Nosocomial herpes simplex virus infection associated with oral endotracheal intubation

Healthcare-associated viral and bacterial infections in dentistry

Infection prevention in dentistry is an important topic that has gained more interest in recent years and guidelines for the prevention of cross-transmission are common practice in many countries. However, little is known about the real risks of cross-transmission, specifically in the dental healthcare setting. This paper evaluated the literature to determine the risk of cross-transmission and infection of viruses and bacteria that are of particular relevance in the dental practice environment. Facts from the literature on HSV, VZV, HIV, Hepatitis B, C and D viruses, Mycobacterium spp., Pseudomonas spp., Legionella spp. and multi-resistant bacteria are presented. There is evidence that Hepatitis B virus is a real threat for cross-infection in dentistry. Data for the transmission of, and infection with, other viruses or bacteria in dental practice are scarce. However, a number of cases are probably not acknowledged by patients, healthcare workers and authorities. Furthermore, cross-transmission in dentistry is under-reported in the literature. For the above reasons, the real risks of cross-transmission are likely to be higher. There is therefore a need for prospective longitudinal research in this area, to determine the real risks of cross-infection in dentistry. This will assist the adoption of effective hygiene procedures in dental practice.

Microsatellite analysis of HSV-1 isolates: from oropharynx reactivation toward lung infection in patients undergoing mechanical ventilation

BACKGROUND

According to recent reports, herpes simplex virus type 1 (HSV-1) induces bronchopneumonitis (BPn) in immunocompetent patients undergoing prolonged mechanical ventilation (MV), whose respiratory functions deteriorate with a poor outcome. HSV-1 BPn is associated with HSV symptomatic or symptomless reactivation in the oropharynx.

OBJECTIVES

We sought to systematically and genetically characterize HSV-1 strains isolated from immunocompetent patients receiving prolonged MV and to characterize the genetic relationship of strains sequentially isolated from oropharyngeal samples (OPS) and broncho-alveolar liquids (BAL) to determine the natural course of HSV BPn.

STUDY DESIGN

In this molecular epidemiological study, microsatellite technology was used to determine genetic relationships between 211 HSV-1 strains isolated from OPS and/or BAL from 106 patients receiving MV.

RESULTS

Microsatellite haplotypes of HSV-1 strains sequentially isolated from the same individual were identical, and HSV-1 isolates from the lung were genetically indistinguishable from strains isolated from the oral cavity. Each patient was characterized by their own HSV-1 microsatellite haplotype, and no nosocomial transmission of strains between patients was observed.

CONCLUSION

Our results demonstrate that, in patients who receive MV, the HSV-1 pulmonary infection results from the reactivation of genetically related HSV-1 in the oropharynx, which progressively infects the lower respiratory tract.

Clinical relevance of and risk factors for HSV-related tracheobronchitis or pneumonia: results of an outbreak investigation

Introduction

Herpes simplex virus (HSV) type 1 was identified in respiratory specimens from a cluster of eight patients on a surgical intensive care unit within 8 weeks. Six of these patients suffered from HSV-related tracheobronchitis and one from HSV-related pneumonia only. Our outbreak investigation aimed to determine the clinical relevance of and risk factors associated with HSV-related tracheobronchitis or pneumonia in critically ill patients, and to investigate whether the cluster was caused by nosocomial transmission.

Methods

A retrospective cohort study was performed to identify risk factors for the outcomes of HSV-related tracheobronchitis or pneumonia and death using univariable analysis as well as logistic regression analysis. Viruses were typed by molecular analysis of a fragment of the HSV type 1 glycoprotein G.

Results

The cohort of patients covering the outbreak period comprised 53 patients, including six patients with HSV-related tracheobronchitis and one patient with pneumonia only. HSV-related tracheobronchitis or pneumonia was associated with increased mortality (100% in patients with versus 17.8% in patients without HSV-related tracheobronchitis or pneumonia; P < 0.0001). The interaction of longer duration of ventilation and tracheotomy was associated with HSV-related tracheobronchitis or pneumonia in multivariable analysis.

Identical HSV type 1 glycoprotein G sequences were found in three patients and in two patients. The group of three identical viral sequences belonged to a widely circulating strain. The two identical viral sequences were recovered from bronchoalveolar lavages of one patient with HSV-related tracheobronchitis and of one patient without clinical symptoms. These viral sequences showed unique polymorphisms, indicating probable nosocomial transmission.

Conclusion

HSV-related tracheobronchitis or pneumonia is associated with increased mortality in critically ill patients. Care should be taken to avoid nosocomial transmission and early diagnosis should be attempted.

Treatment of mucocutaneous presentations of herpes simplex virus infections

Infections by herpes simplex virus (HSV) types I and II are diverse and quite frequent. After primary infection, the virus establishes a life-long latency in the sensory ganglia and recrudescences may occur at an unpredictable rate. Recurrent labial and genital herpes infections represent the majority of clinical manifestations of HSV infections. Their management is currently well established using evidence-based medicine data. Primary labial herpes is generally not treated with antivirals in otherwise healthy children, although intravenous aciclovir may be offered in severe primary infections, particularly in the immunocompromised patient. The decision whether or not to treat recurrent labial herpes should be evaluated individually and depends on the frequency and severity of relapses, the impairment of the quality of life, and the cost of therapy. Patients with mild disease may benefit from topical therapy, and those with severe and frequent recurrences may be considered for intermittent or long-term oral antiviral therapy. Primary genital herpes is treated with oral or intravenous antivirals, depending on the severity of the infection and associated symptoms. Recurrent genital herpes can be managed with episodic short courses of oral antivirals in patients whose recurrences are moderate to severe and rare, and have a clear prodrome. Patients with >5 episodes/year, severe recurrences or unrecognisable prodromes may be best managed with long-term suppressive antiviral prophylaxis. HSV is also responsible for a variety of other clinical manifestations, including herpetic whitlow, neonatal infection, disseminated and atypical cutaneous infections, traumatic herpes, eczema herpeticum, and HSV-associated erythema multiforme. HSV infection may also represent a complication following cosmetic procedures of the oro-facial region, surgical and dental interventions, sun exposure and burns. Precise treatment guidelines for these HSV infections are not firmly established.

[Debates and updates regarding the virologic diagnosis of herpes]

Clinical diagnosis of herpes simplex virus infections is accurate and sufficient in many cases. However, there are situations where diagnosis is difficult, for example in subclinical shedding or atypical lesions. Furthermore, in some life-threatening conditions such as encephalitis, herpesvirus infections in immunocompromised individuals, during pregnancy or in neonates, confirmation of the diagnosis with accurate and rapid laboratory tests is essential.

Herpes Simplex Infections in the Critical Care Setting

Infections caused by herpes simplex virus (HSV) types 1 and 2 are widely prevalent and usually asymptomatic. In the immunocompromised or severely ill patient, however, HSV can cause a variety of mucosal and systemic syndromes. Organ systems most susceptible include the gastrointestinal tract, lungs, and the central nervous system. Systemic disseminated disease may also occur. With the exception of herpes encephalitis, clinical diagnosis of serious HSV infections is difficult, because it occurs in hosts who are susceptible to a wide range of infectious and metabolic problems. We review the presenting syndromes of HSV infection in the critically ill patient, and outline current concepts for diagnosis and treatment.