Phenotypic and genotypic characterization of multidrug-resistant Acinetobacter baumannii isolated in Algerian hospitals.

INTRODUCTION: The aim of this study was to investigate the drug-resistance and the molecular characterization of carbapenemases, ESBL, and aminoglycoside-modifying enzymes among Acinetobacter baumannii clinical isolates in Algerian hospitals. METHODOLOGY: A total of 92 A. baumannii isolates were collected between 2012 and 2016. Antimicrobial susceptibility testings were performed for ß-lactams, aminoglycosides, fluoroquinolones, trimethoprim-sulfamethoxazole, rifampicin and colistin. The phenotypic characterization of ß-lactamases was investigated. For 30 randomly targeted strains, the carriage of the carbapenemases, ESBL and aminoglycoside-modifying enzymes -encoding genes was determined by PCR. Sequencing was carried out for carbapenemases and ESBL genes. RESULTS: Most of the 92 isolates studied were recovered from hospitalized patients (93.5%) and were mainly from intensive care units (51.1%) and orthopedics (19.6%). The strains were collected primarily from low respiratory tract (33.7%), wounds (23.9%) and urine (16.3%). Multidrug-resistant A. baumannii strains were prevalent (96.7%). High rates of resistance were observed for almost all antibiotics tested (>70%) excluding rifampicin (7.6%) and colistin (5.4%). For the five colistin-resistant strains, MICs ranged between 4 and 128 µg/mL. Positive MBL (83.7%) and ESBL (23.9%) strains were identified. Regarding ß-lactams, the blaNDM and both blaSHV and blaCTX-M1 genes were detected in five and two strains respectively. Sequencing of the genes revealed the presence of blaNDM-1, blaCTX-M-15, and blaSHV-33. For aminoglycosides, aac(6')-Ib, ant(2'')-I and aph(3')-VI genes were detected in three, seven and six strains respectively. CONCLUSIONS: Here, we report the first co-occurrence of extended-spectrum ß-lactamases SHV-33 and CTX-M-15, the carbapenemase NDM-1 and the emergence of colistin-resistant A. baumannii in Algerian hospitals.

Frequency and susceptibility pattern of uropathogenic Enterobacteriaceae isolated from patients in Algiers, Algeria.

INTRODUCTION: The frequency of Enterobacteriaceae involved in urinary tract infections (UTI) has increased significantly since the early 1990s, particularly in at-risk facilities such as resuscitation, surgery, urology and nephrology. The objective of this study was to evaluate the antimicrobial susceptibility of Enterobacteriaceae causing urinary tract infections (UTIs)at the University Hospital Centre of Benimessous in Algiers. METHODOLOGY: The study was designed as a retrospective study (between January 1st 2010 and December 31st 2012) and a prospective study (between January 1standApril 30th 2013) on 13,611 urine samples. Antimicrobial resistance phenotyping was conducted on the bacterial isolates using disk-diffusion method. RESULTS: On 13,611 urine samples analysed, 1,790 (13.15%) fulfilled the criteria for urinary tract infection. Enterobacteriaceae were identified in 1,561 analysed samples (87%). Escherichia coli was the dominant uropathogen (66,15%) in both hospitalized and non-hospitalized patients. The other main detected Enterobacteriaceae members were Klebsiella pneumoniae (11,96%) and Proteus mirabilis (5,42%). Analysis of results showed also that women were more prone to UTI than men with sex ratio of 3.76(W/M). The susceptibilities of isolated Enterobacteriaceae to antibiotics revealed that they had acquired resistance to several classes, particularly toward ß-lactams. Resistance frequencies were relatively high to ampicillin and sulfomethoxasole, while being very low to aminoglycosides and furans. Results obtained revealed also that 7% of isolates where resistant to third generation cephalosporins by production of extended spectrum ß-lactamases (ESBL). CONCLUSIONS: The continuous monitoring of antibiotic resistance of uropathogenic Escherichia coli is crucial to guide the clinician to choose the best empiric treatment.

High prevalence of multidrug-resistance in Acinetobacter baumannii and dissemination of carbapenemase-encoding genes blaOXA-23-like, blaOXA-24-like and blaNDM-1 in Algiers hospitals.

OBJECTIVE: To assess and characterize antibiotic resistance in Acinetobacter baumannii strains recovered from 5 health-care facilities in Algiers. METHODS: Antibiotic susceptibility testing was performed by agar diffusion and agar dilution methods, resistance genes were identified by PCR and sequencing, and molecular typing of isolates was carried out by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR). RESULTS: Among 125 tested isolates, 117 (93.6%) were multidrug-resistant, of which 94 (75.2%) were imipenem resistant. The blaADC and blaOXA-51-like genes were detected in all isolates, in association with ISAba1 sequence in 84% and 8% (imipenem resistant) of isolates, respectively. The blaOXA-23-like and blaOXA-24-like carbapenemase genes were detected in 67.02% and 20.21% of imipenem-resistant isolates, respectively. The blaOXA-23-like gene is linked to ISAba1 or ISAba4 elements. The metallo-ß-lactamase NDM-1 gene was found in 10 (10.6%) imipenem-resistant strains from three hospitals, it is linked to ISAba125 element in nine strains. Extended spectrum ß-lactamases production was not detected. Imipenem and cefotaxime resistance phenotypes could not be transferred to Escherichia coli by conjugation. Outer membrane protein CarO gene was not detected in four imipenem-resistant isolates. The aac(6')-Ib, sul1, sul2, tetA and tetB genes were present in 5.31%, 36.17%, 77.65%, 1.06% and 65.92% of strains, respectively. Class 1 integrons were detected in 23.4% strains. ERIC-PCR typing showed a genetic diversity among blaOXA-23-like and blaOXA-24-like positive strains, while clonality was observed among blaNDM-1 positives. CONCLUSIONS: This study highlighted the high prevalence of imipenem resistance in Acinetobacter baumannii in Algiers hospitals mediated mainly by blaOXA-23-like, blaOXA-24-like, and blaNDM-1 genes.

Emergence of Colistin- and Carbapenem-Resistant Acinetobacter baumannii ST2 Clinical Isolate in Algeria: First Case Report.

AIM: The aim of this study was to investigate the prevalence and the mechanisms of carbapenem and colistin resistance in Acinetobacter baumannii clinical isolates in an Algerian hospital. RESULTS: Twelve isolates were collected between October 2013 and March 2014. All isolates were resistant to almost all antibiotics tested with a high-level resistance to imipenem (minimum inhibitory concentrations [MICs] >32 mg/L) with one strain showing resistance to colistin (MIC=16 mg/L). The results of the modified Hodge test and the modified Carba NP test were positive for all isolates. Besides, the activity of ß-lactamases was inhibited by EDTA in only two isolates. All the 12 isolates contained the naturally occurring blaOXA-51-like gene. Ten of them harbored the OXA ß-lactamases: blaOXA-23 (six isolates) and blaOXA-24 (four isolates) genes, while two isolates were positive for blaNDM-1 gene. The colistin-resistant isolate producing OXA-24 enzyme harbored a single mutation in the pmrB gene. Multilocus sequence typing demonstrated that the 12 isolates belonged to 2 clones: 10 to ST2 and 2 to ST85. CONCLUSIONS: Here, we describe the mechanisms of carbapenem resistance and we report the first colistin and carbapenemase-producing A. baumannii clinical isolate from a patient in Algeria.

[Emergence of glycopeptide resistant Enterococcus faecium in Algeria: a case report]. / Émergence d'Enterococcus faecium résistant aux glycopeptides en Algérie : à propos d'un cas.

A glycopeptide-resistant Enterococcus faecium (EFRG) was isolated from a wound in a patient hospitalized in a university hospital in Algiers. This strain was resistant to several antibiotics. This patient was carrying this strain in the digestive tract which may partly explain its origin. Genotypic comparison of the two strains by pulsed field gel electrophoresis showed that it was the same strain. Glycopeptide resistance was due to the presence of the vanA gene. Vigilance is required facing the emergence of strains of EFRG in our hospitals.

Prevalence of plasmid-mediated AmpC beta-lactamases among Enterobacteriaceae in Algiers hospitals.

The aim of this study was to investigate the prevalence and diversity of plasmid-mediated AmpC cephalosporinases (PAcBLs) in clinical isolates of Enterobacteriaceae collected between 2003 and 2007 from three Algiers hospitals. Antibiograms were determined on Mueller-Hinton agar plates using the disk diffusion method, and minimum inhibitory concentrations were determined by Etest. Isolates resistant to cefoxitin or ceftazidime were screened for bla(CMY), bla(DHA), bla(FOX) and bla(ACC) as well as extended-spectrum beta-lactamase (ESBL) genes by polymerase chain reaction (PCR). PCR products were sequenced by the Sanger method. Plasmid incompatibility grouping was conducted by PCR-based replicon typing. The prevalence of PAcBLs was 2.18% (11/505), comprising 8 CMY-2 and 3 DHA-1 enzymes. CTX-M-15 was co-produced with CMY-2 in three isolates and with DHA-1 in one isolate; the two remaining DHA-1-producers co-expressed SHV-12 ESBL. This is the first report of plasmid-mediated AmpC from Algeria, with the first detection of DHA-1 in Enterobacter cloacae.

Dissemination of ESBL and Qnr determinants in Enterobacter cloacae in Algeria.

OBJECTIVES: The aim of this study is to evaluate the prevalence and diversity of extended-spectrum beta-lactamases (ESBLs) in Enterobacter cloacae clinical isolates collected from Algerian hospitals and to verify the association with qnr genes. METHODS: MICs were determined by Etest for isolates giving positive double-disc synergy tests, and all isolates were screened by PCR and sequenced, respectively, for bla(TEM), bla(CTX-M), bla(SHV) and bla(VEB) genes and for qnr genes (qnrA, qnrB, qnrS), using specific primers. RESULTS: The prevalence of ESBLs was 25/141 (17.7%) with 11, 9, 4 and 1 isolates testing positive for genes encoding CTX-M-15, CTX-M-3, SHV-12 and VEB-1, respectively. Two SHV-12 producers and one CTX-M-15 producer expressed QnrS1, one isolate produced CTX-M-15 and QnrB1 and one SHV-12 producer co-expressed QnrS1 and QnrB4. qnrA was not detected in our collection, and qnr alleles were not detected in non-ESBL-producing isolates. CONCLUSIONS: SHV-12, QnrS1, QnrB1 and QnrB4 were reported for the first time in Algeria. This study also described a co-expression of qnrS1 and qnrB4 by an SHV-12 producer isolate.