Risk factors for drug-resistant bacterial pneumonia in older patients hospitalized with pneumonia in a Chinese population

Risk of Multidrug-Resistant Pathogens in Severe Community-Acquired Pneumonia

Severe community-acquired pneumonia (SCAP) is difficult to treat when caused by difficult-to-treat (DTR) pathogens because of limited treatment options and poorer clinical outcomes. Over time, several predictive scoring systems based on risk factors for infection with multidrug resistant pathogens have been developed. We reviewed the available tools for identifying DTR pathogens as the cause of SCAP, both predictive scoring systems and rapid diagnostic methods, to develop management strategies aimed at early identification of DTR pathogens, reducing broad-spectrum antibiotic use and improving clinical outcomes. The scoring systems reviewed show considerable heterogeneity among them at the level of the region studied, the definition of risk factors, as well as which DTR pathogens are the target pathogens. The models described have shown limited effectiveness in reducing inappropriate antibiotic treatment or improving patient outcomes by themselves. However, predictive models could serve as a first step in identifying DTR pathogen infections as part of a larger detection algorithm. Rapid diagnostic tools, such as multiplex polymerase chain reaction, would be useful for the rapid identification of pneumonia-causing pathogens and their resistance mechanisms. In resource-limited settings, rapid tests should be limited to patients at high risk of developing SCAP due to DTR pathogens. We propose an integrative algorithm based on the different scores, taking into account local epidemiological data, where ideally each center should have an antimicrobial stewardship program.

Effects of Chengqi Decoction on Complications and Prognosis of Patients with Pneumonia-Derived Sepsis: Retrospective Cohort Study

Purpose

A specific and efficacious method for treatment of pneumonia-derived sepsis is lacking. Chengqi decoction has been used for treatment of pneumonia-derived sepsis, but a clinical trial on patients with pneumonia-derived sepsis is lacking, a gap in the literature that we sought to fill. Patients and Methods. 282 patients with pneumonia-derived sepsis admitted to the intensive care unit of our hospital were selected. They were divided into the treatment group (141 cases) and control group (141 cases). Both groups underwent conventional treatment, but Chengqi decoction (in the form of enema) was given to the treatment group. Mortality, morbidity (abdominal distension and gastrointestinal bleeding), duration of antibiotic use, and use of vasoactive agents were documented 28 days after the drug was used.

Results

The treatment group reduced mortality and morbidity (abdominal distension) (P < 0.05). After adjustment for significant covariates, 28-day survival was similar for the whole group (hazard ratio (HR): 0.48; 95% confidence interval (CI): 0.23–0.97; P=0.037), for the subgroup (n = 120) with Acute Physiology and Chronic Health Evaluation II score ≥25 (HR: 0.180; 95% CI: 0.032–0.332; P=0.039) and for the subgroup (n = 66) with N-terminal B-type natriuretic peptide <1800 (0.059, 0.004–0.979, and 0.019). There was no difference between the two groups for the duration of antibiotic use, major bleeding, or use of vasoactive drugs.

Conclusions

Chengqi decoction improved 28-day survival and reduced the prevalence of abdominal distension in patients with pneumonia-derived sepsis.

Antibiotic-Resistant Community-Acquired Bacterial Pneumonia

Antimicrobial resistance is a global concern, and prudent use of antibiotics is essential to preserve the current armamentarium of effective drugs. Acute respiratory tract infection is the most common reason for antibiotic prescription in adults. In particular, community-acquired pneumonia poses a significant health challenge and economic burden globally, especially in the current landscape of a dense and aging population. By updating the knowledge on the common antimicrobial-resistant pathogens in community-acquired respiratory tract infections, their prevalence, and resistance may pave the way to enhancing appropriate antibiotic use in the ambulatory and health care setting.

Isolation of ESBL-producing Bacteria from Sputum in Community-acquired Pneumonia or Healthcare-associated Pneumonia Does Not Indicate the Need for Antibiotics with Activity against This Class

Objective In the past decade, extended-spectrum β-lactamase (ESBL)-producing bacteria have increasingly frequently been isolated from various kinds of clinical specimens. However, the appropriate treatment of pneumonia in which ESBL-producing bacteria are isolated from sputum culture is poorly understood. To investigate whether or not ESBL-producing bacteria isolated from sputum in pneumonia cases should be treated as the causative bacteria. Methods and Patients In this retrospective study, we screened for patients, admitted between January 2009 and December 2015 in whom pneumonia was suspected and for whom sputum cultures yielded Escherichia coli or Klebsiella spp. isolates. We identified patients with community-acquired pneumonia (CAP) or healthcare-associated pneumonia (HCAP) from whom ESBL-producing bacteria had been isolated from sputum culture and to whom antibiotic treatment had been given with a diagnosis of pneumonia. We analyzed the patients' backgrounds and the effect of the antibiotic treatment for the initial 3-5 days. Results From 400 patients initially screened, 27 with ESBL-producing bacteria were secondarily screened. In this subset of patients, 15 were diagnosed with pneumonia, including 7 with CAP (5 E. coli and 2 K. pneumoniae) and 8 with HCAP (8 E. coli). These patients exhibited an average age of 84.1 years old, and 9 of 15 were men. No patients were initially treated with antimicrobials that are effective against isolated ESBL-producing bacteria. However, 13 of 15 patients showed improvement of pneumonia following the initial antibiotic treatment. Conclusion ESBL-producing bacteria isolated from sputum are not likely to be the actual causative organisms of pneumonia.

Regional differences in antibiotic-resistant pathogens in patients with pneumonia: Implications for clinicians

Antibiotic resistance is of great concern for both infection control and the treatment of infectious diseases. Previous studies reported that the occurrence of drug-resistant pathogens (DRPs)-for instance, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae-were associated with inappropriate antibiotic treatment that resulted in adverse outcomes. In addition, unnecessary use of broad-spectrum antibiotics for patients with non-DRPs increased mortality. Therefore, the assessment of risk for DRPs at diagnosis is critical to avoid patients' adverse events. In the present review, we discuss regional differences in the prevalence of DRPs, which ranged from 6% to 45%, in patients with community-onset pneumonia, including both community-acquired and healthcare-associated pneumonia. We then introduce the reported risk factors for DRPs in those patients, and present proposed prediction models for identifying patients with DRPs at diagnosis. Physicians should be aware that some of the risk factors for DRPs (e.g. prior antibiotic use and prior hospitalization) were common between regions; however, others may be different or the weighting of the risks may vary, even for the same risk factors. Therefore, a specific evaluation of risk factors for DRPs is recommended for each region and institution. Furthermore, we present a possible strategy for initial antibiotic selection in patients with community-onset pneumonia, considering DRPs risk. We also discuss future directions for the study of DRPs in community-onset, hospital-acquired and ventilator-associated pneumonia to improve the management of patients with pneumonia.

The respiratory threat posed by multidrug resistant Gram-negative bacteria

Respiratory infections are a major cause of global mortality and morbidity. In recent years, an increased incidence of multidrug-resistant (MDR) Gram-negative bacteria (GNB) has been described. Microorganisms such as Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae or Acinetobacter baumannii have been identified as causative pathogens of different respiratory tract infections. Several studies have detected MDR-GNB in patients with community-acquired and nosocomial pneumonia. Furthermore, MDR-GNB have also been isolated in patients with chronic obstructive pulmonary disease and bronchiectasis having acute or chronic bronchial infection. Prevalence varies depending on the geographical area but MDR-GNB has been reported in the Asia-Pacific region, Europe and the United States, reaching rates of 70% in hospital-acquired infection. The presence of MDR-GNB has been related to poor clinical outcomes, including increased mortality, although data regarding this relationship are limited. This is probably linked to inappropriate selection of empiric antibiotic treatment; this poses a threat of widespread resistance. GNB antibiotic resistance and the absence of new antibiotics are a major concern given limited treatment options; an aspect that deserves future research. We review current literature, highlight prevalence of MDR-GNB in different respiratory infections and explore their impact on clinical outcomes.

Empiric antibiotic selection and risk prediction of drug-resistant pathogens in community-onset pneumonia

PURPOSE OF REVEIW

Empiric antibiotic selection in community-onset pneumonia is complicated by uncertainty regarding risk of drug-resistant pathogens (DRPs). The healthcare-associated pneumonia (HCAP) criteria have limited predictive value and lead to unnecessary antibiotic use. Better methods of predicting risk of DRP and selecting empiric antibiotics are needed. Here we give an update on risk factors for DRP, available risk prediction models, and treatment strategy in patients with pneumonia.

RECENT FINDINGS

Evidence supporting factors that contribute to risk of DRP has improved since the advent of HCAP. Many of these risk factors have been reproducibly identified in heterogeneous populations. Newer methods of predicting DRP based on these factors demonstrate better performance than HCAP. Recent innovations include the potential to discriminate between risk for methicillin-resistant Staphylococcus aureus and other DRP, and use of severity as a modifier of treatment threshold. However, there is wide variation in included predictor variables, and at proposed thresholds most scores still favor overtreatment.

SUMMARY

Until reliable molecular diagnostics are available, additional development and validation of decision support models integrating local resistance rates, estimated DRP risk, severity, and threshold for anti-DRP antibiotics are needed. Once optimized models are identified, implementation studies will be needed to confirm safety and efficacy.

High morbidity and mortality of Clostridium difficile infection and its associations with ribotype 002 in Hong Kong

OBJECTIVES

We aim to study the disease burden, risk factors and severity of Clostridium difficile infection (CDI) in Hong Kong.

METHODS

We conducted a prospective, case-control study in three acute-care hospitals in Hong Kong. Adult inpatients who developed CDI diarrhoea confirmed by PCR (n = 139) were compared with the non-CDI controls (n = 114). Ribotyping of isolates and antimicrobial susceptibility testing were performed.

RESULTS

The estimated crude annual incidence of CDI was 23-33/100,000 population, and 133-207/100,000 population among those aged ≥65 years. The mean age of CDI patients was 71.5. Nursing home care, recent hospitalization, antibiotics exposure (adjusted OR 3.0, 95% CI 1.3-7.1) and proton-pump inhibitors use (adjusted OR 2.2, 95% CI 1.2-3.9) were risk factors. Severe CDI occurred in 41.7%. Overall mortality was 16.5% (among severe CDI, 26.5%). The commonest ribotypes were 002 (22.8%), 014 (14.1%), 012 and 046; ribotype 027 was absent. Ribotype 002 was associated with fluoroquinolone resistance and higher mortality (47.6% vs. 12.7%; adjusted HR 2.8, 95% CI 1.1-7.0).

CONCLUSIONS

Our findings show high morbidity and mortality of CDI in the older adults, and identify ribotype 002 as a possible virulent strain causing serious infections in this cohort.

Effect of age and residential status on the predictive performance of CURB-65 score

BACKGROUND

The CURB-65 score was designed to predict 30-day mortality and decide the site of care of pneumonia. It is uncertain how age and residential status affect the accuracy of CURB-65 score in older patients.

AIM

This study aimed to evaluate the effect of age and residential status on the performance of CURB-65 score in predicting 30-day all-cause mortality of pneumonia in older patients.

METHODS

We used combined data from two prospective observational cohorts of adult patients with pneumonia. Older patients aged ≥ 65 years were analysed.

RESULTS

Of 1644 patients, 1200 were living in the community and 464 residing in nursing homes. The 30-day mortality rates of community-acquired pneumonia (CAP) and nursing home-acquired pneumonia (NHAP) were 10.7% and 14.2% respectively. In each age group of CAP and NHAP, mortality increased with pneumonia severity. Mortality decreased with advancing age in NHAP, and the reverse was true for CAP. In NHAP but not CAP, the proportion of highly severe pneumonia (CURB-65 score ≥ 3) was lower in older patients. The overall predictive performance of CURB-65 score was comparable in CAP and NHAP. The accuracy deteriorated with advancing age in NHAP but not CAP. Using the cut-off score of ≥3 (highly severe pneumonia), the CURB-65 score achieved high negative predictive values (>90%) in CAP and NHAP.

CONCLUSIONS

Advancing age adversely affected the predictive performance of CURB-65 score in NHAP but not CAP. The score was not helpful in guiding the site of care at admission in older patients with pneumonia.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

A comparison of microbiology and demographics among patients with healthcare-associated, hospital-acquired, and ventilator-associated pneumonia: a retrospective analysis of 1184 patients from a large, international study

Background

Acceptance of healthcare-associated pneumonia (HCAP) as an entity and the associated risk of infection by potentially multidrug-resistant (MDR) organisms such as methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas and Acinetobacter have been debated. We therefore compared patients with HCAP, hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP) enrolled in a trial comparing linezolid with vancomycin for treatment of pneumonia.

Methods

The analysis included all patients who received study drug. HCAP was defined as pneumonia occurring < 48 hours into hospitalization and acquired in a long-term care, subacute, or intermediate health care facility; following recent hospitalization; or after chronic dialysis.

Results

Data from 1184 patients (HCAP = 199, HAP = 379, VAP = 606) were analyzed. Compared with HAP and VAP patients, those with HCAP were older, had slightly higher severity scores, and were more likely to have comorbidities. Pseudomonas aeruginosa was the most common gram-negative organism isolated in all pneumonia classes [HCAP, 22/199 (11.1%); HAP, 28/379 (7.4%); VAP, 57/606 (9.4%); p = 0.311]. Acinetobacter spp. were also found with similar frequencies across pneumonia groups. To address potential enrollment bias toward patients with MRSA pneumonia, we grouped patients by presence or absence of MRSA and found little difference in frequencies of Pseudomonas and Acinetobacter.

Conclusions

In this population of pneumonia patients, the frequencies of MDR gram-negative pathogens were similar among patients with HCAP, HAP, or VAP. Our data support inclusion of HCAP within nosocomial pneumonia guidelines and the recommendation that empiric antibiotic regimens for HCAP should be similar to those for HAP and VAP.