Multidrug-resistant Gram-negative Bacilli Research Articles

A study on clinico-demographic and microbiological profile of surgical site infection (SSI) in a tertiary care hospital, Kolkata: An alarming trend

The Centres for Disease Control and Prevention (CDC) estimates surgical site infections SSI is major contributor of healthcare associated infections (HAI). Multidrug resistant (MDR) Gram-negative bacilli are emerging pathogens. This study aimed to determine the magnitude of SSI and identify predominant pathogens with their antimicrobial susceptibility patterns. It is a hospital-based descriptive cross-sectional study including 2070 suspected SSI specimens from 25809 surgeries between 1July 2021 to 30 June 2023. Organisms’ identification and AST was done by both conventional and automated methods. Data was collected and analysed on MS-Excel sheet with various charts and tables. In our study SSI rate was 6.3%, much higher than previous study (2.83%) from this institution. SSI rate was highest in plastic surgery (8.2%). Major pathogens of SSI were Gram-negative bacilli e.g., (26.34%), (25.59%) and (74.69%) was predominant among Gram-positive cocci. Gram-negative bacilli including enterobacterales and non-fermenter and showed resistance to major classes of broad- spectrum antibiotics. Methicillin resistance (MRSA) was 43.9%, which indicates need to improve infection control practices. Our study showed significant higher proportion of SSI as compared to previous studies from the same institute with alarming number of isolated MDR Gram-negative bacilli. So, this study focusses the need of robust infection control practices and strict implementation of antimicrobial stewardship to overcome challenges of antimicrobial resistance.

Ventriculitis due to multidrug-resistant gram-negative bacilli associated with external ventricular drain: evolution, treatment, and outcomes.

Nosocomial infectious ventriculitis caused by multidrug-resistant (MDR) Gram-negative bacilli associated with external ventricular drainage (EVD) placement poses a significant mortality burden and hospital costs. This study aims to analyze the characteristics, ventriculitis evolution, treatment, and outcomes of patients with ventriculitis due to MDR Gram-negative bacilli associated with EVD placement. A retrospective cohort study focusing on patients with nosocomial infection caused by MDR Gram-negative bacilli while on EVD was conducted from 2019 to 2022. Medical, laboratory, and microbiological records were collected. The antibiotic resistance of the Gram-negative bacilli isolated in the cerebrospinal fluid (CSF) of patients was analyzed. The risk factors were identified using univariate risk models and were analyzed using survival curves (Cox regression). An adjusted Cox proportional hazards model was also constructed. Among 530 patients with suspected EVD-associated ventriculitis, 64 patients with isolation of Gram-negative bacilli in CSF were included. The estimated mortality was 78.12%. Hemorrhages (intracranial, subarachnoid, and intraventricular) were observed in 69.8% of patients. Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most frequently isolated bacilli. In the univariate analysis, significant risk factors for mortality included arterial hypertension, a Glasgow Coma Scale (GCS) score of ≤ 8, invasive mechanical ventilation (IMV) upon hospital admission and during hospitalization, septic shock, and ineffective treatment. The adjusted Cox proportional hazards model revealed that septic shock (HR = 3.3, 95% CI = 1.5-7.2; p = 0.003) and ineffective treatment (HR = 3.2, 1.6-6.5, 0.001) were significant predictors. A high resistance to carbapenems was found for A. baumannii (91.3%) and P. aeruginosa (80.0%). Low resistance to colistin was found for A. baumannii (4.8%) and P. aeruginosa (12.5%). Ineffective treatment was an independent hazard factor for death in patients with ventriculitis caused by MDR Gram-negative bacilli associated with EVD.

Efficacy of Tamoxifen Metabolites in Combination with Colistin and Tigecycline in Experimental Murine Models of Escherichia coli and Acinetobacter baumannii

This study aimed to evaluate the potential of tamoxifen and N-desmethyltamoxifen metabolites as therapeutic agents against multidrug-resistant Escherichia coli and Acinetobacter baumannii, using a repurposing approach to shorten the time required to obtain a new effective treatment against multidrug-resistant bacterial infections. Characterisation and virulence studies were conducted on E. coli (colistin-susceptible C1-7-LE and colistin-resistant MCR-1+) and A. baumannii (tigecycline-susceptible Ab#9 and tigecycline-resistant Ab#186) strains. The efficacy of the metabolite mix (33.3% each) and N-desmethyltamoxifen in combination with colistimethate sodium (CMS) or tigecycline was evaluated in experimental models in mice. In the pneumonia model, N-desmethyltamoxifen exhibited significant efficacy against Ab#9 and both E. coli strains, especially E. coli MCR-1+ (−2.86 log10 CFU/g lungs, −5.88 log10 CFU/mL blood, and −50% mortality), and against the Ab#186 strain when combined with CMS (−2.27 log10 CFU/g lungs, −2.73 log10 CFU/mL blood, and −40% mortality) or tigecycline (−3.27 log10 CFU/g lungs, −4.95 log10 CFU/mL blood, and −50% mortality). Moreover, the metabolite mix in combination with both antibiotics decreased the bacterial concentrations in the lungs and blood for both A. baumannii strains. In the sepsis model, the significant efficacy of the metabolite mix was restricted to the colistin-susceptible E. coli C1-7-LE strain (−3.32 log10 CFU/g lung, −6.06 log10 CFU/mL blood, and −79% mortality). N-desmethyltamoxifen could be a new therapeutic option in combination with CMS or tigecycline for combating multidrug-resistant GNB, specifically A. baumannii.

Treatment of infections caused by multidrug-resistant Gram-negative bacilli: a practical approach by the Italian (SIMIT) and French (SPILF) Societies of Infectious Diseases

The emergence of multidrug-resistant Gram-negative bacilli, and the development of new antibiotics have complexified selection of optimal regimens. International guidelines are valuable tools, though limited by scarcity of high-quality randomized trials in many situations. A panel of experts from the French and Italian Societies of Infectious Diseases aimed to address unresolved issues in clinical practice based on their experience, updated literature review, and open discussions. The panel reached a consensus for the following 'first-choices': i) cefepime for ventilator-acquired pneumonia due to AmpC β-lactamase-producing Enterobacterales; ii) The β-lactam/β-lactamase inhibitors combination most active in vitro, or cefiderocol combined with fosfomycin, and aerosolized colistin or aminoglycosides, for severe pneumonia due to Pseudomonas aeruginosa resistant to ceftolozane-tazobactam; iii) high-dose piperacillin-tazobactam (including loading dose and continuous infusion), for complicated urinary tract infections (cUTIs) caused by ESBL-producing Enterobacterales with piperacillin-tazobactam MIC ≤8 mg/L; iv) high-dose cefepime for cUTIs due to AmpC β-lactamase-producing Enterobacterales other than Enterobacter species if cefepime MIC ≤2 mg/L; v) ceftolozane-tazobactam or ceftazidime-avibactam plus metronidazole for intra-abdominal infections (IAIs) due to 3rd generation cephalosporin-resistant Enterobacterales; vi) ceftazidime-avibactam plus aztreonam plus metronidazole for IAIs due to metallo β-lactamase-producing Enterobacterales; vii) ampicillin-sulbactam plus colistin for bloodstream infections (BSIs) caused by carbapenem-resistant Acinetobacter baumannii (CRAB); viii) meropenem-vaborbactam for BSI caused by KPC-producing Enterobacterales; ix) ceftazidime-avibactam plus fosfomycin for neurological infections caused by carbapenem-resistant P. aeruginosa. These expert choices were based on the necessary balance between antimicrobial stewardship principles, and the need to provide optimal treatment for individual patients in each situation.

STUDY OF MULTIDRUG-RESISTANT GRAM-NEGATIVE BACILLI IN URINARY TRACT INFECTIONS AND THEIR ANTIBIOGRAM AT A TERTIARY CARE HOSPITAL

Objective: To study the frequency of multidrug-resistant Gram-negative bacilli in urinary tract infections and antibiotic susceptibility pattern of multidrug-resistant Gram-negative bacilli in urinary tract infections.
 Methods: This study was conducted on urine samples received at the Department of Microbiology, Andhra Medical College, for a period of six months from August 2022 to January 2023. During the study period, a total of 3361 urine samples were processed and conventional microbiological techniques were used to isolate uropathogens. Antibiotic susceptibility was tested by the Kirby-Bauer Disc diffusion method and interpreted according to Central Laboratory Standard Institute (CLSI) guidelines 2022. Multidrug-resistant bacilli in this study were defined as Gram-negative bacilli that were resistant to at least one agent in three or more antibiotic classes.
 Results: Out of 3361 urine samples received from outpatient and inpatient departments of our hospital, 858 samples were culture positive-839 were Gram-negative isolates and 19 were Gram-positive isolates. Mean age was 40-60 y. Urinary tract infections were more common in females than males. Among Gram-negative bacilli isolated, Escherichia coli was the most common organism isolated-435(50.69%), followed by Klebsiella species-232(27.03%), Acinetobacter species-105(12.25%), Pseudomonas species-55(6.41%), Proteus species-10(1.16%), Citrobacter species-2(0.23%). Among Gram-positive cocci, Staphylococci-17(1.98%) and Enterococci-2(0.23%) were isolated. Out of 858 isolates, 177 (20.62%) were identified as multidrug-resistant bacilli and all were resistant to the drug groups Cephalosporins, Carbapenems and Quinolones. Most of the Multidrug-resistant gram-negative bacilli were sensitive to Fosfomycin and Nitrofurantoin.
 Conclusion: Multidrug-resistant Gram-negative bacilli in urinary tract infections have become a major health problem. Assessment of Risk factors, Surveillance of Resistance patterns and policies for proper use of antibiotics are urgently needed. 

In vitro activity of ceftazidime-avibactam against gram-negative bacteria in patients with bacteremia and skin and soft-tissue infections in Colombia 2019–2021

ObjectivesCeftazidime-avibactam (CAZ-AVI) is an option for infections caused by MDR gram-negative bacilli. In this study, we aimed to analyze the in vitro antimicrobial activity of CAZ-AVI and other antimicrobial agents against gram-negative bacilli that were collected in Colombia between 2019 and 2021 from patients with bacteremia and skin and soft-tissue infections (SSTIs). MethodsA total of 600 Enterobacterales and 259 P. aeruginosa strains were analyzed. The phenotypic resistance of isolates, particularly non-susceptibility to meropenem, multidrug-resistant (MDR) isolates, and difficult-to-treat (DTR) P. aeruginosa, was evaluated according to CLSI breakpoints. ResultsEnterobacterales had the most susceptibility to CAZ-AVI (96.5 %) and tigecycline (95 %). Tigecycline and CAZ-AVI were the antimicrobial agents with the most in vitro activity against carbapenem-resistant Enterobacterales (CRE). CAZ-AVI was the antimicrobial treatment with the most activity against P. aeruginosa. ConclusionsTigecycline and CAZ-AVI were the antimicrobial agents with the most activity against CRE and MDR Enterobacterales. For P. aeruginosa, CAZ-AVI was the antimicrobial treatment with the most in vitro activity.

Retrospective Observational Study to Assess Safety and Tolerability of Nebulized Colistin for the Treatment of Patients With Pneumonia in Real-World Settings in Respiratory ICU.

Colistin is used to treat hospital-acquired pneumonia and ventilator-associated pneumonia. However, direct drug deposition at the site of infection may improve its efficacy and reduce systemic exposure. The aim of this study was to assess the safety and tolerability of nebulized colistin among Indian patients diagnosed with pneumonia caused by multidrug-resistant gram-negative bacilli in real-world settings. We retrospectively reviewed the medical records of patients treated with nebulized colistin for pneumonia. We assessed the adverse events and relevant abnormal laboratory findings of nebulized colistin therapy. All enrolled patients (N=30, males: 22, females: 8; average age: 71.06 years) were treated for 13.36 days. Almost 80% of patients had a history of shortness of breath, which was a major symptom when they were admitted to the hospital. The patients were administered nebulized colistin for an average of six days (8 hours per day). The most common dosing schedule was 1 million international units (MIU)/8 hours. No serious adverse event was observed, and only one patient died while on the treatment but the death was not related to colistin treatment. The average sequential organ failure assessment score for all patients was 6.5. Our study demonstrated the efficient clinical utility and well-tolerated safety profile of nebulized colistin in the treatment of patients with pneumonia. Neurotoxicity and nephrotoxicity were not reported. Since a significant percentage of patients were with chronic respiratory diseases, our study further indicates the safety and effectiveness of nebulized colistin in chronic obstructive pulmonary disease (COPD) patients too.

Epidemiology and clinical characteristics of patients with healthcare-acquired multidrug-resistant Gram-negative bacilli: a retrospective study from a tertiary care hospital

The numbers of infections caused by Gram-negative bacteria (GNB) that produce extended-spectrum beta-lactamases (ESBLs) and those that are carbapenem resistant, especially Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae), are increasing, and these infections are becoming a global public health problem. The aim of this study was to assess the prevalence of infections caused by ESBL-producing and carbapenem-resistant Gram-negative bacilli in patients hospitalized at An-Najah National University Hospital in Nablus, Palestine, and to provide healthcare workers with valuable information on the treatment of these infections. A retrospective cross-sectional investigation was conducted at a large tertiary care teaching hospital. The study included patients admitted to the hospital between January and December 2021, from whom ESBL-producing and carbapenem-resistant Gram-negative bacilli were isolated. The patients' clinical and demographic information was obtained from the hospital information system. In addition, information regarding the bacterial isolates and antibiotic resistance was obtained from the hospital's microbiology laboratory. This study included a total of 188 patients—91 males (48.4%) and 97 females (51.6%). The general surgical ward accounted for the highest proportion of infections (30.9%), followed by the surgical ICU (12.2%). The most common infections were caused by ESBL-producing E. coli, which accounted for 62.8% of the cases. Among them, urinary tract infections caused by this microorganism were the most prevalent (44.7% of patients). Over 50% of the patients (54.2%) had a history of antibiotic use, and 77.8% had been hospitalized within the past three months. ESBL-producing E. coli was significantly isolated from blood cultures (p-value = 0.000), and CR-K. pneumoniae was significantly isolated from endotracheal isolates (p-value = 0.001). This study emphasizes the concerning frequency of healthcare-acquired infections caused by ESBL-producing and carbapenem-resistant GNB in a tertiary care hospital. The substantial prevalence of antibiotic resistance presents considerable obstacles to the successful administration of routinely employed antibiotics. The results highlight the immediate need for improved antimicrobial stewardship and the implementation of infection control strategies to reduce the effects of multidrug-resistant GNB on patient well-being and public health.

Molecular Epidemiology of Escherichia coli Resistant to Carbapenems, Fluoroquinolones, and Aminoglycosides Isolated from One of the Largest Hospitals in Vietnam in 2014-2019.

Multidrug-resistant (MDR) Gram-negative bacilli including carbapenem-resistant Gram-negative Enterobacteriaceae (CRE) threaten global health. Little is known, however, about the distribution of antimicrobial resistance genes in MDR isolated from patients in Vietnamese hospitals. In this study, we collected MDR Escherichia coli, defined as E. coli resistance against all fluoroquinolones, aminoglycosides, and carbapenems. This study was designed to clarify the molecular epidemiology of Escherichia coli isolates resistant to carbapenems, fluoroquinolones, and aminoglycosides isolated from patients admitted to one of the largest hospitals in Vietnam in 2014-2019 based on both whole-genome sequencing (WGS) and phenotypic data. Methodology. Sixty-seven Vietnamese isolates screened by drug resistance by the disk test were subjected to WGS, and their sequences were analyzed to determine their multilocus sequence type (MLST), O-types, H-types, distribution of drug resistance genes, plasmid types, pathogenicity islands (PIs), virulence factor distribution, and phylogenetic evolution using the WGS data. Among the STs detected, ST410 was relatively dominant. Dominant O-types and H-types were O102 and H9 and showed some links, such as those between O102 and H8. The most dominant plasmid type and carbapenemase type were 4 and NDM-5, respectively. MLST, O-types, H-types, plasmid types, and types of carbapenemases were very heterogeneous among the isolates, with no clear correlation between them. Dominant plasmid type carrying drug resistance gene was IncQ1_1. The percentage of isolates positive for drug resistance genes, such as anti-beta-lactams and aminoglycosides, was relatively high because the isolates screened were resistant to carbapenems, fluoroquinolones, and aminoglycosides. MDR E. coli isolates isolated at a high-volume Vietnamese hospital were very heterogeneous, suggesting that they were acquired from different sources, including nosocomial infection, animals, and water. Eradication of MDR E. coli from hospitals and other clinical environments is very challenging because a single measure may be ineffective.

Incidence of catheter-associated urinary tract infections by Gram-negative bacilli and their ESBL and carbapenemase production in specialized hospitals of Bahir Dar, northwest Ethiopia

BackgroundCatheter-associated urinary tract infections (CAUTIs) due to multidrug-resistant Gram-negative bacilli (GNB) is a common concern globally. Investigating the incidence of CAUTI and associated antibiotic resistance has paramount importance from the health care associated infections perspective. This study therefore assessed the incidence of CAUTIs due to GNB and the production of extended-spectrum beta-lactamase (ESBL) and carbapenemase among inpatients in specialized hospitals of Northwest, Ethiopia.MethodsA total of 363 patients with indwelling urinary catheters who were admitted in the hospital for > 48 h were consecutively enrolled and followed from 3 to 18 days. Data were collected through interviewing and review of medical records. Patients who developed at least one of the following: fever (> 38 OC), suprapubic tenderness, or costovertebral angle pain, coupled with a GNB positive urine culture of ≥ 103 CFU/mL with no more than two bacterial species were defined as CAUTI. The ESBL and carbapenemase production were detected and identified by chromogenic medium. Logistic regression analysis was done to identify associated factors.ResultsFrom 363 patients followed, the incidence rate of CAUTI was 27.8 per 1000 catheter days. Catheterization for ≥ 8 days (AOR = 10.6, 95%CI:1.8–62.1) and hospitalization for > 10 days (AOR = 8.1, 95%CI: 2.4–27.2) were the factors significantly associated with CAUTIs. E. coli (n = 18, 34.6%), Proteus species (n = 7, 13.5%), and P. aeruginosa (n = 6, 11.5%) were the most frequent GNB. Isolates revealed high rates of resistance to amoxicillin-clavulanic acid (100%), cefazolin (n = 51, 98%), ceftazidime (n = 47, 90%) and cefotaxime (n = 46, 88%). Most of the GNB isolates (86.5%) were multidrug-resistant. Overall, 19.2% and 5.8% of GNB isolates were ESBL and carbapenemase producers, respectively.ConclusionsIncidence of CAUTI with Gram-negative bacilli is high. As most of the GNB isolates are MDR and showed a super high rate of resistance to amoxicillin-clavulanic and third-generation cephalosporins, empirical treatment with these substances is virtually ineffective in patients with suspected GNB infection in Ethiopia. The expression of ESBL and carbapenemase among GNB isolates is also a concern. Therefore, improved infection prevention and control measures, careful use of catheters and third generation of cephalosporins are needed to improve patient outcomes and reduce the burden of CAUTIs and the spreading of antimicrobial resistance.

Colistin and Polymyxin B sensitivity by broth microdilution among carbapenem-resistant clinical isolates of Gram-negative bacilli

Introduction and Aim: The increasing incidence of multidrug-resistant gram-negative bacilli (MDR-GNB) in recent times has led to the revival of older neglected antibiotics such as Polymyxins. Hence, there is a need to determine the minimum inhibitory concentration (MIC) of these antibiotics by conventional and automated antibiotic sensitivity testing methods to assess their clinical utility. This study aimed to assess the in vitro sensitivity of clinical isolates grown with carbapenem-resistant GNB (CR-GNB) to Colistin and Polymyxin B by broth micro-dilution method (BMD).   Materials and Methods: Thirty isolates of CR-GNB obtained from various clinical samples received in the microbiology laboratory of Yenepoya Medical College Hospital between August 2018 to November 2019 were included in the study. In vitro assessment of Colistin and Polymyxin B sensitivity among CR-GNB was performed by BMD as per CLSI guidelines.   Results: Twelve isolates (40%) were carbapenemase producers. Among the 30 isolates of CR-GNB, 56.6% and 63.3 % of them were sensitive to Colistin and Polymyxin, respectively. Colistin MICs of 12 isolates obtained by BMD assay were concordant with the MICs obtained by BD Phoenix.   Conclusion: The results of this study indicate that Colistin and Polymyxin B can be considered as reserve therapeutic agents for treating infections caused by CR-GNB after obtaining the in vitro sensitivity results.

In vitro activity of cefiderocol and comparator antibiotics against multidrug-resistant non-fermenting Gram-negative bacilli.

This study evaluated the in vitro activity of cefiderocol, ceftazidime/avibactam, and aztreonam/avibactam against clinically important multidrug-resistant non-fermenting Gram-negative bacilli. Bacteraemic isolates of 126 multidrug-resistant Acinetobacter baumannii (MDRAB), 110 imipenem-resistant Pseudamoas aeruginosa [including 14 difficult-to-treat resistant P. aeruginosa (DTRPA)], 45 beta-lactam-non-susceptible Burkholderia cepacia complex (BCC), 47 levofloxacin or trimethoprim/sulfamethoxazole-non-susceptible Stenotrophomonas maltophilia and 22 ciprofloxacin-non-susceptible Elizabethkingia spp. collected between 2019 and 2021 were subjected to MIC determination for cefiderocol, ceftazidime/avibactam and aztreonam/avibactam. The MIC50/90s of cefiderocol for drug-resistant A. baumannii, P. aeruginosa, BCC, S. maltophilia and Elizabethkingia spp. were 0.25/2, 0.25/1, ≤0.06/≤0.06, ≤0.06/0.25 and >32/>32 mg/L, respectively. Cefiderocol inhibited 94.4% (119/126) of MDRAB, 100% of imipenem-resistant P. aeruginosa, 100% of DTRPA and 100% of BCC at an MIC ≤4 mg/L, and 97.9% (46/47) of S. maltophilia at ≤1 mg/L. Ceftazidime/avibactam inhibited 76.4% (84/110) of imipenem-resistant P. aeruginosa, 21.4% (3/14) of DTRPA and 68.9% (31/45) of BCC at an MIC ≤8 mg/L. Aztreonam/avibactam had MIC50/90s of 16/>32, 8/16 and 4/8 mg/L for imipenem-resistant P. aeruginosa, BCC and S. maltophilia, respectively. At ≤8 mg/L, aztreonam/avibactam inhibited 7.1% (1/14) of DTRPA and 93.6% (44/47) of S. maltophilia isolates. Elizabethkingia spp. demonstrated high MICs for cefiderocol, ceftazidime/avibactam and aztreonam/avibactam, with all MIC50s and MIC90s > 32 mg/L. Cefiderocol may serve as an alternative treatment for multidrug-resistant A. baumannii, P. aeruginosa, BCC and S. maltophilia when other antibiotics have been ineffective or intolerable. The role of ceftazidime/avibactam and aztreonam/avibactam in the management of BCC or S. maltophilia infections warrants further investigation.

A comparative evaluation of colistin Minimum Inhibitory Concentration determination by reference broth microdilution with other commonly used phenotypic methods in Multidrug-Resistant Gram-negative bacilli

Background: over the past decade, the dependency on colistin as a last resort antibiotic has driven the global emergence of colistin resistance among many bacterial species. This study comparatively evaluated the colistin Minimum Inhibitory Concentration (MIC) by various phenotypic methods, including the reference method of Broth Microdilution (BMD), other approved methods of Colistin Broth Disk Elution (CBDE), and Colistin Agar Test (CAT) and widely available method of Epsilometer Test (E-test) among Multidrug Resistant (MDR) Gram-negative bacteria. Methods: ninety Gram-negative bacterial isolates that were resistant to three or more classes of drugs (MDR) were included in the study. All the MDR isolates were subjected to colistin susceptibility determination by BMD, CBDE, CAT, and E-test. Results: amongst 1118 samples, 90 (8.05%) samples yielded MDR Gram-negative bacilli. All the MDR Gram-negative isolates were colistin intermediate by all four methods of phenotypic colistin susceptibility. Three Acinetobacter baumannii and two Klebsiella pneumoniae isolates that had MIC of 2 μg/mL by BMD, displayed MIC of <1 μg/mL by CBDE and CAT. Three isolates (2 Citrobacter koseri and 1 Enterobacter spp.) showed higher MIC by the E-strip method in comparison to BMD. Conclusions: our study holds significance, as there is a paucity of data comparing the four phenotypic methods for colistin MIC determination; BMD is the most reliable, gold standard method, but it is labor-intensive and requires technical expertise. In the present study, CBDE and CAT methods showed good concordance with BMD, and are easy to perform with limited logistics. Thus, they can be used as an alternative to BMD. We found that even though the Etest method was less accurate, it can still be used with caution to exclude the possibility of colistin resistance.

Aerobic Bacterial Profile of Sepsis and Its Antibiotic Susceptibility Pattern Among Patients in a Rural Tertiary Care Center.

Background Bloodstream infections (BSI) are one of the most life-threatening infections associated with high morbidity and mortality. Early diagnosis with appropriate and timely treatment improves the patient outcome. The recent surge in multidrug-resistant (MDR) strains is a matter of concern. This study aims to determine the bacterial etiology and antibiotic sensitivity pattern in BSI among different age groups. Materials and methods The microbiological data of blood culture and sensitivity between April 2019 and April 2021 were extracted from the laboratory recordsand analyzed for the bacterial profile and antibiotic sensitivity pattern. Results Out of the total 3893 blood cultures received during the study period from April 2019 to April 2021, 194 pathogens were isolated, accounting for a prevalence of 4.98%. Among 194 patients with culture-proven BSI, 54.12% (105/194) were adults, and 45.87% (89/194) were children. Of these 194 bacterial isolates, 58.76% (114/194) were gram-negative bacteria, and 41.24% (80/194) were gram-positive bacteria. With regard to the bacteria isolated,Enterococcusspecies with 23.71% (46/194) andAcinetobacterspecies with 22.16% (43/194) were the most common bacteria. The prevalence of MDR was 59.27% (115/194). Notable MDR types were methicillin-resistantStaphylococcus aureus(MRSA) in 15/22 (68.2%) and extended-spectrum beta-lactamase (ESBL) producers in 15/48 (31.25%) cases. Conclusion There is a significant geographical diversity of bacteria causing sepsis and their antibiotic susceptibility pattern. Recent trends showthat multidrug-resistant gram-negative bacilli are the predominant isolates causing BSI. Increased antibiotic resistance is leading to treatment failure and poor clinical outcomes. Hence, there is a need to monitor antibiotic resistance among patients with BSI.

Distribution and antimicrobial resistance analysis of gram-negative bacilli isolated from a tertiary hospital in Central China: a 10-year retrospective study from 2012 to 2021.

Gram-negative bacilli are one of the most common causes of various infections in clinical. The emergence and global spread of multi-drug resistant gram-negative bacilli has become a major challenge in the global public health field. A total of 51,189 non-repetitive strains of gram-negative bacilli were isolated in clinical settings. The antimicrobial susceptibility testing was conducted by using the automated VITEK 2 compact system and the matched AST susceptibility test card, complemented by the disk diffusion method. The antimicrobial susceptibility results were interpreted by CLSI. Rates of MDR and XDR in Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa were investigated. Used the chi-square test to determine whether the antimicrobial resistance rates of four major gram-negative bacilli isolated from ICU and non-ICU department have statistical differences. Escherichia coli (31.4%), Klebsiella spp. (21.2%), Acinetobacter spp. (13.8%), and P. aeruginosa (11.0%) were the most frequently isolated gram-negative bacilli. Escherichia coli was the top one organism isolated from urinary tract (68.4%), bloodstream (39.9%), body fluid (33.2%), wound and pus (37%), except for respiratory tract (8.8%). Whereas Acinetobacter baumannii and K. pneumoniae were the major isolated organisms from respiratory tract. Acinetobacter baumannii showed high resistance to fluoroquinolones, β-lactam/β-lactamase inhibitor combinations class, ceftazidime, cefepime, imipenem, and meropenem, the resistance rates reached more than 70%. Ceftazidime showed a lower resistance rate to E. coli than ceftriaxone. For E. coli, fluoroquinolones showed a high resistance rate (ciprofloxacin 61.36% and levofloxacin 53.97%), whereas amikacin, carbapenems exhibited a lower resistance rate fluctuating at 2%. Acinetobacter baumannii and K. pneumoniae showed rapid increases in carbapenem resistance whereas E. coli had the lowest resistance rate and remain stable at 2%. Acinetobacter baumannii exhibited the highest rate of MDR and XDR, reaching 60-80 and 45-55%, respectively. Compared to non-ICU departments, the resistance rates of four major gram-negative bacilli in the ICU department were much higher and the differences were statistically significant (p < 0.05). Amikacin, carbapenems, and piperacillin/tazobactam exhibited relatively high sensitivity, whereas fluoroquinolones showed high resistance rate whether they can be the first-line antimicrobials for empirical treatment of UTI should take more consideration. The gram-negative bacilli in ICU were more resistance than that in non-ICU. These findings are helpful for clinicians using antimicrobials reasonably.

Superbugs: An invicible threat in post antibiotic era

BackgroundSuperbug resistance is a very rare, invincible global problem arising as a threat in hospitals as well as in the community. Methicillin-Resistant Staphylococcus aureus(MRSA), Vancomycin-Resistant Enterococci (VRE) and Multidrug-resistant Gram-negative bacilli (MDR-GNB) etc are the most deadly contagious strains. This study discloses the prevalence and risk factors associated with superbugs there by aiding the adoption of preventive measures to reduce resistance patterns in hospital settings. AimIdentification of the superbug that predominantly shows antibiotic resistance in hospitals and analyzing the risk factors for the occurrence of antibiotic resistance. Materials and methodsA prospective observational study was conducted for one year, from 1st September 2019 to 31st July 2020 to evaluate the prevalence and risk factors of antibiotic-resistant superbugs among the 80 patients selected from the various departments (General Medicine, General Surgery, Nephrology, Pulmonology,Orthopedics, orthopaedicsurgery,Neurology, Urology,and Neurosurgery) of a tertiary care referral hospital. ResultsMethicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa were antibiotic-resistant superbugs that predominantly showed resistance in hospital settings. ConclusionPseudomonas aeruginosa and Methicillin-resistant superbugs were the predominantly found superbugs in hospital settings. Major risk factors for antibiotic-resistant superbugs were found to be Prolonged hospitalization, previous antibiotic therapy, failure to take the antibiotic as prescribed by physicians, patient co-morbid conditions, prophylactic use of antibiotics, patient diet etc.

Effectiveness of tailored screening for multidrug-resistant organisms upon admission to an intensive care unit in the United Arab Emirates.

Multidrug-resistant organism (MDRO) screening may identify high-risk patients for MDRO infection and curb the spread of these resistant pathogens. However, the heterogeneous practices in MDRO screening and the diversity of MDRO risk factors necessitate a tailored approach for successful implementation. This study aimed to evaluate the performance of tailored MDRO screening in predicting MDRO carriage compared to universal screening. Critically ill patients who underwent MDRO screening tests upon intensive care unit admission between September 2015 and December 2019 were included in the study. A risk-predicting model was developed using risk factors identified through multivariable logistic regression analysis. If an individual had one or more identified risk factors, the individual was deemed to be at risk of MDRO carriage and undergo tailored screening. The sensitivity of tailored screening was compared with universal screening for methicillin-resistant Staphylococcus aureus (MRSA)and multidrug-resistant Gram-negative bacilli (carbapenem-resistant Acinetobacter baumannii and carbapenem-resistant Enterobacterales). The use of tracheostomy or endotracheal tubes, previous antibiotic exposure, previous multidrug-resistant Gram-negative bacilli carriage history, admission to the medical department, peripheral vascular disease, and liver disease were associated with positive screening for multidrug-resistant Gram-negative bacilli. These six risk factors accounted for all positive screening for multidrug-resistant Gram-negative bacilli, requiring 38.6% of all tests. Notably, MRSA had different risk factor profiles, and the risk factor-based screening approach detected only 43.1% (31 out of 72) of MRSA-positive cases. Tailored screening based on identified risk factors showed variable sensitivities to individual MDROs compared to universal screening. A tailored screening approach for individual MDROs may enhance the overall effectiveness of MDRO screening programs.

Investigation of Nosocomial Urinary Tract Infections Post Transplantation, Main Pathogens, and Sensitivity Tests

Background: Regarding end-stage organ disease, transplantation is recommended as the best therapeutic management. After organ transplantation, the incidence of nosocomial urinary tract infections (NUTIs) due to multidrug-resistant Gram-negative bacilli increases. background: Regarding end-stage organ disease organ transplantation recommended as the best therapeutic management. After organ transplantation the incidence of urinary tract infections (UTIs) due to multidrug-resistant Gram-negative bacilli is increasing Aim: The study aimed to investigate NUTIs post-transplantation, the main pathogens involved, and sensitivity tests conducted in a tertiary hospital in Isfahan, Iran. Methods: A retrospective survey on patients admitted to a tertiary hospital in Isfahan (Alzahra), Iran, was performed between 27 March, 2017, and 9 February, 2022. The information recorded included the date of infection, date of hospitalization, gender, age, type of pathogens, and resistance or sensitivity to antibiotics. Results: 73 kidney transplant recipients (61% females) with a mean age of 43. 2 ± 15.1 years were included. Within this population involving both genders, the main pathogens involved in NUTIs were as follows: Escherichia coli (30%), Klebsiella pneumonia (19%), Candida albicans and non-albicans (14%), Enterococcus faecalis (12%), Enterobacteriaceae (8%), Pseudomonas aeruginosa (6%), Staphylococcus spp. (6%), Acinetobacter baumannii (4%), and Streptococcus spp. (4%). Antibiotic susceptibility testing showed the most sensitivity of isolates against amikacin (n=29; 66%), meropenem (n= 28; 64%), piperacillin/tazobactam (n=26; 54%), cefepime (n= 25; 40%), ceftazidime (n= 27; 30%), ciprofloxacin (n= 40; 18%), and co-trimoxazole (n= 29; 10%). result: 72 kidney transplant recipients (61 Conclusion: Escherichia coli, Klebsiella pneumonia, and Candida spp. are the major causes of NUTIs within organ-transplanted recipients. Amikacin, meropenem, and piperacillin/tazobactam have shown more than 50% sensitivity against isolates. Further evidence-based management associated with the different spectrum antibiotics and overall antimicrobial success rate is recommended to be advantageous.

High oral carriage of multidrug resistant Gram-negative bacilli in adolescents: the SOPKARD-Junior study.

The colonization of the oral cavity by potentially pathogenic antimicrobial-resistant bacteria in adolescents and its consequences is very poorly understood. The present study focused on the occurrence of oral colonization by Gram-negative bacilli (GNB) and their multidrug resistance, including the production of extended-spectrum β-lactamases (ESBLs) and carbapenemases, among healthy adolescents and risk factors associated with GNB colonization. This study was conducted as part of "A program for the early detection of risk factors for lifestyle diseases SOPKARD-Junior" (SOPKARD-Junior). Oral samples were collected from 182 adolescents from four public elementary schools in Sopot, Poland, aged 13-14 years. Bacterial strains were identified by the MALDI-TOF MS method. Screening of antimicrobial resistance was performed using a disk diffusion method. The NG-Test® CARBA-5 was used to detect and differentiate the five most widely distributed carbapenemases. Demographic and clinical data were collected and statistical analysis of risk factors was performed. A total of 68 out of 182 (37.4%) healthy adolescents was documented oral colonization with Gram-negative bacilli, including 50/182 (27.5%) multidrug resistant (MDR-GNB) strains. Over 60% of oral carriage concerned three main genera Enterobacter spp., Pseudomonas spp., and Serratia spp., which were detected in 22.1%, 19.1%, and 19.1% of participants, respectively. Citrobacter spp., Escherichia coli, Klebsiella spp., Hafnia spp., Aeromonas spp., Acinetobacter spp., and Stenotrophomonas spp. were also isolated. The antimicrobial resistance to ampicillin (100%), ceftazidime (69.1%), meropenem (60.3%), gentamycin (60.3%), piperacillin/tazobactam (52.9%), and piperacillin (45.6%) were the most common. Among 73.5% GNB strains multidrug resistance was observed, including all Pseudomonas spp. strains. Among MDR-GNB, 30.4% were resistant to four groups of antibiotics, half of the MDR Pseudomonas spp. strains were resistant to 10 groups of antibiotics. Extended-spectrum β-lactamases were produced by Enterobacter cloacae, Klebsiella spp., and Serratia spp. (7.4%). Colonization by ESBLs-positive GNB strains was significantly associated with recurrent respiratory infections, nasal congestion, and bronchitis (p<0.05). Our study revealed high oral carriage of multi-drug resistant Gram-negative bacilli in healthy adolescents and the association of ESBL-producing strains with respiratory infections. Further studies on oral colonization with GNB are necessary due to the possibility of distinct infections and the acquisition of antibiotic resistance by resident microbiota.

Optimization of oil yield of Pelargonium graveolens L'Hér using Box-Behnken design in relation to its antimicrobial activity and in silico study

Pelargonium graveolens L'Hér is an important species of genus Pelargonium with an economic value. The unique rose scent of its oil is used in perfume and cosmetic industry. The oil is characterized by the presence of citronellol, geraniol and rose oxide. Fresh aerial parts of P. graveolens at GC–MS analysis of four seasons revealed that autumn constituted the highest yield of the oil. For the first time, optimization of the yield of extracted oil of P. graveolens was performed employing 3-level Box-Behnken design using 3-factors. The GC–MS analysis of the essential oil was performed for the 17-runs. The optimized extraction of the oil was performed employing numerical optimization and studied for antimicrobial, Minimum Inhibitory Concentration (MIC) and biofilm inhibitory activities. The 3 factors followed rank (plant material amount > water volume > NaCl percent in water), in their magnitude of effect on increasing yield of the oil. Increasing the plant material amount increased the yield of the oil by 6-folds compared to NaCl percent in water. The optimized yield of oil (4 ml) was obtained from extraction criteria (150 g of plant, 750 ml of water and 3.585% (26.85 g) of NaCl). Computational docking was performed to overcome the multi-drug resistant Gram-negative bacilli targeting undecaprenyl pyrophosphate synthase (UPPS). The optimized oil exhibited a promising inhibitory activity against Gram-negative bacteria (K. pneumonia and P. aeruginosa) with significant antibiofilm action (P < 0.05). Moreover, it exerted a synergistic effect when combined with various antibiotics (Cefoxitin, Cloxacillin, Oxacillin and Vancomycin) against MRSA clinical strains.