Extended spectrum beta-lactamase mediated resistance in carriage and clinical gram-negative ESKAPE bacteria: a comparative study between a district and tertiary hospital in South Africa

Gram-negative ESKAPE bacteria are increasingly implicated in several difficult-to-treat infections in developed and developing countries. They are listed by the World Health Organization as resistant bacteria of critical priority in research.

To determine the risk factors, prevalence, phenotypic profiles, genetic diversity and clonal relatedness of extended-spectrum β-lactamase (ESBL)-producing multi-drug resistant (MDR) Gram-negative ESKAPE bacteria in the faecal carriage and clinical samples from patients in an urban, tertiary and a rural, district hospital in uMgungundlovu District, KwaZulu-Natal, South Africa.

This study took place in a district and tertiary hospital during a two-months period from May to June 2017 in uMgungundlovu district, South Africa. Rectal swabs collected from hospitalized patients, at admission, after 48 h and at discharge (whenever possible) formed the carriage sample while clinical isolates routinely processed in the microbiological laboratory during the sampling period were also collected and formed the clinical sample. Gram-negative ESKAPE bacteria were screened for ESBL production on selective MacConkey agar and confirmed using ROSCO kits. Minimum inhibitory concentrations were determined, and real-time and multiplex polymerase chain reaction were used to ascertain the presence of bla_CTX-M group-1-2-9, bla_CTX-M group 8/25, bla_SHV, bla_TEM, bla_OXA-1-like, bla_KPC, bla_VIM, bla_IMP, bla_GES and AmpC genes. Genomic fingerprinting was also performed using ERIC-PCR. Risk factors for ESBL-mediating MDR Gram-negative ESKAPE colonization were ascertained by univariate and multivariate logistic regression analyses.

Overall prevalence of carriage of ESBL-mediating MDR Gram-negative ESKAPE was 37.21% (16/43), 42.31% (11/26) and 57.14% (4/7) at admission, after 48 h and at discharge respectively. The prevalence of ESBL-mediating MDR Gram-negative ESKAPE bacteria in faecal carriage (46%) was higher than clinical samples (28%). Colonization was mainly associated with the referral from district to tertiary hospital with high statistical significance (OR: 14.40, 95% CI 0.98–210.84). bla_{CTX-M-group-9}, bla_{CTX-M-group-1} and bla_SHV were the main resistance genes identified. Several patients carried more than two different isolates. A Klebsiella pneumoniae (K1) clone was circulating within wards and between hospitals.

The study highlights the high prevalence of ESBL-mediating MDR Gram-negative ESKAPE bacteria in carriage and clinical samples among hospitalized patients in uMgungundlovu, South Africa. The wide dissemination of these resistant ESKAPE bacteria in hospitals necessitates improvements in routine screening and reinforcement of infection, prevention and control measures.