Phenotypic and Genotypic Characteristics of Biofilm Formation in Clinical Isolates of Acinetobacter baumannii

Evaluating virulence features of Acinetobacter baumannii resistant to polymyxin B

The increasing resistance to polymyxins in Acinetobacter baumannii has made it even more urgent to develop new treatments. Anti-virulence compounds have been researched as a new solution. Here, we evaluated the modification of virulence features of A. baumannii after acquiring resistance to polymyxin B. The results showed lineages attaining unstable resistance to polymyxin B, except for Ab7 (A. baumannii polymyxin B resistant lineage), which showed stable resistance without an associated fitness cost. Analysis of virulence by a murine sepsis model indicated diminished virulence in Ab7 (A. baumannii polymyxin B resistant lineage) compared with Ab0 (A. baumannii polymyxin B susceptible lineage). Similarly, downregulation of virulence genes was observed by qPCR at 1 and 3 h of growth. However, an increase in bauE, abaI, and pgAB expression was observed after 6 h of growth. Comparison analysis of Ab0, Ab7, and Pseudomonas aeruginosa suggested no biofilm formation by Ab7. In general, although a decrease in virulence was observed in Ab7 when compared with Ab0, some virulence feature that enables infection could be maintained. In light of this, virulence genes bauE, abaI, and pgAB showed a potential relevance in the maintenance of virulence in polymyxin B-resistant strains, making them promising anti-virulence targets.

Medical Device-Associated Biofilm Infections and Multidrug-Resistant Pathogens

Medical devices such as venous catheters (VCs) and urinary catheters (UCs) are widely used in the hospital setting. However, the implantation of these devices is often accompanied by complications. About 60 to 70% of nosocomial infections (NIs) are linked to biofilms. The main complication is the ability of microorganisms to adhere to surfaces and form biofilms which protect them and help them to persist in the host. Indeed, by crossing the skin barrier, the insertion of VC inevitably allows skin flora or accidental environmental contaminants to access the underlying tissues and cause fatal complications like bloodstream infections (BSIs). In fact, 80,000 central venous catheters-BSIs (CVC-BSIs)-mainly occur in intensive care units (ICUs) with a death rate of 12 to 25%. Similarly, catheter-associated urinary tract infections (CA-UTIs) are the most commonlyhospital-acquired infections (HAIs) worldwide.These infections represent up to 40% of NIs.In this review, we present a summary of biofilm formation steps. We provide an overview of two main and important infections in clinical settings linked to medical devices, namely the catheter-asociated bloodstream infections (CA-BSIs) and catheter-associated urinary tract infections (CA-UTIs), and highlight also the most multidrug resistant bacteria implicated in these infections. Furthermore, we draw attention toseveral useful prevention strategies, and advanced antimicrobial and antifouling approaches developed to reduce bacterial colonization on catheter surfaces and the incidence of the catheter-related infections.

Molecular characteristics and biofilm formation capacity of nontypeable Haemophilus influenza strains isolated from lower respiratory tract in children

With the widespread introduction of the Hib conjugate vaccine, Nontypeable Haemophilus influenzae (NTHi) has emerged as the predominant strain globally. NTHi presents a significant challenge as a causative agent of chronic clinical infections due to its high rates of drug resistance and biofilm formation. While current research on NTHi biofilms in children has primarily focused on upper respiratory diseases, investigations into lower respiratory sources remain limited. In this study, we collected 54 clinical strains of lower respiratory tract origin from children. Molecular information and drug resistance features were obtained through whole gene sequencing and the disk diffusion method, respectively. Additionally, an in vitro biofilm model was established. All clinical strains were identified as NTHi and demonstrated the ability to form biofilms in vitro. Based on scanning electron microscopy and crystal violet staining, the strains were categorized into weak and strong biofilm-forming groups. We explored the correlation between biofilm formation ability and drug resistance patterns, as well as clinical characteristics. Stronger biofilm formation was associated with a longer cough duration and a higher proportion of abnormal lung imaging findings. Frequent intake of β-lactam antibiotics might be associated with strong biofilm formation. While a complementary relationship between biofilm-forming capacity and drug resistance may exist, further comprehensive studies are warranted. This study confirms the in vitro biofilm formation of clinical NTHi strains and establishes correlations with clinical characteristics, offering valuable insights for combating NTHi infections.

Genotypic and phenotypic mechanisms underlying antimicrobial resistance and synergistic efficacy of rifampicin-based combinations against carbapenem-resistant Acinetobacter baumannii

Purpose

Carbapenem-resistant Acinetobacter baumannii (CRAB) is an urgent concern to public health. This study focuses on exploring the resistance mechanisms and the in vitro results of using rifampicin in combination with conventional antibiotics for the management of CRAB.

Methods

The synergistic and bactericidal effects of rifampicin with conventional antibiotics were evaluated using chequerboard assay and time-kill assay, while the phenotypic and genotypic characteristics of resistant determinants were performed by efflux pump detection and whole genome sequencing on 29 isolates from ICU patients with underlying health diseases.

Results

The isolates showed multidrug resistance, with over 60% showing addictive responses to rifampicin-based combinations at FICI ranging from 0.6 to 0.8. The time-kill assay revealed 99 % killing for rifampicin and minocycline combination in one isolate at 1/4 MIC rifampicin plus 1/4 MIC minocycline, while a bacteriostatic effect was observed at 1/2 MIC rifampici plus 1/2 MIC for a second isolate. Combination with tigecycline resulted in a 99% killing in two out of three isolates with a 2.5-3 log reduction in CFU at 1/4 MIC rifampicin plus 1/4 MIC tigecycline. Rifampicin plus colistin exhibited bactericidal activity against three out of four isolates. The combinations of rifampicin with ciprofloxacin, chloramphenicol, and trimethoprim-sulfamethoxazole were ineffective against the isolates. In addition, a 4-fold reduction in rifampicin MIC was observed in 2 out of 14 isolates in the presence of an efflux pump inhibitor. The pan-genome study demonstrated a progressive evolution with an accessory genome estimated to cover 58% of the matrix. Seven of the ten sequenced isolates belong to sequence type 2 (ST2), while one isolate each was assigned to ST164, ST16, and ST25. Furthermore, 11 plasmids, 34 antimicrobial resistance (AMR) genes, and 65 virulence-associated genes were predicted from the whole genome data. The blaOXA-23blaADC-25, blaOXA-66, blaPER-7, aph(6)-Id, armA, and arr-3 were prevalent among the isolates. Sequence alignment of the bacteria genome to the reference strain revealed a deleterious mutation in the rpoB gene of 4 isolates.

Conclusion

The study suggests that rifampicin in combination with either minocycline, tigecycline, or colistin might be a treatment option for CRAB clinical isolates. In addition, genotypic analysis of the bacteria isolates may inform the clinician of the suitable drug regimen for the management of specific bacteria variants.

Analysis of carbapenem-resistant Acinetobacter baumannii carbapenemase gene distribution and biofilm formation

OBJECTIVE

In recent years, Acinetobacter baumannii has been appearing in hospitals with high drug resistance and strong vitality, which brings many difficulties to clinical treatment. In this study, 255 strains of A. baumannii were isolated from Youjiang Medical University for Nationalities Affiliated Hospital clinical samples and found to be highly resistant to carbapenems. The drug resistance, biofilm-forming ability, and carbapenase gene distribution of 145 carbapenem-resistant A. baumannii (CRAB) strains were analyzed statistically.

METHODS

The clinically isolated strains were detected using Vitek mass spectrometry and Vitek2-compact for bacterial identification and susceptibility testing, respectively. The biofilms of clinical isolates were quantitatively detected by microplate crystal violet staining, and qualitatively observed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). And the common carbapenemase genes were detected by polymerase chain reaction (PCR).

RESULTS

The 255 clinical isolates from the Youjiang District of western Guangxi Province had a high resistance rate to carbapenems antibiotics. The main specimens were from the intensive care unit (49%), and the most important specimens were sputum specimens (80%). All 145 strains of CRAB produced different degrees of biofilm, and six carbapenenase genes were detected. We found that there were significant differences in biofilm formation between resistant and sensitive strains of tobramycin, levofloxacin, ciprofloxacin, tigecycline, and doxycycline (P<0.05). The distribution of blaOXA-23 and blaOXA51 genes was significantly different from CRAB biofilm formation (P<0.05). In addition, AmpC, blaOXA-23, blaOXA-51, and TEM genes were more distributed in antibiotic-resistant strains.

CONCLUSION

The clinical strains have a high resistance rate to carbapenems, and the CRAB with blaOXA-51 and blaOXA-23 genes has a high resistance to antibiotics and a strong biofilm.

Sub-minimum inhibitory concentrations (sub-MICs) of colistin on Acinetobacter baumannii biofilm formation potency, adherence, and invasion to epithelial host cells: an experimental study in an Iranian children's referral hospital

Here, we described the efficacy of colistin sub-minimum inhibitory concentrations (sub-MICs) on biofilm-forming activity, host epithelial cell adherence, and invasion capacity of Acinetobacter baumannii strains collected from children admitted to the Children's Medical Center Hospital. Biofilm formation potency of A. baumannii clinical isolates was measured using a 96-well microtiter plate assay. Distribution of biofilm-related genes, including bap, abaI, ompA, csuE, and blaPER-1, was detected by PCR. The mRNA expression level of ompA and csuE was measured by qPCR in the presence of ¼ and ½ MICs of colistin. A. baumannii adhesion and invasion to eukaryotic host cells were phenotypically assayed at sub-MICs of colistin. Eighty percent (56/70) and 35.7% (25/70) of A. baumannii isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR) phenotypes, respectively. The strong, moderate, and weak biofilm producers of A. baumannii were 37.1% (26/70), 32.8%, (23/70), and 22.8% (16/70), respectively. The frequencies of biofilm-associated genes were 100% for abaI, ompA, and csuE, followed by 22.8% (16/70) and 24.3% (17/70) for bap and blaPER-1, respectively. The downregulation of csuE and ompA expression levels was observed in the sub-MIC of colistin. In vitro cell culture study showed a decreased capability of A. baumannii to adhere to the human epithelial cells at sub-inhibitory doses of colistin; however, none of the isolates could invade HEp-2 cells. Our study showed that the genes encoding biofilm-associated proteins undergo downregulation in expression levels after exposure to sub-MICs of colistin in A. baumannii. Longitudinal in vivo studies are needed to fully understand the clinical aspects of pathogenicity mechanisms and evolutionary dynamics of drug resistance.IMPORTANCESince the toxicity of colistin is dose dependent, there is a focus on strategies that reduce the dose while maintaining the therapeutic effect of the drug. Our findings about sub-inhibitory doses of colistin provide a novel insight into the logical use of colistin to treat and control Acinetobacter baumannii-related infections in clinical practice.

Prevalence of biofilm producing Acinetobacter baumannii clinical isolates: A systematic review and meta-analysis

BACKGROUND

Acinetobacter baumannii, the first human pathogen to be designated as a "red-alert" pathogen, is on the critical priority list of pathogens requiring new antibiotics. Biofilm-associated diseases are the most common infections caused by the antibiotic-resistant bacteria A. baumannii. Multidrug-resistant strains are more easily transmitted around the world due to A. baumannii's ability to produce biofilms, which allows it to develop antibiotic resistance mechanisms and thrive in healthcare environments. As a result, A. baumannii infections are becoming increasingly common in hospital settings allover the world. As a result, a comprehensive systematic review and meta-analysis were carried out to determine the global prevalence of biofilm-producing A. baumannii clinical isolates.

METHODS

Articles were extensively searched in bibliographic databases and grey literatures using entry terms or phrases. Studies meeting eligibility criteria were extracted in MS Excel and exported into STATA version 12 software for statistical analysis. A random-effects model was used to compute the pooled prevalence of biofilm-producing A. baumannii clinical isolates. The heterogeneity was quantified by using the I2 value. Publication bias was assessed using a funnel plot and Egger's test. Sensitivity analysis was done to assess the impact of a single study on pooled effect size.

RESULT

Of the 862 studies identified, 26 studies consisted of 2123 A.baumannii clinical isolates of which 1456 were biofilm-producing. The pooled prevalence of biofilm-producing A.baumannii clinical isolates was 65.63% (95% CI = 56.70%-74.56%). There was substantial heterogeneity with an I2 value of 98.1%. Moreover, 41.34%, 33.57%, and 27.63% of isolates of strong, mild, and weak producers of biofilm. Higher prevalence was found in studies published after 2014 (66.31%); Western Pacific region (76.17%); and Asia (66.22%) followed by the African continent (57.29%).

CONCLUSION

The pooled prevalence of biofilm-producing A. baumannii clinical isolates has risen alarmingly, posing a public health risk. This indicates the burden of biofilm-producing A. baumannii infections urges routine screening and appropriate treatment for better management of hospitalized patients, as well as effective controlling of the emergence of drug resistance. Furthermore, this finding is an alert call for the stakeholders to develop strong infection prevention and antibiotics stewardship programs for the prevention and control of biofilm-producing bacterial infections.

Antibacterial Activity of Surfactin and Synergistic Effect with Conventional Antibiotics Against Methicillin-Resistant Staphylococcus aureus Isolated from Patients with Diabetic Foot Ulcers

Introduction

The prevalence of diabetic foot ulcers (DFUs) is increasing, leading to a huge financial burden and human suffering. Furthermore, antibiotic resistance is an urgent problem in the realm of clinical practice. Antimicrobial peptides are an effective and feasible strategy for combating infections caused by drug-resistant bacteria. Therefore, we investigated the in vitro antimicrobial ability of the lipopeptide surfactin, either alone or in combination with conventional antibiotics, against the standard and clinical strains of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), isolated from patients with DFUs.

Methods

The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of surfactin on the selected strains were evaluated by a microbroth dilution technique. The growth curves of the selected strains with and without surfactin were measured, and transmission electron microscopy was used to observe the structure of surfactin-treated bacterial cells. The biofilm inhibitory abilities of surfactin were assessed by crystal violet staining. The antimicrobial interactions between surfactin and conventional antibiotics were established using a checkerboard assay, as well as determining the mutant prevention concentration. The inhibitory effect of surfactin on penicillinase was tested by iodometry.

Results

The MIC and MBC values of surfactin ranged from 512 to 1024 µg/mL and 1024 to 2048 µg/mL, respectively. Moreover, surfactin significantly prevented the S. aureus biofilm formation and displayed limited toxicity on human red blood cells. The synergies between surfactin and ampicillin, oxacillin, and tetracycline against S. aureus were revealed. In vitro resistance was not readily produced by surfactin. The action of surfactin may be by disrupting bacterial cell membranes and inhibiting penicillinase.

Conclusion

Surfactin appears to be a potential option for the treatment of DFUs infected with MRSA, as it is capable of improving antimicrobial activities and can be used alone or in combination with conventional antibiotics to prevent or postpone the emergence of resistance.

Antibacterial activity of silver nanoparticles functionalized with amikacin applied against multidrug-resistant acinetobacter baumannii

BACKGROUND

Multidrug-resistant bacteria are one of the world's biggest health problems; therefore, improving the spectrum of action of antibiotics could be necessary to reverse this situation. Amikacin and silver salts have well-known antimicrobial properties. However, both drugs lost their effectiveness against some bacteria, such as Acinetobacter baumannii. This work aims to develop a nanodrug from silver nanoparticles (AgNPs) functionalized with Amikacin against multidrug-resistant Acinetobacter baumannii.

METHODS

AgNPs were produced using the bottom-up methodology and functionalized with Amikacin modified by the carbodiimide-based chemistry, forming AgNPs@Amikacin. Susceptibility tests were performed using Amikacin-resistant Acinetobacter baumannii strains to assess the bacteriostatic and bactericidal potential of the developed nanodrug. The clinical strains were induced to form a biofilm, and biomass quantification and the metabolic activity were determined.

RESULTS

The AgNPs have a hydrodynamic diameter of the particles with a bimodal distribution, with a size of 37.84 nm. The FT-IR spectrum of AgNPs@Amikacin exhibits vibrational modes corresponding to Amikacin, confirming the conjugation to AgNPs. Susceptibility testing demonstrated a minimal inhibitory and bactericidal concentration of < 0.5 µg/mL. The AgNPs@Amikacin reduced the biofilm metabolic activity of Acinetobacter baumannii at rates ≥ 50%, characterized by the minimal biofilm inhibition concentrations.

CONCLUSIONS

Results demonstrate a promising development of a new nanodrug with lower concentrations, less toxicity, and greater efficacy against multidrug-resistant Acinetobacter baumannii.

Acinetobacter baumannii Biofilm Formation: Association with Antimicrobial Resistance and Prolonged Survival under Desiccation

Biofilm-forming multidrug-resistant Acinetobacter baumannii has emerged as a global pathogen. This study investigated the impact of biofilm formation by A. baumannii on antimicrobial resistance and prolonged survival under desiccation, which is essential for effective infection control of A. baumannii in hospital settings. Seventy-eight clinical isolates of A. baumannii were identified, and antibiotic susceptibility profiles were assessed. All the isolates were investigated for their biofilm-forming abilities at 24 and 48 h. The biofilm inhibitory concentrations of antibiotics were evaluated for selected biofilm-forming isolates to determine the influence of biofilm on antibiotic tolerance. The impact of biofilm formation on desiccation tolerance was also evaluated for up to 48 days. The results revealed that out of 78 A. baumannii clinical isolates, 83% were MDR and 17% non-MDR. Overall, 79% of isolates formed high biofilm after 24 h. The extent of biofilm formation gets significantly increased after 48 h, and 87% of isolates formed high biofilm. It was observed that eradicating mature biofilm requires up to a thousandfold higher concentration of antibiotics than MICs, and biofilm-forming isolates can survive for a prolonged period under desiccation. In conclusion, our findings revealed that both MDR and non-MDR isolates of A. baumannii could form biofilms on abiotic surfaces. A. baumannii biofilms contribute to endurance in the presence of antimicrobials and desiccation conditions, which are significant trouble for hospital patient care management. The present findings may offer insights for developing preventive measures to tackle biofilm-associated A. baumannii infection.

Virulence Characteristics and Emerging Therapies for Biofilm-Forming Acinetobacter baumannii: A Review

Simple Summary

Acinetobacter baumannii (A. baumannii) is one of the ESKAPE organisms and has the competency to build biofilms. These biofilms account for the most nosocomial infections all over the world. This review reflects on the various physicochemical and environmental factors such as adhesion, pili expression, growth surfaces, drug-resistant genes, and virulence factors that profoundly affect its resistant forte. Emerging drug-resistant issues and limitations to newer drugs are other factors affecting the hospital environment. Here, we discuss newer and alternative methods that can significantly enhance the susceptibility to Acinetobacter spp. Many new antibiotics are under trials, such as GSK-3342830, The Cefiderocol (S-649266), Fimsbactin, and similar. On the other hand, we can also see the impact of traditional medicine and the secondary metabolites of these natural products’ application in searching for new treatments. The field of nanoparticles has demonstrated effective antimicrobial actions and has exhibited encouraging results in the field of nanomedicine. The use of various phages such as vWUPSU and phage ISTD as an alternative treatment for its specificity and effectiveness is being investigated. Cathelicidins obtained synthetically or from natural sources can effectively produce antimicrobial activity in the micromolar range. Radioimmunotherapy and photodynamic therapy have boundless prospects if explored as a therapeutic antimicrobial strategy.

Abstract

Acinetobacter species is one of the most prevailing nosocomial pathogens with a potent ability to develop antimicrobial resistance. It commonly causes infections where there is a prolonged utilization of medical devices such as CSF shunts, catheters, endotracheal tubes, and similar. There are several strains of Acinetobacter (A) species (spp), among which the majority are pathogenic to humans, but A. baumannii are entirely resistant to several clinically available antibiotics. The crucial mechanism that renders them a multidrug-resistant strain is their potent ability to synthesize biofilms. Biofilms provide ample opportunity for the microorganisms to withstand the harsh environment and further cause chronic infections. Several studies have enumerated multiple physiological and virulence factors responsible for the production and maintenance of biofilms. To further enhance our understanding of this pathogen, in this review, we discuss its taxonomy, pathogenesis, current treatment options, global resistance rates, mechanisms of its resistance against various groups of antimicrobials, and future therapeutics.

Phenotypic and Genotypic Characteristics of a Tigecycline-Resistant Acinetobacter pittii Isolate Carrying bla NDM-1 and the Novel bla OXA Allelic Variant bla OXA-1045

A tigecycline-resistant Acinetobacter pittii clinical strain from pleural fluid carrying a bla_NDM–1 gene and a novel bla_OXA gene, bla_OXA–1045, was isolated and characterized. The AP2044 strain acquired two copies of the bla_NDM–1 gene and six antibiotic resistance genes (ARGs) from other pathogens. According to the whole-genome investigation, the GC ratios of ARGs (50–60%) were greater than those of the chromosomal backbone (39.46%), indicating that ARGs were horizontally transferred. OXA-1045 belonged to the OXA-213 subfamily and the amino acid sequence of OXA-1045 showed 89% similarity to the amino acid sequences of OXA-213. Then, bla_OXA–1045 and bla_OXA–213 were cloned and the minimum inhibitory concentrations (MICs) of β-lactams in the transformants were determined using the broth microdilution method. OXA-1045 was able to confer a reduced susceptibility to piperacillin and piperacillin-tazobactam compared to OXA-213. AP2044 strain exhibited low pathogenicity in Galleria mellonella infection models. The observation of condensed biofilm using the crystal violet staining method and scanning electron microscopy (SEM) suggested that the AP2044 strain was a weak biofilm producer. Quantitative reverse transcription-PCR (qRT-PCR) was used to detect the expression of resistance-nodulation-cell division (RND) efflux pump-related genes. The transcription level of adeB and adeJ genes increased significantly and was correlated with tigecycline resistance. Therefore, our genomic and phenotypic investigations revealed that the AP2044 strain had significant genome plasticity and natural transformation potential, and the emergence of antibiotic resistance in these unusual bacteria should be a concern for future investigations.

Pathogenic Characteristics and Risk Factors for ESKAPE Pathogens Infection in Burn Patients

Objective

This study aimed to determine the clinical manifestations, antimicrobial resistance, molecular characteristics, and risk factors for ESKAPE pathogens infection in burn patients.

Methods

A retrospective study of 187 burn patients infected with ESKAPE pathogens was conducted at the Department of Plastic and Burn Surgery of the Affiliated Hospital of Southwest Medical University (Luzhou, China) from October 2018 to June 2021. All strains were identified using a MicroScan WalkAway 96 Plus System, and antimicrobial susceptibilities were determined using the VITEK system or the disk diffusion method. The antimicrobial resistance genes of multi-drug resistant ESKAPE (MDR-ESKAPE) were detected by polymerase chain reaction (PCR). The multivariable logistic regression analysis was used to estimate the risk factors for ESKAPE infection and MDR-ESKAPE infection.

Results

A total of 255 strains were isolated in various types of clinical specimens from 187 burn patients, of which 47.5% were ESKAPE pathogens (121/255). Among these, MDR-ESKAPE pathogens accounted for 55% (67/121). Additionally, aph3ʹIII, mecA, bla_SHV, bla_TEM, bla_PDC, and bla_SHV were the most prevalent genes detected in Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp., respectively. The independent risk factors for ESKAPE infection were total body surface area (TBSA) >30–50% (odds ratio [OR] = 10.428; 95% confidence interval [CI], 2.047 to 53.108), TBSA >50% (OR = 15.534; 95% CI, 1.489 to 162.021), and parenteral nutrition (OR = 3.597; 95% CI, 1.098 to 11.787). No independent risk factors were found for MDR-ESKAPE infection.

Conclusion

Clinical staff should be alert to the risk of nosocomial infection with ESKAPE pathogens in burn patients receiving parenteral nutrition and under TBSA >30%. Full attention should also be paid to the ESKAPE resistance, strict adherence to infection control protocols for the rational use of antimicrobial agents, and enhanced clinical standardization of antimicrobial agents management.

Multidrug Resistant Acinetobacter baumannii Biofilms: Evaluation of Phenotypic-Genotypic Association and Susceptibility to Cinnamic and Gallic Acids

Acinetobacter baumannii armed with multidrug resistance (MDR) and biofilm-forming ability is increasingly recognized as an alarming pathogen. A deeper comprehension of the correlation between these two armories is required in circumventing its infections. This study examined the biofilm-forming ability of the isolates by crystal violet staining and the antibiotic susceptibility by broth microdilution method. The genetic basis of the MDR and biofilm-forming phenotypes was screened by polymerase chain reaction. The antimicrobial activities of cinnamic and gallic acids against planktonic cells and biofilms of A. baumannii were investigated, and the findings were confirmed with scanning electron microscopy (SEM). Among 90 A. baumannii isolates, 69 (76.6%) were MDR, and all were biofilm formers; they were classified into weak (12.2%), moderate (53.3%), and strong (34.5%) biofilm formers. Our results underlined a significant association between MDR and enhanced biofilm formation. Genotypically, the presence of bla_VIM and bla_OXA–23 genes along with biofilm-related genes (ompA, bap, and csuE) was statistically associated with the biofilm-forming abilities. Impressively, both gallic and cinnamic acids could significantly reduce the MDR A. baumannii biofilms with variable degrees dependent on the phenotype–genotype characteristics of the tested isolates. The current findings may possess future therapeutic impact through augmenting antimicrobial arsenal against life-threatening infections with MDR A. baumannii biofilms.