[Results of a multicenter study investigating plasmid mediated colistin resistance genes (mcr-1 and mcr-2) in clinical Enterobacteriaceae isolates from Turkey]. / Ülkemizde klinik Enterobacteriaceae izolatlarinda plazmit aracili kolistin direnç genlerini (mcr-1 ve mcr-2) arastiran çok merkezli çalismaya ait sonuçlar.

Colistin is a polymyxin antibiotic which is considered as one of the last line agents against infections due to multidrug resistant or carbapenem resistant gram-negative pathogens. Colistin resistance is associated with chromosomal alterations which can usually cause mutations in genes coding specific two component regulator systems. The first plasmid-mediated colistin resistance gene, mcr-1 was described in Escherichia coli and Klebsiella pneumoniae isolates in December 2015 and followed by another plasmid-mediated colistin resistance gene mcr-2 in 2016. The rapid and interspecies dissemination of plasmid-mediated resistance mechanisms through horizontal gene transfer, have made these genes considerably threatening. After the first reports, although mcr-1/mcr-2 producing Enterobacteriaceae isolates have been reported from many countries, there have been no reports from Turkey. Thus, the aim of this study was to investigate the presence of mcr-1/mcr-2 in clinical Enterobacteriaceae isolates from different parts of our country. A total of 329 Enterobacteriaceae isolates from 22 laboratories were collected which were isolated between March, 2015 and February, 2016. mcr-1/mcr-2 were investigated by polymerase chain reaction during February-March, 2016. Two hundred and seventeen of Klebsiella pneumoniae (66%), 75 of Salmonella spp. (22.8%), 31 of Esherichia coli (9.4%), 3 of Enterobacter cloacae (0.9%), 2 of Klebsiella oxytoca (0.6%) and 1 of Enterobacter aerogenes (0.3%) isolates were included to the study. Agarose gel electrophoresis results of PCR studies have shown expected band sizes for positive control isolates as 309 bp for mcr-1 and 567 bp for mcr-2. However, the presence of mcr-1/mcr-2 genes was not detected among the tested study isolates of Enterobacteriaceae. Although mcr-1/mcr-2 were not detected in our study isolates, it is highly important to understand the mechanism of resistance dissemination and determine the resistant isolates by considering that colistin is a last-line antibiotic against infections of multidrug or carbapenem resistant gram-negative bacteria. Thus, it is suggested that these mechanisms should be followed-up in both clinical and non-clinical (e.g. isolates from food animals, raw meats and environment) isolates of special populations.

Mortality predictors of Staphylococcus aureus bacteremia: a prospective multicenter study.

BACKGROUND: Staphylococcus aureus is one of the causes of both community and healthcare-associated bacteremia. The attributable mortality of S. aureus bacteremia (SAB) is still higher and predictors for mortality and clinical outcomes of this condition are need to be clarified. In this prospective observational study, we aimed to examine the predictive factors for mortality in patients with SAB in eight Turkish tertiary care hospitals. METHODS: Adult patients with signs and symptoms of bacteremia with positive blood cultures for S. aureus were included. All data for episodes of SAB including demographics, clinical and laboratory findings, antibiotics, and outcome were recorded for a 3-year (2010-2012) period. Cox proportional hazard model with forward selection was used to assess the independent effect of risk factors on mortality. A 28-day mortality was the dependent variable in the Cox regression analysis. RESULTS: A total of 255 episodes of SAB were enrolled. The median age of the patients was 59 years. Fifty-five percent of the episodes were considered as primary SAB and vascular catheter was the source of 42.1 %. Healthcare associated SAB was defined in 55.7 %. Blood cultures yielded methicillin-resistant S. aureus (MRSA) as a cause of SAB in 39.2 %. Initial empirical therapy was inappropriate in 28.2 %. Although overall mortality was observed in 52 (20.4 %), 28-day mortality rate was 15.3 %. Both the numbers of initial inappropriate empirical antibiotic treatment and the median hours to start an appropriate antibiotic between the cases of fatal outcome and survivors after fever onset were found to be similar (12/39 vs 60/216 and 6 vs 12 h, respectively; p > 0.05). High Charlson comorbidity index (CCI) score (p = 0.002), MRSA (p = 0.017), intensive care unit (ICU) admission (p < 0.001) and prior exposure to antibiotics (p = 0.002) all were significantly associated with mortality. The Cox analysis defined age [Hazard Ratio (HR) 1.03; p = 0.023], ICU admission (HR 6.9; p = 0.002), and high CCI score (HR 1.32; p = 0.002) as the independent predictive factors mortality. CONCLUSIONS: The results of this prospective study showed that age, ICU stay and high CCI score of a patient were the independent predictors of mortality and MRSA was also significantly associated with mortality in SAB.

Rotavirus and adenovirus gastroenteritis: time series analysis.

BACKGROUND: This study investigated the effects of changes in weather conditions (monthly average temperature, monthly minimum temperature, monthly average humidity) on rotavirus and adenovirus gastroenteritis frequency and whether there was a seasonal correlation. METHODS: Between 2006 and 2012, 4702 fecal samples were taken from patients ≤ 5 years of age with acute gastroenteritis; these samples were analyzed in terms of rotavirus group A and adenovirus serotype 40-41 antigens using time-series and negative binomial regression analysis. RESULTS: Rotavirus antigens were found in 797 samples (17.0%), adenovirus antigens in 113 samples (2.4%), and rotavirus and adenovirus antigens together in 16 samples (0.3%). There was a seasonal change in rotavirus gastroenteritis (P < 0.001), and a 1°C decrease in average temperature increased the ratio of rotavirus cases in those with diarrhea by 0.523%. In addition, compared with data from other years, the number of patients was lower in the first month of 2008 and in the second month of 2012, when the temperature was below -20°C (monthly minimum temperature). There was no statistically significant relationship between adenovirus infection and change in weather conditions. CONCLUSION: Various factors such as change in weather conditions, as well as the population's sensitivity and associated changes in activity, play a role in the spread of rotavirus infection.

[Resistance rates to antituberculous drugs in Sivas province]. / Sivas ilinde antitüberküloz ilaçlara direnç oranlari.

Infections caused by drug-resistant Mycobacterium tuberculosis strains represent a serious public health problem in recent years. The aim of this retrospective study was to investigate the resistance rates of M. tuberculosis complex strains isolated from clinical specimens in the laboratories of Cumhuriyet University and Numune State Hospitals in Sivas province (located in the middle Anatolia), between May 2004-May 2006 period, to the major antituberculous drugs. A total of 158 M. tuberculosis complex strains which were isolated from sputum, bronchial lavage fluid, stomach fluid, urine, pus, peritoneal fluid and cerebrospinal fluid samples, each of which from different patients were included to the study. The identification of the isolates and antituberculosis drug susceptibility testing were performed by MGIT (Mycobacteria Growth Indicator Tube) 960 system in both of the laboratories. Of 158 isolates 42 (26.6%) were found resistant to at least one of the drugs, while 116 (73.4%) were susceptible to all of the tested antimycobacterials. The overall resistance rates were found as 17.7% (28/153) for isoniazid, 11.4% (18/153) for streptomycin, 4.4% (7/153) for rifampicin, and 5.1% (8/153) for ethambutol. The rate of multidrug resistant isolates characterized with resistance to isoniazid+rifampicin were 3.8% (6/158). As a result, the most common resistance patterns observed in our region were found as single isoniazid resistance (13/158; 8.2%), single streptomycin resistance (8/158; 5.1%) and combined isoniazid+streptomycin resistance (8/158; 5.1%), respectively, with lower resistance rate to rifampicin (4.4%) in comparison to the previous results reported from Turkey.

Production, purification, and characterization of metalloprotease from Candida kefyr 41 PSB.

A thermostable metalloprotease, produced from an environmental strain of Candida kefyr 41 PSB, was purified 16 fold with a 60% yield by cold ethanol precipitation and affinity chromatography (bentonite-acrylamide-cysteine microcomposite). The purified enzyme appeared as a single protein band at 43kDa. Its optimum pH and temperature points were found to be 7.0 and 105°C, respectively. Km and Vmax values of the enzyme were determined to be 3.5mg/mL and 4.4µmolmL-1min-1, 1.65mg/mL and 6.1µmolmL-1min-1, using casein and gelatine as the substrates, respectively. The activity was inhibited by using ethylenediamine tetraacetic acid (EDTA), indicating that the enzyme was a metalloprotease. Stability of the enzyme was investigated by using thermodynamic and kinetic parameters. The thermal inactivation profile of the enzyme conformed to the first order kinetics. The half life of the enzyme at 95, 105, 115, 125 and 135°C was 1310, 610, 220, 150, and 86min, respectively.

The relationship between anticardiolipin antibodies and vascular access occlusion in patients on hemodialysis.

Vascular access occlusion is frequently seen in some patients on hemodialysis. There are different opinions about pathogenesis of recurrent access thrombosis. Anticardiolipin (aCL) antibodies have been suggested to be involved in thrombosis and can be found in a high proportion of patients with chronic renal failure. We investigated the relationship between vascular access occlusion and the level of aCL antibodies in hemodialysis patients. We measured serum IgG and IgM aCL antibodies and protein C levels in 50 patients on hemodialysis having no fistule thrombosis (group 1), in 33 patients on hemodialysis with fistule thrombosis (group 2), and 20 nondialyzed patients with chronic renal failure (group 3). There were no differences in age and duration on hemodialysis (p > 0.05). No significant correlation was found between protein C and platelet counts in all groups (p > 0.05). In group 1, aCL IgG and IgM were 2%. In group 2, aCL IgG and IgM were 6.06% and 0%, respectively. In group 3, aCL IgG and IgM were negative. We did not find any significant difference between aCL IgG and IgM in all groups (p > 0.05). No association was found between aCL antibodies and vascular access thrombosis in our patients on hemodialysis.

Applicability of Xpert MTB/RIF assay for routine diagnosis of tuberculosis: a four-year single-center experience.

BACKGROUND/AIM: The aim of this study is to assess the Xpert MTB/RIF assay for diagnosis of the Mycobacterium tuberculosis complex in clinical samples and to compare the results by reference to the diagnostic method, Bactec MGIT 960. MATERIALS AND METHODS: A total of 7407 samples were included from patients not primarily suggesting pulmonary or extrapulmonary tuberculosis (TB), collected from patients required to be screened for TB and excluding TB diagnoses since it was a differential diagnosis. Also included were a total of 411 samples from patients primarily suggesting pulmonary or extrapulmonary TB. RESULTS: In the first group, 152 of 7407 samples yielded positive results with the Bactec MGIT 960, 131 (1.77%) were found positive with Löwenstein-Jensen medium, and 295 (3.99%) were found positive with Ziehl-Neelsen staining. In the second group, 24 (5.8%), 17 (4.1%), and 28 (6.8%) of 411 samples were found positive. Xpert MTB/RIF [27 (6.6%) of 411 samples] detected 3 additional samples as positive, and these 3 cases were clinically compatible with TB. CONCLUSION: The Xpert MTB/RIF assay shows superior performance for the diagnosis of TB. Its usefulness in culture-negative patients and the best method for integrating this diagnostic method into current tuberculosis diagnostic algorithms both need further study.

Antibiotic susceptibility patterns among respiratory isolates of Gram-negative bacilli in a Turkish university hospital.

BACKGROUND: Gram-negative bacteria cause most nosocomial respiratory infections. At the University of Cumhuriyet, we examined 328 respiratory isolates of Enterobacteriaceae and Acinetobacter baumanii organisms in Sivas, Turkey over 3 years. We used disk diffusion or standardized microdilution to test the isolates against 18 antibiotics. RESULTS: We cultured organisms from sputum (54%), tracheal aspirate (25%), and bronchial lavage fluid (21%). The most common organisms were Klebsiella spp (35%), A. baumanii (27%), and Escherichia coli (15%). Imipenem was the most active agent, inhibiting 90% of Enterobacteriaceae and A. baumanii organisms. We considered approximately 12% of Klebsiella pneumoniae and 21% of E. coli isolates to be possible producers of extended-spectrum beta-lactamase. K. pneumoniae isolates of the extended-spectrum beta-lactamase phenotype were more resistant to imipenem, ciprofloxacin, and tetracycline in our study than they are in other regions of the world. CONCLUSIONS: Our results suggest that imipenem resistance in our region is growing.

Retrospective analysis of antibiotic susceptibility patterns of respiratory isolates of Pseudomonas aeruginosa in a Turkish University Hospital.

BACKGROUND: Lower respiratory tract infections due to Pseudomonas aeruginosa have a high mortality rate. Antibacterial activity of various antibiotics against P. aeruginosa isolated from each hospital depends on the variety or amount of antibiotics used in each hospital. METHOD: A total of 249 respiratory isolates of Pseudomonas aeruginosa in Sivas (Turkey) were included between January-1999 and January-2002. Isolates were tested against 14 different antibiotics by a disc diffusion method or standardized microdilution technique. RESULTS: Organisms were cultured from the following specimens: sputum (31.3%), transtracheal/endotracheal aspirates (37.8%), and bronchial lavage (30.9%). Isolates in bronchial lavage were highly susceptible to cefoperazone and aminoglycosides. Resistance to ampicillin/sulbactam was 98.8%, ticarcillin 40.1%, ticarcillin/clavulanic acid 11.2%, piperacillin 21.8%, aztreonam 66.6%, cefotaxim 75.4%, ceftriaxone 84.2%, cefoperazone 39.0%, ceftazidime 50.8%, gentamicin 57.5%, tobramycin 58.4%, amikacin 25.4%, ciprofloxacin 16.1%, and imipenem/cilastatin 21.6%. The term multidrug-resistant P. aeruginosa covered resistance to imipenem, ciprofloxacin, ceftazidime, gentamicin, and piperacillin. 1.2% of isolates were multidrug-resistant. CONCLUSIONS: These findings suggest that amikacin resistance increases progressively in Turkey. Piperacillin and ticarcillin/clavulanate were the most active agents against both imipenem- and ciprofloxacin-resistant isolates in our region.

Community-acquired CTX-M-15-type ESBL-producing Escherichia coli meningitis: a case report and literature review.

In this report, a case of community-acquired acute bacterial meningitis (CA-ABM) caused by CTX-M-15-producing Escherichia coli in an elderly male patient was presented in the light of literature. Cultures of cerebrospinal fluid, blood, ear discharge, and stool samples yielded CTX-M-15-producing E. coli in-vitro, which was resistant to the extended-spectrum cephalosporins and ciprofloxacin and susceptible to imipenem, meropenem and amikacin. Meningitis was treated with parenteral meropenem plus parenteral and intraventricular amikacin administration. Since bacterial meningitis is a life-threatening infection, empiric antibiotic therapy with carbapenem can be started before the culture results are obtained, mainly in areas where the ESBL epidemiology is well known.

Antibiotic susceptibility patterns of respiratory isolates of Staphylococcus aureus in a Turkish university hospital.

A total of 391 respiratory isolates of Staphylococcus aureus in Sivas (Turkey) were studied between January 1999-2002. The organisms were cultured from the following specimens: throat (43%), sputum (28%), transtracheal/endotracheal aspirates (27%), and bronchial lavage (2%). The isolates were tested against 11 different antibiotics by a disk diffusion method or standardized microdilution technique. Methicillin-resistant isolates constituted 76.9% of all isolates. Most of the methicillin-resistant isolates (95.1%) were isolated from inpatients. The rate of methicillin-resistant isolates in throat, sputum, and tracheal aspirates was 17.2%, 60.1%, and 68.9%, respectively. The resistance of methicillin-resistant isolates in throat to teicoplanin was 3.4%. The methicillin-sensitive isolates were susceptible to most agents tested, while most methicillin-resistant isolates were resistant to these agents. Overall resistance to erythromycin was 61.9%, tetracycline 56.6%, gentamicin 50.7%, ofloxacin 42.0%, rifampin 40.8%, clindamycin 38.9%, chloramphenicol 19.0%, co-trimoxazole 10.2%, and vancomycin 0%.