This was a cross-sectional and descriptive study conducted in all medical bacteriology laboratories in Togo.

Togo is located in West Africa with an area of 56.600 km². Its population was estimated at 7.886.000 in 2021 [17] .

The health system is organized according to a pyramid structure with three levels (central, intermediate and peripheral). In terms of the availability of public medical bacteriology laboratories, they are much more at the central and intermediate levels of the health pyramid. At the central level, there are four bacteriology laboratories: one per teaching Hospital (Campus, Kara and Sylvanus Olympio) and one at the Institut National d’Hygiène. At the intermediate or regional level, each of the six health regions has a bacteriology laboratory. At the peripheral level, only the districts of Lacs (Aného), Kloto (Kpalimé) and the Hospital of Bè have bacteriology laboratories. Private or confectional bacteriology laboratories also exist in all the health regions of Togo. A national network of laboratories (NNL) for the confirmation of epidemic prone diseases was created on the 25th October 1998 by Order n˚113/98/CAB establishing the NNL. This network includes the national reference laboratory, regional laboratories and district laboratories.

The study was conducted from June to December 2021.

All public and private bacteriology laboratories of Togo (21) were included.

Laboratory staff was chosen by convenience (two laboratory technicians, one laboratory assistant and one secretary). The hands of this laboratory staff were sampled before and after disinfection by washing with water and mild soap. On each work surface (laboratory bench, the doors’ handles, the sink, the microscopes’ mechanical stage, stages controls, adjustments, the staff mobile phone, and the inside of the autoclave) a swab was taken. On the laboratory benches, samples were taken before and after disinfection.

Several variables were exploited. The microbiological quality of surfaces and staff’s hands: presence of germs (Staphylococci, Enterobacteriaceae, Pseudomonas, Streptococci, Enterococci and yeasts) before and after disinfection of the sites. The average number of colonies present on the different surfaces and staff’s hands in colony-forming units (CFU).

Data collection was done by interview, observation of practices, and laboratory measurements.

A questionnaire was designed by the investigators for this study. It was tested during a pilot survey in Greater Lomé. This questionnaire contains 5 sections with 13 items. See the questionnaire in the appendix.

Optical microscopes were used for direct examination and after Gram staining.

Two types of samples were taken using sterile swabs:

Sterile swabs moistened with sterile normal saline (0.9%) were used to collect samples from the palms of both hands of the staff, rotating them momentarily over the entire palm surface and between the fingers. For laboratory technicians and assistants, samples were taken before hands washing and gloves wearing, after removing gloves and washing hands at the end of the manipulation. For the secretary, swabs were taken before and after hands washing with water and mild soap.

Sterile swabs moistened with sterile normal saline (0.9%) were used to sample some at risk surfaces before and after disinfection with bleach (0.5% active chlorine). The rest of the surfaces, were swabbed only before disinfection.

In each laboratory, the swabs collected were immediately plated onto Oxoid, UK branded agar media (Blood Agar, Mannitol Salt Agar, Sabouraud Chloramphenicol Agar, Mac Conkey Agar and Brilliance Chromogenic Medium^TM UTI). The plates were incubated at 37˚C for 24 hours. The identification of the isolated germs was carried by using the morphological characteristics and the Gram control with microscope. The conventional biochemical tests and the Brilliance UTI chromogenic medium were used for the presumptive diagnosis [19] . Isolated colonies were counted on both blood agar and UTI medium with a magnifying glass. The results were expressed as Colony Forming Units (CFU)/swab [20] .

The quality of the media was ensured by sterility and fertility tests using E. coli ATCC 25922 reference strains.

Frequencies and mean colony numbers were calculated. The ANOVA test was used to compare the mean numbers of colonies and the prevalence ratio and 95% confidence intervals were used to compare the frequencies.

A clearance of ethical comity of the Ministry of Health of Togo was obtained prior to the study (N˚027/2021/CBRS of 25/06/2021).

On the laboratory benches, after disinfection with 0.5% bleach solution, there was no growth on the inoculated media.

The staff’s hands remained contaminated despite the washing with soap and water. Before washing, the average number of colonies was 16.7 (min: 0; max: 1000) and after washing this number was 13.6 (min: 1; max: 1050). The difference between the number of colonies observed before and after washing was not statistically significant (p = 0.8). The residual contamination was 3.7%.

The bacteria on the surfaces before disinfection were mainly represented by 51.8% of enterobacteria including Klebsiella spp. Strains of Klebsiella spp are commensal enterobacteria of the digestive and respiratory tracts of animals including humans. In addition enterobacterial are ubiquitous [25] . They are common in faeces and can be an indicator of faecal contamination. The high proportion of enterobacteria is due to the sampling method, according to the literature, the wet swab technique appears to be better at to detect Gram-negative bacilli [26] .

Mobile phones of staff had a significant contamination rate in our study. But this result is lower than those obtained in Ethiopia, France and Nepal with respectively 94.2% (213/226), 94.0% (49/52) and 97.0% (97/100) [27] [28] [29] . This difference could be explained by the fact that our work was carried out during the COVID-19 pandemic, when disinfection measures had been reinforced following awareness-raising and training. Laboratories workers mobile phones can be a potential source of contamination for themselves, the community, their families especially their children who touch their parent’s phones and without washing their hands send them to the orifices (mouth, eyes, nose and ears). In addition, these mobile phones are a potential source of nosocomial infection [10] .

The hand-carried flora was predominantly represented by Staphylococci. After disinfection by washing, we noted a persistence of these germs. Our results are consistent with those obtained in Greece by Tselebonis et al. in 2016 [30] and by Ravaoarisaina et al. (2019) in Madagascar [31] who found the same trend where Staphylococci represented more than 50% of the germs. This predominance of Staphylococci on the hands could be explained by the fact that they are commensal bacteria of the epithelia of humans and animals [32] . Furthermore, Staphylococcus epidermidis is a skin commensal in almost 100% of humans.

During this study, it was noted that all the laboratory benches disinfected with the 0.5% bleach solution did not show any bacterial growth. These results confirm the effectiveness of this biocide or disinfectant, especially when used under the proper conditions as indicated by the manufacturer [12] . They are in agreement with those obtained in Madagascar by Ravaoarisaina et al. in 2019 who showed the sterility of the bleach disinfected benches [31] .

The residual contamination of hands after washing was 3.7%. Our results are in agreement with those obtained in Ireland by Creamer et al., in 2010 where Methicillin-resistant Staphylococcus aureus was isolated from 3% fingertips of healthcare workers’ hands when hand hygiene was performed [33] .

Our study showed less efficacy of hand washing compared to the study conducted in England by Burton et al, in 2011 in which the volunteers hand washing showed a significant reduction of germs (p < 0.001) [34] . These results may be explained by the fact that hand washing and drying techniques were not followed by all staff in our study.

For more than twenty years, most studies have consistently shown poor compliance with hand washing in all healthcare sectors, including sectors considered at risk of nosocomial infections such as intensive care units [32] . Overall, compliance calculated in these studies varies between 20% and 50%. Out of the 50% of people who wash their hands frequently, only 25% do so in accordance with the rules of the art by respecting the techniques [30] .

Laboratory surfaces (door handles, fridges, sinks, microscope coarse adjustment knobs and stages, and staff mobile phones) were not sampled after disinfection, as these surfaces are not routinely disinfected. Nevertheless, this study showed that the 0.5% sodium hypochlorite (bleach) solution was totally effective in disinfecting benches.