Kennedy Kwasi Addo

Molecular Epidemiology and Antimicrobial Susceptibility of Clinical Staphylococcus aureus from Healthcare Institutions in Ghana

The objective of this study was to determine the antimicrobial susceptibility patterns and clonal diversity of clinical Staphylococcus aureus isolates from Ghana. A total of 308 S. aureus isolates from six healthcare institutions located across Northern, Central and Southern Ghana were characterized by antibiotyping, spa typing and PCR detection of Panton Valentine leukocin (PVL) genes. Methicillin-resistant S. aureus (MRSA) were confirmed by PCR detection of mecA gene and further characterized by SCCmec and multi-locus sequence typing (MLST). The prevalence of antimicrobial resistance was below 5% for all agents tested except for penicillin (97%), tetracycline (42%) and erythromycin (6%). Ninety-one spa types were found, with t355 (ST152, 19%), t084 (ST15, 12%) and t314 (ST121, 6%) being the most frequent types. Based on established associations between spa and MLST types, isolates were assigned to 16 clonal complexes (CCs): CC152 (n = 78), CC15 (n = 57), CC121 (n = 39), CC8 (n = 36), CC5 (n = 33), CC1 (n = 29), CC45 (n = 9), CC88 (n = 8), CC30 (n = 4), CC9 (n = 3), CC25 (n = 2), CC97 (n = 2) CC20 (n = 2), CC707 (n = 2), CC7 (n = 3) and CC522 (n = 1). Most isolates (60%) were PVL-positive, especially those belonging to ST152, ST121, ST5, ST15, ST1, ST8, and ST88. Nine (3%) isolates were MRSA belonging to seven distinct clones: ST88-IV (n = 2), ST250-I (n = 2), ST8-IV (n = 1), ST72-V (n = 1), ST789-IV (n = 1), ST2021-V (n = 1), and ST239-III (n = 1). The study confirmed a high frequency of PVL-positive S. aureus in Africa, low prevalence of antimicrobial resistance and high diversity of MRSA lineages in Ghana compared to developed countries and other African countries. The detection of known pandemic MRSA clones in the absence of routine MRSA identification in most Ghanaian clinical microbiology laboratories calls for capacity building to strengthen surveillance and prevent spread of these clones.

Microbiological quality and antibiotic residues in informally marketed raw cow milk within the coastal savannah zone of Ghana

Objectives  To investigate the microbiological quality and the presence of antibiotic residues in raw cow milk and in some indigenous milk products produced and marketed by the informal sector in the coastal savannah zone of Ghana.

Insights into Nasal Carriage of Staphylococcus aureus in an Urban and a Rural Community in Ghana

The epidemiology of Staphylococcus aureus in the community in Ghana was never investigated prior to this study. The aims of the study were: i) to assess prevalence of nasal S. aureus carriage in Ghanaian people living in an urban and a rural area, and ii) to identify phenotypic and genotypic traits of strains isolated from the two communities. Nasal swabs were collected from healthy individuals living in an urban community situated in the suburb of the capital city, Accra (n = 353) and in a rural community situated in the Dangme-West district (n = 234). The overall prevalence of nasal carriage was 21% with a significantly higher prevalence in the urban (28%) than in the rural community (11%) (p<0.0001). The levels of antimicrobial resistance were generally low (<5%) except for penicillin (91%) and tetracycline (25%). The only two (0.3%) MRSA carriers were individuals living in the urban area and had been exposed to hospitals within the last 12 months prior to sampling. Resistance to tetracycline (p = 0.0009) and presence of Panton-Valentine leukocidin (PVL) gene (p = 0.02) were significantly higher among isolates from the rural community compared to isolates from the urban community. Eleven MLST clonal complexes (CC) were detected based on spa typing of the 124 S. aureus isolates from the two communities: CC8 (n = 36), CC152 (n = 21), CC45 (n = 21), CC15 (n = 18), CC121 (n = 6), CC97 (n = 6), CC30 (n = 5), CC5 (n = 5), CC508 (n = 4), CC9 (n = 1), and CC707 (n = 1). CC8 and CC45 were less frequent in the rural area than in the urban area (p = 0.02). These results reveal remarkable differences regarding carriage prevalence, tetracycline resistance, PVL content and clonal distribution of S. aureus in the two study populations. Future research may be required to establish whether such differences in nasal S. aureus carriage are linked to socio-economic differences between urban and rural communities in this African country.

Prevalence of nasal carriage and diversity of Staphylococcus aureus among inpatients and hospital staff at Korle Bu Teaching Hospital, Ghana

There is a paucity of data on Staphylococcus aureus epidemiology in Africa. Prevalence of nasal carriage and genetic diversity of S. aureus were determined among hospital staff (HS) and inpatients (IP) at the largest hospital in Ghana. In total, 632 nasal swabs were obtained from 452 IP and 180 HS in the Child Health Department (CHD) and Surgical Department (SD). S. aureus carriage prevalences were 13.9% in IP and 23.3% in HS. The chance of being a carrier was higher in HS (P=0.005) and IP staying ≤7 days in hospital (P=0.007). Resistance to penicillin (93%), tetracycline (28%) and fusidic acid (12%) was more common than for other agents (<5%). A higher chance of multidrug-resistant S. aureus carriage was observed among IP compared with HS (P=0.01). High genetic diversity was shown by spa typing, with 55 spa types found among 105 isolates; the predominant spa types were t355 (10%) and t084 (10%). MRSA was detected in six IP with an overall carriage prevalence of ca. 1.3%, but not in HS. All three MRSA isolates from SD belonged to ST88-SCCmec IV, and two of them displayed the same spa type and antibiograms; three MRSA isolates from CHD belonged to distinct lineages (ST88-SCCmec IV, ST8-SCCmec V and ST72-SCCmec V). Altogether, these data indicate a high diversity of S. aureus, low levels of MRSA carriage, and a higher chance of nasal carriage of multidrug-resistant S. aureus among IP compared with HS in this hospital.

Methicillin-resistant Staphylococcus aureus strains from Ghana include USA300

The objective of this study was to provide baseline information on circulating methicillin-resistant Staphylococcus aureus (MRSA) clones in Ghana. Thirty MRSA isolates collected between 2010 and 2013 from patients and healthy carriers were characterised by DNA microarray analysis, staphylococcal protein A (spa) typing, multilocus sequence typing (MLST) and minimum inhibitory concentration (MIC) determination to 21 antimicrobial agents. Phenotypic resistance was detected to tetracycline (67%), norfloxacin (40%), moxifloxacin (37%), erythromycin (37%), clindamycin (33%), gentamicin (30%), kanamycin (30%) and ceftaroline (20%), whereas no resistance was observed for glycopeptides, linezolid, daptomycin and tigecycline. DNA microarray analysis showed that tet(M) (43%), tet(K) (33%), aphA3 (23%), aacA-aphD (17%) and erm(C) (13%) were the most prevalent resistance genes. ST88-IV (WA MRSA-2) (n=8), ST8-IV (USA300) (n=5) containing arginine catabolic mobile element (ACME) and Panton-Valentine leukocidin (PVL), and ST247-I (North German/Iberian EMRSA) (n=4) were the most frequent clones detected. All MRSA contained sak and scn genes, one isolate (ST36-II) harboured the gene encoding the toxic shock syndrome toxin (TSST) and none contained exfoliative toxin genes. In conclusion, the relatively high levels of resistance to easily accessible non-β-lactam agents further complicate the treatment of MRSA infections in Ghana. The occurrence of USA300 and other epidemic multidrug-resistant MRSA clones in this African country is a matter of public health concern due to the lack of adequate infrastructures for MRSA surveillance and control in this geographical setting.

A tuberculin skin test survey among Ghanaian school children.

BackgroundGhana has not conducted a national tuberculin survey or tuberculosis prevalence survey since the establishment of the National Tuberculosis Control Programme. The primary objective of this study was therefore to determine the prevalence of tuberculin skin sensitivity in Ghanaian school children aged 6-10 years in 8 out of 10 regions of Ghana between 2004 and 2006.MethodsTuberculin survey was conducted in 179 primary schools from 21 districts in 8 regions. Schools were purposively selected so as to reflect the proportion of affluent private and free tuition public schools as well as the proportion of small and large schools.ResultsOf the 24,778 children registered for the survey, 23,600 (95.2%) were tested of which 21,861 (92.6%) were available for reading. The age distribution showed an increase in numbers of children towards older age: 11% of the children were 6 years and 25%, 10 years. Females were 52.5% and males 47.5%. The proportion of girls was higher in all age groups (range 51.4% to 54.0%, p < 0.001). BCG scar was visible in 89.3% of the children. The percentage of children with a BCG scar differed by district and by age. The percentage of children with a BCG scar decreased with increasing age in all districts, reflecting increasing BCG vaccination coverage in Ghana in the last ten years. The risk of tuberculosis infection was low in the northern savannah zones compared to the southern coastal zones. Using a cut-off of 15 mm, the prevalence of infection ranged from 0.0% to 5.4% and the Annual Risks of Tuberculosis Infection 0.0% to 0.6%. There was an increase in the proportion of infected children after the age of 7 years. Children attending low and middle-class schools had a higher risk of infection than children attending upper-class schools.ConclusionTuberculosis infection is still a public health problem in Ghana and to monitor the trend, the survey needs to be repeated at 5 years interval.

Tuberculosis and non-tuberculous mycobacteria among HIV-infected individuals in Ghana

To assess the prevalence and clinical importance of previously unrecognised tuberculosis (TB) and isolation of non‐tuberculous mycobacteria (NTM) among HIV‐infected individuals in a teaching hospital in Ghana.

First Susceptibility Testing of Mycobacterium tuberculosis for Second-line Anti-tuberculosis Drugs in Ghana

We performed drug susceptibility testing on first- and second-line drugs in Mycobacterium tuberculosis (M. tuberculosis) for the first time in Ghana to obtain preliminary data on drug-resistant tuberculosis. Of 21 isolates (4 new cases and 17 treated cases), 5 (23.8%) were multi-drug resistant tuberculosis (MDR-TB) and 19 (90.5%) were resistant to at least one drug, but no extensively drug-resistant TB (XDR-TB) was identified. Since the target patients were Category II, IV or smear positive at follow-up microscopy, it is understandable that there were many drug-resistant TB cases. Six isolates were resistant to one or two second-line drugs, but the second-line drugs were not approved in Ghana. It is considered that the bacilli were imported from abroad. Preventing the import of drug-resistant TB bacilli is probably one of best ways to control TB in Ghana.

Molecular strain typing of the yaws pathogen, Treponema pallidum subspecies pertenue

Yaws is a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue. The disease primarily affects children under 15 years of age living in low socioeconomic conditions in tropical areas. As a result of a renewed focus on the disease owing to a recent eradication effort initiated by the World Health Organization, we have evaluated a typing method, adapted from and based on the enhanced Centers for Disease Control and Prevention typing method for T. pallidum subsp. pallidum, for possible use in epidemiological studies. Thirty DNA samples from yaws cases in Vanuatu and Ghana, 11 DNA samples extracted from laboratory strains, and 3 published genomic sequences were fully typed by PCR/RFLP analysis of the tpr E, G, and J genes and by determining the number of 60-bp repeats within the arp gene. Subtyping was performed by sequencing a homonucleotide “G” tandem repeat immediately upstream of the rpsA gene and an 84-bp region of tp0548. A total of 22 complete strain types were identified; two strain types in clinical samples from Vanuatu (5q11/ak and 5q12/ak), nine strain types in clinical samples from Ghana (3q12/ah, 4r12/ah, 4q10/j, 4q11/ah, 4q12/ah, 4q12/v, 4q13/ah, 6q10/aj, and 9q10/ai), and twelve strain types in laboratory strains and published genomes (2q11/ae, 3r12/ad, 4q11/ad, 4q12/ad, 4q12/ag, 4q12/v, 5r12/ad, 6r12/x, 6q11/af, 10q9/r, 10q12/r, and 12r12/w). The tpr RFLP patterns and arp repeat sizes were subsequently verified by sequencing analysis of the respective PCR amplicons. This study demonstrates that the typing method for subsp. pallidum can be applied to subsp. pertenue strains and should prove useful for molecular epidemiological studies on yaws.

First Nationwide Survey on the Resistance to First Line Anti-Tuberculosis Drugs in Ghana

Background/objective: A nationwide survey on the resistance to first line anti-tuberculosis (anti-TB) drugs was conducted in Ghana from 2007-2008 by Noguchi Memorial Institute for Medical Research in collaboration with the National Tuberculosis Control Programme. We aimed to characterize mycobacterial species causing pulmonary tuberculosis (PTB) and determine the resistance pattern to first line anti-TB drugs among newly diagnosed and previously treated PTB patients in Ghana. Methods: Two sputum samples from consented new smear positive PTB patients who had never been treated for TB or had been on anti-TB treatment for less than a month and patients who had been treated for TB previously for more than a month in selected diagnostic centres nationwide were collected for culture, identification and drug susceptibility test. Culture positive isolates were tested against streptomycin (S), isoniazid (H), rifampicin (R) and ethambutol (E) using the simplified proportion method and line probe assay (LPA). The LPA was performed in mid-2017. Results: Among 410 samples, 345 positive cultures were obtained and identified as Mycobacterium tuberculosis complex (MTBC). Of the 345 isolates, 133 were further differentiated by GenoType MTBC® as M. tuberculosis, 126 (94.7%) and M. africanum 7 (5.3%). The overall drug resistance patterns were as follows: 43/345 (12.5%), 6/345 (1.7%), 9/345 (2.6%) and 71/345 (20.6%) were resistant to H, R, E and S respectively and 5/345 (1.4%) were multi-drug resistant (MDR). Conclusion: The results indicate high levels of resistance to S and H among new and previously treated TB patients. We recommend adequate surveillance systems including periodic national anti-TB drug resistance surveys.