Biofilm and metallo beta-lactamase production among the strains of Pseudomonas aeruginosa and Acinetobacter spp. at a Tertiary Care Hospital in Kathmandu, Nepal

Abstract

Introduction Pseudomonas aeruginosa and Acinetobacter spp. are found to be associated with biofilm and metallo-β-lactamase production and are the common causes of serious infections mainly in hospitalized patients. So, the main aims of this study were to determine the rates of biofilm production and metallo beta-lactamase production (MBL) among the strains of Pseudomonas aeruginosa and Acinetobacter spp. isolated from hospitalized patients.MethodsA total of 85 P. aeruginosa isolates and 50 Acinetobacter spp. isolates isolated from different clinical specimens from patients admitted to Shree Birendra Hospital, Kathmandu, Nepal from July 2013 to May 2014 were included in this study. The bacterial isolates were identified with the help of biochemical tests. Modified Kirby-Bauer disc diffusion technique was used for antimicrobial susceptibility testing. Combined disc diffusion technique was used for the detection of MBL production, while Congo red agar method and tube adherence method were used for detection of biofilm production.ResultsAround 16.4% of P. aeruginosa isolates and 22% of the strains of Acinetobacter spp. were metallo β-lactamase producers. Out of 85 P. aeruginosa isolates, 23 (27.05%) were biofilm producers according to tube adherence test while, only 13 (15.29%) were biofilm producers as per Congo red agar method. Similarly, out of 50 Acinetobacter spp. 7 (14%) isolates were biofilm producers on the basis of tube adherence test, while only 5 (10%) were positive for biofilm production by Congo red agar method. Highest rates of susceptibility of P. aeruginosa as well as Acinetobacter spp. were seen toward colistin.ConclusionIn our study, biofilm production and metallo beta-lactamase production were observed among Pseudomonas aeruginosa and Acinetobacter spp. However, no statistically significant association could be established between biofilm production and metallo beta-lactamase production.

Study of genetic diversity, biofilm formation, and detection of Carbapenemase, MBL, ESBL, and tetracycline resistance genes in multidrug-resistant Acinetobacter baumannii isolated from burn wound infections in Iran

“…Similar to other studies, our findings showed very high rates of biofilm formation in XDR A. baumannii strains [24], and this phenomenon is associated with protective properties of persistent cells in the biofilms,and could be a result of inadequate penetration of antimicrobial agents into the biofilms [24, 25]. Our study results showed a statistically significant association between antimicrobial resistance phenotypes and biofilm formation, which was in line with other findings [9, 24], but it was in contrast to results of the study by Baniya et al [25]. A. baumannii strains formed strong biofilm were endemic in respective hospitals, indicating that microbial cells grown in biofilms are more resistant to different environmental stress conditions [24].…”

“…This resistance could result from modification of Lipopolysaccharide (LPS) at outer cell envelope, but identification of mechanism of colistin resistance in these isolates was beyond scope of our study [23]. Similar to other studies, our findings showed very high rates of biofilm formation in XDR A. baumannii strains [24], and this phenomenon is associated with protective properties of persistent cells in the biofilms,and could be a result of inadequate penetration of antimicrobial agents into the biofilms [24, 25]. Our study results showed a statistically significant association between antimicrobial resistance phenotypes and biofilm formation, which was in line with other findings [9, 24], but it was in contrast to results of the study by Baniya et al [25].…”

Study of biofilm formation and antibiotic resistance pattern of gram-negative Bacilli among the clinical isolates at BPKIHS, Dharan

“…(26.31%) and Acinetobacter spp. (20.63%) as the major MBL producers which are in conformity with the data of Kaur et al (34.8%), Anuradha et al (28.57%) and Baniya et al (22%) for the respective organisms [18, 20, 31]. The coexistence of biofilm along with both beta-lactamases producing strains was found to be 2.87%.…”

Association of biofilm production in ESBL and MBL producing clinical isolates of Pseudomonas aeruginosa

“…In the present study, among a total of 82 isolates of P. aeruginosa, 22(26.3%) were biofilm-producer and this finding is comparable with other studies which show (27.05%) [20], (32.3%) [21] and (33%) [22], but in contrast with others who showed higher rate of biofilm production (73.68%) [12] and (83.33%) [23]. This variation in the rate of isolation also may be due to sample size, type of specimen studied because medical devices were frequently colonized by biofilm-forming organisms and the various methods used for biofilm identification like Congo red agar method or Tissue culture plate which were showing a higher rate of detection.…”

“…It was similar to another study [26] but the contrast study done by Dumaru et al [12]. No statistically significant association could be established between MBL production and biofilm production (Statistically insignificant, p=0.19) which was in agreement with another study [20]. The resistance to antimicrobials in biofilm-producer may be explained by the fact like, there are an increased plasmid transfer and gene transfer among biofilm bacteria which further intensifies the problem of drug resistance [27] and also by the fact that in the process of biofilm development, drug resistance varies bacterium to bacterium [28].…”