Antibiotic susceptibility/resistant gene profiles of Group B streptococci isolates from pregnant women in a tertiary institution in Nigeria

Background: Penicillin is recommended as the first-line agent for intrapartum antibiotic prophylaxis (IAP). Although Group B Streptococcus (GBS) strains are generally susceptible to penicillin with only occasional resistance, they show varying resistance to erythromycin, clindamycin, and tetracycline. Therefore, knowledge of the resistance profile of GBS in the local environment will be useful for administration of appropriate intrapartum antibiotics prophylaxis. Methodology: Rectovaginal swabs collected from pregnant women were cultured for GBS using conventional media. Kirby-Bauer disc diffusion method was performed according to the Clinical and Laboratory Standards Institute guidelines on GBS isolates to determine the antibiotic susceptibility patterns of the isolates. Inducible clindamycin resistance was detected by using the D-zone test. Resistance determinants genes were discerned with conventional polymerase chain reaction. Results: Carriage rates of GBS among pregnant women studied were 19.7%. GBS colonizing the pregnant mothers were uniformly susceptible (100%) to penicillin, vancomycin, and ceftriaxone. Only three (6.5%) of the isolates showed inducible clindamycin resistance. ermA gene was present in all three GBS isolates with inducible macrolide-lincosamide-streptogramin resistance. ermB was absent in all the strains tested. mefA/E gene was carried by two of the macrolide-clindamycin resistance isolates. tetM gene was carried by all isolates with tetracycline resistance phenotypes. Conclusion: In this study, all GBS isolates were susceptible to penicillin G, the recommended antibiotic for IAP. The presence of resistance to erythromycin and inducible resistance to clindamycin excludes the use of these agents as alternatives in cases of penicillin allergy. In this case, vancomycin is the drug of choice as recommended in the updated Centers for Disease Control guideline

Feasibility and cost analysis of programmatic implementation of Microscopic-Observation Drug Susceptibility (MODS) assay in Nigeria

Objectives: Detection of Multi-drug resistant tuberculosis in Nigeria still remains a challenge. We evaluated the feasibility of programmatic implementation of the Microscopic-Observation Drug Susceptibility (MODS) assay, a rapid culture and drug susceptibility testing technique for drug susceptibility testing in a low resource setting.Method: In a novel laboratory setting in Nigeria, we obtained data from the market on the cost of materials necessary for MODS assay. Three routinely collected sputum specimens from 160 tuberculosis suspects were evaluated by smear microscopy while only the early morning specimen was used for MODS culture.Results: MODS assay detected M. tuberculosis in 97.7% (42/43) of smear positive and 6.0% (7/117) of smear negative TB suspects. There was a statistically significant advantage of a single MODS culture over 3 smear microscopies (P=0.019). The modal time from culture of specimen to detection of M. tuberculosis and availability of drug susceptibility result for MODS was 7days with a mean of 8.4 days (Range= 5-13 days). Culture and susceptibility result was available in 18.4% (9/49) of patients within 5days of culture. Turnaround time for smear microscopy in the centers was 3 days. Cost of processing one specimen by MODS assay in the study was USD2.65. Multi-Drug resistant tuberculosis (MDR-TB) was detected in 4.1% (2/49) while Isoniazid mono-resistance was detected in 2.0% (1/49) of the culture positive cases. All the drug resistant isolates were from re-treatment cases with a statistically significant association (P=0.005).Conclusion: The MODS technique is simple, and its implementation in this novel setting was feasible. MODS can be scaled up to meet the demand for MDR-TB confirmation in XpertMTB/Rif deployed sites in Nigeria.Keywords: Tuberculosis, MDR-TB, Mycobacterium tuberculosi

Candidaemia in a tertiary hospital in Nigeria

Background: Candidaemia is a widely-studied and reviewed topic in the developed world; however, there is a dearth of information on nosocomial candidaemia in Nigeria, despite the increasing use of more invasive therapeutic modalities, immunosuppressive agents and increasing incidence of immunosuppression as a result of malignancies and HIV. Objectives: To determine the hospital-based frequency of candidaemia in a tertiary hospital in Ibadan, Nigeria. Method: This was a prospective descriptive study which included 230 immunosuppressed patients. All isolates were identified to the species level using both conventional and automated methods. Thereafter, all Candida species isolated were tested for antifungal susceptibility using the broth microdilution method. Results: Candidaemia occurred in 12 (5.21%) of the 230 study patients, with C. tropicalis accounting for 50% of the infections. Four patients (33.3%) presented with C. parapsilosis, one (8.3%) with C. albicans and one (8.3%) with a mixed infection of C. albicans and C. tropicalis. All 12 isolates were sensitive to fluconazole (minimal inhibitory concentration < 8 mg/mL). Univariate analysis revealed that old age, multiple surgeries and long-term hospitalisation were significant contributing factors for the occurrence of candidaemia. Eleven (91.7%) of the 12 patients with candidaemia had Candida colonisation of other sterile sites including the bladder, peritoneum and trachea. Furthermore, bivariate analysis revealed that mucositis (p = 0.019) and diarrhoea (p = 0.017) were significantly associated with an increased risk of candidaemia. The crude mortality rate of candidaemia was 91.7%. Conclusion: This study highlights the significance of nosocomial candidaemia and the need for proactive laboratory investigation and clinical management of this life-threatening disease

Car windshield fragments as cheap alternative glass beads for homogenization of Mycobacterium tuberculosis cultures in a resource-limited setting

Tuberculosis is a global health problem which has been compounded by the emergence and rapid spread of drug resistant strains. Phenotypic drug susceptibility testing of Mycobacterium tuberculosis usually requires homogenization of cultures using 3–5 mm glass beads. In resource limited settings, these important material may either not be readily available in the country as in our case requiring that one orders them from abroad or they may be too expensive. In both situations, this would impact on the usually lean budget. In our centre were we recently introduced tuberculosis culture and drug susceptibility testing using the Microscopic Observation Drug Susceptibility (MODS) technique, we successfully used glass fragments from a broken car windshield obtained from a mechanic workshop to homogenize solid cultures to prepare positive controls. All cultures homogenized with these local beads gave consistent MODS results. The challenge of the limited availability of resources for research in resource limited settings can be met by adapting available materials to achieve results

Fluconazole susceptibility and ERG11 gene expression in vaginal candida species isolated from Lagos Nigeria

Fluconazole resistance is an important type of resistance in Candida because in most countries, fluconazole is the drug of choice for vulvovaginal candidiasis. Candida species resist fluconazole by various mechanisms but there is paucity of data on these in our environment. Such mechanisms include among others, over-expression of the ERG11 gene, which codes for synthesis of the target enzymes in the fungus. The aim of this study was to screen Candida spp. resistant to fluconazole for the expression of ERG11 gene. Fluconazole susceptibility test was performed on 28 clinical strains of Candida species previously obtained from students of a School of Nursing in Lagos, Nigeria. They were identified by API Candida, CHROMagar candida and germ tube test. Using 25 mcg discs, fluconazole susceptibility was determined by the disc diffusion method and results were interpreted in accordance with the Clinical Laboratory Standard Institute (CLSI) criteria; sensitive (S), resistant (R) and susceptible dose dependent (SDD). The R and SDD isolates were subsequently evaluated for the presence of ERG11 gene. Of the 28 clinical isolates, 14 were identified as C. albicans and six as C. tropicalis. The remaining isolates were identified as C. glabrata (2), C. famata (2) C. kefyr (2) one each of C. parapsilosis and C. guilliermondii respectively. In this study, 18 were susceptible (S) to fluconazole, eight were SDD and two were resistant to the antifungal agent. Out of the 14 C. albicans isolates, 12 were susceptible, one showed high level resistance and similar number showed susceptible dose dependence. ERG11 was detected in three susceptible dose dependent Candida species. This analysis demonstrates that susceptible dose dependence should not be overlooked as it may be associated with the presence of ERG11 gene and resistance to fluconazole. There is a need to consider routine antifungal susceptibility testing for Candida species causing vulvovaginitis.</p

The global point prevalence survey of antimicrobial consumption and resistance (Global-PPS): First results of antimicrobial prescribing in a children hospital in Nigeria

Background: Antimicrobial stewardship is vital for our hospital practice but it requires a knowledge of antibiotic prescribing practices, which is currently lacking. This survey aimed to assess the antimicrobial prescribing practices in our hospital. Method: To obtain baseline information on antimicrobial prescribing practices, a uniform and standardized method for surveillance of antibiotic use in hospitals was employed. A point prevalence survey (PPS) was conducted in all the wards of the Massey Street Children’s hospital in June 2019. The PPS included all i n p a t i e n t s r e c e i v i n g a n antimicrobial on the day of survey. Data collected included age, gender, antimicrobial agents, microbiological data, and compliance to guidelines, documentation of reasons and stop/ review date of prescription. The denominator was the number of eligible patients. A web-based application developed by the University of Antwerp was used for data-entry, validation and reporting. Results: Sixty-seven children were eligible, of which 62 (92%) CC –BY 4.0 received 128 antimicrobials. Fifty- seven (85%) were on multiple antimicrobial therapies, and route of administration was parenteral in 86%. All prescriptions were empiric. Reasons for prescribing were documented in 121(94.5%) therapies in case notes; Stop/review dates were not documented in 126(98.4%). The most frequently prescribed antibiotics we r e c e f u r o x i m e ( 1 8 % ) , Ampicillin-sulbactam (15%) and gentamicin (12%). Antibiotic guidelines were not available. Most common diagnoses were sepsis (42%), pneumonia (15%) and malaria (9%). Conclusion: This survey revealed v e r y h i g h a n t i m i c r o b i a l prescribing rates in the hospital and the need to assess it appropriateness. We disclosed areas to improve antibiotic prescribing: antibiotic prescribing according to guidelines and low reporting of a stop/review date. There is a need to create awareness for evidence based antibiotic guidelines

High Genetic Diversity of Carbapenem-Resistant Acinetobacter baumannii Isolates Recovered in Nigerian Hospitals in 2016 to 2020

ABSTRACT Acinetobacter baumannii causes difficult-to-treat infections mostly among immunocompromised patients. Clinically relevant A. baumannii lineages and their carbapenem resistance mechanisms are sparsely described in Nigeria. This study aimed to characterize the diversity and genetic mechanisms of carbapenem resistance among A. baumannii strains isolated from hospitals in southwestern Nigeria. We sequenced the genomes of all A. baumannii isolates submitted to Nigeria’s antimicrobial resistance surveillance reference laboratory between 2016 and 2020 on an Illumina platform and performed in silico genomic characterization. Selected strains were sequenced using the Oxford Nanopore technology to characterize the genetic context of carbapenem resistance genes. The 86 A. baumannii isolates were phylogenetically diverse and belonged to 35 distinct Oxford sequence types (oxfSTs), 16 of which were novel, and 28 Institut Pasteur STs (pasSTs). Thirty-eight (44.2%) isolates belonged to none of the known international clones (ICs). Over 50% of the isolates were phenotypically resistant to 10 of 12 tested antimicrobials. The majority (n = 54) of the isolates were carbapenem resistant, particularly the IC7 (pasST25; 100%) and IC9 (pasST85; >91.7%) strains. blaOXA-23 (34.9%) and blaNDM-1 (27.9%) were the most common carbapenem resistance genes detected. All blaOXA-23 genes were carried on Tn2006 or Tn2006-like transposons. Our findings suggest that a 10-kb Tn125 composite transposon is the primary means of blaNDM-1 dissemination. Our findings highlight an increase in blaNDM-1 prevalence and the widespread transposon-facilitated dissemination of carbapenemase genes in diverse A. baumannii lineages in southwestern Nigeria. We make the case for improving surveillance of these pathogens in Nigeria and other understudied settings. IMPORTANCE Acinetobacter baumannii bacteria are increasingly clinically relevant due to their propensity to harbor genes conferring resistance to multiple antimicrobials, as well as their ability to persist and disseminate in hospital environments and cause difficult-to-treat nosocomial infections. Little is known about the molecular epidemiology and antimicrobial resistance profiles of these organisms in Nigeria, largely due to limited capacity for their isolation, identification, and antimicrobial susceptibility testing. Our study characterized the diversity and antimicrobial resistance profiles of clinical A. baumannii in southwestern Nigeria using whole-genome sequencing. We also identified the key genetic elements facilitating the dissemination of carbapenem resistance genes within this species. This study provides key insights into the clinical burden and population dynamics of A. baumannii in hospitals in Nigeria and highlights the importance of routine whole-genome sequencing-based surveillance of this and other previously understudied pathogens in Nigeria and other similar settings