Biofilm Production Ability Research Articles

New Approach to Antifungal Activity of Fluconazole Incorporated into the Porous 6-Anhydro-α-l-Galacto-β-d-Galactan Structures Modified with Nanohydroxyapatite for Chronic-Wound Treatments-In Vitro Evaluation.

New fluconazole-loaded, 6-Anhydro-α-l-Galacto-β-d-Galactan hydrogels incorporated with nanohydroxyapatite were prepared and their physicochemical features (XRD, X-ray Diffraction; SEM-EDS, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy; ATR-FTIR, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy), fluconazole release profiles and enzymatic degradation were determined. Antifungal activity of pure fluconazole was tested using Candida species (C. albicans, C. tropicalis, C. glabarata), Cryptococcus species (C. neoformans, C. gatti) and Rhodotorula species (R. mucilaginosa, R. rubra) reference strains and clinical isolates. Standard microdilution method was applied, and fluconazole concentrations of 2–250 µg/mL were tested. Moreover, biofilm production ability of tested isolates was tested on the polystyrene surface at 28 and 37 ± 0.5 °C and measured after crystal violet staining. Strains with the highest biofilm production ability were chosen for further analysis. Confocal microscopy photographs were taken after live/dead staining of fungal suspensions incubated with tested hydrogels (with and without fluconazole). Performed analyses confirmed that polymeric hydrogels are excellent drug carriers and, when fluconazole-loaded, they may be applied as the prevention of chronic wounds fungal infection.

Staphylococcus aureus Isolated from Ruminants with Mastitis in Northern Greece Dairy Herds: Genetic Relatedness and Phenotypic and Genotypic Characterization.

Staphylococcus aureus is the most common mastitis-related pathogen in dairy cattle, goats, and sheep worldwide. However, the population structure and genomic characteristics of mastitis-associated S. aureus in small ruminants are limited. Furthermore, the genotypic and phenotypic characteristics involved in the pathogenicity of S. aureus have been thoroughly defined, yet their association with the severity of mastitis is not fully established. Here, we performed genotyping by pulsed-field gel electrophoresis (PFGE) and spa analyses to assess the genetic diversity and relatedness of 162 S. aureus strains recovered from clinical mastitis (CM) and subclinical mastitis (SCM) cases from goats, sheep, and bovines. PFGE analysis revealed 108 distinguishable pulsotypes and 3 main clusters that comprised isolates from the three host species, while according to spa typing, 32 different spa types were identified. Genotypic analysis revealed a spreading of genetically related or indistinguishable S. aureus strains among ovine, caprine, and bovine farms of distant geographical regions. In total, 28 different staphylococcal enterotoxin (SE) gene profiles were observed, revealing a diverse range of SE genes among isolates. By evaluating the antimicrobial resistance, we found low phenotypic antimicrobial resistance among all ruminant isolates. We also performed multiple correspondence analysis, which indicated that the presence of the sec gene, biofilm production, and high autoaggregation ability are associated with CM cases.

Antimicrobial and antibiofilm activities of marine sponge-associated bacteria against multidrug-resistant Staphylococcus spp. isolated from canine skin

Dogs play important roles in our society, thus the concern for their health becomes imperative. Staphylococcus spp. are commensal bacterium frequently isolated from canine skin and recognized as zoonotic agents. These bacteria have been becoming increasingly resistant to antimicrobials used to treat infections and to produce biofilm, which further increases their virulence capability and resistance. In this context, sponges-associated bacteria are known as prolific sources of substances with antimicrobial activities, representing a potential to integrate the arsenal of drugs for clinical use. In this study, 121 strains of Staphylococcus isolated from healthy or infected dogs were characterized according to their resistance to antimicrobials, as well as to their biofilm production ability. From the total of strains, 82 were resistant to at least one antimicrobial and 40 were multidrug-resistant (MDR). Furthermore, 117 out of 121 were capable to produce biofilm, and within those 36 were classified as strong biofilm producers. A set of fifteen bacterial strains previously isolated from marine sponges were also evaluated for antimicrobial and antibiofilm activities. Among the marine bacteria with antimicrobial activity, eight inhibited the growth of more than 50% of the MDR Staphylococcus. In addition, the cell-free supernatant obtained from five sponge-associated bacteria cultures was able to disaggregate more than 50% of the mature biofilm staphylococcal cells. The organic extracts (256 μg/mL) from two potential strains, Pseudomonas fluorescens H40 and H41, dissociated the biofilm of a strain classified as MDR and strong biofilm producer in 88.5% and 91.3%, respectively. These marine Pseudomonas strains also exhibited a strong activity of antimicrobial and antibiofilm substances. The results suggest that the sponge-associated bacteria analyzed could be potential sources of antimicrobial and antibiofilm substances against MDR and biofilm producers Staphylococcus isolated from canine skin.

Prevalence of Campylobacter Species in Diarrheal Samples of Children Less than 10 Years

Introduction: Campylobacter spp. is one of the most common causes of diarrheal diseases all over theworld, with a rapid acquisition of antibiotic resistance.Objective: Detect the frequency of Campylobacter species in diarrheal stool of children under ten years byconventional and molecular methods, and detect the bacterial ability to produce biofilm.Methods: A total of 200 children presented with diarrhea had been enrolled in this study. Campylobacterwas isolated and diagnosed primarily by characteristic features on Gram stain, culture media, biochemicaltests, and tested against 13 antibiotics by disc diffusion method. The ability of biofilm production wastested by crystal violet quantitative ELISA microtiter plate assays. Then Campylobacter spp was detectedby Multiplex PCR using species specific genes.Result: The prevalence of Campylobacter spp. was 17% by conventional methods and 15% by molecularmethod. The results of antibiotic susceptibility test showed that, there is complete resistance (100%)to cephalothin, ampicillin, and clindamycin for both species, full resistance (100%) to trimethoprimsulfamethoxazol and erythromycin by C.coli, and high resistance (92.3%) to trimethoprim-sulfamethoxazoland erythromycin by C.jejuni, while the lowest resistance was to nalidixic acid and amikacin (7.7%) byC.jejuni, and (12.5%) to tetracyclin, amoxicillin, amikacin, chloramphenicol, and ciprofloxacin by C.coli.The frequency of biofilm production in all positive Skirrow’s culture was (35.29%) as 12 out of 34 positiveisolates, ranging from mild to severe biofilm formation. By PCR assay, 64.7 % (22 of 34) positive Skirrow’sculture were also positive based on hipO gene specific for C.jejuni, while the prevalence of asp gene was(23.5%).Conclusion: The prevalence of Campylobacter spp. was 17% by conventional methods and 15% by molecularmethods, most of Campylobacter jejuni and Campylobacter coli isolates were MDR, and sensitive only tolimited number of antibiotics, many Campylobacter isolates produce biofilm, there was highly significantcorrelation between hippurate hydrolysis results and molecular detection of Campylobacter spp. dependingon hipO and asp genes.

Phenotypic characterization of Staphylococcus aureus isolated from foods of animal origin and other related sources

The present study aimed to phenotypically characterize S. aureus isolates originated from bovine raw milk and different steps of the pig slaughterhouse flowchart to evaluate the biofilm formation ability of these bacterial isolates, the factors that may influence this ability, the behavior of these bacterial pathogens in the food environment, and the sensitivity of these microorganisms to methicillin. In this survey, 28 S. aureus isolates were analyzed, seven of which originated from bovine raw milk, and 21 from swine samples. Biofilm production ability was observed in 57.1% (16/28) of the isolates tested corresponding to 85.7% (6/7) of bovine milk samples and 47.6% (10/21) of pig samples. Most of the isolates previously classified as strong biofilm formers maintained this ability after being exposed to different types of sublethal stress. Regarding the sensitivity of the isolates to methicillin, 42.9% (12/28) were resistant. Practical applications The practical applications are the phenotypic characterization of S. aureus, verification of biofilm formation by gifts present in the food industry, and of antimicrobial resistance of isolates.

Genetic analysis of methicillin-susceptible Staphylococcus aureus clinical isolates: High prevalence of multidrug-resistant ST239 with strong biofilm-production ability.

BackgroundThe distributions of methicillin‐susceptible Staphylococcus aureus (MSSA) are divers geographically with different genetic backgrounds. Data related to molecular characteristics of MSSA compare to methicillin‐resistant Staphylococcus aureus (MRSA) is sparse.MethodsIn this cross‐sectional study, antimicrobial susceptibility testing, virulence genes analysis, biofilm formation, accessory gene regulator (agr) typing, and multilocus sequence typing (MLST) characterized on 75 MSSA isolates.ResultsMultidrug‐resistance MSSA was found to be 84%. Forty‐eight (64%) isolates were toxinogenic with 34 and 14 isolates carrying pvl and tst representing 45.3% and 18.7%. The most common SE genes were sed (20%), sec (16%), and sea (16%). Fifty‐five (73.3%) isolates were confirmed as biofilm producer with a markedly high prevalence of fnbA (93.3%), fnbB (86.7%), icaA (65.3%), icaD (53.3%), can (24%), ebp (10.7%), and bap (1.3%). A total of 3 agr types (I, 73.3%; III, 16%; II, 10.7%) and 4 clonal complexes (CCs) and sequence types (STs), namely CC8/ST293 (45.3%), CC/ST22 (28%), CC/ST30 (16%), and CC/ST5 (10.7%) were detected in this study. All the high and low‐level mupirocin resistance strains belonged to ST239 and ST22 strains, respectively. All the fusidic acid‐resistant isolates carried fusC and belonged to ST30.ConclusionsThese findings indicated that ST239 with strong biofilm production ability is the most common type in MSSA strains isolated from patients. It seems that the antimicrobial resistance profiles, toxin, and biofilm formation were closely associated with specific STs. Further studies are required to identify and control of these clonal lineages in our area.

In vitro and in vivo Effect of Exogenous Farnesol Exposure Against Candida auris.

The spreading of multidrug-resistant Candida auris is considered as an emerging global health threat. The number of effective therapeutic regimens is strongly limited; therefore, development of novel strategies is needed. Farnesol is a quorum-sensing molecule with a potential antifungal and/or adjuvant effect; it may be a promising candidate in alternative treatment against Candida species including C. auris. To examine the effect of farnesol on C. auris, we performed experiments focusing on growth, biofilm production ability, production of enzymes related to oxidative stress, triazole susceptibility and virulence. Concentrations ranging from 100 to 300 μM farnesol caused a significant growth inhibition against C. auris planktonic cells for 24 h (p < 0.01–0.05). Farnesol treatment showed a concentration dependent inhibition in terms of biofilm forming ability of C. auris; however, it did not inhibit significantly the biofilm development at 24 h. Nevertheless, the metabolic activity of adhered farnesol pre-exposed cells (75 μM) was significantly diminished at 24 h depending on farnesol treatment during biofilm formation (p < 0.001–0.05). Moreover, 300 μM farnesol exerted a marked decrease in metabolic activity against one-day-old biofilms between 2 and 24 h (p < 0.001). Farnesol increased the production of reactive species remarkably, as revealed by 2′,7′-dichlorofluorescein (DCF) assay {3.96 ± 0.89 [nmol DCF (OD640)–1] and 23.54 ± 4.51 [nmol DCF (OD640)–1] for untreated cells and farnesol exposed cells, respectively; p < 0.001}. This was in line with increased superoxide dismutase level {85.69 ± 5.42 [munit (mg protein)–1] and 170.11 ± 17.37 [munit (mg protein)–1] for untreated cells and farnesol exposed cells, respectively; p < 0.001}, but the catalase level remained statistically comparable between treated and untreated cells (p > 0.05). Concerning virulence-related enzymes, exposure to 75 μM farnesol did not influence phospholipase or aspartic proteinase activity (p > 0.05). The interaction between fluconazole, itraconazole, voriconazole, posaconazole, isavuconazole and farnesol showed clear synergism (FICI ranges from 0.038 to 0.375) against one-day-old biofilms. Regarding in vivo experiments, daily 75 μM farnesol treatment decreased the fungal burden in an immunocompromised murine model of disseminated candidiasis, especially in case of inocula pre-exposed to farnesol (p < 0.01). In summary, farnesol shows a promising therapeutic or adjuvant potential in traditional or alternative therapies such as catheter lock therapy.

Biofilm Production Ability, Virulence and Antimicrobial Resistance Genes in Staphylococcus aureus from Various Veterinary Hospitals.

Staphylococcus aureus (S. aureus) is one of the most clinically important zoonotic pathogens, but an understanding of the prevalence, biofilm formulation ability, virulence, and antimicrobial resistance genes of S. aureus from veterinary hospitals is lacking. By characterizing S. aureus in different origins of veterinary hospitals in Guangzhou, China, in 2019, we identified with the presence of S. aureus in pets (17.1%), veterinarians (31.7%), airborne dust (19.1%), environmental surfaces (4.3%), and medical device surfaces (10.8%). Multilocus sequence typing (MLST) and Staphylococcus protein A (spa) typing analyses demonstrated methicillin-sensitive S. aureus (MSSA) ST398-t571, MSSA ST188-t189, and methicillin-resistant S. aureus (MRSA) ST59-t437 were the most prevalent lineage. S. aureus with similar pulsed-field gel electrophoresis (PFGE) types distributed widely in different kinds of samples. The crystal violet straining assays revealed 100% (3/3) of MRSA ST59 and 81.8% (9/11) of MSSA ST188 showed strong biofilm formulation ability, whereas other STs (ST1, ST5, ST7, ST15, ST88, ST398, ST3154 and ST5353) showed weak biofilm production ability. Polymerase chain reaction (PCR) confirmed the most prevalent leucocidin, staphylococcal enterotoxins, ica operon, and adhesion genes were lukD-lukE (49.0%), sec-sel (15.7%), icaA-icaB-icaC-icaR (100.0%), and fnbB-cidA-fib-ebps-eno (100.0%), respectively. Our study showed that the isolates with strong biofilm production ability had a higher prevalence in clfA, clfB, fnbA and sdrC genes compared to the isolates with weak biofilm production ability. Furthermore, 2 ST1-MRSA isolates with tst gene and 1 ST88-MSSA isolate with lukS/F-PV gene were detected. In conclusion, the clonal dissemination of S. aureus of different origins in veterinary hospitals may have occurred; the biofilm production capacity of S. aureus is strongly correlated with ST types; some adhesion genes such as clfA, clfB, fnbA, and sdrC may pose an influence on biofilm production ability and the emergence of lukS/F-PV and tst genes in S. aureus from veterinary hospitals should raise our vigilance.

Biofilm-Producing Ability and Antibiotic Resistance Pattern of Pathogenic Strains of Aeromonas hydrophila

Background: Interconnection among bacteria and other infectious agents can transfer the genetic elements such as antibiotic resistance genes. Biofilm or such an established structure could worsen when pathogenic bacteria are in the community. The recognition of bacterial behaviors and characteristics in biofilm community or planktonic forms such as antibiotic resistance spreading is an important and essential matter. Objectives: The current study aimed at investigating the correlation between biofilm-producing ability and antibiotic resistance patterns in some pathogenic strains of Aeromonas hydrophila. Methods: In this study, 19 strains of A. hydrophila isolated from infected carps with septicemia were identified by culture and biochemical tests. The isolated strains suspected as A. hydrophila were confirmed by duplex-PCR at both genus and species levels. The biofilm-producing ability of the confirmed isolates was evaluated by the microtiter plate crystal violet method. Antibiogram was designed for isolates by the Kirby-Bauer disc diffusion method. Results: All the strains were positive for biofilm production ability. Moderate and strong biofilm-producing abilities were detected in 79% and 21% of the isolates, respectively. The majority of the strains (90%) were resistant to clindamycin and vancomycin and all the strains (100%) were susceptible to ciprofloxacin and trimethoprim-sulfamethoxazole. Conclusions: Strong biofilm-producing strains were resistant to 75% of the studied antibiotics but moderate biofilm-producing strains had different susceptibility rates to the studied antibiotics. An important correlation was detected between the biofilm-producing level (moderate and strong) and antibiotic resistance against tetracycline, oxytetracycline, and amoxicillin. Because of the different ways of resistance acquisition in biofilm-producing bacteria, more studies are needed for understanding the main route.

Pseudomonas fluorescens Isolation from Green Salads and Antibiotic Susceptibilities of Isolates

Currently, leafy green salads are often consumed because they are considered as practical and healthy. However, during their preparation, both inadequate washing and contact with non-hygienic surfaces may increase their microbial load. This may cause several health problems for individuals consuming salads. The overuse of antibiotics has led to the emergence of multidrug resistant bacteria, including foodborne pathogens. Biofilm production ability of these pathogenic bacteria makes it difficult to treat infections caused by these pathogens. The aim of this study is to isolate and identify P. fluorescens from leafy green salads collected from different restaurants. A total of 72 isolates were isolated from leafy green salads, and 29 of these isolates were identified by PCR as Pseudomonas and 9 of them identified as P. fluorescens. All P. fluorescens isolates were resistant to ampicillin, amoxicillin, cefuroxime, ceftazidime and ceftriaxone antibiotics. The results of this study showed that additional attention for the hygiene conditions is needed during the preparation and storage stages of leafy green salads.

Aeromonas hydrophila from Fish and Humans: Biofilm Formation and Genetic Relatedness

A comprehensive study was done to determine the genetic relatedness and the biofilm formation ability of Aeromonas hydrophila strains (n=25) isolated from fish (150 tilapia and 144 mugil) and human stool samples (n=102). The results revealed that Random Amplification of Polymorphic DNA (RAPD-PCR) classified A. hydrophila strains into seven distinct profiles (R1-R7), the amplicon sizes ranged from 183-2930 bp. The isolates were grouped into five main clusters, the presence of isolates from fish and humans in the same cluster indicates the possibility of cross contamination. Biofilm results showed that 96% of A. hydrophila isolates were biofilm producers. At 35oC, 16 (64%) and 8 (32%) showed strong and moderate biofilm production ability, respectively. At 25oC, 21 (84%) were biofilm producers, of which, 8 (32%), 7 (28%) and 6 (24%) were strong, moderate and weak, respectively. At 4oC, decreased biofilm production ability was noticed 13 (52%), where 8 (32%) and 5 (20%) were moderate and weak biofilm producers, respectively. Significant correlation was showed between A. hydrophila isolates and different cultivation temperatures. This clarified the potential virulence of A. hydrophila isolates from both fish and human sources and their public health hazard.

Virulence genes profile and biofilm formation ability of Acinetobacter baumannii strains isolated from inpatients of a tertiary care hospital in southwest of Iran

Acinetobacter baumannii is an opportunistic pathogen which plays crucial roles in nosocomial infections and hospital outbreaks. The study aimed to determine the presence of virulence factors and the ability of biofilm production by isolated A. baumannii from hospitalized patients. The prevalence of A. baumannii in clinical samples was identified with standard biochemical tests. Polymerase chain reaction (PCR) was used for investigation of the presence of virulence factors in isolated strains. The isolates were assayed for biofilm formation by microtiter plate method. Totally, 100 clinical isolates of A. baumannii were collected. Although the presence of iutA (10%) and papC (5%) virulence genes was confirmed by PCR, isolated A. baumannii were negative for cnf1, cnf2, fbn, and kpsMT II virulence factors. Moreover, the quantification of biofilm production showed that 61% of the isolates were able to produce biofilm. Also, there was no relationship between the presence of iutA and papC genes and biofilm formation. In summary, we identified a high prevalence of biofilm formation among clinical isolates of A. baumannii in southwest of Iran, which could guarantee their persistence in the hospital environment. Our findings revealed that iutA and papC virulence genes which are associated with iron uptake and fimbriae can contribute to the pathogenesis of A. baumannii isolates in our region. It seems that effective infection control measures are essential to overcome the rapid dissemination of A. baumannii in our hospitals.

IN VITRO ASSESSMENT OF PHYSIOLOGICAL PROPERTIES OF ENTEROCOCCUS STRAINS OF HUMAN ORIGIN FOR POSSIBLE PROBIOTIC USE

Objective: The human vagina and gut are known to harbor a wide range of bacteria. Some useful bacteria maintain the vaginal pH around 3–4.5. This acidity of the vagina helps to inhibit pathogenic organisms that cause urogenital infections. The present study involved screening of previously identified Enterococcus strains of human origin for their probiotic physiological properties.&#x0D; Materials and Methods: The strains were screened for their biofilm, antibiofilm, antagonistic, antibiotic resistance, adherence, aggregating, and hydrogen peroxide production abilities.&#x0D; Results: Enterococcus canintestini S26B, Entamoeba dispar S27A, E. dispar S26A, E. dispar S20B, E. canintestini AB2, Enterococcus villorum SB2, and Enterococcus rivorum S22C displayed in vitro probiotic properties.&#x0D; Conclusions: These strains can be used as probiotic candidates and may prove their potential in human or animal feed only after further clinical studies.

Molecular detection of virulence factors and biofilm formation in Pseudomonas aeruginosa obtained from different clinical specimens in Bandar Abbas

Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen. The presence of several virulence factors such as exotoxin and exoenzyme genes and biofilm may contribute to its pathogenicity. The purpose of this study was to investigate the presence of toxA, exoU and exoS, the determination of biofilm production and antimicrobial susceptibility patterns among clinical isolates of P. aeruginosa. In this study, 75 isolates of P. aeruginosa were recovered from various clinical specimens. Antimicrobial susceptibility pattern of isolates were identified. Virulence genes toxA, exoU and exoS were determined using PCR. The ability of biofilm production was assessed. Antimicrobial susceptibility test showed that 12 strains were resistant to more than 8 antibiotics (17.14%). The most effective antibiotic was colistin as 98.6% of isolates were sensitive. The frequencies of exoU and exoS genes were detected as 36.6% and 55.7%, respectively. In addition, 98.6% of the isolates were biofilm producers. Exotoxin A was detected in sixty-eight isolates (95.7%). The findings of this study showed that, the presence of P. aeruginosa exotoxin and exoenzyme genes, particularly, the exoU gene is the most common virulence factors in the bacterial isolates from urine samples. Biofilm is a serious challenge in the treatment of P. aeruginosa infection.

Macrocolony of NDM-1 Producing Enterobacter hormaechei subsp. oharae Generates Subpopulations with Different Features Regarding the Response of Antimicrobial Agents and Biofilm Formation.

Enterobacter cloacae complex has been increasingly recognized as a nosocomial pathogen representing the third major Enterobacteriaceae species involved with infections. This study aims to evaluate virulence and antimicrobial susceptibility of subpopulations generated from macrocolonies of NDM-1 producing Enterobacter hormaechei clinical isolates. Biofilm was quantified using crystal violet method and fimbrial genes were investigated by PCR. Susceptibility of antimicrobials, alone and combined, was determined by minimum inhibitory concentration and checkerboard assays, respectively. Virulence and efficacy of antimicrobials were evaluated in Galleria mellonella larvae. Importantly, we verified that some subpopulations that originate from the same macrocolony present different biofilm production ability and distinct susceptibility to meropenem due to the loss of blaNDM-1 encoding plasmid. A more in-depth study was performed with the 798 macrocolony subpopulations. Type 3 fimbriae were straightly related with biofilm production; however, virulence in larvae was not statistically different among subpopulations. Triple combination with meropenem–rifampicin–polymyxin B showed in vitro synergistic effect against all subpopulations; while in vivo this treatment showed different efficacy rates for 798-1S and 798-4S subpopulations. The ability of multidrug resistant E. hormaechei isolates in generating bacterial subpopulations presenting different susceptible and virulence mechanisms are worrisome and may explain why these infections are hardly overcome.

Efficacy of Lactobacillus ssp. in inhibiting the biofilm skin infections induced by Staphylococcus aureus pathogen

Background and aim: The escalating prevalence of Methicillin-Resistant Staphylococcus aureus (MRSA) has become a major public health threat. While lactobacilli were recently found useful in fighting various pathogens, limited data exist on their therapeutic potential for S. aureus infections. The aim of this study is to determine whether Lactobacillus Cell Free Supernatants (LCFS) were able to inhibit the biofilm produced by S. aureus. Material and methods: A total of 36 Staphylococcal bacteria were isolated from infected skin's patients. Antimicrobial susceptibility pattern of all tested isolates were determined using disk diffusion method. Biofilm production ability was detected using the Congo Red Agar (CRA) and the Microtitre Plate (MtP) assays. Furthermore, the efficacy of Lactobacillus CFS in inhibiting the biofilm skin infections induced by S. aureus isolates was estimated using MtP method. Results: Out of 36 S. aureus isolates, 34 (94.4%) and 20 (55.5%) showed positive results using CRA or MtP, respectively. All isolates showed high resistance against cefepime (97%), whereas imipenem was the most effective antibiotic against bacterial isolates. CFS exhibited significant anti-biofilm activities against the tested isolates. Conclusion: CFS of Lactobacillus spp. presents potential and safe alternative to synthetic antibiotics for inhibiting the biofilm skin infections induced by S. aureus.

ENDOSYMBIONTS OF ENTOMOPATHOGENIC NEMATODES FROM SOUTH ITALY: A PHENOTYPIC STUDY

We examined different Xenorhabdusstrains (five of X. bovieniiand two of X. kozodoii), obtained from EPNisolates belonging to the genus Steinernema(S. feltiae, S. ichnusae, S. apuliae, S. vulcanicum) of different geographicorigin by both genotypic and phenotypic analysis. Common laboratory assays were done for traits such as antibioticresistance, haemolytic activity, lactose utilisation, biofilm production, chosen as the least selectable traits for EPN life-cycle, and thus as (presumably) neutral traits. As selective marker, the activity of the endosymbiont’s toxins was verified inan in vivoassay on G. mellonellalarvae. Genotyping done by 16S partial sequencing was used for identification purposes.Xenorhabdusbovieniiisolates showed a broad phenotypic spectrum; on the other hand, X. kozodoiishowed a less degreeof phenotypic variation, reduced ability of biofilm production and conspicuous β-galactosidase activity. However, all thestrains were able to kill G. mellonellalarvae with high efficiency.

Multidrug-resistant Staphylococcus pettenkoferi isolated from cat in India.

Background and Aim:Coagulase-negative staphylococci (CoNS) are considered to be one of the emerging pathogens in human and animals in recent times. Staphylococcus pettenkoferi, a novel pathogen under CoNS, is discovered in 2002 in humans with multiple clinical manifestations in various patients. To date, the pathogens have not yet been reported from any animals. The present study reported the first ever isolation, identification, and characterization of multidrug-resistant S. pettenkoferi from a cat with peritonitis in India.Materials and Methods:Peritoneal fluid was collected aseptically from 3 years old cat processed for bacteriological culture by standard techniques. Isolates were confirmed by BD Phoenix™ automated bacterial identification system and were subjected to plate and tube coagulase tests. All the isolates were tested for antimicrobial sensitivity profile by disc diffusion assay, extended-spectrum β-lactamase production by double disc diffusion assay, in vitro biofilm production ability by microtiter plate assay, and detection of virulence genes and mecA gene by polymerase chain reaction assay.Results:A total of five clonally expanded isolates of S. pettenkoferi were isolated from peritoneal fluid of the affected cat. All the isolates were resistant against 36 antimicrobial agents and were also methicillin-resistant staphylococci. Phenotypically, all the isolates were negative for biofilm production but were carrying multiple biofilm-producing genes (icaA, IS257, nuc, and mecA).Conclusion:Although S. pettenkoferi was previously reported once from animal (cat) environment, this is probably the first ever report of isolation of the organism directly from any animals. This is also probably the first report from any species in India.

Biofilm Formation by Staphylococcus aureus Isolated from Food Contact Surfaces in the Dairy Industry of Jalisco, Mexico

Staphylococcus aureus is an important food-borne pathogen able to form biofilms. This pathogen is responsible for outbreaks of food-borne illnesses associated with the consumption of milk and dairy products. The aim of this study was to evaluate the biofilm-forming ability of S. aureus isolates, recovered from food contact surfaces in the dairy industry of Jalisco, Mexico. A total of 84 S. aureus strains were evaluated. The isolates were characterized phenotypically by culture on Congo red agar plates. The ability of the strains to form biofilms was investigated in 96-well flat-bottomed microtiter polystyrene plates. Stainless-steel coupons were used as an experimental surface. Biofilm formation was observed, using epifluorescence microscopy and scanning electron microscopy. Detection of the icaADBC genes in S. aureus was performed by the PCR technique. A total of 52.3% (44/84) of the S. aureus strains contained the icaADBC gene that synthesizes polysaccharide intercellular adhesion (PIA) molecules. On Congo red agar, 75% (63/84) of the S. aureus isolates were biofilm producers, 16.6% (14/84) were non-biofilm formers, and 8.3% (7/84) showed a noncharacteristic phenotype. The biofilm production of the S. aureus strains SA-4E, SA-9, SA-13, and SA-19 on stainless-steel coupons was investigated at 25°C for 8 days, and the detected cell population density was approximately 7.15–7.82 log CFU cm−2. In addition to the ability of biofilm production, it is important to highlight that these strains are potential enterotoxin producers as se genes have been previously detected in their genomes. A part of the ability of biofilm production and the determination of the presence of virulence determinants in the genome of S. aureus can contribute to the pathogenicity of strains. Therefore, vigilant food safety practices need to be implemented in the dairy industries regarding FCS to prevent food-borne infections and intoxications due to S. aureus contamination.

Microterracettes in Sabkha Oum Dba (Western Sahara, Morocco): Physical and Biological Interactions in the Formation of a Surface Micromorphology.

Small-scale terracing (microterracettes) is a surface geomorphic feature that recurs under a range of environmental settings, such as those existing in high to low temperature geothermal springs and evaporitic environments, through the single or combined action of physicochemical agents and microbiological processes. Such morphology can also be observed in a confined sector of the Sabkha Oum Dba, which is an inland sabkha of the Western Sahara (Morocco), where field and laboratory investigations revealed that they primarily depend on the accumulation of naviculoid diatoms. Through their biofilm production ability, these benthic diatoms are able to stabilize surface morphologies and make organic alveolar frameworks where the precipitation of low Mg calcite occurs in areas subjected to active oxygenic photosynthesis. Because microterracettes arise in a specific set of environmental conditions, they have environmental significance and, thanks to a high fossilization potential due to mineral precipitation, they can be an effective source of biomorphological and chemical evidence for life. The relationship with aqueous environments, considered to be widespread on Mars especially during a period of intense hydrologic activity as in the late Noachian and Hesperian periods, make the understanding of surficial processes useful (such as the formation of microterracettes) whose formation is frequent in terrestrial analogues for martian environments, such as ephemeral saline continental lakes (sabkhas) and related to the products of bacterial and eukaryotic life, as in the case of biofilms, in search for similar life forms beyond Earth.