In Vitro Antifungal Resistance of Candida auris Isolates from Bloodstream Infections, South Africa.

Candida auris is a multidrug-resistant fungal pathogen that is endemic in South African hospitals. We tested bloodstream C. auris isolates that were submitted to a reference laboratory for national laboratory-based surveillance for candidemia in 2016 and 2017. We confirmed the species identification by phenotypic/molecular methods. We tested susceptibility to amphotericin B, anidulafungin, caspofungin, micafungin, itraconazole, posaconazole, voriconazole, fluconazole, and flucytosine using broth microdilution and Etest methods. We interpreted MICs using tentative breakpoints. We sequenced the genomes of a subset of isolates and compared them to the C. auris B8441 reference strain. Of 400 C. auris isolates, 361 (90%) were resistant to at least one antifungal agent, 339 (94%) to fluconazole alone (MICs of ≥32 µg/ml), 19 (6%) to fluconazole and amphotericin B (MICs of ≥2 µg/ml), and 1 (0.3%) to amphotericin B alone. Two (0.5%) isolates from a single patient were pan-resistant (resistant to fluconazole, amphotericin B, and echinocandins). Of 92 isolates selected for whole-genome sequencing, 77 clustered in clade III, including the pan-resistant isolates, 13 in clade I, and 2 in clade IV. Eighty-four of the isolates (91%) were resistant to at least one antifungal agent; both resistant and susceptible isolates had mutations. The common substitutions identified across the different clades were VF125AL, Y132F, K177R, N335S, and E343D in ERG11; N647T in MRR1; A651P, A657V, and S195G in TAC1b; S639P in FKS1HP1; and S58T in ERG3. Most South African C. auris isolates were resistant to azoles, although resistance to polyenes and echinocandins was less common. We observed mutations in resistance genes even in phenotypically susceptible isolates.

An outbreak of cutaneous abscesses caused by Panton-Valentine leukocidin-producing methicillin-susceptible Staphylococcus aureus among gold mine workers, South Africa, November 2017 to March 2018.

BACKGROUND: We aimed to describe an outbreak of cutaneous abscesses caused by Panton-Valentine leukocidin (PVL)-producing methicillin-susceptible Staphylococcus aureus (MSSA) among gold mine workers. METHODS: In February 2018, we retrospectively reviewed a random sample of 50 medical records from 243 cases and conducted face-to-face interviews using a structured questionnaire. Pus aspirates were sent to the National Institute for Communicable Diseases from prospectively-identified cases (November 2017-March 2018). Nasopharyngeal swabs were collected during a colonisation survey in February 2018. Staphylococcus aureus isolates were screened with a conventional PCR for lukS/F-PV. Pulsed-field gel electrophoresis (PFGE) was performed to determine the genetic relatedness among the isolates. A sample of isolates were selected for whole genome sequencing (WGS). We conducted an assessment on biological risks associated with mining activities. RESULTS: From January 2017 to February 2018, 10% (350/3582) of mine workers sought care for cutaneous abscesses. Forty-seven medical files were available for review, 96% were male (n = 45) with a mean age of 43 years (SD = 7). About 52% (24/46) were involved in stoping and 28% (13/47) worked on a particular level. We cultured S. aureus from 79% (30/38) of cases with a submitted specimen and 14% (12/83) from colonisation swabs. All isolates were susceptible to cloxacillin. Seventy-one percent of S. aureus isolates (30/42) were PVL-PCR-positive. Six PFGE clusters were identified, 57% (21/37) were closely related. WGS analysis found nine different sequence types. PFGE and WGS analysis showed more than one cluster of S. aureus infections involving closely related isolates. Test reports for feed and product water of the mine showed that total plate counts were above the limits of 1000 cfu/ml, coliform counts > 10 cfu/100 ml and presence of faecal coliforms. Best practices were poorly implemented as some mine workers washed protective clothing with untreated water and hung them for drying at the underground surface. CONCLUSIONS: PVL-producing MSSA caused an outbreak of cutaneous abscesses among underground workers at a gold mining company. To our knowledge, no other outbreaks of PVL-producing S. aureus involving skin and soft tissue infections have been reported in mining facilities in South Africa. We recommend that worker awareness of infection prevention and control practices be strengthened.

Screening for invasive fungal disease using non-culture-based assays among inpatients with advanced HIV disease at a large academic hospital in South Africa.

INTRODUCTION: Despite widespread access to antiretroviral therapy (ART), the burden of advanced HIV disease in South Africa is high. This translates into an increased risk of AIDS-related opportunistic infections, including invasive mycoses. METHODS: Using a limited number of non-culture-based diagnostic assays, we aimed to determine the prevalence of invasive mycoses and tuberculosis among hospitalised adults with very advanced HIV (CD4 counts < 100 cells/µL) at a large academic hospital. We conducted interviews and prospective medical chart reviews. We performed point-of-care finger stick and serum cryptococcal antigen lateral flow assays; serum (1 → 3) ß-D-glucan assays; urine Histoplasma galactomannan antigen enzyme immunoassays and TB lipoarabinomannan assays. RESULTS: We enrolled 189 participants from 5280 screened inpatients. Fifty-eight per cent were female, with median age 37 years (IQR: 30-43) and median CD4 count 32 cells/µL (IQR: 13-63). At enrolment, 60% (109/181) were receiving ART. Twenty-one participants (11%) had a diagnosis of an invasive mycosis, of whom 53% (11/21) had cryptococcal disease. Thirteen participants (7%) had tuberculosis and a concurrent invasive mycosis. ART-experienced participants were 60% less likely to have an invasive mycosis than those ART-naïve (adjusted OR: 0.4; 95% CI 0.15-1.0; P = .03). Overall in-hospital mortality was 13% (invasive mycosis: 10% [95% CI 1.2-30.7] versus other diagnoses: 13% (95% CI 8.4-19.3)). CONCLUSIONS: One in ten participants had evidence of an invasive mycosis. Diagnosis of proven invasive fungal disease and differentiation from other opportunistic infections was challenging. More fungal-specific screening and diagnostic tests should be applied to inpatients with advanced HIV disease.

Epidemiologic Shift in Candidemia Driven by Candida auris, South Africa, 2016-20171.

Candida auris is an invasive healthcare-associated fungal pathogen. Cases of candidemia, defined as illness in patients with Candida cultured from blood, were detected through national laboratory-based surveillance in South Africa during 2016-2017. We identified viable isolates by using mass spectrometry and sequencing. Among 6,669 cases (5,876 with species identification) from 269 hospitals, 794 (14%) were caused by C. auris. The incidence risk for all candidemia at 133 hospitals was 83.8 (95% CI 81.2-86.4) cases/100,000 admissions. Prior systemic antifungal drug therapy was associated with a 40% increased adjusted odds of C. auris fungemia compared with bloodstream infection caused by other Candida species (adjusted odds ratio 1.4 [95% CI 0.8-2.3]). The crude in-hospital case-fatality ratio did not differ between Candida species and was 45% for C. auris candidemia, compared with 43% for non-C. auris candidemia. C. auris has caused a major epidemiologic shift in candidemia in South Africa.

Large Outbreaks of Fungal and Bacterial Bloodstream Infections in a Neonatal Unit, South Africa, 2012-2016.

Candidemia is a major cause of healthcare-associated infections. We describe a large outbreak of Candida krusei bloodstream infections among infants in Gauteng Province, South Africa, during a 4-month period; a series of candidemia and bacteremia outbreaks in the neonatal unit followed. We detected cases by using enhanced laboratory surveillance and audited hospital wards by environmental sampling and epidemiologic studies. During July-October 2014, among 589 patients, 48 unique cases of C. krusei candidemia occurred (8.2% incidence). Risk factors for candidemia on multivariable analyses were necrotizing enterocolitis, birthweight <1,500 g, receipt of parenteral nutrition, and receipt of blood transfusion. Despite initial interventions, outbreaks of bloodstream infection caused by C. krusei, rarer fungal species, and bacterial pathogens continued in the neonatal unit through July 29, 2016. Multiple factors contributed to these outbreaks; the most functional response is to fortify infection prevention and control.

Molecular type distribution and fluconazole susceptibility of clinical Cryptococcus gattii isolates from South African laboratory-based surveillance, 2005-2013.

As is the case globally, Cryptococcus gattii is a less frequent cause of cryptococcosis than Cryptococcus neoformans in South Africa. We performed multilocus sequence typing (MLST) and fluconazole susceptibility testing of 146 isolates randomly selected from 750 South African patients with C. gattii disease identified through enhanced laboratory surveillance, 2005 to 2013. The dominant molecular type was VGIV (101/146, 70%), followed by VGI (40/146, 27%), VGII (3/146, 2%) and VGIII (2/146, 1%). Among the 146 C. gattii isolates, 99 different sequence types (STs) were identified, with ST294 (14/146, 10%) and ST155 (10/146, 7%) being most commonly observed. The fluconazole MIC50 and MIC90 values of 105 (of 146) randomly selected C. gattii isolates were 4 µg/ml and 16 µg/ml, respectively. VGIV isolates had a lower MIC50 value compared to non-VGIV isolates, but these values were within one double-dilution of each other. HIV-seropositive patients had a ten-fold increased adjusted odds of a VGIV infection compared to HIV-seronegative patients, though with small numbers (99/136; 73% vs. 2/10; 20%), the confidence interval (CI) was wide (95% CI: 1.93-55.31, p = 0.006). Whole genome phylogeny of 98 isolates of South Africa's most prevalent molecular type, VGIV, identified that this molecular type is highly diverse, with two interesting clusters of ten and six closely related isolates being identified, respectively. One of these clusters consisted only of patients from the Mpumalanga Province in South Africa, suggesting a similar environmental source. This study contributed new insights into the global population structure of this important human pathogen.

Culture-confirmed neonatal bloodstream infections and meningitis in South Africa, 2014-19: a cross-sectional study.

BACKGROUND: Few population-level estimates of invasive neonatal infections have been reported from sub-Saharan Africa. We estimated the national incidence risk, aetiology, and pathogen antimicrobial susceptibility for culture-confirmed neonatal bloodstream infections and meningitis in South Africa. METHODS: We conducted a cross-sectional study of neonates (<28 days of life) admitted to neonatal or paediatric wards of 256 public sector health facilities in South Africa during 2014-19. Diagnostic pathology records from Jan 1, 2014, to Dec 31, 2019, were extracted from a national pathology data warehouse. A case was defined as a neonate with at least one positive blood or cerebrospinal fluid culture during a 14-day period. Incidence risk was calculated using annual numbers of registered livebirths. Among the causative pathogens identified, we calculated the proportion of cases attributed to each of them, as well as the rates of antibiotic susceptibility of Gram-positive and Gram-negative bacteria. FINDINGS: Among 43 438 records of positive cultures, there were 37 631 incident cases of neonatal infection with at least one pathogen isolated. The overall incidence risk of culture-confirmed infections was 6·0 per 1000 livebirths (95% CI 6·0-6·1). The incidence risk of late-onset sepsis (days 3-27 of life) was 4·9 per 1000 livebirths (4·9-5·0) and that of early-onset sepsis (days 0-2 of life) was 1·1 per 1000 livebirths (1·1-1·1); risk ratio 4·4 (95% CI 4·3-4·5). The cause of infection differed by syndrome, timing of infection onset, facility, and province, although Klebsiella pneumoniae (26%), Acinetobacter baumannii (13%), and Staphylococcus aureus (12%) were the dominant pathogens overall. Gram-negative bacteria had declining susceptibility to most antibiotics over the study period. INTERPRETATION: We found a high incidence risk of late-onset sepsis with provincial variations, predominance of K pneumoniae, and declining antibiotic susceptibility among Gram-negative bacteria. This national surveillance in an upper-middle-income country provides a baseline burden of neonatal infections against which the impact of future clinical and public health interventions can be measured. FUNDING: Bill & Melinda Gates Foundation.

Genotype, Antifungal Susceptibility, and Virulence of Clinical South African Cryptococcus neoformans Strains from National Surveillance, 2005-2009.

In South Africa, Cryptococcus neoformans is the most common cause of adult meningitis. We performed multi locus sequence typing and fluconazole susceptibility testing of clinical C. neoformans isolates collected from 251 South African patients with cryptococcosis through national surveillance from 2005 to 2009. We examined the association between clinical characteristics of patients and genotype, and the effect of genotype on in-hospital mortality. We performed whole genome phylogenetic analysis of fifteen C. neoformans isolates with the molecular type VNB and tested their virulence in a Galleria mellonella model. Most isolates had the molecular type VNI (206/251, 82%), followed by VNII (25/251, 10%), VNB (15/251, 6%), and VNIV (5/251, 2%); 67 sequence types were identified. There were no differences in fluconazole minimum inhibitory concentration (MIC) values among molecular types and the majority of strains had low MIC values (MIC50 of 1 µg/mL and MIC90 of 4 µg/mL). Males were almost twice as likely of being infected with a non-VNI genotype (adjusted odds ratio [OR]: 1.65, 95% confidence interval [CI]: 0.25-10.99; p = 0.61). Compared to patients infected with a VNI genotype, those with a non-VNI genotype had a 50% reduced adjusted odds of dying in hospital (95% CI: 0.03-7.57; p = 0.62). However, for both these analyses, our estimates had wide confidence intervals spanning 1 with large p-values. Fifteen VNB strains were not as virulent in a G. mellonella larval model as the H99 reference strain. A majority of these VNB strains belonged to the VNBII clade and were very closely related by phylogenetic analysis.

Federation of Infectious Diseases Societies of Southern Africa guideline: Recommendations for the detection, management and prevention of healthcare-associated Candida auris colonisation and disease in South Africa.

Candida auris has been detected at almost 100 South African hospitals, causing large outbreaks in some facilities, and this pathogen now accounts for approximately 1 in 10 cases of candidaemia. The objective of this guideline is to provide updated, evidence-informed recommendations outlining a best-practice approach to prevent, diagnose and manage C. auris disease in public- and private-sector healthcare settings in South Africa. The 18 practical recommendations cover five focus areas: laboratory identification and antifungal susceptibility testing, surveillance and outbreak response, infection prevention and control, clinical management and antifungal stewardship.