Surgical-site infection is the most frequent health care-associated infection in the developing world, with a strikingly higher prevalence than in developed countries We studied the prevalence of resistance to antibiotics in Enterobacteriaceae isolates from surgical-site infections collected in three major tertiary care centres in Bangui, Central African Republic. We also studied the genetic basis for antibiotic resistance and the genetic background of third-generation cephalosporin-resistant (3GC-R) Enterobacteriaceae. Between April 2011 and April 2012, 195 patients with nosocomial surgical-site infections were consecutively recruited into the study at five surgical departments in three major tertiary care centres. Of the 165 bacterial isolates collected, most were Enterobacteriaceae (102/165, 61.8%). Of these, 65/102 (63.7%) were 3GC-R, which were characterized for resistance gene determinants and genetic background. The bla CTX-M-15 and aac(6′)-Ib-cr genes were detected in all strains, usually associated with qnr genes (98.5%). Escherichia coli, the most commonly recovered species (33/65, 50.8%), occurred in six different sequence types, including the pandemic B2-O25b-ST131 group (12/33, 36.4%). Resistance transfer was studied in one representative strain of the resistance gene content in each repetitive extragenic palindromic and enterobacterial repetitive intergenic consensus sequence-PCR banding pattern. Plasmids were characterized by PCR-based replicon typing and sub-typing schemes. In most isolates (18/27, 66.7%), bla CTX-M-15 genes were found in incompatibility groups F/F31:A4:B1 and F/F36:A4:B1 conjugative plasmids. Horizontal transfer of both plasmids is probably an important mechanism for the spread of bla CTX-M-15 among Enterobacteriaceae species and hospitals. The presence of sets of antibiotic resistance genes in these two plasmids indicates their capacity for gene rearrangement and their evolution into new variants. Diverse modes are involved in transmission of resistance, plasmid dissemination probably playing a major role.

Neonatal infection constitutes one of Senegal’s most important public health problems, with a mortality rate of 41 deaths per 1,000 live births. Between January 2007 and March 2008, 242 neonates with suspected infection were recruited at three neonatal intensive care units in three major tertiary care centers in Dakar, the capital of Senegal. Neonatal infections were confirmed by positive bacterial blood or cerebrospinal fluid culture. The microbiological pattern of neonatal infections and the antibiotic susceptibility of the isolates were characterized. In addition, the genetic basis for antibiotic resistance and the genetic background of third-generation cephalosporin-resistant (3GC-R) Enterobacteriaceae were studied. A bacteriological infection was confirmed in 36.4 % (88/242) of neonates: 22.7 % (30/132) during the early-onset and 52.7 % (58/110) during the late-onset periods (p > 0.20). Group B streptococci accounted for 6.8 % of the 88 collected bacterial isolates, while most of them were Enterobacteriaceae (n = 69, 78.4 %). Of these, 55/69 (79.7 %) were 3GC-R. The blaCTX-M-15 allele, the blaSHV and the blaTEM were highly prevalent (63.5, 65.4 and 53.8 %, respectively), usually associated with qnr genes (65.4 %). Clonally related strains of 3GC-R Klebsiella pneumoniae and 3GC-R Enterobacter cloacae, the two most commonly recovered 3GC-R Enterobacteriaceae (48/55), were detected at the three hospitals, underlining the role of cross-transmission in their spread. The overall case fatality rate was 18.6 %. Measures should be taken to prevent nosocomial infections and the selection of resistant bacteria.

From May 2004 to October 2006, a prospective study was carried out in Dakar, Senegal, to update information about the antimicrobial susceptibility of Shigella spp. isolated from stool specimens. Among the 165 non-duplicate strains collected, 81 (49%) were identified as Shigella flexneri, 75 (45%) as Shigella sonnei, 5 (3%) as Shigella boydii, and 4 (2%) as Shigella dysenteriae. Disk diffusion testing revealed that the majority of isolates were resistant to sulphonamides, trimethoprim-sulfamethoxazole, streptomycin, and tetracycline (respective overall resistance rates: 90, 90, 96, and 94%). More than half of the S. flexneri isolates were resistant to amoxicillin, amoxicillin-clavulanic acid, and chloramphenicol (respective resistance rates: 59, 58, and 52%), and almost all of the S. sonnei isolates were susceptible to these antimicrobials (respective resistance rates: 4, 1, and 4%). Only one isolate (belonging to the species S. sonnei) was resistant to nalidixic acid and displayed reduced susceptibility to ciprofloxacin.

Leptospirosis is a neglected zoonotic bacterial disease caused by pathogenic Leptospira spp. Only limited studies have been conducted on the presence of Leptospira spp. in rats in Antananarivo, the capital city of Madagascar. We assessed Leptospira prevalence in small mammals in urban areas of Antananarivo where sanitation is inadequate and there is risk of flooding during the rainy season. We captured rodents and shrews at two sites and examined kidney samples from 114 animals using culture and a real-time polymerase chain reaction (PCR) assay specific to pathogenic Leptospira spp. We identified 23 positive samples containing Leptospira interrogans and Leptospira borgpetersenii, with a high prevalence in Rattus norvegicus (44.9%). Our results indicate that small mammals, in particular R. norvegicus, present a major public health risk for acquiring leptospirosis in Antananarivo.

Melioidosis, caused by the bacterium Burkholderia pseudomallei, is an infectious disease of humans or animals, and the specific environmental conditions that are present in western Indian Ocean islands are particularly suitable for the establishment/survival of B. pseudomallei. Indeed, an increasing number of new cases have been reported in this region (Madagascar, Mauritius, Réunion (France), and Seychelles, except Comoros and Mayotte (France)), and are described in this review. Our review clearly points out that further studies are needed in order to investigate the real incidence and burden of melioidosis in the western Indian Ocean and especially Madagascar, since it is likely to be higher than currently reported. Thus, research and surveillance priorities were recommended (i) to improve awareness of melioidosis in the population and among clinicians; (ii) to improve diagnostics, in order to provide rapid and effective treatment; (iii) to implement a surveillance and reporting system in the western Indian Ocean; and (iv) to investigate the presence of B. pseudomallei in environmental samples, since we have demonstrated its presence in soil samples originating from the yard of a Madagascan case.