Diversity and sharing of Haemophilus influenzae strains colonizing healthy children attending day-care centers

BACKGROUND: Children attending day-care centers (DCCs) are at risk for Haemophilus influenzae nasopharyngeal colonization and acute otitis media. The degree to which a given strain circulates within a day-care center and the heterogeneity of strains among DCCs in a geographic area are not well-characterized. This study describes the prevalence rates of H. influenzae colonization in a large number of children attending day-care centers and examines the genetic diversity of colonizing strains and the degree of sharing among children. METHODS: Throat cultures were collected from 198 healthy children <3 years old attending 16 day-care centers in Michigan. All H. influenzae isolates were genetically typed by enterobacterial repetitive intergenic consensus PCR as the initial screening technique to identify unique strains within each child. Pulsed field gel electrophoresis was used subsequently to examine the genetic diversity of strains between children. RESULTS: There were 127 (64%) children colonized with H. influenzae. Wide variation in rates of colonization was identified among day-care centers (0 to 95%). A total of 179 genetically unique H. influenzae strains were isolated, and 47 children (37%) were colonized with 2 or more genetically distinct H. influenzae organisms. Evidence of sharing of the same strain in different children was found in 13 of 15 colonized DCCs and 23% of genotypically unique strains were shared. CONCLUSION: The degree of sharing of H. influenzae among children in this study suggests transmission of these potentially pathogenic microorganisms in day-care centers.     

Predictors for Haemophilus influenzae colonization, antibiotic resistance and for sharing an identical isolate among children attending 16 licensed day-care centers in Michigan

BACKGROUND: Nontypable Haemophilus influenzae is an important cause of otitis media in children. Children attending day-care centers are at an increased risk for nontypable H. influenzae colonization and otitis media. We describe the prevalence of nontypable H. influenzae colonization, antibiotic resistance and predictors for colonization and sharing an identical isolate with at least 1 other child in the same day-care centers among children attending 16 day-care centers. METHODS: Throat swabs of 198 children < 3 years old attending 16 day-care centers were cultured for H. influenzae. Day-care center directors and parents completed risk factors questionnaires. Nontypable H. influenzae isolates were screened for antibiotic resistance and genotyped. Statistics were performed using SAS software (SAS Institute, Inc., Cary, NC). RESULTS: We isolated 179 unique nontypable H. influenzae strains from 127 participants. Colonization ranged from 0% to 95% among day-care centers. As individual factors, exposure to tobacco smoke was associated with colonization (P = 0.05), and racial self-identifications as "other" (nonwhite, nonblack) was protective (P = 0.035), whereas as "black" was protective for sharing (P = 0.03). Pacifier use was associated with sharing (P = 0.04), but not with colonization. As day-care centers factors, rates of colonization and sharing were higher in day-care centers with > or = 5 classrooms (P < 0.01 and P = 0.03), with such suboptimal hygiene habits as minimal hand washing by staff after eating (P < 0.002 and P < 0.01) or by children after wiping their own nose (P = 0.01 and P = 0.003). Of colonized children, 41% presented a beta-lactamase-producing strain. Colonized children were more likely to carry resistant strains if they were taking an antibiotic (P = 0.02). CONCLUSION: Although day-care center colonization varied, the overall colonization rate was high. Colonization with nontypable H. influenzae, with beta-lactamase-producing strain and sharing were, mostly, associated with modifiable risk factors.     

Incidences of nasopharyngeal colonization of respiratory bacterial pathogens in Japanese children attending day-care centers

BACKGROUND: In Japan, many younger children attending day-care centers tend to frequently experience acute respiratory infections and prolonged otitis media. OBJECTIVES: To evaluate the carriage rate of respiratory bacterial pathogens in children attending day-care centers in our district. METHODS: Nasopharyngeal cultures of 156 healthy children between the ages of 1 month and 5 years were conducted at two day-care centers in Japan, in April 1999. The carriage rates of four major pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus) and the antibiotic susceptibilities of the isolates were examined. RESULTS: Streptococcus pneumoniae, H. influenzae, M. catarrhalis and S. aureus were detected in 94 (60.3%), 83 (53.2%), 54 (34.6%) and 28 (17.9%) children, respectively. A total of 141 (90.4%) children carried at least one pathogen among these four pathogens and 87 (55.8%) children carried more than one pathogen. Fifty-seven of the 94 (60.6%) S. pneumoniae isolates were penicillin-intermediately or highly resistant strains of S. pneumoniae (PISP/PRSP). Beta-lactamase producing H. influenzae was not detected. Twelve of the 28 (42.9%) S. aureus isolates were methicillin-resistant. The incidence of colonization by PISP/PRSP in children younger than 3 years (43/69, 62.3%) was significantly higher than that in children aged 3-5 years (14/87, 16.1%) (P < 0.0001). CONCLUSIONS: We conclude that the rates of colonization by respiratory bacterial pathogens, especially by antibiotic-resistant strains, were high in children attending day-care centers in our district, suggesting their horizontal spread among children in day-care centers. Considering that the majority of children attending day- care centers carried one or more of the bacterial pathogens, the judicious use of antimicrobials will be required to prevent the increase of antibiotic-resistant rates among the colonizing pathogens.     

Haemophilus influenzae type b colonization in household contacts of infected and colonized children enrolled in day care

Strategies for management of children attending day-care facilities after a case of Haemophilus influenzae type b disease are controversial. The success of chemoprophylaxis in preventing subsequent cases has been variable. Failure of rifampin prophylaxis as currently recommended may result from usage limited to direct contacts of the index patient. This prospective study was designed to ascertain the extent of colonization in household contacts of colonized children attending day-care facilities with an index case of H influenzae disease. Outer membrane protein analysis was used to determine similarity between strains isolated from contacts and index patients. Of children attending six day-care facilities, 15% were colonized with subtypes of H influenzae identical with those of their respective index patients, and 7% of children were colonized with different subtypes. Colonization with identical outer membrane protein subtypes in children from day-care homes was more frequent than in the larger day-care centers (91% v 8%, P less than .00001). Within families of children with identical outer membrane protein subtypes, 25% of household members (17% of parents and 44% of siblings) were colonized despite lack of direct contact with the index patients. This colonization rate was comparable to that of household contacts of index patients (26%). Among household contacts of index patients, especially siblings, colonization with H influenzae tended to be lower if the patient attended day care than if the patient did not attend day care (17% v 73%; P = .05 for siblings). We have found that household contacts of colonized day-care children are a reservoir of H influenzae.(ABSTRACT TRUNCATED AT 250 WORDS)     

When co-colonizing the nasopharynx haemophilus influenzae predominates over Streptococcus pneumoniae except serotype 19A strains to cause acute otitis media

Of 368 acute otitis media (AOM) cases among 7-valent pneumococcal conjugate-vaccinated children, 43.5% were colonized by multiple otopathogens in the nasopharynx but only 7.1% experienced polymicrobial AOM. When co-colonization occurred, Haemophilus influenzae predominated over all Streptococcus pneumoniae strains except 19A strains to cause AOM. Haemophilus influenzae and Streptococcus pneumoniae both predominated over Moraxella catarrhalis to cause AOM.     

Antibody response to outer membrane of noncapsulated Haemophilus influenzae isolated from the nasopharynx of children with pneumonia

In a prospective study aimed at determining the etiology of community-acquired pneumonia in children nasopharyngeal cultures and paired serum samples were obtained from 336 consecutive children ages 6 weeks to 15 years with pneumonia, 167 hospitalized and 169 outpatients. Results regarding Haemophilus influenzae are reported here. Blood cultures obtained from 127 of the hospitalized patients did not yield growth of H. influenzae. H. influenzae was isolated from the nasopharynx of 88 children. Seventy-three strains were noncapsulated, 2 were type b, 2 were type f and 11 were not serotyped. Paired serum samples were available from 38 children with growth of noncapsulated H. influenzae in the nasopharynx as the only potential pathogen. Sixteen of them responded with significant increases in serum antibodies against outer membrane preparations prepared from their own nasopharyngeal isolates. Thirty-eight age- and sex-matched control children with pneumonia without growth of H. influenzae in the nasopharynx served as controls. Sera from each control patient were tested for antibodies against two strains of noncapsulated H. influenzae. Of those, 4 had significant increases in antibodies against one or both outer membrane preparations. The increases in serum antibodies against the outer membrane of noncapsulated strains of H. influenzae indicate that this organism might be a cause of pneumonia in some children.     

Prospective surveillance of Haemophilus influenzae type b disease in Dallas County, Texas, and in Minnesota

Among children less than 12 years of age residing in Dallas County, Texas, and in the state of Minnesota we conducted prospective, active surveillance of invasive Haemophilus influenzae disease. During 18 months, 616 cases were identified, of which 600 were caused by type b organisms. The annual incidence of disease was significantly greater in Dallas than in Minnesota (109 v 68/100,000 children younger than 5 years of age, P less than .001) and was greater in Dallas, even when rates for white children in the two regions were compared (P less than .001). Other regional differences were observed. In Dallas, a larger proportion of cases were in children attending day-care centers (27% compared with 12% in Minnesota, P less than .001) and more patients attended day care for greater than 40 h/wk (56% compared with 30% in Minnesota, P less than .001). Outer membrane protein subtyping of isolates revealed that in Dallas 6U isolates were associated significantly with cases in black children who attended day care. In Minnesota, but not in Dallas, isolates with subtype 1H were associated significantly with cases in children in day care. These data indicate that there are regional differences in the epidemiology of type b Haemophilus disease that may relate to differences in strains, day-care practices, or other unknown cultural or environmental factors. Finally, because only 15% of systemic Haemophilus disease in these regions occurred in children in the age groups recommended for vaccination (24 to 59 months), the new Haemophilus type b polysaccharide vaccine is expected to have a limited impact on the overall incidence of disease.     

Bacterial etiology of conjunctivitis-otitis media syndrome

Simultaneous cultures of conjunctivae and middle ear exudates were obtained from 20 episodes of the syndrome of purulent conjunctivitis and otitis media. Paired cultures from 18 episodes yielded Haemophilus influenzae at both sites. In two cases with prior topical antibacterial therapy of the conjunctivitis, H influenzae was isolated from the middle ear exudate only. Biotyping and outer membrane protein analysis of H influenzae isolates from five patients demonstrated that: conjunctival and middle ear strains were concordant in all cases, and all five patients had different strains. The conjunctivitis-otitis media syndrome is most often caused by strains of nontypable H influenzae of diverse clonotype.     

Clinical and bacterial characteristics of acute bacterial conjunctivitis in children in the antibiotic resistance era

BACKGROUND: Acute conjunctivitis is the most common eye disorder in young children. Bacteria are responsible for 54-73% of all cases. The goals of the study were to identify the rates of Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis in cases of bacterial conjunctivitis in children and to define antibiotic resistance rates. METHODS: During a 2-year study period, conjunctival swabs of children 2-36 months old were collected prospectively. Nontypable H. influenzae, S. pneumoniae and M. catarrhalis were defined as the study pathogens. Analyzed variables included demography, clinical presentation, bacteriologic results and susceptibility patterns. RESULTS: There were 428 patients enrolled. Of all cultures, 55% (237 of 428) yielded at least 1 of the study pathogens. H. influenzae and S. pneumoniae were isolated from 29 and 20% of cultures, respectively. beta-Lactamase production was found in 29% of H. influenzae isolates, and penicillin nonsusceptibility was observed in 60% of S. pneumoniae isolates. The most common S. pneumoniae serotypes were: 19F (14%); 6A and 14 (11% each). Nontypable S. pneumoniae was found in 12%. The 7-valent pneumococcal conjugate vaccine (PCV-7) could potentially cover 44% of all isolates. Conjunctivitis-otitis syndrome was found in 32% of patients, of whom 82% of cultures yielded H. influenzae. CONCLUSIONS: Antibiotic resistance rates are alarmingly high. Conjunctivitis-otitis syndrome, predominantly caused by H. influenzae, is quite common. The potential coverage of the PCV-7 in conjunctivitis is relatively lower than that reported in other pneumococcal infections. Our findings should alert physicians on the choice of appropriate antibiotic treatment, on the frequent copresence of acute otitis media and on the potential role of conjunctivitis in the spread of antibiotic-resistant pathogens.     

Etiology and Diagnosis of Neonatal Conjunctivitis

ABSTRACT. Chlamydia trachomatis was isolated from the most inflamed eye of 13 of 107 (12%) infants with neonatal purulent conjunctivitis and from none of 100 healthy infants ( p <0.01). Staphylococcus aureus was recovered from 49 (46%) inflamed eyes and from 8 (8%) healthy eyes ( p <0.01). Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catar-rhalis, Escherichia coli and Klebsiella pneumoniae were isolated from very few infants with conjunctivitis but not from controls. No organisms could be recovered from 23 (22%) infants with conjunctivitis and from 60 (60%) healthy infants (p<0.01). The incidence of neonatal purulent conjunctivitis was 107 (2%), of 5924 births. Eyes infected with C. trachomatis were significantly more inflamed than eyes from which S. aureus or no organisms could be isolated. Furthermore, conjunctival "psendomembranes" were associated with C. trachomatis. The age at onset of the chlamydial conjunctivitis was higher compared to the age at onset of conjunctivitis in which S. aureus or no organisms were isolated.     

Etiology and diagnosis of neonatal conjunctivitis

Chlamydia trachomatis was isolated from the most inflamed eye of 13 of 107 (12%) infants with neonatal purulent conjunctivitis and from none of 100 healthy infants (p less than 0.01). Staphylococcus aureus was recovered from 49 (46%) inflamed eyes and from 8 (8%) healthy eyes (p less than 0.01). Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catarrhalis, Escherichia coli and Klebsiella pneumoniae were isolated from very few infants with conjunctivitis but not from controls. No organisms could be recovered from 23 (22%) infants with conjunctivitis and from 60 (60%) healthy infants (p less than 0.01). The incidence of neonatal purulent conjunctivitis was 107 (2%), of 5,924 births. Eyes infected with C. trachomatis were significantly more inflamed than eyes from which S. aureus or no organisms could be isolated. Furthermore, conjunctival "pseudomembranes" were associated with C. trachomatis. The age at onset of the chlamydial conjunctivitis was higher compared to the age at onset of conjunctivitis in which S. aureus or no organisms were isolated.     

Outbreak of Haemophilus influenzae type b meningitis in a day care center

Three cases of Haemophilus influenzae type b (Hib) meningitis in a Swedish day care center prompted the investigation of the nasopharyngeal carriage in attendees of that day care center (I), and among children in another day center (II) in the same city, but without meningitis cases. Because the evaluation of the spread of Haemophilus influenzae (Hi) isolates through a population, such as children in day care centers, requires stable identification markers for the bacteria, this study used multilocus enzyme electrophoresis to separate Hib carried by day care attendees from the disease-associated Hib clone. The three meningitis episodes were caused by the same clone of Hib (ET14). This and other Hib clones occurred in the healthy carriers. The frequency of H. influenzae carriage and composition of the H. influenzae flora differed between the two day care centers. Center I with the meningitis cases had a lower overall frequency of H. influenzae carriage, 11 of 40 (28%) compared with both the control day care center (57%) and previous studies. The main difference between the two day care centers was in the nontypable H. influenzae (HiNT) flora. The frequency of HiNT was higher in the center without Hib disease, and there was a higher degree of sharing of HiNT isolates among the children in Center II. This raised the question of an inverse relationship between carriage of HiNT and Hib infection. The results emphasized the importance of accurate identification of the disease isolate in order to estimate the risk of acquisition and dissemination to secondary cases.     

Risk factors for carriage of respiratory pathogens in the nasopharynx of healthy children. Ascanius Project Collaborative Group.

OBJECTIVES: To assess risk factors for nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in a large sample of healthy children. METHODS: In this point prevalence survey nasopharyngeal specimens were obtained from 1723 healthy children, ages 1 to 7 years, attending day-care centers or schools in 18 Italian cities. Written questionnaires for obtaining information about the demographics and medical history of the children were completed by the parents in the presence of a pediatrician. RESULTS: The overall carrier rate of respiratory pathogens was 17.9% (S. pneumoniae, 3.5%; H. influenzae, 11.9%; M. catarrhalis, 4.1%). Only 5% of S. pneumoniae strains were penicillin-resistant whereas approximately 40% were erythromycin-resistant. Beta-lactamase production was found in 5.8% of H. influenzae and 88.7% of M. catarrhalis isolates. By multivariate analysis age (< or = 3 years), having older siblings, a history of prolonged full-time day-care attendance and living in a rural area significantly influenced the odds of carrying nasopharyngeal respiratory pathogens, particularly in children ages 1 to 5 years. Sex, breastfeeding, passive smoking and recent upper respiratory tract infections were not significant variables. Antibiotic treatment in the previous 3 months did not affect nasopharyngeal carriage, whereas repeated treatments with a macrolide were associated with carriage of S. pneumoniae. CONCLUSIONS: Our results suggest that there is a strong and long term relationship between exposure to large numbers of children in the first years of life and nasopharyngeal carriage of all respiratory pathogens. In addition antimicrobial restrictive guidelines should be tailored to local microbiologic sceneries.     

Comparative efficacy of oral rifampin and topical chloramphenicol in eradicating conjunctival carriage of Haemophilus influenzae biogroup aegyptius. Brazilian Purpuric Fever Study Group.

Persistent conjunctival carriage of the Haemophilus influenzae biogroup aegyptius (Hae) strain (BPF clone) responsible for Brazilian purpuric fever (BPF) has been documented. Topical chloramphenicol is routinely used to treat conjunctivitis in areas affected by BPF in Brazil. Although the BPF clone is susceptible to chloramphenicol, we observed a number of children treated with topical chloramphenicol for conjunctivitis who still developed BPF. During an investigation of an outbreak of BPF in Mato Grosso State, Brazil, we compared oral rifampin (20 mg/kg/day for 4 days) with topical chloramphenicol for eradication of conjunctival carriage of H. influenzae biogroup aegyptius among children with presumed BPF clone conjunctivitis. Conjunctival samples were taken for culture on the day treatment was initiated and a mean of 8 and 21 days later. At 8 days the eradication rates for oral rifampin and topical chloramphenicol were 100 and 44%, respectively (P = 0.003); at 21 days they were 100 and 50% (P = 0.01). Oral rifampin was more effective than topical chloramphenicol for eradication of the BPF clone and may be useful in prevention of BPF.     

Nasopharyngeal carriage of antibiotic-resistant Haemophilus influenzae in healthy children.

We selected 16 schools representing a broad socioeconomic cross-section of metropolitan Omaha and obtained nasopharyngeal cultures for Haemophilus influenzae from 1,084 healthy 4- to 7-year-old children. We found that 34.2% of the children carried nontypable strains and 2.0% carried type b strains. Carriage rates were not influenced by recent illness, family size, or number of people sharing a bedroom. The prevalence of ampicillin-resistant H influenzae in the sample population was 0.9% for nontypable strains and 0.4% for type b strains; it was not significantly different in the group of children who had recently used beta-lactam antibiotics. One child carried a nontypable strain which was resistant to both chloramphenicol and tetracycline, the first chloramphenicol-resistant H influenzae detected in Omaha. A survey of healthy children may be a useful method for projecting a community's risk of disease caused by ampicillin-resistant H influenzae. Among the nasopharyngeal isolates from healthy children, 2.7% of nontypable strains and 18.2% of type b strains were resistant to ampicillin (P less than .01). During the same five-month period in Omaha, clinical failure in the treatment of otitis media with ampicillin was uncommon and four (20.0%) of 20 cases of H influenzae type b bacteremia and meningitis were caused by ampicillin-resistant organisms.     

Lack of correlation of in vitro adherence of Haemophilus influenzae to epithelial cells with frequent occurrence of otitis media

The adherence to human epithelial cells, biotype and capsular type of 175 Haemophilus influenzae cultured from the upper respiratory tract were studied in a prospective study of children with recurrent otitis media. Forty-three children who had greater than 2 episodes of acute otitis media (AOM) during the first year of life were followed for at least 1 year. Cultures of the oropharynx were done periodically, and the middle ear fluid (MEF) was cultured at the time of AOM. H. influenzae was recovered from MEF in 44% of the 136 AOM episodes recorded. Thirty-one children had at least one episode of AOM caused by H. influenzae; the remaining 12 children, designated as "controls," had no otitis or had AOM caused by other organisms. The possible differences between carriage and infection strains were evaluated by comparison of MEF and oropharyngeal isolates, by pairwise comparison of MEF and oropharyngeal isolates and by pairwise comparison of multiple isolates from each host recovered at the time of AOM and during infection-free intervals. No significant differences in patterns of adherence, capsular type or biotype were found. The lack of correlation between these characteristics and infection suggests either that H. influenzae organisms have determinants of virulence yet to be defined or that variations in host susceptibility permit infection by the strain colonizing the upper respiratory tract. Adherence per se may be less important in the development of infection than in establishing and maintaining colonization within the host.     

Acute epiglottitis: therapeutic consequences of change in the resistance of Haemophilus influenzae serotype B

From July 1977 to May 1987, 27 children with acute epiglottitis were treated in our intensive care unit. Haemophilus influenzae type b was identified by positive blood culture in 14 of 27 cases. Until 1983 the first 11 children were treated with ampicillin (100 mg/kg) for a mean duration of 10 days according to the standard therapeutic regimen and/or proven sensitivity from blood cultures (5 of 11 cases). The first finding of an ampicillin resistant Haemophilus influenza type b strain dates from January 1984. From this date on initial antibiotic therapy consisted of cefotaxime (100 mg/kg). Blood cultures proved good sensitivity to cefotaxime (100%) but an increasing rate of resistance to ampicillin (3 of 9 identified strains). Haemophilus influenzae septicemia in acute epiglottitis is verified by the isolation of Haemophilus influenzae type b from blood cultures (14/27) and the additional pneumonias (14/27). Additional meningitis as seen is a very rare complication. Facing these potentially life-threatening secondary foci of this invasive infection, an effective antibiotic therapy is mandatory. Our experiences confirm recommendations from US, UK, Australia, and Spain, where ampicillin was replaced by third generation cephalosporins as initial antibiotic therapy due to the increasing rate of resistance of Haemophilus influenzae type b.     

Short term oral cefixime therapy for treatment of bacterial conjunctivitis.

BACKGROUND: There have been few controlled studies evaluating treatment of bacterial conjunctivitis beyond the newborn period. Topical therapy of bacterial conjunctivitis achieves a clinical cure but does not prevent acute otitis media (AOM). OBJECTIVES: The aim of this study was to compare systemic antibiotic therapy (cefixime) with topical therapy with polymyxin-bacitracin for treatment of acute bacterial conjunctivitis with regard to clinical and bacteriologic cure and prevention of AOM. METHODS: This study was a randomized, double blind, placebo-controlled trial of polymyxin-bacitracin ointment and oral placebo vs. topical placebo and oral cefixime in children with presumed acute bacterial conjunctivitis. Topical therapy was administered for 7 days; oral therapy was administered for 3 days. Bacterial cultures were obtained at entry and on Day 3 of treatment. Children were examined on Days 3 and 10 or if they worsened within 15 days of entry. RESULTS: Eighty children were enrolled in the study. Bacterial cultures of the conjunctiva were positive in 70% of children: Haemophilus influenzae (53.7%); Streptococcus pneumoniae (13.8%); H. influenzae and S. pneumoniae (1.2%); and Moraxella catarrhalis (1.3%). There were 7 (17.5%) bacteriologic failures among children receiving topical antibiotic and oral placebo and 15 (37.5%) bacteriologic failures among children receiving topical placebo and oral cefixime (P = 0.07 with Yates correction). There was no difference between study groups with regard to either clinical cure or the development of AOM. Nine children (11%), 5 who received active topical therapy and 4 who received active oral drug, developed AOM either during or within 15 days of study entry. CONCLUSION: Cefixime was not more effective than topical polymyxin-bacitracin in either the eradication of conjunctival colonization with respiratory pathogens or the prevention of AOM in children with acute bacterial conjunctivitis.     

Acute bacterial conjunctivitis. Bacteriology and clinical implications

We report the results of eye culture specimens, obtained from patients under 20 years of age, submitted to the Bacteriology Department of our institution from January 1 through April 30, 1983. A total of 72 specimens were positive for one or more strains of bacteria. The most commonly isolated bacteria was Hemophilus influenzae (34 strains, 42%), followed by Staphylococcus epidermidis (11 strains, 13.75%) and Streptococcus pneumoniae (9 strains, 11.25%). Mean age of patients with H. influenzae (excluding a 20-year-old patient) was 15 months with standard deviation of 13 months. Chloramphenicol and tetracycline showed excellent in vitro activity against bacteria of all age groups. Tetracycline may prove to be the drug of choice for the treatment of acute conjunctivitis if comparative clinical data support its in vitro superiority.     

Intermediate resistance of Streptococcus pneumoniae to penicillin in children in day-care centers.

This study was performed to determine the prevalence, serotypes and antibiotic susceptibility patterns of penicillin-resistant Streptococcus pneumoniae in children younger than 3 years of age in day-care centers in Houston, TX. Nasopharyngeal cultures were obtained on two occasions, in March and May, 1989, from 140 children in 4 day-care centers. All penicillin-resistant S. pneumoniae organisms isolated in this study had minimum inhibitory concentrations to penicillin of between 0.1 and 0.5 microgram/ml and were thus intermediately resistant. No highly resistant S. pneumoniae (minimum inhibitory concentration > or = 1.0 microgram/ml) was isolated in this study. Nasal carriage of S. pneumoniae occurred in 39% of children; carriage of intermediately resistant S. pneumoniae occurred in 4% of children. Of the 39% of children who carried S. pneumoniae, 11% carried intermediately resistant strains. In one day-care center with a prior history of intermediately resistant S. pneumoniae (Center 1), the prevalence of intermediate penicillin resistance was significantly (P = 0.047) higher than in the other three centers. Among children surveyed twice 15% of Center 1 children carried an intermediately penicillin-resistant strain at least once, whereas in the other centers 3% of children carried an intermediately resistant strain at least once. Sixty-two percent of intermediately penicillin-resistant strains were resistant to multiple antibiotics and all were serotype 14. Intermediately penicillin-resistant S. pneumoniae isolates were prevalent among young children in day-care centers in Houston and may persist in some day-care centers and become endemic.