin resistance was observed as 93.8%. PVL and mecA was detected positive in 8.7% and in 6% of all S. aureus strains, respectively. Two MRSA (methicillin resistant S.aureus) strains were detected as SCCmec type III and SCCmec type V and five MRSA strains were detected as SCCmec type IV. SET-I and SET-G were the most common detected enterotoxins. In both community-associated and healthcare-associated MRSA strains, agr type 1 was detected most commonly. The most common sequence types were ST737 in 13 patients than ST22 in eight patients and ST121 in six patients. This study highlights a necessity to review the cause of small changes in the structural genes in order to determine whether it is a cause or outcome; community-acquired and healthcare associated strains overlap.

[Investigation of biofilm formation properties of staphylococcus isolates]

Biofilm production is an important virulence factor which allows staphylococci to adhere to medical devices. The principal component of biofilm is a "polysaccharide intercellular adhesin (PIA)" which is composed of a beta-1,6-N-acetylglucosamine polymer synthesized by an enzyme (N-acetylglucosamine transferase) encoded by the ica operon found on the bacterial chromosome. This operon is composed of four genes (A, B, C, and D), and a transposable element IS256. In this study, we aimed to determine the biofilm production characteristics of invasive/non-invasive staphylococcus isolates and different staphylococcus species. Biofilm production of 166 staphylococci was phenotypically investigated on Congo Red Agar (CRA); the presence of icaA, icaD and IS256 genes were investigated by polymerase chain reaction (PCR). 74 of the isolates (44.6%) were identified as methicillin resistant Staphylococcus aureus (MRSA), 25 (15.1%) as methicillin sensitive S.aureus (MSSA), 25 (37.3%) as Staphylococcus hominis, 20 (12%) as S.epidermidis, ten (15%) as Staphylococcus haemolyticus, nine (13.4%) as Staphylococcus capitis, two (3%) Staphylococcus saprophyticus and one (1.5%) as Staphylococcus warnerii. Of the MRSA strains, 52 were isolated from blood and 22 from nose; all MSSA strains were isolated from nose cultures. Coagulase-negative staphylococci (CoNS) strains were composed of invasive and non-invasive strains isolated from nose, catheter tip and blood cultures from patients with catheter. Production with CRA method was found to be statistically significant in invasive isolates (p< 0.001). It is concluded that; as the biofilm formation capacity of invasive isolates can cause refractory infections and the importance of carriage and hospital infections of these bacteria, it is important to prevent the spread of these isolates. A combination of phenotypic and genotypic tests is recommended for the investigation of biofilm formation in staphylococci. 40.3% of the CoNS isolates, and 85.8% of S.aureus isolates produced biofilm on CRA (p< 0.001) and with PCR method the ratio of carrying three genes was found to be statistically important in S.aureus when compared with CoNS. Carriage of three genes and biofilm formation capacity of invasive isolates can cause refractory infections and the importance of carriage and hospital infections of these bacteria, it is important to prevent the spread of these isolates. A combination of phenotypic and genotypic tests is recommended for the investigation of biofilm formation in staphylococci.

[In vitro effect of vancomycin and daptomycin on biofilm formation of coagulase-negative staphylococci strains]

Coagulase-negative staphylococci (CNS) are one of the primer agents of blood stream infections (BSI) and catheter-related bloodstream infections (CR-BSI) which are associated mostly with the usage of central venous catheters and, important causes of morbidity and mortality despite the usage of antibacterial and supportive treatment. It is important to determine the properties of these causative microorganisms in order to make appropriate treatment of such infections. The aims of our study were to evaluate the biofilm formation of coagulase negative staphylococci (CNS) which were causative agents of bloodstream (BSI) and catheter related bloodstream infections (CR-BSI), to determine the minimum inhibitory concentration (MIC) of planktonic forms and minimal biofilm eradication concentration (MBEC) of sessile forms for vancomycin and daptomycin and to evaluate the efficacy of these antibiotics in infections with biofilm-forming isolates in vitro. A total of 65 CoNS (n= 26 catheter colonizers, n= 28 CR-BSI, n= 11 BSI agents) were identified by conventional methods and also with BD Phoenix (Becton Dickinson, USA) and Bruker Microflex MS (Bruker Daltonics, Germany) systems. Methicillin resistance was determined by the presence of mecA gene with PCR. MIC values of vancomycin and daptomycin were investigated by broth microdilution, for daptomycin medium containing 25 and 50 μg/ml Ca++ were used. Assessment of biofilm formation and detection of MBEC were determined by microplate method. The clonal relationship was investigated by the PFGE method. A total of 65 isolates; 26 catheter colonizers, 28 CR-BSI agents and 11 BSI agents were evaluated and identified as Staphylococcus epidermidis (n= 33), Staphylococcus haemolyticus (n= 16), Staphylococcus hominis (n= 15), and Staphylococcus capitis (n= 1). 81.5% of the isolates were found to be methicillin resistant and all of them were found to be sensitive to vancomycin (MIC= 0.125-4 μg/ml) and daptomycin (MIC= 0.062-0.25 μg/ml in 25 μg/ml Ca++ and MIC= 0.031-0.50 μg/ml in 50 μg/ml Ca++ containing medium). MIC values were lower in medium containing 50 μg/ml Ca++ for daptomycin. As it is known that the efficacy of daptomycin depends on the physiological levels of Ca++, which causes conformational changes in the structure of these antibacterials. Our findings also suggested that high levels of Ca++ are needed to ensure the efficacy of daptomycin. All of the isolates produced biofilm at different strengths of positivity (n= 12/18.5% weak, n= 35/%53.8 moderate, n= 18/%27.7 strong). MBEC and MBEC/MIC values for vancomycin were found to be higher than daptomycin (p< 0.001). Strong biofilm producers had higher MBEC and MBEC/MIC, MBEC50/MIC50 ve MBEC90/MIC90 values (p< 0.05). Especially in infections with biofilm forming isolates, the detection of only MIC values are not always sufficient in the treatment of biofilm-related infections as they reflect the sensitivity of planktonic bacteria. The inconsistency between the MIC and MBEC values and the high rates of MBEC/MIC found in our study supported this prediction.The lower detection of MBEC and MBEC/MIC values of daptomycin compared to the same values of vancomycin suggested that daptomycin might be effective at lower doses than vancomycin in the treatment of biofilm infections.

Wound and soft tissue infections of Serratia marcescens in patients receiving wound care: A health care-associated outbreak

We described a health care-associated Serratia marcescens outbreak of wound and soft tissue infection lasting approximately 11 months at Ankara University Ibni Sina Hospital. After identification of S marcescens strains from the clinical and environmental samples, and their susceptibility testing to antimicrobial agents, pulsed-field gel electrophoresis (PFGE) was performed to detect molecular epidemiologic relationships among these isolates. The strains which were isolated from the saline bottles used for wound cleansing in the wound care unit were found to be 100% interrelated by PFGE to the strains from the samples of the outbreak patients. Reuse of the emptied bottles has no longer been allowed since the outbreak occurred. Besides, more efficient and frequent infection control training for hospital staff has been conducted.

[Molecular characterization of Salmonella enterica serovar Typhimurium strains isolated from humans in Turkey]

Multidrug resistant (MDR) Salmonella infections, especially infections due to Salmonella Typhimurium DT104 phage type strains are an important public health issue in many parts of the world. S.Typhimurium is the most common serotype isolated from clinical samples in Turkey but we have limited data about the phage types of these isolates. The aims of this study were to find out whether these MDR S.Typhimurium isolates are DT104 phage type isolates and have class 1 integrons and to investigate the relationships of these characteristics between plasmid and pulsed field gel electrophoresis (PFGE) profiles. A total of 66 S.Typhimurium stock strains selected from Enterobacteria Laboratory culture collections of Ankara University School of Medicine, Department of Medical Microbiology were investigated by plasmid profile analysis (PPA) and PFGE with the use of XbaI and SpeI enzymes. The presence of class 1 integrons and the phage type 104 were investigated by polymerase chain reaction (PCR). The strains used in the study were sporadically isolated cases from seven provinces after year 2000 with ACSSuT (63), ACGSSuTT/S (1), ACSSuTT/S (1) and ASSuTT/S (1) resistance types [ampicillin (A), chloramphenicol (C), gentamicin (G), streptomycin (S), sulphonamide (Su), tetracycline (T), trimethoprim/sulfamethoxazole (T/S)]. Of the isolates 65 were found as DT104 phage type. Forty-three S.Typhimurium DT104 isolates that carry class 1 integrons had five different bands between 350-1600 base pairs (bp); all of the isolates harbored 1-4 plasmids with sizes ranging from 1.0-180 kbp and 62 isolates had 90 kbp plasmid which was serotype specific and virulence related. S.Typhimurium DT104 isolates were grouped into five (X1-X5) and seven (S1-S7) profiles with XbaI and SpeI enzymes, respectively. When the profiles of the two enzymes were evaluated, 58 of the 65 (89.2%) isolates showed similar (X1.S1) profile. The molecular characteristics of the most S.Typhimurium isolates were clustered in similar groups when class 1 integron, plasmid and PFGE types were analyzed together. In this study we showed that nearly all S.Typhimurium isolates with five drug resistance pattern (ACSSuT) were DT104 isolates. PFGE profiles of these sporadic isolates suggested that they were epidemiologically related.

Molecular Characterization of Methicillin-Resistant Staphylococcus aureus Bloodstream Isolates in a Turkish University Hospital Between 2002 and 2012

AIMS

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important pathogens in the hospital environment. Monitoring of this pathogen by molecular characterization and phenotypic methods is important for the development of suitable infection control measures and proper therapy design. In this study, our aim was to investigate the molecular epidemiological characteristics of MRSA bloodstream isolates obtained from patients hospitalized at Ankara University Ibn-i Sina Hospital in a 10-year period (2002-2012) and monitor the possible changes. A total of 134 isolates were characterized according to their antimicrobial susceptibility profiles, biofilm formation capabilities, accessory gene regulator (agr) locus types, presence of genes encoding Panton-Valentine leukocidin (PVL), staphylococcal enterotoxins A-J (SEs A-J), toxic shock syndrome toxin, sasX, and genes associated with biofilm formation (icaD, icaA, IS256) by polymerase chain reaction. The staphylococcal cassette chromosome mec (SCCmec) types of isolates were also defined and their clonal relationships were investigated by pulsed-field gel electrophoresis (PFGE) analysis and multilocus sequence typing was performed for representative isolates obtained by PFGE.

RESULTS

The majority of the isolates were resistant to rifampin (100%), ciprofloxacin (97%), tetracycline (97.7%), and gentamicin (94.7%); 100% carried type-III SCCmec and 89.5% were agr type-1. All the isolates were negative for PVL, and sasX genes while all of them carried the icaD, icaA, and IS256 genes. The most common SE was enterotoxin A (97%). Four major PFGE patterns with the dominance of one pattern and seven unique patterns were obtained. All the representative PFGE isolates (n = 11) belonged to sequence type 239.

CONCLUSION

We have documented the characteristics of the dominant MRSA clone in our hospital, which was a PVL (-), sasX (-) ST239 clone carrying sea (+) with type-III SCCmec, and type-1 agr locus.

Determination of in vitro activities of polymyxin B and rifampin in combination with ampicillin/sulbactam or cefoperazone/sulbactam against multidrug-resistant Acinetobacter baumannii by the E-test and checkerboard methods

The aim of this study was to investigate the in vitro activities of polymyxin B (PB) and rifampin (RIF) in combination with ampicillin/sulbactam (AS) or cefoperazone/sulbactam (CS) against 20 multidrug-resistant Acinetobacter baumannii (MDR-AB) isolates by the checkerboard and E-test methods. Fractional inhibitory concentration index (FICI) values were defined as synergy, FICI ≤ 0.5; additivity, 0.5 < FICI ≤ 1.0, indifference, 1.0 < FICI < 4.0; and antagonism, FICI ≥ 4. Synergistic interaction was detected only for the RIF + AS and RIF + CS combinations. While the most frequently detected interaction type for PB + AS or PB + CS combinations was indifference, some showed antagonistic interactions. The detection rate of synergy was significantly higher by the checkerboard than by the E-test method, and the detection rate of indifference was significantly higher by the E-test than by the checkerboard method for RIF + AS combination (P ≤ 0.0001). In addition, no statistically significant difference was detected between the checkerboard and E-test methods for the detection rates of interaction types for any of the other combinations (P > 0.05), except for PB + CS combination for the detection of additivity (P = 0.018). Owing to the high percentage of synergistic interactions between RIF and AS, we considered this combination as an effective therapeutic option for MDR-AB infections.

[Molecular characterization of beta-lactamase-associated resistance in Acinetobacter baumannii strains isolated from clinical samples]

Acinetobacter baumannii is an important cause of nosocomial infections that particularly increase the mortality and the morbidity at the intensive care units of the hospitals. The aims of this study were to evaluate the resistance genes, antibiotic susceptibility and the clonal relations among Acinetobacter strains isolated from clinical samples and to determine the resistance mechanisms related to these bacteria in our hospital. A total of 201 A.baumannii strains isolated from different clinical samples (35.3% from tracheal aspirate, 27.3% from blood, 18.4% from abscess material, 19% from other samples) of 160 inpatients evaluated at the Ibni Sina Hospital Central Bacteriology Laboratory, Ankara University School of Medicine, Turkey from April 2010 to December 2011, were included in the study. Identification of the isolates and their susceptibility testing against amikacin, ciprofloxacin, tetracycline, sulbactam/ampicillin, trimethoprim/sulfametoxazole (SXT), ceftazidime, gentamicin, imipenem, levofloxacin, meropenem, piperacillin/tazobactam, cefoperazone/sulbactam, cefepime and colistin were performed by the automated systems, namely Vitek 2 (bioMérieux, France) and BD Phoenix (Becton Dickinson, USA). The molecular mechanisms of beta-lactamase resistance and the presence of integrons were analyzed by polymerase chain reaction (PCR). Moreover, since blaPER-1 gene is of high frequency in Turkey, it was also investigated in the isolates. Pulsed-field gel electrophoresis (PFGE) was performed to examine the clonal relations between isolates. Our results indicated that multidrug resistance rate of A.baumannii was 94.5% (190/201), while 94% (189/201) of the isolates were susceptible to colistin thus making it the most potent antimicrobial agent, followed by amikacin and SXT with a susceptibility rate of 32%. Twelve colistin-resistant isolates were further investigated with the E-test method (AB Biodisk, Sweden) and found to be colistin-resistant. While the results were negative for the genes responsible from metallo-beta-lactamase production, positive results were obtained for blaOXA genes at various rates (OXA-51 100%; OXA-23 91.5%; OXA-58 7%; OXA-24 2%). PFGE results revealed four different main clones (29 isolates in genotype A, 23 in genotype B, 18 in genotype C and 7 in genotype D) in the study population. No common epidemic isolate was detected. Class 1 integrons which take part in the transfer of resistance genes were detected in 112 (55.7%) isolates. There was no statistically significant difference between the genotype distributions of class 1 integron positive strains (p> 0.05). The relationship between the presence of integron in multidrug resistant isolates and resistance to tetracyclin, SXT, imipenem, meropenem, cefoperazone/sulbactam and cefepime were found to be statistically significant (p< 0.05). Of the isolates 42 (21%) were positive for blaPER- 1 gene and all were resistant to ceftazidime. This study indicated that blaOXA genes found together with blaOXA-51 genes play an important role in carbapenem resistance of A.baumannii strains. Moreover, multidrug resistance is still an important problem in infections caused by A.baumannii and integrons play a role in the transfer of the resistance genes. In conclusion, multidrug resistant A.baumannii strains were common in our hospital and our epidemiologic data would be helpful for further investigations and in therapeutical approaches.

Identification of methicillin-resistant Staphylococcus aureus carrying an exfoliative toxin A gene encoding phage isolated from a hospitalized patient in Turkey

From the four known isoforms of the staphylococcal exfoliative toxins (ETs), only ETA and ETB are the major causative agents. General knowledge is that the gene for ETA is located on the chromosome, whereas that for ETB is located on a large plasmid. Yoshizawa and co-workers (2000, Microbiol. Immunol. 44(3): 189–191) isolated, for the first time, a temperate phage (φETA) that carried the structural gene for ETA from an ETA-producing strain of Staphylococcus aureus. In this study, we presented eta gene encoding temperate phages isolated from methicillin-resistant S.aureus (MRSA) isolates obtained from patients in a Turkish hospital. Molecular analysis of the phage genome revealed that the eta gene is located upstream to amidase and holin genes, the same as in the φETA genome. However, partial sequence analysis of amidase and holin genes revealed polymorphic variation. In addition to polymorphic variation, restriction fragment length polymorphism (RFLP) analysis of all of the phage genomes showed that the ETA-containing phage is different from the rest of the phage genomes. The phylogenetic dendrogram of pulsed field gel electrophoresis (PFGE) analysis showed that the ETA-carrying MRSA is quite different from the rest of the MRSA strains. This is the first report showing that a MRSA strain carries an ETA-encoding phage.

[25S intron analysis followed by restriction enzyme digestion performed for genotyping Candida albicans isolates]

Candida albicans is the most frequently encountered fungal pathogen especially in the immunocompromised hosts. Genotyping clinical microbial isolates is important for obtaining epidemiological data and for establishing appropriate infection control strategies in the hospital setting. 25S intron analysis is an easy and reliable method used for genotyping C.albicans strains. As it has a low discriminatory power, its use is limited in epidemiological studies. In this study, our aim was to genotype clinical C.albicans isolates by using 25S intron analysis followed by restriction enzyme digestion in order to develop a more discriminative genotyping system for C.albicans. A total of 260 clinical C.albicans strains isolated from various infection sites (121 blood, 69 sputum, 36 vaginal discharge, 26 wound, 8 urine samples) were genotyped by 25S intron analysis, and all the products obtained by polymerase chain reaction (PCR) were digested with HaeIII restriction enzyme. Discriminatory power of each method was calculated. Among the isolates 184 (70.8%) were classified as genotype A, 42 (16.2%) as genotype B, and 34 (13%) as genotype C by 25S intron analysis. Discriminatory power of the method was calculated as 0.46. HaeIII restriction of genotype A, B and C isolates produced ten, one, and five restriction patterns (genotypes), respectively. By the addition of restriction enzyme analysis, the number of genotypes obtained was increased to 16, and the discriminatory power of the method to 0.79. Combining different genotyping methods increases the discriminatory power by increasing the number of genotypes obtained. However, there is also a risk to split certain strains in different genotypes by the different methods used and this makes the genotypic evaluation more difficult. On the other hand, combining 25S intron analysis with restriction enzyme analysis increases the discriminatory power without introducing a totally different method, and makes the method more suitable for epidemiological purposes and for genotyping clinical isolates. Different enzymes instead of HaeIII should be tested to evaluate the effect on the discriminatory power. In order to evaluate the relationship between the genotypes obtained by this method and parameters such as patient characteristics, clinical data, and antifungal susceptibilities, more sophisticated studies can be performed.

[Investigation of Salmonella serotype Enteritidis isolates by plasmid profile analysis and pulsed field gel electrophoresis]

In this study a total of 122 Salmonella serotype Enteritidis stock strains selected from the culture collection of Enterobacteriaceae Laboratory of Ankara University Faculty of Medicine, Department of Medical Microbiology, were investigated by plasmid profile analysis with the method defined by Kado and Liu and pulsed field gel electrophoresis (PFGE) according to World Health Organization protocols using SpeI and XbaI macrorestriction enzymes, for better understanding of the molecular epidemiology of S. Enteritidis. The study strains were selected from a collection of previously isolated epidemic (n= 13) and sporadic (n= 109) strains (103 stool, 16 blood and one each bile, urine and cerebrospinal fluid) obtained from 10 different cities after the year 2000. PFGE patterns were analyzed with Gene Directory software (Syngene, UK) and a similarity index was determined by using Dice coefficient and the unweighted pair group method with mathematical averaging (UPGMA). Plasmid-carrying 110 (90%) strains that harbored 1-4 plasmids with sizes ranging from 2.0 to 100 kb were separated into patterns more than 14 (p1-p14). A total of 85 (69.7%) isolates harbored the 57 kb plasmid solely or in combination with other plasmids. By PFGE, 11 distinct patterns were shown with each enzyme SpeI and XbaI. S. Enteritidis strains after digestion with macrorestriction enzyme SpeI generated 11 different PFGE patterns (A to K), whereas XbaI generated also 11 different PFGE patterns (a to k). PFGE pattern A consisted of 93 strains (76.2%) after digestion with macrorestriction enzyme SpeI, while PFGE pattern a consisted 53 (43.4%) and PFGE pattern b 42 strains (34.4%) after digestion with macrorestriction enzyme XbaI. Using two macrorestriction enzymes two PFGE cluster profiles Aa (50 strains, 40.9%) and Ab (42 strains, 34.4%) were found to be predominating among 17 different PFGE clusters. Our results confirmed the clonal nature of S. Enteritidis strains in Turkey. The use of two enzymes in PFGE analysis appeared to increase the discriminatory power of PFGE, leading to greater diversity among strains. PFGE analysis performed by SpeI and XbaI enzymes combined with plasmid profiling could be established as a useful tool for detection of genetic relationship between isolates.

[Investigation of presence of class 1 integrons in clinical isolates of carbapenem-resistant Acinetobacter baumannii]

Acinetobacter species, particularly Acinetobacter baumannii, are important opportunistic pathogens responsible for nosocomial infections. They are often resistant to a wide range of antibiotics, including broad-spectrum beta-lactams, aminoglycosides and quinolones. This study was aimed to investigate the presence of class 1 integrons in nosocomial A.baumannii isolates. Eighty-nine carbapenem resistant nosocomial A.baumannii strains recovered from various clinical samples at Ankara Numune Teaching and Research Hospital during September 2006-August 2007, were included in the study. To determine the presence of integrons in Acinetobacter isolates, a chromosomal DNA region that consists of internal variable gene sequences restricted to two conserved regions, was amplified by using 5'CS and 3'CS primers. Class 1 integrons were demonstrated in 93.3% (83/89) of the strains. The range of inserted gene cassette sizes detected varied from 100 to 3000 base pairs. Recent studies have shown that the majority of integrons belong to class 1 among Acinetobacter species. This study also indicated that class I integrons were present in 93.3% of the A.baumannii isolates. The isolates were genotyped by pulsed-field gel electrophoresis (PFGE) and found to be distributed into 13 different groups, two of the groups predominated the isolates (group A: 29, group C: 21 isolates). Five of 6 isolates that did not have the class 1 integron (6/89; 6.7%) exhibited the same PFGE pattern (group C). Since integrons are important for the dissemination of antibiotic-resistance genes among nosocomial Acinetobacter species, the investigation of integrons by polymerase chain reaction method seems to be a rapid and simple technique for revealing the epidemic potential of A.baumannii isolates.

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.

[Molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae strains isolated between 2004-2007 in Ankara University Hospital, Turkey]

The prevalence of carbapenem-resistant gram-negative bacteria in the hospital setting is in an increasing trend worldwide. Since most of the carbapenem-resistant Enterobacteriaceae are resistant to all antimicrobial agents except polymyxins and tigecycline, the emergence of carbapenem resistance in Klebsiella pneumoniae strains requires careful monitoring. This study was conducted to analyse the epidemiological relatedness between the carbapenem-resistant isolates of K. pneumoniae collected from different wards (intensive-care, surgery, hematology, neurology, internal medicine, emergency services) of Ankara University Hospital. A total of 26 carbapenem-resistant K. pneumoniae isolates (13 blood, 6 urine, 2 bronchoalveolar lavage, 1 abscess, 1 tissue, 1 catheter tip, 1 drainage fluid, 1 tracheal lavage fluid) were identified and antibiotic susceptibility tests were performed with API 20E System or VITEK 2 Compact (Bio-Merieux, France) at the Central Laboratories of Ankara University Hospital between February 2004 and April 2007. MICs of imipenem and meropenem were also confirmed using E-test (AB Biodisk, Sweden). The clonal relationship between the isolates was studied by pulsed-field gel electrophoresis (PFGE). After digestion of total genomic DNA with restriction endonuclease Xbal, the 26 isolates generated 7 PFGE profiles. PFGE pattern B consisting of different antibiotic susceptibility profile was seen only in 2006. Carbapenem-sensitive strains isolated at the same time from the same wards which carbapenem-resistant isolates were recovered, generated different PFGE patterns. The predominant carbapenem-resistant isolates in our hospital were found clonally related. Interhospital transmission of carbapenem-resistant K. pneumoniae strains which have a particular epidemic potential, is likely to occur during patient transfer between wards. It is likely that intensive efforts, similar to those used to control vancomycin resistant enterococci, are needed to identify and control the spread of resistant Klebsiella species. Therefore, active surveillance and strict infection control measures for this multidrug-resistant microorganism should be implemented at local and national basis.

[Influence of reaction optimization on the results of PCR amplification of Panton-Valentine leukocidin genes among Staphylococcus aureus isolates]

Panton-Valentine leukocidin (PVL) is an important virulence determinant of Staphylococcus aureus. Polymerase chain reaction (PCR) amplification of the genes encoding PVL is the most widely used method for determining PVL-positivity. In this study, we used two different primer sets and different annealing temperatures for each set to investigate the effect of optimization of PCR parameters on the amplification results. A total of 321 S. aureus clinical isolates (84.4% methicillin-resistant S. aureus, 76.9% nosocomial) were included to the study. Two different primer sets and two different annealing temperatures were applied for the amplification of PVL gene. For this purpose while luk-PV-1 and luk-PV-2 primers and 55 degrees C and 58 degrees C annealing temperatures were used to amplify the 433 bp region inhabiting the luk-S PV and luk-F PV genes, PVLup and PVLdn primers and 50 degrees C and 48 degrees C annealing temperatures were used to amplify the 1918 bp region inhabiting the same genes. luk-PV-1 and luk-PV-2 primers yielded amplicons at 55 degrees C in 50.2% (161/321) and at 58 degrees C in 1.6% (5/321) of the isolates. To discriminate the positive amplicons from the crossly amplified PCR products, restriction endonuclease analysis was performed and it was observed that the five amplicons generated by luk-PV-1 and luk-PV-2 primers at 58 degrees C were cut by BspH1 enzyme as expected for the positive amplicons. None of the isolates yielded amplicons by PVLup and PVLdn primers at 50 degrees C, however, only 1.6% of the isolates yielded amplicons at 48 degrees C. These isolates were the same with the ones that were PVL positive with luk-PV-1 and luk-PV-2 primers at 58 degrees C. These data revealed that only 1.6% of the study isolates were PVL positive. These results showed that inappropriate cycling conditions may lead to false-negative or false-positive results in PVL-gene amplification. Restriction endonuclease or sequence analysis may be used to differentiate crossly-amplified sequences from PVL-positive amplicons. We suggest using different primers and different annealing temperatures in PVL gene amplification before concluding on the study results. Using positive and negative control strains in each run and optimization of the study protocol not only according to the literature data but also due view to the laboratory experience seems critical for obtaining reliable data.

Molecular investigation of salmonella choleraesuis and salmonella hadar strains isolated from humans in Turkey

Eleven Salmonella Choleraesuis and seven Salmonella Hadar strains isolated from various clinical humand samples were investigated by plasmid profile analysis, enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and pulsed-field gel electrophoresis (PFGE) in order to obtain information at a molecular level on the epidemiology of S. Choleraesuis and S. Hadar, which are significantly present in Turkey. Plasmid profile analysis showed that 10 (90.9%) of 11 S. Choleraesuis isolates harbored one to two plasmids with sizes of 2.0, 5.0 or 6.5 kb; and 5 (71.4%) of 7 S. Hadar isolates harbored one to three plasmids ranging from 2.5 to 70 kb. ERIC-PCR was performed using ERIC-2 primers; since isolates within each serotype showed similar band models, we concluded that ERIC-PCR is not suitable for differentiating isolates within the same serotype and for grouping into clusters. In PFGE using the AvrII enzyme, S. Choleraesuis isolates formed three clusters, and S. Hadar isolates formed three clusters; using the XbaI enzyme, S. Choleraesuis isolates formed two clusters, and S. Hadar isolates formed four clusters. These results showed that plasmid profile analysis and PFGE are reliable and discriminative methods that would complement antibiograms, and could contribute to the investigation of outbreak epidemiology. This is the first report on S. Choleraesuis and S. Hadar isolates from Turkey investigated by plasmid profile analysis, ERIC-PCR and PFGE methods.

[Molecular characteristics of methicillin-resistant Staphylococcus aureus strains isolated from blood cultures between 2002-2005 in Ankara University Hospital]

This study was conducted to investigate the antimicrobial susceptibility, Panton Valentine leucocidine (PVL) and toxin (enterotoxin A-J, staphylococcal toxic shock toxin) genes, agr types, staphylococcal cassette chromosome mec (SCCmec) types and pulsed field gel electrophoresis (PFGE) profiles of a total of 100 non-duplicate methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates collected between 2002-2005 at Ankara University Ibn-i Sina Hospital. Antimicrobial susceptibilities were investigated by a semi-automated system (miniAPI, BioMerieux, France); PVL, mecA and toxin (sea, seb, sec, sed, see, seg, seh, sei, sej, tst) genes by polymerase chain reaction (PCR) and SCCmec and agr typing were performed by multiplex PCR. While all isolates were susceptible to vancomycine, aminoglycoside and tetracycline resistance was determined in 91%, ciprofloxacine in 93%, rifampin in 92%, erythromycine in 79% and trimethoprim-sulphametoxazole in 8% of the isolates. mecA gene was detected in all of the isolates, however, PVL positive isolate was not detected. sea was the most frequently (77%) detected enterotoxin gene. SCCmec typing revealed type III in 84 (84%) and agr typing revealed type I in 91 (91%) of the isolates. Multilocus Sequence Typing (MLST) of five representative isolates (two isolates with pattern A, one isolate each from patterns B, C and D) revealed sequence type (ST) 239. This study documented that the dominant MRSA clone in our hospital had SCCmec type III, agr type 1, PVL negative, sea positive and of ST 239. Larger scale intercity and nation wide studies are needed to find out the clonal characteristics of hospital acquired MRSA in Turkey.

[Comparison of different primers used for the genotyping of Candida albicans clinical isolates by randomly amplified polymorphic DNA method]

Candida albicans causes severe infections with high mortality rates especially in immunocompromised patients. The aim of this study was to evaluate the efficiency of randomly amplified polymorphic DNA (RAPD) method and compare the discriminatory powers (DP) of different primers used for genotyping Candida albicans isolates. A total of 109 C. albicans strains recovered from throat, sputum, blood, feces, urine, vagina and wound cultures of 65 hospitalized paediatric patients with haematologic malignancy were evaluated by RAPD method using 10 different primers (OPE-03, OPE-04, OPE-12, OPE-18, OPE-19, OPE-20, OPF-10, OPF-12, P1 and P2) between June 1999-April 2003. Strains were separated into groups by analyzing band patterns derived from each primer and the DP was calculated. Reproducibility of the method was determined by evaluating randomly chosen 20 isolates with the same and different PCR devices under the same PCR conditions. C. albicans isolates generated 1-16 bands and were grouped in 41-80 genotypes depending on the primers used. DP of the RAPD method was calculated as > or = 0.90 for each primer (range between 0.90-0.99), which were accepted as reliable values. However, the strains clustered in the same group when studied with a primer could be dispersed into different groups by another primer. The reproducibility of the method was poor and the comparison of band patterns was difficult especially in isolates which generated many bands. In conclusion, for obtaining reliable results by RAPD method, using more than one primer and comparative analysis of these primers are appropriate. RAPD is an adequate method for studying small outbreaks in which a few number of isolates are evaluated, but it is laborious and unreliable for many number of isolates recovered in a long time period because of its poor reproducibility and difficulties in evaluating the strains generating many bands.

Bevacizumab sterility in multiple doses from a single-use vial

BACKGROUND

Recent reports have demonstrated that refrigerated bevacizumab can be stored for up to 3 weeks at 4 degrees C without loss of efficacy. There have been no previous reports addressing bevacizumab's sterility when stored and used as multiple doses from a single-use vial.

OBJECTIVE

To evaluate the sterility of bevacizumab when used as multiple doses from a single-use vial.

METHODS

Four groups of vials were used to simulate the storage and use conditions for bevacizumab. Each group contained 11 doses of 0.2 mL of bevacizumab. One sample from each group was cultured once each day at 37 degrees C for 10 days; one sample from each group was left for 15 days. MacConkey agar, blood agar, thioglycollate broth, and Sabouraud medium were used to assess bacterial and fungal growth.

RESULTS

A total of 44 samples of bevacizumab were included in this study. Each sample was placed on 4 growth media for microbial readings. All samples were found to be negative for microbial growth. No significant differences were observed among the groups. Possible limitations of this study included the number of samples for each group and in vitro design of the study, which might have affected the growth of bacterial organisms.

CONCLUSIONS

Storage and multiple use of bevacizumab from single-use vials does not seem to result in microbial contamination.

Urease activity and urea gene sequencing of coccoid forms of H. pylori induced by different factors

Helicobacter pylori exists in two morphologic forms: spiral shaped and coccoid. The nonculturable coccoid forms were believed to be the morphologic manifestations of cell death for a long time. However, recent studies indicate the viability of such forms. This form of H. pylori is now suspected to play a role in the transmission of the bacteria and is partly responsible for relapse of infection after antimicrobial treatment. Urease activity of H. pylori is an important maintenance factor. Determination of urease activity and possible mutations in the DNA sequences of coccoid bacteria will hence contribute to the understanding of pathogenesis of infections, which these forms might be responsible for. In this study, our aim was to analyze the urease activity and investigate the urease gene sequences of coccoid H. pylori forms induced by different factors with respect to the spiral form. For this purpose, the urease activities of H. pylori NCTC 11637 standard strain and two clinical isolates were examined before and after transformation of the cells to coccoid forms by different methods such as exposure to amoxicillin, aerobiosis, cold starvation, and aging. The effects of these conditions on the urease gene were examined by the amplification of 411-bp ureA gene and 115-bp ureB gene regions by PCR technique and sequencing of the ureA gene. The urease activities of coccoid cells were found to be lower than those of the spiral form. ureA and ureB gene regions were amplified in all coccoid cells by PCR. Inducing the change to coccoid form by different methods was found to have no effect on the nucleotide sequence of the ureA gene. These results show that the urease gene region of coccoid H. pylori is highly protected under various mild environmental conditions.

[Mupirocin resistance in methicillin-resistant Staphylococcus aureus strains isolated from wound infections]

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important pathogen in community-acquired and nosocomial infections. The unique bactericidal action of mupirocin makes it one of the few antibiotics still effective against MRSA. The purpose of this study was to investigate the mupirocin resistance in MRSA strains isolated from wound infections of in- and out-patients of two distinct hospitals located in Ankara and Istanbul. A total of 143 MRSA strains were included in the study. Mupirocin resistance was investigated by Kirby-Bauer disk diffusion method and the results were confirmed by determination of the MIC values by E-test strips. Among 143 MRSA isolates, mupirocin resistance was detected by none of the methods, and overall mupirocin sensitivity was detected as 100 percent. The majority of mupirocin resistant MRSA is isolated from wound infections. The aetiology mostly depends on the increased topical use of the agent. The method used in the detection of mupirocin resistance and interpretation of the results are important parameters in the determination of mupirocin resistance in MRSA strains. Since there was no resistant strain among 143 clinical isolates obtained from two different hospitals, it was concluded that, mupirocin resistance is not an important problem in these regions currently, and mupirocin may be safely used in treating wound infections.

Plasmid profiles and randomly amplified polymorphic DNA analysis of Salmonella enterica serotype Enteritidis strains from outbreaks and sporadic cases in Turkey

The aim of the study was to investigate the characteristics of Salmonella serotype Enteritidis strains isolated from outbreaks and sporadic cases in Turkey by plasmid profiles and randomly amplified polymorphic DNA (RAPD) patterns. A total of 64 S. Enteritidis clinical strains were selected from the culture collection of the Enterobacteria Laboratory of Ankara University Medical School Department of Microbiology and Clinical Microbiology for molecular analysis using the plasmid profiles and RAPD method. Fifty-six isolates (88%) harbored one to four plasmids ranging in size from 2.5 to 100 kbp. 57 kbp plasmids were the most common plasmids, and forty-four strains (69%) carried 57 kbp plasmids alone or together with other plasmids. The outbreak strains carried the same plasmid profile: three plasmids sized 57, 40, 3.0 kbp. None of the strains analyzed displayed any RAPD bands with the primer OPB-17. By using primer p-1254, 42 strains (66%) were divided into fourteen RAPD patterns. Ten of the outbreak strains (77%) showed >80% similarity by cluster analysis program. Analysis of RAPD-PCR with primer p-1254 proved an easy, rapid and discriminative method complementing antibiogram and plasmid profiles in routine laboratories, and may contribute to the investigations of S. Enteritidis which still cause outbreaks in Turkey. This study presents the first report on S. Enteritidis isolates in Turkey investigated by plasmid profiles and RAPD methods.

Comparison of hybrid capture and reverse transcriptase polymerase chain reaction methods in terms of diagnosing human cytomegalovirus infection in patients following hematopoietic stem cell transplantation

OBJECTIVE

Human cytomegalovirus (CMV) is a life threatening cause of infection among hematopoietic stem cell recipients. Developing reliable methods in detecting the CMV infection is important to identify the patients at risk of CMV infection and disease. The aim of this study was to compare the 2 tests- hybrid capture test, which is routinely used in the diagnosis of CMV infection among hematopoietic stem cell recipients, and reverse transcriptase polymerase chain reaction (RT-PCR) detecting UL21.5 mRNA transcripts of the active virus.

METHODS

In this prospective study, a total of 178 blood samples obtained from 35 patients following allogeneic hematopoietic stem cell transplantation at the Bone Marrow Transplantation Unit of the Hematology Department, Ibn-i Sina Hospital of Ankara University School of Medicine, Turkey between January 2003 and September 2003 were analyzed. Hybrid capture and RT-PCR using UL21.5 gene transcript method to investigate HCMV in blood samples were performed at the Department of Microbiology and Clinic Microbiology Ankara University School of Medicine, Turkey.

RESULTS

When hybrid capture test was accepted as the golden standard, the sensitivity of RT-PCR was 33%, specificity 100%, false negativity 67%, false positivity 0%, positive predictive value 100%, negative predictive value 74%, and accuracy was 77%.

CONCLUSION

Improving this test by quantification, and application of additional gene transcripts, primarily the late gene transcripts can help increase the sensitivity and feasibility.

Initial Candida dubliniensis isolate in Candida spp. positive haemocultures in Turkey between 2001 and 2004

Candida dubliniensis which was first recognized in 1995 can be easily misidentified because of its phenotypic similarities with Candida albicans. In this study blood samples of patients from various departments of Ankara University Medical Faculty between January 2001-June 2004 were investigated for the distribution of Candida spp. and the presence of C. dubliniensis. Culture positive 67 fungi were included to the study. Phenotypic tests such as chlamydospore formation, colony morphology on Staib agar, growth at 45 degrees C, carbohydrate assimilation profiles were investigated for identification and differentiation of C. dubliniensis from C. albicans. To confirm the results polymerase chain reaction were used for suspected C. albicans and C. dubliniensis isolates. Among 38 germ tube and chlamydospore forming isolates, 37 of them were found as C. albicans and one as C. dubliniensis. The incidence of C. dubliniensis in our hospital is still low, this is the first C. dubliniensis isolate as an agent of candidaemia reported from Turkey.

[Screening for Neisseria gonorrhoeae and Chlamydia trachomatis in human immunodeficiency virus positive men without urethritis symptoms]

Some of the sexually transmitted diseases' agents other than human immunodeficiency virus (HIV) take an active part in transmission of HIV infection. The objective of the study was to determine the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae in 18 HIV positive men without urethritis symptoms and in 70 HIV negative men with urethritis symptoms as control group. The urine samples were screened for C. trachomatis and N. gonorrhoeae using polymerase chain reaction (PCR). The prevalence of N. gonorrhoeae in HIV positive men without urethritis symptoms was significantly higher than that in HIV negative men with urethritis symptoms (p<0.05). HIV positive individuals should be considered as a high-risk group in respect to the other sexually transmitted diseases, thus necessitating screening for N. gonorrhoeae in order to break the infectious chain in these patients.

Detection of Candida dubliniensis in oropharyngeal samples of Turkish HIV-positive patients

The incidence of Candida dubliniensis in immunocomprimised patients in Turkey has not yet been determined. In this study the presence of C. dubliniensis in oral rinse samples of human immunodeficiency virus (HIV)-positive patients and healthy controls were investigated. Phenotypic tests like inability of growth at 45 degrees C, colony formation on Staib agar, intracellular beta-D-glucosidase activity, carbohydrate assimilation profiles and polymerase chain reaction with species-specific primers (DUBF and DUBR) were carried out for differentiation of C. dubliniensis. Of the 35 patients, four (11.4%) had C.dubliniensis in their oral cavity. Antifungal susceptibility testing of these C. dubliniensis isolates showed fluconazole MICs ranging from <0.06 to 32 microg ml(-1) and amphotericin B from <0.06 to 0.25 microg ml(-1). One isolate was dose-dependently susceptible to fluconazole (32 microg ml(-1)). This study demonstrates C. dubliniensis in HIV-positive patients from Turkey.