Resistance Rate Of Acinetobacter Baumannii Research Articles

Assessment of the pattern of antibiotic resistance among microorganisms isolated from the culture medium prepared from hospitalized patients: A retrospective study

ABSTRACT Background: Antibiotic resistance has become quite a challenge in the treatment of bacterial infections in the world. Therefore, the present study was conducted with the aim of investigating the pattern of antibiotic resistance among microorganisms isolated from the culture medium prepared from hospitalized patients. Methods: The type of study was cross-sectional descriptive. The antibiotic resistance pattern of positive samples collected from patients who got hospitalized in Shahid Faghihi hospital of Shiraz University of Medical Sciences between 2020 and 2021 using the disc diffusion method according to CLSI standards was measured. Then the data were entered into SPSS version 22 software and analyzed with appropriate statistical tests. Results: Of all positive samples, 69.7% were Gram-negative and the rest were Gram-positive. The most frequent Gram-negative bacteria were Acinetobacter baumannii (31.4%), Escherichia coli (25.3), and Klebsiella pneumonia (21.2%), and the most frequent Gram-positive bacteria were Staphylococcus aureus (79%), Coagulase-negative staphylococci (15.4%), and Enterococcus (3.6%). The resistance rate of Acinetobacter baumannii, Klebsiella pneumonia, and Pseudomonas aeroginosa against ciprofloxacin was 91.4%, 74.3%, and 52.3%; the resistance rate against gentamicin was 90.5%, 54.3%, and 43.9%; the resistance rate against Piperacillin-Tazobactam was 85.6%, 65%, and 43.1%; the resistance rate against imipenem was 97.1%, 57.9%, and 65.4%; and the resistance rate against colostin was 1.9%, 0%, and 3.4%, respectively. The resistance rate of Staphylococcus aureus against cefoxotin and vancomycin was 42.7% and 2.8%, respectively. Conclusion: Finally, we concluded from this study that microorganisms isolated from patients have developed resistance to many commonly used antibiotics.

Strategically reducing carbapenem-resistant Acinetobacter baumannii through PDCA cycle-driven antibiotic management

PurposeWith the escalating global challenge of antibiotic resistance, particularly the resistance rate of Acinetobacter baumannii, the need to rationalize carbapenem antibiotic use in clinical settings has become paramount. Our study tapped into a fishbone diagram to uncover the irrationalities in applying these antibiotics and highlight potential influencing factors. MethodsBased on these analyses, we initiated targeted intervention strategies. A PDCA cycle-based scientific management approach was implemented through the combined efforts of our antimicrobial stewardship team and relevant departments. ResultsOur study showed a significant post-intervention increase in the rational use of carbapenem antibiotics (P < 0.01) and a concurrent decrease in the detection of carbapenem-resistant Acinetobacter baumannii. ConclusionOur findings underscore that carbapenem usage can be effectively minimized with the continuous refinements offered by the PDCA cycle, leading to a reduction in multidrug-resistant bacteria, thus fostering rational drug use in healthcare.

Acinetobacter baumannii infection in intensive care unit: analysis of distribution and drug resistance.

The isolation rate and drug resistance rate of Acinetobacter baumannii (A.baumannii) have increased over the years, which has become one of the main causes of infection and death in intensive care unit (ICU) patients. Analysis of the distribution characteristics, drug resistance and influencing factors of A.baumannii in ICU could provide basis and reference for the infection prevention and clinical treatment. In this study, patients diagnosed with A.baumannii infection in ICU from January 2020 to December 2021 were selected. Samples of patients were collected for bacterial culture, drug sensitivity test analysis and drug resistant gene detection of A.baumannii. A total of 197 strains of A.baumannii were cultured in 2021, which was 18 strains more than in 2020. The specimens were mainly from lower respiratory tract secretions, and the isolated strains were multi-drug resistant. The resistance of isolates to tobramycin, gentamicin, and trimethoprim-sulfamethoxazole in 2021 showed a significant increase compared to 2020, while there were no significant differences observed in other resistance changes. The prevalence of multi-drug resistant A.baumannii in ICU remains high. Among them, all imipenem-resistant A.baumannii strains carried OXA-23 gene. Clinical treatment should use antibiotics reasonably based on the characteristics of bacterial resistance, and strengthen the prevention and control of hospital infection, pay more attention to the disinfection and isolation to reduce the risk of cross infection.

Analysis of blood culture data at a university hospital: bacterial distribution and cumulative antimicrobial resistance (2016–2020)

Background: The distribution of bacteria isolated from bloodstream infections and cumulative antimicrobial susceptibility data are the basis for empirical decisions regarding antibiotics as an initial treatment. Therefore, it is important to consistently collect blood culture results of individual patients and analyze them correctly. Methods: The blood culture results of patients at Gachon University Gil Medical Center from 2016 to 2020 were analyzed retrospectively to determine the bacterial distributions and antibiotic resistance patterns. Duplicates were eliminated by including only the first isolate of each species per patient. Results: Escherichia coli (27.1%) was the most commonly isolated bacterium from blood cultures, followed by Klebsiella pneumoniae (10.1%) and Staphylococcus aureus (8.6%). The methicillin resistance rate of S. aureus was 49.2%, and the vancomycin resistance rate of Enterococcus faecium was 39.5%; with no significant changes over the study period. The cefotaxime, ciprofloxacin, and ertapenem resistance rates of E. coli were 35.0%, 46.8%, and 0.7%, respectively. Seventeen carbapenem-resistant E. coli strains were isolated, of which 11 produced carbapenemase. The cefotaxime, ciprofloxacin, and ertapenem resistance rates of K. pneumoniae were 29.5%, 31.7%, and 5.4%, respectively. Forty-eight carbapenem-resistant K. pneumoniae strains were isolated, of which 37 produced carbapenemase. The imipenem resistance rates of Acinetobacter baumannii and Pseudomonas aeruginosa were 72.3% and 23.4%, respectively. Conclusion: In the blood culture results from 2016 to 2020, the isolation frequency of E. coli, K. pneumoniae, and E. faecium showed an increasing trend, whereas that of S. aureus was stable. Over the 5 year study period, the ciprofloxacin resistance rate of E. coli and P. aeruginosa and ampicillin/sulbactam resistance rate of A. baumannii significantly increased.

Analysis on Distribution and Drug Resistance of Pathogenic Bacteria in ICU Patients with Nosocomial Infection from 2019 to 2021

Objective: To understand the pathogenic bacteria isolated from patients and their drug resistance changes in general ICU of the Affiliated Hospital of Hebei University, so as to provide reference for appropriate selection of antibiotics in clinical practice. Methods: A retrospective investigation was conducted to analyze the bacteriological distribution and drug resistance of nosocomial pathogens isolated from the specimens of hospitalized patients in the comprehensive ICU of the hospital from 2019 to 2021. The US technology BD Phoenix 100 automatic bacterial identification analyzer was used for bacterial identification of the pathogen samples, disk diffusion method was used for drug susceptibility test, and SPSS 22.0 software was used to analyze the trend of drug resistance. Results: A total of 970 strains of nosocomial pathogens were detected in the three years. The main pathogens were Acinetobacter baumannii (133 strains, 13.71%), Klebsiella pneumoniae (106 strains, 10.93%), Pseudomonas aeruginosa (83 strains, 8.56%), Escherichia coli (76 strains, 7.84%) and Enterococcus faecium (69 strains, 7.11%). The resistance rate of Acinetobacter baumannii to antibiotics was high. Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli had low resistance rates to carbapenems. The situation of bacterial drug resistance is still serious. Conclusion: The drug resistance of pathogenic bacteria collected from Class III Grade A Hospital’s patients to antibiotics was generally high. Therefore, clinical departments should strengthen the inspection of specimens of infection and drug sensitivity test in order to grasp the resistance mechanisms and drug resistance of pathogenic bacteria changes, and select appropriate antimicrobial agents according to the test results. Besides, the formation of drug-resistant strains also needs to be prevented, and the treatment of patients with severe infection needs to be improved.

Trends and Correlation Between Antimicrobial Resistance and Antibiotics Consumption in a Specialist Children's Hospital from 2016 to 2021.

PurposeTo explore the trends and correlation between antibiotics consumption and antimicrobial resistance in children in a specialist hospital from 2016–2021 in China.Patients and MethodsThis retrospective study investigated data on the consumption of antibiotics and antimicrobial resistance in children. Antibiotics consumption was expressed as defined daily doses (DDDs)/1000 patient-days based on the Guidelines for Anatomical Therapeutic Chemical. The trends in antibiotics consumption and antimicrobial resistance rates were analyzed by linear regression, while Spearman correlation analysis was employed to evaluate their correlations.ResultsAn increasing trend in the annual consumption of carbapenems and monobactams was detected (all P<0.05). A significant upward trend was detected in the annual resistance rates of Enterococcus faecium to ciprofloxacin, Streptococcus pneumonia to ceftriaxone, Acinetobacter baumannii to carbapenems, Enterobacter cloacae to carbapenems, Pseudomonas aeruginosa to ceftazidime, and Escherichia coli to cefepime, while the annual resistance rates of Escherichia coli to carbapenems had a significant downward trend (all P<0.05). The consumption of cephalosporin/β-lactamase inhibitor (C/BLI) combinations and carbapenems had significant positive correlations with the resistance rates of Acinetobacter baumannii to carbapenems (r=0.763, P<0.001; r=0.806, P<0.001), Enterobacter cloacae to carbapenems (r=0.675, P<0.001; r=0.417, P=0.043), and Pseudomonas aeruginosa to ceftazidime (r=0.625, P=0.001; r=0.753, P<0.001), respectively. Also, increasing consumption of monobactams was related to the upward resistance rates of Acinetobacter baumannii to carbapenems (r=0.557, P=0.005) and Enterobacter cloacae to carbapenems (r=0.507, P= 0.011).ConclusionThis study demonstrated significant positive associations between antibiotics consumption and specific antimicrobial resistance rates. The current findings pointed out some directions to pursue in controlling the prevalence of certain resistant bacterial strains in children.

Anti-Acinetobacter baumannii single-chain variable fragments show direct bactericidal activity.

Objective(s):The high resistance rate of Acinetobacter baumannii and the limited number of available antibiotics have prompted a worldwide effort to develop effective antimicrobial agents. Accordingly, identifying single-chain variable fragment antibodies (scFvs), capable of exerting direct antibacterial activity in an immune system-independent manner, may be making immunocompromised patients more susceptible to A. baumannii infections.Materials and Methods:To isolate bactericidal scFvs targeting A. baumannii, we panned a large human scFv phage display library against whole-cell extensively drug-resistant (XDR) A. baumannii strains grown as biofilm or cultured with human blood or human peripheral blood mononuclear cells plus plasma. The binding of scFv-phages to A. baumannii was assessed by the dot-blot assay. Soluble scFvs, derived from the selected phages, were assessed based on their ability to bind and inhibit the growth of A. baumannii. Results: Five phage clones showed the highest reactivity toward A. baumannii. Among five soluble scFvs, derived from positive phage clones, two scFvs, EB211 and EB279, had high expression yields and displayed strong binding to A. baumannii compared with the controls. Moreover, XDR A. baumannii strains treated with positively-charged scFvs, including EB211, EB279, or a cocktail of EB211 and EB279 (200 µg/ml), displayed lower viability (approximately 50%, 78%, and 40% viability, respectively) compared with PBS-treated bacteria.Conclusion:These results suggest that combining last-resort antibiotics with bactericidal scFvs could provide promising outcomes in immunocompromised individuals with A. baumannii infections.

Risk Factors for Multidrug-Resistant Organisms Infection in Diabetic Foot Ulcer.

ObjectiveThe aim of this study is to analyze the microbiological characteristics of diabetic foot ulcer (DFU) and drug resistance of multidrug-resistant organisms (MDROs) and to reveal the potential risk factors for MDROs. This provides a basis for early empiric antibiotic treatment.MethodsThis study included 348 patients with diabetic foot ulcer in Chu Hsien-I Memorial Hospital & Metabolic Disease Hospital of Tianjin Medical University between May 2020 and November 2021. A total of 475 strains of bacteria were cultured, among which 240 strains were multidrug-resistant bacteria, accounting for 51%. Binary logistic regression was used to analyze risk factors. First, univariate analysis was used to calculate the p value of variables, and then multivariate analysis was conducted for variables with p < 0.1 to analyze independent risk factors. Risk factors with p < 0.05 in multivariable analysis were considered as independent risk factors. The strength of the association was represented by odds ratio and 95% confidence interval.ResultsUnivariable logistic regression analysis demonstrated that previous hospitalization, previous antibiotic therapy, ulcer size >4cm2, surgical therapy, D-dimer, and CRP were associated with MDRO infection in patients with DFU. Multivariate logistic regression analysis demonstrated that previous hospitalization (OR = 1.91; 95% CI = 1.11–3.28; p = 0.02), ulcer size >4cm2 (OR = 1.68; 95% CI = 1.03–2.76; p = 0.04), surgical therapy (OR = 2.14; 95% CI = 1.03–4.47; p = 0.04), and CRP (OR = 1.01; 95% CI = 1.00–1.01; p = 0.03) were independent risk factors for MDROs infection in diabetic foot patients. Drug resistance analysis may indicate that the proportion and drug resistance rate of Acinetobacter baumannii in Tianjin, China, have changed.ConclusionPrevious hospitalization, ulcer size >4cm2, surgical therapy and CRP were independent risk factors for MDROs infection in diabetic foot patients. Identifying these risk factors can help us identify the high-risk patients of diabetic foot with MDRO infection early. More attention to high-risk patients and more aggressive isolation precautions may reduce the incidence of MDRO infection in diabetic foot patients.

Comparison of Drug Resistance of Bile Isolated Bacteria in Nanjing from 2017 to 2020

Background: Analyzed pathogenic bacteria isolated from bile samples of patients with biliary tract infection and their drug resistance in the first Affiliated Hospital of Nanjing Medical University from 2017 to 2020, so as to provide evidence for the treatment of biliary tract infection. Methods: Clinical strains isolated from bile specimens of patients suspected of biliary infection in the First Affiliated Hospital of Nanjing Medical University from 2017 to 2020 were collected, The drug susceptibility criteria are based on the standards published by the National Standardization Committee of the US Clinical Laboratories. WHONET 5.6 software was used to analyze the distribution of pathogens and drug resistance. Results: From January 2017 to December 2020, a total of 2006 strains of bile pathogenic bacteria were cultured and identified. There were 1253 cases of gram-negative bacilli, 638 cases of gram-positive cocci, 98 cases of fungi, and 17 cases of Gram-positive bacilli. The top five pathogens of Gram negative bacilli were Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter baumannii. The top five pathogens of gram positive cocci were Enterococcus faecium, Enterococcus faecalis, Enterococcus gallinarum, Enterococcus faecalis and Staphylococcus epidermidis. the resistance rate of Escherichia coli to ampicillin, ampicillin / sulbactam, cefotetan, ceftazidime, ceftriaxone,cefepime, itronam, compound trimethoprim decreased, the resistance rate of Klebsiella pneumoniae to gentamicin, levofloxacin decreased, the resistance rate of Enterobacter cloacae to ciprofloxacin, levofloxacin decreased. the resistance rate of Pseudomonas aeruginosa to ceftazidime, cefepime, gentamicin decreased. the resistance rate of Acinetobacter baumannii to ceftazidime, ciprofloxacin decreased. the resistance rate of Enterococcus faecium to penicillin G, high concentration streptomycin, erythromycin decreased. Conclusions: Enterogenic pathogens were the main pathogens in China. Such as Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis and Enterococcus faecalis; Nosocomial infection pathogens. For example, Pseudomonas aeruginosa and Acinetobacter also need to be paid attention to. Clinicians should improve their awareness of microbiological examination and provide more reliable pathogenic evidence for the selection of clinical antibiotic.

In Vitro Activity of Various Sulbactam Compounds and Piperacillin/Tazobactam against Clinical Isolates of Different Gram-Negative Bacteria.

To provide direction for clinical application and pharmaceutical exploitation, the in vitro activity of sulbactam compounds and PIP/TAZ 8 : 1 against clinical isolates of Gram-negative bacteria (GNB, n = 976) was evaluated according to Clinical and Laboratory Standards Institute (CLSI) 2019. By minimal inhibitory concentrations (MICs), the resistance rate of all GNB to AMP/SBT 2 : 1 (56.9-100%) was significantly higher than other drugs, except the resistance rate of Acinetobacter baumannii (Aba, n = 204) to piperacillin/tazobactam (PIP/TAZ 8 : 1, 78.4%) which was close to it (76.5%). Additionally, the resistance rate of Aba to other compounds except AMP/SBT 2 : 1 differed greatly, but that of Klebsiella pneumonia (Kpn, n = 205) varied rarely. In addition, Escherichia coli (Eco, n = 204) and Kpn demonstrated low and high resistance rates, respectively. Compared with cefoperazone/sulbactam (CPZ/SBT 2 : 1), PIP/TAZ 8 : 1 had advantage in anti-Eco (RR = 0.5and OR = 2.17) and anti-Kpn activity (RR = 0.88and OR = 1.27), while its activity against Pseudomonas aeruginosa (Pae: n = 194, RR = 0.91, and OR = 1.12), Aba (RR = 1.31 and OR = 0.41), and other Enterobacteriaceae (other Ebc: n = 169, RR = 1.40, and OR = 0.62) was not better than CPZ/SBT 2 : 1. Although it had advantage against Eco (RR = 0.60 and OR = 1.78), Pae (RR = 0.67 and OR = 1.63), and Aba (RR = 0.70 and OR = 2.05), the inhibition effect of piperacillin/sulbactam (PIP/SBT 2 : 1) against Kpn (RR = 0.94 and OR = 1.12) and other Ebc was just similar with CPZ/SBT 2 : 1 (RR = 0.93 and OR = 1.10). Furthermore, the anti-Eco (RR = 0.70 and OR = 1.50), anti-Kpn (RR = 0.89 and OR = 1.24), and anti-Pae (RR = 0.74 and OR = 1.46) activities of ceftazidime/sulbactam (CAZ/SBT 1 : 1) had a weak advantage, while its activity against Aba (RR = 0.94 and OR = 1.15) and other Ebc (RR = 0.79 and OR = 1.36) was just close to CPZ/SBT 2 : 1. Moreover, the inhibitory effect of PIP/SBT 1 : 1 against all tested clinical species was more active than CPZ/SBT 2 : 1, while that of CAZ/SBT 2 : 1 against all species of bacteria analyzed was weaker than the controls.

Analysis of Nosocomial Infection and Risk Factors in Patients with ECMO Treatment.

ObjectiveTo investigate the drug resistance of nosocomial infection-related pathogens in patients who underwent extracorporeal membrane oxygenation (ECMO), analyzing the nosocomial infection-related risk factors.MethodsThe medical records of 56 patients who received ECMO support treatment in the First Affiliated Hospital with Nanjing Medical University from January 2013 to December 2019 were selected. The nosocomial infection, pathogen distribution and drug resistance, and the influencing factors of nosocomial infection were analyzed. The predictive value of independent risk factors for nosocomial infection after ECMO was analyzed using the receiver operating characteristic (ROC) curve.ResultsA total of 56 patients receiving ECMO treatment were included. The nosocomial infection rate was 28.57%, and the prevalence infection rate was 44.64%. Lower respiratory tract infection was the main infection site. Among these infectious patients, 53 strains of pathogens were detected. The results showed that the gram-negative bacteria were mainly Acinetobacter baumannii and Klebsiella pneumonia. Moreover, the drug resistance rate of Acinetobacter baumannii to most of the antibiotics was more than 65%, among which the drug resistance rate to carbapenems was 80%. The results of risk factors of nosocomial infection after ECMO were analyzed by univariate analysis, showing that ECMO treatment time, hospitalization time, antibacterial drug use time, ventilator use time, catheter intubation time and central venous intubation time were statistically significant (all p < 0.001). Multivariate analysis identified that ECMO treatment time was an independent risk factor. As showed by ROC curve, ECMO treatment time had a high predictive value for postoperative nosocomial infection. ECMO treatment times of more than 4.5 days were associated with an increased risk of nosocomial infection.ConclusionThe nosocomial infection rate after ECMO was relatively high, and the main pathogens are Gram-negative bacteria. The selection of antibiotics should be based on the results of pathogen drug sensitivity.

Antimicrobial Stewardship Programs: A Review

Antimicrobial resistance is a global crisis which requires urgent action to halt its spread. The rate of deaths due to antibiotic resistance from bacterial infection reached 25,000 annually. Resistance rates to Escherichia coli and Klebsiella pneumoniae has risen to reach 40% and 56% respectively, in addition to high resistance rates of Acinetobacter baumannii to fluroquinolones and other antibiotics that reached 56%. So it has become an urgent need to establish robust programs to control antibiotic resistance and optimize the use of antibiotics in hospitals. In Egypt particularly, the rate of antibiotic resistance becomes high due to wrong traditions of dispensing and administration antibiotics in hospitals and pharmacies, all that drove us to build a program controlling all these obstacles. Antimicrobial stewardship programs (ASPs) are strategic programs to prevent development of microbial resistance and monitor prescription patterns of clinicians inside hospitals. In addition to minimize the toxic effects, overuse of antibiotics and improve the patient health, and minimize the emergence of antibiotic resistance in shadow of the lack of development of novel antimicrobial agents. In this review, we aimed to discuss antimicrobial stewardship programs, their core elements, clinical importance, essential requirements and their implementation in Egypt. In conclusion, the development of national guidelines for antimicrobial stewardship programs would be a useful step to help clinicians in making evidence-based treatment choices regarding antibiotic therapy and implementation of better antibiotic during pandemics. We hope this review help the medical staff to perform stewardship programs to control the antibiotic resistance in Egypt healthcare settings.

Analysis of distribution and drug resistance of Acinetobacter baumannii infection in neurosurgery

Objective To analyze the distribution and drug resistance of Acinetobacter baumannii infection in neurosurgical care unit, and to provide basis for rational control of nosocomial infection and use of antibiotics. Methods The infection distribution and drug resistance of 150 Acinetobacter baumannii strains isolated from blood, sputum, cerebrospinal fluid and surgical wound sites in the neurosurgical care unit of the 11th Clinical College of Shanxi Medical University from January 2018 to December 2020 were analyzed retrospectively. Results The infection rate of Acinetobacter baumannii was 74.16% in respiratory tract, 15.00% in intracranial and 13.40% in surgical wound in the neurosurgical care unit. The drug resistance rate of Acinetobacter baumannii to amtronem was the highest (90.00%), followed by piperacillin (88.10%), polymyxin E was the lowest (2.38%), followed by ampicillin/sulbactam (57.14%). Conclusion Acinetobacter baumannii infection is mainly distributed in the lower respiratory tract, intracranial and surgical wounds in neurosurgical care units, and the drug resistance rate of Acinetobacter baumannii to aminotronem and piperacillin is high. Clinical application of antibiotics should be rational, and the types and doses of antibiotics need to be adjusted dynamically in order to further strengthen the control of nosocomial infection.

Pathogens' distribution and changes of antimicrobial resistance in the bile of acute biliary tract infection patients

Objective: To investigate the pathogens' distribution and antimicrobial resistance in the bile of acute biliary tract infection patients. Methods: The data of bile bacterial culture and drug sensitivity test of 223 acute biliary tract infection patients who underwent gallbladder puncture or endoscopic retrograde cholangiopancreatography drainage from July 2009 to July 2019 were analyzed retrospectively at Department of General Surgery,Xinhua Hospital,Affiliated to Shanghai Jiao Tong University School of Medicine.There were 141 males and 82 females with age of 67.3 years(range:28 to 93 years).Three to five milliliter of bile was extracted from each patient and sent to the laboratory for bacterial culture,identification and drug sensitivity test.The patients were divided into two groups according to the visiting time: the former group (n=124) was admitted from July 2009 to July 2014,and the latter group(n=99) was admitted from August 2014 to July 2019.The distribution of pathogenic bacteria and the changing trend of drug resistance rate of common bacteria in the two groups were compared.The results of drug sensitivity test were analyzed by WHONET software provided by WHO bacterial surveillance network.The drug resistance rates in different time periods were compared by χ2 test. Results: In this study,there were 147 cases of acute cholangitis and 76 cases of acute cholecystitis.A total of 376 strains of pathogenic bacteria were cultured.Among them,98 strains(26.1%) were gram-positive bacteria,269 strains(71.5%) were gram-negative bacteria and 9 strains(2.4%) were fungi.The top three gram-positive bacteria were Enterococcus faecium (49.0%,48/98),Enterococcus faecalis(20.4%,20/98),and Enterococcus luteus(7.1%,7/98).The top 5 gram-negative bacteria were Escherichia coli(33.5%,90/269),Klebsiella pneumoniae(13.8%,37/269),Pseudomonas aeruginosa(13.0%,35/269),Acinetobacter baumannii (12.6%,34/269),and Enterobacter cloacae(4.8%,13/269).From 2009 to 2019,there was no significant change in the proportion of gram-positive bacteria (former group vs. latter group: 25.3% vs. 28.2%) and gram-negative bacteria(former group vs.latter group: 74.7% vs. 71.8%) in the bile of patients with acute biliary tract infection.Gram-positive bacteria were mainly Enterococci(85.7%,84/98) and gram-negative bacteria were Escherichia coli(33.5%,90/269).Acinetobacter baumannii accounted for 7.8%(11/142) of gram-negative bacteria in the former group and 18.1%(23/127) in the latter group,an increase of 10.3% over previous five years.Pseudomonas aeruginosa had a downward trend,16.9% in the former group(24/142) and 8.7% in the latter group (11/127),the proportion decreased by 8.2%,and the other changes were not significant.The drug resistance rates of common gram-positive bacteria were relatively stable,and the drug resistance rates of Enterococcus faecium to many antibiotics were higher than those of Enterococcus faecalis.The resistance rates of gram-negative bacteria to most antibiotics showed an upward trend,among which Klebsiella pneumoniae showed an upward trend to most of antibiotics(former group: 0/15－4/13, latter group: 55.0%－70.0%; χ2=3.996－16.942, P=0.000－0.046).The drug resistance rates of Acinetobacter baumannii was generally higher,but there were no significant changes in the drug resistance rates of Acinetobacter baumannii between the two groups.The drug resistance rates of Pseudomonas aeruginosa to most antibiotics increased,and the overall drug resistance rates of Escherichia coli were stable and showed a slight upward trend. Conclusions: The main pathogens in bile of patients with acute biliary tract infection are gram-negative bacteria.The constituent ratio of various gram-negative bacteria had no significant change from 2009 to 2019,but the drug resistance rates shows an upward trend.Among the gram-negative bacteria, Escherichia coli is the most important pathogen,and the proportion has no significant change.The proportion of Acinetobacter baumannii in the former group was significantly higher than that in the former group.And the proportion of Pseudomonas aeruginosa has a decreased trend.

Antimicrobial Peptide Cec4 Eradicates the Bacteria of Clinical Carbapenem-Resistant Acinetobacter baumannii Biofilm.

The drug resistance rate of Acinetobacter baumannii increases year on year, and the drugs available for the treatment of carbapenem-resistant A. baumannii (CRAB) infection are extremely limited. A. baumannii, which forms biofilms, protects itself by secreting substrates such as exopolysaccharides, allowing it to survive under adverse conditions and increasing drug resistance. Antimicrobial peptides are small molecular peptides with broad-spectrum antibacterial activity and immunomodulatory function. Previous studies have shown that the antimicrobial peptide Cec4 has a strong effect on A. baumannii, but the antibacterial and biofilm inhibition of this antimicrobial peptide on clinical carbapenem resistance A. baumannii is not thoroughly understood. In this study, it was indicated that most of the 200 strains of CRAB were susceptible to Cec4 with a MIC of 4 μg/ml. Cec4 has a strong inhibitory and eradication effect on the CRAB biofilm; the minimum biofilm inhibition concentration (MBIC) was 64–128 μg/ml, and the minimum biofilm eradication concentration (MBEC) was 256–512 μg/ml. It was observed that Cec4 disrupted the structure of the biofilm using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). A comparative transcriptome analysis of the effects of the antimicrobial peptide Cec4 on CRAB biofilm, identified 185 differentially expressed genes, including membrane proteins, bacterial resistance genes, and pilus-related genes. The results show that multiple metabolic pathways, two-component regulation systems, quorum sensing, and antibiotic synthesis-related pathways in A. baumannii biofilms were affected after Cec4 treatment. In conclusion, Cec4 may represent a new choice for the prevention and treatment of clinical infections, and may also provide a theoretical basis for the development of antimicrobial peptide drugs.

Analysis of distribution and drug resistance of pathogens isolated from 159 patients with catheter-related bloodstream infection in burn intensive care unit

Objective: To analyze the distribution and drug resistance of pathogens isolated from patients with catheter-related bloodstream infection (CRBSI) in burn intensive care unit (BICU). Methods: From January 2011 to December 2018, among 2 264 patients who were peripherally inserted central venous catheter at the BICU of the First Affiliated Hospital of Army Medical University (the third Military Medical University), hereinafter referred to as the author's unit, 159 patients were diagnosed CRBSI, including 131 males and 28 females, aged 43 (1, 79) years. The pathogens primarily isolated from peripheral venous blood and central venous catheter blood/anterior central venous catheter specimen of patients with CRBSI were retrospectively analyzed. API bacteria identification kits and automatic microorganism identification instrument were used to identify pathogens. Broth micro-dilution method or Kirby-Bauer paper disk diffusion method was used to detect the drug resistance of the pathogens to 5 antifungal drugs including fluconazole and itraconazole, etc., and 37 antibacterial drugs including tigecycline and imipenem, etc. Modified Hodge test was used to further identify imipenem- and meropenem-resistant Klebsiella pneumonia. D test was used to detect erythromycin-induced clindamycin resistant Staphylococcus aureus. The WHONET 5.6 software was applied to analyze the annual incidence of CRBSI, mortality of patients with CRBSI, incidence of CRBSI cases, distribution of infection site, and duration of catheterization, detection of Gram-negative and Gram-positive bacteria, fungi, methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-sensitive Staphylococcus aureus (MSSA), and drug resistance of fungi and major Gram-negative and Gram-positive bacteria to the commonly used antibiotics in clinic. Results: (1) The incidence of CRBSI was 7.0% (159/2 264) during the eight years, which was slightly higher in 2014 and 2017 with 13.6% (30/221) and 11.1% (24/217) respectively. The mortality rate of patients with CRBSI was 7.5% (12/159). (2) The incidence of CRBSI cases was 14.9% (338/2 264); the main infection site was femoral vein, totally 271 cases (80.2%), and the duration of catheterization of this site was 9 (2, 25) d. (3) During the eight years, totally 543 strains of pathogens were isolated, including 353 (65.0%) strains of Gram-negative bacteria, 140 (25.8%) strains of Gram-positive bacteria, and 50 (9.2%) strains of fungi. The top three isolated pathogens with isolation rate from high to low were Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa, accounting for 23.2% (126/543), 17.1% (93/543), and 15.7% (85/543), respectively. Fungi were mainly Candida parapsilosis. Among the Staphylococcus aureus, the detection rate of MRSA was 98.9% (92/93), and that of MSSA was 1.1% (1/93). (4) Except for the low drug resistance rates to polymyxin B, minocycline, and tigecycline, the drug resistance rates of Acinetobacter baumannii to the other antibiotics were considerably high (80.1%-100.0%). Pseudomonas aeruginosa was not resistant to polymyxin B but highly resistant to netilmicin (88.7%) and piperacillin (92.6%), with resistance rates to the other antibiotics from 34.5% to 62.7%. Klebsiella pneumoniae was not resistant to tigecycline and lowly resistant to imipenem and meropenem (28.9%, 9 imipenem- and meropenem-resistant strains were further confirmed by modified Hodge test), with resistance rates to the other antibiotics from 40.9% to 95.2%. The resistance rates of MRSA to most antibiotics were higher than those of MSSA. MRSA was not resistant to linezolid, vancomycin, teicoplanin, sulfamethoxazole, or tigecycline. The resistance rates of MRSA to clindamycin and erythromycin were 7.9% and 62.0%, respectively, and those to the other antibiotics were higher than 91.5%. Except for the complete resistance to penicillin G and tetracycline, MSSA was not resistant to the other antibiotics. Thirty-three strains of Staphylococcus aureus showed resistance to erythromycin-induced clindamycin. Fungi was not resistant to amphotericin B, with drug resistance rates to voriconazole, itraconazole, ketoconazole, and fluconazole from 4.2% to 6.2%. Conclusions: The incidence of CRBSI and mortality of patients with CRBSI are high in BICU of the author's unit, and the main infection site is femoral vein. There are various types of pathogens in patients with CRBSI, and most of them are Gram-negative. The top three isolated pathogens are Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa, accompanying with grim drug resistance phenomenon.

Characteristics and Drug Resistance of Pathogens in Urinary Tract Infection Patients Complicated with Urinary Calculi

Main objective is to explore the characteristics, drug resistance, and risk factors of pathogens in urinary tract infection patients complicated with urinary calculi. A total of 417 patients with urinary calculi who were treated in our hospital from January 2017 to December 2019 were enrolled in this study, including 234 patients with urinary tract infection and 183 patients without urinary tract infection. The midstream urine of 234 patients with urinary tract infection were cultured and used in the drug sensitivity test. Univariate and multivariate logistic regression analysis was used to analyze the risk factors of postoperative urinary tract infection in patients with urinary calculi. A total of 624 strains of pathogens were isolated from the urine samples of 234 patients with postoperative urinary tract infection, of which 386 strains were gram-negative bacteria (61.86 %), 169 strains were gram-positive bacteria (27.08 %), and 69 strains were fungus (11.06 %). In the drug resistance test, the resistance rates of Staphylococcus aureus to tetracycline, rifampicin, and levofloxacin, and the resistance rate of Enterococcus faecium to levofloxacin was low. Enterococcus faecalis had the lowest resistance rate to levofloxacin, followed by azithromycin and gentamicin. The resistance rates of Staphylococcus epidermidis to levofloxacin and vancomycin were low and the resistance rate to erythromycin was 100.00 %. The resistance rate of Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis to meropenem and amikacin, and the resistance rate of Klebsiella pneumoniae and Proteus mirabilis to etilmicin and ceftriaxone were low. Univariate analysis showed that the postoperative urinary tract infection in patients with urinary calculi was related to the age, operation time, postoperative indwelling catheter time, stone size, and preoperative prophylactic use of antibiotics. Multivariate logistic regression analysis showed that the age (≥65 y old), operation time (≥60 min), postoperative indwelling catheter time (≥7 d), and no preoperative prophylactic use of antibiotics were the risk factors of postoperative urinary tract infection in patients with urinary calculi. Patients with urinary calculi were prone to urinary tract infection after the operation. The main pathogens of infection were gram-negative bacteria and gram-positive bacteria, and they were resistant to some antibiotics. Antibiotics should be treated reasonably according to the risk factors of urinary tract infection and the results of the drug sensitivity tests to avoid further aggravation of bacterial drug resistances.

Analysis of drug resistance and homology of 226 Acinetobacter baumannii in geriatric department

Objective Through statistical analysis of drug resistance and homology of Acinetobacter baumannii in geriatric department of our hospital, we can provide evidence for clinical experience in antibiotics use and nosocomial infection control. Methods The drug resistance of Acinetobacter baumannii isolated from the elderly rehabilitation department in Ningbo Kangning Hospital from January 2017 to December 2018 was analyzed by retrospective analysis.The homology of Acinetobacter baumannii isolated from clinical isolates was detected by PCR ERIC-PCR method and agarose gel electrophoresis method. Results The resistance rates of Acinetobacter baumannii to ciprofloxacin and levofloxacin were 41.6% and 35.4%, respectively.The resistance rates to cefepime, ceftriaxone and ceftazidime were 40.3%, 38.9% and 36.7%, respectively.The resistance rate to imipenem was 38.9%, and the sensitivity rates to cefoperazone/sulbactam, gentamicin and tobramycin were all over 70%.A total of 226 strains of Acinetobacter baumannii were genotyped by ERIC-PCR.They were mainly classified into A, B, C, D and E 5 types.Among them, 116 strains were type A, 68 strains were type B, 26 strains were type C, 8 strains were type D and E. Conclusion The resistance rate of Acinetobacter baumannii to some antibiotics in geriatric rehabilitation department is still at a high level, so we should continue to strengthen the rational use of antibiotics; at the same time, the strains are highly homologous, and there is likely to be clonal transmission in the department, so we should take more effective measures to prevent and control its transmission in hospital. Key words: Acinetobacter baumannii; Drug resistance; Seguence homology; Geriatric department

Epidemiological characteristics of non-fermentative bacteria causing bloodstream infection in Sichuan: a retrospective multicenter study

Objective To retrospectively analyze the distribution of non-fermentative bacteria causing bloodstream infection in hospitalized patients in Sichuan Province and their drug susceptibility to common antibiotics for better understanding their epidemiological characteristics. Methods From January 1, 2015 to December 31, 2017, all of the non-fermentative bacteria isolated from patients with bloodstream infection in nine hospitals in Sichuan Province were collected. Species distribution and drug resistance test results were retrospectively analyzed. Results A total of 6 291 strains of pathogenic bacteria were isolated, including 3 674 strains of gram-negative bacteria (58.4%) and 2 617 strains of gram-positive bacteria (41.6%). The gram-positive bacteria were 1 895 strains of Staphylococcus (30.1%), 372 strains of Streptococcus (5.9%), 317 strains of Enterococcus (5.1%) and 33 strains of other gram-positive bacteria (0.5%). The gram-negative bacteria were 3 191 Enterobacteriaceae strains (50.7%), 389 non-fermentative strains (6.2%) and 94 other gram-negative strains (1.5%). The isolated non-fermentative bacteria were mainly Pseudomonas aeruginosa (136 strains, 35.0%), Acinetobacter baumannii (126 strains, 32.0%) and Stenotrophomonas maltophilia (33 strains, 8.5%). There were 167 (42.9%), 112 (28.8%) and 82 (21.1%) non-fermentative bacteria isolated in internal medicine departments, ICUs and surgery departments, respectively. The drug resistance rates of Pseudomonas aeruginosa to cefepime, ciprofloxacin and gentamicin were 16.5%, 10.7% and 9.9%, respectively. Carbapenems-resistant Pseudomonas aeruginosa (CR-PA) accounted for 13.6%. No polymyxin-resistant Pseudomonas aeruginosa was found. The resistance rates of Acinetobacter baumannii to all antibiotics were over 30% except for minocycline and polymyxin and 75.7% of carbapenem-resistant Acinetobacter baumannii (CR-AB) were isolated. The drug resistance rates to levofloxacin, trimethoprim/sulfamethoxazole and ceftazidime were 0%, 0% and 37.0% in Stenotrophomonas maltophilia isolates and 10.5%, 4.2% and 19% in Burkholderia cepacia isolates, respectively. Conclusions Non-fermentative bacteria causing 6.2% of bloodstream infection in Sichuan, mainly by Pseudomonas aeruginosa and Acinetobacter baumannii. There were significant differences in the isolation rate of non-fermentative bacteria in different departments and most of the strains were isolated in internal medicine departments. The detection rate of Acinetobacter baumannii with multiple drug resistance was high, while other non-fermentative bacteria had good sensitivity to antibiotics. Key words: Blood culture; Multicenter; Non-fermentative bacteria

Time series analysis of antibacterial usage and bacterial resistance in China: observations from a tertiary hospital from 2014 to 2018.

PurposeTo describe trends and correlation between antibacterial exposure and bacterial resistance from hospitalized patients in a hospital in southern China.Patients and methodsThis study used hospital-wide data regarding antimicrobial resistance and consumption between January 1, 2014 and December 31, 2018. Antibacterial consumption was expressed as antimicrobial use density (AUD). The changes in trends and associations between antibacterial utilization and resistance were analyzed using linear regression and time series analysis.ResultsThe total AUD of all antimicrobials decreased year by year (50.66 in 2014 vs 44.28 in 2018, P=0.03). The annual use of antimicrobials, such as penicillins, monobactams, aminoglycosides, macrolides, and lincosamides, significantly decreased (P<0.05), while the annual use of quinolones and tetracyclines significantly increased (P<0.05). Among the top ten isolated bacteria, antimicrobial resistance trends of Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Staphylococcus aureus, and Staphylococcus epidermidis significantly decreased (P<0.05). Significant positive correlation was found between AUD of carbapenems and resistance rate of Acinetobacter baumannii to imipenem (β=32.87, P<0.01), as well as the correlation between AUD of quinolones and resistance rate of Enterococcus faecium to levofloxacin (β=104.40, P<0.01).ConclusionThe consumption of antibiotics and antibiotic resistance has been significantly improved in this tertiary hospital. Additionally, the efforts of China’s antibiotic management may be suggested by the relationship between indicated antibiotic resistance and consumption. However, overall AUD levels and poor control of the use of antibiotics, such as quinolones and tetracyclines, still require strengthened management.