Gregory Maitha

Prophylaxis of gonococcal and chlamydial ophthalmia neonatorum. A comparison of silver nitrate and tetracycline

Abstract We evaluated the use of silver nitrate drops and tetracycline ointment for the prophylaxis of ophthalmia neonatorum in a controlled trial involving 2732 newborns in Nairobi, Kenya. The overall rates of prevalence of intrapartum maternal gonococcal and chlamydial infection were 6.4 and 8.9 percent, respectively. After prophylaxis with silver nitrate, the incidence rates of gonococcal, chlamydial, and nongonococcal, nonchlamydial ophthalmia neonatorum were 0.4, 0.7, and 6.2 percent, respectively, whereas after prophylaxis with tetracycline, the rates were 0.1, 0.5, and 4.5 percent. The attack rates of gonococcal ophthalmia neonatorum in newborns exposed to Neisseria gonorrhoeae at birth were 7.0 percent in those receiving silver nitrate and 3.0 percent in those receiving tetracycline (95 percent confidence interval for the difference in rates, -3.4 to 11.4 percent). As compared with historical controls, the incidence of gonococcal ophthalmia neonatorum decreased 83 percent among infants treated wit...

Impact of maternal HIV infection on obstetrical and early neonatal outcome

In a case-control study of 177 HIV-seropositive and 326 seronegative women and their newborns in Nairobi, Kenya, maternal HIV infection at term was independently associated with travel to other African countries [odds ratio (OR) 4.9, P less than 0.0001], history of a blood transfusion since 1980 (OR 3.5, P = 0.01), history of more than one sexual partner in the previous 5 years (OR 1.8, P = 0.02) and unmarried status (OR 1.8, P = 0.02). Neonates of HIV-positive and HIV-negative women differed little with respect to occurrence of congenital malformations, stillbirths, in-hospital mortality, sex, APGAR score, or gestational age. However, the mean birth weight of singleton neonates of HIV-positive women was significantly lower than that of controls (3090 versus 3220 g, P = 0.005), and birth weight was less than 2500 g in 9% of cases and 3% of controls (OR 3.0, P = 0.007). Among neonates of HIV-seropositive women, birth weight was less than 2500 g in 17% if mothers were symptomatic and 6% if mothers were asymptomatic (OR 3.4, P = 0.08).

Chlamydia trachomatis from individuals in a sexually transmitted disease core group exhibit frequent sequence variation in the major outer membrane protein (omp1) gene.

60 cervical Chlamydia trachomatis infections identified by antigen detection from 51 prostitute women in Nairobi, Kenya were evaluated for sequence polymorphism in the major outer membrane protein (omp1) gene. DNA from clinical specimens was amplified by the polymerase chain reaction and cycle sequenced through variable domains (VD) 1, 2, and 4.37 (63%) samples had variant VD sequences, 19 (32%) samples had prototype VD sequences, and 4 (6%) samples had prototype VD sequences, and 4 (6%) samples contained omp1 sequences from two or more C. trachomatis strains. Among the 37 variant strains, 18 had two or fewer nucleotide substitutions in one or two VDs and represented point mutational drift variants. 19 strains had a larger number of nucleotide changes and displayed mosaic omp1 sequences that may have been generated by omp1 VD recombination. We conclude that the prevalence of C. trachomatis omp1 DNA polymorphism is substantial among prostitute women in Nairobi, Kenya and that this is the likely result of immune selection pressure.

EPIDEMIOLOGY OF OPHTHALMIA NEONATORUM IN KENYA

In a Nairobi hospital where ocular prophylaxis against ophthalmia neonatorum has been discontinued, 1,019 women were screened for Neisseria gonorrhoeae and Chlamydia trachomatis during labour and 7 and 28 days postpartum. The prevalence of gonococcal infection was 7% and that of chlamydial was 29%. 52.4% of gonococcal isolates produced penicillinase. The incidence of ophthalmia neonatorum was 23.2 per 100 live births, and incidences of gonococcal and chlamydial ophthalmia were 3.6 and 8.1 per 100 live births, respectively. Of 181 cases of neonatal conjunctivitis, 31% were caused by C trachomatis, 12% by N gonorrhoeae, and 3% by both. In 67 babies exposed to maternal gonococcal infection and 201 exposed to maternal chlamydial infection, rates of transmission to the eye were 42% and 31%, respectively, and to the throat were 7% and 2%. Gonococcal transmission rate was higher in mothers with concomitant chlamydial infection (68%; p = 0.01). Postpartum endometritis was associated with ophthalmia neonatorum (p less than 0.001). Ocular prophylaxis at birth for gonococcal ophthalmia should be reintroduced.

Comparison of media for the primary isolation of Haemophilus ducreyi

The rates of isolation of Haemophilus ducreyi from patients with presumed chancroid has been low, and improved cultural techniques are required. We determined the isloation rates of H. ducreyi from 38 patients with clinical chanceroid and compared gonococcal agar supplemented with bovine hemoglobin to Mueller-Hinton agar supplemented with chocolated horse blood, each with and without 5% fetal calf serum. The rate of isolation and the qualitative and quantitative growth of strains was best on gonococcal agar with added fetal calf serum (GC-HgS). However, three strains were isolated only on Mueller-Hinton base (MH-base). GC-HgS was compared with MH-HB for the isolation of H. ducreyi from 201 patients with clinical chancroid. Seventy-one percent of cultures were positive on GC-HgS, and 61% were positive on MH-HB (P < .005); however, 10% of cultures were positive only on MH-HB. The use of the two media together increased the yield of positive cultures to 81%. Thus maximal rates of isolation of H. ducreyi from clinical specimens requires the use of two media, GC-HgS and MH-HB.

Laboratory diagnosis of Haemophilus ducreyi: Sensitivity of culture media

Laboratory confirmation of the clinical diagnosis of chancroid requires the isolation of Haemophilus ducreyi. Enriched gonococcal (GcHbS) and Mueller-Hinton agar (MHHb) both support the growth of most strains of H. ducreyi. In this study we compared the isolation rate of H. ducreyi on GcHbs and MHHb media in 111 men with genital ulcer disease. A second culture was obtained in 84 men at 48 hr in order to determine the reproducibility of H. ducreyi culture. The sensitivity of a single and a sequential pair of cultures on GcHbS was 67% and 74%, respectively, on men with presumed chancroid. The sensitivity of the MHHb as a single culture was 53%. Using both media for the initial culture of genital ulcers, and repeating the culture on GcHbs at 48 hr, increased the sensitivity of the isolation of H. ducreyi to 92% in men who had no prior antimicrobial use and who had no laboratory evidence of primary syphilis.

Leukocyte esterase urine strips for the screening of men with urethritis--use in developing countries.

BACKGROUND AND OBJECTIVES--The leukocyte esterase (LE) strip is a useful tool for the screening of men with urethritis. In developing countries, where laboratory facilities are limited, and sexually transmitted diseases endemic, simple and inexpensive diagnostic tests which perform well, would be of great value. METHODS--Men presenting with urethritis to a referral clinic for sexually transmitted diseases in Nairobi, Kenya participated in this cohort analytical study. First-void urine was collected for LE dipstick testing as part of the diagnostic work-up. The results of the dipstick measurement were compared with the laboratory detection of Chlamydia trachomatis and Neisseria gonorrhoeae. RESULTS--Of 200 men with symptoms of urethritis, 33 (17%) had a pathogen detected from the urethra or the urine. Chlamydia was detected in urine by PCR in 22 (11%), and gonorrhoea was cultured from the urethra in 11 (6%). Esterase activity (trace or greater) had a sensitivity of 76%, a specificity of 80%, a positive predictive value of 42% and a negative predictive value of 94% for the presence of chlamydia or gonorrhoea. CONCLUSIONS--The use of the LE dipstick for the screening of men with symptomatic urethritis can improve diagnostic accuracy and reduce the amount of empiric antimicrobial therapy. The low detection rate of chlamydia in these men with a clinical diagnosis of nongonococcal urethritis needs further study.

Evaluation of a rapid membrane-based assay (HIV-CHEK) for detection of antibodies to HIV in serum samples from Nairobi.

We evaluated a rapid membrane-based assay (HIV-CHEK) for detection of antibodies to HIV using 737 serum samples in Nairobi, Kenya. The rapid assay had a sensitivity of 96.3% and specificity of 99.8% when compared with enzyme-linked immunosorbent assay (ELISA) and Western blot assay. Results were similar using fresh or previously frozen serum samples, although the latter occasionally left debris on the assay device membrane yielding uninterpretable results. This rapid HIV assay may be of particular use in developing countries where laboratory resources are limited.

Early detection of HIV-1 in men from Kenya using a synthetic peptide and a p24 antigen enzyme-linked immunosorbent assay.

This paper reports the findings of a study on human sera with a known HIV-1 seroconversion date using a third-generation enzyme-linked immunosorbent assay (ELISA). The third-generation techniques would be tested against the first-generation viral lysate-based ELISA for detection of HIV-1 antibodies. Serum or plasma testing for p24 antigen is an alternate serologic testing approach used to detect the p24 antigen which is often more readily detectable than the anti-HIV-1 antibody in ELISA testing. This study was conducted from a prospective cohort of men that presented at the Nairobi Special Treatment Clinic Kenya with genital ulcers. Of the 813 men tested 191 (24%) were HIV-1 positive at their initial clinic visit. Of the remaining 622 men who tested seronegative on their initial visit 285 (46%) continued to return to the clinic; 37 men of this group of 285 (13%) subsequently tested HIV-1 positive. The initial group of 191 men formed one study group while the 37 men who developed seropositivity formed a second study group. The ELISA test kit detected seroconversion earlier than the viral lysate kits in 9 of 17 (53%) paired sera. The mean time of p24 antigen detection was 1.6 +or- 0.9 weeks post HIV exposure while HIV-1 antibodies showed a mean detection time of 4.1 +or- 2.5 weeks post HIV exposure. This study demonstrates that third-generation synthetic peptide-based ELISA of sera detects HIV-1 antibodies earlier than first-generation viral lysate-based ELISA. Also if present p24 antigen can be found early in the infection cycle.

Prophylaxis of Gonococcal and C hlam ydial Ophthalmia Neonatorum: A Comparison of Silver Nitrate and Tetracycline

We evaluated the use of silver nitrate drops and tetracycline ointment for the prophylaxis of ophthalmia neonatorum in a controlled trial involving 2732 newborns in Nairobi, Kenya. The overall rates of prevalence of intrapartum maternal gonococcal and chlamydial infection were 6.4 and 8.9 percent, respectively. After prophylaxis with silver nitrate, the incidence rates of gonococcal, chlamydial, and nongonococcal, nonchlamydial ophthalmia neonatorum were 0.4, 0.7, and 6.2 percent, respectively, whereas after prophylaxis with tetracycline, the rates were 0.1, 0.5, and 4.5 percent. The attack rates of gonococcal ophthalmia neonatorum in newborns exposed to Neisseria gonorrhoeae at birth were 7.0 percent in those receiving silver nitrate and 3.0 percent in those receiving tetracycline (95 percent confidence interval for the difference in rates, -3.4 to 11.4 percent). As compared with historical controls, the incidence of gonococcal ophthalmia neonatorum decreased 83 percent among infants treated with silver nitrate and 93 percent among those treated with tetracycline. Failure of prophylaxis was associated with postpartum maternal endometritis (P = 0.05). Among newborns exposed to maternal infection with Chlamydia trachomatis, chlamydial conjunctivitis developed in 10.1 percent given silver nitrate and in 7.2 percent given tetracycline (95 percent confidence interval for the difference in rates, -4.7 to 10.5 percent), yielding reductions in the incidence of chlamydial ophthalmia of 68 and 77 percent, respectively, as compared with the historical controls. We conclude that tetracycline is as effective as silver nitrate in preventing gonococcal ophthalmia neonatorum.