Structure of VanH from Acinetobacter baumannii reveals domain dynamics and provides a platform for Anti-resistance drug design.

Structure and Dynamics of the ATP-Bound Open Conformation of Hsp70 Chaperones

Variations on the ABC

Surveillance of multidrug resistant uropathogenic bacteria in hospitalized patients in Indian

Objective To explore the multi-drug resistance condition and independent risk factors of Acinetobacter baumannii infection in patients after liver transplantation. Methods Clinical data of 257 patients who underwent liver transplantation in Shanghai General Hospital between January 2010 and June 2015 were retrospectively analyzed. The informed consents of all patients were obtained and the local ethical committee approval was received. Twenty-five patients were infected with multi-drug resistant Acinetobacter baumannii. Among the patients, 17 were males and 8 were females, 10 were younger than 50 years old and 15 were older or equal to 50 years old. Drug sensitive test was detected using concentration gradient method, metallo-beta-lactamase was detected using composite paper, and bacterial genotype was detected using repetitive sequence polymerase chain reaction (PCR) and gel electrophoresis. Drug resistance, drug-resistant spectrum, genotype distribution, infection time and influence factors of infection for multi-drug resistant Acinetobacter baumannii were observed and analyzed. Single-factor analysis of multi-drug resistant Acinetobacter baumannii was conducted using Chi-square test and multiple-factor analysis was conducted using logistic regression analysis. Results The incidence of multi-drug resistant Acinetobacter baumannii infection was 9.7%(25/257). Acinetobacter baumannii strains were highly resistant to aminoglycosides, quinolones, penicillins, cephalosporins and carbapenems, with the drug resistance of 100%. In addition, 96%(24/25) of the strains were metallo-beta-lactamase positive. Three genotypes were observed in the 25 strains of Acinetobacter baumannii: type B (n=18), type A (n=5) and type C (n=2). Positive postoperative fungal culture (OR=5.470, 95%CI: 1.402-21.333, P<0.05) and re-intubation (OR=11.538, 95%CI: 2.228-59.742, P<0.05) were the independent risk factors for multi-drug resistant Acinetobacter baumannii infection. Conclusions The incidence of multidrug-resistant Acinetobacter baumannii infection in patients after liver transplantation is high. Multidrug-resistant Acinetobacter baumannii is highly resistant to multiple antibiotics, and type B is the main genetype. Positive postoperative fungal culture and re-intubation are the independent risk factors for multi-drug resistant Acinetobacter baumannii infection. Key words: Liver transplantation; Multidrug resistance-associated proteins; Acinetobacter baumannii; Infection

Objective To investigate antimicrobial resistance of clinical isolates from 15 hospitals submitted to Guangzhou Surveillance of Antimicrobial Resistance (GSAR) in 2007,and to learn the feature of bacterial resistance in Guangzhou.Methods Disc diffusion test (K-B methods) was employed to study the antimicrobial resistance.Results Of 18 500 clinical isolates,Gram negative bacilli and Gram positive cocci accounted for 68.4% and 31.6%,respectively,and 45.7% isolates in Gram negative bacilli belonged to non-fermentative bacilli.The detection rotes of methiciHin-resistant strains was 55.9% in Staphylococcus aureus and 75.9% in coagulase negative Staphylococcus.All of the Staphylococcus pneumoniae isolates were penicillin-susceptible (PSSP) according to 2008 CLSI criterion.One strains of Enterobacter faecium were identified as vancomycin-resistance (VRE).The resistant rates of Enterobacter to imipenem and merpenem were the lowest.The prevalence of ESBLs-producing strains in Enterobacter coli and Klebsiella spp.isolates was 43.8% and 39.8%,respectively.Against all the ESBLs strains in Enterobacter coli and Klebsiella spp,meropenem,imipenem,cefoperazone/sulbactam,and piperacillin/tazobactam showed the lowest resistant rates,ranging from 0 to 14.1%,20.4%,24.4% and 25.4% isolates of Pseudomonas aernginosa were resistant to efoperazone/sulbactam,piperacillin/tazobactam and meropenem,while 75.6%,72.4% and 63.2% isolates of Pseudomonas aeruginosa were susceptible to piperacillin/tazobactam,meropenem and cefoperazone/sulbactam,respectively.The resistance rates of Acinetobacter spp.to cefoperazone/sulbactam and meropenem were 2.6% and 5.1%,respectively.Some panresistant isolates of Pseudomonas aeruginosa (5.5%) and Ac/naobacter baumannii (1.5%) emerged.The resistance of Pseudomonas aeruginosa and Aeinetobacter baumannii isolated from sputum sample was higher than those from blood sample.Conclusions The increase of isolated rates of non-fermentative Gram-negative bacilli and the emerging bacterial resistance and oandrug resistance in Pseudomonas aeruginosa and Acinetobacter baumannii warrants further enbancing the local surveillance of bacterial resistance and characterization of panresistance mechanism to inform the rational use of anfimicrobial agents and containment of bacterial resistance. Key words: Bacterial resistance; Anfimicrobial agent; Bacterial susceptibility testing

Structural Basis of J Cochaperone Binding and Regulation of Hsp70

PurposeThis study aimed at identifying the main antimicrobial resistance of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli) pathogens in a Romanian infectious diseases hospital. This antimicrobial resistance is a global threat, having high rates of multidrug resistance and limited treatment options.Patients and MethodsThis retrospective study (2016–2020) assessed the antimicrobial resistance of ESKAPE pathogens isolated from the patient’s biological samples. The microbiological diagnosis was performed by classical culture methods. The antimicrobial susceptibility analysis used the Kirby–Bauer disk-diffusion method and the method of minimum inhibiting concentration with the automated Vitek, according to the CLSI (Clinical and Laboratory Standards Institute) standards.ResultsIncluded in this study were 4293 bacterial isolates: 67% Gram-negative bacilli, 31% Gram-positive cocci and 2% other morphotinctorial bacteria. ESKAPE pathogens were found in 97% of the bacterial isolates strains; E. coli (38.26%) and Staphylococcus aureus (26%) were the most prevalent. Most bacterial strains were isolated from urine cultures (45.6%), skin and soft tissue secretions/collections (35.9%) and also blood cultures (4.2%). Increased antimicrobial resistance was observed for methicillin-resistant Staphylococcus aureus (MRSA)s, extended spectrum beta-lactamase producing (ESBL) Enterobacterales, carbapenem-resistant (CR) Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. No vancomycin resistance was found for Enterococcus faecium. The highest prevalence rates of multidrug resistance were found in methicillin-resistant Staphylococcus aureus (86.6%), Acinetobacter baumannii (36.8%), Pseudomonas aeruginosa (29.1%) and Klebsiella pneumoniae (24.4%).ConclusionESKAPE pathogens are frequently isolated in the infectious diseases hospital, with main antimicrobial resistance: ESBL, MRSA and CR. The local antimicrobial resistance pattern is essential in updating the local protocols and for appropriately prescribing antibiotics. Streamlining microbiological diagnosis and aligning with the European standards for antimicrobial susceptibility testing are necessary steps in harmonizing the regional network for good antimicrobial resistance control practices.

Background: The aim of this study was to assess the drivers of multidrug-resistant (MDR) bacterial infection development in coronavirus disease 2019 (COVID-19) and its impact on patient outcome. Methods: Retrospective analysis on data from 32 consecutive patients with COVID-19, admitted to our intensive care unit (ICU) from March to May 2020. Outcomes considered were MDR infection and ICU mortality. Results: Fifty percent of patients developed an MDR infection during ICU stay after a median time of 8 [4-11] days. Most common MDR pathogens were carbapenem-resistant Klebsiella pneumoniae and Acinetobacter baumannii, causing bloodstream infections and pneumonia. MDR infections were linked to a higher length of ICU stay (p = 0.002), steroid therapy (p = 0.011), and associated with a lower ICU mortality (odds ratio: 0.439, 95% confidence interval: 0.251-0.763; p < 0.001). Low-dose aspirin intake was associated with both MDR infection (p = 0.043) and survival (p = 0.015). Among MDR patients, mortality was related with piperacillin-tazobactam use (p = 0.035) and an earlier onset of MDR infection (p = 0.042). Conclusions: MDR infections were a common complication in critically ill COVID-19 patients at our center. MDR risk was higher among those dwelling longer in the ICU and receiving steroids. However, MDR infections were not associated with a worse outcome.

Allostery in Hsp70 Chaperones Is Transduced by Subdomain Rotations

To analyze the detection, drug resistance, and status of infection of Acinetobacter baumannii (AB) in burn ICU during 3 years. A total of 2 010 specimens of wound secretion, blood, venous catheter attachment, sputum, stool and urine were collected from 505 burn patients hospitalized in our burn ICU from January 2011 to December 2013, and bacterial culture was performed. Pathogens were identified by automatic microorganism identifying and drug sensitivity analyzer. Drug resistance of all the obtained AB to 16 antibiotics commonly used in clinic, including cefoperazone/sulbactam, polymyxin, etc., was tested with K-B paper disk diffusion method. Patients with AB infection were ascertained. The WHONET 5.6 software was used to analyze the distribution of pathogens during 3 years, the isolation of AB with different sources and the status of drug resistance of AB to 16 antibiotics each year, and the status of patients with AB infection, and their outcome. A total of 961 strains of pathogens were isolated, among which 185 (19.25%) strains were Gram positive cocci, 728 (75.75%) strains were Gram negative bacilli, and 48 (4.99%) strains were fungi. A total of 172 strains of AB were isolated, ranking the second place among all the detected pathogens, with 67 (38.95%) strains from wound secretion, 11 (6.40%) strains from blood, 23 (13.37%) strains from venous catheter attachment, and 71 (41.28%) strains from sputum, no AB strain was isolated from feces or urine. The AB strains were found sensitive to polymyxin and with relatively low drug resistance rate to minocycline, while the drug resistance rates were over 80.0% to the other 14 antibiotics commonly used in clinic in 2013. AB culture of wound secretion was positive in 27 patients. Among them, 7 patients suffered from wound infection, and the wound infection was caused by AB in 1 out of the 7 patients. AB culture of blood was positive in 7 patients. Among them, 3 patients suffered from bloodstream infection, and the infection was due to AB invasion in 1 out of the 3 patients. AB culture of venous catheter attachment was positive in 20 patients. Among them, 8 patients suffered from bloodstream infection, and the infection was due to AB invasion in 1 out of the 8 patients. AB culture of sputum was positive in 35 patients. Among them, 13 patients suffered from ventilatory associated pneumonia, and 2 out of the 13 patients were diagnosed as AB infection. A total of 69 patients were AB culture positive, among them 64 patients were cured, 2 patients were transferred to other hospitals, and 3 patients died, with the mortality rate of 4.35%. AB in our burn ICU has a high detection rate and extensive drug resistance in above-mentioned 3 years. However, AB was mainly colonized in patients with extensive burns with a low mortality rate.

NMR Investigations of Allosteric Processes in a Two-domain Thermus thermophilus Hsp70 Molecular Chaperone

Objective To apply root cause analysis management in multidrug resistant Acinetobacter baumannii infection in ICU ward. Methods Six patients infected with multi-drug resistant Acinetobacter baumannii in ICU ward of our hospital were selected as the study object in February 2018. The instrument and equipment in ICU ward, the surface of bed unit, the diagnosis and treatment instrument, the sanitary ware, hands of medical staff and so on, were sampled. The root cause analysis method was used to find the source of infection and the route of transmission. The root causes of the outbreak of multi-drug resistant Acinetobacter baumannii were summarized and analyzed, and the intervention measures were taken. Results A total of 48 ICU environmental specimens were collected from 6 patients, of which 30 samples were positive showed by etiological examination, and the isolated strains were basically consistent with their drug resistance results (resistance to more than three types of antibiotics). It was inferred that the nosocomial infection of Acinetobacter baumannii in this outbreak was caused by the same pathogen contamination. At the same time, the detection results of Acinetobacter baumannii in ICU environment showed that the contamination of bed units and most of the surface of objects in the ward (the detection rate was 66%-75%), the disinfection and isolation measures not in place, and the non-standard hand hygiene of the staff were the main causes of the outbreak of nosocomial infection. Conclusions The main causes of the spread of multi-drug resistant Acinetobacter baumannii infection of ICU were found by root cause analysis, and the standard manual hygiene and contact isolation standards should be formulated and strictly implemented. It is an effective way to reduce the incidence of nosocomial infection of MDRAB by disinfection and sterilization measures on the surface of objects and the environment in the ward. There were no cases of multidrug resistant Acinetobacter baumannii infection in April 2018. Key words: Root cause analysis; ICU; Multidrug resistance; Acinetobacter baumannii; Nosocomial infection

Background: Bacteria causing respiratory infections tend to rapidly increase antibiotic resistance, prolong treatment time, increase treatment costs and increase mortality. Objectives: 1). To determine the proportion of bacterial strains isolated from sputum specimens; 2). To describe the antibiotic resistance of bacterial strains isolated from sputum specimens. Materials and methods: A cross-sectional descriptive study was carried out on 96 patients with positive sputum cultures using convenient sampling method. Results: Streptococcus pneumoniae (44.8%) was found to be the predominant pathogen isolated followed by Klebsiella pneumoniae (20.8%), Acinetobacter baumannii (13.5%) and Staphylococcus aureus (8.3%). The highest resistance was observed with piperacillin, ampicillin, erythromycin, cefaclor, azithromycin. Streptococcus pneumonia isolated were mostly resistant to azithromycin, cefaclor, and erythromycin (85.7%), while 0% resistance was observed for vancomycin, ampicillin and gentamycin. Klebsiella pneumoniae were highly resistant to ampicillin (95%), trimeth/sulfa (85%), and piperacillin (85%). Acinetobacter baumannii had a resistant rate of over 50% to most antibiotics, especially gentamycin and meropenem (84.6%). Staphylococcus aureus were completely resistant to ampicillin, clindamycin, penicillin, while vancomycin resistance was observed among 12.5% of the isolated bacteria. Conclusions: The most common pathogen was Streptococcus pneumoniae, Klebsiella pneumoniae, Acinetobacter baumannii and Staphylococcus aureus. The highest resistance was observed with piperacillin, ampicillin, erythromycin, cefaclor, and azithromycin. Streptococcus pneumoniae was highly resistant to macrolides. Klebsiella pneumoniae was highly resistant to most antibiotics of the 2nd, 3rd generation cephalosporins and beta lactams (penicillin and monobactam). Acinetobacter baumannii showed a noticeable resistance to fluoroquinolones, aminoglycosides, and 4th generation cephalosporins. Staphylococcus aureus was highly resistant to penicillin, lincosamides, fluoroquinolone, while 12.5% vancomycin resistance was observed.

Recently, to achieve cure, physicians have been resorting to overuse or misuse of antimicrobials to treat resistant infections, leading to the emergence of further resistant organisms. To overcome this issue, antimicrobial guidelines have been developed. Nevertheless, recently, controversy regarding the effect of adherence to antimicrobial guidelines on patient outcomes has been raised. Additionally, in multidrug-resistant (MDR) infections, rates of susceptibility to guideline-recommended agents have been reported to be low. Hence, herein, we aim to assess the impact of guideline-concordant, appropriate, and effective antimicrobial regimens on patient outcomes in MDR infections at the Ministry of National Guard Health Affairs (MNGHA), Jeddah, Saudi Arabia. This retrospective cross-sectional study was conducted at MNGHA, a 500-bed tertiary care hospital in Jeddah, Saudi Arabia. Saved microbiology lab samples that grew ESKAPE pathogens (Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) between October 2020 to September 2022 were collected and evaluated consecutively for MDR. Charts of all identified MDR isolates who had received empiric therapy were evaluated for concordance with hospital antimicrobial guidelines. Any deviation was evaluated for appropriateness by two independent researchers and a third expert. Patients under the age of 18 years were excluded, as the MNGHA hospital antimicrobial guidelines only included adults. Empiric treatment was deemed appropriate if (i) it was guideline-concordant or (ii) the deviation was approved by a third expert. The expert relied on the patient's clinical status by examining their disease severity, lab values, and physician's notes to adjudicate the appropriateness of the empiric treatment. If the administered antibiotic showed in vitro susceptibility, therapy was considered effective. The assessed outcomes included infection-associated death and clinical or microbiological cure. Over 2 years, a convenient sampling technique was applied to collect 569 samples. Out of these samples, a total of 405 samples with ESKAPE organisms were identified and evaluated, 121 of which were MDR. Four samples did not receive empirical treatment and so were excluded. A total of 117 samples were included in the analysis. The mean age in this study was 62.39 ± 18.17 years. Around three-fourths (77.8%, 91/117) of patients suffered from bacteremia, with the most common source of infection being complicated urinary tract infection. Guideline-concordant (68/117), appropriate (80/117), and effective (47/116) treatment demonstrated no statistically significant association with patient outcomes (P = 0.240, P = 0.526, and P = 0.747, respectively). Patients who required dose adjustment for initial empiric therapy received guideline-discordant empiric treatment more often (P = 0.003). Dose adjustments were judged based on hospital renal dosing guidelines and based on the patients' creatinine clearance. Basing the empirical treatment on previous susceptibility results elevates the odds of administering effective empirical treatment (OR: 2.44, CI: 1.06-5.60, P = 0.033). Interestingly, guideline-concordant treatment was associated with receiving ineffective empiric treatment (OR: 0.40, CI: 0.19-0.87, P = 0.019). Guideline-concordant, appropriate, or effective empiric antimicrobial treatment was not associated with better outcomes for patients with MDR ESKAPE organisms. Moreover, the administration of guideline-concordant treatment showed increased odds of giving ineffective treatment. On the other hand, considering previous susceptibility results in the decision of empiric regimens was associated with a higher chance of effective antibiotic administration. This study emphasizes the importance of identifying local MDR risk factors, utilizing previous culture reports, risk stratification, and continuous evaluation of outcomes to develop hospital-specific antimicrobial guidelines to manage the challenges of providing optimal empiric antimicrobials for patients with MDR infections.IMPORTANCEThis study evaluates the impact of guideline-concordant, appropriate, and effective antimicrobial treatment on patient outcome in MDR ESKAPE infections. Our study introduces a classification differentiating between guideline-concordant and clinically appropriate treatment to provide practical insight into the complexity of decision-making in MDR infections. Additionally, this study emphasizes the importance of identifying MDR risk factors, utilizing previous culture reports, risk stratification, and continuous evaluation of outcomes to develop hospital-specific guidelines to optimize empiric antimicrobials for MDR infections.

A new direction of research was established due to biofilms' infections caused by a mixture of fungal and bacterial species. Diagnosis of these infections becomes more difficult and high doses of drugs are used in treatment, especially in critically ill patients. The aim of the current study was to examine the effects of amphotericin B, in combination with imipenem or colistin against Candida albicans - Acinetobacter baumannii- Proteus mirabilis and Candida tropicalis - Acinetobacter baumannii -Proteus mirabilis polymicrobial biofilms. According to the microdilution method of the Clinical Laboratory Standards Institute (CLSI) published in documents M27-A3 (2008) and M07-A10 (2015) respectively, the susceptibility of the clinical isolates Candida yeasts to amphotericin B and Gram-negative bacteria to imipenem and colistin was determined. A Checkerboard assay was employed to evaluate the efficacy of drugs combinations. The 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyl tetrazolium bromide (MTT) reduction assay was used to quantify the biofilms. The combination amphotericin B/colistin and amphotericin B/imipenem did not produce obvious effects against the polymicrobial biofilms formed for 48 hours. Whereas colistin alone produced strong effects against Candida albicans-Acinetobacter baumannii and Candida albicans - Acinetobacter baumannii -Proteus mirabilis compared to Candida tropicalis - Acinetobacter baumannii and Candida tropicalis - Acinetobacter baumannii - Proteus mirabilis polymicrobial biofilms. For mixed Candida spp. bacterial biofilms, these results point to the difficulties in eradicating these biofilms, as well as in preventing their development.