Epidemiology and microbiology of Gram-positive bloodstream infections in a tertiary-care hospital in Beijing, China: a 6-year retrospective study

In vitro Activity of Ceftaroline Against Isolates of Gram-Positive Bacteria from Patients with Bloodstream Infections Collected as a Part of ATLAS Between 2017 and 2020

Purpose

To assess the in vitro activity of ceftaroline and a panel of comparator agents against isolates of Gram-positive bacteria, including Staphylococcus aureus, Streptococcus pneumoniae, β-hemolytic streptococci, and coagulase-negative staphylococci (CoNS) from blood collected in Africa and Middle East (AfME), Asia Pacific (APAC), Europe, Latin America (LATAM), and North America from 2017 to 2020 as a part of the Antimicrobial Testing Leadership and Surveillance (ATLAS) program.

Methods

Susceptibility and minimum inhibitory concentration were determined using broth microdilution for all antimicrobial agents by a central reference laboratory according to the Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines.

Results

Ceftaroline showed good activity (susceptibility ≥89.8%, MIC90 0.008-2 mg/L) against all Gram-positive isolates tested. All isolates of methicillin-susceptible S. aureus, penicillin-susceptible S. pneumoniae, S. agalactiae, S. dysgalactiae, and S. pyogenes were susceptible to ceftaroline (MIC90 0.008-0.25 mg/L). Ceftaroline susceptibility for MRSA isolates was 89.8% globally (MIC90 2 mg/L). Among the comparator agents, all isolates were susceptible to vancomycin, except S. epidermis (susceptibility, 99.9%). Among other agents, daptomycin, linezolid, and tigecycline showed potent activity (susceptibility ≥97.9%, MIC90 0.03-2 mg/L) against all isolates tested.

Conclusion

Ceftaroline showed potent in vitro activity against global bloodstream isolates of Gram-positive bacteria collected between 2017 and 2020. Monitoring and surveillance of global as well as regional longitudinal trends of resistance rates among Gram-positive isolates causing bloodstream infections are important to limit the spread of AMR, establish stewardship measures, and manage and appropriately treat infections.

Four-year variation in pathogen distribution and antimicrobial susceptibility of urosepsis: a single-center retrospective analysis

Background

Urosepsis is a common disease in urology, which is characterized by high treatment costs and high mortality. In the treatment of sepsis, anti-infection therapy is the most important means. However, the effect of empirical anti-infection therapy is often not ideal. Therefore, it is necessary to continuously monitor the prevalence of bacterial isolates in the blood culture of patients with urinary sepsis and their sensitivity to antibacterial drugs. This is of great significance to improve the efficacy of empirical antibiotic therapy for urosepsis.

Objective

To elucidate the landscape of prevailing bacterial profiles and their antimicrobial susceptibilities in urosepsis cases, and to furnish robust clinical evidence to underpin the timely initiation of empirical antibiotic treatment.

Methods

Collect the basic information and blood culture results of patients with urosepsis hospitalized from 2017 to 2020. Retrospective analysis of bacterial species and antimicrobial susceptibility in urosepsis and changes over 4 years.

Results

Gram-negative bacteria (178 isolates, 75.11%) constituted the main pathogens causing urosepsis, followed by Gram-positive bacteria (46 isolates, 19.41%) and fungus (13 isolates, 5.48%). The sensitivity of ertapenem, meropenem, amikacin, and imipenem to Gram-negative bacteria all exceeded 85%. The sensitivity rates of levofloxacin, gentamicin, and ciprofloxacin are decreasing every year (p < 0.05). Tigecycline, vancomycin, and linezolid exhibited excellent sensitivity against Gram-positive bacteria. Among fungi, fluconazole demonstrated universal sensitivity, while itraconazole-resistant isolates have been found, and amphotericin B is still effective.

Conclusion

Analysis of blood culture results of patients more accurately reflected the etiology of urosepsis, mainly Escherichia coli, Enterococcus, and Klebsiella pneumoniae. If there are no definitive blood culture results, empiric treatment of urosepsis should not include fluoroquinolone antibiotics. Cefepime, cefoxitin, and ceftazidime are the most sensitive antibiotics to Gram-negative bacteria besides carbapenem antibiotics. In addition, the current situation regarding extended-spectrum β-lactamase-producing bacteria and carbapenem-resistant Enterobacteriaceae bacteria resistance is extremely concerning with limited therapeutic options available. Strengthening antibiotic management practices and exploring novel antibacterial agents can help mitigate this issue.

Oral antibiotic step-down therapy for nonstaphylococcal gram-positive bloodstream infections

Bloodstream infections traditionally are treated with intravenous (IV) therapy. This study's purpose is to evaluate if oral step-down therapy is noninferior to IV therapy for gram-positive bloodstream infections (GP-BSIs). This retrospective cohort study included patients who received IV therapy and those who received oral step-down therapy for a nonstaphylococcal GP-BSI from 2017 to 2019. The primary endpoint was a composite outcome of 90-day all-cause mortality and clinical failure. A total of 308 patients were included (n = 94, oral; n = 214, IV). The oral step-down group had a lower incidence of 90-day clinical failure (9% vs 14%; P < 0.001). The IV group had a longer hospital stay (4 vs 6 days, P < 0.001); however, there were no significant differences in secondary outcomes. Bivariate analysis found no predictors of 90-day clinical failure. Oral step-down therapy was found to be noninferior to IV therapy.

Epidemiology and outcomes of vancomycin-resistant enterococcus infections: a systematic review and meta-analysis

Vancomycin-resistant enterococci (VRE) cause many infections in the healthcare context. Knowledge regarding the epidemiology and burden of VRE infections, however, remains fragmented. We aimed to summarize recent studies on VRE epidemiology and outcomes in hospitals, long-term-care facilities (LTCFs) and nursing homes worldwide based on current epidemiological reports. We searched MEDLINE/PubMed, the Cochrane Library, and Web of Science for observational studies, which reported on VRE faecium and faecalis infections in in-patients published between January 2014 and December 2020. Outcomes were incidence, infection rate, mortality, length of stay (LOS), and healthcare costs. We conducted a meta-analysis on mortality (PROSPERO registration number: CRD42020146389). Of 681 identified publications, 57 studies were included in the analysis. Overall quality of evidence was moderate to low. VRE incidence was rarely and heterogeneously reported. VRE infection rate differed highly (1-55%). The meta-analysis showed a higher mortality for VRE faecium bloodstream infections (BSIs) compared with VSE faecium BSIs (risk ratio, RR 1.46; 95% confidence interval (CI) 1.17-1.82). No difference was observed when comparing VRE faecium vs VRE faecalis BSI (RR 1.00, 95% CI 0.52-1.93). LOS was higher in BSIs caused by E. faecium vs E. faecalis. Only three studies reported healthcare costs. In contrast to previous findings, our meta-analysis of included studies indicates that vancomycin resistance independent of VRE species may be associated with a higher mortality. We identified a lack of standardization in reporting outcomes, information regarding healthcare costs, and state-of-the-art microbiological species identification methodology, which may inform the set-up and reporting of future studies.

The emergence of multidrug-resistant Gram-positive bloodstream infections in India - a single center prospective cohort study

Introduction

Gram-positive bloodstream infections (BSIs) are an emerging health concern, especially in resource-limited settings. There is a paucity of data regarding the antimicrobial resistance (AMR) pattern of Gram-positive BSIs. The rise in multidrug-resistant infections further convoluted antibiotic selection. We aimed to assess the incidence, clinical and microbiological profile, antimicrobial resistance (AMR) and outcome in Gram-positive BSIs.

Methods

This was a single-center prospective study conducted at a tertiary care hospital in Western India. All patients (age ≥18 years) with culture-proven Gram-positive BSIs were included. Data were collected on all patients' demography, risk factors, AMR and clinical outcome.

Results

A total of 210 clinically significant isolates were grown from July 2020 to December 2021. The incidence of Gram-positive BSIs was 29% (n=61); 55.9% of cases were healthcare-associated, while 44.1% were community-acquired. Coagulase-negative staphylococci (CoNS) were the major isolates (36.1%), followed by Enterococcus spp. (27.9%), methicillin-susceptible Staphylococcus aureus (MSSA) (18%) and methicillin-resistant Staphylococcus aureus (MRSA) (14.7%). The proportion of vancomycin and teicoplanin-resistant CoNS isolates was 13.6% and 19%. Among Enterococcus isolates, the proportion of vancomycin-resistant enterococci (VRE) and linezolid-resistant enterococci (LRE) were 11.8% and 5.9%. The overall mortality in Gram-positive BSIs was 42.6%. Older age, MRSA infection, septic shock, and high NLR were significantly associated with mortality. On the Cox regression model, age ≥65 years (HR: 2.5; 95%CI: 1.1-5.8; p=0.024) and MRSA infection (HR: 3.6; 95%CI: 1.5-8.5; p=0.021) were found as independent predictors of 30-day mortality.

Conclusions

This study found substantial mortality with Gram-positive BSIs, especially MRSA infections. Moreover, the emergence of VRE and LRE is also alarming. Active surveillance of AMR and evaluation of mortality predictors may help overcome the therapeutic challenges in managing BSIs.

Prevalence of Multidrug-Resistant Bacteria in Healthcare-Associated Bloodstream Infections at Hospitals in Riyadh, Saudi Arabia

Bloodstream infection (BSI) prevalence in hospitalized patients has increased owing to the spread of antibiotic-resistant pathogens; moreover, antimicrobial resistance in bacteria is a global problem. Here, BSIs are investigated in several patients at a hospital in Saudi Arabia, and the resistance of bacterial isolates to widely used drugs is determined. Throughout 2020, bacteria isolated from patients were identified and subjected to antibiotic susceptibility testing. In total, 1125 bacterial isolates were obtained from 1039 patients; among them, gram-positive bacteria were significantly more abundant than gram-negative bacteria. The most prevalent bacteria were Staphylococcus epidermidis and Klebsiella pneumoniae. Notably, gram-negative bacteria were mainly isolated from adult patients, and 20.63% of the gram-positive isolates were from pediatric patients, which was significantly higher than the corresponding percentages in elders and adults. The gram-positive isolates were mainly resistant to cephalothin, oxacillin, amoxicillin-clavulanate, and erythromycin and susceptible to penicillin, gentamicin, ciprofloxacin, and vancomycin. Additionally, the gram-negative isolates were mainly resistant to ampicillin, cephalothin, and amoxicillin-clavulanate and susceptible to amikacin, ertapenem, aztreonam, colistin, and trimethoprim-sulfamethoxazole. Consequently, the high prevalence of infective multidrug-resistant bacteria may account as a significant health issue; it is considered a hazard in Riyadh hospitals and must be prevented at all costs.

Risk Factors and Outcome Analysis of Gram-Positive Bacteremia in Critically Ill Patients

Introduction Bloodstream infection (BSI) is a common problem for patients in the intensive care unit (ICU). Nearly 60% of primary bloodstream infections are caused by Gram-positive cocci. Gram-positive bacteria gain access to the bloodstream through invasive procedures and various patient care equipment like catheters, intravenous lines, and mechanical ventilators. S. aureus is considered to be the major cause of septicemia. Knowledge of healthcare-associated infections and the antimicrobial susceptibility patterns of the isolates are crucial in guiding empirical treatment. Methods This prospective observational study was conducted in Medical ICU, Dayanand Medical College & Hospital, Ludhiana over a period of one year (December 2015 to November 2016). Patients whose blood cultures tested positive for Gram-positive bacteria were included in the study. This study was carried out to assess the implications and risk factors for nosocomial BSI and several factors, including the age of the patient, the severity of illness, the presence of catheters, and the microorganisms causing the BSI to independently predict mortality. Chief complaints and risk factors were evaluated. APACHE-II scores were calculated for all patients and outcomes were analyzed. Results In our study, the mean age of patients was 50.93±14.09 years. Central line insertion was found as the most common risk factor (58.7%). A statistically significant correlation was obtained between APACHE-II scores and the presence of risk factors i.e. central line insertion (p-value=0.010) and diabetes mellitus (p-value=0.003). The most common Gram-positive pathogen isolated by blood culture was methicillin-sensitive S. aureus (44.2%). For management, the majority of the patients were prescribed teicoplanin (58.7%). The 28-day overall mortality rate in our study was 52.9%. Conclusion We conclude that independent risk factors like diabetes mellitus, central line insertion, and acute pancreatitis in adult patients with Gram-positive bacteremia were associated with higher mortality. We have also concluded that the administration of early appropriate antibiotics improves patient outcomes.

The Assessment of Antimicrobial Resistance in Gram-Negative and Gram-Positive Infective Endocarditis: A Multicentric Retrospective Analysis

Background and Objectives: Multidrug-resistant microorganisms have made treating bacterial infections challenging. Resistance to antibiotics is expected to overcome efforts to produce new, effective antibacterial medication that is lifesaving in many situations. Infective endocarditis (IE) is a life-threatening infection that affects 5–15 per 100,000 patients annually and requires rapid antibiotic therapy to prevent morbidity and mortality. Materials and Methods: The present research assessed IE cases over five years, from a multicentric database, with the main objective of determining the degree of antibiotic resistance in these patients, stratified by Gram-positive and Gram-negative bacteria. Results: Bad oral hygiene was present in 58.6% of patients from the Gram-negative group (vs. 38.7% in the Gram-positive group). Non-valvular heart disease was identified in approximately 40% of all patients, and valvopathies in approximately 20%. It was observed that 37.9% of Gram-negative IE bacteria were resistant to three or more antibiotics, whereas 20.7% were susceptible. Among Gram-positive infections, S. aureus was the most commonly involved pathogen, with a multidrug-resistant pattern in 11.2% of patients, while Acinetobacter baumannii had the highest resistance pattern of all Gram-negative pathogens, with 27.4% of all samples resistant to three or more antibiotics. Patients with Gram-negative IE were 4.2 times more likely to die. The mortality risk was 4 times higher when bacteria resistant to two or more antibiotics was involved and 5.7 times higher with resistance patterns to three or more antibiotics than the reference group with no antibiotic resistance. Peripheral catheters were the most common cause of multi-resistant IE, followed by heart surgery, dental procedures, and ENT interventions. Conclusions: Even though Gram-positive infections were the most frequent (83.0% of all cases), Gram-negative IE infections are substantially more deadly than Gram-positive IE infections. However, it was also observed that patients with Gram-negative infections were more likely to have underlying comorbidities, be institutionalized, and be underweight. Although the Gram-negative infections were more severe, their resistance patterns were similar to Gram-positive bacteria. As resistance patterns increase, more efforts should be made to prevent a healthcare catastrophe. At the same time, careful prophylaxis should be considered in patients at risk, including those with central catheters, undergoing dental procedures, and with poor oral hygiene.

Clinical Microbial Identification of Severe Oral Infections by MALDI-TOF Mass Spectrometry in Stockholm County: an 11-Year (2010 to 2020) Epidemiological Investigation

Growing evidence suggests that oral infections can modify the course of systemic diseases. To date, epidemiological data on microbial oral infections are scarce. Here, we performed a comprehensive analysis of the trend and microbial diversity in oral infection specimens referred for clinical microbiology analysis from 2010 to 2020. The microbes were isolated by culture and were identified via matrix-assisted laser desorption ionization-time of flight mass spectrometry technology (MALDI-TOF MS) throughout the study period. A total of 1,014 referred samples from dental clinics in Stockholm County with dentoalveolar abscesses and jaw osteomyelitis being the main reason were identified. Overall, the microbial composition was dominated by Firmicutes (51%), followed by Bacteroidetes (19%), Proteobacteria (12%), and Actinobacteria (5%). At the genus level, Streptococcus spp. (36%), Prevotella spp. (18%), and Staphylococcus spp. (11%) were among the most frequently reported. Interestingly, a strong increase in trend was noted for Streptococcus anginosus, Streptococcus mitis, Streptococcus sanguinis, Eikenella corrodens, Actinomyces spp., Aggregatibacter aphrophilus, Staphylococcus epidermidis, and Granulicatella adiacens during the study time (R = 0.66 to 0.89, P < 0.05), and a minor increase was noted for Enterococcus faecalis and Klebsiella spp., whereas steady levels were noted for most of the others. The present study shows the diversity of bacteria that have been involved in dental infections during the last decade in the capital of Sweden, as well as the emerging oral microbiota trend, with clear clinical implications on the oral-systemic link. IMPORTANCE Oral diseases and associated microbes are a risk factor for systemic diseases and can change the courses of these diseases. To date, epidemiological data on microbial oral infections are scarce, and longitudinal reports are lacking. We present for the first time the microbial composition of severe oral bacterial infections determined via the MALDI-TOF mass spectrometry technique in a comprehensive study between 2010 and 2020 (11 years) in Stockholm County. The trend and microbial diversity of oral infections were analyzed on referred clinical microbiological samples and were processed by standardized protocols. Trend increase was noted for Streptococcus anginosus, Streptococcus mitis, Streptococcus sanguinis, Eikenella corrodens, Actinomyces spp., Aggregatibacter aphrophilus, Staphylococcus epidermidis, Granulicatella adiacens, Enterococcus faecalis, and Klebsiella spp. Our results provide new insights into the diversity and trend of oral microbiota that were involved in serious oral infections over the past decade in the capital of Sweden and may influence the oral-systemic link.

Incidence, Clinical Features, and Association with Prognosis of Bloodstream Infection in Pediatric Patients After Percutaneous or Surgical Treatment for Ventricular Septal Defect or Atrial Septal Defect: A Retrospective Cohort Study

INTRODUCTION

Bloodstream infection (BSI) may occur after cardiac procedures, but this has rarely been investigated specifically in pediatric patients after percutaneous or surgical treatment for ventricular septal defect (VSD) or atrial septal defect (ASD) with recent data. The current study aimed to investigate the incidence, clinical features, and association with prognosis of BSI in this patient population.

METHODS

Pediatric patients who received percutaneous or surgical procedure for VSD or ASD between 2010 and 2018 in a large children's hospital in China were retrospectively enrolled via the Pediatric Intensive Care database, but only those who had blood culture records within 24 h after the procedure and who had no prior positive blood culture records were included. BSI after the procedure was identified by reviewing blood culture records, and baseline characteristics associated with BSI were explored by univariable logistic regression. In-hospital mortality and length of hospitalization were studied as prognostic outcomes and compared between patients with and without BSI.

RESULTS

A total of 1340 pediatric patients were included. Among them, 46 (3.43%) patients had BSI within 24 h after the procedure, of which the majority (78.26%, 36/46) were caused by Gram-positive bacteria and 65.22% (30/46) had antibiotic-resistant organisms. Age [odds ratio (OR) 0.98 per 1-month increase, 95% confidence interval (CI) 0.97-1.00, P = 0.021] and antibiotic use within 72 h before the procedure (OR 1.81, 95% CI 1.00-3.26, P = 0.049) were statistically significantly associated with developing BSI. Compared with patients without BSI, there was no statistically significant difference in in-hospital mortality (0.00% versus 0.54%, P = 1.000), but patients with BSI had statistically significantly longer length of hospitalization (median 14.51 versus 12.94 days, P = 0.006), while the association was not statistically significant after adjustment for baseline characteristics by multivariable linear regression (β = 1.73, 95% CI -0.59 to 4.04, P = 0.144).

CONCLUSION

BSI is relatively uncommon in pediatric patients after procedures for VSD or ASD, but a younger age seems a risk factor. Developing BSI appears to be associated with increased length of hospitalization but not in-hospital mortality.

Trends of Bloodstream Infections in a University Hospital During 12 Years

This study aims to investigate trends in bloodstream infections and their antimicrobial susceptibility profiles over 12 years in our hospital. This retrospective study was carried out in the Bursa Uludag University Hospital, Turkey, during 2008–2019. Blood cultures from patients were performed using BACTEC System. Isolates were identified with Phoenix System until 2018 and “matrix-assisted laser desorption ionization time-of-flight mass spectrometry” (MALDI-TOF MS) in 2019. Antibiotic susceptibility testing was performed with Phoenix System. Patient data came from the BD EpiCenter™ data management system. Escherichia coli was found to be the most common Gram-negative (11.6%), and coagulase-negative staphylococci were the most common Gram-positive (10.1%) monomicrobial growth. Overall, there was a significant increase in rates of extended-spectrum β-lactamase positive E. coli (p = 0.014) and Klebsiella pneumonia (p < 0.001), carbapenem-resistant E. coli (p < 0.001), and K. pneumoniae (p < 0.001) and colistin-resistant K. pneumoniae (p < 0.001) and Acinetobacter baumannii (p < 0.001) over 12 years. Carbapenem and colistin resistance has increased dramatically in recent years. We believe that regular monitoring of the distribution of pathogens and antibiotic susceptibility profiles, especially in intensive care units, can contribute to evidence for the increase in resistant microorganisms and help prevent their spread with antimicrobial stewardship and infection control policies.

Molecular Characterization of Staphylococci Recovered from Hospital Personnel and Frequently Touched Surfaces in Tianjin, China

Staphylococci are major hospital-associated pathogens, and the dissemination of methicillin-resistant staphylococci in hospitals poses a great challenge for managing hospital-acquired infections. Little is known about the dissemination of staphylococci recovered from the hospital environment and personnel in China. In this study, antimicrobial susceptibility tests, mecA gene detection, SCCmec typing, and multilocus sequence typing (MLST) were performed to clarify the molecular epidemiology of staphylococci in a large hospital in Tianjin, China. One hundred and ninety-five staphylococci were recovered, and 94% of isolates were resistant to at least one antibiotic. Eighty-five staphylococci were mecA gene-positive, and 40% of them harbored SCCmec IV and V. The genotype of Staphylococcus aureus (S. aureus) was ST25, and the dominant genotype of methicillin-resistant Staphylococcus epidermidis (MRSE) was ST59. Three new sequence types were assigned as ST840, ST841, and ST842. One (2%) frequently touched surface was contaminated by S. aureus, which suggested that environmental contamination occurred in the hospital in China. Nineteen (39%) frequently touched surfaces were contaminated by methicillin-resistant coagulase-negative staphylococci (MRCoNS), and 46% of HP carried MRCoNS. Varied staphylococcal species and antimicrobial-resistance rates were observed between staphylococci that were recovered from hospital personnel and frequently touched surfaces. The transmission of MRSE and S. aureus between hospital personnel and frequently touched surfaces was detected. Hospital items and personnel may act as reservoirs of antimicrobial-resistant staphylococci, and cleaning strategies should be carried out to decrease the dissemination of antimicrobial-resistant staphylococci in hospitals in China.

Occurrence and Resistance Pattern of Gram-Negative Bacteremia and Sepsis in A Tertiary Care Hospital - A Four-Year Study

The rise in antibiotic resistance has been a major source of public health concern. As a result, mortality and morbidity rates have risen significantly. This study was done to identify gram-negative organisms causing bacteremia/sepsis, study their prevalence rates, and antimicrobial resistance patterns, as evidence-based knowledge of gram-negative organisms causing sepsis and their resistance profiles is essential for effective hospital control and better management of infections caused by resistant bacteria. A retrospective study, conducted from January 2016 to December 2019, blood samples were collected using aseptic guidelines and cultured using automated blood culture methods. Biochemical tests were done according to microbiology standard procedures, while antimicrobial testing was done according to CLSI guidelines. A total of 13,808 blood samples were received within the study period of four years. Of the total, 2079 showed significant growth, with 765 being GNB isolates. The most common isolates were Escherichia coli (35.42%), Klebsiella pneumonia (19.74%), Acinetobacter species (9.67%), and other non-fermenting gram-negative bacilli (11.76%). Escherichia coli showed yearly resistance to aminoglycosides, cephalosporins, penicillin, fluoroquinolones, and B-lactam combination agents. Routine surveillance and awareness of the prevalence, etiological agents, and antibiotic resistance of gram-negative bacteria causing bacteremia/sepsis is critical for individual therapy, hospital control, and the effectiveness of preventive interventions.

Reducing infectious complications after allogeneic stem cell transplant

INTRODUCTION

Infections remain a significant problem, in patients undergoing an allogeneic hematopoietic stem-cell transplant (HSCT) and efforts have been made over the years, to reduce the incidence, morbidity and mortality of infectious complications.

AREAS COVERED

This manuscript is focused on the epidemiology, risk factors and prevention of infections after allogeneic HSCT. A systematic literature review was performed using the PubMed database, between November 2019 and January 2020, with the following MeSH terms: stem-cell transplantation, infection, fungal, bacterial, viral, prophylaxis, vaccines, prevention. The authors reviewed all the publications, and following a common revision, a summary report was made and results were divided in three sections: bacterial, fungal and viral infections.

EXPERT OPINION

Different infections occur in the early, intermediate and late post-transplant period, due to distinct risk factors. Improved diagnostic techniques, pre-emtive therapy and better prophylaxis of immunologic complications, have reduced the morbidity and mortality of infections. The role of the gut microbiota is under careful scrutiny and may further help us to identify high-risk patients.

Antimicrobial Susceptibility Trends among Pathogens Isolated from Blood: A 6-Year Retrospective Study from a Tertiary Care Hospital in East Sikkim, India

Background  Bloodstream infections (BSIs) are one of the frequent nosocomial infections among hospitalized patients. To understand the local epidemiology and evolving antimicrobial drug resistance of blood-borne pathogens, we analyzed the distribution and antibiotic sensitivity profile of organisms causing BSI in our hospital-based study. Materials and Methods  We reviewed retrospective data of laboratory-confirmed BSIs, from January 2013 to December 2018. Causative organisms and their antibiotic susceptibility profile of primary and secondary BSI reports were determined from BacT/Alert and Vitek systems findings (bioMérieux). A 6-year multidrug resistance indexing was done to document the resistance pattern of the commonly isolated organisms. Results  A total of 1,340 (10.2%) BSIs were reported from 13,091 blood cultures. Organisms were frequently isolated from the younger population (≤20 years), especially from ages < 1 year (20.8% of total BSIs). Majority of pathogens were bacterial (97.1%) whereas 2.9% were fungal in origin. Monomicrobial growth was recorded in over 98% of BSIs. Gram-positive and gram-negative bacteria isolated were 518 (39.8%) and 783 (60.2%), respectively. Commonly isolated organisms were coagulase-negative Staphylococci (29.4%), Escherichia coli (19.8%), Klebsiella species (13.5%), Salmonella species (9.4%), and Staphylococcus aureus (7.5%). Multidrug-resistance index was observed highest in Acinetobacter species followed by Pseudomonas aeruginosa and S. aureus . Conclusion  Overall, there has been a gradual decline in the reporting of BSI. However, infections by gram-negative bacilli and multidrug-resistant organisms remain persistently high. Ages < 20 years were the vulnerable group, with infants < 1 year contributing to the maximum number of BSI cases caused by both bacteria and fungi. Therefore, additional methods are required to study the origin and causation of these infections, particularly among vulnerable patients.

Quantifying Human Health Risks from Virginiamycin Use in Food Animals in China

Virginiamycin (VM), a streptogramin antibiotic, has been used to promote healthy growth and treat illnesses in farm animals in the United States and other countries. The combination streptogramin Quinupristin-Dalfopristin (QD) was approved in the United States in 1999 for treating patients with vancomycin-resistant Enterococcus faecium (VREF) infections. Many chickens and swine test positive for QD-resistant E. faecium, raising concerns that using VM in food animals might select for streptogramin-resistant strains of E. faecium that could compromise QD effectiveness in treating human VREF infections. Such concerns have prompted bans and phase-outs of VM as growth promoters in the United States and Europe. This study quantitatively estimates potential human health risks from QD-resistant VREF infections due to VM use in food animals in China. Plausible conservative (risk-maximizing) quantitative risk estimates are derived for future uses, assuming 100% resistance to linezolid and daptomycin and 100% prescription rate of QD to high-level (VanA) VREF-infected patients. Up to one shortened life every few decades to every few thousand years might occur in China from VM use in animals, although the most likely risk is zero (e.g., if resistance is not transferred from bacteria in food animals to bacteria infecting human patients). Sensitivity and probabilistic uncertainty analyses suggest that this conclusion is robust to several data gaps and uncertainties. Potential future human health risks from VM use in animals in China appear to be small or zero, even if QD is eventually approved for use in human patients.

Rapid multiplex detection of the resistance genes mecA, vanA and vanB from Gram-positive cocci-positive blood cultures using a PCR-dipstick technique

Introduction. Among the causative agents of bloodstream infections (BSIs), methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) are the key causative pathogens. Their rapid detection directly from Gram-positive cocci-positive blood culture specimens will promote timely treatment and help to implement effective infection control measures.Aim. We aim to develop a PCR-dipstick technique for the rapid detection of MRSA and VRE directly from positive blood culture specimens.Methodology. PCR-dipstick is a PCR-based multiplex detection technique where DNA-DNA hybridization is employed, and the results are interpreted with the naked eye. It was designed to target three drug resistance genes: mecA in MRSA and vanA/vanB in VRE from positive blood culture specimens. A total of 120 clinical isolates were used to evaluate the sensitivity and specificity of PCR-dipstick. Then, PCR-dipstick was examined for MRSA and VRE detection directly from positive blood cultures.Results. PCR-dipstick showed 100 % sensitivity and specificity in detecting mecA, vanA and vanB genes directly from bacterial colonies in comparison with multiplex PCR for genomic DNA followed by agarose gel electrophoresis. Further, it could differentially detect multiple resistant genes in pooled bacterial colonies (n=10). Ultimately, PCR-dipstick could detect MRSA and VRE in positive blood cultures in ~3 h.Conclusion. The results of the current study substantiate that PCR-dipstick can be used as an efficient detection system for MRSA and VRE directly from Gram-positive cocci-positive blood cultures. Its affordability and rapidity indicate that PCR-dipstick can be an effective tool for controlling nosocomial pathogens.

The species distribution, antimicrobial resistance and risk factors for poor outcome of coagulase-negative staphylococci bacteraemia in China

Objective

Coagulase-negative staphylococci (CoNS) are one of the major opportunistic pathogens and the incidence of CoNS bacteraemia is increasing. However, most of the CoNS-positive blood cultures are contaminants rather than true CoNS bacteraemia. In order to minimize contamination, we defined true CoNS bacteraemia as the patient that has two or more identical CoNS-positive blood cultures drawn within 48 h in this study and the objective of this study was to analyse the species distribution and antibiotic resistance and to identify risk factors for 30-day mortality of the true CoNS-bacteraemia.

Method

By reviewing the electronic medical database, this study retrospectively analysed patients diagnosed as CoNS bacteraemia by blood cultures in a comprehensive tertiary care hospital in China from January 1, 2014, to December 31, 2017.

Result

A total of 1241 patients with 1562 episodes of CoNS-positive blood cultures were recorded in the database but only 157 patients were finally diagnosed as true CoNS bacteraemia after contaminants were excluded. All these 157 patients (12.7%, 157/1241) had bacteraemia-related clinical symptoms. Among the 157 patients, the most common species were Staphylococcus hominis (40.8%), Staphylococcus epidermidis (36.3%) and Staphylococcus capitis (11.5%). The antimicrobial susceptibility tests showed that all CoNS had a high rate of resistance to penicillin (94.9%), oxacillin (93.6%) and erythromycin (92.4%). Resistance to gentamicin (22.3%) and rifampicin (10.8%) was low, and none of the bacteria were resistant to vancomycin or linezolid. The 30-day mortality of patients with CoNS bacteraemia was up to 12.7% (20/157), and the multivariate logistics regression analysis showed that chronic renal failure (OR 5.9, 95% CI 1.6–21.5, p = 0.007) and chronic liver failure (OR 4.0, 95% CI 1.2–13.1, p = 0.024) were both the significant independent risk factors for the 30-day mortality of CoNS bacteraemia.

Conclusion

Staphylococcus hominis and Staphylococcus epidermidis were the most common species in CoNS bacteraemia. All CoNS had high multi-drug resistance, but gentamicin and rifampicin had a relatively lower resistance and could be considered as alternative antibiotics for anti-CoNS bacteraemia in addition to vancomycin and linezolid. Additionally, patients with chronic renal failure or chronic liver failure have a higher 30-day mortality after the onset of CoNS bacteraemia.