Formation and role of glycine betaine in the moderate halophile Vibrio costicola

The moderate halophile Vibrio costicola, growing on a chemically-defined medium, transformed choline into glycine betaine (betaine) by the membrane-bound enzyme choline dehydrogenase and the cytoplasmic enzyme betainal (betaine aldehyde) dehydrogenase. Choline dehydrogenase was strongly induced and betainal dehydrogenase less strongly induced by choline. The formation of these enzymes was also regulated by the NaCl concentration of the growth medium, increasing with increasing NaCl concentrations. Intracellular betaine concentrations also increased with increasing choline and NaCl concentrations in the medium. This increase was almost completely blocked by chloramphenicol, which does not block the increase in salt-tolerant active transport on transfer from a low to a high salt concentration.Choline dehydrogenase was inhibited by chloride salts of Na⁺, K⁺, and NH _inf4 ^su+ , the inhibition being due to the Cl^- ions. Betainal dehydrogenase was stimulated by 0.5 M salts and could function in up to 2.0 M salts.Cells grew as well in the presence as in the absence of choline in 0.5 M and 1.0 M NaCl, but formed no intracellular betaine. Choline stimulated growth in 2.0 M NaCl and was essential for growth in 3.0 M NaCl. Thus, while betaine is important for some of the adaptations to high salt concentration by V. costicola, it by no means accounts for all of them.Abbreviations CDMM chemically-defined minimal medium - PPT proteose-peptone tryptone medium - SDS sodium dodecyl sulfate Deceased, 1987     

Sensitivity to antimicrobial agents of some mercury-sensitive and mercury-resistant strains of Gram-negative bacteria

The sensitivity and resistance of some Gram-negative mercury (Hg²⁺)-sensitive and-resistant strains to chemotherapeutic agents and to disinfectants and preservatives are described.Escherichia coli andPseudomonas aeruginosa strains harboring plasmid pUB 1351 [pUB 367:Tn 501] andE. coli bearing R100-1 were resistant to inorganic mercury and to various antibiotics, but were not more resistant to organic mercury and other preservatives and disinfectants than plasmidless strains.     

Response of RP1+ and RP1− strains ofEscherichia coli to antibacterial agents and transfer of resistance toPseudomonas aeruginosa

The sensitivity of strains ofEscherichia coli, with and without the RP1 R-factor, to antibiotics and other antibacterial agents has been studied. RP1⁺ strains ofE. coli were resistant to kanamycin, carbenicillin, and tetracycline, resistance to the first two antibiotics being produced by destruction of the drugs. This resistance could be transferred to two strains ofPseudomonas aeruginosa. The parent strain ofE. coli UB 1005, its two mutant strains (DC2 and DC3), and two of the strains with the RP1 R-factor showed a similar order of sensitivity to phenylmercuric nitrate, chlorhexidine, thiomersal, and mercuric chloride.E. coli strains DC2 and DC2 (RP1⁺) were the most sensitive to benzalkonium chloride and cetrimide. RP1⁺ strains were more resistant than RP1⁻ strains to lysozyme-ethylenediaminetetraacetic acid, but treatment of the former strains with acriflavine rendered the cells more sensitive to the lytic system. There was no evidence thatP. aeruginosa (RP1⁺) strains possessed increased resistance to polymyxin or to disinfectants, although they became somewhat less sensitive to lysozyme-ethylenediaminetetraacetic acid.     

Increased incidence of pertussis and parapertussis in HIV-1-positive adolescents vaccinated previously with whole-cell pertussis vaccine

We investigated 296 adolescents (11–18 years), who had been immunized previously with the three doses of DPT vaccines. 48 were diagnosed positive for HIV-1. Nasopharyngeal swabs were obtained from 296 adolescents who presented with persistent cough and nasopharyngeal secretions. Nasopharyngeal swabs (calcium alginate) specimens were collected by passing the swabs through the nares into the posterior nasopharynx and rotating the swabs for a few seconds. The swabs were plated for culture of Bordetella organisms in charcoal cephalexin blood agar (CCBA). The CCBA plates were incubated for 2–6 days at 35 °C in a humid aerobic atmosphere. The suspected, shiny (mercury-like) colonies were tested by slide agglutination with antisera to B. pertussis and B. parapertussis, and urease, oxidase activities were performed. Results indicate that out of 48 HIV-1-positive adolescents, 18 had positive cultures for Bordetella organisms (14, Bordetella pertussis, and 4, Bordetella parapertussis). Of 248 HIV-1-negative subjects, 3 had Bordetella organisms (2, Bordetella pertussis, 1, Bordetella bronchiseptica). One of the subjects, a boy, aged 14 years, with Bordetella bronchiseptica had a dog as pet, which was found to be infected. The results indicate that adolescents with HIV-1 infection, despite being vaccinated against pertussis have a higher rate of infection when exposed to pertussis bacteria than HIV-1-negative adolescents. This revised version was published online in August 2006 with corrections to the Cover Date.     

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

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.     

Not all are lost: interrupted laboratory monitoring, early death, and loss to follow-up (LTFU) in a large South African treatment program

Background

Many HIV treatment programs in resource-limited settings are plagued by high rates of loss to follow-up (LTFU). Most studies have not distinguished between those who briefly interrupt, but return to care, and those more chronically lost to follow-up.

Methods

We conducted a retrospective cohort study of 11,397 adults initiating antiretroviral therapy (ART) in 71 Southern African Catholic Bishops Conference/Catholic Relief Services HIV treatment clinics between January 2004 and December 2008. We distinguished among patients with early death, within the first 7 months on ART; patients with interruptions in laboratory monitoring (ILM), defined as missing visits in the first 7 months on ART, but returning to care by 12 months; and those LTFU, defined as missing all follow-up visits in the first 12 months on ART. We used multilevel logistic regression models to determine patient and clinic-level characteristics associated with these outcomes.

Results

In the first year on ART, 60% of patients remained in care, 30% missed laboratory visits, and 10% suffered early death. Of the 3,194 patients who missed laboratory visits, 40% had ILM, resuming care by 12 months. After 12 months on ART, patients with ILM had a 30% increase in detectable viremia compared to those who remained in care. Risk of LTFU decreased with increasing enrollment year, and was lowest for patients who enrolled in 2008 compared to 2004 [OR 0.49, 95%CI 0.39–0.62].

Conclusions

In a large community-based cohort in South Africa, nearly 30% of patients miss follow-up visits for CD4 monitoring in the first year after starting ART. Of those, 40% have ILM but return to clinic with worse virologic outcomes than those who remain in care. The risk of chronic LTFU decreased with enrollment year. As ART availability increases, interruptions in care may become more common, and should be accounted for in addressing program LTFU.     

Intramuscular Injection of AAV8 in Mice and Macaques Is Associated with Substantial Hepatic Targeting and Transgene Expression

Intramuscular (IM) administration of adeno-associated viral (AAV) vectors has entered the early stages of clinical development with some success, including the first approved gene therapy product in the West called Glybera. In preparation for broader clinical development of IM AAV vector gene therapy, we conducted detailed pre-clinical studies in mice and macaques evaluating aspects of delivery that could affect performance. We found that following IM administration of AAV8 vectors in mice, a portion of the vector reached the liver and hepatic gene expression contributed significantly to total expression of secreted transgenes. The contribution from liver could be controlled by altering injection volume and by the use of traditional (promoter) and non-traditional (tissue-specific microRNA target sites) expression control elements. Hepatic distribution of vector following IM injection was also noted in rhesus macaques. These pre-clinical data on AAV delivery should inform safe and efficient development of future AAV products.     

Augmentation of antimicrobial metronidazole therapy of bacterial vaginosis with oral probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14: randomized, double-blind, placebo controlled trial

This study enrolled 125 premenopausal women diagnosed with bacterial vaginosis (BV) by presence of vaginal irritation, discharge and 'fishy' odor, and Nugent criteria and detection of sialidase enzyme. The subjects were treated with oral metronidazole (500 mg) twice daily from days 1 to 7, and randomized to receive oral Lactobacillus rhamnosus GR-1 (1 x 10(9)) and Lactobacillus reuteri RC-14 (1 x 10(9)) or placebo twice daily from days 1 to 30. Primary outcome was cure of BV as determined by normal Nugent score, negative sialidase test and no symptoms or signs of BV at day 30. A total of 106 subjects returned for 30-day follow-up, of which 88% were cured in the antibiotic/probiotic group compared to 40% in the antibiotic/placebo group (p<0.001). Of the remaining subjects, 30% subjects in the placebo group and none in the probiotic group had BV, while 30% in the placebo and 12% in the probiotic group fell into the intermediate category based upon Nugent score, sialidase result and clinical findings. High counts of Lactobacillus sp. (>10(5) CFU/ml) were recovered from the vagina of 96% probiotic-treated subjects compared to 53% controls at day 30. In summary, this study showed efficacious use of lactobacilli and antibiotic in the eradication of BV in black African women.     

The use of starter cultures to produce ‘Pito’, a Nigerian fermented alcoholic beverage

Pito a traditional Nigerian alcoholic beverage was brewed in the laboratory with pure cultures of Lactobacillus plantarum in combination with Saccharomyces cerevisiae and Pediococcus halophilus in combination with Candida tropicalis isolated from a local brew. The pH, colour, titrable acidity, alcohol content, specific gravity, taste and flavour of Pito produced by this method compared favourably with that produced by the traditional method. The method achieved a reduced fermentation time and an improved production process. It is recommended that Pito be produced with Lactobacillus plantarum in combination with Saccharomyces cerevisiae.