**1. Introduction**

The emergency services work force, comprising paramedics, police, firefighters, and specialized rescue and response teams, carry out duties on a daily basis that are essential to individual safety and well-being and to the operational functioning of their local community. Beyond these regular, routine activities, emergency medical services also administer life-saving assistance following a critical incident. Against this background, of serious concern is amassing evidence from research case studies to suggest that emergency medical vehicles can act as carriers (so-called vectors) of pathogenic microorganisms, or microbes, thereby promoting human infectious disease transmission [1]. In order to reduce this identified risk, an extensive screening process for pathogens should be performed. Implementation of new or revised policies and procedures would help to safeguard against emergency services crew, equipment and vehicles being inadvertent infectious disease vectors, and so exacerbating the already profound health risks associated with pandemics, natural disasters and bioterrorism.

The contamination of emergency service vehicles with microbes from body fluids or excreta is shown by many recent international studies. This non-systematic review highlights the key findings of selected seminal reports. Raised levels of bacterial species potentially harmful to human health have been detected in a range of emergency medical vehicles and in distinct contexts [2–9]. Notably, ambulances were contaminated with the difficult-to-treat Gram-positive bacterium, methicillin-resistant *Staphylococcus aureus* (MRSA) [2, 3], which is resistant to the commonly used class of penicillin-related antibiotics. In 13 metropolitan ambulances test 49.9% of swab samples showed positive for bacteria; 0.9% were highly drug-resistant pathogenic strains: MRSA; methicillin-resistant coagulase-negative staphylococci (MRCoNS); and carbapenemase-producing *Klebsiella pneumoniae* (KPC) [4]. In a separate study on 21 ambulances, 47.6% of surface swabbings were positive for MRSA [5]. Further, "large numbers of microbes" were isolated from helicopter air ambulances [6], corroborated by more detailed findings from Australia [7]. Microbiological cultures swabbed from four ambulances demonstrated that "four of the seven species isolated were substantial nosocomial pathogens, and three of these four possess formidable antibiotic resistance patterns" [8]. Similarly, 49% of rural ambulances tested positive in at least one internal location for contamination with MRSA [9]. Gram-negative coliforms of a variety of genera including *Enterobacter*, *Klebsiella* and *Escherichia* were commonly detected [3], suggestive of contamination with fecal or soil matter.

Emergency care equipment was discovered to also be a source of contamination. Sphygmomanometer cuffs, stethoscopes and respirator masks in ambulances frequently carried enterococci and *S. aureus* [10]. In one study, 57% of patient-ready trauma equipment swabbed at six hospitals and three regional ambulance services in the UK tested positive for blood contamination [11]. Likewise, of 50 stethoscopes used by paramedics 32% tested positive for MRSA [12].

### **2. Examining emergency medical helicopters for bacterial contamination**

The extent of the problem of bacterial contamination of ambulances is exemplified by a recent proof-of-concept case study that examined two helicopter air ambulances based in separate municipalities in Queensland, the north-eastern state of Australia [7]. Emergency medical helicopters were selected due to the dearth of research on this type of emergency service vehicle as a vector of infection transmission. The two aircraft made a collective 68 call responses over 3 months. These involved patient transfers for specialist care (66.2%), primary responses (23.4%) (including road traffic incidents, cardiac arrest and medical cases), neonatal transfer to or between maternity care facilities (8.8%), and one search and rescue case (1.5%). During the study period samples were collected by swabbing each helicopter on six occasions at approximately weekly intervals. The helicopter's flight log provided for every response details of travel distance, locations of departure, pick-up and destination, and number and role of persons in transit. The presence or absence of bacteria was correlated longitudinally against time with each of geographical location, intra-vehicle surfaces, flight schedules and cleaning timetables.

For each sampling, the helicopter's interior was swabbed in five sites considered by emergency response crew to have a high frequency of contact, either by

**75**

**Figure 1.**

*Contamination of Emergency Medical Vehicles and Risk of Infection to Paramedic First...*

themselves, patients and/or their companions, which thus present a raised risk of microbial contamination (**Figure 1**) [7, 13]. The diagnostic procedures followed were those approved by government regulatory bodies including the US Food and Drug Administration, comprising standard medical microbiology culture methods. These involved incubating the samples in a variety of selective media that differentiate positive bacterial colonies based on a difference in color. For example, after incubation on chromogenic MRSA agar for 24 hours at 35°C MRSA colonies are colored mauve whereas all other colonies appear blue, green or cream [14]. Confirmation of identity as either methicillin-resistant or multi-resistant bacteria was gained by conducting the disk diffusion (Kirby-Bauer) method on Mueller-Hinton agar [15]. This diagnostic screening was performed on all samples to determine the absence or presence of MRSA and multi-resistant *S. aureus*, vancomycin-resistant enterococci (VRE) and carbapenem-resistant enterobacteria (CRE), each of which is acknowledged to be a significant contributor to healthcare-associated infections [16, 17].

*Sites for microbiological swab sampling for detection of bacterial contamination inside a helicopter air ambulance. Following discussions with paramedic staff and pilots five areas of the aircraft (A) were considered to have a high frequency of contact by emergency crew and patients. These locations were: (B) the floor surface between the emergency crew seats and patient stretcher; (C) the seat belt buckle on the emergency crew seats; (D) the hand piece of the Citizens' Band radio; (E) the buttons on the display panel of the cardiac monitor/*

*defibrillator; and (F) the blood pressure cuff storage bag [13].*

*DOI: http://dx.doi.org/10.5772/intechopen.87219*

*Contamination of Emergency Medical Vehicles and Risk of Infection to Paramedic First... DOI: http://dx.doi.org/10.5772/intechopen.87219*

#### **Figure 1.**

*Healthcare Access - Regional Overviews*

gestive of contamination with fecal or soil matter.

used by paramedics 32% tested positive for MRSA [12].

transmission [1]. In order to reduce this identified risk, an extensive screening process for pathogens should be performed. Implementation of new or revised policies and procedures would help to safeguard against emergency services crew, equipment and vehicles being inadvertent infectious disease vectors, and so exacerbating the already profound health risks associated with pandemics, natural disasters and bioterrorism. The contamination of emergency service vehicles with microbes from body fluids or excreta is shown by many recent international studies. This non-systematic review highlights the key findings of selected seminal reports. Raised levels of bacterial species potentially harmful to human health have been detected in a range of emergency medical vehicles and in distinct contexts [2–9]. Notably, ambulances were contaminated with the difficult-to-treat Gram-positive bacterium, methicillin-resistant *Staphylococcus aureus* (MRSA) [2, 3], which is resistant to the commonly used class of penicillin-related antibiotics. In 13 metropolitan ambulances test 49.9% of swab samples showed positive for bacteria; 0.9% were highly drug-resistant pathogenic strains: MRSA; methicillin-resistant coagulase-negative staphylococci (MRCoNS); and carbapenemase-producing *Klebsiella pneumoniae* (KPC) [4]. In a separate study on 21 ambulances, 47.6% of surface swabbings were positive for MRSA [5]. Further, "large numbers of microbes" were isolated from helicopter air ambulances [6], corroborated by more detailed findings from Australia [7]. Microbiological cultures swabbed from four ambulances demonstrated that "four of the seven species isolated were substantial nosocomial pathogens, and three of these four possess formidable antibiotic resistance patterns" [8]. Similarly, 49% of rural ambulances tested positive in at least one internal location for contamination with MRSA [9]. Gram-negative coliforms of a variety of genera including *Enterobacter*, *Klebsiella* and *Escherichia* were commonly detected [3], sug-

Emergency care equipment was discovered to also be a source of contamination. Sphygmomanometer cuffs, stethoscopes and respirator masks in ambulances frequently carried enterococci and *S. aureus* [10]. In one study, 57% of patient-ready trauma equipment swabbed at six hospitals and three regional ambulance services in the UK tested positive for blood contamination [11]. Likewise, of 50 stethoscopes

**2. Examining emergency medical helicopters for bacterial contamination**

The extent of the problem of bacterial contamination of ambulances is exemplified by a recent proof-of-concept case study that examined two helicopter air ambulances based in separate municipalities in Queensland, the north-eastern state of Australia [7]. Emergency medical helicopters were selected due to the dearth of research on this type of emergency service vehicle as a vector of infection transmission. The two aircraft made a collective 68 call responses over 3 months. These involved patient transfers for specialist care (66.2%), primary responses (23.4%) (including road traffic incidents, cardiac arrest and medical cases), neonatal transfer to or between maternity care facilities (8.8%), and one search and rescue case (1.5%). During the study period samples were collected by swabbing each helicopter on six occasions at approximately weekly intervals. The helicopter's flight log provided for every response details of travel distance, locations of departure, pick-up and destination, and number and role of persons in transit. The presence or absence of bacteria was correlated longitudinally against time with each of geographical location, intra-vehicle surfaces, flight schedules and cleaning timetables. For each sampling, the helicopter's interior was swabbed in five sites considered by emergency response crew to have a high frequency of contact, either by

**74**

*Sites for microbiological swab sampling for detection of bacterial contamination inside a helicopter air ambulance. Following discussions with paramedic staff and pilots five areas of the aircraft (A) were considered to have a high frequency of contact by emergency crew and patients. These locations were: (B) the floor surface between the emergency crew seats and patient stretcher; (C) the seat belt buckle on the emergency crew seats; (D) the hand piece of the Citizens' Band radio; (E) the buttons on the display panel of the cardiac monitor/ defibrillator; and (F) the blood pressure cuff storage bag [13].*

themselves, patients and/or their companions, which thus present a raised risk of microbial contamination (**Figure 1**) [7, 13]. The diagnostic procedures followed were those approved by government regulatory bodies including the US Food and Drug Administration, comprising standard medical microbiology culture methods. These involved incubating the samples in a variety of selective media that differentiate positive bacterial colonies based on a difference in color. For example, after incubation on chromogenic MRSA agar for 24 hours at 35°C MRSA colonies are colored mauve whereas all other colonies appear blue, green or cream [14]. Confirmation of identity as either methicillin-resistant or multi-resistant bacteria was gained by conducting the disk diffusion (Kirby-Bauer) method on Mueller-Hinton agar [15]. This diagnostic screening was performed on all samples to determine the absence or presence of MRSA and multi-resistant *S. aureus*, vancomycin-resistant enterococci (VRE) and carbapenem-resistant enterobacteria (CRE), each of which is acknowledged to be a significant contributor to healthcare-associated infections [16, 17].

**Figure 2.**

*Number and type of bacterial colonies recovered at each emergency service helicopter site for successive microbiological sampling periods. Bacterial counts are presented as Log10 of colony-forming units [7].*

#### **Figure 3.**

*Number and type of bacterial colonies recovered from different internal areas of the helicopter at emergency service site A for successive microbiological sampling periods. Bacterial counts are presented as Log10 of colonyforming units [7].*

**77**

*Contamination of Emergency Medical Vehicles and Risk of Infection to Paramedic First...*

The equivalent antibiotic-susceptible organisms were also examined for as an indicator of the potential of the above antibiotic-resistant bacteria to be carried by

Both presumptive MRSA and other colonies were isolated from each helicopter at all but two sampling periods (**Figure 2**). Excluding occasions when selective media plates showed confluent bacterial growth the number of colony-forming units recovered from the two helicopters was similar (15,069 and 14,399). Of the presumptive colonies tested 18.7% were typed as *S. aureus*, 76.0% were determined to be other staphylococci (such as *S. haemolyticus* and *S. epidermidis*), and 5.3% were identified as other genera of bacteria [7]. Inside each helicopter, if separate swab sites were compared to each other or if the same swab site was examined over several sampling periods, various indicators of possible associations became apparent. For instance, typically the helicopter floor recorded a higher bacterial count, and the two-way radio and cardiac equipment comparatively lower counts, than for the other swabbed surfaces. Presumptive colonies were not recovered at all sampling periods, but they were isolated from all swab sites during the entirety of the study (**Figure 3**) [7].

As 94.7% of presumptive MRSA colonies tested were classified as *Staphylococcus* spp. the likelihood of MRSA existing inside emergency air ambulances is substantial.

Previous research has detected MRSA in road-based ambulances in both metropolitan (47.6% of vehicle tests positive) [5] and rural areas (49% positive) [9]. An assortment of equipment used by emergency services crew has also shown frequent contamination [10–12]. Moreover, examination of nasal swabs demonstrated a disconcertingly raised prevalence of MRSA among paramedic first responders, 6.4%, much higher than the 1.5% MRSA colonization rate of the general public [18]. Of further concern, regarding a parallel issue of work-related stress it was reported that "paramedics ranked outbreaks of new and highly infectious disasters highest

The existence of MRSA and multi-resistant *S. aureus* in emergency medical vehicles could pose a threat to the health of patients and their companions during and after the 4.4 and 32 million emergency ambulance responses each year in, respectively, Australia and the USA [20, 21], as well as to the paramedic first responders who work in these vehicles. This type and level of risk applies equally to emergency service crew in all nations worldwide. It would therefore appear that emergency medical helicopters may act as vectors of transmission of potentially deadly pathogens to the multiple thousands of patients that they transport between sites annually. By amplifying the frequency of response calls per vehicle type the implication is equally clear that road-based ambulances may spread infectious disease-causing microbes among the millions of patients that they transfer to and from hospitals each year. More broadly, inadequate infection control measures across all classes of emergency medical vehicle could exacerbate the major impact

on public health of an infectious disease pandemic or bioterrorism event.

This is particularly so given that the prevalence of MRSA among emergency services crew is reported to exceed four times that of the general population [18]. The abundance of microbes recovered in this [7] and a prior study [6] suggests an increased risk of pathogen transfer between the vehicle, emergency services crew, patients and their companions. This serves to stress the need for standardized cleaning protocols as well as high quality staff training for their application.

**3. Infection risks to paramedic first responders and patients**

for fear and unfamiliarity" [19].

*DOI: http://dx.doi.org/10.5772/intechopen.87219*

these vehicles.

*Contamination of Emergency Medical Vehicles and Risk of Infection to Paramedic First... DOI: http://dx.doi.org/10.5772/intechopen.87219*

The equivalent antibiotic-susceptible organisms were also examined for as an indicator of the potential of the above antibiotic-resistant bacteria to be carried by these vehicles.

Both presumptive MRSA and other colonies were isolated from each helicopter at all but two sampling periods (**Figure 2**). Excluding occasions when selective media plates showed confluent bacterial growth the number of colony-forming units recovered from the two helicopters was similar (15,069 and 14,399). Of the presumptive colonies tested 18.7% were typed as *S. aureus*, 76.0% were determined to be other staphylococci (such as *S. haemolyticus* and *S. epidermidis*), and 5.3% were identified as other genera of bacteria [7]. Inside each helicopter, if separate swab sites were compared to each other or if the same swab site was examined over several sampling periods, various indicators of possible associations became apparent. For instance, typically the helicopter floor recorded a higher bacterial count, and the two-way radio and cardiac equipment comparatively lower counts, than for the other swabbed surfaces. Presumptive colonies were not recovered at all sampling periods, but they were isolated from all swab sites during the entirety of the study (**Figure 3**) [7].

As 94.7% of presumptive MRSA colonies tested were classified as *Staphylococcus* spp. the likelihood of MRSA existing inside emergency air ambulances is substantial. This is particularly so given that the prevalence of MRSA among emergency services crew is reported to exceed four times that of the general population [18]. The abundance of microbes recovered in this [7] and a prior study [6] suggests an increased risk of pathogen transfer between the vehicle, emergency services crew, patients and their companions. This serves to stress the need for standardized cleaning protocols as well as high quality staff training for their application.
