Hugh C. Dillon

Prospective studies of group B streptococcal infections in infants.

The incidence of GBS colonization at birth was determined prospectively among 96% of 2,407 infants born over a 12-month period in an urban community hospital. GBS were recovered from one or more of the four sites cultured in 290 (12.5%) of these newborn infants, 91 of whom were heavily colonized (3 to 4 sites positive). Sepsis or meningitis occurred in 13 infants, an attack rate of 5.4/1,000 live births. Attack rates for early and late onset disease, respectively, were 3.7 and 1.7 per 1,000 live births. All serotypes were found to cause disease. The incidence of early sepsis was strikingly high (8%) in heavily colonized infants. Those colonized at 1 to 2 sites were at no greater risk than noncolonized infants. The maternal vaginal colonization rate at delivery was 19%, with acquisition from the mother documented as the primary source of the organism in early onset infections. Perinatal events, including maternal complications and signs of illness at or immediately after birth, suggested ascending infection with exposure in utero to be likely in six infants. Passive acquisition of GBS (intrapartum exposure) probably occurred in the three remaining early onset cases. This mechanism was also likely responsible for five nonbacteremic infections. The four infants with late onset sepsis or meningitis were not colonized at birth or when discharged from the nursery (day 3); a possible maternal source for infection was found in only one of these infants.

Clinical and epidemiologic studies of pneumococcal infection in children

Streptococcus pneumoniae was isolated from 1310 children in a 5-year period from 1979 through 1984. There were 44 cases of meningitis, 172 bacteremic infections, 787 cases of otitis media and 307 respiratory and miscellaneous isolates. The majority of infections could be accounted for by a small number of serotypes, with types 3, 6, 14, 19 and 23 predominating. Most infections (70%) occurred in infants younger than 2 years of age. However, nearly one-fourth of those suffering systemic illness had some underlying condition which may have contributed to their risk for infection, even beyond 2 years of age. Ten of the 12 deaths occurred in patients with altered host defenses. Characteristics of pneumococcal disease and the distribution of serotypes are discussed in relation to the work of other investigators over the past 50 years.

A prospective study of group B streptococcal bacteriuria in pregnancy

Bacteriuria in pregnancy was prospectively studied in 569 women, with specific reference to group B streptococcal infection. Forty-six patients (8%) had bacteriuria, including 14 with group B streptococcal infection; group B streptococci (GBS) were exceeded in frequency only by Escherichia coli. Two thirds of the bacteriuric patients remained asymptomatic. The outcome of pregnancy was studied in 41/46 bacteriuric patients, including all those with group B streptococcal infection. Two pregnancies ended in intrauterine fetal death, and one neonate developed group B streptococcal sepsis; all three complications occurred in the 14 women with group B streptococcal bacteriuria. Diabetes mellitus appeared to increase the risk of group B streptococcal bacteriuria. This study revealed that group B streptococcal bacteriuria is more common in pregnancy than was previously suspected and suggests that culture methods to detect GBS should be used in bacteriuria screening programs done in pregnancy. In terms of perinatal infection risk, screening for group B streptococcal bacteriuria at or near the time of delivery may be more meaningful than other group B streptococcal surveillance culture studies.

Puerperal and perinatal infections with group B streptococci

Twenty-one patients were seen with puerperal sepsis owing to group B streptococci (GBS), resulting in an attack rate of 2/1,000 deliveries. Most were young primiparous black women from a population with a known high incidence of GBS carriage. The association among abdominal delivery, endometritis, and puerperal sepsis was striking. Cultures of the birth canal or lochia were commonly positive for the same serotype recovered from the blood. Forty-seven patients with nonbacteremic GBS infections were seen; 27 had endometritis or amnionitis. Twenty patients had GBS urinary tract infection: Eight infections occurred prenatally, seven at delivery, and five post partum. Seven neonates developed serious GBS infections; intrauterine exposure occurred in at least four cases. Fetal exposure to GBS also occurred in three of four cases in which parturients with GBS bacteremia were delivered of their infants by cesarean section. Because of the high incidence of puerperal and perinatal GBS infections in this population, antibiotic prophylaxis regimens may be beneficial.

Twin pregnancies: Incidence of group B streptococcal colonization and disease

Twin PREGNANCIES, responsible for 1% of births, account for 4 to 10% of all perinatal deaths?. 2 Premature birth appears to be the greatest hazard. Complications of delivery, intrauterine growth retardation, and hemodynamic abnormalities represent additional risks to the twin. 2 Naeye et aP have suggested that the amniotic fluid infection syndrome may be the most common identifiable cause of perinatal death in twins, being implicated in 16 to 38% of twin deaths, depending upon the population studied. Beta hemolytic streptococci, including members of serologic group B, are among tile causes of the syndrome. 4 Group B streptococcal infection in twins has been described, 5-7 but prospective data are lacking. Our prospective studies of GBS infections in infants have been in progress for several years. Data from the first year of investigation, recently reported, ~ included one set of twins who died with fulminant GBS sepsis. Additional cases, septicemia in a mother and one of her twin infants, prompted this analysis of the outcome of twin pregnancies in this population. An increased risk of GBS !nfection in twin pregnancies was strikingly evident.

The natural history of streptococcal skin infection: Prevention with topical antibiotics

An investigation on the natural history of streptococcal skin infection was done in fifty-nine children in a rural day care setting. A double-blind study for prevention of streptococcal pyoderma was done during the peak season for skin infection. Triple antibiotic ointment, containing bacitracin, polysporin, and neomycin, was compared to placebo ointment. Ointments were applied thrice daily for minor skin trauma; mosquito bites and abrasions were predominant. Cultures of normal skin surfaces were taken for group A streptococci each week of the 15-week study period. Skin lesions were cultured whenever present. Eighty-one percent of the fifty-nine patients had positive normal skin cultures on one or more occasions. Nineteen children (32%) developed streptococcal pyoderma. Infection occurred significantly more often in children using placebo ointment than in those using topical antibiotic (47% vs 15%; p = 0.01). The infecting strain was first recovered from normal skin surfaces in 67% of placebo patients and in two of the four patients using antibiotic ointment. This study further confirms the importance of skin carriage of group A streptococci as a precursor to pyoderma and demonstrates the importance of minor skin trauma as a predisposing factor. Topical antibiotics may be useful in preventing streptococcal pyoderma, especially in children known to be at increased risk for such infection.

Risk factors for perinatal group B streptococcal disease after amniotic fluid colonization

A group of 1031 parturient women at high risk for intraamniotic infection were studied. Women in whom group B streptococci grew from cultures of the amniotic fluid did not differ in clinical risk factors when compared with similar parturient women without group B streptococcal colonization of amniotic fluid. Patients who had perinatal group B streptococcal disease (maternal or neonatal bacteremia) did not differ from those without disease, by maternal or neonatal acute antibody levels or antibody response, inoculum size, or serotype of the colonizing strain.

Treatment of staphylococcal skin infections: A comparison of cephalexin and dicloxacillin

Cephalexin, given twice daily, and dicloxacillin, given four times daily, were compared in a randomly controlled study for the treatment of staphylococcal skin and skin structure infections. Among 70 evaluable patients, 57 had staphylococcal bullous impetigo. The remaining 13 patients had bullous impetigo with streptococcal or mixed streptococcal-staphylococcal cultures (6 patients), abscess (4 patients), or cellulitis with pyoderma (3 patients). Staphylococci were recovered from lesions of 64 of the 70 evaluable patients; all strains were sensitive to both cephalexin and dicloxacillin, but only 2 of the 64 strains were susceptible to penicillin G. Cephalexin and dicloxacillin proved equally effective. Treatment failures were uncommon (1 patient in each group), and recurrences (3 patients in each group) were limited to patients with bullous impetigo. In general, patients with staphylococcal bullous impetigo responded promptly, with clearing of lesions evident within the first week, but delayed healing with persistence of staphylococci in lesions was more common in the group receiving dicloxacillin. Twice-daily dosing with oral antibiotics is obviously convenient and may enhance compliance. Twice-daily therapy with cephalexin for staphylococcal skin and skin structure infections can be recommended with confidence.

Type-specific streptococcal antibodies in amniotic fluid.

Type-specific antibodies against group B streptococcal and pneumococcal capsular antigens were measured in 68 amniotic fluid samples from healthy women between 16 and 20 weeks of pregnancy. Mean antibody levels ranged from 0.13 to 0.61 microgram/ml, with few samples having greater than 1 microgram/ml against any antigen. The role of antibodies in protection against intrauterine infection is discussed.

Susceptibility of Staphylococcus aureus to Cefaclor and Cephalothin: Laboratory and Clinical Studies

In vitro susceptibility tests of 201 strains of Staphylococcus aureus by agar dilution revealed 90% to be susceptible to 8 μg or less of cefaclor per ml. Strains from hospitalized children and adults were more often resistant than those from patients with bullous impetigo. Cephalothin was more active than cefaclor against all strains tested. Results with disk tests, including those strains examined from the clinical investigation, revealed some discrepancies in identifying strains more resistant to cefaclor. In clinical studies, cefaclor proved quite effective for the treatment of bullous impetigo. Of 73 patients, 90% were cured and 7% improved after completing 5 or more days of treatment. Prompt improvement was noted among most patients seen 3 to 5 days after treatment was begun. One patient experienced mild diarrhea. There were no other adverse or toxic manifestations attributable to therapy.