Antibiotic resistance pattern of methicillin-resistant Staphylococcus aureus and Escherichia coli from mobile phones of healthcare workers in public hospitals in Ghana

Introduction mobile phone plays an essential role in the lives of healthcare professionals in hospitals as far as communication is concerned. However, it can also serve as a source of nosocomial infections. This study aimed at determining the prevalence and antibiotic susceptibility of Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli isolated from mobile phones used by healthcare staff working in three public hospitals in Ghana. Methods in total, 220 swab samples were collected from 110 mobile phones of healthcare workers at a referral and two public tertiary hospitals in Ghana. Direct spreading of swab samples on agar plates was done. MacConkey agar and Baird Parker agar were used to isolate E. coli and S. aureus, respectively. Clinical Laboratory Standard Institute´s guidelines were followed for susceptibility testing, and S. aureus strains resistant to cefoxitin were considered to be MRSA. All E. coli and MRSA isolates were tested for their susceptibility to antibiotics using European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2018 guidelines with its breakpoints. Obtained qualitative data were analyzed by using Microsoft Excel. Results of 110 mobile phones, 78 (70.9%) and 4 (3.6%) were colonized with S. aureus and E. coli, respectively. From the 78 S. aureus isolates, 22 (28%) isolates were MRSA. Fifty percent (50%) (11/22) of the MRSA isolates were multi-drug resistant, of which one isolate was resistant to all antibiotics tested. E. coli isolates had 100 resistances to both ceftriaxone and ceftazidime. Conclusion mobile phones used by healthcare workers in hospitals frequently harbor E. coli, S. aureus, MRSA and may be sources of hospital-associated infections.


Introduction
Staphylococcus aureus and E. coli along with their other species are both communal bacteria and opportunistic pathogens and their infections are common in low and middle income countries [1]. Approximately 30% of the human population is colonized with S. aureus [2] and the risk of developing this infection is increased in healthcare settings. In an estimate of every 100 hospitalized patients at any given time, seven in high-income and ten in low and middle income countries will acquire at least one hospital infection [3]. Methicillin-resistant S. aureus (MRSA) has emerged as a virulent pathogen and a leading cause of nosocomial infections [4], accounting for 20% to 80% of nosocomial infections [4]. Of current clinical concern, is the prevalence of multidrug resistant MRSA in many parts of the world. In the United State (US), more than 40% of S. aureus blood stream infections are caused by MRSA [5]. In Europe, it ranges widely and the rates in the Mediterranean and United Kingdom (UK) exceed 30%, while the Netherlands and Scandinavian countries are approximately 2% [6]. Sources of these infections in hospitals include medical staff or colonized healthcare workers, colonized patients or patients´ own flora, contaminated environmental surfaces, and inanimate hospital objects [7]. Healthcare workers are increasingly exposed to colonized patients and, hence, more likely to be colonized with such infections than any ordinary person in the general population [8,9].
Several studies on clinicians´ mobile phones contamination in the USA and UK reported a level of overall mobile phone contamination (pathogenic and non-pathogenic organisms) ranging from 75% to 96%, with between 9% and 25% Methicillin-resistant S. aureus (MSSA), MRSA, E. coli [10,11]. E. coli, MRSA, and other virulent pathogens have been isolated from clinicians´ mobile phones; 98.6% MRSA has been detected from phones, hands, and ears of clinicians [11,12]. E. coli has been widely used as an indicator of fecal contamination instead of total coliform, which is more general and may include other environmental isolates. Therefore, E. coli was isolated as an indicator organism in this work to check if healthcare workers were practicing good hand hygiene. Little or no research has been conducted to assess bacteria on health workers´ mobile phones in Ghana. A previous study conducted by Saba et al. [13] assessed pathogens on door handles and other points of contact at the same hospitals considered in this study. The extent of knowledge about the potential of mobile phones to transmit infections among healthcare workers in Ghana was not known. This study, therefore, aimed at determining the antibiotic resistant profiles of S. aureus, Methicillin-resistant S. aureus (MRSA) and of E. coli isolates from mobile phones used by healthcare workers in three public hospitals in Ghana.  ). Similarly, antibiotic susceptibility tests were also performed on the positive of E. coli and the MRSA isolates using the EUCAST, 2018 guidelines with its breakpoints. The antibiotics disks used for the E. coli isolates were ciprofloxacin (5 µg), gentamicin (10 µg), erythromycin (15 µg), ceftriaxone (30 µg), ceftazidime (10 µg) and nitrofurantoin (100 µg). For the susceptibility test of the MRSA isolates, the antibiotic disks used were ciprofloxacin (5 µg), gentamicin (10 µg), erythromycin (15 µg), tetracycline (30 µg), and chloramphenicol (30 µg). Multi-drug resistant isolates were classified as resistance to three or more antibiotics. All isolates have been stored in 25% glycerol at -20°C, and are available for future studies.

Methods
Statistical analysis: data obtained were analyzed using Microsoft Excel (Microsoft Office 2016). Results were enumerated in frequencies and percentages and presented in tables and charts.

Results
Sources of S. aureus and E. coli: a total of 78 S. aureus isolates were cultured from 78 (70.9%) phones of the 110 mobiles phones sampled. Of the 78 S. aureus 58% (29/50) were from TTH, 80% (24/30) from TWH and 83% (25/30) from TCH (Table 1). Among the 110 samples collected for the isolation of E. coli from the 110 different mobile phones, there were no mobile phones contaminated at TWH and TCH, but 8% (4/50) of mobile phones from TTH were contaminated with E. coli. The phones contaminated with E. coli were found on mobiles phones of personnel from the following wards: administration, children´s, medical, and male wards. All mobile phones contaminated with E. coli were also contaminated with S. aureus Determination of methicillin-resistant (MSRA) and methicillin-sensitive (MSSA) isolates using cefoxitin: antibiotic susceptibility tests were performed on the 78 positive S. aureus samples. Of the total 78 positive S. aureus isolates, 28% (22) isolates were resistant to cefoxitin while 72% (56) were susceptible. Twenty-eight percent (28%) of the isolates were, therefore, considered as MSRA while 72% were classified as MSSA. Of the 28% MRSA isolates, 45% (10), 41% (9), 14% (3) were from TTH, TCH and TWH, respectively ( Table 2). Table 3 shows the wards in the various hospitals where MRSA were isolated.
Antibiotic resistance profile of MRSA isolates: fifty percent (11/22) of the MRSA isolates from the mobile phones were multi-drug resistant MRSA. One MRSA isolate, which was taken from a mobile phone on the female ward of the TCH, was resistant to all the five antibiotics (ciprofloxacin, gentamicin, erythromycin, tetracycline, and chloramphenicol) while another isolate, which was taken from the children´s ward of TCH, was resistant to four (gentamicin, erythromycin, tetracycline, and chloramphenicol) out of the five antibiotics tested (Table 4). Nine (9) of the 22 isolates were resistant to three antibiotics of which four were from the TTH (administration block, children´s, female and maternity wards), four from the TCH (administration block, OPD, male and labor wards) and one was from TWH (children´s ward) ( Table 4). Six (27.3%) of the isolates were resistant to two antibiotics and three (13.6%) isolates were resistant to only one antibiotic. Twenty (90.9%) of the isolates were resistant to one or more antibiotics, while two isolates were susceptible to all the antibiotics used. Only one MRSA isolate (4.5%) was resistant to ciprofloxacin, two (9%) isolates were resistant to gentamicin, fourteen (63.6%) isolates were resistant to tetracycline, sixteen (72.72%) isolates were to erythromycin, and eighteen (81.82%) isolates were resistant to chloramphenicol. The highest resistance was recorded against chloramphenicol and the least was ciprofloxacin (Table 4). In Table 4 below shows the resistant profile of the MRSA and various hospital sources.
Antibiotic resistance pattern of the E. coli isolates: antibiotic susceptibility tests were performed on the four (3.4%) positive E. coli isolates using six different antibiotics (ciprofloxacin (5µg), gentamicin (10µg), erythromycin (15µg), ceftriaxone (30µg), ceftazidime (10µg) and nitrofurantoin (100µg). None of the isolates was exhibited multi-drug resistance. The resistant pattern can be found in Table 5. All the four (100%) isolates were resistant to both ceftriaxone and ceftazidime.

Discussion
Our results provide an essential informative baseline on S. aureus, E. coli and MRSA on mobile phones belonging to healthcare workers of these hospitals in Ghana. There have been previous reports on the possibility of pathogens transmissions, not only by mobile phones, but also other electronic devices such as personal digital assistants, handheld computers, stethoscopes, which also included some epidemiologically important drug-resistant pathogens [16]. High level of S. aureus colonization in this study could be as a result of improper hand hygiene practice and irregular sensitization of mobile phones by these health workers as they come into contacts with colonized patients, surfaces, objects, and other objects in the hospital environments. This is in accordance with Katsuse-Kanayama et al. [17] and reinforces the need for proper hand hygiene practice by healthcare workers prior to patient contact as a critical way of avoiding healthcareassociated infections. Though the rate of E. coli contamination was low in our study, it is higher than the rates (0.98%) reported by Morubagal et al. [18] but similar to Rana et al. [19], where they reported 2%. Conversely, Tagoe et al. [20], Selim and Abaza [21], and Debnath et al. [22] had little higher rates of 8%, 13% and 14%, respectively. Contamination with E. coli means that other fecal coliforms and pathogens from healthcare workers´ mobile phones could be transmitted onto their hands and subsequently to the patients they serve or other common contact surfaces in the hospitals.
The MRSA isolation rate found in this study (28%) is higher than similar researches carried out. Oguzkaya-Artan et al.
[23] recorded 0.95% rate of isolation in Turkey, 1.4% by Heyba et al. [24] in Kuwait, 11.7% by Smibert et al. [25] in Australia, and 13% by Pal et al. [26] in the UK. However, other researchers reported higher isolation rates such as 53% by Selim and Abaza [21] in Egypt, 37.5% by Chang et al. [27] in Taiwan, 73% by Iyer et al. [9] in Saudi Arabia, 33.9% by Shibabaw et al. [8] in Ethiopia and 53.3% by Angadi et al. [28] in India. Fifty percent (11/22) of the MRSA isolates from the mobile phones were multidrug resistant MRSA isolates (Table 4). It is worrisome to find that an isolate from one of the mobile phones was resistant to all the antibiotics tested. There is a risk of resistant microbes and genes being possibly transferred to healthcare workers or patients. This could pose an increased financial burden on patients with low income status. These patients may be forced to resort to other advanced line antibiotic treatments, which are more expensive. Other previous studies did record higher percentages of E. coli contamination on mobile phones than our work [12,29]. Per the phenotypic resistance pattern, they may be similar or the same strains, but further work needs to be done to ascertain it. The presence of faeces on mobiles phones may be due to lack of cleanliness and low hygiene standards [22].
The antibiotic resistance profile of our study showed no multi-drug resistance (i.e. resistance to three or more antibiotics), but all the E. coli isolates were 100% resistant to both ceftazidime and ceftriaxone unlike other studies where they recorded 42.9% resistance to ceftazidime [22] and 50% resistance to ceftriaxone [18]. Our study also recorded 100% susceptibility to ciprofloxacin, gentamicin, erythromycin and nitrofurantoin but Debnath et al. [22] reported 42.9% and 57.1% resistance to both gentamicin and ciprofloxacin respectively in Bangladesh, and Morubagal et al. [18] reported 50% resistance to ciprofloxacin in Iran. However, our study had similar results with Gashaw et al. [30] who found E. coli isolates from healthcare workers´ mobile phones to be 100% sensitive to ciprofloxacin and gentamicin. On two of the mobile phones, both E. coli and MRSA were isolated. One mobile phone had ceftriaxone and ceftazidime resistant E. coli and erythromycin, tetracycline and chloramphenicol resistant MRSA. The other mobile phone had E. coli resistant to ceftriaxone and ceftazidime, but the MRSA isolate from it was susceptible to all the antibiotics used. Further molecular characterization of these strains is required to understand the resistance dynamics, which was a limitation of this particular research.
Limitations of the study: it would have been relevant to extend the study to smaller and/or private hospitals. This study was limited to public hospitals at Tamale metropolis. Careful consideration should be taken to avoid generalizing the findings to all hospitals in Tamale metropolis. Data limitation on sample size was a major obstacle, especially from Ghana. The researchers used journals for information on Africa, and relied on the little available literature that was available for estimation. The study employed conventional approach instead of molecular (PCR) methods that are known to be highly specific. To overcome this, Baired Parker supplemented with Rabbit Plasma Fibrinogen (RPF) which makes it highly selective for S. aureus isolation, and use of biochemical confirmation were employed for the study.

Conclusion
This study is the first to focus on contamination of healthcare workers´ mobile phones with E. coli and S. aureus in Ghana. In three hospitals in Tamale, health worker´s phones recorded very low colonization of E. coli but there was high prevalence with S. aureus exhibiting relatively high rates of MRSA that presented various resistance patterns to the antibiotic used in the study. Health workers´ mobile phones may serve as a source of transmission of MRSA to patients. Awareness creation on the potential for mobile phones to spread diseases in the hospital setting, alongside with intensive programs on infection prevention and control in hospitals, is recommended.