[Safety in the Microbiology laboratory]. / Seguridad en el laboratorio de Microbiología Clínica.

The normal activity in the laboratory of microbiology poses different risks - mainly biological - that can affect the health of their workers, visitors and the community. Routine health examinations (surveillance and prevention), individual awareness of self-protection, hazard identification and risk assessment of laboratory procedures, the adoption of appropriate containment measures, and the use of conscientious microbiological techniques allow laboratory to be a safe place, as records of laboratory-acquired infections and accidents show. Training and information are the cornerstones for designing a comprehensive safety plan for the laboratory. In this article, the basic concepts and the theoretical background on laboratory safety are reviewed, including the main legal regulations. Moreover, practical guidelines are presented for each laboratory to design its own safety plan according its own particular characteristics.

Investigation of the first laboratory-acquired human cowpox virus infection in the United States.

BACKGROUND: Cowpox virus is an Orthopoxvirus that can cause infections in humans and a variety of animals. Infections occur in Eurasia; infections in humans and animals have not been reported in the United States. This report describes the occurrence of the first known human case of laboratory-acquired cowpox virus infection in the United States and the ensuing investigation. METHODS: The patient and laboratory personnel were interviewed, and laboratory activities were reviewed. Real-time polymerase chain reaction (PCR) and serologic assays were used to test the patient's specimens. PCR assays were used to test specimens obtained during the investigation. RESULTS: A specimen from the patient's lesion tested positive for cowpox virus DNA. Genome sequencing revealed a recombinant region consistent with a strain of cowpox virus stored in the research laboratory's freezer. Cowpox virus contamination was detected in 6 additional laboratory stocks of viruses. Orthopoxvirus DNA was present in 3 of 20 environmental swabs taken from laboratory surfaces. CONCLUSIONS: The handling of contaminated reagents or contact with contaminated surfaces was likely the mode of transmission. Delays in recognition and diagnosis of this infection in a laboratory researcher underscore the importance of a thorough patient history-including occupational information-and laboratory testing in facilitating a prompt investigation and application of control and remediation measures.

A SHORT HISTORY OF OCCUPATIONAL DISEASE: 1. LABORATORY-ACQUIRED INFECTIONS.

Laboratory-acquired infections are as old as laboratories themselves. As soon as the culture of microorganisms was introduced, so too was their transfer to laboratory workers. It is only in relatively recent history that such infections have been fully understood, and methods of spread and their prevention or avoidance developed. This paper endeavours to provide an overview of the history of laboratory-acquired infection and the steps taken, particularly in the UK, for its prevention.

Lymphocytic choriomeningitis in a hamster colony causes infection of hospital personnel.

A series of febrile illnesses, some severe, among hospital personnel was traced to an outbreak of lymphocytic choriomeningitis in a hospital research colony of Syrian hamsters. By rapid virus isolation and identification techniques, a definitive diagnosis was made 5 days after specimens were received. This outbreak emphasizes the dangers of working with experimental hamsters and tumor cell lines passaged in them.

Laboratory-acquired vaccinia exposures and infections--United States, 2005-2007.

The last case of naturally acquired smallpox disease, caused by the orthopoxvirus variola virus (VARV), occurred in 1977, and the last laboratory-acquired case occurred in 1978. Smallpox was eradicated largely as the result of a worldwide vaccination campaign that used the related orthopoxvirus, vaccinia virus (VACV), as a live virus vaccine. Routine childhood vaccination for smallpox in the United States was terminated by 1972, but vaccination continues or has been reintroduced for specific groups, including laboratory workers who may be exposed to orthopoxviruses, members of the military, selected health-care workers, and first responders. Severe complications of VACV infection can occur, particularly in persons with underlying risk factors, and secondary transmission of VACV also can occur. VACV is used in numerous institutions for various research purposes, including fundamental studies of orthopoxviruses and use as a vector for the expression of foreign proteins (often antigens or immunomodulators) in eukaryotic cells and animal models. The widespread use of VACV for research has resulted in laboratory-acquired VACV infections, some requiring hospitalization. The current Advisory Committee on Immunization Practices (ACIP) guidelines recommend VACV vaccination for laboratory workers who handle cultures or animals contaminated or infected with nonhighly attenuated VACV strains or other orthopoxviruses that infect humans. This report describes five recent occurrences of laboratory-acquired VACV infections and exposure and underscores the need for proper vaccination, laboratory safety, infection-control practices, and rapid medical evaluation of exposures in the context of orthopoxvirus research.

Adherence to universal precautions among laboratory personnel in Lebanon.

To evaluate the present situation and plan future directions with regard to implementation of universal precautions in laboratories testing blood samples, we carried out a national cross sectional study in 2003 on a representative sample of laboratories in Lebanon. We compared the results with those of a 1993 study. We found that the education profile of staff had improved, being now more specialized in laboratory science. The discrepancies between what technicians knew, believed in and practised and what was observed in the field improved to some extent in most variables. Disposal of needles and syringes had improved greatly but disposal of blood-contaminated material had not. Given the risks of improper practice, a policy of universal precautions is essential and regular training should be carried out so that staff know and practise the universal precautions and correct laboratory procedures.

Cerebrospinal fluid protein and glucose examinations and tuberculosis:Will laboratory safety regulations force a change of practice?

Cerebrospinal fluid (CSF) protein and glucose examinations are usually performed in chemical pathology departments on autoanalysers. Tuberculosis (TB) is a group 3 biological agent under Directive 2000/54/EC of the European Parliament but in the biochemistry laboratory, no extra precautions are taken in its analysis in possible TB cases. The issue of laboratory practice and safety in the biochemical analyses of CSF specimens, when tuberculosis infection is in question is addressed in the context of ambiguity in the implementation of current national and international health and safety regulations. Additional protective measures for laboratory staff during the analysis of CSF TB samples should force a change in current laboratory practice and become a regulatory issue under ISO 15189. Annual Mantoux skin test or an interferon-γ release assay for TB should be mandatory for relevant staff. This manuscript addresses the issue of biochemistry laboratory practice and safety in the biochemical analyses of CSF specimens when tuberculosis infection is in question in the context of the ambiguity of statutory health and safety regulations.

Serological evidence of hantavirus infection in laboratory rats and personnel.

Laboratory-acquired haemorrhagic fever with renal syndrome (HFRS) has been reported in many countries. A serological survey of laboratory white rats and of laboratory personnel for antibodies to hantaviruses was conducted in Singapore. Forty-four per cent (143/329) of rats were seropositive by the indirect immunofluorescent antibody test but none had hantaviral antigens in lung tissues. Two of 74 laboratory personnel were seropositive but neither had a history of clinical illness. The high seropositivity rate among laboratory rats led to their replacement with Hantaan virus-free strains. To eliminate the hazard of laboratory-acquired HFRS, regular serological screening of laboratory rats and replacement of infected animals with seronegative stocks should be implemented. High risk techniques with laboratory rats, which are likely to generate aerosols, should be performed in biological safety cabinets. Serological surveillance of laboratory personnel and reporting of suspected HFRS cases are useful in the early detection of hantavirus infection.

Venereal transmission of hepatitis B virus. The possible role of vaginal secretions.

The presence of Type B viral (Australia antigen related serum) hepatitis in vaginal specimens was investigated and compared with that in saliva specimens in a group of patients during the acute phase of their illness. Hepatitis B surface antigen was detectable in most vaginal and salivary secretions during the phase of antigenemia and not in hepatitis B surface antigen-negative controls. Despite care in collection, occult blood was detected in the majority of specimens, but the positivity for hepatitis B surface antigen did not depend on the presence of occult blood. Recovery studies were performed in both vaginal fluids and saliva to determine if inhibitors to hepatitis B surface antigen were similar to those observed in stool samples. Significant inhibition was not observed. Although infectivity of the specimens was not established from this study, handling of these specimens as potentially infective material is recommended.

Biochemical mis-identification of Brucella melitensis and subsequent laboratory-acquired infections.

Brucella species are mis-identified in the API 20NE system as Moraxella phenylpyruvica (profile number 1200004). Since some Brucella spp. grow readily in routine blood culture medium and may be isolated from patients without clinically obvious brucellosis, the risk of laboratory-acquired brucellosis exists. We describe two such cases.

An assessment of some hazards associated with the collection of venous blood.

Some potential hazards of three commercially available blood collecting devices are compared with the conventional syringe method. A simulated venous system using blood containing a bacterial spore tracer was used to estimate surface and aerosol contamination. No appreciable difference in potential hazard to the operator was demonstrable by the methods employed.

Hazards to laboratory staff posed by fungal pathogens.

There is sufficient evidence from the literature to demonstrate the risk involved in handling the dimorphic pathogens without suitable containment facilities. The number of fungi considered a severe hazard is fortunately low, but impeccable working practices and continuous vigilance are necessary to minimize accidents and to prevent them leading to worse catastrophies. The continuing discovery of new opportunistic pathogenic fungi requires frequent, objective and cautious review of the hazard groupings to accommodate them.

Nosocomial and laboratory-acquired infection with Escherichia coli O157.

Infections caused by verocytotoxigenic Escherichia coli O157 (VTEC O157) have emerged as a major public health concern. The nature and severity of associated clinical sequelae are such that symptomatic cases often require hospitalization, with possible exposure to other patients and healthcare workers, including laboratory personnel, to the risk of acquiring VTEC O157. The occurrence of such episodes of hospital- and laboratory-acquired infections has demonstrated that these concerns are justified. Hospital infection control teams must ensure that staff are aware of this potential hazard, and laboratories must review their operating procedures to ensure that their personnel are not unnecessarily exposed, particularly in the light of revised guidance on the safe handling of these organisms.

Inactivation of the unconventional agents of scrapie, bovine spongiform encephalopathy and Creutzfeldt-Jakob disease.

Scrapie, bovine spongiform encephalopathy (BSE) and Creutzfeldt-Jakob disease (CJD) are the best known of the transmissible degenerative encephalopathies (TDE) that affect animals and man. Among the unusual properties of the unconventional causal agents is their relative resistance to standard decontamination procedures, and this has resulted in accidental transmission. Scrapie in sheep is the most common of these diseases and, through laboratory studies, is the best understood. As the model for the group, scrapie agent has been used in experiments to devise general standards for decontamination of the agents of the TDE.

The risk of hepatitis B infection among health professionals in the United States: a review.

Many physicians, dentists, and allied health personnel sustain occupational exposures to blood and other body fluids that increase their risk of contracting type B viral hepatitis. Overall, the risk of hepatitis B among persons employed in health-related fields is estimated to be approximately four times that in the general adult population. Studies on the incidence of infection and the prevalence of hepatitis B serologic markers have further defined risk in specific occupational categories and work activities. Physicians and dentists are five to ten times more likely than the general adult population to experience hepatitis B infection. Infection rates ten or more times above the average have often been characteristic of surgeons, patient care personnel in dialysis units and institutions for the mentally handicapped, and clinical laboratory workers having frequent contact with blood samples.

Past and present hazards of working with infectious agents.

Over 4,000 cases of laboratory-associated infection have been recorded. Some of the agents involved often in the past have been less frequently the cause of such infection in recent years, and some agents are more likely to infect those working with them than others. Pipetting, the use of a needle and syringe, and spills have been most frequently involved in accidents resulting in infection, but in the majority of cases no recognized accident occurred. In these instances, infectious aerosols, produced in various ways, are probably the most frequent causes of laboratory-associated infection. The introduction of protective devices and emphasis on safe procedures seem to be reducing the risk of accidental infection. Although work with tumor viruses and recombinant DNA research may not be as hazardous as was originally feared, continued caution and surveillance is advised.

Survey of Pseudomonas aeruginosa contamination in human beings and laboratory animals.

Several serotypes of Pseudomonas (P.) aeruginosa were isolated from the oral cavities of researchers, but no positive cases were found among the animals they had contacted or in the environment. These results indicated that researchers are not a source of P. aeruginosa infection for animals. However, P. aeruginosa was detected on the hands of researchers and animal caretakers after they finished their work. The same serotype of P. aeruginosa was found in the animals and the environment. These findings demonstrated that the researchers and the animal caretakers were contaminated with P. aeruginosa by the animals, and then became infective vehicles.

[Epidemiology of human diseases caused by unconventional transmissible agents]. / Epidémiologie des maladies humaines à agents transmissibles non conventionnels.

Human unconventional viruses infections are scarcely found with a worldwide occurrence below 1/million inhabitants. The disease would be induced by an interaction between the patient's genetic characteristics and environmental factors. No link has been found between the occurrence of the disease in man and the presence of the animal form of the disease, i.e. scrapie. The professional risk has been pointed out for people working with animals or in the medical sector. Most iatrogenic cases are subsequent to a growth hormone treatment. The other cases are associated with different medical and surgical acts. But the transmission by blood transfusion remains questionable and must be clearly demonstrated.