Assessment of laboratory and biosafety practices associated with bacterial culture in veterinary clinics

J. Scott Weese Department of Pathobiology and Centre for Public Health and Zoonoses, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.

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 DVM, DVSc, DACVIM
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John F. Prescott Department of Pathobiology and Centre for Public Health and Zoonoses, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.

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 VetMB, PhD

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Abstract

Objective—To investigate bacterial culture practices in veterinary clinics, with an emphasis on laboratory biosafety and on quality of laboratory practices.

Design—Survey-based prospective study.

Sample Population—166 veterinarians.

Procedures—Veterinarians were recruited through the Veterinary Information Network (an Internet-based network restricted to veterinary personnel). All Network-registered veterinarians were eligible to participate. A standardized questionnaire regarding bacterial culture practices in veterinary clinics was completed electronically by study participants.

Results—720 veterinarians completed the survey; 166 (23%) indicated that bacterial culture was performed in his or her clinic. Clinic practices ranged from preliminary aerobic bacterial culture only with submission of isolates to a diagnostic laboratory for further testing (93/160 [58%]) to bacterial culture, identification, and antimicrobial susceptibility testing (19/160 [12%]). Most commonly, urine samples were cultured (151/162 [93%] clinics). Several prob-lematic practices were identified regarding quality and quality control, including inadequate facilities, equipment, supervision, interpretation of data, and culture methods. Biosafety infractions were also common, including inadequate laboratory location, lack of biosafety protocols, and dangerous disposal practices. Ninety-four percent of respondents stated that continuing education regarding culture practices and laboratory safety would be useful.

Conclusions and Clinical Relevance—Data confirmed that bacterial culture was commonly performed in clinics, but that major deficiencies in laboratory methods were widespread. These could result in negative effects on testing quality and increased risk of laboratory-acquired infections among clinic personnel. Veterinary practices in which bacterial cultures are performed must ensure that adequate equipment, facilities, personnel, and training are provided to enable accurate and safe sample testing.

Abstract

Objective—To investigate bacterial culture practices in veterinary clinics, with an emphasis on laboratory biosafety and on quality of laboratory practices.

Design—Survey-based prospective study.

Sample Population—166 veterinarians.

Procedures—Veterinarians were recruited through the Veterinary Information Network (an Internet-based network restricted to veterinary personnel). All Network-registered veterinarians were eligible to participate. A standardized questionnaire regarding bacterial culture practices in veterinary clinics was completed electronically by study participants.

Results—720 veterinarians completed the survey; 166 (23%) indicated that bacterial culture was performed in his or her clinic. Clinic practices ranged from preliminary aerobic bacterial culture only with submission of isolates to a diagnostic laboratory for further testing (93/160 [58%]) to bacterial culture, identification, and antimicrobial susceptibility testing (19/160 [12%]). Most commonly, urine samples were cultured (151/162 [93%] clinics). Several prob-lematic practices were identified regarding quality and quality control, including inadequate facilities, equipment, supervision, interpretation of data, and culture methods. Biosafety infractions were also common, including inadequate laboratory location, lack of biosafety protocols, and dangerous disposal practices. Ninety-four percent of respondents stated that continuing education regarding culture practices and laboratory safety would be useful.

Conclusions and Clinical Relevance—Data confirmed that bacterial culture was commonly performed in clinics, but that major deficiencies in laboratory methods were widespread. These could result in negative effects on testing quality and increased risk of laboratory-acquired infections among clinic personnel. Veterinary practices in which bacterial cultures are performed must ensure that adequate equipment, facilities, personnel, and training are provided to enable accurate and safe sample testing.

Bacterial culture is an important part of diagnosis and management of various infectious diseases in veterinary medicine, and specimens for culture are routinely collected in veterinary clinics. Although there are numerous commercial diagnostic laboratories offering a range of microbiological services, some veterinarians may choose to perform bacterial cultures of samples within their practices, for various reasons. However, in exploiting the benefits associated with inhouse culture procedures, there are laboratory quality and biosafety practices that should not be overlooked. For example, laboratory-acquired infections are an important concern in diagnostic and research laboratories; despite the use of standard and rigorous biosafety protocols, there were more than 5,000 infections and 190 deaths attributed to exposure to microorganisms in laboratory settings, although the time period involved was unclear.1 These figures are presumably underestimations because most laboratory-acquired infections are not reported or even identified as being of laboratory origin2 and there are no active monitoring or surveillance programs in place to collect data on laboratory-acquired infections.3

Most commercial diagnostic laboratories work under strict quality control systems with experienced personnel to provide consistent and accurate results. Although not insurmountable, there can be challenges in developing a similar degree of quality control and laboratory biosafety in a veterinary clinic. To the authors' knowledge, there has been minimal prior investigation of bacterial culture practices in veterinary clinics. A study4 of veterinary practices regarding their expectation of competency of new graduates in clinical bacteriology reported that bacterial culture was performed in 42.3% of 410 clinics. However, in that study, many aspects of in-house culture procedures were not scrutinized, and it is likely that practices and perceptions have changed in the 23-year interval since that study. The purpose of the study reported here was to investigate bacterial culture practices in veterinary clinics, with an emphasis on laboratory biosafety and on quality of laboratory practices.

Materials and Methods

The University of Guelph Research Ethics Board approved the study. A survey regarding culture practices in veterinary clinics was developed and tested with a small group of veterinarians. The survey is available from the authors upon request. The survey was then administered through the Veterinary Information Network,5 an Internet-based network that is restricted to veterinary personnel. An invitation to participate in the survey was placed on the Network's home page, which is accessible by the network's 24,000 members. The survey was completed electronically. For data analyses, each respondent was considered to represent a different clinic. Descriptive statistics were applied to the collected data; categoric comparisons were performed by use of a F2 test. A value of P < 0.05 was considered significant for all comparisons.

Results

Demographics—The survey was completed by 720 veterinarians; 684 (95.0%) were from private practice, and 36 (5.0%) were from referral practice. The number of different veterinary clinics involved was not determined because of the anonymous nature of survey responses. Most were from the United States (620 [86%]) or Canada (73 [10%]), with smaller numbers from Australia (9 [1.3%]) and the United Kingdom (5 [0.7%]). There were 2 (0.3%) participants from each of 3 countries (Finland, Israel, and Taiwan) and 1 (0.1%) participant from each of 7 countries (Germany, Spain, Japan, China, Republic of Singapore, Sweden, and Switzerland).

Six hundred forty-one of 713 (90%) participants were engaged in small animal practice, whereas 56 (7.9%) were in mixed-animal practice, 9 (1.3%) were in avian and exotics practice, 6 (0.8%) were in equine practice, and 1 (0.1%) was in food animal practice. The remaining participants did not specify a practice type.

One hundred sixty-six of the 720 (23%) respondents indicated that bacterial culture was performed in their clinic. There was a significant difference in the prevalence of clinics reported as performing bacterial culture, with 5 of 6 (83%) respondents from equine clinics, 20 of 56 (36%) respondents from mixed-animal clinics, 138 of 501 (22%) respondents from small animal clinics, and 1 of 8 (13%) respondents from avian and exotics clinics indicating that bacterial culture was performed in their clinic (P = 0.004). Only data obtained from veterinarians from clinics where in-house bacterial culture was performed were used in the remaining analyses. Because some individuals did not answer all questions, denominators vary slightly.

Specimens cultured at clinics—The scope of bacterial culture was variable (Table 1). In most (152/159 [96%]) clinics, only aerobic bacterial culture was performed. In 6 (3.8%) clinics, aerobic and anaerobic bacterial cultures were performed, and in 1 (0.6%) clinic, aerobic, anaerobic, and microaerophilic bacterial cultures were performed. The reasons stated for performing cultures of samples in the clinic varied. Among the responses from 160 study participants, these reasons included reduced cost to clients (87 [54.4%]), belief that results are more accurate because shipping of specimens is not required (86 [53.8%]), desire of the clinic veterinarians to provide perceived full service (84 [52.5%]), individual employed at the clinic has an interest in microbiology (33 [20.6%]), profitability (29 [18.1%]), results of antimicrobial susceptibility testing are more rapidly available (29 [18.1%]), and lack of access to a good diagnostic laboratory (6 [3.7%]). Various specimens were cultured in different clinics (Table 2). At some clinics, large numbers of different types of specimen were cultured, yet no single clinic cultured the greatest numbers of more than 1 specimen type. In clinics at which a person with advanced microbiological training (beyond standard training provided in programs for veterinarians or veterinary technicians) was employed, blood samples and fine-needle aspirate specimens were more likely to be cultured (P = 0.001 and P = 0.042, respectively), but urine and feces samples, specimens from wounds, nasal swabs, milk samples, reproductive specimens, and respiratory specimens were not more likely to be cultured (all P > 0.05).

Table 1—

Culture practices in veterinary clinics at which bacterial culture was performed as reported by veterinarians (n = 160) who completed an online survey.

Culture practiceNo. of clinics (%)
Preliminary isolation of bacteria with submission of isolates to diagnostic laboratory for identification and antimicrobial susceptibility testing93 (58.1)
Culture and susceptibility testing with some identification30 (18.8)
Culture, identification, and susceptibility testing19 (11.9)
Culture and susceptibility testing but no identification12 (7.5)
Culture and identification but no susceptibility testing6 (3.8)
Table 2—

Types of specimens collected for bacterial culture in veterinary clinics as reported by veterinarians (n = 162) who completed an online survey.

SpecimenNo. of clinics (%)No. of samples cultured/month*
Urine151 (93)1–150
Pus or wound sample70 (43)1–15
Skin swab45 (28)1–45
Fine-needle aspirate35 (22)1–22
Respiratory tract sample33 (20)1–20
Nasal swab22 (14)1–12
Reproductive tract swab22 (14)1–100
Feces11 (6.8)1–100
Milk10 (6.2)1–100

* Data obtained from veterinarians in clinics identified as performing cultures of the specimen type.

Among the 165 clinics for which data were collected, individuals who participated in processing specimens for culture included veterinarians (145 [88%]), technicians (142 [86%]), lay staff (28 [17%]), students (7 [4.2%]), and volunteers (2 [1.2%]).

Laboratory location within clinics—Within 157 survey respondents' clinics, the most common location at which culture procedures were performed was a discrete section of a larger area wherein other procedures were performed (62 [39.5%]), followed by a general treatment room (40 [25.5%]), a separate room wherein microbial cultures and other laboratory techniques were performed (34 [21.7%]), a discrete section of a larger area wherein only microbial cultures were performed (14 [8.9%]), and a separate room wherein only culture was performed (7 [4.5%]). Among the other uses for areas wherein microbial cultures were performed were drug storage (25/134 [18.7%]), consumption of food by humans (6/134 [4.5%]), and storage of food for humans (3/134 [2.2%]).

Bacterial culture facilities—Among the 155 clinics for which data were provided, a laboratory incubator was used most commonly (123 [79.4%]). In 20 (12.9%) clinics, an insulated container with a thermostat-controlled heat source was used, and in 12 (7.7%) clinics, an insulated container with a heat source that was anticipated to provide the desired temperature was used. A built-in conventional thermometer was present in the incubator in 100 of 156 (64.1%) clinics, whereas a thermometer was kept inside the incubator in 38 (24.4%) clinics and a built-in digital thermometer was present in the incubator in 10 (6.4%) clinics. Four (2.6%) clinics periodically placed a thermometer inside the incubator to check the temperature, but another 4 (2.6%) did not monitor temperature whatsoever. A microbiology reference text was available in 103 of 150 (68.7%) clinics.

Antimicrobial susceptibility testing—At 63 of 154 (40.9%) clinics, some form of antimicrobial susceptibility testing of cultured organisms was performed. Disk diffusion was most commonly undertaken at clinics and was reported by 44 of 58 (75.8%) survey respondents; 9 (15.5%) individuals reported that agar dilution was used, and 5 (8.6%) stated that both disk diffusion and agar diffusion were used. Antimicrobial susceptibility testing was performed after bacterial identification in 10 of 61 (16.4%) clinics; in 20 (32.7%) clinics, susceptibility testing was performed after or during bacterial identification, whereas in 17 (27.9%) clinics, susceptibility testing was sometimes done without an attempt to identify the organism. Fourteen of the 61 (23.0%) individuals reported that antimicrobial susceptibility testing was usually done at the clinic without attempting to identify the organism.

At most clinics (45/61 [74%]), a standard panel of antimicrobials was used for susceptibility testing of all isolates, but at the remaining 16 (26.2%) clinics, the tested antimicrobials were tailored to the specific isolate. Fourteen of those 61 (23%) respondents stated that they believed identification was not needed if antimicrobial susceptibility testing was done properly, and 17 (27.9%) stated that basic identification (eg, via Gram staining) was adequate. Twenty-one of 61 (34.4%) respondents stated that definitive identification was required for proper interpretation of antimicrobial susceptibility testing results. Among 60 individuals, only 5 (8.3%) reported that reference strains were used for susceptibility testing quality control in their practices. Clinics that employed a person with advanced training in microbiology were not more likely to have a standard laboratory incubator (P = 0.84), perform antimicrobial susceptibility testing (P = 0.07), have a reference microbiology text (P = 0.26), or use reference (quality control) strains in susceptibility testing (P = 0.68), compared with clinics that did not employ a person with advanced training in microbiology.

Biosafety practices—Survey respondents indicated that there were no guidelines or restrictions regarding protective clothing in 114 of 163 (70%) clinics. In 46 (28%), laboratory coats or scrubs that could be worn elsewhere in the practice were used. Protective outerwear dedicated for use in the laboratory was used in only 2 (1.2%) clinics.

A biohazard sticker or sign was reported to be displayed in the laboratory area in 28 of 158 (17.7%) clinics. Twenty-three (14.6%) respondents stated that there was restricted access to the laboratory, either by policy (18 [11.4%]) or by use of a lockable door (5 [3.2%]). A sink was present in the laboratory area of 140 of 150 (93.3%) clinics. Written laboratory guidelines were available in 55 of 148 (37.2%) clinics, and a biosafety manual was used in 56 of 148 (38%) clinics. Respondents provided information regarding culture plate and contaminated item disposal practices (Table 3).

Table 3—

Methods of disposal of culture plates with visible growth and contaminated disposable culture instruments (ie, inoculating loops) as reported by 150 and 146 veterinarians who completed an online survey, respectively.

ItemMethodNo. of clinics (%)
Culture plateDisposal as biohazardous waste70 (46.7)
Direct disposal in regular garbage41 (27.3)
No disposal; plates with growth are submitted to a diagnostic laboratory16 (10.7)
Sterilization in an autoclave11 (7.3)
Unknown5 (3.3)
Disinfectant applied to plates prior to disposal in regular garbage3 (2.0)
Disinfectant applied to plates prior to disposal as biohazardous waste2 (1.3)
Formalin applied (disposal unspecified)1 (0.7)
Burned in crematorium1 (0.7)
Disposable itemDirect disposal in regular garbage69 (47.3)
Disposal as biohazardous waste57 (39.0)
Disposal in sharps container16 (11.0)
Use of an autoclave4 (2.7)

Compared with clinics where a person with advanced training in microbiology was not employed, required use of dedicated laboratory clothing (P = 0.04), restricted access to the laboratory area (P = 0.016), and application of an appropriate disposal technique (use of an autoclave, disposal as biohazardous waste, or cremation; P = 0.048) were more likely to be in effect in clinics where a person with advanced training in microbiology was employed; however, clinics where such a trained individual was employed were not more likely to have a biohazard sign displayed in the laboratory area (P = 0.08). Veterinarians from clinics that had inappropriate disposal practices were less likely to state that continuing education on biosafety would be useful (P = 0.01), compared with veterinarians from clinics that had appropriate practices.

Of 150 study participants, only 4 (2.7%) stated that they believed their laboratory practices fulfilled all requirements, 69 (46%) believed their practices were reasonable, and 49 (33%) believed their practices were adequate. Thirteen (8.7%) veterinarians stated that their clinic practices were inadequate and needed improvement, and 14 (9.3%) stated that they did not know enough to say whether their clinic practices were appropriate.

Supervision—Forty of 162 (24.7%) respondents indicated that no one was in charge of the laboratory at their clinics. One person was designated in charge in 43 (26.5%) clinics, and responsibilities were held by > 1 individual in 79 (48.8%) clinics. Various personnel were listed as being in charge in different clinics, including technicians without advanced training in microbiology (n = 74 [45.6%]), veterinarians without advanced training in microbiology (57 [35.2%]), veterinarians with advanced training in microbiology (23 [14.2%]), technicians with advanced training in microbiology (13 [8.0%]), and lay staff (1 [0.6%]).

Continuing education—The majority (138/147 [93.8%]) of respondents stated that continuing education would be useful (Table 4). Areas of interest included general laboratory practices, bacterial identification, antimicrobial susceptibility testing, quality control, and laboratory safety. Veterinarians who described the use of inappropriate disposal practices were less likely (P = 0.016) to indicate a desire for continuing education regarding laboratory biosafety.

Table 4—

Perceptions of the usefulness of continuing education topics as reported by veterinarians who completed an online survey. Data are presented as the number of respondents (%) in each category.

Subject areaNo. of respondentsVery usefulSomewhat usefulNot useful
General laboratory practices14584 (57.9)59 (40.7)2 (1.4)
Bacterial identification14883 (56.1)45 (30.4)17 (11.5)
Antimicrobial susceptibility testing14362 (43.4)52 (36.4)29 (20.3)
Quality control14883 (56.1)56 (37.8)6 (4.1)
Laboratory safety14784 (57.1)59 (40.1)4 (2.8)

Discussion

To the authors' knowledge, this is the first detailed survey of bacteriologic culture facilities and practices in veterinary clinics in several countries. The prevalence of bacterial culture activities among clinics was lower in our study than the prevalence determined in a study in 1985.4 It is unclear whether the difference between these 2 studies is a real change toward a decrease in bacterial culture activities in clinics or is a function of the study population. Regardless, bacterial culture is still a relatively common practice in veterinary clinics. Although the laboratory and biosafety practices reported by some veterinarians were good, there appears to be a substantial number of veterinary clinics in which poor and possibly unsafe laboratory practices were applied. Deficiencies were evident in various areas, including laboratory location, general biosafety practices, culture practices, and supervision.

Most study participants reported that preliminary bacterial isolation was performed at their clinics, with subsequent submission of culture plates to diagnostic laboratories for identification and antimicrobial susceptibility testing of bacteria. This is perhaps the optimal method of in-house culture because expertise and materials for identification and antimicrobial susceptibility testing are not required. Preliminary culture within clinics may save clients money as well as reduce turnaround time for results with respect to specimens that yield no growth; these aspects were apparently the basis of the most common reasons cited for performing bacterial cultures in clinics. Given these benefits, bacterial culture of urine samples was performed at most clinics. Culture of urine is an important aspect of proper diagnosis and treatment of urinary tract disease, and considering the incidence of noninfectious urinary tract disease in some species (eg, cats), the availability of culture results can facilitate prudent decisions regarding antimicrobial treatments. Other reasons for performing bacterial cultures are less justifiable. Fifty-three percent of respondents stated that results are more accurate because shipping of samples is not required. Although survival of bacteria during shipping might be a concern, there is no indication that it is a problem that affects most common opportunist bacterial pathogens in samples collected into conventional transport media for aerobic bacteria. However, it would be of greatest importance for anaerobic and microaerophilic organisms, which were reportedly rarely cultured in veterinary practices. Therefore, this reason is not rational. A desire to be a full-service veterinary clinic was commonly cited, but clinics should not strive to offer a wide breadth of services with inadequate depth and quality, which could be the case with regard to bacterial culture procedures in many clinics. Having an employee with an interest in microbiology sufficient to support development of expertise may be a reasonable factor in deciding whether to perform cultures in clinics because those individuals might be more versed or interested in laboratory quality and safety. However, these individuals would also need adequate infrastructure, personnel, and support to implement appropriate practices. It was therefore surprising to find that clinics with such expertise did not actually use quality control strains in performing antimicrobial susceptibility testing in the present study. At commercial diagnostic laboratories, failure to use quality control organisms in antimicrobial susceptibility testing would be considered a serious methodological error.

Data collected in our study indicated that basic laboratory supplies, such as a purpose-built incubator, were commonly used. However, insulated containers without thermostat-controlled heating were used in some clinics, and it is unclear whether an appropriate and consistent temperature would be maintained in such containers. Considering the relatively low cost of small laboratory incubators, the use of other devices is not justifiable. With standard incubators, it is easy to regularly monitor the temperature, which was periodically (4/156 [2.6%] clinics) or never (4/156 [2.6%] clinics) performed by some veterinarians. Routine recording of incubator temperatures should be an important part of quality control in a clinic laboratory.

Antimicrobial susceptibility testing was performed in 63 of 154 (41%) clinics. It was surprising that approximately 25% (14/58) of veterinarians reported that they used agar dilution testing because this methodology is cumbersome and prepoured media containing various different antimicrobials and concentrations are not readily available commercially. It is likely that most or indeed all respondents selected this in error and were unaware of how their test method should be described; the disk diffusion method would be expected to be used in most or all clinics because of relative ease and low cost. It is of concern to the authors that 19% (12/63) of clinics that reported performing antimicrobial susceptibility testing undertook such testing with only some identification of the organism and that 7.9% (5/63) of such clinics performed susceptibility testing with no attempt to identify the organism. Associated with this was the impression among many veterinarians that identification is not needed for interpretation of results (14/61 [23%] veterinarians) or that only basic identification steps such as results of Gram staining were needed (17/61 [28%] veterinarians). Accurate identification of an isolate is an important step in performing and interpreting results of antimicrobial susceptibility testing. For example, certain organisms are considered inherently resistant to certain antimicrobials (eg, enterococci and cephalosporins) regardless of in vitro results. Failure to understand that concept and accurately identify an isolate could lead to inappropriate patient treatment.

Determination of required biosafety practices involves various factors, including an understanding of the recommended risk group.6 Risk group classification involves the likelihood of organisms to cause disease, their ease of transmissibility in a laboratory situation, the ability to handle the organism safely in a laboratory situation, and the potential severity of disease, among other factors. Risk groups range from 1 (unlikely to cause disease in healthy individuals [ie, Lactobacillus spp]) to 4 (highly virulent, transmissible, and untreatable [ie, Ebola virus]) and must be handled with the corresponding BSL precautions. A general rule is that protocols should be designed to safely handle the highest-risk group pathogens that would reasonably be expected to be isolated from specimens processed in the laboratory. Many organisms that could be isolated from animals are classified as risk group 2, which are considered to be of moderate individual risk (ie, able to cause human disease but under normal circumstances are unlikely to represent a serious hazard to laboratory personnel). Risk group 2 includes many common bacteria such as Escherichia coli, Staphylococcus aureus, and Streptococcus spp. Accordingly, bacterial culture of materials from sites that might harbor risk group 2 pathogens should be performed following BSL 2 practices (Appendix). Although only rather general information on biosafety practices was collected in the present study, it is clear that many, perhaps even most, clinics do not provide adequate BSL 2 containment. Laboratory facility–related factors that were considered inadequate included handling of culture specimens in a nondedicated laboratory, storage and consumption of food in the laboratory area, failure to have appropriate protective clothing requirements, lack of a biohazard sign or sticker displayed in the laboratory area, inability to restrict access to the laboratory, lack of written guidelines, lack of a biosafety manual, and lack of supervision by a person with training in microbiology. The frequency of these deficiencies was striking. Many of these, however, could be addressed with minimal time and effort. The physical laboratory environment is more difficult to modify and could be a limiting factor in determining whether bacterial culture is feasible in some clinics.

The authors found it encouraging that 22% (36/162) of clinics in which bacterial culture was performed had a staff member (a veterinarian or technician) with some form of advanced training in microbiology. A specific definition of advanced training in microbiology was not used in the present study, and it is unclear what study participants considered advanced training because the effect of such training was generally not evident from the survey responses. It is perhaps not surprising that in clinics in which an individual who was trained in microbiology was employed, application of more advanced procedures (eg, bacterial culture of blood) and implementation of certain biosafety protocols (eg, use of appropriate dedicated protective clothing, restriction of access to the laboratory area, and use of appropriate disposal methods) were more likely to be performed. However, in those clinics, it was not more likely that certain quality practices (eg, use of reference strains or posting of required biohazard signage) would be applied. The slightly higher level of laboratory methods and biosafety procedures apparent for clinics in which an individual who was trained in microbiology was employed supports the need for continuing education and training opportunities for people engaged in bacterial culture in clinics. In the present study, the frequent involvement in microbiological procedures of personnel such as lay staff, students, and volunteers was a surprise to the authors and gives cause for concern. Specific questions regarding training of these groups in culture practices and biosafety were not asked; thus, it is unclear whether those individuals were adequately trained from either a quality control or safety perspective. However, it must be assumed that such individuals have little or no background in laboratory practices and biosafety and that unless proper training is provided, there are considerable concerns about professional standards and practice liability resulting from either erroneous results or laboratory infection of personnel.

Methods of disposal of culture plates with visible growth were problematic. Direct disposal of culture plates into regular garbage (performed in 27% [41/150] of clinics) is in clear contravention of biosafety regulations. A further 2% of study participants reported application of disinfectant to plates prior to disposal in the garbage at their clinics. This cannot be considered to be an effective technique because of the variable efficacy of different disinfectants against various pathogens and potential problems with inadequate contact time or penetration of bacterial colonies. Submission of plates with growth to a diagnostic laboratory is a reasonable method provided that proper handling requirements are fulfilled. Methods used to deliver plates to laboratories (ie, laboratory pick-up service or courier) were not evaluated; hence, no conclusions could be made of the adequacy of shipping. Handling of potentially contaminated disposable items (eg, inoculating loops) was also problematic because 47% (69/146) of clinics disposed of such contaminated materials in the garbage. Although this method of disposal is less disturbing for disposable items than it is for culture plates because of a lower level of contamination, this remains an unacceptable practice.

For the authors, it was both encouraging and troubling that only 4 of 150 (2.7%) participants stated that they believed their laboratory practices fulfilled all requirements. The encouraging aspect is the recognition that practices are suboptimal; however, it is disquieting to us that people would allow suboptimal culture procedures to be performed in their clinics despite having concerns. In some situations, the survey respondent may have no control over clinic protocols, and it is unclear whether most of the respondents were decision makers in their clinics.

The interest in continuing education opportunities regarding laboratory practices and biosafety procedures was noteworthy; most survey respondents indicated an interest in these matters. In the present study, many aspects of testing quality could not be specifically evaluated. With regard to bacterial culture, there is an inherent risk of false-positive results (related to contamination or erroneous interpretation of the relevance of commensal microflora), false-negative results (related to poor sample handling, inappropriate medium selection, or inadequate incubation temperatures), and erroneous results (related to misidentification of bacteria or improper antimicrobial susceptibility testing). These are areas of concern because they could have a direct impact on patient care. Therefore, continuing education with regard to general laboratory practices as well as proper bacterial identification, antimicrobial susceptibility testing, and interpretation methods would be valuable. Similarly, continuing education on the subject of laboratory biosafety is required. It was ironic, however, that veterinarians reporting inadequate disposal practices were significantly less likely to consider continuing education regarding biosafety very useful. Whether this indicates a disregard for biosafety or lack of understanding of the issues and their deficiencies is unclear. In addition to continuing education of veterinarians in practice, it is important to consider the education that veterinary students receive. To the authors' knowledge, the level of specific education related to clinical microbiology and laboratory biosafety in veterinary college curricula is uncertain. A survey of 20 North American veterinary colleges performed in 1988 revealed that 65% (13/20) of colleges provided a clinical microbiology rotation for senior students.7 Although all study participants reported that their colleges offered lectures and laboratory sessions in microbiology, the time spent by students in those activities was highly variable, with minimal time commitment required at some institutions. Considering the changes in veterinary medicine over the past 20 years and revisions to veterinary curricula, there is no clear information about current teaching practices with regard to certain aspects of microbiology.

Because the data collected in the present study were derived via a survey that depended on the voluntary participation by members of an online veterinary practice discussion network, it is difficult to know to what extent these data are representative of all veterinary practices. However, the large number of respondents who participated in the study survey, particularly from the United States and Canada, suggests that the data have value as a preliminary assessment of current bacteriologic practices in veterinary clinics. Furthermore, it is possible that the prevalence of bacterial culture in veterinary practices was overestimated because the persons who did not perform bacterial cultures in their clinics were less likely to respond. Regardless, this would not affect the results obtained from veterinarians who reported performing such cultures, which formed the main aspect of the present study.

For the authors, several findings of the present study are disquieting with respect to laboratory practices and biosafety. It is critical that personnel in clinics where culture is performed undertake an assessment of their laboratory practices to determine whether those practices are adequate, both in terms of quality and laboratory safety. Careful review of a basic assessment of whether laboratory practices fulfill appropriate BSL 2 requirements is necessary in each clinic. For some clinics, decisions may need to be made about investment in equipment and time for personnel to upgrade their practices to an acceptable level. It is possible that some clinics may find it difficult (if not impossible) to create a laboratory area that fulfills basic BSL 2 requirements—those clinics may need to discontinue in-house bacterial culture procedures. For other clinics, closer attention to optimal laboratory practices and provision of relevant continuing education may be all that is required. Regardless, it is prudent for veterinary clinics to consider the legal and professional implications of inadequate practices and to ensure optimal patient care and laboratory safety.

ABBREVIATIONS

BSL

Biosafety level

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Appendix

Standard BSL 2 laboratory practices (adapted3,6).

ProtocolsA safety manual must be available to all staff
Protective clothing must be worn by all personnel in the laboratory and not when outside of the laboratory area 
Eye and face protection must be worn in the laboratory area if there is a risk of splashes or flying objects 
Long hair should be tied back when working in the laboratory area 
Eating and drinking are not permitted in the laboratory area 
All staff must receive training on potential hazards and appropriate safety measures 
Storage of food or personal belongings in the laboratory area is not permitted 
Open wounds and cuts must be covered with waterproof dressings 
Gloves must be worn for procedures potentially involving direct contact of skin with biohazardous materials 
The use of needles and other sharp objects must be strictly limited 
Contaminated clothing must be decontaminated prior to laundering 
Hands must be washed with an appropriate antiseptic soap or alcohol-based hand gel at the end of the day and after any potential exposure to biohazardous materials 
Work surfaces must be decontaminated with a suitable disinfectant at the end of the day and after any spill of potentially biohazardous materials 
Prior to removal from the laboratory for servicing or disposal, contaminated items must be decontaminated 
Autoclaves used for decontamination must be regularly monitored with biological indicators 
Leak-proof containers must be used for transportation of biohazardous materials 
Spills, accidents, breaches of containment, and other exposures must be reported to the laboratory supervisor 
Emergency protocols must be in place for events such as spills 
Laboratory facilityDoors to the laboratory area must not remain open and must be lockable
Access to the laboratory area must be restricted and limited to authorized personnel 
The laboratory area must be kept clean and tidy 
Laboratory doors must have appropriate signage 
Work surfaces must be nonabsorptive and scratch, stain, chemical, and heat resistant 
A means of treating waste before disposal must be available 
Separate storage spaces for street and laboratory clothing must be available 
Sinks for hand washing should be readily accessible 
An emergency eyewash station should be available 
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