Secretory IgA and mucin-mediated biofilm formation by environmental strains of Escherichia coli: role of type 1 pili.

Recent studies suggest the importance of secretory IgA (SIgA) and mucin in the mediation of biofilm formation by commensal bacteria within the mammalian gut. Studies using a variety of strains of Escherichia coli have indicated that the interaction between E. coli and SIgA is dependent on the type 1 pilus. In this study, the importance of the pilus in SIgA-mediated biofilm formation by a laboratory strain (MG1655) and environmental (fecal) strains of E. coli was evaluated. Transient expression of the type 1 pilus by the laboratory strain of E. coli failed to facilitate SIgA-mediated biofilm formation, whereas constitutive expression of the type 1 pilus by the laboratory strain was sufficient. In contrast, transient expression of the type 1 pilus was sufficient to facilitate SIgA-mediated biofilm formation by environmental isolates. The "threshold" for mucin-mediated biofilm formation appeared to be lower than that for SIgA-mediated biofilm formation, perhaps reflecting disparate roles of mucin and SIgA in mediating biofilm formation in the gut. These studies also provide the first procedures for the growth of bacterial biofilms on live epithelial cells in vitro, an important development that may facilitate future studies on the effects of bacterial biofilms on epithelial cells.

Transplantation of the entire small bowel in inbred rats using cyclosporine.

Inbred strains of rats were used to analyze unidirectional host-versus-graft disease (transplant rejection) without graft-versus-host disease in small intestinal transplants and the immunosuppressive properties of cyclosporine (CsA). Forty-six Lewis rats received heterotopic transplants of the entire small bowel in four groups: Lewis-to-Lewis isografts, without CsA; Lewis-to-Lewis isografts, with CsA (15 mg/kg/day); (Lewis X ACI)F1-to-Lewis allografts, without CsA; (Lewis X ACI)F1-to-Lewis allografts, with CsA. Small bowel rejection was associated with gross morphological changes that preceded all other findings. A histologic scoring system assessed the degree of transplant rejection. A characteristic transient weight loss was seen in animals rejecting their bowels. Glucose absorption was impaired and polyethylene glycol absorption increased during rejection. Cyclosporine inhibited all of these changes in allografted rats. It is concluded that daily administration of cyclosporine is effective in preventing the morphologic and functional changes of acute transplant rejection in intestinal allografts and does not change these parameters in transplants that are not rejecting.

Sensitivity and specificity of rapid HIV testing of pregnant women in India.

OBJECTIVE: Efforts to prevent HIV transmission from mother to infants in settings like India may benefit from the availability of reliable methods for rapid and simple HIV screening. Data from India on the reliability of rapid HIV test kits are limited and there are no data on the use of rapid HIV tests for screening of pregnant women. METHODS: Pregnant women attending an antenatal clinic and delivery room in Pune agreed to participate in an evaluation of five rapid HIV tests, including (a) a saliva brush test (Oraquick HIV-1/2, Orasure Technologies Inc.), (b) a rapid plasma test (Oraquick HIV-1/2) and (c) three rapid finger prick tests (Oraquick HIV-1/2; HIV-1/2 Determine, Abbott; NEVA HIV-1/2 Cadila). Results of the rapid tests were compared with three commercial plasma enzyme immunoassay (EIA) tests (Innotest HIV AB EIA, Lab systems/ELISCAN HIV AB EIA, UBI HIV Ab EIA). RESULTS: Between September 2000 and October 1, 2001, 1258 pregnant women were screened for HIV using these rapid tests. Forty-four (3.49%) of the specimens were HIV-antibody-positive by at least two plasma EIA tests. All of the rapid HIV tests demonstrated excellent specificity (96-100%). The sensitivity of the rapid tests ranged from 75-94%. The combined sensitivity and specificity of a two-step algorithm for rapid HIV testing was excellent for a number of combinations of the five rapid finger stick tests. CONCLUSION: In this relatively low HIV prevalence population of pregnant women in India, the sensitivity of the rapid HIV tests varied, when compared to a dual EIA algorithm. In general, the specificity of all the rapid tests was excellent, with very few false positive HIV tests. Based upon these data, two different rapid HIV tests for screening pregnant women in India would be highly sensitive, with excellent specificity to reliably prevent inappropriate use of antiretroviral therapy for prevention of vertical HIV transmission.

Phase I safety & preliminary acceptability of nonoxynol-9 vaginal pessary as a vaginal microbicide in low risk women in Pune, India.

BACKGROUND & OBJECTIVES: Though nonoxynol-9 (N-9) is available in India as a spermicidal pessary, data on its safety as a potential microbicide among Indian women are not available. Nonoxynol-9 containing compounds have shown anti-HIV activity in in vitro studies and protection against cervical infections. Nonoxynol-9 is being extensively evaluated as a vaginal microbicide world-wide. We assessed the safety and preliminary acceptability of nonoxynol-9 pessary as a vaginal microbicide in women at low risk for human immunodeficiency virus (HIV) infection and sexually transmitted diseases (STDs). METHODS: Twenty three HIV seronegative women enrolled in the study were given Today pessarys containing 5 per cent of nonoxynol-9 for vaginal use at bedtime for 14 days. Colposcopy was done at enrollment and on day 14 and speculum examination on day 7 to assess the local toxicity. RESULTS: Most of the women (16/23, 69.6%) did not experience any symptoms of genital irritation. The remaining 7 (30.4%, 95% CI 11.6-49.2) women reported 11 episodes of mild irritative symptoms of short duration. On clinical examination, three adverse events were reported of which one could have been product related. Eight (34.8%) women showed willingness to use the product for protection against HIV transmission if it was approved. INTERPRETATION & CONCLUSION: Nonoxynol-9 vaginal pessary was found to be safe and acceptable in once daily dose in low risk women after consecutive use for 14 days. Willingness for future use, if found safe and effective for HIV prevention was shown by 8 (34.8%) women.

Prospective evaluation of a Dacron cuffed hemodialysis catheter for prolonged use.

Double lumen subclavian venous hemodialysis catheters are in wide use in the United States to provide temporary vascular access. The disadvantages of these catheters include a high infection rate and short use-life (2 to 3 weeks). We evaluated a felt cuffed tunnelled jugular venous hemodialysis catheter (PermCath) to determine its ability to overcome these shortcomings and compared it with standard noncuffed double lumen dialysis catheters. Eighty PermCaths were inserted during this prospective study in patients needing temporary vascular access in excess of 1 month. Median use-life of these catheters was 8 weeks with a use range of 3 weeks to 5.4 months. Only four functioning catheters failed before elective removal. Despite the prolonged use-life there was only one episode of catheter mediated bacteremia. Seven catheters (9%) failed to function immediately after insertion. These failures were caused by catheter kinking in the region of the felt cuff. Thrombosis of the catheter lumen was the most frequent complication (137 episodes) but resolved in over 95% of the instances with urokinase instillation. Exit site infections (23 instances) were successfully treated conservatively. We conclude that the PermCath (Quinton Instrument Co, Seattle) is a safe and reliable new device with a low complication rate and a longer use-life than standard subclavian dialysis catheters. This longer use-life allows more time for maturation of primary arteriovenous (AV) fistulas and Tenckhoff peritoneal dialysis catheters, and provides time for the healing of infected vascular access grafts. Its primary disadvantage is the need for surgical insertion.

Phase 1 trial of the topical microbicide BufferGel: safety results from four international sites.

AIM: To evaluate the safety of BufferGel (ReProtect LLC, Baltimore, MD), a spermicidal microbicide that acidifies semen and maintains the protective acidity of the vagina, in a high-dose tolerance trial. METHODS: HIV/STD negative, sexually abstinent, and sexually active women in India, Thailand, Malawi, and Zimbabwe were asked to insert one applicator ( approximately 5 ml) of BufferGel vaginally twice per day for 14 days. Sexually active women agreed to have sex (while using BufferGel and nonlubricated condoms) at least twice per week. RESULTS: In total, 98 women (30 sexually abstinent and 68 sexually active) were enrolled. Overall compliance with product use was 93%. Epithelial abnormalities detected by pelvic examination or colposcopy were uncommon (8 cases in 271 examinations). Irritation was reported by approximately one quarter of the women (0.58 events per woman-week) but was generally mild and of short duration. The prevalence of bacterial vaginosis (BV) fell significantly, from 30% at enrollment to 6% at one week, and 7% at two weeks of BufferGel use. Thirty-two women acquired microscopically detectable yeast during BufferGel exposure, but only 3 developed symptomatic vaginitis. CONCLUSION: BufferGel appears to be safe and well tolerated by the cervicovaginal epithelium. Its effect on BV and yeasts merits further study.