scholarly journals Biofilm Formation and blaOXA Genes Detection Among Acinetobacter baumannii from Clinical Isolates in a Tertiary Care Kirtipur Hospital, Nepal

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.  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helal F. Hetta ◽  
Israa M. S. Al-Kadmy ◽  
Saba Saadoon Khazaal ◽  
Suhad Abbas ◽  
Ahmed Suhail ◽  
...  

AbstractWe aimed to isolate Acinetobacter baumannii (A. baumannii) from wound infections, determine their resistance and virulence profile, and assess the impact of Silver nanoparticles (AgNPs) on the bacterial growth, virulence and biofilm-related gene expression. AgNPs were synthesized and characterized using TEM, XRD and FTIR spectroscopy. A. baumannii (n = 200) were isolated and identified. Resistance pattern was determined and virulence genes (afa/draBC, cnf1, cnf2, csgA, cvaC, fimH, fyuA, ibeA, iutA, kpsMT II, PAI, papC, PapG II, III, sfa/focDE and traT) were screened using PCR. Biofilm formation was evaluated using Microtiter plate method. Then, the antimicrobial activity of AgNPs was evaluated by the well-diffusion method, growth kinetics and MIC determination. Inhibition of biofilm formation and the ability to disperse biofilms in exposure to AgNPs were evaluated. The effect of AgNPs on the expression of virulence and biofilm-related genes (bap, OmpA, abaI, csuA/B, A1S_2091, A1S_1510, A1S_0690, A1S_0114) were estimated using QRT-PCR. In vitro infection model for analyzing the antibacterial activity of AgNPs was done using a co-culture infection model of A. baumannii with human fibroblast skin cell line HFF-1 or Vero cell lines. A. baumannii had high level of resistance to antibiotics. Most of the isolates harbored the fimH, afa/draBC, cnf1, csgA and cnf2, and the majority of A. baumannii produced strong biofilms. AgNPs inhibited the growth of A. baumannii efficiently with MIC ranging from 4 to 25 µg/ml. A. baumannii showed a reduced growth rate in the presence of AgNPs. The inhibitory activity and the anti-biofilm activity of AgNPs were more pronounced against the weak biofilm producers. Moreover, AgNPs decreased the expression of kpsMII , afa/draBC,bap, OmpA, and csuA/B genes. The in vitro infection model revealed a significant antibacterial activity of AgNPs against extracellular and intracellular A. baumannii. AgNPs highly interrupted bacterial multiplication and biofilm formation. AgNPs downregulated the transcription level of important virulence and biofilm-related genes. Our findings provide an additional step towards understanding the mechanisms by which sliver nanoparticles interfere with the microbial spread and persistence.


2021 ◽  
Vol 71 (11) ◽  
pp. 2576-2581
Author(s):  
Saima Ishtiaq ◽  
Sidrah Saleem ◽  
Abdul Waheed ◽  
Arslan Ahmed Alvi

Objective: To evaluate carbapenem resistance and to detect blaOXA-23 and blaOXA-51 genes in carbapenem-resistant acinetobacter baumanii isolates recovered from patients having pneumonia secondry to ventilation. Methods: The cross-sectional study was conducted from July 2017 to June 2018 at the Department of Microbiology, University of Health Sciences, Lahore, Pakistan, and comprised endotracheal aspirates / tracheobroncheal lavage samples from patients irrespective of age and gender who developed pneumonia after being on the ventilator for 48 hrs at the Combined Military Hospital, and Jinnah Hospital, Lahore.  The samples were inoculated on MacConkey and blood agar and aerobically incubated at a temperature of 370C for 18-24 hours. The isolated organisms were further assessed by standard morphological, cultural and biochemical profile. Antibiotic susceptibility was done by Kirby-Bauer disc diffusion method. Carbapenem-resistant acinetobacter baumannii were checked for carbapenemase production using Modified Hodge Test. Conventional polymerase chain reaction and agarose gel electrophoreses were performed to detect blaOXA-23 and blaOXA-51 genes. Data was analysed using SPSS 17. Results: Out of 157 samples, 92(58.6%) yielded growth of bacteria, and, among them, 39(42.4%) were identified as acinetobacter baumannii. All (100%) acinetobacter baumannii cases showed resistance to carbapenem, were producing carbapenemase enzyme, and were positive for blaOXA-51 gene. The blaOXA-23 gene was amplified in 38(97.4%) isolates. Conclusion: BlaOXA-23 gene appeared to be the major cause of carbapenem resistance. Continuous...


Author(s):  
Fateme DAVARZANI ◽  
Navid SAIDI ◽  
Saeed BESHARATI ◽  
Horieh SADERI ◽  
Iraj RASOOLI ◽  
...  

Background: Pseudomonas aeruginosa is one of the most common opportunistic bacteria causing nosocomial infections, which has significant resistance to antimicrobial agents. This bacterium is a biofilm and alginate producer. Biofilm increases the bacterial resistance to antibiotics and the immune system. Therefore, the present study was conducted to investigate the biofilm formation, alginate production and antimicrobial resistance patterns in the clinical isolates of P. aeruginosa. Methods: One hundred isolates of P. aeruginosa were collected during the study period (from Dec 2017 to Jul 2018) from different clinical samples of the patients admitted to Milad and Pars Hospitals at Tehran, Iran. Isolates were identified and confirmed by phenotypic and genotypic methods. Antimicrobial susceptibility was specified by the disk diffusion method. Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively. Results: Sixteen isolates were resistant to all the 12 studied antibiotics. Moreover, 31 isolates were MultidrugResistant (MDR). The highest resistance rate was related to ofloxacin (36 isolates) and the least resistance was related to piperacillin-tazobactam (21 isolates). All the isolates could produce the biofilm and alginate. The number of isolates producing strong, medium and weak biofilms was equal to 34, 52, and 14, respectively. Alginate production was more than 400 μg/ml in 39 isolates, 250-400 μg/ml in 51 isolates and less than 250 μg/ml in 10 isolates. Conclusion: High prevalence of MDR, biofilm formation, and alginate production were observed among the clinical isolates of P. aeruginosa. The results also showed a significant relationship between the amount of alginate production and the level of biofilm formation.


Author(s):  
Ranjit Sah ◽  
Shusila Khadka ◽  
Gentle Sunder Shrestha ◽  
Subhash Acharya ◽  
Diptesh Aryal ◽  
...  

Abstracts Background Resistance to antimicrobial agents of pathogenic bacteria has become a major problem in routine medical practices. Carbapenem resistance has long been increasing. The production of carbapenem- hydrolysing β-lactamases (carbapenamases), which include NDM, KPC, OXA-48, IMP-1 and VIM is the most common mechanism. Case presentation A 56 years old male presented with fever and mental changes with progressively decreasing sensorium for the last 3 days. He was admitted to Intensive care unit (ICU) with a diagnosis of meningoencephalitis. On day seven, he developed ventilator associated pneumonia due Klebsiella pnemoniae and Acinetobacter baumannii. He was on meropenem, but the isolates were susceptible to colistin, tigecyclin and amikacin solely. Hence, amikacin was started with addition of intravenous and nebulized colistin. Subsequently, vital signs improved with resolution of fever. However, on day 18, he developed fever once again with a drop in blood pressure. Inotropic support was maintained, and echinocandins and tigecycline were added to the regimen. Repeat blood and urine culture grew Providencia species, which were resistant to most of the drugs on phenotypic Kirby-Bauer disk diffusion method and are intrinsically resistant to colistin and tigecycline. Phenotypic detection of ESBL (combined disk method), MBL, KPCs, AmpC and co-producer were tested according to updated CLSI guideline and all were negative. But the Modified Hodges test was found to be positive. Consequenty, OXA-48 drug resistance pattern was brought into action by blank disc method according to A Tsakris et al., which revealed indentation of growth toward both EDTA and EDTA/PBA disk indicating production of OXA-48 carbapenamase. To confirm the resistance pattern we processed the isolated colonies for Xpert Carba-R (Cepheid) assay, which detected blaOXA-48 gene and confirmed the OXA-48 drug resistance pattern. Hence, the infecting organism was not susceptible to any of the antibiotics. The patient was kept under isolation and on 31th day of admission, he died of septic shock. Conclusions Carbapenamase production along with intrinsic colistin resistance in infecting bacterial pathogens can cause fatal outcomes in the resource limited countries like Nepal where new antibiotic combinations ceftazidime+ Avibactam, or aztreonam +avibactam are not available. Drug resistance patterns including OXA 48 producer should be characterized in all cases by standard phenotypic methods or by Xpert Carba-R assay and larger studies are required to know the exact burden of OXA 48 producer in Nepal.


2020 ◽  
pp. 517-527
Author(s):  
Sarab Murad Kadum

A total of 157 clinical samples were collected from different clinical specimens (urine, sputum, blood, swabs, and cannula) from several hospitals in Iraq. Among the samples, 51 isolates (32.48%) of Klebsiella pneumoniae were identified according to morphologicaland cultural characteristics as well as the Enterosystem 18R test. Higher numbers of K. pneumoniae isolates were observed in urine samples (26, 52%) than the other samples, and in females (70.6%) than males (29.4%) (female: male ratio of about 2.4:1). Antibiotic susceptibility of K. pneumoniae against 12 commonly used antibiotics was determined through the disc-diffusion method. The results revealed a higher resistance rate in 51 isolates (100%) against Cephalexin, followed by Ceftazidime (50, 98%), while the lowest resistance rate (24, 47%) was against each of Imipenem and Meropenem. Also, the investigation of the minimum inhibitory concentration (MIC) of Colistin using E-test (strips) demonstrated that 33 isolates were resistance, as compared to 31 using the disk diffusion assay. DNA was extracted from K. pneumoniae isolates and molecularly tested using polymerase chain technique (PCR) with a specific primer and 108 bp product to detect the rpoB gene that represents this bacteria . Also, all of the 51 isolates of K. pneumoniae identified by the rpoB gene were detected for the expression of the Colistin drug resistance gene mgr-B , which was amplified (347 bp) using a specific primer. Colistin resistance gene mgr-B was amplified and sequenced from the twenty isolates. Only 6 isolates appeared with a single nucleotide substitution; G instead A, A instead G, C instead G and G instead C. Also, this study tested biofilm formation from K. pneumoniae isolates , using the microtiter plate method, in association with Colistin and Carbapenem resistant. The Colistin and Carbapenem resistance pattern was compared to the ability of biofilm-formation as weak formation versus strong and also, Multi-drug resistant isolates were more common among weak versus strong biofilm formers.


2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Kiana Karimi ◽  
Omid Zarei ◽  
Parinaz Sedighi ◽  
Mohammad Taheri ◽  
Amin Doosti-Irani ◽  
...  

Aim. Klebsiella pneumoniae (K. pneumoniae) is an encapsulated Gram-negative bacterium that can lead to 14–20% of nosocomial infections. The ability of biofilm formation in this bacterium decreases the host immune response and antibiotic efficacy. This may impose a huge impact on patients and healthcare settings. This study aimed to evaluate the antibiotic resistance pattern and biofilm formation in K. pneumoniae strains isolated from two major Hamadan hospitals, west of Iran. Methods. A total of 83 K. pneumoniae strains were isolated from clinical samples of patients in different wards of Hamadan hospitals from September 2018 to March 2019. Determination of antimicrobial susceptibility was performed using the disk diffusion method. Biofilm formation was evaluated by the crystal violet method. Data were analyzed by the SPSS software and chi-square test. Results. The results showed that clinical samples included 18 urinary tract samples (22%), 6 wound samples (7%), 6 blood samples (7%), 17 tracheal tube aspiration samples (20%), 32 throat cultures (38%), 2 sputum samples (2.5%), and 2 abscess drain cultures (2.5%). High-level resistance to cefotaxime was detected in 92%, and all of isolates were susceptible to colistin. Biofilm formation was seen in 62 (75%) isolates. Strong biofilm formation was observed in 17 (20%) strains. A significant correlation was seen between biofilm formation and antibiotic resistance ( P value <0.05). Conclusion. Our findings emphasize the need for proper diagnosis, control, and treatment of infections caused by K. pneumoniae especially in respiratory tract infections due to the strong biofilm formation and high antibiotic resistance in these strains.


2020 ◽  
Vol 20 (4) ◽  
pp. 543-549
Author(s):  
Zeinab Babaie ◽  
Somayeh Delfani ◽  
Faranak Rezaei ◽  
Fatemeh Norolahi ◽  
Somayeh Mahdian ◽  
...  

Background: Acinetobacter baumannii is an opportunistic pathogen, which causes a wide range of infections in hospitals, especially in intensive care units. Nowadays, due to the high resistance of Acinetobacter bumanni to antibiotics, this study, in addition to the phenotypic and genotypic investigations of drug resistance, focused on determining the molecular types of Acinetobacter baumannii isolated from patients in Khorramabad city by the pulsed-field gel electrophoresis (PFGE) method. Materials and Methods: In this cross-sectional study, 50 samples of Acinetobacter baumannii were collected from educational hospitals in Khorramabad city, Iran, from January to August 2015. They were identified in the laboratory using biochemical tests and culture methods. After determining the drug resistance pattern by the disc diffusion method and percentage of resistance genes to carbapenems, Acinetobacter baumannii isolates were analyzed using the PFGE method using the Apa1 enzyme. Results: The highest antibiotic resistance observed for Acinetobacter baumannii strains was against ampicillin-sulbactam (100%) and aztreonam (98%). The highest sensitivity was to polymixin B (100%) and colistin (94%), and also to the OXA-51-like gene present in all samples. The OXA-23-like gene was positive in 44 (88%) samples. PFGE results showed that Acinetobacterbaumannii strains had 33 different pulsotype patterns, of which 27 patterns had more than one strain and 23 had only one strain. Conclusion: Due to the high resistance of Acinetobacter baumannii and its ease of spread and its ability to transfer resistance genes, resistance control methods should be used in the disinfection of hospital areas. Hospital staff should observe hygiene standards and there should also be a reduction in antibiotic use.


2007 ◽  
Vol 28 (8) ◽  
pp. 941-944 ◽  
Author(s):  
Thean Yen Tan ◽  
Karen Poh ◽  
Siew Yong Ng

Objective.To investigate the molecular epidemiology of carbapenem-resistantAcinetobacter baumannii-calcoaceticuscomplex isolates in a tertiary care hospital where the prevalence of carbapenem resistance among these organisms is high.Design.The study was a prospective, observational study performed during an 8-month period (May 1 through December 31, 2004).A. baumanniiisolates recovered from all clinical samples during the study period were included in the study. Antibiotic susceptibility testing was performed using the disk diffusion method, and all carbapenem-resistant strains were typed by a polymerase chain reaction-based typing method.Setting.An 800-bed hospital in Singapore.Results.More than half of recovered isolates were clonally unrelated, with the remaining isolates grouped into 4 genotypes.Conclusions.The results of the study suggest that the high prevalence of carbapenem resistance amongAcinetobacterorganisms in this institution is not caused by the spread of a predominant clone and that other factors may need to be investigated.


Author(s):  
Mousumi Karmaker ◽  
Md. Abul Khair ◽  
Una Jessica Sarker ◽  
Rabeya Nahar Ferdous ◽  
Sa’dia Tasnim ◽  
...  

Pseudomonas aeruginosa is one of the most widespread gram-negative microorganisms identified in the clinical samples and most common causes of hospital acquired infection. P. aeruginosa is affecting both indoor and outdoor patients throughout the world. Due to frequent mutation in          P. aeruginosa highly resistant strain developed rapidly. The aim of the study to determine the prevalence of P. aeruginosa species in different samples isolated from a Tertiary care Hospital as well as determination their diverse antibiotic resistance pattern. This cross-sectional study was carried out to determine in-vitro resistance pattern of P. aeruginosa isolates to common antimicrobial agents by disc diffusion method. Various clinical samples were collected from Bangladesh Health Sciences Hospital (BIHS) General Hospital, Dhaka. This research was carried out in the Department of Microbiology of Bangladesh University of Health Sciences (BUHS). Isolation, identification and antibiogram were performed for P. aeruginosa following standard microbiological laboratory procedure. A total of 218 P. aeruginosa were isolated from 3062 different clinical specimens which are statistically significant (p<0.0001). Among the highest number of P. aeruginosa were isolated from outdoor patients 140 compare to Indoor patients which are significantly higher (p <0.013). In this study Male (68.3%) are more vulnerable to P. aeruginosa infection compare to females (31.7%) which is also statistically significant. Young people (less than 35 years) were more susceptible to P. aeruginosa infection which is also statistically significant (p< 0.01). The highest number of P. aeruginosa was isolated from wound (43.12%), followed by pus (40.33%), sputum (8.71%) urine (7.80%). The maximum number of P. aeruginosa in various samples was resistant to aztreonam and co-tromoxazole followed by cephalosporins, aminoglycosides, carbapenems. The most sensitive antibiotic was colistin of followed by gentamycin and tetracycline. To control the spread of resistant bacteria, it is disparagingly vital to have stringent antibiotic guidelines. The antibiotic susceptibility pattern of P. aeruginosa requires to be continuously monitored in specialized clinical units and the results readily made available to the clinicians to minimize the resistance.


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