Hepatitis B virus and hepatitis C virus in medical waste handlers in Tripoli, Libya.

Medical waste handlers (MWHs) are at risk of exposure to serious viral infections. No data are available on the prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV) or human immunodeficiency virus (HIV) among MWHs in Libya. During a one-year period (January to December 2004) blood samples from 300 (59 females) MWHs employed by a local contractor in Tripoli and 300 blood samples from non-medical waste handlers (NMWHs) who had no direct or indirect contact with medical waste were examined for HBV, HCV and HIV using enzyme-linked immunosorbent assays. HBV was detected in 7 (2.3%) and 1 (0.3%) and HCV in 8 (2.7%) and 0 (0.0%) of MWHs and NMWHs, respectively. Significant differences were observed in the detection rates of HBV (OR: 7.14; P<0.04) and HCV (OR: undefined; P<0.005) in MWHs when compared with NMWHs. HIV was not detected in both groups. Of the MWHs studied, 21% were immunised against HBV and 7% were trained to handle medical waste. In addition, 99.7% wore overalls, 57.7% thick disposable gloves, 55% boots and 17.7% masks while handling medical waste. In conclusion, prevalence rates of HBV and HCV were significantly higher in MWHs than those in NMWHs examined. Training, immunisation, and post-exposure protection of MWHs, in addition to proper management of medical waste by the health authorities, may significantly reduce the risk of acquiring infectious agents by MWHs in Libya.

Phenotypic and genetic characterization of enteropathogenic Escherichia coli (EPEC) and entero-aggregative E. coli (EAEC) from diarrhoeal and non-diarrhoeal children in Libya.

A total of 50 Escherichia coli strains isolated in a Libyan hospital (20 from children with diarrhoea and 30 from healthy children) were investigated for their pathotypes and virulence traits. Altogether nine eae-positive (enteropathogenic E. coli, EPEC) and nine aggR-positive (entero-aggregative E. coli, EAEC) strains were identified. Significantly (P=0.001) more EPEC strains were identified from diarrhoeal patients (n=8) than from healthy controls (n=1), while six EAEC strains were identified from diarrhoeal and three from healthy children. Typical (eae(+), EAF(+), bfp(+)) EPEC strains (n=6) belonged to classical EPEC serogroups O55, O114, O127 and showed localized adherence on Hela cells. EAEC strains revealed genetic heterogeneity but uniformly adhered to HeLa cultures in an entero-aggregative adherence pattern. Antibiotic resistance frequently, characterized the strains. Sixty-eight percentage of the strains were resistant against at least one antibiotic and 30% harbored a class 1 integron independently of their clinical background. This is the first report from North Africa demonstrating the significance of EPEC and EAEC.

Carriage by the German cockroach (Blattella germanica) of multiple-antibiotic-resistant bacteria that are potentially pathogenic to humans, in hospitals and households in Tripoli, Libya.

Using standard bacteriological procedures, 403 cockroaches (Blattella germanica) collected in Tripoli, from hospitals or the households surrounding the hospitals, were examined for bacteria that are potentially pathogenic to humans. Almost all of the cockroaches (96.1% of the 253 from hospitals and 98.7% of the 150 from households) were found to be carrying potentially pathogenic bacteria, with similar mean burdens of 3.2 x 10(5) colony-forming units (cfu) (range=0-1.4 x 10(7)) for each hospital cockroach and 1.9 x 10(5) cfu (range=0-3.1 x 10(6)) for each household cockroach (P>0.05). Overall, 27 and 25 species of potential pathogen were isolated from the hospital and household cockroaches, respectively, with Klebsiella, Enterobacter, Serratia and Streptococcus predominant. Carriage of species of Serratia was significantly more common among the hospital cockroaches than among the household cockroaches, whereas carriage of Klebsiella, Enterobacter, Citrobacter and Aeromonas was significantly more common among the household cockroaches than among the hospital. Multiple resistance, to at least six different antibiotics, was more commonly observed among the enteric bacteria isolated from the hospital cockroaches than among those recovered from the household cockroaches. Overall, >30% of the isolates of Enterobacteria recovered were each resistant to at least four antimicrobial agents, and 95% of the Pseudomonas isolates were each resistant to at least eight such agents. Cockroaches may play an important role in the spread of multiple-antibiotic-resistant, bacterial pathogens within the hospitals and surrounding communities of Tripoli and other, similar cities. The local health and environmental authorities need to be encouraged to treat B. germanica infestations seriously and to control them quickly and effectively.

Carriage by the housefly (Musca domestica) of multiple-antibiotic-resistant bacteria that are potentially pathogenic to humans, in hospital and other urban environments in Misurata, Libya.

Using standard microbiological procedures, bacteria that are potentially pathogenic to humans were isolated from 150 houseflies collected in the Libyan city of Misurata (50 flies each from the Central Hospital, streets and abattoir). Salmonella spp., Yersinia enterocolitica and Edwardsiella tarda were isolated from flies collected on the streets and in the abattoir but not from those collected in the hospital. Shigella sonnei was detected in just one fly, which was collected in the abattoir. Of the flies collected in the hospital, streets and abattor, 42%, 42% and 32% were positive for Escherichia coli, 70%, 50% and 62% for Klebsiella spp., 2%, 20% and 10% for Aeromonas spp., 96%, 36% and 34% for Pseudomonas spp., 20%, 12% and 16% for Staphylococcus spp., and 24%, 22% and 18% for Streptococcus spp., respectively. When the antibiotic susceptibilities of the fly isolates were investigated, the Enterobacteria isolated from the houseflies collected in the hospital were found to be resistant to significantly more of the commonly used antibiotics that were tested than the Enterobacteria isolated from the flies caught in the streets or abattoir. Whatever the source of the flies from which they were collected, the Pseudomonas isolates frequently showed resistance to multiple antibiotics, with >50% each being resistant to at least 10 antimicrobial agents. Two isolates of Sta. aureus (both from flies collected in the hospital) were resistant to methicillin. The present study supports the belief that the housefly is a potential vector of multiple-antibiotic-resistant, pathogenic bacteria, including methicillin-resistant Sta. aureus, in the hospital environment. Given their mobility, it seems likely that houseflies carry such pathogens from hospitals to surrounding communities, and vice versa.

Serotypes, virulence factors, antibiotic sensitivity, beta-lactamase activity and plasmid analysis of Salmonella from children with diarrhea in Tripoli (Libya).

A total of 21 Salmonella strains isolated in Libya (16 from children with diarrhea and 5 from healthy controls) were serotyped and studied for their cell invasive ability, production of cytotoxin, antibiotic susceptibility, beta-lactamase activity and plasmid profiles. Eight different serotypes of Salmonella were identified: 6 S. saintpaul, 4 S. wien (1 from control), 2 S. newport, 2 S. muenchen (1 from control), 2 S. typhimurium (1 from control), 2 S. hadar (1 from control), 2 S. reading (1 from control), 1 S. kottbus. Twenty (95%) were positive in the invasiveness assay using HeLa cells, and all (100%) were negative for cytotoxin production in HT29 cells. More than 40% were resistant to ampicillin, cefalexin, cefamandole, cefoperazone, chloramphenicol, gentamicin, mezlocillin and trimethoprimsulphamethoxazole and 100% were susceptible to the new quinolones. Most (67%) of the strains harbored plasmids and 43% produced beta-lactamase. A strong association was observed between the presence of more than one plasmid, beta-lactamase activity, and multiple-resistance to antimicrobial agents and serotypes S. saintpaul and S. wien. Curing experiments with acridine orange showed that 2 plasmids (33 and 1.4 megadaltons) might be responsible for the resistance to chloramphenicol and gentamicin. The present study demonstrated that multiple-resistant salmonellae are widespread in Libya and the resistance is mainly plasmid mediated.

Prevalence, species differentiation, haemolytic activity, and antibiotic susceptibility of aeromonads in untreated well water.

The use of untreated water for drinking and other activities have been associated with intestinal and extraintestinal infections in humans due to Aeromonas species. In the present study aeromonads were isolated from 48.7% of 1,000 water samples obtained from wells and other miscellaneous sources. Aeromonas species were detected in 45% of samples tested in spring, 34.5% in summer, 48% in autumn and 60% of samples tested in winter. Speciation of 382 strains resulted in 225 (59%) being A. hydrophila, 103 (27%) A. caviae, 42 (11%) A. sobria and 11 (3%) atypical aeromonads. Of 171 Aeromonas strains tested for their haemolytic activity, 53%, 49%, 40% and 37% were positive in this assay using human, horse, sheep and camel erythrocytes respectively. The results obtained indicate that potentially enteropathogenic Aeromonas species are commonly present in untreated drinking water obtained from wells in Libya (this may also apply to other neighbouring countries) which may pose a health problem to users of such water supplies. In addition, ceftriaxone and ciprofloxacin are suitable drugs that can be used in the treatment of Aeromonas-associated infections, particularly in the immunocompromised, resulting from contact with untreated sources of water.

Isolation and haemolytic activity of Aeromonas species from domestic dogs and cats.

Rectal swabs from 120 domestic dogs and 15 domestic cats were examined for Aeromonas species using alkaline peptone water (pH 8.6) as the enrichment medium and blood agar containing 15 mg/l ampicillin as the plating medium. Aeromonads were isolated from 13 (10.8%) dogs and from 1 (6.7%) cat. Of the 14 aeromonads isolated in the present study only 9 were available for speciation and testing in the haemolysin assay. Of these 5 were A. sobria (including one from a cat), 2 were A. hydrophila and 2 were A. caviae. Six were positive in the haemolysin assay; 4 A. sobria (one from a cat) and 2 A. hydrophila. The presence of haemolysin producing-Aeromonas species in the faeces of domestic dogs and cats may pose a public health problem for humans who come into contact with such animals.

Characterization of virulence factors of Aeromonas isolated from children with and without diarrhoea in Tripoli, Libya.

During September 1992-August 1993, stool samples from 157 children with diarrhoea and 157 matched healthy controls were examined for the presence of Aeromonas and other enteropathogens. Aeromonas strains were tested for haemolytic activity, haemagglutination patterns, and antibiotic susceptibility. In total, 62 Aeromonas were isolated, of which 27 (17.2%) were from children with diarrhoea and 35 (22.3%) from healthy controls. Only 23 (14.6%) of the diarrhoeal children and 28 (17.8%) of the healthy controls were positive for Aeromonas; of which, 4 (2.5%) of the diarrhoeal children and 6 (3.8%) of the healthy controls showed multiple species. Aeromonas hydrophila was isolated from 5 (3.2%) children with diarrhoea and from 9 (6.4%) controls, A. veronii bv sobria from 8 (5.1%) and 7 (4.5%), A. caviae from 13 (8.3%) and 17 (10.8%), and A. schubertii from 1 (0.6%) and 2 (1.3%) respectively. No significant difference in the haemolytic activity of Aeromonas was found between diarrhoeal and healthy children. However, a significant difference (p < 0.002) was observed in mannose-resistant haemagglutination (MRHA) by diarrhoeal isolates of Aeromonas (7/27, 26%) compared to the healthy controls (1/35, 3%). Aeromonas strains were uniformly sensitive to ciprofloxacin, gentamicin, and nalidixic acid. The results of this study suggest that A. caviae strains may be associated with diarrhoea in children and MRHA may be used as one of the virulence markers for distinguishing between Aeromonas isolated from diarrhoeal children and healthy controls or environmental isolates.

Enterotoxins and phage typing of Staphylococcus aureus isolated from clinical material and food in Libya.

Enterotoxin was detected in 22 (61.1%) of the 36 S. aureus strains isolated from clinical materials and in 3 (13%) of the 23 S. aureus strains from food samples (P < 0.05). On the basis of individual types of enterotoxin, staphylococcal enterotoxin A (SEA) was produced by 11.1%, SEB by 38.9% and SEC by 22.2% of SS. aureus strains from clinical material. Of the food S. aureus strains, SEC and SED produced by 8.7% and 4.3% respectively. Of the clinical and food S. aureus strains, 52.8% and 39.1%, respectively, were typeable by the 23 phages of International Phage Set. The majority of the typeable S. aureus strains from clinical and food sources belonged to group II being at 22.2% and 17.4% respectively. Furthermore, of the 14 SEB-producing S. aureus, 42.9% were of phage group II. In conclusion, the results obtained indicate that enterotoxin-producing S. aureus strains from clinical materials in Libya are not uncommon; however, certain foods appear not to be the source of such strains. Because of the low susceptibility to bacteriophages shown by S. aureus isolated in Libya, compared to reports from several countries, other methods of typing should be used in conjunction with phage typing in epidemiological investigations concerning this organism.

Bacterial composition of the biofilm on the surface of course sediment of the Danube: with special reference to the clinically important bacteria.

On monthly intervals and over a period of 14 months (November, 1993-December, 1994) biofilm samples from sediments taken at the Szentendre Island on the Danube were culturel and the isolated organisms were examined macromorphologically and micromorphogically and tested for oxidase and catalase production and their ability to oxidise and ferment glucose. The majority (85%) of the strains isolated were catalase positive. 43% were oxidase positive, 38% were glucose oxidisers and only 19% fermented glucose. In the sediment upmost biofilm layers Gram-negatives dominate (10 samples out of 14). A representative set strains has been subjected to complete identification using the Biolog automated identification system. The coryneform bacteria (e.g. Arthrobacter spp.) and members of the genus Rhodococcus dominated the Gram-positive bacteria while the dominant Gram-negative bacteria were facultative H2 autotrophs, methylotrophs (e.g. Xanthobacter flavus, Hydrogenophaga spp.) and different Aeromonas, Enterobacter and Pseudomonas species. Because the water supply of Budapest (the capital of Hungary) comes from bankwall filtred Danube water resources, the presence of clinically important microorganisms (i.e. Aeromonas, Enterobacter, Pseudomonas and Rhodococcus spp) in the Danube-sediments may pose a public health problem to the users (in particular the immunocompromised) of such water supplies.

Haemolytic activity of Aeromonas species isolated in Libya.

Twenty seven Aeromonas strains (5A. hydrophila, 8A. sobria and 14A. caviae) isolated from children with diarrhoea and 34 Aeromonas strains (9A. hydrophila, 7A. sobria an 18A. caviae) isolated from children without diarrhoea were tested from haemolysin production. The results obtained showed that haemolysin production using human, horse or sheep erythrocytes was significantly associated with A.hydrophila and A sobria but not with A.caviae, regardless of whether these strains were isolated from children with or without diarrhoea. Human or horse rather than sheep erythrocytes are recommended for use in the haemolysin assay.

Gas liquid chromatography of amines produced by the Enterobacteriaceae

1. Gas liquid chromatography (GLC) was used to test the production of amines by 85 strains of Enterobacteriaceae. 2. The strains tested produced cadaverine, ß-phenylethylamine, putrescine, iso-amylamine, 2-methylbutylamine and iso-butylamine. 3. Although the overlap in amine production between obviouasly different genera sspecies limits the general applicability of this methology in clinical microbiology, the results obtained limits the general applicability of this methodology in clinical microbiology, the results obtained demonstrate the possibility of differentiating Proteus rettgeri from other Proteus species, Escherichia coli from Proteus species and Salmonella species from Shigella species on the basis of their amine composition. 4. In general, members of the Enterobacteriaceae family produce qualitatively similar amine profiles, thought differing quantitatively in the amounts of individual amines produced. GLC proves to be useful for separating amines and for provididng tentative peak identification

Gas liquid chromatography of amines produced by the Enterobacteriaceae.

1. Gas liquid chromatography (GLC) was used to test the production of amines by 85 strains of Enterobacteriaceae. 2. The strains tested produced cadaverine, beta-phenylethylamine, putrescine, iso-amylamine, 2-methylbutylamine and iso-butylamine. 3. Although the overlap in amine production between obviously different genera and species limits the general applicability of this methodology in clinical microbiology, the results obtained demonstrate the possibility of differentiating Proteus rettgeri from other Proteus species, Escherichia coli from Proteus species and Salmonella species from Shigella species on the basis of their amine composition. 4. In general, members of the Enterobacteriaceae family produce qualitatively similar amine profiles, though differing quantitatively in the amounts of individual amines produced. GLC proved to be useful for separating amines and for providing tentative peak identification.