Blood culture surveillance in a secondary care hospital in Benin: epidemiology of bloodstream infection pathogens and antimicrobial resistance.

BACKGROUND: Although global surveillance of antimicrobial resistance (AMR) is considered key in the containment of AMR, data from low- and middle-income countries, especially from sub-Saharan Africa, are scarce. This study describes epidemiology of bloodstream infections and antimicrobial resistance rates in a secondary care hospital in Benin. METHODS: Blood cultures were sampled, according to predefined indications, in BacT/ALERT FA Plus and PF Plus (bioMérieux, Marcy-l'Etoile, France) blood culture bottles (BCB) in a district hospital (Boko hospital) and to a lesser extent in the University hospital of Parakou. These BCB were incubated for 7 days in a standard incubator and twice daily inspected for visual signs of growth. Isolates retrieved from the BCB were processed locally and later shipped to Belgium for reference identification [matrix-assisted laser desorption/ionization time-of-flight spectrometry (MALDI-TOF)] and antibiotic susceptibility testing (disk diffusion and E-tests). RESULTS: From October 2017 to February 2020, 3353 BCB were sampled, corresponding to 3140 blood cultures (212 cultures consisting of  > 1 BCB) and 3082 suspected bloodstream infection (BSI) episodes. Most of these cultures (n = 2471; 78.7%) were sampled in children < 15 years of age. Pathogens were recovered from 383 (12.4%) cultures, corresponding to 381 confirmed BSI. 340 of these pathogens were available and confirmed by reference identification. The most common pathogens were Klebsiella pneumoniae (n = 53; 15.6%), Salmonella Typhi (n = 52; 15.3%) and Staphylococcus aureus (n = 46; 13.5%). AMR rates were high among Enterobacterales, with resistance to third-generation cephalosporins in 77.6% of K. pneumoniae isolates (n = 58), 12.8% of Escherichia coli isolates (n = 49) and 70.5% of Enterobacter cloacae isolates (n = 44). Carbapenemase production was detected in 2 Escherichia coli and 2 Enterobacter cloacae isolates, all of which were of the New Delhi metallo-beta lactamase type. Methicillin resistance was present in 22.4% of S. aureus isolates (n = 49). CONCLUSION: Blood cultures were successfully implemented in a district hospital in Benin, especially among the pediatric patient population. Unexpectedly high rates of AMR among Gram-negative bacteria against commonly used antibiotics were found, demonstrating the clinical and scientific importance of clinical bacteriology laboratories at this level of care.

Pathogenic features of clinically significant coagulase-negative staphylococci in hospital and community infections in Benin.

In West Africa, very little consideration has been given to coagulase negative Staphylococci (CNS). Herein, we describe the features contributing to the pathogenicity of 99 clinically-significant independent CNS isolates associated with infections encountered at the National Teaching Hospital Center of Cotonou (Benin). The pathogenic potentials of nosocomial strains were compared with community strains. S. haemolyticus (44%), S. epidermidis (22%) and S. hominis (7%) were the most frequently isolated while bacteremia (66.7%) and urinary tract infections (24.2%) were the most commonly encountered infections. Most strains were resistant to multiple antibiotics, including penicillin (92%), fosfomycin (81%), methicillin (74%) and trimethoprim-sulfamethoxazole (72%). The most frequently isolated species were also the most frequently resistant to methicillin: S. hominis (100%), S. haemolyticus (93%) and S. epidermidis (67%). Screening of toxic functions or toxin presence revealed hemolytic potential in 25% of strains in over 50% of human erythrocytes in 1h. Twenty-six percent of strains exhibited protease activity with low (5%), moderate (10%) and high activity (11%), while 25% of strains displayed esterase activity. Three percent of strain supernatants were able to lyse 100% of human polymorphonuclear cells after 30min. Polymerase chain reaction and latex agglutination methods revealed staphylococcal enterotoxin C gene expression in 9% of S. epidermidis. A majority of hospital-associated CNS strains (68%) had at least one important virulence feature, compared with only 32% for community-acquired strains. The present investigation confirms that these microorganisms can be virulent, at least in some individual cases, possibly through genetic transfer from S. aureus.

First Insight into a Nationwide Genotypic Diversity of Mycobacterium tuberculosis among Previously Treated Pulmonary Tuberculosis Cases in Benin, West Africa.

BACKGROUND: Molecular studies on tuberculosis (TB) are rare in low-resource countries like Benin, where data on molecular study on previously treated TB cases is unavailable. MATERIALS AND METHODS: From January to December 2014, all smear- and culture-positive previously treated pulmonary TB patients from all TB clinics were systematically recruited. Drug susceptibility testing and spoligotyping were performed on all isolates. RESULTS: Of the 100 patients recruited, 71 (71.0%) were relapse cases and 24 (24.0%) were failure cases, while 5 (5.0%) were default cases. Resistance rate to any first-line drug was 40.0%, while 12.0% of strains were multidrug-resistant (MDR) and no strain was extensively drug-resistant (XDR). A total of 40 distinct spoligotypes were found to be corresponding to a genotypic diversity of 40.0%. ST61 was the most predominant spoligotype with prevalence of 33.0%. In all, 31 single spoligotypes and nine clusters were observed with 2 to 33 strains per cluster giving a clustering rate of 69.0%. Euro-American (Lineage 4) was the most prevalent lineage (74.0%) and Lineage 2 was associated with resistance to streptomycin. CONCLUSION: This first insight into genetic diversity of previously treated pulmonary TB patients in Benin showed a relatively high genetic diversity of Mycobacterium tuberculosis.

Rapid detection of extended-spectrum-ß-lactamase-producing Enterobacteriaceae in blood cultures using the ESBL NDP test in Cotonou, Benin.

PURPOSE: Rapid and inexpensive tests for detecting extended-spectrum-ß-lactamase (ESBL)-producing Enterobacteriaceae are needed, particularly in low-resource countries where infections with these bacteria constitute a major public health issue. The recently described ESBL NDP test performed well in developed countries. This study was designed to assess performance, cost and feasibility of this test in positive blood cultures, in Cotonou, Benin (West Africa). METHODOLOGY: The test was performed on 175 positive Bactec broth blood cultures containing Enterobacteriaceae, and blindly compared with the double-disc synergy test (DDST) for the phenotypic detection of ESBL producers. RESULTS: There was a complete agreement between the ESBL NDP test and the DDST. On average, the time to give results was 37 min for a sample and the cost was US$ 7.3. CONCLUSION: The ESBL NDP test is rapid, relatively affordable and performed well in our setting.