Gross contamination of the transport environment

Only 2 studies presented data on gross contamination of ambulances. In a 2018 online survey of Australian paramedics, 32.4% of respondents often or always worked in a visibly dirty ambulance and 96.4% found blood contamination on equipment, supplies, and other surfaces in an ambulance at the beginning of a shift >3 times per year.^{Reference Barr, Holmes, Roiko, Dunn and Lord3} In a 2006 cross-sectional study of ambulance equipment ready for patient use in 6 UK emergency departments, 15% of equipment was grossly contaminated with blood despite being designated ready for patient use, and a further 42% of equipment tested positive for blood with the Kastle-Meyer test, which evaluates blood contamination not seen by the naked eye.^{Reference Lee, Levy and Walker4}

Common bacteria in the transport environment

Table 1 presents data from 12 studies that describe the flora encountered in medical transport environments in 7 different countries between 2003 and 2018. Medical transport environments were shown to be contaminated by clinically significant bacteria such as Staphylococcus aureus,^{Reference Teter, Millin and Bissell5–Reference Vikke and Giebner10} Pseudomonas spp,^{Reference O’Hara, Reed and Afshinnekoo7,Reference Galtelli, Deschamp and Rogers11–Reference Nigam and Cutter13} Klebsiella spp,^{Reference O’Hara, Reed and Afshinnekoo7,Reference Alves and Bissell12,Reference El-Mokhtar and Hetta14} Enterococcus spp,^{Reference Varona-Barquin, Ballesteros-Peña and Lorrio-Palomino6–Reference Vikke and Giebner10} Staphylococcus epidermidis,^{Reference Alves and Bissell12} and Streptococcus viridians.^{Reference Alves and Bissell12} The clinically significant fungi Aspergillus was also reported.^{Reference Luksamijarulkul and Pipitsangjan15} In addition, 9 studies reported on drug-resistant bacteria in the transport environment (Table 2). These studies reported the presence of methicillin-resistant Staphylococcus aureus (MRSA),^{Reference O’Hara, Reed and Afshinnekoo7,Reference Vikke, Giebner and Kolmos9,Reference Gibson16–Reference Noh, Shin and Kim20} vancomycin-resistant enterococci (VRE),^{Reference Teter, Millin and Bissell5,Reference Vikke, Giebner and Kolmos9} extended-spectrum β-lactamase (ESBL)–positive Klebsiella pneumoniae,^{Reference Noh, Shin and Kim20} imipenem-resistant gram-negative rods,^{Reference Alves and Bissell12} and methicillin-resistant coagulase negative Staphylococcus spp.^{Reference Noh, Shin and Kim20} Notably, a study of oxygen cylinders in ground ambulances and an off-site oxygen cylinder storage area showed that 100% and 96% of the oxygen cylinders were colonized with MRSA at each site, respectively.^{Reference Gibson16}

Table 1.

Commonly Found Microbes and Contaminated Locations by Study

Note. BP, blood pressure.

Table 2.

Drug-Resistant Bacteria and Commonly Contaminated Locations by Study

Note. BP, blood pressure. ECG, electrocardiogram; MRSA, methicillin-resistant Staphylococcus aureus; VRE, vancomycin-resistant enterococci; ESBL, extended-spectrum β-lactamase.

Commonly studied equipment and ambulance locations

Six studies reported the percentage of swabs that were positive for potentially pathogenic bacteria based on the type of equipment and ambulance location (Table 3). Stethoscopes and blood-pressure cuffs were the most frequently evaluated equipment. Specifically, studies in Egypt and the United States have reported that 67.7% and 32% of samples from stethoscopes were contaminated, respectively.^{Reference El-Mokhtar and Hetta14,Reference Gibson16} Similarly, 2 separate studies in Denmark conducted in 2016 and 2018 reported that 12% and 18% of blood-pressure cuff samples were contaminated, respectively.^{Reference Vikke and Giebner8,Reference Vikke, Giebner and Kolmos9} In a 2018 study from Denmark that also evaluated separate parts of EMS provider uniforms, swabs collected from uniform torsos and uniform sleeves were contaminated 24% and 21% of the time, respectively.^{Reference Vikke, Giebner and Kolmos9}

Table 3.

Commonly Contaminated Equipment in the Medical Transport Environment

Contamination and colonization of EMS personnel

In a 2015 prospective observational study, providers had S. aureus (4.84%), VRE (1.61%), and Acinetobacter spp (4.84%) on their hands before performing hand hygiene.^{Reference Teter, Millin and Bissell5} Of all organisms, most data pertaining to EMS personnel have been related to MRSA. In 3 studies performed in the United States from 2013 to 2016, EMS personnel had nasal MRSA colonization (Table 4). In a 2016 cross-sectional study of randomly sampled EMS personnel from 84 urban and rural agencies in Ohio, 4.6% of EMS personnel sampled were colonized with MRSA compared to a national MRSA colonization rate at the time of data collection between 1.5% and 2%.^{Reference Orellana, Hoet and Bell21} A 2013 cross-sectional study of 2 fire departments showed a 6.4% prevalence of nasal MRSA colonization in EMS personnel compared with a 1.5% prevalence among the general population.^{Reference Al Amiry, Bissell, Maguire and Methicillin-Resistant22} Finally, a 2013 prospective study of out-of-hospital care providers and EMT students revealed a MRSA nasal colonization rate of 4.5% compared with the reported rate for the US population at the time of 0.084%.^{Reference Miramonti, Rinkle and Iden23}

Table 4.

Reported MRSA Colonization of EMS Personnel

Note. MRSA, methicillin-resistant Staphylococcus aureus.

Colonization of transport patients

In a 2004 prospective cohort study of patients hospitalized in a foreign country and repatriated to a hospital in their home country by international air transport on scheduled airlines or ambulance, MRSA, Acinetobacter baumanii, and multidrug-resistant K. pneumoniae colonization were observed in 3%, 2%, and 2% of patients, respectively.^{Reference Fischer, Veldman, Diefenbach and Schäfer24} In a 2012 retrospective observational study of patients transported via ambulance in Korea, interfacility transport ambulance patients had significantly higher odds of Mycobacterium tuberculosis (ie, TB), MRSA, and VRE colonization than nonambulance patients, and prehospital ambulance patients had significantly higher odds of MRSA and VRE than nonambulance patients.^{Reference Ro, Shin, Noh and Cho25}

EMS personnel hygiene perceptions and barriers

Our review included 4 studies that evaluated EMS personnel hygiene perceptions and barriers. In a 2018 online survey of self-reported behaviors and perceptions of Australian paramedics, 98.3% of participants agreed that cleaning an ambulance or shared medical equipment was part of their duties and that 89.4% believed that poor cleanliness increased the risk of transmission of HAI.^{Reference Barr, Holmes, Roiko, Dunn and Lord3} Among these respondents, 90.1% cited operational pressure or the impression of too much to do in the time allowed between patient cases; 69.3% cited being directed to respond to another patient case rather than perform routine cleaning; and 76.5% cited lack of appropriate cleaning equipment or products as barriers to cleaning.^{Reference Barr, Holmes, Roiko, Dunn and Lord3}

In a 2019 cross-sectional study of self-reported hand hygiene (HH) perceptions and compliance among EMS providers in Denmark, 98% of providers perceived the preventative effect of HH on HAI, 98% believed that HAI influences patient outcomes, and 92% believed that HH is important to their patients, yet only 47% believed that HH was important to their managers.^{Reference Vikke, Vittinghus and Betzer26} Furthermore, respondents believed that access to supplies at the point of care, support from their managers, simple and clear instructions, and education and training would improve their compliance 94%, 71%, 77%, and 70% of the time, respectively.^{Reference Vikke, Vittinghus and Betzer26}

A 2012 cross-sectional study of the outcomes of a pilot program was conducted to promote HH at a suburban fire department in Florida. The program included brief HH training, installation of hand-rub stations, and posting HH reminder signs. The results showed that forgetfulness (28.9%), difficulty finding water or hand rub (11.6%), belief that wearing gloves was a substitute for HH (8%), and fatigue (2.7%) were barriers to HH.^{Reference McGuire-Wolfe, Haiduven and Hitchcock27} After the intervention, 24% strongly agreed that installation of alcohol-based hand-rub dispensers and signs led to more frequent HH; 58.8% strongly agreed that the hand-rub dispensers in the rescue vehicle increase the likelihood that they will clean their hands during and after patient care; and 28.1% strongly agreed that the HH signs in the station helped them remember to clean their hands.^{Reference McGuire-Wolfe, Haiduven and Hitchcock27}

In a 2019 qualitative study of both prehospital and interfacility EMS providers in Saudi Arabia, providers washed their hands after patient contact more than before patient contact because they were more concerned about themselves getting sick than transmitting disease to their patients.^{Reference Khan28} Some providers also reported they do not comply with HH because they believe that their prior history of not getting sick will protect them from getting sick moving forward.^{Reference Khan28}

EMS personnel hand hygiene adherence

In our review, 9 studies reported on hygiene adherence among EMS personnel and five of these studies presented HH findings specifically (Table 5). Overall, the studies demonstrated low adherence to HH before patient contact, ranging between 1.1% and 34%. They also showed that EMS personnel perform HH after patient contact, ranging between 54% and 87.6%.

Table 5.

Results from Observational Studies Evaluating Hand Hygiene (HH) in EMS Providers

Note. NR, not reported.

^a Represents HH in the emergency department after dropping patient off.

^b Represents arrival in the emergency department wearing gloves.

In a study conducted in suburban Florida, 94% of EMS personnel reported that they consistently practiced HH when returning to the station after a call and after transporting a patient.^{Reference McGuire-Wolfe, Haiduven and Hitchcock27} Another study conducted in Denmark showed that the median self-reported HH compliance rate was 80%.^{Reference Vikke, Vittinghus and Betzer26} In contrast, another study showed that 13% always performed HH before every patient contact but 12% never performed HH before contact with patients; 67% performed HH after patient contact every time; and 52% used gloves every time.^{Reference Bucher, Donovan, Ohman-Strickland and McCoy29} In a 2011 cross-sectional survey of EMS professionals during the 2007–2008 influenza season, 47.9% reported receiving influenza vaccination.^{Reference Hubble, Zontek and Richards30}

EMS personnel disinfection adherence

Among the 34 studies included in this review, 4 studies presented data on EMS personnel adherence to ambulance and equipment disinfection. In a 2014 prospective observational study of EMS providers who transported patients to a large urban emergency department in Las Vegas, Nevada, low disinfection frequencies were reported for common ambulance equipment: 55% for stretchers, 31.6% for backboards, 33.8% for ECG monitors, 36.5% for ECG cables, 4.1% for stethoscopes, and 33.3% for the ambulance.^{Reference Bledsoe, Sweeney, Berkeley, Cole, Forred and Johnson31} In a 2018 cross-sectional study of EMS providers in Denmark, adherence to guidelines regarding thorough cleaning of the ambulance once per day was 35%, but adherence was 100% for moderate cleaning of the ambulance after every patient course.^{Reference Vikke, Giebner and Kolmos9}

In a 2015 cross-sectional self-reported online survey, 22% of EMS personnel cleaned equipment after every patient contact and their stethoscopes were cleaned 13% of the time.^{Reference Bucher, Donovan, Ohman-Strickland and McCoy29} In a 2009 prospective, observational cohort study of 50 stethoscopes provided by consecutive EMS providers at an academic emergency department, 32% had no recollection of when they had last cleaned their stethoscope.^{Reference Merlin, Wong and Pryor18}