Eur J Clin Microbiol Infect Dis DOI 10.1007/s10096-015-2387-9
ARTICLE
Staphylococcus aureus nasal carriage among healthcare workers in Kisangani, the Democratic Republic of the Congo H. De Boeck 1 & S. Vandendriessche 2 & M. Hallin 2,3 & B. Batoko 4 & J.-P. Alworonga 4 & B. Mapendo 4 & C. Van Geet 5 & N. Dauly 4 & O. Denis 2 & J. Jacobs 1,6
Received: 25 February 2015 / Accepted: 8 April 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Methicillin-resistant Staphylococcus aureus (MRSA) is a global health concern, but there are few data from Central Africa. The objective of our study was to characterise S. aureus colonisation isolates from healthcareexposed professionals in the Democratic Republic of the Congo (DRC). Healthcare workers and medical students (n=380) in Kisangani, DRC were screened for S. aureus nasal carriage in a single-centre cross-sectional study in the University Hospital of Kisangani. The isolates were identified and characterised using phenotypic and genotypic methods. The nasal carriage rate of S. aureus was 16.6 % and 10 out of 63 isolates (15.9 %) were MRSA. We found 28 different spa types. Most MRSA isolates belonged to ST8-spa t1476-SCCmec V. The majority of MRSA were
HDB and SV equally contributed to the present study and share first authorship. * H. De Boeck [email protected]
multidrug-resistant to non-beta-lactam antibiotics. Overall, 28.5 % of S. aureus carried Panton–Valentine leucocidin (PVL)-encoding genes (all methicillin-sensitive) and 17.5 % carried toxic shock syndrome toxin-1 (TSST-1)encoding genes. The finding of MRSA carriage among healthcare workers in a setting with limited access to diagnostic microbiology and appropriate therapy calls for improved education on infection control practices and supports the introduction of surveillance programmes.
Introduction Staphylococcus aureus is amongst the most frequent organisms affecting man. In many African countries, methicillinresistant S. aureus (MRSA) appear to be on the rise, but studies are scarce for sub-Saharan Africa (SSA), particularly Central Africa [1, 2]. The anterior nares are the primary colonisation site of S. aureus and S. aureus carriage is a known risk factor for S. aureus infection [3, 4]. The strain causing infection is usually also the nasal carriage strain [5]. In this regard, MRSA carriage is of particular relevance among healthcare workers (HCW), who may play a causal role in MRSA crosstransmission to patients [6]. The present study aimed to characterise S. aureus colonisation isolates from healthcareexposed professionals in the Democratic Republic of the Congo (DRC).
1
Department of Clinical Sciences, Institute of Tropical Medicine (ITM), Nationalestraat 155, 2000 Antwerp, Belgium
2
Centre National de Référence MRSA Staphylocoques, Microbiology, Hôpital Erasme—Université Livre de Bruxelles, Lennikse Baan 808, 1070 Anderlecht, Belgium
3
Centre de Diagnostic Moléculaire iris-Lab, Hôpital SaintPierre—Université Libre de Bruxelles, Rue Haute 322, 1000 Brussels, Belgium
4
Department of Pediatrics, University Hospital Kisangani, Kisangani, Democratic Republic of the Congo
Materials and methods
5
Department of Pediatrics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
6
Department of Microbiology and Immunology, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium
In August 2011, a single-centre cross-sectional study was carried out at the University Hospital of Kisangani (UHK), capital of the Oriental Province in the DRC. At the time of study, the hospital did not have an infection control policy regarding
Eur J Clin Microbiol Infect Dis
MRSA. The study protocol was approved by the Provincial Health Officer and the Director’s Board of the UHK. Medical students (MS) and HCW were invited to participate voluntarily during lectures, personal and/or professional contacts; they provided oral consent. Demographic data like age, gender and professional profile (healthcare professional versus medical student) were recorded and analysed anonymously. Cotton-tipped swabs were inserted into both anterior nares, immediately transported to the laboratory and inoculated onto Mannitol Salt Agar plates (Oxoid, Basingstoke, UK). The maximum time between sampling and culture did not exceed 4 h. Plates were incubated at 35 °C and examined after 24 and 48 h. Isolates were identified as S. aureus by mannitol fermentation and by positive reactions for DNase (Oxoid, Basingstoke, UK), catalase and coagulase tube testing (BD BBL™, Franklin Lakes, NJ, USA). Isolates were stored in Tryptone Soya Agar (Oxoid, Basingstoke, UK) and shipped to the Institute of Tropical Medicine in Belgium, where susceptibility testing was performed by the disc diffusion method (Rosco Diagnostica, Taastrup, Denmark), according to Clinical and Laboratory Standards Institute (CLSI) guidelines [7]. S. aureus ATCC® 25923 and ATCC® 43300 were used as quality control strains. At the Belgian National Reference Centre for S. aureus, isolates were confirmed as methicillin-susceptible S. aureus (MSSA) or MRSA by a 16S rRNA–nuc–mecA triplex polymerase chain reaction (PCR) and genotyped by spa typing, followed by spa-CC clustering, as described previously [8]. Panton–Valentine leucocidin (PVL)- and toxic shock syndrome toxin-1 (TSST-1)-encoding genes were determined for all isolates [8]. Multilocus sequence typing (MLST) was performed for every spa type detected among PVL-positive or TSST-1-positive isolates (n=11); SCCmec typing was done for all MRSA by ccr and mec complex determination [8]. All isolates assigned to ST8 were screened by PCR for the arginine deaminase gene arcA, which is integrated into the arginine catabolic mobile element (ACME) typically present in the MRSA USA300 genome [9]. Proportions of categorical variables were tested using the Chi-square test or, in the case of small sample sizes, a twotailed Fisher’s exact test. Differences in mean were assessed for significance by the Student’s t-test. Multivariable logistic regression was used to compare carrier rates. A p-value
ARTICLE
Staphylococcus aureus nasal carriage among healthcare workers in Kisangani, the Democratic Republic of the Congo H. De Boeck 1 & S. Vandendriessche 2 & M. Hallin 2,3 & B. Batoko 4 & J.-P. Alworonga 4 & B. Mapendo 4 & C. Van Geet 5 & N. Dauly 4 & O. Denis 2 & J. Jacobs 1,6
Received: 25 February 2015 / Accepted: 8 April 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Methicillin-resistant Staphylococcus aureus (MRSA) is a global health concern, but there are few data from Central Africa. The objective of our study was to characterise S. aureus colonisation isolates from healthcareexposed professionals in the Democratic Republic of the Congo (DRC). Healthcare workers and medical students (n=380) in Kisangani, DRC were screened for S. aureus nasal carriage in a single-centre cross-sectional study in the University Hospital of Kisangani. The isolates were identified and characterised using phenotypic and genotypic methods. The nasal carriage rate of S. aureus was 16.6 % and 10 out of 63 isolates (15.9 %) were MRSA. We found 28 different spa types. Most MRSA isolates belonged to ST8-spa t1476-SCCmec V. The majority of MRSA were
HDB and SV equally contributed to the present study and share first authorship. * H. De Boeck [email protected]
multidrug-resistant to non-beta-lactam antibiotics. Overall, 28.5 % of S. aureus carried Panton–Valentine leucocidin (PVL)-encoding genes (all methicillin-sensitive) and 17.5 % carried toxic shock syndrome toxin-1 (TSST-1)encoding genes. The finding of MRSA carriage among healthcare workers in a setting with limited access to diagnostic microbiology and appropriate therapy calls for improved education on infection control practices and supports the introduction of surveillance programmes.
Introduction Staphylococcus aureus is amongst the most frequent organisms affecting man. In many African countries, methicillinresistant S. aureus (MRSA) appear to be on the rise, but studies are scarce for sub-Saharan Africa (SSA), particularly Central Africa [1, 2]. The anterior nares are the primary colonisation site of S. aureus and S. aureus carriage is a known risk factor for S. aureus infection [3, 4]. The strain causing infection is usually also the nasal carriage strain [5]. In this regard, MRSA carriage is of particular relevance among healthcare workers (HCW), who may play a causal role in MRSA crosstransmission to patients [6]. The present study aimed to characterise S. aureus colonisation isolates from healthcareexposed professionals in the Democratic Republic of the Congo (DRC).
1
Department of Clinical Sciences, Institute of Tropical Medicine (ITM), Nationalestraat 155, 2000 Antwerp, Belgium
2
Centre National de Référence MRSA Staphylocoques, Microbiology, Hôpital Erasme—Université Livre de Bruxelles, Lennikse Baan 808, 1070 Anderlecht, Belgium
3
Centre de Diagnostic Moléculaire iris-Lab, Hôpital SaintPierre—Université Libre de Bruxelles, Rue Haute 322, 1000 Brussels, Belgium
4
Department of Pediatrics, University Hospital Kisangani, Kisangani, Democratic Republic of the Congo
Materials and methods
5
Department of Pediatrics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
6
Department of Microbiology and Immunology, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium
In August 2011, a single-centre cross-sectional study was carried out at the University Hospital of Kisangani (UHK), capital of the Oriental Province in the DRC. At the time of study, the hospital did not have an infection control policy regarding
Eur J Clin Microbiol Infect Dis
MRSA. The study protocol was approved by the Provincial Health Officer and the Director’s Board of the UHK. Medical students (MS) and HCW were invited to participate voluntarily during lectures, personal and/or professional contacts; they provided oral consent. Demographic data like age, gender and professional profile (healthcare professional versus medical student) were recorded and analysed anonymously. Cotton-tipped swabs were inserted into both anterior nares, immediately transported to the laboratory and inoculated onto Mannitol Salt Agar plates (Oxoid, Basingstoke, UK). The maximum time between sampling and culture did not exceed 4 h. Plates were incubated at 35 °C and examined after 24 and 48 h. Isolates were identified as S. aureus by mannitol fermentation and by positive reactions for DNase (Oxoid, Basingstoke, UK), catalase and coagulase tube testing (BD BBL™, Franklin Lakes, NJ, USA). Isolates were stored in Tryptone Soya Agar (Oxoid, Basingstoke, UK) and shipped to the Institute of Tropical Medicine in Belgium, where susceptibility testing was performed by the disc diffusion method (Rosco Diagnostica, Taastrup, Denmark), according to Clinical and Laboratory Standards Institute (CLSI) guidelines [7]. S. aureus ATCC® 25923 and ATCC® 43300 were used as quality control strains. At the Belgian National Reference Centre for S. aureus, isolates were confirmed as methicillin-susceptible S. aureus (MSSA) or MRSA by a 16S rRNA–nuc–mecA triplex polymerase chain reaction (PCR) and genotyped by spa typing, followed by spa-CC clustering, as described previously [8]. Panton–Valentine leucocidin (PVL)- and toxic shock syndrome toxin-1 (TSST-1)-encoding genes were determined for all isolates [8]. Multilocus sequence typing (MLST) was performed for every spa type detected among PVL-positive or TSST-1-positive isolates (n=11); SCCmec typing was done for all MRSA by ccr and mec complex determination [8]. All isolates assigned to ST8 were screened by PCR for the arginine deaminase gene arcA, which is integrated into the arginine catabolic mobile element (ACME) typically present in the MRSA USA300 genome [9]. Proportions of categorical variables were tested using the Chi-square test or, in the case of small sample sizes, a twotailed Fisher’s exact test. Differences in mean were assessed for significance by the Student’s t-test. Multivariable logistic regression was used to compare carrier rates. A p-value
