[Advantages and limits of the surveillance of nosocomial infections from the microbiology laboratory: experience of Meaux hospital]

To estimate the incidence of nosocomial infections (NI) in our hospital and to increase healthcare professionals' awareness of hygiene, a prospective study was performed between January and December 2002 from the microbiology laboratory data. On 1334 suspicions of NI, corresponding to 1062 patients, sent to the hygiene correspondents in each medical care unit, the infection control team received 853 answers (64% of sendings) with 430 NI validated. The incidence rate of NI validated was 1.7 NI/1000 days of hospitalisation and 1.6 NI/100 inpatients. The NI were predominantly related to urinary tract (47%), bloodstream (14%), and lower respiratory tract (12%). Transmission of these informations to medical information department permitted a valorisation of additional 16,000 ISA points. This prospective study permitted to develop a network of hygiene correspondents in every medical care units. None of the medical care units was unharmed by NI but the exhaustive declaration of NI seems difficult to realise. This study permitted to point out some dysfunctionments in the management of invasive procedures and to improve these practices.

Épidémiologie et résistance aux antibiotiques de Streptococcus pneumoniae en Île de France en 2001

OBJECTIVE

The authors wanted to assess the level of Streptococcus pneumoniae antibiotic resistance in Ile de France.

METHOD

In 2001, 637 clinical strains of S. pneumoniae were prospectively collected from 32 microbiology laboratories.

RESULTS

Fifty one percent of strains were isolated from children under 15 years of age and 49% from adults. In children, 76% of strains came from otitis media, 20% from blood culture, in adults most strains (92%) came from blood culture. The overall prevalence of non-susceptible penicillin pneumococci was 61% higher in children (73%) than in adults (50%). Among the non-susceptible penicillin pneumococci 21.8% were resistant (CMI > 1 mg/l). Strains with decreased susceptibility to amoxicillin and cefotaxime were 38% and 17% respectively. Resistant strains to these two drugs (CMI > 2 mg/l) were rare 2.6% and 0.4% respectively. Among other antimicrobial agents, rate of resistance was 63% to erythromycin, 47% to cotrimoxazole, 40% to tetracycline, and 23% to chloramphenicol. The most frequent serogroups were serogroups 19 and 14, respectively 23% and 18%. Serotypes included in heptavalent vaccine covered 90% of children strains under 2 years of age.

CONCLUSIONS

The prevalence of resistance to penicillin was high in children particularly in otitis media pus (76%).

[Update on the susceptibility of streptococci to antibiotics (enterococci and Streptococcus pneumoniae excluded)]

Over the last years, the emergence of resistance to antibiotics has complicated the management of streptococcal infections. The resistance of streptococci to antibiotics is increasing and seems to be linked to the consumption of antibiotics. Resistances to antibiotics have been noted in all species of streptococci and no family of antibiotics is unaffected by resistances. The incidence of resistance to antibiotics varies from one species to another and according to countries. Presently, even though no Streptococcus pyogenes has shown diminished susceptibility to betalactams, this phenomenon has been reported for some strains in the B, C, and G groups, and for up to 56 % of oral streptococci. As for the resistance to macrolides, it reaches as many as 41 % of Streptococcus pyogenes, 46 % of group B streptococci, and 63 % of oral streptococci responsible for severe infections. This evolution is worrying for all streptococci but particularly for oral streptococci which represent a potential reservoir of virulence genes, notably towards Streptococcus pneumoniae. New families of antibiotics as the ketolides or the oxazolidinones appear to be effective in the treatment of streptococcal infections, but it seems that only a policy of control of the consumption of antibiotics could globally decrease the occurrence of resistance.

[Tibial osteitis caused by Pantoea agglomerans after open grade IIIB tibial shaft fracture]

Bone infection is not an uncommon complication of open tibial shaft fractures. We report an unusual case of chronic tibial osteitis caused by Pantoea agglomerans after an open grade IIIB tibial shaft fracture. P. agglomerans, an enterobacteria, was identified on bone samples obtained nine months after the fracture. The infection probably resulted from the initial soil contamination and developed despite fixation and bone covering with a muscle flap performed during the same operative time and adapted intravenous antibiotics.

[Identification of a cephalosporinase susceptible to clavulanic acid in a clinical strain of Serratia fonticola]

We analyzed the beta-lactamase production of a Serratia fonticola isolated for its resistance to cefuroxime (Minimum Inhibitory Concentration > 256 mg/l) in December 1993 from a patient hospitalized in Meaux. The wild strain was resistant to amoxycillin but sensitive to augmentin, that suggested the production of a beta-lactamase susceptible to clavulanic acid. For the wild strain, beta-lactamase production was inducible and only one enzyme with an isoelectric point of 8.12 was detected. beta-lactamase production was 16 mU/mg for non-induced extracts and ranged from 100 to 230 mU/mg in the presence of inducing beta-lactams (enzyme activity was measured with penicillin G as substrate). On a Szybalski gradient a constitutive strain was obtained. Its enzyme production was 13,000 mU/mg. The kinetics and isoelectric points of the enzymes produced by the two strains were identical. This beta-lactamase hydrolyzes penicillins (amoxycillin: Vm = 60 relative to penicillin G = 100, ticarcillin: 15), first generation cephalosporins (cephalothin Vm = 930). However, this enzyme hydrolyzes efficiently oxyimino-cephalosporins: cefuroxime (Vm = 70) and cefotaxime (Vm = 120), but cephamycins are not substrates. Clavulanic acid has a very good affinity for this beta-lactamase (Ki = 0.09 microM) which is inactivated progressively (I50 = 0.045 microgram/ml). These properties shows some similarities with those of the class A beta-lactamases of P. vulgaris RO104 (pI = 8.3), P. penneri 14HBC (pI = 6.65) and the plasmid-mediated extended-spectrum MEN-1 (pI = 8.4).