Acute monoarthritis in young children: comparing the characteristics of patients with juvenile idiopathic arthritis versus septic and undifferentiated arthritis.

Acute arthritis is a common cause of consultation in pediatric emergency wards. Arthritis can be caused by juvenile idiopathic arthritis (JIA), septic (SA) or remain undetermined (UA). In young children, SA is mainly caused by Kingella kingae (KK), a hard to grow bacteria leading generally to a mild clinical and biological form of SA. An early accurate diagnosis between KK-SA and early-onset JIA is essential to provide appropriate treatment and follow-up. The aim of this work was to compare clinical and biological characteristics, length of hospital stays, duration of intravenous (IV) antibiotics exposure and use of invasive surgical management of patients under 6 years of age hospitalized for acute monoarthritis with a final diagnosis of JIA, SA or UA. We retrospectively analyzed data from < 6-year-old children, hospitalized at a French tertiary center for acute mono-arthritis, who underwent a joint aspiration. Non-parametric tests were performed to compare children with JIA, SA or UA. Bonferroni correction for multiple comparisons was applied with threshold for significance at 0.025. Among the 196 included patients, 110 (56.1%) had SA, 20 (10.2%) had JIA and 66 (33.7%) had UA. Patients with JIA were older when compared to SA (2.7 years [1.8-3.6] versus 1.4 [1.1-2.1], p < 0.001). Presence of fever was not different between JIA and SA or UA. White blood cells in serum were lower in JIA (11.2 × 109/L [10-13.6]) when compared to SA (13.2 × 109/L [11-16.6]), p = 0.01. In synovial fluid leucocytes were higher in SA 105.5 × 103 cells/mm3 [46-211] compared to JIA and UA (42 × 103 cells/mm3 [6.4-59.2] and 7.29 × 103 cells/mm3 [2.1-72] respectively), p < 0.001. Intravenous antibiotics were administered to 95% of children with JIA, 100% of patients with SA, and 95.4% of UA. Arthrotomy-lavage was performed in 66.7% of patients with JIA, 79.6% of patients with SA, and 71.1% of patients with UA. In children less than 6 years of age with acute mono-arthritis, the clinical and biological parameters currently used do not reliably differentiate between JIA, AS and UA. JIA subgroups that present a diagnostic problem at the onset of monoarthritis before the age of 6 years, are oligoarticular JIA and systemic JIA with hip arthritis. The development of new biomarkers will be required to distinguish JIA and AS caused by Kingella kingae in these patients.

Inflammatory markers limitations in the diagnosis of pediatric calcaneal osteomyelitis.

Calcaneal osteomyelitis is an uncommon, but clinically important emergent condition in the differential of the limping child. Early recognition is paramount to prevent complications from delayed diagnosis like formation of periosteal abscesses or growth plate injury. The diagnosis of pediatric osteoarticular infection relies on a combination of clinical exam, imaging and inflammatory markers. Erythrocyte sedation rate (ESR) and C-reactive protein (CRP) have reported sensitivities for osteomyelitis of 94% and 95%, respectively. However, clinicians should be aware that certain clinical factors can decrease the reliability of inflammatory markers in this pediatric condition. Location of infection in small bones like the calcaneus can lead to significantly lower sensitivities than in long bones. Pretreatment with antibiotics prior presentation can also decrease the reliability of ESR and CRP. In this case, we highlight two unique clinical factors that diminish the sensitivity of commonly used inflammatory markers in the diagnosis of pediatric osteomyelitis.

[Septic arthritis in children with normal initial C-reactive protein: clinical and biological features]. / Arthrite septique de l'enfant à protéine C-réactive initialement normale : description clinique et biologique.

Septic arthritis has to be suspected in children with joint effusion and fever so as to perform joint aspiration, which will confirm the diagnosis by bacteriological methods, and to perform surgical treatment by joint lavage. Since development of current molecular methods, such as real-time PCR, Kingella kingae has become the first microbial agent of osteoarticular infections in young children, whereas Staphylococcus aureus is second. C-reactive protein (CRP) is an aid used to diagnose septic arthritis, but its elevation could be moderate. In a previous study, conducted at our hospital, 10% of children hospitalized for S. aureus or K. kingae septic arthritis had a CRP level<10 mg/L. To determine if diagnosis of septic arthritis could be made by other parameters, we analyzed the clinical and biologic features of these patients and compared them to those of children hospitalized for septic arthritis with initial CRP ≥10 mg/L. Among the 89 children with septic arthritis, 10% (n=9) had initial CRP<10 mg/L (K. kingae, n=5/63 ; S. aureus, n=4/26). Initial temperature and fibrinogen were significantly lower in the CRP<10 mg/L group than in the other (37.3°C vs. 37.9°C, P=0.039 and 4.19 vs. 5.72 g/L, P=0.003, respectively). Age, symptom duration before diagnosis, as well as leukocyte and platelet counts were similar in both groups. Two children (2/89=2.2%) with S. aureus septic arthritis had no fever, CRP elevation, or fibrinogen elevation. In the CRP-negative group, three of four children with S. aureus arthritis and one of five with K. kingae arthritis had a high CRP level (34, 40, 61, and 13 mg/L, respectively) 3 days after surgery and antibiotic treatment. One child with K. kingae septic arthritis and initial CRP<10 mg/L needed a second surgical drainage because of relapse of arthritis. In the S. aureus arthritis group, none of the children with initial CRP<10 mg/L experienced complications, while six of those with initial CRP≥10 mg/L needed a second surgical act or hospitalization in an intensive care unit. While CRP is most often>10 mg/L during septic arthritis in children, it could be negative in up to 20% of patients in different studies. However, a mild inflammatory syndrome or even a CRP<10 mg/L cannot exclude diagnosis of septic arthritis. Therefore, a first episode of monoarthritis in children has to be considered as septic arthritis and treatment should not be delayed.

Kingella kingae infections in children.

Kingella kingae is a beta-hemolytic gram-negative bacillus. It was first described in the 1960's by EO King and has been reported as a cause of osteo-articular pediatric infections since the early 1980's. We performed a retrospective review of all pediatric cases of invasive K. kingae infection between 1997 and 2002, in order to define the incidence, clinical presentation and outcome of invasive K. kingae infections in a pediatric population. During the study period, a total of 24 pediatric patients with K. kingae infection were identified. There were 15 blood culture isolates of K. kingae, out of a total of 1151 (1.3%) positive blood cultures, and 9 synovial fluid culture isolates out of a total of 76 (11.8%) positive synovial fluids. Fifteen patients had osteo-articular infections and 9 had primary bacteremia without osteo-articular infection. Outcome was favorable in all cases and only in 2 patients with knee joint infection was surgical intervention performed, by means of formal knee arthrotomy. All patients recovered uneventfully, in 7 cases without any intervention and in the others with intravenous or oral antibiotic. In conclusion, invasive K. kingae infection is not uncommon in Israel. It usually has a mild course and thus is not always detected and treated. As K. kingae grows best in blood culture broth, blood and joint fluid should always be inoculated into blood culture bottles in suspected cases. This bacterium is highly sensitive to betalactame antibiotics and infection resolves quickly with antibiotic treatment. Surgical intervention for osteo-articular infection is seldom indicated.

Bacterial protein microarrays for identification of new potential diagnostic markers for Neisseria meningitidis infections.

Neisseria meningitidis is the most common cause of meningitis and causes epidemic outbreaks. One trait of N. meningitidis, which is associated with most of the currently recognized virulence determinants, is the presence of phase-variable genes that are suspected to enhance its ability to cause an invasive disease. To detect the immune responses to phase-variable expressed proteins, we applied protein microarray technology for the screening of meningitis patient sera. We amplified all 102 known phase-variable genes from N. meningitidis serogroup B strain MC58 by polymerase chain reaction and subcloned them for expression in Escherichia coli. With this approach, we were able to express and purify 67 recombinant proteins representing 66% of the annotated genes. These were spotted robotically onto coated glass slides to generate protein microarrays, which were screened using 20 sera of patients suffering from meningitis, as well as healthy controls. From these screening experiments, 47 proteins emerged as immunogenic, exhibiting a variable degree of seroreactivity with some of the patient sera. Nine proteins elicited an immune response in more than three patients, with one of them, the phase-variable opacity protein OpaV (NMB0442), showing responses in 11 patient sera. This is the first time that protein microarray technology has been applied for the investigation of genetic phase variation in pathogens. The identification of disease-specific proteins is a significant target in biomedical research, as such proteins may have medical, diagnostic, and commercial potential as disease markers.

[The diagnostic specificity of the antigen-binding lymphocyte test in Neisseria-induced infections].

Neisseria-induce different infections, but many representatives of this genus are saprophytes. In this connection it is important to evaluate the species, and for N. meningitidis also group specificity of the immunological diagnostics of meningococcal infection and gonorrhea. In this work the specificity of the antigen-binding lymphocyte test was studied in experiments with the immunization of rabbits and the examination of patients. In the tests of indirect rosette-formation and its inhibition the role of antigenic relationships between different pathogenic and nonpathogenic Neisseria was excluded and the species and group specificity of our Neisseria immunoreagents, used in the diagnostics of meningococcal infection and gonorrhea, was proved.

Immune response to invasive Kingella kingae infections, age-related incidence of disease, and levels of antibody to outer-membrane proteins.

The immune response to Kingella kingae was determined by enzyme-linked immunosorbent assay, using outer-membrane proteins as coating antigen, in 19 children with invasive infection. The age-related incidence of K. kingae disease in southern Israel during 1988-2002 was calculated and correlated with serum antibody levels in healthy children. Significant increases in immunoglobulin G (IgG) levels were found in children convalescing after invasive infections. The incidence was 1.3, 40.3, 23.9, 5.7, and 1.9 cases/100,000 children among those aged 0-5, 6-11, 12-23, 24-35, and 36-47 months, respectively. A low attack rate and undetectable serum IgA and high IgG levels were found during the first 6 months of life, which indicates that protection was conferred by maternally derived immunity. The high attack rate found among 6-24-month-old children coincides with the age at which antibody levels were lowest. Low incidence of disease and increasing antibody levels were found among older children, which probably represents cumulative experience with K. kingae antigens via colonization or infection.

Interrelationship between the pharmacokinetics and pharmacodynamics of cefaclor advanced formulation in patients with acute exacerbation of chronic bronchitis.

Cefaclor advanced formulation (cefaclor AF) is an extended-release form of the oral cephalosporin cefaclor. When cefaclor AF 750 mg twice-daily and cefaclor immediate release 500 mg three-times-a-day are compared there is a skew to the right of the pharmacokinetic profile and higher levels are achieved. Based on this pharmacokinetic finding, we examined the relationship between the bacterial susceptibility to cefaclor (MIC), the achieved cefaclor AF serum and sputum concentrations, and in vivo eradication of the bacteria in 36 patients with acute exacerbations of chronic bronchitis. The mean peak concentrations in serum and sputum 5 h after administration were 8.6 microg/ml (95% CI: 8.1 microg/ml - 9.1 microg/ml) and 1.5 microg/ml (95% CI: 1.4 microg/ml - 1.7 microg/ml), respectively. Cefaclor was always detectable 8 h after administration. At post therapy, treatment was successful in 31 (86.1%) patients. Cefaclor concentrations in serum persisted above the MIC for more than 40% of dosing interval in 31 subjects, and those in sputum in 24 patients. Treatment was successful in all subjects with percent of time above the MIC in serum of >40%, whereas the time that levels in sputum stayed above the MIC was not the pharmacodynamic parameter that correlated best with therapeutic efficacy for cefaclor. Our data demonstrate that when cefaclor AF is dosed twice-daily, the in vivo pharmacodynamic susceptibility breakpoint is 8 microg/ml. The good activity and pharmacokinetics of cefaclor AF provide serum concentrations higher than the MIC of Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis for more than 40% of the validated dosing interval. Therefore, it might be considered for first choice treatment of acute exacerbations of chronic bronchitis.

A pharmacodynamic model to support a 12-hour dosing interval for amoxicillin/sulbactam, a novel oral combination, in the treatment of community-acquired lower respiratory tract infections.

We evaluated, by time-kill studies, the pharmacodynamics of amoxicillin/sulbactam (AMX/SUL, 875 mg/125 mg), a novel oral combination, against the major respiratory pathogens in 12 volunteers receiving a single dose. The sera corresponding to 50% of a 12-h dosing interval displayed either bactericidal or inhibitory activity against both a penicillin-susceptible and a penicillin-intermediate Streptococcus pneumoniae strain (penicillin MIC of 0.03 and 0.25 microg/ml, respectively), as well as against a beta-lactamase-positive Moraxella catarrhalis and a beta-lactamase-negative Haemophilus influenzae strain. Both the peak samples and those corresponding to 4 h after dose (i.e. 33% of a 12-h dosing interval) proved active against both a penicillin-resistant S. pneumoniae (MIC, 2 microg/ml) and a beta-lactamase-positive H. influenzae strain. The AMX-SUL formulation evaluated in this study showed pharmacodynamic features that support clinical trials to assess its efficacy in the treatment of lower respiratory tract infections with a 12-h dosing interval regimen.

Immune response to surface protein A of Streptococcus pneumoniae and to high-molecular-weight outer membrane protein A of Moraxella catarrhalis in children with acute otitis media.

The immune response was evaluated in 11 children with Streptococcus pneumoniae and in 9 children with Moraxella catarrhalis otitis media. The age of the children had a range of 4-32 months. The mean IgG, IgM, and IgA antibody responses to surface protein A (PspA) of S. pneumoniae in sera from children at the acute and convalescent stages were 4864 versus 5831 ng/mL, P<.05, 1075 versus 3752 ng/mL, P<.05, and 67 versus 93 ng/mL, nonsignificant (NS), respectively. The mean IgG, IgM, and IgA antibody responses to the high-molecular-weight outer membrane protein (UspA) of M. catarrhalis in sera from children at acute and convalescent stages were 710 versus 935 mg/mL, NS; 1895 versus 2646 ng/mL, NS; and 121 versus 204 ng/mL, P<.05, respectively. These data show that PspA and UspA are immunogenic in children after otitis media.

Analysis of antigenic structure and human immune response to outer membrane protein CD of Moraxella catarrhalis.

Moraxella catarrhalis is an important cause of otitis media in children and lower respiratory tract infections in adults with chronic obstructive pulmonary disease (COPD). Outer membrane protein CD (OMP CD) is a 45-kDa protein which is a potential vaccine antigen to prevent infections caused by M. catarrhalis. Eight monoclonal antibodies were used to study the antigenic structure of the OMP CD molecule by assaying recombinant peptides corresponding to the sequence of the protein. This approach identified two surface-exposed epitopes, including one near the amino terminus (amino acids 25 to 44) and one in the central region of the molecule (amino acids 261 to 331). Assays with serum and sputum supernatants of adults with COPD revealed variable levels of antibodies to OMP CD among individuals. To determine which portions of the OMP CD molecule were recognized by human antibodies, three human serum samples were studied with six recombinant peptides which span the sequence of OMP CD. All three sera contained immunoglobulin G antibodies which recognized exclusively the peptide corresponding to amino acids 203 to 260 by immunoblot assay. Adsorption experiments with whole bacteria established that some of the human antibodies are directed at surface-exposed epitopes on OMP CD. We conclude that OMP CD is a highly conserved molecule which contains at least two separate epitopes which are exposed on the bacterial surface. While individual adults with COPD show variability in the immune response to OMP CD, a specific region of the OMP CD molecule (amino acids 203 to 260) is important as a target of the human immune response.

Human antibody response to Moraxella catarrhalis antigens.

Moraxella catarrhalis was isolated from 68 of 200 (34%) sputum and 56 (28%) nasopharyngeal swab samples of patients with community-acquired pneumonia. Of the 68 pneumonia patients, 42 (61.8%) were males and 26 (38.2%) females. Fifty one of the 68 patients (75%) had chronic underlying diseases. beta-lactamase was produced by 37 (54.4%) of the 68 sputum samples and 32(57.1%) of the 56 nasopharyngeal isolates. In an ELISA using outer membrane protein antigens of M. catarrhalis against patient sera showed 40 of 68 (58.8%), and 43 of 68 (63.2%) significant increase in convalescent to acute sera when IgA, IgM and IgG3 were used respectively. In control sera only of 30(3.3%) and none showed significant antibody rise when IgA, IgM and IgG3 conjugates were used respectively (P < 0.05).

Human immune response against outer membrane proteins of Moraxella (Branhamella) catarrhalis determined by immunoblotting and enzyme immunoassay.

The role of Moraxella (Branhamella) catarrhalis as a respiratory tract pathogen is increasingly recognized. We looked at the human immune response against individual outer membrane proteins of M. catarrhalis and against the 81-kDa CopB protein, which has previously been shown to be a target for protective antibodies. Paired serum samples from six elderly patients with pneumonia were tested by Western blot (immunoblot) analysis by using outer membrane vesicles of M. catarrhalis 035E as antigen. All of the six convalescent-phase serum samples reacted with a protein which migrated at the position of the CopB protein and with a high-molecular-weight protein of M. catarrhalis; three serum samples also reacted with a 34-kDa outer membrane protein. Paired serum samples from 18 patients, 10 of which had M. catarrhalis infection on the basis of previous serology results, were tested by enzyme immunoassay (EIA) with the CopB protein and whole cells of M. catarrhalis 035E as antigens. Nine patients showed a significant rise in EIA titer between acute- and convalescent-phase sera when whole bacterial cells were used as antigens. Six (67%) patient samples that were positive by the EIA with the whole-cell antigen were also positive by the EIA with the CopB antigen, and six of nine patient samples negative by the EIA with the whole-cell antigen were also negative by the EIA with the CopB antigen. These results suggest that both the CopB and a high-molecular-weight protein are major targets of the immune response against M. catarrhalis, and further studies with greater amounts of patient materials are needed to elucidate the usefulness of CopB as an antigen in etiologic studies.

The efficacy of mezlocillin-amikacin combination in febrile neutropenic children with oncologic disease.

The efficacy of mexlocillin-amikacin combination as empirical therapy for febrile neutropenic patients was studied in 30 children (21 males, 9 females) with various oncologic diseases aged 1-15 years (mean age 7.3 +/- 4.4) in the Istanbul Medical School, Oncologic Disease Research and Treatment Center, and Department of Pediatric Hematology-Oncology between January 1 and May 31, 1988. The response rate was 76.6%. Profound persistent granulocytopenia (fewer than 100 ml) was present in 70% of the patients. In 63.3% of patients, the infections were microbiologically documented (60%) Gram(+) and 40% Gram(-). The combination was well tolerated with hepatic and/or renal disturbances in 8 cases (26.6%). We conclude that mezlocillin-amikacin is an effective empirical combination in the initial treatment of infections in febrile neutropenic children with various oncologic diseases.