Identification of VIM-2-Producing Pseudomonas aeruginosa from Tanzania Is Associated with Sequence Types 244 and 640 and the Location of bla _VIM-2 in a TniC Integron

Abstract

e Epidemiological data on carbapenemase-producing Gram-negative bacteria on the African continent are limited. Here, we report the identification of VIM-2-producing Pseudomonas aeruginosa isolates in Tanzania. Eight out of 90 clinical isolates of P. aeruginosa from a tertiary care hospital in Dar es Salaam were shown to harbor bla VIM-2 . The bla VIM-2 -positive isolates belonged to two different sequence types (ST), ST244 and ST640, with bla VIM-2 located in an unusual integron structure lacking the 3= conserved region of qac⌬E1-sul1. Pseudomonas aeruginosa is an opportunistic pathogen associated with a number of nosocomial infections. Carbapenems (i.e., meropenem and imipenem) are often the treatment of choice for infections caused by P. aeruginosa that is resistant to other antipseudomonal ␤-lactams (1). However, the emergence and spread of acquired carbapenemases, particularly metallo-␤-lactamases (MBLs), among P. aeruginosa are threatening the usefulness of carbapenems (2). Resistance to carbapenems in P. aeruginosa can also occur due to impermeability, efflux mechanisms, and other ␤-lactamases, including overexpression of the chromosomal AmpC (3).Several acquired MBLs have been identified in P. aeruginosa, including the VIM, IMP, SPM, GIM, AIM, FIM, and NDM enzymes (2, 4). The genes encoding these MBLs are associated with mobile genetic elements, such as insertion sequence common region (ISCR) elements, transposons, and plasmids, and as gene cassettes in integron structures. The dissemination of the various MBLs among P. aeruginosa isolates has been shown to occur in many different genetic backgrounds (5). However, two major clonal complexes (CC), CC235 and CC111, predominate, particularly with respect to the dissemination of VIM enzymes (5).On the African continent, an increasing number of reports indicates that MBL-producing, and in particular VIM-2-producing, P. aeruginosa is widespread in Africa. VIM-2-producing P. aeruginosa isolates have been observed in Tunisia (6-8), Kenya (9), the Ivory Coast (10), Algeria (11), and South Africa (12). Further, reports have shown the import of P. aeruginosa with VIM-2 from African countries (Ghana, Tunisia, and Egypt) into Europe (13-15).(Part of this study was presented at the 22nd European Congress of Microbiology and Infectious Diseases, 31 March to 3 April 2012, London, United Kingdom.)The aim of this study was to determine the occurrence and molecular epidemiology of MBL-producing P. aeruginosa isolates identified from clinical specimens at a tertiary hospital in Dar es Salaam, Tanzania. This was a cross-sectional study conducted at the Central Pathology Laboratory, Muhimbili National Hospital (MNH), Dar es Salaam, Tanzania. MNH is the largest tertiary health care facility in Tanzania and serves as a university teaching and referral hospital to the population of Dar es Salaam and the whole country. The study included 90 clinical isolates of P. aeruginosa consecutively collected from May 2010 to July 2011. Duplicate isolates were excluded from the study. Only i...

Opening Pandora’s box: high level resistance to antibiotics of last resort in Gram negative bacteria from Nigeria

“…Isolates of this sequence type have been seen in the UK[16], and have also been reported previously as carrying VIM-2 or IMP-1 in Norway (in an isolate thought to be imported from Ghana)[36], Japan[37], and South Africa[38]. The other P. aeruginosa sequence type identified in this study (ST244) is a globally disseminated P. aeruginosa clone identified in several countries, including Poland[39], Brazil[40], Spain[41], South Korea[42], the Czech Republic[43], Greece[44], Russia[45], China [46] and Tanzania[47]. ST244 isolates have been found to carry various carbapenemases including IMP and VIM enzymes as well as extended-spectrum ß-lactamases, such as PER-1 and VEB-1[39, 48].…”

Characterization of carbapenem resistance mechanisms and integrons in Pseudomonas aeruginosa strains from blood samples in a French hospital

“…However, to the best of our knowledge, there are no previous descriptions of these STs among P. aeruginosa isolates from blood samples. Among the diversity of STs found, ST175, ST233, ST235, ST244 and ST654 were noteworthy as high-risk clones that are frequently associated with carbapenemase producers (Samuelsen et al, 2010;Vatcheva-Dobrevska et al, 2013;Moyo et al, 2015;Wright et al, 2015). Table 3 shows the different patterns of virulence genes studied in the 56 IRPA strains.…”

Multi-drug resistance bacteria predict mortality in blood stream infection in a tertiary setting in Tanzania

“…Beside ESBL, we also observed MRSA and phenotypic 293 carbapenemase production in Pseudomonas aeruginosa and Proteus mirabilis. Carbapenemase 294 producing Pseudomonas aeruginosa have also been reported previously at our hospital (21). It is 295 worrying to note the growing resistance to carbapenems, which is the last effective therapy for 296 severe Gram-negative infections.…”