False penicillin resistance in Neisseria meningitidis following direct susceptibility tests from blood cultures.

Blood cultures drawn from a patient with clinically diagnosed invasive meningococcal disease, who had been previously administered benzylpenicillin, had beta-lactamases added to increase the probability of recovery of the causative organism. The blood cultures subsequently yielded Neisseria meningitidis but direct susceptibility tests by the comparative disk diffusion method demonstrated greatly reduced zones of inhibition to penicillin (1 unit disk). Repeat testing from subcultures showed full penicillin sensitivity. Inoculation of blood culture bottles with a variety of penicillin sensitive bacteria with the addition of beta-lactamases showed the same effect of false penicillin resistance, owing to carry over of sufficient beta-lactamase from blood culture bottles during inoculation of direct susceptibility plates to inactivate the penicillin in the disks. Direct susceptibility tests to beta-lactam agents should not be carried out on positive blood cultures to which beta-lactamases have been added.

Streptococcal toxic shock syndrome: a description of 14 cases from North Yorkshire, UK.

OBJECTIVE: To analyze the clinical and laboratory features of patients diagnosed with streptococcal toxic shock syndrome (TSS) in North Yorkshire from 1986 to 1999. METHODS: Records of patients with features satisfying the published criteria for streptococcal TSS were reviewed from laboratory and clinical records made at the time and from the hospital case notes. Isolates of streptococci were analyzed for serotype and genes encoding for the production of streptococcal pyrogenic exotoxins. RESULTS: Fourteen patients satisfied the entry criteria. In one district, where the data were complete, the annual incidence of detected streptococcal TSS rose from 1.1 to 9.5 cases per million population in the 1990s. TSS was associated with various M serotypes of group A streptococci and various exotoxin genotypes. Two cases (14% of the series) were associated with severe group G streptococcal infection. The fatality rate was 64%, and the mode of time to death was 4 days. Local tissue necrosis occurred in 71% of cases, including necrotizing fasciitis, intrathoracic and intra-abdominal forms. Non-steroidal anti-inflammatory drugs (NSAIDs) had been taken around the time of onset of disease by 92% of the patients with TSS. CONCLUSIONS: There has been a dramatic increase in the number of detected cases of streptococcal TSS over the 14 years since the first case was recognized here. There was a wide range of invasive forms of infection, a high fatality rate even in fit young adults, and a rapid course from onset to death. There was a high association of TSS with aggressive streptococcal infection producing local tissue necrosis.

Problems with the decontamination of dental handpieces and other intra-oral dental equipment in hospitals.

Dental departments within district general hospitals contain items of equipment that require decontamination between patients. Some of these items are complex and expensive, and in busy clinics, may be required in large numbers if a sterile services department (SSD) were to be used. This may result in local manual cleaning of these instruments and sterilization in non-vacuum downward displacement autoclaves within dental departments, despite some items having narrow lumens, deep recesses and cavities, which will not adequately sterilize these instruments. Infection control teams should be aware of these difficulties particularly when arranging satisfactory infection control and decontamination procedures in hospital dental departments.

Protective over-shoes are unnecessary in a day surgery unit.

The lack of agreement on the use of over-shoes tends to perpetuate the ritual of their use in general operating theatres. However, the limited evidence which supports their use in such settings is not applicable in a Day Surgery Unit where their use is not recommended. In order to reduce overt contamination in the unit theatre, a local protocol should be drawn up specifying the use of designated day unit footwear for those that remain within the unit and for all persons entering the operating theatre.

Nosocomial Escherichia coli O157 infection.

Nosocomial transmission of Shiga toxin-producing Escherichia coli O157 to two patients and three nurses is described. The index case presented with rectal bleeding rather than diarrhoea, and additional infection control measures were therefore only instituted after detection of the organism. Of the nurses, two were asymptomatic and detected on a screening programme of all staff in contact with the affected patients. Two patients died, one from Clostridium perfringens bacteraemia. The use by staff of full protective gowns for handling patients from their first onset of diarrhoea is recommended, rather than plastic aprons. Interest from the media was intense, despite the small number of patients and staff affected, and early preparations for media enquiries should be made in such episodes.

Bacteraemic Streptococcus pyogenes infection in the peri-partum period: now a rare disease and prior carriage by the patient may be important.

OBJECTIVES: To describe the features of invasive peri-partum Streptococcus pyogenes infection as it occurs in current day practice in North Yorkshire. METHODS: The case and laboratory records of all mothers and/or babies with detected S. pyogenes bacteraemia in the Harrogate and Northallerton districts of North Yorkshire (combined catchment population 260 000) were reviewed for the 20 years 1980-99. An additional bacteraemic case occurring recently in the York district was included. RESULTS: In six recorded episodes, both mother and baby were affected in three, mother only in two and baby only in one. The incidence of detected infection was one such episode per million population per year, one episode per 11 000 live births and one infected baby per 18 000 live births. Maternal features included endometritis, septicaemia, peritonitis, necrotising fasciitis and toxic shock syndrome while, in babies, infection was manifest by stillbirth or septicaemia, cyanosis, jaundice, lethargy and cellulitis. CONCLUSION: Peri-partum S. pyogenes infection is rare in North Yorkshire, with a local incidence revealed in this study of 1/million population/year, or 1:11 000 live births. Invasive neonatal infection with S. pyogenes appears to be six times less frequent in this locality than with group B streptococci. Mothers and/or their babies can be affected. Data suggests that some infection is autogenous from streptococci carried in the mother's genital tract. Although data in this setting are currently few, when a mother has suspected invasive group A streptococcal infection we recommend that the newborn child should also receive antibiotics without delay.

Incidence and outcome of pneumococcal meningitis in northern England.

Since pneumococcal meningitis continues to have high mortality and morbidity, and may be under-reported to national surveillance systems, the present study was conducted to assess the incidence, features, and outcomes of microbiologically confirmed cases of pneumococcal meningitis in North Yorkshire, England, between 1997 and 2002. The review revealed 50 cases, which accounted for an incidence of 1.1. per 100,000 per year. The incidence was markedly seasonal, with 76% of cases occurring in the winter months. Mortality was 28%, and 28% of the survivors suffered long-term sequelae. A high Glasgow Coma Score on hospital admission was significantly associated with survival. There were 12 children in the study, aged 2 months to 2 years, and none of them would have been classified as candidates for conjugate pneumococcal vaccination according to UK recommendations.

Problems associated with indwelling central venous catheters.

Forty nine Broviac or Hickman indwelling central venous catheters were inserted in 36 patients with haematological and neoplastic diseases for indications including young age, intensity of treatment, and psychological attitude. Sixteen patients suffered 29 episodes of infection related to the catheter bacteraemia (0.68 episodes per 100 days of catheter use). Infections occurred much more commonly where there was intensive use of the catheter than with relatively light catheter use. Twenty episodes were caused by a single bacterial strain and nine by multiple strains; coagulase negative staphylococci accounted for 51% of the strains isolated. Altogether 72% of infections were cured by antibiotic treatment, which was more likely to be successful in eradicating single than multiple infections. Although infection was common, mechanical problems were a more usual reason for catheter removal. There were no deaths caused by catheter related infection.

Bacteraemia related to indwelling central venous catheters: prevention, diagnosis and treatment.

Infective episodes in immunocompromised children with indwelling central venous catheters were studied prospectively for one year. Culture of catheter hubs and skin at catheter entry sites during the first six months suggested that hub contamination was important in the pathogenesis of catheter colonization. The incidence of catheter-related bacteraemia, and possible catheter-related bacteraemia, fell by 56.5% following alterations in the protocol for manipulative care of catheters, from 5.82 per 1000 catheter days in the first six months to 2.53 per 1000 catheter days in the subsequent six months. A firm diagnosis of catheter-related bacteraemia was made simply and economically by a pour-plate quantitative blood culture technique. Attempts at eradication of catheter-related bacteraemia without removal of the catheter were successful in all cases.

Prediction of septicemia following endourological manipulation for stones in the upper urinary tract.

We investigated 117 patients undergoing percutaneous nephrolithotomy, percutaneous nephrostomy, ureterorenoscopy, the push-back or push-bang procedure for ureteral stones, Double-J* ureteral stenting plus extracorporeal shock wave lithotripsy (ESWL), ESWL alone or cystoscopy. Blood samples obtained before, during and 1 hour after the procedure were cultured and assayed for endotoxin and tumor necrosis factor. Also, culture was done of the urine preoperatively and postoperatively, and the stones when they could be retrieved. There was a temporal relationship among bacteremia, endotoxemia and elevation of tumor necrosis factor. An unexpected finding was peroperative endotoxemia in a significant number of patients with stones. Risk factors noted for postoperative bacteremia, endotoxemia and/or elevation of tumor necrosis factor included preoperative endotoxin level, type of procedure, presence of preoperative bacteriuria and pyuria. With respect to the procedure the risk was greatest after the push-back method and least after cystoscopy (push-back method greater than percutaneous nephrolithotomy/percutaneous nephrostomy greater than Double-J stenting plus ESWL greater than ureterorenoscopy greater than ESWL greater than cystoscopy). If the risk factors are measured preoperatively it may be possible to identify the risk of postoperative bacteremia/endotoxemia and, therefore, septic shock postoperatively. Our patients appear to be a good clinical model to investigate the problems related to septicemia.