Gram-Negative Bloodstream Infections in Healthcare: The Relationship Between Antibiotic Resistance, Mortality, and Novel Serological Biomarker.

BACKGROUND: Bloodstream infections caused by Gram-negative bacteria are highly mortal. In this study, we aimed to investigate the relationship between antimicrobial resistance profile and novel serological biomarkers and mortality in bloodstream infections (BSIs) caused by Gram-negative bacteria in intensive care units (ICUs). METHODS: 366 Patients diagnosed with healthcare-associated Gram-negative bloodstream infection in the ICUs of our hospital between February 2015 and December 2021 were included in the study. Demographic variables (age, gender, comorbidities), causative microorganisms and antimicrobial susceptibilities, time to first positive blood culture after hospitalization, length of stay in hospital, surgical procedures, laboratory data (hemograms, C-reactive protein (CRP) levels, albumin), and survival data were collected. Novel serological biomarkers were calculated. RESULTS: Mortality in Gram-negative bloodstream infection was found to be associated with age and novel serological biomarkers, but not with carbapenems and colistin minimum inhibitory concentration (MIC) values. Mortality rates increased with age (p˂0.001). Patients who died had higher C-reactive protein/albumin ratio (CAR) (p<0.001) and neutrophil/lymphocyte ratio (NLR) (p=0.009) and lower prognostic nutritional index (PNI) (p<0.001). CONCLUSION: The study emphasizes that resistance to colistin and carbapenems is not associated with mortality in BSIs caused by Gram-negative bacteria. Novel serological biomarkers may be useful in predicting mortality. These results support the need for further studies to elucidate the true impact of infections caused by resistant bacteria.

Comparison of the Distribution of Healthcare-Associated Infections and Causative Agents Between Intensive Care Units and Other Clinics.

OBJECTIVE: To compare the trends in the distribution of healthcare associated infectious (HAIs) and causative agents in intensive care units (ICUs) and other clinics. STUDY DESIGN: Descriptive study. Place and Duration of the Study: Department of Infectious Diseases and Clinical Microbiology, Health Sciences University, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkiye, from 2015 to 2022. METHODOLOGY: The study included patients who were diagnosed with HAIs and admitted to both the ICUs and the clinics. The data of HAIs identified between 2015-2022 were accessed and analysed retrospectively from the surveillance records of the IPC committee between 28.05.2023-07.08.2023. RESULTS: There was a decreasing trend observed in both ICU and clinics regarding the ratio of patients developing HAIs and the overall HAI rate (all p-values <0.001). These two measures were found to be significantly lower in the years 2019-2022 compared to the years 2015-2018. Over the years, particularly after 2020, a significant increasing trend in carbapenem resistance was observed in E. coli, K. pneumoniae, and P. aeruginosa (p=0.009, p<0.001, and p<0.001, respectively). The ratio of patients developing HAIs in the ICUs was higher than in the clinics (p<0.001). There was an increasing trend in the ratio of pneumonia and bloodstream infection (BSI) in ICUs. CONCLUSION: The increasing ratio of BSI and pneumonia in ICUs highlighted the need to review infection control bundles. Carbapenem resistance has been increasing over the years, suggesting that antimicrobial description and consumption practices should be re-evaluated, especially in the context of the COVID-19 pandemic. KEY WORDS: Intensive Care Unit, Healthcare-Associated Infections, Surveillance, Infection prevention and control, Antibiotic resistance.

Community-acquired antimicrobial resistance among Syrian refugees and the local population in Türkiye.

BACKGROUND: The long-standing antimicrobial resistance (AMR) pandemic has proven difficult to resolve and is becoming more complex, especially in the context of increasing forced migration, with little evidence around patterns of AMR in migrant communities. This study aimed to determine the frequency in the carriage of common types of antimicrobial-resistant bacteria between Syrian refugees and the local communities in Türkiye: extended-spectrum ß-lactamase (ESBL), methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). METHODS: We collected nasal swabs and stool samples from the study participants, the local community members, and refugees, between September 2020 and March 2021. We screened clinical samples for the presence of ESBL, MRSA and VRE. Antimicrobial-resistant bacterial isolates were tested by phenotypic analysis to determine the AMR status. RESULTS: The study included a total of 3960 participants: 1453 individuals in the local community (36.2%) and 2525 Syrian refugees (63.8%). Overall, a significantly greater proportion of refugees (6.7%) carried MRSA compared to the local community (3.2%) (P < 0.001). The ESBL-positivity rate was 17.9% in Syrian refugees and 14.3% in the local community (P = 0.041). Carbapenemase activity was detected in three isolates from Syrian refugees. No VRE was detected in Syrian refugees or the local community. CONCLUSIONS: This large, community-based study on the frequency and the distribution of AMR among Syrian refugees and the local population is the first study in Türkiye.

ESBL production and carbapenem resistance increased the secondary bloodstream infection rates in intensive care units in Turkey, 2014-2019.

Aim: Secondary bloodstream infections (SBSIs) are caused by another infection and differ from primary bloodstream infections (PBSIs) in terms of prevention and treatment strategies. The aim of this study was to determine the risk factors for bloodstream infections which were secondary to the most common healthcare-associated infections caused by the most common microorganisms in intensive care units (ICUs) and to examine whether extended-spectrum beta lactamase (ESBL) production and carbapenem resistance is related to the higher risk or not. Methods: The study population consisted of patients in ICUs with ventilator-associated pneumonia (VAP), ventilator-associated event (VAE) or catheter-associated urinary tract infection (CAUTI) caused by E. coli, K. pneumoniae, P. aeruginosa or A. baumannii between 2014 and 2019. The data were obtained through the National Healthcare-associated Infections Surveillance Network. Multivariate logistic regression analysis was performed separately for VAP/VAE and CAUTI to determine the risk factors for the development of SBSI. Results: Microorganism, ICU type, bed capasity and carbapenem resistance were found to be risk factors for SBSI for both types of infection. For VAPs/VAEs, female gender and hospital type were also identified as risk factors. The highest risk was in K.pneumoniae and in emergency ICUs. Among the hospitals, the highest risk in VAPs/VAEs was found in government education and research hospitals. ESBL production for K. pneumoniae and E. coli increased the risk in patients with VAP/VAE; however, it did not increase in patients with CAUTI. Discussion: By using the risk factors, it may be possible to recognize SBSIs earlier, especially in patients with CAUTIs or VAPs/VAEs caused by carbapenem-resistant or ESBL-producing K. pneumoniae.

Discrepancy between colistin and polymyxin B susceptibility results among Escherichia coli and Klebsiella pneumoniae clinical isolates.

The selection of therapeutic agent to be used for the treatment of multidrug-resistant bacteria is a major concern. Polymyxin B use has been commenced in Turkey, although its clinical breakpoint is not listed in the EUCAST. This study aimed to determine the correlation between the MIC values of polymyxin B and colistin. A total of 505 isolates, including 122 isolates of Escherichia coli and 383 isolates of Klebsiella pneumoniae were included in the present study. All the isolates were assessed for colistin and polymyxin B using the broth microdilution method. The categorical agreement in the E. coli isolates was 98.4%, and the rate of very major error was 33.3%. The categorical agreement in the K. pneumoniae isolates was 99.5%, the rate of major error was 0.36%, and the rate of very major error was 0.98%. In the evaluation of the essential agreement, 1.6% error in E. coli and 2.3% error in K. pneumoniae were observed. It was concluded that polymyxin B should never be used in the treatment of the isolates reported as colistin-resistant, and if the MIC values are above 4 mg/L in E. coli and K. pneumoniae. Our results indicate importance of reporting both polymyxin B and colistin susceptibility results of clinical isolates.

[The Epidemiology of Carbapenemases in Escherichia coli and Klebsiella pneumoniae Isolated in 2019 in Turkey]. / Türkiye'de 2019 Yili Içinde Izole Edilen Escherichia coli ve Klebsiella pneumoniae Izolatlarinda Karbapenemaz Epidemiyolojisi.

Antibiotic resistance is one of the most important public health problem and one of the most critical steps in preventing resistance is the monitorization of the resistance. Local, regional and global monitoring enables the spread of antibiotic resistance to be understood more clearly. In this study, it was aimed to evaluate the results of the pilot study for the establishment of molecular-based carbapenem surveillance system in Escherichia coli and Klebsiella pneumoniae isolates and to investigate the carbapenemase epidemiology in Turkey. Hospitals (n= 28) from 26 different statistical level II regions from Turkey were included in the study. The hospitals participated in the study submitted ten carbapenem susceptible and ten carbapenem resistant E.coli and K.pneumoniae isolates to our laboratory that were isolated in two different periiods of six-month either between 1 March-31 August or 1 April-30 September 2019. A total of 509 isolates were collected from 26 of the 28 participating hospitals in the study. Isolates were identified by matrix assisted laser desorptionization-time of flight mass spectrophotometry (MALDI TOF MS) (Bruker Daltonics, Germany) method and antibiotic susceptibility tests for imipenem, meropenem and colistin were studied by broth microdilution. Moreover, susceptibilities to amikacin, amoxicillin-clavulanic acid, ampicillin, aztreonam, cefepime, cefotaxime, ceftazidime, ciprofloxacin, ertapenem, gentamicin, piperacillin-tazobactam, tobramycin and trimethoprim-sulfamethoxazole were determined by disc diffusion method. The resistance genes were investigated in isolates which were found to be phenotypically resistant to carbapenem and colistin, in house method was used to investigate carbapenemase genes and a commercial colistin resistant real-time PCR kit (Biospeedy, Turkey) was used for colistin resistance genes. In total, 493 of the 509 isolates collected from hospitals were identified as E.coli (25.7%, n= 127) and K.pneumoniae (74.3%, n= 366) and included in the study. It was determined that 31% of the isolates evaluated were from community-acquired infections and 69% were either from healthcare-associated infections or from colonization sites. Among the tested isolates, 248 (50.3%) were susceptible to carbapenems and 245 (49.7%) were resistant. The types of carbapenemases in carbapenemase-producing were OXA-48 (52.2%), KPC (16.1%), NDM-1 (15%), OXA-48 + NDM-1 (12.6%), KPC + NDM-1 (2.8%) and VIM (0.5%) and OXA-48+VIM (0.5%). Resistance to colistin was detected in 23.3% of the isolates but mcr1-8 genes were not detected. It was found that all colistin resistant isolates are resistant to at least one of the carbapenems. The importance of a molecular-based antimicrobial resistance surveillance system in our country was demonstrated with this pilot study. It is thought that continuous monitoring of these epidemiological features will contribute to the management of infections due to carbapenemase-producing organisms.

National Infection Control Program in Turkey: The healthcare associated infection rate experiences over 10 years.

BACKGROUND: The prevalence of healthcare associated infection (HAI) is generally higher in countries with limited resources than developed countries. To address the high prevalence of HAI, Turkish Ministry of Health introduced a national infection control program in 2005. METHODS: Device associated (DA)-HAIs routinely surveyed included ventilator associated events, urinary catheter associated urinary tract infection and central line associated blood stream infection. Rates in DA-HAI were examined from 2008 to 2017 by type of hospitals, bed capacity, and geographic location of hospitals. RESULTS: All DA-HAIs declined significantly from 2008 to 2017 nationally for ventilator associated events from 16.69 to 4.86 per 1,000 device days (IRR = 0.29, P < .0001), catheter associated urinary tract infection from 4.98 to 1.59 per 1,000 catheter days (IRR = 0.31, P < .0001) and central line associated blood stream infection from 5.65 to 2.82 per 1,000 catheter days (IRR = 0.47, P < .0001). The rates for DA-HAIs declined significantly in hospitals with ≥200 beds and <200 bed capacity and in all 4 type of hospitals. By 2017 all DA-HAI had significantly improved across all regions. CONCLUSIONS: The introduction of a new national surveillance system supported by a national infection control program has significantly reduced 3 major DA-HAIs that are associated with risk of treatment failure and death. The next critical step in sustaining this crucial improvement will require timely feedback to hospitals using technology and continued buy-in from clinicians for their commitment to safety associated with DA-HAIs using aspirational DA-HAI rates.

[Direct Identification of Microorganisms from Positive Blood Cultures by MALDI-TOF MS Using an in-House Tween® 80 Method: Experimental and Clinical Study]. / "In-House" Tween® 80 Yöntemi ile Pozitif Kan Kültürlerinden Mikroorganizmalarin MALDI-TOF MS Yöntemi ile Dogrudan Tanimlanmasi: Deneysel ve Klinik Çalisma.

It has been reported that direct identification from blood culture bottles with positive signals and reporting the results to the clinics earlier has positive effects on mortality and morbidity. Extraction methods especially using detergents are used for the direct identification from the bottles which give positive signal. For this purpose, in-house methods developed based on the usage of saponin are widely available in the literature. In this study, it was aimed to develop a simple, easy-to-apply and reliable protocol for identifying the agent directly from the blood culture bottle that gives positive signal with the use of detergent Tween® 80, and to study the obtained protocol in clinical samples in a routine microbiology laboratory and to evaluate the results. The study was carried out in two stages, the experimental stage where the method was developed and the clinical stage where the method was applied. In the experimental stage, blood culture bottles were created with standard strains and isolates previously diagnosed with the 16S rRNA method. 10% solution of Tween® 80 was prepared with distilled water. 1 ml sample was transferred from the bottle that gave positive signal to the microcentrifuge tube, 100 µl of 10% solution of Tween® 80 was added, vortexed for 10 seconds and then incubated for 5 minutes at room temperature. The tubes were centrifuged for 5 min at 14.000 rpm, the supernatant was discarded and the pellet was washed with 1 ml of distilled water and centrifuged at 14.000 rpm for 5 minutes in three times. Samples taken from the pellets were rubbed on the slide and dried on air. Firstly, 1 µl of 70% formic acid, then 1 µl, of matrix solution was added and it was used after drying. In the second stage of the study, the method was applied to the 502 vials giving positive signal in the Microbiology Laboratory of Ankara University Faculty of Medicine Ibni Sina Hospital between 17 April 2018-31 August 2018 and the results were compared with the subculture results. The results obtained at the end of extraction in the experimental stage were compared with the subculture results and no statistical difference was found. In 383 (82.9%) bottles among 462 (92.1%) bottles with monomicrobial positive cultures, compatible results with the subculture results were obtained. Of the microorganisms correctly identified, 350 (91.3%) were bacteria and 33 (8.7%) were fungi. On the other hand, 216 (56.4%) of the bacteria were gram positive and 134 (34.9%) of them were gram negative bacteria. At least one microorganism was correctly identified in 19 (47.5%) of 40 (7.9%) bottles with polymicrobial blood cultures. Their distribution was gram negative (n= 10) and gram positive (n= 8) and yeast (n= 1). No microorganisms were identified in six bottles with polymicrobial cultures. According to the results, we believe that this in-house method developed using Tween® 80 will be a routinely applicable method for blood culture bottles that give positive signal in microbiology laboratories and it will contribute to the early diagnosis.

[Seroprevalence of pertussis toxin antibody in Manisa province of Turkey, after six years implementation of acellular pertussis vaccine]. / Hücre içermeyen bogmaca asi uygulamasinin altinci yilinda Türkiye'nin Manisa ilindeki pertussis toksin antikoru seroprevalansi.

Vaccination is the most effective way of preventing pertussis disease. Turkey commenced a routine infant immunization program using whole cell (wP) pertussis vaccine in 1968. Immunization accelerated in 1985 after participation of Turkey in the Expanded Programme on Immunization initiated by the World Health Organization. Acellular vaccine (aP) replaced wP in 2008 and a booster was added to age 6 in 2010. The immunization programme was successful in reducing the morbidity rate from 20.58 per 100.000 in 1970 to the lowest level of 0.01 per 100.000 in 2009. However, reduction of vaccine-induced protection and reduced natural boosting of circulating Bordetella pertussis are likely to increase the susceptibility of the population. As a result, morbidity rate increased from 0.09 per 100.000 to 0.41 per 100.000 in 2015 compared to the previous year. The aim of this epidemiological study was to determine the seroprevalence of pertussis toxin (PT) antibodies among healthy people and its association with various social determinants in Manisa province in Turkey, 6 years after aP replaced wP vaccine. The study was conducted as a cross-sectional study with a sample of 1250 people that was randomly selected from the over 2 years of age population in Manisa in 2014. Seroprevalence of PT antibody was determined as the dependent variable of the study. Independent variables of the study were; gender, age, migration in the last 5 years, occupational class, perceived income, house ownership, number of people per room, annually per capita equivalent income. The presence of anti-PT IgG was detected by quantitatively using a commercially available ELISA kit. The antibody levels were categorized into groups according to pertussis infection or vaccination immune response status. The groups consisted of undetectable (< 5 IU/ml), mid-range (5-< 62.5 IU/ml: more than one year previously), high (62.5-< 125: with in 12 months) and very high (≥ 125 IU/ml: with in 6 months) antibody levels. The test results with ≥ 5 IU/ml were defined as seropositive. Level > 100 IU/ml detected among adolescent and adult participants indicated acute or recently recovered pertussis infection. Chi-square test was used to evaluate association between social determinants and pertussis seropositivity. The seroprevalence of the whole study population was 58.1% (95% CI 55.32-60.79) and no association was found with any of the social determinants. The highest seroprevalence was found among 2-9 age group (68.3%) followed by 70-79 age group (63.5%). The lowest seroprevalence was found among 20-29 age group (50.9%) followed by 10-19 age group (51.6%). When seropositivity levels according to ages were compared, it was found that there was a decrease one year after the first vaccination at 2nd, 4th and 6th months and the booster at the 6th year, with a lowest rate (19%) in 11 year-old. The highest seropositivity (77.3%) with a level of >100 IU/ml (13.6%) were detected at age 15 among all adolescent and adult participants. Adding an adolescent booster to immunization schedule and recommendation of vaccine to elderly people should be considered to reduce the incidence of pertussis disease in Turkey.

Seroprevalence and social determinants of varicella in Turkey.

BACKGROUND: In Turkey, varicella vaccine was introduced into routine childhood immunization in 2013, with a single dose administered to children aged 12 months. However, there is limited information on the morbidity (incidence and seroprevalence), mortality and burden of disease of varicella in the overall Turkish population. AIM: To determine varicella seroprevalence and its social determinants in Manisa Province, Turkey in children aged > 2 years before single-dose varicella vaccination was introduced in 2013. METHODS: The presence of anti varicella-zoster virus IgG antibodies was determined using enzyme-linked immunosorbent assay in serum samples collected from 1250 participants. RESULTS: The overall seroprevalence was 92.8% and the seroprevalence was > 90% among all age groups except 2-9 years (55.7%). Seroprevalence was significantly associated with family size, annual per capita equivalent income, number of people per room and education level. After adjusting by age, only education level remained significantly associated with seroprevalence, reflecting the early age effect. CONCLUSION: High seroprevalance depends on natural exposure to the infectious agent itself and is not associated with social determinants. High vaccine coverage should be maintained for effective varicella control and switching to a 2-dose schedule may also be considered to reduce the number and size of outbreaks in the Turkish population.

Seasonal Influenza Vaccine Effectiveness in Preventing Laboratory Confirmed Influenza in 2014-2015 Season in Turkey: A Test-Negative Case Control Study.

BACKGROUND: Influenza has an important public health impact worldwide with its considerable annual morbidity among persons with or without risk factors and its serious complications among persons in high-risk groups. The seasonal influenza vaccine is essential for preventing the burden of influenza in a population. Since the vaccine is reformulated each season according to the virus serotypes in circulation, its effectiveness can vary from season to season. Vaccine effectiveness is defined as the relative risk reduction in vaccinated individuals in observational studies. AIMS: To calculate influenza vaccine effectiveness in preventing laboratory-confirmed influenza in the Turkish population for the first time using the national sentinel surveillance data in the 2014-2015 influenza season. STUDY DESIGN: Test-negative case-control study. METHODS: We compared vaccination odds of influenza positive cases to influenza negative controls in the national influenza surveillance in Turkey to estimate influenza vaccine effectiveness. RESULTS: The influenza vaccine effectiveness against influenza A (H1N1) (68.4%, 95% CI: -2.9 to 90.3) and B (44.6%, 95% CI: -27.9 to 66.6) were moderate, and the influenza vaccine effectiveness against influenza A (H3N2) (75.0%, 95% CI: -86.1 to 96.7) was relatively high; all had low precision given the low vaccination coverage. Overall, the influenza vaccination coverage rate was 4.2% (95% CI: 3.5 to 5.0), which is not sufficient to control the burden of influenza. CONCLUSION: In Turkey, national surveillance for influenza should be strengthened and utilised annually for the assessment of influenza vaccine effectiveness with more precision. Annual influenza vaccine effectiveness in Turkey should continue to be monitored as part of the national sentinel influenza surveillance.

Prevalence and associated factors of thrombocytopenia among human immunodeficiency virus-infected patients at a tertiary care hospital in Izmir, Turkey.

BACKGROUND/AIM: The aim of this study was to determine the prevalence and associated factors of thrombocytopenia in human immunodeficiency virus (HIV)-infected patients. MATERIALS AND METHODS: A cross-sectional study was conducted in a tertiary care hospital in Izmir, Turkey. All HIV-infected patients admitted to the Department of Infectious Diseases and Clinical Microbiology between 2006 and 2011 were recruited. Patients with thrombocytopenia at any time point were defined as the case group and the remaining patients were defined as the control group. RESULTS: The frequency of thrombocytopenia was 35.8%. Thrombocytopenia was more frequent in patients with acquired immune deficiency syndrome (AIDS) than in patients without AIDS (P < 0.05) and in antiretroviral-naive patients than in patients on combination antiretroviral therapy (cART) or those who had ever used cART in the past (P < 0.05). Additionally, rates of tuberculosis infection, prophylactic use of trimethoprim-sulfamethoxazole (TMP/SMX), and being anti-HCV seropositive at any time point were higher in patients with thrombocytopenia than in the control group (P < 0.05), and the case group had lower CD4+ T lymphocytes at first admission (P < 0.05). CONCLUSION: The main finding was the clear association between thrombocytopenia and advanced and uncontrolled HIV infection. Tuberculosis and HCV coinfections were also identified as associated factors for thrombocytopenia.