Antibiotic susceptibility of clostridium difficile isolates from adult patients at two Jamaican hospitals. Clinical and epidemiological implications

The susceptibility of 39 toxin producing Clostridium difficile isolates from stools of hospitalized patients was determined, by disc diffusion, to six antibiotics. All but one isolate (toxin A negative) produced toxin A and Toxin B. A wide variation in susceptibility to clindamycin, tetracycline and chloramphenicol was noted. Erythromycin and cotrimoxazole showed a clear-cut discrimination in resistance and susceptibility, while all isolates were sensitive to vancomycin. Erythromycin sensitive isolates demonstrates a significant association with diarrhoea (60.9 percent, 14/23, p<0.001). These strains were predominantly found at the University Hospital of the West Indies (UHWI, 94.1 percent, 16/17). Strains resistant to erythromycin and clindamycin together were commonly found at the National Chest Hospital (NCH, 68.2 percent, 15/22). All erythromycin sensitive strains found at the NCH were from patients transfered to that hospital. These findings suggest that there is a common strain of C difficile (erythrmycin resistant) at the NCH different from that found at the UHWI; the resistant pattern seen with isolates from the NCH was typical of toxigenic serogroup C strain and could be typed by the disc diffusion method. Patients at the NCH who were colonized with either of the two strains of C difficile were likely to get diarrhoea, once there suppression of the normal microflora by antibiotics and colonic over growth with C difficile. (AU)

Prevalence and characteristics of Staphylococcus aureus strains isolated from bulk and composite milk and cattle handlers

The prevalence and characteristics of Staphylococcus aureus strains isolated from bulk and composite milk and from cattle handlers on dairy farms in Trinidad were determined. S. aureus strains isolated from all 175 bulk milk samples tested (100 percent) while 280 of 287 composite milk samples (97.6 percent) yielded S. aureus. The mean counts of S. aureus in bulk milk ranged from 5.9 x 10(3) to 1.2 x 10(5) CFU/ml compard with mean S. aureus counts in composited milk which ranged from 2.4 x 10(3) to 3.0 x 10(4) CFU/ml. Of the 105 strains of S. aureus from bulk milk tested, 45 (42.9 percent) were enterotoxigenic elaborating staphylococcal enterotoxin A (SEA), SEB, SEC, SED, or a combination compared to 69 of 146 strains (47.3 percent) recovered from composite milk which were enterotoxigenic but the difference was not statistically significant (P > = 0.05; chi 2). Twenty-two of 42 bulk milk samples containing enterotoxigenic S. auerus (52.4 percent) had counts of the organism which exceeded 10(4) CFU/ml. For S. aureus strains isolated from cattle handlers, 66 of 146 (45.2 percent) were enterotoxigenic. Prevalence of resistance to nine antimicrobial agents tested was 18.7 percent and 12.9 percent among bulk milk and composite milk isolates, respectively, compared to 49.3 percent and 69.5 percent among isolates from human anterior nares and hand swabs, respectively. Resistance to ampicillin and penicillin was highest among both milk (12.2 percent) and human (53.6 percent) isolates of S. aureus, and the difference was statistically significant (P < or = 0.001); chi 2). It was concluded that bulk milk containing relatively high counts of enterotoxigenic S. aureus may constitute a health hazard to consumers(AU)

Prevalence and characteristics of Staphylococcus aureus strains isolated from bulk and composite milk cattle handlers

The prevalence and characteristics of Staphylococcus aureus strains isolated from bulk and composite milk and from cattle handlers on dairy farm all 175 bulk milk samples tested (100 percent) while 280 of 287 composite milk samples (97.6 percent) yielded S. aureus. The mean counts of S. aureus in bulk milk ranged from 5.9 x 10(3) to 1.2 x 10(5) CFU/ml compared with mean S. aureus counts in composite mild which ranged from 2.4 x 10(3) to 3.0 x 10(4) CFU/ml. Of the 105 strains of S. aureus from bulk milk tested, 45 (42.9 percent) were enterotoxigenic elaborating staphylococcal enterotoxin A (SEA), SEB, SEC, SED, or a combination compared to 69 of 146 stains (47.3 percent) recovered from composite milk which were enterotoxigenic, but the difference was not statistically significant (P > 0.05; chi 2). Twenty-two of 42 bulk milk samples containing enterotoxigenic S. aureus (52.4 percent) had counts of the organism which exceeded 10(4) CFU/ml. For S. aureus strains isolated from cattle handlers, 66 of 146 (45.2 percent) were enterotoxigenic. Prevalence of resistance to nine antimicrobial agents tested was 18.7 percent and 12.9 percent among bulk milk and composite milk isolates, respectively, compared to 49.3 percent and 69.5 percent among isolates from human anterior nares and hand swabs, respectively. Resistance to ampicillin and penicillin was highest among both milk (12.2 percent) and human (53.6 percent) isolates of S. aureus, and the difference was stastically significant (P < or in 0.001; chi 2). It was concluded that bulk milk containing relatively high counts of enterotoxigenic S. aureus may constitute a health hazard to consumers(AU)

Microbiological analysis of "black pudding", a Trinidadian delicacy and health risk to consumers

The prevalence of Salmonella, Escherichia coli and Staphylococcus aureus in black pudding which originated from local vendors and supermarket in Trinidad were determined. The enterotoxigenicity of S. aureus strains and occurrence of 0157:H7 strains among E. coli isolates were also investigated. For the 100 black puddings each sampled from supermarkets and vendors, the mean total aerobic plate count (TAPC) per g was 1.8 x 10 (7) the mean total aerobic plate count (TAPC) per g was 1.8 x 10 (7) +/- 1.5 x 10 (7) and 1.5 x 10(8) +/- 2.3 x 10 (8), respectively. E. coli was isolated from 56 (56.0 percent) black pudding samples from supermarkets with a mean count per g of 9.2 x 10 (6) +/- 7.9 x 10 (6) compared to the prevalence of 79 percent (79 nof 100) and mean count per g of 3.2 x 10 (7) +/- 4.7 x 10 (7) for samples from local vendors. The differences between the prevalences was statistically significant (P < or = 0.0001; chi 2). Only 1 (2.2 percent) of 45 strains of E. coli from supermarket-purchased pudding tested, was an 0157:H7 strain compared to 9 (13.3 percent) of 66 strains of E. Coli from vendor-sold black puding. The difference was not statistically significant (P) or = 0.05; chi 2). Five (5.0 percent) of 100 black pudding samples from supermarkets utyielded Salmonella. wih S. ohio being the predominant serotype. For vendor-sold black pudding, however, 11 (11.0 percent) samples were positive for Salmonella with a new serotype, S. unmamed (4, 12:d-_ being responsible for 50 percent (6 of 12) of isolates from this source. Forty samples each of black pudding from supermarkets and vendors were all (100.0 percent) positive for S. aureus with mean counts per g being 3.1 x 10 (5) +/- 8.8 x 10(5) and 3.3 x 10 (6) +/- 7.7 x 10 (6), respectively. Overall, 27 (33.8 percent) of 80 strains of S. aureus tested were enterotoxigenic producing staphylococcal enterotoxins A(SEA), SEB, SEC, SED or a combination. It was concluded that black pudding poses a high risk to consumers based on the prevalence, microbial load and toxigenicity of the pathogens detected. (AU)

Characteristics of Staphylococcus aureus strains isolated from clinical and non-clinical human sources in Trinidad: susceptibility to bacteriophages and antimicrobial agents, and toxigenicity

The susceptibility of Staphylococcus aureus strains isolated from human clinical and non-clinical sources in Trinidad to bacteriophages and antimicrobial agents was determined. The ability of the strains to produce enterotoxins and toxin shock syndrome toxin-1 (TSST-1) was also investigated. Of the 554 strains tested, 454 (81.8 percent) were susceptible to international phage set (IPS) phages with strains isolated from bacteriuria (57.1 percent) and bacteremia (53.3 percent) having a low sensitivity compared to isolates from aspirates (87.3 percent) and anterior nares (97.4 percent). All sources combined, strains were most susceptible to phages belonging to several groups (mixed). Overall, 419 (75.6 percent) strains were resistant to one or more of nine antimicrobial agents tested. Resistance to penicillin was most prevalent, with 413 (74.5 percent) strains found to be resistant. Prevalence of resistance to tetracycline, gentamicin, oxacillin, cefuroxime and ciprofloxacin was 5.1 percent, 2.0 percent, 0.7 percent, 0.4 percent and 0.4 percent respectively. Of the 554 strains tested, 307 (55.4 percent) produced staphylococcal enterotoxins A (SEA), B (SEB), C (SEC) and D (SED) singly or in combination. Strains recovered from high vaginal swabs were least enterotoxigenic (40.0 percent) as compared to umbilical infection isolates which were most enterotoxigenic (78.9 percent). TTST-1 was produced by 95 (19.0 percent) out of 449 strains tested, with isolates from bacteriuria found to be most toxigenic (33.3 percent). It was concluded that the S. aureus strains tested were highly susceptible to bacteriophages and antimicrobial agents (except penicillin) and that enterotoxigenic and TSST-1 producers were widespread and have an aetiologic potential.(Au)

Escherichia coli in gastroenteritis of children in London and Jamaica

The jejunal and stool flora of children with gastroenteritis in London and in Jamaica was examined. Although bacterial colonization of the small bowel was commonly detected, it was unusual to find the same serotype of E.coli in both jejunum and stool, and none of the jejunum strains of E.coli produced either heat-labile or heat-stable enterotoxin. Some strains of E.coli causing infant gastroenteritis are neither toxigenic nor invasive, and other mechanisms must be sought to account for their pathogenicity (AU)