The introduction of medical devices for management and treatment of diseases has contributed to the development of HAIs worldwide with the consequence that put the patient in to poor prognosis. The introduction of such devices is not wrong by itself, instead facilitates the medical procedures, but commitment deficit of the medical personnel’s to the infection prevention protocols was significant.
In the present study, almost all (97%) HCWs and Medical students do not follow the standard protocol set to prevent infections in using crucial medical equipment like stethoscopes. This finding is comparable with other previous studies that reported a rate of 97 to 100% [8, 14–17]. On the other hand, Kilic and his colleagues reported relatively low rate of contamination of stethoscopes than this study . There could be a variety of reasons for the differences. However, in the present study there is statistically significant difference between stethoscopes with no disinfection practice and regularly disinfected one’s (p < 0.05). This is in agreement with studies reported by Uneke and his colleagues (14,15).
A total of 85.8% stethoscopes were contaminated; which is consistent with previous studies reported by Zuliani-Maluf et al. (87%) ; Youngster et al. (85.7%) ; Uneke et al. (80.1%) (15), and Uneke et al. (79%) . Whereas Marinella et al.  and wood et al.  reported 100% stethoscope contamination, which is higher than this finding. However, Africa-Purino and his colleagues found that, lower rate (57%) of contamination than the present study . Furthermore; in this study the mean total bacterial count was 1.44 × 104 CFUs/diaphragm. This is higher in comparison with both the standard  and with previous studies reported by Whittington et al. 34.5 CFUs/diaphragm , Wood et al.  190.9 CFUs/diaphragm.
Two hundred fifty-six bacterial species were identified from 151 contaminated stethoscope diaphragms, with a mean of 1.79 species per diaphragm. The mean bacterial species count was lower as compared to (2.5 spp./diaphragm) reported by Miangi and Andriole , and higher than (1 spp./diaphragm) reported by Uneke and his colleagues . Significant number of isolates in our findings is potential pathogens. As other similar studies, it can be possible to conclude that stethoscope diaphragms contamination with these microorganisms may spread leading causative agents of HAIs.
Gram-positive isolates (78.9%) were more frequent than gram-negative isolates (21.1%). This might be because of the direct contact of the stethoscope to human skin flora, which contains mostly gram-positive bacteria. Moreover, the lifespan of gram-negative bacteria is not more than six hours in vitro; the half-life span is less than an hour . However, excessive bacterial colonization on stethoscope diaphragm enables them to remain alive for a longer period exceeding eight hours  whereas, gram-positive bacteria could remain alive for a longer period, even up to months [9, 22].
One hundred thirty three (52%) isolates were potential pathogens, of them 40.6% were gram-negative isolates this is also higher than previous studies [1, 2, 16, 18]. In addition, 53.7% were non-lactose fermenters, which are serious enteric pathogens. However; S. aureus 59.3% was the most common isolate over other potential pathogens isolated (Klebsiella spp., Citrobacter spp., Salmonella spp., Proteus spp., Enterobacter spp., P. aeruginosa and E. coli). Except Salmonella spp., all bacterial species were common isolates in both present and previous investigations of medical equipment and hospital environments [4, 14–16].
In our investigation, we found a significant infestation of Salmonella spp. on nine consecutively surveyed stethoscope diaphragms of HCWs and medical students attending medical ward at the same survey time. In addition, the total colony count was beyond the upper limit; it is too many to count (TNTC) which is not in agreement with previous studies [2, 11, 14, 21, 23]. Excessive colonization on diaphragms might enable them to remain alive for a longer period. The same instance was evident in a study conducted by Youngster and his colleagues in Israel stated that “At the time the study conducted there was an outbreak of Acinetobacter infections in Neonatal ICU; a stethoscope diaphragm that was positive for multidrug resistant Acinetobacter was collected from a resident during her rotation in the unit” . Such incidents may also show the potential danger of a stethoscope in the healthcare setting. The situation may be worse than expected when fueled with the ignorance of the medical professionals to the infection prevention protocols. The minimum survival time of most HAIs pathogenic organisms is about 2–18 hrs on the diaphragm surface of stethoscopes  and the clinicians spend on average less than 15 minutes with each patient, it is likely that stethoscope can serve as a vehicle for the spread of infection serially to the visiting patient in the hospital setting.
Although, S. aureus is a common flora of human skin; it is also well documented fact that S. aureus is a primary causative agent of HAI [24–27]. In addition, it was the most common pathogenic organism isolated from stethoscopes, with a prevalence of 4.2-54% regardless of the difference in setup and sample size in several studies [2, 8, 14–16, 28]. The prevalence of methicillin resistance among the isolates was higher (MRSA 26.6% and MSSA 30.1%). Staphylococci isolates showed high resistance to commonly used β-lactam antibiotics (Penicillins 75%). This is similar to other previous studies reported elsewhere. S. aureus showed the least resistance to Ciprofloxacin in previous studies in the study area, the prevalence was rising from time to time 0% in 2007  to 8% in 2011 , and in this study reported 17.7%.
All P. aeruginosa isolates were resistant to six most commonly used antibiotics in the study area, including Gentamicin, and Trimethoprim-sulfamethoxazole. All the Salmonella spp. isolates were resistant to Gentamicin, Cefotaxime and Ampicillin, and 88.9% to Chloramphenicol. About, 3/4 of the Klebsiella, Citrobacter, Proteus and Enterobacter species were showed the highest resistant to both Ampicillin and Cefotaxime. Except, Citrobacter and Enterobacter spp. all gram-negative bacteria isolates were susceptible to Ciprofloxacin, which was in-line with a study conducted by Uneke et al. [15, 16] and Gebre-Sealssie . Both gram positive and gram negative bateria have higher rates of resistance to different classes of antibitics; eight and seven classes of antibiotics respectively. Most of the antibiotic classes were used as treatment options in the study area. This might limit the therapeutic potions as the spread of these particular isolates goes on in this way and if intervention is not considered.
In our study, all licensed Doctors (Specialist, Resident and General Practitioner) reported they didn’t disinfect their stethoscope regularly. Hence, 98% had contaminated stethoscope diaphragms. This is consistent with the findings of Parmar et al.  and Wood et al., in which none of the doctors disinfect their stethoscopes regularly. All Nurses had the same habit with their colleague doctors. However, in the previous other studies, Nurses reported to have had good thought than doctors [8, 12, 15]. This might be accounted to either the work burden or ignorance of the HCWs to adhere to infection prevention protocols. Like HCWs, 98.1% of Medical students reported they never disinfect the stethoscope before and after auscultating each patient. This is higher when compared to a study conducted by Uneke and his colleagues among Nigerian Medical student which reported 91% . Of HCWs and Medical students attending Medical, Pediatrics, Gynecology, OPD and ICU wards, none of them reported to disinfect their stethoscope regularly. However, only 13.6% from OR and 4.3% from Surgical ward attendants reported that they disinfect their stethoscopes regularly before and after seeing each patient.
About 55% HCWs and Medical students, attending critical care areas like; ICU, OR, Surgical and Maternity wards, reported that, they have no perception about disinfection of the stethoscope. Twenty-four (31.9%) of HCWs and 5.9% Medical students reported lack of adequate and appropriate disinfectant.
Sufficient emphasis on disinfection practices of such unavoidable medical equipment for patient care is mandatory. Lack of focus in the medical curriculum might be the possible reason for the lack of awareness and high degree of contamination. This was also indicated by several other investigators. Similarly our study indicated high contamination rate of stethoscopes with potential pathogens that may cause variety of diseases. These bacterial strains are resistant to commonly used antimicrobial agents. Therefore strict adherence to stethoscope disinfection, and also to infection prevention protocols for possible other medical equipments may minimize hospital acquired infections and ensure improved patient safety in hospital environment.