Molecular epidemiology of carbapenem-resistant Pseudomonas aeruginosa clinical strains isolated from western Algeria between 2009 and 2012

Acinetobacter baumannii Carbapenemase Producers in Morocco: Genetic Diversity

INTRODUCTION

 Carbapenem resistance in Acinetobacter baumannii (A. baumannii) is a public health problem worldwide. Although carbapenem resistance is emerging in Morocco, few studies have shown the epidemiological profile of carbapenemase genes in Moroccan healthcare facilities. The aim of this study was to characterize the molecular profile of the carbapenemase enzyme in Acinetobacter baumannii from clinical isolates.

METHODS

Clinical strains isolated in the laboratory from various samples were subjected to several phenotypic tests. Antibiotic susceptibility and identification were tested using Phoenix 100 (Becton Dickinson Co., Sparks, MD, USA) and Api 20 (bioMérieux, Marcy-l'Etoile, France). Simple phenotypic assays were used to detect carbapenemase oxacillinase (OXA) and metallo-β-lactamase (MBL) production, including the modified Hodge test (MHT) and ethylenediaminetetraacetic acid (EDTA) test. The detection of carbapenemase genes was performed by multiplex and simple polymerase chain reaction (PCR).

RESULTS

A total of 140 strains or 100% of isolates contained OXA-51 and ISbA1 sequences, 89% contained OXA-23 and OXA-58 sequences, and 1% contained OXA-24 sequence. The MBL genes were predominated by Verona integron-encoded metallo-β-lactamase (VIM) (56%), followed by Seoul imipenemase (SIM) (39%), German imipenemase (GIM) (37%), São Paulo metallo-β-lactamase (SPM) (13%), imipenemase (IMP) (11%), and New Delhi metallo-β-lactamase (NDM) (4%). Guyana extended-spectrum β-lactamase (GES) was not found in any isolation.

CONCLUSION

Our study shows a high frequency of carbapenem resistance in Acinetobacter baumannii, as it reports a high molecular diversity of carbapenemase-encoding genes, mainly dominated by the carbapenemase ISaba1/OXA-23, which represents an emerging threat in our hospital.

Epidemiology, Phenotypic and Genotypic Characterization of Carbapenem-Resistant Gram-Negative Bacteria from a Libyan Hospital

Antimicrobial resistance, particularly resistance to carbapenems, has become one of the major threats to public health. Seventy-two isolates were collected from patients and hospital environment of Ibn Sina Hospital, Sirte, Libya. Antibiotic susceptibility tests, using the disc diffusion method and E-Test strips, were performed to select carbapenem-resistant strains. The colistin (CT) resistance was also tested by determining the minimum inhibitory concentration (MIC). RT-PCR was conducted to identify the presence of carbapenemase encoding genes and plasmid-mediated mcr CT resistance genes. Standard PCR was performed for positive RT-PCR and the chromosome-mediated CT resistance genes (mgrB, pmrA, pmrB, phoP, phoQ). Gram-negative bacteria showed a low susceptibility to carbapenems. Molecular investigations indicated that the metallo-β-lactamase New Delhi metallo-beta-lactamases-1 was the most prevalent (n = 13), followed by Verona integron-encoded metallo-beta-lactamase (VIM) enzyme (VIM-2 [n = 6], VIM-1 [n = 1], and VIM-4 [n = 1]) that mainly detected among Pseudomonas spp. The oxacillinase enzyme OXA-23 was detected among six Acinetobacter baumannii, and OXA-48 was detected among one Citrobacter freundii and three Klebsiella pneumoniae, in which one coharbored the Klebsiella pneumoniae carbapenemase enzyme and showed resistance to CT (MIC = 64 μg/mL) by modification in pmrB genes. In this study, we report for the first time the emergence of Pseudomonas aeruginosa carrying the bla_NDM-1 gene and belonging to sequence type773 in Libya. Our study reported also for the first time CT resistance by mutation in the pmrB gene among Enterobacteriaceae isolates in Libya.

Antimicrobial Resistance Among Gram-Negative Bacteria Isolated in the Newborn Intensive Care Unit at ABDERREZAK-BOUHARA Hospital of Skikda, Algeria

Background: This study aimed to determine the epidemiology of gram-negative bacteria (GNB) isolated in the newborn intensive care unit (NICU) population, to assess their antibiotic susceptibility patterns and possible associated risk factors. Methods: All neonates admitted to the NICU of ABDERREZAK-BOUHARA hospital (Skikda, Algeria) with a clinical diagnosis of neonatal infections from March to May 2019 were included in the study. The extended-spectrum β-lactamase (ESBLs), plasmidic cephalosporinase (pAmpC), and carbapenemases genes were screened by polymerase chain reaction (PCR) and sequencing. PCR amplification of oprD among carbapenem-resistant Pseudomonas aeruginosa isolates was also performed. The clonal relatedness of the ESBLs isolates was studied using multilocus sequence typing (MLST). Results: Among 148 clinical specimens, 36 (24.3%) GNB strains were isolated from urine (n = 22), wound (n = 8), stool (n = 3), and blood (n = 3) samples. The bacterial species identified were Escherichia coli (n = 13), Klebsiella pneumoniae (n = 5), Enterobacter cloacae (n = 3), Serratia marcescens (n = 3), Salmonella spp. (n = 3), Proteus mirabilis (n = 1), P. aeruginosa (n = 5), and Acinetobacter baumannii (n = 3). PCR and sequencing showed that eleven Enterobacterales isolates harbored the bla_CTX-M-15 gene, two E. coli isolates harbored the bla_CMY-2 gene, and three A. baumannii isolates harbored both bla_OXA-23 and bla_OXA-51 genes. Also, five strains of P. aeruginosa were found to harbor mutations in the oprD gene. MLST showed that the K. pneumoniae strains belonged to ST13 and ST189, E. coli belonged to ST69, and E. cloacae belonged to ST214. Different risk factors that could predict positive GNB cultures were found, including female sex, Apgar score <8 at 5 min of life, enteral nutrition, antibiotic use, and extended length of hospitalization. Conclusion: Our study highlights the importance of determining the epidemiology of pathogens causing neonatal infections, their sequence types (ST), and their antibiotic susceptibility patterns to address rapidly a correct antibiotic treatment regimen.

High Carbapenem Resistance Caused by VIM and NDM Enzymes and OprD Alteration in Nonfermenter Bacteria Isolated from a Libyan Hospital

Acinetobacter baumannii and Pseudomonas aeruginosa are among the most prevalent pathogens causing a wide range of serious infections in hospitalized patients and contaminating intensive care units and inanimate surfaces. The purpose of this study was to investigate the mechanism of carbapenem resistance in clinical and hospital environmental isolates of A. baumannii and P. aeruginosa recovered from a Libyan hospital. From a total of 82 Gram-negative bacteria, 8 isolates of A. baumannii and 3 isolates of P. aeruginosa exhibited resistance to imipenem with minimum inhibitory concentrations ranging from 16 to >32 μg/mL. Five isolates of A. baumannii harbored bla_OXA-23 gene, from which three isolates were collected from patients and two from hospital environment. Only one isolate harbored bla_NDM-1 gene, which was responsible for carbapenem resistance in A. baumannii. The OprD gene seems to be disturbed by an insertion sequence (IS) in two isolates and affected by polymorphism in one isolate. Pulsed-field gel electrophoresis results showed high genetic diversity among carbapenemase producing A. baumannii. This study highlights the dissemination of bla_OXA-23 and bla_NDM-1 genes in a Libyan setting. Therefore, infection prevention and control practices, antimicrobial stewardship initiatives, and antimicrobial resistance surveillance systems should be implemented to prevent the wide spread of antimicrobial resistance.

Characterization of antibiotic resistance profiles in Pseudomonas aeruginosa isolates from burn patients

OBJECTIVE

To investigate the prevalence of multidrug-resistant (MDR) Pseudomonas aeruginosa (PA) producing extended-spectrum beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) in burn patients in Algeria.

METHODS

Between April 2016 and October 2019, 47 non-redundant isolates of PA were collected from 47 burn patients admitted to the Department of Burns at the Military Hospital of Algiers in Algeria. Antibiotic susceptibility testing was performed by agar diffusion and the Phoenix automated method. Resistance genes were identified by PCR, and molecular typing of isolates was carried out by enterobacterial repetitive intergenic consensus (ERIC) sequences-polymerase chain reaction (PCR).

RESULTS

Among the 47 non-redundant MDR PA strains isolated, 59.57% were phenotypically ESBLs-positive, and 100% were phenotypically MBL-positive. The ESBL-positive isolates were subsequently screened for six groups of bla genes encoding ESBL-type enzymes, namely blaCTX-M2, blaPER, blaTEM, blaSHV, blaVEB, and blaGES. Out of the 28 ESBL-producing strains, 23 (82.14%) were blaCTX-M2 positive; 18 (38.29%) were blaPER positive, and 16 (34.04%) were blaTEM positive, while 5 (17.9%) were co-harboring blaCTX-M2, blaTEM, and blaPER genes. The blaSHV, blaVEB, and blaGES genes were not detected in any of the ESBL positive isolates. Since all isolates were MBL-positive, all 47 strains were screened for the blaNDM-1, blaIMP, blaVIM genes that produce MBLs; however, none of these genes were detected. Additional screening for the oprD gene demonstrated that 45 (95.74%) of the isolates were positive for this gene. Finally, ERIC PCR revealed 11 distinct PA clones among the blaCTX-M2 positive strains.

CONCLUSION

This is the first study to report the presence of CTX-M2-producing PA in the North Africa region and the first to detect blaCTX-M2-positive and blaPER-positive PA clinical isolates in Algeria, therefore demonstrating the spread of such MDR strains to this part of the world. Identification of bacterial genotypic alterations that confer antibiotic resistance is critical in determining the most effective antimicrobial strategies to be employed. Therefore, our findings could potentially facilitate clinical decision making regarding the antibiotics of choice for the treatment of burn patients that suffer from PA infections in Algeria.

Carbapenemase-Producing Non-Glucose-Fermenting Gram-Negative Bacilli in Africa, Pseudomonas aeruginosa and Acinetobacter baumannii: A Systematic Review and Meta-Analysis

Background

Studies have reported that the existence of CP bacteria in Africa, but, in general, comprehensive data about the molecular epidemiology of CP organisms are limited. Therefore, this systematic review and meta-analysis expound the pooled prevalence of CP P. aeruginosa and CP A. baumannii clinical isolates in Africa. It also identified the diversity of carbapenemases or their encoding genes among the isolates in Africa. Lastly, the review observed the trends of these CP isolates in Africa.

Methods

A comprehensive search was performed between July 2019 and October 2019 in the following databases: PubMed, Google Scholar, and African Journal online. The included articles were published only in English. The screening was done by two authors independently. The data extracted on Excel spreadsheet were transferred to STATA 11 software for analysis.

Results

From a total of 1,454 articles searched, 42 articles were eligible. Most of the studies were conducted in the North Africa region. But there was no report from Central Africa. The pooled prevalence of CP P. aeruginosa and CP A. baumannii among the clinical specimens in Africa was 21.36% and 56.97%, respectively. OXA-23 and VIM were the most prevailing carbapenemase among P. aeruginosa and A. baumannii, respectively. The cumulative meta-analysis revealed a relative increment of the prevalence of CP P. aeruginosa over time in Africa but it showed a higher prevalence of CP A. baumannii isolates across years.

Conclusion

The review revealed a high pooled prevalence of CP A. baumannii clinical isolates in Africa which needs urgent action. Moreover, the emergence of concomitant carbapenemases, especially OXA-23 +  NDM among CP A. baumannii, was also an alarming problem.

Characterization of VIM-4 Producing Clinical Pseudomonas aeruginosa Isolates from Western Algeria: Sequence Type and Class 1 Integron Description

Objectives: Pseudomonas aeruginosa occupies a central position in nosocomial infections and remains a significant cause of morbidity and mortality. The aim of this study was to characterize carbapenem resistance mechanisms in P. aeruginosa isolates from clinical specimens collected at the University Hospital of Oran, western Algeria. Materials and Methods: The identification of 214 nonduplicated P. aeruginosa isolates (collected from January to December 2016) was confirmed using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Thirteen antibiotics were tested using the disc diffusion method. Carbapenemase-encoding genes were detected with the GeneXpert system and multiplex polymerase chain reaction (PCR). Clonal relatedness was determined using multilocus sequence typing (MLST) and the seven housekeeping genes were further used for phylogenetic analysis of imipenem-resistant P. aeruginosa using concatenated gene fragments. The flanking regions of the bla_VIM-4 gene were analyzed by whole-genome sequencing. Results: Eleven isolates (5.39%) were resistant to carbapenems. PCR amplification and sequencing showed that six of these isolates (2.94%) harbored the bla_VIM-4 gene that was carried on a novel class 1 integron. MLST analysis assigned the tested isolates to seven different sequence types (STs), of which two were new (ST3349 and ST3350) and five were previously described (ST244, ST499, ST709, ST809, and ST1239). Conclusion: In this study, we reported P. aeruginosa isolates producing VIM-4 in an Algerian hospital. The bla_VIM-4 is harbored in class 1 integron with a new arrangement of genes cassettes.

Role of Institut Hospitalo-Universitaire Méditerranée Infection in the surveillance of resistance to antibiotics and training of students in the Mediterranean basin and in African countries

Surveillance of antibiotic resistance has become a public global concern after the rapid worldwide dissemination of several antibiotic resistance genes. Here we report the role of the Institut Hospitalo-Universitaire Méditerranée Infection created in 2011 in the identification and description of multidrug-resistant bacteria thanks to collaborations and training of students from the Mediterranean basin and from African countries. Since the creation of the institute, 95 students and researchers have come from 19 different countries from these areas to characterize 6359 bacterial isolates from 7280 samples from humans (64%), animals (28%) and the environment (8%). Most bacterial isolates studied were Gram-negative bacteria (n = 5588; 87.9%), mostly from Algeria (n = 4190), Lebanon (n = 946), Greece (n = 610), Saudi Arabia (n = 299) and Senegal (n = 278). Antibiotic resistance was diversified with the detection and characterization of extended-spectrum β-lactamases, carbapenemases and resistance to colistin, vancomycin and methicillin. All those studies led to 97 indexed international scientific papers. Over the last 6 years, our institute has created a huge network of collaborations by training students that plays a major role in the surveillance of resistance to antibiotics in these countries.

Epidemiology of common resistant bacterial pathogens in the countries of the Arab League

No uniformly organised collection of data regarding antimicrobial resistance has occurred in the countries of the Arab League. 19 countries of the Arab League have published data for antimicrobial susceptibility for the WHO priority organisms, and seven of 14 of these organisms are included in this Review (Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Acinetobacter baumannii, Salmonella spp, Staphylococcus aureus, and Streptococcus pneumoniae). Although E coli and Klebsiella spp resistance to third-generation cephalosporins is common in all countries, with prevalence reaching more than 50% in Egypt and Syria, carbapenem resistance is emerging, albeit with a prevalence of less than 10%. Conversely, a large amount of carbapenem resistance has been reported for P aeruginosa and A baumannii across the Arab League, reaching 50% and 88% of isolates in some countries. As for Salmonella spp, the prevalence of fluoroquinolone resistance has exceeded 30% in several areas. With regards to the Gram-positive pathogens, the prevalence of meticillin resistance in S aureus is reported to be between 20% and 30% in most countries, but exceeds 60% in Egypt and Iraq. The prevalence of penicillin non-susceptibility among pneumococci has reached more than 20% in Algeria, Egypt, Morocco, Saudi Arabia, and Tunisia. These findings highlight the need for structured national plans in the region to target infection prevention and antimicrobial stewardship.

Molecular characterization of carbapenem-resistant Gram-negative bacilli clinical isolates in Algeria

Objectives

The aims of this study were to investigate the occurrence of carbapenem-resistant Gram-negative bacilli (GNB) isolated from inpatients and outpatients in Algeria between July and September 2015, and to screen their resistance mechanisms and genetic relatedness.

Materials and methods

A total of 68 non-redundant isolates were identified using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) antibiotic susceptibility testing was performed using disk diffusion and Etest methods. Carbapenemase activity was carried out using modified Carba NP test, EDTA assay, and the modified Hodge test. Molecular characterization of carbapenemases and extended-spectrum β-lactamase (ESBL) genes were detected by standard PCR and sequencing. Genotyping of carbapenem-resistant isolates was performed by multilocus sequence typing (MLST) analysis.

Results

Of the 68 GNB isolates, 13 (19%) showed reduced susceptibility to carbapenems, including, four Klebsiella pneumoniae, one Escherichia coli, six Acinetobacter baumannii, and two Pseudomonas aeruginosa. bla_OXA-48 gene was detected in the five Enterobacteriaceae isolates, and bla_OXA-23 was identified in all A. baumannii isolates. OprD mutations were revealed in the two P. aeruginosa isolates. A total of 11 out of the 13 carbapenem-resistant GNB were detected in inpatients, and the two remaining strains were isolated from outpatients. Molecular typing showed the presence of four sequence types (STs) among the OXA-48-producing K. pneumoniae isolates: ST101, ST147, ST163, and ST2017. ST533 was identified for the OXA-48 producing E. coli isolate. All of the A. baumannii and P. aeruginosa were assigned to the international clonal lineages ST2 and ST654, respectively.

Conclusion

This study reports the first detection of the epidemic multidrug-resistant lineage, K. pneumoniae ST147 coproduced bla_OXA-48 and ESBL genes in Algeria and represents the first description of OXA-48-producing E. coli ST533 and K. pneumoniae ST163 and ST2017. In addition, this study describes for the first time the emergence of OXA-48-producing E. coli and K. pneumoniae in the community in Algeria, leading to major problems for managing microbial infections.

Molecular epidemiology of environmental and clinical carbapenemase-producing Gram-negative bacilli from hospitals in Guelma, Algeria: Multiple genetic lineages and first report of OXA-48 in Enterobacter cloacae

This study was designed to investigate environmental colonisation in Algerian hospitals by carbapenem-resistant Gram-negative bacilli (GNB), including molecular characterisation of their resistance, and to perform a comparative molecular analysis between clinical and environmental strains. GNB isolated from hospitalised patients and the hospital environment were identified using microbiological methods and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antibiotic susceptibility testing was performed by disk diffusion and Etest methods. Carbapenemase- and extended-spectrum β-lactamase (ESBL)-encoding genes were searched for using PCR and sequencing. Clonality of the environmental and clinical strains was assessed by multilocus sequencing typing (MLST). A total of 32 carbapenem-resistant GNB were isolated, including 16 (29%) of 56 multidrug-resistant (MDR) GNB from clinical specimens and 16 (48%) of 33 MDR-GNB from inanimate surfaces. Of the 32 carbapenem-resistant isolates, 14 produced a carbapenemase. The bla_OXA-48 gene was detected both in clinical and surface isolates of Klebsiella pneumoniae (n=3) and Enterobacter cloacae (n=2). Clinical and surface isolates of Acinetobacter baumannii were found to produce the carbapenemases NDM-1 (7 isolates) and OXA-23 (2 isolates). MLST revealed clonal diversity and a relationship between environmental and clinical strains with identical sequence types. Here we report the first description of an OXA-48-producing E. cloacae isolate in Algeria. We also highlight the important role of inanimate surfaces in the spread of carbapenem-resistant bacteria and the emergence of nosocomial infections.

Diverse Genetic Background of Multidrug-Resistant Pseudomonas aeruginosa from Mainland China, and Emergence of an Extensively Drug-Resistant ST292 Clone in Kunming

For a better understanding of the multidrug resistant Pseudomonas aeruginosa (MDR-PA) epidemiology in mainland China, a nationwide surveillance network of 27 tertiary hospitals was established. Non-duplicate MDR-PA isolates from 254 cases of nosocomial infections, were collected during the period August 2011 to July 2012. Minimum inhibitory concentrations (MICs) of nine antimicrobial agents were determined by broth micro-dilution method according to the CLSI guidelines [M7-A10]. Genotyping analysis was performed by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). The presence of acquired carbapenemases was also determined by molecular approaches for 233 carbapenem-resistant isolates. Carbapenemase genes were detected in 19 (8.2%) isolates, with 13 of these isolates encoding IMP-type enzymes, five with VIM-2, and one with KPC-2. MLST analysis revealed significant genetic diversity among the MDR-PA isolates studied, and 91 STs (including 17 novel STs) were identified. However, a long-term outbreak of an emerging extensively drug-resistant (XDR) ST292/PFGE genotype A clone was detected in a hospital from Southwest China. This study has demonstrated that MDR-PA in mainland China have evolved from diverse genetic backgrounds. Evidence of clonal dissemination of the organism and nosocomial outbreaks in some regions, suggest a need to strengthen existing infection control measures.

Epidemiology and virulence of VIM-4 metallo-beta-lactamase-producing Pseudomonas aeruginosa isolated from burn patients in eastern Algeria

In this study, we investigated the prevalence of carbapenem-resistant Pseudomonas aeruginosa (CRPA) in burn patients from eastern Algeria, CRPA virulence factors and the molecular epidemiology of CRPA. The overall prevalence of CRPA was 48.38%. Seven (46.66%) isolates were metallo-β-lactamases (MBL) producers and contained the MBL genes blaVIM-4 (n=6) and blaVIM-2 (n=1). Risk factors for CRPA infection were urinary catheter use and intubation (p=0.008). A high percentage of virulence factors (86.6% of these isolates were able to produce protease; 73.3% of isolates has DNase; and 66.6% were haemolysin positive) was observed in CRPA isolates. Among the seven MBL-producing isolates, four had the same clonal profile. The class 1 integrons, which contained the aadA7 gene cassette, were detected in six isolates. The 16SrRNA methylase gene, rmtB, was detected in one strain. All CRPA isolates were biofilm formers. A study on the kinetics of biofilm production revealed that biofilm production increased when the concentration of imipenem or ciprofloxacin and the incubation time increased. This is the first study to report the presence of VIM-4-producing P. aeruginosa from North Africa and also of the high prevalence of CRPA isolates. Based on our study of burn unit patients, the high percentage of P. aeruginosa with virulence factors and multi-drug resistance is alarming.

First report of VIM-2 metallo-β-lactamases producing Pseudomonas aeruginosa isolates in Morocco

The emergence and the rapid spread of Pseudomonas aeruginosa carrying carbapenemases represent a serious threat to public health due to their delicate therapy. This work was performed to establish the resistance profile and to detect carbapenemases producing in 123 P. aeruginosa isolates. Among these 55 are environmental isolates and 68 are from the two major hospitals of Meknes-Tafilalet region in Morocco. All strains were tested against 14 antipseudomonal drugs by disc diffusion method. On carbapenem resistant strains minimum inhibitory concentrations of imipenem were determined by the E-test method. The modified Hodge test and EDTA tests were used for the detection of carbapenemases and metallo-β-lactamases (MBLs), respectively. PCR and DNA sequencing were conducted to detect carbapenemase-encoding genes and the enzyme types. 12% of isolates was susceptible to all antibiotics tested and Carbapenem resistance was observed in 33 P. aeruginosa isolates, 33.3% of them were multi-drug resistant. Among carbapenem resistant strains only two (6.1%) were positive for carbapenemases and also for MBLs. In addition to their resistance to almost all β-lactams tested, the MBLs producing strains were resistant to aminoglycosides. Molecular biology techniques confirmed the phenotypic results obtained for the two strains carbapenemase producers and demonstrated that each one of them carried blaVIM-2. The present study reports the first isolation of blaVIM genes in clinical isolates of P. aeruginosa in Morocco. Such isolates represent a serious emerging threat requiring strict hygiene measures to better control their spread.

Epidemiology and Characteristics of Metallo-β-Lactamase-Producing Pseudomonas aeruginosa

Metallo-β-lactamase-producing Pseudomonas aeruginosa (MPPA) is an important nosocomial pathogen that shows resistance to all β-lactam antibiotics except monobactams. There are various types of metallo-β-lactamases (MBLs) in carbapenem-resistant P. aeruginosa including Imipenemase (IMP), Verona integron-encoded metallo-β-lactamase (VIM), Sao Paulo metallo-β-lactamase (SPM), Germany imipenemase (GIM), New Delhi metallo-β-lactamase (NDM), Florence imipenemase (FIM). Each MBL gene is located on specific genetic elements including integrons, transposons, plasmids, or on the chromosome, in which they carry genes encoding determinants of resistance to carbapenems and other antibiotics, conferring multidrug resistance to P. aeruginosa. In addition, these genetic elements are transferable to other Gram-negative species, increasing the antimicrobial resistance rate and complicating the treatment of infected patients. Therefore, it is essential to understand the epidemiology, resistance mechanism, and molecular characteristics of MPPA for infection control and prevention of a possible global health crisis. Here, we highlight the characteristics of MPPA.

Epidemiology of carbapenem non-susceptible Pseudomonas aeruginosa isolates in Eastern Algeria

Background

Carbapenem resistance among Pseudomonas aeruginosa has become a serious life-threatening problem due to the limited therapeutic options. In this study, we investigated the prevalence and the molecular epidemiology of carbapenem resistant Pseudomonas aeruginosa (CRPA) isolated from three hospitals in Annaba city, Algeria.

Methods

During the study period (January, 2012 to December, 2013), all patients infected by P. aeruginosa were considered as the potential study population. Antibiotic susceptibility testing was performed as recommended by the CLSI. Screening of carbapenemase producer isolates was performed by using imipenem-EDTA double-disk synergy test and modified Hodge test. CRPA isolates were tested for the presence of genes encoding β-lactamases, plasmid mediated quinolone resistance, aminoglycoside resistance and class 1 integrons were investigated by PCR and sequencing. The clonal relatedness among CRPA isolates was analyzed by pulsed-field gel electrophoresis method. The clinical data were collected to identify risk factors for CRPA carriage of P. aeruginosa infection.

Results

The overall prevalence of CRPA was 18.75 %. The risk factors for carrying CRPA were the length of hospital stay (p = 0.04), co-infections with Staphylococcus aureus (p = 0.01), and the use of urinary catheter (p = 0.03). The in-hospital mortality rate among case patients was 13.33 % compared with 1.53 % for control patients (p = 0.09). All CRPA isolates were multidrug resistance and the most effective antibiotic against CRPA isolates was amikacin and colistin. PFGE revealed an epidemic clonal dissemination of CRPA isolates. None of CRPA isolated were found to be carbapenemase-producers. The bla_PSE-1 and aac(3)-II gene was detected in two and five strains respectively. The class1 integrons were detected in 2 isolates with the presence of aadA7 gene cassette in these integrons.

Conclusion

The endemic clonal dissemination and multi-drug resistance of CRPA isolates in our institution is highly alarming. Strict measure will be required to control the further spread of these pathogens in hospital setting.

The spread of carbapenemase-producing bacteria in Africa: a systematic review

BACKGROUND

Carbapenems are the last line of defence against ever more prevalent MDR Gram-negative bacteria, but their efficacy is threatened worldwide by bacteria that produce carbapenemase enzymes. The epidemiology of bacteria producing carbapenemases has been described in considerable detail in Europe, North America and Asia; however, little is known about their spread and clinical relevance in Africa.

METHODS

We systematically searched in PubMed, EBSCOhost, Web of Science, Scopus, Elsevier Masson Consulte and African Journals Online, international conference proceedings, published theses and dissertations for studies reporting on carbapenemase-producing bacteria in Africa. We included articles published in English or French up to 28 February 2014. We calculated the prevalence of carbapenemase producers only including studies where the total number of isolates tested was at least 30.

RESULTS

Eighty-three studies were included and analysed. Most studies were conducted in North Africa (74%, 61/83), followed by Southern Africa (12%, 10/83), especially South Africa (90%, 9/10), West Africa (8%, 7/83) and East Africa (6%, 6/83). Carbapenemase-producing bacteria were isolated from humans, the hospital environment and community environmental water samples, but not from animals. The prevalence of carbapenemase-producing isolates in hospital settings ranged from 2.3% to 67.7% in North Africa and from 9% to 60% in sub-Saharan Africa.

CONCLUSIONS

Carbapenemase-producing bacteria have been described in many African countries; however, their prevalence is poorly defined and has not been systematically studied. Antibiotic stewardship and surveillance systems, including molecular detection and genotyping of resistant isolates, should be implemented to monitor and reduce the spread of carbapenemase-producing bacteria.

Emergence of VIM-2 and IMP-15 carbapenemases and inactivation of oprD gene in carbapenem-resistant Pseudomonas aeruginosa clinical isolates from Lebanon

We report here the emergence of VIM-2 and IMP-15 carbapenemases in a series of clinical isolates of carbapenem-resistant Pseudomonas aeruginosa in Lebanon. We also describe the disruption of the oprD gene by either mutations or insertion sequence (IS) elements ISPa1328 and ISPre2 isoform. Our study reemphasizes a rapid dissemination of the VIM-2 carbapenemase-encoding gene in clinical isolates of P. aeruginosa in the Mediterranean basin.