Bloodstream infections in intensive care unit patients: distribution and antibiotic resistance of bacteria

Bloodstream infections in pediatric hematology/oncology patients: a single-center study in Wuhan

Bloodstream infections (BSIs) are a critical concern in pediatric onco-hematological patients undergoing chemotherapy or hematopoietic stem cell transplantation (HSCT), leading to a major impact on morbidity, long-term hospitalization, and mortality. We retrospectively analyzed 202 BSIs in 145 patients, consisting of 128 with hematological malignancies, one with a solid tumor, and 16 with non-malignant hematological diseases. We collected data on patient demographics, clinical characteristics, pathogen distribution, and antimicrobial pathogen susceptibility. Gram-positive infections were the most frequent at (58.4%), followed by gram-negative (41%), and fungal infections (0.5%). Particularly, the majority of these infections occurred during the induction phase of chemotherapy, where 94 (46.5%) BSI episodes were recorded, predominantly in neutropenic patients (88.3%). The consolidation phase experienced lower BSIs (11.8%); among these patients (54.1%) were non-neutropenic. BSIs observed in (23.7%) of patients in the maintenance phase, with a higher proportion (66.6%) being neutropenic. Among the 7 patients who underwent HSCT, BSIs occurred in (4.9%) cases, mainly (70%) due to neutropenia. The most prevalent pathogens were Staphylococcus epidermidis (19.8%), Staphylococcus hominis (16.3%), and Escherichia coli (8.4%). The study highlights the critical need for vigilant monitoring and customized infection management strategies to enhance patient outcomes across chemotherapy phases and HSCT.

Monitoring and controlling bacteria in cleanrooms of pharmaceutical plant model: an in vitro study

This work aims to screen the major species of bacteria distributed in the filling area in one of the new pharmaceutical facilities in the 6th of October city in Egypt and their phylogenic relationship. One hundred percent of collected Gram-positive and Gram-negative isolates of bacteria were sensitive to Levofloxacin. There were five Gram-positive multidrug-resistant (MDR) bacterial isolates and one Gram-negative (MDR) bacterial isolate (three (from personnel), two (from surface), and one (from air)). The five Gram-positive MDR bacterial isolates were resistant to Tobramycin, Gentamicin, Piperacillin, Cefaclor, and Amikacin while the one Gram-negative MDR bacterial isolate was resistant to Ceftazidime, Cefotaxime, Tobramycin, Gentamicin, Piperacillin, Cefoperazone/Sulbactam, Ofloxacin, and Polymixin b. The existence of multidrug-resistant bacteria inside cleanrooms of pharmaceutical plants signifies a life-threatening danger on human through generating contaminated drugs and/or vaccines that undoubtedly harm the consumer's healthiness. The technique of 16SrRNA gene sequencing was used to identify multidrug-resistant bacterial isolates. All tested disinfectants were bactericidal except Dettol that was found to be a bacteriostatic agent and had an anti-biofilm effect. Clorox was the most potent disinfectant that had the least MIC and MBC of 0.0002% and 0.0004%, respectively. Ethanol and Klericide were excellent sanitizing agents. The strongest biofilm formed by Staphylococcus gallinarum strain MN1812 was disrupted by Clorox with a concentration of 0.000098%. Only Dettol with a concentration of 6.3% achieved the highest disruption for the biofilm of Staphylococcus gallinarum strain NM2009. Staphylococcus gallinarum strain MN1812 followed by Bacillus amyloliquefaciens showed the highest adhesion and invasion efficiencies to Caco-cells among the investigated bacterial strains. Klericide and Dettol mixture showed more anti adhesion and invasion effects against Staphylococcus gallinarum strain NM2009 and strain MN1812 and Pseudomonas putida compared to using Klericide alone. Ethanol and Klericide had the least contact time (30 s) against most of the tested bacteria.

Precision medicine and patient outcomes in intensive care unit: Culture sensitivity, antibiotics, and APACHE score IV

BACKGROUND

In the intensive care unit (ICU), complex medical conditions require specialized care; the threat of antibiotic resistance is significant due to frequent antibiotic use. This study investigates the pivotal role of culture sensitivity testing in shaping antibiotic prescription practices and patient outcomes in ICUs.

MATERIALS AND METHODS

By using a prospective observational-analytical design, medical data from 640 patients at a Karachi hospital for one year in 2022 were utilized. The study focused on antibiotic therapy, including empiric and targeted approaches, culture sensitivity testing, the use of the APACHE scale for mortality prediction, and changes in antibiotic regimens based on culture reports. Statistical analysis involved Fisher's Exact and ANOVA tests.

RESULT

The age category above 60 emerged with the highest survivorship. Contrary to expectations, age did not seem to correlate significantly with mortality rates. Staphylococcus species was the most prevalent microorganism in this study, disproportionately affecting nonsurvivors 66.7%. The clinical profile comparison between survivors and nonsurvivors offered a multifaceted perspective, with significant differences in vital parameters such as temperature, heart rate, respiratory rate, urine output, FiO2, mean arterial pH, and blood sugar levels. Survivors (44.60%) underwent complete antibiotic regimen changes, a strategy for improved patient outcomes.

CONCLUSIONS

Complex antibiotic combinations were prescribed for broad clinical conditions. These insights pave the way for future research on antibiotic stewardship in ICUs, navigating more effective and targeted treatments.

Risk factors for bloodstream infection among patients admitted to an intensive care unit of a tertiary hospital of Shanghai, China

Blood flow infections (BSIs) is common occurrences in intensive care units (ICUs) and are associated with poor prognosis. The study aims to identify risk factors and assess mortality among BSI patients admitted to the ICU at Shanghai Ruijin hospital north from January 2022 to June 2023. Additionally, it seeks to present the latest microbiological isolates and their antimicrobial susceptibility. Independent risk factors for BSI and mortality were determined using the multivariable logistic regression model. The study found that the latest incidence rate of BSI was 10.11%, the mortality rate was 35.21% and the mean age of patients with BSI was 74 years old. Klebsiella pneumoniae was the predominant bacterial isolate. Logistic multiple regression revealed that tracheotomy, tigecycline, gastrointestinal bleeding, shock, length of hospital stay, age and laboratory indicators (such as procalcitonine and hemoglobin) were independent risk factors for BSI. Given the elevated risk associated with use of tracheotomy and tigecycline, it underscores the importance of the importance of cautious application of tracheostomy and empirical antibiotic management strategies. Meanwhile, the independent risk factors of mortality included cardiovascular disease, length of hospital stay, mean platelet volume (MPV), uric acid levels and ventilator. BSI patients exhibited a significant decrease in platelet count, and MPV emerged as an independent factor of mortality among them. Therefore, continuous monitoring of platelet-related parameters may aid in promptly identifying high-risk patients and assessing prognosis. Moreover, monitoring changes in uric acid levels may serve as an additional tool for prognostic evaluation in BSI patients.

Antimicrobial Resistance and Associated Risk Factors of Gram-Negative Bacterial Bloodstream Infections in Tikur Anbessa Specialized Hospital, Addis Ababa

Background

Bloodstream infections (BSIs) are significant causes of morbidity and mortality in Ethiopia and worldwide. Alarming is the rapid global spread of antimicrobial resistance (AMR) in bacteria.

Objective

To determine the microbial profile, antimicrobial susceptibility pattern, and associated risk factors for bloodstream infections in Tikur Anbessa Specialized Hospital (TASH) Addis Ababa Ethiopia.

Methods

A cross-sectional study was conducted between September 2018 and March 2019. Blood collected twice from each septicemia suspected patient were processed following standard bacteriological procedures. AST was performed by using the disk diffusion test according to CLSI 2017 and 2018 guidelines. Data captured in Epidata were cleaned and analyzed by SPSS version 21 software.

Results

The prevalence of BSI was 28.06% and a higher proportion of pathogene detected were gram-negative bacteria (GNB) (54.5%) and gram-positive bacteria (GPB) (45.43%). The most abundant bacterial species were Klebsiella pneumoniae 17.6%, CoNS 15.2%, and Acinetobacter spp 11.0%. Culture positivity was associated with age below 6 years, neonates AOR p=<0.001, infants AOR p=<0.001, Pre-school P=0.002, ICU admission COR p=<0.001, length of admission >5 days COR P=0.016, temperature greater than 38°C, AOR p=0.013, instrument usage during medical care AOR, p=<0.001, chronic illness AOR p=0.027, and neonatal incubation AOR p=0.013. GNB average drug resistance rate was 57.9% of the commonly used antibiotics and the most efficient and inefficient drugs were amikacin (10.8%) and ampicillin (94.6%). The gram-negative isolates showed a 95.3% rate of multi-drug resistance; and MDR, XDR, and PDR were observed at 55.8%, 32.2%, and 7.3%, of isolates respectively. This finding shows children especially neonates were highly affected by drug resistant BSI.

Conclusion

Pediatric patients and ICU patients are more affected by BSI, and drug-resistant bacteria are a major problem. Therefore, appropriate intervention approaches need to be implemented.

Clinical factors predictive of Gram-negative bloodstream infection at the Emergency Department

INTRODUCTION

Bloodstream infection is a common condition at the Emergency Department (ED). Appropriate antibiotic therapy is also crucial for patients with bloodstream infection particularly at the ED. This study therefore aimed to find clinical factors predictive of types of bacterial pathogens in bloodstream infection patients presenting at the ED focused on Gram-negative bacterial infections.

METHODS

This was a retrospective study. The inclusion criteria were adult patients who were suspected for bloodstream infection defined by blood culture collection presenting at the ED and intravenous antibiotics were initiated during the ED visits. The study period was between January 1st, 2016 and December 31st, 2018. Clinical data of the eligible patients were retrieved from the ED database. Factors associated with Gram-negative infection were calculated by logistic regression analysis.

RESULTS

There were 727 patients at the ED who had positive blood culture for bacteria. Of those, 504 patients (69.33%) had positive blood culture for Gram-negative bacteria. There were three independent factors for Gram-negative infection including sex, solid organ malignancy, and body temperature. The highest adjusted odds ratio (95% confidence interval) was 2.004 (1.330, 3.020) for solid organ malignancy.

CONCLUSIONS

Gram-negative bacterial infection was more prominent than Gram-positive bacterial infection in patients presenting at the ED (69.33%). Solid organ malignancy, being female, and a high body temperature were independent factors of Gram-negative bacterial infection.

Moving from predicting hospital deaths by antibiotic-resistant bloodstream bacteremia toward actionable risk reduction using machine learning on electronic health records

Drug-resistant bacterial infections are a global health concern with high mortality and limited treatment options. Several clinical risk-severity scores are available, e.g. qPitt, but their predictive performance is moderate. Here, we leveraged machine learning and electronic health records (EHRs) to improve prediction of mortality due to bloodstream infection with Klebsiella pneumoniae. We tested the qPitt score and new EHR variables (either expert-chosen or the full set of diagnostic codes), fitting LASSO, boosted logistic regression (BLR), support vector machines, decision trees, and random forests. The qPitt score showed moderate discriminative ability (AUROC=0.63), whilst machine learning models significantly improved its performance (best AUROC by BLR 0.80 for expert-chosen and 0.88 for full code set). Similar results were obtained in critically ill patients, and when excluding potential non-causal variables to evaluate an actionable model. In conclusion, current risk scores for bacteremia mortality can be improved and, with opportune causal modelling, considered for deployment in clinical decision-making.

The Distribution and Source of MRDOs Infection: A Retrospective Study in 8 ICUs, 2013-2019

Background

To analyze the distribution and source of MDROs infection in the ICUs and to provide a basis for formulating more effective prevention and control programs for MDROs.

Methods

A retrospective investigation was conducted on MDROs infection in 8 ICUs of a large tertiary hospital from July 2013 to June 2019. A total of 2629 strains of MDROs isolated from 1701 inpatients were selected for analysis. The MDROs of the 8 ICUs were divided into two types of four categories according to source: out-of-hospital (out-of-hospital transfer and community acquisition) and in-hospital (in-hospital transfer and department acquisition) infections.

Results

CRAB (41.84%) and CRE (35.07%) accounted for the majority of the infecting MDROs. The detection rates of MRSA, CRAB, CRPA and CRE were 61.24%, 83.75%, 43.01% and 30.15%, respectively. The top three infection sites of MDROs were the lower respiratory tract (81.10%), blood (6.70%) and abdominal cavity (5.80%). The out-of-hospital and in-hospital infection rates of MDROs were 50.51% and 49.49%, respectively; the out-of-hospital infection rates for MRSA, CRAB, CRPA and CRE were 43.56%, 55.91, 64.44% and 44.58%, respectively. The proportions of MRSA, CRAB, CRPA and CRE infections contracted in the department were 40.98%, 36.27%, 25.56% and 46.62%, respectively. There was a statistically significant difference between comprehensive ICU and specialized ICU wards as sources for CRAB infections (P < 0.001).

Conclusion

The main source of MDROs in the ICU is not the hospital itself entirely. It is particularly important to strengthen the identification of MDRO sources and implement more effective and accurate infection prevention and control measures.

Bloodstream Infections in Hospitalized Patients with COVID-19: A Systematic Review and Meta-Analysis

Background: Little is known about the occurrence of bloodstream infections in hospitalized patients with COVID-19 and the related clinical consequences. The aim of this systematic review and meta-analysis was to estimate the pooled occurrence of BSIs among hospitalized patients with COVID-19 and mortality of this patient population. Methods: A systematic search was performed on PubMed, EMBASE, and Web of Science from inception to 19 April 2021. The primary outcome was the occurrence of BSIs among hospitalized patients with COVID-19. The secondary outcome was mortality at the longest available follow-up. Results: Forty-six studies met the inclusion criteria, with a total of 42,694 patients evaluated. The estimated occurrence of BSIs was 7.3% (95% CI 4.7–1.1%) among hospitalized patients with COVID-19, with a mortality rate of 41% (95% CI 30%–52.8%). The subgroup analysis conducted on patients admitted to ICU provided an estimated occurrence of 29.6% (95% CI 21.7%–38.8%). A higher occurrence of BSI was observed in patients with COVID-19, in comparison with patients without COVID-19 (OR 2.77; 95% CI 1.53–5.02; p < 0.001). Conclusions: Our analysis estimated the occurrence of BSIs among hospitalized patients with COVID-19 at around 7%. A four-times higher occurrence was estimated among patients admitted to ICU.

Hospital Acquired Bloodstream Infection by Multi Drug Resistant Organisms-Alarming and Challenging Issue in the Intensive Care Units at Present Era

Hospital-acquired bloodstream infections (BSIs) cause high mortality in the intensive care units (ICUs) compared to wards. Furthermore, the isolation of multidrug resistant (MDR) organisms in ICUs add to the gravity of the condition making the treatment a bigger challenge. The present study was aimed to evaluate the prevalence, spread, and the possible MDR organisms contributing to ICU-acquired BSI & the source of the secondary BSI in the ICUs. A prospective study was conducted in four ICU of tertiary teaching hospital over a period of six months. Patient that developed features of BSI within 48 hours after hospital admission were included in the present study Blood culture was performed by an automated BacT/ALERT®3D system. The source of secondary BSI was identified by analysing culture results for the samples other than blood. These samples were taken within 48 hours of the patient’s blood culture test being positive. A total of 50 patients (25%) had an ICU acquired bloodstream infection. Out of 50 patients, 74% of them had bacterial etiology. Thirty one patients (62%) among them developed multidrug resistant bacteraemia. Fifty six percent of Gram negative bacilli were multi drug resistant. The resistance to carbapenem was 42%. The most common MDR Gram negative isolate was identified as Klebsiella pneumoniae (n=12; 38.7%,) and the most common source was pulmonary infection (26.7% (n=12). 42% of isolates in our study were carbapenem resistant suggesting the need for a proper antibiotic policy in the ICUs. Prolonged stay in the ICU with mechanical ventilation was the critical risk factor and ICU mortality was high (38%).

Antibiotic Resistant Bacterial Pathogens Associated with Blood Stream Infections and Urinary Tract Infections among Intensive Care Unit Patients

Blood Stream Infection (BSI) and Urinary Tract Infection (UTI) being leading causes of morbidity and mortality represent a common complication among critically ill patients. During the last decade, clinicians have observed a rising occurrence of BSIs due to bacterial resistance. Likewise, catheter-associated UTI is a main cause of morbidity and mortality affecting all age groups. Coliforms happen to be the prominent pathogens among our ICU admitted patients. It was alarming to notice 42.9% resistance to tigecycline among K. pneumoniae isolated from blood. K. pneumoniae isolates cultured from urine of ICU patients uniformly displayed 75% resistance to ciprofloxacin, ceftriaxone, cefoxitin and cefepime. Interestingly, it is of respite to observe 85.7% K. pneumoniae isolated from blood and 75% K. pneumoniae isolated from urine being susceptible to a conventional antibiotic, gentamicin. Escherichia coli isolated from urine were 100% susceptible to carbapenems and 91.75% were susceptible to tigecycline. Overall, 90% of Pseudomonas aeruginosa were susceptible to nitrofurantoin. The rapid spread of these MDR pathogens demands for national and regional guidelines. Policies to treat ICU related infections in UAE should be designed based on local microbiological data and resistance profiles of pathogens.

Epidemiology and Risk Factors Associated With Mortality in Consecutive Patients With Bacterial Bloodstream Infection: Impact of MDR and XDR Bacteria

Background

 Mortality related to bloodstream infections (BSIs) is high. The epidemiology of BSIs is changing due to the increase in multidrug resistance, and it is unclear whether the presence of multidrug-resistant (MDR) organisms, per se, is an independent risk factor for mortality. Our objectives were, first, to describe the epidemiology and outcome of BSIs and, second, to determine the risk factors associated with mortality among patients with BSI.

Methods

 This research used a single-center retrospective observational study design. Patients were identified through microbiological reports. Data on medical history, clinical condition, bacteria, antimicrobial therapy, and mortality were collected. The primary outcome was crude mortality at 30 days. The relationships between mortality and demographic, clinical, and microbiological variables were analyzed by multivariate analysis.

Results

 A total of 1049 inpatients were included. MDR bacteria were isolated in 27.83% of patients, where 2.14% corresponded to an extremely drug-resistant (XDR) isolate. The crude mortality rates at days 7, 30, and 90 were 12.11%, 25.17%, and 36.13%, respectively. Pitt score >2, lung and abdomen as site of infection, and XDR Pseudomonas aeruginosa were independent risk factors for 7-, 30-, and 90-day mortality. Charlson score >4, carbapenem-resistant Klebsiella pneumoniae, and XDR Acinetobacter baumannii were independent risk factors for 30- and 90-day mortality. Infection by XDR gram-negative bacteria, Charlson score >4, and immunosuppression were independent risk factors for mortality in patients who were stable at the time of BSI.

Conclusions

 BSI is an event with an extreme impact on mortality. Patients with severe clinical condition are at higher risk of death. The presence of XDR gram-negative bacteria in blood is strongly and independently associated with patient death.

High prevalence of atypical virulotype and genetically diverse background among Pseudomonas aeruginosa isolates from a referral hospital in the Brazilian Amazon

Pseudomonas aeruginosa is an opportunistic pathogen causing different types of infections, particularly in intensive care unit patients. Characteristics that favor its persistence artificial environments are related to its high adaptability, wide arsenal of virulence factors and resistance to several antimicrobial classes. Among the several virulence determinants, T3SS stands as the most important due to the clinical impact of exoS and exoU genes in patient’s outcome. The molecular characterization of P. aeruginosa isolates helps in the comprehension of transmission dynamics and enhance knowledge of virulence and resistance roles in infection process. In the present study, we investigated virulence and resistance properties and the genetic background of P. aeruginosa isolated from ICUs patients at a referral hospital in Brazilian Amazon. A total of 54 P. aeruginosa isolates were characterized by detecting 19 virulence-related genes, antimicrobial susceptibility testing, molecular detection of β-lactamase-encoding genes and genotyping by MLST and rep-PCR. Our findings showed high prevalence of virulence-related markers, where 53.7% of the isolates presented at least 17 genes among the 19 investigated (P = 0.01). The rare exoS⁺/exoU⁺ cytotoxic virulotype was detected in 55.6% of isolates. Antimicrobial susceptibility testing revealed percentages of antibiotic resistance above 50% to carbapenems, cephalosporins and fluoroquinolones associated to MDR/XDR isolates. Isolates harboring both bla_SPM-1 and bla_OXA genes were also detected. Genotyping methods demonstrated a wide genetic diversity of strains spread among the different intensive care units, circulation of international MDR/XDR high-risk clones (ST111, ST235, ST244 and ST277) and emergence of seven novel MLST lineages. Finally, our findings highlight the circulation of strains with high virulence potential and resistance to antimicrobials and may be useful on comprehension of pathogenicity process, treatment guidance and establishment of strategies to control the spread of epidemic P. aeruginosa strains.

An African perspective on the prevalence, fate and effects of carbapenem resistance genes in hospital effluents and wastewater treatment plant (WWTP) final effluents: A critical review

This article provides an overview of the antibiotic era and discovery of earliest antibiotics until the present day state of affairs, coupled with the emergence of carbapenem-resistant bacteria. The ways of response to challenges of antibiotic resistance (AR) such as the development of novel strategies in the search of new antibiotics, designing more effective preventive measures as well as the ecology of AR have been discussed. The applications of plant extract and chemical compounds like nanomaterials which are based on recent developments in the field of antimicrobials, antimicrobial resistance (AMR), and chemotherapy were briefly discussed. The agencies responsible for environmental protection have a role to play in dealing with the climate crisis which poses an existential threat to the planet, and contributes to ecological support towards pathogenic microorganisms. The environment serves as a reservoir and also a vehicle for transmission of antimicrobial resistance genes hence, as dominant inhabitants we have to gain a competitive advantage in the battle against AMR.

Epidemiology and Prognosis of Intensive Care Unit-Acquired Bloodstream Infection

Intensive care unit–acquired bloodstream infections (ICU-BSI) are frequent and are associated with high morbidity and mortality rates. We conducted this study to describe the epidemiology and the prognosis of ICU-BSI in our ICU and to search for factors associated with mortality at 28 days. For this, we retrospectively studied ICU-BSI in the ICU of the Cayenne General Hospital, from January 2013 to June 2019. Intensive care unit–acquired bloodstream infections were diagnosed in 9.5% of admissions (10.3 ICU-BSI/1,000 days). The median delay to the first ICU-BSI was 9 days. The ICU-BSI was primitive in 44% of cases and secondary to ventilator-acquired pneumonia in 25% of cases. The main isolated microorganisms were Enterobacteriaceae in 67.7% of patients. They were extended-spectrum beta-lactamase (ESBL) producers in 27.6% of cases. Initial antibiotic therapy was appropriate in 65.1% of cases. Factors independently associated with ESBL-producing Enterobacteriaceae (ESBL-PE) as the causative microorganism of ICU-BSI were ESBL-PE carriage before ICU-BSI (odds ratio [OR]: 7.273; 95% CI: 2.876–18.392; P < 0.000) and prior exposure to fluoroquinolones (OR: 4.327; 95% CI: 1.120–16.728; P = 0.034). The sensitivity of ESBL-PE carriage to predict ESBL-PE as the causative microorganism of ICU-BSI was 64.9% and specificity was 81.2%. Mortality at 28 days was 20.6% in the general population. Factors independently associated with mortality at day 28 from the occurrence of ICU-BSI were traumatic category of admission (OR: 0.346; 95% CI: 0.134–0.894; P = 0.028) and septic shock on the day of ICU-BSI (OR: 3.317; 95% CI: 1.561–7.050; P = 0.002). Mortality rate was independent of the causative organism.

A prospective multicenter study on the evaluation of antimicrobial resistance and molecular epidemiology of multidrug-resistant Acinetobacter baumannii infections in intensive care units with clinical and environmental features

BACKGROUND

Multidrug-resistant (MDR) Acinetobacter baumannii infections are considered as emerging nosocomial infections particularly in patients hospitalized in intensive care units (ICUs). Therefore, reliable detection of MDR strains is crucial for management of treatment but also for epidemiological data collections. The purpose of this study was to compare antimicrobial resistance and the clonal distribution of MDR clinical and environmental A. baumannii isolates obtained from the ICUs of 10 different hospitals from five geographical regions of Turkey in the context of the demographic and clinical characteristics of the patients.

METHODS

A multicenter-prospective study was conducted in 10 medical centers of Turkey over a 6 month period. A total of 164 clinical and 12 environmental MDR A. baumannii isolates were included in the study. Antimicrobial susceptibility testing was performed for amikacin (AN), ampicillin-sulbactam (SAM), ceftazidime (CAZ), ciprofloxacin (CIP), imipenem (IMP) and colistin (COL) by microdilution method and by antibiotic gradient test for tigecycline (TIG). Pulsed-field gel electrophoresis (PFGE) was performed to determine the clonal relationship between the isolates. The detection of the resistance genes, bla_OXA-23, bla_OXA-24, bla_OXA-51, bla_OXA-58, bla_IMP, bla_NDM, bla_KPC, bla_OXA-48 and bla_PER-1 was carried out using the PCR method.

RESULTS

The mortality rate of the 164 patients was 58.5%. The risk factors for mortality included diabetes mellitus, liv1er failure, the use of chemotherapy and previous use of quinolones. Antimicrobial resistance rates for AN, SAM, CAZ, CIP, IMP, COL and TIG were 91.8%, 99.4%, 99.4%, 100%, 99.4%, 1.2% and 1.7% respectively. Colistin showed the highest susceptibility rate. Four isolates did not grow on the culture and were excluded from the analyses. Of 172 isolates, 166 (96.5%) carried bla_OXA-23, 5 (2.9%) bla_OXA-58 and one isolate (0.6%) was positive for both genes. The frequency of bla_PER-1 was found to be 2.9%. None of the isolates had bla_IMP, bla_KPC, bla_NDM and bla_OXA-48 genes. PFGE analysis showed 88 pulsotypes. Fifteen isolates were clonally unrelated. One hundred fifty-seven (91.2%) of the isolates were involved in 14 different clusters.

CONCLUSIONS

Colistin is still the most effective antibiotic for A. baumannii infections. The gene bla_OXA-23 has become the most prevalent carbapenemase in Turkey. The distribution of invasive A. baumannii isolates from different regions of Turkey is not diverse so, infection control measures at medical centers should be revised to decrease the MDR A. baumannii infections across the country. The results of this study are expected to provide an important baseline to assess the future prophylactic and therapeutic options.

Multiplex polymerase chain reaction to diagnose bloodstream infections in patients after cardiothoracic surgery

Background

Sepsis and other infectious complications are major causes of mortality and morbidity in patients after cardiac surgery. Whereas conventional blood culture (BC) suffers from low sensitivity as well as a reporting delay of approximately 48–72 h, real-time multiplex polymerase chain reaction (PCR) based technologies like “SeptiFast” (SF) might offer a fast and reliable alternative for detection of bloodstream infections (BSI). The aim of this study was to compare the performance of SF with BC testing in patients suspected of having BSI after cardiac surgery.

Methods

Two hundred seventy-nine blood samples from 169 individuals with suspected BSI were analyzed by SF and BC. After excluding results attributable to contaminants, a comparison between the two groups were carried out. Receiver operating characteristic (ROC) curves were generated to determine the accuracy of clinical and laboratory values for the prediction of positive SF results.

Results

14.7% (n = 41) of blood samples were positive using SF and 17.2% (n = 49) using BC (n.s. [p > 0.05]). In six samples SF detected more than one pathogen. Among the 47 microorganisms identified by SF, only 11 (23.4%) could be confirmed by BC. SF identified a higher number of Gram-negative bacteria than BC did (28 vs. 12, χ² = 7.97, p = 0.005). The combination of BC and SF increased the number of detected microorganisms, including fungi, compared to BC alone (86 vs. 49, χ² = 13.51, p < 0.001). C-reactive protein (CRP) (21.7 ± 11.41 vs. 16.0 ± 16.9 mg/dl, p = 0.009), procalcitonin (28.7 ± 70.9 vs. 11.5 ± 30.4 ng/dl, p = 0.015), and interleukin 6 (IL 6) (932.3 ± 1306.7 vs. 313.3 ± 686.6 pg/ml, p = 0.010) plasma concentrations were higher in patients with a positive SF result. Using ROC analysis, IL-6 (AUC 0.836) and CRP (AUC 0.804) showed the best predictive values for positive SF results.

Conclusion

The SF test represent a valuable method for rapid etiologic diagnosis of BSI in patients after cardiothoracic surgery. In particular this method applies for individuals with suspected Gram-negative blood stream. Due to the low performance in detecting Gram-positive pathogens and the inability to determine antibiotic susceptibility, it should be used in addition to BC only (Pilarczyk K, et al., Intensive Care Med Exp ,3(Suppl. 1):A884, 2015).

Microbial contamination of keyboards and electronic equipment of ICU (Intensive Care Units) in Kashan University of medical sciences and health service hospitals

Microbial contamination of computer keyboards and inanimate surfaces of electronic equipment in ICU (Intensive Care Units) can have a significant role for ICU-acquired colonization and a spectrum of nosocomial infections. The aim of this study was to survey the incidence of bacterial contamination and the distribution of species of computer keyboards and inanimate surfaces of bed side equipment in ICUs in Kashan University of medical sciences and health service hospitals. This descriptive, cross-sectional study was done on 75 computer keyboards and inanimate surfaces electronic equipment in 5 ICUs during 2016-2017. Samples were collected from computer keyboards and electronic equipment with normal saline rinsed swabs. Samples were Cultivated on Blood Agar (BA), and MacConkey Agar (MAC) and growing bacteria were identified based on their morphology and biochemical properties. Seventy six (76%) out of 75 computer Keyboards and electronic equipment were contaminated with bacteria and fungi. The most contamination pertained to gram positive bacteria (70.7%) and the most isolated bacteria were coagulase-negative staphylococci. The highest contamination rates were found on computer keyboards and electronic equipment of which were nurses. •This study demonstrates that monitoring inanimate surfaces and considering these surfaces as source of nosocomial infections is necessary.•In total, Seventy six (76%) out of 75 computer keyboards and electronic equipment in ICUs had positive culture.•It can be concluded that it is necessary for ICUs of Kashan university of medical sciences and Health service hospitals to have practical and regular program to reduce nosocomial infections.

Carbapenem-resistant Gram-negative bacteria associated with catheter-related bloodstream infections in three intensive care units in Egypt

We aimed to identify the carbapenem-resistant Gram-negative bacteria (GNB) causing catheter-related bloodstream infections (CRBSI) in intensive care units (ICU) in a tertiary care Egyptian hospital, to study their resistance mechanisms by phenotypic and genetic tests, and to use ERIC-PCR for assessing their relatedness. The study was conducted over 2 years in three ICUs in a tertiary care hospital in Egypt during 2015-2016. We identified 194 bloodstream infections (BSIs); 130 (67.01%) were caused by GNB, of which 57 were isolated from CRBSI patients (73.84%). Identification of isolates was performed using conventional methods and MALDI-TOF MS. Antimicrobial susceptibility testing (AST) was done by disc diffusion following CLSI guidelines. Phenotypic detection of carbapenemases enzymes activity was by modified Hodge test and the Carba-NP method. Isolates were investigated for the most common carbapenemases encoding genes bla_KPC, bla_NDM, and bla_OXA-48 using multiplex PCR. Molecular typing of carbapenem-resistant isolates was done by ERIC-PCR followed by sequencing of common resistance genes. The overall rate of CRBSI in our study was 3.6 per 1000 central venous catheter (CVC) days. Among 57 Gram-negative CRBSI isolates, Klebsiella pneumoniae (K. pneumoniae) was the most frequently isolated (27/57; 47.4%), of which more than 70% were resistant to Meropenem. Phenotypic tests for carbapenemases showed that 37.9% of isolates were positive by modified Hodge test and 63.8% by Carba-NP detection. Multiplex PCR assay detected the bla_NDM in 28.6% of the isolates and bla_KPC in 26.8%, bla_NDM and bla_KPC were detected together in the same isolate in 5.6%, while bla_OXA-48-like were not detected. ERIC-PCR detected limited genetic relatedness between K. pneumoniae isolates. Elevated resistance rates were observed to all antibiotics including carbapenems among K. pneumoniae isolates causing CRBSI. ERIC-PCR showed that the resistant isolates were mainly polyclonal. Our results call for reinforcement of antimicrobial stewardship and measures to prevent CRBSI.

Immune stealth-driven O2 serotype prevalence and potential for therapeutic antibodies against multidrug resistant Klebsiella pneumoniae

Emerging multidrug-resistant bacteria are a challenge for modern medicine, but how these pathogens are so successful is not fully understood. Robust antibacterial vaccines have prevented and reduced resistance suggesting a pivotal role for immunity in deterring antibiotic resistance. Here, we show the increased prevalence of Klebsiella pneumoniae lipopolysaccharide O2 serotype strains in all major drug resistance groups correlating with a paucity of anti-O2 antibodies in human B cell repertoires. We identify human monoclonal antibodies to O-antigens that are highly protective in mouse models of infection, even against heavily encapsulated strains. These antibodies, including a rare anti-O2 specific antibody, synergistically protect against drug-resistant strains in adjunctive therapy with meropenem, a standard-of-care antibiotic, confirming the importance of immune assistance in antibiotic therapy. These findings support an antibody-based immunotherapeutic strategy even for highly resistant K. pneumoniae infections, and underscore the effect humoral immunity has on evolving drug resistance.

Therapeutics to combat multidrug-resistant bacteria such as Klebsiella pneumoniae are needed. Here the authors show immune evasion drives lipopolysaccharide O2 serotype expansion in multidrug-resistant isolates, and anti-O-antigen human monoclonal antibodies synergize with antibiotics to protect mice from infection.

Encapsulation of curcumin in polymeric nanoparticles for antimicrobial Photodynamic Therapy

Curcumin (CUR) has been used as photosensitizer in antimicrobial Photodynamic Therapy (aPDT). However its poor water solubility, instability, and scarce bioavalibility hinder its in vivo application. The aim of this study was to synthesize curcumin in polymeric nanoparticles (NP) and to evaluate their antimicrobial photodynamic effect and cytoxicity. CUR in anionic and cationic NP was synthesized using polylactic acid and dextran sulfate by the nanoprecipitation method. For cationic NP, cetyltrimethylammonium bromide was added. CUR-NP were characterized by physicochemical properties, photodegradation, encapsulation efficiency and release of curcumin from nanoparticles. CUR-NP was compared with free CUR in 10% dimethyl sulfoxide (DMSO) as a photosensitizer for aPDT against planktonic and biofilms (mono-, dual- and triple-species) cultures of Streptococcus mutans, Candida albicans and Methicillin-Resistant Staphylococcus aureus. The cytotoxicity effect of formulations was evaluated on keratinocytes. Data were analysed by parametric (ANOVA) and non-parametric (Kruskal-Wallis) tests (α = 0.05). CUR-NP showed alteration in the physicochemical properties along time, photodegradation similar to free curcumin, encapsulation efficiency up to 67%, and 96% of release after 48h. After aPDT planktonic cultures showed reductions from 0.78 log₁₀ to complete eradication, while biofilms showed no antimicrobial effect or reductions up to 4.44 log₁₀. Anionic CUR-NP showed reduced photoinactivation of biofilms. Cationic CUR-NP showed microbicidal effect even in absence of light. Anionic formulations showed no cytotoxic effect compared with free CUR and cationic CUR-NP and NP. The synthesized formulations improved the water solubility of CUR, showed higher antimicrobial photodynamic effect for planktonic cultures than for biofilms, and the encapsulation of CUR in anionic NP reduced the cytotoxicity of 10% DMSO used for free CUR.

What Healthcare Workers Should Know about Environmental Bacterial Contamination in the Intensive Care Unit

Intensive care unit- (ICU-) acquired infections are a major health problem worldwide. Inanimate surfaces and equipment contamination may play a role in cross-transmission of pathogens and subsequent patient colonization or infection. Bacteria contaminate inanimate surfaces and equipment of the patient zone and healthcare area, generating a reservoir of potential pathogens, including multidrug resistant species. Traditional terminal cleaning methods have limitations. Indeed patients who receive a bed from prior patient carrying bacteria are exposed to an increased risk (odds ratio 2.13, 95% confidence intervals 1.62-2.81) of being colonized and potentially infected by the same bacterial species of the previous patient. Biofilm formation, even on dry surfaces, may play a role in reducing the efficacy of terminal cleaning procedures since it enables bacteria to survive in the environment for a long period and provides increased resistance to commonly used disinfectants. No-touch methods (e.g., UV-light, hydrogen peroxide vapour) are under investigation and further studies with patient-centred outcomes are needed, before considering them the standard of terminal cleaning in ICUs. Healthcare workers should be aware of the role of environmental contamination in the ICU and consider it in the broader perspective of infection control measures and stewardship initiatives.

Extensively Drug-Resistant Klebsiella pneumoniae Causing Nosocomial Bloodstream Infections in China: Molecular Investigation of Antibiotic Resistance Determinants, Informing Therapy, and Clinical Outcomes

The rise in diversity of antimicrobial resistance phenotypes seen in Klebsiella pneumoniae is becoming a serious antibiotic management problem. We sought to investigate the molecular characteristics and clinical implications of extensively drug-resistant (XDR) K. pneumoniae isolated from different nosocomial bloodstream infections (BSIs) patients from July 2013 to November 2015. Even in combination treatment, meropenem did not protect against mortality of BSIs patients (P = 0.015). In contrast, tigecycline in combination with other antimicrobial agents significantly protected against mortality (P = 0.016). Antimicrobial susceptibility tests, molecular detection of antibiotic resistance determinants, conjugation experiments, multilocus sequence typing (MLST), S1-PFGE, Southern blot, SDS-PAGE, immunoblot analysis, and pulsed-field gel electrophoresis (PFGE) were used to characterize these isolates. These XDR K. pneumoniae strains were resistant to conventional antimicrobials except tigecycline and polymyxin B and co-harbored diverse resistance determinants. rmtB, bla_KPC−2 as well as bla_CTX−M−9 were located on a transferable plasmid of ~54.2 kb and the most predominant replicon type was IncF. 23 of the 35 isolates belonging the predominant clone were found to incorporate the globally-disseminated sequence type ST11, but others including a unique, previously undiscovered lineage ST2281 (allelic profile: 4-1-1-22-7-4-35) were also found and characterized. The porins OmpK35 and OmpK36 were deficient in two carbapenemase-negative carbapenem-resistant strains, suggesting decreased drug uptake as a mechanism for carbapenem resistance. This study highlights the importance of tracking hospital acquired infections, monitoring modes of antibiotic resistance to improve health outcomes of BSIs patients and to highlight the problems of XDR K. pneumoniae dissemination in healthcare settings.

Acinetobacter baumannii Infection in Transfusion Dependent Thalassemia Patients with Sepsis

PURPOSE

To identify the Acinetobacter baumannii infection among transfusion dependent thalassemia patients.

METHODS

A quantitative approach was employed to assess Acinetobacter baumannii infection in transfusion dependent thalassemia patients. Samples were collected from 916 patients, which have shown bacterial growth on MacConkey and blood agar culture media. A. baumannii strains were identified by microbiological methods and Gram's staining. API 20 E kit (Biomerieux, USA) was used for final identification.

RESULTS

From 916 cultured blood specimens, 107 (11.6%) showed growth of A. baumannii. Serum ferritin in thalassemic patients without bacterial infections was 3849.5 ± 1513.5 µg/L versus 6413.5 ± 2103.9 µg/L in those with bacterial infections (p = 0.0001). Acinetobacter baumannii infected patients have shown higher serum ferritin levels (p = 0.0001). Serum ferritin in thalassemic patients was 3849.5 ± 1513.5 µg/L versus 6413.5 ± 2103.9 µg/L in those with bacterial infections (p = 0.0001). Acinetobacter baumannii infected patients showed high serum ferritin levels (p = 0.0001). The clinical symptoms have been found with A. baumannii +ve with a mean and standard deviation of 47 (5.1%) and A. baumannii -ve with mean and standard deviation of 60 (6.5%).

CONCLUSION

Isolation of asymptomatic A. baumannii from the thalassemia patients shows an alarming situation of bacterial infections. A continuous surveillance of transfusion dependent thalassemia patients is recommended for bacterial sepsis.

Temporal trends of the in vitro activity of tigecycline and comparator antibiotics against clinical aerobic bacterial isolates collected in Germany, 2006-2014: results of the Tigecycline Evaluation and Surveillance Trial (TEST)

Given the rapidly changing landscape of antimicrobial resistance, continuous monitoring of antimicrobial susceptibility in clinically relevant bacterial isolates plays an important role in the management of infectious diseases. The Tigecycline Evaluation and Surveillance Trial (TEST) is an ongoing worldwide surveillance programme monitoring the in vitro activity of tigecycline and a panel of representative comparator antibiotics. We report longitudinal susceptibility data on a large set of isolates (n=36,044) from clinically significant bacterial species collected in 25 microbiological laboratories from 2006 to 2014. Trends include a strong increase of carbapenem and levofloxacin resistance in Acinetobacter spp., and smaller increasing rates of ESBL-producing Escherichia coli and vancomycin-resistant enterococci. Across the reporting period, the tigecycline minimum inhibitory concentrations (MICs) at which 50% and 90% of isolates were inhibited remained stable and susceptibility rates were consistently high (93–100%) for all bacterial species.

The GenePOC Platform, a Rational Solution for Extreme Point-of-Care Testing

Extreme point-of-care (POC) testing for infections, as performed (endured) in low-resource settings, developing countries, tropical areas, or in conditions following emergency crises or natural disasters, must be undertaken under environmental, logistic, and societal conditions which impose a significant deal of stress on local human populations and healthcare providers. For disease diagnostics or management, simple and robust biomedical equipment and reagents are required and needed. This chapter aims to overview some of these stresses (requirements) and intends to describe some of the solutions already engineered at the heart of centripetal (centrifugal) microfluidic platforms such as that of GenePOC Inc. to enable rapid, robust, and reproducible nucleic acid-based diagnostics of infectious diseases, to better control the morbidity and mortality of infections and the expanding threat posed by antimicrobial resistance.

Bacterial contamination of inanimate surfaces and equipment in the intensive care unit

Intensive care unit (ICU)-acquired infections are a challenging health problem worldwide, especially when caused by multidrug-resistant (MDR) pathogens. In ICUs, inanimate surfaces and equipment (e.g., bedrails, stethoscopes, medical charts, ultrasound machine) may be contaminated by bacteria, including MDR isolates. Cross-transmission of microorganisms from inanimate surfaces may have a significant role for ICU-acquired colonization and infections. Contamination may result from healthcare workers’ hands or by direct patient shedding of bacteria which are able to survive up to several months on dry surfaces. A higher environmental contamination has been reported around infected patients than around patients who are only colonized and, in this last group, a correlation has been observed between frequency of environmental contamination and culture-positive body sites. Healthcare workers not only contaminate their hands after direct patient contact but also after touching inanimate surfaces and equipment in the patient zone (the patient and his/her immediate surroundings). Inadequate hand hygiene before and after entering a patient zone may result in cross-transmission of pathogens and patient colonization or infection. A number of equipment items and commonly used objects in ICU carry bacteria which, in most cases, show the same antibiotic susceptibility profiles of those isolated from patients. The aim of this review is to provide an updated evidence about contamination of inanimate surfaces and equipment in ICU in light of the concept of patient zone and the possible implications for bacterial pathogen cross-transmission to critically ill patients.