Israel Medical Association Journal

Background: An outbreak of pertussis occurred in a daycare center with 87.5% vaccination coverage.

Objectives: To assess the effectiveness of the acellular pertussis vaccine and prevention of pertussis after chemoprophylaxis with azithromycin.

Methods: We studied 31 daycare children aged 3–5.5 years exposed to a child with pertussis. Nasopharyngeal swabs were obtained for Bordetella pertussis culture and polymerase chain reaction initially, and at days 21 and 60 of follow-up, in cases exhibiting symptoms.

Results: Of the 31 daycare children 6 (19%) tested positive for B. pertussis by PCR[1], 4 of whom had not been vaccinated against the disease. Of the two vaccinated children who contracted pertussis, one had milder symptoms and the other was asymptomatic. The incidence of pertussis was significantly lower in the vaccinated group (2/27) than in the unvaccinated group (4/4) (P = 0.000), with efficacy of the vaccine calculated to be 92.5%. Azithromycin chemoprophylaxis was taken only by 14 of the 25 exposed children (56%). On day 21 follow-up, there was no further laboratory-diagnosed B. pertussis cases in any of the exposed children, regardless of whether or not chemoprophylaxis was taken.

Conclusions: Based on the children’s clinical manifestations and PCR findings a pertussis outbreak had occurred in the daycare center studied. Our findings support the importance of pertussis vaccination since all the unvaccinated children in the daycare center contracted the infection.

Objectives: To assess the relative efficacy of clinical and laboratory methods in the diagnosis of Bordetella pertussis by patient age and immunization status.

Methods: We compared the clinical and laboratory diagnosis of B. pertussis in 87 pre-vaccinated, 78 recently vaccinated, and 75 post-vaccinated children with suspected pertussis. Serum and nasopharyngeal swabs were obtained for serology, culture and polymerase chain reaction.

Results: PCR[1] and culture identified 41% and 7% of patients with B. pertussis, respectively (P < 0.001). All positive cultures were PCR-positive. Positive PCR was less common among those recently vaccinated than among those in the pre- (P < 0.001) and post-vaccinated groups (P < 0.05). Positive culture was more common among those pre-vaccinated than among those recently vaccinated (P < 0.01). Positive tests for immunoglobulin M and A were more common among the post-vaccinated than the pre- and recently vaccinated (P < 0.001), respectively. Logistic regression analyses revealed that clinical criteria have no significant association with infection in recently and post-vaccinated children. Among the pre-vaccinated children, whoop and cough duration were associated with a positive PCR (odds ratio 7.66 and 0.5, P < 0.001). Seventy-six percent of pre-vaccinated, 39% of recently vaccinated and 40% of post-vaccinated children with positive PCR did not meet the U.S. Centers for Disease Control diagnostic criteria for B. pertussis.

Conclusions: PCR is a useful tool for pertussis diagnosis, particularly in pre-vaccinated infants. The yield of culture and serology is limited, especially among pre- and recently vaccinated children. In pre-vaccinated infants with whoop and less than 2 weeks of cough, PCR testing should be implemented promptly.

Background: Non-gonococcal urethritis is the most common clinical diagnosis for men seeking care at sexually transmitted disease clinics.

Objective: To identify the pathogens involved in NGU[1] among males attending an Israeli STD clinic.

Methods: During 19 months spanning September 1996 to July 1998 we investigated a cohort of 238 male patients attending the Bnai Zion Medical Center STD[2] clinic with a clinical presentation of urethritis. Intraurethral swab specimens were tested for Neisseria gonorrhea, Ureaplasma urealyticum, Mycoplasma hominis, and Trichomonas vaginalis by culture and for herpes simplex virus by antigen detection. First voiding urine for Chlamydia trachomatis was done by polymerase chain reaction. The specific seropositivities of HSV[3] types 1 and 2 were tested by enzyme-linked immunosorbent assay.

Results: From among 238 males with dysuria or urethral discharge an etiology for urethritis was found for 71 (29.8%). N. gonorrhea was recovered in only three men (4.2%). In the remaining 68 NGU patients C. trachomatis (35/68, 51.5%) and U. urealyticum (31/68, 45.6%) were the most common infecting and co-infecting pathogens (P < 0.0001). M. hominis and T. vaginalis were found in 9/68 (13.2%), and 1 patient, respectively. HSV was recovered from the urethra in 7/68 males (10.3%) – 3 with HSV-1, 2 with HSV-2, and 2 were seronegative for HSV. None of these males had genital lesions. Although a single etiologic agent was identified in 45/68 infected men (66.2%), co-infection was common: 2 organisms in 15 (22%) and 3 organisms in 8 (11.8%).

Conclusion: C. trachomatis and U. urealyticum were the most common infecting and co-infecting pathogens in this cohort of men with NGU. Unrecognized genital HSV infections are common in males attending our STD clinic and symptomatic shedding of HSV occurs without genital lesions. Still, the microbial etiology in this group remains unclear in many patients despite careful microbiologic evaluation.