Evolution of antimicrobial resistance in departments with high risk of cross infections in Tunisia

Background

Antimicrobial resistance is actually a real and ever-changing public health problem. The microbiology laboratory plays a key role to achieve collaboration with clinical services and the prevention and control of infection team.

Objective

Describe the bacterial ecology of departments with high risk of Health care associated infections and analyze the evolution of antimicrobial resistance.

Methods

A descriptive and retrospective study was carried out in the university hospital Sahloul. It concerned all strains isolated in departments with high risk of Health care associated infections. The study period was spread over 7 years from January 1st, 2010 to December 31th, 2016.

Results

A total of 6108 non-redundant bacterial strains were isolated. Isolated pathogens were mainly from the urology departement (n-2651, 43.4%).The most frequent isolated pathogens were Escherichia coli (n = 1329, 21,8%), K. pneumoniae (n = 992, 16,2%), and Acinetobacter baumannii (n = 763, 12,5%). Concerning these main isolated species, significant statistical differences were noticed in bacterial resistance evolution over the years. With E. coli, the evolution was essentially represented by an increase of amoxicillin, amoxicillin clavulanic, cefotaxime, gentamicin, and fluoroquinolones resistance. With K. pneumoniae, cefotaxime resistance was stable, however resistance to imipenem and gentamicin was increasing. There was also a significant increase in fluoroquinolone and aminoside resistance. With S. Aureus, an increase in methicillin resistance was detected from 11.1% in 2010 to 20% in 2016.

Conclusions

Antibacterial Drug Resistance is a dynamic and rapidly evolving phenomenon in our hospital. The most common MDR bacteria studied were enterobacteriaceae producing carbapenemase. The emergence of glycopeptid resistance in enterococci must be controlled in order to prevent its spread to the community and the transfer of staphylococcus resistance genes.

Key messages

Antibacterial Drug Resistance is a dynamic and rapidly evolving phenomenon in our hospital. The most common multi drug resistant bacteria studied were enterobacteriaceae producing carbapenemase.

The emerging extensively drug resistant bacteria in a university hospital in Tunisia in 2019

Background

The discovery of antibiotics revolutionized medicine in the 20th century, however the emergence of extensively drug-resistant bacteria constitute a growing problem in our hospitals in Tunisia and across the world. This study aims to evaluate a screening program for Carbapenemase Producing Enterobacteriaceae (CPE) and vancomycin-resistant enterococci (VRE) undertaken by the Microbiology Laboratory of Sahloul University Hospital.

Methods

A descrptive and retrospective study was carried out between 01st April 2018 and 31th December 2019 in the university hospital Sahloul, in East Coast of Tunisia. The screening was based on rectal swabs; it concerned Medical Intensive Care Units, the postoperative unit, the paediatric and the nephrology departments. The rectal swabs were seeded on the chromID CARBASMART and chromID VRE agars(biomerieux, France)in search of CPE and VRE respectively. The identification and the antibiotic susceptibilities testing were performed using the Vitek2 System (biomerieux,France)

Results

In total, 191 patients were screened. Among them, 56% were admitted in Intensive Care Units, 9.95% in postoperative unit, 30.9% in paediatric department and 3.14% in the nephrology department. A total of 38 extensively drug-resistant bacteria were isolated: 20 CPE and 18 VRE. Among isolated CPE, 17 were identified as Klebsiella pneumonia: The ConfirmationKPC/MBLkit (RoscoDiagnostica, Denmark) supplemented with a disc of Temocillin showed that 7 strains produced metallo-carbapenemase and 10 strains produced OXA 48 carbapenemase. The other isoloted CPE were OXA-48 producers. All VRE were identified as Enterococcus faecium, Their Vancomycin and Teicoplanine MICs were greater than 32 mg/L.

Conclusions

Mastering the spread of extensively drug-resistant bacteria involves a multidisciplinary preventive strategy. It must include strict application of hygiene measures, early detection and isolation of carriers and rationalization of antibiotic use.

Key messages

the emergence of extensively drug-resistant bacteria constitute a growing problem that`s why Carbapenemase Producing Enterobacteriaceae and vancomycin-resistant enterococci screening is crucial. Anti microbial agents use must be rationalized.

[Evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007)]

BACKGROUND

Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to determine the evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007).

MATERIAL AND METHODS

A total of 1503 stool samples collected from children less than five years old, consulting or hospitalised in Tunisia for diarrhoea between 2005 and 2007, were screened for the presence of group A Rotaviruses. Rotavirus-positive specimens were further analyzed by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR.

RESULTS

Rotaviruses were detected in 323 stool samples over 1503 (21 %). Long electropherotypes predominated in Tunisia during the whole period of study (N=158 vs N=82 short electropherotypes). VP7 genotyping showed the cocirculation of five different genotypes: G1, G2, G3, G4 and G9. VP4 typing detected four different P-genotypes: P[8], P[4], P[6] and P[11]. Rotavirus strains with G3P[8] specificity were predominating in Tunisia in 2005 and 2006, replaced by G2P[4] strains in 2007.

[Clinical and epidemiological characterization of infections due to imipenem resistant Acinetobacter baumannii at the university hospital Sahloul, Tunisia]

OBJECTIVE

to characterize epidemiological and clinical features related to the multi-drug Acinetobacter baumannii infections in the university hospital Sahloul in Tunisia.

MATERIAL AND METHODS

retrospective study including twenty-four imipenem resistant Acinetobacter baumannii isolated from twenty patients hospitalized in different wards of the hospital. Study of clinical features related to the infection by multi-drug Acinetobacter baumannii, bacterial identification by classical identification scheme, antibiotic susceptibilities were determined by the disk diffusion method; genotyping was performed by arbitrarily-primed PCR.

RESULTS

the most incriminated ward was the intensive care unit with a high prevalence of septicaemia. All studied strains were multi-drug to all beta-lactams tested. Genotyping has shown the clonality of studied strains. Features incriminated in the acquisition of infection were essentially immunodeficiency, invasive manoeuvring and antibiotherapy.

CONCLUSION

multidrug Acinetobacter baumannii is increasingly isolated in our hospital. Rational use of antibiotics and rigorous application of hygienic rules could contribute to limit dissemination of such strains.

Group A rotavirus strains circulating in the eastern center of Tunisia during a ten-year period (1995-2004)

An epidemiological survey investigating rotavirus infections in children was undertaken in the Eastern Center of Tunisia between January 1995 and December 2004. A total of 982 faecal specimens collected from children less than 5 years in age were screened by enzyme-linked immunosorbent assay (ELISA) or latex agglutination assay for the presence of group A rotavirus antigen. Rotavirus-positive samples were used for G and P typing by multiplex semi-nested reverse transcription-PCR. Rotaviruses were detected in 22% (n = 220) of stools. Of these, 164 were typed for VP7: G genotypes found were G1 (59%), G2 (2%), G3 (9%), G4 (10%), G8 (1%), and G9 (1%). Sixteen specimens (9%) showed mixed G profiles. A total of 119 specimens were typed for VP4. P genotypes detected were P[8] (32%), P[6] (15%), and P[4] (13%). Mixed P profiles were also detected (6%). Although the distribution of the detected genotypes appeared to change annually, G1P[8] rotavirus strains always predominated during the 10-year period of study. This is the first report of rotaviruses in Tunisia with unconventional VP7 serotypes such as G8 and G9, highlighting the need for continual surveillance of emerging strains in Northern Africa. Indeed, the new commercial vaccines only contain the VP7 genes that dictate G1 or G1 to G4 specificities. These vaccines may protect less well against unusual strains circulating in countries planning to implement a rotavirus vaccine strategy.

Syndrome opsoclonie–myoclonie associé à une infection à Mycoplasma pneumoniae

Mycoplasma pneumoniae infection is associated with various manifestations involving the central nervous system but it has never been reported as a potential aetiology of opsoclonus-myoclonus syndrome (OMS) in children.

OBSERVATION

We report on a case in a 4-year-old girl who presented neurological manifestations compatible with an OMS, after a respiratory tract disease. Aetiological investigations revealed M. pneumoniae infection as specific IgM were present in the serum (Elisa). Evolution after corticosteroid, intravenous immunoglobulins and macrolide therapy was favourable as clinical symptoms disappeared. After a 12-month follow-up, the patient has no neurological sequela.

CONCLUSION

M. pneumoniae infection should be added to the list of causes to be screened in OMS. Its pathophysiology remains unknown but may involve a dysimmune postinfectious mechanism.

[Prevalence of adenovirus antigens in children presenting with acute diarrhoea]

Viral diarrhoea remains a major cause of childhood morbidity and mortality worldwide. Four major categories of viruses are now recognized as clinically important, including rotavirus, astrovirus, adenovirus, and calicivirus. This retrospective epidemiological study was conducted in the East centre part of Tunisia. A total of 638 stool samples were collected from children under 5 years of age presenting with acute diarrhoea at hospitals the East centre part of Tunisia between October 2003 and September 2005. All samples were analyzed using commercially available immunoenzymatic assay (EIA) kits to detect specific adenovirus antigens. Samples positive for adenovirus antigen were further screened using an ELISA technique allowing specific detection of species F enteric adenovirus types 40 and 41. Adenovirus was detected in 6% of the stools tested using ELISA. Among stool samples testing positive for adenovirus, 57% (20/35) were found to contain species F adenovirus types 40/41. In addition to diarrhoea that was present in all children studied, vomiting and fever were observed in 89% and 53% respectively and were associated with respiratory troubles in 32%. Enteric adenoviruses appear to play an important role in paediatric diarrhoea in Tunisia. Use of simple effective viral diagnostic techniques in paediatric hospitals could improve patient care by reducing unnecessary use of antibiotics.

Identification of viral agents causing diarrhea among children in the Eastern Center of Tunisia

Viral diarrhea remains a major cause of childhood morbidity and mortality worldwide. In Tunisia, no comprehensive studies of all viral agents related to diarrhea in children have yet been conducted. The present study was performed to investigate the role of enteric viruses in acute diarrhea in the country. Six hundred thirty-eight stool samples were collected from children under 5 years of age seeking medical care for acute diarrhea between October 2003 and September 2005 in hospitals from the Eastern-Center Tunisia. All samples were tested for rotavirus, astrovirus, and adenovirus using commercial antigen enzyme immunoassays (EIAs). Positive samples for rotavirus and astrovirus were confirmed by an "in-house" reverse transcriptase-polymerase chain reaction (RT-PCR). Samples positive for adenovirus antigen were subjected to further EIA screening for species F enteric adenovirus types 40 and 41. At least one viral agent was found in 30% of the specimens. The frequency of rotavirus, astrovirus, and adenovirus was 20%, 7%, and 6%, respectively. Of the stool samples containing adenovirus, 57% (20/35) were found to be positive for species F adenovirus types 40/41. Dual infections were found in 9% (17/191) of the positive samples. Enteric viruses appear to play an important role in pediatric diarrhea in Tunisia. The introduction of affordable viral diagnosis in pediatric hospitals will improve patient care by reducing the unnecessary use of antibiotics.

[Molecular characterization of invasive Haemophilus influenzae strains isolated in Tunisia]

We reported a molecular characterization of 25 Haemophilus influenzae strains derived from cases of meningitis and sepsis in children aged less than five years hospitalized in pediatric wards from three hospitals in the Sahel area (Tunisia) during the period 1997-2002. These strains were biotyped and subjected to a capsular typing by Slide agglutination serotyping and Polymerase Chain Reaction (PCR). The genetic polymorphism of these strains was also studied in Arbitrarily Primed Polymerase Chain Reaction (AP-PCR) with two sets of primers: RAP IV and 217 delta(2) as in Pulsed Field Gel Electrophoresis after digestion of the total DNA with the restriction enzyme SmaI (PFGE SmaI). Nineteen strains among 25 (76%) were of biotype I. The bexA gene was highlighted in 13 strains (52%) and in all the cases it was of the type b. Twelve strains (48%) were shown to be unencapsulated by PCR. AP-PCR RAP IV (23 genotypes/25 with a discrimination index ID=0.993) had shown nearly the same discriminatory power than PFGE (20 genotypes/21 strains with a discrimination index ID=0.995). We thus note, how capsular typing by PCR is more sensitive than slide agglutination serotyping. We also note the genetic diversity of the invasive strains isolated with a remarkable presence of non typable strains. AP PCR seems to be an alternative of choice for the epidemiologic follow-up of the Haemophilus influenzae invasive infections.

[A rapid method of grouping beta-hemolytic streptococci using extemporaneous coagglutination]

Extemporaneous coagglutination procedure for the serological grouping of beta-hemolytic streptococci is reported. Streptococcal group antigens were extracted with nitrous acid. 250 strains of groups A, B, C, F and G streptococci were tested with this method. An agreement of 100% was found between this method and the Lancefield capillary precipitation procedure. Extemporaneous coagglutination method was found to be rapid, reliable, easy and economical and could be adopted in any routine diagnostic laboratory.

[Extraction of chromosomal DNA from Staphylococcus and Listeria by a rapid method using achromopeptidase]

A rapid and simple method for preparation of chromosomal DNA from Gram-positive bacteria is reported. Susceptibility to lysis with Sodium Dodecyl Sulfate (SDS) increases when undergoing treatment with acetone before being digested by bacteriolytic enzymes. Rapid lysis of Staphylococcus and Listeria cells is obtained through a respective treatment by lysozyme with lysostaphine and by lysozyme with achromopeptidase, adding to that the effect of SDS in Tris-Hcl buffer. This procedure of preparing chromosomal DNA provides 1 to 4 mg of DNA out of 1 g of bacterial cells in a day.

[Antibiotic resistance of Salmonella during 1982 and 1983]

The antibiotics susceptibility of 480 Salmonella collected in 1982 and 1983, in the National Center of Salmonella of Pasteur Institute of Tunis was tested. High levels of resistance were found. Nalidix acid, colistin and gentamicin were the most active. Resistance and multiple resistance was most frequently found in strains of Salmonella wien and Salmonella saint paul.

[Preliminary note on anti-insulin antibody formation in diabetics treated with porcine insulin]

In the present study, we have tested the sera of sixty five diabetic patients treated with insulin, researching the action of some physiologic and therapeutic factors (sex, age, insulin dose and time of treatment), to production of anti-insulin antibodies. Our results have shown that an important percentage of diabetic patients treated by porcine insulin produce antibodies: 72% of studied patients, concerning chiefly all the women and patients under-fourty years old. However our results have not pointed out any relation between the administered insulin dose versus the anti-insulin antibodies production, in spite of the early production of these antibodies in a great part of the patients.