Comparison of pneumonia- and non-pneumonia-related Acinetobacter baumannii bacteremia: Impact on empiric therapy and antibiotic resistance

Infection toxicity assessment of tumor necrosis factor α inhibitors in the treatment of IBD: a real-world study based on the US food and drug administration adverse events reporting system (FAERS)

BACKGROUND

Tumor necrosis factor α (TNF-α) inhibitors are widely used to treat inflammatory bowel disease (IBD), but systematic risk assessment of infectious toxicity is still lacking.

RESEARCH DESIGN AND METHODS

We used disproportional analysis to calculate infection-related risk signals for four TNF-α inhibitors and compared them with infection-related signals for seven other therapies.

RESULTS

There were 55,379 reports of infection-related adverse events (AEs) with TNF-α inhibitors as a 'primary suspect (PS)' therapy. The median time to onset of infection-related AEs was 113 days (interquartile range [IQR] 14-612). TNF-α inhibitors present the strongest infectious toxic signal than interleukin 12/23 (IL-12/23) inhibitors, integrin blockers, Jak inhibitors, and S1P receptor modulator. Compared with infliximab, certolizumab pegol, and adalimumab, golimumab showed the strongest signal. The strongest signal corresponding to appendicitis, pulmonary tuberculosis, pneumonia, sepsis, urinary tract infection, otitis media and herpes zoster is golimumab, infliximab, golimumab, natalizumab, certolizumab pegol, infliximab, and infliximab.

CONCLUSIONS

Compared with other control therapies, TNF-α inhibitors have the strongest infectious toxicity signal. Compared with other TNF-α inhibitors, golimumab has the strongest infectious toxicity signal. When using TNF-α inhibitors to treat IBD, infection-related AEs should be vigilant.

Risk factors for bacteremic pneumonia and mortality (28-day mortality) in patients with Acinetobacter baumannii bacteremia

BACKGROUND

Patients infected with Acinetobacter baumannii (AB) bacteremia in hospital have high morbidity and mortality. We analyzed the clinical characteristics of pneumonia and nonpneumonia-related AB bloodstream infections (AB BSIs) and explored the possible independent risk factors for the incidence and prognosis of pneumonia-related AB BSIs.

METHODS

A retrospective monocentric observational study was performed. All 117 episodes of hospital-acquired AB bacteremia sorted into groups of pneumonia-related AB BSIs (n = 45) and nonpneumonia-related AB BSIs (n = 72) were eligible. Univariate/multivariate logistic regression analysis was used to explore the independent risk factors. The primary outcome was the antibiotic susceptibility in vitro of pneumonia-related AB BSIs group. The secondary outcome was the independent risk factor for the pneumonia-related AB BSIs group.

RESULTS

Among 117 patients with AB BSIs, the pneumonia-related group had a greater risk of multidrug resistant A. baumannii (MDRAB) infection (84.44%) and carbapenem-resistant A. baumannii (CRAB) infection (80%). Polymyxin, minocycline and amikacin had relatively high susceptibility rates (> 80%) in the nonpneumonia-related group. However, in the pneumonia-related group, only polymyxin had a drug susceptibility rate of over 80%. Univariate analysis showed that survival time (day), CRAB, MDRAB, length of hospital stay prior to culture, length of ICU stay prior to culture, immunocompromised status, antibiotics used prior to culture (n > = 3 types), endotracheal tube, fiberoptic bronchoscopy, PITT, SOFA and invasive interventions (n > = 3 types) were associated with pneumonia-related AB bacteremia. The multivariate logistic regression analysis revealed that recent surgery (within 1 mo) [P = 0.043; 0.306 (0.098-0.962)] and invasive interventions (n > = 3 types) [P = 0.021; 0.072 (0.008-0.671)] were independent risk factors related to pneumonia-related AB bacteremia. Multivariate logistic regression analysis revealed that length of ICU stay prior to culture [P = 0.009; 0.959 (0.930-0.990)] and recent surgery (within 1 mo) [P = 0.004; 0.260 (0.105-0.646)] were independent risk factors for mortality in patients with pneumonia-related AB bacteremia. The Kaplan‒Meier curve and the timing test showed that patients with pneumonia-related AB bacteremia had shorter survival time compared to those with nonpneumonia-related AB bacteremia.

CONCLUSIONS

Our study found that A. baumannii had a high rate of antibiotic resistance in vitro in the pneumonia-related bacteremia group, and was only sensitive to polymyxin. Recent surgery was a significantly independent predictor in patients with pneumonia-related AB bacteremia.

Clinical characteristics and prognosis of pneumonia-related bloodstream infections in the intensive care unit: a single-center retrospective study

Background

Bloodstream infections (BSI) are one of the most severe healthcare-associated infections in intensive care units (ICU). However, there are few studies on pneumonia-related BSI (PRBSI) in the ICU. This study aimed to investigate the clinical and prognostic characteristics of patients with PRBSI in the ICU and to provide a clinical basis for early clinical identification.

Methods

We retrospectively collected data from patients with bacterial BSI in a single-center ICU between January 1, 2017, and August 31, 2020. Clinical diagnosis combined with whole-genome sequencing (WGS) was used to clarify the diagnosis of PRBSI, and patients with PRBSI and non-PRBSI were analyzed for clinical features, prognosis, imaging presentation, and distribution of pathogenic microorganisms.

Results

Of the 2,240 patients admitted to the MICU, 120 with bacterial BSI were included in this study. Thirty-two (26.7%) patients were identified as having PRBSI based on the clinical diagnosis combined with WGS. Compared to patients without PRBSI, those with PRBSI had higher 28-day mortality (81.3 vs.51.1%, p = 0.003), a higher total mortality rate (93.8 vs. 64.8%, p = 0.002), longer duration of invasive mechanical ventilation (median 16 vs. 6 days, p = 0.037), and prolonged duration of ICU stay (median 21 vs. 10 days, p = 0.004). There were no differences in other baseline data between the two groups, but patients with PRBSI had extensive consolidation on chest radiographs and significantly higher Radiographic Assessment of Lung Edema scores (mean 35 vs. 24, p < 0.001). The most common causative organisms isolated in the PRBSI group were gram-negative bacteria (n = 31, 96.9%), with carbapenem-resistant gram-negative bacteria accounting for 68.8% (n = 22) and multidrug-resistant bacteria accounting for 81.3% (n = 26).

Conclusion

Pneumonia-related BSI is an important component of ICU-BSI and has a poor prognosis. Compared to non-PRBSI, patients with PRBSI do not have typical clinical features but have more severe lung consolidation lesions, and should be alerted to the possibility of their occurrence when combined with pulmonary gram-negative bacterial infections, especially carbapenem-resistant bacteria. Further multicenter, large-sample studies are needed to identify the risk factors for the development of PRBSI and prevention and treatment strategies.

Antibacterial Pathways in Transition Metal-Based Nanocomposites: A Mechanistic Overview

Across the planet, outbreaks of bacterial illnesses pose major health risks and raise concerns. Photodynamic, photothermal, and metal ion release effects of transition metal-based nanocomposites (TMNs) were recently shown to be highly effective in reducing bacterial resistance and upsurges in outbreaks. Surface plasmonic resonance, photonics, crystal structures, and optical properties of TMNs have been used to regulate metal ion release, produce oxidative stress, and generate heat for bactericidal applications. The superior properties of TMNs provide a chance to investigate and improve their antimicrobial actions, perhaps leading to therapeutic interventions. In this review, we discuss three alternative antibacterial strategies based on TMNs of photodynamic therapy, photothermal therapy, and metal ion release and their mechanistic actions. The scientific community has made significant efforts to address the safety, effectiveness, toxicity, and biocompatibility of these metallic nanostructures; significant achievements and trends have been highlighted in this review. The combination of therapies together has borne significant results to counter antimicrobial resistance (4-log reduction). These three antimicrobial pathways are separated into subcategories based on recent successes, highlighting potential needs and challenges in medical, environmental, and allied industries.

Haptoglobin-Conjugated Gold Nanoclusters as a Nanoantibiotic to Combat Bacteremia

Gold nanoclusters have revealed great potential as nanoantibiotics due to their superior chemical and physical characteristics. In this study, a peptide with 83 amino acids derived from haptoglobin was utilized as a surface ligand to synthesize gold nanoclusters via a facile hydrothermal approach. Characterization of the structural and optical properties demonstrated the successful synthesis of derived haptoglobin-conjugated gold nanoclusters. The spherical derived haptoglobin-conjugated gold nanoclusters exhibited a (111) plane of cubic gold and an ultra-small size of 3.6 ± 0.1 nm. The optical properties such as ultraviolet-visible absorption spectra, X-ray photoelectron spectroscopy spectra, fluorescence spectra, and Fourier transform infrared spectra also validated the successful conjugation between the derived haptoglobin peptide and the gold nanoclusters surface. The antibacterial activity, reactive oxygen species production, and antibacterial mechanisms of derived haptoglobin-conjugated gold nanoclusters were confirmed by culturing the bacterium Escherichia coli with hemoglobin to simulate bacteremia. The surface ligand of the derived haptoglobin peptide of derived haptoglobin-conjugated gold nanoclusters was able to conjugate with hemoglobin to inhibit the growth of Escherichia coli. The derived haptoglobin-conjugated gold nanoclusters with an ultra-small size also induced reactive oxygen species production, which resulted in the death of Escherichia coli. The superior antibacterial activity of derived haptoglobin-conjugated gold nanoclusters can be attributed to the synergistic effect of the surface ligand of the derived haptoglobin peptide and the ultra-small size. Our work demonstrated derived haptoglobin-conjugated gold nanoclusters as a promising nanoantibiotic for combating bacteremia.

Minocycline and the SPR741 Adjuvant Are an Efficacious Antibacterial Combination for Acinetobacter baumannii Infections

Antibiotic resistance, when it comes to bacterial infections, is not a problem that is going to disappear anytime soon. With the lack of larger investment in novel antibiotic research and the ever-growing increase of resistant isolates amongst the ESKAPEE pathogens (Enterobacter cloacae, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterococcus sp., and Escherichia coli), it is inevitable that more and more infections caused by extensively drug-resistant (XDR) and pandrug-resistant (PDR) strains will arise. One strategy to counteract the growing threat is to use antibiotic adjuvants, a drug class that on its own lacks significant antibiotic activity, but when mixed with another antibiotic, can potentiate increased killing of bacteria. Antibiotic adjuvants have various mechanisms of action, but polymyxins and polymyxin-like molecules can disrupt the Gram-negative outer membrane and allow other drugs better penetration into the bacterial periplasm and cytoplasm. Previously, we showed that SPR741 had this adjuvant effect with regard to rifampin; however, rifampin is often not used clinically because of easily acquired resistance. To find additional, appropriate clinical partners for SPR741 with respect to pulmonary and wound infections, we investigated tetracyclines and found a previously undocumented synergy with minocycline in vitro and in vivo in murine models of infection.

Comparison of pneumonia- and non-pneumonia-related Acinetobacter baumannii complex bacteremia: A single-center retrospective study

BACKGROUND

Acinetobacter baumannii complex (ABC) is a group of increasingly prevalent opportunistic pathogens that cause a variety of life-threatening nosocomial infections, especially in the intensive care unit (ICU). This study assessed the differences between pneumonia- and non-pneumonia-related ABC bacteremia and possible independent risk factors for 30-day mortality.

METHODS

The clinical data of ICU patients diagnosed with ABC bacteremia at a tertiary care hospital from January 2009 to December 2020 were collected, and sorted into groups of ABC bacteremia with and without pneumonia.

RESULTS

Significant changes in the incidence of ABC bacteremia and antibiotic resistance were observed over the 12-year study. Compared with nonpneumonia-related ABC bacteremia, pneumonia-related ABC bacteremia was associated with a higher rate of hypertension, less prior tigecycline use, more carbapenem-resistant (CR) strains, and a higher 30-day mortality rate. In multivariate analysis, immunosuppression, higher APACHE II score, and SOFA score were independent risk factors for 30-day mortality. Moreover, the risk of death was 1.919 times higher in the pneumonia-related group.

CONCLUSIONS

Although pneumonia-related ABC bacteremia had worse outcomes, it was not an independent risk factor for death statistically. Immunosuppression and disease severity levels increased the risks of death in ICU patients with ABC bacteremia.

High-Dose versus Standard-Dose Tigecycline Treatment of Secondary Bloodstream Infections Caused by Extensively Drug-Resistant Acinetobacter baumannii: An Observational Cohort Study

Background

Extensively drug-resistant Acinetobacter baumannii (XDR-AB) infections have become difficult to treat and are associated with a high mortality rate. Tigecycline is one of the most effective agents used to treat XDR-AB infections, but data from treating bloodstream infection (BSI) in standard dose do not look promising, because of its low plasma concentration. Secondary BSI with primary infection source may indicate tigecycline treatment with a higher dose. Currently, little is known about the application of high-dose tigecycline among patients with secondary BSI caused by XDR-AB. We aimed to investigate the outcomes for high-dose (HD) tigecycline treatment versus standard-dose (SD) treatment of these patients.

Methods

An observational cohort study was conducted at four university affiliated hospitals in mainland China. Adult inpatients who were confirmed as having secondary BSI caused by XDR-AB and received definitive tigecycline treatment were consecutively included. Patients who were treated with 50 mg every 12 h were defined as the SD group, and a twice dose was defined as the HD group.

Results

Of the enrolled patients, 63 received SD and 88 received HD tigecycline treatment. Patients in the two groups had similar with regard to baseline clinical conditions. The 30-day survival was affected by the source of the primary infection. Survival was significantly better in patients with non-pulmonary-infection-related BSI than in patients with pulmonary-infection-related BSI. Multivariate Cox regression confirmed that HD had a protective effect only observed in patients with non-pneumonia-related BSI.

Conclusion

A tigecycline dose that is twice its standard dose is better for the treatment of XDR-AB infection only in BSI associated with non-pulmonary infection.

Emerging Trends in Nanomaterials for Antibacterial Applications

Around the globe, surges of bacterial diseases are causing serious health threats and related concerns. Recently, the metal ion release and photodynamic and photothermal effects of nanomaterials were demonstrated to have substantial efficiency in eliminating resistance and surges of bacteria. Nanomaterials with characteristics such as surface plasmonic resonance, photocatalysis, structural complexities, and optical features have been utilized to control metal ion release, generate reactive oxygen species, and produce heat for antibacterial applications. The superior characteristics of nanomaterials present an opportunity to explore and enhance their antibacterial activities leading to clinical applications. In this review, we comprehensively list three different antibacterial mechanisms of metal ion release, photodynamic therapy, and photothermal therapy based on nanomaterials. These three different antibacterial mechanisms are divided into their respective subgroups in accordance with recent achievements, showcasing prospective challenges and opportunities in clinical, environmental, and related fields.

Ten-Year Changes in Bloodstream Infection With Acinetobacter Baumannii Complex in Intensive Care Units in Eastern China: A Retrospective Cohort Study

Background: There is little evidence on the changing prevalence, microbiological profile, and outcome of nosocomial Acinetobacter baumannii complex (ABC)-caused bloodstream infection (ABCBSI) specified in intensive care units (ICUs) in long-term studies, especially in China. Objective: We aimed to investigate changes in incidence, antibiotic resistance, therapy, and prognosis of ABCBSI in ICUs in eastern China during 2009-2018. Methods: A multicenter retrospective cohort study was conducted, and microbiological and clinical data for patients with ABCBSI acquired in nine adult ICUs in eastern China from 2009 to 2018. Results: A total of 202 cases were enrolled. For the years 2009-2010, 2011-2012, 2013-2014, 2015-2016, and 2017-2018, the incidence of ABCBSI increased significantly, as did the percentage of pan-drug-resistant isolates and resistant rates to most of antimicrobial agents; the percentage of drug-sensitive isolates decreased (all P < 0.05). The frequency of treatment with carbapenems and tigecycline increased, and that of cephalosporins decreased. Compared with those in the first years (2009-2012), ABCBSI patients in the lattermost years (2017-2018) were less often treated with appropriate empirical therapy, more often underwent pneumonia-related ABCBSI and mechanical ventilation support, and had higher 28-day mortality rates. Multivariate Cox regression indicated that increase in the degree of ABC antibiotics resistance, pneumonia-related ABCBSI, and septic shock were risk factors of 28-day mortality and associated with significant lower survival days. Conclusions: The past decade has witnessed a marked increase in the incidence of ABCBSI and in antibiotic resistance, with increasing pneumonia-related infections and worrisome mortality in ICUs in China. Controlling increasing resistance and preventing nosocomial pneumonia may play important roles in combatting these infections.

Survival of carbapenem-resistant Acinetobacter baumannii bacteremia: colistin monotherapy versus colistin plus meropenem

Objective

The aim of this study was to compare clinical outcomes between patients with carbapenem-resistant Acinetobacter baumannii (CRAB) bacteremia treated with colistin monotherapy and those treated with colistin plus meropenem.

Methods

We retrospectively evaluated data from 71 patients with CRAB bacteremia treated from November 2006 to February 2018. Predictors of 14-day mortality were determined through logistic regression analysis.

Results

Our study cohort included 40 bacteremia patients (44.6 %) treated with colistin monotherapy and 31 (55.4 %) treated with colistin plus meropenem. Overall 14-day mortality tended to be higher with monotherapy rather than combination therapy (47.5% vs 25.8%). The latter also showed a tendency for higher clinical success rate compared with monotherapy (61.3% vs 40.0%). Logistic regression analysis showed that Pitt bacteremia score, pneumonia, and combination therapy were significantly associated with mortality. In patients with higher Pitt bacteremia score (≥4), mortality was significantly higher with monotherapy compared with combination therapy (66.7% vs 27.8%). In patients with lower Pitt bacteremia score (≤3), mortality was similar between the two treatment groups (26.3% vs 23.1%).

Conclusion

Treatment with colistin plus meropenem improves survival in critically-ill patients with CRAB.

Etiology and characteristics of community-acquired pneumonia in an influenza epidemic period

PURPOSE

The etiology of community-acquired pneumonia (CAP) in hospital patients is often ambiguous due to the limited pathogen detection. Lack of a microbiological diagnosis impairs precision treatment in CAP.

METHODS

Specimens collected from the lower respiratory tract of 195 CAP patients, viruses were measured by the Single-plex real-time PCR assay and the conventional culture method was exploited for bacteria.

RESULTS

Among the 195 patients, there were 46 (23.59%) pure bacterial infections, 20 (10.26%) yeast infections, 32 (16.41%) pure viral infections, 8 (4.10%) viral-yeast co-infections, and 17 (8.72%) viral-bacterial co-infections. The two most abundant bacteria were Acinetobacter baumannii and klebsiella pneumoniae, whereas the most common virus was influenza A.

CONCLUSIONS

Non-influenza respiratory microorganisms frequently co-circulated during the epidemic peaks of influenza, which easily being ignored in CAP therapy. In patients with bacterial and viral co-infections, identifying the etiologic agent is crucial for patient's therapy.

Identification and characterization of capsule depolymerase Dpo48 from Acinetobacter baumannii phage IME200

Background

The emergence of multidrug- or extensively drug-resistant Acinetobacter baumannii has made it difficult to treat and control infections caused by this bacterium. It is urgently necessary to search for alternatives to conventional antibiotics for control of severe A. baumannii infections. In recent years, bacteriophages and their derivatives, such as depolymerases, showed great potential as antibacterial or antivirulence agents against bacterial infections. Nonetheless, unlike broad-spectrum bactericidal antibiotics, phage-encoded depolymerase targets only a limited number of bacterial strains. Therefore, identification of novel depolymerases and evaluation of their ability to control A. baumannii infections is important.

Methods

A bacteriophage was isolated from hospital sewage using an extensively drug-resistant A. baumannii strain as the host bacterium, and the phage’s plaque morphology and genomic composition were studied. A polysaccharide depolymerase (Dpo48) was expressed and identified, and the effects of pH and temperature on its activity were determined. Besides, a serum killing assay was conducted, and amino acid sequences homologous to those of putative polysaccharide depolymerases were compared.

Results

Phage IME200 yielded clear plaques surrounded by enlarged halos, with polysaccharide depolymerase activity against the host bacterium. A tail fiber protein with a Pectate_lyase_3 domain was identified as Dpo48 and characterized . Dpo48 was found to degrade the capsule polysaccharide of the bacterial surface, as revealed by Alcian blue staining. Dpo48 manifested stable activity over a broad range of pH (5.0–9.0) and temperatures (20–70 °C). Results from in vitro serum killing assays indicated that 50% serum was sufficient to cause a five log reduction of overnight enzyme-treated bacteria, with serum complement playing an important role in these killing assays. Moreover, Dpo48 had a spectrum of activity exactly the same as its parental phage IME200, which was active against 10 out of 41 A. baumannii strains. Amino acid sequence alignment showed that the putative tail fiber proteins had a relatively short, highly conserved domain in their N-terminal sequences, but their amino acid sequences containing pectate lyase domains, found in the C-terminal regions, were highly diverse.

Conclusions

Phage-encoded capsule depolymerases may become promising antivirulence agents for preventing and controlling A. baumannii infections.

Multidrug-resistance Acinetobacter baumannii pneumonia in a rheumatoid arthritis patient receiving tumor necrosis factor inhibitor: A case report

INTRODUCTION

Multidrug-resistant Acinetobacter baumannii (MDRAB) pneumonia with severe sepsis in a patient with rheumatoid arthritis (RA), who is predisposed after treatment with tumor necrosis factor inhibitor (TNFI), is a rare severe infection and can be successfully treated with prompt antibiotics.

CASE PRESENTATION

A 75-year-old woman was diagnosed with RA >30 years previously. After inadequate treatment responses to conventional disease-modifying antirheumatic drugs (DMARDs), she developed progressive RA, including swollen joints in both hands, and had a high disease activity score of 4.96 when presenting at our rheumatology clinic. She had started taking the TNFI, golimumab (50 mg/month), 3 years before and developed a productive cough 4 weeks before this admission. One week after admission, she developed fever, dyspnea, hypoxemia, tachycardia, and increased serum C-reactive protein level.

DIAGNOSIS

Chest plain film (CxR) and computed tomography of the chest showed hospital-acquired pneumonia; microbial examination of the sputum showed the presence of MDRAB.

THERAPEUTICS

She was prescribed a full course of antibiotics with cefoperazone sulbactam.

OUTCOMES

CxR showed complete remission of pneumonia.

CONCLUSION

Biological DMARDs, such as TNFI, act as a double-edged sword: these drugs are used to treat autoimmune diseases, but they increase the risk of infection. The trend toward antibiotic resistance and persistent environmental survival of MDRAB is an emerging problem in countries with high rates of antibiotic abuse. TNFI may affect intestinal immunity by inducing dysbiosis, which affects T helper 17-mediated mucosal immunity and can contribute to A baumannii colonization and the development of MDRAB in frequently hospitalized patients.

Septic shock from descending necrotizing mediastinitis - combined treatment with IgM-enriched immunoglobulin preparation and direct polymyxin B hemoperfusion: a case report

BACKGROUND

Descending necrotizing mediastinitis is a common and progressive polymicrobial infection involving the neck and chest with a high death rate (10 to 40%). From a microbiological point of view, descending necrotizing mediastinitis is sustained by Gram-positive bacteria (43-62%), anaerobes (46-78%), and, rarely, Gram-negative bacteria. Data collected during the Antibiotic Resistance-Istituto Superiore di Sanità project confirmed that Italy is positioned among the countries with the highest levels of resistance in most pathogenic species under surveillance. In particular, 32.9% of Klebsiella pneumoniae isolates were resistant to carbapenem, 33.6% of Staphylococcus aureus to methicillin, and 28.7% and 43.9% of Escherichia coli isolates to third-generation cephalosporins and fluoroquinolones, respectively.

CASE PRESENTATION

We describe the case of a 38-year-old white man with septic shock due to descending necrotizing mediastinitis sustained by multidrug-resistant Gram-negative and Gram-positive bacteria treated after surgery with an IgM-enriched immunoglobulin preparation and polymyxin B hemoperfusion therapy.

CONCLUSION

Despite the contrasting data on the use of immunoglobulins and polymyxin B hemoperfusion in septic shock and the lack of literature in cases of acute mediastinitis caused by both Gram-negative and Gram-positive multidrug-resistant bacteria, we obtained an improvement in clinical conditions and the survival of our patient, against all odds.

Bacteremic and non-bacteremic pneumonia caused by Acinetobacter baumannii in ICUs of South China: A Clinical and Microbiological Study

Acinetobacter baumannii has been a dreadful problem for ICU physicians for a long time. Bacteremic pneumonia (BP) caused by this organism has a higher mortality compared to other organisms. Between 2012 and 2015, 86 BP and 89 non-bacteremic pneumonia (NBP) patients from five ICUs were enrolled into the study. The 7-day and 14-day mortality rates were higher in BP patients than in NBP patients (P < 0.001). Procalcitonin elevation, high APACHEII score and recent surgery, were independently associated with BP episodes. Acute respiratory distress syndrome, coma, high APACHEII score and procalcitonin elevation, were independently associated with mortality in the BP group. Extensively drug-resistant isolates were detected in 34.9% of BP and 25.8% of NBP isolates. PFGE identified 12 and 9 genotypes in the BP and NBP isolates, respectively, with 6 genotypes shared by both groups. ST195 was the most prevalent type (40%), followed by ST457 (18.9%). The pandemic clonal complex 92 was predominant, accounting for 94.3% of the strains. For all studied periods, mortality remained higher in the BP than the NBP group. Disease severity was the main risk factor for high mortality in the BP group, and other factors related to mortality were infection, and not treatment or microbiology-related.

Biofilm-Related Genes: Analyses in Multi-Antibiotic Resistant Acinetobacter Baumannii Isolates From Mainland China

BACKGROUND Acinetobacter baumannii is an important nosocomial pathogen which shows a high level of mortality risk. Several papers have reported biofilm formation as a well-known pathogenic mechanism in A. baumannii infections and exceptional antibiotic resistance. The study aims to explore the potential relationships between biofilm-related genes and antimicrobial resistance. MATERIAL AND METHODS Samples from 122 patients with lower respiratory tract infections of A. baumannii were collected at Fujian Longyan First Hospital from January 2013 to September 2014. A. baumannii was isolated from sputum specimens. Biofilm-related genes including abaI, csuE, ompA, and bla-PER1 were analyzed by PCR. The minimum inhibitory concentration method was used to determine the sensitivity of each strain to antibiotics. RESULTS The clinical manifestations of A. baumannii-induced lower respiratory tract infections lacked specificity. Infected patients were most commonly admitted to intensive care units (54.9%) and frequently had chronic obstructive pulmonary disease (27.0%). The detection rates of abaI and csuE were both 59.8%, and those of ompA and bla-PER1 were 100% and 0%, respectively. After genetic testing, antimicrobial resistance to amikacin, ampicillin/sulbactam, and 14 other types of antimicrobials was higher in abaI- and csuE-positive strains than in abaI- and csuE-negative strains (P<0.05). CONCLUSIONS The findings of our study suggest that abaI- and csuE-positive Acinetobacter baumannii strains are associated with a higher incidence of antibiotic resistance in 14 types of antimicrobials.