[Recent Advances in Laboratory Diagnosis of Syphilis]. / Sifilisin Laboratuvar Tanisinda Güncel Gelismeler.

Syphilis is a sexually transmitted disease caused by Treponema pallidum subsp. pallidum. This historical disease has diverse clinical manifestations making laboratory testing crucial for optimal patient management. Direct detection of T.pallidum by dark-field microscopy is possible when lesions are present. Culture of the bacteria is complex and not performed routinely. There is no well-validated commercially available polymerase chain reaction (PCR) test. Serological tests are currently the most common diagnostic methods adapted in clinical laboratories. They provide a presumptive diagnosis and used for screening, diagnosis, and follow-up of the treatment. They are divided into two groups, named as nontreponemal and treponemal tests and performed by the application of the traditional algorithm, the reverse sequence algorithm or European Centre for Disease Prevention and Control (ECDC) algorithm. The traditional algorithm starts with a nontreponemal test and a reactive result is confirmed with a treponemal test. In the reverse sequence algorithm, a treponemal test is used for screening and a reactive result is confirmed by a quantitative nontreponemal test. When the nontreponemal test is negative, a second different treponemal test preferably T.pallidum particle agglutination test (TPPA) is used. The ECDC algorithm recommends screening by a treponemal test such as T.pallidum enzym immunoassay (TP-EIA), T.pallidum chemiluminescence immunoassay (CIA) and if reactive, a reflex confirmatory treponemal test is performed. The treponemal tests become reactive a few weeks after infection and remain reactive even after successful treatment. The nontreponemal tests are used to assess disease activity and response to therapy. Serological tests have many limitations such as false-positivity, falsenegativity in various stages of the disease and also challenging difficulties when evaluating response to therapy. In recent years, rapid syphilis tests which are mostly treponemal-specific tests have been developed for high-prevalence populations in resource limited settings. There has been requirement for the utility of standart PCR and IgM testing in the diagnosis of congenital syphilis and neurosyphilis cases. In this review article, it was aimed to present the diagnostic tests, the algorithms, the correct indications for testing and interpretation of the test results to the likely corresponding clinical stage of the disease with in the perspective of recent advances.

[Investigation of the Frequency of Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis and Mycoplasma genitalium in Men Living with HIV in Terms of Sociodemographic Characteristics and Behavioral Risk Factors]. / HIV ile Yasayan Erkeklerde Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis ve Mycoplasma genitalium Sikliginin Sosyodemografik Özellikler ve Davranissal Risk Faktörleri ile Birlikte Arastirilmasi.

The aim of this study was to investigate the frequency of Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis and Mycoplasma genitalium in men living with HIV in terms of sociodemographic characteristics and behavioral risk factors. In this cross-sectional, single center study, all HIV-infected male patients, aged ≥ 18 years, including those being followed-up (n= 142) and the new admissions (n= 16) at Hacettepe University, Department of Infectious Diseases between March 1st, 2017 and May 1st, 2018 were included. After obtaining the informed consent form; age, follow-up days in STI-clinic, marital status, education, employment status; STI-related sign and symptoms, prior STI diagnosis, multiple sexual partners during the last year, exchanging sex for money, sexual orientation, drug use, condom use with regular and casual partner and also risk factors regarding partners were inquired as behavioural risk factors. A sample of first-voided urine of each participant was tested for the presence of Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis and Mycoplasma genitalium by using nucleic acid amplification test (NAAT) (BD-MAX system, BD Diagnostics, USA) and BD MAX Mycoplasma-Ureaplasma-OSR for BioGX, (BD Diagnostics, The Netherlands). All participants living with HIV, men who have sex with men (MSM) and heterosexual men were grouped as STI-positive and STI-negative and compared. For all statistical analysis, SPSS 24 software was used. During the period of 14 months; the data was determined as follows: median follow-up time was 1138 (IQR= 159.5- 1494.5) days, median age was 35 (IQR= 28-42) years, 73.3% were single, 68.3% were at least college graduates or had higher educational attainment, 78.1% were currently employed. Of the participants, 26.9% reported STI-related sign and symptoms, 50.0% at least one STI episode in the past. Nine (5.6%) M.genitalium, five (3.1%) N.gonorrhoeae, and four (2.5%) C.trachomatis were detected in the urine samples of 17 (10.7%) individuals. N.gonorrhoeae and C.trachomatis were detected simultaneously in only one patient's urine sample. STI-positive patients (n= 17) were determined to be younger compared to STI-negative group [(p= 0.02; 27 years (IQR= 24-37) vs 35 years (IQR= 28-42)], had prominent STI-related signs and symptoms (p< 0.001) and had more multiple sexual partners (p= 0.03). The median CD4+ T lymphocyte count were relatively lower (p= 0.03) in STI-positive patients and plasma HIV RNA level was higher compared to the STI-negative participants (p= 0.05). STI-positive MSM group were younger [p= 0.01; 26 years (IQR= 23.5-29) vs 33 years, (IQR= 28-40)], STI-related signs and symptoms were more prominent (p= 0.02), the frequency of exchanging sex for money/drugs among their partners (p= 0.03) was higher compared to their STI-negative counterparts. Among STI-positive heterosexual patients, the presence of STI-related signs and symptoms (p= 0.04), drug use among their partners (p= 0.04) and plasma HIV RNA level (p<0.01) were significantly higher. STI was identified as an important health problem in this series of men living with HIV, 63.0% of whom had MSM and had a relatively high education level and socioeconomic status. Young age, having multiple partners, drug use, exchanging sex for money/drugs were prominent among the participants and their partners. Public health studies should focus on preventing STIs in young people living with HIV who have behavioral risk factors.

Correlation of Treponemal Chemiluminescent Microparticle Immunoassay Screening Test Signal Strength Values With Reactivity of Confirmatory Testing.

BACKGROUND: Automated chemiluminescent microparticle immunoassays (CMIAs) are the most common first step at high-volume laboratories for syphilis screening. If the initial screening test is reactive, 1 more treponemal test is required, resulting in increased cost. In this multicenter study, we aimed to determine the correlation between the CMIA signal-to-cutoff ratio (S/Co) and the confirmatory tests to reduce unnecessary confirmatory testing. METHODS: Eight hospitals from 5 provinces participated in this study. All laboratories used Architect Syphilis TP CMIA (Abbott Diagnostics, Abbott Park, IL) for initial screening. Treponema pallidum hemagglutination (TPHA), rapid plasma reagin (RPR), and fluorescent treponemal antibody absorption (FTA-ABS) were used as confirmatory tests according to the reverse or European Centre for Disease Prevention and Control algorithms. A receiver operating characteristic analysis was used to determine the optimal S/Co ratio to predict the confirmation results. RESULTS: We evaluated 129,346 serum samples screened by CMIA between January 2018 and December 2020. A total of 2468 samples were reactive; 2247 (91%) of them were confirmed to be positive and 221 (9%) were negative. Of the 2468 reactive specimens, 1747 (70.8%) had an S/Co ratio ≥10.4. When the S/Co ratios were ≥7.2 and ≥10.4, the specificity values were determined to be 95% and 100%, respectively. In a subgroup of 75 CMIA-positive patients, FTA-ABS was performed and 62 were positive. Among these FTA-ABS-positive patients, 24 had an S/Co ratio <10.4, and negative TPHA and RPR. CONCLUSIONS: We propose a potentially cost-effective reverse screening algorithm with a treponemal CMIA S/Co ratio ≥10.4, obviating the need for secondary treponemal testing in about 71% of the screening-reactive samples. This would substantially reduce the confirmatory testing volume and laboratory expenses. However, in high-risk group patients with CMIA positive results, S/Co ratio <10.4, and negative TPHA and RPR, FTA-ABS may be used for confirmation.

[Longitudinal Assessment of Anti-Spike-1 antibody Responses in a Group of Hospitalized Patients with SARS-CoV-2 Infection]. / Hastaneye Yatan SARS-CoV-2 Enfeksiyonlu Bir Grup Hastanin Anti-Spike-1 Antikor Yanitlarinin Boylamsal Degerlendirilmesi.

The coronavirus disease-2019 (COVID-19) has become a global cause of death/injury, particularly for those with limited access to vaccination programs and healthcare systems. The risk of re-infection is not negligible due to the emergence of new variants and the decrease in immunity of those who have recovered COVID-19 before. In this study, it was aimed to show longitudinally the change in antibody levels of patients hospitalized for COVID-19 who had an antibody response in the early stages of their infection and to reveal a response pattern that would help to predict patients whose antibody responses decreased or persisted over time. This observational, single-center study included 38 non-critical patients admitted to COVID-19 wards. Anti-spike-1 IgG levels were investigated by the "enzyme-linked immunosorbent assay (ELISA)" method in two different samples taken at different times in each patient. Two distinct anti-spike-1 IgG antibody response patterns were detected in the study; the first pattern was that with low antibody production at first who had an increase in antibody levels after an average of six months, and the second pattern was that the initially high antibody levels decreased after an average of six months. This paradoxical kinetic may blur physicians' predictions of antibody response. In general, anti-spike-1 antibody levels showed a moderate decrease after six months, but production seems to continue (mean ∆IgG= -0.77; σ= 4; p= 0.24). Higher antibody levels were observed at the beginning in patients with concomitant bacterial pneumonia (mean initial IgG= 7.67; σ= 3.54) (p= 0.03). Although the production of S1-IgG in patients recovered from severe acute respiratory system coronavirus2 (SARS-CoV-2) was modestly reduced compared to the beginning measurements, the production in general persisted during the study period. It appears that IgG responses increase or remain constant in individuals with relatively low IgG index values when controlled after an average of 180 days, while IgG tends to decrease in individuals with high IgG index values.

[Comparison of immunochromatographic (IC) and real-time polymerase chain reaction (Rt-PCR) tests for screening Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma spp. and Mycoplasma spp. in HIV-infected men]. / HIV ile enfekte erkeklerde Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma spp. ve Mycoplasma spp. varliginin aranmasinda Immünokromatografik (IK) ve Gerçek Zamanli Polimeraz Zincir Reaksiyonu (Rt-PCR) testlerinin kiyaslanmasi.

Laboratory testing is critical for sexually transmitted infections (STIs) as most of the infected people usually have no symptoms. It is known that having HIV and STI coinfection increases the risk of HIV transmission. Sensitive tests are required for the infection control. The aim of this study was to compare the 2 different diagnostic tests-an immunochromatographic (IC) test and a real-time polymerase chain reaction (Rt-PCR) assay-for screening Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma spp. and Mycoplasma spp. in HIV-infected men. The tests were evaluated in terms of sensitivity, specificity, rapidity, sample types and cost per test. Eighty HIV-infected adult men who were admitted to Hacettepe University Faculty of Medicine Hospital STIs Outpatient Clinic between October 2017-April 2018 were included in the study. Urine and urethral swab samples were collected from each patient. Urine samples were tested by BDMAX (Becton-Dickinson, Canada) assay, Chlamydia antigen cassette test (Monlab, Spain) and Mycoview test (Zeakon, France). Urethral swabs were tested by Gonorrhoeae cassette test (Monlab, Spain). In 18 (22.5%) of the 80 HIV-infected individuals, the presence of at least one of the four agents was detected by Rt-PCR method. A total of 23 agents were reported as one N.gonorrhoeae (1/80), two C.trachomatis (2/80), seven Mycoplasma spp. (7/80), 13 Ureaplasma spp. (13/80). In five (27.7%) patients, Ureaplasma spp. and Mycoplasma spp. were detected simultaneously. Twelve of 23 bacteria detected by Rt-PCR were also detected by IC tests; however, the remaining 11 bacteria (one N.gonorrhoeae, two C.trachomatis, four Ureaplasma spp., four Mycoplasma spp.) were not detected. When IC tests were compared to the gold standard test Rt-PCR, the sensitivity was 47.8% (11/23) and the positive-predictive value was 100% (11/11). Sixteen patients had STI-related signs and symptoms whereas 64 were asymptomatic. Only two of the 18 men with positive-Rt-PCR test results had STI-related symptoms. It was concluded that all individuals with risky behaviours should undergo STIs screening regardless of their symptoms. As obtaining urethral samples could create difficulty for the patients as well as for the physicians, using urine samples determined to be more convenient. In our study the sensitivity of IC tests found to be insufficiently low. It was concluded that in STI screening the use of Rt-PCR method, which has high sensitivity, specificity and ability to give results on the same day although a high cost test could be preferred on high risk groups such as HIV-infected individuals with no signs of infection.

[Various antibiotic combinations against carbapenem resistant Acinetobacter baumannii infections and in vitro synergy test results (2002-2016)]. / Karbapeneme dirençli Acinetobacter baumannii enfeksiyonlarinin tedavisinde kullanilan çesitli antibiyotik kombinasyonlari ve in vitro sinerji test sonuçlari (2002-2016).

Carbapenem resistant Acinetobacter baumannii is a bacterium that causes various hospital acquired infections, primarily ventilator-associated pneumonia and bloodstream infections. The multidrug resistance problem of the bacteria all over the world, is also a problem in our center. As the treatment options are decreasing combination therapies become a current issue. It is believed that in vitro synergy tests may guide to the selection of antibiotic combinations. The aim of this study was to present the antibiotic combinations used in the treatment of carbapenem resistant A.baumannii infections and the synergy test results of these combinations. A total of 71 carbapenem-resistant A.baumannii isolates from various clinical samples of patients in Hacettepe University Adult and Oncology Hospitals was included in the study. All isolates were from nosocomial infections that were being requested for synergy testing by the consulting physicians in the Department of Infectious Diseases and Clinical Microbiology between January 2002 and December 2016. Only one isolate from one patient was included in the analysis. The synergy test for these isolates was performed by E-test method. Of the total, 41 (58%) isolates were from various clinical samples of patients in intensive care units and 30 (42%) were from patients in different wards. Twenty-three of the isolates were obtained from bronchoalveolar lavage (BAL) fluid, 18 from pus, 14 from deep tracheal aspirate, 6 from central venous catheter, 5 from blood and 5 from other various samples. The fractional inhibition concentration (FIC) index for each combination was calculated and the results were interpreted as synergistic, additive, indifferent and antagonist. A total of 38 different combinations of antibiotics were tested. According to the frequency of synergistic activity, the combinations were; meropenem-colistin (11/12), meropenem-amikacin (7/9), meropenem-tobramycin (9/13), rifampicin-colistin (7/11), cefaperazone-sulbactam-tobramycin (8/16) and sefaperazon-sulbactam-amikacin (5/10). The most common antagonistic combinations were tigecyclin-colistin (2/6), meropenem-tobramycin (3/13), cefepim-tobramycin (4/19), rifampicin-colistin (2/11) combinations. In our center, different combinations of antibiotics are being used for the treatment of carbapenem-resistant A.baumannii due to the changing and increasing antibiotic resistance of the bacteria over the years. Sensitivity tests as well as synergy tests are used when selecting different combinations of antibiotics. However generalizability of the synergistic effect of combinations is limited. It is important to repeat these studies at regular intervals. In addition there is also a need for further studies to evaluate the correlation between in vitro laboratory results and in vivo clinical compliance.

Epidemiology and susceptibility of pathogens from SMART 2011-12 Turkey: evaluation of hospital-acquired versus community-acquired urinary tract infections and ICU- versus non-ICU-associated intra-abdominal infections.

Objectives: To describe the epidemiology and susceptibility of pathogens (including ESBL producers) from hospital-acquired (HA) versus community-acquired (CA) urinary tract infections (UTIs) and ICU- versus non-ICU-associated intra-abdominal infections (IAIs) in Turkey as a part of the SMART study. Methods: : For this report, Gram-negative pathogens (363 from UTIs and 458 from IAIs) were collected in 2011 and 2012 at six hospitals in Turkey. HA versus CA UTIs and ICU- versus non-ICU-associated IAIs were compared for the species isolated, percentage of ESBL-positive isolates by species and susceptibility for overall and individual Gram-negative species. Results: : Escherichia coli was the most common pathogen identified in HA (40.2%) and CA (73.9%) UTIs and ICU-associated (25.8%) and non-ICU-associated (43.3%) IAIs. The rate of ESBL-positive E. coli was significantly higher in HA than in CA UTIs (50.5% versus 38.2%, P < 0.001) and in non-ICU-associated than in ICU-associated IAIs (52.5% versus 29.2%, P = 0.029). Of the drugs studied, only amikacin was active against ≥90% of pathogens in UTIs, while ertapenem, imipenem and amikacin were active against ≥90% of E. coli ; and imipenem, amikacin and cefoxitin were active against ≥90% of Klebsiella pneumoniae in IAIs. Conclusions: Our findings demonstrated that E. coli continues to be the principal pathogen of UTIs and IAIs in Turkey. Along with a high rate of ESBL-positive isolates, high antimicrobial resistance among Gram-negative bacilli from either UTIs or IAIs was noted particularly in the case of HA UTIs and ICU-associated IAIs, with a higher likelihood of carbapenem- or amikacin-based therapy to provide the broadest activity against bacterial pathogens.

[Risk factors and antibiotic use in methicillin-resistant Staphylococcus aureus bacteremia in hospitalized patients at Hacettepe University Adult and Oncology Hospitals (2004-2011) and antimicrobial susceptibilities of the isolates: a nested case-control study]. / Hacettepe Üniversitesi Eriskin ve Onkoloji Hastanelerinde yatan hastalarda saptanan metisiline dirençli Staphylococcus aureus bakteriyemilerinde risk faktörleri (2004-2011), antibiyotik kullanimi ve izolatlarin antimikrobiyal duyarliliklari: Yuvalandirilmis olgu-kontrol çalismasi

The aim of this study was to evaluate methicillin-resistant Staphylococcus aureus (MRSA) bacteremia cases who were followed at the Infectious Diseases Unit of Internal Medicine Department, at Hacettepe University Adult and Oncology Hospitals between January 2004-December 2011. A total of 198 patients, of them 99 had positive MRSA blood cultures (case group), and 99 without MRSA bacteremia (control group) who were selected randomly among patients at the same wards during the same time period, were included in the study. Demographic data, risk factors for MRSA bacteremia and antibiotic use of case (60 male, 39 female; mean age: 59.37 ± 16.96 yrs) and control (60 male, 39 female; mean age: 59.11 ± 17.60 yrs) groups were obtained from the patient files and the hospital data system and were compared. Methicillin susceptibility was determined by the cefoxitin (30 µg, BD, USA) disc diffusion method and confirmed by mecA PCR test. Antimicrobial susceptibilities were also determined by disc diffusion and Etest (BioMerieux, France) methods according to CLSI guidelines. There was no statistically significant difference between the two groups according to age, gender, presence of an underlying chronic disease, burn, hemodialysis, malignancy or immunosupression (p> 0.05). The results of the univariate analysis revealed that antibiotic use and parameters most likely to be associated with MRSA bacteremia (obesity, cerebrovascular event, hospitalization history, central/arterial catheter, presence of tracheostomy, invasive/non-invasive mechanical ventilation, use of proton pump inhibitors, H2 receptor blockers, sucralfate, nasogastric or urinary tubes, gastrostomia, total parenteral nutrition, acute organ failure and surgical operation) were found to be statistically higher in the case group (p< 0.05). Median length of hospital stay was also higher in the case group (59 days versus 8 days; p< 0.001). Multivariate regression analysis indicated that obesity (OR= 7.98; p= 0.013), central venous catheterization (OR= 6.65; p= 0.005), nasogastric tube (OR= 16.58; p< 0.001) and use of H2 receptor blockers (OR= 4.41; p= 0.010) were independent risk factors. The number of patient given at least one antibiotic (92 in case group, 51 in control group) was statistically higher than those who were not (48 in case group, 7 in control group) (OR= 14.86; p< 0.001). Use of antibiotics [ampicillin-sulbactam and/or amoxicillin-clavulanate, fluoroquinolones, aminoglycosides, piperacillin-tazobactam (TZP), meropenem (MEM), imipenem (IPM), vancomycin (VAN), cephalosporins and teicoplanin (TEC)] were found to be statistically significantly higher in the case group by univariate analysis (p< 0.05). In multivariate analysis, it was determined that TZP (OR= 6.82; p< 0.001), IPM (OR= 3.97; p= 0.023) and VAN (OR= 8.46; p= 0.001) use were independent risk factors in MRSA bacteremia. The duration of MEM (p= 0.037) and cephalosporin use (p< 0.001) were significantly longer in the case group, however there was no statistically significant difference between the duration of use of other antibiotics (p> 0.05). All MRSA isolates were mecA gene positive (n= 99), the resistance rates for ciprofloxacin, rifampin, gentamicin, tetracyclin, cefoxitin, erythromycin and clindamycin were 95%, 95%, 94%, 96%, 98%, 71% and 36%, respectively. All of the isolates were found to be susceptible to trimethoprim-sulfamethoxazole, VAN, TEC, tigecycline, linezolid and daptomycin. Mortality rates in patients who were infected with MRSA strains exhibiting vancomycin MIC value of ≤ 1.0 µg/ml (n= 49) and with MRSA strains exhibiting MIC > 1.0 µg/ml (n= 50) were 34.6% (17/49) and 60% (30/50), respectively. This difference was found to be statistically significant (p= 0.012). Thus it was concluded that the mortality rate increased in patients infected with MRSA with high (> 1.0 µg/ml) vancomycin MIC value. The results of this study indicated that obesity, presence of central venous catheter and nasogastric tube, and the use of H2 receptor blockers, IPM, TZP and VAN were independent risk factors for MRSA bacteremia. This was the first study showing the relationship between increasing mortality and high vancomycin MIC values in MRSA bacteremia in Turkey.

EXPRESS: Predictive Modeling of Mortality in Carbapenem-Resistant Acinetobacter baumannii Bloodstream Infections Using Machine Learning.

Acinetobacter baumannii, a notable drug-resistant bacterium, often induces severe infections in healthcare settings, prompting a deeper exploration of treatment alternatives due to escalating carbapenem resistance. This study meticulously examined clinical, microbiological, and molecular aspects related to in-hospital mortality in patients with carbapenem-resistant A. baumannii (CRAB) bloodstream infections (BSI). From 292 isolates, 153 cases were scrutinized, reidentified through MALDI-TOF-MS, and evaluated for antimicrobial susceptibility and carbapenemase genes via multiplex PCR. Utilizing supervised machine learning, the study constructed models to predict 14-day and 30-day mortality rates, revealing the Naïve Bayes model's superior specificity (0.75) and area under the curve (AUC; 0.822) for 14-day mortality, and the Random Forest model's impressive recall (0.85) for 30-day mortality. These models delineated 8 and 9 significant features for 14-day and 30-day mortality predictions, respectively, with 'septic shock' as a pivotal variable. Additional variables such as neutropenia with neutropenic days prior to sepsis, mechanical ventilator support, chronic kidney disease, and heart failure were also identified as ranking features. However, empirical antibiotic therapy appropriateness and specific microbiological data had minimal predictive efficacy. This research offers foundational data for assessing mortality risks associated with CRAB BSI and underscores the importance of stringent infection control practices in the wake of the scarcity of new effective antibiotics against resistant strains. The advanced models and insights generated in this study serve as significant resources for managing the repercussions of A. baumannii infections, contributing substantially to the clinical understanding and management of such infections in healthcare environments.

The Use of CHROMID® Colistin R for the Detection of Colistin-Resistant Gram-Negative Bacteria in Positive Blood Cultures.

The aim of this study was to assess the utility of CHROMID® Colistin R for direct detection of colistin-resistant Gram-negative bacteria from positive blood cultures. A total of 390 blood cultures from hospitalised patients containing Gram-negative bacteria were included in this study. These blood cultures were referred to clinical laboratories in the United Kingdom and Türkiye. A further 16 simulated positive blood culture bottles were included that contained a range of colistin-resistant strains as well as susceptible control strains. Fluid from each positive blood culture was diluted 1/200 in saline and 10 µL aliquots cultured onto cystine-lactose-electrolyte-deficient agar and CHROMID® Colistin R. All recovered bacteria were identified, and for Gram-negative bacteria, their minimum inhibitory concentration of colistin was measured using the broth microdilution method. From a total of 443 Gram-negative isolates, 57 colistin-resistant isolates were recovered, of which 53 (93%) grew on CHROMID® Colistin R within 18 h. Of the 377 isolates determined to be colistin-susceptible, only 9 isolates were able to grow, including 6 isolates of Pseudomonas aeruginosa. For positive blood cultures that are shown to contain Gram-negative bacteria, culture on CHROMID® Colistin R is a useful diagnostic tool to detect susceptibility or resistance to colistin within 18 h.

Risk factors for intensive care unit acquired nasal colonization of MRSA and its impact on MRSA infection.

OBJECTIVE: We aimed to determine the risk factors of methicillin-resistant Staphylococcus aureus (MRSA) colonization, and the impact of colonization on MRSA infection to evaluate the necessity of MRSA survey program in intensive care units (ICUs) in Turkey. METHODS: The patients hospitalized in medical and neurosurgical ICUs longer than 24 hr were included into the study. To determine anterior nares MRSA colonization, swabs were taken from each patient in the first 48 hr, and followed by once a week till discharge from ICUs. RESULTS: During the one-year follow-up period, the number of the hospitalized patients who spent more than 24 hr in ICUs was 195 of 372 and 85 of 619 in medical and neurosurgical ICUs, respectively. Totally, 23 out of 280 patients (14 from medical ICU, 9 from neurosurgical ICU) were colonized with MRSA, and 11 out of 23 colonized patients were accepted as ICU-acquired infection. The duration of ICU hospitalization in patients with ICU-acquired MRSA colonization was found to be longer than the noncolonized patients (18 days vs. 8 days, P value < 0.001). The presence of gastrostomy and femoral catheter were determined as risk factors for ICU-acquired MRSA colonization. The percentages of MRSA infection in patients with and without MRSA colonized were 8.6% and 1.1%, respectively (P value: 0.009). CONCLUSION: The presence of gastrostomy and femoral catheter, and the duration of ICU hospitalization were found to be related with ICU-acquired MRSA colonization. Also, MRSA nares colonization increased the rates of both MRSA infection and ICU hospitalization.

Cessation of Rectal Screening for Vancomycin-Resistant Enterococci: Experience from a Tertiary Care Hospital from Türkiye.

OBJECTIVE: Here, we compared the impact of different polices on the epidemiology of Vancomycin-resistant Enterococcus faecium bloodstream infections (VRE-BSIs) in a tertiary care hospital including two hospital buildings (oncology and adult hospitals) in the same campus. MATERIAL AND METHODS: All patients who were hospitalized in high-risk units were screened weekly for VRE colonization via rectal swab between January 2006 and January 2013. After January 2013, VRE screening was only performed in cases of suspicion of VRE outbreak and during point prevalence studies to evaluate the epidemiology of VRE colonization. Contact precautions were in place for all VRE-positive patients. The incidence density rates of hospital-acquired (HA)-VRE-BSIs were compared between two periods. RESULTS: While the rate of VRE colonization was higher in the second period (5% vs. 9.5% (p < 0.01) for the adult hospital, and 6.4% vs. 12% (p = 0.02 for the oncology hospital), there was no increase in the incidence rate HA-VRE BSIs after the cessation of routine rectal screening in either of the hospitals. CONCLUSION: Screening policies should be dynamic and individualized according to the epidemiology of VRE as well as the workforce and cost. Periodical rectal screening of VRE can be discontinued if suspicion of an outbreak can be carefully monitored.

In-vitro activity of fosfomycin against Escherichia coli and Klebsiella pneumoniae bloodstream isolates and frequency of OXA-48, NDM, KPC, VIM, IMP types of carbapenemases in the carbapenem-resistant groups.

The aim of this study was to determine the in-vitro activity of fosfomycin against Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) isolates and the frequency of OXA-48, NDM, KPC, VIM, IMP types of carbapenemases in the carbapenem-resistant (CR) groups. A total of 346 isolates (126 E. coli and 220 K. pneumoniae) from nosocomial bloodstream infections were included. Carbapenem and fosfomycin susceptibility were tested by Etest (bioMerieux, France) and agar dilution methods, respectively and evaluated in accordance with EUCAST criteria. The presence of OXA-48, NDM, KPC, VIM, IMP types of carbapenemases were conducted by using PCR method. Of the total 346 isolates, 185 (41 E. coli, 144 K. pneumoniae) were CR. Fosfomycin susceptibility of E. coli was higher than 95% and was not statistically significant between the CR and carbapenem-susceptible (CS) groups. Fosfomycin susceptibility of CS and CR K. pneumoniae was 90.7% and 69.4%, respectively, and statistically significantly lower in CR group. Of the total 185 CR isolates, 163 (32 E. coli, 131 K. pneumoniae) were producing carbapenemases. OXA-48 was the prominent carbapenemase type produced by E. coli (96.8%) and K. pneumoniae (70.9%). The frequency of NDM and KPC types produced by K. pneumoniae was 20.6% and 15.2%, respectively. Fosfomycin has substantial in-vitro activity against nosocomial CS and CR E. coli and CS K. pneumoniae bloodstream isolates. However, due to the risk of emerging resistance with fosfomycin monotherapy, combination therapy should be considered to obtain the possible additive or synergistic activity. Emerging fosfomycin resistance of CR K. pneumoniae isolates is alarming and OXA-48 is still the prominent carbapenemase type in Turkey.

The impact of COVID-19 pandemic on nosocomial multidrug-resistant bacterial bloodstream infections and antibiotic consumption in a tertiary care hospital.

We investigated the change in the epidemiology of nosocomial bloodstream infections (BSIs) caused by multidrug-resistant bacteria during Coronavirus Disease (COVID-19) and antibiotic consumption rates at a pandemic hospital and at the Oncology Hospital which operated as COVID-19-free on the same university campus. Significant increases in the infection density rate (IDRs) of BSIs caused by carbapenem-resistant Acinetobacter baumannii (CRAB) and ampicillin-resistant Enterococcus faecium (ARE) were detected at the pandemic hospital, whereas carbapenem-resistant Klebsiella pneumoniae BSIs were increased at the non-pandemic Oncology Hospital. Pulsed field gel electrophoresis showed a polyclonal outbreak of CRAB in COVID-19 intensive care units. Antibiotic consumption rates were increased for almost all antibiotics, and was most significant for meropenem at both of the hospitals. Increased IDRs of CRAB and ARE BSIs as well as an increased consumption rate of broad-spectrum antibiotics emphasize the importance of a multimodal infection prevention strategy combined with an active antibiotic stewardship program.

[Frequency of curable sexually transmitted infections among registered female sex-workers in Ankara City]. / Ankara ilinde kayitli seks calisani kadinlarda iyilestirilebilir cinsel yolla bulasan enfeksiyonlarin sikligi.

Sex-workers are considered as the high-risk population for sexually transmitted infections (STIs). Early diagnosis and treatment of curable STIs in this high-risk group have crucial importance in STI control and prevention of complications and transmission of infection. In this study, 146 registered female sex-workers in Ankara city were screened with rapid diagnostic tests (RDT) for causative agents of curable STIs such as, Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis and Treponema pallidum. To identify gonorrhoea, Gram stained endocervical smears were examined microscopically for the presence of gram-negative intracellular diplococci. For the diagnosis of chlamydial infection, an optic immunoassay (OIA) (Chlamydia OIA, Biostar, USA) as a RDT was performed by using endocervical specimens. For the detection of T. vaginalis, direct smears of vaginal swabs were examined for the presence of motile trophozoites first directly and after being cultured in Diamond's media for 24-48 hours of incubation. Syphilis was screened in the serum specimens by RPR (Omega, UK) test. There was no positive test results for gonorrhoea and syphilis however, the frequency of C. trachomatis and T. vaginalis in the study population was 1.4% and 0.7%, respectively. To provide comprehensive policies and optimal control strategies, a reliable source of data about the frequency and spectrum of STIs among high-risk populations and optimized effective screening programmes are required.

[Epidemiological and molecular characteristics of hospital-acquired methicillin-resistant Staphylococcus aureus strains isolated in Hacettepe University Adult Hospital in 2004-2005]. / Hacettepe Üniversitesi Eriskin Hastanesinde 2004-2005 yillarinda izole edilen hastane kaynakli metisiline dirençli Staphylococcus aureus suslarinin epidemiyolojik ve moleküler özellikleri.

The aim of this study was to determine the epidemiological and molecular characteristics of hospital-acquired (HA)-methicillin-resistant Staphylococcus aureus (MRSA) isolates by investigating the distribution of clinical samples according to the hospital wards, antibiotic susceptibility patterns, staphylococcal chromosome cassette mec (SCCmec) types and the presence of Panton-Valentine Leukocidin (PVL) genes. A total of 110 MRSA isolates obtained from various clinical samples of inpatients at Hacettepe University Adult Hospital between January 2004 and December 2005 were included in the study. The identification of the isolates was done by BD Sceptor automated system (Becton Dickinson, USA). The mecA gene, SCCmec types and PVL genes were detected by polymerase chain reaction (PCR). Pulsed field gel electrophoresis (PFGE) was performed to examine the clonal relatedness. The susceptibility testing was performed for some antibiotics by E-test (AB Biodisk, Sweden) and for the others by disk diffusion methods according to the Clinical and Laboratory Standards Institute (CLSI) recommendations. The clinical samples (35 blood, 37 pus, 23 deep tracheal aspiration, 5 catheter, and 10 other samples) that yielded the MRSA strains were isolated from patients (71.5%) at intensive care units and surgical wards. All the isolates were positive for mecA gene. Of the isolates, 68 (61.8%) were harboring SCCmec type III, 38 (34.5%) SCCmec variant IIIB, and 3 (2.7%) SCCmec type IV. One isolate which was mecA gene positive could not be classified in any of the SCCmec types. PVL was positive in 14 (12.7%) of the isolates. All MRSA strains were susceptible to tigecycline, linezolid, vancomycin and teicoplanin; however, exhibited high rates (> 90%) of resistance to gentamicin, ciprofloxacin and rifampin. Susceptibility rates to trimethoprim/sulfamethoxazole was 90%, clindamycin 53% and erythromycin 32%. Eight pulsotypes were distinguished on the basis of PFGE (A, B, C, D, K, L, N, O). Of the total isolates, 92.7% belonged to pulsotype A. HA-MRSA strains predominantly isolated from pus and blood samples of inpatients at intensive care units and surgical wards in our hospital were multi-resistant. Majority of these isolates were SCCmec III, or variant IIIB type. Although PVL is known as a common virulence factor of community-acquired MRSA, HA-MRSA isolates in our center have a considerable rate of PVL positivity pointing out the importance of surveillance of the changing epidemiology of MRSA.

Emergence of colistin and carbapenem-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii (CCR-Acb) complex in a neurological intensive care unit followed by successful control of the outbreak.

BACKGROUND: Colistin and carbapenem-resistant Acinetobacter calcoaceticus- Acinetobacter baumannii complex (CCR-Acb complex) was isolated from two consecutive patients in the neurological intensive care unit (NICU). An urgent reaction to this desperate situation was required. PATIENTS AND METHODS: Screening cultures were taken from the other patients sharing the NICU with index patients and repeated periodically. NICU was closed for new admissions. Infection control precautions (ICP) such as hand hygiene, cohorting patients colonized with CCR-Acb complex, cohorting the staff caring for these patients, daily bathing with chlorhexidine gluconate impregnated clothes, using gowns when contacting with patients and patient care area, and sodium hypochlorite tablets for environmental cleaning were enforced. RESULTS: Screening cultures revealed carbapenem-resistant Acb complex in 12 out of 32 patients and 8 of them were colonized with CCR-Acb complex. NICU was opened for new admissions one month later. No further new cases with CCR-Acb complex were detected by screening cultures after 6 weeks with enforcement of ICP. Moreover, the rate of nosocomial infections caused by other multi-drug resistant Gram-negative bacilli (MDR-GNB) decreased significantly when rates before and after closing the NICU were compared. CONCLUSION: ICP were effective not only to limit the spread of CCR-Acb complex but also decreased the incidence of other MDR-GNB infections when applied adequately.

Antibiotic resistance surveillance over a 4-year period (2000-2003) in Turkey: results of the MYSTIC Program.

The Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program is a global study that provides antimicrobial susceptibility data in centers prescribing meropenem. The activity of meropenem and 7 broad-spectrum antimicrobials have been examined against 5208 bacterial isolates from 9 Turkish centers between 2000 and 2003. Cumulative susceptibility rates against all species of Enterobacteriaceae combined were ranked as follows: meropenem (99.3%), imipenem (97.6%), cefepime (80.0%), piperacillin-tazobactam (73.6%), ceftazidime (70.3%), ciprofloxacin (70.1%), cefotaxime (66.9%), and tobramycin (67.2%). The production of extended-spectrum beta-lactamases (ESBLs) was detected in 48.7% of Klebsiella pneumoniae and in 19.5% of Escherichia coli isolates. Of ESBL producing K. pneumoniae isolates, 75.7% were resistant to tobramycin, 40.3% to ciprofloxacin, and 48.3% to piperacillin-tazobactam. Only piperacillin/tazobactam and carbapenems were active against more than 50% of Pseudomonas aeruginosa at the National Committee for Clinical Laboratory Standards-susceptible breakpoint, and the carbapenems were the most active compounds against Acinetobacter spp. These data confirm the continued potency of meropenem against Enterobacteriaceae in units where it is actively being prescribed.

[Prevalence of extended-spectrum beta-lactamases in nosocomial Escherichia coli and Klebsiella spp. strains isolated from blood cultures]. / Hastane enfeksiyonu etkeni olarak kan kültürlerinden izole edilen Escherichia coli ve Klebsiella spp. suslarinda genislemis spektrumlu beta-laktamaz prevalansi.

The aim of this study was to determine the prevalence of extended-spectrum beta-lactamases (ESBLs) in nosocomial bacteremia isolates of Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca at Hacettepe University Adult Hospital in Ankara, Turkey. A total of 344 blood culture isolates of E. coli (n=244), K. pneumoniae (n=86) and K. oxytoca (n=34) were included in the study from January 2003 to November 2005. Only one isolate from one patient was tested in the study. The isolates with ceftazidime and/or cefotaxime MIC values > or =1 microg/ml were tested by ceftazidime-ceftazidime/clavulanic acid and cefotaxime-cefotaxime/clavulanic acid Etest (AB Biodisk Solna, Sweden) strips and evaluated as ESBL positive if the ratio was > or =8. Of the isolates, 33% (74/224) of E. coli, 31.4% (27/86) of K. pneumoniae and 47% (16/34) of K. oxytoca were detected as ESBL producers by any kind of two strips. However, 5.4% (4/74) of E. coli, 3.7% (1/27) of K. pneumoniae and 43.1% (7/16) of K. oxytoca ESBL-producing isolates could be detected only by cefotaxime-cefotaxime/clavulanic acid strips. It is important to use cefotaxime-cefotaxime/clavulanic acid as well as ceftazidime-ceftazidime/clavulanic acid ratio for detection of ESBL types that preferentially hydrolyze cefotaxime. Since prevalence of ESBL production is high in nosocomial E. coli and Klebsiella spp. isolates in our hospital, surveillance of antibiotic susceptibility patterns is important for the empirical treatment of bacteremic patients.

[The frequency of PER-1 type extended spectrum beta-lactamases in nosocomial isolates of Pseudomonas aeruginosa]. / Hastane kaynakli Pseudomonas aeruginosa izolatlarinda PER-1 türü genislemis spektrumlu beta-laktamaz enzimlerinin sikligi.

The aim of this study was to determine the frequency of PER-1 type extended-spectrum beta-lactamase (ESBL) in nosocomial Pseudomonas aeruginosa strains isolated in Hacettepe University Adult Hospital. Sixty-seven non-duplicate P. aeruginosa isolates from patients with nosocomial infections between January 2002 and December 2004 were included in the study. The isolates were identified at species-level by Sceptor (Becton Dickinson, USA) system, and all the strains were stored at -80 degrees C until further testing. Polymerase chain reaction (PCR) was performed for the detection of (bla)PER-1 genes, and PFGE analysis was used to investigate their genetic relatedness. The antimicrobial susceptibilities of the PER-1 positive isolates were determined by Etest (AB Biodisk, Solna, Sweden) method. According to the results of PCR, 22.7% (15/67) of the isolates were positive for PER-1 enzyme. Those 15 (bla)PER-1 positive isolates showed eight different PFGE patterns, indicating the presence of multiple clones. Of the PER-1 positive P. aeruginosa isolates, nine were resistant to imipenem/meropenem, and 11 were resistant to piperacillin-tazobactam and tobramycin. The epidemiological investigation of multidrug resistant P. aeruginosa should give important clues for the initial empirical therapy, especially in certain geographic locations where ESBL-producing P. aeruginosa strains seemed to be highly prevalent.