Real-time TaqMan PCR for rapid detection of genes encoding five types of non-metallo- (class A and D) carbapenemases in Enterobacteriaceae.

A real-time TaqMan multiplex polymerase chain reaction (PCR) assay was developed to detect genes encoding five types of serine carbapenemases (GES, IMI/NMC, KPC, OXA-48 and SME). The assay was validated using control strains known to produce each of these types of enzyme and was then further assessed by 'blindly' testing 59 previously characterised clinical isolates, including 19 with serine (KPC or OXA-48) carbapenemases, 22 with metallo- (IMP, VIM or NDM) carbapenemases, and 18 with carbapenem resistance contingent upon extended-spectrum ß-lactamase (ESBL) or AmpC production combined with porin loss. The assay detected and correctly assigned the serine carbapenemases in all five positive control strains and in 19 clinical isolates. No false-positive results were seen for isolates with metallo-enzymes or for those that lacked a carbapenemase. The five serine carbapenemase genotypes could also be distinguished by melt-curve analysis or the molecular size of the amplicons.

Doxycycline or moxifloxacin for the management of community-acquired pneumonia in the UK?

Macrolide monotherapy is currently recommended as first-line treatment of mild-to-moderate community-acquired pneumonia (CAP) in penicillin-intolerant/allergic individuals in the UK. However, resistance rates among the commonest cause, Streptococcus pneumoniae, now exceed 10% in the UK and a review of alternative agents is therefore timely. This review considers the relative merits of two agents, doxycycline and moxifloxacin, which are candidates to replace macrolides for second-line therapy of non-severe CAP.

Non-fermentative Gram-negative bacteria.

Over the past decade, non-fermenting Gram-negative bacteria have emerged as important opportunistic pathogens in the increasing population of patients who are immunocompromised by their disease or medical treatment. These bacteria are assisted by their ubiquitous distribution in the environment and have a propensity for multiple, intrinsic or acquired drug resistance. The infections that they cause now pose significant problems in terms of treatment and infection control, whilst the commonly observed rapid emergence of bacterial resistance to new antimicrobial compounds raises concerns regarding the clinical lifespan of these agents. Studies are urgently required to assess whether combination therapy can improve the long-term utility of new drugs in the treatment of patients infected with non-fermenters.

Invasive fungal infections: a review of epidemiology and management options.

Fungi are increasingly recognised as major pathogens in critically ill patients. Candida spp. and Cryptococcus spp. are the yeasts most frequently isolated in clinical practice. The most frequent filamentous fungi (moulds) isolated are Aspergillus spp., but Fusarium spp., Scedosporium spp., Penicillium spp., and Zygomycetes are increasingly seen. Several reasons have been proposed for the increase in invasive fungal infections, including the use of antineoplastic and immunosuppressive agents, broad-spectrum antibiotics, and prosthetic devices and grafts, and more aggressive surgery. Patients with burns, neutropenia, HIV infection and pancreatitis are also predisposed to fungal infection. The epidemiology and clinical features of fungal infections are reviewed, together with antifungal agents currently or soon to be available.

A pseudo-outbreak of respiratory infection with Acinetobacter species.

We describe an apparent outbreak of respiratory infection with Acinetobacter species involving 14 patients over 8 days. Epidemiological investigation revealed two consecutive pseudo-outbreaks of infection caused by two consecutive, unrelated laboratory errors in the processing of sputum, nasopharyngeal, and endotracheal aspirates.

Detection by PCR and analysis of the distribution of a fibronectin-binding protein gene (fbn) among staphylococcal isolates.

The fibronectin-binding proteins of Staphylococcus aureus are considered to be important virulence factors for colonisation and infection. The polymerase chain reaction (PCR) was used to detect part of a gene equivalent to the fbnA gene of S. aureus in 120 isolates of staphylococci (S. aureus, S. epidermidis, S. haemolyticus, S. simulans, S. hominis, S. warneri, S. cohnii and S. lugdunensis). Primers specific for the binding domain region of the fbnA gene of S. aureus produced PCR products of the predicted sizes (93 and 207 bp). The identity of the PCR products was confirmed by digestion with DdeI and nucleic acid hybridisation. The fibronectin-binding activity of the staphylococci was determined with a particle agglutination assay (PAA). The fbn gene was found to be present by PCR in 107 of the 120 staphylococci tested, irrespective of their site of isolation, and expression of the gene was detected by PAA in 101 of the 120 strains.

Linkage of vancomycin and high-level gentamicin resistance genes on the same plasmid in a clinical isolate of Enterococcus faecalis.

A transferable 55-MDa plasmid which encoded resistance to both vancomycin and high concentrations of gentamicin was identified in a clinical isolate of Enterococcus faecalis. The plasmid hybridized with probes for the vanB and aac6'aph2" resistance genes. This is the first report of linkage of glycopeptide and high-level aminoglycoside resistance genes in an Enterococcus sp.

Infective complications associated with the use of the Quinton 'Permcath' for long-term central vascular access in haemodialysis.

The major complication of central venous catheterization for immediate access for haemodialysis is infection. The Quinton Permcath is a tunnelled, double lumen, flexible silastic catheter with a Dacron cuff, and is claimed to be associated with a low rate of infection. In a two-year study we have monitored all complications including catheter-associated infection related to this device in haemodialysis patients while following a simple aseptic programme for the care of the catheter exit wound. Thirty four Permcaths were inserted in 30 patients for a mean duration of 6.2 months (SD +/- 5.7; range 2 days to 23 months). Catheter use amounted to a total of 197 months. Of twenty-seven catheter wound infections, 6 (22%) were caused by Staphylococcus aureus, and 15 (56%) by coagulase-negative staphylococci or corynebacteria. These occurred in 19 patients, giving an exit site infection rate of one episode per 7.4 catheter months. Catheter-associated septicaemia occurred in three patients (two S. aureus, one S. epidermidis), at a rate of one episode per 66 months. It was possible to correlate three episodes of infection with breakdown in aseptic care. This study confirms the low rate of infection associated with the use of the Permcath, and we conclude that the design of the device and aseptic care of the catheter and its wound contribute to this.

Infectious consequences of continuous ambulatory peritoneal dialysis.

The peritoneal cavity of patients undergoing CAPD is critically immunocompromised and infectious peritonitis is the most important complication of the technique. Nevertheless, recent research into the epidemiology and pathogenesis of infections caused by the most important microorganisms has enabled significant reductions in peritonitis rates to be made. Peritonitis caused by Staphylococcus aureus and Pseudomonas aeruginosa can be prevented by eliminating their principal source, an infected Tenckhoff catheter wound. The source of infection for coagulase-negative staphylococci and other pseudomonads cannot be eliminated, but peritonitis caused by these organisms may be prevented by interrupting their routes of entry into the peritoneal cavity. The identification of host factors predictive of enhanced susceptibility to infectious peritonitis offers the further possibility of prevention by immunological approaches. Although the main difficulties surrounding the diagnosis of infective peritonitis have been clarified, approximately 20% of episodes remain culture-negative, with multifactorial aetiology. Initial (empirical) combination antibiotic therapy can be both appropriate and effective in approximately 85% of cases. Intraperitoneal monotherapy with fluoroquinolones has been equally successful, and these agents may prove effective by the oral route, offering considerable advantages in cost and convenience. Approximately 5% of episodes of bacterial peritonitis are unresponsive to antibiotic therapy. These cases may be conveniently managed by the technique of Tenckhoff catheter removal and replacement at a single operation.

Active intervention dramatically reduces CAPD-associated infection.

In 1987 a preventive programme was initiated to address the problem of high hospital and community-acquired CAPD infection. It concentrated on reducing Staphylococcus aureus carriage, improving aseptic operative technique, intensive training for nursing staff and patients in stringent aseptic care of the exit site, and avoidance of contact of the exit site with unsterile water. This programme was associated with an overall 10-fold reduction in exit site infection, a 2-fold reduction in peritonitis, and a 4.5-fold reduction in catheter loss from infection. These reductions have been sustained. Preventing infection in CAPD patients requires persistence and commitment but improves the patient's quality of life and reduces the cost of treatment.

Intraperitoneal ciprofloxacin for the treatment of peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD).

Ciprofloxacin was evaluated as single-agent therapy for the empirical treatment of patients presenting with CAPD peritonitis in an open, uncontrolled trial. Seventy-five episodes of peritonitis in 44 patients receiving continuous ambulatory peritoneal dialysis were entered in the study. The antibiotic was administered intraperitoneally, at a dose of 50 mg/l in each bag of dialysate, for seven days. Treatment with ciprofloxacin was appropriate (organisms isolated sensitive to ciprofloxacin) and successful (clinical and bacteriological cure of peritonitis) in 62 (83%) of the 75 episodes. The mean ciprofloxacin concentrations in serum and effluent were 1.1 mg/l (range 0-2.9 mg/l) and 10.0 mg/l (range 0.2-33.4 mg/l), respectively, with no evidence of accumulation. Side effects were seen in two patients only, and were mild and transitory.

The prevention of infection with Staphylococcus aureus in continuous ambulatory peritoneal dialysis.

We describe the control of wound infection with Staphylococcus aureus in patients undergoing continuous ambulatory peritoneal dialysis at St. Thomas' Hospital. Forty-nine percent of 61 catheters inserted in 1985 and 1986 became infected, and the majority of these infections were acquired in hospital. Infection was impossible to eradicate and was frequently associated with the subsequent development of S. aureus peritonitis, which was the most important cause of catheter loss. Strict adherence to aseptic techniques for catheter insertion and care, combined with eradication of S. aureus carriage, reduced the infection rate to 12% for the 50 catheters inserted in 1987, abolished hospital-acquired infection and reduced the S. aureus peritonitis rate tenfold, without the use of prophylactic antibiotics. S. aureus infection is a serious but avoidable complication of continuous ambulatory peritoneal dialysis.