Showing papers by "Gregor Reid published in 2006"

Probiotics to prevent urinary tract infections: the rationale and evidence.

Abstract: For over 30 years, urologists have recognized in females, that urinary pathogens almost always infect the host through ascension from the rectum, vagina to the urethra and bladder. Likewise, the Lactobacillus organisms that predominate in the vagina of healthy women, spread from the rectum and perineum and form a barrier in the vagina to bladder entry by uropathogens. The concept of artificially boosting the lactobacilli numbers through probiotic instillation has long been conceived, but only in recent years shown to be possible. Not all lactobacilli are effective, and to date clinical efficacy only exists for Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri B-54 and RC-14. These strains are only commercially available in Austria, and therefore for most urologists, while some probiotic organisms may reduce the recurrences of bladder cancer or oxaluria, no probiotics can be recommended widely to prevent UTI at present.

G-CSF-mediated inhibition of JNK is a key mechanism for Lactobacillus rhamnosus-induced suppression of TNF production in macrophages.

Abstract: Summary Lactobacillus rhamnosus is a human commensal with known immunomodulatory properties. To date the mechanism of these immunomodulatory effects is not well understood. To unravel the immunomodulatory signalling mechanism, we investigated the effects of two strains of L. rhamnosus, L. rhamnosus GG and GR-1, in modulating production of tumour necrosis factor-α (TNF) in human monocytic cell line THP-1 and mouse macrophages. Live L. rhamnosus GG and GR-1 or their spent culture supernatant induced minuscule amounts of TNF production but large quantities of granulocyte-colony stimulating factor (G-CSF) in macrophages compared with those induced by pathogenic Escherichia coli GR-12 and Enterococcus faecalis. By using neutralizing antibodies and G-CSF receptor knockout mice, we demonstrated that G-CSF secreted from L. rhamnosus GG- and GR-1-exposed macrophages suppressed TNF production induced by E. coli- or lipopolysaccharide-activated macrophages through a paracrine route. The suppression of TNF production by G-CSF was mediated through activation of STAT3 and subsequent inhibition of c-Jun-N-terminal kinases (JNKs). The inhibition of JNK activation required STAT3α-mediated de novo protein synthesis. This demonstrates a novel role of G-CSF in L. rhamnosus-triggered anti-inflammatory effects and its mechanism in the suppression of TNF production in macrophages.

Lactobacillus vaginal microbiota of women attending a reproductive health care service in Benin city, Nigeria.

Abstract: The objective of this study was to determine whether Lactobacillus species found in African women differ substantially to those of white decent described in previous studies. The vaginal microbiota play an important role in female health and when the naturally dominant lactobacilli are displaced resulting in bacterial vaginosis (BV) the host is more at risk of acquiring sexually transmitted diseases including HIV. Vaginal samples were collected from 241 healthy premenopausal Nigerian women which were then Gram-stained for Nugent scoring. Microbial DNA was extracted amplified using polymerase chain reaction (PCR) and Lactobacillus primers and processed by denaturing gradient gel electrophoresis (DGGE). Lactobacillus species were identified by DNA sequencing and BLAST algorithm. Of the samples 207 (85.8%) had PCR products for lactobacilli whereas 34 (14.2%) showed absence of lactobacilli which correlated to the BV Nugent scores. On sequencing of amplicons 149 subjects (72%) had sequence homologies to lactobacilli. Most women (64%) were colonized by L. iners as the predominant strain similar to previous findings in Canadian and Swedish women. L. gasseri was found in 7.3% samples followed by L. plantarum L. suntoryeus L. crispatus L. rhamnosus and other species. The findings indicate that even with geographic racial and other differences the predominant vaginal Lactobacillus species is similar to species in women from Northern countries. (authors)

Selecting, testing and understanding probiotic microorganisms

Abstract: The interest in probiotics and the modulation of microbiota for restoring and maintaining health continues to gain momentum. Research is fueled by a need to develop alternatives to antibiotics and drugs that have severe side effects. It is recognised that bacteria play a major role in human and animal health, and how scientific advances help to explain how and when probiotics work. This minireview provides an update on critical studies, particularly since 2002, that are helping to explain the mechanisms of action of probiotic organisms.

Inhibition of expression of a staphylococcal superantigen-like protein by a soluble factor from Lactobacillus reuteri.

Abstract: Lactobacillus reuteri RC-14 has previously been shown to inhibit Staphylococcus aureus infection in a rat surgical-implant model. To investigate the basis for this, communication events between the two bacterial species were examined. L. reuteri RC-14 and Staph. aureus Newman were grown in a co-culture apparatus that physically separates the two species, while allowing the passage of soluble compounds. Using two-dimensional gel electrophoresis (2D-E), protein expression changes in Staph. aureus were analysed in response to co-culture with medium alone, L. reuteri RC-14, and a Lactobacillus strain that did not inhibit Staph. aureus infection in the rat model. It was observed that one protein in particular, identified as staphylococcal superantigen-like protein 11 (SSL11), showed a dramatic decrease in expression in response to growth with L. reuteri RC-14. Genetic reporters that placed both gfp and lux under the transcriptional control of the SSL11 promoter confirmed the 2D-E results. Interestingly, using similar reporter gene experiments, it was observed that the Staph. aureus P3 promoter from the staphylococcal accessory gene regulator (agr) locus also showed a decrease in expression in response to growth in the presence of L. reuteri RC-14. It was further demonstrated that L. reuteri RC-14 supernatant contained small unidentified molecules that were able to repress the SSL11 and P3 promoters, but the repression of SSL11 occurred independently of the agr system. These results suggest that L. reuteri RC-14 has the potential to alter the virulence of Staph. aureus via secretion of cell–cell signalling molecules.

Megaplasmids encode differing combinations of lantibiotics in Streptococcus salivarius.

Abstract: Streptococcus salivarius strains commonly produce bacteriocins as putative anticompetitor or signalling molecules. Here we report that bacteriocin production by the oral probiotic strain S. salivarius K12 is encoded by a large (ca. 190 kb) plasmid. Oral cavity transmission of the plasmid from strain K12 to a plasmid-negative variant of this bacterium was demonstrated in two subjects. Tests of additional S. salivarius strains showed large (up to ca. 220 kb) plasmids present in bacteriocin-producing isolates. Various combinations (up to 3 per plasmid) of loci encoding the known streptococcal lantibiotics salivaricin A, salivaricin B, streptin and SA-FF22 were localised to these plasmids. Since all bacteriocin-producing strains of S. salivarius tested to date appear to harbour plasmids, it appears that they may function as mobile repositories for bacteriocin loci, especially those of the lantibiotic class.

In-vitro activity of triclosan-eluting ureteral stents against common bacterial uropathogens.

Abstract: Background and Purpose: Ureteral stents are commonly used in urology today, but the biofilms that form on them within hours of placement may harbor bacteria that can result in infection or encrusta...

Probiotics to prevent the need for, and augment the use of, antibiotics.

Abstract: Although humans and microbes are inseparable, our knowledge and understanding of the majority of microbes that help keep us alive and well is in desperate need of further investigation. Of the organisms that influence humans before birth and inhabit various niches from birth to old age, we know little about their identity, origin, metabolic properties, attributes and mechanisms of interactions with the host and surrounding microbes. The use of probiotics ("live microorganisms which when administered in adequate amounts confer a health benefit on the host") has re-emerged as a means to restore and boost the beneficial microbes in our bodies. The timing of resurgent interest in this ancient field coincides with the need to augment or replace antibiotics whose side effects are unwelcome and whose efficacy is diminishing due to drug resistance. Evidence that probiotic strains can act as adjuncts to antibiotic therapy by reducing adverse effects, improving antibiotic function and enhancing mucosal immunity is mounting. It is to our discredit that basic research on microbial ecology has been stalled in Canada for the past 20 years. If supported, research into indigenous and probiotic microbes will form an important part of future research that sheds light on health, disease and a basic understanding of life itself. In some cases, probiotics will be the difference between a good quality of life and a bad one, or perhaps even life over death. Improvements in clinical studies, manufacturing and regulatory standards must coincide with this progress to ensure that physicians and consumers have reliable, proven products for safe and efficacious use.

Knowledge of probiotics by Nigerian clinicians

Abstract: A reasonable proportion of clinicians in the Northern hemisphere may be familiar with the use of probiotics and some have clearly been involved in probiotic research for some time. However, we hypothesized that medical practitioners in Nigeria are yet to grasp the concept of using probiotics either as health promoting foods or as biotherapeutic agents for the treatment of diarrhea or urogenital infections. In order to determine the extent of awareness on the use of probiotics among qualified medical practitioners in Benin City, Nigeria, a survey was carried out. The survey involved the use of close-ended and open-ended structured questionnaires and 125 randomly sampled medical practitioners. The survey asked about current knowledge on the subject, and provided information to gauge the potential receptivity to using or recommending probiotics in patient care. 62 medical practitioners responded. The results showed that 95.2% of the respondents were not familiar with the term probiotics, and all (100%) indicated that they would like more information on the subject. Up to 75% of the participants raised some concerns bordering on the safety and receptivity of probiotics products among the prospective users. Many respondents (66.1%) stated that they would need positive clinical trial data to be convinced on the efficacy of probiotics before prescribing or recommending it to their patients. To access such data, 64.5% preferred medical textbooks, while only 27.4% indicated peer- reviewed medical journals, perhaps a reflection of the fact that many practitioners in Nigeria are busy and do not have easy access to such journals. Nevertheless, 64.5% were in favor of probiotics and stated they would approve it for health maintenance. 37% stated a preference for an oral capsule and 45.1% yogurts. The findings revealed that in spite of the concerns expressed, many clinicians are willing to participate in clinical trials on probiotics and are extremely interested to learn more about scientifically and clinically proven products.

Rat PSP94 inhibits the growth and viability of the rat adenocarcinoma cell line PAIII in vitro.

Abstract: Previous studies have shown that human PSP94 can inhibit the growth of prostate cancer cells both in vitro and in vivo. To further validate this potential and investigate the protein within a homologous setting, we examined the effects of rat PSP94 on the growth of the rat prostate adenocarcinoma cell line PAIII in vitro. To generate rat PSP94, we used both a plasmid-based expression system and a recombinant rat PSP molecule. Rat PSP was shown to inhibit the growth and survival of PAIII cells in a dose-dependent manner with > 90 percent reductions in both observed. TUNEL and Annexin-V assays confirmed PAIII cell death to be via apoptosis.

Association between absence of vaginal lactobacilli PCR products and nugent scores interpreted as bacterial vaginosis

Abstract: Context : The most common cause of abnormal vaginal discharge in women of childbearing age is bacterial vaginosis (BV). This condition predisposes women to increased susceptibility to sexually transmitted diseases, including human immunodeficiency virus (HIV) infections and preterm birth. The diagnostic methods commonly adopted in the evaluation of patient samples for BV are Amsel criteria and Nugent score, the latter requiring microscopy and expert interpretation. The use of polymerase chain reaction (PCR) with group specific lactobacillus primers, in combination with Nugent criteria has not been widely used in developing countries such as Nigeria. Objective : The aim of the present study was to examine the relationship between vaginal Lactobacilli using PCR with group specific lactobacillus primers and Nugent Score criteria for bacterial vaginosis. Study Design, Setting, Subjects, and Methods : We evaluated 241 vaginal samples from apparently healthy premenopausal women in Benin City for the presence of Lactobacilli with group specific primers in a polymerase chain reaction master cycler and bacterial vaginosis using the Nugent score criteria. Results : Of the 241 vaginal samples that were Gram stained for Nugent rating, 84 (34.8%) had Normal rating (0-3), 123 (51%) had Intermediate score (4-6), while 34 (14.2%) had Bacterial vaginosis, with Nugent score (7-10). There was a positive association between absence of Lactobacilli PCR product and Nugent scores interpreted as BV (85.8% vs. 14.2%. x 2 = 4.12, P=0.05). Conclusion : The study has demonstrated a strong relationship between bacterial vaginosis and absence or depletion of vaginal lactobacilli using molecular techniques. Keywords : lactobacilli, bacterial vaginosis, nugent score, polymerase chain reaction Tropical Journal of Obstetrics and Gynaecology Vol. 22(2) 2005: 103-107

Assessment of Lactobacillus species colonizing the vagina of apparently healthy Nigerian women, using PCR-DGGE and 16S rRNA gene sequencing

Abstract: The identity of lactobacilli colonizing Africa-American women, have previously been based on culture-dependent methods. This led to some misleading speculations that black women lack lactobacilli in their vagina and are therefore highly susceptible to Bacterial vaginosis and STDs including HIV. In this study we used culture-independent procedures.About 241 vaginal swabs were obtained from ‘apparently’ healthy premenopausal women, between 18 and 48 years. Samples were Gram stained for the Nugent score evaluation. DNA was extracted from the bacteria on the vaginal swabs and amplified using polymerase chain reaction (PCR), with Lactobacillus primers. Samples with PCR products were separated with denaturing gradient gel electrophoresis (DGGE) and cut bands were re-amplified with Lactobacillus primers without the GC clamp. The re-amplified product was purified and sequenced with ABI PRISM Big-Dye Terminator. The sequence was identified with BLAST algorithm having the highest Gene Bank Accession number. Out of the 241 vaginal swab samples, 207 (85.8%) had PCR products, indicating the presence of lactobacilli, while 34 (14.2%) showed absence of lactobacilli and the Nugent scores were synonymous to either intermediate bacterial vaginosis or bacterial vaginosis (BV). Out of the 207 samples that had PCR product for Lactobacillus, 149 (72%) had sequence results as revealed by the BLAST algorithm. Most of the women (64%) were colonized by Lactobacillus iners as the predominant strain. Lactobacillus gasseri had 7.3%, followed by L. plantarum and L suntoryeus (6.0%) each. Others were colonized by Lactobacillus crispatus (3.0%), Lactobacillus rhamnosus (2.7%), Lactobacillus vaginalis (2.7%), Lactobacillus rennanqilfy (2.7%), followed by Lactobacillus fermentum (1.3%), Lactobacillus helveticus (1.3%), Lactobacillus johnsonii (1.3%) and Lactobacillus salivarus (1.3%). To our knowledge, this is the first report of Lactobacillus iners being the predominant species colonizing the vagina of the Nigerian women examined. This finding is in line with those from a recent study conducted among Canadian and Swedish women.

Prevention and treatment of urogenital infections and complications: lactobacilli's multi-pronged effects

Abstract: The association between depletion of vaginal lactobacilli and increased risk of various urogenital infections and complications such as preterm labor, has been known for some time. Restoration of depleted lactobacilli by administration of probiotic strains has been demonstrated in humans using Lactobacillus rhamnosus GR-1 and L. reuter i RC-14. These organisms also augment antibiotic efficacy, lessen the side effects of these drugs, and alleviate diarrhea in AIDS patients. The mechanisms appear to be multi-factorial, and include production of: (i) anti-microbial factors such as lactic acid, bacteriocins, hydrogen peroxide, (ii) biosurfactants or other components that affect pathogen colonization and biofilm formation, (iii) signalling compounds that influence pathogen virulence expression, and (iv) signalling compounds that modulate immunity. Recombinant strains have been produced that inhibit or kill HIV, offering hope for microbicide applications that can be self-used by women. As more information becomes available about the ‘normal’ versus ‘disease prone’ vaginal microbiota and strains that confer the most benefits, current and new probiotic remedies will potentially provide improved restorative and therapeutic options to lower the one billion urogenital infections currently afflicting women around the world. Key words: probiotics, lactobacillus, urogenital infections, mechanisms

Use of genetically modified microbes for human health

Abstract: Sir , The publication by Ott et al. (1) restates the important, and topical, use of microbes in treating disease, in this case lymphoid immunodeficiencies. However, not everyone agrees that recombinant bacteria should be used in humans, and one particular submission to this journal called for a ban of such uses, a viewpoint that we wish to now strongly challenge (2).