<div>Background: Multi-drug resistant Escherichia coli (E. coli) can cause a variety of diseases that lead to considerable economic losses in the swine industry. In the past, the mainstream view believed that most bacterial resistance was caused by planktonic bacteria, but the ability of bacteria to form biofilms was ignored. Here, we isolated and identified 185 strains of E. coli from pigs in central China and analyzed the relationship between their genetics, antibiotic sensitivity and biofilm formation ability. 
 
Methods: First, the isolates were classified according to biofilm formation ability by semi-quantitative staining of crystal violet. Then, Phylogenetic group analysis of isolates by polymerase chain reaction. In addition, E. coli with different biofilm-forming abilities were evaluated for antimicrobial susceptibility in its planktonic and biofilm state. Finally, the drug resistance pattern of the isolates with different biofilm formation capabilities were compared. 
 
Result: most of the collected strains showed biofilm formation ability (87.57%, 162/185). The isolated E. coli with biofilm formation ability were classified into the following groups: A (16.05%, 26/162), B1 (10.49%, 17/162), B2 (33.33%, 54/162) and D (40.12%, 65/162). Simultaneously, the isolated E. coli were classified into the following groups according to the biofilm formation ability: Strong (34.57%, 56/162), Moderate (33.33%, 54/162), Weak (32.10%, 52/162) and Absent (12.43%, 23/162). Compared with the planktonic cells, the isolates showed a significant increase in the resistance rate in the biofilm form. And the isolates of the strong biofilm-forming ability group had a high drug resistance pattern. This study provides data of the drug resistance of pig-derived E. coli with different biofilm-forming abilities and provides a scientific basis for guiding veterinary clinical treatment and disease prevention.</div>

<div>Effect of Biofilm Formation on the Escherichia coli Drug Resistance of Isolates from Pigs in Central China</div>

<div>Background: Methicillin resistant Staphylococcus aureus (MRSA) refers to a group of gram-positive bacteria that are genetically distinct from other strains of Staphylococcus aureus that has developed, through horizontal gene transfer, natural selection and multiple drug resistance to beta lactam antibiotics and thus causing many severe diseases which are very problematic to treat as they are resistant to different antibiotics. The above situation is further aggravated by the formation of biofilms which are structured aggregation of surface attached microbes encased in an extracellular matrix. Thus, the time required to develop biofilms becomes an important point to study.&nbsp; 
 
Methods: In the present study, detection of the extent of biofilm formation by MRSA isolates, was performed using the Microtitre Plate Assay. The test was performed in triplicates and was continued for a time period of 7 days to detect the extent of biofilm formation with increase in incubation interval. 
 
Result: On comparing the biofilm forming ability of different isolates from Day 1 to Day 7, it could be clearly observed that the biofilm forming capacity of isolates gradually increased with increase in incubation time and most of the isolates became strong biofilm producers from Day 4.</div>

Effect of Incubation Time on the Biofilm Formation by Methicillin Resistant Staphylococcus aureus

<div>Background: Streptococcus uberis (S. uberis) is an environmental pathogen causing mastitis in Dairy cattle. It causes recurrent mastitis and reduction in milk production in livestock causing economic loss. The prevalence of S. uberis intramammary infections is due to ability of the organism to form biofilm in udder tissue. The present study is on in-vitro biofilm production, the correlation of luxS gene and the biofilm formation in S. uberis.&nbsp; 
 
Methods: A total of 91 mastitic milk samples were collected from cattle and buffaloes brought at Veterinary Hospitals and farms in Krishna, Guntur and West Godavari districts, Andhra Pradesh. The identification of the culture isolates was based on cultural and biochemical characteristics and confirmed by Polymerase Chain Reaction (PCR). The Streptococcus species cultures showing greyish, pinpointed colonies and/or aesculin hydrolysis on Edwards medium were further identified by various biochemical tests viz., catalase test, ninhydrin test, sodium hippurate hydrolysis test and type of haemolysis on 7% sheep blood agar. Confirmation of the isolates by PCR was followed by detection of biofilm formation using qualitative Congo red agar (CRA) method, quantitative microtiter plate (MTP) assay and biofilm gene (luxS) was detected using PCR. 
 
Conclusion: From this study it is suggestable that for biofilm study both phenotypic and genotypic methods should be taken together which can be influenced by various other factors also. MTP assay was a good choice for quantitative biofilm determination, which was giving a more accurate and understandable results. The results express that any of the isolates without luxS didn&rsquo;t produce a strong biofilm and it is concluded that there may be other genes for regulation of biofilm production and/or luxS gene has a regulatory role for one or more genes related to biofilm formation in S. uberis.</div>

<div>luxS Gene and Biofilm Formation in Streptococcus uberis Isolated from Bovine Mastitis Cases</div>

<div>Streptococcus suis (S. suis) is a major pathogen causing economic losses to the swine industry. Norfloxacins are usually used at sub-MIC (Minimum Inhibitory Concentration) doses to prevent S. suis infection. This study demonstrates the effect of norfloxacin sub-MIC on biofilm formation and virulence gene expression in S. suis.It was found that 1/4 MIC of norfloxacin increased biofilm formation in S. suis, the biofilms formed contained a higher number of viable bacteria. Additionally, bacterial growth rates were inhibited at 1/2 MIC of norfloxacin. Furthermore, the mRNA level of S. suis virulence gene cps, ef, sly, fpbs, gdh and gapdh increased by real-time PCR, while the virulence gene mrp decreased at 1/4 MIC. In conclusion, Norfloxacin sub-MICs affects biofilm formation and virulence gene expression in S. suis. These findings suggest that investigating the effect of the administration of antibiotics sub-MICs on bacterial biofilms and infection may lead to the development of future antibiotic treatments modalities.</div>

<div>Norfloxacin Sub-Inhibitory Concentration Affects Streptococcus suis Biofilm Formation and Virulence Gene Expression</div>

<div style="text-align:justify">Background: Antibiotic resistance is one of the major problems encountered in the therapy of canine pyometra. The ability of bacteria to form biofilm is implicated as one of the factors responsible for this. Escherichia coli and Staphylococcus aureus are the predominant bacteria associated with pyometra in canines and are known for their biofilm formation. Keeping in this view, a preliminary study was conducted to detect the biofilm forming strains of E. coli and S. aureus, if any, associated with canine pyometra. 
 
Methods: A total of 25 samples were collected, which included uterine discharges from cases of closed pyometra and anterior vaginal swabs from open pyometra. The isolates of E. coli and S. aureus were identified based on the cultural, morphological and biochemical characteristics. These isolates were subjected to antibiotic sensitivity test employing disc diffusion method. For biofilm detection, the isolates were screened by Congo red agar method, tube method and tissue culture plate method. 
 
Result: From 25 samples, two Streptococcus spp., thirteen&nbsp;Staphylococcus spp., seven E.coli, five Klebsiella spp. and two Pseudomonas spp. were isolated. All the isolates were found to be multi-drug resistant on antibiogram. The tissue culture plate and Congo red agar method was found more sensitive to detect the biofilm formation by S. aureus and E.coli isolates, respectively. The biofilm forming strains showed higher degree of antibiotic resistance in comparison with non-formers, indicating it as one of the major reasons for failure of antibiotic therapy in canine pyometra.</div>

Detection of Biofilm Formation by Escherichia coli and Staphylococcus aureus Associated with Canine Pyometra

<div>Background: Escherichia coli (E. coli) is a pathogen that sickens both humans and animals. There are relatively few reports on the correlation between drug resistance and biofilm formation ability of E.coli isolated from goose and fish in water environment of China. This study investigated the genetic typing, antibiotic sensitivity and biofilm formation ability of E. coli strains isolated from goose and fish. 
 
Methods: The phylogenetic clustering, drug resistance and biofilm formation ability of E. coli were tested by triple PCR, crystal violet microplate and Microdilution method.&nbsp; 
 
Result: The results showed the prevalence of group B2 and D in fish-derived E.coli accounted for 59% and 12%, goose-derived E. coli accounted for 48% and 9%, respectively. Some strains could form biofilm and biofilm formation ability was associated with the drug resistance. The MIC values of strains growing in biofilm were 2-16 times higher than those of corresponding planktonic bacteria. The antibiotic resistance among biofilm-forming isolates was significantly higher than that strains unable to form biofilm (p&lt;0.05).&nbsp;</div>

Phylogenetic Group, Biofilm Formation and Drug Resistance of Escherichia coli Isolated from Goose and Fish in Henan, China

<div style="text-align: justify;">The aim of the study was to detect Salmonella from coriander leaves by polymerase chain reaction, determine biofilm formation and antimicrobial resistance profiling of the isolates. Four Salmonella isolates were recovered from the total of 60 samples. The isolates were confirmed by PCR. The confirmed isolates were subjected for biofilm production assay and showed that all Salmonella isolates were able to form biofilm. Biofilm forming isolates were also subjected for antimicrobial resistance profiling. Three isolates were showed sensitivity against norfloxacin (92.5%). One was showing sensitivity against cefotaxime (90%). All the four isolates were showing complete resistant to ciprofloxacin, nalidixicacid, chloramphenical, gentamicin and cephalexin. Clindamycin and ofloxacin were showed sensitivity 20%. The finding of this study shows that coriander leaves are potential host for the transmission of Salmonella to human and animals. The ability of the isolates to form biofilm reveals the potential of the isolates to persist on the green leafy vegetables and the pathogenic status of the isolates as well as ability to resist antimicrobial chemotherapy.</div>

PCR based detection and Biofilm formation of Salmonella from fresh coriander leaves (Coriandrum sativum)

Background: Colibacillosis is an infectious disease that affects livestock such as cattle, pigs, goats, sheep, horses and poultry caused by the bacterium Escherichia coli. E. coli can form biofilms when environmental conditions are unfavorable. The purpose of this research is to determine the effect of honeybee propolis on the formation of E. coli biofilm in vitro.&nbsp; 
 
Methods: The research began with the dilution of propolis using the microdilution technique and determination of concentration values with a modified minimum inhibitory concentration (MIC). Biofilm inhibition assays were conducted in microplates with five propolis concentration treatments: 0.39 mg/mL, 0.78 mg/mL, 1.56 mg/mL, 3.125 mg/mL and 6.25 mg/mL, along with negative and positive controls, with eight replications. Subsequently, crystal violet quantification and absorbance value readings were done using an ELISA reader with a wavelength of 595 nm. 
 
Result: The results showed that between concentrations of 3.125 mg/mL, 6.25 mg/mL and the negative control, there was no significant difference with mean values of 0.09963, 0.078857 and 0.079375, respectively. Honeybee propolis extract has the potential to act as an antibiofilm against E. coli in vitro, with the minimum concentrations capable of inhibiting biofilm formation being 3.125 mg/mL and 6.25 mg/mL.

The Effect of Honeybee Propolis on Escherichia coli Biofilm Formation in vitro

<div>Background: The present study assessed the occurrence and biofilm forming potential of ESBL-producing Escherichia coli isolates recovered from raw salad vegetables collected from 32 retail vegetable shops of Mirzapur district, Uttar Pradesh, India (n=224). 
&nbsp; 
Methods: Standard bacteriological culture methods using cefotaxime-supplemented EMB agar were used for initial isolation of cefotaxime-resistant E. coli which were subjected to phenotypic detection of ESBL production by Kirby-Bauer disc diffusion test. Subsequently, all the phenotypically positive ESBL-producing E. coli isolates were subjected to determine their biofilm-producing ability by Congo red agar (CRA) assay and microtiter plate assay (MPA) followed by genotypic confirmation of biofilm production by PCR assay targeted at fim-H, Sfa and papC genes. Additionally, the isolates were genotypically explored for a potential presence of Shiga-like toxin genes (stx1 and stx2). 
&nbsp; 
Result: Altogether, 276 cefotaxime-resistant E. coli isolates were recovered, of which, 99.27% (274/276) were observed to be phenotypically positive for ESBL production. The brown, dry and rough (BDAR) and red, dry and rough (RDAR) colony morphotypes were observed by 70.80% (194/274) and 29.19% (80/274) of the isolates, respectively by CRA method revealing their potential to form biofilms. Biofilm formation was evident in 94.16% (258/274) of the isolates by MPA method, of which 79.45% (205/258), 17.05% (44/258) and 3.48% (9/258) were considered as weak, moderate and strong biofilm producers, respectively.&nbsp; The fimH gene was found to be the predominant genetic determinant of biofilm formation which was detected in 77% (211/274) of the tested isolates followed by Sfa gene (11.31%) and papC gene (4.01%). A significant difference (p&lt;0.05) was evident between CRA and MPA methods as well as phenotypic and genotypic methods for detection of biofilm formation among the recovered isolates. In addition, significant differences (p&lt;0.05) were also observed upon vegetable-wise comparison of ESBL-producing E. coli isolates and the presence of biofilm producing genes. The stx1 and stx2 genes were found to be present in one isolate recovered from a carrot sample and two isolates from coriander samples, respectively. . The findings of this study highlight the widespread occurrence of ESBL-producing E. coli from raw salad vegetables with significant biofilm-forming potential posing a public health risk. The detection of Shiga-like toxin genes in some isolates further underscores the need for stringent surveillance and improved hygiene practices to mitigate contamination risk in fresh produce.</div>

Assessment of Biofilm Formation and Shiga-like Toxin Genes in ESBL-producing E. coli Isolates Recovered from Retail Salad Vegetables in Mirzapur District, Uttar Pradesh, India

Background: Staphylococcus aureus is capable of producing a wide range of virulence factors. It is a deadly bacterium that is resistant to the majority of antibiotics that are typically provided. The ability of S. aureus to establish chronic, implant associated infections and our inability to cure them, is directly associated with its biofilm formation, creating an environment where bacteria can grow and persist while protected from the host immune response and antibiotic therapy. Antibiotic resistance of S. aureus is widely spreading with low cure rate.&nbsp; 
 
Methods: A total of 62 S. aureus strains were isolated from animal pus, human pus, animal skin, human skin, mastitic milk, normal milk and unprocessed meat samples. The isolates were genotypically confirmed by 23S rRNA ribotyping for S. aureus. Using 14 antibiotics belonging to different generations were tested for their resistance pattern from various sources.&nbsp; 
 
Result: All the mastitic milk, animal pus, human pus and unprocessed meat S. aureus isolates from all the places of sampling showed 100% sensitivity towards imipenem while isolates obtained from mastitic milk, human skin, animal skin showed 100% resistance towards ampicillin and ampicillin+sulbactum combination.