Comparison of a novel antigen detection test with reverse transcription polymerase chain reaction assay for laboratory diagnosis of SARS-CoV-2 infection.

Molecular diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by real-time reverse transcription polymerase chain reaction (RT-PCR) in respiratory specimens is considered the gold standard method. This method is highly sensitive and specific but it has some limitations such as being expensive and requiring special laboratory equipment and skilled personnel. RapidFor™ Antigen Rapid Test Kit is a commercially available Ag-RDT which is produced in Turkey and designed to detect the nucleocapsid antigen of SARS-CoV-2 in nasopharyngeal swab samples. The aim of this study was to evaluate the performance of this novel SARS-CoV-2 antigen detection considering the RT-PCR method as the gold standard. Four hundred forty-four nasopharyngeal swab samples which were collected from the patients who met clinical criteria of COVID-19 from ten centers in Turkey between September 2020 and February 2021 were included in the study. All the nasopharyngeal swab samples were tested for SARS-CoV-2 RNA using commercial RT-PCR kits (Bioeksen and A1 Lifesciences, Istanbul, Turkey) according to the manufacturer's instructions. Viral loads were assessed according to the cycle threshold (Ct) values. RapidFor™ SARS-CoV-2 antigen test (Vitrosens Biotechnology, Istanbul, Turkey) was used to investigate the presence of SARS-CoV-2 antigen in all samples following the manufacturer's instructions. Out of 444 nasopharyngeal swab samples tested, 346 (77.9%) were positive and 98 (22.1%) were negative for SARS-CoV-2 RNA by RTPCR. Overall sensitivity of the RapidFor™. Antigen Rapid Test Kit was 80.3% whereas specificity was found to be 87.8%. Positivity rate of rapid antigen test in samples with Ct values over 25 and below 30 was 82.7%, while it increased to 95.7% in samples 20 ≤ Ct < 25 and reached 100% in samples with Ct values below 20. RapidFor™ SARS-CoV-2 Ag test might be a good choice in the screening of symptomatic and asymptomatic patients and their contacts for taking isolation measures early, with advantages over RT-PCR as being rapid, easy and being applicable in every laboratory and even at point of care.

[The Importance of Gram-stained Smears in the Diagnosis of Nocardia Infections]. / Nocardia Enfeksiyonlarinin Tanisinda Gram Boyanmis Yaymalarin Önemi.

Nocardia species are low virulence bacteria found in nature. They can be an infectious agent, especially in patients with risk factors such as underlying immunosuppression, chronic lung disease, and malignancy. They can be easily overlooked because they are not seen frequently and has no pathognomonic symptoms. With this study, it was aimed to draw attention to the importance of microscopic examination of Gram-stained smears in the diagnosis of Nocardia infections in routine microbiology laboratories. Cases in which Nocardia spp. were detected in their clinical samples between November 2014-December 2015 in Hacettepe University Medical Faculty Hospital were included in the study. In the direct microscopic examination of Gram-stained smears of the samples arriving to the laboratory, the incubation periods of the cultures of the samples compatible with Nocardia spp. were extended. Then relevant colonies were identified by conventional microbiological methods and also by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS, bioMerieux, France) automated system. Species-level identification of Nocardia isolates was performed by 16S rRNA gene sequence analysis. To demonstrate the genetic relationship between Nocardia isolates, pulsed-field gel electrophoresis (PFGE) was performed. In vitro susceptibility of the isolates against amoxicillin-clavulanate (AMC), linezolid, moxifloxacin, trimethoprim-sulfamethoxazole (TMP-SXT), amikacin, imipenem, clarithromycin, cefepime, cefotaxime, ceftriaxone, and ciprofloxacin was determined using the gradient strip method (E-test). A total of 19 Nocardia spp. strains were isolated from eight patients. Four cases exhibited repeated growth of Nocardia spp. up to a period of nine months. The most frequently isolated species was N.cyriacigeorgica, which was identified in four cases. Other species isolated from patients were N.asteroides, N.transvalensis, N.farcinicia, and N.asiatica/arthritidis. When the results obtained with DNA sequence analysis and MALDI-TOF MS were compared, 16 (84.2%) of 19 isolates were correctly identified to the genus level and 9 (47.4%) to the species level with MALDI-TOF MS, while three (15.8%) isolates could not be identified, and seven (36.8%) isolates were misidentified. According to the PFGE results, it was determined that the strains isolated from the same patient were genetically identical. All isolates were susceptible to amikacin, cefepime, cefotaxime, ceftriaxone, imipenem, linezolid, and except one isolate to TMP-SXT. Among the study isolates, the most common resistance was against ciprofloxacin (62.5%), followed by clarithromycin (37.5%). N.cyriacigeorgica was determined as the most frequently detected and the most resistant species to antibiotics in the study population. Direct microscopic examination of clinical specimens is one of the most valuable methods for the identification of Nocardia-type bacteria, which is difficult to isolate in microbiology laboratories. With this study, the importance of examining Gram-stained clinical samples was emphasized in the identification of Nocardia species, which can emerge with a wide variety of clinical forms and can be easily overlooked. In addition, antibiotic susceptibility profiles of the isolated bacteria were determinedto contribute to species-specific susceptibility profiles. Accurate identification of Nocardia species will contribute to clinical and epidemiological studies.

Whole-Genome Sequence Analysis of Carbapenem-Heteroresistant Klebsiella pneumoniae and Escherichia coli Isolates.

Carbapenem-heteroresistant isolates can be misclassified as susceptible by in vitro susceptibility tests, leading to treatment failure. The underlying mechanisms of heteroresistance, where the bacterial isolate harbors both resistant and susceptible subpopulations, are poorly understood. The aim of the current study was to clarify molecular mechanisms responsible for carbapenem heteroresistance. Whole-genome shotgun sequencing was performed for both resistant and susceptible subpopulations of three Klebsiella pneumoniae and one Escherichia coli blood isolates, which were identified as carbapenem-heteroresistant by the population analysis profile method. The software from the Center for Genomic Epidemiology was used to identify genomic similarities, antibiotic resistance genes, Multilocus Sequence Typing (MLST), and core-genome MLST(cgMLST). Both susceptible and resistant subpopulations of the E. coli strain had the same MLST profiles. MLST1/2 and cgMLST for E. coli were 46/736 and 119473, respectively. The susceptible and resistant subpopulations of each K. pneumoniae strain exhibited identical MLST profiles. The genetic background for antimicrobial resistance in three K. pneumoniae strains was almost similar between the colonies inside and outside the inhibition zone of each strain, however, there were remarkable differences between the three strains. The blaKPC-2 and blaOXA-48 genes were responsible for carbapenem resistance for E. coli and K. pneumoniae strains, respectively. This is the first study, which has demonstrated similar genotypic and resistant gene profiles in the resistant and susceptible subpopulations of each strain. Additional metabolic and transcriptomic investigations are needed to understand the mechanisms responsible for carbapenem heteroresistance.

[The Use of Resapolymyxin NP Test in Determining the Sensitivity of Colistin in Escherichia coli, and Klebsiella pneumoniae Isolates]. / Escherichia coli ve Klebsiella pneumoniae Izolatlarinda Kolistin Duyarliliginin Belirlenmesinde ResaPolymyxin NP Testinin Kullanimi.

Colistin is used as the last choice of drug in multidrug resistant gram-negative bacilli infections; therefore, accurate detection of colistin susceptibility has gained critical importance. Unfortunately, many of the widely used and practical methods in the clinical laboratory have various limitations for the determination of colistin susceptibility. This situation has led researchers to search for new methods to determine colistin susceptibility. In this study, the performance of the ResaPolymyxin NP test, which was developed for the rapid detection of colistin susceptibility of Pseudomonas aeruginosa and Acinetobacter baumannii isolates, was evaluated for various Gram-negative bacteria for the determination of colistin susceptibility. For this purpose, the colistin MIC values of 105 Escherichia coli, and 196 Klebsiella pneumoniae isolates were determined by broth microdilution (BMD) using cation-adjusted Mueller-Hinton broth and then ResaPolymyxin NP test was applied for each isolate. While 242 (%80.4) of the isolates included in the study were found to be susceptible to colistin with BMD, 214 (71.1%) of the isolates were found as sensitive to colistin with the ResaPolymyxin NP test. The categorical agreement rate for the ResaPolymyxin NP test was 85.7% for E.coli isolates, and 92.3% for K.pneumoniae isolates. The major error rate was 14.7% for E.coli, 10.8% for K.pneumoniae, whereas the very major error rate was 1.8% for K.pneumoniae. For ResaPolymyxin NP test, sensitivity, specificity, positive and negative predictive values were %98,3; %88.0; %66.7; and %99.5. In contrast to the available data about the ResaPolymyxin NP test, both the categorical agreement rate with BMD, and the very major and major error rates varied according to the isolate type, and it was concluded that the test performed relatively better in E.coli and K.pneumoniae isolates. Since the data obtained in this study are quite different from the previously published data, more comprehensive and multicenter studies are needed to evaluate the test effectiveness in order to recommend the use of the ResaPolymyxin NP test in clinical microbiology laboratories.

Molecular characteristics of Staphylococcus aureus strains isolated from nasal samples of sixth year medical students during their pediatric services practices.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) strains are prevalent in healthcare services. Medical students are at risk for MRSA carriage, subsequent infection and potential transmission of nosocomial infection.Few studies have examined MRSA carriage among medical students. METHODS: In this prospective cohort study, between July 2016 and June 2017, two nasal swab samples were taken per student 4 weeks apart during their pediatric internship. MRSA typing was performed by staphylococcal cassette chromosome mec (SCCmec) types, Panton Valentine leukocidin (PVL) encoding genes. RESULTS: A total of 239 sixth year medical students, 164 (68.6%) male (M/F:2.1),with median age 25 years (min-max; 23-65 years) were included in this prospective cohort study. Among 239 students, 17 students (7.1%) were found to be colonized with methicillin-sensitive S. aureus (MSSA) at the beginning of pediatric internship. After 4 weeks, at the end of pediatric internship totally 52 students were found to be S. aureus colonized (21.8%). Three of 52 S. aureus isolates were MRSA (1.3%) and the rest was MSSA (20.5%), all were PVL gen negative. Two of three MRSA isolates were characterized as SCCmec type IV, one isolate was untypeable SCCmec. Nasal carriage of S. aureus increased from 7.1% to 21.5% (p < 0.001). Nasal S. aures colonization ratio was higher in students working in pediatric infectious disease service (p = 0.046). Smoking was found to be associated with a 2.37-fold [95% CI (1.12-5.00); p = 0.023] and number of patients in pediatric services was 2.66-fold [95% CI (1.13-6.27); p = 0.024] increase the risk of nasal S. aureus colonization. Gender was not found to increase risk of MRSA carriage. CONCLUSION: MSSA nasal carriage increased at the end of pediatric internship and significantly high in students working in pediatric infectious diseases services. Smoking and high number of patients in pediatric services significantly increase S.aureus colonization.

Evaluation of a Commercial Broth Microdilution Panel for Colistin Susceptibility Testing of Clinical Isolates of Escherichia coli and Klebsiella pneumoniae.

BACKGROUND: Colistin is among the last resort antibiotics for the treatment of infections caused by multidrug-resistant Gram-negative pathogens. Antimicrobial susceptibility testing of colistin is challenging due to its physicochemical properties. Broth microdilution (BMD) is the recommended method for colistin susceptibility testing. However BMD is not practical for clinical microbiology laboratories as manual preparation of BMD plates is time-consuming and labor intensive. Recently, some more user-friendly BMD products with commercial panels have become available. Our objective was to evaluate the performance of a commercial broth microdilution (BMD) product [Sensititre (Thermo Fisher Scientific)] for colistin MIC determination by comparison with reference BMD method using a collection of E. coli and K. pneumoniae isolates. METHODS: A total of 323 unique patient isolates (102 E. coli, 221 K. pneumoniae) were included in the study. Isolates were stored at -70°C and subcultured twice on sheep blood agar before testing. Colistin MICs of the isolates were determined using Sensititre (a premade BMD product with dried antibiotics) and an 'in-house prepared BMD panel prepared in accordance with CLSI guidelines' (reference method). MIC determination with Sensititre was performed according to manufacturer's instructions. The reference method was performed using untreated 96-well sterile polystyrene plates. Colistin MIC results were interpreted according to EUCAST breakpoints (susceptible, ≤ 2 mg/L; resistant, > 2 mg/L). RESULTS: Overall susceptibility rate of isolates to colistin by reference BMD was 75.9%. Overall categorical agreement (CA), essential agreement (EA), very major error (VME), and major error (ME) rates for Sensititre were 98.5%, 72.5%, 3.8%, and 0.8%, respectively. The CA and EA between Sensititre and reference BMD for the isolates with reference colistin MICs close to the susceptibility breakpoint (2 - 8 mg/L) was 94.2% and 48.1%, respectively. Sensititre yielded a VME rate of 15% and ME rate of 0%, respectively, for this subset of isolates. CONCLUSIONS: In conclusion, Sensititre showed high CA but low EA with reference BMD for entire collection of isolates. The VME rate was just slightly above 3% and ME rate was acceptable. The rates of CA and EA were decreased and the rate of VME was increased when a subset consisting of more challenging isolates was used.

Resistance and heteroresistance to colistin among clinical isolates of Acinetobacter baumannii.

Colistin is one of the most effective alternatives for treating Acinetobacter baumannii infections. The aim of this study was to determine colistin resistance and heteroresistance rates in A. baumannii from clinical samples in Hacettepe University clinical microbiology laboratory between June 2016 and January 2017. A total of 200 isolates were included in the study. In vitro susceptibility to amikacin, gentamicin, ceftazidime, piperacillin/tazobactam, meropenem, ciprofloxacin, and tigecycline were determined by disk diffusion test. Most isolates were multiresistant as they exhibited resistance to aminoglycosides, ß-lactams, and fluoroquinolones. Colistin susceptibility was determined by broth microdilution (BMD) test (EUCAST standards) and was compared with E-test (bioMérieux, France) in 120 isolates. In 14 blood isolates that were susceptible to colistin (MIC ≤ 2 mg/L), heteroresistance was investigated with the population analysis profile (PAP) method. Overall resistance (n = 200) to colistin was 28% by BMD. Among the 120 isolates where the two tests were compared, resistance to colistin was 25.8% versus 4.2% with BMD and E-test, respectively. Three blood isolates (21.4%) were heteroresistant to colistin. With E-test, a majority of the resistant isolates are overlooked and in vitro susceptibility to colistin should be determined with broth dilution method. This is the first study in Turkey reporting heteroresistance in A. baumannii isolates by the PAP method and emphasizes the need to test for heteroresistance in relation to clinical outcome in serious infections due to A. baumannii.

Low prevalence of hypervirulent Klebsiella pneumoniae in Anatolia, screened via phenotypic and genotypic testing.

Hypervirulent Klebsiella pneumoniae (hvKP) strains are associated with vigorous clinical presentation and relapses. Initially reported from Asia, these variants have spread globally and become an emerging agent of significant health threat. This study was carried out to identify hvKP strains in a previously uninvestigated region and to evaluate the impact of commonly-employed phenotypic and genotypic markers as diagnostic assays. A total of 111 blood culture isolates, collected at a tertiary care center was investigated. The hvKP strains were sought by a string test and the amplification of partial magA, rmpA, iucA and peg344. All products were characterized via sequencing. Evidence for hvKP was observed in 10.8% via iucA amplification (7.2%), string test (2.7%) and magA amplification (0.9%). Specific products were not produced by assays targeting rmpA and peg344 genes. Antibiotic susceptibility patterns compatible with possible extensive or pan-antimicrobial resistance was noted in 66.7% of the hvKP candidate strains. Capsule type in the magA positive strain was characterized as K5. We have detected hvKP in low prevalence at a region with no prior documentation. Targetting the aerobactin gene via iucA amplification provided the most accurate detection in this setting. The epidemiology of hvKP in Anatolia requires elucidation for effective control and management.

A case of Raoultella ornithinolytica urinary tract infection in a pediatric patient.

Raoultella ornithinolytica is a Gram-negative, non-motile, encapsulated, biofilm producing, facultative aerobic bacillus and is found in natural environment. Human infections with R.ornithinolytica is rare in children with only five cases having been reported previously. The present case report describes an urinary tract infection caused by R. ornithinolytica that was identified by MALDI-TOF MS and successfully treated with antibiotic therapy in a 6.5-year-old female child.

Six cases during 2012-2015 and literature review of Chryseobacterium indologenes infections in pediatric patients.

Chryseobacterium indologenes is a widespread bacteria in the environment, especially hospitals, and a rarely reported human pathogen. The lowest frequency has been reported in children under 5 years of age. Clinical manifestations of C. indologenes include nosocomial pneumoniae, biliary tract infection, peritonitis, surgical wound infection, intravascular catheter-related bacteremia, cellulitis, and primary bacteremia. There is a knowledge gap in the management of C. indologenes infections, especially pertaining children, because of multiple antibiotic resistance and limited data in the literature concerning effective empirical treatment. In the published literature, a total of 16 cases of C. indologenes infections were reported in the pediatric age group. Herein, we present our experience in 6 children with C. indologenes infections. Early and prompt management of C. indologenes infections, particularly in children with mechanic ventilation, with polymicrobial infections, and under the age of 2 years, is of major importance because these factors seem to have a negative effect on the prognosis of infections caused by C. indologenes. Ciprofloxacin and TPM-SMX may be the best therapeutic choices for a combined initial empirical treatment of the patients.

Vancomycin and daptomycin minimum inhibitory concentration distribution and occurrence of heteroresistance among methicillin-resistant Staphylococcus aureus blood isolates in Turkey.

BACKGROUND: The aim of this study was to determine the distribution of vancomycin and daptomycin MICs among methicillin-resistant Staphylococcus aureus (MRSA) blood isolates, the prevalence of heterogeneous vancomycin-intermediate S. aureus (hVISA) and the relationship between hVISA and vancomycin MIC values. METHODS: A total of 175 MRSA blood isolates were collected from seven university hospitals in Turkey. All isolates were tested for susceptibility to vancomycin and daptomycin by reference broth microdilution (BMD) and by standard Etest method. BMD test was performed according to CLSI guidelines and Etest was performed according to the instructions of the manufacturer. All isolates were screened for the presence of the hVISA by using macro Etest (MET) and population analysis profile-area under the curve (PAP-AUC) methods. RESULTS: The vancomycin MIC50, MIC90 and MIC ranges were 1, 2, and 0.5-2 µg/ml, respectively, by both of BMD and Etest. The daptomycin MIC50, MIC90 and MIC ranges were 0.5, 1 and 0.125 -1 µg/ml by BMD and 0.25, 0.5 and 0.06-1 µg/ml by Etest, respectively. The vancomycin MIC for 40.6% (71/175) of the MRSA isolates tested was >1 µg/ml by BMD. No vancomycin and daptomycin resistance was found among MRSA isolates. Percent agreement of Etest MICs with BMD MICs within ±1 doubling dilution was 100% and 73.1% for vancomycin and daptomycin, respectively. The prevalence of hVISA among MRSA blood isolates was 13.7% (24/175) by PAP-AUC method. MET identified only 14 of the hVISA strains (sensitivity, 58.3%), and there were 12 strains identified as hVISA that were not subsequently confirmed by PAP-AUC (specificity, 92.1%). CONCLUSIONS: Agreement between BMD and Etest MICs is high both for vancomycin and daptomycin. Daptomycin was found to be highly active against MRSA isolates including hVISA. A considerable number of isolates are determined as hVISA among blood isolates. As it is impractical to use the reference method (PAP-AUC) for large numbers of isolates, laboratory methods for rapid and accurate identification of hVISA need to be developed.

Association between osteoprotegerin, fetuin-A, carotid intima media thickness, and urinary albumin excretion in Type 2 diabetes.

AIMS: Vascular calcification and atherosclerosis play a vital role in the development of cardiovascular morbidity and mortality in diabetic patients, especially when complications of diabetic nephropathy occur. Osteoprotegerin (OPG) and fetuin-A are two markers of vascular calcification. We evaluated the association between these vascular markers and urinary albumin excretion in diabetic patients. METHOD: Three groups were arranged containing 40 patients: normoalbuminuric (Group 1), microalbuminuric (Group 2), and macroalbuminuric (Group 3). In addition to the obtained data, levels of hs-CRP (high sensitivity-CRP) and homocysteine were examined. RESULTS: OPG levels of patients in Group 2 were higher than in Group 1 (p = 0.058). OPG levels in Group 3 were lower than in Groups 1 or 2 (p = 0.014 and 0.000, respectively). Levels of fetuin-A in Group 2 were determined to be lower than in Groups 1 and 3 (p = 0.001 and 0.000, respectively). Carotid intima media thickness (CIMT) in Group 3 was higher than in Group 1 (p = 0.002). CIMT in Group 2 was also higher than in Group 1 (p = 0.039). A positive correlation between fetuin-A and OPG was found (p = 0.012, r = 0.393). Additionally, a positive correlation between hs-CRP and fetuin-A in Group 2 (p = 0.020, r = 0.367) and a negative correlation between hs-CRP and OPG in Group 3 (p = 0.036, r = -0.333) were observed. CONCLUSIONS: The differences found between albuminuria and OPG or fetuin-A may be due to the different doses and variety of medications the patients received, in addition to genetic and racial factors. So far, in our country, polymorphisms related to OPG and fetuin-A have not been defined. Further detailed studies about polymorphisms will have additional value.

[Evaluation of methicillin-resistant Staphylococcus aureus bacteremia and comparison of prognosis according to vancomycin MIC values: experience of the last ten years]. / Metisiline dirençli Staphylococcus aureus bakteriyemisinin incelenmesi ve vankomisin MIK degerlerine göre prognozun karsilastirilmasi: Son on yillik deneyim.

Hospital acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are important health problems. Mortality and morbidity rates associated with MRSA infections are increasing with mortality rates being higher for MRSA bacteremia than the other clinical presentations of MRSA infections. Initiation of treatment immediately and use of appropriate antibacterial agents may lead to better clinical outcomes in MRSA bacteremia. The aims of this study were to evaluate the treatment and clinical outcomes of patients with MRSA bacteremia in a tertiary care hospital in Ankara, Turkey. Two hundred forty seven MRSA strains isolated from blood cultures at Hacettepe University Faculty of Medicine, Clinical Microbiology Laboratory between January 2000-December 2010, were evaluated retrospectively. Demographic characteristics, duration of bacteremia, types and duration of antibiotic treatment, presence of other pathogens and all other necessary information were collected from patients' registry. One hundred eighty four patients who had clinically significant bacteremia were analyzed. The mean age of the patients was 55 ± 17 years, of them 44.6% were female and 55.4% were male. The median length of hospital stay was 61 days. The median duration for the development of MRSA bacteremia from the time of admission was 23 days. Overall mortality rate was 54.9%, and mortality rate due to MRSA bacteremia was 19%. The rate of treatment success was 81%. There were 3 (1.6%) patients with vancomycin MIC value of 0.5 mg/L, 140 (76.1%) patients with 1 mg/L and 41 (22.3%) patients with 2 mg/L. The median duration from the time of MRSA bacteremia detection to the time of death was shorter in unsuccessfully treated group than successfully treated group (7 days vs. 30 days, p< 0.001). Thirty days mortality rate was higher in unsuccessfully treated group than successfully treated group (94.3% vs. 50.7%, p< 0.001). The median time interval between positive and negative cultures was 9.5 days. Number of patients with MRSA bacteremia had been decreasing for the last five years (36 patients in 2006, 18 in 2007, 16 in 2008, 12 in 2009 and one in 2010). In multivariate logistic regression analysis, it was shown that, intubation (OR: 5.086, 95% CI: 2.094-12.351; p< 0.001) and malignancy (OR: 2.789, 95% CI: 1.185-6.564; p= 0.019) were independent risk factors for mortality. In this study, it was shown that mortality rate was high in MRSA bacteremia and high MIC value was not an independent risk factor for mortality. It was also noted that when there was no clinical response to vancomycin, the therapy should be changed immediately. To decrease MRSA bacteremia rates in the hospital adherence to rules of infection control and prevention proved to be important factors.

Serotype distribution of Streptococcus pneumoniae and pneumococcal vaccine coverage in adults in Turkey between 2015 and 2018.

OBJECTIVE: To evaluate the serotype distribution and antibiotic resistance in pneumococcal infections in adults and to provide a perspective regarding serotype coverage of both current and future pneumococcal vaccines. PATIENTS AND METHODS: This passive surveillance study was conducted with the Streptococcus pneumoniae strains isolated from the specimens of patients with pneumonia (materials isolated from bronchoalveolar lavage), bacteraemia, meningitis, pleuritis and peritonitis between 2015 and 2018. Serogrouping and serotyping were performed by latex particle agglutination and by conventional Quellung reaction using commercial type-specific antisera, respectively. The strains were analysed for penicillin, cefotaxime, erythromycin and moxifloxacin susceptibilities by E-test. RESULTS: In the whole study group (410 samples from adults aged ≥18 years), the most frequent serotypes were 3 (14.1%), 19 F (12%) and 1 (9.3%). The vaccine coverage for PCV13, PCV15, PCV20 and PPV23 was 63.9%, 66.6%, 74.1% and 75.9%, respectively, in all isolates. Penicillin non-susceptibility in invasive pneumococcal disease (IPD) was 70.8% and 57.1% in the patients aged <65 and ≥65 years, respectively. About 21.1% and 4.3% of the patients with and without IPD had cefotaxime resistance. Non-susceptibility to erythromycin and moxifloxacin was 38.2% and 1.2%, respectively. CONCLUSIONS: The results revealed that novel PCV vaccines may provide improved coverage as compared with the currently available vaccine, PCV13. The significant antibiotic resistance rates imply the need to extend the serotype coverage of the vaccines. Continuing the surveillance in pneumococcal diseases is critical to explore the serotype distribution and incidence changes of IPD cases in the population and to inform policy makers to make necessary improvements in the national immunization programmes.Key messagesThis multicentre study demonstrated the most recent serotype distribution and antibiotic resistance in adult population in Turkey.Shifting from PCV13 to novel conjugated vaccines will significantly increase the coverage.Continuing the surveillance in pneumococcal diseases is critical to explore the serotype distribution changes and the incidence of cases with invasive pneumococcal disease in the population.

[Investigation of SCCmec types and Panton-Valentine leukocidin in community-acquired and nosocomial Staphylococcus aureus strains: comparing skin and soft tissue infections to the other infections]. / Toplumdan Kazanilmis ve Nozokomiyal Staphylococcus aureus Suslarinda SCCmec Tiplerinin ve Panton-Valentine Lökosidin Varliginin Arastirilmasi: Deri ve Yumusak Doku Enfeksiyonlari ile Diger Enfeksiyonlarin Karsilastirilmasi

Infections due to methicillin-resistant Staphylococcus aureus (MRSA) are important health care problems since they are usually multidrug resistant. Although MRSA is isolated especially from nosocomial infections, community-acquired MRSA infections are increasing. Methicillin resistance is due to the expression of mecA gene, which is located on SCCmec gene cassette. Different SCCmec types can be detected in hospital-acquired and community-acquired (CA-) MRSA strains. CA-MRSA strains might harbour Panton-Valentine leukocidin (PVL), an important virulence factor in skin and soft tissue infections. Strains carrying PVL has the ability to penetrate undamaged skin and cause more severe infections. The aim of this study was to detect SCCmec types and PVL gene in S.aureus strains isolated from skin and soft tissue infections and to compare with strains isolated from other infections in a university hospital in Ankara, Turkey. S.aureus strains isolated from skin and soft tissue infections (n= 285) and a control group consisting of 161 strains isolated from other infections (53 blood, 48 lower respiratory tract samples, 30 sterile body fluids, 30 genitourinary tract samples) chosen by stratification and random selection method, were included in the study. Among skin and soft tissue infection strains 46.7% were from the hospitalized patients and 48.4% of skin and soft tissue infection strains were from female patients. The mean age of the skin and soft tissue infection patients was 45.5 years. Among the control strains 60.9% were from the hospitalized patients and 41.6% of the control patients were female. The mean age of the control patients was 50.2 years. Strains were identified by the Phoenix system (Becton Dickinson, USA) and identification was confirmed by tube coagulase test. Methicillin resistance was determined by the Phoenix system which determines both oxacillin and cefoxitin minimum inhibitor concentrations and, confirmed by oxacillin agar screening and/or cefoxitin disk diffusion test. All isolates were screened for the presence of mecA and PVL genes and SCCmec types were determined by PCR. MRSA constituted 20.3% (n= 58) of skin and soft tissue infection isolates and 24.2% (n= 39) of the control group. Of the 97 MRSA, 85 had a SCCmec type III-like pattern with an additional dcs region, three had type IV, three had type IIIa, one had type IIIb, one had type II and four could not be typed. The difference between SCCmec type distribution in skin and soft tissue infection and other infections' (control) groups was not statistically significant (p> 0.05). Two of the three SCCmec type IV strains were type IVa. Ten (2.2%) PVL positive strains, three of which were from the control group; were all methicillin susceptible S.aureus (MSSA). Although PVL positive MRSA was not common, detection of SCCmec type IVa, a marker for CAMRSA, and PVL positive MSSA strains which might act as a reservoir for PVL positive MRSA, indicated the importance of ongoing surveillance for MRSA.

A twenty years' results of the antimicrobial resistance profile and multidrug resistance trend of invasive Streptococcus pneumoniae isolates recovered from adult patients in Turkey: A literature review.

PURPOSE: The aim of this study is to analyze antimicrobial resistance and multidrug (MDR)/extensively (XDR) resistance trend among Streptococcus pneumoniae isolates causing invasive disease in adult patients. METHODS: We analyzed antimicrobial resistance and multidrug resistance trend among invasive S.pneumoniae isolates recovered from adult patients (≥18-years) in a tertiary University Hospital, Turkey between 1996 and 2018. The antibiotic susceptibility pattern was determined by using gradient-test for penicillin and cefotaxime and disk-diffusion method for other antibiotics. RESULTS: A total of 272 isolates (74.3% from the bloodstream) of S. pneumoniae were collected during the study period. The highest non-susceptibility rate was obtained for tetracycline (63.5%), followed by trimethoprim/sulfamethoxazole (48%), penicillin-oral (30.4%), erythromycin (21.7%), clindamycin (15.8%), ciprofloxacin/levofloxacin (5.9%), penicillin-parenteral (5.5%), cefotaxime (2.2%), and rifampisin (1.8%), respectively. No resistance was observed against vancomycin during the years studied. Over the study period, a significant increase in the rate of antimicrobial resistance among invasive pneumococcal isolates was detected with a peak at period 2014-2018. Although there was an increase in the rates of non-susceptibility to penicillin oral, parenteral penicillin, cefotaxime, erythromycin and clindamycin in adult patients, the results were not statistically significant except erythromycin. Prevalence of MDR and XDR S. pneumoniae were 29% and 9.2% respectively. When the serotypes of MDR isolates were examined, it was noted that serotype 19F (35%) and 14 (12.5%) were the most common. CONCLUSIONS: Our study showed an overall increase in non-susceptibility rates of penicillin and erythromycin in invasive S.pneumoniae isolates recovered from Turkish adult patients. Although the prevalence of MDR showed fluctuation between years, the incidence of MDR remained stable. These data indicate the necessity for continuous monitoring and assessment of serotypes and antimicrobial resistance trends in S.pneumoniae in different age groups at both the national and the regional levels as it can be affected by the serotypes dominant in that region, rational use of antibiotics and the vaccination programs.

Factors Associated with Gram-Negative Bacteremia and Mortality in Neutropenic Patients with Hematologic Malignancies in a High-Resistance Setting.

Objective: Patients with hematological malignancies (HMs) have a substantial incidence of febrile neutropenic episodes. Gram-negative bacteremia (GNB) is still the major cause of these episodes. We evaluated the factors associated with GNB and mortality of bacteremic patients with HMs in a high-resistance setting. Materials and Methods: We conducted a prospective cohort study from March 2018 to June 2019 with 66 bacteremic and 132 non-bacteremic patients. Regression analyses were used to identify factors associated with GNB and 30-day mortality. Results: The mean age was 53.83±15.21 years, and 129 (65.2%) of the patients were male. In multivariable analysis, factors independently associated with GNB were male gender, duration of hospitalization and neutropenia before the febrile neutropenic episode, leukemias and allogeneic transplant recipients, radiotherapy, receiving glucocorticosteroids, colonization with resistant microorganisms. All-cause mortality and 30-day mortality were 47.0% and 30.3% in cases of GNB, compared to non-bacteremic controls 25.0% and 10.6%, respectively. Sepsis, duration of hospitalization before the febrile neutropenic episode, carbapenem-resistant GNB, and inappropriate empirical antibiotic treatment was found as factors associated with 30-day mortality. Prior antibiotic exposure particularly beta-lactamase inhibitor combinations and carbapenems during the past 30 days was more frequent in the bacteremic group. An increasing trend was observed in multidrug-resistant (MDR) bacteria (p=0.03) and carbapenem-resistant Enterobacterales (p=0.02) over the years. Conclusion: By considering the risk factors associated with GNB and 30-day mortality that we detected in our study among neutropenic patients, a personalized approach for the management of febrile neutropenic patients can be designed by means of an effective antimicrobial stewardship program including the appropriate use of broad-spectrum antibiotics.

A retrospective observational cohort study of the clinical epidemiology of bloodstream infections due to carbapenem-resistant Klebsiella pneumoniae in an OXA-48 endemic setting.

This study aimed to characterize the epidemiology and clinical outcomes of patients with bloodstream infections (BSIs) due to carbapenem-resistant Klebsiella pneumoniae (CRKP) in an OXA-48-predominant environment. This was a retrospective single-centre cohort study including all consecutive patients with CRKP BSIs treated between 1 January 2014 and 31 December 2018. Multivariate analysis, subgroup analysis and propensity-score-matched analysis were employed to analyse 30-day mortality as the primary outcome. Clinical cure at day 14 was also analysed for the whole cohort. In total, 124 patients with unique isolates met all the inclusion criteria. OXA-48 was the most common type of carbapenemase (85.5%). Inappropriate therapy was significantly associated with 30-day mortality [70.6% vs 39.7%, adjusted odds ratio (aOR) 4.65, 95% confidence interval (CI) 1.50-14.40, P=0.008] and 14-day clinical failure (78.5% vs 56.2%, aOR 3.14, 95% CI 1.09-9.02, P=0.033) in multivariate analyses. Among those treated appropriately, the 30-day mortality rates were similar in monotherapy and combination therapy arms (OR 2.85, 95% CI 0.68-11.95, P=0.15). INCREMENT CPE mortality score (aOR 1.16, 95% CI 1.01-1.33, P=0.029), sepsis at BSI onset (aOR 2.90, 95% CI 1.02-8.27, P=0.046), and inappropriate therapy (aOR 4.65, 95% CI 1.50-14.40, P=0.008) were identified as independent risk factors for 30-day mortality. Colistin resistance in CRKP had no significant impact on 30-day mortality. These results were also confirmed in all propensity-score-matched analyses and sensitivity analyses. Appropriate regimens were associated with better clinical outcomes than inappropriate therapies for BSIs with CRKP predominantly possessing OXA-48.

Sensitivity Affected by Disease Severity and Serum Sampling Time: a Performance Evaluation of Six SARS-CoV-2 Antibody Immunoassays.

Comparative validation and clinical performance data are essential for the reliable interpretation of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibody test results. This study aimed to assess the performance of six SARS-CoV-2 IgG immunoassays in the context of different disease severities. Four automated chemiluminescence immunoassays (Access [Beckman Coulter], Architect [Abbott], Atellica-IM [Siemens], and Elecsys [Roche]) as well as two ELISA assays (SARS-CoV-2 IgG-S1-based and NCP IgG [Euroimmun]) were evaluated using samples from 143 patients as well as 50 pre-pandemic control serum samples. Accuracy and precision tests were performed for validation purposes. Overall sensitivity ranged between 73.38-88.65% and was higher in spike protein-based assays, while the specificity was ≥98% in all immunoassays. The clinical performance of the immunoassays differed depending on disease severity and target antigen. For instance, the IgG response was lower for samples taken <20 days post-symptom onset (87.30%) compared with those taken ≥20 days post-symptom onset (94.80%). Moreover, moderate disease levels led to the highest levels of IgG. Higher levels of antibodies were detected in the clinically moderate disease group. In asymptomatic and mild groups, more antibody positivity was detected with spike protein-based assays. All the assays tested could be used to detect SARS-CoV-2 IgG. However, spike-based assays revealed relatively higher sensitivity rates than nucleoprotein-based assays, particularly in cases of asymptomatic and mild disease.

Lack of Candida africana and Candida dubliniensis in vaginal Candida albicans isolates in Turkey using HWP1 gene polymorphisms.

Candida africana differs from the common strains of C. albicans and C. dubliniensis morphologically, physiologically, genetically, and, in particular, clinically. This fungal pathogen is primarily recovered from genital specimens, especially in vaginal specimens. In this investigation, we reexamined 195 vaginal C. albicans isolates for the presence of C. africana and C. dubliniensis by using hyphal wall protein 1 (HWP1) gene polymorphisms. All study isolates were confirmed to be C. albicans, and none were verified as either C. africana or C. dubliniensis. In conclusion, the HWP1 gene polymorphisms offer a useful tool in the discrimination of C. africana, C. albicans, and C. dubliniensis. Further studies may highlight the pathogenesis and importance of this yeast in vulvovaginal candidiasis.