Intestinal carriage of colistin-resistant Enterobacteriaceae at Saint Georges Hospital in Lebanon.

OBJECTIVES: The increase in resistance to antibiotics has led to the revival of colistin as the last option for treatment, which automatically led to an increase of colistin-resistant, Gram-negative bacteria. In this study, we report the presence of clinical colistin-resistant Enterobacteriaceae isolated from a Lebanese hospital. METHODS: From 23 rectal swabs, eight colistin-resistant clinical strains (five Escherichia coli, two Enterobacter cloacae, and one Klebsiella pneumoniae) were isolated. Antibiotic susceptibility testing was performed using the disk diffusion method and Etest. The broth microdilution method was used to determine colistin susceptibility. Reverse transcription polymerase chain reaction (RT-PCR), standard PCR and sequencing were used to investigate genes encoding for extended-spectrum ß-lactamases, carbapenemases and colistin resistance. Genotyping of these isolates was conducted by multilocus sequence typing (MLST). RESULTS: Results of antibiotic susceptibility testing revealed that all isolates were resistant to colistin. They had MICs for colistin that ranged from 8 to 32 mg/L. Real-time PCR results showed that five strains harboured blaTEM-1 and one strain harboured blaTEM-163. Moreover, four strains were positive for blaCTX-M-15, blaCTX-M-103 and blaCTX-M-189, and K. pneumoniae harboured blaSHV-1. Observed colistin resistance was linked to amino acid substitutions into protein sequences of pmrA/B, phoP/Q, and mgrB. Interestingly, we report here a mutation in the mgrB regulator and pmrA/B, phoP/Q in colistin-resistant E. cloacae and E. coli clinical isolates for the first time in Lebanon. CONCLUSION: This study highlights the presence of colistin-resistant Gram-negative bacteria in a Lebanese hospital, which is worrisome. An urgent strategy needs to be adopted to avoid the spread of such bacteria.

Investigation of urban birds as source of ß-lactamase-producing Gram-negative bacteria in Marseille city, France.

BACKGROUND: We investigate here the presence of multidrug-resistant bacteria isolated from stool samples of yellow-legged gulls and chickens (n = 136) in urban parks and beaches of Marseille, France. Bacterial isolation was performed on selective media, including MacConkey agar with ceftriaxone and LBJMR medium. Antibiotic resistance genes, including extended-spectrum ß-lactamases (ESBL) (i.e. blaCTX-M, blaTEM and blaSHV), carbapenemases (blaKPC, blaVIM, blaNDM, blaOXA-23, blaOXA-24, blaOXA-48 and blaOXA-58) and colistin resistance genes (mcr-1 to mcr-5) were screened by real-time PCR and standard PCR and sequenced when found. RESULTS: Of the 136 stools samples collected, seven ESBL-producing Gram-negative bacteria (BGN) and 12 colistin-resistant Enterobacteriaceae were isolated. Among them, five ESBL-producing Escherichia coli and eight colistin-resistant Hafnia alvei strains were identified. Four blaTEM-1 genes were detected in yellow-legged gulls and chickens. Three CTX-M-15 genes were detected in yellow-legged gulls and pigeons, and one CTX-M-1 in a yellow-legged gull. No mcr-1 to mcr-5 gene were detected in colistin-resistant isolates. Genotyping of E. coli strains revealed four different sequence types already described in humans and animals and one new sequence type. CONCLUSIONS: Urban birds, which are believed to have no contact with antibiotics appear as potential source of ESBL genes. Our findings highlight the important role of urban birds in the proliferation of multidrug-resistant bacteria and also the possible zoonotic transmission of such bacteria from wild birds to humans.

Investigation of multidrug-resistant ST2 Acinetobacter baumannii isolated from Saint George hospital in Lebanon.

BACKGROUND: Acinetobacter baumannii is an opportunistic pathogen causing various nosocomial infections. The spread of multidrug-resistant A. baumannii is a major public health problem. The aim of this study was to investigate the molecular epidemiology and the genetic support of multidrug-resistant A. baumannii isolates collected from Saint-Georges Hospital in Lebanon. METHODS: Between January and August 2016, 31 A. baumannii isolates were collected from sputum samples of patients infected with ventilator-associated pneumonia (VAP) and treated with colistin-carbapenem combination therapy. Antibiotic susceptibility testing was performed using the disk diffusion method. Carbapenemases, extended spectrum ß-lactamases encoding genes and mcr-1/2 genes were investigated by RT-PCR and standard PCR. The epidemiological relatedness of the strains was studied using MLST analysis. RESULTS: Most of the isolates exhibited multidrug-resistant phenotypes. All the isolates were carbapenem-resistant and among them, 30 carried the class D carbapenemase blaoxa-23 gene while one isolate carried blaoxa-72 gene. MLST results revealed three sequence types, namely ST2, ST699, and ST627. Isolates having ST2 were the most prevalent clone (29/31, 93.5%). CONCLUSIONS: This study shows a nosocomial spread of multidrug-resistant A. baumannii ST2 having blaOXA-23 gene in Saint-George in Lebanon. Monitoring and control measures need to be adopted to avoid the spread of A. baumannii to patients.

Prevalence and Emergence of Extended-Spectrum Cephalosporin-, Carbapenem- and Colistin-Resistant Gram Negative Bacteria of Animal Origin in the Mediterranean Basin.

In recent years, extended ESBL and carbapenemase producing Gram negative bacteria have become widespread in hospitals, community settings and the environment. This has been triggered by the few therapeutic options left when infections with these multi-drug resistant organisms occur. The emergence of resistance to colistin, the last therapeutic option against carbapenem-resistant bacteria, worsened the situation. Recently, animals were regarded as potent antimicrobial reservoir and a possible source of infection to humans. Enteric Gram negative bacteria in animals can be easily transmitted to humans by direct contact or indirectly through the handling and consumption of undercooked/uncooked animal products. In the Mediterranean basin, little is known about the current overall epidemiology of multi-drug resistant bacteria in livestock, companion, and domestic animals. This review describes the current epidemiology of ESBL, carbapenemase producers and colistin resistant bacteria of animal origin in this region of the world. The CTX-M group 1 seems to prevail in animals in this area, followed by SHV-12 and CTX-M group 9. The dissemination of carbapenemase producers and colistin resistance remains low. Isolated multi-drug resistant bacteria were often co-resistant to non-beta-lactam antibiotics, frequently used in veterinary medicine as treatment, growth promoters, prophylaxis and in human medicine for therapeutic purposes. Antibiotics used in veterinary medicine in this area include mainly tetracycline, aminoglycosides, fluoroquinolones, and polymyxins. Indeed, it appears that the emergence of ESBL and carbapenemase producers in animals is not related to the use of beta-lactam antibiotics but is, rather, due to the co-selective pressure applied by the over usage of non-beta-lactams. The level of antibiotic consumption in animals should be, therefore, re-considered in the Mediterranean area especially in North Africa and western Asia where no accurate data are available about the level of antibiotic consumption in animals.

Prevalence of extended-spectrum ß-lactamase- and carbapenemase-encoding genes in poultry faeces from Algeria and Marseille, France.

OBJECTIVES: The aim of this study was to evaluate the prevalence of extended-spectrum ß-lactamase (ESBL)- and carbapenemase-encoding genes in poultry from Algeria and Marseille, France. METHODS: Samples consisted of faeces collected from broilers in France and Algeria between 2014 and 2015. DNA extraction and quantitative PCR were performed on 833 faecal samples to screen for the presence of genes encoding ESBLs (blaTEM, blaSHV and blaCTX-M) and carbapenemases (blaNDM, blaVIM, blaKPC, blaOXA-23, blaOXA-24, blaOXA-48 and blaOXA-58). To characterise bacteria carrying antimicrobial resistance genes, positive results were simultaneously sequenced. RESULTS: All chicken faeces from Marseille were negative for ESBL- and carbapenemase-encoding genes. However, of the 503 faecal samples collected in Algeria, 128 (25.4%) were positive for blaTEM, 83 (16.5%) for blaSHV, 46 (9.1%) for blaCTX-M and 132 (26.2%) for blaOXA-58. Using a sequencing reaction, a high diversity of ESBL genes was observed throughout the sites studied. CONCLUSIONS: This study shows a high prevalence and diversity of ESBL and carbapenemase genes in poultry faeces from Algeria, whereas none of the samples from Marseille were positive for these genes. The high prevalence of ESBLs in Algeria is in contrast to the observation that no chickens were found to be positive in France.

Prevalence and clonal relationship of ESBL-producing Salmonella strains from humans and poultry in northeastern Algeria.

BACKGROUND: The aims of this study were to investigate Salmonella contamination in broiler chicken farms and slaughterhouses, to assess the antibiotic resistance profile in avian and human Salmonella isolates, and to evaluate the relationship between avian and human Extended Spectrum ß-Lactamase (ESBL)-producing isolates. Salmonella was screened in different sample matrices collected at thirty-two chicken farms and five slaughterhouses. The human isolates were recovered from clinical specimens at the University Teaching Hospital of Constantine (UTH). All suspected colonies were confirmed by MALDI-TOF (Matrix Assisted Laser Desorption Ionization Time OF light) and serotyped. Susceptibility testing against 13 antibiotics including, amoxicillin/clavulanic acid, ticarcillin, cefoxitin, cefotaxime, aztreonam, imipenem, ertapenem, gentamicin, amikacin, ciprofloxacin, colistin, trimethoprim/sulfamethoxazole and fosfomycin, was performed using the disk diffusion method on Mueller-Hinton agar. ESBL-production was screened by the double-disk synergy test and confirmed by molecular characterization using PCR (polymerase chain reaction) amplification and sequencing of ESBL encoding genes. Clonality of the avian and human strains was performed using the Multi Locus Sequencing Typing method (MLST). RESULTS: Forty-five isolated avian Salmonella strains and 37 human collected ones were studied. Five S. enterica serotypes were found in avian isolates (mainly Kentucky) and 9 from human ones (essentially Infantis). 51.11% and 26.6% of the avian isolates were resistant to ciprofloxacin and cefotaxime, respectively, whereas human isolates were less resistant to these antibiotics (13.5% to ciprofloxacin and 16.2% to cefotaxime). Eighteen (12 avian and 6 human) strains were found to produce ESBLs, which were identified as bla CTX-M-1 (n = 12), bla CTX-M-15 (n = 5) and bla TEM group (n = 8). Interestingly, seven of the ESBL-producing strains (5 avian and 2 human) were of the same ST (ST15) and clustered together, suggesting a common origin. CONCLUSION: The results of the combined phenotypic and genotypic analysis found in this study suggest a close relationship between human and avian strains and support the hypothesis that poultry production may play a role in the spread of multidrug-resistant Salmonella in the human community within the study region.