PCR offers no advantage over culture for microbiologic diagnosis in cellulitis

PURPOSE

Most cases of cellulitis are traditionally attributed to β-hemolytic Streptococcus and Staphylococcus species, although in most cases, no organism is identified. Development of PCR using the conserved bacterial 16 S rRNA DNA permits identification of bacteria independent of conventional culture approaches and prior use of antibiotics.

METHODS

We used PCR-based techniques to identify cellulitis etiology using aspirate samples from affected skin. Saline was infiltrated and aspirated at the site of greatest erythema or at the cellulitic border. Samples were tested for 16 S rRNA DNA, and organism-specific probes used to identify bacteria commonly seen in skin infections.

RESULTS

Aspirates from 32 patients were studied, and 16 S rRNA DNA was detected in nine of these patient samples (28.1%). Bacterial species were identified by PCR methods in six of these nine samples (66.6%), with S. aureus and methicillin-resistant S. aureus (MRSA) identified in four and two, respectively, of these samples. Of the patients with positive aspirate bacterial cultures (3/9, 33.3%), S. aureus and coagulase-negative Staphylococcus (CoNS) were present on cultures of two of the three (both 66.6%) positive samples. Only in one of the three positive bacterial cultures did the PCR method detect the same organism as was detected by culture. Among patients with positive provider-collected clinical cultures, MRSA was the predominant organism (11/18, 61.1%) and when present, it was found as the sole organism. Where S. aureus or Streptococcus species were detected by molecular methods, clinical cultures yielded a positive result as well.

CONCLUSIONS

PCR-based techniques do not appear to be more sensitive than aspirate cultures for the detection of pathogens in cellulitis.

Infections of the deep neck spaces

Deep neck infections (DNI) have a propensity to spread rapidly along the interconnected deep neck spaces and compromise the airway, cervical vessels and spinal canal. The value of imaging lies in delineating the anatomical extent of the disease process, identifying the source of infection and detecting complications. Its role in the identification and drainage of abscesses is well known. This paper pictorially illustrates infections of important deep neck spaces. The merits and drawbacks of imaging modalities used for assessment of DNI, the relevant anatomy and the possible sources of infection of each deep neck space are discussed. Certain imaging features that alter the management of DNI have been highlighted.

[Skin and soft tissue infections]

Skin- and Soft tissue infections are a frequent problem in hospital as well as in ambulatory care. Diagnostic procedures and treatment principles have to include the most frequent pathogens. While the acute forms of skin and soft tissue infections, with, necrotising fasciitis as important exception, rarely cause diagnostic or therapeutic problem, the treatment of patients with recurrent furunculosis, chronic wounds and diabetic feet is often difficult and frustration for patients and physicians. This article gives an overview of the most important problems and treatment strategies.

Derm emergencies: detecting early signs of trouble

Life-threatening dermatologic conditions do not always present with classic findings. This review--and the accompanying images--will help you recognize and respond to them without delay.

Severe soft tissue infection of the lower extremity caused by Haemophilus influenzae (serotype f, biotype II) in an adult patient

The infection caused by non-b-type Haemophilus influenzae has been increasing in this Hib (H.influenzae serotype b) vaccination era. H.influenzae serotype f (Hif) is considered as one of those emerging pathogens. In general, H.influenzae is a common pathogen of such as pneumonia, otitis media, and meningitis, but is rare in soft tissue infection, especially at the extremity. We report a rare case of severe soft tissue infection caused by Hif which occurred at the lower extremity of immunocompetent adult patient.

Bedside ultrasound performed by novices for the detection of abscess in ED patients with soft tissue infections

OBJECTIVE

The objective was to compare bedside ultrasound (US) to clinical examination for the detection of abscess.

METHODS

This is a 24-month prospective, observational emergency department (ED) study. Adults with suspected nondraining abscess with planned incision and drainage (I&D) are included in the study. Exclusion criteria are spontaneous drainage and perineal, perirectal, or intraoral location. Before I&D, a second ED physician conducts an US and records the presence or absence of findings suggestive of abscess. A positive I&D of the suspected abscess is the criterion standard. The treating practitioner is blinded to the US results. Ultrasound is performed by novice ED physicians. The findings of the US, the prediction of pus from the clinician and the ultrasonographer in 3 strata (low, indeterminate, definite), and the results of the I&D (pus/no pus) are recorded onto data sheets. Measures of association are reported and Fisher's Exact test is used.

RESULTS

Forty patients were enrolled. The sensitivity of novice sonographers to predict a positive I&D with US was 0.97 (0.83-1.00), the specificity was 0.67 (0.24-0.94), the positive likelihood ratio was 2.90, the negative likelihood ratio was 0.04, and the area under the receiver operating characteristic curve was 0.85 (0.66-1.00). Clinical examination yielded a sensitivity of 0.76 (0.58-0.89), specificity of 0.83 (0.36-0.99), positive likelihood ratio of 4.50, negative likelihood ratio of 0.29, and area under the receiver operating characteristic curve of 0.75 (0.50-1.00).

CONCLUSION

Novice ED sonographers can identify abscesses with only minimal US training. Identification of abscess on US may change management of cutaneous abscesses.

[The actual approaches to laboratory diagnostics of anaerobic non-clostridial infection (a lecture)]

The actual approaches to laboratory diagnostics of anaerobic non-clostridial infection using gas chromatography and mass spectrometry are described. The data concerning anaerobes' indication in analyt is presented. The focus is made on molecular markers, chemotaxonomy and classitic mechanisms of interaction between germ and organism on molecular level. The express determination of anaerobes' sensitivity to chemotherapeutical preparations is discussed.

Necrotizing fasciitis following BCG vaccination

We report a newborn with methicillin-resistant Staphylococcus aureus mediated necrotizing fasciitis after Bacilli-Calmette-Guerin vaccination. Radical debridement of the affected area coupled with twice daily surgical honey dressing and intravenous vancomycin and clindamycin resulted in satisfactory healing.

Primary cutaneous cryptococcosis in a renal transplant recipient: case report

We report a kidney transplant recipient with severe skin- and soft-tissue infection mimicking necrotising fasciitis. Patient failed to respond to empirical antibiotic therapy for presumed bacterial cellulitis. Culture of aspirate from the wound and tissue samples revealed Cryptococcus neoformans. No signs of systemic cryptococcal infection were found. After antifungal treatment and surgical intervention, complete healing was achieved. Clinical and microbiological characteristics of this patient are discussed. Our case indicates that primary cutaneous cryptococcosis must be included in the differential diagnosis of severe cellulitis in solid organ transplant recipients not responding to broad-spectrum antibiotic regimens. In our case, prompt diagnosis and treatment could dramatically modify the outcome.

Ecthyma-like phaeohyphomycosis caused by Cladosporium cladosporioides

A case of cutaneous phaeohyphomycosis caused by Cladosporium cladosporioides in a 50-year-old housewife is described. The clinical presentation was an ecthyma-like crusted lesion on the back of her left hand. Scanning electron microscopy of the culture showed the conidiophores and the limoniform or ellipsoidal conidia, with a slightly verrucous surface. The lesion was removed surgically, with no relapses after 6-month follow up.

Wound fluid lactate concentration: a helpful marker for diagnosing soft-tissue infection in diabetic foot ulcers? Preliminary findings

AIMS

To investigate the impact of wound fluid lactate concentration on diagnosing soft-tissue infection in diabetic foot ulcers.

METHODS

Lactate concentration in wound fluid obtained from diabetic foot ulcers was determined using a lactate analyser and compared with clinical examination findings.

RESULTS

Overall median wound fluid lactate concentration was 21.03 mm (5.58-80.40 mm). Wound lactate levels were significantly higher in infected compared with non-infected diabetic foot ulcers (P=0.001). Non-infected diabetic foot ulcers that healed within 6 months of treatment showed a significantly lower wound fluid lactate concentration at baseline as opposed to those that did not heal (P=0.007).

CONCLUSIONS

Non-healing diabetic foot ulcers are characterized by high wound fluid lactate levels. Assessment of wound fluid lactate concentration might be helpful for confirming the suspicion of soft tissue infection, particularly when clinical signs are atypical.

[Pathognomonic presentation of Kingella kingae infection]

Kingella kingae is an important and probably under-recognized pathogen in children. It has a predilection for bones, joints and vascular endothelium, but can also cause bacteraemia alone. We present a case of Kingella kingae that manifested itself by presternal soft tissue infection, and suggest that infection of the lower sternum and the junction between the manubrium and the xyphoid process are typical, if not pathognomonic for the organism.

The problem of complicated skin and skin structure infections: the need for new agents

Complicated skin and skin structure infections (cSSSIs) continue to pose a significant clinical challenge. The most frequent cause of these infections is Staphylococcus aureus, although other organisms, including Streptococcus pyogenes and, in certain circumstances, Enterobacteriaceae, are also involved. The relentless increase in methicillin resistance among S. aureus isolated in hospitals throughout the world has made it important to provide coverage for these organisms when treating cSSSIs in hospitals. More recently, however, there has been a striking increase in methicillin resistance among staphylococci isolated from infections acquired in the community, particularly in the USA. As a result, previous recommendations for empirical therapy of these important infections are now outdated. The papers in this Supplement detail the properties of a new broad-spectrum cephalosporin that has activity against MRSA and is, thus, an outstanding candidate for empirical therapy of cSSSIs. The papers included provide data on the in vitro activity, pharmacokinetics and pharmacodynamics as well as the clinical efficacy of ceftaroline fosamil, which is a welcome addition to our therapeutic armamentarium against cSSSIs.

[Rapid infection of bone and soft tissues of the upper extremity--case report]

Long duration of intravenous drug abuse brings the risk of infectious and surgical complications. The case report of the forearm soft tissue and bone infection followed by rapid progress of compartment syndrome is described. Primary bone infection is unusual. It is necessary to think about it if the treatment of soft tissues comes short of the inflammation suppression. Especially if an intravenous drug abuser is concerned. The case stresses the necessity of thinking of all the diagnostic possibilities and bone affliction with its risks and of the well-timed treatment urgency.

Predisposing factors of complicated deep neck infections: 12-year experience at a single institution

OBJECTIVES

To review our experience with deep neck infections and identify the risk factors for developing complications and prolonged hospitalization.

SUBJECTS AND METHODS

We analyzed the prospectively collected database of 439 patients with deep neck infections between January 1996 and July 2007 at a single institution. Their demographic data, duration of hospitalization, etiology, underlying systemic disease, bacteriologic and radiologic studies, complications, and treatment outcome were reviewed and analyzed. Patients with superficial abscess or cellulitis, necrotizing fasciitis, and peritonsillar abscess were excluded.

RESULTS

Dental infection and upper airway infection remained the two most common etiologies. Coexisting head and neck malignancy was found in eight cases. Patients with systemic diseases and a C-reactive protein value of more than 100 microg/mL tend to develop complications, resulting in prolonged hospitalization.

CONCLUSION

We should pay more attention to those patients with systemic diseases or C-reactive protein values more than 100 microg/mL. The current study represents the largest and longest analysis of deep neck infection in the available literature.

Staphylococcus aureus infections in adolescents

Staphylococcus aureus infections are important causes of morbidity and mortality in the pediatric population. Over the past decade, community-associated methicillin-resistant S. aureus has emerged as an adolescent pathogen with disease ranging from mild skin and soft tissue infections to severe sepsis syndrome. Various conditions and behaviors common to adolescents render them more susceptible to staphylococcal infections. This review focuses on the problem of S. aureus in the adolescent population, including an outline on the approach, treatment, and prevention of these infections.