Nasopharyngeal carriage, spa types and antibiotic susceptibility profiles of Staphylococcus aureus from healthy children less than 5 years in Eastern Uganda

Abstract

BackgroundStaphylococcus aureus carriage is a known risk factor for staphylococcal disease. However, the carriage rates vary by country, demographic group and profession. This study aimed to determine the S. aureus carriage rate in children in Eastern Uganda, and identify S. aureus lineages that cause infection in Uganda.MethodsNasopharyngeal samples from 742 healthy children less than 5 years residing in the Iganga/Mayuge Health and Demographic Surveillance Site in Eastern Uganda were processed for isolation of S. aureus. Antibiotic susceptibility testing based on minimum inhibitory concentrations (MICs) was determined by the BD Phoenix™ system. Genotyping was performed by spa and SCCmec typing.ResultsThe processed samples yielded 144 S. aureus isolates (one per child) therefore, the S. aureus carriage rate in children was 19.4% (144/742). Thirty one percent (45/144) of the isolates were methicillin resistant (MRSA) yielding a carriage rate of 6.1% (45/742). All isolates were susceptible to rifampicin, vancomycin and linezolid. Moreover, all MRSA were susceptible to vancomycin, linezolid and clindamycin. Compared to methicillin susceptible S. aureus (MSSA) isolates (68.8%, 99/144), MRSA isolates were more resistant to non-beta-lactam antimicrobials –trimethoprim/sulfamethoxazole 73.3% (33/45) vs. 27.3% (27/99) [p < 0.0001]; erythromycin 75.6% (34/45) vs. 24.2% (24/99) [p < 0.0001]; chloramphenicol 60% (27/45) vs. 19.2% (19/99) [p < 0.0001]; gentamicin 55.6% (25/45) vs. 25.3% (25/99) [p = 0.0004]; and ciprofloxacin 35.6% (16/45) vs. 2% (2/99) [p < 0.0001]. Furthermore, 42 MRSA (93.3%) were multidrug resistant (MDR) and one exhibited high-level resistance to mupirocin. Overall, 61 MSSA (61.6%) were MDR, including three mupirocin and clindamycin resistant isolates. Seven spa types were detected among MRSA, of which t037 and t064 were predominant and associated with SCCmec types I and IV, respectively. Fourteen spa types were detected in MSSA which consisted mainly of t645 and t4353.ConclusionsS. aureus carriage rate in healthy children in Eastern Uganda is high and comparable to rates for hospitalized patients in Kampala. The detection of mupirocin resistance is worrying as it could rapidly increase if mupirocin is administered in a low-income setting. S. aureus strains of spa types t064, t037 (MRSA) and t645, t4353 (MSSA) are prevalent and could be responsible for majority of staphylococcal infections in Uganda.

Impact of mass administration of azithromycin as a preventive treatment on the prevalence and resistance of nasopharyngeal carriage of Staphylococcus aureus

“…aureus carriage to that found in an Ethiopian study in 2017 that reported a prevalence of 13% (52/400) among pre-school children [ 19 ]. On the other hand, the rate found in this study was a little lower than that of a Ugandan child population in the same age group with a carriage rate of 19.4% [ 20 ] or in a Ghanaian population where it was 21% [ 21 ]. After mass administration of azithromycin in the community, the prevalence of S .…”

Epidemiology of &lt;i&gt;Staphylococcus aureus&lt;/i&gt; Infections in Kenya: Current State, Gaps and Opportunities

“…Mupirocin resistance in Kenya as reported by the few studies ranged from 0% -18% in comparison with the continental pooled estimate of 14% (0% -49.6%) [40]. High level mupirocin resistance has recently been observed among carriage strains in Uganda [42].…”

“…In Uganda, t645, t4353, t355, t037 and t064 are the most common with t645 and t4353 appearing less frequently in Kenya [42]. Spa types t037 has been associated with HA-MRSA strains while t064 has been linked to CA-MRSA infections in Uganda [42]. Spa types t042 and t044 have been observed in Egypt and Algeria and were not reported in Kenya [8] whereas in Ghana, t355, t084, t10519 and t008 have been the preponderant strains [50].…”

“…There seems to be limited heterogeneity among MRSA strains with ST239/241 (t037) being the dominant strain. In Uganda, t645, t4353, t355, t037 and t064 are the most common with t645 and t4353 appearing less frequently in Kenya [42]. Spa types t037 has been associated with HA-MRSA strains while t064 has been linked to CA-MRSA infections in Uganda [42].…”

Molecular Characterization of Staphylococcus aureus Obtained from Blood Cultures of Paediatric Patients Treated in a Tertiary Care Hospital in Mexico

“…In several studies, MRSA isolates have a greater variety of virulence genes, among which the presence of pvl, tsst and sea stand out, and these are mainly associated with MRSA isolates with SCCmec-IV. [53][54][55][56] The frequency of pvl in MRSA varies from 9-30%; in Iran (9.7%), South Africa (14%), the US (26%), and China (30%). [50][51][52]55 In the current study, we found the pvl gene in four isolates (1.6%), all with SCCmec-IV.…”