Strong Biofilm Producers Research Articles

Isolation and identification of multi-drug resistance Acinetobacter baumannii isolated from clinical samples at Baghdad, Iraq

An opportunistic bacterium called Acinetobacter baumannii has significantly increased the frequency of infections in recent years. With only a limited number of “traditional” virulence factors, It is infections have spread rapidly through hospitals across the globe. The present study aimed to work out the relationship between the multi-drug resistance (MDR) of A. Baumannii and biofilm formation. A total of 150 samples were collected from various clinical sources from different age groups and gender patients in Ghazi AL Hariri Hospital and Baghdad Teaching laboratories in Medical City in Baghdad, Iraq from December 2021 to March 2022. Microscopical inspection and cultural features on various culture media, including culturing on selective medium CHROMagar, were used to identify bacterial isolates. The characteristics of the isolates were then established by some biochemical tests. Identification was confirmed using the Vitek-2 system with an accuracy of 99%, which revealed that only (50) isolates were given identical morphological characteristics and biochemical tests belonging to Acinetobacter baumannii isolates. 28 (56%) isolates were collected from burns. 10 isolates (20%) and 9 isolates (18% were collected from wound and sputum cultures of A. baumannii , respectively, while only 3 isolates (6%) were from urine culture. The susceptibility test for all the fifty clinical isolates of A. baumannii was performed against 10 different antibiotics. The results showed that A. baumannii isolates were Multidrug-resistant (MDR) (98%), while the other (2%) of the isolates were extensively drug-resistance (XDR) to themajority of antibiotics tested. All 50 isolates in the present study were subjected to the micro-titer plate (MTP) assay method (96 walls). The results indicated that strong biofilm was detected in 40 (80.0%) of the tested isolates. Thirty bacterial isolates were were found to be MDR and had strong biofilm production.

Comparison of the Efficiency of Selected Disinfectants against Planktonic and Biofilm Populations of Escherichia coli and Staphylococcus aureus.

The aim of this study is to compare the efficacy of selected food disinfectants on planktonic populations of Staphylococcus aureus and Escherichia coli and on the same microorganisms (MOs) incorporated in a biofilm. Two disinfectants were used for treatment: peracetic acid-based disinfectant (P) and benzalkonium chloride-based disinfectant (D). Testing of their efficacy on the selected MO populations was performed using a quantitative suspension test. The standard colony counting procedure was used to determine their efficacy on bacterial suspensions in tryptone soy agar (TSA). The germicidal effect (GE) of the disinfectants was determined based on the decimal reduction ratio. For both MOs, 100% GE was achieved at the lowest concentration (0.1%) and after the shortest exposure time (5 min). Biofilm production was confirmed with a crystal violet test on microtitre plates. Both E. coli and S. aureus showed strong biofilm production at 25 °C with E. coli showing significantly higher adherence capacity. Both disinfectants show a significantly weaker GE on 48 h biofilms compared to the GE observed after application of the same concentrations on planktonic cells of the same MOs. Complete destruction of the viable cells of the biofilms was observed after 5 min of exposure to the highest concentration tested (2%) for both disinfectants and MOs tested. The anti-quorum sensing activity (anti-QS) of disinfectants P and D was determined via a qualitative disc diffusion method applied to the biosensor bacterial strain Chromobacterium violaceum CV026. The results obtained indicate that the disinfectants studied have no anti-QS effect. The inhibition zones around the disc therefore only represent their antimicrobial effect.

Atopic dermatitis-derived Staphylococcus aureus strains: what makes them special in the interplay with the host.

Atopic dermatitis (AD) is a chronic inflammatory skin condition whose pathogenesis involves genetic predisposition, epidermal barrier dysfunction, alterations in the immune responses and microbial dysbiosis. Clinical studies have shown a link between Staphylococcus aureus and the pathogenesis of AD, although the origins and genetic diversity of S. aureus colonizing patients with AD is poorly understood. The aim of the study was to investigate if specific clones might be associated with the disease. WGS analyses were performed on 38 S. aureus strains, deriving from AD patients and healthy carriers. Genotypes (i.e. MLST, spa-, agr- and SCCmec-typing), genomic content (e.g. virulome and resistome), and the pan-genome structure of strains have been investigated. Phenotypic analyses were performed to determine the antibiotic susceptibility, the biofilm production and the invasiveness within the investigated S. aureus population. Strains isolated from AD patients revealed a high degree of genetic heterogeneity and a shared set of virulence factors and antimicrobial resistance genes, suggesting that no genotype and genomic content are uniquely associated with AD. The same strains were characterized by a lower variability in terms of gene content, indicating that the inflammatory conditions could exert a selective pressure leading to the optimization of the gene repertoire. Furthermore, genes related to specific mechanisms, like post-translational modification, protein turnover and chaperones as well as intracellular trafficking, secretion and vesicular transport, were significantly more enriched in AD strains. Phenotypic analysis revealed that all of our AD strains were strong or moderate biofilm producers, while less than half showed invasive capabilities. We conclude that in AD skin, the functional role played by S. aureus may depend on differential gene expression patterns and/or on post-translational modification mechanisms rather than being associated with peculiar genetic features.

Antimicrobial Resistance and Biofilm Formation of Staphylococcus aureus Isolates from Febrile Cases: Findings from a Rural Cohort of Odisha, India.

This study investigated the major pathogens in fever patients' blood in a rural cohort and characterized its virulence. A total of 718 blood samples received from IPD/OPD (inpatient department/outpatient department) patients with H/O (history of) fever were cultured, and 73 out of 83 culture-positive samples were identified as Staphylococcus aureus. The isolates showed higher resistance to penicillin, most being multidrug resistant. They formed biofilm in vitro, and 27.4% of the isolates were strong biofilm producers. They were sensitive towards linezolid, gentamicin, and tetracycline. The findings emphasize the necessity of preventing and managing staphylococcal infection and regular antimicrobial surveillance in rural areas.

Molecular detection of different virulence factors genes harbor pslA, pelA, exoS, toxA and algD among biofilm-forming clinical isolates of Pseudomonas aeruginosa.

Pseudomonas aeruginosa (P. aeruginosa) is considered as the foremost cause of hospital-acquired infections due to its innate and plasmid-mediated resistance to multiple antibiotics making it a multi-drug resistant (MDR) pathogen. This study aimed to determine the biofilm formation ability and the presence of different virulence factors genes (pslA, pelA, exoS, toxA and algD) among biofilm-forming strains of P. aeruginosa clinical isolates from burn units in Ismailia Hospitals, Egypt. In our cross-sectional study, one hundred and twenty-six (126) non-duplicate clinical P. aeruginosa isolates were recovered from 450 clinical specimens from burn units in Ismailia Hospitals. The antibiotic sensitivity of strong and moderate biofilm producer isolates was investigated using the disc diffusion method. The isolated bacteria were tested for their ability to form biofilm using a microtiter plate assay. The expression of (pslA, pelA, exoS, toxA and algD) genes in biofilm producers isolates was detected using PCR. The MPA detected 80% (95 /126) isolates as biofilm producers, 18% (22/126) were strong biofilm producers, 34% (43/126) were moderate biofilm producers, 28% (35/126) were weak biofilm producers and 20% (31/126) non-biofilm producers. Susceptibility pattern analysis of biofilm-forming P. aeruginosa isolates (95) detected that 60% (68/ 95) were multi-drug resistant isolates (MDR). Resistance to all used antibiotics and multidrug resistance was higher among biofilm-producing than non-biofilm-producing strains, but the difference was statistically non-significant. Investigation of virulence factors associated genes revealed that 96%, 94%, 86.4%, 80.0% and 74% of the biofilm producers isolates were harboring algD, pslA, pel A, toxA and exoS gene, respectively. The present study confirmed that antimicrobial resistance and virulence genes were more prominent in biofilm-producing P. aeruginosa than in non-biofilm-producers.

What's New in Musculoskeletal Infection.

What's New in Musculoskeletal Infection.

Assessment of toxicity, anti-quorum sensing and anti-biofilm production effects of Hypericum triquetrifolium Turra extract on multi-drug resistant Acinetobacter baumannii

Acinetobacter baumannii is a multidrug-resistant and an invasive bacterium and a significant contributor to nosocomial infections in the present healthcare system. It’s striking capability to survive in hospital settings on medical equipments is due to its capability of quorum sensing and biofilm formation. New medications and formulations to combat this pathogen is the need of this hour. Hypericum triquetrifolium Turra, a less famous medicinal plant is known for its antibacterial characteristics. However, there is hardly any research articles or findings to back this claim against the Acinetobacter sp. Total of 50 bacterial isolates were collected. 98% of them were resistant to Ciprofloxacin. 4% showed strong biofilm production, while 40% and 56% of the isolates revealed weak and moderate bioflim production. Biochemical analysis revealed that the ethanolic leaves extract of H. triquetrifolium Turra contains potent phytochemical compounds. Toxicity assessment of the plant extract revealed that the extract was slightly toxic where LD50 was 4.95 g/Kg. Minimum inhibitory concetrations and Sub-minimum inhibitory concetrations of H. triquetrifolium Turra leaf extract against two strongest biofilm producers and ATCC strain of A. baumannii (19606) were estimated. MICs values were 10–15 mg/ml and SICs 5–10 mg/ml. Investigations revealed significant reductions in biofilm formation when isolates were treated with SICs of the extract. Transcription expression of quorum sensing genes, abaI/abaR, down regulated when treated with H. triquetrifolium extract. One of the Biofilm regulating genes among Bap/OmpA, were found to be sharply down regulated especially, Bap gene; however, OmpA gene didn’t show noticable change in the expression. We concluded that H. triquetrifolium Turra may have promising activity against A. baumannii in it’s quorum sensing and biofilm formation, thus it could be employed as potential as an antibacterial medication.

Genotypic and Phenotypic Characterization of Escherichia coli Isolates Recovered from the Uterus of Mares with Fertility Problems.

Escherichia coli is the bacterial pathogen most frequently associated with mare infertility. Here, we characterized 24 E. coli strains isolated from mares which presented signs of endometritis and infertility from a genotypic and phenotypic point of view. The majority of the isolates belonged to phylogenetic group B1 (9/24, 37.5%). Regarding antibiotic resistance profiles, 10 out of 24 (41.7%) were multidrug-resistant (MDR). Moreover, 17 out of 24 (70.8%) were strong or moderate biofilm producers, and of these eight were MDR strains. Interestingly, 21 out of 24 (87.5%) E. coli strains were phenotypically resistant to ampicillin and 10 of them were also resistant to amoxicillin with clavulanic acid. Regarding the presence of selected virulence factors, 50% of the examined strains carried at least three of them, with fimH detected in all strains, and followed by kpsMTII (11/24, 45.9%). No strain was able to invade HeLa cell monolayers. No relevant differences for all the investigated characteristics were shown by strains that grew directly on plates versus strains requiring the broth-enrichment step before growing on solid media. In conclusion, this work provides new insight into E. coli strains associated with mares' infertility. These results broaden the knowledge of E. coli and, consequently, add useful information to improve prevention strategies and therapeutic treatments contributing to a significant increase in the pregnancy rate in mares.

Effects of Piper betle Extracts against Biofilm Formation by Methicillin-Resistant Staphylococcus pseudintermedius Isolated from Dogs.

Emergence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) isolated from dogs with cutaneous and wound infections has significantly impacted veterinary medicine. This study aimed to isolate S. pseudintermedius from canine pyoderma and investigate the effects of ethanolic extracts of Piper betle (PB), P. sarmentosum (PS), and P. nigrum (PN) on the bacterial growth and biofilm formation of S. pseudintermedius and MRSP. Of the isolated 152 isolates, 53 were identified as S. pseudintermedius using polymerase chain reaction, and 10 isolates (6.58%) were identified as MRSP based on the presence of mecA. Based on phenotype, 90% of MRSPs were multidrug-resistant. All MRSP had moderate (10%, 1/10) and strong (90%, 9/10) biofilm production ability. PB extracts were the most effective in inhibiting planktonic cells, and the minimum inhibitory concentration at which ≥50% of the isolates were inhibited (MIC50) was 256 µg/mL (256-1024 µg/mL) for S. pseudintermedius isolates and 512 µg/mL (256-1024 µg/mL) for MRSP isolates. The MIC90 for S. pseudintermedius and MRSP was 512 µg/mL. In XTT assay, PB at 4× MIC showed an inhibition rate of 39.66-68.90% and 45.58-59.13% for S. pseudintermedius and MRSP, respectively, in inhibiting biofilm formation. For PB at 8× MIC, the inhibition rates for S. pseudintermedius and MRSP were 50.74-81.66% and 59.57-78.33%, respectively. Further, 18 compounds were identified in PB using gas chromatography-mass spectrometry, and hydroxychavicol (36.02%) was the major constituent. These results indicated that PB could inhibit bacteria growth of and biofilm formation by S. pseudintermedius and MRSP isolated from canine pyoderma in a concentration-dependent manner. Therefore, PB is a potential candidate for the treatment of MRSP infection and biofilm formation in veterinary medicine.

Antimicrobial resistance and molecular epidemiology of carbapenem-resistant Escherichia coli from urinary tract infections in Shandong, China.

Urinary tract infection (UTI) is one of the most common extraintestinal infections, and uropathogenic Escherichia coli (UPEC) is the main cause of UTIs. However, the ability to treat UTI has been compromised by the increase in antimicrobial resistance, especially carbapenem resistance. Here, we aimed to characterize the antimicrobial resistance and molecular epidemiology of carbapenem-resistant UPEC isolated in Shandong, China. In total, 17 carbapenem-resistant UPEC (CR-UPEC) isolates were collected from July 2017 to May 2020 in the Shandong Provincial Hospital. Whole-genome sequencing and bioinformatics analyses were performed to understand the molecular epidemiology of CR-UPEC. Phylogenetic groups, drug resistance genes, biofilm formation, and virulence-related gene profiles of the isolates were analyzed. Plasmid profiling and conjugation assay were performed to evaluate the ability to transfer carbapenem resistance-related genes to other E. coli isolates. Biofilm formation was also evaluated, as it is important for the persistence of infectious diseases. We observed that 15 out of 17 CR-UPEC strains were blaNDM producers, among which 4 isolates could transfer blaNDM to recipient cells. The predominant sequence type was ST167 (6/17), followed by ST410 (3/17). The most prevalent phylogenetic group was phylogenetic group A (10/17), followed by phylogenetic group C (3/17). One isolate was resistant to polymyxin, which was caused by the carriage of a transferable plasmid harboring mcr-1. Statistical analysis did not reveal any significant difference in the carriage rate of fimbriae-coding genes between strong and weak biofilm producers. Our observations may assist in developing new therapeutic methods for drug-resistant organisms.

Chitosan improves the efficacy of gentamicin against MDR and biofilm-forming URO pathogenic E. coli

Uropathogenic E. coli is the most common cause of urinary tract infections (UTIs), accounting for 80-90% of community-acquired UTIs and 30-50% of hospital-acquired UTIs. Uropathogenic E. coli that form biofilms are linked to chronic and persistent inflammation, resulting in severe and recurring UTIs. Biofilms promote antibiotic resistance and the horizontal transfer of virulence genes, promoting the formation of multidrug-resistant organisms. This study aimed to combine low-molecular-weight chitosan with aminoglycoside gentamicin to improve its efficacy against biofilm formation and MDR E. coli. Different strains of bacteria were isolated from urine samples of different patients at the Ayub Teaching Hospital, Abbottabad, out of which 16 were identified as E. coli by API (Analytical Profile Index) 20E. The antibiotic sensitivity profile was determined using the disk diffusion method, and the results showed that a total of 10 isolates were found to be multidrug-resistant MDR (N=62.5%). Biofilm formation was tested using the TCP method, a total of 7 isolates were found to be strong biofilm producers (N=44%). Gentamicin exhibited the highest inhibitory activity against 10 isolates of E.coli, with MIC-p ranges of 4 and 2 µg/ml, respectively, while 6 isolates showed resistance to gentamicin with MIC-p ranges >512 µg/ml.

Chitosan can improve antimicrobial treatment independently of bacterial lifestyle, biofilm biomass intensity and antibiotic resistance pattern in non-aureus staphylococci (NAS) isolated from bovine clinical mastitis.

Bovine mastitis is the most frequent and costly disease that affects dairy cattle. Non-aureus staphylococci (NAS) are currently one of the main pathogens associated with difficult-to-treat intramammary infections. Biofilm is an important virulence factor that can protect bacteria against antimicrobial treatment and prevent their recognition by the host's immune system. Previously, we found that chronic mastitis isolates which were refractory to antibiotic therapy developed strong biofilm biomass. Now, we evaluated the influence of biofilm biomass intensity on the antibiotic resistance pattern in strong and weak biofilm-forming NAS isolates from clinical mastitis. We also assessed the effect of cloxacillin (Clx) and chitosan (Ch), either alone or in combination, on NAS isolates with different lifestyles and abilities to form biofilm. The antibiotic resistance pattern was not the same in strong and weak biofilm producers, and there was a significant association (p ≤ 0.01) between biofilm biomass intensity and antibiotic resistance. Bacterial viability assays showed that a similar antibiotic concentration was effective at killing both groups when they grew planktonically. In contrast, within biofilm the concentrations needed to eliminate strong producers were 16 to 128 times those needed for weak producers, and more than 1,000 times those required for planktonic cultures. Moreover, Ch alone or combined with Clx had significant antimicrobial activity, and represented an improvement over the activity of the antibiotic on its own, independently of the bacterial lifestyle, the biofilm biomass intensity or the antibiotic resistance pattern. In conclusion, the degree of protection conferred by biofilm against antibiotics appears to be associated with the intensity of its biomass, but treatment with Ch might be able to help counteract it. These findings suggest that bacterial biomass should be considered when designing new antimicrobial therapies aimed at reducing antibiotic concentrations while improving cure rates.

Synergistic effect and antibiofilm activity of the antimicrobial peptide K11 with conventional antibiotics against multidrug-resistant and extensively drug-resistant Klebsiella pneumoniae.

Infections caused by drug-resistant Klebsiella pneumoniae are now a serious problem for public health, associated with high morbidity and mortality due to limited treatment options. Therefore, new antibacterial agents or a combination of agents as the first line of treatment are urgently needed. K11 is a novel antimicrobial peptide (AMP) that has demonstrated in vitro antimicrobial activity against several types of bacteria. Additionally, K11 has previously shown no hemolytic activity. Herein, the antibacterial activity, the synergistic action of K11 in combination with different conventional antibiotics and the antibiofilm activity of K11 against multidrug-resistant (MDR) and extensively drug-resistant (XDR) K. pneumoniae were investigated. Meanwhile, the stability and ability to induce the bacterial resistance of K11 were also tested. Fifteen clinical isolates of MDR/XDR K. pneumoniae were used in this study. The minimum inhibitory concentration (MIC) of K11 against these isolates was determined by the broth microdilution method. In vitro synergy between K11 and antibiotics was evaluated using the checkerboard methodology. The antibiofilm activity of K11 against K. pneumoniae strong biofilm producers were explored by the crystal violet staining. The stability in different environments and resistance induction of K11 were evaluated by MIC determination. The MIC values of K11 against MDR/XDR K. pneumoniae isolates were 8-512 μg/mL. Intriguingly, the synergistic effects were clearly observed for K11 in combination with chloramphenicol, meropenem, rifampicin, or ceftazidime, whereas no synergy was observed when K11 was combined with colistin. Besides, K11 effectively prevented biofilm formation against K. pneumoniae strong biofilm producers in a concentration-dependent manner starting at 0.25×MIC and exerted an enhancing effect when administered in combination with meropenem, chloramphenicol, or rifampicin. Additionally, K11 demonstrated high thermal and wide pH stability along with good stability in serum and physiological salts. Significantly, K. pneumoniae showed no induction of resistance even after prolonged exposure to a sub-inhibitory concentration of K11. These findings indicate that K11 is a promising candidate with potent antibacterial and antibiofilm activities without inducing resistance and acts synergistically with conventional antibiotics against drug-resistant K. pneumoniae.

Application of a novel lytic Jerseyvirus phage LPSent1 for the biological control of the multidrug-resistant Salmonella Enteritidis in foods.

Non-typhoidal Salmonella is the tremendously predominant source of acquired foodborne infection in humans, causing salmonellosis which is a global threat to the healthcare system. This threat is even worse when it is combined with the incidence of multidrug-resistant Salmonella strains. Bacteriophage therapy has been proposed as a promising potential candidate to control a diversity of foodborne infective bacteria. The objective of this study designed to isolate and characterize lytic phages infecting zoonotic multi-drug resistant and strong biofilm producer Salmonella enterica serovar Enteritidis EG.SmE1 and then apply the isolated phage/s as a biocontrol agent against infections in ready-to-eat food articles including milk, water, apple juice, and chicken breasts. One lytic phage (LPSent1) was selected based on its robust and stable lytic activity. Phage LPSent1 belonged to the genus Jerseyvirus within the Jerseyvirinae subfamily. The lysis time of phage LPSent1 was 60 min with a latent period of 30 min and each infected cell burst about 112 plaque-forming units. Phage LPSent1 showed a narrow host range. Furthermore, the LPSent1 genome did not encode any virulence or lysogenic genes. In addition, phage LPSent1 had wide pH tolerance, prolonged thermal stability, and was stable in food articles lacking its susceptible host for 48 h. In vitro applications of phage LPSent1 inhibited free planktonic cells and biofilms of Salmonella Enteritidis EG.SmE1 with a lower occurrence to form phage-resistant bacterial mutants which suggests promising applications on food articles. Application of phage LPSent1 at multiplicities of infections of 100 or 1000 showed significant inhibition in the bacterial count of Salmonella Enteritidis EG.SmE1 by 5 log10/sample in milk, water, apple juice, and chicken breasts at either 4°C or 25°C. Accordingly, taken together these findings establish phage LPSent1 as an effective, promising candidate for the biocontrol of MDR Salmonella Enteritidis in ready-to-eat food.

Comprehensive profiling of serotypes, antimicrobial resistance and virulence of Salmonella isolates from food animals in China, 2015-2021.

Salmonella is a ubiquitous foodborne pathogen and mainly transmitted to human farm-to-fork chain through contaminated foods of animal origin. In this study, we investigated the serotypes, antimicrobial resistance and virulence of Salmonella from China. A total of 617 Salmonella isolates were collected from 4 major food animal species across 23 provi nces in China from 2015-2021. Highest Salmonella prevalence were observed in Guangdong (44.4%) and Sandong (23.7%). Chickens (43.0%) was shown to be the major source of Salmonella contamination, followed by pigs (34.5%) and ducks (18.5%). The number of Salmonella increased significantly from 5.51% to 27.23% during 2015-2020. S. Derby (17.3%), S. Enteritidis (13.1%) and S. Typhimurium (11.4%) were the most common serotypes among 41 serotypes identifiedin this study. Antibiotic susceptibility testing showing that the majority of the Salmonella isolates were resistant to neomycin (99.7%), tetracycline (98.1%), ampicillin (97.4%), sulfadiazine/trimethoprim (97.1%), nalidixic acid (89.1%), doxycycline (83.1%), ceftria xone (70.3%), spectinomycin (67.7%), florfenicol (60.0%), cefotaxime (52.0%) and lomefloxacin (59.8%). The rates of resistance to multiple antibiotics in S. Derby and S.Typhimurium were higher than that in S. Enteritidis. However, the rate of resistance to fosfomycin were observed from higher to lower by S. Derby, S. Enteritidis, and S. Typhimurium. Biofilm formation ability analysis found that 88.49%of the Salmonella were able to produce biofilms, of which 236 Salmonella isolates were strong biofilm producer. Among the 26 types of antibiotics resistance genes (ARGs) were identified in this study, 4 ARGs (tetB,sul2,aadA2, and aph(3')-IIa) were highly prevalent. In addition, 5 β-lactam resistance genes (bla TEM, bla SHV, bla CMY-2, bla CTX-M, and bla OXA) and 7 quinolone resistance genes (oqxA, oqxB, qnrB, qnrC, qnrD, qnrS, and qeqA) were detected among these isolates. 12 out of 17 virulence genes selected in this study were commonly presented in the chromosomes of tested isolate, with a detection rate of over 80%, including misL, spiA, stn, pagC, iroN, fim, msgA, sopB, prgH, sitC, ttrC, spaN. This study provided a systematical updating on surveillance on prevalence of Salmonella from food animals in China, shedding the light on continued vigilance for Salmonella in food animals.

Characterization of the Biofilms Formed by Histamine-Producing Lentilactobacillus parabuchneri Strains in the Dairy Environment

Lentilactobacillus parabuchneri, a lactic acid bacterium, is largely responsible for the production and accumulation of histamine, a toxic biogenic amine, in cheese. L. parabuchneri strains can form biofilms on the surface of industry equipment. Since they are resistant to cleaning and disinfection, they may act as reservoirs of histamine-producing contaminants in cheese. The aim of this study was to investigate the biofilm-producing capacity of L. parabuchneri strains. Using the crystal violet technique, the strains were first categorized as weak, moderate or strong biofilm producers. Analysis of their biofilm matrices revealed them to be mainly composed of proteins. Two strains of each category were then selected to analyze the influence on the biofilm-forming capacity of temperature, pH, carbon source, NaCl concentration and surface material (i.e., focusing on those used in the dairy industry). In general, low temperature (8 °C), high NaCl concentrations (2-3% w/v) and neutral pH (pH 6) prevented biofilm formation. All strains were found to adhere easily to beech wood. These findings increase knowledge of the biofilm-forming capacity of histamine-producing L. parabuchneri strains and how their formation may be prevented for improving food safety.

Detection of biofilm-related genes and antibiotic resistance in Acinetobacter baumannii isolated from clinical specimens

Abstract. Saadulla SOK, Muhammed SM. 2023. Detection of biofilm-related genes and antibiotic resistance in Acinetobacter baumannii isolated from clinical specimens. Biodiversitas 24: 1809-1816. A total of 53 Acinetobacter baumannii clinical isolates were collected from patients treated at Shar Hospital in Sulaimani city to determine antibiotic susceptibility patterns and their association between biofilm formation and the distribution of biofilm-related genes. Identification of suspected A. baumannii was carried out by conventional and molecular approaches, including 16S rRNA and blaoxa-51 gene amplification. In addition, disk diffusion and microtiter plate methods determined antibiotic susceptibility and biofilm-forming capability, respectively. Out of 53 A. baumannii clinical isolates 42 (79.24%), were Multidrug-Resistant (MDR), of which 3 (5.66%) were resistant to colistin. Overall, 33 (62.26%) of the clinical isolates were strong biofilm producers, 6 (11.32%) were moderate or weak biofilm producers, and 8 (15.09%) were non-biofilm-forming isolates. The frequency of biofilm-related genes ompA, bap, csuE, blaPER-1, and cpaA among A. baumannii strains was 92.45%, 79.24%, 73.58%, 9.43%, and 7.54%, respectively. The high frequency of multi-drug resistant strains, and their ability to form biofilms, is a potential threat to effective therapy and may increase morbidity and mortality in infected patients. Colistin appeared to be the most effective antibiotic for treating MDR A. baumannii infections.

Study the Effect of Biofilm Production on Antibiotic Resistance in Proteus mirabilis Isolated from Clinical Samples in Kirkuk City

Proteus mirabilis is one of the most infectious organisms that inhabits the environment and causes a various infections involving those of the skin, respiratory tract, wounds and urinary tract. One of the main virulence features in P. mirabilis that plays a role in the pathogenesis and antibiotic resistance is the ability to form biofilm. The aim of study was to determine the relation between the antibiotic resistance and the biofilm formation by P. mirabilis. A total of (205) samples were collected from different clinical samples (urine, wound and burn swabs) in Kirkuk city hospitals. (32) Isolates were identified as P. mirabilis. Eight antibiotic discs were used for the antibiotic sensitivity test by disc diffusion method. Also, a micro titter plate method used for the detection of biofilm. The results of the antibiotic sensitivity showed variation in the rates of antibiotic resistance, doxycycline 29(90.6%), Trimethoprim- sulfamethaxole 27(84.37%), Ampicillin 22(68.75%) and amoxicillin/clavulanic 21(65.62%) resistance were found in the majority of the isolates. Gentamicin and cefotaxim (37.5%, 40.6%) respectively were moderate resistance, while Imipenem and Ciprofloxacin have low resistance and consider the most effective medication against P. mirabilis. The results showed 8 (25%) of P. mirabilis strong biofilm producer, 13 (41.6%) moderate biofilm producer, 8 (25%) weak biofilm producer and 3 (9.37%) non-biofilm producer. The study concluded that there is a link among biofilm production and antibiotic resistance.

STUDY OF EXTENDED SPECTRUM BETA LACTAMASES & BIOFILM IN PSEUDOMONAS SPECIES ISOLATED FROM DIFFERENT CLINICAL SAMPLES

Background:-Pseudomonas species are Gram negative bacteria which are resistant to commonly used antibiotics. Due to the formation of biofilm antimicrobial therapy is reduced & leads to chronic bacterial infections. Therefore, we need to isolate species of Pseudomonas from different clinical samples, detect ESBL & biofilm production in them. Objective:-1. To determine percentage of Pseudomonas species isolated from different clinical samples. 2. To determine the antibiogram of Pseudomonas species isolated from the samples. 3. To detect ESBL & biofilm production in Pseudomonas species. 4. To correlate biofilm & ESBL production. Method:-The susceptibility of different clinical samples of Pseudomonas spp.was determined by using antibiotics on Muller Hinton Agar by the Kirby -Bauer disk diffusion method using Clinical & Laboratory Standards Institute (CLSI) standards. Confirmatory test for ESBL production was done as per Clinical and Laboratory Standards Institute (CLSI) 2021guidelines. For the detection of biofilm Tissue Culture Plate (TCP) method was used. TCP is considered as the gold-standard method for biofilm detection. Result:-Out of total 171 Pseudomonas aeruginosa samples 30 were ESBL producers (17.5%) & 141 were Non ESBL Producers (82.5%), 12.8% were ESBL Producers & Strong Biofilm producers, 82.45% were Strong biofilm producers & Non ESBL producers. Conclusion:-Phenotypic detection of ESBL & antibiotic resistance in P.aeruginosa should be done & both the results should be taken in consideration for better representation of resistant strains, this will help clinicians to give appropriate antibiotics so that they can treat the infections timely.

Biofilm Production Ability of Streptococcus dysgalactiae Subsp. equisimilis: Associations with Host Species, Lancefield Group, Source, Clonal Complex, and Virulence-Associated Genes.

We assessed the biofilm production ability (BPA) of noninvasive Streptococcus dysgalactiae subsp. equisimilis (SDSE) in humans and companion animals and determined the relationship between bacterial populations with BPA and other host and microbiological features. Sixty-four isolates from companion animals and humans were collected along with host information. We measured BPA using crystal violet staining, in addition to emm typing, multilocus sequence typing, antimicrobial resistance (AMR) phenotyping/genotyping, and virulence-associated gene (VAG) detecting (prtF1-prtF2-lmb-cbp-sicG-srtp1-srtp2-brpA). Differences in the BPA of SDSE from different hosts and sources and different Lancefield groups were assessed. We analyzed the associations between populations with and without BPA (strong, moderate, weak, and no biofilm producers) and emm types, sequence types/clonal complexes (CCs), AMR phenotypes/genotypes, and VAG types. Seventeen, twenty-four, and twelve isolates were strong, moderate, and weak biofilm producers, respectively; eleven showed no BPA. There was a difference in the distribution of populations with BPA between human and animal origins and between isolates of groups G and C. We found an association between populations with BPA and the eye and ear source (vs. the pus and skin source). A relationship was observed between the populations with BPA and CC127 (vs. CC17). We observed no association between the populations with BPA and AMR phenotype/genotype. There was an association between the distribution of populations with BPA and srtp1 expression. Our observations suggest potential associations between populations with BPA and the host species, Lancefield group, source, CC, and VAG type.