Secondary bacterial isolates from previously untreated Buruli ulcer lesions and their antibiotic susceptibility patterns in Southern Nigeria

Abstract

Introduction: Mycolactones, secreted by Mycobacterium ulcerans, were previously believed to prevent super infection in Buruli ulcer lesions. However, little is known about secondary bacterial infections in these lesions. This study evaluated contaminating bacterial fl ora and their antibiotic susceptibility patterns in cases of previously untreated Buruli ulcer disease from three states in Southern Nigeria. Methods: A prospective analysis was conducted between January and June of 2015 using wound swabs from eligible patients with Buruli ulcer disease, confi rmed by quantitative-polymerase chain reaction, with active ulcers. Microbiological analyses including isolation of bacteria, species identifi cation of isolates, and drug susceptibility tests were performed. Results: Of 51 patients, 27 (52.9%) were female. One or more bacterial species of clinical importance was isolated from each patient. A total of 17 different microbial species were isolated; 76.4% were Gram-negative and 23.6% were Gram-positive isolates. The most common bacterial species detected was Staphylococcus aureus (24%), followed by Aeromonas hydrophila (13%), Pseudomonas aeruginosa (13%), and Klebsiella pneumoniae (11%). Drug susceptibility tests showed a particularly high frequency of resistance to commonly used antimicrobials in Nigeria for Staphylococcus aureus. Conclusions: Super bacterial infections occur in Buruli ulcer lesions in Nigeria, and these infections are associated with high rates of resistance to commonly used antibiotics in the country.

Report of a series of 82 cases of Buruli ulcer from Nigeria treated in Benin, from 2006 to 2016

“…In this study about Nigeria cases, less than half of the patients (41.7%) were aged < 15 years [ 39 ]. This result is similar to that observed by other authors in Nigeria in 2016 [ 40 – 42 ]. It cannot, however, be interpreted as BU mainly affecting older people in Nigeria since the opposite result was observed from the previous study in Pobè among the PCR-confirmed BU cases from Nigeria [ 35 ].…”

Secondary Infection of Buruli Ulcer Lesions

“…Extensive work on the microbial flora of BU wounds has been done by research groups in Ghana [10], Benin [14] and Nigeria [13]. Yeboah-Manu and Barogui studied the microbial flora of BU patients before, during and post antibiotic treatment while the study by Anyim included pre-treatment patients only.…”

“…Secondary infection in BU disease is not well characterized and recognized because it is assumed to be infrequent [11]. Thus, its occurrence has been documented only by few studies [10,[12][13][14][15][16]. Previously, it was speculated that mycolactone secreted by M. ulcerans during active disease may sterilize BU wounds and prevent secondary infection by other bacteria, since a number of macrolides have broad spectrum activity against many bacterial species including streptococci, pneumococci, staphylococci, enterococci, mycoplasma, mycobacteria, rickettsia, and chlamydia [17].…”

Challenges associated with the treatment of Buruli ulcer

“…). Studies documenting the occurrence of secondary infection with the isolation of infecting pathogens and the growth of microbial pathogens in the presence of mycolactone have given evidence to support the occurrence of secondary infection in BU and proven that mycolactone does not prevent its occurrence. Secondary infection in BU should be suspected when a wound becomes painful or develops cellulitis .…”

“…Secondary infection in BU should be suspected when a wound becomes painful or develops cellulitis . Studies identifying the microbial flora of secondarily infected BU lesions isolated a diverse and broad range of infecting bacterial species including Staphylococcus aureus , Pseudomonas aeruginosa , Proteus mirabilis , Coagulase negative Staphylococcus, Chryseomonas luteola , Enterobacter cloacae , Klebsiella pneumonia , Escherichia coli , Streptococcus dysgalactia , Providencia stuartii , Staphylococcus haemolyticus , Group A streptococci, Group B or C streptococci, Morganella morganii , Streptococcus agalactia , Staphylococcus warneri , Proteus vulgaris , Pseudomonas pseudomallei , and Burkholderia cepacia. S. aureus and P. aeruginosa however dominated among the isolated species.…”