CHARACTERIZATION OF BIOFILM FORMED ON INTRAUTERINE DEVICES

Effects of propolis coating on antibacterial resistance of intrauterine devices

Intrauterine devices (IUDs) are widely used in preventing fertilization as contracepting devices. In market, they are produced as T-shaped polyethylene (or propylene) and metal (especially copper) composites. Although the metal component is utilized to provide antibacterial efficacy, prolonged implantation and the presence of a wide range of bacteria flora in the intrauterine environment make IUDs susceptible to bacterial contamination, biofilm formation, and unpleasant infection. In the presented study, the propolis, a natural anti-bacterial/-viral product used for different biomedical applications, coating strategy was applied comparatively in three different ways: coating directly on metal components, coating on polymeric material, and using carrying polymer. In addition, antibacterial activity against Gram-positive (Staphylococcus aureus, S. aureus) and Gram-negative (Escherichia coli, E. coli) bacterial strains were investigated by both dynamic bacterial culture (bacterial inhibition activity) and biofilm (biofilm formation resistance) tests. As a result of 48 h of dynamic bacterial culture; it was determined that the antibacterial inhibition efficiency depending on propolis concentration increased up to 99.5% and 98.5% for E. coli and S. aureus, respectively. In addition, the carrying polymer allows IUDs to cover surfaces more homogeneously, as well as improve antibacterial activity. Similarly; it was determined that biofilm formation resistance was improved by 44.33% for E. coli and by 45.99% for S. aureus with both the propolis concentration and the use of carrying polymer. As a result, it has been revealed that propolis will be classified as an alternative, promising, and effective coating agent for improving antibacterial properties and biofilm formation resistance of IUDs.

Microbial Biofilm: A Review on Formation, Infection, Antibiotic Resistance, Control Measures, and Innovative Treatment

Biofilm is complex and consists of bacterial colonies that reside in an exopolysaccharide matrix that attaches to foreign surfaces in a living organism. Biofilm frequently leads to nosocomial, chronic infections in clinical settings. Since the bacteria in the biofilm have developed antibiotic resistance, using antibiotics alone to treat infections brought on by biofilm is ineffective. This review provides a succinct summary of the theories behind the composition of, formation of, and drug-resistant infections attributed to biofilm and cutting-edge curative approaches to counteract and treat biofilm. The high frequency of medical device-induced infections due to biofilm warrants the application of innovative technologies to manage the complexities presented by biofilm.

Vaginal Tampon Colonization by Staphylococcus aureus in Healthy Women

Tampons recovered from a cohort of 737 healthy women (median age, 32 years) were analyzed for the presence of Staphylococcus aureus A total of 198 tampons (27%) were colonized by S. aureus, 28 (4%) by a strain producing toxic shock syndrome toxin 1 (TSST-1). S. aureus was detected more frequently in tampons that did not require an applicator for their insertion (74/233 [32%] versus 90/381 [24%]; odds ratio [OR] = 1.51 [95% confidence interval, 1.04 to 2.17]) and in women who used an intrauterine device for contraception (53/155 [34%] versus 145/572 [27%]; OR = 1.53 [95% confidence interval, 1.05 to 2.24]). The S. aureus strains isolated from tampons belonged to 22 different clonal complexes (CCs). The most prevalent CC was CC398 agr1 (n = 57 [27%]), a clone that does not produce superantigenic toxins, followed by CC30 agr3 (n = 27, 13%), producing TSST-1 (24/27 [89%]), the principal clone of S. aureus involved in menstrual toxic shock syndrome (MTSS).IMPORTANCE Menstrual toxic shock syndrome (MTSS) is an uncommon severe acute disease that occurs in healthy menstruating women colonized by TSST-1-producing S. aureus who use intravaginal protection, such as tampons and menstrual cups. The catamenial product collected by the protection serves as a growth medium for S. aureus and allows TSST-1 production. Previous studies evaluated the prevalence of genital colonization by S. aureus by vaginal swabbing, but they did not examine tampon colonization. This study demonstrated a high prevalence of tampon colonization by S. aureus and the presence of the CC30 TSST-1 S. aureus clone responsible for MTSS in tampons from healthy women. The results support the vaginal carriage of this lineage in healthy women. In addition, the higher prevalence of S. aureus within tampons that do not require an applicator indicates a crucial role for handwashing before tampon handling to decrease the risk of tampon contamination.

Effect of intrauterine device insertion on Candida species in cervicovaginal specimen identified by polymerase chain reaction technic: A longitudinal study on Iranian women

AIM

To assess the effects of copper T-380-A intrauterine device (IUD) insertion on Candida species in cervicovaginal specimen by a molecular method, polymerase chain reaction.

METHODS

This is a longitudinal prospective study performed on 95 women attending Health Centers of Tehran, Iran in 2012, who selected copper T-380-A IUD for contraception and had no history of local or systemic antibiotics or antifungals use during the previous 2 weeks. Cervicovaginal specimens were twice collected and cultured on Sabouraud dextrose agar and CHROMagar Candida, before and 3 months after IUD insertion. Finally, a molecular method, PCR-RFLP was performed for identification of Candida species. P-values <0.05 were considered significant.

RESULTS

The mean age of participants was 28 ± 7.44 years. Positive Candida cultures were significantly increased 3 months after IUD insertion (25.3% vs 11.6%, P = 0.007). The most common identified species before and after IUD insertion, were Albicans, Glabrata and then both 'Albicans & Glabrata', respectively. The prevalence of Albicans and Glabrata decreased, while both 'Albicans & Glabrata' increased insignificantly.

CONCLUSION

There was more than about fourfold increase in positive Candida cultures after IUD insertion. As the prevalence of simultaneous infection with both 'Albicans & Glabrata' species which are resistant to usual treatment, increased, it seems necessary to provide more intensive follow-up care for IUD users.

Biofilms and vulvovaginal candidiasis

Candida species, including C. albicans, are part of the mucosal flora of most healthy women, and inhabit the gastrointestinal and genitourinary tracts. Under favourable conditions, they can colonize the vulvovaginal mucosa, giving rise to symptomatic vulvovaginal candidiasis (VVC). The mechanism by which Candida spp. produces inflammation is unknown. Both, the blastoconidia and the pseudohyphae are capable of destroying the vaginal epithelium by direct invasion. Although the symptoms are not always related to the fungal burden, in general, VVC is associated with a greater number of yeasts and pseudohyphae. Some years ago, C. albicans was the species most frequently involved in the different forms of VVC. However, infections by different species have emerged during the last two decades producing an increase in causative species of VVC such as C. glabrata, C. parapsilosis, C. krusei and C. tropicalis. Candida species are pathogenic organisms that have two forms of development: planktonic and biofilm. A biofilm is defined as a community of microorganisms attached to a surface and encompassed by an extracellular matrix. This form of presentation gives microorganisms greater resistance to antifungal agents. This review, about Candia spp. with a special emphasis on Candida albicans discusses specific areas such as biofilm structure and development, cell morphology and biofilm formation, biofilm-associated gene expression, the cell surface and adherence, the extracellular matrix, biofilm metabolism, and biofilm drug resistance in vulvovaginitis biofilms as an important virulence factor in fungi.

Contraceptive rings promote vaginal lactobacilli in a high bacterial vaginosis prevalence population: A randomised, open-label longitudinal study in Rwandan women

Background

Hormonal contraception has been associated with a reduced risk of vaginal dysbiosis, which in turn has been associated with reduced prevalence of sexually transmitted infections (STIs), including HIV. Vaginal rings are used or developed as delivery systems for contraceptive hormones and antimicrobial drugs for STI and HIV prevention or treatment. We hypothesized that a contraceptive vaginal ring (CVR) containing oestrogen enhances a lactobacilli-dominated vaginal microbial community despite biomass accumulation on the CVR’s surface.

Methods

We enrolled 120 women for 12 weeks in an open-label NuvaRing^® study at Rinda Ubuzima, Kigali, Rwanda. Vaginal and ring microbiota were assessed at baseline and each ring removal visit by Gram stain Nugent scoring (vaginal only), quantitative PCR for Lactobacillus species, Gardnerella vaginalis and Atopobium vaginae, and fluorescent in situ hybridization to visualize cell-adherent bacteria. Ring biomass was measured by crystal violet staining.

Results

Bacterial vaginosis (BV) prevalence was 48% at baseline. The mean Nugent score decreased significantly with ring use. The presence and mean log₁₀ concentrations of Lactobacillus species in vaginal secretions increased significantly whereas those of G. vaginalis and presence of A. vaginae decreased significantly. Biomass accumulated on the CVRs with a species composition mirroring the vaginal microbiota. This ring biomass composition and optical density after crystal violet staining did not change significantly over time.

Conclusions

NuvaRing^® promoted lactobacilli-dominated vaginal microbial communities in a population with high baseline BV prevalence despite the fact that biomass accumulated on the rings.

The fallopian tube microbiome: implications for reproductive health

Objective

There is a paucity of data characterizing the microbiota of the female upper genital tract, which controversially is described as a sterile site. We examine whether the fallopian tube harbours an endogenous microbial community.

Design

This prospective study collected from women undergoing total hysterectomy or salpingectomy-oophorectomy.

Setting

Private hospital gynaecology department.

Patients

Fallopian tubes were collected from women diagnosed with benign disease or for prophylaxis.

Interventions

Samples were interrogated for the presence of microbial DNA using a next generation sequencing technology approach to exploit the V5 to V9 regions of the 16S rRNA gene.

Main outcome measures

The fallopian tube microbiota was characterized using traditional culture techniques and next generation sequencing.

Results

Bacteria were isolated from 50% of cultured samples, and 100% of samples returned positive PCR results. Only 68% of the culture isolates could be confidently identified using automated diagnostic equipment in a clinical microbiology laboratory. Monomicrobial communities were identified only for cultured isolates (50%). Pyrosequencing revealed that all communities were polymicrobial. Lactobacillus spp. were not present in all groups, nor were they the most dominant isolates. Distinct differences in the microbial communities were evident for left compared to right fallopian tubes, ampulla versus isthmus, pre- and post- menopausal tissue, and in secretory phase fallopian tubes with and without Mirena intrauterine devices in situ (all p < 0.05).

Conclusion

The female upper genital tract is not sterile. Distinct microbial community profiles in the fallopian tubes of healthy women suggest that this genital tract site supports an endogenous microbiota.

Herpes simplex virus-1 entrapped in Candida albicans biofilm displays decreased sensitivity to antivirals and UVA1 laser treatment

BACKGROUND

Recently, we published data suggesting a mutualistic relationship between HSV-1 and Candida. albicans; in particular: (a) HSV-1 infected macrophages are inhibited in their anti-Candida effector function and (b) Candida biofilm protects HSV-1 from inactivation. The present in vitro study is aimed at testing the effects of Candida biofilm on HSV-1 sensitivity to pharmacological and physical stress, such as antiviral drugs (acyclovir and foscarnet) and laser UVA1 irradiation. We also investigated whether fungus growth pattern, either sessile or planktonic, influences HSV-1 sensitivity to antivirals.

METHODS

Mature Candida biofilms were exposed to HSV-1 and then irradiated with laser light (UVA1, 355 λ). In another set of experiments, mature Candida biofilm were co-cultured with HSV-1 infected VERO cells in the presence of different concentrations of acyclovir or foscarnet. In both protocols, controls unexposed to laser or drugs were included. The viral yield of treated and untreated samples was evaluated by end-point titration. To evaluate whether this protective effect might occur in relation with a different growth pattern, HSV-1 infected cells were co-cultured with either sessile or planktonic forms of Candida and then assessed for susceptibility to antiviral drugs.

RESULTS

UVA1 irradiation caused a 2 Log reduction of virus yield in the control cultures whereas the reduction was only 1 Log with Candida biofilm, regardless to the laser dose applied to the experimental samples (50 or 100 J/cm²). The presence of biofilm increased the IC₉₀ from 18.4-25.6 J/cm². Acyclovir caused a 2.3 Log reduction of virus yield in the control cultures whereas with Candida biofilm the reduction was only 0.5 Log; foscarnet determined a reduction of 1.4 Log in the controls and 0.2 Log in biofilm cultures. Consequently, the ICs₅₀ for acyclovir and foscarnet increased by 4- and 12-folds, respectively, compared to controls. When HSV-1 was exposed to either sessile or planktonic fungal cells, the antiviral treatments caused approximately the same weak reduction of virus yield.

CONCLUSIONS

These data demonstrate that: (1) HSV-1 encompassed in Candida biofilm is protected from inactivation by physical (laser) and pharmacological (acyclovir or foscarnet) treatments; (2) the drug antiviral activity is reduced at a similar extent for both sessile or planktonic Candida.

Bacterial biofilms in the vagina

A bacterial biofilm is a structured community of bacteria in a self-produced extracellular matrix, adherent to an inert surface or biological tissue. The involvement of biofilm in a bacterial infection implies that the infection is difficult to treat and that the patient will probably experience relapses of the condition. In bacterial vaginosis (BV), the lactobacilli concentration decreases, while the bacterial load of other (facultative) anaerobic bacteria increases. A hallmark of BV is the presence of clue cells, now known as the result of a polymicrobial biofilm formed in vaginal epithelial cells. Current knowledge of the individual roles of bacterial species involved in polymicrobial BV biofilms or interactions between these species are not fully known. In addition, knowledge of the composition matrix and triggers of biofilm formation is still lacking. Bacteria are able to attach to the surface of indwelling medical devices and cover these surfaces with biofilm. Vaginally inserted devices, such as tampons, intra-uterine devices and vaginal rings, can also be colonized by bacteria and be subjected to biofilm formation. This might hamper release of active product in case of drug-releasing devices such as vaginal rings, or promote the presence of unfavorable bacteria in the vagina. This paper reviews current knowledge of biofilms in the vaginal environment.

Vulvovaginal candidiasis: Epidemiology, microbiology and risk factors

Vulvovaginal candidiasis (VVC) is an infection caused by Candida species that affects millions of women every year. Although Candida albicans is the main cause of VVC, the identification of non-Candida albicans Candida (NCAC) species, especially Candida glabrata, as the cause of this infection, appears to be increasing. The development of VVC is usually attributed to the disturbance of the balance between Candida vaginal colonization and host environment by physiological or nonphysiological changes. Several host-related and behavioral risk factors have been proposed as predisposing factors for VVC. Host-related factors include pregnancy, hormone replacement, uncontrolled diabetes, immunosuppression, antibiotics, glucocorticoids use and genetic predispositions. Behavioral risk factors include use of oral contraceptives, intrauterine device, spermicides and condoms and some habits of hygiene, clothing and sexual practices. Despite a growing list of recognized risk factors, much remains to be elucidated as the role of host versus microorganisms, in inducing VVC and its recurrence. Thus, this review provides information about the current state of knowledge on the risk factors that predispose to VVC, also including a revision of the epidemiology and microbiology of VVC, as well as of Candida virulence factors associated with vaginal pathogenicity.

Microbiological profile and biofilm formation on removed intrauterine contraceptive devices from a sample of Egyptian women

AIM

The aim of this study was to investigate the presence of biofilm formation around intrauterine contraceptive devices (IUCD) and to correlate the microbiological profile of the IUCD-associated genital infections to the microbiological profile of specimens retrieved from vaginal discharge.

MATERIAL AND METHODS

Samples of the vaginal discharge in the posterior fornix were collected from 50 women attending the Family Planning Clinic in Ain Shams University Hospital using two high vaginal swabs. Swabs were immediately sent for Gram staining as well as microbiological culture. The IUCD was then removed. A 0.5-cm piece of the removed IUCD was cut and sent for culture. Growing colonies were tested for their abilities to form a biofilm (colorimetric method). Another 0.5-cm piece of the removed IUCD was examined by electron microscopy (EM) for detection of biofilm formation.

RESULTS

Among the included 50 women, 24 (48%) women showed biofilm formation (via colorimetric methods). EM scanning was able to detect biofilm formation in the prepared pieces of the removed IUCD of 48 (96%) women. There was no significant agreement between the isolated microorganisms on the removed IUCD and the vaginal swab (proportion of agreement was 14 [11.4%]; κ = -0.089, P = 0.892).

CONCLUSION

Scanning EM is a useful tool in detection of biofilm formation on removed IUCD.

Patterns of Candida biofilm on intrauterine devices

Biofilms are colonies of microbial cells encased in a self-produced organic polymeric matrix and represent a common mode of microbial growth. Microbes growing as biofilm are highly resistant to commonly used antimicrobial drugs. We aimed to screen and characterize biofilm formation by different isolates of Candida on removed intrauterine devices (IUDs), to perform experimental biofilm formation with isolated strains, and to examine biofilm by the crystal violet and XTT reduction assays and scanning electron microscopy (SEM). A total of 56 IUDs were examined for biofilm formation using Sabouraud's dextrose chloramphenicol agar. Suspected colonies were identified by different methods. Antifungal susceptibility testing with fluconazole (FLU) and amphotericin B for the isolated strains and in vitro experimental biofilm formation was carried out. The biofilm was quantified by crystal violet, XTT reduction assay and SEM. Among the 56 IUDs investigated, 26 were Candida positive (46.4 %). Candida albicans was recovered from 15 isolates. The biofilm MIC of FLU was increased 64 to 1000 times compared to the MIC for planktonic cells. The XTT method results were dependent on the Candida species; biofilm formation was highest in Candida krusei and Candida glabrata strains, followed by C. albicans and Candida tropicalis. SEM of Candida biofilm revealed a heterogeneous thick biofilm with a mixture of micro-organisms. The main conclusion from this study was non-albicans Candida represents more than a half of the Candida biofilm. Better understanding of Candida biofilms may lead to the development of novel therapeutic approaches for the treatment of fungal infections, especially resistant ones among IUD users.

Does removal of CU-IUD in patients with biofilm forming candida really maintain regression of clinical symptoms?

OBJECTIVE

To evaluate whether symptoms and recurrence would differ with and without Cu-IUD removal in patients with concomitant biofilm forming Candida spp.

METHODS

The data of 270 consecutive patients wearing TCu380A Cu-IUD were evaluated. Among these patients, 100/270 were found to have Candida spp. isolated from the tail of Cu-IUD or vaginal samples. These patients were investigated in four groups: Group 1 (n = 24; Biofilm (+), Cu-IUD removed), Group 2 (n = 14; Biofilm (+), Cu-IUD not removed), Group 3 (n = 29; Biofilm (-), Cu-IUD removed), Group 4 (n = 33; Biofilm (-), Cu-IUD not removed). Patients in each group were followed for clinical signs and symptoms for 8-16 months and compared to each other.

RESULTS

Symptoms, physical findings and candida positivity have decreased statistically significantly in Group 1 one year after removal of Cu-IUD (95.8% vs. 4.2%, p < 0.01; 95.8% vs. 4.2%, p < 0.01; 100% vs. 8.3%, p < 0.01 respectively). In Group 2, symptoms, physical findings and candida positivity have decreased after follow-up, but without a statistical significance. In Group 3, all the parameters have decreased, but only decrease in candida positivity has reached statistical significance (100% vs. 48.3%, p < 0.01). In Group 4 - as in Group 1- symptoms, physical findings and candida positivity have decreased statistically significantly (48.5% vs. 18.2%, p = 0.01; 72.7% vs. 48.5%, p = 0.05; 100% vs. 51.5%, p < 0.01 respectively).

CONCLUSION

Biofilm forming microorganisms should be considered in the management of vaginal infections or symptoms for safer use of intrauterine devices.

The biology of Neisseria adhesins

Members of the genus Neisseria include pathogens causing important human diseases such as meningitis, septicaemia, gonorrhoea and pelvic inflammatory disease syndrome. Neisseriae are found on the exposed epithelia of the upper respiratory tract and the urogenital tract. Colonisation of these exposed epithelia is dependent on a repertoire of diverse bacterial molecules, extending not only from the surface of the bacteria but also found within the outer membrane. During invasive disease, pathogenic Neisseriae also interact with immune effector cells, vascular endothelia and the meninges. Neisseria adhesion involves the interplay of these multiple surface factors and in this review we discuss the structure and function of these important molecules and the nature of the host cell receptors and mechanisms involved in their recognition. We also describe the current status for recently identified Neisseria adhesins. Understanding the biology of Neisseria adhesins has an impact not only on the development of new vaccines but also in revealing fundamental knowledge about human biology.

Hormone-dependent bacterial growth, persistence and biofilm formation--a pilot study investigating human follicular fluid collected during IVF cycles

Human follicular fluid, considered sterile, is aspirated as part of an in vitro fertilization (IVF) cycle. However, it is easily contaminated by the trans-vaginal collection route and little information exists in its potential to support the growth of microorganisms. The objectives of this study were to determine whether human follicular fluid can support bacterial growth over time, whether the steroid hormones estradiol and progesterone (present at high levels within follicular fluid) contribute to the in vitro growth of bacterial species, and whether species isolated from follicular fluid form biofilms. We found that bacteria in follicular fluid could persist for at least 28 weeks in vitro and that the steroid hormones stimulated the growth of some bacterial species, specifically Lactobacillus spp., Bifidobacterium spp. Streptococcus spp. and E. coli. Several species, Lactobacillus spp., Propionibacterium spp., and Streptococcus spp., formed biofilms when incubated in native follicular fluids in vitro (18/24, 75%). We conclude that bacteria aspirated along with follicular fluid during IVF cycles demonstrate a persistent pattern of growth. This discovery is important since it can offer a new avenue for investigation in infertile couples.

Characterization of bacterial biofilms formed on urinary catheters

BACKGROUND

The formation of bacterial biofilms on urinary catheters is a leading cause of urinary tract infections in intensive care units. Cytobacteriological examination of urine from patients is often misleading, due to the formation of these biofilms. Therefore, characterizing these biofilms and identifying the bacterial species residing on the surface of catheters are of major importance.

METHODS

We studied the formation of biofilms on the inner surface of urinary catheters using microbiological culture techniques, with the direct contact of catheter pieces with blood agar. The bacterial species on the surface were characterized by scanning electron microscopy, and the kinetic profile of biofilm formation on a silicone substrate for an imipenem-resistant Acinetobacter baumannii bacterium was evaluated with a crystal violet staining assay.

RESULTS

The bacterial species that constituted these biofilms were identified as a variety of gram-negative bacilli, with a predominance of strains belonging to Pseudomonas aeruginosa. The other isolated strains belonged to A baumannii and Klebsiella ornithinolytica. Kinetic profiling of biofilm formation identified the transient behavior of A baumannii between its biofilm and planktonic state. This strain was highly resistant to all of the antibiotics tested except colistin. Scanning electron microscopy images showed that the identified isolated species formed a dense and interconnected network of cellular multilayers formed from either a single cell or from different species that were surrounded and enveloped by a protective matrix.

CONCLUSIONS

Microbiological analysis of the intraluminal surface of the catheter is required for true identification of the causative agents of catheter-associated urinary tract infections. This approach, combined with a routine cytobacteriological examination of urine, allows for the complete characterization of biofilm-associated species, and also may help prevent biofilm formation in such devices and help guide optimum antibiotic treatment.

Methods for studying Neisseria meningitidis biofilms

Neisseria meningitidisis an organism whose environmental niche is limited to the human host. It can frequently colonize the human nasopharynx and has the ability to cause severe systemic infections. These infections can be sporadic, endemic or occur in outbreaks associated with more virulent meningococcal strains. Studies have demonstrated that the meningococcus can form biofilms both in vivo and ex vivo. In this chapter, we discuss methods to establish biofilms in the laboratory for in-depth biochemical, genetic, or microscopic studies.

In vitro actinomycete biofilm development and inhibition by the polyene antibiotic, nystatin, on IUD copper surfaces

The presence of intrauterine contraceptive devices (IUDs) gives a solid surface for attachment and an ideal niche for biofilm to form and flourish. Pelvic actinomycosis is often associated with the use of IUDs. Treatment of IUD-associated pelvic actinomycosis requires the immediate removal of the IUD. Therefore, this article presents in vitro evidence to support the use of novel antibiotics in the treatment of actinomycete biofilms. Twenty one clinical actinomycetes isolates from endocervical swabs of IUD wearers were assessed for their biofilm forming ability. An in vitro biofilm model with three isolates, Streptomyces strain A4, Nocardia strain C15 and Nocardia strain C17 was subjected to treatment with nystatin. Inhibition of biofilm formation by nystatin was found to be concentration dependent, with MBIC50 values in the range 0.08-0.16 mg ml(-1). Furthermore, at a concentration of 0.16 mg ml(-1), nystatin inhibited the twitching motility of the isolates, providing evidence for a possible mechanism of biofilm inhibition.

Biofilm formation by Acinetobacter baumannii strains isolated from urinary tract infection and urinary catheters

Fifty Acinetobacter isolates were obtained from urinary tract infections and urinary catheter samples. Analytical profile index assays identified 47 isolates as Acinetobacter baumannii and three as Acinetobacter lwoffii. Six A. baumannii isolates (A1-A6) displayed hydrophobicity indices >70%. Twenty isolates exhibited lectin activity. Biofilm formation by these isolates was compared with those with low hydrophobicity index values (A45-A50). Biofilms on different surfaces were confirmed by light microscopy, epifluorescence microscopy and by obtaining scanning electron microscope images. Biofilm production was maximal at 30 °C, pH 7.0 in a medium with 5.0 g L(-1) NaCl, and its efficiency was reduced on urinary catheter surfaces at sub-minimum inhibitory concentration concentrations of colistin. Plasmid-mediated antibiotic resistance was observed in selected isolates of A. baumannii and experiments of conjugation and transformation showed the occurrence of gene transfer. Plasmid curing was used to examine the function of plasmids. Five plasmids of A. baumannii A3 were cured but no differences were observed between wild-type and plasmid-cured strains with respect to the biofilm formation capabilities. The prevalence of A. baumannii strains with biofilm mode of growth could explain their ability to persist in clinical environments and their role in device-related infections.

Effect of plant oils on Candida albicans

BACKGROUND/PURPOSE

Candida species, notably Candida albicans, is the major fungal pathogen in humans. It is a dimorphic fungus capable of causing superficial mucosal infections, as well as systemic infections, in immunocompromised individuals. The factors responsible for its pathogenesis are still not fully understood and increasing resistance to commonly used antifungal agents necessitates the search for new formulations.

METHODS

The inhibitory effect of 30 different plant oils on Candida albicans isolated from clinical samples was evaluated. The antifungal agent fluconazole was used as a positive control. Plant oils were tested at concentrations from 0.03% to 3% (v/v) to determine the minimum inhibitory concentration and minimum fungicidal concentration (MFC) using agar dilution and macro broth dilution assays.

RESULTS

Of the 30 plant oils tested, 18 were found to be effective and 12 were ineffective. Based on their MFCs, effective oils were placed into three categories: most effective, moderately effective and least effective. Eucalyptus and peppermint oils were most effective, with MFC values of 0.12% and 0.15% (v/v), respectively.

CONCLUSION

The significant antifungal activity of these oils suggests that they could serve as a source of compounds with therapeutic potential against Candida-related infections.

An intrauterine device as a possible cause of change in the microbial flora of the female genital system

AIM

An intrauterine device (IUD), used by millions of women worldwide, is one of the most efficient methods of contraception. The goal of our study was to compare a group of women using the IUD to a control group.

MATERIAL & METHODS

The survey included 236 women of fertile age from gynaecological practices in the area of Split and Dalmatia County, Croatia. The subjects were divided into two groups: IUD users and a control group (women not using any contraception methods). Sampling, transportation, sample processing in the laboratory and interpretation of results were conducted using standard microbiological procedures and methods.

RESULTS

Opportunistic bacteria were statistically more frequently isolated among IUD users (P < 0.001). The most frequently isolated bacteria in both groups were Escherichia coli and Ureaplasma urealyticum with significantly higher rates in IUD users (P < 0.001). Both colonization and infection had higher rates in IUD users (P < 0.001). There were no significant differences either in the frequency of bacteria isolation regarding different IUD types (P = 0.93), or in relation to duration of IUD use (P = 0.67).

CONCLUSIONS

Based on the data in our study IUD users have an increased chance of developing a cervical infection caused by the bacteria Escherichia coli and Ureaplasma urealyticum. Therefore, before IUD insertion women should be screened and treated for asymptomatic vaginal or cervical infections to prevent possible serious IUD-associated infections.

Biofilm formation on intrauterine devices in patients with recurrent vulvovaginal candidiasis

A biofilm is a complex community of surface-associated cells enclosed in a polymer matrix. They attach to solid surfaces and their formation can be affected by growth conditions and co-infection with other pathogens. The presence of biofilm may protect the microorganisms from host defenses, as well as significantly reduce their susceptibility to antifungal agents. Pathogenic microbes can form biofilms on the inert surfaces of implanted devices such as catheters, prosthetic cardiac valves and intrauterine devices (IUDs). The present study was carried out to analyze the presence of biofilm on the surface of intrauterine devices in patients with recurrent vulvovaginal candidiasis, and to determine the susceptibility profile of the isolated yeasts to amphotericin B and fluconazole. Candida albicans was recovered from the IUDs and it was found to be susceptible to the antifungal agents when tested under planktonic growing conditions. These findings indicate the presence of the biofilm on the surface of the IUD as an important risk factor for recurrent vulvovaginal candidiasis.

The prognosis of pregnancy conceived despite the presence of an intrauterine device (IUD)

OBJECTIVE

Intrauterine devices (IUDs) are used for contraception worldwide; however, the management of pregnancies with an IUD poses a clinical challenge. The purpose of this study was to determine the outcome of pregnancy in patients with an IUD.

STUDY DESIGN

A retrospective cohort study (December 1997-June 2007) was conducted. The cohort consisted of 12,297 pregnancies, of which 196 had an IUD. Only singleton pregnancies were included. Logistic regression analysis was used to adjust for potential confounders between the groups.

RESULTS

1) Pregnancies with an IUD were associated with a higher rate of late miscarriage, preterm delivery, vaginal bleeding, clinical chorioamnionitis, and placental abruption than those without an IUD; 2) among patients with available histologic examination of the placenta, the rate of histologic chorioamnionitis and/or funisitis was higher in patients with an IUD than in those without an IUD (54.2% vs. 14.7%; P<0.001). Similarly, among patients who underwent an amniocentesis, the prevalence of microbial invasion of the amniotic cavity (MIAC) was also higher in pregnant women with an IUD than in those without an IUD (45.9% vs. 8.8%; P<0.001); and 3) intra-amniotic infection caused by Candida species was more frequently present in pregnancies with an IUD than in those without an IUD (31.1% vs. 6.3%; P<0.001).

CONCLUSION

Pregnant women with an IUD are at a very high risk for adverse pregnancy outcomes. This finding can be attributed, at least in part, to the high prevalence of intra-amniotic infection and placental inflammatory lesions observed in pregnancies with an IUD.

In vitro Actinomyces israelii biofilm development on IUD copper surfaces

BACKGROUND

Female pelvic actinomycosis may involve fallopian tubes, ovaries, uterus and bladder. This condition is often associated with the use of intrauterine contraceptive devices (IUDs), vaginal pessaries and/or tampons. The predominant causative agent of human actinomycosis is Actinomyces israelii, which has been found on copper IUDs retrieved from patients.

STUDY DESIGN

In this work, a biofilm of A. israelii was developed in vitro on copper surfaces immersed in a simulated uterine fluid under anaerobic conditions. The biofilm was characterized using scanning electron microscopy (SEM), energy dispersive X-ray and atomic force microscopy.

RESULTS

The capacity of A. israelii to develop a biofilm over copper surfaces in synthetic media was demonstrated. SEM micrographies illustrate the exopolysaccharides production and bacterial distribution.

CONCLUSION

A. israelii was able to attach and grow in synthetic intrauterine media and to present on the copper surface is likely due to the production of biofilm.

Clinical and laboratory evidence for Neisseria meningitidis biofilms

Neisseria meningitidis is the etiologic agent of meningococcal meningitis. Carriage of the organism is approximately 10% while active disease occurs at a rate of 1:100,000. Recent publications demonstrate that N. meningitidis has the ability to form biofilms on glass, plastic or cultured human bronchial epithelial cells. Microcolony-like structures are also observed in histological sections from patients with active meningococcal disease. This review investigates the possible role of meningococcal biofilms in carriage and active disease, based on the laboratory and clinical aspects of the disease.

Biofilm formation by Candida albicans isolated from intrauterine devices

Our survey revealed that infected intrauterine devices (IUDs) recovered from patients suffering from reproductive tract infections (RTIs) were tainted with Candida biofilm composed of a single or multiple species. Scanning electron microscopy (SEM) analysis of C. albicans biofilm topography showed that it consists of a dense network of mono- or multilayer of cells embedded within the matrix of extracellular polymeric substances (EPS). Confocal scanning laser microscopy (CSLM) and atomic force microscopy (AFM) images depicted that C. albicans biofilms have a highly heterogeneous architecture composed of cellular and noncellular elements with EPS distributed in the cell-surface periphery or at cell-cell interface. Biochemical analysis showed that EPS produced by C. albicans biofilm contained significantly reduced total carbohydrate (40%), protein (5%) and enhanced amount of hexosamine (4%) in contrast to its planktonic counterparts. The in vitro activity of antifungal agents amphotericin B, nystatin, fluconazole and chlorhexidine against pre-formed C. albicans biofilm, assessed using XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay revealed increased resistance of these infectious biofilm (50% reduction in metabolic activity at a concentration of 8, 16, 64, 128 μg/ml respectively) in comparison to its planktonic form.