Abstract

Objective

The objective of this study was to determine the proportion of extended spectrum β-lactamase producing gram-negative bacteria (ESBL-GNB) colonizing patients admitted at Mazimbu hospital and Morogoro Regional hospital, in Morogoro, Tanzania. Rectal colonization with ESBL-GNB increases the risks of developing bacterial infections by extra-intestinal pathogenic ESBL-GNB.

Results

Of the 285 patients investigated, 123 (43.2%) carried ESBL-GNB in their intestines. Five of the 123 ESBL positive patients were colonized with two different bacteria, making a total of 128 ESBL producing isolates. Escherichia coli (n = 95, 74.2%) formed the majority of ESBL isolates. The proportion of CTX-M-1 group genes among ESBL isolates tested was 94.9% (93/98). History of antibiotic use (OR: 1.83, 95% CI: 1.1–3.2, P = 0.03), being on antibiotic treatment (OR: 2.61, 95% CI: 1.5–4.53, P = 0.001), duration of hospital stay (OR: 1.2, 95% CI: 1.1–1.3, P < 0.001) and history of previous admission (OR: 2.24, 95% CI: 1.2–4.1, P = 0.009) independently predicted ESBL-GNB carriage.

Introduction

Extended spectrum beta-lactamases (ESBLs) production, is the commonest mechanism of resistance to multiple broad-spectrum beta-lactams among gram-negative bacteria mainly members of the family Enterobacteriaceae [1, 2]. ESBL enzymes hydrolyze beta-lactam ring of the beta-lactams making these antibiotics ineffective against ESBL producing bacteria [3]. The blaCTX-M group out of other ESBL groups, is the commonest reported group of ESBL genes in different part of the World including in Tanzania [2, 4,5,6,7]. CTX-M enzymes effectively hydrolyzes third generation cephalosporins (3GCs) e.g., ceftriaxone and cefotaxime but not oxyimino-cephalosporins e.g., ceftazidime [8]. Although, some CTX-M members; CTX-M-15, -16 and -19 have been reported to hydrolyze ceftazidime activity [9,10,11].

Colonization with ESBL producing gram-negative bacteria (ESBL-GNB) increases the risk of developing multidrug resistant (MDR) bacterial infections e.g., bloodstream infection, urinary tract infection or wound infection [12]. Infections with MDR bacteria are associated with increased days of hospitalization, healthcare costs and mortalities from treatment failure and/or limited therapeutic options [13].

In Tanzania, previous studies from national and zonal referral hospitals have reported magnitudes of rectal/intestinal carriage of ESBL producing gram-negative bacteria (ESBL-GNB) ranging from 15% to 59.7% among hospitalized patients [14,15,16,17]. ESBL producing E. coli (ESBL-EC) and ESBL producing K. pneumoniae (ESBL-KP) are frequently reported with proportion ranging from 30% to 68.7% and 28.2% to 77.1%, respectively [14, 15, 17]. The magnitude of ESBL rectal colonization and associated factors among hospitalized patients in other tiers of the healthcare facilities like regional and district hospitals has not been well studied in developing countries including Tanzania. The objectives of this study was to determine the magnitude and factors associated with rectal colonization with ESBL producing gram-negative bacteria (ESBL-GNB) among hospitalized patients at Mazimbu hospital and Morogoro Regional hospital in Morogoro, Tanzania. Therefore, this study’s findings provide baseline information to improve measures of infections prevention and control (IPC).

Keywords: Antimicrobial stewardship; ESBL colonization; ESBL genes; Infection prevention and control