Molecular epidemiology of Panton-Valentine Leukocidin-positive community-acquired methicillin resistant Staphylococcus aureus isolates in pastoral communities of rural south western Uganda

Abstract

BackgroundThe emergence of multidrug resistant Staphylococcus aureus strains, including methicillin resistant (MRSA), is a global concern. Treatment of bacterial infections in Uganda’s health care settings is largely empirical, rarely accompanied by laboratory confirmation. Here we show the burden, characteristics of MRSA and epidemiology of Panton-Valentine Leukocidin (PVL) positive strains in asymptomatic carriers in pastoral households of south-west Uganda.MethodsNasal swabs from 253 participants were cultured following standard methodology. MRSA strains were identified by detection of the mecA gene and SCCmec typing, and PVL genes detected by PCR. Pulsed Field Gel Electrophoresis (PFGE) was done to evaluate possible transmission patterns. Spa typing of PVL positive isolates was done to study the epidemiology of virulent strains in this setting.Results S. aureus was isolated in 29% (n = 73) of the participants, of which 48 were MRSA by mecA typing. PVL-encoding genes were found in 49.3% (n = 36) of the 73 isolates, of which 25 were also mecA positive. Among the PVL negative strains (n = 37), 62.2% (n = 23) carried the mecA gene. The most common SCCmec type was V, detected in 39 (18 PVL positive and 21 PVL negative) isolates. PFGE clustered 21/36 (58.3%) PVL positive isolates divided in four pulsotypes and 18/37 (48.6%) PVL negative isolates divided in eight pulsotypes. The most prevalent Spa types were t318 (26.5%, n = 9) and t645 (20.6%, n = 7); while other common Spa types were t11656 (n = 3), t127 (n = 3) and t355 (n = 3).ConclusionThe study shows a high prevalence of community acquired (CA)-MRSA, and PVL-positive isolates with two predominant spa types in rural Uganda, further complicating infection control strategies in these underprivileged communities.

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

“…Briefly, PCR products were purified with QIAquick PCR purification kit (Qiagen) and sequenced at MBN Laboratories (Kampala, Uganda) or ACGT Inc. (Wheeling, IL, USA) using forward and reverse primers used in the PCRs. To obtain spa types, sequences were submitted to an online spaTyper server http://spatyper.fortinbras.us/ and confirmed by cross-checking the repeats with the Ridom Spa Server http://spaserver2.ridom.de/spatypes.shtml To identify S. aureus lineages that are likely to cause infection in Uganda, we compared spa types for S. aureus at the IMHDSS to previously described spa types at Mulago Hospital in Kampala [9], as well as pastoral communities in Western Uganda [17,18].…”

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

“…The exception is t4353, which appears to be common in Uganda and other settings in East Africa [9, 18,35] but rare in other African countries [42,48] Study flow chart illustrating the procedure for the isolation and identification of S. aureus…”

“…Briefly, PCR products were purified with QIAquick PCR purification kit (Qiagen) and sequenced at MBN Laboratories (Kampala, Uganda) or ACGT Inc. (Wheeling, IL, USA) using forward and reverse primers used in the PCRs. To obtain spa types, sequences were submitted to an online spaTyper server http://spatyper.fortinbras.us/ and confirmed by cross-checking the repeats with the Ridom Spa Server http://spaserver2.ridom.de/spatypes.shtml To identify S. aureus lineages that are likely to cause infection in Uganda, we compared spa types for S. aureus at the IMHDSS to previously described spa types at Mulago Hospital in Kampala [9], as well as pastoral communities in Western Uganda [17,18].…”

Molecular Analysis and Integron Carriage of Mupirocin-Resistant Staphylococcus aureus Strains Isolated from Burn Wound Infections, Tehran, Iran

“…Total genomic DNA was extracted from an overnight pure culture of S. aureus strains on 5% sheep blood agar (BA; Merck, Germany) by using phenol-chloroform extraction. Briefly, one to five bacterial colonies were suspended in 100 µL of lysis solution containing 1% Triton and 20 µL of 1 mg/mL lysostaphin (Sigma-Aldrich, USA) as recommended by Asiimwe et al (13). The purity of DNA was measured by using NanoDrop (Thermo, USA).…”