Abscess

Mice were killed when symptoms of clinical disease (significant weight loss or diarrhea) became apparent in control groups, usually around 8 weeks after initiation of experiments. Samples of proximal colon, mid-colon, and distal colon were immediately fixed in buffered 10% formalin. Four to five microns of paraffin-embedded sections were stained with hematoxylin and eosin, and inflammation was assessed with a modified version of a previously described scoring system (Read et al., 2000 (link)). Each sample was graded semiquantitatively from 0 to 3 for the four following criteria: degree of epithelial hyperplasia and goblet cell depletion; leukocyte infiltration in the lamina propria; area of tissue affected; and the presence of markers of severe inflammation such as crypt abscesses, submucosal inflammation, and ulcers. Scores for each criterion were added to give an overall inflammation score for each sample of 0–12. The total colonic score was calculated as the average of the individual scores from the sections of proximal colon, mid-colon, and distal colon. In the graphs shown, each point corresponds to an individual mouse. Micrographs show sections of mid-colon.

The study definitions reflected national guidelines for management of uncomplicated malaria, which were valid at the time of the study [11 (link)]. In summary, the guidelines recommend that in high malaria risk areas, all children under five years of age with fever or history of fever should be presumptively treated with AL. In low malaria risk areas, presumptive treatment with AL is recommended in all febrile children in the absence of measles, runny nose and other obvious causes of fever. For clinical management purposes, all parts of Kenya were classified as high malaria risk areas, except the highlands of Central and Nairobi provinces. In patients aged five years and older and regardless of the malaria risk, all febrile patients in the absence of another obvious cause of fever should be tested for malaria (microscopy or RDT) and only test positive patients should be treated with AL. In the same age group, presumptive AL treatment is recommended in absence of malaria diagnostics.
Therefore, to reflect criteria for testing and AL treatment, all analyses were restricted to febrile, non-pregnant patients weighing 5 kg and above, presenting for an initial outpatient visit without being referred or admitted for hospitalization. Patients aged five years and older presenting with another obvious cause of fever, as well as the children less than five years of age meeting the same criteria in low risk areas, were excluded from the analysis. Another obvious cause of fever was defined as febrile patients presenting concomitantly with runny nose, sore throat, oral thrush, wounds, urinary problem, skin problem or abscesses. Fever was defined as axillary temperature of ≥37.5°C or a history of fever during the present illness.
To ensure comparable evaluation of anti-malarial treatment practices based on different age-specific recommendations for malaria diagnosis, the focus of the analysis was observations from health facilities where AL was in stock during the survey, stratified by the availability of diagnostics and patients' age (under five and over five years of age). At facilities with malaria diagnostics, anti-malarial treatment practices were further stratified by the use of malaria diagnostic tests and the patient's test result. Combined microscopy and RDT results are presented since the small number of patients with malaria RDTs precluded a meaningful analysis stratified by type of diagnostics.
Data entry and management was undertaken using Access (Microsoft, USA), through customized data entry screens with in-built range and consistency checks. All forms were entered twice by independent data entry clerks and data files were compared for errors using a verification programme and referring to original questionnaires. All analyses were performed using STATA, version 11. The precision of proportions (95% confidence interval [CI]) was determined adjusting for the cluster sampling at the health facility level.

All consecutive patients aged 3 months to 18 years old with a diagnosis of acute OM and/or SA according to the International Classification of Diseases, 9th Revision, Clinical Modification code were evaluated for inclusion. A case was defined by diagnosis of OM or SA on imaging, preferably magnetic resonance imaging (MRI, gold standard) for OM, or in alternative computed tomography (CT scan), Tc99 bone scintiscan, PET-TC scan, or ultrasound (US)/MRI for SA. Long bones were considered the typical site of infection for OM. The hips were considered a high-risk site for both OM and SA. Exclusion criteria were diagnosis of immunodeficiency or hemoglobinopathy or chronic granulomatous disease, immunosuppressive therapy, concomitant systemic bacterial infection, and ongoing antibiotic treatment on admission. Patients with complicated infections, not fully vaccinated, and/or with incomplete follow-up were excluded, as well as those with chronic osteomyelitis and Brodie's abscess.
The population was divided into two main groups, OM and SA. Each group was further divided into three groups: pre-intervention, post-intervention not following the guidelines (no GL), and post-intervention group with adherence to the guidelines (GL).
The following variables, selected a priori, were evaluated: age, sex, weight, fever, vaccination status, white blood cells, and neutrophil count, CRP, erythrocyte sedimentation rate (ESR), and procalcitonin (PCT) at onset, IV and oral antibiotic treatment with duration, diagnosis and imaging type, typical vs. atypical site, results of blood, pus, synovial fluid cultures, MRSA colonization status, Quantiferon results, PVL test positivity, treatment failure (defined as treatment escalation to broad spectrum antibiotics and/or need for surgery) and relapse at six months of follow-up. PCR tests for identification of K. kingae or other pathogens in case of culture-negative infections were not performed, as not included as standard of care at our facility.

Superficial infections were defined by erythema, wound drainage, suture abscesses, and excessive warmth at the surgical site. Superficial wound dehiscence without any clinical signs of infection were not counted as infected, and if antibiotics were given, these patients were categorized as prophylactic antibiotics. Deep infections were delineated as those who required a return to the operating room for irrigation and débridement.