Nevio Cimolai

Definition and Application of a Histopathological Scoring Scheme for an Animal Model of Acute Mycoplasma pneumoniae Pulmonary Infection

A histopathological scoring system was developed to assess the pathology of acute Mycoplasma pneumoniae pulmonary infection in a hamster model. A final score per animal (ranging 0–26) is obtained by averaging scores from each lung which have been accumulated by the addition of subscores from the assessments of quantity and quality of peribronchiolar and peribronchial infiltrates, luminal exudates, perivascular infiltrates, and parenchymal pneumonia. The scoring scheme was then applied to test the ability of a heat‐killed inoculum to induce pulmonary pathology and to the trial of a 43 kDa protein‐associated antigen as a vaccine immunogen. A heat‐killed inoculum delivered by both intratracheal and intranasal routes did not induce pulmonary pathology compared to a live inoculum (respective mean scores 0.1, 6.7; P<0.01). Animals prevaccinated with the 43 kDa antigen developed an accentuated pathological response after live challenge compared to those unvaccinated (respective mean scores 16.8, 5.8; P=0.00007). Hypersensitization to growth medium components may, however, have contributed to the accentuated disease since the lungs of vaccinated animals challenged with culture‐negative media also were affected (mean score 5.4). Reproducibility of the scoring system was measured by duplicate reading of histology slides which were randomized to the observer upon the second reading (r=0.93; P=0.000009). The scoring system has the ability to differentiate disease severity in small groups of animals.

MRSA and the environment: implications for comprehensive control measures

Environmental contamination with methicillin-resistant Staphylococcus aureus (MRSA) is established soon after colonized or infected patients become resident. There are many studies that detail the mechanisms of spread and environmental survival of methicillin-susceptible Staphylococcus aureus (MSSA); this knowledge translates directly into the same findings for MRSA. The potential ubiquity of MRSA in a health-care setting poses challenges for decontamination. Whereas patients and medical staff are important sources for MRSA spread, the environmental burden may contribute significantly in various contexts. Effective control measures must therefore include consideration for MRSA in the environment.

Hemolytic-uremic syndrome associated with acute Campylobacter upsaliensis gastroenteritis.

Dr. J.E. Carter, Department of Pediatrics, British Columbia’s Children’s Hospital, 4480 Oak Street, Vancouver, BC V6H 3V4 (Canada) Dear Sir, The majority of the patients with gastroenteritis-associated hemolytic-uremic syndrome (HUS) appear to have been infected with verotoxigenic Escherichiα coli. Other uncommonly cited infectious etiologic agents have also been associated with the evolution of HUS, and among these reports, campylobacters have been implicated as the cause of preceding gastroenteritis. We detail the first association of Campylobacter upsa-liensis with HUS and describe our investigations which provide evidence against the possibility of a coinfection with verotoxigenic E. coli. Five days prior to arriving at our hospital, a 14-year-old female suffered from an acute onset of periumbilical crampy abdominal pain. By the next day, she developed profuse watery diarrhea. Because of the severity of the illness, she was investigated and found to have microscopic hematuria, thrombocy-topenia(100 × 109/1), and renal dysfunction (creatinine 120μmol/l, urea 10.2mmol/l). She was transferred the following day because of progressive thrombocytopenia (45 × 109/1). She was initially managed expectantly, but by the 3rd hospital day, progressive illness was evident: hemoglobin 84 g/l, platelets 92 × 109, creatinine 796 μmol/l, and urea 30.5 mmol/l. A renal ultrasound revealed a moderate amount of peritoneal fluid and increased echogenicity of the renal cortex. A stool specimen yielded a Campylobacter species. A peritoneal dialysis catheter was inserted. A renal biopsy specimen demonstrated evidence of thrombotic microan-giopathy in early organization, consistent with HUS. The diarrheal episode resolved within 2 days of admission, and, therefore, antibiotics were not specifically prescribed for the campylobacteriosis. Dialysis was continued for 1 week. The clinical course was uneventful, and the patient was discharged after a total of 3 weeks at which time her laboratory investigations included: white blood cell count 5.7 × 109/1, hemoglobin 78 g/l, platelets 181 × 109/1, creatinine 211 μmol/l. The stool isolate was subsequently identified as C. upsaliensis. Blood cultures were specifically subcultured to assess Campylobacter growth, and none was found. Sorbitolnegative E. coli were not found. A negative microneutralization assay for free fecal verotoxin was obtained on a stool specimen which had been acquired 5 days into the course of illness when symptomatic diarrhea was still evident. In addition, a random screening of stool coliforms was performed for evidence of verotoxin virulence genes. By the polymerase chain

IgA nephropathy associated with Campylobacter jejuni enteritis

A patient who developed IgA nephropathy after the onset of Campylobacter jejuni enteritis is discussed.

Branhamella catarrhalis bacteremia in children.

ABSTRACT. Two cases of Branhamella catarrhalis bacteremia in childhood are presented. The literature is reviewed for this unusual cause of bacteremia.

The cranberry and the urinary tract

Cranberry products have been heralded as natural treatments for urinary tract infections (UTIs) and have been widely used for this purpose. Current evidence favours an antibacterial role for the cranberry’s natural polyphenols or tannins. Although limited species- and strain-specific direct inhibition has been determined in vitro, it has been suggested that a key mechanism of inhibition, especially for the abundant uropathogenic E. coli, relies on anti-adhesion properties. Many studies of prevention have been complicated due to the enrollment of patients who have had complicated urinary tracts, and outcomes have not been consistently favourable. In contrast, significant prevention has been shown for acute cystitis among high-risk young females. While reasonably well tolerated and deplete from side effects, further scientific work is required to better place the role of cranberry products in the management of UTIs. Progress in this area has set the stage for further hypothesis testing studies.

Beta-haemolytic non-group A streptococci and pharyngitis: A case-control study

A case-control study was conducted to examine the association of beta-haemolytic non-group A streptococci and pharyngitis in a paediatric population (n=502). No association could be found between disease and traditional Lancefield groups B, C, F, or G. When the analysis included the clustering of genetically related subgroups from different Lancefield groups, an association was evident for moderate and heavy quantitations of beta-haemolytic “large colony” group C and G streptococci (Streptococcus equisimilis and human biotypes of large colony group G streptococci) (p=0.021). This study further defines a subset of the beta-haemolytic non-group A streptococci that merit recognition by both the laboratory and physician.

The role of healthcare personnel in the maintenance and spread of methicillin-resistant Staphylococcus aureus

Healthcare workers may acquire methicillin-resistant Staphylococcus aureus (MRSA) from patients, both hospital and home environments, other healthcare workers, family and public acquaintances, and pets. There is a consensus of case reports and series which now strongly support the role for MRSA-carrying healthcare personnel to serve as a reservoir and as a vehicle of spread within healthcare settings. Carriage may occur at a number of body sites and for short, intermediate, and long terms. A number of approaches have been taken to interrupt the linkage of staff-patient spread, but most emphasis has been placed on handwashing and the treatment of staff MRSA carriers. The importance of healthcare workers in transmission has been viewed with varying degrees of interest, and several logistical problems have arisen when healthcare worker screening is brought to the forefront. There is now considerable support for the screening and treatment of healthcare workers, but it is suggested that the intensity of any such approach must consider available resources, the nature of the outbreak, and the strength of epidemiological associations. The task of assessing healthcare personnel carriage in any context should be shaped with due regard to national and international guidelines, should be honed and practiced according to local needs and experience, and must be patient-oriented.

Rapid immunoblot method for diagnosis of acuteMycoplasma pneumoniae infection

A rapid immunoblotting technique based on the IgM response to a major immunogenic protein is described for the diagnosis ofMycoplasma pneumoniae infection. Using results of the complement fixation test as the criterion for diagnosis, the rapid immunoblot method was positive in 95.7 % of patients. The sensitivity was reduced to 81.9 % if the test was performed on either single sera or acute sera only from serum pairs. Although the few sera that failed to demonstrate a positive IgM response were more likely to be from older patients, there was a consistent IgM response recorded for both younger (<20 years) and older (≥20 years) patients.

Bacterial genotype and neurological complications of Escherichia coli O157:H7‐associated haemolytic uraemic syndrome

We examined the possibility of an association between the bacterial genotype ofEscherichia coli O157:H7 and the likelihood of progression to neurological complications in childhood gastroenteritis‐associated haemolytic uraemic syndrome (D+HUS). Bacterial stool isolates were available from 51 patients with HUS; 11 of these patients suffered a neurological complication. Bacteria were assessed for plasmid content, verotoxin (Shiga‐like toxin) profile, verotoxin 2 subtype, and presence of the eaeA (effacement and attachment) marker. No association of bacterial genotype with central nervous system (CNS) manifestations was observed. Whilst the cause of CNS manifestions may be multifactorial, there is no evidence at present to implicate specific bacterial traits.