Table 2.
Association between biofilm formation and antimicrobial resistance in Acinetobacter spp.
| Sr. no | Study | Country | Strain (numbers) | Sources of isolation | % of biofilm formers | Observations | References |
|---|---|---|---|---|---|---|---|
| Positive correlation between biofilm formation and antibiotic resistance | |||||||
| 1. | Rao et al., 2008 | India | A. baumannii (50) | Endotracheal aspirates, cerebrospinal fluid, wound swabs, urine, blood | 62%-high biofilm former | • Resistance to four antibiotics such as amikacin (82 vs. 17.6%, P < 0.001), cephotaxime (88 vs. 11%, P < 0.001), ciprofloxacin (70 vs. 29%, P = 0.005), and aztreonam (38 vs. 11%, P = 0.039) was comparatively higher among biofilm producers than non-biofilm producers. • blaPER−1-horbouring A. baumannii was able to form strong biofilm in comparison to the isolates that did not possess the gene. |
(92) |
| 2. | Lee et al., 2008 | Korea | A. baumannii (23) | Blood, sputum, urine | 100%- biofilms former | • Cell adhesiveness and biofilm formation were significantly higher in isolates carrying the blaPER−1 as compared with isolates without this gene (P < 0.005 and P < 0.001, respectively). • RT-PCR showed a positive correlation between the level of expression of the blaPER−1 and the level of biofilm formation (P < 0.0001). |
(83) |
| 3. | Pour et al., 2011 | India | • A. baumannii (47); • A. lowffii (3) |
Urine samples, urinary catheters | • 12%- strong biofilm former • 10%-low biofilms former |
• High biofilm forming strains exhibited high resistance to 27 antibiotics from different groups including β-lactam group (83.3%), cephalosporin group (94.4%), aminoglycosides (97%), quinolones (75%), tetracycline (66.6%) and oxytetracycline, and imipenem (33.3%). | (115) |
| 4. | Nahar et al., 2013 | Bangladesh | • A. baumannii (32) from ICU patients • A. baumannii (20) from non-ICU patients |
Tracheal aspirates, blood, central venous catheter, peripheral blood, urine, wound swab, pus, throat swab, endotracheal tubes, burn samples, ascitic fluid, sputum, aural swab, oral swab, cerebrospinal fluid, and catheter tip | • 87.5%- biofilm former from ICU patients • 55%- biofilm former from non-ICU patients |
• Resistance to antibiotics such as gentamicin (100 vs. 88.9%), amikacin (85.7 vs. 55.6%), netilmicin (85.7 vs. 11.1%), ciprofloxacin (82.1 vs. 54.4%), imipenem (81.0 vs. 22.2%) and colistin (7.1 vs. 0%) was higher among biofilm forming Acinetobacter spp. isolated from ICU than non-ICU isolates. | (144) |
| 5. | Emami and Eftekhar, 2015 | Iran | • A. baumannii (30) from burn unit • A. baumannii (30) from non-burn unit |
• The burn isolates were mostly from wounds, blood, urine. • Non-burn isolates were from sputum, wound specimens, catheters, blood, cerebral spinal fluid, trachea |
• 55.5%- biofilm former in non-burn isolates • 40.5%- biofilm former in burn isolates |
• Non-burn strains significantly produced more biofilm compared to the burn strains (P < 0.05). • Biofilm-producing non-burn isolates were significantly more resistant to amikacin, meropenem, and tobramycin compared to the biofilm negative strains within the same group (P < 0.05). • AmpC and ESBL was much higher among the non-burn isolates compared to the burn samples (33.0 vs. 3.3%, P < 0.05). |
(145) |
| 6. | Thummeepak et al., 2016 | Thiland | A. baumannii (221) | Sputum, urine, pus, blood, pleural fluid, ascetic fluid, and wound | 76.9%- biofilm former | • The association between biofilm forming ability and gentamicin resistance was found to be significant (P = 0.017). • Antibiotic-resistant isolates possessed ompA (84.4%), bfmS (84%), bap (48%), blaPER−1 (30.2%) and epsA genes (30.2%). However, biofilm formation related genes ompA and bap were associated with multidrug-resistant A. baumannii strains. |
(139) |
| 7. | Bardbari et al., 2017 | Iran | • A. baumannii (75) from clinical samples • A. baumannii (32) from environmental samples |
• Sputum, bronchoalveolar lavage, endotracheal aspiratesventilators, sink • Area, floor, hand staff, trolleys and bedside table, pillow and linens, and other fomites |
• 31.2%- strong biofilm forming clinical isolates • 58.7%- strong biofilm forming environmental isolates |
• Clinical strains showed strong biofilm production ability compared to environmental strains (58.7 vs. 31.2%). • Significant correlation was observed between the frequency of multidrug-resistant isolates and biofilm formation ability in both clinical and environmental strains (P = 0.008). • The study revealed the presence of blaOXA−51, blaOXA−23, blaOXA−24, blaOXA−58, and blaPER−1 among biofilm forming A. baumannii. |
(94) |
| 8. | Khamari et al., 2019 | India | A. baumannii (14) | Blood, pus, urine, pleural fluid, endotracheal tube | • 100%- biofilm former • 71.4%-strong biofilm former |
• blaTEM, blaOXA, blaNDM, blaVIM, blaSIM, and blaPER−1; class 1 integron were detected among the isolates. | (93) |
| 9. | Yang et al., 2019 | Taiwan | A. baumannii (152) | No data available | • 45.4%- strong biofilm former • 32.5%- moderate biofilm former • 15.6%- weak biofilm former |
• A positive correlation was observed between biofilm forming capacity and resistance to ticarcillin, amikacin, gentamicin, ceftazidime, piperacillin, imipenem, and sulfamethoxazole-trimethoprim antibiotics (P = 0.018, 0.004, 0.003, 0.003, 0.033, 0.017, 0.007, respectively). • The study also revealed that biofilms-related genes such as bap, blaPER, ompA, and csuE genes were found in 81, 39, 91, and 69% of the biofilm producers, respectively. The strains carrying these genes formed stronger biofilm than the isolates without these genes. |
(140) |
| 10. | Ranjbar et al., 2019 | Iran | A. baumannii (161) | Burn wood infections | • 70.6%- strong biofilm former • 12.2%- moderate biofilm former • 17.2%- weak biofilm former |
• A significant association was observed between biofilm-forming ability and XDR phenotype (P = 0.001). • Multiple genes (blaOXA−23−like/blaOXA−40−like/blaOXA−51, blaPER−1/blaVEB−1, blaIMP, and blaVIM and tetB) were found to be responsible for detection of drug-resistance in burn patients. |
(141) |
| 11. | Celik et al., 2020 | Turkey | A. baumannii (60) | Tracheal aspirates, blood, urine, wound, sputum, CSF, abscess, bronchoalveolarlavagefluid | 90%- biofilm former | • In biofilm-positive strains, antibiotic resistance was significantly higher against ampicillin/sulbactam, cefoperazone-sulbactam, chloramphenicol, piperacillin/tazobactam, and ciprofloxacin (P = 0.008, 0.038, 0.017, 0.027, 0.005, respectively). | (142) |
| 12. | Asaad et al., 2021 | Egypt | A. baumannii (161) | Sputum, endotracheal aspirate, wound swab | • 20.2%- strong biofilm former • 34%- moderate biofilm former • 16%- weak biofilm former |
• Biofilm-producing isolates showed statistically significant higher resistance rate to ceftazidime, ampicillin/sulbactam, piperacillin/tazobactam, piperacillin, gentamycin, trimethoprim/sulfamethoxazole, tigecycline, and imipenem (P = 0.041, < 0.001, 0.006, 0.034, 0.028, 0.002, 0.002, and 0.02, respectively). • Presence of ompA gene (P = 0.002), bap gene (P = 0.012), MDR (P = 0.017), and XDR (P = 0.002) was significantly associated with biofilm-producing capability of the isolates, compared to non-biofilm producing capabilities. |
(143) |
| Negative correlation between biofilm formation and antibiotic resistance | |||||||
| 1. | Rodríguez-Ba no et al., 2008 | Spain | A. baumannii (92) | No data available | 63%- biofilm former | • In comparison to non-biofilm forming A. baumannii, biofilm forming isolates were less frequently resistant to ciprofloxacin and imipenem (47 vs. 25%, P = 0.04; and 94 vs. 66%, P = 0.004, respectively). | (146) |
| 2. | Han et al., 2014 | China | A. baumannii (70) | No data available | • 50%- strong biofilm former • 29%- moderate biofilm former • 21%- weak biofilm former |
• Resistance to levofloxacin (85.71%, 45.00%, 38.24%, P = 0.010), cefepime (71.43%, 45.00%, 29.41%, P = 0.027), and gentamicin (78.57%, 55.00%, 38.24%, P = 0.037) significantly decreased when biofilm-forming ability was strong. | (147) |
| 3. | Zhang et al., 2016 | China | A. baumannii (120) | Sputum | • 27.3%- strong biofilm former • 54.5%- moderate biofilm former • 18.2%- weak biofilm former |
• Isolates which produced strong biofilm exhibited low-level resistance to gentamicin, minocycline, and ceftazidime (P < 0.05). | (148) |
| 4. | Qi et al., 2016 | China | A. baumannii (268) | No data available | • 23%- strong biofilm former • 74.7%- weak biofilm former |
• Among the strong biofilm-formers, 79.4% were non-MDR isolates and, 20.6% were MDR/XDR ones. • Among the weak biofilm-formers, 12.4% non-MDR and 87.6% MDR/XDR isolates. • Strains that were negative for biofilm formation consisted of 8.7% non-MDR and 91.3% MDR/XDR isolates. |
(31) |
| 5. | Krzysciak et al., 2017 | Poland | A. baumannii (15) | Blood, central nervous system, pulmonary | 80–90%- biofilm former | • Strains showing sensitivity to amikacin, tobramycin, trimethoprim/sulfamethoxazole and ciprofloxacin from ICU patients produced more biofilm than strains showing resistance to these antibiotics. | (149) |
| 6. | Wang et al., 2018 | Taiwan | A. baumannii (269) | Blood | 26%- biofilm former | • MDR isolates was significantly lower (P = 0.006) in the biofilm-forming group. • Biofilm-forming isolates were significantly more susceptible to most commonly used antibiotics including amikacin, gentamicin, ceftazidime, cefepime, ciprofloxacin, imipenem, and meropenem (P = 0.040,0.043, 0.003, 0.009, 0.001, 0.035, 0.018, respectively). |
(150) |
| 7. | Shenkutie et al., 2020 | China | A. baumannii (104) | Sputum, blood, urine, soft tissue, hospital environments | • 25%- strong biofilm former • 14.4%- moderate biofilm former • 20.2%- weak biofilm former |
• Non-MDR strains (66.1%) showed strong biofilm formation. | (151) |
Studies have been arranged in chronological order.