Lactobacillus endocarditis

Two cases of endocarditis due to Lactobacillus plantarum and Lactobacillus casei var. rhamnosus are described. Both patients were successfully treated medically. The response of the two isolates to a range of concentrations of penicillin in an apparatus which continuously monitored growth is reported. The strain of L. casei var. rhamnosus was found to be penicillin tolerant. The use of a combination of a penicillin with gentamicin to treat endocarditis due to penicillin tolerant strains of lactobacillus is discussed. The criteria for selecting oral agents to follow intravenous therapy are assessed also.

Selective and differential medium for the primary isolation of members of the Proteeae

A new differential and selective medium for the isolation of members of the Proteeae, PIM (Proteeae isolation medium) agar, was developed and evaluated. The medium relies on the ability of all members of the Proteeae (with the exception of a very few Morganella morganii strains) to produce a dark brown pigment in medium containing DL-tryptophan. An additional differential property, tyrosine degradation, was also demonstrated by the medium. Members of the Proteeae appeared as dark brown colonies with a halo of clearing of fine tyrosine crystals when cultured on PIM agar. Occasional strains of Citrobacter sp. and Pseudomonas aeruginosa may degrade tyrosine, but none has the ability to produce dark brown pigmentation on PIM agar. Quantitative recovery studies showed that the addition of 5 mg of clindamycin per liter suppressed gram-positive bacteria without inhibiting any strains of the Proteeae. The addition of 100 mg of colistin per liter made the medium highly selective for strains of the Proteeae, but approximately 10% of the strains were not isolated, thus making this formulation unsuitable for general surveys of the occurrence of members of the Proteeae. PIM agar should aid the investigation of episodes of cross infection caused by members of the Proteeae and the isolation of the new species of the Proteeae recently described.

Severe campylobacter infection in children

Children suffering from Campylobacter jejuni infection and who were admitted to children's hospitals in Bristol and Newcastle over a period of 2 years are reviewed. Gastro-intestinal disease caused by C. jejuni was as common as that due to Salmonella spp. Three neonates suffered particularly severe infections which resembled necrotising enterocolitis. One such case is described.

Evolution of an R plasmid from a cryptic plasmid by transposition of two copies of Tn1 in Providencia stuartii

Examination of a series of isolates of Providencia stuartii collected over an 18 month period from a chronic-care patient at Bristol Royal Infirmary revealed the emergence of resistance to carbenicillin. Resistance was mediated by a 47 kb plasmid which transferred by conjugation to a plasmid-free strain of P. stuartii but not to Escherichia coli. Carbenicillin-sensitive isolates were either plasmid-free or contained a 36 kb cryptic plasmid. Restriction endonuclease mapping of this plasmid showed it to be closely related to 32 kb and 34 kb cryptic plasmids reported previously in P. stuartii from Bristol. Mapping of the R plasmid showed it to be derived from the 34 kb cryptic plasmid by transposition of two copies of Tn1.

Comparative in-vitro activity of quinolone carboxylic acids against Proteeae

The in-vitro susceptibilities of 198 isolates of precisely identified Proteeae species to six quinolone antimicrobials were determined. Significant differences in susceptibility patterns among various Proteeae to the quinolones examined were demonstrated. Although Providencia stuartii was found to be the most resistant to quinolones including the very active agent ciprofloxacin, fully speciated Prov. rettgeri were also markedly resistant as well. in contrast Prov. alcalifaciens was extremely sensitive to these agents. Some strains of Proteus penneri were more resistant to the three newer compounds (ciprofloxacin, enoxacin and norfloxacin) than strains of Pr. vulgaris suggesting that recognition of this species may be important in surveys of the in-vitro activity of antibiotics. Pr. mirabilis and Morganella morganii were very sensitive to the newer agents. The patterns of resistance seen in the three newer agents were reflected in the older agents acrosoxacin and cinoxacin. Accurate speciation of Proteeae in surveys of susceptibilities to antimicrobial agents is important if misleading results are not to be reported.

Cryptic plasmids in hospital isolates of Providencia stuarti

The distribution of cryptic plasmids among 123 isolates of Providencia stuarti from a hospital ward during a prospective epidemiological study is reported. Two closely related stable plasmids (34 Kb and 36 Kb) were identified by restriction endonuclease digest analysis of plasmid DNA. One or other of these cryptic plasmids was carried by 40 isolates, the remainder were plasmid-free. A higher proportion of one cryptic plasmid (CPT-A) was found in environmental isolates than in isolates from patients. The serotype of all isolates of P. stuarti was O63 and they were epidemiologically related. Two of the eight patients colonised by P. stuarti carried all three possible variants: plasmid-free (PFI) strains or strains containing cryptic plasmid A (CPT-A) or cryptic plasmid B (CPT-B). The epidemiological significance of these results is discussed.

Capnocytophaga ochracea infection: two cases and a review of the published work

Bacteria of the genus Capnocytophaga are recently recognised pathogens which may cause oral disease and subsequent septicaemia in the immunocompromised host. We present two cases of infection caused by Capnocytophaga ochracea; a soft tissue infection in an immunologically normal patient and an episode of septicaemia in a child with leukaemia. The microbiology, pathogenicity, and antimicrobial susceptibility of the genus capnocytophaga are reviewed.

Infection with netilmicin resistant Serratia marcescens in a special care baby unit

An outbreak of colonisation and infection with a netilmicin resistant strain of Serratia marcescens occurred in a special care baby unit. S marcescens was isolated from a total of 13 babies; significant infection occurred in five, of whom two died. Epidemiological investigation failed to detect a common source but gastrointestinal colonisation of babies formed a prolonged and possibly important reservoir for infection. Containment proved difficult until the unit was closed to new admissions, and even then spread to a temporary unit ensued. O Serotyping and bacteriophage typing disclosed a single epidemic strain. This produced an aminoglycoside acetylating enzyme (AAC(6')) conferring resistance to netilmicin and tobramycin and moderate resistance to amikacin. Use of gentamicin resulted in the isolation of serratia with increased resistance to all aminoglycosides, and, similarly, increased resistance to third generation cephalosporins emerged with their use.

Computer-assisted determination of antibiotic susceptibility in photometer-read microtiter plates

A method for the computer-assisted determination of microdilution minimal inhibitory concentrations by using a Dynatech MR580 through-the-plate reading photometer is presented. The method was evaluated by comparison with manual determination of the minimal inhibitory concentrations of 12 antibiotics for 115 bacterial isolates. The two methods agreed within one dilution in 98.3% of the cases.

Serious nosocomial infection caused by Morganella morganii and Proteus mirabilis in a cardiac surgery unit

In July and August 1981, five patients in the cardiac surgery unit of the Bristol Royal Infirmary developed septicemia caused by Morganella morganii, Proteus mirabilis, or both of these species. Three of the patients had serious wound infections, and three of the patients died. Typing of the M. morganii isolates by O-serotyping and of the P. mirabilis isolates by O-serotyping, proticine production and sensitivity, and the Dienes reaction confirmed cross infection by both species. Although M. morganii has been regarded as a relatively unimportant human pathogen in the past, it may prove to be an important cause of nosocomial infection in the future.

Cellulitis in children caused by Haemophilus influenzae type b

Of 31 episodes of invasive infection by Haemophilus influenzae capsular type b, occurring in children during a 26-month period, five (16 per cent) had cellulitis as the presenting feature. In four of the five patients bacteraemia was detected. This frequency of presentation is not reflected in reports in the British literature. Prompt recognition of this aetiology of cellulitis is important for effective chemotherapy.

Comparative in vitro activity of semisynthetic penicillins against Proteeae

The in vitro susceptibilities of 181 isolates of precisely identified Proteeae species to five semisynthetic penicillins were determined with low and high inocula. Significant differences in susceptibility patterns among various Proteeae species to the penicillins examined were demonstrated. Providencia stuartii was clearly distinguished from Providencia alcalifaciens by its greater resistance to the antibiotics tested.

Prospective survey of fecal, urinary tract, and environmental colonization by Providencia stuartii in two geriatric wards

A prospective survey of fecal, urinary tract, and environmental colonization by Providencia stuartii in two wards was undertaken over a 5-month period. Eight of 53 male patients and 2 of 89 female patients were colonized with the endemic serotype O:63. Two patterns of colonization were found on the male ward. Two patients had persistent urinary tract colonization with no detectable fecal carriage. The other patients had fecal carriage, in some cases persistent, with intermittent urinary tract colonization. The ward environment was in general not contaminated. This study demonstrates that fecal colonization of patients by P. stuartii may be an important and previously underestimated nosocomial reservoir.

Overwhelming post-splenectomy infection with group B Streptococcus

A case of overwhelming post-splenectomy infection is described. This occurred 10 years after splenectomy in an otherwise normal male adult. The infecting organism, β-haemolytic Streptococcus Group B, is usually of low pathogenicity, but in this case caused profound hypotension, jaundice and the shock lung syndrome. Overwhelming post-splenectomy infection with this organism has not previously been reported.