esbl has been found all over the world , and reviewing research has been done in europe ( 6 , 7 ) , north america ( 8) , and asia ( 9 ) in recent years to understand the extent of esbls and other multiresistant bacteria ; also , there are surveillance studies running in the same regions to guide the clinical treatment of infectious diseases . in europe
( during 19992008 ) , there has been an increase in invasive infections caused by klebsiella pneumoniae and escherichia coli resistant to third - generation cephalosporins , and this is believed to be due to the dissemination of esbls in both hospitals and communities . an increase in carbapenemase production among isolates
urinary tract isolates collected in the smart study between 2009 and 2010 concluded that in europe , esbl prevalence among e. coli and k. pneumoniae was 17.6 and 38.9% , respectively . in north america ,
the prevalence was 8.5 and 8.8% , respectively ( 11 ) . in asia , the prevalence of esbl among e. coli and k. pneumoniae varied between 5 and 0% , respectively , in new zealand and between 67 and 61% , respectively , in china ( 12 ) .
the class a esbl gene ctx - m-15 was the most common gene in the european and american settings ( found in > 90% of e. coli isolates and in 3565.5% of k. pneumoniae ) , but shv- and tem - type genes were also prevalent , between 1.7 and 42.9% , especially in k. pneumoniae ( 11 ) . from the sentry asia pacific surveillance program , ctx - m genes were found in 38.255.5% of k. pneumoniae and e. coli isolates , and the prevalence of shv- and tem - type genes was higher ( between 34.3 and 85.3% ) ( 13 ) .
in africa , the prevalence of esbl in enterobacteriaceae has been researched at local levels in various countries , but there is no summarizing research on how prevalent esbl is on the continent , what type of genes are involved , and where research is missing .
this review aims to describe the prevalence of esbl - producing enterobacteriaceae in hospital and community settings in africa and the esbl genes involved .
a literature search was conducted in pubmed in june 2013 with the keywords  africa , 
 extended - spectrum beta - lactamases. the search was limited to articles published in english , studying humans , and published from 2008/01/01 to 2012/12/31 . from the 91 references found ,
seven articles could not be accessed in online databases or acquired in paper copy , and they were excluded ; the remaining 84 articles were read in full text .
19 articles were excluded because they were not relevant for the aim of this study .
the excluded articles did not research esbl , studied countries outside of africa , or looked at other colonized hosts than humans .
the references were assessed in quality according to a value scale , modified from hedin et al .
( 14 ) , where the strength of evidence for different esbl genes and prevalence in the selected references were graded low , middle , and high based on the method of analyses used in the studies . as many of the studies reported
had used the same method , study size and what proportion of the sample was analyzed in detail were also taken into account to assess the strength of the scientific evidence ( table 1 ) .
this section is divided into regional areas of africa , according to the un regional composition ( 15 ) . for detailed descriptions of sample sizes , organisms , settings and prevalence , sources of samples , and esbl genes involved ,
class a esbls were most common , but plasmid - encoded ampc ( pampc ) was also present ( 1622 ) . in egypt , esbls were found in 1142.9% of samples in both hospitals and communities ; the genes involved were class a esbls ( 2325 ) . in guinea - bissau and libya , class a and d esbls and a carbapenemase
were found in 32.6 and 16% , respectively , in rectal or stool samples ( 26 , 27 ) . in morocco ,
class a and d esbls , pampc , and carbapenemases were found in hospital settings ( 2830 ) . in the community
setting , class a and d esbls were found in between 1.3 and 7.5% of acquired urine samples ( 3133 ) . in tunisia , class a and d esbls , pampc , and carbapenemases were present , and the prevalence ranged from 11.7 to 77.8% in hospitals and was 0.7 and 7.3% in two communities ( 3451 ) . in ethiopia and kenya , 62.8 and 37.4% , respectively , of hospital and community samples were esbls ( 52 , 53 ) .
class a esbls and pampc were present in the kenyan sample ( 53 . in samples taken from kenya and malawi , class
a and d esbls were found ( 54 ) . in rwanda , esbls were found in 38.3% of hospital urine samples and in 5.9% of community urine samples ( 55 ) . in tanzania ,
class a esbls were found in various samples from hospital settings ( 56 , 57 ) . in cameroon ,
class a and d esbls were found in 55.3 and 82.8% of hospital stool samples and in 17.2% of community stool samples ( 58 , 59 ) . in the central african republic , esbls were found in 11.3% of community urine samples ( 60 ) . in ghana and mali , class
a esbls were found in 49.4 and 63.496% , respectively , in hospital and community samples ( 6164 ) . in niger ,
40% of hospital samples carried class a esbls or pampc ( 65 ) . in nigeria ,
class a and d esbls and pampc were found in hospital settings , and the prevalence ranged from 10.3 to 27.5% ( 6671 ) . in a mixed sample from a hospital and a community ,
class a and d esbls were found in 10% of community stool samples ( 73 ) . in south africa ,
class a and d esbls and pampc were present , and the prevalence ranged from 8.8 to 13.1% in hospitals and was 0.3 and 4.7% in two communities ( 7480 ) .
in algerian hospitals , esbls existed in 16.431.4% of the samples . class a esbls were most common , but plasmid - encoded ampc ( pampc ) was also present ( 1622 ) . in egypt , esbls were found in 1142.9% of samples in both hospitals and communities ; the genes involved were class a esbls ( 2325 ) . in guinea - bissau and libya , class a and d esbls and a carbapenemase
were found in 32.6 and 16% , respectively , in rectal or stool samples ( 26 , 27 ) . in morocco ,
class a and d esbls , pampc , and carbapenemases were found in hospital settings ( 2830 ) . in the community
setting , class a and d esbls were found in between 1.3 and 7.5% of acquired urine samples ( 3133 ) . in tunisia , class a and d esbls , pampc , and carbapenemases were present , and the prevalence ranged from 11.7 to 77.8% in hospitals and was 0.7 and 7.3% in two communities ( 3451 ) .
in ethiopia and kenya , 62.8 and 37.4% , respectively , of hospital and community samples were esbls ( 52 , 53 ) .
class a esbls and pampc were present in the kenyan sample ( 53 . in samples taken from kenya and malawi , class
a and d esbls were found ( 54 ) . in rwanda , esbls were found in 38.3% of hospital urine samples and in 5.9% of community urine samples ( 55 ) . in tanzania ,
class a esbls were found in various samples from hospital settings ( 56 , 57 ) .
in cameroon , class a and d esbls were found in 55.3 and 82.8% of hospital stool samples and in 17.2% of community stool samples ( 58 , 59 ) . in the central african republic , esbls were found in 11.3% of community urine samples ( 60 ) .
in ghana and mali , class a esbls were found in 49.4 and 63.496% , respectively , in hospital and community samples ( 6164 ) . in niger ,
40% of hospital samples carried class a esbls or pampc ( 65 ) . in nigeria ,
class a and d esbls and pampc were found in hospital settings , and the prevalence ranged from 10.3 to 27.5% ( 6671 ) . in a mixed sample from a hospital and a community ,
class a and d esbls were found in 10% of community stool samples ( 73 ) .
in south africa , class a and d esbls and pampc were present , and the prevalence ranged from 8.8 to 13.1% in hospitals and was 0.3 and 4.7% in two communities ( 7480 ) .
this review indicates that esbl - producing enterobacteriaceae are a large problem in african healthcare institutions and communities . in patients treated in african hospitals
, the prevalence of esbl - producing enterobacteriaceae has been shown to vary between countries and the type of specimen studied .
there is a trend of higher prevalence of esbl in stool samples than in other specimens .
this is noticeable in the tunisian setting , where a large amount of studies are available . in two hospitals studied ( study periods : 19992005 and 2010 ) ,
esbls have increased from 11.7 to 77.8% among k. pneumoniae ( 42 , 49 ) .
in other settings , the trend is not noticeable among the few studies available . in the studied countries in africa ,
the prevalence is widely different : in algeria , it was between 16.4 and 31.4% in mainly urine samples ( 1618 , 21 ) and even 99% among salmonella enterica in stool samples ( 19 ) ; 19 and 42.9% , respectively , in urine and stool samples in egypt ( 23 , 24 ) ; 32.6% among stool samples in guinea - bissau ( 26 ) ; 11.777.8% in mainly urine , blood , and stool samples from tunisia ( 40 , 42 , 46 , 51 ) ; 62.8% in stool and blood samples from ethiopia ( 52 ; 38.3% in urine samples from rwanda ( 55 ) ; 55.3 and 82.8% in stool samples from cameroon ( 58 , 59 ) ; 10.327.5% in mainly urine and stool samples from nigeria ( 66 , 6972 ) ; and 
 8.813.1% in urine , nasopharyngeal , and wound samples from south africa ( 74 , 75 , 77 ) .
the most common type of genes involved in the african hospital strains of esbl is class a esbls .
ctx - m-15 is the most prevalent gene in a high proportion of the samples , disregarding country .
it is usually combined with other types of ctx - m , tem , and shv genes ( 1719 , 22 , 25 , 28 , 29 , 34 , 38 , 4043 , 46 , 51 , 53 , 5659 , 6567 , 69 , 70 , 78 ) .
there is a high proportion of class d esbls existent , mainly oxa-1 , and it has been found in between 3.3 and 93.3% of the studied isolates ( 34 , 38 , 40 , 53 , 54 , 58 , 59 , 67 , 69 , 78 , 80 ) .
pampc genes exist in some isolates , mainly dha-1 and cmy-2 ( 16 , 18 , 21 , 28 , 29 , 32 , 49 , 50 , 53 , 65 , 69 , 79 ) , but because of the different classifications of esbls , these are not always included in the analyses performed in the studies .
the ndm-1 gene was found in three samples taken from urine , blood , and an abscess from two patients in morocco ( 29 , 30 ) , and the oxa-48 gene was found in a rectal swab sample from a patient originating from libya ( 27 ) .
the presence of carbapenemase genes is a risk for future use of antimicrobial treatment in the region . in the community
setting , esbl - producing enterobacteriaceae have a lower prevalence than in the hospital : 6.7% of healthy students in cameroon ( 58 ) , 1.3% in a moroccan community ( 33 ) , 5.9% in rwandan outpatients ( 55 ) , 2.7% in a healthy community in nigeria ( 72 ) , 11.3% of outpatients in central african republic ( 60 ) , 10% of healthy children in a remote village in senegal ( 73 ) , and 4.7% in a referral site in south africa ( 77 ) .
the genes involved in the community were the same as in the hospital setting . to solve the problem of esbl - producing enterobacteriaceae and other types of resistant bacteria , prevention is crucial and surveillance of antimicrobial resistance is needed to guide prevention interventions .
because of globalization , including international travel , it is important to have a global approach to antibiotic resistance .
the majority of the studies in this review are performed in northern or southern africa , leaving a large gap in the areas in between .
future research should focus on areas where research is scarce , describing the current situation in healthcare services and increasing the consistent surveillance to follow the changes in prevalence and incidence , making relevant interventions possible on both local and global levels .
esbls ( class a and d ) are common in africa , with the gene ctx - m-15 being most prevalent , but other types , such as pampc and carbapenemases , also exist .
surveillance of antimicrobial resistance needs to be implemented in africa to tailor interventions targeted at stopping the dissemination of esbl - producing enterobacteriaceae .
 introduction 
 enterobacteriaceae producing extended - spectrum beta - lactamases ( esbl ) has been found all over the world , and risk factors for acquiring these bacteria involve hospital care and antibiotic treatment . 
 surveillance studies are present in europe , north america , and asia , but there is no summarizing research published on the situation in africa.aimthis review aims to describe the prevalence of esbl - producing enterobacteriaceae in hospital and community settings in africa and the esbl genes involved.methoda non - systematic literature search was performed in pubmed . 
 all articles published between 2008 and 2012 were screened and read in full text . 
 relevant articles were assessed for quality of evidence and included in the review . 
 articles were divided into regional areas in africa and tabulated.resultsesbl-producing enterobacteriaceae in hospitalized patients and in communities varies largely between countries and specimens but is common in africa . 
 esbls ( class a and d ) and plasmid - encoded ampc ( pampc ) were regularly found , but carbapenemases were also present.conclusionesbl-producing enterobacteriaceae in hospital and community settings in africa is common . 
 surveillance of antimicrobial resistance needs to be implemented in africa to tailor interventions targeted at stopping the dissemination of esbl - producing enterobacteriaceae . 
Introduction
Method
Results
Northern Africa
Eastern Africa

Central Africa
Western Africa
Southern Africa
Discussion
Conclusion
Competing interest and funding