Search PubMed⌕ Search

Biomedical subjects

Ron Dagan

Publications and source records attributed to Ron Dagan.

At least 91 records · Page 5Linked to original sources
PubMed2003

Effect of a nonavalent conjugate vaccine on carriage of antibiotic-resistant Streptococcus pneumoniae in day-care centers.

BACKGROUND: In the developed societies, day-care centers (DCCs) play an important role in the spread of antibiotic-resistant pneumococci both within the facility and from the facility to the community. This study was conducted to determine the effect of a nonavalent pneumococcal conjugate vaccine (PCV-9) on the carriage of antibiotic-resistant pneumococci in the DCC. SUBJECTS AND METHODS: Healthy DCC attendees ages 12 to 35 months were randomized to receive either PCV-9 or a control vaccine (conjugate meningococcus C vaccine) in a double blinded manner. Nasopharyngeal Streptococcus pneumoniae cultures were obtained from each subject before vaccination, monthly during the first year of follow-up and every 2 to 3 months during the second year of follow-up. For each isolate the serotype and antibiotic susceptibility were determined. RESULTS: A total of 132 and 130 evaluable toddlers received either PCV-9 or the control vaccine, respectively. In total 3748 cultures were obtained, of which 2450 (65%) were positive for S. pneumoniae. The resistance rates to penicillin, trimethoprim-sulfamethoxazole and erythromycin were 36, 35 and 16%, respectively. Resistance rates to > or =1 and > or =3 antibiotic categories were 52 and 9%, respectively. Antibiotic resistance was found mainly in the 5 serotypes included in the pneumococcal conjugate vaccines (6B, 9V, 14, 19F and 23F) and in 2 related serotypes (6A and 19A). In the vaccinated group a clear and significant reduction of the carriage rate of the serotypes included in the vaccine and the related serotype 6A as well as an increase in the carriage rate of the serotypes not included in the vaccine were observed. In parallel a significant decrease in carriage rate of antibiotic-resistant pneumococci was observed. The reduction of carriage of antibiotic-resistant pneumococci was seen in all age windows but was greater in the age window <36 months. CONCLUSIONS: The carriage rate of antibiotic-resistant S. pneumoniae, including multiply resistant S. pneumoniae, in DCC attendees is high. Pneumococcal conjugate vaccines seem to be an important tool for reducing the carriage rate of antibiotic-resistant pneumonia in DCCs.

Anti-Bacterial Agents↗
PubMed2003

Acute mastoiditis in Southern Israel: a twelve year retrospective study (1990 through 2001).

BACKGROUND: Acute mastoiditis is a serious complication of acute otitis media (AOM) and has been increasingly reported in the last decade. OBJECTIVES: To report the experience accumulated with acute mastoiditis at the Soroka University Medical Center, Beer-Sheva, Israel, in a period of increasing antimicrobial resistance with Streptococcus pneumoniae. PATIENTS AND METHODS: We reviewed the records of all children with acute mastoiditis hospitalized from 1990 through 2001. Acute mastoiditis was diagnosed when one or more of the physical signs of mastoiditis (swelling, erythema, tenderness of the retroauricular area and anteroinferior displacement of the auricle) were diagnosed in the presence of concomitant or recent (< or =4 weeks) AOM. RESULTS: One hundred sixteen episodes of acute mastoiditis occurred in 101 children age 2 months to 14 years (median, 25 months; 19% <1 year old). The average yearly incidence was 6.1 cases per 100 000 population <14 years old, with a significant increase in the number of cases during the study period. Acute mastoiditis was the first evidence of AOM in 10 (10%) patients. Fever >38 degrees C and >15,000 WBC/mm3 were present in 67 and 43% of cases, respectively. Irritability, retroauricular swelling, redness and protrusion of the auricle occurred more commonly in patients <3 years old (79, 90, 84 and 76% vs. 28, 42, 45 and 30%, respectively, in patients > or =3 years old; P < 0.002). Computed tomography scans were performed in 54 of 116 (47%) cases and revealed bone destruction in 38 (70%). Periosteal abscess and lateral sinus vein thrombosis were diagnosed in 8 and 2 patients, respectively. Simple mastoidectomy was done in 32 of 116 (28%) cases, after no response to intravenous antibiotics was observed; ventilation tubes were inserted in 12 patients. Cultures were obtained at admission in 83 (72%) episodes (71 by tympanocentesis and 12 from ear discharges). Overall 43 pathogens were isolated: 34 at admission; 14 at surgery; and 5 at both occasions. The most commonly isolated organisms were S. pneumoniae (14 of 43, 33%; 4 penicillin-nonsusceptible), Streptococcus pyogenes (11 of 43, 26%), nontypable Haemophilus influenzae (6 of 43, 14%), Pseudomonas aeruginosa (5 of 43, 12%) and Escherichia coli (4 of 43, 9%). All S. pneumoniae organisms were isolated between 1996 and 2001. CONCLUSIONS: (1) The incidence of acute mastoiditis in children in Southern Israel is greater than that reported in the literature; (2) a significant increase in the number of cases was recorded during the study period; (3) the clinical picture of acute mastoiditis was more severe in infants and young children; (4) the pathogen distribution in acute mastoiditis differs from that of AOM with significantly higher rates of S. pyogenes and lower rates of nontypable H. influenzae recovery; (5) penicillin-nonsusceptible S. pneumoniae played only a minor role in the etiology of acute mastoiditis in Southern Israel.

Acute Disease↗
PubMed2003

Bacteriologic and clinical efficacy of oral gatifloxacin for the treatment of recurrent/nonresponsive acute otitis media: an open label, noncomparative, double tympanocentesis study.

BACKGROUND: Gatifloxacin is an 8-methoxyfluoroquinolone with good activity against respiratory pathogens. OBJECTIVES: To document the bacteriologic and clinical efficacy of gatifloxacin in recurrent/nonresponsive acute otitis media (AOM). METHODS: One hundred sixty patients 6 to 48 months of age with recurrent/nonresponsive AOM received gatifloxacin suspension (10 mg/kg once daily for 10 days). Recurrent AOM was defined as > or =3 AOM episodes during the previous 6 months or > or =4 AOM episodes during the previous 12 months. Nonresponsive AOM was defined as AOM occurring < or =14 days after completing antibiotic treatment or not improving after > or =48 h of therapy. Middle ear fluid (MEF) obtained by tympanocentesis pretreatment (Day 1) and 3 to 5 days after initiation of treatment (Days 4 to 6) was cultured. Additional MEF cultures were obtained if clinical failure or recurrence of AOM occurred. Bacteriologic failure was defined by culture-positive MEF during treatment. Patients were followed until Days 22 to 28. Susceptibility was determined by broth microdilution. RESULTS: One hundred twenty-eight (80%) patients completed treatment, and 32 discontinued the study prematurely (adverse events, 17; lost to follow-up, 10; consent withdrawal, 3; and laboratory abnormalities, 2). From 89 patients (median age, 1 year; median number of prior AOM episodes, 4; range, 0 to 12), 121 pathogens were recovered: Haemophilus influenzae, 74 (61%); Streptococcus pneumoniae, 36 (30%); Moraxella catarrhalis, 9 (7%); and Streptococcus pyogenes, 2 (2%). The 36 S. pneumoniae isolates were susceptible to gatifloxacin (MIC50 0.25 microg/ml); 26 of 36 (72%) were penicillin-nonsusceptible (15 fully resistant). All 74 H. influenzae isolates were susceptible to gatifloxacin (MIC < or = 0.03 mg/ml). Fourteen of 74 (19%) and 9 of 9 (100%) H. influenzae and M. catarrhalis isolates, respectively, produced beta-lactamase. Bacteriologic eradication was achieved for 118 of 121 (98%) pathogens: 74 of 74 H. influenzae; 34 of 36 (94%) S. pneumoniae; 9 of 9 M. catarrhalis; and 1 of 2 S. pyogenes. Clinical improvement/cure at end of treatment was seen in 103 of 114 (90%) clinically evaluable patients. Clinical recurrence of AOM after completion of therapy occurred in 31 patients. Of the 27 recurrent AOM cases in which tympanocentesis was performed, there were 16 (59%) new infections, 4 (15%) culture-negative results and only 7 (26%) true bacteriologic relapses. Adverse events were recorded in 21 of 160 (13%) patients: vomiting, 16; diarrhea, 3; maculopapular rash, 2. No articular adverse events were recorded. CONCLUSION: Gatifloxacin is efficacious and safe for the treatment of recurrent/nonresponsive AOM.

Acute Disease↗
PubMed2003

Microbiology of otitis media in Costa Rican children, 1999 through 2001.

BACKGROUND: Because of the increasing number of resistant middle ear pathogens and the impact of the new conjugate Streptococcus pneumoniae vaccine, an active surveillance of the microbiology and susceptibility pattern of middle ear pathogens is required. OBJECTIVE: To study the microbiology and susceptibility pattern of middle ear pathogens obtained from Costa Rican children with acute otitis media (AOM), recurrent otitis media (ROM) and therapeutic failure otitis media (FOM). METHODS: Between 1999 and 2001 middle ear fluid (MEF) was collected from 276 Costa Rican patients. S. pneumoniae serotyping and pulsed field gel electrophoresis analysis was done on available strains. RESULTS: Among the total study population, 102 were AOM patients, 98 were ROM patients and 76 were FOM patients. Overall S. pneumoniae (88 strains) was the most common pathogen isolated followed by Haemophilus influenzae (41 strains) and Streptococcus pyogenes (10 strains). H. influenzae was the most common agent in FOM patients (P = 0.015). Beta-lactamase production was observed in 3 of 41 (7%) H. influenzae strains and 3 of 3 (100%) Moraxella catarrhalis strains. Penicillin-nonsusceptible S. pneumoniae strains were more common in FOM (64%) and ROM (63%) patients than in AOM (42%) patients (P = 0.05). S. pneumoniae serotype 19F was the most prevalent serotype, mainly within one distinct clone. CONCLUSIONS: Overall S. pneumoniae serotype 19F was the most common isolate from the middle ear fluid of Costa Rican children. Beta-lactamase-negative H. influenzae was the most prevalent in the subpopulation of patients with FOM. S. pyogenes was the third most common isolate and M. catarrhalis was uncommon.

Acute Disease↗
PubMed2003

Antibiotic-resistant invasive pediatric Streptococcus pneumoniae clones in Israel.

Antibiotic-resistant international clones of Streptococcus pneumoniae are increasingly reported in different parts of the world. We investigated the spread of these clones through an active surveillance performed at the Israeli Streptococcal National Center during 1998 and 1999. Isolates were tested for antibiotic susceptibility, serotyped, and genotyped by random amplified polymorphic DNA analysis and pulsed-field gel electrophoresis. Of 437 isolates, 276 (63.4%) were antibiotic resistant and 156 (35%) were penicillin nonsusceptible (PNS). The PNS isolates were less frequently encountered in southern Israel (27 of 136 [20%]) than in other regions (127 of 301 [42%]). Among 276 antibiotic-resistant isolates, 43 fingerprint patterns were observed. The most common clones were 9V/14-a (19.2%), 5-a (17.8%), and 1-a (10%). The 9V/14-a clone was less common, while the 1-a clone was more frequent in the south than in other regions. The 5-a clone was more common in Jerusalem than in other regions. Among the Jewish and Arab populations the most frequent clones were 9V/14-a (20%) and 1-a (25%), respectively. Three international clones, 9V/14-a-Spain(9V)-3, 6B-a-Spain(6B)-2, and 5-a-Colombia(5)-19, comprised 40% of all antibiotic-resistant isolates and 56% of all PNS isolates. The seven-valent conjugate vaccine covers 58% of the most common clones, all highly PNS clones, and 94% of the multidrug-resistant clones in Israel, while the nine-valent vaccine covers all of them. The most common antibiotic-resistant invasive pediatric S. pneumoniae clones-mainly the three international ones-contribute significantly to increases in antibiotic resistance. Their geographic distribution varies within the country and between the different populations.

Anti-Bacterial Agents↗
PubMed2003

Antibiotic resistance and the potential impact of pneumococcal conjugate vaccines.

Streptococcus pneumoniae is a major cause of morbidity and mortality in young children throughout the world, causing both invasive (meningitis, bacteraemia) and non-invasive (pneumonia, acute otitis media, sinusitis) infections. Over the past few decades, the global emergence of antibiotic-resistant pneumococcal strains has complicated disease management. Thus, healthcare practitioners have begun to place more emphasis on the judicious use of antibiotics and prevention of disease through routine immunisation. Researchers have developed several pneumococcal conjugate vaccines, which due to their technology, are effective in infants and young children. Currently, one 7-valent pneumococcal conjugate vaccine (PNCRM7; Prevenar, Wyeth) is available in various parts of the world and has demonstrated excellent efficacy against vaccine-type invasive disease and efficacy against pneumonia and otitis media caused by the serotypes included in the vaccine. Furthermore, there is evidence suggesting that the use of these conjugate vaccines will reduce the need for antibiotics and the subsequent spread of antibiotic-resistant pneumococci. Ultimately, when routine pneumococcal conjugate vaccination of infants and young children is accompanied by supportive education and active disease surveillance as well as judicious use of antibiotics, there should be a favourable impact on pneumococcal disease incidence in and beyond the vaccinated population.

Anti-Bacterial Agents↗
PubMed2002

Spread of Streptococcus pneumoniae and antibiotic-resistant S. pneumoniae from day-care center attendees to their younger siblings.

A prospective study was conducted to determine the association between pneumococcal carriage among 36 infants and young toddlers cared for at home and carriage among their older siblings who attended 8 day-care centers (DCCs); 71 pneumococcal strains acquired by the younger siblings were compared with those present in the DCCs for 6 months. In 76% of cases, > or =1 strain identical by serotype and antibiogram was isolated in the older siblings' DCC versus 32%-63% in all other DCCs (P<.001). When phenotypically identical strains were compared by pulsed-field gel electrophoresis, the similarity between strains from older siblings' DCCs and the younger siblings' isolates was striking. This was not found when isolates from other DCCs were compared. Vaccinating DCC attendees with a 7-valent pneumococcal conjugate vaccine may play a key role in controlling the spread of antibiotic-resistant pneumococci, because the most resistant serotypes are included in the vaccine.

Anti-Bacterial Agents↗
PubMed2002

Reduction of nasopharyngeal carriage of Streptococcus pneumoniae after administration of a 9-valent pneumococcal conjugate vaccine to toddlers attending day care centers.

A double-blind, randomized study involving 264 toddlers attending day care centers was conducted to document the effect of a 9-valent pneumococcal conjugate vaccine on the carriage rate of pneumococci. Of 3750 cultures done on nasopharyngeal samples obtained from subjects during a 2-year follow-up period after vaccination, 65% were positive for Streptococcus pneumoniae. In all age windows, the rate of carriage of vaccine-type pneumococci was lower among subjects who received the pneumococcal vaccine than among control subjects, because the acquisition rate was lower in the former group. The effect was most pronounced among subjects aged < or =36 months. The sample size enabled us to study protection against carriage of S. pneumoniae serotypes 6B, 9V, 14, 19F, and 23F; significant protection against all serotypes except 19F was seen in the pneumococcal-vaccine group. The rate of carriage of serotype 6A (not included in the vaccine) was also reduced significantly, but the rate of carriage of serotype 19A (not included in the vaccine) was not. The rate of carriage of non-vaccine-type pneumococci (excluding serotype 6A) was higher in the pneumococcal-vaccine group than in the control group.

Carrier State↗
PubMed2002

Increasing incidence of nontyphi Salmonella bacteremia among children living in southern Israel.

OBJECTIVES: To determine if the epidemiology of Salmonella gastroenteritis and childhood bacteremia among the two ethnic populations (Jews and Bedouins) living in southern Israel has changed in recent years. METHODS: Retrospective review of laboratory records and medical charts of patients from whom non-typhi salmonellae were isolated from stool and blood cultures in the 1990-1995 period. RESULTS: The overall incidence of enteric Salmonella infections was 123.5 per 100 000 inhabitants and remained stable during the study period. The incidence of bacteremia among children younger than 4 years increased from 9.3 per 100 000 in the 1990-1992 period to 26.8 per 100 000 in the 1993-1995 period (P 0.01). This increment was especially caused by Salmonella virchow and S. enteritidis, which were also isolated with increasing frequency from stool cultures. The Bedouin population was underrepresented among stool isolates, whereas its representation among blood isolates closely resembled the fraction of this ethnic group in the overall population of the area. CONCLUSIONS: The incidence of enteric salmonellosis has remained stable at a high endemic level in recent years in southern Israel. The incidence of children's bacteremia has experienced a significant increase, associated with S. virchow and S. enteritidis. Differences in the utilization of medical services may explain differences in the epidemiology of Salmonella infections found in the two resident ethnic groups.

Adolescent↗
PubMed2002

Bacterial eradication in the treatment of otitis media.

Drugs differ in their ability to eradicate various pathogens from the middle-ear cavity during acute otitis media (AOM), and these differences clearly affect clinical outcome. Outcome is derived from differences in the association between concentrations of the drugs at the site of infection and the antimicrobial effect (termed pharmacodynamics). These differences are even more marked in the present era of antimicrobial resistance. However, since AOM is a self-limiting disease in most cases, difference in clinical outcome is more difficult to ascertain than that of bacteriological outcome, which is measured within 3-5 days. A favourable clinical outcome regardless of the bacteriological effect of the drug can result in false optimism when less-effective antibiotic drugs are used. Inappropriate study design and manipulation of clinical results add to this confusion. In this review we attempt to highlight the evidence regarding bacteriological response to antibiotics in AOM and to draw attention to potential flaws that may mislead clinicians.

Age Factors↗
PubMed2002

Cytology of middle ear fluid during acute otitis media.

BACKGROUND: Limited information is available on the cellular characteristics of the middle ear fluid (MEF) during acute otitis media (AOM). OBJECTIVES: To determine the white blood cell (WBC) composition of the MEF in AOM before and during antibiotic therapy. MATERIALS AND METHODS: Total WBC and differential counts were determined in the MEF of 96 infants and children (ages 2 weeks to 3 years) with AOM who were receiving antibiotics. WBC counts were reported as number of WBC/mg MEF (mean +/- sd). RESULTS: One hundred forty-five MEF samples were obtained by tympanocentesis at enrollment (Day 1), and 36 samples were collected on Days 4 to 5 after initiation of antibiotic therapy. Sixty-one percent of the patients were <1 year of age, and 38% were receiving antibiotic therapy at enrollment. Twenty-eight MEF samples were paired (same ear, Day 1 and Days 4 to 5). One hundred twelve pathogens were isolated from 95 of 145 (66%) culture-positive samples obtained on Day 1: 67 Haemophilus influenzae, 40 Streptococcus pneumoniae and 5 others. MEF WBC counts were lower on Day 1 in patients who had received previous antibiotic therapy than in those who had not (432.4+/- 412.8 vs. 590.5 +/- 436.8, P = 0.03). WBC counts were higher on Day 1 in culture-positive than in culture-negative samples (603.9 +/- 504.9 vs.421.4 +/- 373.4, P = 0.02). WBC counts were higher on Day 1 in MEF samples positive for S. pneumoniae than in those positive for H. influenzae (799.2 +/- 641.5 vs.506.4 +/- 401.9, P = 0.04). There were no differences in the number of neutrophil WBC present in the samples obtained on Day 1 vs. Days 4 to 5 or between samples positive vs.samples negative for bacterial pathogens. CONCLUSIONS: WBC counts were higher in the MEF of patients with culture-positive AOM than in those with culture-negative AOM and in those with AOM caused by S. pneumoniae.

Acute Disease↗
PubMed2002

Dynamics of pneumococcal nasopharyngeal carriage in children with nonresponsive acute otitis media treated with two regimens of intramuscular ceftriaxone.

BACKGROUND: A 3-day intramuscular ceftriaxone regimen was superior to a 1-day regimen in the treatment of nonresponsive acute otitis media caused by resistant Streptococcus pneumoniae. However, the effect of various regimens of intramuscular cefriaxone on the nasopharyngeal carriage of S. pneumoniae and especially that of resistant strains during and after therapy has not been thoughtfully studied. OBJECTIVES: To compare the effect of one dose and three dose intramuscular ceftriaxone regimens on the nasopharyngeal carriage of S. pneumoniae in patients with nonresponsive acute otitis media treated with these two regimens and to document the dynamics of nasopharyngeal colonization with S. pneumoniae during and after completion of these two therapeutic regimens. PATIENTS AND METHODS: In a prospective study performed during January, 1998, through September, 1999, 170 evaluable patients ages 3 to 36 months with nonresponsive acute otitis media were randomized to receive the 1 (n = 83)- or 3 (n = 87)-day intramuscular ceftriaxone regimen (50 mg/kg/day), respectively. Nasopharyngeal cultures for S. pneumoniae were obtained on Days 1, 4 to 5, 11 to 14 and 28 to 30. Susceptibility of S. pneumoniae to penicillin and ceftriaxone was determined by E-test. RESULTS: On Day 1 nasopharyngeal S. pneumoniae carriage was found in 108 (64%) patients, 54 in each treatment group. Forty-seven of 54 (87%) and 9 of 54 (17%) S. pneumoniae isolates from the one dose group were nonsusceptible to penicillin and ceftriaxone, respectively; the respective values in the three dose group were 49 of 54 (91%) and 8 of 54 (15%). On Days 4 and 5 negative nasopharyngeal cultures were achieved in 43 of 83 (52%) and 70 of 87 (80%) cases from the one dose and three dose group, respectively (P < 0.001). Eradication of penicillin-nonsusceptible S. pneumoniae was achieved on Day 4 to 5 in 18 of 49 (37%) and 39 of 49 (80%) organisms isolated from the one dose and three dose groups, respectively (P < 0.001). Nasopharyngeal S. pneumoniae carriage among evaluable patients on Days 11 to 14 and Days 28 to 30 was 43 of 69 (62%) and 31 of 45 (69%) for the one dose group and 42 of 73 (58%) and 31 of 50 (62%) for the three dose group, respectively (P not significant). A decrease was observed during the study period in the proportion of highly penicillin-resistant S. pneumoniae isolated in the three dose group compared with the one dose group (30, 24, 17 and 13% vs. 30, 27, 19 and 26% at Days 1, 4 to 5, 11 to 14 and 28 to 30, respectively; P = 0.05). CONCLUSIONS: A marked reduction in the carriage of penicillin-nonsusceptible S. pneumoniae (including highly penicillin-resistant organisms) was achieved on Days 4 to 5 of therapy with both ceftriaxone regimens. The 3-day intramuscular ceftriaxone regimen was significantly superior to the 1-day regimen in the reduction of carriage during the treatment period. The reduction of overall S. pneumoniae nasopharyngeal carriage by both ceftriaxone regimens was a short-lived phenomenon followed by rapid recolonization of the nasopharynx.

Acute Disease↗
PubMed2002

Acute otitis media in infants younger than two months of age: microbiology, clinical presentation and therapeutic approach.

BACKGROUND: Information on the causative agents of acute otitis media (AOM) in infants <2 months of age is limited. OBJECTIVES OF THE STUDY: To analyze the etiology, pathogen susceptibility patterns, clinical presentation and frequency of serious bacterial infections in infants <2 months of age with AOM and to determine the relationship between the organisms isolated systemically and those isolated from the middle ear fluid in the patients with serious bacterial infections in the presence of AOM. METHODS: The medical records of 137 infants <2 months of age with AOM who underwent tympanocentesis in the emergency room of Soroka University Medical Center between January 1, 1995, and May 30, 1999, were reviewed. The main variables analyzed included demography, frequency of serious bacterial infections, bacteriologic results, susceptibility patterns of the pathogens and clinical presentation. RESULTS: Median age was 38.7 +/- 13 days; 112 of 137 (82%) infants were hospitalized. Six (4%), 27 (20%), 46 (34%) and 58 (42%) episodes were recorded at age 0 to 2, 3 to 4, 5 to 6 and 7 to 8 weeks, respectively. Fever (temperature >38 degrees C) was present in 96 (70%) of the cases. Culture-negative (bacterial) meningitis was diagnosed in 3 cases. Blood and urine cultures were positive in 1 and 6 infants, respectively. None of the afebrile infants developed serious bacterial infection. One hundred twenty-two bacterial pathogens were isolated from the middle ear fluid of 109 of 137 (80%) patients: Streptococcus pneumoniae in 56 (46%), Haemophilus influenzae in 41 (34%), group A Streptococcus in 12 (10%), enteric gram-negative bacilli in 9 (7%), Moraxella catarrhalis in 3 (2%) and Streptococcus faecalis in 1 (1%). Eleven (20%) of the 56 S. pneumoniae isolates were nonsusceptible to penicillin. Serious bacterial infections were diagnosed in 6 of 137 (4%) patients. Whereas blood and urine grew pathogens typical for blood and urinary tract infections, the middle ear fluid isolates represented different pathogens usually isolated in AOM without any correlation between these 2 groups of pathogens. CONCLUSIONS: (1) Most cases of AOM in infants <2 months of age are caused by pathogens similar to those causing AOM in older children; (2) antibiotic resistance may already be present at early age and should be considered in the empiric treatment of AOM in infants <2 months of age; (3) the presence of AOM does not predict a higher risk for serious bacterial infections in afebrile and febrile infants <2 months of age.

Acute Disease↗
PubMed2002

Multinational study of pneumococcal serotypes causing acute otitis media in children.

BACKGROUND: Streptococcus pneumoniae is a major cause of acute otitis media (AOM) in young children. More than 90 immunologically distinct pneumococcal serotypes have been identified, but limited information is available regarding their relative importance in AOM. METHODS: We analyzed nine existing datasets comprising pneumococcal isolates from middle ear fluid samples collected from 1994 through 2000 from 3,232 children with AOM from Finland, France, Greece, Israel, several East European countries, the US and Argentina. We examined the distribution of pneumococcal serotypes in relation to several demographic and epidemiologic variables, including gender, age, antibiotic resistance and source of culture material. RESULTS: The major serotypes identified included 19F and 23F, each comprising 13 to 25% of pneumococcal middle ear fluid isolates in most datasets; 14 and 6B, comprising 6 to 18%; whereas 6A, 19A and 9V each comprised 5 to 10%. Despite differences in location, study design and antibiotic susceptibility, each major serotype was prominent in most age groups of each dataset. Serotypes represented in the 7-valent pneumococcal conjugate vaccine (PCV-7, 4, 6B, 9V, 14, 18C, 19F, 23F) accounted for 60 to 70% of all pneumococcal isolates in the 6- to 59-month age range, but only 40 to 50% of isolates in children <6 or >/=60 months old. Serotype 3 and, in certain datasets, serotypes 1 and 5, were more important in the <6- and >/=60-month age groups. In each age group vaccine-related serotypes (mainly 6A and 19A) comprised an additional 10 to 15% of all pneumococcal isolates. Four serotypes (23F, 19F, 14 and 6B) accounted for 83% of all penicillin-resistant observations. CONCLUSIONS: This analysis of several geographically diverse datasets indicates that a limited number of serotypes, largely represented in PCV-7, accounted for the majority of episodes of pneumococcal AOM in children between 6 and 59 months of age. Certain serotypes appeared to be relatively more significant in children <6 months or >59 months of age.

Age Factors↗