Burden of Methicillin Resistant Staphylococcus aureus (MRSA) and associated factors at TASH: Evidence from colonization of Health Care Workers, Administrative staff, Patients and selected inanimate objects.
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Date
2023-12
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Addis Ababa University
Abstract
Background: Methicillin-resistant Staphylococcus aureus (MRSA) are multidrug-resistant
bacteria that are carried harmlessly by humans and also cause severe life-threatening
infections in community and healthcare settings worldwide. MRSA colonization of
hospitalized patients and healthcare workers (HCWs) is a risk factor for transmission of
infection. Furthermore, inanimate objects, such as Mobile phones, hospital gowns, and
other fomites can serve as a reservoir for MRSA. Good knowledge, attitudes, and practices
(KAP) of HCWs towards MRSA sources, colonization, and transmission is a key strategy
for the control of MRSA. In Ethiopia, MRSA is a public health concern and observed rates
of MRSA infections are reported from different parts of the country but molecular based
data are very scarce or absent.
Objectives: This study aimed to determine the burden and associated factors for MRSA
colonization among HCWs, administrative staff, patients and selected inanimate objects at
Tikur Anbessa Specialized Hospital (TASH), Addis Ababa, Ethiopia.
Methods: A prospective and retrospective cross-sectional study was conducted between
June 2018 to September, 2019 that included 588 HCWs and 468 administrative staff. Nasal
swabs and swabs from their mobile phones were collected. Single swab from gown of each
HCW was sampled. Samples from inanimate objects from the hospital were also analysed
for MRSA. Perceived knowledge, attitudes, and practice (KAP) of HCWs were assessed
using a pretested structured questionnaire. In addition, 170 S. aureus stored isolates were
included mainly for molecular testing. All swabs samples were cultured on Mannitol salt
agar and / or blood agar for growth and identification of S. aureus and MRSA were made
by standard biochemical tests and cefoxitin disc methods respectively. Antimicrobial
testing was performed according to CLSI breakpoints and isolates were further tested for
MecA , PVL detection, Spa and MLST typing and WGS. Data were analysed using SPSS
version 20.0 and statistical testing (Chi-square or Fisher’s exact test for categorical
variables) was used to assess the difference between MRSA colonization rate among
different groups, socio-demographic factors, and KAP level. P-value less than 0.05 was
taken Statistically significant.
Results: A total of 588 HCWs were included in this study and 58.4 % of them were female.
The mean age and standard deviation of HCWs were 29.13 ± 6.66 years, The majority of
HCWs were nurses by profession accounting for 49.1 % (289/588) followed by Medical
doctors (28.4 % ) [167/588]. Among 468 administrative staff , 64.1 % of them were
females. The rate of S.aureus isolates were 16.32 % (96/588) and 8.97 % (42/468) for nasal
swabs and 6.46 % (38/588) and 3,85 % (18/468) for mobile phone contamination for HCWs
and administrative staff respectively . For HCWs group the rate of S. aureus isolation from
gowns was 7.48 % (44/588). Overall, 31 isolates (13.02 %) were sensitive to all antibiotics
tested. All isolates were sensitive to rifampicin. About 10 % of isolates including all MRSA
isolates were vancomycin sensitive using Van A and Van B genes detection methods.
Furthermore ,237 isolates were resistant to at least for one drug. Overall there was a
significant difference between drug resistance among MRSA and MSSA isolates (P-value
<0.05). The burden of MRSA nasal colonization among HCWs and administrative staff was
found to be 4.8 % (28/580) and 0.2 % (1/468) respectively. Nurses were most colonized by
MRSA (22/28 total positive) P-value < 0.05). In this study, 2.72 % (16/588) and 1.3 %
(6/468) mobile phones of HCWs and administrative staff were contaminated by MRSA
respectively which are more frequent for nurses and doctors. Importantly ,2.89 % (17/588)
of HCWs gowns were contaminated with MRSA and slightly higher among female HCWs
(p-value >0.05). The proportion of MRSA from stored isolate of mother-child pair and
diabetic patients was 0.24 % (2/846). While 21.73 % (20/92) stored isolates from clinical
samples were MRSA. Overall 53 % (178/336) of S.aureus isolates obtained from nasal,
clinical, mobile, and HCW’s gowns were PVL positive. A significant difference was also
seen between pvl status and source of S.aureus isolates ( P-value <0.05).Genotyping based
on spa typing has resulted in 131 spa types for 189 S. aureus isolates from various sources
of samples, Forty-two spa types (32.06 %) occurred in 2 or more frequencies, while 89 of
them (67.94 %) observed in singleton. The most frequent spa types in this study were t355
which were observed 23 times, followed by t223, t085, t131, and t003. Spa type t701,
t1828, t080, t2235, t2302 and t14805,t314, t380, t3841, t11375, t5338, t14350,t062,
t318 ,t693 and t937 were some of the spa types described in this study. Moreover, spa CC
15 and CC 22 are the most dominant clones observed. MLST Sequence data were available
for 52 representative S.aureus isolates and 31 sequence types (ST) were generated. ST 152
is the most dominant ST accounting 20.3 % (11/ 54) followed by ST 4666, ST 5, and ST
744 each accounted 5.55 % (3/54 for each STs) . ST 80, ST88. ST97 and other STs were
also found. Twenty-four STs are clustered in 5 MLST CCs and CC5, CC8, and CC15 were
the very common clones both for MRSA and MSSA groups. Many spa types are reported
for the first time in Ethiopia. Moreover, 18 S.aureus were characterized by whole genome
sequencing (WGS),and based on the 16 SrRNA sequences, phylogenetic tree were
constructed along with known sequences from the NCBI database. It seems our isolates
were diverse and mostly poorly separated. Based on the average nucleotide identity and
many of our S.aureus isolates from the nasal, gown, mobile phone, and clinical sources
showed high similarity with S.aureus strains identified from various clinical and non-
clinical isolates. In this study, the overall knowledge of HCWs about MRSA prevention and
control was 85.5 % .The majority of HCWs in TASH had a positive attitude towards the
importance of system-wide approach to prevent MRSA in the hospital (95.2 %, 542/ 582).
While 54.68 % of HCWs had a positive attitude and 68.4 % of them had good practice
about MRSA prevention and control measures at TASH.
Conclusion: MRSA nasal colonization and mobile phone contamination of HCWs in
TASH was higher than administrative staff. The presence of MRSA from gowns of HCWs
is a cause for concern. MRSA was also seen from stored isolates of nasal source of patients
and clinical isolates based on Mec A detection. The high rate of pvl among all S. aureus
isolates is worrisome. There is diverse spa and MLST types among S.aureus isolates, t355
and ST 152 were common ST and spa type respectively. Although, HCWs in TASH had
high level of knowledge about MRSA control and prevention, their attitude and practice
score is inadequate. Hence, it is important to implement a system for continuous
surveillance of MRSA in TASH using phenotypic and genotypic methods to take
preventive measures and track changes of intervention. Moreover, concerted efforts are
needed among HCWs, management body and policymakers to avail and regulate personal
protective equipments (PPEs) in a sustained manner.
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Keywords
S.aureus, MRSA, TASH, MLST, WGS, Spa typing, HCWs