scholarly journals Acinetobacter baumannii: Identification, Antibiotic Sensitivity and Biofilm Formation in Different Clinical Samples

2018 ◽  
Vol 12 (2) ◽  
pp. 4-9
Author(s):  
Maherun Nesa ◽  
Shaheda Anwar ◽  
Ahmed Abu Saleh

Background: Acinetobacter baumannii is responsible for nosocomial infections which are related to biofilm formation of this pathogen. Biofilm formation helps the bacteria in surviving stressed environmental conditions and bacteria growing in biofilms are resistant to most of the commonly used antibiotics. Objectives: The objective of this study was to detect A. baumannii, to see antibiotic sensitivity and biofilm formation in different clinical samples. Methods: Total 108 Acinetobacter spp. were collected from different clinical samples which were identified by conventional microbiological procedures. Out of 108 Acinetobacter spp, 85 were identified as A. baumannii by polymerase chain reaction by detecting blaOXA-51 gene which is intrinsic to A. baumannii. Antibiotic sensitivity was detected by modified disc diffusion method and biofilm formation was detected by Tissue culture plate method. Results: Among 85 isolates, 45.9% A. baumannii were obtained from tracheal aspirate followed by blood (21.2%), wound swab (15.3%), urine (10.6%), pus (5.9%) and pleural fluid (1.1%). More than 80% 0f A. baumannii was resistant to cephalosporin, aminoglycosides, quinolone, carbapenem. By Tissue culture plate method, 78.8% of isolates showed biofilm formation. Biofilm formation in tracheal aspirate was 82.1%, in blood 72%, in wound swab 92%, in urine 44.4%, in pus 100% and in pleural fluid 100%. Conclusion: Detection rate of A. baumannii was more in tracheal aspirates. Biofilm producing A. Baumannii was resistant to most of the antibiotics. Bangladesh J Med Microbiol 2018; 12 (2): 4-9

Author(s):  
Bedobroto Biswas ◽  
Naik Shalini Ashok ◽  
Deepesh Nagarajan ◽  
Md Zaffar Iqubal

Aims: Identification and grading of the Escherichia coli according to their biofilm production capability. Study Design:  Cross-sectional study. Place and Duration of Study: This was conducted in Department Microbiology at M.S. Ramaiah Medical college and Hospital, Bengaluru from March 2017 to August 2017. Methodology: A total of 55 non repetitive Escherichia coli isolates were identified from various clinical samples like urine, pus ,tissue and peritoneal fluids .All the organisms were isolated in pure culture and biofilm formation was detected in vitro by Gold standard TCP (Tissue culture plate) method. Organisms were incubated for an extended period of 48 hours and the biofilms were detected by acetone alcohol elution method. Organisms were categorized as strong, moderate, weak and no biofilm producers based on the obtained OD value of the elute. Results: Majority of the isolates of Escherichia coli were obtained from catheterized urine culture (67.03%) followed by pus (25.50%).Most of the isolates were capable of forming biofilm in vitro by tissue culture plate method except a few (9.1%). 40% of the isolates were strong biofilm formers which had >4 ODC. 25.5% showed medium biofilm-forming capability and rest 25.5% showed weak biofilm formations in vitro. Conclusion: The ability to form biofilm from a species can give us a better understanding of the biofilm-related infections pertaining to the particular group. Detection of biofilms remains a most important determinant to approximate the incidence of such infections. Categorization of organisms according to their biofilm formation may help us understand the frequency of biofilm-associated infections, and thus take necessary precautions to avoid the problem. Further studies involving the detection of biofilm may be conducted and the tests can be implemented in routine diagnostic microbiology to assess the usefulness of the methods in detection of biofilm-related infections.


2021 ◽  
Vol 13 (4) ◽  
pp. 1043-1052
Author(s):  
Sarita Manandhar ◽  
Raju Shrestha ◽  
Ratna Shova Tuladhar ◽  
Sunil Lekhak

Resistance to antibiotics, biofilm formation and the presence of virulence factors play important roles in increased mortality associated with infection by staphylococci. The macrolide lincosamide streptogramin B (MLSB) family of antibiotics is commonly used to treat infections by methicillin-resistant isolates. Clinical failure of clindamycin therapy has been reported due to multiple mechanisms that confer resistance to MLSB. This study aims to find the incidence of different phenotypes of MLSB resistance and biofilm production among staphylococci. A total of 375 staphylococci were isolated from different clinical samples, received from two tertiary care hospitals in Nepal. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by D test, according to CLSI guidelines. Biofilm formation was detected by the tissue culture plate method and PCR was used to detect ica genes. Of the total staphylococci isolates, 161 (42.9%) were Staphylococcus aureus, with 131 (81.4%) methicillin-resistant strains, and 214 (57.1%) isolates were coagulase-negative staphylococci, with 143 (66.8%) methicillin-resistant strains. The overall prevalence of constitutive MLSB (cMLSB) and inducible MLSB (iMLSB) phenotypes was 77 (20.5%) and 87 (23.2%), respectively. Both iMLSB and cMLSB phenotypes predominated in methicillin-resistant isolates. The tissue culture plate method detected biofilm formation in 174 (46.4%) isolates and ica genes in 86 (22.9%) isolates. Among biofilm producing isolates, cMLSB and iMLSB phenotypes were 35 (20.1%) and 27 (15.5%), respectively. The cMLSB and iMLSB were 11 (12.8%) and 19 (22.1%), respectively, in isolates possessing ica genes. Clindamycin resistance in the form of cMLSB and iMLSB, especially among MRSA, emphasizes the need for routine D tests to be performed in the lab.


2020 ◽  
Vol 56 (2) ◽  
pp. 118
Author(s):  
Wira W Lindarto ◽  
Eddy Bagus Wasito ◽  
Kartuti Debora

This study aimed to analyze the effect of glucose induction on the clinical isolate biofilm density of Acinetobacter baumannii. Thirteen clinical isolates of A. baumannii non biofilm forming were collected from non-DM patients who were treated at the ICU of Dr. Soetomo Hospital, Surabaya, was treated with the addition of 0.08% glucose, 0.15% glucose, 0.2% glucose, and 0.4% glucose in TSB growth media, followed by biofilm density examination with Tissue Culture Plate Method (TCPM) using 96 wells flatbottomed polyesterene tissue culture plate and read by autoreader ELISA with a wavelength of 630 nm (OD630). Biofilm density obtained was analyzed using ANOVA statistical analysis. The results of OD630 showed that the biofilm density increased significantly at the addition of 0.2% and 0.4% glucose. There was a significant increase in biofilm density at the addition of 0.2% and 0.4% glucose so that the management of blood sugar levels in ICU patients was needed before and when medical devices were installed.


Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 630 ◽  
Author(s):  
Aisha M. Alamri ◽  
Afnan A. Alsultan ◽  
Mohammad A. Ansari ◽  
Amani M. Alnimr

This study analyzed the genotype, antibiotic resistance, and biofilm formation of Acinetobacter baumannii strains and assessed the correlation between biofilm formation, antibiotic resistance, and biofilm-related risk factors. A total of 207 non-replicate multi-drug-resistant A. baumannii strains were prospectively isolated. Phenotypic identification and antimicrobial susceptibility testing were carried out. Isolate biofilm formation ability was evaluated using the tissue culture plate (TCP), Congo red agar, and tube methods. Clonal relatedness between the strains was assessed by enterobacterial repetitive intergenic consensus-PCR genotyping. Of the 207 isolates, 52.5% originated from an intensive care unit setting, and pan resistance was observed against ceftazidime and cefepime, with elevated resistance (99–94%) to piperacillin/tazobactam, imipenem, levofloxacin, and ciprofloxacin. alongside high susceptibility to tigecycline (97.8%). The Tissue culture plate, Tube method, and Congo red agar methods revealed that 53.6%, 20.8%, and 2.7% of the strains were strong biofilm producers, respectively, while a significant correlation was observed between biofilm formation and device-originating respiratory isolates (p = 0.0009) and between biofilm formation in colonized vs. true infection isolates (p = 0.0001). No correlation was detected between antibiotic resistance and biofilm formation capacity, and the majority of isolates were clonally unrelated. These findings highlight the urgent need for implementing strict infection control measures in clinical settings.


Author(s):  
Mayuri Gogoi ◽  
Ajanta Sharma

Background: The purpose of this study was to detect biofilm formation by bacterial isolates from patients with device associated infection admitted in intensive care units (ICUs), to compare the three methods used for detection of bioiflm, to compare the antimicrobial susceptibility pattern of the biofilm producers with the non-producers and to study the risk factors associated with biofilm formation.Methods: A total of 115 bacterial isolates from patients with device associated infection admitted in different ICU for a period of one year was included in the study. These clinical isolates were detected for biofilm formation by tissue culture plate method, tube method and Congo red agar method. Kirby-Bauer disc diffusion method of antibiotic susceptibility was performed on all isolates.Results: Out of the 115 bacterial isolates, 71 were biofilm producers. Tissue culture plate method detected the maximum number of biofilm producers (61.7%). The maximum number of biofilm producers were isolated from tracheal aspirate and endotracheal tubes (52.1%) followed by blood (17%) and urine (12.6%) respectively. The predominant biofilm producing isolates were Klebsiella pneumoniae (39.4%), Staphylococcus aureus (19.7%) and Pseudomonas aeruginosa (16.9%). Multi drug resistance among the biofilm producers was significantly higher than the non-biofilm producers (p value=0.0125). The risk of biofilm formation was seen to increase with the increase in duration of hospital stay (p value=0.0092, statistically very significant).Conclusions: From this study it was found that a high degree of biofilm producers were isolated from patients on indwelling devices. Tissue culture plate was found to be the most accurate method. The degree of multidrug resistance among the bioiflm producers was significantly higher than the non-producers.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Upasana Ghimire ◽  
Rupesh Kandel ◽  
Mary Neupane ◽  
Sanjit Shrestha ◽  
Sudeep K C ◽  
...  

(1) Background: Acinetobacter baumannii has emerged as a leading cause of nosocomial infections as they are capable of evolving resistance to various classes of antibiotics. The ability of A. baumannii to form biofilm might also be associated with increased antibiotic resistance and hence treatment failure. This study was carried to associate the biofilm formation with the drug resistance pattern of A. baumannii and to detect blaOXA-23, blaOXA-24, and blaOXA-51 from carbapenem resistance isolates. (2) Methods: Among different clinical samples, a total of 19 Acinetobacter spp. were identified with conventional microbiological procedures. The biofilm production was determined by a quantitative adherence assay. The antimicrobial susceptibility test was carried out by the Kirby-Bauer disc diffusion method, carbapenemase production detection was confirmed by Modified Hodge Test. And target resistant genes were detected by polymerase chain reaction. (3) Results: Out of 90 clinical specimens, 64.44% (58/90) showed bacterial growth. Whereas, 32.75% (19/58) isolates were identified as A. baumannii. Among all A. baumannii isolates, 84.21% (16/19) were multidrug-resistance and 63.16% (12/19) carbapenem resistance phenotypically. blaOXA-51 was detected in all the isolates and blaOXA-23 was detected only in 63.16% (12/19) isolates. However, blaOXA-24 was not detected in any of the isolates. Among A. baumannii, 89.47% (17/19) isolates produced biofilm with 47.37% (9/19) strong biofilm producers. (4) Conclusions: In the majority of MDR A. baumannii, blaOXA-51 and blaOXA-23 were detected as the determinant factor for carbapenem resistance having a direct relation with biofilm formation. This study provided a valuable clue for the management of A. baumannii infections in clinical settings.  


2019 ◽  
Vol 18 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Mahesh Prakash Bhatta ◽  
Asmita Sapkota ◽  
Pushpa Subedi ◽  
Sunita Baniya Chhetri ◽  
Dhaka Raj Pant ◽  
...  

Introduction: Urinary tract infection (UTI) is the most common health care associated infection caused by various pathogenic bacteria. Biofilms are communities of bacteria that are held together by exopolymeric substances that protect against the antimicrobial therapy and other environmental assaults. The aim of this study was to estimate the prevalence of biofilm forming bacteria in Nepalese population and to study the emergence of antimicrobial resistance among biofilm producing bacteria in comparison to non-biofilm producing bacteria. Methods: A total of 785 clean-caught-mid-stream urine samples were collected. After isolation and identification of uropathogens, they were further processed for detection of biofilm formation by two methods (Congo Red Agar method and Tissue Culture Plate method) as well as for antibiotic sensitivity test. Results: Out of total collected samples, 12.74% were found to be associated with UTI, among them 67% were Escherichia coli, 10% were Klebsiella spp, 7% were Pseudomonas spp, 6% were Staphyloccous aureus, 4% were Enterobacter spp, 3% were Proteus spp, 2% were Citrobacter spp and remaining 1% was Staphylococcus saprophyticus. Among isolated organisms, the ratio of bioflim positive organism to bioflim negative organism was found to be 9:11. Nitrofurantoin, Tobramycin, Chloramphenicol, Amikacin and Imipenem were found to be significantly more sensitive in biofilm negative bacteria as compared to biofilm positive bacteria with p values of 0.000, 0.001, 0.000, 0.000 and 0.001. Conclusions: The prevalence rate of multidrug resistance in bacterial uropathogens was higher in biofilm producers as compared to non-biofilm producers. Biofilm forming characteristic of bacteria make them more resistant to antibiotics.


2018 ◽  
Vol 33 (3) ◽  
pp. 80-85
Author(s):  
Michael O. Osungunna ◽  
Grace O. Onawunmi

Background: Microorganisms that infect humans differ in pathogenesis, virulence factors and antimicrobial resistance profiles. In natural settings, bacterial cells are most often found in close association with surfaces and interfaces, in the form of multicellular aggregates commonly called biofilms. Given their ubiquity and importance in the microbial world, it is hardly surprising that biofilms have attracted the attention of the scientific community. Biofilm formation on medical implant devices such as catheters is also a major problem that is closely tied to the adhesion and resistance-related abilities of the biofilm.Methodology: The ability of 216 bacterial isolates from mid-stream urine (100), catheter-stream urine (52) and catheter tips (64) to form biofilms was investigated using the tissue culture plate method, the tube and Congo red agar methods as well as their antibiotic resistance profiles using the agar disc diffusion method.Results: These revealed that Klebsiella spp. was the predominant bacterial genera accounting for 45.8% of the total isolates. A total of 50 isolates were biofilm-formers with 22% identified by the tissue culture plate method and 78% identified by the Congo red agar method. Klebsiella spp. had the highest ability to form biofilm while antibiotic resistance profiles showed all the biofilmformers to be multiply antibiotic resistant with least resistance to ofloxacin.Conclusion: It can therefore be concluded that some bacterial isolates associated with urinary tract infections have a propensity to form biofilm, thereby becoming multiply antibiotic resistant, and ofloxacin remains the antibiotic of choice in the treatment of such infections.


Author(s):  
Sarita Manandhar ◽  
Anjana Singh ◽  
Ajit Varma ◽  
Shanti Pandey ◽  
Neeraj Shrivastava

Abstract Background Coagulase-negative staphylococci (CNS) survive as commensals of skin, anterior nares and external canals of human and were regarded as non-infectious pathogens. However, they are emerging as a major cause of nosocomial infectious due to their ability to form biofilms and high resistance to several classes of antibiotics. This study examines the biofilm forming abilities of 214 clinical CNS isolates using phenotypic and genotypic methods, and determines their antibiotic susceptibility patterns. Methods A total of 214 clinical isolates collected from different clinical samples were identified as CNS and their antibiotic susceptibility determined by CLSI guidelines. The biofilm forming ability of all isolates was determined by three phenotypic methods; Congo red agar (CRA) method, tube adherence method (TM) and tissue culture plate (TCP) method and by genotypic method for the detection of icaAD genes. Results Among all the isolates, S. epidermidis (57.5%) was found the most frequently, followed by S. saprophyticus (18.7%), S. haemolyticus (11.2%), S. hominis (7%), and S. capitis (5.6%). Antibiotic susceptibility pattern demonstrated 91.6% isolates were resistant to penicillin and 66.8% to cefoxitin while 91.1% isolates were susceptible to chloramphenicol. Constitutive and inducible clindamycin resistant phenotype as measured by D-test was seen among 28% and 14.5% of isolates respectively. Tissue culture plate method detected biofilm production in 42.1% isolate followed by 31.8% through tube method while 20.1% isolates were found to produce slime in Congo red agar method. The genotypic assay revealed presence of icaA and icaD genes in 19.2% isolates. Conclusion The study shows a high prevalence of biofilm formation and inducible clindamycin resistance in CNS isolates, indicating the importance of in-vitro biofilm production test and D-test in routine laboratory diagnostics. Implementation of efficient diagnostic techniques for detection of biofilm production in clinical samples can help manage staphylococcal infections and minimize risks of treatment failures in hospitals.


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