Prevalence Of Multidrug-resistant Acinetobacter Baumannii Research Articles

Characterization of Aminoglycoside-Resistant Acinetobacter baumannii in Respiratory Specimens: Phenotypic and Molecular Insights

Background: The global rise of antibiotic-resistant bacteria presents a formidable challenge to healthcare systems, with Acinetobacter baumannii standing out as a particularly resilient pathogen in hospital settings. The propensity of this organism to exhibit multidrug resistance complicates treatment protocols and underscores the need for in-depth research into its resistance mechanisms. Objective: The objective of this study was to characterize the allelotypic and molecular features of aminoglycoside-resistant Acinetobacter baumannii isolates from respiratory specimens and to determine their antibiotic susceptibility profiles to inform better clinical decision-making and treatment approaches. Methods: This cross-sectional study was conducted at the different labs of various institute of Lahore. A total of 50 respiratory specimens were cultured on selective media. The isolates underwent phenotypic characterization through colony morphology and biochemical tests. Antimicrobial susceptibility was assessed using the disc diffusion method, and molecular analysis was performed using polymerase chain reaction (PCR) to identify the armA gene associated with aminoglycoside resistance. Statistical analysis was executed using SPSS Version 25. Results: Of the 50 isolates, 54% were from male patients and 46% from female patients. Antibiotic resistance was alarmingly high, with resistance rates of 92% for TZP, 90% for FEP, CAZ, IPM, MEM, 86% for AK, 74% for CN, 54% for TOB, and 48% for DO. The presence of the armA gene was detected in 86% of the isolates, suggesting a link to the high levels of aminoglycoside resistance observed. Conclusion: The study revealed a high prevalence of multidrug-resistant Acinetobacter baumannii in respiratory specimens, with significant resistance to commonly used antibiotics. These findings highlight the necessity for continuous surveillance of antibiotic resistance patterns and call for innovative approaches to antimicrobial therapy.

The Prevalence of Multidrug-Resistant Acinetobacter baumannii and Its Vaccination Status among Healthcare Providers.

There is growing concern among healthcare providers worldwide regarding the prevalence of multidrug-resistant Acinetobacter baumannii (A. baumannii). Some of the worst hospital-acquired infections, often in intensive care units (ICUs), are caused by this bacterial pathogen. In recent years, the rise in multidrug-resistant A. baumannii has been linked to the overuse of antimicrobial drugs and the lack of adequate infection control measures. Infections caused by this bacterial pathogen are the result of prolonged hospitalization and ICU stays, and they are associated with increased morbidity and mortality. This review outlines the epidemiology, risk factors, and antimicrobial resistance associated with A. baumannii in various countries, with a special focus on the Kingdom of Saudi Arabia. In response to the growing concern regarding this drug-resistant bacteria, fundamental information about its pathology has been incorporated into the development of vaccines. Although these vaccines have been successful in animal models, their effectiveness in humans remains unproven. The review will discuss the development of A. baumannii vaccines, potential related obstacles, and efforts to find an effective strategy against this pathogen.

Analysis of Healthcare-Associated Infections in COVID-19 patients admitted to an Intensive Care Unit

Introduction: Healthcare-associated infections (HAIs) are a major public health problem. Objective: To evaluate the profile of SAIs in patients with COVID-19 admitted to the intensive care unit (ICU) in a public hospital in southern Brazil. Method: Cross-sectional, retrospective study, conducted between March 2020 to October 2021, of patients with COVID-19 hospitalized in ICU with IRAS. Results: The main infection was ventilator-associated pneumonia (230 cases), followed by urinary tract infections (160 cases) and bloodstream infections (103 cases), associated with the presence of catheter. Regarding the main microorganisms, the high prevalence of multidrug-resistant Acinetobacter baumannii (112 cases) was noteworthy in ventilator-associated pneumonia, with an increasing increase in the analyzed period. The expressiveness of fungal infections, especially Candida albicans, was evidenced. Patients with ventilator-associated pneumonia had lower mortality rates (OR= 0.31; p= 0.034), which increased significantly with increasing days of ICU stay (OR= 3.02; p= 0.0000007). The profile of the patients was mainly male, with significant use of antimicrobials and antifungals, high degree of pulmonary impairment, with evolution to death. Among the predictors of mortality, the most impacting was acute renal failure (OR= 4.45; p=0.0002) and the least related was pulmonary thromboembolism (OR=0.47; p= 0.0167). Conclusion: The high percentage of bacterial and fungal IRAS was evidenced. The highest mortality predictor was acute renal failure, while the lowest mortality was pulmonary thromboembolism.

Epidemiological and comparative genomic analyses of Multidrug-Resistant Acinetobacter baumannii collected between 2020 and 2022 in Liaocheng City, Shandong Province, China

The emergence and prevalence of multidrug-resistant Acinetobacter baumannii (MRAB) poses a huge challenge to clinical treatment. To investigate the genetic and epidemiologic characteristics of MRAB in Liaocheng, China, and to explore potential resistance mechanisms, 56 MRAB strains were collected from the clinical departments of seven hospitals in Liaocheng between 2020 and 2022. Molecular typing, antimicrobial resistance patterns, and epidemiological characteristics were determined by genome sequencing and comparative genome analysis. Sequence type (ST) 540 was the most prevalent ST of the 56 MRAB in Liaocheng, and most strains (92.86%) were grouped into CC92. Core genome multilocus sequence typing subdivided the strains according to the number of allelic differences and could distinguish different outbreaks caused by ST540 isolates in the hospitals. All the isolates harbored blaOXA-23 and blaADC-25, and at least 92.86% of the isolates were resistant to 10 antibiotics. The major MRAB epidemic clone detected in Liaocheng was ST540, which was different from the results reported in other regions in China. Furthermore, several inter-hospital transmissions of ST540 isolates were observed. The findings highlight the urgent need for effective nosocomial infection control measures and the continuous surveillance of ST540 MRAB in Liaocheng.

Preventative treatment with Fluorothiazinon suppressed Acinetobacter baumannii-associated septicemia in mice.

The high prevalence of multidrug-resistant Acinetobacter baumannii has emerged as a serious problem in the treatment of nosocomial infections in the past three decades. Recently, we developed a new small-molecule inhibitor belonging to a class of 2,4-disubstituted-4H-[1,3,4]-thiadiazine-5-ones, Fluorothiazinon (FT, previously called CL-55). FT effectively suppressed the T3SS of Chlamydia spp., Pseudomonas aeruginosa, and Salmonella sp. without affecting bacterial growth in vitro. In this study, we describe that prophylactic use of FT for 4 days prior to challenge with resistant clinical isolates of A. baumannii (ABT-897-17 and 52TS19) suppressed septic infection in mice, resulting in improved survival, limited bacteraemia and decreased bacterial load in the organs of the mice. We show that FT had an inhibitory effect on A. baumannii biofilm formation in vitro and, to a greater extent, on biofilm maturation. In addition, FT inhibited Acinetobacter isolate-induced death of HeLa cells, which morphologically manifested as apoptosis. The mechanism of FT action on A. baumannii is currently being studied. FT may be a promising candidate for the development of a broad-spectrum anti-virulence drug to use in the prevention of nosocomial infections.

Impact of environmental cleaning on the colonization and infection rates of multidrug-resistant Acinetobacter baumannii in patients within the intensive care unit in a tertiary hospital

ObjectiveTo continuously evaluate the effect of environmental cleaning and hand hygiene compliance on the colonization and infection rates of multidrug-resistant Acinetobacter baumannii (MDR-AB) in the patients within an intensive care unit (ICU).MethodsEnvironmental cleaning on the high-touch clinical surfaces (HTCS) within a comprehensive ICU was evaluated through monitoring fluorescent marks when the overall compliance with hand hygiene during 2013–2014 was monitored. Meanwhile, samples from the HTCS and inpatients were collected and sent for bacterial culture and identification. The drug susceptibility testing was further implemented to monitor the prevalence of MDR-AB. The genetic relatedness of MDR-AB collected either from the HTCS or inpatients was analyzed by pulsed field gel electrophoresis (PFGE) when an outbreak was doubted.ResultsThe overall compliance with hand hygiene remained relatively stable during 2013–2014. Under this circumstance, the clearance rate of fluorescence marks on the environmental surfaces within ICUs significantly increased from 21.9 to 85.7%, and accordingly the colonization and infection rates of MDR-AB decreased from 16.5 to 6.6‰ and from 7.4 to 2.8‰, respectively, from the beginning to the end of 2013. However, during 2014, because of frequent change and movement of environmental services staff, the clearance rate of fluorescence marks decreased below 50.0%, and the overall colonization and infection rates of MDR-AB correspondingly increased from 9.1 to 11.1‰ and from 1.5 to 3.9‰, respectively. PFGE displayed a high genetic relatedness between the MDR-AB strains analyzed, indicating a dissemination of MDR-AB during the surveillance period.ConclusionFor the easily disseminated MDR-AB within ICUs, the clearance rate of fluorescence labeling on HTCS is negatively correlated with the hospital infection rate of MDR-AB. Such an invisible fluorescence labelling is an effective and convenient method to continuously monitor cleanness of medical environment within hospitals.

Genomic characterisation of a clinical Acinetobacter baumannii ST1928 isolate carrying a new ampC allelic variant blaADC-196 gene from China.

The prevalence of multidrug-resistant Acinetobacter baumannii is of serious concern in hospital settings. Here we report the genome sequence and genomic characterisation of a clinical A. baumannii isolate from China belonging to a novel sequence type (ST) harbouring blaOXA-383 and a new ampC allelic variant blaADC-196 simultaneously. Whole genomic DNA from A. baumannii A42 was extracted and sequenced using an Illumina HiSeq X10 platform. De novo genome assembly was performed using Unicycler, and the draft genome was annotated using the NCBI Prokaryotic Genome Annotation Pipeline. Genomic analyses were performed through various bioinformatics web servers from the Center for Genomic Epidemiology as well as BacWGSTdb. The genome size was calculated as 3 800 237bp, with 3610 protein-coding sequences and a GC content of 38.9%. A. baumannii A42 belongs to a rare sporadic clone ST1928. The resistome contains genes encoding resistance to β-lactams (blaOXA-383 and a new ampC allelic variant blaADC-196). Virulence factor genes encoding biofilm-associated protein (bap), acinetobactin biosynthesis protein (basA-J), penicillin-binding protein (pbpG) and biofilm synthesis N-glycosyltransferase (pgaA-D) as well as 16 genomic islands and multiple insertion sequences were also identified in the genome of A. baumannii A42. This is the first report of the genome sequence of an A. baumannii ST1928 clinical isolate carrying a novel class C β-lactamase gene from China. The genome sequence data can be used as a reference sequence for comparative studies and would facilitate further understanding of the antimicrobial resistance mechanisms of A. baumannii at the genomic level.

Antibiotic consumption versus the prevalence of multidrug-resistant Acinetobacter baumannii and Clostridium difficile infections at an ICU from 2014-2015.

Acinetobacter baumannii strains are currently the most commonly isolated non-fermenting rods at Polish intensive care units (ICUs), and they are the dominant aetiological agents of pneumonia. This study aimed to evaluate the prevalence of A. baumannii isolated from patients who were hospitalised at Sosnowiec Hospital's ICU. We also investigated the drug sensitivity of A. baumannii in relation to antibiotic consumption expressed as the defined daily dose (DDD) and Clostridium difficile infection (CDI). We performed a retrospective, laboratory-based study, which comprised consecutive, non-repetitive A. baumannii isolates from bloodstream infections and patients with pneumonia who were hospitalised from 2014-2015. In the analysed period, 187 A. baumannii strains constituted 13.5% of all pathogens from clinical samples. A total of 76.5% of these strains were extensively drug resistant. Resistance of A. baumannii to fluoroquinolones, amikacin, and trimethoprim/sulfamethoxazole exceeded 90%. A total of 95% of strains were resistant to imipenem and meropenem, and 100% were resistant to cephalosporins and tetracyclines. Antibiotic consumption was 191.54 DDD for 100 patient-days, and the highest use of antibiotics involved ampicillin with sulbactam. The cumulative CDI incidence rate was 2.4%. In our ICU, all of the strains were extensively drug resistant and sensitive to colistin. The significantly high consumption of carbapenems, fluoroquinolones, and aminoglycosides should be reduced because the high CDI incidence is probably related to extensive antibiotic consumption.

Highly potent antimicrobial modified peptides derived from the Acinetobacter baumannii phage endolysin LysAB2

The increase in the prevalence of multidrug-resistant Acinetobacter baumannii (MDRAB) strains is a serious public health concern. Antimicrobial peptides (AMPs) are a possible solution to this problem. In this study, we examined whether AMPs could be derived from phage endolysins. We synthesized four AMPs based on an amphipathic helical region in the C-terminus of endolysin LysAB2 encoded by the A. baumannii phage ΦAB2. These peptides showed potent antibacterial activity against A. baumannii (minimum inhibitory concentration, 4–64 μM), including some MDR and colistin-resistant A. baumannii. Of the four peptides, LysAB2 P3, with modifications that increased its net positive charge and decreased its hydrophobicity, showed high antibacterial activity against A. baumannii but little haemolytic and no cytotoxic activity against normal eukaryotic cells. The results of electron microscopy experiments and a fluorescein isothiocyanate staining assay indicated that this peptide killed A. baumannii through membrane permeabilization. Moreover, in a mouse intraperitoneal infection model, at 4 h after the bacterial injection, LysAB2 P3 decreased the bacterial load by 13-fold in ascites and 27-fold in blood. Additionally, LysAB2 P3 rescued sixty percent of mice heavily infected with A. baumannii from lethal bacteremia. Our results confirmed that bacteriophage endolysins are a promising resource for developing effective AMPs.

Elevated prevalence of multidrug-resistant Acinetobacter baumannii with extensive genetic diversity in the largest burn centre of northeast Iran.

The emergence and spread of multidrug-resistant (MDR) Acinetobacter baumannii isolates is now frequently associated with nosocomial infections. The aim of this study was to evaluate the genetic relatedness and patterns of antimicrobial resistance amongst A. baumannii isolated from a burn centre at a teaching hospital in Iran. A total of 54 A. baumannii isolates were collected from burn wound infections of hospitalised patients. Antimicrobial susceptibility of the isolates was determined, and genotyping analysis was performed by repetitive extragenic palindromic PCR (rep-PCR). PCR assay was performed to investigate the distribution of β-lactamase, aminoglycoside-modifying enzyme and efflux pump genes. Etest results revealed that the most active antimicrobial agent was colistin (100% susceptibility), followed by tigecycline (96.3%). The blaOXA-51 and blaADC genes were detected in all of the isolates, but blaOXA-58-like was not detected. The prevalence of blaTEM, blaIMP, blaVIM, blaOXA-23-like and blaOXA-24-like genes was 64.8%, 70.4%, 70.4%, 66.7% and 68.5%, respectively. ISAba1 was detected upstream of blaOXA-23-like and blaADC in 66.7% and 77.8% of isolates, respectively. This study showed a high level of distribution of adeB (72.2%), aphA6 (81.5%), aacC1 (85.2%), aadA1 (59.3%), aadB (31.5%), tetB (70.4%) and aphA1 (29.6%) in A. baumannii strains. Based on rep-PCR analysis, four clusters (I-IV) were defined. The elevated prevalence of MDR A. baumannii strains in this burn centre suggests that local antibiotic prescription policies should be precisely revised. Moreover, strict infection control procedures to prevent further dissemination need to be prioritised immediately.

Decreasing Prevalence of Multidrug-Resistant Acinetobacter Baumannii in Rīga East University Hospital / Multirezistentās Acinetobacter Baumannii Izplatības Mazināšanās Rīgas Austrumu Klīniskajā Universitātes Slimnīcā

Abstract There has been an increasing tendency of infections caused by multidrug-resistant organisms (MDRO), including multidrug-resistant Acinetobacter baumannii (MDRAB), in the Rīga East University Hospital (REUH) during the last decade. Over the last two years (2014-2015), this tendency has reversed and the prevalence of MDRAB has decreased considerably. In this study we assessed the prevalence of MDRAB in intensive care units (ICUs), internal medicine, surgery units and analysed antibiotic sensitivity profiles. In addition, we determined if current infection control measures are preventing further increase of infections caused by MDRAB in REUH. Retrospective Acinetobacter baumannii prevalence data were collected for the period from 2009 until 2012. For the time period from the beginning of 2013 until 2015, after implementing such infection control measures as control of compliance to hand hygiene guidelines, a review of central venous catheter insertion protocols and regular search for sources of MDRAB in hospital environment, prospective follow-up of new cases was conducted. Antimicrobial sensitivity profiles were assessed for the period from 2013 until 2015. Data were processed with the statistical software WHONET 5.5. Bacteria identification and antibiotic susceptibility testing were performed by VITEK 2 compact, BioMerieux, France. The prevalence of MDRAB in the period 2009 to 2013 increased from 71 to 217 cases per year, but from between 2013 (time of implementing infection control measures) and 2015 it decreased to 113 cases in 2015. In the three year period (2013-2015), the proportion of MDRAB causing bloodstream infections (BSI) and central nervous system infections (CNSI) was 15.85% from all identified MDRAB cases. Of the 113 MDRAB infections diagnosed in 2015, BSI was found in 16.81% cases (n = 19). Antibiotic resistance testing showed that colistin is the most effective drug against MDRAB. The majority of Acinetobacter baumannii isolates were resistant to Ampicillin/Sulbactam, Piperacillin/Tazobactam, Ceftazidime, Cefepime, Imipenem, Meropenem, Amikacin, Gentamicin, Tobramycin, and Ciprofloxacin. Over the last two years (2014-2015), prevalence of MDRAB infections decreased considerably. In the time period from 2013 to 2014, resistance of Acinetobacter baumannii increased to imipenem, ciprofloxacin and colistin, while decreased slightly to amikacin. Rigorous infection control measures, such as identification and elimination of new MDRAB sources in environment, review of the central venous catheter insertion protocol and improvements in hand hygiene, are crucial for decreasing distribution of and invasive infections caused by MDRAB in the hospital environment.

Multidrug resistance, inappropriate empiric therapy, and hospital mortality in Acinetobacter baumannii pneumonia and sepsis.

BackgroundThe relationship between multidrug resistance (MDR), inappropriate empiric therapy (IET), and mortality among patients with Acinetobacter baumannii (AB) remains unclear. We examined it using a large U.S. database.MethodsWe conducted a retrospective cohort study using the Premier Research database (2009–2013) of 175 U.S. hospitals. We included all adult patients admitted with pneumonia or sepsis as their principal diagnosis, or as a secondary diagnosis in the setting of respiratory failure, along with antibiotic administration within 2 days of admission. Only culture-confirmed infections were included. Resistance to at least three classes of antibiotics defined multidrug-resistant AB (MDR-AB). We used logistic regression to compute the adjusted relative risk ratio (RRR) of patients with MDR-AB receiving IET and IET’s impact on mortality.ResultsAmong 1423 patients with AB infection, 1171 (82.3 %) had MDR-AB. Those with MDR-AB were older (63.7 ± 15.4 vs. 61.0 ± 16.9 years, p = 0.014). Although chronic disease burden did not differ between groups, the MDR-AB group had higher illness severity than those in the non-MDR-AB group (intensive care unit 68.0 % vs. 59.5 %, p < 0.001; mechanical ventilation 56.2 % vs. 42.1 %, p < 0.001). Patients with MDR-AB were more likely to receive IET than those in the non-MDR-AB group (76.2 % MDR-AB vs. 13.8 % non-MDR-AB, p < 0.001). In a regression model, MDR-AB strongly predicted receipt of IET (adjusted RRR 5.5, 95 % CI 4.0–7.7, p < 0.001). IET exposure was associated with higher hospital mortality (adjusted RRR 1.8, 95 % CI 1.4–2.3, p < 0.001).ConclusionsIn this large U.S. database, the prevalence of MDR-AB among patients with AB infection was > 80 %. Harboring MDR-AB increased the risk of receiving IET more than fivefold, and IET nearly doubled hospital mortality.

Influencing factors of successful eradication of multidrug-resistant Acinetobacter baumannii in the respiratory tract with aerosolized colistin.

The increased prevalence of multidrug-resistant Acinetobacter baumannii (MDRAB) poses a worldwide treatment challenge. Although aerosolized colistin therapy for MDRAB pneumonia has attracted increasing interest, factors influencing successful eradication remain unclear. This retrospective study evaluated 135 consecutively admitted adult patients showing positive respiratory secretion cultures for MDRAB who underwent aerosolized colistin therapy between January 2007 and November 2011. Possible factors related to pneumonia and MDRAB eradication were collected for analysis. Patients with successful MDRAB eradication on Day 14 had a shorter interval between the day the positive MDRAB sputum cultures were yielded and the day colistin inhalation treatment began (4.0 ± 2.5 vs. 7.3 ± 6.5; p = 0.002). Patients with a worsening chest X-ray on Day 7 of the colistin inhalation had a lower chance of 14-day MDRAB eradication [1/44 (2.3%) vs. 8/37 (21.6%); p = 0.006]. Patients with diabetes mellitus also had a lower chance of early MDRAB eradication [13/44 (29.5%) vs. 20/37 (54.1%); p = 0.025]. Early intervention using aerosolized colistin in patients with MDRAB pneumonia or colonization can achieve better eradication.

Risk Factors for Nosocomial Infection and Mortality in Burn Patients

To evaluate the risk factors for nosocomial infection (NI) and mortality in a university hospital, 10-year data of burn patients were assessed retrospectively. The study was conducted at Erciyes University's Burn Center during 2000 and 2009. The records of 1190 patients were obtained. Overall, 131 (11%) patients had 206 NIs with an incidence density of 14.7 infections/1000 patient days. Burn wound infection (n = 109, 53%) was the most common NI. High (%TBSA burned) and late excision were found to be the most significant risk factors for the development of NI. Pseudomonas aeruginosa was the most frequent causative microorganism. However, the prevalence of multidrug-resistant Acinetobacter baumannii has increased in recent years with a prevalence of 47% in 2009. The carbapenem resistance of P. aeruginosa has decreased in recent years, whereas that of A. baumannii increased and it had a prevalence of 94% in the last year. Conversely, the most important risk factors for mortality were advanced age, high %TBSA and having an underlying disease. Prevention of NI is an important issue in burn units to reduce mortality rates. Early excision and wound closure are important therapeutic approaches for the prevention of burn wound infection.